[cfe-commits] r161972 - in /cfe/trunk: include/clang/Basic/DiagnosticGroups.td include/clang/Basic/DiagnosticSemaKinds.td lib/Sema/SemaDecl.cpp test/Sema/tentative-decls.c

[Fariborz Jahanian]

Author: fjahanian
Date: Wed Aug 15 13:42:26 2012
New Revision: 161972

URL: http://llvm.org/viewvc/llvm-project?rev=161972&view=rev
Log:
Patch to warn about __private_extern__ on tentative definitions
as it does something unexpected (but gcc compatible).
Suggest use of __attribute__((visibility("hidden")))
on declaration instead. // rdar://7703982

Modified:
    cfe/trunk/include/clang/Basic/DiagnosticGroups.td
    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
    cfe/trunk/lib/Sema/SemaDecl.cpp
    cfe/trunk/test/Sema/tentative-decls.c

Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=161972&r1=161971&r2=161972&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Wed Aug 15 13:42:26 2012
@@ -155,6 +155,7 @@
 def ObjCReceiver : DiagGroup<"receiver-expr">;
 def OverlengthStrings : DiagGroup<"overlength-strings">;
 def OverloadedVirtual : DiagGroup<"overloaded-virtual">;
+def PrivateExtern : DiagGroup<"private-extern">;
 def ObjCPropertyImpl : DiagGroup<"objc-property-implementation">;
 def ObjCPropertyNoAttribute : DiagGroup<"objc-property-no-attribute">;
 def ObjCMissingSuperCalls : DiagGroup<"objc-missing-super-calls">;
@@ -371,7 +372,8 @@
     Unused,
     VolatileRegisterVar,
     ObjCMissingSuperCalls,
-    OverloadedVirtual
+    OverloadedVirtual,
+    PrivateExtern
  ]>;
 
 // Thread Safety warnings 

Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=161972&r1=161971&r2=161972&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Wed Aug 15 13:42:26 2012
@@ -1489,6 +1489,11 @@
   "%0 is not literal because it has a user-provided destructor">;
 def note_non_literal_nontrivial_dtor : Note<
   "%0 is not literal because it has a non-trivial destructor">;
+def warn_private_extern : Warning<
+  "Use of __private_extern__ on tentative definition has unexpected"
+  " behaviour - use __attribute__((visibility(\"hidden\"))) on extern"
+  " declaration or definition instead">,
+  InGroup<PrivateExtern>, DefaultIgnore;
 
 // C++11 char16_t/char32_t
 def warn_cxx98_compat_unicode_type : Warning<

Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=161972&r1=161971&r2=161972&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Wed Aug 15 13:42:26 2012
@@ -6754,6 +6754,10 @@
                                  diag::err_abstract_type_in_decl,
                                  AbstractVariableType))
         Var->setInvalidDecl();
+      if (!Type->isDependentType() && !Var->isInvalidDecl() &&
+          Var->getStorageClass() == SC_PrivateExtern)
+        Diag(Var->getLocation(), diag::warn_private_extern);
+        
       return;
 
     case VarDecl::TentativeDefinition:

Modified: cfe/trunk/test/Sema/tentative-decls.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/tentative-decls.c?rev=161972&r1=161971&r2=161972&view=diff
==============================================================================
--- cfe/trunk/test/Sema/tentative-decls.c (original)
+++ cfe/trunk/test/Sema/tentative-decls.c Wed Aug 15 13:42:26 2012
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -fsyntax-only -verify
+// RUN: %clang_cc1 %s -fsyntax-only -Wprivate-extern -verify
 
 // PR3310
 struct a x1; // expected-note 2{{forward declaration of 'struct a'}}
@@ -32,7 +32,8 @@
 static int i3 = 5;
 extern int i3;
 
-__private_extern__ int pExtern;
+// rdar://7703982
+__private_extern__ int pExtern; // expected-warning {{Use of __private_extern__ on tentative definition has unexpected behaviour}}
 int pExtern = 0;
 
 int i4;