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-rw-r--r--Makefile2
-rw-r--r--README.md2
-rw-r--r--docs/chapter10/10-grammar.md129
-rw-r--r--docs/chapter10/Makefile12
-rw-r--r--docs/chapter10/README.md359
-rw-r--r--docs/chapter10/example1.gv78
-rw-r--r--docs/chapter10/example1.svg294
-rw-r--r--docs/chapter10/example2a.gv65
-rw-r--r--docs/chapter10/example2a.svg249
-rw-r--r--docs/chapter10/example2b.gv56
-rw-r--r--docs/chapter10/example2b.svg189
-rw-r--r--docs/chapter10/example2c.gv53
-rw-r--r--docs/chapter10/example2c.svg168
-rw-r--r--docs/chapter10/lattice.drawio379
-rw-r--r--docs/chapter10/lattice.gv161
-rw-r--r--docs/chapter10/lattice.svg516
-rw-r--r--src/main/java/com/seaofnodes/simple/GraphEvaluator.java181
-rw-r--r--src/main/java/com/seaofnodes/simple/GraphVisualizer.java13
-rw-r--r--src/main/java/com/seaofnodes/simple/IRPrinter.java71
-rw-r--r--src/main/java/com/seaofnodes/simple/IterPeeps.java6
-rw-r--r--src/main/java/com/seaofnodes/simple/Parser.java238
-rw-r--r--src/main/java/com/seaofnodes/simple/Utils.java26
-rw-r--r--src/main/java/com/seaofnodes/simple/node/AddNode.java2
-rw-r--r--src/main/java/com/seaofnodes/simple/node/BoolNode.java18
-rw-r--r--src/main/java/com/seaofnodes/simple/node/CastNode.java38
-rw-r--r--src/main/java/com/seaofnodes/simple/node/ConstantNode.java4
-rw-r--r--src/main/java/com/seaofnodes/simple/node/IfNode.java3
-rw-r--r--src/main/java/com/seaofnodes/simple/node/LoadNode.java78
-rw-r--r--src/main/java/com/seaofnodes/simple/node/LoopNode.java2
-rw-r--r--src/main/java/com/seaofnodes/simple/node/MemOpNode.java40
-rw-r--r--src/main/java/com/seaofnodes/simple/node/MinusNode.java8
-rw-r--r--src/main/java/com/seaofnodes/simple/node/NewNode.java40
-rw-r--r--src/main/java/com/seaofnodes/simple/node/Node.java92
-rw-r--r--src/main/java/com/seaofnodes/simple/node/NotNode.java24
-rw-r--r--src/main/java/com/seaofnodes/simple/node/PhiNode.java46
-rw-r--r--src/main/java/com/seaofnodes/simple/node/ProjNode.java12
-rw-r--r--src/main/java/com/seaofnodes/simple/node/RegionNode.java45
-rw-r--r--src/main/java/com/seaofnodes/simple/node/ReturnNode.java13
-rw-r--r--src/main/java/com/seaofnodes/simple/node/ScopeNode.java87
-rw-r--r--src/main/java/com/seaofnodes/simple/node/StartNode.java56
-rw-r--r--src/main/java/com/seaofnodes/simple/node/StopNode.java11
-rw-r--r--src/main/java/com/seaofnodes/simple/node/StoreNode.java70
-rw-r--r--src/main/java/com/seaofnodes/simple/node/SubNode.java8
-rw-r--r--src/main/java/com/seaofnodes/simple/type/Field.java60
-rw-r--r--src/main/java/com/seaofnodes/simple/type/Type.java76
-rw-r--r--src/main/java/com/seaofnodes/simple/type/TypeInteger.java27
-rw-r--r--src/main/java/com/seaofnodes/simple/type/TypeMem.java64
-rw-r--r--src/main/java/com/seaofnodes/simple/type/TypeMemPtr.java78
-rw-r--r--src/main/java/com/seaofnodes/simple/type/TypeStruct.java121
-rw-r--r--src/main/java/com/seaofnodes/simple/type/TypeTuple.java30
-rw-r--r--src/test/java/com/seaofnodes/simple/Chapter01Test.java4
-rw-r--r--src/test/java/com/seaofnodes/simple/Chapter03Test.java2
-rw-r--r--src/test/java/com/seaofnodes/simple/Chapter05Test.java12
-rw-r--r--src/test/java/com/seaofnodes/simple/Chapter06Test.java8
-rw-r--r--src/test/java/com/seaofnodes/simple/Chapter07Test.java6
-rw-r--r--src/test/java/com/seaofnodes/simple/Chapter08Test.java5
-rw-r--r--src/test/java/com/seaofnodes/simple/Chapter09Test.java31
-rw-r--r--src/test/java/com/seaofnodes/simple/Chapter10Test.java404
-rw-r--r--src/test/java/com/seaofnodes/simple/SchedulerTest.java74
-rw-r--r--src/test/java/com/seaofnodes/simple/TypeTest.java145
-rw-r--r--src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java209
-rw-r--r--src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java592
-rw-r--r--src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java53
-rw-r--r--src/test/java/com/seaofnodes/simple/fuzzer/FuzzerUtils.java10
-rw-r--r--src/test/java/com/seaofnodes/simple/fuzzer/Reducer.java92
-rw-r--r--src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java498
66 files changed, 6008 insertions, 537 deletions
diff --git a/Makefile b/Makefile
index b5c21b38..c7724bc7 100644
--- a/Makefile
+++ b/Makefile
@@ -70,7 +70,7 @@ tests: $(default_targets)
@$(JVM) org.junit.runner.JUnitCore $(test_cp)
fuzzer: $(default_targets)
- @echo "testing " $(test_cp)
+ @echo "fuzzing " $(test_cp)
@$(JVM) org.junit.runner.JUnitCore com.seaofnodes.simple.FuzzerWrap
diff --git a/README.md b/README.md
index 0f301656..d1e152ae 100644
--- a/README.md
+++ b/README.md
@@ -51,7 +51,7 @@ The Simple language is styled after a subset of C or Java.
* [Chapter 7](docs/chapter07/README.md): `while` statement; looping constructs - eager phi approach.
* [Chapter 8](docs/chapter08/README.md): Looping constructs continued, lazy phi creation, `break` and `continue` statements.
* [Chapter 9](docs/chapter09/README.md): Global Value Numbering. Iterative peepholes to fixpoint. Worklists.
-* Chapter 10: User defined Struct types. Memory effects:
+* [Chapter 10](docs/chapter10/README.md): User defined Struct types. Memory effects:
general memory edges in SSA. Equivalence class aliasing. Null pointer
analysis. Peephole optimization around load-after-store/store-after-store.
* Chapter 11: Global Code Motion - Scheduling.
diff --git a/docs/chapter10/10-grammar.md b/docs/chapter10/10-grammar.md
new file mode 100644
index 00000000..10c80426
--- /dev/null
+++ b/docs/chapter10/10-grammar.md
@@ -0,0 +1,129 @@
+# Grammar for Chapter 10
+
+```antlrv4
+grammar SimpleLanguage;
+
+program
+ : statement+ EOF
+ ;
+
+statement
+ : returnStatement
+ | structDeclaration
+ | declStatement
+ | blockStatment
+ | expressionStatement
+ | ifStatement
+ | whileStatement
+ | breakStatement
+ | continueStatment
+ | metaStatement
+ ;
+
+field
+ : 'int' IDENTIFIER ';'
+ ;
+
+fields
+ : field+
+ ;
+
+structDeclaration
+ : 'struct' IDENTIFIER '{' fields '}'
+ ;
+
+whileStatement
+ : 'while' '(' expression ')' statement
+ ;
+
+breakStatement
+ : 'break' ';'
+ ;
+
+continueStatement
+ : 'continue' ';'
+ ;
+
+ifStatement
+ : 'if' '(' expression ')' statement ('else' statement)?
+ ;
+
+metaStatement
+ : '#showGraph' ';'
+ ;
+
+expressionStatement
+ : IDENTIFIER '=' expression ';'
+ | fieldExpression '=' expression ';'
+ ;
+
+blockStatement
+ : '{' statement+ '}'
+ ;
+
+structName
+ : IDENTIFIER
+ ;
+
+declStatement
+ : 'int' IDENTIFIER '=' expression ';'
+ | structName ('?')? IDENTIFIER '=' expression ';'
+ ;
+
+returnStatement
+ : 'return' expression ';'
+ ;
+
+expression
+ : comparisonExpression
+ ;
+
+comparisonExpression
+ : additiveExpression (('==' | '!='| '>'| '<'| '>='| '<=') additiveExpression)*
+ ;
+
+additiveExpression
+ : multiplicativeExpression (('+' | '-') multiplicativeExpression)*
+ ;
+
+multiplicativeExpression
+ : unaryExpression (('*' | '/') unaryExpression)*
+ ;
+
+unaryExpression
+ : ('-') unaryExpression
+ | '!' unaryExpression
+ | primaryExpression
+ ;
+
+newExpression
+ : 'new' IDENTIFIER
+ ;
+
+fieldExpression
+ : primaryExpresson '.' IDENTIFIER
+ ;
+
+primaryExpression
+ : IDENTIFIER
+ | INTEGER_LITERAL
+ | 'true'
+ | 'false'
+ | 'null'
+ | newExpression
+ | '(' expression ')'
+ | fieldExpression
+ ;
+
+INTEGER_LITERAL
+ : [1-9][0-9]*
+ | [0]
+ ;
+
+IDENTIFIER
+ : NON_DIGIT (NON_DIGIT | DIGIT)*
+ ;
+
+NON_DIGIT: [a-zA-Z_];
+DEC_DIGIT: [0-9];
+```
diff --git a/docs/chapter10/Makefile b/docs/chapter10/Makefile
new file mode 100644
index 00000000..12659b8f
--- /dev/null
+++ b/docs/chapter10/Makefile
@@ -0,0 +1,12 @@
+GV := $(wildcard *.gv)
+SVG := $(patsubst %.gv,%.svg,$(GV))
+
+.PHONY: all
+all: $(SVG)
+
+%.svg: %.gv
+ dot -Tsvg $< > $@
+
+.PHONY: clean
+clean:
+ @rm -f $(SVG)
diff --git a/docs/chapter10/README.md b/docs/chapter10/README.md
new file mode 100644
index 00000000..32aec260
--- /dev/null
+++ b/docs/chapter10/README.md
@@ -0,0 +1,359 @@
+# Chapter 10: Structs and Memory
+
+
+# Table of Contents
+
+1. [Memory](#memory)
+2. [Alias Classes](#alias-classes)
+3. [Implementation of Alias Classes](#implementation-of-alias-classes)
+4. [Extensions to Intermediate Representation ](#extensions-to-intermediate-representation)
+5. [Enhanced Type Lattice](#enhanced-type-lattice)
+6. [Parser Enhancements](#parser-enhancements)
+7. [Null Pointer Analysis](#null-pointer-analysis)
+8. [Memory Operations Example](#memory-operations-example)
+9. [Additional Peephole Optimizations](#additional-peephole-optimizations)
+
+You can also read [this chapter](https://github.com/SeaOfNodes/Simple/tree/linear-chapter10) in a linear Git revision history on the [linear](https://github.com/SeaOfNodes/Simple/tree/linear) branch and [compare](https://github.com/SeaOfNodes/Simple/compare/linear-chapter09...linear-chapter10) it to the previous chapter.
+
+In this chapter:
+
+* We add user defined struct types in the Simple language.
+* We introduce the concept of Memory, Memory Pointers and Aliasing.
+* We add new nodes to represent operations on memory - such as creating new instance of a struct, storing and loading struct fields.
+
+Here is the [complete language grammar](10-grammar.md) for this chapter.
+
+
+## Memory
+
+In previous chapters, we dealt with scalar values that fit into a single
+machine register. We now introduce aggregate values of `struct` type; these
+have reference semantics and thus do not behave like register values, even if
+the struct would fit into a register. To support values of such a type, we
+need the concept of `Memory`.
+
+The core ideas regarding `Memory` are:
+
+* The program starts and stops with a single `Memory` value that encapsulates
+ the whole of available memory; `Start` produces memory and `Return` consumes
+ memory.
+
+* Each `struct` and field carves up this memory into "alias classes", a unique
+ class for each combination of struct and field.
+
+* Memory in different alias classes *never* aliases; memory in the same alias
+ class *always* aliases. This is sometimes called "equivalence class"
+ aliasing.
+
+* Equivalence class aliasing can be directly represented in the Sea of Nodes,
+ as such we will not use any other side-structure for aliasing. This also
+ means with normal peepholes we can do alias-based optimizations such as
+ load/store bypassing or load forwarding without needing to consult any side
+ structure, or make alias tracking modifications when we alter the graph.
+
+
+### Alias Classes
+
+Aliasing describes a situation in which a data location in memory can be
+accessed through multiple symbolic names (variables) in the program. Modifying
+the data through one name implicitly modifies the values associated with all
+the aliased names.
+
+Data accesses to the same alias class (struct+field) are serialized as defined
+by the source program; data in other classes is allowed to be accessed in
+parallel.
+
+Simple, like Java, is a strongly typed language. Therefore, two variables that
+have incompatible types cannot possibly be names to the same location in
+memory. We can use type information to determine which symbols alias,
+i.e., potentially reference the same location in memory. We
+divide/slice all memory into disjoint alias classes.
+
+We implement the "alias class" as a unique integer ID assigned to each field in
+a struct, where distinct struct types have their own set of ids. Thus, every
+field in every struct type is a new alias class. In later chapters as we
+implement arrays and subtyping, our strategy for assigning alias classes will
+be enhanced.
+
+For background information and overview of type based alias analysis, please
+refer to the paper `Type Based Alias Analysis`.[^1] Our approach is a form of
+TBAA similar to the "FieldTypeDecl" algorithm described in the paper. We do
+not track aliasing by instance of a Struct type.
+
+
+### Implementation of Alias Classes
+
+For example, suppose we have declared two struct types like so:
+
+```
+struct Vec2D { int x; int y; }
+struct Vec3D { int x; int y; int z; }
+```
+
+Then we can imagine assigning following alias class IDs
+
+| Struct type | Field | Alias |
+| ----------- | ----- | ----- |
+| Vec2D | x | 1 |
+| Vec2D | y | 2 |
+| Vec3D | x | 3 |
+| Vec3D | y | 4 |
+| Vec3D | z | 5 |
+
+So at this point we have sliced memory into 5 distinct alias classes.
+Note that the `x` and `y` in `Vec2D` do not alias `x` and `y` in `Vec3D`.
+
+In this chapter we do not have inheritance or sub-typing. But if we had subtyping and `Vec3D`
+was a subtype of `Vec2D` then `x` and `y` would alias and would be given the same alias class.
+
+## Extensions to Intermediate Representation
+
+We add following new Node types to support memory operations:
+
+| Node Name | Type | Description | Inputs | Value |
+|-----------|------|----------------------------------|-----------------------------------------------------------|----------------------------------------|
+| New | Mem | Create ptr to new object | Control, Struct type | Ptr value |
+| Store | Mem | Stores a value in a struct field | Memory slice (aliased by struct+field), Ptr, Field, Value | Memory slice (aliased by struct+field) |
+| Load | Mem | Loads a value from a field | Memory slice (aliased by struct+field), Ptr, Field | Value loaded |
+| Cast | Data | Upcasts a value | Control, Data, type | Upcast value |
+
+
+* New takes the current control as an input so that it is pinned correctly in
+ the control flow. Conceptually the control input is also a proxy for all
+ memory that originates from the Start node.
+
+* Above, "Ptr" refers to the base address of the allocated object. Ptrs can represent different values in loops.
+* A "Memory Slice" represents a slice of memory where all stores and loads alias. Different slices do not alias.
+
+Additionally, the following Node types will be enhanced:
+
+| Node Name | Type | Changes |
+|-----------|---------|------------------------------------------------------------------|
+| Start | Control | Start will produce the initial Memory projections, one per slice |
+| Return | Control | Will merge all memory slices |
+
+
+## Enhanced Type Lattice
+
+The Type Lattice for Simple has a major revision in this chapter.
+
+![Graph1](./lattice.svg)
+
+Within the Type Lattice, we now have the following type domains:
+
+* <font style="background-color:yellow">Control type</font> - represents control flow
+* <font style="background-color:lightblue">Integer type</font> - Integer values, with a Top, Bottom and constants
+* <font style="background-color:green" color="white">Pointer type</font> (new) - Represents a pointer to a struct type
+ * We use the prefix `*` to mean pointer-to. Thus `*S1` means pointer to
+ `S1`, `*$TOP` means pointer to `$TOP`.
+ * `?` suffix represents the union of a pointer to some type and `null`.
+ * The pointer lattice has only 2 entries: null or not-null. In both cases a struct lattice element is
+ included, and can be any member of the struct lattice.
+ * `null` is a pointer to non-existent memory object, i.e. `*$TOP?`, and is a
+ nullable. Notice that the null part of the type is low in the lattice,
+ while the struct part is the highest struct.
+ * `*void` is a synonym for `*$BOT` - i.e. it represents a non-null pointer to
+ all possible struct types, akin to `void *` in C except not null. It is
+ the inverse or *dual* of `null`, and the null part is high in the pointer
+ lattice, while the struct part is the lowest struct.
+ * `null` pointer evaluates to False and non-null pointers evaluate to True, as in C.
+
+* <font style="background-color:lightgreen">Struct type</font> (new) -
+ Represents user defined struct types, a struct type is allowed to have
+ members of Integer type only in this chapter, later chapters will expand
+ this.
+ * `⊤:struct` represents local Top for struct type; all we know about the type
+ is that it is a struct but, we do not know if it is a specific struct, or
+ all possible structs. In the code, we use a struct with no fields named `$TOP`.
+ * `⊥:struct` represents local Bottom for struct type; we definitely know the
+ value can take all possible struct types. In the code, we uise a struct
+ with no fields named `$BOT`.
+* <font style="background-color:blue" color="white">Memory type</font> (new) - Represents memory and memory slices
+ * `⊤:mem` - Nothing known about a slice; in the code we use `MEM#TOP`.
+ * `#n` - refers to a memory slice, and `n` is the alias class.
+ * `⊥:mem` - all of memory; in the code we use `MEM#BOT`.
+* <font style="background-color:pink">Tuple type</font> - when a Node results in a collection of values
+
+We make use of following operations on the lattice.
+
+* The `meet` operation takes two types and computes the greatest lower bound
+ type. While not true for all lattices, in the our lattice this can be
+ thought of as set union (ORing) of its input types (as sets).
+ * Example, meet of `*S1` and `*S2` results in `*void` - there is no lattice
+ element for exactly both `{*S1,*S2}`, so we drop down to the nearest
+ element containing both (and maybe more), which is `*void`.
+ * Meet of `*S1` and pointer `null` results in `*S1?`
+ * Meet of `*void` and `null` results in `*$BOT?`; bear in mind that `*void` is a synonym for `*$BOT`.
+ * Meet of `1` and `2` results in `Int Bot`.
+ * Meet of `#1` and `#2` results in `MEM#BOT`.
+* The `dual` operation is symmetric across the lattice centerline. Types directly on the centerline are their own dual.
+ * Find the corresponding node of the lattice after inverting the lattice.
+ * Thus, dual of `Top` is `Bot`.
+ * The dual of `*$TOP` is `*$BOT?`.
+ * For structs, the dual is obtained by computing the dual of each struct
+ member. Thus, dual of `*S1` is not `*S1?`, it is some `*S1?` with dualed
+ fields.
+
+* The `join` operation takes two types and computes the least upper bound type.
+ Similar to `meet` this can thought of as set intersection (ANDing) of its input types.
+ Because our lattice structure is symmetric and complete, we compute `join` with a well known identity:
+ `JOIN(x,y) === MEET(x.dual,y.dual).dual`
+ * Example, join of `*S1` and `*S2` results in `*$TOP`.
+ * Join of `1` and `2` results in `Int Top`.
+ * Join of `*void` and `Null` results in `*$TOP`.
+
+As we construct the Sea of Nodes graph, we ensure that values stay inside the
+domain they are created in - that is ptr fields will never contain ints
+(obviously)... nor even the generic `TOP` and `BOT`. There are a couple of
+nuances worth highlighting.
+
+* When Phis are created, the initial type of the Phi is based on the declared
+ type of its first input. This is a pessimistic type assignment because we do
+ not yet know what other types will be met.
+
+* When all the inputs of the Phi are known, we start with the local Top of the
+ declared type, and then compute a meet of all the input types. This
+ computation results in a more refined type for the Phi.
+
+## Parser Enhancements
+
+In previous chapters the only available type was Integer. Now, variables can
+be of Integer type or pointer to Struct types. To support this, the Parser now
+tracks the declared type of a variable (used to only be Integer!). The
+declared type of a variable defines the set of values that can be legitimately
+assigned to the variable. The Sea of Nodes graph also tracks the actual type
+of values assigned to variables, these type transitions are defined by the Type
+lattice described in the previous section.
+
+## Null Pointer Analysis
+
+The Simple language syntax allows a pointer variable to be specified as
+null-able - and it prevents ever throwing a Null Pointer Exception. The
+compiler decides if a null check is needed, and if needed and missing
+the compiler rejects the program (asking the user to insert a null check).
+
+When the Parser encounters conditions that test the truthiness of a pointer variable, it uses this knowledge to refine the type information in the branches that follow.
+
+Here are two motivating examples:
+
+```java
+struct Bar { int a; }
+Bar? bar = new Bar;
+if (arg) bar = null;
+if( bar ) bar.a = 1;
+```
+
+If `bar` is not `null` above, then we would like to allow the assignment to
+`bar.a`. If the final line lacked the null check, e.g. a plain `bar.a = 1;`,
+then `Java` would compile this program but throw a NPE, and Simple rejects the
+program pointing out a null check is required.
+
+
+```java
+struct Bar { int a; }
+Bar? bar = new Bar;
+if (arg) bar = null;
+int rez = 3;
+if( !bar ) rez=4;
+else bar.a = 1;
+```
+
+If `bar` is `null` then we would like `!bar` to evaluate to `true`. In the else
+branch we know `bar` is not null, hence the assignment to `bar.a` should be
+allowed.
+
+To enable this behaviour, we make following enhancements.
+
+* We track the null-ness of a pointer in the Type system, and hence in every
+ Node that ptr type flows through.
+
+* We "wrap" the predicate of an `If` node with an up-cast when we see that the
+ predicate is a ptr value. The up-cast removes the null possibility on the
+ true branch making it legal to use the pointer.
+
+* The up-cast is done using a `Cast` op with the type `*void`. This does a
+ lattice JOIN of the original type and `*void`. This JOIN operation preserves
+ everything we already know about ptr, and also adds the new knowledge that
+ the ptr is not-null.
+
+* The up-cast is represented by the `CastNode` op, and if applicable, we
+ replace all occurrences of the original predicate with the up-cast in the
+ current scope. The change is local to each branch of the `If`; occuring
+ separately for the true and the false branches of the `If` (and the false
+ branch inverts the predicate).
+
+* The up-cast peepholes normally; if its input's type is a super type of the
+ up-cast, then the `CastNode` can be removed. See `ScopeNode.upcast()` method,
+ and `CastNode`.
+
+* When computing a type for Not, we produce an Integer type when its input is a
+ ptr. When the input is a `null` we convert to `1` and when is a not `null`
+ ptr value, we convert to `0`. See `NotNode.compute()`.
+
+## Memory Operations Example
+
+This is a simple example illustrating how loads and stores are ordered based on aliasing.
+
+```java
+struct Vec2D { int x; int y; }
+
+Vec2D v = new Vec2D;
+v.x = 1;
+if (arg)
+ v.y = 2;
+else
+ v.y = 3;
+return v;
+```
+
+The graph from above will have the shape:
+
+![Graph1](./example1.svg)
+
+The graph visual has the following enhancements:
+
+* The memory edges are shown in green and blue.
+* The green edges occur on New nodes and anchor the ptr to a control flow node.
+* The blue edges show the threading of a memory op via the equivalence aliasing.
+
+## Additional Peephole Optimizations
+
+The equivalence aliasing makes it possible to optimize following scenarios:
+
+* Store followed by another Store to the same field inside an object; the first Store is redundant if there are no other references to the first Store
+* Load followed by a Store to a field inside an Object; the Load can be eliminated and the input value of the Store passed through.
+
+Both of these examples are illustrated in the example below:
+
+```java
+struct Bar {
+ int a;
+ int b;
+}
+struct Foo {
+ int x;
+}
+Foo? foo = null;
+Bar bar = new Bar;
+bar.a = 1;
+bar.a = 2;
+return bar.a;
+```
+
+Before the peephole optimizations, we get:
+
+![Graph2a](./example2a.svg)
+
+After enabling Store-Store peephole we get:
+
+![Graph2b](./example2b.svg)
+
+After load-after-store elision:
+
+![Graph2c](./example2c.svg)
+
+Note that at this stage the `bar` object is dead therefore the allocation of bar can be dropped.
+
+
+[^1]: Diwan A., McKinley K.S., Moss J.E.B. (1998).
+ Type Based Alias Analysis.
diff --git a/docs/chapter10/example1.gv b/docs/chapter10/example1.gv
new file mode 100644
index 00000000..cbb12cb5
--- /dev/null
+++ b/docs/chapter10/example1.gv
@@ -0,0 +1,78 @@
+digraph chapter10 {
+/*
+struct Vector2D { int x; int y; }
+Vector2D v = new Vector2D;
+v.x = 1;
+if (arg)
+ v.y = 2;
+else
+ v.y = 3;
+return v;
+
+*/
+ rankdir=BT;
+ concentrate="true";
+ compound="true";
+ subgraph cluster_Nodes {
+ Start2 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">Start</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">$ctrl</TD><TD PORT="p1">arg</TD><TD PORT="p2">$2</TD><TD PORT="p3">$3</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Stop3 [ shape=box style=filled fillcolor=yellow label="Stop" ];
+ new8 [ label="new Vector2D" ];
+ Con_9 [ label="#0" ];
+ Store11 [ label=".y =" ];
+ Con_12 [ label="#1" ];
+ Store13 [ label=".x =" ];
+ If14 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">If</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">True</TD><TD PORT="p1" BGCOLOR="yellow">False</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Con_18 [ label="#2" ];
+ Store19 [ label=".y =" ];
+ Con_22 [ label="#3" ];
+ Store23 [ label=".y =" ];
+ Region24 [ shape=box style=filled fillcolor=yellow label="Region" ];
+ Phi_326 [ style=filled fillcolor=lightyellow label="&phi;_$3" ];
+ Return27 [ shape=box style=filled fillcolor=yellow label="Return" ];
+ { rank=same; Region24;Phi_326;}
+ }
+ edge [ fontname=Helvetica, fontsize=8 ];
+ Stop3 -> Return27[taillabel=0 color=red];
+ new8 -> Start2:p0[taillabel=0 color=green];
+ Store11 -> Start2:p3[taillabel=1 color=blue];
+ Store11 -> new8[taillabel=2];
+ Store11 -> Con_9[taillabel=3];
+ Store13 -> Start2:p2[taillabel=1 color=blue];
+ Store13 -> new8[taillabel=2];
+ Store13 -> Con_12[taillabel=3];
+ If14 -> Start2:p0[taillabel=0 color=red];
+ If14 -> Start2:p1[taillabel=1];
+ Store19 -> Store11[taillabel=1 color=blue];
+ Store19 -> new8[taillabel=2];
+ Store19 -> Con_18[taillabel=3];
+ Store23 -> Store11[taillabel=1 color=blue];
+ Store23 -> new8[taillabel=2];
+ Store23 -> Con_22[taillabel=3];
+ Region24 -> If14:p0[taillabel=1 color=red];
+ Region24 -> If14:p1[taillabel=2 color=red];
+ Phi_326 -> Region24 [style=dotted taillabel=0];
+ Phi_326 -> Store19[taillabel=1 color=blue];
+ Phi_326 -> Store23[taillabel=2 color=blue constraint=false];
+ Return27 -> Region24[taillabel=0 color=red];
+ Return27 -> new8[taillabel=1];
+ Return27 -> Store13[taillabel=2 color=blue];
+ Return27 -> Phi_326[taillabel=3 color=blue];
+}
diff --git a/docs/chapter10/example1.svg b/docs/chapter10/example1.svg
new file mode 100644
index 00000000..6f493e7e
--- /dev/null
+++ b/docs/chapter10/example1.svg
@@ -0,0 +1,294 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
+ "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<!-- Generated by graphviz version 2.43.0 (0)
+ -->
+<!-- Title: chapter10 Pages: 1 -->
+<svg width="394pt" height="564pt"
+ viewBox="0.00 0.00 394.00 564.00" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+<g id="graph0" class="graph" transform="scale(1 1) rotate(0) translate(4 560)">
+<title>chapter10</title>
+<polygon fill="white" stroke="transparent" points="-4,4 -4,-560 390,-560 390,4 -4,4"/>
+<g id="clust1" class="cluster">
+<title>cluster_Nodes</title>
+<polygon fill="none" stroke="black" points="8,-8 8,-548 378,-548 378,-8 8,-8"/>
+</g>
+<!-- Start2 -->
+<g id="node1" class="node">
+<title>Start2</title>
+<polygon fill="yellow" stroke="transparent" points="25,-511 25,-536 156,-536 156,-511 25,-511"/>
+<polygon fill="none" stroke="black" points="25,-511 25,-536 156,-536 156,-511 25,-511"/>
+<text text-anchor="start" x="72" y="-519.8" font-family="Times,serif" font-size="14.00">Start</text>
+<polygon fill="none" stroke="black" points="25,-480 25,-511 156,-511 156,-480 25,-480"/>
+<polygon fill="yellow" stroke="transparent" points="30,-485 30,-506 70,-506 70,-485 30,-485"/>
+<polygon fill="none" stroke="black" points="30,-485 30,-506 70,-506 70,-485 30,-485"/>
+<text text-anchor="start" x="33" y="-491.8" font-family="Times,serif" font-size="14.00">$ctrl</text>
+<polygon fill="none" stroke="black" points="70,-485 70,-506 101,-506 101,-485 70,-485"/>
+<text text-anchor="start" x="73" y="-491.8" font-family="Times,serif" font-size="14.00">arg</text>
+<polygon fill="none" stroke="black" points="101,-485 101,-506 126,-506 126,-485 101,-485"/>
+<text text-anchor="start" x="104" y="-491.8" font-family="Times,serif" font-size="14.00">$2</text>
+<polygon fill="none" stroke="black" points="126,-485 126,-506 151,-506 151,-485 126,-485"/>
+<text text-anchor="start" x="129" y="-491.8" font-family="Times,serif" font-size="14.00">$3</text>
+</g>
+<!-- Stop3 -->
+<g id="node2" class="node">
+<title>Stop3</title>
+<polygon fill="yellow" stroke="black" points="201,-52 147,-52 147,-16 201,-16 201,-52"/>
+<text text-anchor="middle" x="174" y="-30.3" font-family="Times,serif" font-size="14.00">Stop</text>
+</g>
+<!-- Return27 -->
+<g id="node15" class="node">
+<title>Return27</title>
+<polygon fill="yellow" stroke="black" points="207,-124 141,-124 141,-88 207,-88 207,-124"/>
+<text text-anchor="middle" x="174" y="-102.3" font-family="Times,serif" font-size="14.00">Return</text>
+</g>
+<!-- Stop3&#45;&gt;Return27 -->
+<g id="edge1" class="edge">
+<title>Stop3&#45;&gt;Return27</title>
+<path fill="none" stroke="red" d="M174,-52.3C174,-60.02 174,-69.29 174,-77.89"/>
+<polygon fill="red" stroke="red" points="170.5,-77.9 174,-87.9 177.5,-77.9 170.5,-77.9"/>
+<text text-anchor="middle" x="171" y="-54.9" font-family="Helvetica,sans-Serif" font-size="8.00">0</text>
+</g>
+<!-- new8 -->
+<g id="node3" class="node">
+<title>new8</title>
+<ellipse fill="none" stroke="black" cx="203" cy="-422" rx="75.29" ry="18"/>
+<text text-anchor="middle" x="203" y="-418.3" font-family="Times,serif" font-size="14.00">new Vector2D</text>
+</g>
+<!-- new8&#45;&gt;Start2 -->
+<g id="edge2" class="edge">
+<title>new8&#45;&gt;Start2:p0</title>
+<path fill="none" stroke="green" d="M147.76,-434.26C110.79,-443.18 66.61,-456.99 53.71,-474.14"/>
+<polygon fill="green" stroke="green" points="50.24,-473.41 50,-484 56.79,-475.87 50.24,-473.41"/>
+<text text-anchor="middle" x="144.76" y="-436.86" font-family="Helvetica,sans-Serif" font-size="8.00">0</text>
+</g>
+<!-- Con_9 -->
+<g id="node4" class="node">
+<title>Con_9</title>
+<ellipse fill="none" stroke="black" cx="63" cy="-422" rx="27" ry="18"/>
+<text text-anchor="middle" x="63" y="-418.3" font-family="Times,serif" font-size="14.00">#0</text>
+</g>
+<!-- Store11 -->
+<g id="node5" class="node">
+<title>Store11</title>
+<ellipse fill="none" stroke="black" cx="170" cy="-350" rx="29.8" ry="18"/>
+<text text-anchor="middle" x="170" y="-346.3" font-family="Times,serif" font-size="14.00">.y =</text>
+</g>
+<!-- Store11&#45;&gt;Start2 -->
+<g id="edge3" class="edge">
+<title>Store11&#45;&gt;Start2:p3</title>
+<path fill="none" stroke="blue" d="M151.42,-364.19C139.69,-373.74 125.54,-387.77 119,-404 113.02,-418.84 115.61,-424.36 119,-440 122.69,-457.06 133.59,-461.26 137.54,-473.76"/>
+<polygon fill="blue" stroke="blue" points="134.13,-474.59 139,-484 141.06,-473.61 134.13,-474.59"/>
+<text text-anchor="middle" x="148.42" y="-366.79" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- Store11&#45;&gt;new8 -->
+<g id="edge4" class="edge">
+<title>Store11&#45;&gt;new8</title>
+<path fill="none" stroke="black" d="M177.82,-367.59C181.67,-375.75 186.4,-385.78 190.71,-394.93"/>
+<polygon fill="black" stroke="black" points="187.58,-396.49 195.01,-404.04 193.91,-393.51 187.58,-396.49"/>
+<text text-anchor="middle" x="174.82" y="-370.19" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Store11&#45;&gt;Con_9 -->
+<g id="edge5" class="edge">
+<title>Store11&#45;&gt;Con_9</title>
+<path fill="none" stroke="black" d="M150.37,-363.84C133.5,-374.88 108.99,-390.92 90.22,-403.2"/>
+<polygon fill="black" stroke="black" points="88.24,-400.31 81.78,-408.71 92.07,-406.17 88.24,-400.31"/>
+<text text-anchor="middle" x="153.37" y="-366.44" font-family="Helvetica,sans-Serif" font-size="8.00">3</text>
+</g>
+<!-- Con_12 -->
+<g id="node6" class="node">
+<title>Con_12</title>
+<ellipse fill="none" stroke="black" cx="323" cy="-422" rx="27" ry="18"/>
+<text text-anchor="middle" x="323" y="-418.3" font-family="Times,serif" font-size="14.00">#1</text>
+</g>
+<!-- Store13 -->
+<g id="node7" class="node">
+<title>Store13</title>
+<ellipse fill="none" stroke="black" cx="340" cy="-350" rx="29.8" ry="18"/>
+<text text-anchor="middle" x="340" y="-346.3" font-family="Times,serif" font-size="14.00">.x =</text>
+</g>
+<!-- Store13&#45;&gt;Start2 -->
+<g id="edge6" class="edge">
+<title>Store13&#45;&gt;Start2:p2</title>
+<path fill="none" stroke="blue" d="M350.63,-367.07C362.03,-386.53 376.33,-419.28 359,-440 290.38,-522.04 125.44,-383.17 114.57,-473.83"/>
+<polygon fill="blue" stroke="blue" points="111.06,-473.82 114,-484 118.05,-474.21 111.06,-473.82"/>
+<text text-anchor="middle" x="347.63" y="-369.67" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- Store13&#45;&gt;new8 -->
+<g id="edge7" class="edge">
+<title>Store13&#45;&gt;new8</title>
+<path fill="none" stroke="black" d="M317.99,-362.25C297.67,-372.63 267.01,-388.3 242.46,-400.84"/>
+<polygon fill="black" stroke="black" points="240.69,-397.81 233.38,-405.48 243.88,-404.04 240.69,-397.81"/>
+<text text-anchor="middle" x="314.99" y="-364.85" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Store13&#45;&gt;Con_12 -->
+<g id="edge8" class="edge">
+<title>Store13&#45;&gt;Con_12</title>
+<path fill="none" stroke="black" d="M335.88,-367.95C333.99,-375.74 331.7,-385.18 329.58,-393.92"/>
+<polygon fill="black" stroke="black" points="326.15,-393.18 327.2,-403.72 332.96,-394.83 326.15,-393.18"/>
+<text text-anchor="middle" x="332.88" y="-370.55" font-family="Helvetica,sans-Serif" font-size="8.00">3</text>
+</g>
+<!-- If14 -->
+<g id="node8" class="node">
+<title>If14</title>
+<polygon fill="yellow" stroke="transparent" points="24,-267 24,-292 118,-292 118,-267 24,-267"/>
+<polygon fill="none" stroke="black" points="24,-267 24,-292 118,-292 118,-267 24,-267"/>
+<text text-anchor="start" x="65.5" y="-275.8" font-family="Times,serif" font-size="14.00">If</text>
+<polygon fill="none" stroke="black" points="24,-236 24,-267 118,-267 118,-236 24,-236"/>
+<polygon fill="yellow" stroke="transparent" points="29,-241 29,-262 69,-262 69,-241 29,-241"/>
+<polygon fill="none" stroke="black" points="29,-241 29,-262 69,-262 69,-241 29,-241"/>
+<text text-anchor="start" x="32" y="-247.8" font-family="Times,serif" font-size="14.00">True</text>
