diff -r 000000000000 -r 6474c204b198 js/src/jsatom.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jsatom.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,606 @@
+/* -*- 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/. */
+
+/*
+ * JS atom table.
+ */
+
+#include "jsatominlines.h"
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/RangedPtr.h"
+
+#include <string.h>
+
+#include "jscntxt.h"
+#include "jsstr.h"
+#include "jstypes.h"
+
+#include "gc/Marking.h"
+#include "vm/Xdr.h"
+
+#include "jscntxtinlines.h"
+#include "jscompartmentinlines.h"
+#include "jsobjinlines.h"
+
+#include "vm/String-inl.h"
+
+using namespace js;
+using namespace js::gc;
+
+using mozilla::ArrayEnd;
+using mozilla::ArrayLength;
+using mozilla::RangedPtr;
+
+const char *
+js::AtomToPrintableString(ExclusiveContext *cx, JSAtom *atom, JSAutoByteString *bytes)
+{
+    JSString *str = js_QuoteString(cx, atom, 0);
+    if (!str)
+        return nullptr;
+    return bytes->encodeLatin1(cx, str);
+}
+
+const char * const js::TypeStrings[] = {
+    js_undefined_str,
+    js_object_str,
+    js_function_str,
+    js_string_str,
+    js_number_str,
+    js_boolean_str,
+    js_null_str,
+};
+
+#define DEFINE_PROTO_STRING(name,code,init,clasp) const char js_##name##_str[] = #name;
+JS_FOR_EACH_PROTOTYPE(DEFINE_PROTO_STRING)
+#undef DEFINE_PROTO_STRING
+
+#define CONST_CHAR_STR(idpart, id, text) const char js_##idpart##_str[] = text;
+FOR_EACH_COMMON_PROPERTYNAME(CONST_CHAR_STR)
+#undef CONST_CHAR_STR
+
+/* Constant strings that are not atomized. */
+const char js_break_str[]           = "break";
+const char js_case_str[]            = "case";
+const char js_catch_str[]           = "catch";
+const char js_class_str[]           = "class";
+const char js_close_str[]           = "close";
+const char js_const_str[]           = "const";
+const char js_continue_str[]        = "continue";
+const char js_debugger_str[]        = "debugger";
+const char js_default_str[]         = "default";
+const char js_do_str[]              = "do";
+const char js_else_str[]            = "else";
+const char js_enum_str[]            = "enum";
+const char js_export_str[]          = "export";
+const char js_extends_str[]         = "extends";
+const char js_finally_str[]         = "finally";
+const char js_for_str[]             = "for";
+const char js_getter_str[]          = "getter";
+const char js_if_str[]              = "if";
+const char js_implements_str[]      = "implements";
+const char js_import_str[]          = "import";
+const char js_in_str[]              = "in";
+const char js_instanceof_str[]      = "instanceof";
+const char js_interface_str[]       = "interface";
+const char js_new_str[]             = "new";
+const char js_package_str[]         = "package";
+const char js_private_str[]         = "private";
+const char js_protected_str[]       = "protected";
+const char js_public_str[]          = "public";
+const char js_send_str[]            = "send";
+const char js_setter_str[]          = "setter";
+const char js_static_str[]          = "static";
+const char js_super_str[]           = "super";
+const char js_switch_str[]          = "switch";
+const char js_this_str[]            = "this";
+const char js_try_str[]             = "try";
+const char js_typeof_str[]          = "typeof";
+const char js_void_str[]            = "void";
+const char js_while_str[]           = "while";
+const char js_with_str[]            = "with";
+
+// Use a low initial capacity for atom hash tables to avoid penalizing runtimes
+// which create a small number of atoms.
