> On May 23, 2016, at 8:15 PM, Bob Wilson <bob.wil...@apple.com> wrote:
>
> Revision r211132 was supposed to disable -Warc-repeated-use-of-weak for
> Objective-C properties marked with the IBOutlet attribute. Those properties
> are supposed to be weak but they are only accessed from the main thread so
> there is no risk of asynchronous updates setting them to nil. That
> combination makes -Warc-repeated-use-of-weak very noisy. The previous change
> only handled one kind of access to weak IBOutlet properties. Instead of
> trying to add checks for all the different kinds of property accesses, this
> patch removes the previous special case check and adds a check at the point
> where the diagnostic is reported.
The approach looks good to me in general.
> diff --git lib/Sema/AnalysisBasedWarnings.cpp
> lib/Sema/AnalysisBasedWarnings.cpp
> index 3f2c41b..eb45315 100644
> --- lib/Sema/AnalysisBasedWarnings.cpp
> +++ lib/Sema/AnalysisBasedWarnings.cpp
> @@ -1334,6 +1334,12 @@ static void diagnoseRepeatedUseOfWeak(Sema &S,
> else
> llvm_unreachable("Unexpected weak object kind!");
>
> + // Do not warn about IBOutlet weak property receivers being set to null
> + // since they are typically only used from the main thread.
> + if (const ObjCPropertyDecl *Prop = dyn_cast<ObjCPropertyDecl>(D))
> + if (Prop->hasAttr<IBOutletAttr>())
> + continue;
> +
> // Show the first time the object was read.
> S.Diag(FirstRead->getLocStart(), DiagKind)
> << int(ObjectKind) << D << int(FunctionKind)
Should we guard the call to diagnoseRepeatedUseOfWeak, instead of checking the
decl inside a loop in diagnoseRepeatedUseOfWeak?
if (S.getLangOpts().ObjCWeak &&
!Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, D->getLocStart()))
diagnoseRepeatedUseOfWeak(S, fscope, D, AC.getParentMap());
—> check IBOutlet here?
> diff --git lib/Sema/SemaPseudoObject.cpp lib/Sema/SemaPseudoObject.cpp
> index 62c823b..c93d800 100644
> --- lib/Sema/SemaPseudoObject.cpp
> +++ lib/Sema/SemaPseudoObject.cpp
> @@ -578,7 +578,7 @@ bool ObjCPropertyOpBuilder::isWeakProperty() const {
> if (RefExpr->isExplicitProperty()) {
> const ObjCPropertyDecl *Prop = RefExpr->getExplicitProperty();
> if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak)
> - return !Prop->hasAttr<IBOutletAttr>();
> + return true;
>
> T = Prop->getType();
> } else if (Getter) {
I wonder if this change is necessary to make the testing case pass, or is it
introduced for clarity, to better reflect the function name isWeakProperty?
Thanks,
Manman
> rdar://problem/21366461
>
> <clang.patch>
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