+<polygon fill="yellow" stroke="transparent" points="69,-241 69,-262 113,-262 113,-241 69,-241"/>
+<polygon fill="none" stroke="black" points="69,-241 69,-262 113,-262 113,-241 69,-241"/>
+<text text-anchor="start" x="72" y="-247.8" font-family="Times,serif" font-size="14.00">False</text>
+</g>
+<!-- If14&#45;&gt;Start2 -->
+<g id="edge9" class="edge">
+<title>If14&#45;&gt;Start2:p0</title>
+<path fill="none" stroke="red" d="M58.13,-296.08C47.38,-323.83 32.89,-365.85 27,-404 24.56,-419.81 23.18,-424.46 27,-440 31.32,-457.58 44.03,-461.08 48.46,-473.95"/>
+<polygon fill="red" stroke="red" points="45.02,-474.65 50,-484 51.94,-473.58 45.02,-474.65"/>
+<text text-anchor="middle" x="55.13" y="-298.68" font-family="Helvetica,sans-Serif" font-size="8.00">0</text>
+</g>
+<!-- Con_18 -->
+<g id="node9" class="node">
+<title>Con_18</title>
+<ellipse fill="none" stroke="black" cx="95" cy="-350" rx="27" ry="18"/>
+<text text-anchor="middle" x="95" y="-346.3" font-family="Times,serif" font-size="14.00">#2</text>
+</g>
+<!-- Store19 -->
+<g id="node10" class="node">
+<title>Store19</title>
+<ellipse fill="none" stroke="black" cx="174" cy="-264" rx="29.8" ry="18"/>
+<text text-anchor="middle" x="174" y="-260.3" font-family="Times,serif" font-size="14.00">.y =</text>
+</g>
+<!-- Store19&#45;&gt;new8 -->
+<g id="edge12" class="edge">
+<title>Store19&#45;&gt;new8</title>
+<path fill="none" stroke="black" d="M188.91,-279.62C203.35,-295.52 222.56,-322.27 219,-349"/>
+<path fill="none" stroke="black" d="M219,-351C217.08,-365.43 213.58,-381.26 210.34,-394.21"/>
+<polygon fill="black" stroke="black" points="206.95,-393.34 207.84,-403.9 213.73,-395.09 206.95,-393.34"/>
+<text text-anchor="middle" x="185.91" y="-282.22" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Store19&#45;&gt;Store11 -->
+<g id="edge11" class="edge">
+<title>Store19&#45;&gt;Store11</title>
+<path fill="none" stroke="blue" d="M173.19,-282C172.65,-293.31 171.93,-308.42 171.31,-321.43"/>
+<polygon fill="blue" stroke="blue" points="167.8,-321.58 170.82,-331.74 174.79,-321.92 167.8,-321.58"/>
+<text text-anchor="middle" x="170.19" y="-284.6" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- Store19&#45;&gt;Con_18 -->
+<g id="edge13" class="edge">
+<title>Store19&#45;&gt;Con_18</title>
+<path fill="none" stroke="black" d="M159.88,-280.02C147.56,-293.12 129.52,-312.29 115.59,-327.1"/>
+<polygon fill="black" stroke="black" points="113.04,-324.71 108.74,-334.39 118.14,-329.51 113.04,-324.71"/>
+<text text-anchor="middle" x="156.88" y="-282.62" font-family="Helvetica,sans-Serif" font-size="8.00">3</text>
+</g>
+<!-- Con_22 -->
+<g id="node11" class="node">
+<title>Con_22</title>
+<ellipse fill="none" stroke="black" cx="265" cy="-350" rx="27" ry="18"/>
+<text text-anchor="middle" x="265" y="-346.3" font-family="Times,serif" font-size="14.00">#3</text>
+</g>
+<!-- Store23 -->
+<g id="node12" class="node">
+<title>Store23</title>
+<ellipse fill="none" stroke="black" cx="272" cy="-264" rx="29.8" ry="18"/>
+<text text-anchor="middle" x="272" y="-260.3" font-family="Times,serif" font-size="14.00">.y =</text>
+</g>
+<!-- Store23&#45;&gt;new8 -->
+<g id="edge15" class="edge">
+<title>Store23&#45;&gt;new8</title>
+<path fill="none" stroke="black" d="M257.04,-279.75C242.69,-295.35 222.67,-321.48 219,-349"/>
+<text text-anchor="middle" x="254.04" y="-282.35" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Store23&#45;&gt;Store11 -->
+<g id="edge14" class="edge">
+<title>Store23&#45;&gt;Store11</title>
+<path fill="none" stroke="blue" d="M254.7,-279.25C238.26,-292.79 213.37,-313.28 194.82,-328.56"/>
+<polygon fill="blue" stroke="blue" points="192.54,-325.9 187.05,-334.96 196.99,-331.31 192.54,-325.9"/>
+<text text-anchor="middle" x="251.7" y="-272.85" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- Store23&#45;&gt;Con_22 -->
+<g id="edge16" class="edge">
+<title>Store23&#45;&gt;Con_22</title>
+<path fill="none" stroke="black" d="M270.58,-282C269.64,-293.31 268.38,-308.42 267.3,-321.43"/>
+<polygon fill="black" stroke="black" points="263.78,-321.48 266.44,-331.74 270.76,-322.06 263.78,-321.48"/>
+<text text-anchor="middle" x="267.58" y="-284.6" font-family="Helvetica,sans-Serif" font-size="8.00">3</text>
+</g>
+<!-- Region24 -->
+<g id="node13" class="node">
+<title>Region24</title>
+<polygon fill="yellow" stroke="black" points="123,-196 57,-196 57,-160 123,-160 123,-196"/>
+<text text-anchor="middle" x="90" y="-174.3" font-family="Times,serif" font-size="14.00">Region</text>
+</g>
+<!-- Region24&#45;&gt;If14 -->
+<g id="edge17" class="edge">
+<title>Region24&#45;&gt;If14:p0</title>
+<path fill="none" stroke="red" d="M70.46,-196.22C62.05,-205.18 53.41,-216.97 50.26,-229.91"/>
+<polygon fill="red" stroke="red" points="46.76,-229.64 49,-240 53.71,-230.51 46.76,-229.64"/>
+<text text-anchor="middle" x="67.46" y="-198.82" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- Region24&#45;&gt;If14 -->
+<g id="edge18" class="edge">
+<title>Region24&#45;&gt;If14:p1</title>
+<path fill="none" stroke="red" d="M90.43,-196.09C90.64,-205.55 90.87,-217.77 90.96,-229.69"/>
+<polygon fill="red" stroke="red" points="87.46,-230.01 91,-240 94.46,-229.99 87.46,-230.01"/>
+<text text-anchor="middle" x="87.43" y="-198.69" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Phi_326 -->
+<g id="node14" class="node">
+<title>Phi_326</title>
+<ellipse fill="lightyellow" stroke="black" cx="174" cy="-178" rx="33.29" ry="18"/>
+<text text-anchor="middle" x="174" y="-174.3" font-family="Times,serif" font-size="14.00">φ_$3</text>
+</g>
+<!-- Phi_326&#45;&gt;Store19 -->
+<g id="edge20" class="edge">
+<title>Phi_326&#45;&gt;Store19</title>
+<path fill="none" stroke="blue" d="M174,-196.4C174,-207.74 174,-222.77 174,-235.68"/>
+<polygon fill="blue" stroke="blue" points="170.5,-235.9 174,-245.9 177.5,-235.9 170.5,-235.9"/>
+<text text-anchor="middle" x="171" y="-199" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- Phi_326&#45;&gt;Store23 -->
+<g id="edge21" class="edge">
+<title>Phi_326&#45;&gt;Store23</title>
+<path fill="none" stroke="blue" d="M191.07,-193.63C206.76,-207.08 230.2,-227.17 247.81,-242.27"/>
+<polygon fill="blue" stroke="blue" points="245.58,-244.97 255.45,-248.82 250.14,-239.65 245.58,-244.97"/>
+<text text-anchor="middle" x="188.07" y="-196.23" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Phi_326&#45;&gt;Region24 -->
+<g id="edge19" class="edge">
+<title>Phi_326&#45;&gt;Region24</title>
+<path fill="none" stroke="black" stroke-dasharray="1,5" d="M140.62,-178C138.17,-178 135.71,-178 133.25,-178"/>
+<polygon fill="black" stroke="black" points="133.14,-174.5 123.14,-178 133.14,-181.5 133.14,-174.5"/>
+<text text-anchor="middle" x="137.62" y="-171.6" font-family="Helvetica,sans-Serif" font-size="8.00">0</text>
+</g>
+<!-- Return27&#45;&gt;new8 -->
+<g id="edge23" class="edge">
+<title>Return27&#45;&gt;new8</title>
+<path fill="none" stroke="black" d="M207.48,-120.36C230.67,-131.64 259.67,-150.25 273,-177"/>
+<path fill="none" stroke="black" d="M273,-179C286.16,-205.41 244.02,-204.62 233,-232 213.44,-280.58 225.92,-297.09 219,-349"/>
+<text text-anchor="middle" x="210.48" y="-113.96" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- Return27&#45;&gt;Store13 -->
+<g id="edge24" class="edge">
+<title>Return27&#45;&gt;Store13</title>
+<path fill="none" stroke="blue" d="M273,-179C286,-204.9 298.85,-205.68 311,-232 324.45,-261.13 332.19,-297.33 336.24,-321.69"/>
+<polygon fill="blue" stroke="blue" points="332.79,-322.32 337.8,-331.66 339.71,-321.24 332.79,-322.32"/>
+<text text-anchor="middle" x="270" y="-172.6" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Return27&#45;&gt;Region24 -->
+<g id="edge22" class="edge">
+<title>Return27&#45;&gt;Region24</title>
+<path fill="none" stroke="red" d="M153.24,-124.3C142.76,-133.03 129.89,-143.76 118.5,-153.25"/>
+<polygon fill="red" stroke="red" points="115.97,-150.81 110.53,-159.9 120.45,-156.18 115.97,-150.81"/>
+<text text-anchor="middle" x="150.24" y="-126.9" font-family="Helvetica,sans-Serif" font-size="8.00">0</text>
+</g>
+<!-- Return27&#45;&gt;Phi_326 -->
+<g id="edge25" class="edge">
+<title>Return27&#45;&gt;Phi_326</title>
+<path fill="none" stroke="blue" d="M174,-124.3C174,-132.02 174,-141.29 174,-149.89"/>
+<polygon fill="blue" stroke="blue" points="170.5,-149.9 174,-159.9 177.5,-149.9 170.5,-149.9"/>
+<text text-anchor="middle" x="171" y="-126.9" font-family="Helvetica,sans-Serif" font-size="8.00">3</text>
+</g>
+</g>
+</svg>
diff --git a/docs/chapter10/example2a.gv b/docs/chapter10/example2a.gv
new file mode 100644
index 00000000..23f31bf8
--- /dev/null
+++ b/docs/chapter10/example2a.gv
@@ -0,0 +1,65 @@
+digraph chapter10 {
+/*
+struct Bar {
+ int a;
+ int b;
+}
+struct Foo {
+ int x;
+}
+Foo? foo = null;
+Bar bar = new Bar;
+bar.a = 1;
+bar.a = 2;
+return bar.a;
+
+*/
+ rankdir=BT;
+ concentrate="true";
+ compound="true";
+ subgraph cluster_Nodes {
+ Start2 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">Start</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">$ctrl</TD><TD PORT="p2">$2</TD><TD PORT="p3">$3</TD><TD PORT="p4">$4</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Stop3 [ shape=box style=filled fillcolor=yellow label="Stop" ];
+ new10 [ label="new Bar" ];
+ Con_11 [ label="#0" ];
+ Store12 [ label=".a =" ];
+ Store13 [ label=".b =" ];
+ Con_14 [ label="#1" ];
+ Store15 [ label=".a =" ];
+ Con_16 [ label="#2" ];
+ Store17 [ label=".a =" ];
+ Load18 [ label=".a" ];
+ Return19 [ shape=box style=filled fillcolor=yellow label="Return" ];
+ }
+ edge [ fontname=Helvetica, fontsize=8 ];
+ Stop3 -> Return19[taillabel=0 color=red];
+ new10 -> Start2:p0[taillabel=0 color=green];
+ Store12 -> Start2:p2[taillabel=1 color=blue];
+ Store12 -> new10[taillabel=2];
+ Store12 -> Con_11[taillabel=3];
+ Store13 -> Start2:p3[taillabel=1 color=blue];
+ Store13 -> new10[taillabel=2];
+ Store13 -> Con_11[taillabel=3];
+ Store15 -> Store12[taillabel=1 color=blue];
+ Store15 -> new10[taillabel=2];
+ Store15 -> Con_14[taillabel=3];
+ Store17 -> Store15[taillabel=1 color=blue];
+ Store17 -> new10[taillabel=2];
+ Store17 -> Con_16[taillabel=3];
+ Load18 -> Store17[taillabel=1 color=blue];
+ Load18 -> new10[taillabel=2];
+ Return19 -> Start2:p0[taillabel=0 color=red];
+ Return19 -> Load18[taillabel=1];
+ Return19 -> Store17[taillabel=2 color=blue];
+ Return19 -> Store13[taillabel=3 color=blue];
+ Return19 -> Start2:p4[taillabel=4 color=blue];
+}
diff --git a/docs/chapter10/example2a.svg b/docs/chapter10/example2a.svg
new file mode 100644
index 00000000..9f069ad4
--- /dev/null
+++ b/docs/chapter10/example2a.svg
@@ -0,0 +1,249 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
+ "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<!-- Generated by graphviz version 2.43.0 (0)
+ -->
+<!-- Title: chapter10 Pages: 1 -->
+<svg width="331pt" height="608pt"
+ viewBox="0.00 0.00 331.00 608.00" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+<g id="graph0" class="graph" transform="scale(1 1) rotate(0) translate(4 604)">
+<title>chapter10</title>
+<polygon fill="white" stroke="transparent" points="-4,4 -4,-604 327,-604 327,4 -4,4"/>
+<g id="clust1" class="cluster">
+<title>cluster_Nodes</title>
+<polygon fill="none" stroke="black" points="8,-8 8,-592 315,-592 315,-8 8,-8"/>
+</g>
+<!-- Start2 -->
+<g id="node1" class="node">
+<title>Start2</title>
+<polygon fill="yellow" stroke="transparent" points="129,-555 129,-580 254,-580 254,-555 129,-555"/>
+<polygon fill="none" stroke="black" points="129,-555 129,-580 254,-580 254,-555 129,-555"/>
+<text text-anchor="start" x="173" y="-563.8" font-family="Times,serif" font-size="14.00">Start</text>
+<polygon fill="none" stroke="black" points="129,-524 129,-555 254,-555 254,-524 129,-524"/>
+<polygon fill="yellow" stroke="transparent" points="134,-529 134,-550 174,-550 174,-529 134,-529"/>
+<polygon fill="none" stroke="black" points="134,-529 134,-550 174,-550 174,-529 134,-529"/>
+<text text-anchor="start" x="137" y="-535.8" font-family="Times,serif" font-size="14.00">$ctrl</text>
+<polygon fill="none" stroke="black" points="174,-529 174,-550 199,-550 199,-529 174,-529"/>
+<text text-anchor="start" x="177" y="-535.8" font-family="Times,serif" font-size="14.00">$2</text>
+<polygon fill="none" stroke="black" points="199,-529 199,-550 224,-550 224,-529 199,-529"/>
+<text text-anchor="start" x="202" y="-535.8" font-family="Times,serif" font-size="14.00">$3</text>
+<polygon fill="none" stroke="black" points="224,-529 224,-550 249,-550 249,-529 224,-529"/>
+<text text-anchor="start" x="227" y="-535.8" font-family="Times,serif" font-size="14.00">$4</text>
+</g>
+<!-- Stop3 -->
+<g id="node2" class="node">
+<title>Stop3</title>
+<polygon fill="yellow" stroke="black" points="101,-52 47,-52 47,-16 101,-16 101,-52"/>
+<text text-anchor="middle" x="74" y="-30.3" font-family="Times,serif" font-size="14.00">Stop</text>
+</g>
+<!-- Return19 -->
+<g id="node12" class="node">
+<title>Return19</title>
+<polygon fill="yellow" stroke="black" points="107,-124 41,-124 41,-88 107,-88 107,-124"/>
+<text text-anchor="middle" x="74" y="-102.3" font-family="Times,serif" font-size="14.00">Return</text>
+</g>
+<!-- Stop3&#45;&gt;Return19 -->
+<g id="edge1" class="edge">
+<title>Stop3&#45;&gt;Return19</title>
+<path fill="none" stroke="red" d="M74,-52.3C74,-60.02 74,-69.29 74,-77.89"/>
+<polygon fill="red" stroke="red" points="70.5,-77.9 74,-87.9 77.5,-77.9 70.5,-77.9"/>
+<text text-anchor="middle" x="71" y="-54.9" font-family="Helvetica,sans-Serif" font-size="8.00">0</text>
+</g>
+<!-- new10 -->
+<g id="node3" class="node">
+<title>new10</title>
+<ellipse fill="none" stroke="black" cx="118" cy="-466" rx="49.29" ry="18"/>
+<text text-anchor="middle" x="118" y="-462.3" font-family="Times,serif" font-size="14.00">new Bar</text>
+</g>
+<!-- new10&#45;&gt;Start2 -->
+<g id="edge2" class="edge">
+<title>new10&#45;&gt;Start2:p0</title>
+<path fill="none" stroke="green" d="M133.89,-483.12C141.58,-492.29 149.78,-504.57 152.8,-517.77"/>
+<polygon fill="green" stroke="green" points="149.36,-518.48 154,-528 156.31,-517.66 149.36,-518.48"/>
+<text text-anchor="middle" x="130.89" y="-485.72" font-family="Helvetica,sans-Serif" font-size="8.00">0</text>
+</g>
+<!-- Con_11 -->
+<g id="node4" class="node">
+<title>Con_11</title>
+<ellipse fill="none" stroke="black" cx="232" cy="-466" rx="27" ry="18"/>
+<text text-anchor="middle" x="232" y="-462.3" font-family="Times,serif" font-size="14.00">#0</text>
+</g>
+<!-- Store12 -->
+<g id="node5" class="node">
+<title>Store12</title>
+<ellipse fill="none" stroke="black" cx="178" cy="-394" rx="29.8" ry="18"/>
+<text text-anchor="middle" x="178" y="-390.3" font-family="Times,serif" font-size="14.00">.a =</text>
+</g>
+<!-- Store12&#45;&gt;Start2 -->
+<g id="edge3" class="edge">
+<title>Store12&#45;&gt;Start2:p2</title>
+<path fill="none" stroke="blue" d="M179.7,-412.2C181.85,-435.45 185.36,-478.51 185.92,-517.62"/>
+<polygon fill="blue" stroke="blue" points="182.43,-518.03 186,-528 189.43,-517.97 182.43,-518.03"/>
+<text text-anchor="middle" x="176.7" y="-414.8" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- Store12&#45;&gt;new10 -->
+<g id="edge4" class="edge">
+<title>Store12&#45;&gt;new10</title>
+<path fill="none" stroke="black" d="M164.68,-410.54C157.06,-419.43 147.32,-430.79 138.71,-440.84"/>
+<polygon fill="black" stroke="black" points="135.97,-438.66 132.11,-448.53 141.28,-443.22 135.97,-438.66"/>
+<text text-anchor="middle" x="161.68" y="-413.14" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Store12&#45;&gt;Con_11 -->
+<g id="edge5" class="edge">
+<title>Store12&#45;&gt;Con_11</title>
+<path fill="none" stroke="black" d="M189.98,-410.54C196.98,-419.6 205.94,-431.21 213.79,-441.39"/>
+<polygon fill="black" stroke="black" points="211.17,-443.73 220.05,-449.51 216.71,-439.45 211.17,-443.73"/>
+<text text-anchor="middle" x="186.98" y="-413.14" font-family="Helvetica,sans-Serif" font-size="8.00">3</text>
+</g>
+<!-- Store13 -->
+<g id="node6" class="node">
+<title>Store13</title>
+<ellipse fill="none" stroke="black" cx="256" cy="-394" rx="30.59" ry="18"/>
+<text text-anchor="middle" x="256" y="-390.3" font-family="Times,serif" font-size="14.00">.b =</text>
+</g>
+<!-- Store13&#45;&gt;Start2 -->
+<g id="edge6" class="edge">
+<title>Store13&#45;&gt;Start2:p3</title>
+<path fill="none" stroke="blue" d="M263.6,-411.63C270.91,-430.21 279.31,-460.72 268,-484 256,-508.69 222.7,-499.84 214.07,-517.7"/>
+<polygon fill="blue" stroke="blue" points="210.54,-517.51 212,-528 217.4,-518.88 210.54,-517.51"/>
+<text text-anchor="middle" x="260.6" y="-414.23" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- Store13&#45;&gt;new10 -->
+<g id="edge7" class="edge">
+<title>Store13&#45;&gt;new10</title>
+<path fill="none" stroke="black" d="M233.52,-406.4C212.26,-417.19 179.96,-433.57 154.91,-446.28"/>
+<polygon fill="black" stroke="black" points="153.04,-443.3 145.71,-450.95 156.21,-449.54 153.04,-443.3"/>
+<text text-anchor="middle" x="230.52" y="-409" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Store13&#45;&gt;Con_11 -->
+<g id="edge8" class="edge">
+<title>Store13&#45;&gt;Con_11</title>
+<path fill="none" stroke="black" d="M250.19,-411.95C247.45,-419.94 244.11,-429.67 241.05,-438.6"/>
+<polygon fill="black" stroke="black" points="237.69,-437.62 237.76,-448.21 244.31,-439.89 237.69,-437.62"/>
+<text text-anchor="middle" x="247.19" y="-414.55" font-family="Helvetica,sans-Serif" font-size="8.00">3</text>
+</g>
+<!-- Con_14 -->
+<g id="node7" class="node">
+<title>Con_14</title>
+<ellipse fill="none" stroke="black" cx="83" cy="-394" rx="27" ry="18"/>
+<text text-anchor="middle" x="83" y="-390.3" font-family="Times,serif" font-size="14.00">#1</text>
+</g>
+<!-- Store15 -->
+<g id="node8" class="node">
+<title>Store15</title>
+<ellipse fill="none" stroke="black" cx="86" cy="-322" rx="29.8" ry="18"/>
+<text text-anchor="middle" x="86" y="-318.3" font-family="Times,serif" font-size="14.00">.a =</text>
+</g>
+<!-- Store15&#45;&gt;new10 -->
+<g id="edge10" class="edge">
+<title>Store15&#45;&gt;new10</title>
+<path fill="none" stroke="black" d="M98.96,-338.58C106.42,-348.58 115.07,-362.24 119,-376 124.76,-396.15 124.14,-419.93 122.28,-437.84"/>
+<polygon fill="black" stroke="black" points="118.79,-437.53 121.04,-447.89 125.74,-438.39 118.79,-437.53"/>
+<text text-anchor="middle" x="95.96" y="-341.18" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Store15&#45;&gt;Store12 -->
+<g id="edge9" class="edge">
+<title>Store15&#45;&gt;Store12</title>
+<path fill="none" stroke="blue" d="M103.74,-336.5C117.4,-346.89 136.48,-361.41 151.88,-373.13"/>
+<polygon fill="blue" stroke="blue" points="149.92,-376.04 160,-379.31 154.16,-370.47 149.92,-376.04"/>
+<text text-anchor="middle" x="106.74" y="-339.1" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- Store15&#45;&gt;Con_14 -->
+<g id="edge11" class="edge">
+<title>Store15&#45;&gt;Con_14</title>
+<path fill="none" stroke="black" d="M85.26,-340.3C84.93,-348.02 84.53,-357.29 84.16,-365.89"/>
+<polygon fill="black" stroke="black" points="80.66,-365.75 83.73,-375.9 87.66,-366.05 80.66,-365.75"/>
+<text text-anchor="middle" x="82.26" y="-342.9" font-family="Helvetica,sans-Serif" font-size="8.00">3</text>
+</g>
+<!-- Con_16 -->
+<g id="node9" class="node">
+<title>Con_16</title>
+<ellipse fill="none" stroke="black" cx="161" cy="-322" rx="27" ry="18"/>
+<text text-anchor="middle" x="161" y="-318.3" font-family="Times,serif" font-size="14.00">#2</text>
+</g>
+<!-- Store17 -->
+<g id="node10" class="node">
+<title>Store17</title>
+<ellipse fill="none" stroke="black" cx="86" cy="-250" rx="29.8" ry="18"/>
+<text text-anchor="middle" x="86" y="-246.3" font-family="Times,serif" font-size="14.00">.a =</text>
+</g>
+<!-- Store17&#45;&gt;new10 -->
+<g id="edge13" class="edge">
+<title>Store17&#45;&gt;new10</title>
+<path fill="none" stroke="black" d="M70.13,-265.26C57.27,-278.25 40.68,-298.75 37,-321"/>
+<text text-anchor="middle" x="67.13" y="-267.86" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Store17&#45;&gt;Store15 -->
+<g id="edge12" class="edge">
+<title>Store17&#45;&gt;Store15</title>
+<path fill="none" stroke="blue" d="M86,-268.3C86,-276.02 86,-285.29 86,-293.89"/>
+<polygon fill="blue" stroke="blue" points="82.5,-293.9 86,-303.9 89.5,-293.9 82.5,-293.9"/>
+<text text-anchor="middle" x="83" y="-270.9" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- Store17&#45;&gt;Con_16 -->
+<g id="edge14" class="edge">
+<title>Store17&#45;&gt;Con_16</title>
+<path fill="none" stroke="black" d="M101.54,-265.5C112.24,-275.49 126.62,-288.91 138.56,-300.06"/>
+<polygon fill="black" stroke="black" points="136.29,-302.73 145.99,-306.99 141.07,-297.61 136.29,-302.73"/>
+<text text-anchor="middle" x="98.54" y="-268.1" font-family="Helvetica,sans-Serif" font-size="8.00">3</text>
+</g>
+<!-- Load18 -->
+<g id="node11" class="node">
+<title>Load18</title>
+<ellipse fill="none" stroke="black" cx="74" cy="-178" rx="27" ry="18"/>
+<text text-anchor="middle" x="74" y="-174.3" font-family="Times,serif" font-size="14.00">.a</text>
+</g>
+<!-- Load18&#45;&gt;new10 -->
+<g id="edge16" class="edge">
+<title>Load18&#45;&gt;new10</title>
+<path fill="none" stroke="black" d="M63.89,-195.07C57.97,-205.26 50.92,-218.94 47,-232 35.56,-270.12 43.5,-281.73 37,-321"/>
+<path fill="none" stroke="black" d="M37,-323C29.78,-362.14 27.2,-377.47 47,-412 54.9,-425.77 67.96,-437.05 80.75,-445.61"/>
+<polygon fill="black" stroke="black" points="79.16,-448.74 89.49,-451.1 82.88,-442.82 79.16,-448.74"/>
+<text text-anchor="middle" x="60.89" y="-197.67" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Load18&#45;&gt;Store17 -->
+<g id="edge15" class="edge">
+<title>Load18&#45;&gt;Store17</title>
+<path fill="none" stroke="blue" d="M76.9,-195.95C78.23,-203.65 79.82,-212.97 81.31,-221.64"/>
+<polygon fill="blue" stroke="blue" points="77.9,-222.46 83.04,-231.72 84.8,-221.28 77.9,-222.46"/>
+<text text-anchor="middle" x="73.9" y="-198.55" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- Return19&#45;&gt;Start2 -->
+<g id="edge17" class="edge">
+<title>Return19&#45;&gt;Start2:p0</title>
+<path fill="none" stroke="red" d="M59.94,-124.2C52.45,-134.13 43.64,-147.17 38,-160 21.64,-197.21 17,-208.36 17,-249 17,-249 17,-249 17,-395 17,-473.65 47.97,-533.65 122.67,-538.66"/>
+<polygon fill="red" stroke="red" points="122.89,-542.17 133,-539 123.12,-535.17 122.89,-542.17"/>
+<text text-anchor="middle" x="56.94" y="-126.8" font-family="Helvetica,sans-Serif" font-size="8.00">0</text>
+</g>
+<!-- Return19&#45;&gt;Start2 -->
+<g id="edge21" class="edge">
+<title>Return19&#45;&gt;Start2:p4</title>
+<path fill="none" stroke="blue" d="M306,-323C287.16,-411.95 339.16,-519.36 271.5,-536.61"/>
+<polygon fill="blue" stroke="blue" points="270.87,-533.17 261.65,-538.38 272.11,-540.06 270.87,-533.17"/>
+<text text-anchor="middle" x="303" y="-316.6" font-family="Helvetica,sans-Serif" font-size="8.00">4</text>
+</g>
+<!-- Return19&#45;&gt;Store13 -->
+<g id="edge20" class="edge">
+<title>Return19&#45;&gt;Store13</title>
+<path fill="none" stroke="blue" d="M306,-179C314.76,-241.5 316.5,-258.77 306,-321"/>
+<path fill="none" stroke="blue" d="M306,-323C302.13,-341.27 290.11,-358.39 278.83,-371.13"/>
+<polygon fill="blue" stroke="blue" points="276.24,-368.77 271.98,-378.47 281.36,-373.55 276.24,-368.77"/>
+<text text-anchor="middle" x="303" y="-172.6" font-family="Helvetica,sans-Serif" font-size="8.00">3</text>
+</g>
+<!-- Return19&#45;&gt;Store17 -->
+<g id="edge19" class="edge">
+<title>Return19&#45;&gt;Store17</title>
+<path fill="none" stroke="blue" d="M107.24,-110.22C170.02,-117.23 300.33,-136.59 306,-177"/>
+<path fill="none" stroke="blue" d="M306,-179C311.23,-216.32 190.09,-236.58 125.4,-244.71"/>
+<polygon fill="blue" stroke="blue" points="124.65,-241.27 115.15,-245.95 125.5,-248.22 124.65,-241.27"/>
+<text text-anchor="middle" x="110.24" y="-103.82" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Return19&#45;&gt;Load18 -->
+<g id="edge18" class="edge">
+<title>Return19&#45;&gt;Load18</title>
+<path fill="none" stroke="black" d="M74,-124.3C74,-132.02 74,-141.29 74,-149.89"/>
+<polygon fill="black" stroke="black" points="70.5,-149.9 74,-159.9 77.5,-149.9 70.5,-149.9"/>
+<text text-anchor="middle" x="71" y="-126.9" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+</g>
+</svg>
diff --git a/docs/chapter10/example2b.gv b/docs/chapter10/example2b.gv
new file mode 100644
index 00000000..d732e874
--- /dev/null
+++ b/docs/chapter10/example2b.gv
@@ -0,0 +1,56 @@
+digraph chapter10 {
+/*
+struct Bar {
+ int a;
+ int b;
+}
+struct Foo {
+ int x;
+}
+Foo? foo = null;
+Bar bar = new Bar;
+bar.a = 1;
+bar.a = 2;
+return bar.a;
+
+*/
+ rankdir=BT;
+ concentrate="true";
+ compound="true";
+ subgraph cluster_Nodes {
+ Start2 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">Start</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">$ctrl</TD><TD PORT="p2">$2</TD><TD PORT="p3">$3</TD><TD PORT="p4">$4</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Stop3 [ shape=box style=filled fillcolor=yellow label="Stop" ];
+ new10 [ label="new Bar" ];
+ Con_11 [ label="#0" ];
+ Store13 [ label=".b =" ];
+ Con_16 [ label="#2" ];
+ Store17 [ label=".a =" ];
+ Load18 [ label=".a" ];
+ Return19 [ shape=box style=filled fillcolor=yellow label="Return" ];
+ }
+ edge [ fontname=Helvetica, fontsize=8 ];
+ Stop3 -> Return19[taillabel=0 color=red];
+ new10 -> Start2:p0[taillabel=0 color=green];
+ Store13 -> Start2:p3[taillabel=1 color=blue];
+ Store13 -> new10[taillabel=2];
+ Store13 -> Con_11[taillabel=3];
+ Store17 -> Start2:p2[taillabel=1 color=blue];
+ Store17 -> new10[taillabel=2];
+ Store17 -> Con_16[taillabel=3];
+ Load18 -> Store17[taillabel=1 color=blue];
+ Load18 -> new10[taillabel=2];
+ Return19 -> Start2:p0[taillabel=0 color=red];
+ Return19 -> Load18[taillabel=1];
+ Return19 -> Store17[taillabel=2 color=blue];
+ Return19 -> Store13[taillabel=3 color=blue];
+ Return19 -> Start2:p4[taillabel=4 color=blue];
+}
diff --git a/docs/chapter10/example2b.svg b/docs/chapter10/example2b.svg
new file mode 100644
index 00000000..1ecf4de7
--- /dev/null
+++ b/docs/chapter10/example2b.svg
@@ -0,0 +1,189 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
+ "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<!-- Generated by graphviz version 2.43.0 (0)
+ -->
+<!-- Title: chapter10 Pages: 1 -->
+<svg width="369pt" height="464pt"
+ viewBox="0.00 0.00 368.60 464.00" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+<g id="graph0" class="graph" transform="scale(1 1) rotate(0) translate(4 460)">
+<title>chapter10</title>
+<polygon fill="white" stroke="transparent" points="-4,4 -4,-460 364.6,-460 364.6,4 -4,4"/>
+<g id="clust1" class="cluster">
+<title>cluster_Nodes</title>
+<polygon fill="none" stroke="black" points="8,-8 8,-448 346,-448 346,-8 8,-8"/>
+</g>
+<!-- Start2 -->
+<g id="node1" class="node">
+<title>Start2</title>
+<polygon fill="yellow" stroke="transparent" points="152,-411 152,-436 277,-436 277,-411 152,-411"/>
+<polygon fill="none" stroke="black" points="152,-411 152,-436 277,-436 277,-411 152,-411"/>
+<text text-anchor="start" x="196" y="-419.8" font-family="Times,serif" font-size="14.00">Start</text>
+<polygon fill="none" stroke="black" points="152,-380 152,-411 277,-411 277,-380 152,-380"/>
+<polygon fill="yellow" stroke="transparent" points="157,-385 157,-406 197,-406 197,-385 157,-385"/>
+<polygon fill="none" stroke="black" points="157,-385 157,-406 197,-406 197,-385 157,-385"/>
+<text text-anchor="start" x="160" y="-391.8" font-family="Times,serif" font-size="14.00">$ctrl</text>
+<polygon fill="none" stroke="black" points="197,-385 197,-406 222,-406 222,-385 197,-385"/>
+<text text-anchor="start" x="200" y="-391.8" font-family="Times,serif" font-size="14.00">$2</text>
+<polygon fill="none" stroke="black" points="222,-385 222,-406 247,-406 247,-385 222,-385"/>
+<text text-anchor="start" x="225" y="-391.8" font-family="Times,serif" font-size="14.00">$3</text>
+<polygon fill="none" stroke="black" points="247,-385 247,-406 272,-406 272,-385 247,-385"/>
+<text text-anchor="start" x="250" y="-391.8" font-family="Times,serif" font-size="14.00">$4</text>
+</g>
+<!-- Stop3 -->
+<g id="node2" class="node">
+<title>Stop3</title>
+<polygon fill="yellow" stroke="black" points="139,-52 85,-52 85,-16 139,-16 139,-52"/>
+<text text-anchor="middle" x="112" y="-30.3" font-family="Times,serif" font-size="14.00">Stop</text>
+</g>
+<!-- Return19 -->
+<g id="node9" class="node">
+<title>Return19</title>
+<polygon fill="yellow" stroke="black" points="145,-124 79,-124 79,-88 145,-88 145,-124"/>
+<text text-anchor="middle" x="112" y="-102.3" font-family="Times,serif" font-size="14.00">Return</text>
+</g>
+<!-- Stop3&#45;&gt;Return19 -->
+<g id="edge1" class="edge">
+<title>Stop3&#45;&gt;Return19</title>
+<path fill="none" stroke="red" d="M112,-52.3C112,-60.02 112,-69.29 112,-77.89"/>
+<polygon fill="red" stroke="red" points="108.5,-77.9 112,-87.9 115.5,-77.9 108.5,-77.9"/>
+<text text-anchor="middle" x="109" y="-54.9" font-family="Helvetica,sans-Serif" font-size="8.00">0</text>
+</g>
+<!-- new10 -->
+<g id="node3" class="node">
+<title>new10</title>
+<ellipse fill="none" stroke="black" cx="177" cy="-322" rx="49.29" ry="18"/>
+<text text-anchor="middle" x="177" y="-318.3" font-family="Times,serif" font-size="14.00">new Bar</text>
+</g>
+<!-- new10&#45;&gt;Start2 -->
+<g id="edge2" class="edge">
+<title>new10&#45;&gt;Start2:p0</title>
+<path fill="none" stroke="green" d="M177,-340.09C177,-349.55 177,-361.77 177,-373.69"/>
+<polygon fill="green" stroke="green" points="173.5,-374 177,-384 180.5,-374 173.5,-374"/>
+<text text-anchor="middle" x="174" y="-342.69" font-family="Helvetica,sans-Serif" font-size="8.00">0</text>
+</g>
+<!-- Con_11 -->
+<g id="node4" class="node">
+<title>Con_11</title>
+<ellipse fill="none" stroke="black" cx="291" cy="-322" rx="27" ry="18"/>
+<text text-anchor="middle" x="291" y="-318.3" font-family="Times,serif" font-size="14.00">#0</text>
+</g>
+<!-- Store13 -->
+<g id="node5" class="node">
+<title>Store13</title>
+<ellipse fill="none" stroke="black" cx="266" cy="-250" rx="30.59" ry="18"/>
+<text text-anchor="middle" x="266" y="-246.3" font-family="Times,serif" font-size="14.00">.b =</text>
+</g>
+<!-- Store13&#45;&gt;Start2 -->
+<g id="edge3" class="edge">
+<title>Store13&#45;&gt;Start2:p3</title>
+<path fill="none" stroke="blue" d="M259.43,-267.92C251.04,-290.96 237.36,-333.9 235.27,-373.91"/>
+<polygon fill="blue" stroke="blue" points="231.77,-373.91 235,-384 238.77,-374.1 231.77,-373.91"/>
+<text text-anchor="middle" x="256.43" y="-270.52" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- Store13&#45;&gt;new10 -->
+<g id="edge4" class="edge">
+<title>Store13&#45;&gt;new10</title>
+<path fill="none" stroke="black" d="M248.42,-264.83C235.97,-274.62 219.01,-287.96 204.75,-299.17"/>
+<polygon fill="black" stroke="black" points="202.41,-296.56 196.72,-305.49 206.74,-302.06 202.41,-296.56"/>
+<text text-anchor="middle" x="245.42" y="-267.43" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Store13&#45;&gt;Con_11 -->
+<g id="edge5" class="edge">
+<title>Store13&#45;&gt;Con_11</title>
+<path fill="none" stroke="black" d="M272.05,-267.95C274.91,-275.94 278.38,-285.67 281.57,-294.6"/>
+<polygon fill="black" stroke="black" points="278.34,-295.97 285,-304.21 284.94,-293.62 278.34,-295.97"/>
+<text text-anchor="middle" x="269.05" y="-270.55" font-family="Helvetica,sans-Serif" font-size="8.00">3</text>
+</g>
+<!-- Con_16 -->
+<g id="node6" class="node">
+<title>Con_16</title>
+<ellipse fill="none" stroke="black" cx="83" cy="-322" rx="27" ry="18"/>
+<text text-anchor="middle" x="83" y="-318.3" font-family="Times,serif" font-size="14.00">#2</text>
+</g>
+<!-- Store17 -->
+<g id="node7" class="node">
+<title>Store17</title>
+<ellipse fill="none" stroke="black" cx="74" cy="-250" rx="29.8" ry="18"/>
+<text text-anchor="middle" x="74" y="-246.3" font-family="Times,serif" font-size="14.00">.a =</text>
+</g>
+<!-- Store17&#45;&gt;Start2 -->
+<g id="edge6" class="edge">
+<title>Store17&#45;&gt;Start2:p2</title>
+<path fill="none" stroke="blue" d="M61.5,-266.67C47.91,-285.72 30.23,-318.07 47,-340 90.02,-396.26 197.33,-318.14 208.12,-373.87"/>
+<polygon fill="blue" stroke="blue" points="204.65,-374.34 209,-384 211.62,-373.74 204.65,-374.34"/>
+<text text-anchor="middle" x="58.5" y="-269.27" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- Store17&#45;&gt;new10 -->
+<g id="edge7" class="edge">
+<title>Store17&#45;&gt;new10</title>
+<path fill="none" stroke="black" d="M93.37,-264.17C108.16,-274.22 128.83,-288.27 145.92,-299.88"/>
+<polygon fill="black" stroke="black" points="144.25,-302.97 154.49,-305.7 148.18,-297.18 144.25,-302.97"/>
+<text text-anchor="middle" x="90.37" y="-266.77" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Store17&#45;&gt;Con_16 -->
+<g id="edge8" class="edge">
+<title>Store17&#45;&gt;Con_16</title>
+<path fill="none" stroke="black" d="M76.22,-268.3C77.22,-276.02 78.41,-285.29 79.51,-293.89"/>
+<polygon fill="black" stroke="black" points="76.05,-294.42 80.8,-303.9 83,-293.53 76.05,-294.42"/>
+<text text-anchor="middle" x="73.22" y="-270.9" font-family="Helvetica,sans-Serif" font-size="8.00">3</text>
+</g>
+<!-- Load18 -->
+<g id="node8" class="node">
+<title>Load18</title>
+<ellipse fill="none" stroke="black" cx="112" cy="-178" rx="27" ry="18"/>
+<text text-anchor="middle" x="112" y="-174.3" font-family="Times,serif" font-size="14.00">.a</text>
+</g>
+<!-- Load18&#45;&gt;new10 -->
+<g id="edge10" class="edge">
+<title>Load18&#45;&gt;new10</title>
+<path fill="none" stroke="black" d="M119.58,-195.57C130.78,-220.02 151.82,-266 165.09,-294.98"/>
+<polygon fill="black" stroke="black" points="161.92,-296.46 169.26,-304.1 168.28,-293.55 161.92,-296.46"/>
+<text text-anchor="middle" x="116.58" y="-198.17" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Load18&#45;&gt;Store17 -->
+<g id="edge9" class="edge">
+<title>Load18&#45;&gt;Store17</title>
+<path fill="none" stroke="blue" d="M103.19,-195.24C98.65,-203.6 93.01,-213.98 87.9,-223.39"/>
