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Fix crash in ObjC codegen introduced with 5ab6ee7599 

5ab6ee7599 assumed that if `RValue::isScalar()` returns true then `RValue::getScalarVal` will return a valid value.  This is not the case when the return value is `void` and so void message returns would crash if they hit this path.  This is triggered only for cases where the nil-handling path needs to do something non-trivial (destroy arguments that should be consumed by the callee).

Reviewed By: triplef

Differential Revision: https://reviews.llvm.org/D123898
This commit is contained in:
David Chisnall 2022-07-24 11:56:12 +01:00 committed by David Chisnall
parent 0708771cce
commit 94c3b16978
2 changed files with 29 additions and 5 deletions
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12
clang/lib/CodeGen/CGObjCGNU.cpp
View File

@ -2837,11 +2837,13 @@ CGObjCGNU::GenerateMessageSend(CodeGenFunction &CGF,
// Enter the continuation block and emit a phi if required. // Enter the continuation block and emit a phi if required.
CGF.EmitBlock(continueBB); CGF.EmitBlock(continueBB);
if (msgRet.isScalar()) { if (msgRet.isScalar()) {
llvm::Value *v = msgRet.getScalarVal(); // If the return type is void, do nothing
llvm::PHINode *phi = Builder.CreatePHI(v->getType(), 2); if (llvm::Value *v = msgRet.getScalarVal()) {
phi->addIncoming(v, nonNilPathBB); llvm::PHINode *phi = Builder.CreatePHI(v->getType(), 2);
phi->addIncoming(CGM.EmitNullConstant(ResultType), nilPathBB); phi->addIncoming(v, nonNilPathBB);
msgRet = RValue::get(phi); phi->addIncoming(CGM.EmitNullConstant(ResultType), nilPathBB);
msgRet = RValue::get(phi);
}
} else if (msgRet.isAggregate()) { } else if (msgRet.isAggregate()) {
// Aggregate zeroing is handled in nilCleanupBB when it's required. // Aggregate zeroing is handled in nilCleanupBB when it's required.
} else /* isComplex() */ { } else /* isComplex() */ {

22
clang/test/CodeGenObjC/gnustep2-nontrivial-destructor-argument.mm Normal file
View File

@ -0,0 +1,22 @@
// RUN: %clang_cc1 -triple x86_64-unknow-windows-msvc -S -emit-llvm -fobjc-runtime=gnustep-2.0 -o - %s
// Regression test. Ensure that C++ arguments with non-trivial destructors
// don't crash the compiler.
struct X
{
int a;
~X();
};
@protocol Y
- (void)foo: (X)bar;
@end
void test(id<Y> obj)
{
X a{12};
[obj foo: a];
}