r203012 - Capabilities are required to pass a name specifying what type of capability is being annotated. There are currently only two supported names: mutex and role. Adding functionality to check for the capability name and diagnose when it's unexpected.

[Aaron Ballman]

Author: aaronballman
Date: Wed Mar  5 15:47:13 2014
New Revision: 203012

URL: http://llvm.org/viewvc/llvm-project?rev=203012&view=rev
Log:
Capabilities are required to pass a name specifying what type of capability is being annotated. There are currently only two supported names: mutex and role. Adding functionality to check for the capability name and diagnose when it's unexpected.

Note that for backwards compatibility, an unnamed capability will default to being a "mutex." This allows the deprecated lockable attribute to continue to function.

Modified:
    cfe/trunk/include/clang/Basic/Attr.td
    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
    cfe/trunk/lib/Sema/SemaDeclAttr.cpp
    cfe/trunk/test/Sema/attr-capabilities.c

Modified: cfe/trunk/include/clang/Basic/Attr.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/Attr.td?rev=203012&r1=203011&r2=203012&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/Attr.td (original)
+++ cfe/trunk/include/clang/Basic/Attr.td Wed Mar  5 15:47:13 2014
@@ -1306,6 +1306,10 @@ def Capability : InheritableAttr {
                     [GNU<"shared_capability">,
                      CXX11<"clang","shared_capability">]>];
   let Documentation = [Undocumented];
+  let AdditionalMembers = [{
+    bool isMutex() const { return getName().equals_lower("mutex"); }
+    bool isRole() const { return getName().equals_lower("role"); }
+  }];
 }
 
 def AssertCapability : InheritableAttr {

Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=203012&r1=203011&r2=203012&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Wed Mar  5 15:47:13 2014
@@ -2153,6 +2153,9 @@ def note_overridden_method : Note<
   "overridden method is here">;
 
 // Thread Safety Attributes
+def warn_invalid_capability_name : Warning<
+  "invalid capability name '%0'; capability name must be 'mutex' or 'role'">,
+  InGroup<ThreadSafetyAttributes>, DefaultIgnore;
 def warn_thread_attribute_ignored : Warning<
   "ignoring %0 attribute because its argument is invalid">,
   InGroup<ThreadSafetyAttributes>, DefaultIgnore;

Modified: cfe/trunk/lib/Sema/SemaDeclAttr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclAttr.cpp?rev=203012&r1=203011&r2=203012&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDeclAttr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDeclAttr.cpp Wed Mar  5 15:47:13 2014
@@ -3892,12 +3892,20 @@ static void handleCapabilityAttr(Sema &S
   // parameters. However, semantically, both attributes represent the same
   // concept, and so they use the same semantic attribute. Eventually, the
   // lockable attribute will be removed.
-  StringRef N;
+  //
+  // For backwards compatibility, any capability which has no specified string
+  // literal will be considered a "mutex."
+  StringRef N("mutex");
   SourceLocation LiteralLoc;
   if (Attr.getKind() == AttributeList::AT_Capability &&
       !S.checkStringLiteralArgumentAttr(Attr, 0, N, &LiteralLoc))
     return;
 
+  // Currently, there are only two names allowed for a capability: role and
+  // mutex (case insensitive). Diagnose other capability names.
+  if (!N.equals_lower("mutex") && !N.equals_lower("role"))
+    S.Diag(LiteralLoc, diag::warn_invalid_capability_name) << N;
+
   D->addAttr(::new (S.Context) CapabilityAttr(Attr.getRange(), S.Context, N,
                                         Attr.getAttributeSpellingListIndex()));
 }

Modified: cfe/trunk/test/Sema/attr-capabilities.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/attr-capabilities.c?rev=203012&r1=203011&r2=203012&view=diff
==============================================================================
--- cfe/trunk/test/Sema/attr-capabilities.c (original)
+++ cfe/trunk/test/Sema/attr-capabilities.c Wed Mar  5 15:47:13 2014
@@ -1,9 +1,12 @@
 // RUN: %clang_cc1 -fsyntax-only -Wthread-safety -verify %s
 
-struct __attribute__((capability("thread role"))) ThreadRole {};
+struct __attribute__((capability("role"))) ThreadRole {};
 struct __attribute__((shared_capability("mutex"))) Mutex {};
 struct NotACapability {};
 
+// Test an invalid capability name
+struct __attribute__((capability("wrong"))) IncorrectName {}; // expected-warning {{invalid capability name 'wrong'; capability name must be 'mutex' or 'role'}}
+
 int Test1 __attribute__((capability("test1")));  // expected-error {{'capability' attribute only applies to structs}}
 int Test2 __attribute__((shared_capability("test2"))); // expected-error {{'shared_capability' attribute only applies to structs}}
 int Test3 __attribute__((acquire_capability("test3")));  // expected-error {{'acquire_capability' attribute only applies to functions}}