+<polygon fill="blue" stroke="blue" points="84.72,-221.91 83.03,-232.37 90.88,-225.25 84.72,-221.91"/>
+<text text-anchor="middle" x="100.19" y="-197.84" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- Return19&#45;&gt;Start2 -->
+<g id="edge11" class="edge">
+<title>Return19&#45;&gt;Start2:p0</title>
+<path fill="none" stroke="red" d="M78.92,-118.71C54.82,-129.48 25.06,-148.19 17,-177"/>
+<path fill="none" stroke="red" d="M17,-179C-2.42,-248.44 -5.52,-281.77 37,-340 66.51,-380.41 90.13,-391.98 133.12,-394.44"/>
+<polygon fill="red" stroke="red" points="133.09,-397.94 143.22,-394.85 133.37,-390.94 133.09,-397.94"/>
+<text text-anchor="middle" x="75.92" y="-112.31" font-family="Helvetica,sans-Serif" font-size="8.00">0</text>
+</g>
+<!-- Return19&#45;&gt;Start2 -->
+<g id="edge15" class="edge">
+<title>Return19&#45;&gt;Start2:p4</title>
+<path fill="none" stroke="blue" d="M337,-179C373.1,-264.02 373.34,-375.99 294.56,-392.84"/>
+<polygon fill="blue" stroke="blue" points="293.9,-389.4 284.56,-394.41 294.99,-396.32 293.9,-389.4"/>
+<text text-anchor="middle" x="334" y="-172.6" font-family="Helvetica,sans-Serif" font-size="8.00">4</text>
+</g>
+<!-- Return19&#45;&gt;Store13 -->
+<g id="edge14" class="edge">
+<title>Return19&#45;&gt;Store13</title>
+<path fill="none" stroke="blue" d="M145.2,-111.29C204,-119.77 321.73,-141.04 337,-177"/>
+<path fill="none" stroke="blue" d="M337,-179C346.91,-202.35 322.21,-221.91 299.27,-234.36"/>
+<polygon fill="blue" stroke="blue" points="297.63,-231.27 290.32,-238.94 300.82,-237.5 297.63,-231.27"/>
+<text text-anchor="middle" x="148.2" y="-104.89" font-family="Helvetica,sans-Serif" font-size="8.00">3</text>
+</g>
+<!-- Return19&#45;&gt;Store17 -->
+<g id="edge13" class="edge">
+<title>Return19&#45;&gt;Store17</title>
+<path fill="none" stroke="blue" d="M17,-179C11.2,-199.75 28.07,-218.41 44.94,-231.23"/>
+<polygon fill="blue" stroke="blue" points="42.94,-234.1 53.12,-237.04 46.99,-228.4 42.94,-234.1"/>
+<text text-anchor="middle" x="14" y="-172.6" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Return19&#45;&gt;Load18 -->
+<g id="edge12" class="edge">
+<title>Return19&#45;&gt;Load18</title>
+<path fill="none" stroke="black" d="M112,-124.3C112,-132.02 112,-141.29 112,-149.89"/>
+<polygon fill="black" stroke="black" points="108.5,-149.9 112,-159.9 115.5,-149.9 108.5,-149.9"/>
+<text text-anchor="middle" x="109" y="-126.9" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+</g>
+</svg>
diff --git a/docs/chapter10/example2c.gv b/docs/chapter10/example2c.gv
new file mode 100644
index 00000000..76db03bb
--- /dev/null
+++ b/docs/chapter10/example2c.gv
@@ -0,0 +1,53 @@
+digraph chapter10 {
+/*
+struct Bar {
+ int a;
+ int b;
+}
+struct Foo {
+ int x;
+}
+Foo? foo = null;
+Bar bar = new Bar;
+bar.a = 1;
+bar.a = 2;
+return bar.a;
+
+*/
+ rankdir=BT;
+ concentrate="true";
+ compound="true";
+ subgraph cluster_Nodes {
+ Con_16 [ label="#2" ];
+ Store17 [ label=".a =" ];
+ Start2 [ shape=plaintext label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+ <TR><TD BGCOLOR="yellow">Start</TD></TR>
+ <TR><TD>
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD PORT="p0" BGCOLOR="yellow">$ctrl</TD><TD PORT="p2">$2</TD><TD PORT="p3">$3</TD><TD PORT="p4">$4</TD></TR>
+ </TABLE>
+ </TD></TR>
+ </TABLE>>
+ ];
+ Return19 [ shape=box style=filled fillcolor=yellow label="Return" ];
+ Stop3 [ shape=box style=filled fillcolor=yellow label="Stop" ];
+ new10 [ label="new Bar" ];
+ Con_11 [ label="#0" ];
+ Store13 [ label=".b =" ];
+ }
+ edge [ fontname=Helvetica, fontsize=8 ];
+ Store17 -> Start2:p2[taillabel=1 color=blue];
+ Store17 -> new10[taillabel=2];
+ Store17 -> Con_16[taillabel=3];
+ Return19 -> Start2:p0[taillabel=0 color=red];
+ Return19 -> Con_16[taillabel=1];
+ Return19 -> Store17[taillabel=2 color=blue];
+ Return19 -> Store13[taillabel=3 color=blue];
+ Return19 -> Start2:p4[taillabel=4 color=blue];
+ Stop3 -> Return19[taillabel=0 color=red];
+ new10 -> Start2:p0[taillabel=0 color=green];
+ Store13 -> Start2:p3[taillabel=1 color=blue];
+ Store13 -> new10[taillabel=2];
+ Store13 -> Con_11[taillabel=3];
+}
diff --git a/docs/chapter10/example2c.svg b/docs/chapter10/example2c.svg
new file mode 100644
index 00000000..d70660a2
--- /dev/null
+++ b/docs/chapter10/example2c.svg
@@ -0,0 +1,168 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
+ "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<!-- Generated by graphviz version 2.43.0 (0)
+ -->
+<!-- Title: chapter10 Pages: 1 -->
+<svg width="362pt" height="392pt"
+ viewBox="0.00 0.00 362.00 392.00" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+<g id="graph0" class="graph" transform="scale(1 1) rotate(0) translate(4 388)">
+<title>chapter10</title>
+<polygon fill="white" stroke="transparent" points="-4,4 -4,-388 358,-388 358,4 -4,4"/>
+<g id="clust1" class="cluster">
+<title>cluster_Nodes</title>
+<polygon fill="none" stroke="black" points="8,-8 8,-376 346,-376 346,-8 8,-8"/>
+</g>
+<!-- Con_16 -->
+<g id="node1" class="node">
+<title>Con_16</title>
+<ellipse fill="none" stroke="black" cx="63" cy="-250" rx="27" ry="18"/>
+<text text-anchor="middle" x="63" y="-246.3" font-family="Times,serif" font-size="14.00">#2</text>
+</g>
+<!-- Store17 -->
+<g id="node2" class="node">
+<title>Store17</title>
+<ellipse fill="none" stroke="black" cx="130" cy="-178" rx="29.8" ry="18"/>
+<text text-anchor="middle" x="130" y="-174.3" font-family="Times,serif" font-size="14.00">.a =</text>
+</g>
+<!-- Store17&#45;&gt;Con_16 -->
+<g id="edge3" class="edge">
+<title>Store17&#45;&gt;Con_16</title>
+<path fill="none" stroke="black" d="M115.79,-193.85C106.64,-203.4 94.58,-216.01 84.3,-226.75"/>
+<polygon fill="black" stroke="black" points="81.57,-224.53 77.19,-234.18 86.63,-229.37 81.57,-224.53"/>
+<text text-anchor="middle" x="112.79" y="-196.45" font-family="Helvetica,sans-Serif" font-size="8.00">3</text>
+</g>
+<!-- Start2 -->
+<g id="node3" class="node">
+<title>Start2</title>
+<polygon fill="yellow" stroke="transparent" points="152,-339 152,-364 277,-364 277,-339 152,-339"/>
+<polygon fill="none" stroke="black" points="152,-339 152,-364 277,-364 277,-339 152,-339"/>
+<text text-anchor="start" x="196" y="-347.8" font-family="Times,serif" font-size="14.00">Start</text>
+<polygon fill="none" stroke="black" points="152,-308 152,-339 277,-339 277,-308 152,-308"/>
+<polygon fill="yellow" stroke="transparent" points="157,-313 157,-334 197,-334 197,-313 157,-313"/>
+<polygon fill="none" stroke="black" points="157,-313 157,-334 197,-334 197,-313 157,-313"/>
+<text text-anchor="start" x="160" y="-319.8" font-family="Times,serif" font-size="14.00">$ctrl</text>
+<polygon fill="none" stroke="black" points="197,-313 197,-334 222,-334 222,-313 197,-313"/>
+<text text-anchor="start" x="200" y="-319.8" font-family="Times,serif" font-size="14.00">$2</text>
+<polygon fill="none" stroke="black" points="222,-313 222,-334 247,-334 247,-313 222,-313"/>
+<text text-anchor="start" x="225" y="-319.8" font-family="Times,serif" font-size="14.00">$3</text>
+<polygon fill="none" stroke="black" points="247,-313 247,-334 272,-334 272,-313 247,-313"/>
+<text text-anchor="start" x="250" y="-319.8" font-family="Times,serif" font-size="14.00">$4</text>
+</g>
+<!-- Store17&#45;&gt;Start2 -->
+<g id="edge1" class="edge">
+<title>Store17&#45;&gt;Start2:p2</title>
+<path fill="none" stroke="blue" d="M122.08,-195.45C114.22,-214.42 105.15,-245.81 119,-268 140.46,-302.38 197.41,-273.74 207.47,-301.89"/>
+<polygon fill="blue" stroke="blue" points="204.04,-302.64 209,-312 210.97,-301.59 204.04,-302.64"/>
+<text text-anchor="middle" x="119.08" y="-198.05" font-family="Helvetica,sans-Serif" font-size="8.00">1</text>
+</g>
+<!-- new10 -->
+<g id="node6" class="node">
+<title>new10</title>
+<ellipse fill="none" stroke="black" cx="177" cy="-250" rx="49.29" ry="18"/>
+<text text-anchor="middle" x="177" y="-246.3" font-family="Times,serif" font-size="14.00">new Bar</text>
+</g>
+<!-- Store17&#45;&gt;new10 -->
+<g id="edge2" class="edge">
+<title>Store17&#45;&gt;new10</title>
+<path fill="none" stroke="black" d="M140.67,-194.88C146.39,-203.41 153.58,-214.11 160.05,-223.75"/>
+<polygon fill="black" stroke="black" points="157.24,-225.85 165.72,-232.2 163.05,-221.95 157.24,-225.85"/>
+<text text-anchor="middle" x="137.67" y="-197.48" font-family="Helvetica,sans-Serif" font-size="8.00">2</text>
+</g>
+<!-- Return19 -->
+<g id="node4" class="node">
+<title>Return19</title>
+<polygon fill="yellow" stroke="black" points="223,-124 157,-124 157,-88 223,-88 223,-124"/>
+<text text-anchor="middle" x="190" y="-102.3" font-family="Times,serif" font-size="14.00">Return</text>
+</g>
+<!-- Return19&#45;&gt;Con_16 -->
+<g id="edge5" class="edge">
+<title>Return19&#45;&gt;Con_16</title>
+<path fill="none" stroke="black" d="M17,-179C8.57,-197.2 22.58,-216.12 37.3,-229.69"/>
+<polygon fill="black" stroke="black" points="35.08,-232.39 44.95,-236.26 39.65,-227.09 35.08,-232.39"/>
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+ <mxCell id="71" value="" style="endArrow=none;html=1;exitX=0.5;exitY=0;exitDx=0;exitDy=0;" parent="1" source="64" target="61" edge="1">
+ <mxGeometry width="50" height="50" relative="1" as="geometry">
+ <mxPoint x="1040" y="303.85" as="sourcePoint"/>
+ <mxPoint x="934.0846571342449" y="264.9985560366689" as="targetPoint"/>
+ </mxGeometry>
+ </mxCell>
+ <mxCell id="72" value="" style="endArrow=none;html=1;entryX=0.5;entryY=1;entryDx=0;entryDy=0;exitX=1;exitY=0;exitDx=0;exitDy=0;" parent="1" source="74" target="64" edge="1">
+ <mxGeometry width="50" height="50" relative="1" as="geometry">
+ <mxPoint x="932.677669529664" y="381.1723304703361" as="sourcePoint"/>
+ <mxPoint x="1020" y="353.85" as="targetPoint"/>
+ </mxGeometry>
+ </mxCell>
+ <mxCell id="73" value="#2" style="text;html=1;strokeColor=none;fillColor=none;align=center;verticalAlign=middle;whiteSpace=wrap;rounded=0;" parent="1" vertex="1">
+ <mxGeometry x="820" y="303.85" width="40" height="30" as="geometry"/>
+ </mxCell>
+ <mxCell id="74" value="MEM#BOT" style="ellipse;whiteSpace=wrap;html=1;aspect=fixed;" parent="1" vertex="1">
+ <mxGeometry x="870" y="425" width="70" height="70" as="geometry"/>
+ </mxCell>
+ <mxCell id="75" value="" style="endArrow=none;html=1;entryX=1;entryY=0.5;entryDx=0;entryDy=0;exitX=0;exitY=0;exitDx=0;exitDy=0;" parent="1" source="61" target="2" edge="1">
+ <mxGeometry width="50" height="50" relative="1" as="geometry">
+ <mxPoint x="1030" y="130" as="sourcePoint"/>
+ <mxPoint x="1080" y="80" as="targetPoint"/>
+ </mxGeometry>
+ </mxCell>
+ <mxCell id="76" value="" style="endArrow=none;html=1;entryX=0.219;entryY=0.957;entryDx=0;entryDy=0;entryPerimeter=0;" parent="1" source="5" target="74" edge="1">
+ <mxGeometry width="50" height="50" relative="1" as="geometry">
+ <mxPoint x="610" y="640" as="sourcePoint"/>
+ <mxPoint x="660" y="590" as="targetPoint"/>
+ </mxGeometry>
+ </mxCell>
+ <mxCell id="79" value="Null" style="ellipse;whiteSpace=wrap;html=1;aspect=fixed;" parent="1" vertex="1">
+ <mxGeometry x="450" y="296.15" width="51.92" height="51.92" as="geometry"/>
+ </mxCell>
+ <mxCell id="81" value="*void" style="ellipse;whiteSpace=wrap;html=1;aspect=fixed;" parent="1" vertex="1">
+ <mxGeometry x="700" y="295.19" width="53.85" height="53.85" as="geometry"/>
+ </mxCell>
+ <mxCell id="82" value="" style="endArrow=none;html=1;" parent="1" source="23" target="81" edge="1">
+ <mxGeometry width="50" height="50" relative="1" as="geometry">
+ <mxPoint x="540" y="550" as="sourcePoint"/>
+ <mxPoint x="760" y="310" as="targetPoint"/>
+ </mxGeometry>
+ </mxCell>
+ <mxCell id="85" value="" style="endArrow=none;html=1;" parent="1" source="23" target="79" edge="1">
+ <mxGeometry width="50" height="50" relative="1" as="geometry">
+ <mxPoint x="555" y="340" as="sourcePoint"/>
+ <mxPoint x="690" y="230" as="targetPoint"/>
+ </mxGeometry>
+ </mxCell>
+ <mxCell id="87" value="*S1" style="ellipse;whiteSpace=wrap;html=1;aspect=fixed;" parent="1" vertex="1">
+ <mxGeometry x="630" y="240" width="38.85" height="38.85" as="geometry"/>
+ </mxCell>
+ <mxCell id="88" value="" style="endArrow=none;html=1;" parent="1" source="79" target="89" edge="1">
+ <mxGeometry width="50" height="50" relative="1" as="geometry">
+ <mxPoint x="620" y="290" as="sourcePoint"/>
+ <mxPoint x="650" y="290" as="targetPoint"/>
+ </mxGeometry>
+ </mxCell>
+ <mxCell id="89" value="*S1?" style="ellipse;whiteSpace=wrap;html=1;aspect=fixed;" parent="1" vertex="1">
+ <mxGeometry x="700" y="430" width="50" height="50" as="geometry"/>
+ </mxCell>
+ <mxCell id="90" value="" style="endArrow=none;html=1;" parent="1" source="89" target="87" edge="1">
+ <mxGeometry width="50" height="50" relative="1" as="geometry">
+ <mxPoint x="640" y="240" as="sourcePoint"/>
+ <mxPoint x="690" y="190" as="targetPoint"/>
+ </mxGeometry>
+ </mxCell>
+ <mxCell id="92" value="*S2" style="ellipse;whiteSpace=wrap;html=1;aspect=fixed;" parent="1" vertex="1">
+ <mxGeometry x="540" y="240" width="40" height="40" as="geometry"/>
+ </mxCell>
+ <mxCell id="93" value="" style="endArrow=none;html=1;" parent="1" source="22" target="92" edge="1">
+ <mxGeometry width="50" height="50" relative="1" as="geometry">
+ <mxPoint x="650" y="70" as="sourcePoint"/>
+ <mxPoint x="700" y="20" as="targetPoint"/>
+ </mxGeometry>
+ </mxCell>
+ <mxCell id="94" value="" style="endArrow=none;html=1;" parent="1" source="81" target="92" edge="1">
+ <mxGeometry width="50" height="50" relative="1" as="geometry">
+ <mxPoint x="680" y="640" as="sourcePoint"/>
+ <mxPoint x="730" y="590" as="targetPoint"/>
+ </mxGeometry>
+ </mxCell>
+ <mxCell id="95" value="" style="endArrow=none;html=1;" parent="1" source="81" target="87" edge="1">
+ <mxGeometry width="50" height="50" relative="1" as="geometry">
+ <mxPoint x="650" y="640" as="sourcePoint"/>
+ <mxPoint x="700" y="590" as="targetPoint"/>
+ </mxGeometry>
+ </mxCell>
+ <mxCell id="96" value="*S2?" style="ellipse;whiteSpace=wrap;html=1;aspect=fixed;" parent="1" vertex="1">
+ <mxGeometry x="598.85" y="430" width="50" height="50" as="geometry"/>
+ </mxCell>
+ <mxCell id="101" value="" style="endArrow=none;html=1;exitX=0;exitY=0;exitDx=0;exitDy=0;" parent="1" source="96" target="79" edge="1">
+ <mxGeometry width="50" height="50" relative="1" as="geometry">
+ <mxPoint x="800" y="760" as="sourcePoint"/>
+ <mxPoint x="850" y="710" as="targetPoint"/>
+ </mxGeometry>
+ </mxCell>
+ <mxCell id="102" value="" style="endArrow=none;html=1;exitX=0.5;exitY=0;exitDx=0;exitDy=0;" parent="1" source="96" target="92" edge="1">
+ <mxGeometry width="50" height="50" relative="1" as="geometry">
+ <mxPoint x="730" y="670" as="sourcePoint"/>
+ <mxPoint x="600" y="240" as="targetPoint"/>
+ </mxGeometry>
+ </mxCell>
+ <mxCell id="103" value="" style="endArrow=none;html=1;" parent="1" source="23" target="96" edge="1">
+ <mxGeometry width="50" height="50" relative="1" as="geometry">
+ <mxPoint x="700" y="530" as="sourcePoint"/>
+ <mxPoint x="750" y="480" as="targetPoint"/>
+ </mxGeometry>
+ </mxCell>
+ <mxCell id="104" value="" style="endArrow=none;html=1;exitX=0.5;exitY=0;exitDx=0;exitDy=0;" parent="1" source="81" target="22" edge="1">
+ <mxGeometry width="50" height="50" relative="1" as="geometry">
+ <mxPoint x="210" y="720" as="sourcePoint"/>
+ <mxPoint x="610" y="160" as="targetPoint"/>
+ </mxGeometry>
+ </mxCell>
+ <mxCell id="105" value="Control" style="text;html=1;strokeColor=none;fillColor=none;align=center;verticalAlign=middle;whiteSpace=wrap;rounded=0;" parent="1" vertex="1">
+ <mxGeometry x="20" y="165" width="60" height="30" as="geometry"/>
+ </mxCell>
+ <mxCell id="106" value="Integer" style="text;html=1;strokeColor=none;fillColor=none;align=center;verticalAlign=middle;whiteSpace=wrap;rounded=0;" parent="1" vertex="1">
+ <mxGeometry x="140" y="165" width="60" height="30" as="geometry"/>
+ </mxCell>
+ <mxCell id="107" value="Struct" style="text;html=1;strokeColor=none;fillColor=none;align=center;verticalAlign=middle;whiteSpace=wrap;rounded=0;" parent="1" vertex="1">
+ <mxGeometry x="330" y="165" width="60" height="30" as="geometry"/>
+ </mxCell>
+ <mxCell id="108" value="MemPtr" style="text;html=1;strokeColor=none;fillColor=none;align=center;verticalAlign=middle;whiteSpace=wrap;rounded=0;" parent="1" vertex="1">
+ <mxGeometry x="580" y="85" width="60" height="30" as="geometry"/>
+ </mxCell>
+ <mxCell id="109" value="Mem" style="text;html=1;strokeColor=none;fillColor=none;align=center;verticalAlign=middle;whiteSpace=wrap;rounded=0;" parent="1" vertex="1">
+ <mxGeometry x="875" y="115" width="60" height="30" as="geometry"/>
+ </mxCell>
+ </root>
+ </mxGraphModel>
+ </diagram>
+</mxfile> \ No newline at end of file
diff --git a/docs/chapter10/lattice.gv b/docs/chapter10/lattice.gv
new file mode 100644
index 00000000..7723e2a2
--- /dev/null
+++ b/docs/chapter10/lattice.gv
@@ -0,0 +1,161 @@
+digraph Lattice {
+ compound = true;
+ // Define nodes
+ splines=false;
+ node [shape=circle, style=filled];
+ nodesep=0.6;
+
+ TOP [label=<<B>⊤</B >>, fillcolor=black, fontcolor=white];
+ BOT [label=<<B>⊥</B>>, fillcolor=black, fontcolor=white];
+
+ // ----------------------
+ // Control
+ XCTRL [label=<<B>⊤</B >:ctrl>, fillcolor=yellow, shape=oval];
+ CTRL [label=<<B>⊥</B>:ctrl>, fillcolor=yellow, shape=oval];
+
+ TOP -> XCTRL;
+ XCTRL -> CTRL;
+ CTRL -> BOT;
+
+ // ----------------------
+ // Integers
+ INT_TOP [label=<<B>⊤</B >:int>, fillcolor=lightblue, shape=oval];
+ INT_BOT [label=<<B>⊥</B>:int>, fillcolor=lightblue, shape=oval];
+
+ INT_MINDOTS [label="...", fillcolor=lightblue, shape=oval];
+ INT_ZERO [label="0" , fillcolor=lightblue];
+ INT_MAXDOTS [label="...", fillcolor=lightblue, shape=oval];
+
+ TOP -> INT_TOP;
+ INT_TOP -> INT_MINDOTS;
+ INT_TOP -> INT_ZERO;
+ INT_TOP -> INT_MAXDOTS;
+ INT_MINDOTS -> INT_BOT;
+ INT_ZERO -> INT_BOT;
+ INT_MAXDOTS -> INT_BOT;
+ INT_BOT -> BOT;
+
+ INT_MINDOTS -> INT_ZERO -> INT_MAXDOTS [style=invis];
+
+ // ----------------------
+ // Pointers, just a boolean nil/not and a struct
+ PTR [shape=none, fillcolor=none, label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD BGCOLOR="green"><FONT color="white">*ptr</FONT></TD></TR>
+ <TR><TD BGCOLOR="lightgreen">struct</TD></TR>
+ </TABLE>
+ >];
+ PTR0 [shape=none, fillcolor=none, label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD BGCOLOR="green"><FONT color="white">*ptr?</FONT></TD></TR>
+ <TR><TD BGCOLOR="lightgreen">struct</TD></TR>
+ </TABLE>
+ >];
+
+ TOP -> PTR;
+ PTR -> PTR0;
+ PTR0 -> BOT;
+
+ // ----------------------
+ // Structs
+ STRUCT_TOP [label=<<B>⊤</B >:struct>, fillcolor=lightgreen, shape=oval];
+ STRUCT_BOT [label=<<B>⊥</B>:struct>, fillcolor=lightgreen, shape=oval];
+
+ STRUCT_S1 [shape=none, fillcolor=none, label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD BGCOLOR="lightgreen">field</TD><TD BGCOLOR="lightblue:green" gradientangle="315">int/ptr</TD></TR>
+ </TABLE>
+ >];
+ STRUCT_S2 [shape=none, fillcolor=none, label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD BGCOLOR="lightgreen">field</TD><TD BGCOLOR="lightblue:green" gradientangle="315">int/ptr</TD></TR>
+ <TR><TD BGCOLOR="lightgreen">field</TD><TD BGCOLOR="lightblue:green" gradientangle="315">int/ptr</TD></TR>
+ </TABLE>
+ >];
+ STRUCT_SN [shape=none, fillcolor=none, label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TR><TD BGCOLOR="lightgreen">field</TD><TD BGCOLOR="lightblue:green" gradientangle="315">int/ptr</TD></TR>
+ <TR><TD BGCOLOR="lightgreen">... </TD><TD BGCOLOR="lightblue:green" gradientangle="315">int/ptr</TD></TR>
+ <TR><TD BGCOLOR="lightgreen">field</TD><TD BGCOLOR="lightblue:green" gradientangle="315">int/ptr</TD></TR>
+ </TABLE>
+ >];
+
+
+ TOP -> STRUCT_TOP;
+ STRUCT_TOP -> STRUCT_S1;
+ STRUCT_TOP -> STRUCT_S2;
+ STRUCT_TOP -> STRUCT_SN;
+ STRUCT_S1 -> STRUCT_BOT;
+ STRUCT_S2 -> STRUCT_BOT;
+ STRUCT_SN -> STRUCT_BOT;
+ STRUCT_BOT -> BOT;
+
+ STRUCT_S1 -> STRUCT_S2 -> STRUCT_SN [style=invis];
+
+ // ----------------------
+ // Memory
+ MEM_TOP [label=<<B>⊤</B >:mem>, fillcolor=blue, fontcolor=white, shape=oval];
+ MEM_BOT [label=<<B>⊥</B>:mem>, fillcolor=blue, fontcolor=white, shape=oval];
+ MEM_ALIAS1 [label="#1" , fillcolor=blue, fontcolor=white];
+ MEM_ALIASDOTS [label="..." , fillcolor=blue, fontcolor=white, shape=oval];
+ MEM_ALIASN [label="#n" , fillcolor=blue, fontcolor=white];
+
+ TOP -> MEM_TOP;
+ MEM_TOP -> MEM_ALIAS1;
+ MEM_TOP -> MEM_ALIASDOTS;
+ MEM_TOP -> MEM_ALIASN;
+ MEM_ALIAS1 -> MEM_BOT;
+ MEM_ALIASDOTS -> MEM_BOT;
+ MEM_ALIASN -> MEM_BOT;
+ MEM_BOT -> BOT;
+
+ MEM_ALIAS1 -> MEM_ALIASDOTS -> MEM_ALIASN [style=invis];
+
+ // ----------------------
+ // Tuples
+
+ TUPLE_TOP [label=<<B>⊤</B >:tuple>, fillcolor=pink, shape=oval];
+ TUPLE_BOT [label=<<B>⊥</B>:tuple>, fillcolor=pink, shape=oval];
+
+ TUPLE1 [shape=none, fillcolor=none, label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TH><TD BGCOLOR="pink">Tuple</TD></TH>
+ <TR><TD BGCOLOR="black" ><FONT color="white">type</FONT></TD></TR>
+ </TABLE>
+ >];
+ TUPLE2 [shape=none, fillcolor=none, label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TH><TD BGCOLOR="pink">Tuple</TD></TH>
+ <TR><TD BGCOLOR="black" ><FONT color="white">type</FONT></TD></TR>
+ <TR><TD BGCOLOR="black" ><FONT color="white">type</FONT></TD></TR>
+ </TABLE>
+ >];
+ TUPLEN [shape=none, fillcolor=none, label=<
+ <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+ <TH><TD BGCOLOR="pink">Tuple</TD></TH>
+ <TR><TD BGCOLOR="black" ><FONT color="white">type</FONT></TD></TR>
+ <TR><TD BGCOLOR="black" ><FONT color="white">...</FONT></TD></TR>
+ <TR><TD BGCOLOR="black" ><FONT color="white">type</FONT></TD></TR>
+ </TABLE>
+ >];
+
+
+ TOP -> TUPLE_TOP;
+ TUPLE_TOP -> TUPLE1;
+ TUPLE_TOP -> TUPLE2;
+ TUPLE_TOP -> TUPLEN;
+ TUPLE1 -> TUPLE_BOT;
+ TUPLE2 -> TUPLE_BOT;
+ TUPLEN -> TUPLE_BOT;
+ TUPLE_BOT -> BOT;
+
+ // ----------------------
+ // Additional customization
+ {rank=same; TOP;}
+ {rank=same; INT_TOP; XCTRL; STRUCT_TOP; MEM_TOP; TUPLE_TOP}
+ {rank=same; INT_MINDOTS; INT_ZERO; INT_MAXDOTS;
+ STRUCT_S1; STRUCT_S2; STRUCT_SN;
+ MEM_ALIAS1; MEM_ALIASDOTS; MEM_ALIASN;}
+ {rank=same; INT_BOT; CTRL; STRUCT_BOT; MEM_BOT; TUPLE_BOT}
+ {rank=same; BOT;}
+}
diff --git a/docs/chapter10/lattice.svg b/docs/chapter10/lattice.svg
new file mode 100644
index 00000000..9eb36bbe
--- /dev/null
+++ b/docs/chapter10/lattice.svg
@@ -0,0 +1,516 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
+ "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<!-- Generated by graphviz version 12.2.0 (20241103.1931)
+ -->
+<!-- Title: Lattice Pages: 1 -->
+<svg width="1308pt" height="440pt"
+ viewBox="0.00 0.00 1307.51 440.50" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+<g id="graph0" class="graph" transform="scale(1 1) rotate(0) translate(4 436.5)">
+<title>Lattice</title>
+<polygon fill="white" stroke="none" points="-4,4 -4,-436.5 1303.51,-436.5 1303.51,4 -4,4"/>
+<!-- TOP -->
+<g id="node1" class="node">
+<title>TOP</title>
+<ellipse fill="black" stroke="black" cx="478.51" cy="-411.37" rx="21.12" ry="21.12"/>
+<text text-anchor="start" x="470.63" y="-406.95" font-family="Times New Roman,serif" font-weight="bold" font-size="14.00" fill="white">⊤</text>
+</g>
+<!-- XCTRL -->
+<g id="node3" class="node">
+<title>XCTRL</title>
+<ellipse fill="yellow" stroke="black" cx="36.51" cy="-327.75" rx="36.51" ry="18"/>
+<text text-anchor="start" x="17.76" y="-323.7" font-family="Times New Roman,serif" font-weight="bold" font-size="14.00">⊤</text>
+<text text-anchor="start" x="33.51" y="-323.7" font-family="Times New Roman,serif" font-size="14.00">:ctrl</text>
+</g>
+<!-- TOP&#45;&gt;XCTRL -->
+<g id="edge1" class="edge">
+<title>TOP&#45;&gt;XCTRL</title>
+<path fill="none" stroke="black" d="M457.49,-406.49C389.63,-393.96 175.41,-354.4 81.44,-337.04"/>
+<polygon fill="black" stroke="black" points="82.28,-333.64 71.81,-335.27 81.01,-340.53 82.28,-333.64"/>
+</g>
+<!-- INT_TOP -->
+<g id="node5" class="node">
+<title>INT_TOP</title>
+<ellipse fill="lightblue" stroke="black" cx="220.51" cy="-327.75" rx="33.95" ry="18"/>
+<text text-anchor="start" x="203.63" y="-323.7" font-family="Times New Roman,serif" font-weight="bold" font-size="14.00">⊤</text>
+<text text-anchor="start" x="219.38" y="-323.7" font-family="Times New Roman,serif" font-size="14.00">:int</text>
+</g>
+<!-- TOP&#45;&gt;INT_TOP -->
+<g id="edge4" class="edge">
+<title>TOP&#45;&gt;INT_TOP</title>
+<path fill="none" stroke="black" d="M458.26,-403.97C415.59,-390.47 315.75,-358.88 259.97,-341.23"/>
+<polygon fill="black" stroke="black" points="261.14,-337.93 250.55,-338.25 259.03,-344.61 261.14,-337.93"/>
+</g>
+<!-- PTR -->
+<g id="node10" class="node">
+<title>PTR</title>
+<polygon fill="none" stroke="none" points="387.51,-354.25 333.51,-354.25 333.51,-301.25 387.51,-301.25 387.51,-354.25"/>
+<polygon fill="green" stroke="none" points="342.51,-327.75 342.51,-350.25 378.51,-350.25 378.51,-327.75 342.51,-327.75"/>
+<polygon fill="none" stroke="black" points="342.51,-327.75 342.51,-350.25 378.51,-350.25 378.51,-327.75 342.51,-327.75"/>
+<text text-anchor="start" x="349.63" y="-333.95" font-family="Times New Roman,serif" font-size="14.00" fill="white">*ptr</text>
+<polygon fill="lightgreen" stroke="none" points="342.51,-305.25 342.51,-327.75 378.51,-327.75 378.51,-305.25 342.51,-305.25"/>
+<polygon fill="none" stroke="black" points="342.51,-305.25 342.51,-327.75 378.51,-327.75 378.51,-305.25 342.51,-305.25"/>
+<text text-anchor="start" x="345.51" y="-311.45" font-family="Times New Roman,serif" font-size="14.00">struct</text>
+</g>
+<!-- TOP&#45;&gt;PTR -->
+<g id="edge14" class="edge">
+<title>TOP&#45;&gt;PTR</title>
+<path fill="none" stroke="black" d="M461.35,-398.5C444.42,-386.79 418.03,-368.54 396.49,-353.64"/>
+<polygon fill="black" stroke="black" points="398.75,-350.95 388.54,-348.14 394.77,-356.7 398.75,-350.95"/>
+</g>
+<!-- STRUCT_TOP -->
+<g id="node12" class="node">
+<title>STRUCT_TOP</title>
+<ellipse fill="lightgreen" stroke="black" cx="514.51" cy="-327.75" rx="44.7" ry="18"/>
+<text text-anchor="start" x="489.76" y="-323.7" font-family="Times New Roman,serif" font-weight="bold" font-size="14.00">⊤</text>
+<text text-anchor="start" x="505.51" y="-323.7" font-family="Times New Roman,serif" font-size="14.00">:struct</text>
+</g>
+<!-- TOP&#45;&gt;STRUCT_TOP -->
+<g id="edge17" class="edge">
+<title>TOP&#45;&gt;STRUCT_TOP</title>
+<path fill="none" stroke="black" d="M486.86,-391.44C491.45,-381.02 497.24,-367.9 502.33,-356.35"/>
+<polygon fill="black" stroke="black" points="505.5,-357.86 506.33,-347.29 499.09,-355.03 505.5,-357.86"/>
+</g>
+<!-- MEM_TOP -->
+<g id="node17" class="node">
+<title>MEM_TOP</title>
+<ellipse fill="blue" stroke="black" cx="853.51" cy="-327.75" rx="43.67" ry="18"/>
+<text text-anchor="start" x="829.51" y="-323.7" font-family="Times New Roman,serif" font-weight="bold" font-size="14.00" fill="white">⊤</text>
+<text text-anchor="start" x="845.26" y="-323.7" font-family="Times New Roman,serif" font-size="14.00" fill="white">:mem</text>
+</g>
+<!-- TOP&#45;&gt;MEM_TOP -->
+<g id="edge27" class="edge">
+<title>TOP&#45;&gt;MEM_TOP</title>
+<path fill="none" stroke="black" d="M499.2,-405.87C556.98,-393.29 721.22,-357.54 804.21,-339.48"/>
+<polygon fill="black" stroke="black" points="804.86,-342.92 813.89,-337.37 803.37,-336.08 804.86,-342.92"/>
+</g>
+<!-- TUPLE_TOP -->
+<g id="node22" class="node">
+<title>TUPLE_TOP</title>
+<ellipse fill="pink" stroke="black" cx="1126.51" cy="-327.75" rx="42.65" ry="18"/>
+<text text-anchor="start" x="1103.26" y="-323.7" font-family="Times New Roman,serif" font-weight="bold" font-size="14.00">⊤</text>
+<text text-anchor="start" x="1119.01" y="-323.7" font-family="Times New Roman,serif" font-size="14.00">:tuple</text>
+</g>
+<!-- TOP&#45;&gt;TUPLE_TOP -->
+<g id="edge37" class="edge">
+<title>TOP&#45;&gt;TUPLE_TOP</title>
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+<polygon fill="black" stroke="black" points="1074.97,-338.77 1084.46,-334.05 1074.1,-331.82 1074.97,-338.77"/>
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+<!-- BOT -->
+<g id="node2" class="node">
+<title>BOT</title>
+<ellipse fill="black" stroke="black" cx="448.51" cy="-21.12" rx="21.12" ry="21.12"/>
+<text text-anchor="start" x="440.63" y="-16.7" font-family="Times New Roman,serif" font-weight="bold" font-size="14.00" fill="white">⊥</text>
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+<!-- CTRL -->
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+<title>CTRL</title>
+<ellipse fill="yellow" stroke="black" cx="36.51" cy="-104.75" rx="36.51" ry="18"/>
+<text text-anchor="start" x="17.76" y="-100.7" font-family="Times New Roman,serif" font-weight="bold" font-size="14.00">⊥</text>
+<text text-anchor="start" x="33.51" y="-100.7" font-family="Times New Roman,serif" font-size="14.00">:ctrl</text>
+</g>
+<!-- XCTRL&#45;&gt;CTRL -->
+<g id="edge2" class="edge">
+<title>XCTRL&#45;&gt;CTRL</title>
+<path fill="none" stroke="black" d="M36.51,-309.5C36.51,-271.02 36.51,-181.25 36.51,-134.4"/>
+<polygon fill="black" stroke="black" points="40.01,-134.45 36.51,-124.45 33.01,-134.45 40.01,-134.45"/>
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+<!-- CTRL&#45;&gt;BOT -->
+<g id="edge3" class="edge">
+<title>CTRL&#45;&gt;BOT</title>
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+<polygon fill="black" stroke="black" points="417.29,-31.88 426.41,-26.5 415.93,-25.01 417.29,-31.88"/>
+</g>
+<!-- INT_MINDOTS -->
+<g id="node7" class="node">
+<title>INT_MINDOTS</title>
+<ellipse fill="lightblue" stroke="black" cx="68.51" cy="-216.25" rx="27" ry="18"/>
+<text text-anchor="middle" x="68.51" y="-211.2" font-family="Times New Roman,serif" font-size="14.00">...</text>
+</g>
+<!-- INT_TOP&#45;&gt;INT_MINDOTS -->
+<g id="edge5" class="edge">
+<title>INT_TOP&#45;&gt;INT_MINDOTS</title>
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+<polygon fill="black" stroke="black" points="97.5,-233.82 87.34,-230.81 93.41,-239.5 97.5,-233.82"/>
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+<!-- INT_ZERO -->
+<g id="node8" class="node">
+<title>INT_ZERO</title>
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+</g>
+<!-- INT_TOP&#45;&gt;INT_ZERO -->
+<g id="edge6" class="edge">
+<title>INT_TOP&#45;&gt;INT_ZERO</title>
+<path fill="none" stroke="black" d="M210.79,-310.12C200.2,-292 183.15,-262.82 170.98,-242.01"/>
+<polygon fill="black" stroke="black" points="174.12,-240.45 166.05,-233.58 168.08,-243.98 174.12,-240.45"/>
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+<!-- INT_MAXDOTS -->
+<g id="node9" class="node">
+<title>INT_MAXDOTS</title>
+<ellipse fill="lightblue" stroke="black" cx="244.51" cy="-216.25" rx="27" ry="18"/>
+<text text-anchor="middle" x="244.51" y="-211.2" font-family="Times New Roman,serif" font-size="14.00">...</text>
+</g>
+<!-- INT_TOP&#45;&gt;INT_MAXDOTS -->
+<g id="edge7" class="edge">
+<title>INT_TOP&#45;&gt;INT_MAXDOTS</title>
+<path fill="none" stroke="black" d="M224.26,-309.64C228.03,-292.44 233.9,-265.64 238.35,-245.33"/>
+<polygon fill="black" stroke="black" points="241.74,-246.23 240.46,-235.72 234.9,-244.73 241.74,-246.23"/>
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+<!-- INT_BOT -->
+<g id="node6" class="node">
+<title>INT_BOT</title>
+<ellipse fill="lightblue" stroke="black" cx="220.51" cy="-104.75" rx="33.95" ry="18"/>
+<text text-anchor="start" x="203.63" y="-100.7" font-family="Times New Roman,serif" font-weight="bold" font-size="14.00">⊥</text>
+<text text-anchor="start" x="219.38" y="-100.7" font-family="Times New Roman,serif" font-size="14.00">:int</text>
+</g>
+<!-- INT_BOT&#45;&gt;BOT -->
+<g id="edge11" class="edge">
+<title>INT_BOT&#45;&gt;BOT</title>
+<path fill="none" stroke="black" d="M248.01,-93.9C290.83,-78.57 373.15,-49.1 417.83,-33.11"/>
+<polygon fill="black" stroke="black" points="418.93,-36.43 427.17,-29.76 416.57,-29.84 418.93,-36.43"/>
+</g>
+<!-- INT_MINDOTS&#45;&gt;INT_BOT -->
+<g id="edge8" class="edge">
+<title>INT_MINDOTS&#45;&gt;INT_BOT</title>
+<path fill="none" stroke="black" d="M86.24,-202.47C112.22,-183.76 160.89,-148.7 191.95,-126.33"/>
+<polygon fill="black" stroke="black" points="193.68,-129.39 199.75,-120.71 189.59,-123.71 193.68,-129.39"/>
+</g>
+<!-- INT_MINDOTS&#45;&gt;INT_ZERO -->
+<!-- INT_ZERO&#45;&gt;INT_BOT -->
+<g id="edge9" class="edge">
+<title>INT_ZERO&#45;&gt;INT_BOT</title>
+<path fill="none" stroke="black" d="M165.14,-200.48C175.34,-183.02 192.52,-153.64 205.04,-132.22"/>
+<polygon fill="black" stroke="black" points="207.97,-134.13 210,-123.73 201.93,-130.6 207.97,-134.13"/>
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+<!-- INT_ZERO&#45;&gt;INT_MAXDOTS -->
+<!-- INT_MAXDOTS&#45;&gt;INT_BOT -->
+<g id="edge10" class="edge">
+<title>INT_MAXDOTS&#45;&gt;INT_BOT</title>
+<path fill="none" stroke="black" d="M240.76,-198.14C237.01,-181.04 231.18,-154.46 226.74,-134.19"/>
+<polygon fill="black" stroke="black" points="230.2,-133.6 224.64,-124.58 223.36,-135.09 230.2,-133.6"/>
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+<!-- PTR0 -->
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+<title>PTR0</title>
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+<polygon fill="green" stroke="none" points="342.51,-104.75 342.51,-127.25 378.51,-127.25 378.51,-104.75 342.51,-104.75"/>
+<polygon fill="none" stroke="black" points="342.51,-104.75 342.51,-127.25 378.51,-127.25 378.51,-104.75 342.51,-104.75"/>
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+<polygon fill="none" stroke="black" points="342.51,-82.25 342.51,-104.75 378.51,-104.75 378.51,-82.25 342.51,-82.25"/>
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+</g>
+<!-- PTR&#45;&gt;PTR0 -->
+<g id="edge15" class="edge">
+<title>PTR&#45;&gt;PTR0</title>
+<path fill="none" stroke="black" d="M360.51,-301.29C360.51,-261.89 360.51,-187.62 360.51,-142.52"/>
+<polygon fill="black" stroke="black" points="364.01,-142.68 360.51,-132.68 357.01,-142.68 364.01,-142.68"/>
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+<!-- PTR0&#45;&gt;BOT -->
+<g id="edge16" class="edge">
+<title>PTR0&#45;&gt;BOT</title>
