From 736c658c274404084b15b450b2ab72d0e7569586 Mon Sep 17 00:00:00 2001 From: Dibyendu Majumdar Date: Fri, 3 Nov 2023 21:21:54 +0000 Subject: Backport changes in Chapter 5 to previous chapters and update Chapter5 documentation (#34) * Backport changes from chapter 5 to older chapters (#30) * Fix wrong indent * Backport to chapter 4 * Backport to chapter 3 * Backport to chapter 2 * Backport to chapter 1 * Add if statement to comment (#32) * Update visuals for chapters 1,2 & 3. Reenable drawing of edges from constants to Start for these chapters. * Update visuals for chapters 4. Revise text to explain the labeling of edges in graphs and that we omit edge from Constant to Start nodes from chapter 4. * Add code snippets for if statement parsing and the duplication and merging of ScopeNodes. Explain how scopeNodes are duplicated and merged. * Add constant check to minus node (#31) * Fix closing root block with } (#33) * Backport fix closing root block with } to chapter 4 and 3 (#35) * Show use-def edge from Phi to Region as dotted edge. Add example of Phi peephole. Update visuals. Add more examples. * Fix visuals in chapter 1 and README in chapter 4. * Remove subheading * Adjust spaces --------- Co-authored-by: XmiliaH <45106915+XmiliaH@users.noreply.github.com> --- .../com/seaofnodes/simple/GraphVisualizer.java | 76 +++++++++------ .../main/java/com/seaofnodes/simple/Parser.java | 69 ++++++++------ .../java/com/seaofnodes/simple/node/AddNode.java | 20 ++-- .../com/seaofnodes/simple/node/ConstantNode.java | 15 +-- .../java/com/seaofnodes/simple/node/Control.java | 9 -- .../java/com/seaofnodes/simple/node/DivNode.java | 25 +++-- .../java/com/seaofnodes/simple/node/MinusNode.java | 15 ++- .../java/com/seaofnodes/simple/node/MulNode.java | 24 ++--- .../main/java/com/seaofnodes/simple/node/Node.java | 106 ++++++++++++--------- .../com/seaofnodes/simple/node/ReturnNode.java | 9 +- .../java/com/seaofnodes/simple/node/StartNode.java | 16 ++-- .../java/com/seaofnodes/simple/node/SubNode.java | 20 ++-- .../java/com/seaofnodes/simple/type/TypeBot.java | 4 +- .../com/seaofnodes/simple/type/TypeInteger.java | 4 +- 14 files changed, 224 insertions(+), 188 deletions(-) delete mode 100644 chapter02/src/main/java/com/seaofnodes/simple/node/Control.java (limited to 'chapter02/src/main/java/com') diff --git a/chapter02/src/main/java/com/seaofnodes/simple/GraphVisualizer.java b/chapter02/src/main/java/com/seaofnodes/simple/GraphVisualizer.java index 1af19d80..df128674 100644 --- a/chapter02/src/main/java/com/seaofnodes/simple/GraphVisualizer.java +++ b/chapter02/src/main/java/com/seaofnodes/simple/GraphVisualizer.java @@ -1,9 +1,6 @@ package com.seaofnodes.simple; -import com.seaofnodes.simple.node.ConstantNode; -import com.seaofnodes.simple.node.Control; -import com.seaofnodes.simple.node.Node; -import com.seaofnodes.simple.node.StartNode; +import com.seaofnodes.simple.node.*; import java.util.*; @@ -21,7 +18,10 @@ public class GraphVisualizer { Collection all = findAll(parser); StringBuilder sb = new StringBuilder(); sb.append("digraph chapter02 {\n"); - + sb.append("/*\n"); + sb.append(parser.src()); + sb.append("\n*/\n"); + // To keep the Scopes below the graph and pointing up into the graph we // need to group the Nodes in a subgraph cluster, and the scopes into a // different subgraph cluster. THEN we can draw edges between the @@ -29,12 +29,19 @@ public class GraphVisualizer { // still making the subgraphs DOT gets confused. sb.append("\trankdir=BT;\n"); // Force Nodes before Scopes + // Preserve node input order + sb.append("\tordering=\"in\";\n"); + + // Merge multiple edges hitting the same node. Makes common shared + // nodes much prettier to look at. + sb.append("\tconcentrate=\"true\";\n"); + // Just the Nodes first, in a cluster no edges nodes(sb, all); // Walk the Node edges nodeEdges(sb, all); - + sb.append("}\n"); return sb.toString(); } @@ -43,13 +50,14 @@ public class