diff -r 000000000000 -r 6474c204b198 js/src/frontend/ParseMaps.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/frontend/ParseMaps.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,136 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "frontend/ParseMaps-inl.h"
+
+#include "jscntxt.h"
+
+#include "frontend/FullParseHandler.h"
+#include "frontend/SyntaxParseHandler.h"
+
+using namespace js;
+using namespace js::frontend;
+
+void
+ParseMapPool::checkInvariants()
+{
+    /*
+     * Having all values be of the same size permits us to easily reuse the
+     * allocated space for each of the map types.
+     */
+    JS_STATIC_ASSERT(sizeof(Definition *) == sizeof(jsatomid));
+    JS_STATIC_ASSERT(sizeof(Definition *) == sizeof(DefinitionList));
+    JS_STATIC_ASSERT(sizeof(AtomDefnMap::Entry) == sizeof(AtomIndexMap::Entry));
+    JS_STATIC_ASSERT(sizeof(AtomDefnMap::Entry) == sizeof(AtomDefnListMap::Entry));
+    JS_STATIC_ASSERT(sizeof(AtomMapT::Entry) == sizeof(AtomDefnListMap::Entry));
+    /* Ensure that the HasTable::clear goes quickly via memset. */
+    JS_STATIC_ASSERT(mozilla::IsPod<AtomIndexMap::WordMap::Entry>::value);
+    JS_STATIC_ASSERT(mozilla::IsPod<AtomDefnListMap::WordMap::Entry>::value);
+    JS_STATIC_ASSERT(mozilla::IsPod<AtomDefnMap::WordMap::Entry>::value);
+}
+
+void
+ParseMapPool::purgeAll()
+{
+    for (void **it = all.begin(), **end = all.end(); it != end; ++it)
+        js_delete<AtomMapT>(asAtomMap(*it));
+
+    all.clearAndFree();
+    recyclable.clearAndFree();
+}
+
+void *
+ParseMapPool::allocateFresh()
+{
+    size_t newAllLength = all.length() + 1;
+    if (!all.reserve(newAllLength) || !recyclable.reserve(newAllLength))
+        return nullptr;
+
+    AtomMapT *map = js_new<AtomMapT>();
+    if (!map)
+        return nullptr;
+
+    all.infallibleAppend(map);
+    return (void *) map;
+}
+
+DefinitionList::Node *
+DefinitionList::allocNode(ExclusiveContext *cx, LifoAlloc &alloc, uintptr_t head, Node *tail)
+{
+    Node *result = alloc.new_<Node>(head, tail);
+    if (!result)
+        js_ReportOutOfMemory(cx);
+    return result;
+}
+
+#ifdef DEBUG
+template <typename ParseHandler>
+void
+AtomDecls<ParseHandler>::dump()
+{
+    for (AtomDefnListRange r = map->all(); !r.empty(); r.popFront()) {
+        fprintf(stderr, "atom: ");
+        js_DumpAtom(r.front().key());
+        const DefinitionList &dlist = r.front().value();
+        for (DefinitionList::Range dr = dlist.all(); !dr.empty(); dr.popFront()) {
+            fprintf(stderr, "    defn: %p\n", (void *) dr.front<ParseHandler>());
+        }
+    }
+}
+
+void
+DumpAtomDefnMap(const AtomDefnMapPtr &map)
+{
+    if (map->empty()) {
+        fprintf(stderr, "empty\n");
+        return;
+    }
+
+    for (AtomDefnRange r = map->all(); !r.empty(); r.popFront()) {
+        fprintf(stderr, "atom: ");
+        js_DumpAtom(r.front().key());
+        fprintf(stderr, "defn: %p\n", (void *) r.front().value().get<FullParseHandler>());
+    }
+}
+#endif
+
+template <typename ParseHandler>
+bool
+AtomDecls<ParseHandler>::addShadow(JSAtom *atom, typename ParseHandler::DefinitionNode defn)
+{
+    AtomDefnListAddPtr p = map->lookupForAdd(atom);
+    if (!p)
+        return map->add(p, atom, DefinitionList(ParseHandler::definitionToBits(defn)));
+
+    return p.value().pushFront<ParseHandler>(cx, alloc, defn);
+}
+
+void
+frontend::InitAtomMap(frontend::AtomIndexMap *indices, HeapPtrAtom *atoms)
+{
+    if (indices->isMap()) {
+        typedef AtomIndexMap::WordMap WordMap;
+        const WordMap &wm = indices->asMap();
+        for (WordMap::Range r = wm.all(); !r.empty(); r.popFront()) {
+            JSAtom *atom = r.front().key();
+            jsatomid index = r.front().value();
+            JS_ASSERT(index < indices->count());
+            atoms[index].init(atom);
+        }
+    } else {
+        for (const AtomIndexMap::InlineElem *it = indices->asInline(), *end = indices->inlineEnd();
+             it != end; ++it) {
+            JSAtom *atom = it->key;
+            if (!atom)
+                continue;
+            JS_ASSERT(it->value < indices->count());
+            atoms[it->value].init(atom);
+        }
+    }
+}
+
+template class js::frontend::AtomDecls<FullParseHandler>;
+template class js::frontend::AtomDecls<SyntaxParseHandler>;