Objective-C ARC. Do not warn about properties with both

IBOutlet and weak attributes when accessed being
unpredictably set to nil because usage of such properties
are always single threaded and its ivar cannot be set
to nil asynchronously. // rdar://15885642

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211132 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Sema/ScopeInfo.cpp b/lib/Sema/ScopeInfo.cpp
index d9b2ca310a89869c38e59dd8695748b026291315..4d079e705f625051fdf8c2bba87086c85c8ff9fc 100644 (file)
--- a/lib/Sema/ScopeInfo.cpp
+++ b/lib/Sema/ScopeInfo.cpp
@@ -158,8 +158,14 @@ void FunctionScopeInfo::markSafeWeakUse(const Expr *E) {
 
   // Has this weak object been seen before?
   FunctionScopeInfo::WeakObjectUseMap::iterator Uses;
-  if (const ObjCPropertyRefExpr *RefExpr = dyn_cast<ObjCPropertyRefExpr>(E))
-    Uses = WeakObjectUses.find(WeakObjectProfileTy(RefExpr));
+  if (const ObjCPropertyRefExpr *RefExpr = dyn_cast<ObjCPropertyRefExpr>(E)) {
+    if (isa<OpaqueValueExpr>(RefExpr->getBase()))
+     Uses = WeakObjectUses.find(WeakObjectProfileTy(RefExpr));
+    else {
+      markSafeWeakUse(RefExpr->getBase());
+      return;
+    }
+  }
   else if (const ObjCIvarRefExpr *IvarE = dyn_cast<ObjCIvarRefExpr>(E))
     Uses = WeakObjectUses.find(WeakObjectProfileTy(IvarE));
   else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))

diff --git a/lib/Sema/SemaExprObjC.cpp b/lib/Sema/SemaExprObjC.cpp
index ffb6b037ec0fc387a0a74495c744d7b53c8c304b..c6a7d7c13dcc3c3fc3e02aae62884c73bba10ff5 100644 (file)
--- a/lib/Sema/SemaExprObjC.cpp
+++ b/lib/Sema/SemaExprObjC.cpp
@@ -2640,7 +2640,14 @@ ExprResult Sema::BuildInstanceMessage(Expr *Receiver,
   }
 
   if (getLangOpts().ObjCAutoRefCount) {
-    DiagnoseARCUseOfWeakReceiver(*this, Receiver);
+    // Do not warn about IBOutlet weak property receivers being set to null
+    // as this cannot asynchronously happen.
+    bool WarnWeakReceiver = true;
+    if (isImplicit && Method)
+      if (const ObjCPropertyDecl *PropertyDecl = Method->findPropertyDecl())
+        WarnWeakReceiver = !PropertyDecl->hasAttr<IBOutletAttr>();
+    if (WarnWeakReceiver)
+      DiagnoseARCUseOfWeakReceiver(*this, Receiver);
     
     // In ARC, annotate delegate init calls.
     if (Result->getMethodFamily() == OMF_init &&

diff --git a/lib/Sema/SemaPseudoObject.cpp b/lib/Sema/SemaPseudoObject.cpp
index eaf170c176bcfbb31649868f9d41b0f9e28db7af..35684b4fa22a1b33259236c0b3045acd7311ac78 100644 (file)
--- a/lib/Sema/SemaPseudoObject.cpp
+++ b/lib/Sema/SemaPseudoObject.cpp
@@ -542,7 +542,7 @@ bool ObjCPropertyOpBuilder::isWeakProperty() const {
   if (RefExpr->isExplicitProperty()) {
     const ObjCPropertyDecl *Prop = RefExpr->getExplicitProperty();
     if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak)
-      return true;
+      return !Prop->hasAttr<IBOutletAttr>();
 
     T = Prop->getType();
   } else if (Getter) {
@@ -816,13 +816,20 @@ ExprResult ObjCPropertyOpBuilder::buildRValueOperation(Expr *op) {
 
   // As a special case, if the method returns 'id', try to get
   // a better type from the property.
-  if (RefExpr->isExplicitProperty() && result.get()->isRValue() &&
-      result.get()->getType()->isObjCIdType()) {
+  if (RefExpr->isExplicitProperty() && result.get()->isRValue()) {
     QualType propType = RefExpr->getExplicitProperty()->getType();
-    if (const ObjCObjectPointerType *ptr
-          = propType->getAs<ObjCObjectPointerType>()) {
-      if (!ptr->isObjCIdType())
-        result = S.ImpCastExprToType(result.get(), propType, CK_BitCast);
+    if (result.get()->getType()->isObjCIdType()) {
+      if (const ObjCObjectPointerType *ptr
+            = propType->getAs<ObjCObjectPointerType>()) {
+        if (!ptr->isObjCIdType())
+          result = S.ImpCastExprToType(result.get(), propType, CK_BitCast);
+      }
+    }
+    if (S.getLangOpts().ObjCAutoRefCount) {
+      Qualifiers::ObjCLifetime LT = propType.getObjCLifetime();
+      if (LT == Qualifiers::OCL_Weak)
+        if (!S.Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, RefExpr->getLocation()))
+              S.getCurFunction()->markSafeWeakUse(RefExpr);
     }
   }
 

diff --git a/test/SemaObjC/iboutlet.m b/test/SemaObjC/iboutlet.m
index 3c7f9581e663592924cfdab9b6b68216edf3dd40..63eac9af8a5204403911bd5b7a7a979d7fc37ef5 100644 (file)
--- a/test/SemaObjC/iboutlet.m
+++ b/test/SemaObjC/iboutlet.m
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -fsyntax-only -Wno-objc-root-class -verify %s
-// RUN: %clang_cc1 -x objective-c++ -fsyntax-only -Wno-objc-root-class -verify %s
+// RUN: %clang_cc1 -fsyntax-only -fobjc-arc -Wno-objc-root-class -Wreceiver-is-weak -Warc-repeated-use-of-weak -fobjc-runtime-has-weak -verify %s
+// RUN: %clang_cc1 -x objective-c++ -fsyntax-only -fobjc-arc -Wno-objc-root-class -Wreceiver-is-weak -Warc-repeated-use-of-weak -fobjc-runtime-has-weak -verify %s
 // rdar://11448209
 
 #define READONLY readonly
@@ -40,3 +40,15 @@
 @implementation RKTFHView
 @synthesize synthReadOnlyReadWrite=_synthReadOnlyReadWrite;
 @end
+
+// rdar://15885642
+@interface WeakOutlet 
+@property IBOutlet __weak WeakOutlet* WeakProp;
+@end
+
+WeakOutlet* func() {
+  __weak WeakOutlet* pwi;
+  pwi.WeakProp = (WeakOutlet*)0;
+  pwi.WeakProp = pwi.WeakProp;
+  return pwi.WeakProp;
+}