Merge google-perftools r109 (the current contents of third_party/tcmalloc/vendor)

third_party/tcmalloc/chromium/src/base/thread_annotations.h

Index: third_party/tcmalloc/chromium/src/base/thread_annotations.h
===================================================================
--- third_party/tcmalloc/chromium/src/base/thread_annotations.h	(revision 87277)
+++ third_party/tcmalloc/chromium/src/base/thread_annotations.h	(working copy)
@@ -45,15 +45,23 @@
 #ifndef BASE_THREAD_ANNOTATIONS_H_
 #define BASE_THREAD_ANNOTATIONS_H_
 
-#if defined(__GNUC__) && defined(__SUPPORT_TS_ANNOTATION__) && (!defined(SWIG))
 
+#if defined(__GNUC__) \
+  && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4)) \
+  && defined(__SUPPORT_TS_ANNOTATION__) && (!defined(SWIG))
+#define THREAD_ANNOTATION_ATTRIBUTE__(x)   __attribute__((x))
+#else
+#define THREAD_ANNOTATION_ATTRIBUTE__(x)   // no-op
+#endif
+
+
 // Document if a shared variable/field needs to be protected by a lock.
 // GUARDED_BY allows the user to specify a particular lock that should be
 // held when accessing the annotated variable, while GUARDED_VAR only
 // indicates a shared variable should be guarded (by any lock). GUARDED_VAR
 // is primarily used when the client cannot express the name of the lock.
-#define GUARDED_BY(x)          __attribute__ ((guarded_by(x)))
-#define GUARDED_VAR            __attribute__ ((guarded))
+#define GUARDED_BY(x)          THREAD_ANNOTATION_ATTRIBUTE__(guarded_by(x))
+#define GUARDED_VAR            THREAD_ANNOTATION_ATTRIBUTE__(guarded)
 
 // Document if the memory location pointed to by a pointer should be guarded
 // by a lock when dereferencing the pointer. Similar to GUARDED_VAR,
@@ -63,90 +71,64 @@
 // q, which is guarded by mu1, points to a shared memory location that is
 // guarded by mu2, q should be annotated as follows:
 //     int *q GUARDED_BY(mu1) PT_GUARDED_BY(mu2);
-#define PT_GUARDED_BY(x)       __attribute__ ((point_to_guarded_by(x)))
-#define PT_GUARDED_VAR         __attribute__ ((point_to_guarded))
+#define PT_GUARDED_BY(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(point_to_guarded_by(x))
+#define PT_GUARDED_VAR \
+  THREAD_ANNOTATION_ATTRIBUTE__(point_to_guarded)
 
 // Document the acquisition order between locks that can be held
 // simultaneously by a thread. For any two locks that need to be annotated
 // to establish an acquisition order, only one of them needs the annotation.
 // (i.e. You don't have to annotate both locks with both ACQUIRED_AFTER
 // and ACQUIRED_BEFORE.)
-#define ACQUIRED_AFTER(...)    __attribute__ ((acquired_after(__VA_ARGS__)))
-#define ACQUIRED_BEFORE(...)   __attribute__ ((acquired_before(__VA_ARGS__)))
+#define ACQUIRED_AFTER(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(acquired_after(x))
+#define ACQUIRED_BEFORE(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(acquired_before(x))
 
 // The following three annotations document the lock requirements for
 // functions/methods.
 
 // Document if a function expects certain locks to be held before it is called
-#define EXCLUSIVE_LOCKS_REQUIRED(...) \
-  __attribute__ ((exclusive_locks_required(__VA_ARGS__)))
+#define EXCLUSIVE_LOCKS_REQUIRED(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(exclusive_locks_required(x))
 
-#define SHARED_LOCKS_REQUIRED(...) \
-  __attribute__ ((shared_locks_required(__VA_ARGS__)))
+#define SHARED_LOCKS_REQUIRED(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(shared_locks_required(x))
 
 // Document the locks acquired in the body of the function. These locks
 // cannot be held when calling this function (as google3's Mutex locks are
 // non-reentrant).
-#define LOCKS_EXCLUDED(...)    __attribute__ ((locks_excluded(__VA_ARGS__)))
+#define LOCKS_EXCLUDED(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(locks_excluded(x))
 
