Bug 694256 - Build error: JS_FloorLog2 is missing. r=luke.

js/public/Utility.h

@@ -346,7 +346,7 @@ __BitScanReverse64(unsigned __int64 val)
 #  define js_FloorLog2wImpl(n)                                                \
     ((size_t)(JS_BITS_PER_WORD - 1 - js_bitscan_clz32(n)))
 # else
-#  define js_FloorLog2wImpl(n) ((size_t)JS_FloorLog2(n))
+extern size_t js_FloorLog2wImpl(size_t n);
 # endif
 #elif JS_BYTES_PER_WORD == 8
 # ifdef JS_HAS_BUILTIN_BITSCAN64

js/src/jslog2.cpp

@@ -54,6 +54,17 @@ JS_STATIC_ASSERT_IF(JS_BYTES_PER_WORD == 8,
                     sizeof(unsigned long long) == sizeof(JSUword));
 #endif
 
+#if !defined(JS_HAS_BUILTIN_BITSCAN32) && JS_BYTES_PER_WORD == 4
+
+size_t
+js_FloorLog2wImpl(size_t n)
+{
+    size_t log2;
+
+    JS_FLOOR_LOG2(log2, n);
+    return log2;
+}
+#endif
 /*
  * js_FloorLog2wImpl has to be defined only for 64-bit non-GCC case.
  */