GraphVisualizer { private void nodes(StringBuilder sb, Collection all) { // Just the Nodes first, in a cluster no edges sb.append("\tsubgraph cluster_Nodes {\n"); // Magic "cluster_" in the subgraph name - for (Node n : all) { + for( Node n : all ) { sb.append("\t\t").append(n.uniqueName()).append(" [ "); + String lab = n.glabel(); // control nodes have box shape // other nodes are ellipses, i.e. default shape - if (n instanceof Control) + if( n.isCFG() ) sb.append("shape=box style=filled fillcolor=yellow "); - sb.append("label=\"").append(n.label()).append("\" "); + sb.append("label=\"").append(lab).append("\" "); sb.append("];\n"); } sb.append("\t}\n"); // End Node cluster @@ -58,25 +66,32 @@ public class GraphVisualizer { // Walk the node edges private void nodeEdges(StringBuilder sb, Collection all) { - for( Node n : all ) - for( Node out : n._inputs ) - if( out != null ) { - sb.append('\t').append(n.uniqueName()).append(" -> ").append(out.uniqueName()); - // Control edges are colored red - if( n instanceof ConstantNode && out instanceof StartNode ) - sb.append(" [style=dotted]"); - else if( n instanceof Control && out instanceof Control ) - sb.append(" [color=red]"); - sb.append(";\n"); + // All them edge labels + sb.append("\tedge [ fontname=Helvetica, fontsize=8 ];\n"); + for( Node n : all ) { + // In this chapter we do display the Constant->Start edge; + int i=0; + for( Node def : n._inputs ) { + if( def != null ) { + // Most edges land here use->def + sb.append('\t').append(n.uniqueName()).append(" -> "); + sb.append(def.uniqueName()); + // Number edges, so we can see how they track + sb.append("[taillabel=").append(i); + if( n instanceof ConstantNode && def instanceof StartNode ) + sb.append(" style=dotted"); + // control edges are colored red + else if( def.isCFG() ) + sb.append(" color=red"); + sb.append("];\n"); + } + i++; + } } } - + /** - * Walks the whole graph, starting from Start. - * Since Start is the input to all constants - we look at the outputs for - * Start, but for then subsequently we look at the inputs of each node. - * During graph construction not all nodes are reachable this way, so we - * also scan the symbol tables. + * Finds all nodes in the graph. */ private Collection findAll(Parser parser) { final StartNode start = Parser.START; @@ -91,9 +106,12 @@ public class GraphVisualizer { */ private void walk(HashMap all, Node n) { if (all.get(n._nid) != null) return; // Been there, done that - all.put(n._nid, n); - for (Node c : n._inputs) - if (c != null) - walk(all, c); + all.put(n._nid, n); + for (Node c : n._inputs) + if (c != null) + walk(all, c); + for (Node c : n._outputs) + if (c != null) + walk(all, c); } } diff --git a/chapter02/src/main/java/com/seaofnodes/simple/Parser.java b/chapter02/src/main/java/com/seaofnodes/simple/Parser.java index 3ca13c3f..5422ea66 100644 --- a/chapter02/src/main/java/com/seaofnodes/simple/Parser.java +++ b/chapter02/src/main/java/com/seaofnodes/simple/Parser.java @@ -21,29 +21,34 @@ public class Parser { */ public static StartNode START; + // The Lexer. Thin wrapper over a byte[] buffer with a cursor. private final Lexer _lexer; - public Parser( String source ) { + + public Parser(String source) { _lexer = new Lexer(source); Node.reset(); START = new StartNode(); } + String src() { return new String( _lexer._input ); } + public ReturnNode parse() { require("return"); - return parseReturn(); + return (ReturnNode) parseReturn(); } /** - * Parses returnStatement; "return" already parsed + * Parses a return statement; "return" already parsed. * * 
      *     'return' expr ;
      *
+ * @return an expression {@link Node}, never {@code null} */ - private ReturnNode parseReturn() { - var expr = require(parseExpression(),";"); - return new ReturnNode(START, expr); + private Node parseReturn() { + var expr = require(parseExpression(), ";"); + return new ReturnNode(START, expr).peephole(); } /** @@ -52,6 +57,7 @@ public class Parser { * 
