# HG changeset patch
# User Jeff Walden <jwalden@mit.edu>
# Date 1323815468 18000
# Node ID 561838b84f73accc6a845afaa1b64782bfca6a12
# Parent  850c7301c926392e28f2093d06e2ea1b4754853f
Silence unused-value warnings with various Valgrind macros in clang, and add a silencing instance to jsgc.cpp.  No bug, rs=jorendorff

diff --git a/js/src/jsdbgapi.cpp b/js/src/jsdbgapi.cpp
--- a/js/src/jsdbgapi.cpp
+++ b/js/src/jsdbgapi.cpp
@@ -1490,36 +1490,18 @@ JS_DefineProfilingFunctions(JSContext *c
 
 #include <valgrind/callgrind.h>
 
-/*
- * Wrapper for callgrind macros to stop warnings coming from their expansions.
- */ 
-#if (__GNUC__ >= 5) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
-# define WRAP_CALLGRIND(call)                                                 \
-    JS_BEGIN_MACRO                                                            \
-        _Pragma("GCC diagnostic push")                                        \
-        _Pragma("GCC diagnostic ignored \"-Wunused-but-set-variable\"")       \
-        call;                                                                 \
-        _Pragma("GCC diagnostic pop")                                         \
-    JS_END_MACRO
-#else
-# define WRAP_CALLGRIND(call)                                                 \
-    JS_BEGIN_MACRO                                                            \
-        call;                                                                 \
-    JS_END_MACRO
-#endif
-
 JS_FRIEND_API(JSBool)
 js_StartCallgrind()
 {
-    WRAP_CALLGRIND(CALLGRIND_START_INSTRUMENTATION);
-    WRAP_CALLGRIND(CALLGRIND_ZERO_STATS);
+    JS_SILENCE_UNUSED_VALUE_IN_EXPR(CALLGRIND_START_INSTRUMENTATION);
+    JS_SILENCE_UNUSED_VALUE_IN_EXPR(CALLGRIND_ZERO_STATS);
     return true;
 }
 
 JS_FRIEND_API(JSBool)
 js_StopCallgrind()
 {
-    WRAP_CALLGRIND(CALLGRIND_STOP_INSTRUMENTATION);
+    JS_SILENCE_UNUSED_VALUE_IN_EXPR(CALLGRIND_STOP_INSTRUMENTATION);
     return true;
 }
 
@@ -1527,9 +1509,9 @@ JS_FRIEND_API(JSBool)
 js_DumpCallgrind(const char *outfile)
 {
     if (outfile) {
-        WRAP_CALLGRIND(CALLGRIND_DUMP_STATS_AT(outfile));
+        JS_SILENCE_UNUSED_VALUE_IN_EXPR(CALLGRIND_DUMP_STATS_AT(outfile));
     } else {
-        WRAP_CALLGRIND(CALLGRIND_DUMP_STATS);
+        JS_SILENCE_UNUSED_VALUE_IN_EXPR(CALLGRIND_DUMP_STATS);
     }
 
     return true;
diff --git a/js/src/jsgc.cpp b/js/src/jsgc.cpp
--- a/js/src/jsgc.cpp
+++ b/js/src/jsgc.cpp
@@ -1010,7 +1010,7 @@ MarkWordConservatively(JSTracer *trc, js
      * original word. See bug 572678.
      */
 #ifdef JS_VALGRIND
-    VALGRIND_MAKE_MEM_DEFINED(&w, sizeof(w));
+    JS_SILENCE_UNUSED_VALUE_IN_EXPR(VALGRIND_MAKE_MEM_DEFINED(&w, sizeof(w)));
 #endif
 
     MarkIfGCThingWord(trc, w);
diff --git a/js/src/jsutil.h b/js/src/jsutil.h
--- a/js/src/jsutil.h
+++ b/js/src/jsutil.h
@@ -440,4 +440,28 @@ typedef size_t jsbitmap;
 #define JS_CLEAR_BIT(_map,_bit) ((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] &=     \
                                  ~((jsbitmap)1<<((_bit)&(JS_BITS_PER_WORD-1))))
 
+/* Wrapper for various macros to stop warnings coming from their expansions. */
+#if defined(__clang__)
+# define JS_SILENCE_UNUSED_VALUE_IN_EXPR(expr)                                \
+    JS_BEGIN_MACRO                                                            \
+        _Pragma("clang diagnostic push")                                      \
+        _Pragma("clang diagnostic ignored \"-Wunused-value\"")                \
+        expr;                                                                 \
+        _Pragma("clang diagnostic pop")                                       \
+    JS_END_MACRO
+#elif (__GNUC__ >= 5) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
+# define JS_SILENCE_UNUSED_VALUE_IN_EXPR(expr)                                \
+    JS_BEGIN_MACRO                                                            \
+        _Pragma("GCC diagnostic push")                                        \
+        _Pragma("GCC diagnostic ignored \"-Wunused-but-set-variable\"")       \
+        expr;                                                                 \
+        _Pragma("GCC diagnostic pop")                                         \
+    JS_END_MACRO
+#else
+# define JS_SILENCE_UNUSED_VALUE_IN_EXPR(expr)                                \
+    JS_BEGIN_MACRO                                                            \
+        expr;                                                                 \
+    JS_END_MACRO
+#endif
+
 #endif /* jsutil_h___ */