Rename CodeGenFunction::EmitMemSetToZero to EmitNullInitialization. Handle setting null data member pointers correctly. Fixes PR7139.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@104387 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index d3bf164..222dcc4 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -472,7 +472,23 @@
CGM.ErrorUnsupported(S, Type, OmitOnError);
}
-void CodeGenFunction::EmitMemSetToZero(llvm::Value *DestPtr, QualType Ty) {
+void
+CodeGenFunction::EmitNullInitialization(llvm::Value *DestPtr, QualType Ty) {
+ // If the type contains a pointer to data member we can't memset it to zero.
+ // Instead, create a null constant and copy it to the destination.
+ if (CGM.getTypes().ContainsPointerToDataMember(Ty)) {
+ llvm::Constant *NullConstant = CGM.EmitNullConstant(Ty);
+
+ llvm::GlobalVariable *NullVariable =
+ new llvm::GlobalVariable(CGM.getModule(), NullConstant->getType(),
+ /*isConstant=*/true,
+ llvm::GlobalVariable::PrivateLinkage,
+ NullConstant, llvm::Twine());
+ EmitAggregateCopy(DestPtr, NullVariable, Ty, /*isVolatile=*/false);
+ return;
+ }
+
+
// Ignore empty classes in C++.
if (getContext().getLangOptions().CPlusPlus) {
if (const RecordType *RT = Ty->getAs<RecordType>()) {
@@ -481,6 +497,9 @@
}
}
+ // Otherwise, just memset the whole thing to zero. This is legal
+ // because in LLVM, all default initializers (other than the ones we just
+ // handled above) are guaranteed to have a bit pattern of all zeros.
const llvm::Type *BP = llvm::Type::getInt8PtrTy(VMContext);
if (DestPtr->getType() != BP)
DestPtr = Builder.CreateBitCast(DestPtr, BP, "tmp");