      *     expr : additiveExpr
      *
+ * @return an expression {@link Node}, never {@code null} */ private Node parseExpression() { return parseAddition(); } @@ -61,11 +67,12 @@ public class Parser { * 
      *     additiveExpr : multiplicativeExpr (('+' | '-') multiplicativeExpr)*
      *
+ * @return an add expression {@link Node}, never {@code null} */ private Node parseAddition() { var lhs = parseMultiplication(); - if( match("+") ) return new AddNode(lhs, parseAddition()).peephole(); - if( match("-") ) return new SubNode(lhs, parseAddition()).peephole(); + if (match("+")) return new AddNode(lhs, parseAddition()).peephole(); + if (match("-")) return new SubNode(lhs, parseAddition()).peephole(); return lhs; } @@ -75,11 +82,12 @@ public class Parser { * 
      *     multiplicativeExpr : unaryExpr (('*' | '/') unaryExpr)*
      *
+ * @return a multiply expression {@link Node}, never {@code null} */ private Node parseMultiplication() { var lhs = parseUnary(); - if( match("*") ) return new MulNode(lhs, parseMultiplication()).peephole(); - if( match("/") ) return new DivNode(lhs, parseMultiplication()).peephole(); + if (match("*")) return new MulNode(lhs, parseMultiplication()).peephole(); + if (match("/")) return new DivNode(lhs, parseMultiplication()).peephole(); return lhs; } @@ -89,9 +97,10 @@ public class Parser { * 
      *     unaryExpr : ('-') unaryExpr | primaryExpr
      *
+ * @return a unary expression {@link Node}, never {@code null} */ private Node parseUnary() { - if( match("-") ) return new MinusNode(parseUnary()).peephole(); + if (match("-")) return new MinusNode(parseUnary()).peephole(); return parsePrimary(); } @@ -99,12 +108,13 @@ public class Parser { * Parse a primary expression: * * 
-     *     primaryExpr : integerLiteral
+     *     primaryExpr : integerLiteral | Identifier | '(' expression ')'
      *
+ * @return a primary {@link Node}, never {@code null} */ private Node parsePrimary() { if( _lexer.isNumber() ) return parseIntegerLiteral(); - if( match("(") ) return require(parseExpression(),")"); + if( match("(") ) return require(parseExpression(), ")"); throw errorSyntax("integer literal"); } @@ -116,7 +126,7 @@ public class Parser { * */ private ConstantNode parseIntegerLiteral() { - return (ConstantNode)new ConstantNode(_lexer.parseNumber()).peephole(); + return (ConstantNode) new ConstantNode(_lexer.parseNumber()).peephole(); } ////////////////////////////////// @@ -126,7 +136,7 @@ public class Parser { private boolean match(String syntax) { return _lexer.match(syntax); } // Require an exact match - private void require(String syntax) { require(null,syntax); } + private void require(String syntax) { require(null, syntax); } private Node require(Node n, String syntax) { if (match(syntax)) return n; throw errorSyntax(syntax); @@ -135,7 +145,7 @@ public class Parser { RuntimeException errorSyntax(String syntax) { return error("Syntax error, expected " + syntax + ": " + _lexer.getAnyNextToken()); } - + static RuntimeException error(String errorMessage) { return new RuntimeException(errorMessage); } @@ -167,9 +177,9 @@ public class Parser { // Very handy in the debugger, shows the unparsed program @Override public String toString() { - return new String(_input,_position,_input.length-_position); + return new String(_input, _position, _input.length - _position); } - + // True if at EOF private boolean isEOF() { return _position >= _input.length; @@ -203,12 +213,12 @@ public class Parser { // Return true, if we find "syntax" after skipping white space; also // then advance the cursor past syntax. // Return false otherwise, and do not advance the cursor. - boolean match( String syntax ) { + boolean match(String syntax) { skipWhiteSpace(); int len = syntax.length(); - if( _position + len > _input.length ) return false; - for( int i = 0; i < len; i++ ) - if( (char)_input[_position + i] != syntax.charAt(i) ) + if (_position + len > _input.length) return false; + for (int i = 0; i < len; i++) + if ((char) _input[_position + i] != syntax.charAt(i)) return false; _position += len; return true; @@ -216,14 +226,14 @@ public class Parser { // Used for errors String getAnyNextToken() { - if( isEOF() ) return ""; - if( isIdStart(peek()) ) return parseId(); - if( isPunctuation(peek()) ) return parsePunctuation(); + if (isEOF()) return ""; + if (isIdStart(peek())) return parseId(); + if (isPunctuation(peek())) return parsePunctuation(); return String.valueOf(peek()); } - boolean isNumber() { return isNumber(peek()); } - boolean isNumber(char ch) { return Character.isDigit(ch); } + boolean isNumber() {return isNumber(peek());} + boolean isNumber(char ch) {return Character.isDigit(ch);} private Type parseNumber() { int start = _position; @@ -231,7 +241,7 @@ public class Parser { String snum = new String(_input, start, --_position - start); if (snum.length() > 1 && snum.charAt(0) == '0') throw error("Syntax error: integer values cannot start with '0'"); - return new TypeInteger(Long.parseLong(snum)); + return TypeInteger.constant(Long.parseLong(snum)); } // First letter of an identifier @@ -257,8 +267,7 @@ public class Parser { private String parsePunctuation() { int start = _position; - if (isPunctuation(nextChar())) ; - return new String(_input, start, --_position - start); + return new String(_input, start, 1); } } diff --git a/chapter02/src/main/java/com/seaofnodes/simple/node/AddNode.java b/chapter02/src/main/java/com/seaofnodes/simple/node/AddNode.java index 015779dc..6784ad60 100644 --- a/chapter02/src/main/java/com/seaofnodes/simple/node/AddNode.java +++ b/chapter02/src/main/java/com/seaofnodes/simple/node/AddNode.java @@ -3,17 +3,16 @@ package com.seaofnodes.simple.node; import com.seaofnodes.simple.type.*; public class AddNode extends Node { - public AddNode(Node lhs, Node rhs) { - super(null, lhs, rhs); - } + public AddNode(Node lhs, Node rhs) { super(null, lhs, rhs); } - @Override - public String label() { return "Add"; } + @Override public String label() { return "Add"; } + + @Override public String glabel() { return "+"; } @Override - StringBuilder _print(StringBuilder sb) { - in(1)._print(sb.append("(")); - in(2)._print(sb.append("+")); + StringBuilder _print1(StringBuilder sb) { + in(1)._print0(sb.append("(")); + in(2)._print0(sb.append("+")); return sb.append(")"); } @@ -21,8 +20,9 @@ public class AddNode extends Node { @Override public Type compute() { if( in(1)._type instanceof TypeInteger i0 && - in(2)._type instanceof TypeInteger i1 ) - return new TypeInteger(i0._con + i1._con); + in(2)._type instanceof TypeInteger i1 ) { + return TypeInteger.constant(i0.value()+i1.value()); + } return TypeBot.BOTTOM; } diff --git a/chapter02/src/main/java/com/seaofnodes/simple/node/ConstantNode.java b/chapter02/src/main/java/com/seaofnodes/simple/node/ConstantNode.java index 99ccf4b5..ec85bf1f 100644 --- a/chapter02/src/main/java/com/seaofnodes/simple/node/ConstantNode.java +++ b/chapter02/src/main/java/com/seaofnodes/simple/node/ConstantNode.java @@ -16,22 +16,25 @@ import com.seaofnodes.simple.type.Type; * The Constant's value is the value stored in it. */ public class ConstantNode extends Node { - + Type _con; public ConstantNode( Type type ) { super(Parser.START); - _type = type; + _con = type; } @Override - public String label() { return "Con" + _type; } + public String label() { return "#"+_con; } + + @Override + public String uniqueName() { return "Con_" + _nid; } @Override - StringBuilder _print(StringBuilder sb) { - return _type._print(sb); + StringBuilder _print1(StringBuilder sb) { + return _con._print(sb); } @Override - public Type compute() { return _type; } + public Type compute() { return _con; } @Override public Node idealize() { return null; } diff --git a/chapter02/src/main/java/com/seaofnodes/simple/node/Control.java b/chapter02/src/main/java/com/seaofnodes/simple/node/Control.java