Add basic block CFG visualization

- Generate CFG from linear IR blocks - Insert block labels for visualization - Override BasicBlock's compareTo for deterministic order - Render sample CFG in README
whtoo · Nov 19, 2023 · 56a31f6 · 56a31f6
1 parent ad54724
commit 56a31f6
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Showing 11 changed files with 122 additions and 20 deletions.
diff --git a/ep20/README.md b/ep20/README.md
@@ -30,4 +30,11 @@ graph LR
 ### 线性化IR
 我们的IR本质上是tree模式的，这样一来我们的线性化实际上延迟到了指令生成时。
 但是，这样一来我们就无法进行活性分析和很多与TAC表示相关的分析（或者是我没找到
-直接对栈代码做分析的例子）。因此，我要对ep20的输出code过程进行线性改造。
+直接对栈代码做分析的例子）。因此，我要对ep20的输出code过程进行线性改造。
+
+### CFG
+
+```mermaid
+graph TD;
+    L0["iconst 0;istore 0;;iconst 7;igt"]
+```
diff --git a/ep20/src/main/java/org/teachfx/antlr4/ep20/Compiler.java b/ep20/src/main/java/org/teachfx/antlr4/ep20/Compiler.java
@@ -12,7 +12,7 @@
 import org.teachfx.antlr4.ep20.parser.CymbolLexer;
 import org.teachfx.antlr4.ep20.parser.CymbolParser;
 import org.teachfx.antlr4.ep20.pass.ast.CymbolASTBuilder;
-//import org.teachfx.antlr4.ep20.pass.ir.CymbolIRBuilder;
+
 import org.teachfx.antlr4.ep20.pass.codegen.CymbolAssembler;
 import org.teachfx.antlr4.ep20.pass.ir.CymbolIRBuilder;
 import org.teachfx.antlr4.ep20.pass.symtab.LocalDefine;
@@ -49,11 +49,13 @@ public static void main(String[] args) throws IOException {
         var irBuilder = new CymbolIRBuilder();
 
         astRoot.accept(irBuilder);
-        // printIRTree(irBuilder.prog.linearInstrs());
+
+        var cfg = irBuilder.getCFG();
+        logger.info("CFG:\n" + cfg);
 
         var assembler = new CymbolAssembler();
         irBuilder.prog.accept(assembler);
-        saveToEp18Res(assembler.getAsmInfo());
+//        saveToEp18Res(assembler.getAsmInfo());
         logger.info("\n%s".formatted(assembler.getAsmInfo()));
     }
 

diff --git a/ep20/src/main/java/org/teachfx/antlr4/ep20/ir/Prog.java b/ep20/src/main/java/org/teachfx/antlr4/ep20/ir/Prog.java
@@ -37,9 +37,6 @@ public void addBlock(LinearIRBlock linearIRBlock) {
     private void linearInstrsImpl(@NotNull LinearIRBlock linearIRBlock) {
         // Add all instr from non-empty block
         if (!linearIRBlock.getStmts().isEmpty()) {
-            if (!linearIRBlock.getJmpRefMap().isEmpty()){
-                instrs.add(linearIRBlock.getLabel());
-            }
             instrs.addAll(linearIRBlock.getStmts());
         } else {
             // Drop empty block

diff --git a/ep20/src/main/java/org/teachfx/antlr4/ep20/pass/cfg/BasicBlock.java b/ep20/src/main/java/org/teachfx/antlr4/ep20/pass/cfg/BasicBlock.java
@@ -13,7 +13,13 @@
 import java.util.Optional;
 import java.util.Set;
 
-public class BasicBlock<I extends IRNode> implements Iterable<Loc<I>> {
+public class BasicBlock<I extends IRNode> implements Comparable<BasicBlock<I>>, Iterable<Loc<I>> {
+
+    @Override
+    public int compareTo(@NotNull BasicBlock<I> o) {
+        return this.id - o.id;
+    }
+
 