+static const uint32_t JS_STRING_HASH_COUNT = 64;
+
+struct CommonNameInfo
+{
+    const char *str;
+    size_t length;
+};
+
+bool
+JSRuntime::initializeAtoms(JSContext *cx)
+{
+    atoms_ = cx->new_<AtomSet>();
+    if (!atoms_ || !atoms_->init(JS_STRING_HASH_COUNT))
+        return false;
+
+    if (parentRuntime) {
+        staticStrings = parentRuntime->staticStrings;
+        commonNames = parentRuntime->commonNames;
+        emptyString = parentRuntime->emptyString;
+        permanentAtoms = parentRuntime->permanentAtoms;
+        return true;
+    }
+
+    permanentAtoms = cx->new_<AtomSet>();
+    if (!permanentAtoms || !permanentAtoms->init(JS_STRING_HASH_COUNT))
+        return false;
+
+    staticStrings = cx->new_<StaticStrings>();
+    if (!staticStrings || !staticStrings->init(cx))
+        return false;
+
+    static const CommonNameInfo cachedNames[] = {
+#define COMMON_NAME_INFO(idpart, id, text) { js_##idpart##_str, sizeof(text) - 1 },
+        FOR_EACH_COMMON_PROPERTYNAME(COMMON_NAME_INFO)
+#undef COMMON_NAME_INFO
+#define COMMON_NAME_INFO(name, code, init, clasp) { js_##name##_str, sizeof(#name) - 1 },
+        JS_FOR_EACH_PROTOTYPE(COMMON_NAME_INFO)
+#undef COMMON_NAME_INFO
+    };
+
+    commonNames = cx->new_<JSAtomState>();
+    if (!commonNames)
+        return false;
+
+    FixedHeapPtr<PropertyName> *names = reinterpret_cast<FixedHeapPtr<PropertyName> *>(commonNames);
+    for (size_t i = 0; i < ArrayLength(cachedNames); i++, names++) {
+        JSAtom *atom = Atomize(cx, cachedNames[i].str, cachedNames[i].length, InternAtom);
+        if (!atom)
+            return false;
+        names->init(atom->asPropertyName());
+    }
+    JS_ASSERT(uintptr_t(names) == uintptr_t(commonNames + 1));
+
+    emptyString = commonNames->empty;
+    return true;
+}
+
+void
+JSRuntime::finishAtoms()
+{
+    if (atoms_)
+        js_delete(atoms_);
+
+    if (!parentRuntime) {
+        if (staticStrings)
+            js_delete(staticStrings);
+
+        if (commonNames)
+            js_delete(commonNames);
+
+        if (permanentAtoms)
+            js_delete(permanentAtoms);
+    }
+
+    atoms_ = nullptr;
+    staticStrings = nullptr;
+    commonNames = nullptr;
+    permanentAtoms = nullptr;
+    emptyString = nullptr;
+}
+
+void
+js::MarkAtoms(JSTracer *trc)
+{
+    JSRuntime *rt = trc->runtime();
+    for (AtomSet::Enum e(rt->atoms()); !e.empty(); e.popFront()) {
+        const AtomStateEntry &entry = e.front();
+        if (!entry.isTagged())
+            continue;
+
+        JSAtom *atom = entry.asPtr();
+        bool tagged = entry.isTagged();
+        MarkStringRoot(trc, &atom, "interned_atom");
+        if (entry.asPtr() != atom)
+            e.rekeyFront(AtomHasher::Lookup(atom), AtomStateEntry(atom, tagged));
+    }
+}
+
+void
+js::MarkPermanentAtoms(JSTracer *trc)
+{
+    JSRuntime *rt = trc->runtime();
+
+    // Permanent atoms only need to be marked in the runtime which owns them.
+    if (rt->parentRuntime)
+        return;
+
+    // Static strings are not included in the permanent atoms table.
+    if (rt->staticStrings)
+        rt->staticStrings->trace(trc);
+
+    if (rt->permanentAtoms) {
+        for (AtomSet::Enum e(*rt->permanentAtoms); !e.empty(); e.popFront()) {
+            const AtomStateEntry &entry = e.front();
+
+            JSAtom *atom = entry.asPtr();
+            MarkPermanentAtom(trc, atom, "permanent_table");
+        }
+    }
+}
+
+void
+JSRuntime::sweepAtoms()
+{
+    if (!atoms_)
+        return;
+
+    for (AtomSet::Enum e(*atoms_); !e.empty(); e.popFront()) {
+        AtomStateEntry entry = e.front();
+        JSAtom *atom = entry.asPtr();
+        bool isDying = IsStringAboutToBeFinalized(&atom);
+
+        /* Pinned or interned key cannot be finalized. */
+        JS_ASSERT_IF(hasContexts() && entry.isTagged(), !isDying);
+
+        if (isDying)
+            e.removeFront();
+    }
+}
+
+bool
+JSRuntime::transformToPermanentAtoms()
+{
+    JS_ASSERT(!parentRuntime);
+
+    // All static strings were created as permanent atoms, now move the contents
+    // of the atoms table into permanentAtoms and mark each as permanent.