deleted file mode 100644 index 48cf2b7a..00000000 --- a/chapter02/src/main/java/com/seaofnodes/simple/node/Control.java +++ /dev/null @@ -1,9 +0,0 @@ -package com.seaofnodes.simple.node; - - -/** - * Control interface is a marker interface to be implemented - * by Control nodes. - */ -public interface Control { -} diff --git a/chapter02/src/main/java/com/seaofnodes/simple/node/DivNode.java b/chapter02/src/main/java/com/seaofnodes/simple/node/DivNode.java index 0056c42d..ca7df79c 100644 --- a/chapter02/src/main/java/com/seaofnodes/simple/node/DivNode.java +++ b/chapter02/src/main/java/com/seaofnodes/simple/node/DivNode.java @@ -5,17 +5,16 @@ import com.seaofnodes.simple.type.TypeBot; import com.seaofnodes.simple.type.TypeInteger; public class DivNode extends Node { - public DivNode(Node lhs, Node rhs) { - super(null, lhs, rhs); - } + public DivNode(Node lhs, Node rhs) { super(null, lhs, rhs); } + + @Override public String label() { return "Div"; } + + @Override public String glabel() { return "//"; } @Override - public String label() { return "Div"; } - - @Override - StringBuilder _print(StringBuilder sb) { - in(1)._print(sb.append("(")); - in(2)._print(sb.append("/")); + StringBuilder _print1(StringBuilder sb) { + in(1)._print0(sb.append("(")); + in(2)._print0(sb.append("/")); return sb.append(")"); } @@ -23,11 +22,9 @@ public class DivNode extends Node { public Type compute() { if (in(1)._type instanceof TypeInteger i0 && in(2)._type instanceof TypeInteger i1) { - if (i0.isConstant() && i1.isConstant()) - return i1._con == 0 - ? TypeInteger.ZERO - : new TypeInteger(i0._con/i1._con); - return new TypeInteger(i0._con / i1._con); + return i1.value() == 0 + ? TypeInteger.ZERO + : TypeInteger.constant(i0.value()/i1.value()); } return TypeBot.BOTTOM; } diff --git a/chapter02/src/main/java/com/seaofnodes/simple/node/MinusNode.java b/chapter02/src/main/java/com/seaofnodes/simple/node/MinusNode.java index 7fab83b0..834f4c11 100644 --- a/chapter02/src/main/java/com/seaofnodes/simple/node/MinusNode.java +++ b/chapter02/src/main/java/com/seaofnodes/simple/node/MinusNode.java @@ -5,23 +5,22 @@ import com.seaofnodes.simple.type.TypeBot; import com.seaofnodes.simple.type.TypeInteger; public class MinusNode extends Node { - public MinusNode(Node in) { - super(null, in); - } + public MinusNode(Node in) { super(null, in); } - @Override - public String label() { return "Minus"; } + @Override public String label() { return "Minus"; } + + @Override public String glabel() { return "-"; } @Override - StringBuilder _print(StringBuilder sb) { - in(1)._print(sb.append("(-")); + StringBuilder _print1(StringBuilder sb) { + in(1)._print0(sb.append("(-")); return sb.append(")"); } @Override public Type compute() { if (in(1)._type instanceof TypeInteger i0) - return new TypeInteger(-i0._con); + return TypeInteger.constant(-i0.value()); return TypeBot.BOTTOM; } diff --git a/chapter02/src/main/java/com/seaofnodes/simple/node/MulNode.java b/chapter02/src/main/java/com/seaofnodes/simple/node/MulNode.java index e1a26858..0fa54966 100644 --- a/chapter02/src/main/java/com/seaofnodes/simple/node/MulNode.java +++ b/chapter02/src/main/java/com/seaofnodes/simple/node/MulNode.java @@ -5,25 +5,25 @@ import com.seaofnodes.simple.type.TypeBot; import com.seaofnodes.simple.type.TypeInteger; public class MulNode extends Node { - public MulNode(Node lhs, Node rhs) { - super(null, lhs, rhs); - } - - @Override - public String label() { return "Mul"; } + public MulNode(Node lhs, Node rhs) { super(null, lhs, rhs); } + + @Override public String label() { return "Mul"; } + @Override public String glabel() { return "*"; } + @Override - StringBuilder _print(StringBuilder sb) { - in(1)._print(sb.append("(")); - in(2)._print(sb.append("*")); + StringBuilder _print1(StringBuilder sb) { + in(1)._print0(sb.append("(")); + in(2)._print0(sb.append("*")); return sb.append(")"); } - + @Override