[cfe-commits] r133168 - in /cfe/trunk: include/clang/Basic/DiagnosticSemaKinds.td lib/Sema/SemaExpr.cpp test/SemaObjC/arc.m

[Fariborz Jahanian]

Author: fjahanian
Date: Thu Jun 16 12:29:56 2011
New Revision: 133168

URL: http://llvm.org/viewvc/llvm-project?rev=133168&view=rev
Log:
arc: diagnose dereferencing a __weak pointer which may be
null at any time. // rdar://9612030

Modified:
    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
    cfe/trunk/lib/Sema/SemaExpr.cpp
    cfe/trunk/test/SemaObjC/arc.m

Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=133168&r1=133167&r2=133168&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Thu Jun 16 12:29:56 2011
@@ -2815,6 +2815,9 @@
   "member reference base type %0 is not a structure or union">;
 def err_typecheck_member_reference_ivar : Error<
   "%0 does not have a member named %1">;
+def error_arc_weak_ivar_access : Error<
+  "dereferencing a __weak pointer is not allowed due to possible "
+  "null value caused by race condition, assign it to strong variable first">;
 def err_typecheck_member_reference_arrow : Error<
   "member reference type %0 is not a pointer">;
 def err_typecheck_member_reference_suggestion : Error<

Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=133168&r1=133167&r2=133168&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Thu Jun 16 12:29:56 2011
@@ -4333,6 +4333,16 @@
         Diag(MemberLoc, diag::error_protected_ivar_access)
           << IV->getDeclName();
     }
+    if (getLangOptions().ObjCAutoRefCount) {
+      Expr *BaseExp = BaseExpr.get()->IgnoreParenImpCasts();
+      if (UnaryOperator *UO = dyn_cast<UnaryOperator>(BaseExp))
+        if (UO->getOpcode() == UO_Deref)
+          BaseExp = UO->getSubExpr()->IgnoreParenCasts();
+      
+      if (DeclRefExpr *DE = dyn_cast<DeclRefExpr>(BaseExp))
+        if (DE->getType().getObjCLifetime() == Qualifiers::OCL_Weak)
+          Diag(DE->getLocation(), diag::error_arc_weak_ivar_access);
+    }
 
     return Owned(new (Context) ObjCIvarRefExpr(IV, IV->getType(),
                                                MemberLoc, BaseExpr.take(),

Modified: cfe/trunk/test/SemaObjC/arc.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/arc.m?rev=133168&r1=133167&r2=133168&view=diff
==============================================================================
--- cfe/trunk/test/SemaObjC/arc.m (original)
+++ cfe/trunk/test/SemaObjC/arc.m Thu Jun 16 12:29:56 2011
@@ -548,3 +548,18 @@
     int k = (pcls->isa ? i : j); // expected-error {{member reference base type 'Class<PTest31>' is not a structure or union}}
     return cls->isa ? i : j; // expected-error {{member reference base type 'Class' is not a structure or union}}
 }
+
+// rdar://9612030
+ at interface ITest32 {
+ at public
+ id ivar;
+}
+ at end
+
+id Test32(__weak ITest32 *x) {
+  __weak ITest32 *y;
+  x->ivar = 0; // expected-error {{dereferencing a __weak pointer is not allowed}}
+  return y ? y->ivar     // expected-error {{dereferencing a __weak pointer is not allowed}}
+           : (*x).ivar;  // expected-error {{dereferencing a __weak pointer is not allowed}}
+}
+