Bug 703833 - Add an uintptr_t alternative to the jsval payload, and use it for MarkStackRangeConservatively. r=luke

js/src/jsapi.h

@@ -572,6 +572,14 @@ class Value
 #endif
     }
 
+    const uintptr_t *payloadUIntPtr() const {
+#if JS_BITS_PER_WORD == 32
+        return &data.s.payload.uintptr;
+#elif JS_BITS_PER_WORD == 64
+        return &data.asUIntPtr;
+#endif
+    }
+
 #if !defined(_MSC_VER) && !defined(__sparc)
   /* To make jsval binary compatible when linking across C and C++ with MSVC,
    * JS::Value needs to be POD. Otherwise, jsval will be passed in memory

js/src/jsgc.cpp

@@ -1109,8 +1109,8 @@ MarkConservativeStackRoots(JSTracer *trc, bool useSavedRoots)
 void
 MarkStackRangeConservatively(JSTracer *trc, Value *beginv, Value *endv)
 {
-    const uintptr_t *begin = beginv->payloadWord();
-    const uintptr_t *end = endv->payloadWord();
+    const uintptr_t *begin = beginv->payloadUIntPtr();
+    const uintptr_t *end = endv->payloadUIntPtr();
 #ifdef JS_NUNBOX32
     /*
      * With 64-bit jsvals on 32-bit systems, we can optimize a bit by

js/src/jsval.h

@@ -237,6 +237,7 @@ typedef union jsval_layout
             void           *ptr;
             JSWhyMagic     why;
             size_t         word;
+            uintptr_t      uintptr;
         } payload;
         JSValueTag tag;
     } s;
@@ -264,6 +265,7 @@ typedef union jsval_layout
     double asDouble;
     void *asPtr;
     size_t asWord;
+    uintptr_t asUIntPtr;
 } JSVAL_ALIGNMENT jsval_layout;
 # endif  /* JS_BITS_PER_WORD */
 #else   /* defined(IS_LITTLE_ENDIAN) */
@@ -282,6 +284,7 @@ typedef union jsval_layout
             void           *ptr;
             JSWhyMagic     why;
             size_t         word;
+            uintptr_t      uintptr;
         } payload;
     } s;
     double asDouble;
@@ -306,6 +309,7 @@ typedef union jsval_layout
     double asDouble;
     void *asPtr;
     size_t asWord;
+    uintptr_t asUIntPtr;
 } JSVAL_ALIGNMENT jsval_layout;
 # endif /* JS_BITS_PER_WORD */
 #endif  /* defined(IS_LITTLE_ENDIAN) */