public Type compute() { if (in(1)._type instanceof TypeInteger i0 && - in(2)._type instanceof TypeInteger i1) - return new TypeInteger(i0._con * i1._con); + in(2)._type instanceof TypeInteger i1) { + return TypeInteger.constant(i0.value()*i1.value()); + } return TypeBot.BOTTOM; } diff --git a/chapter02/src/main/java/com/seaofnodes/simple/node/Node.java b/chapter02/src/main/java/com/seaofnodes/simple/node/Node.java index 7c39083e..dbef984e 100644 --- a/chapter02/src/main/java/com/seaofnodes/simple/node/Node.java +++ b/chapter02/src/main/java/com/seaofnodes/simple/node/Node.java @@ -2,8 +2,7 @@ package com.seaofnodes.simple.node; import com.seaofnodes.simple.type.Type; -import java.util.ArrayList; -import java.util.Collections; +import java.util.*; /** * All Nodes in the Sea of Nodes IR inherit from the Node class. @@ -24,8 +23,7 @@ public abstract class Node { *

* Generally fixed length, ordered, nulls allowed, no unused trailing space. * Ordering is required because e.g. "a/b" is different from "b/a". - * The first input (offset 0) is often a Control node. - * @see Control + * The first input (offset 0) is often a {@link #isCFG} node. */ public final ArrayList _inputs; @@ -40,6 +38,13 @@ public abstract class Node { */ public final ArrayList _outputs; + + /** + * Current computed type for this Node. This value changes as the graph + * changes and more knowledge is gained about the program. + */ + public Type _type; + /** * A private Global Static mutable counter, for unique node id generation. * To make the compiler multi-threaded, this field will have to move into a TLS. @@ -47,7 +52,7 @@ public abstract class Node { * */ private static int UNIQUE_ID = 1; - protected Node(Node ...inputs) { + protected Node(Node... inputs) { _nid = UNIQUE_ID++; // allocate unique dense ID _inputs = new ArrayList<>(); Collections.addAll(_inputs,inputs); @@ -55,26 +60,39 @@ public abstract class Node { for( Node n : _inputs ) if( n != null ) n._outputs.add( this ); - // Do an initial type computation - _type = compute(); } + // Easy reading label for debugger, e.g. "Add" or "Region" or "EQ" public abstract String label(); + // Unique label for graph visualization, e.g. "Add12" or "Region30" or "EQ99" public String uniqueName() { return label() + _nid; } + // Graphical label, e.g. "+" or "Region" or "==" + public String glabel() { return label(); } + @Override public final String toString() { // TODO: This needs a lot of work - return uniqueName(); + return print(); } // This is a *deep* print. This version will fail on cycles, which we will - // correct later when we can parse programs with loops. + // correct later when we can parse programs with loops. We print with a + // tik-tok style; the common _print0 calls the per-Node _print1, which + // calls back to _print0; public final String print() { - return _print(new StringBuilder()).toString(); + return _print0(new StringBuilder()).toString(); + } + // This is the common print: check for DEAD and print "DEAD" else call the + // per-Node print1. + final StringBuilder _print0(StringBuilder sb) { + return isDead() + ? sb.append(uniqueName()).append(":DEAD") + : _print1(sb); } - abstract StringBuilder _print(StringBuilder sb); + // Every Node implements this. + abstract StringBuilder _print1(StringBuilder sb); /** @@ -86,25 +104,21 @@ public abstract class Node { public int nIns() { return _inputs.size(); } - /** - * Gets the ith output node - * @param i Offset of the output node - * @return Output node (not null) - */ - public Node out(int i) { return _outputs.get(i); } - public int nOuts() { return _outputs.size(); } + public boolean isUnused() { return nOuts() == 0; } + + public boolean isCFG() { return false; } + /** * We allow disabling peephole opt so that we can observe the * full graph, vs the optimized graph. */ public static boolean _disablePeephole = false; - /** * Try to peephole at this node and return a better replacement Node if - * possible. We check and replace: + * possible. We compute a {@link Type} and then check and replace: *

