Commit 088f3360 authored by yronglin's avatar yronglin Committed by Tobias Hieta
Browse files

[CodeGen][ARM] Fix ARMABIInfo::EmitVAAarg crash with empty record type variadic arg

Fix ARMABIInfo::EmitVAAarg crash with empty record type variadic arg

Open issue: https://github.com/llvm/llvm-project/issues/58794

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D138137

(cherry picked from commit 80f44464)
parent abcd0341
......@@ -7047,10 +7047,10 @@ Address ARMABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
// Empty records are ignored for parameter passing purposes.
if (isEmptyRecord(getContext(), Ty, true)) {
Address Addr = Address(CGF.Builder.CreateLoad(VAListAddr),
getVAListElementType(CGF), SlotSize);
Addr = CGF.Builder.CreateElementBitCast(Addr, CGF.ConvertTypeForMem(Ty));
return Addr;
VAListAddr = CGF.Builder.CreateElementBitCast(VAListAddr, CGF.Int8PtrTy);
auto *Load = CGF.Builder.CreateLoad(VAListAddr);
Address Addr = Address(Load, CGF.Int8Ty, SlotSize);
return CGF.Builder.CreateElementBitCast(Addr, CGF.ConvertTypeForMem(Ty));
}
CharUnits TySize = getContext().getTypeSizeInChars(Ty);
......
// RUN: %clang -Xclang -no-opaque-pointers -mfloat-abi=soft -target arm-linux-gnu -emit-llvm -S -o - %s | FileCheck %s
struct Empty {};
struct Empty emptyvar;
void take_args(int a, ...) {
// CHECK: [[ALLOCA_VA_LIST:%[a-zA-Z0-9._]+]] = alloca %struct.__va_list, align 4
// CHECK: call void @llvm.va_start
// CHECK-NEXT: [[AP_ADDR:%[a-zA-Z0-9._]+]] = bitcast %struct.__va_list* [[ALLOCA_VA_LIST]] to i8**
// CHECK-NEXT: [[LOAD_AP:%[a-zA-Z0-9._]+]] = load i8*, i8** [[AP_ADDR]], align 4
// CHECK-NEXT: [[EMPTY_PTR:%[a-zA-Z0-9._]+]] = bitcast i8* [[LOAD_AP]] to %struct.Empty*
// It's conceivable that EMPTY_PTR may not actually be a valid pointer
// (e.g. it's at the very bottom of the stack and the next page is
// invalid). This doesn't matter provided it's never loaded (there's no
// well-defined way to tell), but it becomes a problem if we do try to use it.
// CHECK-NOT: load %struct.Empty, %struct.Empty* [[EMPTY_PTR]]
__builtin_va_list l;
__builtin_va_start(l, a);
emptyvar = __builtin_va_arg(l, struct Empty);
__builtin_va_end(l);
}
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