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+<polygon fill="black" stroke="black" points="427.24,-46.63 432.19,-37.26 422.48,-41.5 427.24,-46.63"/>
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+<!-- STRUCT_S1 -->
+<g id="node14" class="node">
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+<stop offset="0" style="stop-color:lightblue;stop-opacity:1.;"/>
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+<text text-anchor="start" x="443.38" y="-211.2" font-family="Times New Roman,serif" font-size="14.00">int/ptr</text>
+</g>
+<!-- STRUCT_TOP&#45;&gt;STRUCT_S1 -->
+<g id="edge18" class="edge">
+<title>STRUCT_TOP&#45;&gt;STRUCT_S1</title>
+<path fill="none" stroke="black" d="M503.88,-310.12C492.57,-292.43 474.53,-264.21 461.3,-243.51"/>
+<polygon fill="black" stroke="black" points="464.39,-241.85 456.06,-235.31 458.49,-245.62 464.39,-241.85"/>
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+<!-- STRUCT_S2 -->
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+<title>STRUCT_S2</title>
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+<stop offset="0" style="stop-color:lightblue;stop-opacity:1.;"/>
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+<polygon fill="none" stroke="black" points="569.38,-216.25 569.38,-238.75 608.38,-238.75 608.38,-216.25 569.38,-216.25"/>
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+<polygon fill="none" stroke="black" points="538.63,-193.75 538.63,-216.25 569.38,-216.25 569.38,-193.75 538.63,-193.75"/>
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+<stop offset="0" style="stop-color:lightblue;stop-opacity:1.;"/>
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+</defs>
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+<text text-anchor="start" x="572.38" y="-199.95" font-family="Times New Roman,serif" font-size="14.00">int/ptr</text>
+</g>
+<!-- STRUCT_TOP&#45;&gt;STRUCT_S2 -->
+<g id="edge19" class="edge">
+<title>STRUCT_TOP&#45;&gt;STRUCT_S2</title>
+<path fill="none" stroke="black" d="M523.73,-309.64C531.97,-294.34 544.3,-271.45 554.63,-252.28"/>
+<polygon fill="black" stroke="black" points="557.59,-254.17 559.26,-243.7 551.43,-250.85 557.59,-254.17"/>
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+<!-- STRUCT_SN -->
+<g id="node16" class="node">
+<title>STRUCT_SN</title>
+<polygon fill="none" stroke="none" points="745.38,-254 659.63,-254 659.63,-178.5 745.38,-178.5 745.38,-254"/>
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+<polygon fill="none" stroke="black" points="667.63,-227.5 667.63,-250 698.38,-250 698.38,-227.5 667.63,-227.5"/>
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+<stop offset="0" style="stop-color:lightblue;stop-opacity:1.;"/>
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+<polygon fill="none" stroke="black" points="698.38,-227.5 698.38,-250 737.38,-250 737.38,-227.5 698.38,-227.5"/>
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+<polygon fill="none" stroke="black" points="667.63,-205 667.63,-227.5 698.38,-227.5 698.38,-205 667.63,-205"/>
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+</g>
+<!-- STRUCT_TOP&#45;&gt;STRUCT_SN -->
+<g id="edge20" class="edge">
+<title>STRUCT_TOP&#45;&gt;STRUCT_SN</title>
+<path fill="none" stroke="black" d="M539.09,-312.43C567.11,-296.11 613.72,-268.96 650.01,-247.82"/>
+<polygon fill="black" stroke="black" points="651.76,-250.85 658.64,-242.8 648.24,-244.81 651.76,-250.85"/>
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+<!-- STRUCT_BOT -->
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+<title>STRUCT_BOT</title>
+<ellipse fill="lightgreen" stroke="black" cx="512.51" cy="-104.75" rx="44.7" ry="18"/>
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+</g>
+<!-- STRUCT_BOT&#45;&gt;BOT -->
+<g id="edge24" class="edge">
+<title>STRUCT_BOT&#45;&gt;BOT</title>
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+<!-- STRUCT_S1&#45;&gt;STRUCT_BOT -->
+<g id="edge21" class="edge">
+<title>STRUCT_S1&#45;&gt;STRUCT_BOT</title>
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+<!-- STRUCT_S1&#45;&gt;STRUCT_S2 -->
+<!-- STRUCT_S2&#45;&gt;STRUCT_BOT -->
+<g id="edge22" class="edge">
+<title>STRUCT_S2&#45;&gt;STRUCT_BOT</title>
+<path fill="none" stroke="black" d="M559.36,-189.85C549.77,-172.63 537.12,-149.92 527.38,-132.44"/>
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+<!-- STRUCT_S2&#45;&gt;STRUCT_SN -->
+<!-- STRUCT_SN&#45;&gt;STRUCT_BOT -->
+<g id="edge23" class="edge">
+<title>STRUCT_SN&#45;&gt;STRUCT_BOT</title>
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+<!-- MEM_ALIAS1 -->
+<g id="node19" class="node">
+<title>MEM_ALIAS1</title>
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+<text text-anchor="middle" x="808.51" y="-211.2" font-family="Times New Roman,serif" font-size="14.00" fill="white">#1</text>
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+<!-- MEM_TOP&#45;&gt;MEM_ALIAS1 -->
+<g id="edge28" class="edge">
+<title>MEM_TOP&#45;&gt;MEM_ALIAS1</title>
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+<!-- MEM_ALIASDOTS -->
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+<!-- MEM_TOP&#45;&gt;MEM_ALIASDOTS -->
+<g id="edge29" class="edge">
+<title>MEM_TOP&#45;&gt;MEM_ALIASDOTS</title>
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+<!-- MEM_ALIASN -->
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+<!-- MEM_TOP&#45;&gt;MEM_ALIASN -->
+<g id="edge30" class="edge">
+<title>MEM_TOP&#45;&gt;MEM_ALIASN</title>
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+<!-- MEM_BOT -->
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+<ellipse fill="blue" stroke="black" cx="853.51" cy="-104.75" rx="43.67" ry="18"/>
+<text text-anchor="start" x="829.51" y="-100.7" font-family="Times New Roman,serif" font-weight="bold" font-size="14.00" fill="white">⊥</text>
+<text text-anchor="start" x="845.26" y="-100.7" font-family="Times New Roman,serif" font-size="14.00" fill="white">:mem</text>
+</g>
+<!-- MEM_BOT&#45;&gt;BOT -->
+<g id="edge34" class="edge">
+<title>MEM_BOT&#45;&gt;BOT</title>
+<path fill="none" stroke="black" d="M815.04,-96C735.55,-79.97 554.45,-43.48 480.68,-28.61"/>
+<polygon fill="black" stroke="black" points="481.37,-25.18 470.88,-26.63 479.99,-32.04 481.37,-25.18"/>
+</g>
+<!-- MEM_ALIAS1&#45;&gt;MEM_BOT -->
+<g id="edge31" class="edge">
+<title>MEM_ALIAS1&#45;&gt;MEM_BOT</title>
+<path fill="none" stroke="black" d="M815.94,-197.17C823.07,-179.82 833.93,-153.39 842.15,-133.4"/>
+<polygon fill="black" stroke="black" points="845.37,-134.75 845.94,-124.17 838.9,-132.09 845.37,-134.75"/>
+</g>
+<!-- MEM_ALIAS1&#45;&gt;MEM_ALIASDOTS -->
+<!-- MEM_ALIASDOTS&#45;&gt;MEM_BOT -->
+<g id="edge32" class="edge">
+<title>MEM_ALIASDOTS&#45;&gt;MEM_BOT</title>
+<path fill="none" stroke="black" d="M891.67,-198.62C884.58,-181.35 873.36,-154.05 864.92,-133.51"/>
+<polygon fill="black" stroke="black" points="868.17,-132.22 861.13,-124.3 861.7,-134.88 868.17,-132.22"/>
+</g>
+<!-- MEM_ALIASDOTS&#45;&gt;MEM_ALIASN -->
+<!-- MEM_ALIASN&#45;&gt;MEM_BOT -->
+<g id="edge33" class="edge">
+<title>MEM_ALIASN&#45;&gt;MEM_BOT</title>
+<path fill="none" stroke="black" d="M973.02,-202.69C950.75,-184.62 909.29,-151 881.55,-128.49"/>
+<polygon fill="black" stroke="black" points="883.86,-125.86 873.89,-122.28 879.45,-131.3 883.86,-125.86"/>
+</g>
+<!-- TUPLE1 -->
+<g id="node24" class="node">
+<title>TUPLE1</title>
+<polygon fill="none" stroke="none" points="1105.51,-242.75 1051.51,-242.75 1051.51,-189.75 1105.51,-189.75 1105.51,-242.75"/>
+<polygon fill="pink" stroke="none" points="1059.76,-216.25 1059.76,-238.75 1097.26,-238.75 1097.26,-216.25 1059.76,-216.25"/>
+<polygon fill="none" stroke="black" points="1059.76,-216.25 1059.76,-238.75 1097.26,-238.75 1097.26,-216.25 1059.76,-216.25"/>
+<text text-anchor="start" x="1062.76" y="-222.45" font-family="Times New Roman,serif" font-size="14.00">Tuple</text>
+<polygon fill="black" stroke="none" points="1059.76,-193.75 1059.76,-216.25 1097.26,-216.25 1097.26,-193.75 1059.76,-193.75"/>
+<polygon fill="none" stroke="black" points="1059.76,-193.75 1059.76,-216.25 1097.26,-216.25 1097.26,-193.75 1059.76,-193.75"/>
+<text text-anchor="start" x="1066.88" y="-199.95" font-family="Times New Roman,serif" font-size="14.00" fill="white">type</text>
+</g>
+<!-- TUPLE_TOP&#45;&gt;TUPLE1 -->
+<g id="edge38" class="edge">
+<title>TUPLE_TOP&#45;&gt;TUPLE1</title>
+<path fill="none" stroke="black" d="M1119.01,-309.64C1112.37,-294.48 1102.45,-271.87 1094.1,-252.81"/>
+<polygon fill="black" stroke="black" points="1097.35,-251.51 1090.13,-243.76 1090.94,-254.32 1097.35,-251.51"/>
+</g>
+<!-- TUPLE2 -->
+<g id="node25" class="node">
+<title>TUPLE2</title>
+<polygon fill="none" stroke="none" points="1202.51,-254 1148.51,-254 1148.51,-178.5 1202.51,-178.5 1202.51,-254"/>
+<polygon fill="pink" stroke="none" points="1156.76,-227.5 1156.76,-250 1194.26,-250 1194.26,-227.5 1156.76,-227.5"/>
+<polygon fill="none" stroke="black" points="1156.76,-227.5 1156.76,-250 1194.26,-250 1194.26,-227.5 1156.76,-227.5"/>
+<text text-anchor="start" x="1159.76" y="-233.7" font-family="Times New Roman,serif" font-size="14.00">Tuple</text>
+<polygon fill="black" stroke="none" points="1156.76,-205 1156.76,-227.5 1194.26,-227.5 1194.26,-205 1156.76,-205"/>
+<polygon fill="none" stroke="black" points="1156.76,-205 1156.76,-227.5 1194.26,-227.5 1194.26,-205 1156.76,-205"/>
+<text text-anchor="start" x="1163.88" y="-211.2" font-family="Times New Roman,serif" font-size="14.00" fill="white">type</text>
+<polygon fill="black" stroke="none" points="1156.76,-182.5 1156.76,-205 1194.26,-205 1194.26,-182.5 1156.76,-182.5"/>
+<polygon fill="none" stroke="black" points="1156.76,-182.5 1156.76,-205 1194.26,-205 1194.26,-182.5 1156.76,-182.5"/>
+<text text-anchor="start" x="1163.88" y="-188.7" font-family="Times New Roman,serif" font-size="14.00" fill="white">type</text>
+</g>
+<!-- TUPLE_TOP&#45;&gt;TUPLE2 -->
+<g id="edge39" class="edge">
+<title>TUPLE_TOP&#45;&gt;TUPLE2</title>
+<path fill="none" stroke="black" d="M1134.17,-309.64C1139.64,-297.4 1147.29,-280.3 1154.53,-264.14"/>
+<polygon fill="black" stroke="black" points="1157.68,-265.65 1158.57,-255.09 1151.3,-262.79 1157.68,-265.65"/>
+</g>
+<!-- TUPLEN -->
+<g id="node26" class="node">
+<title>TUPLEN</title>
+<polygon fill="none" stroke="none" points="1299.51,-265.25 1245.51,-265.25 1245.51,-167.25 1299.51,-167.25 1299.51,-265.25"/>
+<polygon fill="pink" stroke="none" points="1253.76,-238.75 1253.76,-261.25 1291.26,-261.25 1291.26,-238.75 1253.76,-238.75"/>
+<polygon fill="none" stroke="black" points="1253.76,-238.75 1253.76,-261.25 1291.26,-261.25 1291.26,-238.75 1253.76,-238.75"/>
+<text text-anchor="start" x="1256.76" y="-244.95" font-family="Times New Roman,serif" font-size="14.00">Tuple</text>
+<polygon fill="black" stroke="none" points="1253.76,-216.25 1253.76,-238.75 1291.26,-238.75 1291.26,-216.25 1253.76,-216.25"/>
+<polygon fill="none" stroke="black" points="1253.76,-216.25 1253.76,-238.75 1291.26,-238.75 1291.26,-216.25 1253.76,-216.25"/>
+<text text-anchor="start" x="1260.88" y="-222.45" font-family="Times New Roman,serif" font-size="14.00" fill="white">type</text>
+<polygon fill="black" stroke="none" points="1253.76,-193.75 1253.76,-216.25 1291.26,-216.25 1291.26,-193.75 1253.76,-193.75"/>
+<polygon fill="none" stroke="black" points="1253.76,-193.75 1253.76,-216.25 1291.26,-216.25 1291.26,-193.75 1253.76,-193.75"/>
+<text text-anchor="start" x="1266.88" y="-199.95" font-family="Times New Roman,serif" font-size="14.00" fill="white">...</text>
+<polygon fill="black" stroke="none" points="1253.76,-171.25 1253.76,-193.75 1291.26,-193.75 1291.26,-171.25 1253.76,-171.25"/>
+<polygon fill="none" stroke="black" points="1253.76,-171.25 1253.76,-193.75 1291.26,-193.75 1291.26,-171.25 1253.76,-171.25"/>
+<text text-anchor="start" x="1260.88" y="-177.45" font-family="Times New Roman,serif" font-size="14.00" fill="white">type</text>
+</g>
+<!-- TUPLE_TOP&#45;&gt;TUPLEN -->
+<g id="edge40" class="edge">
+<title>TUPLE_TOP&#45;&gt;TUPLEN</title>
+<path fill="none" stroke="black" d="M1146.81,-311.52C1169.97,-294.15 1208.28,-265.42 1236.53,-244.23"/>
+<polygon fill="black" stroke="black" points="1238.58,-247.07 1244.48,-238.27 1234.38,-241.47 1238.58,-247.07"/>
+</g>
+<!-- TUPLE_BOT -->
+<g id="node23" class="node">
+<title>TUPLE_BOT</title>
+<ellipse fill="pink" stroke="black" cx="1126.51" cy="-104.75" rx="42.65" ry="18"/>
+<text text-anchor="start" x="1103.26" y="-100.7" font-family="Times New Roman,serif" font-weight="bold" font-size="14.00">⊥</text>
+<text text-anchor="start" x="1119.01" y="-100.7" font-family="Times New Roman,serif" font-size="14.00">:tuple</text>
+</g>
+<!-- TUPLE_BOT&#45;&gt;BOT -->
+<g id="edge44" class="edge">
+<title>TUPLE_BOT&#45;&gt;BOT</title>
+<path fill="none" stroke="black" d="M1085.88,-98.86C962.25,-83.97 592.31,-39.44 480.72,-26"/>
+<polygon fill="black" stroke="black" points="481.43,-22.56 471.08,-24.84 480.59,-29.51 481.43,-22.56"/>
+</g>
+<!-- TUPLE1&#45;&gt;TUPLE_BOT -->
+<g id="edge41" class="edge">
+<title>TUPLE1&#45;&gt;TUPLE_BOT</title>
+<path fill="none" stroke="black" d="M1089.64,-189.85C1097.12,-172.8 1106.96,-150.34 1114.59,-132.93"/>
+<polygon fill="black" stroke="black" points="1117.61,-134.78 1118.41,-124.21 1111.19,-131.97 1117.61,-134.78"/>
+</g>
+<!-- TUPLE2&#45;&gt;TUPLE_BOT -->
+<g id="edge42" class="edge">
+<title>TUPLE2&#45;&gt;TUPLE_BOT</title>
+<path fill="none" stroke="black" d="M1159.19,-178.79C1152.51,-163.86 1144.92,-146.89 1138.73,-133.07"/>
+<polygon fill="black" stroke="black" points="1142.02,-131.83 1134.74,-124.13 1135.63,-134.69 1142.02,-131.83"/>
+</g>
+<!-- TUPLEN&#45;&gt;TUPLE_BOT -->
+<g id="edge43" class="edge">
+<title>TUPLEN&#45;&gt;TUPLE_BOT</title>
+<path fill="none" stroke="black" d="M1245.73,-195.16C1220.22,-176.03 1181.9,-147.29 1155.64,-127.59"/>
+<polygon fill="black" stroke="black" points="1157.86,-124.89 1147.76,-121.69 1153.66,-130.49 1157.86,-124.89"/>
+</g>
+</g>
+</svg>
diff --git a/src/main/java/com/seaofnodes/simple/GraphEvaluator.java b/src/main/java/com/seaofnodes/simple/GraphEvaluator.java
deleted file mode 100644
index 9fc51c8e..00000000
--- a/src/main/java/com/seaofnodes/simple/GraphEvaluator.java
+++ /dev/null
@@ -1,181 +0,0 @@
-package com.seaofnodes.simple;
-
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-
-import java.util.Arrays;
-import java.util.BitSet;
-import java.util.HashMap;
-
-public class GraphEvaluator {
-
- public enum ResultType { VALUE, FALLTHROUGH, TIMEOUT }
-
- public record Result(ResultType type, long value) {}
-
- /**
- * Find the start node from some node in the graph or null if there is no start node
- */
- private static StartNode findStart(BitSet visit, Node node) {
- if (node == null) return null;
- if (node instanceof StartNode start) return start;
- if( visit.get(node._nid) ) return null;
- visit.set(node._nid);
- for( Node def : node._inputs ) {
- var res = findStart(visit,def);
- if( res != null ) return res;
- }
- for( Node use : node._outputs ) {
- var res = findStart(visit,use);
- if( res != null ) return res;
- }
- return null;
- }
-
- /**
- * Find the control output from a control node
- */
- private static Node findControl(Node control) {
- for( Node use : control._outputs ) {
- if (use.isCFG()) return use;
- }
- return null;
- }
-
- /**
- * Find the projection for a node
- */
- private static ProjNode findProjection(Node node, int idx) {
- for( Node use : node._outputs ) {
- if (use instanceof ProjNode proj && proj._idx == idx) return proj;
- }
- return null;
- }
-
- /**
- * Cache values for phi and parameter projection nodes.
- */
- private final HashMap<Node, Long> cacheValues = new HashMap<>();
- /**
- * Cache for loop phis as they can depend on itself or other loop phis
- */
- private long[] loopPhiCache = new long[16];
-
- private GraphEvaluator() {
- }
-
- private long div(DivNode div) {
- long in2 = getValue(div.in(2));
- return in2 == 0 ? 0 : getValue(div.in(1)) / in2;
- }
-
- /**
- * Calculate the value of a node
- */
- private long getValue(Node node) {
- var cache = cacheValues.get(node);
- if (cache != null) return cache;
- return switch (node) {
- case ConstantNode cons -> ((TypeInteger)cons.compute()).value();
- case AddNode add -> getValue(add.in(1)) + getValue(add.in(2));
- case BoolNode.EQ eq -> getValue(eq.in(1)) == getValue(eq.in(2)) ? 1 : 0;
- case BoolNode.LE le -> getValue(le.in(1)) <= getValue(le.in(2)) ? 1 : 0;
- case BoolNode.LT lt -> getValue(lt.in(1)) < getValue(lt.in(2)) ? 1 : 0;
- case DivNode div -> div(div);
- case MinusNode minus -> -getValue(minus.in(1));
- case MulNode mul -> getValue(mul.in(1)) * getValue(mul.in(2));
- case NotNode not -> getValue(not.in(1)) == 0 ? 1 : 0;
- case SubNode sub -> getValue(sub.in(1)) - getValue(sub.in(2));
- default -> throw Utils.TODO("Unexpected node " + node);
- };
- }
-
- /**
- * Special case of latchPhis when phis can depend on phis of the same region.
- */
- private void latchLoopPhis(RegionNode region, Node prev) {
- int idx = Utils.find(region._inputs, prev);
- assert idx > 0;
- int i = 0;
- for( Node use : region._outputs ) {
- if (use instanceof PhiNode phi) {
- var value = getValue(phi.in(idx));
- if (i == loopPhiCache.length) loopPhiCache = Arrays.copyOf(loopPhiCache, loopPhiCache.length*2);
- loopPhiCache[i++] = value;
- }
- }
- i = 0;
- for( Node use : region._outputs ) {
- if (use instanceof PhiNode phi) cacheValues.put(phi, loopPhiCache[i++]);
- }
- }
-
- /**
- * Calculate the values of phis of the region and caches the values. The phis are not allowed to depend on other phis of the region.
- */
- private void latchPhis(RegionNode region, Node prev) {
- int idx = Utils.find(region._inputs, prev);
- assert idx > 0;
- for( Node use : region._outputs ) {
- if (use instanceof PhiNode phi) {
- var value = getValue(phi.in(idx));
- cacheValues.put(phi, value);
- }
- }
- }
-
- /**
- * Run the graph until either a return is found or the number of loop iterations are done.
- */
- private Result evaluate(StartNode start, long parameter, int loops) {
- var parameter1 = findProjection(start, 1);
- if (parameter1 != null) cacheValues.put(parameter1, parameter);
- Node control = findProjection(start, 0);
- Node prev = start;
- while (control != null) {
- Node next;
- switch (control) {
- case RegionNode region -> {
- if (region instanceof LoopNode && region.in(1) != prev) {
- if (loops--<=0) return new Result(ResultType.TIMEOUT, 0);
- latchLoopPhis(region, prev);
- } else {
- latchPhis(region, prev);
- }
- next = findControl(region);
- }
- case IfNode cond -> next = findProjection(cond, getValue(cond.in(1)) != 0 ? 0 : 1);
- case ReturnNode ret -> {
- return new Result(ResultType.VALUE, getValue(ret.in(1)));
- }
- case ProjNode ignored -> next = findControl(control);
- default -> throw Utils.TODO("Unexpected control node " + control);
- }
- prev = control;
- control = next;
- }
- return new Result(ResultType.FALLTHROUGH, 0);
- }
-
- public static long evaluate(Node graph) {
- return evaluate(graph, 0);
- }
-
- public static long evaluate(Node graph, long parameter) {
- return evaluate(graph, parameter, 1000);
- }
-
- public static long evaluate(Node graph, long parameter, int loops) {
- var res = evaluateWithResult(graph, parameter, loops);
- if (res.type== ResultType.TIMEOUT) throw new RuntimeException("Timeout");
- return res.value;
- }
-
- public static Result evaluateWithResult(Node graph, long parameter, int loops) {
- var start = findStart(new BitSet(), graph);
- if (start == null) return new Result(ResultType.TIMEOUT, 0);
- var evaluator = new GraphEvaluator();
- return evaluator.evaluate(start, parameter, loops);
- }
-
-}
diff --git a/src/main/java/com/seaofnodes/simple/GraphVisualizer.java b/src/main/java/com/seaofnodes/simple/GraphVisualizer.java
index b4d64d4c..cfe6d5cc 100644
--- a/src/main/java/com/seaofnodes/simple/GraphVisualizer.java
+++ b/src/main/java/com/seaofnodes/simple/GraphVisualizer.java
@@ -27,7 +27,7 @@ public class GraphVisualizer {
// nodes in the graph.
Collection<Node> all = findAll(stop, scope);
StringBuilder sb = new StringBuilder();
- sb.append("digraph chapter09 {\n");
+ sb.append("digraph chapter10 {\n");
sb.append("/*\n");
sb.append(stop._src);
sb.append("\n*/\n");
@@ -39,8 +39,10 @@ public class GraphVisualizer {
// still making the subgraphs DOT gets confused.
sb.append("\trankdir=BT;\n"); // Force Nodes before Scopes
+ // CNC - turned off Apr/8/2024, gives more flex in the layout and
+ // removes some of the more ludicrous layout choices.
// Preserve node input order
- sb.append("\tordering=\"in\";\n");
+ //sb.append("\tordering=\"in\";\n");
// Merge multiple edges hitting the same node. Makes common shared
// nodes much prettier to look at.
@@ -195,9 +197,14 @@ public class GraphVisualizer {
} else sb.append(def.uniqueName());
// Number edges, so we can see how they track
sb.append("[taillabel=").append(i);
+ // The edge from New to ctrl is just for anchoring the New
+ if ( n instanceof NewNode )
+ sb.append(" color=green");
// control edges are colored red
- if( def.isCFG() )
+ else if( def.isCFG() )
sb.append(" color=red");
+ else if( def.isMem() )
+ sb.append(" color=blue");
// Backedges do not add a ranking constraint
if( i==2 && (n instanceof PhiNode || n instanceof LoopNode) )
sb.append(" constraint=false");
diff --git a/src/main/java/com/seaofnodes/simple/IRPrinter.java b/src/main/java/com/seaofnodes/simple/IRPrinter.java
index c06ac9d0..f08f3208 100644
--- a/src/main/java/com/seaofnodes/simple/IRPrinter.java
+++ b/src/main/java/com/seaofnodes/simple/IRPrinter.java
@@ -2,14 +2,77 @@ package com.seaofnodes.simple;
import com.seaofnodes.simple.node.LoopNode;
import com.seaofnodes.simple.node.Node;
+import com.seaofnodes.simple.node.ProjNode;
import java.util.ArrayList;
import java.util.BitSet;
public class IRPrinter {
- // Another bulk pretty-printer. Makes more effort at basic-block grouping.
+ // Print a node on 1 line, columnar aligned, as:
+ // NNID NNAME DDEF DDEF [[ UUSE UUSE ]] TYPE
+ // 1234 sssss 1234 1234 1234 1234 1234 1234 tttttt
+ public static void _printLine( Node n, StringBuilder sb ) {
+ sb.append("%4d %-7.7s ".formatted(n._nid,n.label()));
+ if( n._inputs==null ) {
+ sb.append("DEAD\n");
+ return;
+ }
+ for( Node def : n._inputs )
+ sb.append(def==null ? "____ " : "%4d ".formatted(def._nid));
+ for( int i = n._inputs.size(); i<3; i++ )
+ sb.append(" ");
+ sb.append(" [[ ");
+ for( Node use : n._outputs )
+ sb.append(use==null ? "____ " : "%4d ".formatted(use._nid));
+ int lim = 5 - Math.max(n._inputs.size(),3);
+ for( int i = n._outputs.size(); i<lim; i++ )
+ sb.append(" ");
+ sb.append(" ]] ");
+ if( n._type!= null ) sb.append(n._type.str());
+ sb.append("\n");
+ }
+
+ private static StringBuilder nodeId(StringBuilder sb, Node n) {
+ sb.append("%%%d".formatted(n._nid));
+ if (n instanceof ProjNode proj) {
+ sb.append(".").append(proj._idx);
+ }
+ return sb;
+ }
+
+ // Print a node on 1 line, format is inspired by LLVM
+ // %id: TYPE = NODE(inputs ....)
+ // Nodes as referred to as %id
+ public static void _printLineLlvmFormat( Node n, StringBuilder sb ) {
+ nodeId(sb, n).append(": ");
+ if( n._inputs==null ) {
+ sb.append("DEAD\n");
+ return;
+ }
+ if( n._type!= null ) n._type.typeName(sb);
+ sb.append(" = ").append( n.label() ).append( "(" );
+ for( int i = 0; i < n._inputs.size(); i++ ) {
+ Node def = n.in(i);
+ if (i > 0)
+ sb.append(", ");
+ if (def == null) sb.append("_");
+ else nodeId(sb, def);
+ }
+ sb.append(")").append("\n");
+ }
+
+ public static void printLine( Node n, StringBuilder sb, boolean llvmFormat ) {
+ if (llvmFormat) _printLineLlvmFormat( n, sb );
+ else _printLine ( n, sb );
+ }
+
public static String prettyPrint(Node node, int depth) {
+ return prettyPrint( node, depth, false );
+ }
+
+ // Another bulk pretty-printer. Makes more effort at basic-block grouping.
+ public static String prettyPrint( Node node, int depth, boolean llvmFormat ) {
// First, a Breadth First Search at a fixed depth.
BFS bfs = new BFS(node,depth);
// Convert just that set to a post-order
@@ -24,16 +87,16 @@ public class IRPrinter {
Node n = rpos.get(i);
if( n.isCFG() || n.isMultiHead() ) {
if( !gap ) sb.append("\n"); // Blank before multihead
- n._printLine(sb); // Print head
+ printLine( n, sb, llvmFormat ); // Print head
while( --i >= 0 ) {
Node t = rpos.get(i);
if( !t.isMultiTail() ) { i++; break; }
- t._printLine(sb);
+ printLine( t, sb, llvmFormat );
}
sb.append("\n"); // Blank after multitail
gap = true;
} else {
- n._printLine( sb );
+ printLine( n, sb, llvmFormat );
gap = false;
}
}
diff --git a/src/main/java/com/seaofnodes/simple/IterPeeps.java b/src/main/java/com/seaofnodes/simple/IterPeeps.java
index 6dafd95f..1cee1ccb 100644
--- a/src/main/java/com/seaofnodes/simple/IterPeeps.java
+++ b/src/main/java/com/seaofnodes/simple/IterPeeps.java
@@ -1,8 +1,6 @@
package com.seaofnodes.simple;
-import com.seaofnodes.simple.node.ConstantNode;
-import com.seaofnodes.simple.node.Node;
-import com.seaofnodes.simple.node.StopNode;
+import com.seaofnodes.simple.node.*;
import java.util.ArrayList;
import java.util.Arrays;
@@ -90,6 +88,8 @@ public abstract class IterPeeps {
n.moveDepsToWorklist();
assert progressOnList(stop); // Very expensive assert
}
+ if( n.isUnused() && !(n instanceof StopNode) )
+ n.kill(); // Just plain dead
}
if( show )
diff --git a/src/main/java/com/seaofnodes/simple/Parser.java b/src/main/java/com/seaofnodes/simple/Parser.java
index aabdf63a..fc84c9d9 100644
--- a/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/src/main/java/com/seaofnodes/simple/Parser.java
@@ -45,14 +45,17 @@ public class Parser {
/**
* List of keywords disallowed as identifiers
*/
- private final HashSet<String> KEYWORDS = new HashSet<>(){{
+ private static final HashSet<String> KEYWORDS = new HashSet<>(){{
add("break");
add("continue");
add("else");
add("false");
add("if");
add("int");
+ add("new");
+ add("null");
add("return");
+ add("struct");
add("true");
add("while");
}};
@@ -67,9 +70,13 @@ public class Parser {
ScopeNode _continueScope;
ScopeNode _breakScope;
+ // Mapping from a Struct name to a Struct.
+ public static Map<String, TypeStruct> OBJS = new HashMap<>();
+
public Parser(String source, TypeInteger arg) {
Node.reset();
IterPeeps.reset();
+ OBJS.clear();
_lexer = new Lexer(source);
_scope = new ScopeNode();
_continueScope = _breakScope = null;
@@ -98,8 +105,8 @@ public class Parser {
_xScopes.push(_scope);
// Enter a new scope for the initial control and arguments
_scope.push();
- _scope.define(ScopeNode.CTRL, new ProjNode(START, 0, ScopeNode.CTRL).peephole());
- _scope.define(ScopeNode.ARG0, new ProjNode(START, 1, ScopeNode.ARG0).peephole());
+ _scope.define(ScopeNode.CTRL, Type.CONTROL , new ProjNode(START, 0, ScopeNode.CTRL).peephole());
+ _scope.define(ScopeNode.ARG0, TypeInteger.BOT, new ProjNode(START, 1, ScopeNode.ARG0).peephole());
parseBlock();
_scope.pop();
_xScopes.pop();
@@ -137,19 +144,61 @@ public class Parser {
* @return a {@link Node} or {@code null}
*/
private Node parseStatement() {
- if (matchx("return") ) return parseReturn();
- else if (matchx("int")) return parseDecl();
- else if (match ("{" )) return require(parseBlock(),"}");
- else if (matchx("if" )) return parseIf();
- else if (matchx("while")) return parseWhile();
- else if (matchx("break")) return parseBreak();
+ if( false ) return null;
+ else if (matchx("return") ) return parseReturn();
+ else if (matchx("int") ) return parseDecl(TypeInteger.BOT);
+ else if (match ("{") ) return require(parseBlock(),"}");
+ else if (matchx("if") ) return parseIf();
+ else if (matchx("while") ) return parseWhile();
+ else if (matchx("break") ) return parseBreak();
else if (matchx("continue")) return parseContinue();
+ else if (matchx("struct") ) return parseStruct();
else if (matchx("#showGraph")) return require(showGraph(),";");
- else if (matchx(";")) return null; // Empty statement
+ else if (matchx(";") ) return null; // Empty statement
+ // declarations of vars with struct type are handled in parseExpressionStatement due
+ // to ambiguity
else return parseExpressionStatement();
}
/**
+ * Parse a struct field.
+ * <pre>
+ * int IDENTIFIER ;
+ * </pre>
+ */
+ private Field parseField(String sname) {
+ if( matchx("int") ) // Currently only parsing "int" type fields
+ return require(Field.make(requireId().intern(),TypeInteger.BOT),";");
+ throw errorSyntax("A field type is expected, only type 'int' is supported at present");
+ }
+
+ /**
+ * Parse a struct declaration, and return the following statement.
+ * Only allowed in top level scope.
+ * Structs cannot be redefined.
+ *
+ * @return The statement following the struct
+ */
+ private Node parseStruct() {
+ if (_xScopes.size() > 1) throw errorSyntax("struct declarations can only appear in top level scope");
+ String typeName = requireId();
+ if ( OBJS.containsKey(typeName)) throw errorSyntax("struct '" + typeName + "' cannot be redefined");
+ ArrayList<Field> fields = new ArrayList<>();
+ require("{");
+ while (!peek('}') && !_lexer.isEOF()) {
+ Field field = parseField(typeName);
+ if (fields.contains(field)) throw errorSyntax("Field '" + field + "' already defined in struct '" + typeName + "'");
+ fields.add(field);
+ }
+ require("}");
+ // Build and install the TypeStruct
+ TypeStruct ts = TypeStruct.make(typeName, fields);
+ OBJS.put(typeName, ts); // Insert the struct name in the collection of all struct names
+ START.addMemProj(ts, _scope); // Insert memory edges
+ return parseStatement();
+ }
+
+ /**
* Parses a while statement
*
* <pre>
@@ -241,7 +290,7 @@ public class Parser {
cur.pop();
// If this is a continue then first time the target is null
// So we just use the pruned current scope as the base for the
- // continue
+ // "continue"
if (toScope == null)
return cur;
// toScope is either the break scope, or a scope that was created here
@@ -266,7 +315,7 @@ public class Parser {
private Node parseIf() {
require("(");
// Parse predicate
- var pred = require(parseExpression(), ")");
+ var pred = require(parseExpression(), ")").keep();
// IfNode takes current control and predicate
Node ifNode = new IfNode(ctrl(), pred).peephole();
// Setup projection nodes
@@ -280,6 +329,7 @@ public class Parser {
// Parse the true side
ctrl(ifT.unkeep()); // set ctrl token to ifTrue projection
+ _scope.upcast(ifT,pred,false); // Up-cast predicate
parseStatement(); // Parse true-side
ScopeNode tScope = _scope;
@@ -287,9 +337,11 @@ public class Parser {
_scope = fScope; // Restore scope, then parse else block if any
ctrl(ifF.unkeep()); // Ctrl token is now set to ifFalse projection
if (matchx("else")) {
+ _scope.upcast(ifF,pred,true); // Up-cast predicate
parseStatement();
fScope = _scope;
}
+ pred.unkeep();
if( tScope.nIns() != ndefs || fScope.nIns() != ndefs )
throw error("Cannot define a new name on one arm of an if");
@@ -313,7 +365,7 @@ public class Parser {
*/
private Node parseReturn() {
var expr = require(parseExpression(), ";");
- Node ret = STOP.addReturn(new ReturnNode(ctrl(), expr).peephole());
+ Node ret = STOP.addReturn(new ReturnNode(ctrl(), expr, _scope).peephole());
ctrl(new ConstantNode(Type.XCONTROL).peephole()); // Kill control
return ret;
}
@@ -328,40 +380,86 @@ public class Parser {
}
/**
- * Parses an expression statement
+ * Parses an expression statement or a declaration statement where type is a struct
*
* <pre>
- * name '=' expression ';'
+ * name; // Error
+ * type name; // Define name with default initial value
+ * type name = expr; // Define name with given initial value
+ * name = expr; // Reassign existing
+ * expr // Something else
* </pre>
* @return an expression {@link Node}, never {@code null}
*/
private Node parseExpressionStatement() {
- var name = requireId();
- require("=");
- var expr = require(parseExpression(), ";");
- if( _scope.update(name, expr)==null )
- throw error("Undefined name '" + name + "'");
+ int old = _lexer._position;
+ Type t = type();
+ String name = requireId();
+ Node expr;
+ if( match(";") ) { // Assign a default value
+ // No type and no expr is an error
+ if( t==null ) throw errorSyntax("expression");
+ expr = new ConstantNode(t.makeInit()).peephole();
+ } else if( match("=") ) { // Assign "= expr;"
+ expr = require(parseExpression(), ";");
+ } else { // Neither, so just a normal expression parse
+ _lexer._position = old;
+ return require(parseExpression(),";");
+ }
+
+ // Defining a new variable vs updating an old one
+ if( t != null ) {
+ if( _scope.define(name,t,expr) == null )
+ throw error("Redefining name '" + name + "'");
+ } else {
+ Node n = _scope.lookup(name);
+ t = _scope.lookupDeclaredType(name);
+ if( n==null )
+ throw error("Undefined name '" + name + "'");
+ _scope.update(name,expr);
+ }
+ if( !expr._type.isa(t) )
+ throw error("Type " + expr._type.str() + " is not of declared type " + t.str());
return expr;
}
+ // Parse a type-or-null
+ private Type type() {
+ int old = _lexer._position;
+ String tname = _lexer.matchId();
+ if( tname==null ) return null;
+ if( tname.equals("int") ) return TypeInteger.BOT;
+ TypeStruct obj = OBJS.get(tname);
+ if( obj != null )
+ return TypeMemPtr.make(obj,match("?"));
+ // Not a type; unwind the parse
+ _lexer._position = old;
+ return null;
+ }
+
/**
* Parses a declStatement
*
* <pre>
- * 'int' name = expression ';'
+ * type name = expression ';'
* </pre>
- * @return an expression {@link Node}, never {@code null}
+ * @return an expression {@link Node}
*/
- private Node parseDecl() {
- // Type is 'int' for now
+ private Node parseDecl(Type t) {
var name = requireId();
- require("=");
- var expr = require(parseExpression(), ";");
- if( _scope.define(name,expr) == null )
+ var expr = match(";")
+ // Assign a null value
+ ? new ConstantNode(t.makeInit()).peephole()
+ // Assign "= expr;"
+ : require(require("=").parseExpression(), ";");
+ if( !expr._type.isa(t) )
+ throw error("Type " + expr._type.str() + " is not of declared type " + t.str());
+ if( _scope.define(name,t,expr) == null )
throw error("Redefining name '" + name + "'");
return expr;
}
+
/**
* Parse an expression of the form:
*
@@ -448,20 +546,21 @@ public class Parser {
* Parse a unary minus expression.
