Bug 1347489 - Give StringSegmentRange stack Vector some inline capacity to avoid malloc/free overhead. r=luke

--HG--
extra : rebase_source : 6ad96563e57af30665ac82bb75bb02b4a4d8a91f

js/src/jsstr.cpp

@@ -1460,7 +1460,8 @@ class StringSegmentRange
 {
     // If malloc() shows up in any profiles from this vector, we can add a new
     // StackAllocPolicy which stashes a reusable freed-at-gc buffer in the cx.
-    Rooted<StringVector> stack;
+    using StackVector = JS::GCVector<JSString*, 16>;
+    Rooted<StackVector> stack;
     RootedLinearString cur;
 
     bool settle(JSString* str) {
@@ -1476,7 +1477,7 @@ class StringSegmentRange
 
   public:
     explicit StringSegmentRange(JSContext* cx)
-      : stack(cx, StringVector(cx)), cur(cx)
+      : stack(cx, StackVector(cx)), cur(cx)
     {}
 
     MOZ_MUST_USE bool init(JSString* str) {