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[CodeGen] Emit destructor calls to destruct non-trivial C struct temporaries created by conditional and assignment operators #2034

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Merged
merged 1 commit into from
Oct 24, 2020
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[CodeGen] Emit destructor calls to destruct non-trivial C struct temporaries created by conditional and assignment operators #2034

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14 changes: 14 additions & 0 deletions clang/lib/CodeGen/CGExprAgg.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1214,6 +1214,11 @@ void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {

// Copy into the destination if the assignment isn't ignored.
EmitFinalDestCopy(E->getType(), LHS);

if (!Dest.isIgnored() && !Dest.isExternallyDestructed() &&
E->getType().isDestructedType() == QualType::DK_nontrivial_c_struct)
CGF.pushDestroy(QualType::DK_nontrivial_c_struct, Dest.getAddress(),
E->getType());
}

void AggExprEmitter::
Expand All @@ -1231,6 +1236,11 @@ VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {

// Save whether the destination's lifetime is externally managed.
bool isExternallyDestructed = Dest.isExternallyDestructed();
bool destructNonTrivialCStruct =
!isExternallyDestructed &&
E->getType().isDestructedType() == QualType::DK_nontrivial_c_struct;
isExternallyDestructed |= destructNonTrivialCStruct;
Dest.setExternallyDestructed(isExternallyDestructed);

eval.begin(CGF);
CGF.EmitBlock(LHSBlock);
Expand All @@ -1252,6 +1262,10 @@ VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
Visit(E->getFalseExpr());
eval.end(CGF);

if (destructNonTrivialCStruct)
CGF.pushDestroy(QualType::DK_nontrivial_c_struct, Dest.getAddress(),
E->getType());

CGF.EmitBlock(ContBlock);
}

Expand Down
46 changes: 45 additions & 1 deletion clang/test/CodeGenObjC/strong-in-c-struct.m
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Original file line number Diff line number Diff line change
Expand Up @@ -95,12 +95,13 @@ + (StrongSmall)getStrongSmallClass;
@end

id g0;
StrongSmall g1, g2;

// CHECK: %[[STRUCT_STRONGSMALL:.*]] = type { i32, i8* }
// CHECK: %[[STRUCT_STRONGOUTER:.*]] = type { %[[STRUCT_STRONG:.*]], i8*, double }
// CHECK: %[[STRUCT_STRONG]] = type { %[[STRUCT_TRIVIAL:.*]], i8* }
// CHECK: %[[STRUCT_TRIVIAL]] = type { [4 x i32] }
// CHECK: %[[STRUCT_BLOCK_BYREF_T:.*]] = type { i8*, %[[STRUCT_BLOCK_BYREF_T]]*, i32, i32, i8*, i8*, i8*, %[[STRUCT_STRONGOUTER]] }
// CHECK: %[[STRUCT_STRONGSMALL:.*]] = type { i32, i8* }
// CHECK: %[[STRUCT_STRONGBLOCK:.*]] = type { void ()* }
// CHECK: %[[STRUCT_BITFIELD1:.*]] = type { i8, i8, i8*, i32, i8*, [3 x i32], i8*, double, i8, i8 }

Expand Down Expand Up @@ -900,4 +901,47 @@ void test_zero_bitfield() {
a = b;
}

// CHECK-LABEL: define i8* @test_conditional0(
// CHECK: %[[TMP:.*]] = alloca %[[STRUCT_STRONGSMALL]], align 8

// CHECK: %[[V1:.*]] = bitcast %[[STRUCT_STRONGSMALL]]* %[[TMP]] to i8**
// CHECK: call void @__copy_constructor_8_8_t0w4_s8(i8** %[[V1]], i8** bitcast (%[[STRUCT_STRONGSMALL]]* @g2 to i8**))

// CHECK: %[[V2:.*]] = bitcast %[[STRUCT_STRONGSMALL]]* %[[TMP]] to i8**
// CHECK: call void @__copy_constructor_8_8_t0w4_s8(i8** %[[V2]], i8** bitcast (%[[STRUCT_STRONGSMALL]]* @g1 to i8**))

// CHECK: %[[V5:.*]] = bitcast %[[STRUCT_STRONGSMALL]]* %[[TMP]] to i8**
// CHECK: call void @__destructor_8_s8(i8** %[[V5]])
// CHECK: @llvm.objc.autoreleaseReturnValue

id test_conditional0(int c) {
return (c ? g2 : g1).f1;
}

// CHECK-LABEL: define i8* @test_conditional1(
// CHECK-NOT: call void @__destructor

id test_conditional1(int c) {
calleeStrongSmall(c ? g2 : g1);
}

// CHECK-LABEL: define i8* @test_assignment0(
// CHECK: %[[TMP:.*]] = alloca %[[STRUCT_STRONGSMALL]], align 8
// CHECK: call void @__copy_assignment_8_8_t0w4_s8(i8** bitcast (%[[STRUCT_STRONGSMALL]]* @g2 to i8**), i8** bitcast (%[[STRUCT_STRONGSMALL]]* @g1 to i8**))
// CHECK: %[[V0:.*]] = bitcast %[[STRUCT_STRONGSMALL]]* %[[TMP]] to i8**
// CHECK: call void @__copy_constructor_8_8_t0w4_s8(i8** %[[V0]], i8** bitcast (%[[STRUCT_STRONGSMALL]]* @g2 to i8**))
// CHECK: %[[V3:.*]] = bitcast %[[STRUCT_STRONGSMALL]]* %[[TMP]] to i8**
// CHECK: call void @__destructor_8_s8(i8** %[[V3]])

id test_assignment0(void) {
return (g2 = g1).f1;
}

// CHECK-LABEL: define i8* @test_assignment1(
// CHECK-NOT: call void @__destructor

id test_assignment1(void) {
calleeStrongSmall(g2 = g1);
}

#endif /* USESTRUCT */