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[Objective-C] C++ Classes with __weak Members non-POD Types when using -fobjc-weak 

Summary: When adding an Objective-C retainable type member to a C++ class, also check the LangOpts.ObjCWeak flag and the lifetime qualifier so __weak qualified Objective-C pointer members cause the class to be a non-POD type with non-trivial special members, so the compiler always emits the necessary runtime calls for copying, moving, and destroying the weak member. Otherwise, Objective-C++ classes with weak Objective-C pointer members compiled with -fobjc-weak exhibit undefined behavior if the C++ class is classified as a POD type.

Reviewers: rsmith, benlangmuir, doug.gregor, rjmccall

Reviewed By: rjmccall

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D31003

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@299008 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Brian Kelley 2017-03-29 17:31:42 +00:00
parent 1895a41ddd
commit b18f3efe98
3 changed files with 74 additions and 8 deletions
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6
lib/AST/DeclCXX.cpp
View File

@ -722,9 +722,7 @@ void CXXRecordDecl::addedMember(Decl *D) {
ASTContext &Context = getASTContext();
QualType T = Context.getBaseElementType(Field->getType());
if (T->isObjCRetainableType() || T.isObjCGCStrong()) {
if (!Context.getLangOpts().ObjCAutoRefCount) {
setHasObjectMember(true);
} else if (T.getObjCLifetime() != Qualifiers::OCL_ExplicitNone) {
if (T.hasNonTrivialObjCLifetime()) {
// Objective-C Automatic Reference Counting:
// If a class has a non-static data member of Objective-C pointer
// type (or array thereof), it is a non-POD type and its
@ -736,6 +734,8 @@ void CXXRecordDecl::addedMember(Decl *D) {
Data.PlainOldData = false;
Data.HasTrivialSpecialMembers = 0;
Data.HasIrrelevantDestructor = false;
} else if (!Context.getLangOpts().ObjCAutoRefCount) {
setHasObjectMember(true);
}
} else if (!T.isCXX98PODType(Context))
data().PlainOldData = false;

7
lib/Sema/SemaDeclCXX.cpp
View File

@ -4399,11 +4399,8 @@ BuildImplicitMemberInitializer(Sema &SemaRef, CXXConstructorDecl *Constructor,
}
}
if (SemaRef.getLangOpts().ObjCAutoRefCount &&
FieldBaseElementType->isObjCRetainableType() &&
FieldBaseElementType.getObjCLifetime() != Qualifiers::OCL_None &&
FieldBaseElementType.getObjCLifetime() != Qualifiers::OCL_ExplicitNone) {
// ARC:
if (FieldBaseElementType.hasNonTrivialObjCLifetime()) {
// ARC and Weak:
// Default-initialize Objective-C pointers to NULL.
CXXMemberInit
= new (SemaRef.Context) CXXCtorInitializer(SemaRef.Context, Field,