     // Generate codes
     public List<Loc<I>> codes;

diff --git a/ep20/src/main/java/org/teachfx/antlr4/ep20/pass/cfg/CFG.java b/ep20/src/main/java/org/teachfx/antlr4/ep20/pass/cfg/CFG.java
@@ -5,6 +5,7 @@
 import org.teachfx.antlr4.ep20.ir.IRNode;
 
 import java.util.*;
+import java.util.LinkedList;
 
 public class CFG<I extends IRNode> implements Iterable<BasicBlock<I>> {
     public final List<BasicBlock<I>> nodes;
@@ -15,7 +16,7 @@ public class CFG<I extends IRNode> implements Iterable<BasicBlock<I>> {
 
     public CFG(List<BasicBlock<I>> nodes, List<Pair<Integer, Integer>> edges) {
         // Generate init
-        this.nodes = nodes;
+        this.nodes = new LinkedList<>(nodes); ///.stream().sorted(Comparator.comparingInt(BasicBlock::getId)).toList();
         this.edges = edges;
 
         links = new ArrayList<>();
@@ -57,4 +58,12 @@ public int getOutDegree(int id) {
     public Iterator<BasicBlock<I>> iterator() {
         return nodes.iterator();
     }
+
+
+    @Override
+    public String toString() {
+        var graphRenderBuffer = new StringBuffer();
+
+        return graphRenderBuffer.toString();
+    }
 }
diff --git a/ep20/src/main/java/org/teachfx/antlr4/ep20/pass/cfg/CFGBuilder.java b/ep20/src/main/java/org/teachfx/antlr4/ep20/pass/cfg/CFGBuilder.java
@@ -1,11 +1,34 @@
 package org.teachfx.antlr4.ep20.pass.cfg;
 
+import org.apache.commons.lang3.tuple.Pair;
 import org.teachfx.antlr4.ep20.ir.IRNode;
 
+import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 
-public class CFGBuilder<I extends IRNode> {
-    public CFGBuilder(BasicBlock<IRNode> startNode){
+public class CFGBuilder {
+    private CFG<IRNode> cfg;
+    private List<BasicBlock<IRNode>> basicBlocks;
+    private List<Pair<Integer,Integer>> edges;
+    public CFGBuilder(List<LinearIRBlock> blockList){
+        basicBlocks =new ArrayList<>();
+        edges = new ArrayList<>();
+        for (var funcLabelBlock : blockList) {
+            build(funcLabelBlock);
+        }
+        cfg = new CFG<>(basicBlocks, edges);
+    }
+
+    private void build(LinearIRBlock block){
+        basicBlocks.add(BasicBlock.buildFromLinearBlock(block));
+        for(var successor : block.getSuccessors()){
+            edges.add(Pair.of(block.getOrd(), successor.getOrd()));
+            build(successor);
+        }
+    }
 
+    public CFG<IRNode> getCFG() {
+        return cfg;
     }
 }
diff --git a/ep20/src/main/java/org/teachfx/antlr4/ep20/pass/cfg/LinearIRBlock.java b/ep20/src/main/java/org/teachfx/antlr4/ep20/pass/cfg/LinearIRBlock.java
@@ -11,9 +11,9 @@
 public class LinearIRBlock {
 
     // Fields
-    private static int LABEL_SEQ = 1;
+    private static int LABEL_SEQ = 0;
     private Kind kind = Kind.CONTINUOUS;
-    private int ord = 1;
+    private int ord = 0;
     private ArrayList<IRNode> stmts;
     private List<LinearIRBlock> successors;
     private List<LinearIRBlock> predecessors;
@@ -120,10 +120,11 @@ public void refJMP(IRNode node) {
     // Utility Methods
     @Override
     public String toString() {
-        var firstInstr = stmts.get(0);
-
-        if (firstInstr instanceof FuncEntryLabel) {
-            return firstInstr.toString();
+        if (stmts.isEmpty()) {
+            return "L" + ord;
+        }
+        if (stmts.get(0) instanceof FuncEntryLabel funcEntryLabel) {
+            return funcEntryLabel.toSource();
         }
         return "L" + ord;
     }
@@ -139,12 +140,18 @@ public String toSource(){
     }
 
     public Label getLabel() {
-        var firstInstr = stmts.get(0);
+        if (stmts.isEmpty()) {
+            return new Label(toString(),scope);
+        }
+
 
