[CodeGen][ObjC] Emit a primitive store to store a __strong field in

ExpandTypeFromArgs

This fixes a bug in IRGen where a call to `llvm.objc.storeStrong` was
being emitted to initialize a __strong field of an uninitialized
temporary struct, which caused crashes at runtime.

rdar://problem/51807365
This commit is contained in:
Akira Hatanaka 2019-11-29 09:56:02 -08:00
parent d08dc0655e
commit d8136f14f1
3 changed files with 28 additions and 2 deletions

View File

@ -1047,8 +1047,13 @@ void CodeGenFunction::ExpandTypeFromArgs(
auto imagValue = *AI++;
EmitStoreOfComplex(ComplexPairTy(realValue, imagValue), LV, /*init*/ true);
} else {
// Call EmitStoreOfScalar except when the lvalue is a bitfield to emit a
// primitive store.
assert(isa<NoExpansion>(Exp.get()));
if (LV.isBitField())
EmitStoreThroughLValue(RValue::get(*AI++), LV);
else
EmitStoreOfScalar(*AI++, LV);
}
}

View File

@ -4544,7 +4544,11 @@ RValue CodeGenFunction::EmitRValueForField(LValue LV,
// don't load reference fields.
if (FD->getType()->isReferenceType())
return RValue::get(FieldLV.getPointer(*this));
// Call EmitLoadOfScalar except when the lvalue is a bitfield to emit a
// primitive load.
if (FieldLV.isBitField())
return EmitLoadOfLValue(FieldLV, Loc);
return RValue::get(EmitLoadOfScalar(FieldLV, Loc));
}
llvm_unreachable("bad evaluation kind");
}

View File

@ -0,0 +1,17 @@
// RUN: %clang_cc1 -triple i386-apple-watchos6.0-simulator -emit-llvm -fblocks -fobjc-arc -o - %s | FileCheck %s
// CHECK: %[[STRUCT_S:.*]] = type { i8* }
typedef struct {
id x;
} S;
// CHECK: define void @test0(i8* %[[A_0:.*]])
// CHECK: %[[A:.*]] = alloca %[[STRUCT_S]], align 4
// CHECK: %[[X:.*]] = getelementptr inbounds %[[STRUCT_S]], %[[STRUCT_S]]* %[[A]], i32 0, i32 0
// CHECK: store i8* %[[A_0]], i8** %[[X]], align 4
// CHECK: %[[V0:.*]] = bitcast %[[STRUCT_S]]* %[[A]] to i8**
// CHECK: call void @__destructor_4_s0(i8** %[[V0]]) #2
void test0(S a) {
}