+
+    JS_ASSERT(permanentAtoms && permanentAtoms->empty());
+
+    AtomSet *temp = atoms_;
+    atoms_ = permanentAtoms;
+    permanentAtoms = temp;
+
+    for (AtomSet::Enum e(*permanentAtoms); !e.empty(); e.popFront()) {
+        AtomStateEntry entry = e.front();
+        JSAtom *atom = entry.asPtr();
+        atom->morphIntoPermanentAtom();
+    }
+
+    return true;
+}
+
+bool
+AtomIsInterned(JSContext *cx, JSAtom *atom)
+{
+    /* We treat static strings as interned because they're never collected. */
+    if (StaticStrings::isStatic(atom))
+        return true;
+
+    AtomHasher::Lookup lookup(atom);
+
+    /* Likewise, permanent strings are considered to be interned. */
+    AtomSet::Ptr p = cx->permanentAtoms().readonlyThreadsafeLookup(lookup);
+    if (p)
+        return true;
+
+    AutoLockForExclusiveAccess lock(cx);
+
+    p = cx->runtime()->atoms().lookup(lookup);
+    if (!p)
+        return false;
+
+    return p->isTagged();
+}
+
+/*
+ * When the jschars reside in a freshly allocated buffer the memory can be used
+ * as a new JSAtom's storage without copying. The contract is that the caller no
+ * longer owns the memory and this method is responsible for freeing the memory.
+ */
+MOZ_ALWAYS_INLINE
+static JSAtom *
+AtomizeAndtake(ExclusiveContext *cx, jschar *tbchars, size_t length, InternBehavior ib)
+{
+    JS_ASSERT(tbchars[length] == 0);
+
+    if (JSAtom *s = cx->staticStrings().lookup(tbchars, length)) {
+        js_free(tbchars);
+        return s;
+    }
+
+    AtomHasher::Lookup lookup(tbchars, length);
+
+    AtomSet::Ptr pp = cx->permanentAtoms().readonlyThreadsafeLookup(lookup);
+    if (pp) {
+        js_free(tbchars);
+        return pp->asPtr();
+    }
+
+    AutoLockForExclusiveAccess lock(cx);
+
+    /*
+     * If a GC occurs at js_NewStringCopy then |p| will still have the correct
+     * hash, allowing us to avoid rehashing it. Even though the hash is
+     * unchanged, we need to re-lookup the table position because a last-ditch
+     * GC will potentially free some table entries.
+     */
+    AtomSet& atoms = cx->atoms();
+    AtomSet::AddPtr p = atoms.lookupForAdd(lookup);
+    if (p) {
+        JSAtom *atom = p->asPtr();
+        p->setTagged(bool(ib));
+        js_free(tbchars);
+        return atom;
+    }
+
+    AutoCompartment ac(cx, cx->atomsCompartment());
+
+    JSFlatString *flat = js_NewString<NoGC>(cx, tbchars, length);
+    if (!flat) {
+        js_free(tbchars);
+        js_ReportOutOfMemory(cx);
+        return nullptr;
+    }
+
+    JSAtom *atom = flat->morphAtomizedStringIntoAtom();
+
+    if (!atoms.relookupOrAdd(p, lookup, AtomStateEntry(atom, bool(ib)))) {
+        js_ReportOutOfMemory(cx); /* SystemAllocPolicy does not report OOM. */
+        return nullptr;
+    }
+
+    return atom;
+}
+
+/* |tbchars| must not point into an inline or short string. */
+MOZ_ALWAYS_INLINE
+static JSAtom *
+AtomizeAndCopyChars(ExclusiveContext *cx, const jschar *tbchars, size_t length, InternBehavior ib)
+{
+    if (JSAtom *s = cx->staticStrings().lookup(tbchars, length))
+         return s;
+
+    AtomHasher::Lookup lookup(tbchars, length);
+
+    AtomSet::Ptr pp = cx->permanentAtoms().readonlyThreadsafeLookup(lookup);
+    if (pp)
+        return pp->asPtr();
+
+    /*
+     * If a GC occurs at js_NewStringCopy then |p| will still have the correct
+     * hash, allowing us to avoid rehashing it. Even though the hash is
+     * unchanged, we need to re-lookup the table position because a last-ditch
+     * GC will potentially free some table entries.
