Fixed bug in CFG construction when processing switch statements that contain no

"default" case. In such cases, we now correctly add the CFGBlock representing
the code after the switch statement as a successor to the block terminated by
the switch statement.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@47087 91177308-0d34-0410-b5e6-96231b3b80d8

AST/CFG.cpp

@@ -65,6 +65,7 @@ class VISIBILITY_HIDDEN CFGBuilder : public StmtVisitor<CFGBuilder,CFGBlock*> {
   CFGBlock* ContinueTargetBlock;
   CFGBlock* BreakTargetBlock;
   CFGBlock* SwitchTerminatedBlock;
+  bool      SwitchHasDefaultCase;
   
   // LabelMap records the mapping from Label expressions to their blocks.
   typedef llvm::DenseMap<LabelStmt*,CFGBlock*> LabelMapTy;
@@ -109,6 +110,7 @@ public:
   CFGBlock* VisitBreakStmt(BreakStmt* B);
   CFGBlock* VisitSwitchStmt(SwitchStmt* S);
   CFGBlock* VisitSwitchCase(SwitchCase* S);
+  CFGBlock* VisitDefaultStmt(DefaultStmt* D);
   CFGBlock* VisitIndirectGotoStmt(IndirectGotoStmt* I);
   
 private:
@@ -884,6 +886,9 @@ CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* S) {
   SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
                             save_break(BreakTargetBlock);
   
+  SaveAndRestore<bool> save_has_default_case(SwitchHasDefaultCase);
+  SwitchHasDefaultCase = false;
+  
   // Create a new block that will contain the switch statement.
   SwitchTerminatedBlock = createBlock(false);
   
@@ -900,10 +905,16 @@ CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* S) {
   CFGBlock *BodyBlock = Visit(S->getBody());
   if (Block) FinishBlock(BodyBlock);
 
+  // If we have no "default:" case, the default transition is to the
+  // code following the switch body.
+  if (!SwitchHasDefaultCase)
+    SwitchTerminatedBlock->addSuccessor(SwitchSuccessor);
+  
   // Add the terminator and condition in the switch block.
   SwitchTerminatedBlock->setTerminator(S);
   assert (S->getCond() && "switch condition must be non-NULL");
   Block = SwitchTerminatedBlock;
+  
   return addStmt(S->getCond());
 }
 
@@ -933,6 +944,11 @@ CFGBlock* CFGBuilder::VisitSwitchCase(SwitchCase* S) {
   
   return CaseBlock;    
 }
+  
+CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* D) {
+  SwitchHasDefaultCase = true;
+  return VisitSwitchCase(D);
+}
 
 CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) {
   // Lazily create the indirect-goto dispatch block if there isn't one