[CodeGenObjC] Fix a crash when attempting to copy a zero-sized bit-field in a non-trivial C struct
Zero sized bit-fields aren't included in the CGRecordLayout, so we shouldn't be
calling EmitLValueForField for them. rdar://60695105
Differential revision: https://reviews.llvm.org/D76782
diff --git a/clang/lib/CodeGen/CGNonTrivialStruct.cpp b/clang/lib/CodeGen/CGNonTrivialStruct.cpp
index 91303ce..4a2c3b2 100644
--- a/clang/lib/CodeGen/CGNonTrivialStruct.cpp
+++ b/clang/lib/CodeGen/CGNonTrivialStruct.cpp
@@ -254,6 +254,10 @@
void visitVolatileTrivial(QualType FT, const FieldDecl *FD,
CharUnits CurStructOffset) {
+ // Zero-length bit-fields don't need to be copied/assigned.
+ if (FD && FD->isZeroLengthBitField(this->Ctx))
+ return;
+
// Because volatile fields can be bit-fields and are individually copied,
// their offset and width are in bits.
uint64_t OffsetInBits =
@@ -543,6 +547,10 @@
std::array<Address, 2> Addrs) {
LValue DstLV, SrcLV;
if (FD) {
+ // No need to copy zero-length bit-fields.
+ if (FD->isZeroLengthBitField(this->CGF->getContext()))
+ return;
+
QualType RT = QualType(FD->getParent()->getTypeForDecl(), 0);
llvm::PointerType *PtrTy = this->CGF->ConvertType(RT)->getPointerTo();
Address DstAddr = this->getAddrWithOffset(Addrs[DstIdx], Offset);