Bug 1125185 - Define MOZ_COLD for marking "cold" functions r=waldo

js/public/Utility.h

@@ -53,7 +53,7 @@ namespace js {}
 #define JS_STATIC_ASSERT(cond)           static_assert(cond, "JS_STATIC_ASSERT")
 #define JS_STATIC_ASSERT_IF(cond, expr)  MOZ_STATIC_ASSERT_IF(cond, expr, "JS_STATIC_ASSERT_IF")
 
-extern MOZ_NORETURN JS_PUBLIC_API(void)
+extern MOZ_NORETURN MOZ_COLD JS_PUBLIC_API(void)
 JS_Assert(const char *s, const char *file, int ln);
 
 /*

js/src/ds/LifoAlloc.h

@@ -148,9 +148,6 @@ class BumpChunk
 
 } // namespace detail
 
-MOZ_NORETURN void
-CrashAtUnhandlableOOM(const char *reason);
-
 // LIFO bump allocator: used for phase-oriented and fast LIFO allocations.
 //
 // Note: |latest| is not necessary "last". We leave BumpChunks latent in the

js/src/gc/StoreBuffer.h

@@ -19,10 +19,6 @@
 #include "js/MemoryMetrics.h"
 
 namespace js {
-
-MOZ_NORETURN void
-CrashAtUnhandlableOOM(const char *reason);
-
 namespace gc {
 
 /*

js/src/jsinfer.h

@@ -1773,7 +1773,7 @@ inline const char * TypeObjectString(TypeObject *type) { return nullptr; }
 #endif
 
 /* Print a warning, dump state and abort the program. */
-MOZ_NORETURN void TypeFailure(JSContext *cx, const char *fmt, ...);
+MOZ_NORETURN MOZ_COLD void TypeFailure(JSContext *cx, const char *fmt, ...);
 
 } /* namespace types */
 } /* namespace js */

js/src/jsutil.cpp

@@ -50,7 +50,7 @@ namespace js {
 // This function calls all the vanilla heap allocation functions.  It is never
 // called, and exists purely to help config/check_vanilla_allocations.py.  See
 // that script for more details.
-extern void
+extern MOZ_COLD void
 AllTheNonBasicVanillaNewAllocations()
 {
     // posix_memalign and aligned_alloc aren't available on all Linux

js/src/jsutil.h

@@ -43,6 +43,9 @@ js_memcpy(void *dst_, const void *src_, size_t len)
 
 namespace js {
 
+MOZ_NORETURN MOZ_COLD void
+CrashAtUnhandlableOOM(const char *reason);
+
 template <class T>
 struct AlignmentTestStruct
 {

js/src/vm/Runtime.h

@@ -63,13 +63,13 @@ extern mozilla::ThreadLocal<PerThreadData*> TlsPerThreadData;
 
 struct DtoaState;
 
-extern void
+extern MOZ_COLD void
 js_ReportOutOfMemory(js::ExclusiveContext *cx);
 
-extern void
+extern MOZ_COLD void
 js_ReportAllocationOverflow(js::ExclusiveContext *maybecx);
 
-extern void
+extern MOZ_COLD void
 js_ReportOverRecursed(js::ExclusiveContext *cx);
 
 namespace js {

mfbt/Assertions.h

@@ -131,7 +131,7 @@ extern "C" {
  * method is primarily for internal use in this header, and only secondarily
  * for use in implementing release-build assertions.
  */
-static MOZ_ALWAYS_INLINE void
+static MOZ_COLD MOZ_ALWAYS_INLINE void
 MOZ_ReportAssertionFailure(const char* aStr, const char* aFilename, int aLine)
   MOZ_PRETEND_NORETURN_FOR_STATIC_ANALYSIS
 {
@@ -148,7 +148,7 @@ MOZ_ReportAssertionFailure(const char* aStr, const char* aFilename, int aLine)
 #endif
 }
 
-static MOZ_ALWAYS_INLINE void
+static MOZ_COLD MOZ_ALWAYS_INLINE void
 MOZ_ReportCrash(const char* aStr, const char* aFilename, int aLine)
   MOZ_PRETEND_NORETURN_FOR_STATIC_ANALYSIS
 {

mfbt/Attributes.h

@@ -191,6 +191,27 @@
 #  define MOZ_NORETURN          /* no support */
 #endif
 
+/**
+ * MOZ_COLD tells the compiler that a function is "cold", meaning infrequently
+ * executed. This may lead it to optimize for size more aggressively than speed,
+ * or to allocate the body of the function in a distant part of the text segment
+ * to help keep it from taking up unnecessary icache when it isn't in use.
+ *
+ * Place this attribute at the very beginning of a function definition. For
+ * example, write
+ *
+ *   MOZ_COLD int foo();
+ *
+ * or
+ *
+ *   MOZ_COLD int foo() { return 42; }
+ */
+#if defined(__GNUC__) || defined(__clang__)
+#  define MOZ_COLD __attribute__ ((cold))
+#else
+#  define MOZ_COLD
+#endif
+
 /*
  * MOZ_PRETEND_NORETURN_FOR_STATIC_ANALYSIS, specified at the end of a function
  * declaration, indicates that for the purposes of static analysis, this