*
* <pre>
- * unaryExpr : ('-') unaryExpr | primaryExpr
+ * unaryExpr : ('-') | '!') unaryExpr | postfixExpr | primaryExpr
* </pre>
* @return a unary expression {@link Node}, never {@code null}
*/
private Node parseUnary() {
if (match("-")) return new MinusNode(parseUnary()).peephole();
- return parsePrimary();
+ if (match("!")) return new NotNode(parseUnary()).peephole();
+ return parsePostfix(parsePrimary());
}
/**
* Parse a primary expression:
*
* <pre>
- * primaryExpr : integerLiteral | Identifier | true | false | '(' expression ')'
+ * primaryExpr : integerLiteral | Identifier | true | false | null | new Identifier | '(' expression ')'
* </pre>
* @return a primary {@link Node}, never {@code null}
*/
@@ -470,6 +569,13 @@ public class Parser {
if( match("(") ) return require(parseExpression(), ")");
if( matchx("true" ) ) return new ConstantNode(TypeInteger.constant(1)).peephole();
if( matchx("false") ) return new ConstantNode(TypeInteger.constant(0)).peephole();
+ if( matchx("null" ) ) return new ConstantNode(TypeMemPtr.NULLPTR).peephole();
+ if( matchx("new") ) {
+ String structName = requireId();
+ TypeStruct obj = OBJS.get(structName);
+ if( obj == null) throw errorSyntax("Unknown struct type '" + structName + "'");
+ return newStruct(obj);
+ }
String name = _lexer.matchId();
if( name == null) throw errorSyntax("an identifier or expression");
Node n = _scope.lookup(name);
@@ -478,6 +584,61 @@ public class Parser {
}
/**
+ * Return a NewNode but also generate instructions to initialize it.
+ */
+ private Node newStruct( TypeStruct obj ) {
+ Node n = new NewNode(TypeMemPtr.make(obj), ctrl()).peephole().keep();
+ Node initValue = new ConstantNode(TypeInteger.constant(0)).peephole();
+ int alias = START._aliasStarts.get(obj._name);
+ for( Field field : obj._fields ) {
+ memAlias(alias, new StoreNode(field._fname, alias, memAlias(alias), n, initValue).peephole());
+ alias++;
+ }
+ return n.unkeep();
+ }
+
+ // We set up memory aliases by inserting special vars in the scope these
+ // variables are prefixed by $ so they cannot be referenced in Simple code.
+ // Using vars has the benefit that all the existing machinery of scoping
+ // and phis work as expected
+ private Node memAlias(int alias ) { return _scope.lookup(memName(alias) ); }
+ private Node memAlias(int alias, Node st) { return _scope.update(memName(alias), st); }
+ public static String memName(int alias) { return ("$"+alias).intern(); }
+
+ /**
+ * Parse postfix expression. For now this is just a field
+ * expression, but in future could be array index too.
+ *
+ * <pre>
+ * expr ('.' IDENTIFIER)* [ = expr ]
+ * </pre>
+ */
+ private Node parsePostfix(Node expr) {
+ if( !match(".") ) return expr;
+
+ if( !(expr._type instanceof TypeMemPtr ptr) )
+ throw error("Expected struct reference but got " + expr._type.str());
+
+ String name = requireId().intern();
+ int idx = ptr._obj==null ? -1 : ptr._obj.find(name);
+ if( idx == -1 ) throw error("Accessing unknown field '" + name + "' from '" + ptr.str() + "'");
+ int alias = START._aliasStarts.get(ptr._obj._name)+idx;
+
+ if( match("=") ) {
+ // Disambiguate "obj.fld==x" boolean test from "obj.fld=x" field assignment
+ if( peek('=') ) _lexer._position--;
+ else {
+ Node val = parseExpression();
+ memAlias(alias, new StoreNode(name, alias, memAlias(alias), expr, val).peephole());
+ return expr; // "obj.a = expr" returns the expression while updating memory
+ }
+ }
+
+ Type declaredType = ptr._obj._fields[idx]._type;
+ return parsePostfix(new LoadNode(name, alias, declaredType, memAlias(alias), expr).peephole());
+ }
+
+ /**
* Parse integer literal
*
* <pre>
@@ -497,6 +658,7 @@ public class Parser {
private boolean matchx(String syntax) { return _lexer.matchx(syntax); }
// Return true and do NOT skip if 'ch' is next
private boolean peek(char ch) { return _lexer.peek(ch); }
+ private boolean peekIsId() { return _lexer.peekIsId(); }
// Require and return an identifier
private String requireId() {
@@ -505,9 +667,11 @@ public class Parser {
throw error("Expected an identifier, found '"+id+"'");
}
+
+
// Require an exact match
- private void require(String syntax) { require(null, syntax); }
- private <N extends Node> N require(N n, String syntax) {
+ private Parser require(String syntax) { require(null, syntax); return this; }
+ private <N> N require(N n, String syntax) {
if (match(syntax)) return n;
throw errorSyntax(syntax);
}
@@ -594,6 +758,8 @@ public class Parser {
return true;
}
+ // Match must be exact and not followed by more ID characters.
+ // Prevents identifier "ifxy" from matching an "if" statement.
boolean matchx(String syntax) {
if( !match(syntax) ) return false;
if( !isIdLetter(peek()) ) return true;
@@ -606,10 +772,14 @@ public class Parser {
return peek()==ch;
}
+ boolean peekIsId() {
+ skipWhiteSpace();
+ return isIdStart(peek());
+ }
+
// Return an identifier or null
String matchId() {
- skipWhiteSpace();
- return isIdStart(peek()) ? parseId() : null;
+ return peekIsId() ? parseId() : null;
}
// Used for errors
diff --git a/src/main/java/com/seaofnodes/simple/Utils.java b/src/main/java/com/seaofnodes/simple/Utils.java
index 45f15327..4f2af769 100644
--- a/src/main/java/com/seaofnodes/simple/Utils.java
+++ b/src/main/java/com/seaofnodes/simple/Utils.java
@@ -36,4 +36,30 @@ public class Utils {
return i;
return -1;
}
+ /**
+ * Search a list for an element by reference
+ *
+ * @param ary List to search in
+ * @param x Object to be searched
+ * @return >= 0 on success, -1 on failure
+ */
+ public static <E> int find( E[] ary, E x ) {
+ for( int i=0; i<ary.length; i++ )
+ if( ary[i]==x )
+ return i;
+ return -1;
+ }
+
+ // Rotate a long, nice for hashes
+ public static long rot( long x, int n ) { return (x<<n) | (x>>>n); }
+
+ // Fold a 64bit hash into 32 bits
+ public static int fold( long x ) { return (int)((x>>32) ^ x); }
+
+ public static boolean eq(String s0, String s1) {
+ if( s0==s1 ) return true;
+ assert s0==s0.intern();
+ assert s1==s1.intern();
+ return false;
+ }
}
diff --git a/src/main/java/com/seaofnodes/simple/node/AddNode.java b/src/main/java/com/seaofnodes/simple/node/AddNode.java
index 4e30bb55..2cc0b465 100644
--- a/src/main/java/com/seaofnodes/simple/node/AddNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/AddNode.java
@@ -132,7 +132,7 @@ public class AddNode extends Node {
for( int i=1; i<ns.length; i++ )
ns[i] = op.copy(lphi.in(i), rhs instanceof PhiNode ? rhs.in(i) : rhs).peephole();
String label = lphi._label + (rhs instanceof PhiNode rphi ? rphi._label : "");
- Node phi = new PhiNode(label,ns).peephole();
+ Node phi = new PhiNode(label,lphi._declaredType,ns).peephole();
// Rotate needs another op, otherwise just the phi
return lhs==lphi ? phi : op.copy(lhs.in(1),phi);
}
diff --git a/src/main/java/com/seaofnodes/simple/node/BoolNode.java b/src/main/java/com/seaofnodes/simple/node/BoolNode.java
index d3fcec95..9c15f01b 100644
--- a/src/main/java/com/seaofnodes/simple/node/BoolNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/BoolNode.java
@@ -2,6 +2,7 @@ package com.seaofnodes.simple.node;
import com.seaofnodes.simple.type.Type;
import com.seaofnodes.simple.type.TypeInteger;
+import com.seaofnodes.simple.type.TypeMemPtr;
import java.util.BitSet;
@@ -44,10 +45,25 @@ abstract public class BoolNode extends Node {
if( in(1)==in(2) )
return new ConstantNode(TypeInteger.constant(doOp(3,3)?1:0));
+ // Equals pushes constant to the right; 5==X becomes X==5.
+ if( this instanceof EQ ) {
+ if( !(in(2) instanceof ConstantNode) ) {
+ // con==noncon becomes noncon==con
+ if( in(1) instanceof ConstantNode )
+ return new EQ(in(2),in(1));
+ // Equals sorts by NID otherwise: non.high == non.low becomes non.low == non.high
+ else if( in(1)._nid > in(2)._nid )
+ return new EQ(in(2),in(1));
+ }
+ // Equals X==0 becomes a !X
+ if( (in(2)._type == TypeInteger.ZERO || in(2)._type == TypeMemPtr.NULLPTR) )
+ return new NotNode(in(1));
+ }
+
// Do we have ((x * (phi cons)) * con) ?
// Do we have ((x * (phi cons)) * (phi cons)) ?
// Push constant up through the phi: x * (phi con0*con0 con1*con1...)
- Node phicon = AddNode.phiCon(this,false);
+ Node phicon = AddNode.phiCon(this,this instanceof EQ);
if( phicon!=null ) return phicon;
return null;
diff --git a/src/main/java/com/seaofnodes/simple/node/CastNode.java b/src/main/java/com/seaofnodes/simple/node/CastNode.java
new file mode 100644
index 00000000..fec540f7
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/CastNode.java
@@ -0,0 +1,38 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeInteger;
+import com.seaofnodes.simple.IterPeeps;
+
+import java.util.BitSet;
+
+// Upcast (join) the input to a t. Used after guard test to lift an input.
+// Can also be used to make a type-assertion if ctrl is null.
+public class CastNode extends Node {
+ private final Type _t;
+ public CastNode(Type t, Node ctrl, Node in) {
+ super(ctrl, in);
+ _t = t;
+ setType(compute());
+ }
+
+ @Override public String label() { return "("+_t.str()+")"; }
+
+ @Override
+ public String uniqueName() { return "Cast_" + _nid; }
+
+ @Override
+ StringBuilder _print1(StringBuilder sb, BitSet visited) {
+ return in(1)._print0(sb.append(label()), visited);
+ }
+
+ @Override
+ public Type compute() {
+ return in(1)._type.join(_t);
+ }
+
+ @Override
+ public Node idealize() {
+ return in(1)._type.isa(_t) ? in(1) : null;
+ }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/ConstantNode.java b/src/main/java/com/seaofnodes/simple/node/ConstantNode.java
index d270cb29..d760c0df 100644
--- a/src/main/java/com/seaofnodes/simple/node/ConstantNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ConstantNode.java
@@ -51,8 +51,4 @@ public class ConstantNode extends Node {
@Override
int hash() { return _con.hashCode(); }
-
- // Dead control is its own idom root
- Node idom() { return null; }
-
}
diff --git a/src/main/java/com/seaofnodes/simple/node/IfNode.java b/src/main/java/com/seaofnodes/simple/node/IfNode.java
index 460dce51..1cf4ddaf 100644
--- a/src/main/java/com/seaofnodes/simple/node/IfNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/IfNode.java
@@ -1,15 +1,16 @@
package com.seaofnodes.simple.node;
+import com.seaofnodes.simple.IterPeeps;
import com.seaofnodes.simple.type.Type;
import com.seaofnodes.simple.type.TypeInteger;
import com.seaofnodes.simple.type.TypeTuple;
-
import java.util.BitSet;
public class IfNode extends MultiNode {
public IfNode(Node ctrl, Node pred) {
super(ctrl, pred);
+ IterPeeps.add(this); // Because idoms are complex, just add it
}
@Override
diff --git a/src/main/java/com/seaofnodes/simple/node/LoadNode.java b/src/main/java/com/seaofnodes/simple/node/LoadNode.java
new file mode 100644
index 00000000..53ae1096
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/LoadNode.java
@@ -0,0 +1,78 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.Field;
+
+import java.util.BitSet;
+
+/**
+ * Load represents extracting a value from inside a memory object,
+ * in chapter 10 this means Struct fields.
+ */
+public class LoadNode extends MemOpNode {
+
+ Type _declaredType;
+ /**
+ * Load a value from a ptr.field.
+ *
+ * @param name The field we are loading
+ * @param memSlice The memory alias node - this is updated after a Store
+ * @param memPtr The ptr to the struct from where we load a field
+ */
+ public LoadNode(String name, int alias, Type glb, Node memSlice, Node memPtr) {
+ super(name, alias, memSlice, memPtr, null);
+ _declaredType = glb;
+ }
+
+ @Override
+ public String label() { return "Load"; }
+
+ @Override
+ public String glabel() { return "."+_name; }
+
+ @Override
+ StringBuilder _print1(StringBuilder sb, BitSet visited) { return sb.append(".").append(_name); }
+
+ @Override
+ public Type compute() {
+ return _declaredType;
+ }
+
+ @Override
+ public Node idealize() {
+
+ // Simple Load-after-Store on same address.
+ if( mem() instanceof StoreNode st &&
+ ptr() == st.ptr() ) { // Must check same object
+ assert Utils.eq(_name,st._name); // Equiv class aliasing is perfect
+ return st.val();
+ }
+
+ // Push a Load up through a Phi, as long as it collapses on at least
+ // one arm. If at a Loop, the backedge MUST collapse - else we risk
+ // spinning the same transform around the loop indefinitely.
+ // BEFORE (2 Sts, 1 Ld): AFTER (1 St, 0 Ld):
+ // if( pred ) ptr.x = e0; val = pred ? e0
+ // else ptr.x = e1; : e1;
+ // val = ptr.x; ptr.x = val;
+ if( mem() instanceof PhiNode memphi && memphi.region()._type == Type.CONTROL && memphi.nIns()== 3 ) {
+ // Profit on RHS/Loop backedge
+ if( profit(memphi,2) ||
+ // Else must not be a loop to count profit on LHS.
+ (!(memphi.region() instanceof LoopNode) && profit(memphi,1)) ) {
+ Node ld1 = new LoadNode(_name,_alias,_declaredType,memphi.in(1),ptr()).peephole();
+ Node ld2 = new LoadNode(_name,_alias,_declaredType,memphi.in(2),ptr()).peephole();
+ return new PhiNode(_name,_type,memphi.region(),ld1,ld2);
+ }
+ }
+
+ return null;
+ }
+
+ // Profitable if we find a matching Store on this Phi arm.
+ private boolean profit(PhiNode phi, int idx) {
+ Node px = phi.in(idx);
+ return px!=null && px.addDep(this) instanceof StoreNode st1 && ptr()==st1.ptr();
+ }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/LoopNode.java b/src/main/java/com/seaofnodes/simple/node/LoopNode.java
index c192bc20..ea1489c4 100644
--- a/src/main/java/com/seaofnodes/simple/node/LoopNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/LoopNode.java
@@ -25,5 +25,7 @@ public class LoopNode extends RegionNode {
return inProgress() ? null : super.idealize();
}
+ // Bypass Region idom, same as the default idom() using use entry in(1) instead of in(0)
+ @Override int idepth() { return _idepth(1); }
@Override Node idom() { return entry(); }
}
diff --git a/src/main/java/com/seaofnodes/simple/node/MemOpNode.java b/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
new file mode 100644
index 00000000..08e08bbf
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
@@ -0,0 +1,40 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.type.Field;
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeMemPtr;
+
+/**
+ * Convenience common base for Load and Store.
+ */
+public abstract class MemOpNode extends Node {
+
+ public final String _name;
+ public final int _alias;
+
+ public MemOpNode(String name, int alias, Node memSlice, Node memPtr, Node value) {
+ super(null, memSlice, memPtr, value);
+ _name = name;
+ _alias = alias;
+ }
+
+ public Node mem() { return in(1); }
+ public Node ptr() { return in(2); }
+
+ @Override
+ boolean eq(Node n) {
+ MemOpNode mem = (MemOpNode)n; // Invariant
+ return _alias==mem._alias; // When comparing types error to use "equals"; always use "=="
+ }
+
+ @Override
+ int hash() { return _alias; }
+
+ @Override
+ String err() {
+ Type ptr = ptr()._type;
+ return (ptr==Type.BOTTOM || (ptr instanceof TypeMemPtr tmp && tmp._nil) )
+ ? "Might be null accessing '" + _name + "'"
+ : null;
+ }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/MinusNode.java b/src/main/java/com/seaofnodes/simple/node/MinusNode.java
index dd092c9e..9b687613 100644
--- a/src/main/java/com/seaofnodes/simple/node/MinusNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/MinusNode.java
@@ -26,5 +26,11 @@ public class MinusNode extends Node {
}
@Override
- public Node idealize() { return null; }
+ public Node idealize() {
+ // -(-x) is x
+ if( in(1) instanceof MinusNode minus )
+ return minus.in(1);
+
+ return null;
+ }
}
diff --git a/src/main/java/com/seaofnodes/simple/node/NewNode.java b/src/main/java/com/seaofnodes/simple/node/NewNode.java
new file mode 100644
index 00000000..352689b5
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/NewNode.java
@@ -0,0 +1,40 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeMemPtr;
+
+import java.util.BitSet;
+
+public class NewNode extends Node {
+
+ TypeMemPtr _ptr;
+
+ public NewNode(TypeMemPtr ptr, Node ctrl) {
+ super(ctrl);
+ this._ptr = ptr;
+ }
+
+ @Override
+ public String label() { return "new"; }
+
+ @Override
+ public String glabel() { return "new " + _ptr._obj._name; }
+
+ @Override
+ StringBuilder _print1(StringBuilder sb, BitSet visited) {
+ sb.append("new ");
+ return sb.append(_ptr._obj.str());
+ }
+
+ @Override
+ public Type compute() { return _ptr; }
+
+ @Override
+ public Node idealize() { return null; }
+
+ @Override
+ boolean eq(Node n) { return this == n; }
+
+ @Override
+ int hash() { return _ptr.hashCode(); }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/Node.java b/src/main/java/com/seaofnodes/simple/node/Node.java
index a5f26545..c4889231 100644
--- a/src/main/java/com/seaofnodes/simple/node/Node.java
+++ b/src/main/java/com/seaofnodes/simple/node/Node.java
@@ -51,15 +51,6 @@ public abstract class Node {
/**
- * Immediate dominator tree depth, used to approximate a real IDOM during
- * parsing where we do not have the whole program, and also peepholes
- * change the CFG incrementally.
- * <p>
- * See {@link <a href="https://en.wikipedia.org/wiki/Dominator_(graph_theory)">...</a>}
- */
- int _idepth;
-
- /**
* A private Global Static mutable counter, for unique node id generation.
* To make the compiler multithreaded, this field will have to move into a TLS.
* Starting with value 1, to avoid bugs confusing node ID 0 with uninitialized values.
@@ -81,7 +72,11 @@ public abstract class Node {
public abstract String label();
// Unique label for graph visualization, e.g. "Add12" or "Region30" or "EQ99"
- public String uniqueName() { return label() + _nid; }
+ public String uniqueName() {
+ // Get rid of $ as graphviz doesn't like it
+ String label = label().replaceAll("\\$", "");
+ return label + _nid;
+ }
// Graphical label, e.g. "+" or "Region" or "=="
public String glabel() { return label(); }
@@ -118,31 +113,6 @@ public abstract class Node {
// Every Node implements this; a partial-line recursive print
abstract StringBuilder _print1(StringBuilder sb, BitSet visited);
-
- // Print a node on 1 line, columnar aligned, as:
- // NNID NNAME DDEF DDEF [[ UUSE UUSE ]] TYPE
- // 1234 sssss 1234 1234 1234 1234 1234 1234 tttttt
- public void _printLine(StringBuilder sb ) {
- sb.append("%4d %-7.7s ".formatted(_nid,label()));
- if( _inputs==null ) {
- sb.append("DEAD\n");
- return;
- }
- for( Node def : _inputs )
- sb.append(def==null ? "____ " : "%4d ".formatted(def._nid));
- for( int i = _inputs.size(); i<3; i++ )
- sb.append(" ");
- sb.append(" [[ ");
- for( Node use : _outputs )
- sb.append(use==null ? "____ " : "%4d ".formatted(use._nid));
- int lim = 5 - Math.max(_inputs.size(),3);
- for( int i = _outputs.size(); i<lim; i++ )
- sb.append(" ");
- sb.append(" ]] ");
- if( _type!= null ) _type.print(sb);
- sb.append("\n");
- }
-
public String p(int depth) { return IRPrinter.prettyPrint(this,depth); }
public boolean isMultiHead() { return false; }
@@ -167,6 +137,8 @@ public abstract class Node {
public boolean isCFG() { return false; }
+ public boolean isMem() { return false; }
+
/**
* Change a <em>def</em> into a Node. Keeps the edges correct, by removing
* the corresponding <em>use->def</em> edge. This may make the original
@@ -197,6 +169,7 @@ public abstract class Node {
old_def.kill(); // Kill old def
// Set the new_def over the old (killed) edge
_inputs.set(idx,new_def);
+ moveDepsToWorklist();
// Return self for easy flow-coding
return new_def;
}
@@ -284,6 +257,8 @@ public abstract class Node {
public <N extends Node> N keep() { addUse(null); return (N)this; }
// Remove bogus null.
public <N extends Node> N unkeep() { delUse(null); return (N)this; }
+ // Test "keep" status
+ public boolean iskeep() { return Utils.find(_outputs,null) != -1; }
// Replace self with nnn in the graph, making 'this' go dead
@@ -345,7 +320,7 @@ public abstract class Node {
Type old = setType(compute());
// Replace constant computations from non-constants with a constant node
- if (!(this instanceof ConstantNode) && _type.isHighOrConst() )
+ if( !(this instanceof ConstantNode) && _type.isHighOrConst() )
return new ConstantNode(_type).peepholeOpt();
// Global Value Numbering
@@ -380,7 +355,7 @@ public abstract class Node {
private Node deadCodeElim(Node m) {
// If self is going dead and not being returned here (Nodes returned
// from peephole commonly have no uses (yet)), then kill self.
- if( m != this && isUnused() ) {
+ if( m != this && isUnused() && !isDead() ) {
// Killing self - and since self recursively kills self's inputs we
// might end up killing 'm', which we are returning as a live Node.
// So we add a bogus extra null output edge to stop kill().
@@ -478,9 +453,9 @@ public abstract class Node {
ArrayList<Node> _deps;
/**
- * Add a node to the list o dependencies. Only add it if its not
- * an input or output of this node, that is, it is at least one step
- * away. The node being added must benefit from this node being peepholed.
+ * Add a node to the list of dependencies. Only add it if its not an input
+ * or output of this node, that is, it is at least one step away. The node
+ * being added must benefit from this node being peepholed.
*/
Node addDep( Node dep ) {
// Running peepholes during the big assert cannot have side effects
@@ -567,14 +542,11 @@ public abstract class Node {
}
/**
- * Does this node contain all constants?
- * Ignores in(0), as is usually control.
- * In an input is not a constant, we add dep as
- * a dependency to it, because dep can make progress
- * if the input becomes a constant later.
- * It is sufficient for one of the non-const
- * inputs to have the dependency so we don't bother
- * checking the rest.
+ * Does this node contain all constants? Ignores in(0), as is usually
+ * control. In an input is not a constant, we add dep as a dependency to
+ * it because dep can make progress if the input becomes a constant later.
+ * It is sufficient for one of the non-const inputs to have the dependency,
+ * so we don't bother checking the rest.
*/
boolean allCons(Node dep) {
for( int i=1; i<nIns(); i++ )
@@ -585,19 +557,29 @@ public abstract class Node {
return true;
}
- // Return the immediate dominator of this Node and compute dom tree depth.
- Node idom() {
- Node idom = in(0);
- if( idom._idepth==0 ) idom.idom(); // Recursively set _idepth
- if( _idepth==0 ) _idepth = idom._idepth+1;
- return idom;
- }
+
+ /**
+ * Immediate dominator tree depth, used to approximate a real IDOM depth
+ * during parsing where we do not have the whole program, and also
+ * peepholes change the CFG incrementally.
+ * <p>
+ * See {@link <a href="https://en.wikipedia.org/wiki/Dominator_(graph_theory)">...</a>}
+ */
+ public int _idepth; // IDOM depth approx; Zero is unset; non-zero is cached legit
+ final int _idepth(int idx) { return _idepth==0 ? (_idepth=in(idx).idepth()+1) : _idepth; }
+ int idepth() { return _idepth(0); }
+
+ // Return the immediate dominator of this Node.
+ Node idom() { return in(0); }
// Make a shallow copy (same class) of this Node, with given inputs and
// empty outputs and a new Node ID. The original inputs are ignored.
// Does not need to be implemented in isCFG() nodes.
Node copy(Node lhs, Node rhs) { throw Utils.TODO("Binary ops need to implement copy"); }
+ // Report any post-optimize errors
+ String err() { return null; }
+
/**
* Used to allow repeating tests in the same JVM. This just resets the
* Node unique id generator, and is done as part of making a new Parser.
diff --git a/src/main/java/com/seaofnodes/simple/node/NotNode.java b/src/main/java/com/seaofnodes/simple/node/NotNode.java
index 7a520fec..05e44eb0 100644
--- a/src/main/java/com/seaofnodes/simple/node/NotNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/NotNode.java
@@ -1,8 +1,7 @@
package com.seaofnodes.simple.node;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.type.*;
import java.util.BitSet;
public class NotNode extends Node {
@@ -20,9 +19,24 @@ public class NotNode extends Node {
@Override
public Type compute() {
- if( in(1)._type instanceof TypeInteger i0 )
+ Type t0 = in(1)._type;
+ switch( t0 ) {
+ case TypeInteger i0:
return i0.isConstant() ? TypeInteger.constant(i0.value()==0 ? 1 : 0) : i0;
- return TypeInteger.TOP.meet(in(1)._type);
+ case TypeMemPtr p0:
+ // top->top, bot->bot, null->1, *void->0, not-null ptr->0, ptr/nil->bot
+ // If input in null then true
+ // If input is not null ptr then false
+ if( p0 == TypeMemPtr.TOP ) return TypeInteger.TOP;
+ if( p0 == TypeMemPtr.NULLPTR ) return TypeInteger.constant(1);
+ if( !p0._nil ) return TypeInteger.constant(0);
+ return TypeInteger.BOT;
+ case Type t:
+ if( t0.getClass() != Type.class )
+ // Only doing NOT on ints and ptrs
+ throw Utils.TODO();
+ return t0==Type.TOP ? Type.TOP : Type.BOTTOM;
+ }
}
@Override
diff --git a/src/main/java/com/seaofnodes/simple/node/PhiNode.java b/src/main/java/com/seaofnodes/simple/node/PhiNode.java
index ec4c6ad3..dd67bd06 100644
--- a/src/main/java/com/seaofnodes/simple/node/PhiNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/PhiNode.java
@@ -1,6 +1,8 @@
package com.seaofnodes.simple.node;
import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeMem;
+import com.seaofnodes.simple.Utils;
import java.util.BitSet;
@@ -8,7 +10,11 @@ public class PhiNode extends Node {
final String _label;
- public PhiNode(String label, Node... inputs) { super(inputs); _label = label; }
+ // The Phi type we compute must stay within the domain of the Phi.
+ // Example Int stays Int, Ptr stays Ptr, Control stays Control, Mem stays Mem.
+ final Type _declaredType;
+
+ public PhiNode(String label, Type declaredType, Node... inputs) { super(inputs); _label = label; assert declaredType!=null; _declaredType = declaredType; }
@Override public String label() { return "Phi_"+_label; }
@@ -31,17 +37,21 @@ public class PhiNode extends Node {
Node region() { return in(0); }
@Override public boolean isMultiTail() { return true; }
+ @Override
+ public boolean isMem() { return _declaredType instanceof TypeMem; }
@Override
public Type compute() {
if( !(region() instanceof RegionNode r) )
return region()._type==Type.XCONTROL ? Type.TOP : _type;
- if( r.inProgress() ) return Type.BOTTOM;
- Type t = Type.TOP;
+ // During parsing Phis have to be computed type pessimistically.
+ if( r.inProgress() ) return _declaredType;
+ // Set type to local top of the starting type
+ Type t = _declaredType.glb().dual();
for (int i = 1; i < nIns(); i++)
// If the region's control input is live, add this as a dependency
// to the control because we can be peeped should it become dead.
- if( r.in(i).addDep(this)._type != Type.XCONTROL && in(i) != this )
+ if( r.in(i).addDep(this)._type != Type.XCONTROL )
t = t.meet(in(i)._type);
return t;
}
@@ -71,11 +81,35 @@ public class PhiNode extends Node {
lhss[i] = in(i).in(1);
rhss[i] = in(i).in(2);
}
- Node phi_lhs = new PhiNode(_label,lhss).peephole();
- Node phi_rhs = new PhiNode(_label,rhss).peephole();
+ Node phi_lhs = new PhiNode(_label, _declaredType,lhss).peephole();
+ Node phi_rhs = new PhiNode(_label, _declaredType,rhss).peephole();
return op.copy(phi_lhs,phi_rhs);
}
+ // If merging Phi(N, cast(N)) - we are losing the cast JOIN effects, so just remove.
+ if( nIns()==3 ) {
+ if( in(1) instanceof CastNode cast && cast.in(1).addDep(this)==in(2) ) return in(2);
+ if( in(2) instanceof CastNode cast && cast.in(1).addDep(this)==in(1) ) return in(1);
+ }
+ // If merging a null-checked null and the checked value, just use the value.
+ // if( val ) ..; phi(Region,False=0/null,True=val);
+ // then replace with plain val.
+ if( nIns()==3 ) {
+ int nullx = -1;
+ if( in(1)._type == in(1)._type.makeInit() ) nullx = 1;
+ if( in(2)._type == in(2)._type.makeInit() ) nullx = 2;
+ if( nullx != -1 ) {
+ Node val = in(3-nullx);
+ if( region().idom() instanceof IfNode iff && iff.pred().addDep(this)==val ) {
+ // Must walk the idom on the null side to make sure we hit False.
+ Node idom = region().in(nullx);
+ while( idom.in(0) != iff ) idom = idom.idom();
+ if( idom instanceof ProjNode proj && proj._idx==1 )
+ return val;
+ }
+ }
+ }
+
return null;
}
diff --git a/src/main/java/com/seaofnodes/simple/node/ProjNode.java b/src/main/java/com/seaofnodes/simple/node/ProjNode.java
index 0ed9441d..735fcdf3 100644
--- a/src/main/java/com/seaofnodes/simple/node/ProjNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ProjNode.java
@@ -1,6 +1,7 @@
package com.seaofnodes.simple.node;
import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeMem;
import com.seaofnodes.simple.type.TypeTuple;
import java.util.BitSet;
@@ -27,6 +28,7 @@ public class ProjNode extends Node {
@Override public boolean isCFG() { return _idx==0 || ctrl() instanceof IfNode; }
@Override public boolean isMultiTail() { return in(0).isMultiHead(); }
+ @Override public boolean isMem() { return _type instanceof TypeMem; }
public MultiNode ctrl() { return (MultiNode)in(0); }
@@ -38,8 +40,14 @@ public class ProjNode extends Node {
@Override
public Node idealize() {
- if( ctrl()._type instanceof TypeTuple tt && tt._types[1-_idx]==Type.XCONTROL ) // Only true for IfNodes
- return ctrl().in(0); // We become our input control
+ if ( ctrl() instanceof IfNode iff ) {
+ if ( iff._type instanceof TypeTuple tt && tt._types[1 - _idx] == Type.XCONTROL )
+ return iff.in(0); // We become our input control
+
+ // Flip a negating if-test, to remove the not
+ if( iff.pred().addDep(this) instanceof NotNode not )
+ return new ProjNode((MultiNode)new IfNode(iff.ctrl(),not.in(1)).peephole(),1-_idx,_idx==0 ? "False" : "True");
+ }
return null;
}
diff --git a/src/main/java/com/seaofnodes/simple/node/RegionNode.java b/src/main/java/com/seaofnodes/simple/node/RegionNode.java
index c949c2b2..42501118 100644
--- a/src/main/java/com/seaofnodes/simple/node/RegionNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/RegionNode.java
@@ -35,6 +35,7 @@ public class RegionNode extends Node {
@Override
public Node idealize() {
if( inProgress() ) return null;
+ // Delete dead paths into a Region
int path = findDeadInput();
if( path != 0 &&
// Do not delete the entry path of a loop (ok to remove the back
@@ -51,17 +52,25 @@ public class RegionNode extends Node {
while( nouts != nOuts() ) {
nouts = nOuts();
for( int i=0; i<nOuts(); i++ )
- if( out(i) instanceof PhiNode phi && phi.nIns()==nIns() )
+ if( out(i) instanceof PhiNode phi && phi.nIns()==nIns() ) {
phi.delDef(path);
+ IterPeeps.addAll(phi._outputs);
+ }
}
- _idom = null; // Clear idom cache
return isDead() ? new ConstantNode(Type.XCONTROL) : delDef(path);
}
// If down to a single input, become that input
- if( nIns()==2 && !hasPhi() ) {
- _idom = null; // Clear idom cache
+ if( nIns()==2 && !hasPhi() )
return in(1); // Collapse if no Phis; 1-input Phis will collapse on their own
- }
+
+ // If a CFG diamond with no merging, delete: "if( pred ) {} else {};"
+ if( !hasPhi() && // No Phi users, just a control user
+ in(1) instanceof ProjNode p1 &&
+ in(2) instanceof ProjNode p2 &&
+ p1.in(0)==p2.in(0) &&
+ p1.in(0) instanceof IfNode iff )
+ return iff.ctrl();
+
return null;
}
@@ -80,26 +89,28 @@ public class RegionNode extends Node {
}
// Immediate dominator of Region is a little more complicated.
- private Node _idom; // Immediate dominator cache
+ @Override int idepth() {
+ if( _idepth!=0 ) return _idepth;
+ int d=0;
+ for( Node n : _inputs )
+ if( n!=null )
+ d = Math.max(d,n.idepth());
+ return _idepth=d;
+ }
+
@Override Node idom() {
- if( _idom != null ) {
- if( _idom.isDead() ) _idom=null;
- else return _idom; // Return cached copy
- }
if( nIns()==2 ) return in(1); // 1-input is that one input
if( nIns()!=3 ) return null; // Fails for anything other than 2-inputs
- // Walk the LHS & RHS idom trees in parallel until they match, or either fails
- Node lhs = in(1).idom();
- Node rhs = in(2).idom();
+ // Walk the LHS & RHS idom trees in parallel until they match, or either fails.
+ // Because this does not cache, it can be linear in the size of the program.
+ Node lhs = in(1);
+ Node rhs = in(2);
while( lhs != rhs ) {
if( lhs==null || rhs==null ) return null;
- var comp = lhs._idepth - rhs._idepth;
+ var comp = lhs.idepth() - rhs.idepth();
if( comp >= 0 ) lhs = lhs.idom();
if( comp <= 0 ) rhs = rhs.idom();
}
- if( lhs==null ) return null;
- _idepth = lhs._idepth+1;
- if( !IterPeeps.midAssert() ) _idom=lhs;
return lhs;
}
diff --git a/src/main/java/com/seaofnodes/simple/node/ReturnNode.java b/src/main/java/com/seaofnodes/simple/node/ReturnNode.java
index 922a3649..92bda5bf 100644
--- a/src/main/java/com/seaofnodes/simple/node/ReturnNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ReturnNode.java
@@ -15,8 +15,15 @@ import java.util.BitSet;
*/
public class ReturnNode extends Node {
- public ReturnNode(Node ctrl, Node data) {
+ public ReturnNode(Node ctrl, Node data, ScopeNode scope) {
super(ctrl, data);
+ // We lookup memory slices by the naming convention that they start with $
+ // We could also use implicit knowledge that all memory projects are at offset >= 2
+ String[] names = scope.reverseNames();
+ for (String name: names) {
+ if (!name.equals("$ctrl") && name.startsWith("$"))
+ addDef(scope.lookup(name));
+ }
}
public Node ctrl() { return in(0); }
@@ -27,7 +34,9 @@ public class ReturnNode extends Node {
@Override
StringBuilder _print1(StringBuilder sb, BitSet visited) {
- return expr()._print0(sb.append("return "), visited).append(";");
+ sb.append("return ");
+ expr()._print0(sb, visited);
+ return sb.append(";");
}
@Override public boolean isCFG() { return true; }
diff --git a/src/main/java/com/seaofnodes/simple/node/ScopeNode.java b/src/main/java/com/seaofnodes/simple/node/ScopeNode.java
index 3abea54d..843ce733 100644
--- a/src/main/java/com/seaofnodes/simple/node/ScopeNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ScopeNode.java
@@ -2,6 +2,8 @@ package com.seaofnodes.simple.node;
import com.seaofnodes.simple.IterPeeps;
import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.type.TypeMemPtr;
import java.util.*;
@@ -23,10 +25,16 @@ public class ScopeNode extends Node {
*/
public final Stack<HashMap<String, Integer>> _scopes;
+ /**
+ * Tracks declared types for every name
+ */
+ public Stack<HashMap<String, Type>> _types;
+
// A new ScopeNode
public ScopeNode() {
_scopes = new Stack<>();
+ _types = new Stack<>();
_type = Type.BOTTOM;
}
@@ -69,14 +77,15 @@ public class ScopeNode extends Node {
@Override public Node idealize() { return null; }
- public void push() { _scopes.push(new HashMap<>()); }
- public void pop() { popN(_scopes.pop().size()); }
+ public void push() { _scopes.push(new HashMap<>()); _types.push(new HashMap<>()); }
+ public void pop() { popN(_scopes.pop().size()); _types.pop(); }
/**
* Create a new name in the current scope
*/
- public Node define( String name, Node n ) {
+ public Node define( String name, Type declaredType, Node n ) {
HashMap<String,Integer> syms = _scopes.lastElement();
+ _types.lastElement().put(name,declaredType);
if( syms.put(name,nIns()) != null )
return null; // Double define
return addDef(n);
@@ -97,7 +106,7 @@ public class ScopeNode extends Node {
public Node update( String name, Node n ) { return update(name,n,_scopes.size()-1); }
/**
* Both recursive lookup and update.
- *
+ * <p>
* A shared implementation allows us to create lazy phis both during
* lookups and updates; the lazy phi creation is part of chapter 8.
*
@@ -120,12 +129,21 @@ public class ScopeNode extends Node {
// Set real Phi in the loop head
// The phi takes its one input (no backedge yet) from a recursive
// lookup, which might have insert a Phi in every loop nest.
- : loop.setDef(idx,new PhiNode(name,loop.ctrl(),loop.update(name,null,nestingLevel),null).peephole());
+ : loop.setDef(idx,new PhiNode(name, lookupDeclaredType(name),loop.ctrl(),loop.update(name,null,nestingLevel),null).peephole());
setDef(idx,old);
}
return n==null ? old : setDef(idx,n); // Not lazy, so this is the answer
}
+ // Return declared type
+ public Type lookupDeclaredType( String name ) {
+ for( int i=_types.size(); i>0; i-- ) {
+ Type t = _types.get(i-1).get(name);
+ if( t != null ) return t;
+ }
+ return null;
+ }
+
public Node ctrl() { return in(0); }
/**
@@ -162,8 +180,10 @@ public class ScopeNode extends Node {
// 3) Ensure that the order of defs is the same to allow easy merging
for( HashMap<String,Integer> syms : _scopes )
dup._scopes.push(new HashMap<>(syms));
+ for( HashMap<String,Type> ts : _types )
+ dup._types.push(ts); // Types don't change, just keep stacks aligned
- dup.addDef(ctrl()); // Control input is just copied
+ dup.addDef(ctrl()); // Control input is just copied
for( int i=1; i<nIns(); i++ )
// For lazy phis on loops we use a sentinel
// that will trigger phi creation on update
@@ -187,8 +207,9 @@ public class ScopeNode extends Node {
if( in(i) != that.in(i) ) // No need for redundant Phis
// If we are in lazy phi mode we need to a lookup
// by name as it will trigger a phi creation
- setDef(i, new PhiNode(ns[i], r, this.lookup(ns[i]), that.lookup(ns[i])).peephole());
+ setDef(i, new PhiNode(ns[i], this.lookupDeclaredType(ns[i]), r, this.lookup(ns[i]), that.lookup(ns[i])).peephole());
that.kill(); // Kill merged scope
+ IterPeeps.add(r);
return r.unkeep().peephole();
}
@@ -216,11 +237,61 @@ public class ScopeNode extends Node {
IterPeeps.addAll(phi._outputs);
phi.moveDepsToWorklist();
if( in != phi ) {
- phi.subsume(in);
+ if( !phi.iskeep() ) // Keeping phi around for parser elsewhere
+ phi.subsume(in);
setDef(i,in); // Set the update back into Scope
}
}
}
}
+
+
+ // Up-casting: using the results of an If to improve a value.