+        var firstInstr = stmts.get(0);
         if (firstInstr instanceof FuncEntryLabel funcEntryLabel) {
             return funcEntryLabel;
         }
 
         return new Label(toString(),scope);
     }
+
+
 }
diff --git a/ep20/src/main/java/org/teachfx/antlr4/ep20/pass/cfg/Loc.java b/ep20/src/main/java/org/teachfx/antlr4/ep20/pass/cfg/Loc.java
@@ -15,4 +15,11 @@ public Loc(I instr) {
     public Set<Operand> liveIn;
 
     public Set<Operand> liveOut;
+
+    @Override
+    public String toString() {
+        return "Loc{" +
+                "instr=" + instr +
+                '}';
+    }
 }
diff --git a/ep20/src/main/java/org/teachfx/antlr4/ep20/pass/codegen/CymbolAssembler.java b/ep20/src/main/java/org/teachfx/antlr4/ep20/pass/codegen/CymbolAssembler.java
@@ -70,6 +70,9 @@ public Void visit(CallFunc callFunc) {
 
     @Override
     public Void visit(Label label) {
+        // label不存在嵌套可能，下面这种情况必定是空块导致的label悬空。
+        if (indents > 0) { indents--; }
+
         if (label instanceof FuncEntryLabel){
             emit("%s".formatted(label.toSource()));
         } else {
@@ -88,7 +91,7 @@ public Void visit(JMP jmp) {
 
     @Override
     public Void visit(CJMP cjmp) {
-        emit("brf %s".formatted(cjmp.getElseBlock().toString()));
+        emit("brf %s".formatted(cjmp.getElseBlock().getLabel().toString()));
         indents--;
         return null;
     }

diff --git a/ep20/src/main/java/org/teachfx/antlr4/ep20/pass/ir/CymbolIRBuilder.java b/ep20/src/main/java/org/teachfx/antlr4/ep20/pass/ir/CymbolIRBuilder.java
@@ -11,6 +11,8 @@
 import org.teachfx.antlr4.ep20.ast.stmt.*;
 import org.teachfx.antlr4.ep20.ast.type.TypeNode;
 import org.teachfx.antlr4.ep20.ir.expr.Operand;
+import org.teachfx.antlr4.ep20.pass.cfg.CFG;
+import org.teachfx.antlr4.ep20.pass.cfg.CFGBuilder;
 import org.teachfx.antlr4.ep20.pass.cfg.LinearIRBlock;
 import org.teachfx.antlr4.ep20.ir.IRNode;
 import org.teachfx.antlr4.ep20.ir.Prog;
@@ -25,6 +27,7 @@
 import org.teachfx.antlr4.ep20.symtab.symbol.MethodSymbol;
 import org.teachfx.antlr4.ep20.symtab.symbol.VariableSymbol;
 
+import java.util.Objects;
 import java.util.Optional;
 import java.util.Stack;
 
@@ -418,4 +421,23 @@ protected VarSlot popEvalOperand() {
     protected VarSlot peekEvalOperand() {
         return evalExprStack.peek();
     }
+
+    public CFG<IRNode> getCFG() {
+        for (var func : prog.blockList){
+            insertBlockLabel(func);
+        }
+
+        var cfgBuilder = new CFGBuilder(prog.blockList);
+        return cfgBuilder.getCFG();
+    }
+
+    public void insertBlockLabel(LinearIRBlock startBlock) {
+        var firstInstr = startBlock.getLabel();
+        if (!(firstInstr instanceof FuncEntryLabel)) {
+            startBlock.getStmts().add(0,firstInstr);
+        }
+        for (var successor : startBlock.getSuccessors()) {
+            insertBlockLabel(successor);
+        }
+    }
 }
diff --git a/ep21/README.md b/ep21/README.md
@@ -20,4 +20,23 @@ graph LR
 
 ## DONE
 
-
+```mermaid
+graph TD;
+    A[基本块1] --> B[基本块2]  
+    B --> C[基本块3]  
+    C -->|条件跳转| D[基本块6]  
+    C -->|否则| E[基本块4]  
+    E -->|条件跳转| F[基本块7]  
+    F --> B  
+    E -->|否则| G[基本块5]  
+    G -->|条件跳转| F  
+    G -->|否则| H[基本块8]  
+    H --> I[基本块9]  
+    D --> I  
+    subgraph dec1  
+    A  
+    end  
+    subgraph main  
+        B --> C --> D --> E --> F --> G --> H --> I  
+    end
+```