+     */
+
+    AutoLockForExclusiveAccess lock(cx);
+
+    AtomSet& atoms = cx->atoms();
+    AtomSet::AddPtr p = atoms.lookupForAdd(lookup);
+    if (p) {
+        JSAtom *atom = p->asPtr();
+        p->setTagged(bool(ib));
+        return atom;
+    }
+
+    AutoCompartment ac(cx, cx->atomsCompartment());
+
+    JSFlatString *flat = js_NewStringCopyN<NoGC>(cx, tbchars, length);
+    if (!flat) {
+        js_ReportOutOfMemory(cx);
+        return nullptr;
+    }
+
+    JSAtom *atom = flat->morphAtomizedStringIntoAtom();
+
+    if (!atoms.relookupOrAdd(p, lookup, AtomStateEntry(atom, bool(ib)))) {
+        js_ReportOutOfMemory(cx); /* SystemAllocPolicy does not report OOM. */
+        return nullptr;
+    }
+
+    return atom;
+}
+
+JSAtom *
+js::AtomizeString(ExclusiveContext *cx, JSString *str,
+                  js::InternBehavior ib /* = js::DoNotInternAtom */)
+{
+    if (str->isAtom()) {
+        JSAtom &atom = str->asAtom();
+        /* N.B. static atoms are effectively always interned. */
+        if (ib != InternAtom || js::StaticStrings::isStatic(&atom))
+            return &atom;
+
+        AtomHasher::Lookup lookup(&atom);
+
+        /* Likewise, permanent atoms are always interned. */
+        AtomSet::Ptr p = cx->permanentAtoms().readonlyThreadsafeLookup(lookup);
+        if (p)
+            return &atom;
+
+        AutoLockForExclusiveAccess lock(cx);
+
+        p = cx->atoms().lookup(lookup);
+        JS_ASSERT(p); /* Non-static atom must exist in atom state set. */
+        JS_ASSERT(p->asPtr() == &atom);
+        JS_ASSERT(ib == InternAtom);
+        p->setTagged(bool(ib));
+        return &atom;
+    }
+
+    const jschar *chars = str->getChars(cx);
+    if (!chars)
+        return nullptr;
+
+    return AtomizeAndCopyChars(cx, chars, str->length(), ib);
+}
+
+JSAtom *
+js::Atomize(ExclusiveContext *cx, const char *bytes, size_t length, InternBehavior ib)
+{
+    CHECK_REQUEST(cx);
+
+    if (!JSString::validateLength(cx, length))
+        return nullptr;
+
+    static const unsigned ATOMIZE_BUF_MAX = 32;
+    if (length < ATOMIZE_BUF_MAX) {
+        /*
+         * Avoiding the malloc in InflateString on shorter strings saves us
+         * over 20,000 malloc calls on mozilla browser startup. This compares to
+         * only 131 calls where the string is longer than a 31 char (net) buffer.
+         * The vast majority of atomized strings are already in the hashtable. So
+         * js::AtomizeString rarely has to copy the temp string we make.