+ // E.g. "if( ptr ) ptr.field;" is legal because ptr is known not-null.
+
+ // This Scope looks for direct variable uses, or certain simple
+ // combinations, and replaces the variable with the upcast variant.
+ public Node upcast( Node ctrl, Node pred, boolean invert ) {
+ if( ctrl._type==Type.XCONTROL ) return null;
+ // Invert the If conditional
+ if( invert )
+ pred = pred instanceof NotNode not ? not.in(1) : IterPeeps.add(new NotNode(pred).peephole());
+
+ // Direct use of a value as predicate. This is a zero/null test.
+ if( Utils.find(_inputs, pred) != -1 ) {
+ if( !(pred._type instanceof TypeMemPtr tmp) )
+ // Must be an `int`, since int and ptr are the only two value types
+ // being tested. No representation for a generic not-null int, so no upcast.
+ return null;
+ if( tmp.isa(TypeMemPtr.VOIDPTR) )
+ return null; // Already not-null, no reason to upcast
+ // Upcast the ptr to not-null ptr, and replace in scope
+ return replace(pred,new CastNode(TypeMemPtr.VOIDPTR,ctrl,pred).peephole());
+ }
+
+ if( pred instanceof NotNode not ) {
+ // Direct use of a !value as predicate. This is a zero/null test.
+ if( Utils.find(_inputs, not.in(1)) != -1 ) {
+ Type tinit = not.in(1)._type.makeInit();
+ if( not.in(1)._type.isa(tinit) ) return null; // Already zero/null, no reason to upcast
+ return replace(not.in(1), new ConstantNode(tinit).peephole());
+ }
+ }
+ // Apr/9/2024: Attempted to replace X with Y if guarded by a test of
+ // X==Y. This didn't seem to help very much, or at least in the test
+ // cases seen so far was a very minor help.
+
+ // No upcast
+ return null;
+ }
+
+ private Node replace( Node old, Node cast ) {
+ assert old!=null && old!=cast;
+ for( int i=0; i<nIns(); i++ )
+ if( in(i)==old )
+ setDef(i,cast);
+ return cast;
+ }
+
}
diff --git a/src/main/java/com/seaofnodes/simple/node/StartNode.java b/src/main/java/com/seaofnodes/simple/node/StartNode.java
index e399138b..4b7e02a8 100644
--- a/src/main/java/com/seaofnodes/simple/node/StartNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/StartNode.java
@@ -1,25 +1,58 @@
package com.seaofnodes.simple.node;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeTuple;
-
+import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.type.*;
+import java.util.Arrays;
import java.util.BitSet;
+import java.util.HashMap;
/**
- * The Start node represents the start of the function. For now, we do not
- * have any inputs to Start because our function does not yet accept
- * parameters. When we add parameters the value of Start will be a tuple, and
- * will require Projections to extract the values. We discuss this in detail
- * in Chapter 9: Functions and Calls.
+ * The Start node represents the start of the function.
+ *
+ * Start initially has 1 input (arg) from outside and the initial control.
+ * In ch10 we also add mem aliases as structs get defined; each field in struct
+ * adds a distinct alias to Start's tuple.
*/
public class StartNode extends MultiNode {
- final TypeTuple _args;
+ // This field is NOT final, because the tuple expands as we add memory aliases
+ TypeTuple _args;
+
+ // The alias number of the first field in the struct.
+ //
+ public final HashMap<String,Integer> _aliasStarts;
+
public StartNode(Type[] args) {
super();
_args = TypeTuple.make(args);
_type = _args;
+ _aliasStarts = new HashMap<>();
+ }
+
+ /**
+ * Creates a projection for each of the struct's fields, using the field alias
+ * as the key.
+ */
+ public void addMemProj( TypeStruct ts, ScopeNode scope) {
+ int len = _args._types.length;
+ _aliasStarts.put(ts._name,len);
+
+ // resize the tuple's type array to include all fields of the struct
+ int max = len + ts._fields.length;
+ Type[] args = Arrays.copyOf(_args._types, max);
+
+ // The new members of the tuple get a mem type with an alias
+ for( int alias = len; alias < max; alias++ )
+ args[alias] = TypeMem.make(alias);
+ _type = _args = TypeTuple.make(args);
+ // For each of the fields we now add a mem projection. Note that the
+ // alias matches the slot of the field in the tuple
+ for( int alias = len; alias < max; alias++ ) {
+ String name = Parser.memName(alias);
+ Node n = new ProjNode(this, alias, name).peephole();
+ scope.define(name, args[alias], n);
+ }
}
@Override
@@ -40,7 +73,6 @@ public class StartNode extends MultiNode {
public Node idealize() { return null; }
// No immediate dominator, and idepth==0
- @Override
- Node idom() { return null; }
-
+ @Override int idepth() { return 0; }
+ @Override Node idom() { return null; }
}
diff --git a/src/main/java/com/seaofnodes/simple/node/StopNode.java b/src/main/java/com/seaofnodes/simple/node/StopNode.java
index 602feffc..3b5a7ce3 100644
--- a/src/main/java/com/seaofnodes/simple/node/StopNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/StopNode.java
@@ -51,10 +51,17 @@ public class StopNode extends Node {
return null;
}
+ @Override public Node idom() { return null; }
+
public Node addReturn(Node node) {
return addDef(node);
}
- public StopNode iterate( ) { return IterPeeps.iterate(this,false); }
- public StopNode iterate(boolean show) { return IterPeeps.iterate(this,show ); }
+ public StopNode iterate( ) { return IterPeeps.iterate(this,false).typeCheck(); }
+ public StopNode iterate(boolean show) { return IterPeeps.iterate(this,show ).typeCheck(); }
+ StopNode typeCheck() {
+ String err = walk( Node::err );
+ if( err != null ) throw new RuntimeException(err);
+ return this;
+ }
}
diff --git a/src/main/java/com/seaofnodes/simple/node/StoreNode.java b/src/main/java/com/seaofnodes/simple/node/StoreNode.java
new file mode 100644
index 00000000..8d264601
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/StoreNode.java
@@ -0,0 +1,70 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.type.*;
+
+import java.util.BitSet;
+
+/**
+ * Store represents setting a value to a memory based object, in chapter 10
+ * this means a field inside a struct.
+ */
+public class StoreNode extends MemOpNode {
+
+ /**
+ * @param name The struct field we are assigning to
+ * @param memSlice The memory alias node - this is updated after a Store
+ * @param memPtr The ptr to the struct where we will store a value
+ * @param value Value to be stored
+ */
+ public StoreNode(String name, int alias, Node memSlice, Node memPtr, Node value) {
+ super(name, alias, memSlice, memPtr, value);
+ }
+
+ @Override
+ public String label() { return "Store"; }
+ @Override
+ public String glabel() { return "."+_name+" ="; }
+ @Override
+ public boolean isMem() { return true; }
+ public Node val() { return in(3); }
+
+ @Override
+ StringBuilder _print1(StringBuilder sb, BitSet visited) {
+ return sb.append(".").append(_name).append("=").append( val()).append(";");
+ }
+
+ @Override
+ public Type compute() { return TypeMem.make(_alias); }
+
+ @Override
+ public Node idealize() {
+
+ // Simple store-after-store on same address. Should pick up the
+ // required init-store being stomped by a first user store.
+ if( mem() instanceof StoreNode st &&
+ ptr()==st.ptr() && // Must check same object
+ ptr()._type instanceof TypeMemPtr && // No bother if weird dead pointers
+ // Must have exactly one use of "this" or you get weird
+ // non-serializable memory effects in the worse case.
+ st.checkNoUseBeyond(this) ) {
+ assert Utils.eq(_name,st._name); // Equiv class aliasing is perfect
+ setDef(1,st.mem());
+ return this;
+ }
+
+ return null;
+ }
+
+ // Check that `this` has no uses beyond `that`
+ private boolean checkNoUseBeyond(Node that) {
+ if( nOuts()==1 ) return true;
+ // Add deps on the other uses (can be e.g. ScopeNode mid-parse) so that
+ // when the other uses go away we can retry.
+ for( Node use : _outputs )
+ if( use != that )
+ use.addDep(that);
+ return false;
+ }
+
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/SubNode.java b/src/main/java/com/seaofnodes/simple/node/SubNode.java
index f661be14..b87115cd 100644
--- a/src/main/java/com/seaofnodes/simple/node/SubNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/SubNode.java
@@ -35,6 +35,14 @@ public class SubNode extends Node {
@Override
public Node idealize() {
+ // x - (-y) is x+y
+ if( in(2) instanceof MinusNode minus )
+ return new AddNode(in(1),minus.in(1));
+
+ // (-x) - y is -(x+y)
+ if( in(1) instanceof MinusNode minus )
+ return new MinusNode(new AddNode(minus.in(1),in(2)).peephole());
+
return null;
}
diff --git a/src/main/java/com/seaofnodes/simple/type/Field.java b/src/main/java/com/seaofnodes/simple/type/Field.java
new file mode 100644
index 00000000..96088f90
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/type/Field.java
@@ -0,0 +1,60 @@
+package com.seaofnodes.simple.type;
+
+import com.seaofnodes.simple.Utils;
+import java.util.ArrayList;
+
+/**
+ * Represents a field in a struct. This is not a Type in the type system.
+ */
+public class Field extends Type {
+
+ // The pair {fieldName,type} uniquely identifies a field.
+
+ // Field name
+ public final String _fname;
+ // Type of the field
+ public final Type _type;
+
+ private Field(String fname, Type type ) {
+ super(TFLD);
+ _fname = fname;
+ _type = type;
+ }
+ // Make with existing alias
+ public static Field make( String fname, Type type ) {
+ return new Field(fname,type).intern();
+ }
+
+ public static final Field TEST = make("test",TypeInteger.ZERO);
+ public static void gather(ArrayList<Type> ts) { ts.add(TEST); }
+
+ @Override Field xmeet( Type that ) {
+ Field fld = (Field)that; // Invariant
+ assert _fname.equals(fld._fname);
+ return make(_fname,_type.meet(fld._type));
+ }
+
+ @Override
+ public Field dual() { return make(_fname,_type.dual()); }
+
+ @Override
+ public Field glb() {
+ return make(_fname,_type.glb());
+ }
+
+ // Override in subclasses
+ int hash() { return _fname.hashCode() ^ _type.hashCode(); }
+
+ boolean eq(Type t) {
+ Field f = (Field)t;
+ return Utils.eq(_fname,f._fname) && _type==f._type;
+ }
+
+
+ @Override
+ public StringBuilder print( StringBuilder sb ) {
+ return _type.print(sb.append(_fname).append(":"));
+ }
+
+ @Override public String str() { return _fname; }
+}
diff --git a/src/main/java/com/seaofnodes/simple/type/Type.java b/src/main/java/com/seaofnodes/simple/type/Type.java
index daaa8af6..93e27c76 100644
--- a/src/main/java/com/seaofnodes/simple/type/Type.java
+++ b/src/main/java/com/seaofnodes/simple/type/Type.java
@@ -2,6 +2,7 @@ package com.seaofnodes.simple.type;
import com.seaofnodes.simple.Utils;
+import java.util.ArrayList;
import java.util.HashMap;
/**
@@ -33,6 +34,10 @@ public class Type {
static final byte TSIMPLE = 4; // End of the Simple Types
static final byte TINT = 5; // All Integers; see TypeInteger
static final byte TTUPLE = 6; // Tuples; finite collections of unrelated Types, kept in parallel
+ static final byte TMEM = 7; // All memory (alias 0) or A slice of memory - with specific alias
+ static final byte TMEMPTR = 8; // Memory pointer type
+ static final byte TSTRUCT = 9; // Structs; tuples with named fields
+ static final byte TFLD =10; // Fields into struct
public final byte _type;
@@ -44,6 +49,21 @@ public class Type {
public static final Type TOP = new Type( TTOP ).intern(); // ANY
public static final Type CONTROL = new Type( TCTRL ).intern(); // Ctrl
public static final Type XCONTROL = new Type( TXCTRL ).intern(); // ~Ctrl
+ public static Type[] gather() {
+ ArrayList<Type> ts = new ArrayList<>();
+ ts.add(BOTTOM);
+ ts.add(CONTROL);
+ Field.gather(ts);
+ TypeInteger.gather(ts);
+ TypeMem.gather(ts);
+ TypeMemPtr.gather(ts);
+ TypeStruct.gather(ts);
+ TypeTuple.gather(ts);
+ int sz = ts.size();
+ for( int i = 0; i < sz; i++ )
+ ts.add(ts.get(i).dual());
+ return ts.toArray(new Type[ts.size()]);
+ }
// Is high or on the lattice centerline.
public boolean isHighOrConst() { return _type==TTOP || _type==TXCTRL; }
@@ -52,12 +72,26 @@ public class Type {
// Excludes both high and low values
public boolean isConstant() { return false; }
- public StringBuilder print(StringBuilder sb) {return is_simple() ? sb.append(STRS[_type]) : sb;}
+ /**
+ * Display Type name in a format that's good for IR printer
+ */
+ public StringBuilder typeName( StringBuilder sb) { return print(sb); }
+
+ public Type makeInit() { return null; }
// ----------------------------------------------------------
+ // Notes on Type interning.
+ // At the moment it is not easy to reset the interned types
+ // because we hold static references to several types and these are scattered
+ // around. This means the INTERN cache will retain all types from
+ // every run of the Parser. For this to work correctly types must be
+ // rigorous about defining when they are the same. Also types need to be
+ // immutable once defined.
+ // The rationale for interning is performance.
+
// Factory method which interns "this"
- protected <T extends Type> T intern() {
+ public <T extends Type> T intern() {
T nnn = (T)INTERN.get(this);
if( nnn==null )
INTERN.put(nnn=(T)this,this);
@@ -95,13 +129,13 @@ public class Type {
// Reverse; xmeet 2nd arg is never "is_simple" and never equal to "this".
if( is_simple() ) return this.xmeet(t );
if( t.is_simple() ) return t .xmeet(this);
- return xmeet(t); // Mixing 2 unrelated types
+ return Type.BOTTOM; // Mixing 2 unrelated types
}
// Compute meet right now. Overridden in subclasses.
// Handle cases where 'this.is_simple()' and unequal to 't'.
// Subclassed xmeet calls can assert that '!t.is_simple()'.
- protected Type xmeet(Type t) {
+ Type xmeet(Type t) {
assert is_simple(); // Should be overridden in subclass
// ANY meet anything is thing; thing meet ALL is ALL
if( _type==TBOT || t._type==TTOP ) return this;
@@ -112,17 +146,6 @@ public class Type {
return _type==TCTRL || t._type==TCTRL ? CONTROL : XCONTROL;
}
- // True if this "isa" t; e.g. 17 isa TypeInteger.BOT
- public boolean isa( Type t ) { return meet(t)==t; }
-
- // ----------------------------------------------------------
- // Our lattice is defined with a MEET and a DUAL.
- // JOIN is dual of meet of both duals.
- public final Type join(Type t) {
- if( this==t ) return this;
- return dual().meet(t.dual()).dual();
- }
-
public Type dual() {
return switch( _type ) {
case TBOT -> TOP;
@@ -134,8 +157,31 @@ public class Type {
}
// ----------------------------------------------------------
+ // Our lattice is defined with a MEET and a DUAL.
+ // JOIN is dual of meet of both duals.
+ public final Type join(Type t) {
+ if( this==t ) return this;
+ return dual().meet(t.dual()).dual();
+ }
+
+ // True if this "isa" t; e.g. 17 isa TypeInteger.BOT
+ public boolean isa( Type t ) { return meet(t)==t; }
+
+ /**
+ * Compute greatest lower bound in the lattice
+ */
+ public Type glb() { return _type==TCTRL ? XCONTROL : BOTTOM; }
+
+ // ----------------------------------------------------------
+ // Useful in the debugger, which calls toString everywhere.
+ // This is a more verbose dev-friendly print.
@Override
public final String toString() {
return print(new StringBuilder()).toString();
}
+
+ public StringBuilder print(StringBuilder sb) { return is_simple() ? sb.append(STRS[_type]) : sb;}
+
+ // This is used by error messages, and is a shorted print.
+ public String str() { return STRS[_type]; }
}
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeInteger.java b/src/main/java/com/seaofnodes/simple/type/TypeInteger.java
index ab9dbcff..8c77672b 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeInteger.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeInteger.java
@@ -1,5 +1,7 @@
package com.seaofnodes.simple.type;
+import java.util.ArrayList;
+
/**
* Integer Type
*/
@@ -28,6 +30,10 @@ public class TypeInteger extends Type {
public static TypeInteger constant(long con) { return make(true, con); }
+ public static void gather(ArrayList<Type> ts) { ts.add(ZERO); ts.add(BOT); }
+
+ // FIXME this display format is problematic
+ // In visualizer '#' gets prepended if its a constant
@Override
public StringBuilder print(StringBuilder sb) {
if( this==TOP ) return sb.append("IntTop");
@@ -35,6 +41,22 @@ public class TypeInteger extends Type {
return sb.append(_con);
}
+ @Override public String str() {
+ if( this==TOP ) return "~int";
+ if( this==BOT ) return "int";
+ return ""+_con;
+ }
+
+ /**
+ * Display Type name in a format that's good for IR printer
+ */
+ @Override
+ public StringBuilder typeName(StringBuilder sb) {
+ if( this==TOP ) return sb.append("IntTop");
+ if( this==BOT ) return sb.append("IntBot");
+ return sb.append("Int");
+ }
+
@Override
public boolean isHighOrConst() { return _is_con || _con==0; }
@@ -65,6 +87,11 @@ public class TypeInteger extends Type {
}
@Override
+ public Type glb() { return BOT; }
+
+ @Override public TypeInteger makeInit() { return ZERO; }
+
+ @Override
int hash() { return (int)(_con ^ (_is_con ? 0 : 0x4000)); }
@Override
public boolean eq( Type t ) {
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeMem.java b/src/main/java/com/seaofnodes/simple/type/TypeMem.java
new file mode 100644
index 00000000..f4caf56f
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/type/TypeMem.java
@@ -0,0 +1,64 @@
+package com.seaofnodes.simple.type;
+
+import com.seaofnodes.simple.Utils;
+import java.lang.Long;
+import java.util.BitSet;
+import java.util.ArrayList;
+
+
+/**
+ * Represents a slice of memory corresponding to a set of aliases
+ */
+public class TypeMem extends Type {
+
+ // Which slice of memory?
+ // 0 means TOP, no slice.
+ // -1 means BOT, all memory.
+ // N means slice#N.
+ private final int _alias;
+
+ private TypeMem(int alias) { super(TMEM); _alias = alias; }
+
+ public static TypeMem make(int alias) { return new TypeMem(alias).intern(); }
+ public static final TypeMem TOP = make( 0);
+ public static final TypeMem BOT = make(-1);
+
+
+ public static void gather(ArrayList<Type> ts) { ts.add(make(1)); ts.add(BOT); }
+
+ @Override
+ TypeMem xmeet(Type t) {
+ TypeMem that = (TypeMem) t; // Invariant: TypeMem and unequal
+ return _alias==0 ? that : (that._alias==0 ? this : BOT);
+ }
+
+ @Override
+ public Type dual() {
+ if( _alias== 0 ) return BOT;
+ if( _alias==-1 ) return TOP;
+ return this;
+ }
+
+ @Override
+ public Type glb() { return TypeMem.BOT; }
+
+ @Override
+ int hash() { return 9876543 + _alias; }
+
+ @Override
+ boolean eq(Type t) {
+ TypeMem that = (TypeMem) t; // Invariant
+ return _alias == that._alias;
+ }
+
+ @Override
+ public StringBuilder print(StringBuilder sb) {
+ return sb.append("MEM#").append( switch(_alias) {
+ case 0 -> "TOP";
+ case -1 -> "BOT";
+ default -> ""+_alias;
+ });
+ }
+
+ @Override public String str() { return print(new StringBuilder()).toString(); }
+}
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeMemPtr.java b/src/main/java/com/seaofnodes/simple/type/TypeMemPtr.java
new file mode 100644
index 00000000..ffedbabc
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/type/TypeMemPtr.java
@@ -0,0 +1,78 @@
+package com.seaofnodes.simple.type;
+
+import java.util.ArrayList;
+
+/**
+ * Represents a Pointer to memory.
+ *
+ * Null is generic pointer to non-existent memory.
+ * *void is a non-Null pointer to all possible structs.
+ * Pointers can be to specific struct types, or a union with Null.
+ * The distinguished *$BOT ptr represents union of *void and Null.
+ * The distinguished *$TOP ptr represents the dual of *$BOT.
+ */
+public class TypeMemPtr extends Type {
+ // A TypeMemPtr is pair (obj,nil)
+ // where obj is one of
+ // (null,TypeStruct).
+ // where nil is one of
+ // (true,false) meaning an explicit null is allowed or not
+
+ public final TypeStruct _obj; // null, a TypeStruct, or sentinel TypeStruct.MANY
+ public final boolean _nil;
+
+ private TypeMemPtr(TypeStruct obj, boolean nil) {
+ super(TMEMPTR);
+ _obj = obj;
+ _nil = nil;
+ }
+ public static TypeMemPtr make(TypeStruct obj, boolean nil) { return new TypeMemPtr(obj, nil).intern(); }
+ public static TypeMemPtr make(TypeStruct obj) { return TypeMemPtr.make(obj, false); }
+
+ public static final TypeMemPtr BOT = make(TypeStruct.BOT,true);
+ public static final TypeMemPtr TOP = BOT.dual();
+ public static final TypeMemPtr NULLPTR = make(TypeStruct.TOP,true);
+ public static final TypeMemPtr VOIDPTR = NULLPTR.dual(); // A bottom mix of not-null ptrs, like C's void* but not null
+ public static final TypeMemPtr TEST= make(TypeStruct.TEST,false);
+ public static void gather(ArrayList<Type> ts) { ts.add(NULLPTR); ts.add(BOT); ts.add(TEST); }
+
+ @Override
+ Type xmeet(Type t) {
+ TypeMemPtr that = (TypeMemPtr) t;
+ return TypeMemPtr.make((TypeStruct)_obj.meet(that._obj), _nil | that._nil);
+ }
+
+ @Override
+ public TypeMemPtr dual() { return TypeMemPtr.make(_obj==null ? null : _obj.dual(), !_nil); }
+
+ @Override
+ public Type glb() {
+ if( _obj==null ) return BOT;
+ return make(_obj.glb(),true);
+ }
+ @Override public TypeMemPtr makeInit() { return NULLPTR; }
+
+ @Override
+ int hash() { return (_obj==null ? 0xDEADBEEF : _obj.hashCode()) ^ (_nil ? 1024 : 0); }
+
+ @Override
+ boolean eq(Type t) {
+ TypeMemPtr ptr = (TypeMemPtr)t; // Invariant
+ return _obj == ptr._obj && _nil == ptr._nil;
+ }
+
+ // [void,name,MANY]*[,?]
+ @Override
+ public StringBuilder print(StringBuilder sb) {
+ if( this== NULLPTR) return sb.append("null");
+ if( this== VOIDPTR) return sb.append("*void");
+ return _obj.print(sb.append("*")).append(_nil ? "?" : "");
+ }
+
+ @Override public String str() {
+ if( this== NULLPTR) return "null";
+ if( this== VOIDPTR) return "*void";
+ return "*"+_obj.str()+(_nil ? "?" : "");
+ }
+
+}
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeStruct.java b/src/main/java/com/seaofnodes/simple/type/TypeStruct.java
new file mode 100644
index 00000000..6c837919
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/type/TypeStruct.java
@@ -0,0 +1,121 @@
+package com.seaofnodes.simple.type;
+
+import com.seaofnodes.simple.Utils;
+import java.util.ArrayList;
+
+/**
+ * Represents a struct type.
+ */
+public class TypeStruct extends Type {
+
+ // For now in terms of the lattice
+ // a struct type just stays as is
+
+ public final String _name;
+ public final Field[] _fields;
+
+ private TypeStruct(String name, Field[] fields) {
+ super(Type.TSTRUCT);
+ _name = name;
+ _fields = fields;
+ }
+
+ public static TypeStruct make(String name, Field[] fields) { return new TypeStruct(name, fields).intern(); }
+ public static TypeStruct make(String name, ArrayList<Field> fields) { return make(name,fields.toArray(new Field[fields.size()])); }
+
+ public static final TypeStruct TOP = make("$TOP",new Field [0]);
+ public static final TypeStruct BOT = make("$BOT",new Field [0]);
+ public static final TypeStruct TEST = make("test",new Field[]{Field.TEST});
+ public static void gather(ArrayList<Type> ts) { ts.add(TEST); ts.add(BOT); }
+
+ public int find(String fname) {
+ for( int i=0; i<_fields.length; i++ )
+ if( _fields[i]._fname.equals(fname) )
+ return i;
+ return -1;
+ }
+
+ @Override
+ Type xmeet(Type t) {
+ TypeStruct that = (TypeStruct) t;
+ if( this==TOP ) return that;
+ if( that==TOP ) return this;
+ if( this==BOT ) return BOT;
+ if( that==BOT ) return BOT;
+
+ // Within the same compilation unit, struct names are unique. If the
+ // names differ, its different structs. Across many compilation units,
+ // structs with the same name but different field layouts can be
+ // interned... which begs the question:
+ // "What is the meet of structs from two different compilation units?"
+ // And the answer is: "don't ask".
+ if( !_name.equals(that._name) )
+ return BOT; // It's a struct; that's about all we know
+ // Now all fields should be the same, so just do field meets
+ assert _fields.length == that._fields.length;
+ Field[] flds = new Field[_fields.length];
+ for( int i=0; i<_fields.length; i++ )
+ flds[i] = (Field)_fields[i].meet(that._fields[i]);
+ return make(_name,flds);
+ }
+
+ @Override
+ public TypeStruct dual() {
+ if( this==TOP ) return BOT;
+ if( this==BOT ) return TOP;
+ Field[] flds = new Field[_fields.length];
+ for( int i=0; i<_fields.length; i++ )
+ flds[i] = _fields[i].dual();
+ return make(_name,flds);
+ }
+
+ // Keeps the same struct, but lower-bounds all fields.
+ @Override
+ public TypeStruct glb() {
+ if( _glb() ) return this;
+ // Need to glb each field
+ Field[] flds = new Field[_fields.length];
+ for( int i=0; i<_fields.length; i++ )
+ flds[i] = _fields[i].glb();
+ return make(_name,flds);
+ }
+ private boolean _glb() {
+ for( Field f : _fields )
+ if( f.glb() != f )
+ return false;
+ return true;
+ }
+
+ @Override
+ boolean eq(Type t) {
+ TypeStruct ts = (TypeStruct)t; // Invariant
+ if( !_name.equals(ts._name) )
+ return false;
+ if( _fields.length!=ts._fields.length )
+ return false;
+ for( int i = 0; i < _fields.length; i++ )
+ if( _fields[i] != ts._fields[i] )
+ return false;
+ return true;
+ }
+
+ @Override
+ int hash() {
+ long hash = _name.hashCode();
+ for( Field f : _fields ) hash = Utils.rot(hash,13) ^ f.hashCode();
+ return Utils.fold(hash);
+ }
+
+ @Override
+ public StringBuilder print(StringBuilder sb) {
+ sb.append(_name).append(" {\n");
+ for( Field f : _fields ) {
+ sb.append(" ").append(f._fname).append(":");
+ f._type.print(sb);
+ sb.append(";\n");
+ }
+ return sb.append("}");
+ }
+
+ @Override public String str() { return _name; }
+}
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeTuple.java b/src/main/java/com/seaofnodes/simple/type/TypeTuple.java
index a2a6a095..0aa019a7 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeTuple.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeTuple.java
@@ -1,5 +1,7 @@
package com.seaofnodes.simple.type;
+import java.util.ArrayList;
+
public class TypeTuple extends Type {
public final Type[] _types;
@@ -7,8 +9,11 @@ public class TypeTuple extends Type {
private TypeTuple(Type[] types) { super(TTUPLE); _types = types; }
public static TypeTuple make(Type... types) { return new TypeTuple(types).intern(); }
+ private static TypeTuple TEST = make(TypeInteger.BOT,TypeMemPtr.TEST);
+ public static void gather(ArrayList<Type> ts) { ts.add(TEST); }
+
@Override
- public Type xmeet(Type other) {
+ Type xmeet(Type other) {
TypeTuple tt = (TypeTuple)other; // contract from xmeet
assert _types.length == tt._types.length;
Type[] ts = new Type[_types.length];
@@ -25,6 +30,14 @@ public class TypeTuple extends Type {
}
@Override
+ public Type glb() {
+ Type[] ts = new Type[_types.length];
+ for( int i=0; i<_types.length; i++ )
+ ts[i] = _types[i].glb();
+ return make(ts);
+ }
+
+ @Override
public StringBuilder print(StringBuilder sb) {
sb.append("[");
for( Type t : _types )
@@ -34,6 +47,21 @@ public class TypeTuple extends Type {
return sb;
}
+ @Override public String str() { return print(new StringBuilder()).toString(); }
+
+ /**
+ * Display Type name in a format that's good for IR printer
+ */
+ @Override
+ public StringBuilder typeName(StringBuilder sb) {
+ sb.append("[");
+ for( Type t : _types )
+ t.typeName(sb).append(",");
+ sb.setLength(sb.length()-1);
+ sb.append("]");
+ return sb;
+ }
+
public static final TypeTuple IF_BOTH = make(new Type[]{Type. CONTROL,Type. CONTROL});
public static final TypeTuple IF_NEITHER = make(new Type[]{Type.XCONTROL,Type.XCONTROL});
public static final TypeTuple IF_TRUE = make(new Type[]{Type. CONTROL,Type.XCONTROL});
diff --git a/src/test/java/com/seaofnodes/simple/Chapter01Test.java b/src/test/java/com/seaofnodes/simple/Chapter01Test.java
index 13b42f96..89882b2f 100644
--- a/src/test/java/com/seaofnodes/simple/Chapter01Test.java
+++ b/src/test/java/com/seaofnodes/simple/Chapter01Test.java
@@ -41,7 +41,7 @@ public class Chapter01Test {
new Parser("ret").parse();
fail();
} catch( RuntimeException e ) {
- assertEquals("Syntax error, expected =: ",e.getMessage());
+ assertEquals("Undefined name 'ret'",e.getMessage());
}
}
@@ -83,7 +83,7 @@ public class Chapter01Test {
new Parser("return100").parse();
fail();
} catch( RuntimeException e ) {
- assertEquals("Syntax error, expected =: ",e.getMessage());
+ assertEquals("Undefined name 'return100'",e.getMessage());
}
}
diff --git a/src/test/java/com/seaofnodes/simple/Chapter03Test.java b/src/test/java/com/seaofnodes/simple/Chapter03Test.java
index 2246b927..64ff153e 100644
--- a/src/test/java/com/seaofnodes/simple/Chapter03Test.java
+++ b/src/test/java/com/seaofnodes/simple/Chapter03Test.java
@@ -40,7 +40,7 @@ public class Chapter03Test {
@Test
public void testVarDist() {
- Parser parser = new Parser("int x0=1; int y0=2; int x1=3; int y1=4; return (x0-x1)*(x0-x1) + (y0-y1)*(y0-y1);");
+ Parser parser = new Parser("int x0=1; int y0=2; int x1=3; int y1=4; return (x0-x1)*(x0-x1) + (y0-y1)*(y0-y1); ");
StopNode ret = parser.parse();
assertEquals("return 8;", ret.print());
}
diff --git a/src/test/java/com/seaofnodes/simple/Chapter05Test.java b/src/test/java/com/seaofnodes/simple/Chapter05Test.java
index 6ad3af15..35e54fa9 100644
--- a/src/test/java/com/seaofnodes/simple/Chapter05Test.java
+++ b/src/test/java/com/seaofnodes/simple/Chapter05Test.java
@@ -22,7 +22,7 @@ else {
return a;""");
StopNode ret = parser.parse().iterate();
- assertEquals("return Phi(Region17,(arg+2),(arg-3));", ret.toString());
+ assertEquals("return Phi(Region18,(arg+2),(arg-3));", ret.toString());
}
@Test
@@ -65,7 +65,7 @@ else
b=a+1;
return a+b;""");
StopNode ret = parser.parse().iterate();
- assertEquals("return ((arg*2)+Phi(Region20,2,3));", ret.toString());
+ assertEquals("return ((arg*2)+Phi(Region21,2,3));", ret.toString());
}
@Test
@@ -80,7 +80,7 @@ else
a=b+1;
return a+b;""");
StopNode ret = parser.parse().iterate();
- assertEquals("return ((Phi(Region31,(arg*2),arg)+arg)+Phi(Region,4,5));", ret.toString());
+ assertEquals("return ((Phi(Region32,(arg*2),arg)+arg)+Phi(Region,4,5));", ret.toString());
}
@Test
@@ -100,7 +100,7 @@ else
return a;
""", TypeInteger.BOT);
StopNode stop = parser.parse().iterate();
- assertEquals("return Phi(Region33,Phi(Region21,2,3),Phi(Region31,4,5));", stop.toString());
+ assertEquals("return Phi(Region36,Phi(Region22,2,3),Phi(Region34,4,5));", stop.toString());
}
@Test
@@ -116,7 +116,7 @@ if( arg==0 )
return arg+a+b;
""", TypeInteger.BOT);
StopNode stop = parser.parse();
- assertEquals("return ((arg+Phi(Region13,1,0))+Phi(Region22,2,0));", stop.toString());
+ assertEquals("return ((arg+Phi(Region13,1,0))+Phi(Region28,2,0));", stop.toString());
}
@Test
@@ -206,7 +206,7 @@ return a;""");
new Parser("int a=1; ififif(arg)inta=2;return a;").parse();
fail();
} catch( RuntimeException e ) {
- assertEquals("Syntax error, expected =: (",e.getMessage());
+ assertEquals("Undefined name 'ififif'",e.getMessage());
}
}
diff --git a/src/test/java/com/seaofnodes/simple/Chapter06Test.java b/src/test/java/com/seaofnodes/simple/Chapter06Test.java
index 054e96e8..097c2617 100644
--- a/src/test/java/com/seaofnodes/simple/Chapter06Test.java
+++ b/src/test/java/com/seaofnodes/simple/Chapter06Test.java
@@ -65,7 +65,7 @@ else
b=5;
return b;""", TypeInteger.BOT);
StopNode stop = parser.parse().iterate();
- assertEquals("return Phi(Region32,42,5);", stop.toString());
+ assertEquals("return Phi(Region37,42,5);", stop.toString());
}
@Test
@@ -84,7 +84,7 @@ else
b=5;
return b;""", TypeInteger.BOT);
StopNode stop = parser.parse().iterate();
- assertEquals("return Phi(Region29,2,5);", stop.toString());
+ assertEquals("return Phi(Region30,2,5);", stop.toString());
}
@Test
@@ -144,7 +144,7 @@ else
return a;
""", TypeInteger.BOT);
StopNode stop = parser.parse().iterate();
- assertEquals("return Phi(Region37,3,Phi(Region35,4,5));", stop.toString());
+ assertEquals("return Phi(Region41,3,Phi(Region39,4,5));", stop.toString());
}
@Test
@@ -251,7 +251,7 @@ if( arg ) {
return a+b+c;
""");
StopNode ret = parser.parse().iterate();
- assertEquals("return (Phi(Region35,Phi(Region22,2,3),0)+Phi(Region,3,1));", ret.toString());
+ assertEquals("return (Phi(Region36,Phi(Region23,2,3),0)+Phi(Region,3,1));", ret.toString());
}
diff --git a/src/test/java/com/seaofnodes/simple/Chapter07Test.java b/src/test/java/com/seaofnodes/simple/Chapter07Test.java
index adf10471..de9d16f2 100644
--- a/src/test/java/com/seaofnodes/simple/Chapter07Test.java
+++ b/src/test/java/com/seaofnodes/simple/Chapter07Test.java
@@ -37,7 +37,7 @@ if(arg){}else{
return a;
""");
StopNode stop = parser.parse().iterate();
- assertEquals("return Phi(Region22,1,Phi(Loop11,1,(Phi_a+1)));", stop.toString());
+ assertEquals("return Phi(Region24,1,Phi(Loop13,1,(Phi_a+1)));", stop.toString());
}
@Test
@@ -74,7 +74,7 @@ return b;
""");
Node._disablePeephole = true;
StopNode stop = parser.parse();
- assertEquals("return Phi(Loop8,2,Phi(Region26,Phi_b,4));", stop.toString());
+ assertEquals("return Phi(Loop8,2,Phi(Region27,Phi_b,4));", stop.toString());
assertTrue(stop.ret().ctrl() instanceof ProjNode);
Node._disablePeephole = false;
}
@@ -94,7 +94,7 @@ while(a < 10) {
return b;
""");
StopNode stop = parser.parse().iterate();
- assertEquals("return Phi(Loop8,2,(Phi(Region26,Phi_b,4)+1));", stop.toString());
+ assertEquals("return Phi(Loop8,2,(Phi(Region27,Phi_b,4)+1));", stop.toString());
assertTrue(stop.ret().ctrl() instanceof ProjNode);
}
diff --git a/src/test/java/com/seaofnodes/simple/Chapter08Test.java b/src/test/java/com/seaofnodes/simple/Chapter08Test.java
index cea6dd0f..6688d598 100644
--- a/src/test/java/com/seaofnodes/simple/Chapter08Test.java
+++ b/src/test/java/com/seaofnodes/simple/Chapter08Test.java
@@ -1,5 +1,6 @@
package com.seaofnodes.simple;
+import com.seaofnodes.simple.evaluator.Evaluator;
import com.seaofnodes.simple.node.*;
import com.seaofnodes.simple.type.TypeInteger;
import org.junit.Assert;
@@ -25,8 +26,8 @@ return arg;
StopNode stop = parser.parse().iterate();
assertEquals("return Phi(Region36,Phi(Region25,Phi(Loop6,arg,(Phi_arg+1)),Add),Add);", stop.toString());
assertTrue(stop.ret().ctrl() instanceof RegionNode);
- Assert.assertEquals(5, GraphEvaluator.evaluate(stop, 1));
- Assert.assertEquals(10, GraphEvaluator.evaluate(stop, 6));
+ Assert.assertEquals(5L, Evaluator.evaluate(stop, 1));
+ Assert.assertEquals(10L, Evaluator.evaluate(stop, 6));
}
diff --git a/src/test/java/com/seaofnodes/simple/Chapter09Test.java b/src/test/java/com/seaofnodes/simple/Chapter09Test.java
index 8103b903..048a58c7 100644
--- a/src/test/java/com/seaofnodes/simple/Chapter09Test.java
+++ b/src/test/java/com/seaofnodes/simple/Chapter09Test.java
@@ -1,5 +1,6 @@
package com.seaofnodes.simple;
+import com.seaofnodes.simple.evaluator.Evaluator;
import com.seaofnodes.simple.node.*;
import com.seaofnodes.simple.type.Type;
import com.seaofnodes.simple.type.TypeInteger;
@@ -43,8 +44,8 @@ return x;
""");
StopNode stop = parser.parse();
assertEquals("Stop[ return (arg*2); return (Mul+1); ]", stop.toString());
- Assert.assertEquals(2, GraphEvaluator.evaluate(stop, 1));
