import changes from `dev' branch of rmottola/Arctic-Fox:

- more pointer style... take away, put again... (640edf447)
- Bug 1139683 - Rewrite SetExistingProperty with comments and references to the standard. r=efaust. (0da1e634b)
- Bug 1142775 - Rename NativeSet -> NativeSetExistingDataProperty and simplify it since it is only called for data properties. Delete Shape::set. Add comments. No change in behavior. r=efaust. (1fec7be0a)
- Bug 1142794 - Change 'receiver' argument to SetProperty functions and ProxyHandler::set methods to be a HandleValue. r=Waldo. (032f78c22)
- Bug 1149377 - Disable PGO on ICCallStubCompiler::guardFunApply. r=jandem (aa0617c41)
- Revert Bug 1137180 - Allow unboxed objects to be extended with new properties, r=jandem. (1970f92f0)
- Bug 1137180 - Add most functionality necessary for extensible unboxed objects, r=jandem. (30768aa93)
- Bug 1137180 - Add baseline caches for extensible unboxed objects, and enable extensible unboxed objects (still off by default), r=jandem. (8c6aa02f9)
- Bug 1143011 - Extract the has/add/take logic out of the register sets to distinguish between allocatable and live sets. r=jandem,Waldo (430b0830f)
- Bug 1143011 - Use AllocatableSet or LiveSet for all register set uses. r=jandem (69dc22ad9)
- Bug 1150384 - IonMonkey: MIPS: Fix build failure caused by Bug 1143011. r=rankov (f532d5095)
- Bug 1145811 - Remove simdSet argument of PushRegsInMask. r=bbouvier (7c1dd4847)
- Bug 1148880 - Make Trampoline-arm.cpp compile with Clang again. r=nbp (b89564285)
- Bump the XDR version two more to account for yet more branch-versioning oddities. No bug, r=me as trivial, DONTBUILD because really building bytecode-bumping patchwork twice is just too much for an opaque identifier that we already built once, pushing in a CLOSED TREE because version bumps are risk-free and these versions are needed for a branch backport and otherwise I'm spinning wheels waiting on the tree to reopen right now (ab7ac9762)
- partial of Bug 1144366 - Switch SpiderMonkey and XPConnect style from |T *t| to |T* t|. r=jorendorff (9e27b1ba4)
- Bug 1134626 part 1 - Move all x86-shared files into their own directory. r=jandem (6267cdb05)
- Bug 1134626 part 2 - Move x86 & x64 Architecture into a shared file. r=jandem (467731dfc)

js/src/jsarray.cpp

@@ -364,8 +364,7 @@ SetArrayElement(JSContext* cx, HandleObject obj, double index, HandleValue v)
     if (!ToId(cx, index, &id))
         return false;
 
-    RootedValue tmp(cx, v);
-    return SetProperty(cx, obj, obj, id, &tmp);
+    return SetProperty(cx, obj, id, v);
 }
 
 /*
@@ -434,7 +433,7 @@ bool
 js::SetLengthProperty(JSContext* cx, HandleObject obj, double length)
 {
     RootedValue v(cx, NumberValue(length));
-    return SetProperty(cx, obj, obj, cx->names().length, &v);
+    return SetProperty(cx, obj, cx->names().length, v);
 }
 
 /*
@@ -1270,11 +1269,10 @@ InitArrayElements(JSContext *cx, HandleObject obj, uint32_t start, uint32_t coun
     do {
         value = *vector++;
         indexv = DoubleValue(index);
-        if (!ValueToId<CanGC>(cx, indexv, &id) ||
-            !SetProperty(cx, obj, obj, id, &value))
-        {
+        if (!ValueToId<CanGC>(cx, indexv, &id))
+            return false;
+        if (!SetProperty(cx, obj, id, value))
             return false;
-        }
         index += 1;
     } while (vector != end);