+         */
+        jschar inflated[ATOMIZE_BUF_MAX];
+        InflateStringToBuffer(bytes, length, inflated);
+        return AtomizeAndCopyChars(cx, inflated, length, ib);
+    }
+
+    jschar *tbcharsZ = InflateString(cx, bytes, &length);
+    if (!tbcharsZ)
+        return nullptr;
+    return AtomizeAndtake(cx, tbcharsZ, length, ib);
+}
+
+JSAtom *
+js::AtomizeChars(ExclusiveContext *cx, const jschar *chars, size_t length, InternBehavior ib)
+{
+    CHECK_REQUEST(cx);
+
+    if (!JSString::validateLength(cx, length))
+        return nullptr;
+
+    return AtomizeAndCopyChars(cx, chars, length, ib);
+}
+
+bool
+js::IndexToIdSlow(ExclusiveContext *cx, uint32_t index, MutableHandleId idp)
+{
+    JS_ASSERT(index > JSID_INT_MAX);
+
+    jschar buf[UINT32_CHAR_BUFFER_LENGTH];
+    RangedPtr<jschar> end(ArrayEnd(buf), buf, ArrayEnd(buf));
+    RangedPtr<jschar> start = BackfillIndexInCharBuffer(index, end);
+
+    JSAtom *atom = AtomizeChars(cx, start.get(), end - start);
+    if (!atom)
+        return false;
+
+    idp.set(JSID_FROM_BITS((size_t)atom));
+    return true;
+}
+
+template <AllowGC allowGC>
+static JSAtom *
+ToAtomSlow(ExclusiveContext *cx, typename MaybeRooted<Value, allowGC>::HandleType arg)
+{
+    JS_ASSERT(!arg.isString());
+
+    Value v = arg;
+    if (!v.isPrimitive()) {
+        if (!cx->shouldBeJSContext() || !allowGC)
+            return nullptr;
+        RootedValue v2(cx, v);
+        if (!ToPrimitive(cx->asJSContext(), JSTYPE_STRING, &v2))
+            return nullptr;
+        v = v2;
+    }
+
+    if (v.isString())
+        return AtomizeString(cx, v.toString());
+    if (v.isInt32())
+        return Int32ToAtom(cx, v.toInt32());
+    if (v.isDouble())
+        return NumberToAtom(cx, v.toDouble());
+    if (v.isBoolean())
+        return v.toBoolean() ? cx->names().true_ : cx->names().false_;
+    if (v.isNull())
+        return cx->names().null;
+    return cx->names().undefined;
+}
+
+template <AllowGC allowGC>
+JSAtom *
+js::ToAtom(ExclusiveContext *cx, typename MaybeRooted<Value, allowGC>::HandleType v)
+{
+    if (!v.isString())
+        return ToAtomSlow<allowGC>(cx, v);
+
+    JSString *str = v.toString();
+    if (str->isAtom())
+        return &str->asAtom();
+
+    return AtomizeString(cx, str);
+}
+
+template JSAtom *
+js::ToAtom<CanGC>(ExclusiveContext *cx, HandleValue v);
+
+template JSAtom *
+js::ToAtom<NoGC>(ExclusiveContext *cx, Value v);
+
+template<XDRMode mode>
+bool
+js::XDRAtom(XDRState<mode> *xdr, MutableHandleAtom atomp)
+{
+    if (mode == XDR_ENCODE) {
+        uint32_t nchars = atomp->length();
+        if (!xdr->codeUint32(&nchars))
+            return false;
+
+        jschar *chars = const_cast<jschar *>(atomp->getChars(xdr->cx()));
+        if (!chars)
+            return false;
+
+        return xdr->codeChars(chars, nchars);
+    }
+
+    /* Avoid JSString allocation for already existing atoms. See bug 321985. */
+    uint32_t nchars;
+    if (!xdr->codeUint32(&nchars))
+        return false;
+
+    JSContext *cx = xdr->cx();
+    JSAtom *atom;
+#if IS_LITTLE_ENDIAN
+    /* Directly access the little endian chars in the XDR buffer. */
+    const jschar *chars = reinterpret_cast<const jschar *>(xdr->buf.read(nchars * sizeof(jschar)));
+    atom = AtomizeChars(cx, chars, nchars);
+#else
+    /*
+     * We must copy chars to a temporary buffer to convert between little and
+     * big endian data.
+     */
+    jschar *chars;
+    jschar stackChars[256];
+    if (nchars <= ArrayLength(stackChars)) {
+        chars = stackChars;
+    } else {
+        /*
+         * This is very uncommon. Don't use the tempLifoAlloc arena for this as
+         * most allocations here will be bigger than tempLifoAlloc's default
+         * chunk size.
+         */
+        chars = cx->runtime()->pod_malloc<jschar>(nchars);
+        if (!chars)
+            return false;
+    }
+
+    JS_ALWAYS_TRUE(xdr->codeChars(chars, nchars));
+    atom = AtomizeChars(cx, chars, nchars);
+    if (chars != stackChars)
+        js_free(chars);
+#endif /* !IS_LITTLE_ENDIAN */
+
+    if (!atom)
+        return false;
+    atomp.set(atom);
+    return true;
+}
+
+template bool
+js::XDRAtom(XDRState<XDR_ENCODE> *xdr, MutableHandleAtom atomp);
+
+template bool
+js::XDRAtom(XDRState<XDR_DECODE> *xdr, MutableHandleAtom atomp);
+