- Assert.assertEquals(23, GraphEvaluator.evaluate(stop, 11));
+ Assert.assertEquals(2L, Evaluator.evaluate(stop, 1));
+ Assert.assertEquals(23L, Evaluator.evaluate(stop, 11));
}
@Test
@@ -55,7 +56,7 @@ return arg*arg-arg*arg;
""");
StopNode stop = parser.parse();
assertEquals("return 0;", stop.toString());
- Assert.assertEquals(0, GraphEvaluator.evaluate(stop, 1));
+ Assert.assertEquals(0L, Evaluator.evaluate(stop, 1));
}
@Test
@@ -70,7 +71,7 @@ return arg;
""");
StopNode stop = parser.parse().iterate();
assertEquals("return Phi(Loop7,arg,(Phi_arg+2));", stop.toString());
- Assert.assertEquals(11, GraphEvaluator.evaluate(stop, 1));
+ Assert.assertEquals(11L, Evaluator.evaluate(stop, 1));
}
@Test
@@ -87,7 +88,7 @@ return arg;
""");
StopNode stop = parser.parse().iterate();
assertEquals("return Phi(Loop8,arg,(Phi_arg+4));", stop.toString());
- Assert.assertEquals(13, GraphEvaluator.evaluate(stop, 1));
+ Assert.assertEquals(13L, Evaluator.evaluate(stop, 1));
}
@Test
@@ -137,26 +138,6 @@ while(v1+arg) {
}
@Test
- public void testSccp() {
- Parser parser = new Parser(
-"""
-int x = 1;
-int cnt = 5;
-while (cnt) {
- cnt = cnt - 1;
- if (x == 0) {
- x = x + 1;
- }
-}
-return x;
-"""
- );
- StopNode stop = parser.parse().iterate();
- assertEquals("return Phi(Loop8,1,Phi(Region26,(Phi_x+1),Phi_x));", stop.toString());
-
- }
-
- @Test
public void testWhile0() {
Parser parser = new Parser("while(0) continue; if(0) arg=0;");
StopNode stop = parser.parse().iterate();
diff --git a/src/test/java/com/seaofnodes/simple/Chapter10Test.java b/src/test/java/com/seaofnodes/simple/Chapter10Test.java
new file mode 100644
index 00000000..f2e7ca2c
--- /dev/null
+++ b/src/test/java/com/seaofnodes/simple/Chapter10Test.java
@@ -0,0 +1,404 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.node.Node;
+import com.seaofnodes.simple.node.StopNode;
+import com.seaofnodes.simple.type.*;
+import org.junit.Test;
+
+import java.util.Arrays;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+public class Chapter10Test {
+
+ @Test
+ public void testFuzzer() {
+ Parser parser = new Parser(
+"""
+int a = arg/3;
+int b = arg*5;
+int x = arg*7;
+int y = arg/11;
+int p; int g; int h;
+if( (arg/13)==0 ) {
+ p = x + y;
+ g = x;
+ h = y;
+} else {
+ p = a + b;
+ g = a;
+ h = b;
+}
+int r = g+h;
+return p-r;
+""");
+ StopNode stop = parser.parse().iterate();
+ assertEquals("return 0;", stop.toString());
+ }
+
+ @Test
+ public void testStruct() {
+ Parser parser = new Parser("""
+struct Bar {
+ int a;
+ int b;
+}
+struct Foo {
+ int x;
+}
+Foo? foo = null;
+Bar bar = new Bar;
+bar.a = 1;
+bar.a = 2;
+return bar.a;
+""");
+ StopNode stop = parser.parse().iterate();
+ assertEquals("return 2;", stop.toString());
+ }
+
+ @Test
+ public void testExample() {
+ Parser parser = new Parser("""
+struct Vector2D { int x; int y; }
+Vector2D v = new Vector2D;
+v.x = 1;
+if (arg)
+ v.y = 2;
+else
+ v.y = 3;
+return v;
+""");
+ StopNode stop = parser.parse().iterate();
+ assertEquals("return new Vector2D;", stop.toString());
+ }
+
+ @Test
+ public void testBug() {
+ Parser parser = new Parser("""
+struct s0 {
+ int v0;
+}
+s0? v1=null;
+int v3=v1.zAicm;
+""");
+ try { parser.parse(); fail(); }
+ catch( Exception e ) { assertEquals("Accessing unknown field 'zAicm' from 'null'",e.getMessage()); }
+ }
+
+ @Test
+ public void testBug2() {
+ Parser parser = new Parser("""
+struct s0 { int v0; }
+arg=0+new s0.0;
+""");
+ try { parser.parse(); fail(); }
+ catch( Exception e ) { assertEquals("Expected an identifier, found 'null'",e.getMessage()); }
+ }
+
+ @Test
+ public void testLoop() {
+ Parser parser = new Parser("""
+struct Bar { int a; }
+Bar bar = new Bar;
+while (arg) {
+ bar.a = bar.a + 2;
+ arg = arg + 1;
+}
+return bar.a;
+""");
+ StopNode stop = parser.parse().iterate();
+ assertEquals("return Phi(Loop10,0,(Phi_a+2));", stop.toString());
+ }
+
+ @Test
+ public void testIf() {
+ Parser parser = new Parser("""
+struct Bar { int a; }
+Bar bar = new Bar;
+if (arg) bar = null;
+bar.a = 1;
+return bar.a;
+""");
+ try { parser.parse().iterate(); fail(); }
+ catch( Exception e ) { assertEquals("Type null is not of declared type *Bar",e.getMessage()); }
+ }
+
+ @Test
+ public void testIf2() {
+ Parser parser = new Parser("""
+struct Bar { int a; }
+Bar? bar = null;
+if (arg) bar = new Bar;
+bar.a = 1;
+return bar.a;
+""");
+ try { parser.parse().iterate(); fail(); }
+ catch( Exception e ) { assertEquals("Might be null accessing 'a'",e.getMessage()); }
+ }
+
+ @Test
+ public void testIf3() {
+ Parser parser = new Parser("""
+struct Bar { int a; }
+Bar bar = null;
+if (arg) bar = null;
+bar.a = 1;
+return bar.a;
+""");
+ try { parser.parse(); fail(); }
+ catch( Exception e ) { assertEquals("Type null is not of declared type *Bar", e.getMessage()); }
+ }
+
+ @Test
+ public void testIfOrNull() {
+ Parser parser = new Parser("""
+struct Bar { int a; }
+Bar? bar = new Bar;
+if (arg) bar = null;
+if( bar ) bar.a = 1;
+return bar;
+""");
+ StopNode stop = parser.parse().iterate();
+ assertEquals("return Phi(Region15,null,new Bar);", stop.toString());
+ }
+
+ @Test
+ public void testIfOrNull2() {
+ Parser parser = new Parser(
+"""
+struct Bar { int a; }
+Bar? bar = new Bar;
+if (arg) bar = null;
+int rez = 3;
+if( !bar ) rez=4;
+else bar.a = 1;
+return rez;
+""");
+ StopNode stop = parser.parse().iterate();
+ assertEquals("return Phi(Region32,4,3);", stop.toString());
+ }
+
+ @Test
+ public void testWhileWithNullInside() {
+ Parser parser = new Parser("""
+struct s0 {int v0;}
+s0? v0 = new s0;
+int ret = 0;
+while(arg) {
+ ret = v0.v0;
+ v0 = null;
+ arg = arg - 1;
+}
+return ret;
+""");
+ try { parser.parse().iterate(); fail(); }
+ catch( Exception e ) { assertEquals("Might be null accessing 'v0'", e.getMessage()); }
+ }
+
+ @Test
+ public void testRedeclareStruct() {
+ Parser parser = new Parser("""
+struct s0 {
+ int v0;
+}
+s0? v1=new s0;
+s0? v1;
+v1=new s0;
+""");
+ try { parser.parse(); fail(); }
+ catch( Exception e ) { assertEquals("Redefining name 'v1'", e.getMessage()); }
+ }
+
+ @Test
+ public void testIter() {
+ // Build and use an iterator
+ Parser parser = new Parser(
+"""
+struct Iter {
+ int x;
+ int len;
+}
+Iter i = new Iter;
+i.len = arg;
+int sum=0;
+while( i.x < i.len ) {
+ sum = sum + i.x;
+ i.x = i.x + 1;
+}
+return sum;
+""");
+ StopNode stop = parser.parse().iterate();
+ assertEquals("return Phi(Loop14,0,(Phi(Loop,0,(Phi_x+1))+Phi_sum));", stop.toString());
+ }
+
+
+
+
+ @Test
+ public void test1() {
+ Parser parser = new Parser("""
+struct s0 {int v0;}
+s0 ret = new s0;
+while(arg) {
+ s0 v0 = new s0;
+ v0.v0 = arg;
+ arg = arg-1;
+ if (arg==5) ret=v0;
+}
+return ret;
+""");
+ StopNode stop = parser.parse().iterate();
+ assertEquals("return Phi(Loop10,new s0,Phi(Region31,new s0,Phi_ret));", stop.toString());
+ }
+
+ @Test
+ public void test2() {
+ Parser parser = new Parser("""
+struct s0 {int v0;}
+s0 ret = new s0;
+s0 v0 = new s0;
+while(arg) {
+ v0.v0 = arg;
+ arg = arg-1;
+ if (arg==5) ret=v0;
+}
+return ret;
+""");
+ StopNode stop = parser.parse().iterate();
+ assertEquals("return Phi(Loop13,new s0,Phi(Region32,new s0,Phi_ret));", stop.toString());
+ }
+
+
+ @Test
+ public void test3() {
+ Parser parser = new Parser("""
+struct s0 {int v0;}
+s0 ret = new s0;
+while(arg < 10) {
+ s0 v0 = new s0;
+ if (arg == 5) ret=v0;
+ arg = arg + 1;
+}
+return ret;
+""");
+ StopNode stop = parser.parse().iterate();
+ assertEquals("return Phi(Loop10,new s0,Phi(Region30,new s0,Phi_ret));", stop.toString());
+ }
+
+ @Test
+ public void testBug3() {
+ Parser parser = new Parser("""
+struct s0 {
+ int f0;
+}
+if(0>=0) return new s0;
+return new s0;
+int v0=null.f0;
+""");
+ try { parser.parse(); fail(); }
+ catch( Exception e ) { assertEquals("Accessing unknown field 'f0' from 'null'", e.getMessage()); }
+ }
+
+ @Test
+ public void testBug4() {
+ Parser parser = new Parser("""
+if(0) {
+ while(0) if(arg) continue;
+ int v0=0;
+ while(1) {
+ int arg=-arg;
+ v0=arg;
+ }
+}
+ """);
+ StopNode stop = parser.parse().iterate();
+ assertEquals("Stop[ ]", stop.toString());
+ }
+
+ @Test
+ public void testBug5() {
+ Parser parser = new Parser("""
+struct s0 {
+ int f0;
+}
+if(0) return 0;
+else return new s0;
+if(new s0.f0) return 0;
+ """);
+ StopNode stop = parser.parse().iterate();
+ assertEquals("return new s0;", stop.toString());
+ }
+
+ @Test
+ public void testBug6MissedWorklist() {
+ Parser parser = new Parser("""
+while(0) {}
+int v4=0;
+while(0<arg) {
+ v4=v4+1;
+ while(1) v4=-v4;
+ while(0) arg=-1;
+}
+return 0;
+ """);
+ StopNode stop = parser.parse().iterate();
+ }
+
+ @Test
+ public void testBug7() {
+ Parser parser = new Parser("""
+struct s0 { int f0; }
+s0 v0 = new s0;
+while(v0.f0) {}
+s0 v1 = v0;
+return v1;
+ """);
+ StopNode stop = parser.parse().iterate();
+ assertEquals("return new s0;", stop.toString());
+ }
+
+
+ @Test
+ public void testBug8() {
+ Parser parser = new Parser("""
+int v2=0;
+while(0)
+while(0) {}
+{
+ {
+ {
+ int v36=0;
+ {
+ while(0) {
+ {
+ while(-v2) {
+ {
+ while(v36) {
+ while(v2) return 0;
+ break;
+ } }
+ if(-v2) break;
+ }
+ }
+ }
+ }
+ } }
+}
+""");
+ StopNode stop = parser.parse().iterate();
+ assertEquals("Stop[ ]", stop.toString());
+ }
+
+ @Test
+ public void testBug9() {
+ Parser parser = new Parser("""
+int v0=arg==0;
+while(v0) continue;
+return 0;
+""");
+ StopNode stop = parser.parse().iterate();
+ assertEquals("return 0;", stop.toString());
+ }
+
+}
diff --git a/src/test/java/com/seaofnodes/simple/SchedulerTest.java b/src/test/java/com/seaofnodes/simple/SchedulerTest.java
new file mode 100644
index 00000000..5def2782
--- /dev/null
+++ b/src/test/java/com/seaofnodes/simple/SchedulerTest.java
@@ -0,0 +1,74 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.evaluator.Evaluator;
+import com.seaofnodes.simple.node.StopNode;
+import org.junit.Assert;
+import org.junit.Ignore;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class SchedulerTest {
+
+ private static void assertObj(Object obj, String name, Object... fields) {
+ assertEquals(Evaluator.Obj.class, obj.getClass());
+ var o = (Evaluator.Obj)obj;
+ assertEquals(name, o.struct()._name);
+ Assert.assertArrayEquals(fields, o.fields());
+ }
+
+ @Test
+ @Ignore
+ public void testJig() {
+ Parser parser = new Parser("""
+struct S {
+ int f;
+}
+S v=new S;
+v.f = 2;
+int i=v.f;
+if (arg) v.f=1;
+return i;
+""");
+ StopNode._disablePeephole = true;
+ StopNode stop = parser.parse(true);//.iterate();
+ var eval = new Evaluator(stop);
+ assertEquals(2L, eval.evaluate(1, 10));
+ }
+
+ @Test
+ public void testStoreInIf() {
+ Parser parser = new Parser("""
+struct S {
+ int f;
+}
+S v0=new S;
+if(arg) v0.f=1;
+return v0;
+""");
+ StopNode stop = parser.parse().iterate();
+ var eval = new Evaluator(stop);
+ assertObj(eval.evaluate(0, 10), "S", 0L);
+ assertObj(eval.evaluate(1, 10), "S", 1L);
+ }
+
+ @Test
+ public void testStoreInIf2() {
+ Parser parser = new Parser("""
+struct S {
+ int f;
+}
+S v=new S;
+v.f = 2;
+int i=new S.f;
+i=v.f;
+if (arg) v.f=1;
+return i;
+""");
+ StopNode stop = parser.parse().iterate();
+ var eval = new Evaluator(stop);
+ assertEquals(2L, eval.evaluate(0, 10));
+ assertEquals(2L, eval.evaluate(1, 10));
+ }
+
+}
diff --git a/src/test/java/com/seaofnodes/simple/TypeTest.java b/src/test/java/com/seaofnodes/simple/TypeTest.java
new file mode 100644
index 00000000..f9c580cc
--- /dev/null
+++ b/src/test/java/com/seaofnodes/simple/TypeTest.java
@@ -0,0 +1,145 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.type.*;
+import org.junit.Assert;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertSame;
+
+public class TypeTest {
+
+ // Test basic properties and GLB
+ @Test
+ public void testTypeAdHoc() {
+ TypeStruct s1 = TypeStruct.make("s1", new Field[]{
+ Field.make("a", TypeInteger.BOT),
+ Field.make("b", TypeInteger.BOT) });
+ TypeStruct s2 = TypeStruct.make("s2", new Field[]{
+ Field.make("a", TypeInteger.BOT),
+ Field.make("b", TypeInteger.BOT) });
+ Assert.assertEquals(s1, s1.glb());
+ Assert.assertNotEquals(s1, s1.dual());
+ Assert.assertEquals(s1, s1.dual().glb());
+
+ TypeMem m1 = TypeMem.make(1);
+ TypeMem m2 = TypeMem.make(2);
+ TypeMem m3 = TypeMem.make(3);
+ TypeMem m4 = TypeMem.make(4);
+
+ Assert.assertNotEquals(m1, m2);
+ Assert.assertNotEquals(m2, m3);
+ Assert.assertNotEquals(m3, m4);
+
+ Assert.assertEquals(TypeStruct.BOT, s1.meet(s2));
+ Assert.assertEquals(TypeMem .BOT, m1.meet(m2));
+ Assert.assertEquals(TypeMem .BOT, m2.meet(m3));
+ Assert.assertEquals(TypeMem .BOT, m3.meet(m4));
+
+ Assert.assertEquals(TypeMem.BOT, m1.glb());
+ Assert.assertEquals(m1, m1.dual());
+ Assert.assertEquals(TypeMem.TOP, m1.glb().dual());
+
+ TypeMemPtr ptr1 = TypeMemPtr.make(s1);
+ Assert.assertEquals(s1, ptr1._obj);
+ TypeMemPtr ptr2 = TypeMemPtr.make(s2);
+ Assert.assertEquals(s2, ptr2._obj);
+
+ TypeMemPtr ptr1nil = TypeMemPtr.make(s1, true);
+ Assert.assertEquals(s1, ptr1nil._obj);
+ Assert.assertTrue(ptr1nil._nil);
+ Assert.assertFalse(ptr1nil._obj==null);
+ TypeMemPtr ptr2nil = TypeMemPtr.make(s2, true);
+ Assert.assertEquals(s2, ptr2nil._obj);
+
+ Assert.assertNotEquals(ptr1, ptr2);
+ Assert.assertNotEquals(ptr1, ptr1.glb());
+ Assert.assertEquals(ptr1nil, ptr1.glb());
+
+ Assert.assertEquals(ptr1, ptr1.dual().dual());
+ Assert.assertEquals(ptr1.glb(), ptr1.dual().glb());
+ Assert.assertEquals(TypeMemPtr.BOT, ptr1.meet(ptr2nil));
+ Assert.assertEquals(ptr1.glb(), ptr1.meet(TypeMemPtr.NULLPTR));
+
+ TypeMemPtr TOP = TypeMemPtr.TOP;
+ TypeMemPtr BOT = TypeMemPtr.BOT;
+ TypeMemPtr PTR = TypeMemPtr.VOIDPTR;
+ TypeMemPtr NULL = TypeMemPtr.NULLPTR;
+ Type PTR_meet_NULL = NULL.meet(PTR);
+ Assert.assertEquals(BOT, PTR_meet_NULL);
+ Type ptr1_meet_ptr2 = ptr1.meet(ptr2);
+ Assert.assertEquals(PTR, ptr1_meet_ptr2);
+ Type NULL_join_ptr1 = NULL.join(ptr1);
+ Assert.assertEquals(TOP, NULL_join_ptr1);
+ Type NULL_join_PTR = PTR.join(NULL);
+ Assert.assertEquals(TOP, NULL_join_PTR);
+ Type ptr1_dual = ptr1.dual();
+ Type nullableptr1_dual = ptr1nil.dual();
+ }
+
+ // Test theoretical properties.
+ // This is a symmetric complete bounded (ranked) lattice.
+ // Also the meet is commutative and associative.
+ // The lattice has a dual (symmetric), and join is ~(~x meet ~y).
+ // See https://en.wikipedia.org/wiki/Lattice_(order).
+ @Test
+ public void testLatticeTheory() {
+ Type[] ts = Type.gather();
+
+ // Confirm commutative & complete
+ for( Type t0 : ts )
+ for( Type t1 : ts ) {
+ check_commute (t0,t1);
+ check_symmetric(t0,t1);
+ }
+
+ // Confirm associative
+ for( Type t0 : ts )
+ for( Type t1 : ts )
+ for( Type t2 : ts )
+ assoc(t0,t1,t2);
+
+ // Confirm symmetry. If A isa B, then A.join(C) isa B.join(C)
+ for( Type t0 : ts )
+ for( Type t1 : ts )
+ if( t0.isa(t1) )
+ for( Type t2 : ts ) {
+ Type t02 = t0.join(t2);
+ Type t12 = t1.join(t2);
+ Type mt = t02.meet(t12);
+ assertSame(mt,t12);
+ }
+ }
+
+ // By design in meet, args are already flipped to order _type, which forces
+ // symmetry for things with badly ordered _type fields. The question is
+ // still interesting for other orders.
+ private static void check_commute( Type t0, Type t1 ) {
+ if( t0==t1 ) return;
+ if( t0.is_simple() && !t1.is_simple() ) return; // By design, flipped the only allowed order
+ Type mta = t0.meet(t1);
+ Type mtb = t1.meet(t0); // Reverse args and try again
+ assertSame(mta,mtb);
+ }
+
+ // A & B = MT
+ // Expect: ~A & ~MT == ~A
+ // Expect: ~B & ~MT == ~B
+ private static void check_symmetric( Type t0, Type t1 ) {
+ if( t1==t0 ) return;
+ Type mt = t0.meet(t1);
+ Type ta = mt.dual().meet(t1.dual());
+ Type tb = mt.dual().meet(t0.dual());
+ assertSame(ta,t1.dual());
+ assertSame(tb,t0.dual());
+ }
+
+ private static void assoc( Type t0, Type t1, Type t2 ) {
+ Type t01 = t0 .meet(t1 );
+ Type t12 = t1 .meet(t2 );
+ Type t01_2 = t01.meet(t2 );
+ Type t0_12 = t0 .meet(t12);
+ assertSame(t01_2,t0_12);
+ }
+
+}
diff --git a/src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java b/src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java
new file mode 100644
index 00000000..3cf5c57b
--- /dev/null
+++ b/src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java
@@ -0,0 +1,209 @@
+package com.seaofnodes.simple.evaluator;
+
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.Field;
+import com.seaofnodes.simple.type.TypeInteger;
+import com.seaofnodes.simple.type.TypeMemPtr;
+import com.seaofnodes.simple.type.TypeStruct;
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.util.ArrayList;
+import java.util.BitSet;
+import java.util.Objects;
+
+public class Evaluator {
+
+ private static final Object MEMORY = new Object();
+
+ public record Obj(TypeStruct struct, Object[] fields) {
+ @Override
+ public String toString() {
+ var sb = new StringBuilder();
+ sb.append("Obj<").append(struct._name).append("> {");
+ for(int i=0; i<struct._fields.length; i++) {
+ sb.append("\n ").append(struct._fields[i]._fname).append("=").append(fields[i]);
+ }
+ return sb.append("\n}").toString();
+ }
+ }
+
+ private static int getFieldIndex(TypeStruct struct, MemOpNode memop) {
+ int idx = struct.find(memop._name);
+ if( idx >= 0 ) return idx;
+ throw new AssertionError("Field "+memop._name+" not found in struct " + struct._name);
+ }
+
+ public enum Status {
+ TIMEOUT,
+ FALLTHROUGH
+ }
+
+ /**
+ * Find the start node from some node in the graph or null if there is no start node
+ */
+ private static StartNode findStart(BitSet visit, Node node) {
+ if (node == null) return null;
+ if( visit.get(node._nid) ) return null;
+ visit.set(node._nid);
+ StartNode start = node instanceof StartNode ? (StartNode) node : null;
+ for( Node def : node._inputs ) {
+ var res = findStart(visit,def);
+ if( res != null ) start = res;
+ }
+ for( Node use : node._outputs ) {
+ var res = findStart(visit,use);
+ if( res != null ) start = res;
+ }
+ return start;
+ }
+
+ private final Object[] values;
+ private final ArrayList<Object> phiCache = new ArrayList<>();
+ private final StartNode start;
+ private final Scheduler.Block startBlock;
+
+ public Evaluator(Node graph) {
+ var visited = new BitSet();
+ this.start = findStart(visited, graph);
+ if (this.start == null) {
+ this.values = null;
+ this.startBlock = null;
+ return;
+ }
+ this.startBlock = Scheduler.schedule(this.start);
+ this.values = new Object[visited.length()];
+ }
+
+ private long div(DivNode div) {
+ long in2 = vall(div.in(2));
+ return in2 == 0 ? 0 : vall(div.in(1)) / in2;
+ }
+
+ private Object alloc(NewNode alloc) {
+ var type = ((TypeMemPtr)alloc.compute())._obj;
+ return new Obj(type, new Object[type._fields.length]);
+ }
+
+ private Object load(LoadNode load) {
+ var from = (Obj)val(load.in(2));
+ var idx = getFieldIndex(from.struct, load);
+ return from.fields[idx];
+ }
+
+ private Object store(StoreNode store) {
+ var to = (Obj)val(store.in(2));
+ var val = val(store.in(3));
+ var idx = getFieldIndex(to.struct, store);
+ to.fields[idx] = val;
+ return null;
+ }
+
+ private static boolean isTrue(Object obj) {
+ if (obj == null) return false;
+ if (obj instanceof Number n) return n.longValue() != 0;
+ return true;
+ }
+
+ private Object val(Node node) {
+ return values[node._nid];
+ }
+
+ private long vall(Node node) {
+ var v = val(node);
+ if (v instanceof Number n) return n.longValue();
+ throw new AssertionError("Not a long " + v);
+ }
+
+ private Object cons(ConstantNode cons) {
+ var type = cons.compute();
+ if (type instanceof TypeInteger i) return i.value();
+ assert type instanceof TypeMemPtr;
+ return null;
+ }
+
+ private Object exec(Node node) {
+ return switch (node) {
+ case ConstantNode cons -> cons(cons);
+ case AddNode add -> vall(add.in(1)) + vall(add.in(2));
+ case BoolNode.EQ eq -> Objects.equals(val(eq.in(1)), val(eq.in(2))) ? 1L : 0L;
+ case BoolNode.LE le -> vall(le.in(1)) <= vall(le.in(2)) ? 1L : 0L;
+ case BoolNode.LT lt -> vall(lt.in(1)) < vall(lt.in(2)) ? 1L : 0L;
+ case DivNode div -> div(div);
+ case MinusNode minus -> -vall(minus.in(1));
+ case MulNode mul -> vall(mul.in(1)) * vall(mul.in(2));
+ case NotNode not -> isTrue(val(not.in(1))) ? 0L : 1L;
+ case SubNode sub -> vall(sub.in(1)) - vall(sub.in(2));
+ case CastNode cast -> val(cast.in(1));
+ case LoadNode load -> load(load);
+ case StoreNode store -> store(store);
+ case NewNode alloc -> alloc(alloc);
+ case ProjNode proj -> ((Object[])val(proj.ctrl()))[proj._idx];
+ default -> throw new AssertionError("Unexpected node " + node);
+ };
+ }
+
+ /**
+ * Run the graph until either a return is found or the number of loop iterations are done.
+ */
+ public Object evaluate(long parameter, int loops) {
+ if (start == null) return Status.TIMEOUT;
+ var s = new Object[start.compute()._types.length];
+ s[1] = parameter;
+ for(int i=2;i<s.length;i++) s[i] = MEMORY;
+ values[start._nid] = s;
+ int i=0;
+ Scheduler.Block block = this.startBlock;
+ for(;;) {
+ for(; i<block.nodes().length;i++) values[block.nodes()[i]._nid] = exec(block.nodes()[i]);
+ i=0;
+ switch (block.exit()) {
+ case null:
+ return Status.FALLTHROUGH;
+ case ReturnNode ret:
+ return val(ret.in(1));
+ case IfNode ifn:
+ block = block.next()[isTrue(val(ifn.in(1))) ? 0 : 1];
+ if (block == null) return Status.FALLTHROUGH;
+ break;
+ case RegionNode region:
+ if (loops-- <= 0) return Status.TIMEOUT;
+ int exit = block.exitId();
+ assert exit > 0 && region.nIns() > exit;
+ block = block.next()[0];
+ assert block != null;
+ for (; i < block.nodes().length; i++) {
+ if (!(block.nodes()[i] instanceof PhiNode)) break;
+ phiCache.add(val(block.nodes()[i].in(exit)));
+ }
+ for (i=0; i<phiCache.size(); i++) {
+ values[block.nodes()[i]._nid] = phiCache.get(i);
+ }
+ phiCache.clear();
+ break;
+ default:
+ throw Utils.TODO("Unexpected control node " + block.exit());
+ }
+ }
+ }
+
+ public static Object evaluate(StopNode graph) {
+ return evaluate(graph, 0);
+ }
+
+ public static Object evaluate(StopNode graph, long parameter) {
+ return evaluate(graph, parameter, 1000);
+ }
+
+ public static Object evaluate(StopNode graph, long parameter, int loops) {
+ var res = evaluateWithResult(graph, parameter, loops);
+ if (res == Status.TIMEOUT) throw new RuntimeException("Timeout");
+ return res;
+ }
+
+ public static Object evaluateWithResult(StopNode graph, long parameter, int loops) {
+ return new Evaluator(graph).evaluate(parameter, loops);
+ }
+
+}
diff --git a/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java b/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java
new file mode 100644
index 00000000..674d12f5
--- /dev/null
+++ b/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java
@@ -0,0 +1,592 @@
+package com.seaofnodes.simple.evaluator;
+
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.Type;
+
+import java.util.*;
+
+/**
+ * A late scheduler for test cases.
+ * <br>
+ * <br>
+ * This scheduler is used for tests and is not the final scheduler.
+ * <br>
+ * <br>
+ * The scheduler schedules not as late as possible. Since it is just for test cases this is fine.
+ * A better scheduler will try to place nodes outside of loops. Due to the schedule late strategy
+ * this scheduler might place initialization code in loops.
+ * <br>
+ * We schedule late here since memory edges have some implicit information. There can only be one
+ * memory edge (for a field) at a time. However, before <code>if</code> statements this might split.
+ * When scheduling early a store might be moved out of the loop but then there are two edges alive.
+ * The one through the store node and the adjacent one. This is an invalid schedule and instead of
+ * handling this case a late scheduler does not have this problem as memory edges are combined
+ * through phi nodes.
+ * <br>
+ * <br>
+ * A bit about this scheduler. It first discovers all alive nodes and allocates side data for them.
+ * Then the control flow graph is build. Then, all phis are placed and finally all the remaining nodes
+ * in an order where a node is placed when all alive uses are placed. Finally, the output is produced.
+ */
+public class Scheduler {
+
+ /**
+ * A basic block with a schedule of the containing nodes.
+ *
+ * @param nodes The nodes in the final schedule of this block
+ * @param exit The exit node of this block.
+ * @param exitId In case the next block is a region this gives the entry id into the region.
+ * @param next The next blocks.
+ */
+ public record Block(Node[] nodes, Node exit, int exitId, Block[] next) {}
+
+ /**
+ * Definition of a block in the building process.
+ */
+ private static class BasicBlock {
+
+ /**
+ * Dominator of this block
+ */
+ final BasicBlock dom;
+ /**
+ * Id of this block where <code>a.depth < b.depth</code> means that a is before b or
+ * both are in different branches.
+ */
+ final int depth;
+ /**
+ * Previous blocks
+ */
+ final BasicBlock[] prev;
+ /**
+ * Entry to this block
+ */
+ final Node entry;
+ /**
+ * Schedules node in reverse order.
+ */
+ final ArrayList<Node> reverseSchedule = new ArrayList<>();
+
+ /**
+ * Initialize the block.
+ * @param entry The node that started this block
+ * @param depth The depth of this node. All previous nodes need to have a lower value.
+ * @param prev The previous blocks.
+ */
+ BasicBlock(Node entry, int depth, BasicBlock... prev) {
+ BasicBlock dom = null;
+ int max = -1;
+ for(var bb: prev) {
+ max = Math.max(max, bb.depth);
+ dom = dom==null?bb:dom(dom, bb);
+ }
+ assert depth > max;
+ this.dom = dom;
+ this.depth = depth;
+ this.entry = entry;
+ this.prev = prev;
+ }
+
+ }
+
+ /**
+ * Ancillary data for nodes used during the scheduling process.
+ */
+ private static class NodeData {
+
+ /**
+ * The node this ancillary data is used for.
+ */
+ final Node node;
+
+ /**
+ * Number of alive users not yet scheduled.
+ */
+ int users = 1;
+
+ /**
+ * Block into which the node should be placed so far.
+ * This will be updated with every placed use.
+ */
+ BasicBlock block;
+
+ /**
+ * Initialize ancillary data for a node
+ * @param node The node this ancillary data is associated with.
+ */
+ NodeData(Node node) {
+ this.node = node;
+ }
+
+ }
+
+ /**
+ * Ancillary data for nodes.
+ */
+ private final IdentityHashMap<Node, NodeData> data = new IdentityHashMap<>();
+ /**
+ * List of nodes which can be placed since all users are placed.
+ */
+ private final Stack<NodeData> scheduleQueue = new Stack<>();
+
+ /**
+ * Get the ancillary data for an alive node.
+ * @param node The node for which the ancillary data is requested.
+ * @return The ancillary data for the node.
+ */
+ NodeData d(Node node) {
+ return od(node).orElseThrow(AssertionError::new);
+ }
+
+ /**
+ * Get the ancillary data for a potentially dead node.
+ * @param node The node for which the ancillary data is requested.
+ * @return The ancillary data for the node an alive node or
+ * <code>Optional.empty()</code> for <code>null</code> or dead nodes.
+ */
+ Optional<NodeData> od(Node node) {
+ return Optional.ofNullable(data.get(node));
+ }
+
+ /**
+ * Checks a node for validity
+ * @param data The node to check.
+ * @return true if all placed inputs are before this node.
+ */
+ private boolean isValid(NodeData data) {
+ return data.node._inputs.stream().map(i->i==null?null:d(i)).map(d->d==null||d.users>0?null:d.block).allMatch(d->d==null||dom(d, data.block)==d);
+ }
+
+ /**
+ * Checks that node is not XCtrl.
+ * @param node The node to check.
+ * @return true if the node is not XCtrl.
+ */
+ private static boolean isNotXCtrl(Node node) {
+ return !(node instanceof ConstantNode c && c.compute() == Type.XCONTROL);
+ }
+
+ /**
+ * Return the dominator of <code>a</code> and <code>b</code>
+ * @param a Block a
+ * @param b Block b
+ * @return The dominator of <code>a</code> and <code>b</code>
+ */
+ private static BasicBlock dom(BasicBlock a, BasicBlock b) {
+ while (a!=b) {
+ if (a.depth >= b.depth) a=a.dom;
+ if (b.depth > a.depth) b=b.dom;
+ }
+ return a;
+ }
+
+ /**
+ * Return if a is before b.
+ * @param a Block a
+ * @param b Block b
+ * @return true is a is before b.
+ */
+ private static boolean isBefore(BasicBlock a, BasicBlock b) {
+ while (b.depth > a.depth) {
+ while (b.dom.depth > a.depth) b = b.dom;
+ for (int i=0; i<b.prev.length-1; i++) {
+ if (isBefore(a, b.prev[i])) return true;
+ }
+ b = b.prev[b.prev.length-1];
+ }
+ return a == b;
+ }
+
+ /**
+ * Is node placed during the control flow graph build.
+ * @param data Node to check.
+ * @return true if node is placed during the control flow graph build.
+ */
+ private static boolean isPinnedNode(NodeData data) {
+ return data.node.isCFG() || data.node instanceof PhiNode;
+ }
+
+ /**
+ * Refine placement of a node.
+ * @param data The node to refine.
+ * @param block The block before the node should be scheduled.
+ */
+ private void refinePlacement(NodeData data, BasicBlock block) {
+ assert !isPinnedNode(data);
+ data.block = data.block == null ? block : dom(data.block, block);
+ assert isValid(data);
+ }
+
+ /**
+ * Refine placement if before is happening before data
+ * @param data The node for which the placement should be refined.
+ * @param before The node before which the data node should be placed.
+ */
+ private void optionalRefinePlacement(NodeData data, Node before) {
+ od(before).ifPresent(d->{
+ // before might be in a different branch. So check this case with isBefore
+ // and only refine the placement if it is not in a different branch.
+ if (isBefore(d.block, data.block)) refinePlacement(data, d.block);
+ });
+ }
+
+ /**
+ * Schedule all nodes not yet scheduled.
+ */
+ private void doSchedule() {
+ while (!scheduleQueue.isEmpty()) {
+ var data = scheduleQueue.pop();
+ assert !isPinnedNode(data);
+
+ assert data.block != null;
+ assert data.users == 0;
+
+ if (data.node instanceof LoadNode l) {
+ assert isValid(data);
+ // Handle anti-deps of load nodes.
+ // At this point all anti-dep nodes are scheduled,
+ // but they did not refine the placement
+ // so do that now.
+ var mem = l.in(1);
+ for(var out : mem._outputs) {
+ if (out instanceof PhiNode p) {
+ var r = p.in(0);
+ for (int i = 1; i < p.nIns(); i++) {
+ if (p.in(i) == mem) optionalRefinePlacement(data, r.in(i));
+ }
+ } else if (!(out instanceof LoadNode)) {
+ optionalRefinePlacement(data, out);
+ }
+ }
+ }
+
+ assert isValid(data);
+ data.block.reverseSchedule.add(data.node);
+
+ for(var in:data.node._inputs) {
+ if (in!=null) update(d(in), data.block);
+ }
+ if (data.node instanceof StoreNode s) {
+ // Store nodes have anti-deps to load nodes.
+ // So decrease the uses of these loads when the store is placed.
+ for (var out: s.in(1)._outputs) {
+ if (out instanceof LoadNode) od(out).ifPresent(this::decUsers);
+ }
+ }
+ }
+
+ // Now all nodes should be placed and have a block assigned
+ assert this.data.values().stream().noneMatch(d->d.block==null);
+ }
+
+ /**
+ * Decrement the not-yet-placed users of a block.
+ * @param data The node for which the users should be decremented.
+ */
+ private void decUsers(NodeData data) {
+ assert data.users > 0;
+ if (--data.users == 0) {
+ assert data.block != null;
+ assert isValid(data);
+
+ // When all users are gone this node can be scheduled.
+ scheduleQueue.push(data);
+ }
+ }
+
+ /**
+ * Update the placement of a node
+ * @param data The node to update
+ * @param block The block before which the node should happen.
+ */
+ private void update(NodeData data, BasicBlock block) {
+ assert block != null;
+ if (data.users == 0) {
+ assert isPinnedNode(data);
+ return;
+ }
+ refinePlacement(data, block);
+ decUsers(data);
+ }
+
+ /**
+ * Checks if a CFG node is ready to be placed. This is used for regions joining branches.
+ * @param node The CFG node to check
+ * @return true if all parents of a CFG node are placed.
+ */
+ private boolean isCFGNodeReady(Node node) {
+ if (node instanceof LoopNode l) {
+ assert d(l.in(1)).block != null;
+ } else if (node instanceof RegionNode r) {
+ for(int i=1; i<r.nIns(); i++) {
+ if (od(r.in(i)).map(d->d.block==null).orElse(false)) return false;
+ }
+ } else {
+ assert d(node.in(0)).block != null;
+ }
+ return true;
+ }
+
+ /**
+ * Schedule all phi nodes.
+ * @param phiQueue List of all the phi nodes to schedule.
+ */
+ private void schedulePhis(Stack<NodeData> phiQueue) {
+ while(!phiQueue.empty()) {
+ var data = phiQueue.pop();
+ var phi = (PhiNode) data.node;
+ var r = phi.in(0);
+ data.block = d(r).block;
+ for(int i=1; i<phi.nIns(); i++) {
+ var in = phi.in(i);
+ od(r.in(i)).ifPresent(d->update(d(in), d.block));
+ }
+ }
+ }
+
+ /**
+ * Build the control flow graph.
+ * @param start The start node.
+ */
+ private void doBuildCTF(StartNode start) {
+ var queue = new Stack<NodeData>();
+ var phiQueue = new Stack<NodeData>();
+ queue.push(d(start));
+ int depth = 0;
+ while (!queue.isEmpty()) {
+ var data = queue.pop();
+ var node = data.node;
+ assert node.isCFG();
+ BasicBlock block;
+ switch (node) {
+ case StartNode s:
+ block = new BasicBlock(s, depth++);
+ break;
+ case LoopNode l:
+ block = new BasicBlock(l, depth++, d(l.in(1)).block);
+ break;
+ case RegionNode r:
+ var prev = new ArrayList<BasicBlock>();
+ for(int i=1; i<r.nIns(); i++) {
+ od(r.in(i)).ifPresent(d->prev.add(d.block));
+ }
+ block = new BasicBlock(r, depth++, prev.toArray(BasicBlock[]::new));
+ break;
+ case IfNode i:
+ block = d(i.in(0)).block;
+ break;
+ case ReturnNode r:
+ block = d(r.in(0)).block;
+ break;
+ default:
+ block = new BasicBlock(node, depth++, d(node.in(0)).block);
+ }
+ data.block = block;
+ if (node instanceof RegionNode r) {
+ // Regions might have phis which need to be scheduled.
+ // Put them on a list for later scheduling.
+ for (var out:r._outputs) {
+ if (out instanceof PhiNode p) {
+ var d = this.data.get(p);
+ if (d!=null) {
+ d.users=0;
+ phiQueue.push(d);
+ }
+ }
+ }
+ }
+ if (!(node instanceof ReturnNode))
+ for (Node n:node._outputs) if (n.isCFG() && isCFGNodeReady(n) && d(n).block == null) queue.push(d(n));
+ var b = block;
+ for(var in:data.node._inputs) od(in).ifPresent(d->update(d, b));
+ }
+
+ // Schedule all phi nodes.
+ schedulePhis(phiQueue);
+ }
+
+ /**
+ * Mark a node alive and create ancillary data for it.
+ * @param queue List into which this node should be placed if it needs to be visited.
+ * @param node Node which should be marked alive.
+ * @param cfg If this node is a CFG node.
+ */
+ private void markAlive(Stack<NodeData> queue, Node node, boolean cfg) {
+ var nd = od(node).orElse(null);
+ if (nd != null) {
+ // Node was already visited, just increase the users.
+ if (nd.users>0) nd.users++;
+ return;
+ }
+ assert node.isCFG() == cfg;
+ assert isNotXCtrl(node);
+ nd = new NodeData(node);
+ if (cfg) nd.users=0;
+ data.put(node, nd);
+ queue.push(nd);
+ }
+
+ /**
+ * Mark all alive nodes.
+ * First all CFG nodes are marked, then all other nodes.
