Revert "Remove threshold for lifetime marker insertion of named temporaries"

Revert r222993 while I investigate some MemorySanitizer failures.

llvm-svn: 222995

1 files changed, 26 insertions, 26 deletions

diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index 48ba97d2..959ac9a 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -512,7 +512,10 @@ namespace {
       : Addr(addr), Size(size) {}
 
     void Emit(CodeGenFunction &CGF, Flags flags) override {
-      CGF.EmitLifetimeEnd(Size, Addr);
+      llvm::Value *castAddr = CGF.Builder.CreateBitCast(Addr, CGF.Int8PtrTy);
+      CGF.Builder.CreateCall2(CGF.CGM.getLLVMLifetimeEndFn(),
+                              Size, castAddr)
+        ->setDoesNotThrow();
     }
   };
 }
@@ -832,6 +835,21 @@ static bool shouldUseMemSetPlusStoresToInitialize(llvm::Constant *Init,
          canEmitInitWithFewStoresAfterMemset(Init, StoreBudget);
 }
 
+/// Should we use the LLVM lifetime intrinsics for the given local variable?
+static bool shouldUseLifetimeMarkers(CodeGenFunction &CGF, const VarDecl &D,
+                                     unsigned Size) {
+  // For now, only in optimized builds.
+  if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0)
+    return false;
+
+  // Limit the size of marked objects to 32 bytes. We don't want to increase
+  // compile time by marking tiny objects.
+  unsigned SizeThreshold = 32;
+
+  return Size > SizeThreshold;
+}
+
+
 /// EmitAutoVarDecl - Emit code and set up an entry in LocalDeclMap for a
 /// variable declaration with auto, register, or no storage class specifier.
 /// These turn into simple stack objects, or GlobalValues depending on target.
@@ -841,29 +859,6 @@ void CodeGenFunction::EmitAutoVarDecl(const VarDecl &D) {
   EmitAutoVarCleanups(emission);
 }
 
-/// Emit a lifetime.begin marker if some criteria are satisfied.
-/// \return a pointer to the temporary size Value if a marker was emitted, null
-/// otherwise
-llvm::Value *CodeGenFunction::EmitLifetimeStart(uint64_t Size,
-                                                llvm::Value *Addr) {
-  // For now, only in optimized builds.
-  if (CGM.getCodeGenOpts().OptimizationLevel == 0)
-    return nullptr;
-
-  llvm::Value *SizeV = llvm::ConstantInt::get(Int64Ty, Size);
-  llvm::Value *CastAddr = Builder.CreateBitCast(Addr, Int8PtrTy);
-  Builder.CreateCall2(CGM.getLLVMLifetimeStartFn(), SizeV, CastAddr)
-      ->setDoesNotThrow();
-
-  return SizeV;
-}
-
-void CodeGenFunction::EmitLifetimeEnd(llvm::Value *Size, llvm::Value *Addr) {
-  llvm::Value *CastAddr = Builder.CreateBitCast(Addr, Int8PtrTy);
-  Builder.CreateCall2(CGM.getLLVMLifetimeEndFn(), Size, CastAddr)
-      ->setDoesNotThrow();
-}
-
 /// EmitAutoVarAlloca - Emit the alloca and debug information for a
 /// local variable.  Does not emit initialization or destruction.
 CodeGenFunction::AutoVarEmission
@@ -959,8 +954,13 @@ CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
       // Emit a lifetime intrinsic if meaningful.  There's no point
       // in doing this if we don't have a valid insertion point (?).
       uint64_t size = CGM.getDataLayout().getTypeAllocSize(LTy);
-      if (HaveInsertPoint()) {
-        emission.SizeForLifetimeMarkers = EmitLifetimeStart(size, Alloc);
+      if (HaveInsertPoint() && shouldUseLifetimeMarkers(*this, D, size)) {
+        llvm::Value *sizeV = llvm::ConstantInt::get(Int64Ty, size);
+
+        emission.SizeForLifetimeMarkers = sizeV;
+        llvm::Value *castAddr = Builder.CreateBitCast(Alloc, Int8PtrTy);
+        Builder.CreateCall2(CGM.getLLVMLifetimeStartFn(), sizeV, castAddr)
+          ->setDoesNotThrow();
       } else {
         assert(!emission.useLifetimeMarkers());
       }