 // Document the lock the annotated function returns without acquiring it.
-#define LOCK_RETURNED(x)       __attribute__ ((lock_returned(x)))
+#define LOCK_RETURNED(x)       THREAD_ANNOTATION_ATTRIBUTE__(lock_returned(x))
 
 // Document if a class/type is a lockable type (such as the Mutex class).
-#define LOCKABLE               __attribute__ ((lockable))
+#define LOCKABLE               THREAD_ANNOTATION_ATTRIBUTE__(lockable)
 
 // Document if a class is a scoped lockable type (such as the MutexLock class).
-#define SCOPED_LOCKABLE        __attribute__ ((scoped_lockable))
+#define SCOPED_LOCKABLE        THREAD_ANNOTATION_ATTRIBUTE__(scoped_lockable)
 
 // The following annotations specify lock and unlock primitives.
-#define EXCLUSIVE_LOCK_FUNCTION(...) \
-  __attribute__ ((exclusive_lock(__VA_ARGS__)))
+#define EXCLUSIVE_LOCK_FUNCTION(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(exclusive_lock(x))
 
-#define SHARED_LOCK_FUNCTION(...) \
-  __attribute__ ((shared_lock(__VA_ARGS__)))
+#define SHARED_LOCK_FUNCTION(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(shared_lock(x))
 
-#define EXCLUSIVE_TRYLOCK_FUNCTION(...) \
-  __attribute__ ((exclusive_trylock(__VA_ARGS__)))
+#define EXCLUSIVE_TRYLOCK_FUNCTION(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(exclusive_trylock(x))
 
-#define SHARED_TRYLOCK_FUNCTION(...) \
-  __attribute__ ((shared_trylock(__VA_ARGS__)))
+#define SHARED_TRYLOCK_FUNCTION(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(shared_trylock(x))
 
-#define UNLOCK_FUNCTION(...)   __attribute__ ((unlock(__VA_ARGS__)))
+#define UNLOCK_FUNCTION(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(unlock(x))
 
 // An escape hatch for thread safety analysis to ignore the annotated function.
-#define NO_THREAD_SAFETY_ANALYSIS  __attribute__ ((no_thread_safety_analysis))
+#define NO_THREAD_SAFETY_ANALYSIS \
+  THREAD_ANNOTATION_ATTRIBUTE__(no_thread_safety_analysis)
 
-
-#else
-
-// When the compiler is not GCC, these annotations are simply no-ops.
-
-// NOTE: in theory, the macros that take "arg" below *could* take
-// multiple arguments, but in practice so far they only take one.
-// Since not all non-gcc compilers support ... -- notably MSVC 7.1 --
-// I just hard-code in a single arg.  If this assumption ever breaks,
-// we can change it back to "...", or handle it some other way.
-
-#define GUARDED_BY(x)                   // no-op
-#define GUARDED_VAR                     // no-op
-#define PT_GUARDED_BY(x)                // no-op
-#define PT_GUARDED_VAR                  // no-op
-#define ACQUIRED_AFTER(arg)             // no-op
-#define ACQUIRED_BEFORE(arg)            // no-op
-#define EXCLUSIVE_LOCKS_REQUIRED(arg)   // no-op
-#define SHARED_LOCKS_REQUIRED(arg)      // no-op
-#define LOCKS_EXCLUDED(arg)             // no-op
-#define LOCK_RETURNED(x)                // no-op
-#define LOCKABLE                        // no-op
-#define SCOPED_LOCKABLE                 // no-op
-#define EXCLUSIVE_LOCK_FUNCTION(arg)    // no-op
-#define SHARED_LOCK_FUNCTION(arg)       // no-op
-#define EXCLUSIVE_TRYLOCK_FUNCTION(arg) // no-op
-#define SHARED_TRYLOCK_FUNCTION(arg)    // no-op
-#define UNLOCK_FUNCTION(arg)            // no-op
-#define NO_THREAD_SAFETY_ANALYSIS       // no-op
-
-#endif // defined(__GNUC__) && defined(__SUPPORT_TS_ANNOTATION__)
-       // && !defined(SWIG)
-
 #endif  // BASE_THREAD_ANNOTATIONS_H_