1. Caching edge links during CFG construction to avoid duplicate edge…

…s between the same blocks. 2. Constructing the CFG from the LinearIRBuilder blocks instead of the full program. This allows finer grained CFG construction. 3. Adding a helper method to LinearIRBlock to return jump entry blocks for conditional and unconditional jumps. 4. Updating the CFG visualization to reflect the code logic of control flow.
whtoo · Nov 23, 2023 · 8d0ff96 · 8d0ff96
1 parent 72bd985
commit 8d0ff96
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Showing 6 changed files with 135 additions and 44 deletions.
diff --git a/ep18/src/main/resources/t.vm b/ep18/src/main/resources/t.vm
@@ -2,42 +2,43 @@
     load 0
     iconst 1
     isub
-    br L2
-L2:
+    br L1
+L1:
     ret
 .def main: args=0 ,locals=1
     iconst 10
     store 0
-    br L5
-L5:
+    br L4
+L4:
     load 0
     iconst 0
     igt
-    brf L7
-L6:
+    brf L6
+L5:
     load 0
     iconst 5
     igt
-    brf L9
-L8:
+    brf L8
+L7:
     load 0
     print
     load 0
     iconst 7
     ieq
-    brf L9
-L10:
-    iconst 7
-    br L4
+    brf L10
 L9:
+    iconst 7
+    br L3
+L10:
+L8:
     sconst "break"
     print
     load 0
     call dec1()
     store 0
-    br L5
-L7:
-    iconst 0
     br L4
-L4:
+L6:
+    iconst 0
+    br L3
+L3:
     halt
diff --git a/ep20/src/main/java/org/teachfx/antlr4/ep20/Compiler.java b/ep20/src/main/java/org/teachfx/antlr4/ep20/Compiler.java
@@ -49,12 +49,12 @@ public static void main(String[] args) throws IOException {
 
         astRoot.accept(irBuilder);
 
-        var cfg = irBuilder.getCFG();
+        var cfg = irBuilder.getCFG(irBuilder.prog.blockList);
         logger.info("CFG:\n" + cfg.toString());
 
         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/pass/cfg/CFGBuilder.java b/ep20/src/main/java/org/teachfx/antlr4/ep20/pass/cfg/CFGBuilder.java
@@ -3,8 +3,7 @@
 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.*;
 
 public class CFGBuilder {
     private CFG<IRNode> cfg;
@@ -19,10 +18,26 @@ public CFGBuilder(List<LinearIRBlock> blockList){
         cfg = new CFG<>(basicBlocks, edges);
     }
 
+    private static final Set<String> cachedEdgeLinks = new HashSet<>();
+
     private void build(LinearIRBlock block){
+
         basicBlocks.add(BasicBlock.buildFromLinearBlock(block));
+        block.getJumpEntries().ifPresent(entries -> {
+            for(var dest : entries){
+                var key = "%d-%d".formatted(block.getOrd(), dest);
+                if (!cachedEdgeLinks.contains(key)) {
+                    edges.add(Pair.of(block.getOrd(), dest));
+                    cachedEdgeLinks.add("%d-%d".formatted(block.getOrd(), dest));
+                }
+            }
+        });
         for(var successor : block.getSuccessors()){
-            edges.add(Pair.of(block.getOrd(), successor.getOrd()));
+            var key = "%d-%d".formatted(block.getOrd(), successor.getOrd());
+            if (!cachedEdgeLinks.contains(key)) {
+                cachedEdgeLinks.add(key);
+                edges.add(Pair.of(block.getOrd(), successor.getOrd()));
+            }
             build(successor);
         }
     }

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
@@ -5,8 +5,7 @@
 import org.teachfx.antlr4.ep20.symtab.scope.Scope;
 import org.teachfx.antlr4.ep20.utils.Kind;
 
