Chapter 2 (#4)

* Start on Chapter 2.

* Start on Chapter 2.

* Refactor

* Refactor

* Initial attempt at peephole opt for add operation

* cleanup unused import

* Start on graph visualizer

* Start on graph visualizer

* Rework chapter 2

Add a short discourse on the Types, and provide a Bottom type.

Make a final toString; require each Node to specify its special printing via label().

Add a recursing printer called print(); toString is used by default in the debugger and so cannot be recursive.

Make the peephole rules based on a proper Type and idealize calls.
Big comments about the Type computations.

Every node picks up a _print, compute and idealize() call.

Rename long arith ops Divide, UnaryMinus, Multiply, Subtract into shorter uniform-length names.  Cleans up the parser where he does the precedence op parsing.

Rework Parser:
- Drop Token class, its all Strings except in the one place we know a number is coming
- Embed the Lexer as a field in the Parser, instead of trying to pass it around everywhere in the Parser
- StartNode becomes a read-only global, so we don't have to pass it around everywhere in the Parser AND optimizer.
- Lexer matches on strings and returns strings.  Match and consume *at the moment* instead of carrying around a current token/string and forcing the next-token after consuming the current one.
- All parse subexpressions shrink by 1/2 after these changes.

* Initial writeup of Chapter 2

* Initial writeup of Chapter 2

* Initial writeup of Chapter 2

* Initial writeup of Chapter 2

* Remove range

* progress Chapter 2

Drop integer ranges.
Broader lattice pic.
Lots of prose changes in the readme.
Fixed title in gviz dot generation.
Fixed bug with peephole making redundant constants.

* Implement compute for all the arithmetic node types
Add a flag to switch off peephole so we can see the full graph
Add post peephole graph to writeup

* Implement compute for all the arithmetic node types
Add a flag to switch off peephole so we can see the full graph
Add post peephole graph to writeup

* Fix bad path to the svg

* Update pre-peephole diagram

* Add dead code elimination

...and a set_def to proper update graph edges.

* Update README.md

* Cleanup the GraphVisualizer a bit.
Update the graphs.
Update the chapter list as chapter 3 deleted, and chapter 4 is now chapter 3.

---------

Co-authored-by: Cliff Click <cliffc@acm.org>

1 files changed, 35 insertions, 0 deletions

diff --git a/chapter02/docs/02-lattice.gv b/chapter02/docs/02-lattice.gv
new file mode 100644
index 00000000..57f14d77
--- /dev/null
+++ b/chapter02/docs/02-lattice.gv
@@ -0,0 +1,35 @@
+digraph Lattice {
+    // Define nodes
+    node [shape=circle, style=filled, fillcolor=lightblue];
+    Top [label="⊤"];
+    Bottom [label="⊥"];
+    
+    A [label="MIN_INT"];
+    B [label="..." shape=none style=none];
+    C [label="-1"];
+    D [label="0"];
+    E [label="1"];
+    F [label="..." shape=none style=none];
+    G [label="MAX_INT"];
+
+
+    // Define edges
+    Top -> A [arrowhead=none];
+    Top -> B [arrowhead=none];
+    Top -> C [arrowhead=none];
+    Top -> D [arrowhead=none];
+    Top -> E [arrowhead=none];
+    Top -> F [arrowhead=none];
+    Top -> G [arrowhead=none];
+    A -> Bottom [arrowhead=none];
+    B -> Bottom [arrowhead=none];
+    C -> Bottom [arrowhead=none];
+    D -> Bottom [arrowhead=none];
+    E -> Bottom [arrowhead=none];
+    F -> Bottom [arrowhead=none];
+    G -> Bottom [arrowhead=none];
+
+    // Additional customization
+    {rank=same; A; B; C; D; E; F; G; }
+    {rank=same; Bottom;}
+}