69
test/CodeGenObjCXX/objc-weak.mm Normal file
View File

@ -0,0 +1,69 @@
// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -fblocks -fobjc-weak -fobjc-runtime-has-weak -std=c++11 -o - %s | FileCheck %s
struct A { __weak id x; };
id test0() {
A a;
A b = a;
A c(static_cast<A&&>(b));
a = c;
c = static_cast<A&&>(a);
return c.x;
}
// Copy Assignment Operator
// CHECK-LABEL: define linkonce_odr dereferenceable({{[0-9]+}}) %struct.A* @_ZN1AaSERKS_(
// CHECK: [[THISADDR:%this.*]] = alloca [[A:.*]]*
// CHECK: [[OBJECTADDR:%.*]] = alloca [[A:.*]]*
// CHECK: [[THIS:%this.*]] = load [[A]]*, [[A]]** [[THISADDR]]
// CHECK: [[OBJECT:%.*]] = load [[A]]*, [[A]]** [[OBJECTADDR]]
// CHECK: [[T0:%.*]] = getelementptr inbounds [[A]], [[A]]* [[OBJECT]], i32 0, i32 0
// CHECK-NEXT: [[T1:%.*]] = call i8* @objc_loadWeak(i8** [[T0]])
// CHECK-NEXT: [[T2:%.*]] = getelementptr inbounds [[A]], [[A]]* [[THIS]], i32 0, i32 0
// CHECK-NEXT: [[T3:%.*]] = call i8* @objc_storeWeak(i8** [[T2]], i8* [[T1]])
// Move Assignment Operator
// CHECK-LABEL: define linkonce_odr dereferenceable({{[0-9]+}}) %struct.A* @_ZN1AaSEOS_(
// CHECK: [[THISADDR:%this.*]] = alloca [[A:.*]]*
// CHECK: [[OBJECTADDR:%.*]] = alloca [[A:.*]]*
// CHECK: [[THIS:%this.*]] = load [[A]]*, [[A]]** [[THISADDR]]
// CHECK: [[OBJECT:%.*]] = load [[A]]*, [[A]]** [[OBJECTADDR]]
// CHECK: [[T0:%.*]] = getelementptr inbounds [[A]], [[A]]* [[OBJECT]], i32 0, i32 0
// CHECK-NEXT: [[T1:%.*]] = call i8* @objc_loadWeak(i8** [[T0]])
// CHECK-NEXT: [[T2:%.*]] = getelementptr inbounds [[A]], [[A]]* [[THIS]], i32 0, i32 0
// CHECK-NEXT: [[T3:%.*]] = call i8* @objc_storeWeak(i8** [[T2]], i8* [[T1]])
// Default Constructor
// CHECK-LABEL: define linkonce_odr void @_ZN1AC2Ev(
// CHECK: [[THISADDR:%this.*]] = alloca [[A:.*]]*
// CHECK: [[THIS:%this.*]] = load [[A]]*, [[A]]** [[THISADDR]]
// CHECK: [[T0:%.*]] = getelementptr inbounds [[A]], [[A]]* [[THIS]], i32 0, i32 0
// CHECK-NEXT: store i8* null, i8** [[T0]]
// Copy Constructor
// CHECK-LABEL: define linkonce_odr void @_ZN1AC2ERKS_(
// CHECK: [[THISADDR:%this.*]] = alloca [[A:.*]]*
// CHECK: [[OBJECTADDR:%.*]] = alloca [[A:.*]]*
// CHECK: [[THIS:%this.*]] = load [[A]]*, [[A]]** [[THISADDR]]
// CHECK: [[T0:%.*]] = getelementptr inbounds [[A]], [[A]]* [[THIS]], i32 0, i32 0
// CHECK-NEXT: [[OBJECT:%.*]] = load [[A]]*, [[A]]** [[OBJECTADDR]]
// CHECK-NEXT: [[T1:%.*]] = getelementptr inbounds [[A]], [[A]]* [[OBJECT]], i32 0, i32 0
// CHECK-NEXT: call void @objc_copyWeak(i8** [[T0]], i8** [[T1]])
// Move Constructor
// CHECK-LABEL: define linkonce_odr void @_ZN1AC2EOS_(
// CHECK: [[THISADDR:%this.*]] = alloca [[A:.*]]*
// CHECK: [[OBJECTADDR:%.*]] = alloca [[A:.*]]*
// CHECK: [[THIS:%this.*]] = load [[A]]*, [[A]]** [[THISADDR]]
// CHECK: [[T0:%.*]] = getelementptr inbounds [[A]], [[A]]* [[THIS]], i32 0, i32 0
// CHECK-NEXT: [[OBJECT:%.*]] = load [[A]]*, [[A]]** [[OBJECTADDR]]
// CHECK-NEXT: [[T1:%.*]] = getelementptr inbounds [[A]], [[A]]* [[OBJECT]], i32 0, i32 0
// CHECK-NEXT: call void @objc_moveWeak(i8** [[T0]], i8** [[T1]])
// Destructor
// CHECK-LABEL: define linkonce_odr void @_ZN1AD2Ev(
// CHECK: [[THISADDR:%this.*]] = alloca [[A:.*]]*
// CHECK: [[THIS:%this.*]] = load [[A]]*, [[A]]** [[THISADDR]]
// CHECK-NEXT: [[T0:%.*]] = getelementptr inbounds [[A]], [[A]]* [[THIS]], i32 0, i32 0
// CHECK-NEXT: call void @objc_destroyWeak(i8** [[T0]])