[cfe-commits] r41299 - /cfe/trunk/AST/CFG.cpp

[Ted Kremenek]

Author: kremenek
Date: Wed Aug 22 16:51:58 2007
New Revision: 41299

URL: http://llvm.org/viewvc/llvm-project?rev=41299&view=rev
Log:
Added support for "break" statements in source-level ASTs.
Some comment cleanups.

Modified:
    cfe/trunk/AST/CFG.cpp

Modified: cfe/trunk/AST/CFG.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/AST/CFG.cpp?rev=41299&r1=41298&r2=41299&view=diff

==============================================================================
--- cfe/trunk/AST/CFG.cpp (original)
+++ cfe/trunk/AST/CFG.cpp Wed Aug 22 16:51:58 2007
@@ -56,6 +56,7 @@
   CFGBlock* Exit;
   CFGBlock* Succ;
   CFGBlock* ContinueTargetBlock;
+  CFGBlock* BreakTargetBlock;
   unsigned NumBlocks;
   
   typedef llvm::DenseMap<LabelStmt*,CFGBlock*> LabelMapTy;
@@ -66,7 +67,7 @@
   
 public:  
   explicit CFGBuilder() : cfg(NULL), Block(NULL), Exit(NULL), Succ(NULL),
-                          ContinueTargetBlock(NULL),
+                          ContinueTargetBlock(NULL), BreakTargetBlock(NULL),
                           NumBlocks(0) {
     // Create an empty CFG.
     cfg = new CFG();                        
@@ -336,11 +337,15 @@
       
       // Save the current values for Block, Succ, and ContinueTargetBlock
       SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ),
-                                save_continue(ContinueTargetBlock);
+                                save_continue(ContinueTargetBlock),
+                                save_break(BreakTargetBlock);
       
       // All continues within this loop should go to the condition block
       ContinueTargetBlock = ConditionBlock;
       
+      // All breaks should go to the code that follows the loop.
+      BreakTargetBlock = Block;
+      
       // create a new block to contain the body.      
       Block = createBlock();
       
@@ -389,11 +394,15 @@
       
       // Save the current values for Block, Succ, and ContinueTargetBlock
       SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ),
-                                save_continue(ContinueTargetBlock);
+                                save_continue(ContinueTargetBlock),
+                                save_break(BreakTargetBlock);
 
       // All continues within this loop should go to the condition block
       ContinueTargetBlock = ConditionBlock;
       
+      // All breaks should go to the code that follows the loop.
+      BreakTargetBlock = Block;
+      
       // NULL out Block to force lazy instantiation of blocks for the body.
       Block = NULL;
       
@@ -403,6 +412,8 @@
       ConditionBlock->addSuccessor(BodyBlock);
     }
     
+    // Link up the condition block with the code that follows the loop.
+    // (the false branch).
     ConditionBlock->addSuccessor(Block);
     
     // There can be no more statements in the condition block
@@ -414,7 +425,7 @@
   }
   
   CFGBlock* VisitContinueStmt(ContinueStmt* C) {
-    // While is a control-flow statement.  Thus we stop processing the
+    // "continue" is a control-flow statement.  Thus we stop processing the
     // current block.
     if (Block) FinishBlock(Block);
     
@@ -429,6 +440,22 @@
     return Block;
   }
   
+  CFGBlock* VisitBreakStmt(BreakStmt* B) {
+    // "break" is a control-flow statement.  Thus we stop processing the
+    // current block.
+    if (Block) FinishBlock(Block);
+    
+    // Now create a new block that ends with the continue statement.
+    Block = createBlock(false);
+    Block->setTerminator(B);
+    
+    // FIXME: We should gracefully handle breaks without resolved targets.
+    assert (BreakTargetBlock);
+    
+    Block->addSuccessor(BreakTargetBlock);
+    return Block;  
+  }
+  
 };
 
 // BuildCFG - A helper function that builds CFGs from ASTS.