    *
  • if the Type {@link Type#isConstant}, we replace with a {@link ConstantNode}
    • *
  • in a future chapter we will look for a @@ -114,36 +128,27 @@ public abstract class Node { *
*/ public final Node peephole( ) { + // Compute initial or improved Type + Type type = _type = compute(); + if (_disablePeephole) return this; // Peephole optimizations turned off // Replace constant computations from non-constants with a constant node - Type type = compute(); if (!(this instanceof ConstantNode) && type.isConstant()) { kill(); // Kill `this` because replacing with a Constant - return new ConstantNode(type); + return new ConstantNode(type).peephole(); } // Future chapter: Global Value Numbering goes here - // Ask each node for a replacement + // Ask each node for a better replacement Node n = idealize(); if( n != null ) return n; return this; // No progress } - /** - * Kill a Node with no uses, by setting all of its defs - * to null. This may recursively kill more Nodes and is basically dead - * code elimination. This function is co-recursive with {@link #set_def}. - */ - void kill( ) { - assert nOuts()==0; // Has no uses, so it is dead - for( int i=0; idef into a Node. Keeps the edges correct, by removing * the corresponding use->def edge. This may make the original @@ -151,10 +156,11 @@ public abstract class Node { * * @param idx which def to set * @param new_def the new definition + * @return this for flow coding */ - void set_def(int idx, Node new_def ) { + Node set_def(int idx, Node new_def ) { Node old_def = in(idx); - if( old_def == new_def ) return; // No change + if( old_def == new_def ) return this; // No change // If new def is not null, add the corresponding def->use edge // This needs to happen before removing the old node's def->use edge as // the new_def might get killed if the old node kills it recursively. @@ -174,15 +180,26 @@ public abstract class Node { } // Set the new_def over the old (killed) edge _inputs.set(idx,new_def); + // Return self for easy flow-coding + return this; } - - /** - * Current computed type for this Node. This value changes as the graph - * changes and more knowledge is gained about the program. + * Kill a Node with no uses, by setting all of its defs + * to null. This may recursively kill more Nodes and is basically dead + * code elimination. This function is co-recursive with {@link #set_def}. */ - public Type _type; - + public void kill( ) { + assert isUnused(); // Has no uses, so it is dead + for( int i=0; iMonotonic @@ -208,9 +225,4 @@ public abstract class Node { * Node unique id generator, and is done as part of making a new Parser. */ public static void reset() { UNIQUE_ID = 1; } - - /* - * hashCode and equals implementation to be added in later chapter. - */ - } diff --git a/chapter02/src/main/java/com/seaofnodes/simple/node/ReturnNode.java b/chapter02/src/main/java/com/seaofnodes/simple/node/ReturnNode.java index c188ca79..18f5eed9 100644 --- a/chapter02/src/main/java/com/seaofnodes/simple/node/ReturnNode.java +++ b/chapter02/src/main/java/com/seaofnodes/simple/node/ReturnNode.java @@ -1,6 +1,6 @@ package com.seaofnodes.simple.node; -import com.seaofnodes.simple.type.TypeBot; +import com.seaofnodes.simple.type.*; /** * The Return node has two inputs. The first input is a control node and the @@ -11,7 +11,7 @@ import com.seaofnodes.simple.type.TypeBot; *

