Ensure we track all the stack depths for all break and continue points

correctly.  This should lay the ground work to throw the big switch
and start code gening break and continue in the presense of vlas.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64046 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CGObjC.cpp b/lib/CodeGen/CGObjC.cpp
index a116316641f547aea80eb6c0c13b24fe95348916..efd9299d1a036e57bd45524446f8cb4a8bbb5324 100644 (file)
--- a/lib/CodeGen/CGObjC.cpp
+++ b/lib/CodeGen/CGObjC.cpp
@@ -361,6 +361,11 @@ void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S)
     return;
   }
 
+  // We want to ensure that any vlas between here and when we
+  // push the break and continue context below can be destroyed
+  // when we break 
+  llvm::Value *saveBreakStackDepth = StackDepth;
+
   if (const DeclStmt *SD = dyn_cast<DeclStmt>(S.getElement())) {
     EmitStmt(SD);
     assert(HaveInsertPoint() && "DeclStmt destroyed insert point!");
@@ -446,10 +451,6 @@ void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S)
   llvm::BasicBlock *LoopStart = createBasicBlock("loopstart");
   EmitBlock(LoopStart);
 
-  // We want to ensure there are no vlas between here and when we
-  // push the break and continue context below.
-  llvm::Value *saveStackDepth = StackDepth;
-
   llvm::Value *CounterPtr = CreateTempAlloca(UnsignedLongLTy, "counter.ptr");
   Builder.CreateStore(Zero, CounterPtr);
   
@@ -519,9 +520,8 @@ void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S)
   llvm::BasicBlock *LoopEnd = createBasicBlock("loopend");
   llvm::BasicBlock *AfterBody = createBasicBlock("afterbody");
   
-  assert (StackDepth == saveStackDepth && "vla unhandled in for");
-
-  BreakContinuePush(LoopEnd, AfterBody);
+  // Ensure any vlas created between there and here, are undone
+  BreakContinuePush(LoopEnd, AfterBody, saveBreakStackDepth, StackDepth);
 
   EmitStmt(S.getBody());
   

diff --git a/lib/CodeGen/CGStmt.cpp b/lib/CodeGen/CGStmt.cpp
index c65b8114f37fe2fa28f184f22e323ee953538440..ac97c6329dab1f282382cd5585de9a0a2dd3f13f 100644 (file)
--- a/lib/CodeGen/CGStmt.cpp
+++ b/lib/CodeGen/CGStmt.cpp
@@ -466,6 +466,8 @@ void CodeGenFunction::EmitForStmt(const ForStmt &S) {
 
   EmitBlock(CondBlock);
 
+  llvm::Value *saveStackDepth = StackDepth;
+
   // Evaluate the condition if present.  If not, treat it as a
   // non-zero-constant according to 6.8.5.3p2, aka, true.
   if (S.getCond()) {
@@ -491,8 +493,10 @@ void CodeGenFunction::EmitForStmt(const ForStmt &S) {
     ContinueBlock = CondBlock;  
   
   // Store the blocks to use for break and continue.
-  BreakContinuePush(AfterFor, ContinueBlock);
-  
+  // Ensure any vlas created between there and here, are undone
+  BreakContinuePush(AfterFor, ContinueBlock,
+                    saveStackDepth, saveStackDepth);
+
   // If the condition is true, execute the body of the for stmt.
   EmitStmt(S.getBody());
 
@@ -708,6 +712,9 @@ void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) {
   llvm::SwitchInst *SavedSwitchInsn = SwitchInsn;
   llvm::BasicBlock *SavedCRBlock = CaseRangeBlock;
 
+  // Ensure any vlas created inside are destroyed on break.
+  llvm::Value *saveBreakStackDepth = StackDepth;
+
   // Create basic block to hold stuff that comes after switch
   // statement. We also need to create a default block now so that
   // explicit case ranges tests can have a place to jump to on
@@ -723,9 +730,14 @@ void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) {
   // All break statements jump to NextBlock. If BreakContinueStack is non empty
   // then reuse last ContinueBlock.
   llvm::BasicBlock *ContinueBlock = NULL;
-  if (!BreakContinueStack.empty())
+  llvm::Value *saveContinueStackDepth = NULL;
+  if (!BreakContinueStack.empty()) {
     ContinueBlock = BreakContinueStack.back().ContinueBlock;
-  BreakContinuePush(NextBlock, ContinueBlock);
+    saveContinueStackDepth = BreakContinueStack.back().SaveContinueStackDepth;
+  }
+  // Ensure any vlas created between there and here, are undone
+  BreakContinuePush(NextBlock, ContinueBlock,
+                    saveBreakStackDepth, saveContinueStackDepth);
 
   // Emit switch body.
   EmitStmt(S.getBody());

diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index 4ff3badd99df8dc3a22ab9111f7dcb7cc67be616..068627139d79c1ed9f6558b1610144ce65c03b0a 100644 (file)
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -156,6 +156,12 @@ private:
   /// condition has possibly started a vla.
   void BreakContinuePush(llvm::BasicBlock *bb, llvm::BasicBlock *cb) {
     BreakContinueStack.push_back(BreakContinue(bb, cb, StackDepth,
+                                               StackDepth,
+                                               ObjCEHStack.size()));
+  }
+  void BreakContinuePush(llvm::BasicBlock *bb, llvm::BasicBlock *cb,
+                         llvm::Value *bsd, llvm::Value *csd) {
+    BreakContinueStack.push_back(BreakContinue(bb, cb, bsd, csd,
                                                ObjCEHStack.size()));
   }
 
@@ -169,13 +175,14 @@ private:
   // of the eh stack.
   struct BreakContinue {
     BreakContinue(llvm::BasicBlock *bb, llvm::BasicBlock *cb,
-                  llvm::Value *sd, size_t ehss)
-      : BreakBlock(bb), ContinueBlock(cb), SaveStackDepth(sd),
-        EHStackSize(ehss) {}
+                  llvm::Value *bsd, llvm::Value *csd, size_t ehss)
+      : BreakBlock(bb), ContinueBlock(cb),  SaveBreakStackDepth(bsd),
+        SaveContinueStackDepth(csd), EHStackSize(ehss) {}
       
     llvm::BasicBlock *BreakBlock;
     llvm::BasicBlock *ContinueBlock;
-    llvm::Value *SaveStackDepth;
+    llvm::Value *SaveBreakStackDepth;
+    llvm::Value *SaveContinueStackDepth;
     size_t EHStackSize;
   }; 
   llvm::SmallVector<BreakContinue, 8> BreakContinueStack;