-import java.util.ArrayList;
-import java.util.List;
+import java.util.*;
 
 public class LinearIRBlock {
 
@@ -153,5 +152,27 @@ public Label getLabel() {
         return new Label(toString(),scope);
     }
 
+    public Optional<TreeSet<Integer>> getJumpEntries() {
+        var entries = new TreeSet<Integer>();
+        switch (kind) {
+            case END_BY_CJMP -> {
+                CJMP cjmp = (CJMP) getStmts().getLast();
+                var tid = cjmp.getThenBlock().getOrd();
+                var eid = cjmp.getElseBlock().getOrd();
+                entries.add(tid);
+                entries.add(eid);
+                return Optional.of(entries);
+            }
+            case END_BY_JMP -> {
+                JMP cjmp = (JMP) getStmts().getLast();
+                var tid = cjmp.next.getOrd();
+                entries.add(tid);
+                return Optional.of(entries);
+            }
+            default -> {
+                return Optional.empty();
+            }
+        }
+    }
 
 }
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
@@ -27,6 +27,7 @@
 import org.teachfx.antlr4.ep20.symtab.symbol.MethodSymbol;
 import org.teachfx.antlr4.ep20.symtab.symbol.VariableSymbol;
 
+import java.util.List;
 import java.util.Optional;
 import java.util.Stack;
 
@@ -421,12 +422,12 @@ protected VarSlot peekEvalOperand() {
         return evalExprStack.peek();
     }
 
-    public CFG<IRNode> getCFG() {
-        for (var func : prog.blockList){
+    public CFG<IRNode> getCFG(List<LinearIRBlock> blocks) {
+        for (var func : blocks){
             insertBlockLabel(func);
         }
 
-        var cfgBuilder = new CFGBuilder(prog.blockList);
+        var cfgBuilder = new CFGBuilder(blocks);
         return cfgBuilder.getCFG();
     }
 

diff --git a/ep21/README.md b/ep21/README.md
@@ -21,22 +21,75 @@ 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
+graph TD
+subgraph L0
+Q0["t0 = @0;"]
+Q1["t1 =  1 ;"]
+Q2["t0 SUB t1;"]
+Q3["jmp L1;"]
+end
+subgraph L1
+Q4["ret;"]
+end
+subgraph L2
+Q5["t0 =  10 ;"]
+Q6["@0 = t0;"]
+Q7["jmp L4;"]
+end
+subgraph L4
+Q8["t0 = @0;"]
+Q9["t1 =  0 ;"]
+Q10["t0 GT t1;"]
+Q11["jmpIf t0,L5,L6;"]
+end
+subgraph L5
+Q12["t0 = @0;"]
+Q13["t1 =  5 ;"]
+Q14["t0 GT t1;"]
+Q15["jmpIf t0,L7,L8;"]
+end
+subgraph L7
+Q16["t0 = @0;"]
+Q17["call print(args:1);"]
+Q18["t0 = @0;"]
+Q19["t1 =  7 ;"]
+Q20["t0 EQ t1;"]
+Q21["jmpIf t0,L9,L10;"]
+end
+subgraph L9
+Q22["t0 =  7 ;"]
+Q23["jmp L3;"]
+end
+subgraph L10
+end
+subgraph L8
+Q24["t0 =  'break' ;"]
+Q25["call print(args:1);"]
+Q26["t0 = @0;"]
+Q27["call dec1(args:1);"]
+Q28["@0 = t0;"]
+Q29["jmp L4;"]
+end
+subgraph L6
+Q30["t0 =  0 ;"]
+Q31["jmp L3;"]
+end
+subgraph L3
+Q32["halt;"]
+end
+
+L0 --> L1
+L2 --> L4
+L4 --> L5
+L4 --> L6
+L5 --> L7
+L5 --> L8
+L7 --> L9
+L7 --> L10
+L9 --> L3
+L9 --> L10
+L10 --> L8
+L8 --> L4
+L8 --> L6
+L6 --> L3
 ```