* The Return's output is the value from the data node. */ -public class ReturnNode extends Node implements Control { +public class ReturnNode extends Node { public ReturnNode(Node ctrl, Node data) { super(ctrl, data); @@ -24,10 +24,11 @@ public class ReturnNode extends Node implements Control { public String label() { return "Return"; } @Override - StringBuilder _print(StringBuilder sb) { - return expr()._print(sb.append("return ")).append(";"); + StringBuilder _print1(StringBuilder sb) { + return expr()._print0(sb.append("return ")).append(";"); } + @Override public boolean isCFG() { return true; } @Override public TypeBot compute() { diff --git a/chapter02/src/main/java/com/seaofnodes/simple/node/StartNode.java b/chapter02/src/main/java/com/seaofnodes/simple/node/StartNode.java index 8d8031bb..08b8333a 100644 --- a/chapter02/src/main/java/com/seaofnodes/simple/node/StartNode.java +++ b/chapter02/src/main/java/com/seaofnodes/simple/node/StartNode.java @@ -3,11 +3,13 @@ package com.seaofnodes.simple.node; import com.seaofnodes.simple.type.TypeBot; /** - * 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. 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. */ -public class StartNode extends Node implements Control { +public class StartNode extends Node { public StartNode(/*arguments go here*/) { super(); @@ -17,10 +19,12 @@ public class StartNode extends Node implements Control { public String label() { return "Start"; } @Override - StringBuilder _print(StringBuilder sb) { + StringBuilder _print1(StringBuilder sb) { return sb.append(label()); } - + + @Override public boolean isCFG() { return true; } + @Override public TypeBot compute() { return TypeBot.BOTTOM; diff --git a/chapter02/src/main/java/com/seaofnodes/simple/node/SubNode.java b/chapter02/src/main/java/com/seaofnodes/simple/node/SubNode.java index 2d7db8d3..71d70fa6 100644 --- a/chapter02/src/main/java/com/seaofnodes/simple/node/SubNode.java +++ b/chapter02/src/main/java/com/seaofnodes/simple/node/SubNode.java @@ -5,25 +5,25 @@ import com.seaofnodes.simple.type.TypeBot; import com.seaofnodes.simple.type.TypeInteger; public class SubNode extends Node { - public SubNode(Node lhs, Node rhs) { - super(null, lhs, rhs); - } + public SubNode(Node lhs, Node rhs) { super(null, lhs, rhs); } - @Override - public String label() { return "Sub"; } + @Override public String label() { return "Sub"; } + + @Override public String glabel() { return "-"; } @Override - StringBuilder _print(StringBuilder sb) { - in(1)._print(sb.append("(")); - in(2)._print(sb.append("-")); + StringBuilder _print1(StringBuilder sb) { + in(1)._print0(sb.append("(")); + in(2)._print0(sb.append("-")); return sb.append(")"); } @Override public Type compute() { if (in(1)._type instanceof TypeInteger i0 && - in(2)._type instanceof TypeInteger i1) - return new TypeInteger(i0._con - i1._con); + in(2)._type instanceof TypeInteger i1) { + return TypeInteger.constant(i0.value()-i1.value()); + } return TypeBot.BOTTOM; } diff --git a/chapter02/src/main/java/com/seaofnodes/simple/type/TypeBot.java b/chapter02/src/main/java/com/seaofnodes/simple/type/TypeBot.java index 5284884a..bc191241 100644 --- a/chapter02/src/main/java/com/seaofnodes/simple/type/TypeBot.java +++ b/chapter02/src/main/java/com/seaofnodes/simple/type/TypeBot.java @@ -8,7 +8,7 @@ public class TypeBot extends Type { @Override public String toString() { return "Bottom"; } - - @Override + + @Override public StringBuilder _print(StringBuilder sb) { return sb.append(toString()); } } diff --git a/chapter02/src/main/java/com/seaofnodes/simple/type/TypeInteger.java b/chapter02/src/main/java/com/seaofnodes/simple/type/TypeInteger.java index 06cac15e..ff6e865b 100644 --- a/chapter02/src/main/java/com/seaofnodes/simple/type/TypeInteger.java +++ b/chapter02/src/main/java/com/seaofnodes/simple/type/TypeInteger.java @@ -14,6 +14,8 @@ public class TypeInteger extends Type { public TypeInteger(long con) { _con = con; } + public static TypeInteger constant(long con) { return new TypeInteger(con); } + @Override public String toString() { return _print(new StringBuilder()).toString(); @@ -25,7 +27,7 @@ public class TypeInteger extends Type { @Override public boolean isConstant() { return true; } - public long getConstant() { return _con; } + public long value() { return _con; } @Override public boolean equals( Object o ) { -- cgit v1.2.3