-Warc-repeated-use-of-weak: check ivars and variables as well.

Like properties, loading from a weak ivar twice in the same function can
give you inconsistent results if the object is deallocated between the
two loads. It is safer to assign to a strong local variable and use that.

Second half of <rdar://problem/12280249>.

llvm-svn: 164855

1 files changed, 11 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 7951a71e4ed..ebb6cd10652 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -5639,9 +5639,19 @@ void Sema::checkUnsafeExprAssigns(SourceLocation Loc,
   
   if (LHSType.isNull())
     LHSType = LHS->getType();
+
+  Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime();
+
+  if (LT == Qualifiers::OCL_Weak) {
+    DiagnosticsEngine::Level Level =
+      Diags.getDiagnosticLevel(diag::warn_arc_repeated_use_of_weak, Loc);
+    if (Level != DiagnosticsEngine::Ignored)
+      getCurFunction()->markSafeWeakUse(LHS);
+  }
+
   if (checkUnsafeAssigns(Loc, LHSType, RHS))
     return;
-  Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime();
+
   // FIXME. Check for other life times.
   if (LT != Qualifiers::OCL_None)
     return;