+ * @param node THe start node.
+ */
+ private void doMarkAlive(Node node) {
+ var cfgQueue = new Stack<NodeData>();
+ var dataQueue = new Stack<NodeData>();
+ var mem = new Stack<NodeData>();
+ markAlive(cfgQueue, node, true);
+ // Mark all CFG nodes.
+ while (!cfgQueue.isEmpty()) {
+ var data = cfgQueue.pop();
+ node = data.node;
+ assert node.isCFG();
+ if (!(node instanceof ReturnNode)) {
+ for (var out : node._outputs) if (out.isCFG() && isNotXCtrl(out)) markAlive(cfgQueue, out, true);
+ }
+ for (var in : node._inputs) if(in!=null && !in.isCFG() && isNotXCtrl(in)) markAlive(dataQueue, in, false);
+ }
+ // Mark all other nodes.
+ while (!dataQueue.isEmpty()) {
+ var data = dataQueue.pop();
+ node = data.node;
+ assert !node.isCFG();
+ if (node instanceof PhiNode phi) {
+ var r = phi.in(0);
+ for (int i=1; i<phi.nIns(); i++) {
+ if (od(r.in(i)).isPresent()) markAlive(dataQueue, phi.in(i), false);
+ }
+ } else {
+ for (var in : node._inputs) if (in != null && !in.isCFG()) markAlive(dataQueue, in, false);
+ }
+ if (node instanceof StoreNode) mem.push(data);
+ }
+ // Handle store nodes and increase load with an anti-dep to the store.
+ while (!mem.isEmpty()) {
+ var data = mem.pop();
+ node = data.node;
+ for(var out:node.in(1)._outputs) {
+ if (out instanceof LoadNode) od(out).ifPresent(d->d.users++);
+ }
+ }
+ }
+
+ /**
+ * Helper function to append the nodes of a block to an array of nodes
+ * @param arr The array the nodes of a block should be appended to.
+ * @param node A potentially separator node
+ * @param block The block from which the nodes should be appended.
+ * @return The combined new array.
+ */
+ private static Node[] appendNodes(Node[] arr, Node node, BasicBlock block) {
+ var idx = arr.length;
+ arr = Arrays.copyOf(arr, arr.length+block.reverseSchedule.size()+(node==null?0:1));
+ if (node != null) arr[idx++] = node;
+ for(int i=block.reverseSchedule.size()-1;i>=0;i--) {
+ arr[idx++] = block.reverseSchedule.get(i);
+ }
+ return arr;
+ }
+
+ /**
+ * Find the CFG output of a node
+ * @param node The node
+ * @return THe CFG output of the node.
+ */
+ private static Node findSingleCFGOut(Node node) {
+ if (node instanceof StartNode) {
+ for(var n:node._outputs) if (n instanceof ProjNode p && p._idx==0) return p;
+ return null;
+ }
+ assert node._outputs.stream().filter(Node::isCFG).limit(2).count()<=1;
+ for(var n:node._outputs) if(n.isCFG()) return n;
+ return null;
+ }
+
+ /**
+ * Build the final data structure after all the scheduling happened.
+ * @param start The start node
+ * @return The final schedule.
+ */
+ private Block build(Node start) {
+ var blocks = new IdentityHashMap<Node, Block>();
+ var queue = new Stack<NodeData>();
+ queue.push(d(start));
+
+ // Visit all CFG nodes and create blocks for them.
+ // This can combine blocks.
+ while(!queue.isEmpty()) {
+ var data = queue.pop();
+ var first = data.node;
+ Node prev;
+ var last = first;
+ Node[] arr = new Node[0];
+ if (first instanceof RegionNode) {
+ var nodes = new ArrayList<Node>();
+ for(var out: first._outputs) {
+ if (out instanceof PhiNode) {
+ if(od(out).isPresent()) nodes.add(out);
+ }
+ }
+ arr = nodes.toArray(arr);
+ }
+ arr = appendNodes(arr, null, data.block);
+ assert !(first instanceof IfNode);
+ for(;;) {
+ prev = last;
+ last = findSingleCFGOut(last);
+ if (last == null) break;
+ if (last instanceof RegionNode) {
+ if (blocks.get(last) == null && last != first)
+ queue.push(d(last));
+ break;
+ }
+ if (last instanceof ReturnNode) break;
+ if (last instanceof IfNode if_) {
+ for(var out:if_._outputs) if (out.isCFG() && blocks.get(out) == null) queue.push(d(out));
+ break;
+ }
+ data = d(last);
+ arr = appendNodes(arr, data.node, data.block);
+ }
+ blocks.put(first, switch(last) {
+ case null -> new Block(arr, null, -1, new Block[0]);
+ case IfNode i -> new Block(arr, i, -1, new Block[2]);
+ case RegionNode r -> new Block(arr, r, Utils.find(r._inputs, prev), new Block[1]);
+ case ReturnNode r -> new Block(arr, r, -1, new Block[0]);
+ default -> throw new AssertionError("Unexpected block exit node");
+ });
+ }
+ // Update the next pointer of all blocks.
+ for (var block: blocks.values()) {
+ switch(block.exit) {
+ case null: break;
+ case IfNode i:
+ for(var out:i._outputs) if (out instanceof ProjNode p) block.next[p._idx] = blocks.get(p);
+ break;
+ case RegionNode r:
+ block.next[0] = blocks.get(r);
+ break;
+ default:
+ assert block.exit instanceof ReturnNode;
+ }
+ }
+ // And return the block for the start node.
+ return blocks.get(start);
+ }
+
+ /**
+ * Create a schedule for the program reachable from start.
+ * @param start The start node
+ * @return The final schedule.
+ */
+ public static Scheduler.Block schedule(StartNode start) {
+ var scheduler = new Scheduler();
+ scheduler.doMarkAlive(start);
+ scheduler.doBuildCTF(start);
+ scheduler.doSchedule();
+ return scheduler.build(start);
+ }
+
+}
diff --git a/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java b/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java
index 936fb41e..51e39cd0 100644
--- a/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java
+++ b/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java
@@ -1,11 +1,12 @@
package com.seaofnodes.simple.fuzzer;
-import com.seaofnodes.simple.GraphEvaluator;
import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.evaluator.Evaluator;
import com.seaofnodes.simple.node.Node;
import com.seaofnodes.simple.node.StopNode;
import java.util.ArrayList;
+import java.util.Objects;
import java.util.Random;
import java.util.function.Consumer;
@@ -36,13 +37,15 @@ public class Fuzzer {
* @param script The script causing the exception
* @param reproducer Reproducer which should be used to reproduce the test case.
*/
- private void recordException(Throwable e, String script, Consumer<String> reproducer) {
+ private void recordException(Throwable e, String script, Consumer<String> reproducer, long seed) {
for (var ex : exceptions) {
if (FuzzerUtils.isExceptionFromSameCause(ex, e)) return;
}
exceptions.add(e);
System.out.println("========== Stack ==========");
e.printStackTrace(System.out);
+ System.out.println("========== Seed ==========");
+ System.out.println(seed);
System.out.println("========== Code ===========");
System.out.println(script);
System.out.println("========= Reduced =========");
@@ -51,20 +54,30 @@ public class Fuzzer {
System.out.flush();
}
+ private static boolean neq(Object a, Object b) {
+ if (Objects.equals(a, b)) return false;
+ if (a instanceof Evaluator.Obj ea && b instanceof Evaluator.Obj eb) {
+ if (ea.struct() != eb.struct()) return true;
+ for(int i=0;i<ea.fields().length;i++) {
+ if (neq(ea.fields()[i], eb.fields()[i])) return true;
+ }
+ return false;
+ }
+ return true;
+ }
+
/**
* Check that two graphs result in the same output when supplied with a value
- * @param stop1 Stop node of the first graph
- * @param stop2 Stop node of the second graph
+ * @param e1 Evaluator for the first graph
+ * @param e2 Evaluator for the second graph
* @param in The input value to both graphs to test for an equal output
*/
- private static void checkGraphs(StopNode stop1, StopNode stop2, long in) {
- var e1 = GraphEvaluator.evaluateWithResult(stop1, in, EVAL_TIMEOUT);
- var e2 = GraphEvaluator.evaluateWithResult(stop2, in, EVAL_TIMEOUT);
- if (e1.type() == GraphEvaluator.ResultType.TIMEOUT || e2.type() == GraphEvaluator.ResultType.TIMEOUT) return;
- if (e1.type() != e2.type())
- throw new RuntimeException("Different calculations types " + e1.type() + " vs " + e2.type());
- if (e1.value() != e2.value())
- throw new RuntimeException("Different calculations values " + e1.value() + " vs " + e2.value());
+ private static void checkGraphs(Evaluator e1, Evaluator e2, long in) {
+ var r1 = e1.evaluate(in, EVAL_TIMEOUT);
+ var r2 = e2.evaluate(in, EVAL_TIMEOUT);
+ if (r1 == Evaluator.Status.TIMEOUT || r2 == Evaluator.Status.TIMEOUT) return;
+ if (neq(r1, r2))
+ throw new RuntimeException("Different calculations values " + r1 + " vs " + r2);
}
/**
@@ -91,9 +104,11 @@ public class Fuzzer {
throw e1;
}
var stop2 = FuzzerUtils.parse(script, true);
- checkGraphs(stop1, stop2, 0);
- checkGraphs(stop1, stop2, 1);
- checkGraphs(stop1, stop2, 10);
+ var e1 = new Evaluator(stop1);
+ var e2 = new Evaluator(stop2);
+ checkGraphs(e1, e2, 0);
+ checkGraphs(e1, e2, 1);
+ checkGraphs(e1, e2, 10);
}
/**
@@ -101,11 +116,11 @@ public class Fuzzer {
* @param script The script to test.
* @param valid If the script is valid or if it might contain syntax errors.
*/
- private void check(String script, boolean valid) {
+ private void check(String script, boolean valid, long seed) {
try {
runCheck(script, valid);
} catch (Throwable e) {
- recordException(e, script, s->runCheck(s, valid));
+ recordException(e, script, s->runCheck(s, valid), seed);
}
}
@@ -155,8 +170,8 @@ public class Fuzzer {
public void fuzzPeeps(long seed) {
var rand = new Random(seed);
var sb = new StringBuilder();
- var valid = new ScriptGenerator(rand, sb, false).genProgram();
- check(sb.toString(), valid);
+ var valid = new ScriptGenerator(rand, sb, true).genProgram();
+ check(sb.toString(), valid, seed);
}
diff --git a/src/test/java/com/seaofnodes/simple/fuzzer/FuzzerUtils.java b/src/test/java/com/seaofnodes/simple/fuzzer/FuzzerUtils.java
index f13a51e1..18ef069a 100644
--- a/src/test/java/com/seaofnodes/simple/fuzzer/FuzzerUtils.java
+++ b/src/test/java/com/seaofnodes/simple/fuzzer/FuzzerUtils.java
@@ -18,7 +18,7 @@ import java.util.BitSet;
class FuzzerUtils {
/**
- * Get the value of a private field
+ * Get the val of a private field
*/
@SuppressWarnings("unchecked")
public static <T> T getFieldValue(Object obj, String name) throws NoSuchFieldException, IllegalAccessException {
@@ -74,10 +74,12 @@ class FuzzerUtils {
}
/**
- * Check that eiter one of the objects is null or that both are equal.
+ * Check that the messages are similar.
*/
- private static boolean equalOrNull(Object a, Object b) {
+ private static boolean similarMessages(String a, String b) {
if (a == null || b == null) return true;
+ a = a.replaceAll("'\\w+'", "'normalized'").replaceAll("variable \\w+", "variable normalized");
+ b = b.replaceAll("'\\w+'", "'normalized'").replaceAll("variable \\w+", "variable normalized");
return a.equals(b);
}
@@ -96,7 +98,7 @@ class FuzzerUtils {
public static boolean isExceptionFromSameCause(Throwable a, Throwable b) {
if (a == null || b == null) return a == b; // Handle the null case
if (a.getClass() != b.getClass()) return false; // Different classes
- if (!equalOrNull(a.getMessage(), b.getMessage())) return false; // Different messages. Null is allowed as wildcard
+ if (!similarMessages(a.getMessage(), b.getMessage())) return false; // Different messages. Null is allowed as wildcard
var s1 = a.getStackTrace();
var s2 = b.getStackTrace();
if (!sameStackTraceOrigin(s1, s2)) return false; // Different stack trace origins
diff --git a/src/test/java/com/seaofnodes/simple/fuzzer/Reducer.java b/src/test/java/com/seaofnodes/simple/fuzzer/Reducer.java
index 2ef0a3fd..3731b40c 100644
--- a/src/test/java/com/seaofnodes/simple/fuzzer/Reducer.java
+++ b/src/test/java/com/seaofnodes/simple/fuzzer/Reducer.java
@@ -1,7 +1,10 @@
package com.seaofnodes.simple.fuzzer;
+import java.util.Arrays;
+import java.util.function.BiConsumer;
import java.util.function.Consumer;
import java.util.function.Predicate;
+import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
@@ -13,35 +16,45 @@ import java.util.regex.Pattern;
*/
public class Reducer {
+ private interface Replacer extends BiConsumer<StringBuilder, Matcher> {}
+
/**
* Holder for the rewrite rules
*/
- private record Replace(Pattern p, String r) {}
+ private record Replace(Pattern pattern, boolean iterate, Replacer... replacements) {
+ Replace(Pattern p, Object... replacements) {
+ this(p, replacements[0] == Boolean.TRUE, Arrays.stream(replacements).filter(o->!(o instanceof Boolean)).map(Replace::from).toArray(Replacer[]::new));
+ }
+ private static Replacer from(Object o) {
+ if (o instanceof Replacer r) return r;
+ if (o instanceof Integer i) return (s, m)->s.append(m.group(i));
+ if (o instanceof String r) return (s, m)->s.append(r);
+ throw new IllegalArgumentException();
+ }
+ }
/**
* List of rewrite rules.
*/
private static final Replace[] REPLACEMENTS = {
+ new Replace(Pattern.compile("\\b(?:[^\\W0]|\\w\\w+)\\b"), "0", "1"),
+ new Replace(Pattern.compile("(?<=\\n|^)[^\\n]+(?=\\n|$)"), true, ""),
new Replace(Pattern.compile("(?<=[+\\-*/<>=(])--"), ""),
new Replace(Pattern.compile("\\b--"), "+"),
- new Replace(Pattern.compile("\\b\\+-"), "-"),
- new Replace(Pattern.compile("\\bfalse\\b"), "0"),
- new Replace(Pattern.compile("\\btrue\\b"), "1"),
new Replace(Pattern.compile("-"), ""),
+ new Replace(Pattern.compile("\\b\\+-"), "-"),
new Replace(Pattern.compile("(?<![+\\-*/<>=])(?:-|\\*|/|>=|<=|>|<|!=|==)(?![+\\-*/<>=])"), "+"),
- new Replace(Pattern.compile("\\{(?:[^{}]|\\{})+}"), "{}"),
- new Replace(Pattern.compile("\\{((?:[^{}]|\\{})+)}"), "$1"),
- new Replace(Pattern.compile("\\(([^()]+)\\)"), "$1"),
- new Replace(Pattern.compile("\\b\\w+\\b"), "0"),
- new Replace(Pattern.compile("\\b(?:[^\\W0]|\\w\\w+)\\b"), "1"),
+ new Replace(Pattern.compile("\\{((?:[^{}]|\\{})+)(?:\\n[ \\t]*)?}"), "", "{}", 1),
+ new Replace(Pattern.compile("(?<=\\n|^)([ \\t]*)\\{\\n(.*?)\\n\\1}", Pattern.DOTALL), 2),
+ new Replace(Pattern.compile("\\(([^()]+)\\)"), 1),
new Replace(Pattern.compile("\\d+\\+"), ""),
new Replace(Pattern.compile("\\+\\d+"), ""),
- new Replace(Pattern.compile("(?<=\\n|^)[^\\n]*(?=\\n|$)"), "\n"),
- new Replace(Pattern.compile("\\n+"), "\n"),
+ new Replace(Pattern.compile("\\n\\n+"), "\n"),
new Replace(Pattern.compile("^\\n+|\\n+$"), ""),
new Replace(Pattern.compile("else *"), ""),
new Replace(Pattern.compile("\\bif\\([^()]+\\) *"), ""),
new Replace(Pattern.compile("\\bwhile\\([^()]+\\) *"), ""),
+ new Replace(Pattern.compile("\\bstruct \\w+ \\{[^{}]*}"), "")
};
/**
@@ -60,24 +73,31 @@ public class Reducer {
/**
* Rewrites the script with one rewrite rule.
*/
- private String doReplacement(String script, Pattern pattern, String with) {
+ private String doReplacement(String script, Pattern pattern, Replacer[] replacements) {
var matcher = pattern.matcher(script);
var sb = new StringBuilder();
- int last = 0;
- while (matcher.find()) {
+ var last = 0;
+ var skip = 0;
+ outer:
+ while (matcher.find(last + skip)) {
+ sb.append(script, last, matcher.start());
+ last = matcher.end();
+ skip = last == matcher.start() ? 1 : 0;
var pos = sb.length();
- matcher.appendReplacement(sb, with);
- var tail = sb.length();
- matcher.appendTail(sb);
- if (tester.test(sb.toString())) {
- sb.setLength(tail);
- } else {
+ for (var replacement : replacements) {
+ replacement.accept(sb, matcher);
+ var tail = sb.length();
+ sb.append(script, last, script.length());
+ if (tester.test(sb.toString())) {
+ sb.setLength(tail);
+ continue outer;
+ }
sb.setLength(pos);
- sb.append(script, last, matcher.end());
}
- last = matcher.end();
+ last = matcher.start();
+ skip = 1;
}
- matcher.appendTail(sb);
+ sb.append(script, last, script.length());
return sb.toString();
}
@@ -85,13 +105,21 @@ public class Reducer {
* Clean up variable names from the random ones generated by the fuzzer.
*/
private String cleanVariables(String script) {
- var matcher = Pattern.compile("\\bint ([0-9a-zA-Z_]+)").matcher(script);
- int num = 0;
+ var matcher = Pattern.compile("\\b([0-9a-zA-Z_]+) ([0-9a-zA-Z_]+)").matcher(script);
+ int[] num = {0, 0};
while (matcher.find()) {
- var var = matcher.group(1);
- if (var.matches("v\\d+")) continue;
- while (script.contains("v"+num)) num++;
- var n = script.replaceAll("\\b"+var+"\\b", "v" + num);
+ var type = matcher.group(1);
+ var var = matcher.group(2);
+ if (type.equals("new")) continue;
+ String prefix = "v";
+ int t = 0;
+ if (type.equals("struct")) {
+ t = 1;
+ prefix = "s";
+ }
+ if (var.matches(prefix+"\\d+")) continue;
+ while (script.contains(prefix+num[t])) num[t]++;
+ var n = script.replaceAll("\\b"+var+"\\b", prefix + num[t]);
if (tester.test(n)) {
script = n;
}
@@ -104,7 +132,11 @@ public class Reducer {
*/
private String doAllReplacements(String script) {
for (var replace: REPLACEMENTS) {
- script = doReplacement(script, replace.p, replace.r);
+ String old;
+ do {
+ old = script;
+ script = doReplacement(script, replace.pattern, replace.replacements);
+ } while (replace.iterate && !old.equals(script));
}
return script;
}
diff --git a/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java b/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java
index ad98f7e2..155063ab 100644
--- a/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java
+++ b/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java
@@ -6,6 +6,7 @@ import com.seaofnodes.simple.node.ScopeNode;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Random;
+import java.util.function.Predicate;
/**
* Generate a pseudo random script.
@@ -15,6 +16,13 @@ import java.util.Random;
*/
public class ScriptGenerator {
+ private static final int MAX_STATEMENTS_PER_BLOCK = 5;
+ private static final int MAX_BINARY_EXPRESSIONS_PER_EXPRESSION = 10;
+ private static final int MAX_UNARY_EXPRESSIONS_PER_EXPRESSION = 6;
+ private static final int MAX_NAME_LENGTH = 10;
+ private static final int MAX_BLOCK_DEPTH = 4;
+ private static final int MAX_EXPRESSION_DEPTH = 10;
+
/**
* Number of spaces per indentation
*/
@@ -53,6 +61,51 @@ public class ScriptGenerator {
*/
private static final String[] UNARY_OP = {"-"};
+ private static class Type {
+ final String name;
+ Type(String name) {this.name=name;}
+ boolean isa(Type other) { return this == other; }
+ }
+
+ private static class TypeStruct extends Type {
+ record Field (String name, Type type) {}
+ final Field[] fields;
+ final TypeNullable nullable = new TypeNullable(this);
+ TypeStruct(String name, Field[] fields) {
+ super(name);
+ this.fields = fields;
+ }
+ boolean isa(Type other) { return this == other || other == nullable; }
+ }
+
+ private static class TypeNullable extends Type {
+
+ final Type base;
+
+ TypeNullable(Type base) {
+ super(base.name+"?");
+ this.base = base;
+ }
+
+ }
+
+ private static final Type TYPE_INT = new Type("int");
+
+
+ private static class Variable {
+ final String name;
+ final Type declared;
+ final Variable shadowing;
+ Type type;
+ boolean shadowed = false;
+
+ Variable(String name, Type type, Variable var) {
+ this.name = name;
+ this.declared = type;
+ this.type = type;
+ this.shadowing = var;
+ }
+ }
/**
* The random number generator used for random decisions.
@@ -77,24 +130,33 @@ public class ScriptGenerator {
/**
* The depth of blocks allowed.
*/
- private int depth = 20;
+ private int depth = MAX_BLOCK_DEPTH;
/**
* The depth of expressions allowed.
*/
- private int exprDepth = 30;
+ private int exprDepth = MAX_EXPRESSION_DEPTH;
/**
* Current variables in scope.
*/
- private final ArrayList<String> variables = new ArrayList<>();
+ private final ArrayList<Variable> variables = new ArrayList<>();
+ /**
+ * All defined structs.
+ */
+ private final ArrayList<TypeStruct> structs = new ArrayList<>();
+ /**
+ * Allow to declare structs.
+ */
+ private boolean allowStructs = true;
/**
* If this needs to generate valid scripts or is also allowed to generate invalid ones.
*/
- private final boolean generateValid;
+ private boolean generateValid;
/**
* If this script might be invalid.
*/
private boolean maybeInvalid = false;
+
/**
*
* @param random the random number generator.
@@ -135,7 +197,7 @@ public class ScriptGenerator {
* @return The random name generated
*/
private StringBuilder getRandomName() {
- int len = random.nextInt(30) + 1;
+ int len = random.nextInt(MAX_NAME_LENGTH) + 1;
StringBuilder sb = new StringBuilder(len);
sb.append(VAR_CHARS.charAt(random.nextInt(VAR_CHARS.length()-10)));
for (int i=1; i<len; i++)
@@ -144,6 +206,90 @@ public class ScriptGenerator {
}
/**
+ * Should invalid code be generated?
+ * @return True if invalid code should be generated
+ */
+ private boolean generateInvalid() {
+ if (generateValid || random.nextInt(1000)>2) return false;
+ maybeInvalid = true;
+ return true;
+ }
+
+ /**
+ * Lookup a variable by name
+ * @param name name of the variable
+ * @return The index of the variable in variables or -1
+ */
+ private int lookup(String name) {
+ for (int i=variables.size()-1; i>=0; i--) {
+ if (variables.get(i).name.equals(name)) return i;
+ }
+ return -1;
+ }
+
+ /**
+ * Lookup a variable by name
+ * @param name name of the variable
+ * @return THe variable of null if not found
+ */
+ private Variable lookupVar(String name) {
+ int idx = lookup(name);
+ return idx == -1 ? null : variables.get(idx);
+ }
+
+ /**
+ * Add a variable to the current scope
+ * @param name The name of the variable
+ * @param type The declared type of the variable
+ */
+ private void addVariable(String name, Type type) {
+ var old = lookupVar(name);
+ variables.add(new Variable(name, type, old));
+ if (old != null) old.shadowed = true;
+ }
+
+ /**
+ * Pop variables to level to
+ * @param to Level until which variables should be popped
+ */
+ private void popVariables(int to) {
+ while (variables.size() > to) {
+ var v = variables.removeLast();
+ if (v.shadowing != null) v.shadowing.shadowed = false;
+ }
+ }
+
+ /**
+ * Get a random visible variable patching pred
+ * @param pred The predicate the variable needs to match
+ * @return A random visible variable matching pred or null if no variable mached pred.
+ */
+ private Variable findVisibleVariablesMatching(Predicate<Variable> pred) {
+ int num=0;
+ for (var v:variables) {
+ if (!v.shadowed && pred.test(v)) num++;
+ }
+ if (num == 0) return null;
+ num = random.nextInt(num);
+ for (var v:variables) {
+ if (!v.shadowed && pred.test(v) && num-- == 0) return v;
+ }
+ throw new AssertionError();
+ }
+
+ /**
+ * Get a structure by name
+ * @param name Name of the structure
+ * @return The structure of null
+ */
+ private TypeStruct getStruct(String name) {
+ for (var s:structs) {
+ if (s.name.equals(name)) return s;
+ }
+ return null;
+ }
+
+ /**
* Generate a variable name. This might be new random name or a name from an outer scope.
* If the program is allowed to be invalid this can return keywords and already used variable names in the current scope.
* @return The variable name.
@@ -152,35 +298,67 @@ public class ScriptGenerator {
if (currScopeStart > 0 && random.nextInt(10) > 7) {
// Use a variable outside the current scope.
var v = variables.get(random.nextInt(currScopeStart));
- if (variables.lastIndexOf(v) < currScopeStart) return v;
+ if (lookup(v.name) < currScopeStart) return v.name;
if (!generateValid) {
maybeInvalid = true;
- return v;
+ return v.name;
}
}
// Generate a new random variable name
StringBuilder sb = getRandomName();
var v = sb.toString();
- if (!generateValid && (KEYWORDS.contains(v) || variables.lastIndexOf(v) >= currScopeStart)) {
+ if (!generateValid && (KEYWORDS.contains(v) || lookup(v) >= currScopeStart)) {
maybeInvalid = true;
return v;
}
- while (KEYWORDS.contains(v) || variables.lastIndexOf(v) >= currScopeStart) {
+ while (KEYWORDS.contains(v) || lookup(v) >= currScopeStart) {
sb.append(VAR_CHARS.charAt(random.nextInt(VAR_CHARS.length())));
v = sb.toString();
}
return v;
}
+ /**
+ * Get a random structure name
+ * @return A random structure name
+ */
+ private String getStructName() {
+ if (!structs.isEmpty() && generateInvalid()) return structs.get(random.nextInt(structs.size())).name;
+ // Generate a new random struct name
+ StringBuilder sb = getRandomName();
+ var v = sb.toString();
+ if (!generateValid && (KEYWORDS.contains(v) || getStruct(v) != null)) {
+ maybeInvalid = true;
+ return v;
+ }
+ while (KEYWORDS.contains(v) || getStruct(v) != null) {
+ sb.append(VAR_CHARS.charAt(random.nextInt(VAR_CHARS.length())));
+ v = sb.toString();
+ }
+ return v;
+ }
+ /**
+ * Get a random type
+ * @return A random type
+ */
+ private Type getType() {
+ if (structs.isEmpty() || random.nextBoolean()) return TYPE_INT;
+ var idx = random.nextInt(structs.size());
+ TypeStruct struct = structs.get(idx);
+ if (random.nextBoolean()) return struct.nullable;
+ return struct;
+ }
/**
* Generates a program and writes it into the string builder supplied in the constructor.
* @return If the program is allowed to be invalid returns if something potentially invalid was generated.
*/
public boolean genProgram() {
+ var oldGenerateValid = generateValid;
+ if (!generateValid && random.nextBoolean()) generateValid = true;
this.maybeInvalid = false;
- variables.add(ScopeNode.ARG0);
+ addVariable(ScopeNode.ARG0, TYPE_INT);
currScopeStart = variables.size();
if ((genStatements() & FLAG_STOP) == 0) {
if (generateValid || random.nextInt(10)<7) {
@@ -189,6 +367,7 @@ public class ScriptGenerator {
this.maybeInvalid = true;
}
}
+ generateValid = oldGenerateValid;
return !this.maybeInvalid;
}
@@ -197,7 +376,7 @@ public class ScriptGenerator {
* @return flags FLAG_STOP and FLAG_IF_WITHOUT_ELSE for the last statement generated
*/
public int genStatements() {
- var num = random.nextInt(10); // (30);
+ var num = random.nextInt(MAX_STATEMENTS_PER_BLOCK * (depth+1));
for (int i=0; i<num; i++) {
printIndentation();
var stop = genStatement();
@@ -212,29 +391,55 @@ public class ScriptGenerator {
* @return flags FLAG_STOP and FLAG_IF_WITHOUT_ELSE for the generated statement
*/
public int genStatement() {
- return switch (random.nextInt(10)) {
+ return switch (random.nextInt(12)) {
+ case 0 -> allowStructs || generateInvalid() ? genStruct() : genAssignment();
case 1 -> genBlock();
case 2 -> genIf();
- case 3 -> genWhile();
- case 4, 5 -> genDecl();
- case 6, 7, 8 -> genAssignment();
+ case 3 -> genCountedLoop();
+ case 4 -> genWhile();
+ case 5, 6 -> genDecl();
+ case 7, 8, 9 -> genAssignment();
+ case 10 -> genNullCheck();
default -> genExit();
};
}
/**
+ * Generate a new structure
+ * @return 0
+ */
+ public int genStruct() {
+ var name = getStructName();
+ var fields = new TypeStruct.Field[generateInvalid() ? 0 : random.nextInt(10)];
+ sb.append("struct ").append(name).append(" {\n");
+ indentation += INDENTATION;
+ for (int i=0; i<fields.length; i++) {
+ var fieldName = getRandomName();
+ var type = generateInvalid() ? getType() : TYPE_INT;
+ printIndentation().append(type.name).append(" ").append(fieldName).append(";\n");
+ fields[i] = new TypeStruct.Field(fieldName.toString(), type);
+ }
+ indentation -= INDENTATION;
+ printIndentation().append("}");
+ structs.add(new TypeStruct(name, fields));
+ return 0;
+ }
+
+ /**
* Generate a statement for if, else and while blocks.
* This is special since it disallows declarations and prefers to generate blocks.
* @return flags FLAG_STOP and FLAG_IF_WITHOUT_ELSE for the generated statement
*/
public int genStatementBlock() {
+ var oldAllowStructs = allowStructs;
+ allowStructs = false;
indentation += INDENTATION;
int res;
if (depth == 0) {
res = random.nextBoolean() ? genAssignment() : genExit();
} else {
depth--;
- res = switch (random.nextInt(10)) {
+ res = switch (random.nextInt(12)) {
case 1, 2, 3, 4, 5 -> {
depth++;
indentation -= INDENTATION;
@@ -244,13 +449,16 @@ public class ScriptGenerator {
yield ret;
}
case 6 -> genIf();
- case 7 -> genWhile();
- case 8 -> genAssignment();
+ case 7 -> genCountedLoop();
+ case 8 -> genWhile();
+ case 9 -> genAssignment();
+ case 10 -> genNullCheck();
default -> genExit();
};
depth++;
}
indentation -= INDENTATION;
+ allowStructs = oldAllowStructs;
return res;
}
@@ -284,18 +492,20 @@ public class ScriptGenerator {
sb.append("{}");
return 0;
}
- depth--;
- int oldCSS = currScopeStart;
+ var oldAllowStructs = allowStructs;
+ var oldCSS = currScopeStart;
+ allowStructs = false;
currScopeStart = variables.size();
+ depth--;
sb.append("{\n");
indentation += INDENTATION;
var stop = genStatements();
indentation -= INDENTATION;
printIndentation().append("}");
- while (variables.size() > currScopeStart)
- variables.removeLast();
- currScopeStart = oldCSS;
+ popVariables(currScopeStart);
depth++;
+ currScopeStart = oldCSS;
+ allowStructs = oldAllowStructs;
return stop & ~FLAG_IF_WITHOUT_ELSE;
}
@@ -305,7 +515,7 @@ public class ScriptGenerator {
*/
public int genIf() {
sb.append("if(");
- genExpression();
+ genExpression(TYPE_INT);
sb.append(") ");
var stop = genStatementBlock();
if ((stop & FLAG_IF_WITHOUT_ELSE) == 0 && random.nextInt(10) > 3) {
@@ -319,12 +529,39 @@ public class ScriptGenerator {
}
/**
+ * Generate a block with a null check
+ * if (nullable) { handle_nullable_as_non_nullable; }
+ */
+ public int genNullCheck() {
+ var v = findVisibleVariablesMatching(va->va.declared instanceof TypeNullable);
+ if (v == null) return genIf();
+ var n = (TypeNullable)v.declared;
+ boolean negate = random.nextBoolean();
+ sb.append("if(");
+ if (negate) sb.append("!");
+ sb.append(v.name).append(")");
+ if (!negate) v.type = n.base;
+ var stop = genStatementBlock();
+ v.type = n;
+ if ((stop & FLAG_IF_WITHOUT_ELSE) == 0 && random.nextInt(10) > 3) {
+ sb.append("\n");
+ printIndentation().append("else ");
+ if (negate) v.type = n.base;
+ stop &= genStatementBlock();
+ v.type = n;
+ } else {
+ stop = FLAG_IF_WITHOUT_ELSE;
+ }
+ return stop;
+ }
+
+ /**
* Generate a while loop.
* @return 0
*/
public int genWhile() {
sb.append("while(");
- genExpression();
+ genExpression(TYPE_INT);
sb.append(") ");
loopDepth++;
genStatementBlock();
@@ -333,15 +570,61 @@ public class ScriptGenerator {
}
/**
+ * Generate a counted loop of the form
+ * <code>
+ * {
+ * int varname = start_expr;
+ * while (varname < end_expr) loop_body;
+ * }
+ * </code>
+ * @return 0
+ */
+ public int genCountedLoop() {
+ if (depth == 0) return genWhile();
+ var oldCSS = currScopeStart;
+ currScopeStart = variables.size();
+ sb.append("{\n");
+ indentation += INDENTATION;
+ String name = getVarName();
+ printIndentation().append("int ").append(name).append("=");
+ genExpression(TYPE_INT);
+ sb.append(";\n");
+ addVariable(name, TYPE_INT);
+ printIndentation().append("while(").append(name).append("<");
+ genExpression(TYPE_INT);
+ sb.append(") {\n");
+ indentation += INDENTATION;
+ depth--;
+ loopDepth++;
+ printIndentation().append(name).append("=").append(name).append("+");
+ genExpression(TYPE_INT);
+ sb.append(";\n");
+ genStatements();
+ loopDepth--;
+ depth++;
+ indentation -= INDENTATION;
+ printIndentation().append("}\n");
+ indentation -= INDENTATION;
+ printIndentation().append("}");
+ popVariables(currScopeStart);
+ currScopeStart = oldCSS;
+ return 0;
+ }
+
+ /**
* Generate a declaration statement.
* @return 0
*/
public int genDecl() {
- String name = getVarName();
- sb.append("int ").append(name).append("=");
- genExpression();
+ var type = getType();
+ var name = getVarName();
+ sb.append(generateInvalid() ? getRandomName() : type.name).append(" ").append(name);
+ if (!(type instanceof TypeNullable) || random.nextBoolean()) {
+ sb.append("=");
+ genExpression(type);
+ }
sb.append(";");
- variables.add(name);
+ addVariable(name, type);
return 0;
}
@@ -350,10 +633,30 @@ public class ScriptGenerator {
* @return 0
*/
public int genAssignment() {
- if (variables.isEmpty()) return genDecl();
- genVariable();
+ Type type;
+ Type declared;
+ if (generateInvalid()) {
+ sb.append(getRandomName());
+ type = getType();
+ declared = type;
+ } else {
+ var v = findVisibleVariablesMatching(va->true);
+ if (v == null) return genDecl();
+ sb.append(v.name);
+ type = v.type;
+ declared = v.declared;
+ }
+ if (generateInvalid()) {
+ var name = getRandomName();
+ sb.append(".").append(name);
+ declared = getType();
+ } else if (type instanceof TypeStruct s && s.fields.length > 0 && random.nextBoolean()) {
+ var field = s.fields[random.nextInt(s.fields.length)];
+ sb.append(".").append(field.name);
+ declared = field.type;
+ }
sb.append("=");
- genExpression();
+ genExpression(declared);
sb.append(";");
return 0;
}
@@ -363,94 +666,127 @@ public class ScriptGenerator {
* @return FLAG_STOP
*/
public int genReturn() {
+ var type = getType();
sb.append("return ");
- genExpression();
+ genExpression(type);
sb.append(";");
return FLAG_STOP;
}
-
/**
* Generate a binary expression.
* This method does not care about operator precedence.
*/
- public void genExpression() {
- var num = randLog(10);
+ public void genExpression(Type type) {
+ if (generateInvalid()) type = getType();
+ if (type != TYPE_INT) {
+ genUnary(type);
+ return;
+ }
+ var num = randLog(MAX_BINARY_EXPRESSIONS_PER_EXPRESSION);
while(num-->0) {
- genUnary();
+ genUnary(TYPE_INT);
sb.append(BINARY_OP[random.nextInt(BINARY_OP.length)]);
}
- genUnary();
+ genUnary(TYPE_INT);
}
/**
* Generate a unary expression.
*/
- public void genUnary() {
- var num = randLog(6);
+ public void genUnary(Type type) {
+ if (generateInvalid()) type = getType();
+ if (type != TYPE_INT) {
+ genSuffix(type);
+ return;
+ }
+ var num = randLog(MAX_UNARY_EXPRESSIONS_PER_EXPRESSION);
while(num-->0) {
sb.append(UNARY_OP[random.nextInt(UNARY_OP.length)]);
}
- genPrimary();
+ genSuffix(TYPE_INT);
+ }
+
+ /**
+ * Generate
+ */
+ public void genSuffix(Type type) {
+ if (generateInvalid()) type = getType();
+ if (type == TYPE_INT && random.nextBoolean()) {
+ var t = getType();
+ if (generateInvalid()) {
+ var field = getRandomName();
+ genPrimary(t);
+ sb.append(".").append(field);
+ return;
+ } else if (t instanceof TypeStruct s && s.fields.length > 0) {
+ var field = s.fields[random.nextInt(s.fields.length)];
+ if (field.type == TYPE_INT) {
+ genPrimary(t);
+ sb.append(".").append(field.name);
+ return;
+ }
+ }
+ }
+ genPrimary(type);
}
/**
* Generate a primary expression.
*/
- public void genPrimary() {
- switch (random.nextInt(10)) {
- case 0:
- sb.append("true");
- break;
- case 1:
- sb.append("false");
- break;
- case 2:
- if (exprDepth == 0) {
- // Ensure termination of the generator.
- if (random.nextBoolean()) {
- genNumber();
- } else {
- genVariable();
- }
- } else {
- sb.append("(");
- exprDepth--;
- genExpression();
- exprDepth++;
- sb.append(")");
- }
- break;
- case 3, 4, 5, 6:
- genNumber();
- break;
- default:
- genVariable();
+ public void genPrimary(Type type) {
+ if (generateInvalid()) type = getType();
+ var rand = random.nextInt(10);
+ if (rand == 0 && exprDepth != 0) {
+ sb.append("(");
+ exprDepth--;
+ genExpression(type);
+ exprDepth++;
+ sb.append(")");
+ } else if (rand < 6) {
+ genVariable(type);
+ } else {
+ genConst(type);
}
}
/**
- * Generate a number.
+ * Generate a constant.
*/
- public void genNumber() {
- sb.append(random.nextInt(100));
+ public void genConst(Type type) {
+ if (generateInvalid()) type = getType();
+ if (type == TYPE_INT) {
+ var rand = random.nextInt(10);
+ switch (rand) {
+ case 0 -> sb.append("true");
+ case 1 -> sb.append("false");
+ default -> sb.append(random.nextInt(1<<(rand-2)));
+ }
+ } else if (type instanceof TypeNullable n) {
+ if (random.nextBoolean()) {
+ sb.append("null");
+ } else {
+ sb.append("new ").append(generateInvalid() ? getRandomName() : n.base.name);
+ }
+ } else {
+ sb.append("new ").append(generateInvalid() ? getRandomName() : type.name);
+ }
}
/**
* Generate a variable. If there are none generate a number instead.
* If the program is allowed to be invalid a random name can be generated in some cases.
*/
- public void genVariable() {
- if (!generateValid && random.nextInt(100)>97) {
+ public void genVariable(Type type) {
+ if (generateInvalid()) {
sb.append(getRandomName());
- maybeInvalid = true;
return;
}
- if (variables.isEmpty()) {
- genNumber();
- } else {
- sb.append(variables.get(random.nextInt(variables.size())));
- }
+ if (generateInvalid()) type = getType();
+ var t = type;
+ var v = findVisibleVariablesMatching(va->va.type.isa(t));
+ if (v == null) genConst(type);
+ else sb.append(v.name);
}
}