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cobalt / cobalt / 4fe09471d0134f1d49ad5034a1c8867d6f9f4551 / . / src / third_party / mozjs / js / src / jsscript.cpp
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/* -*- 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 script operations.
*/
#include "jsscript.h"
#include <string.h>
#include "mozilla/PodOperations.h"
#include "jstypes.h"
#include "jsutil.h"
#include "jsapi.h"
#include "jsatom.h"
#include "jscntxt.h"
#include "jsdbgapi.h"
#include "jsfun.h"
#include "jsgc.h"
#include "jsopcode.h"
#include "gc/Marking.h"
#include "frontend/BytecodeEmitter.h"
#include "jit/IonCode.h"
#include "jit/BaselineJIT.h"
#include "vm/Debugger.h"
#include "vm/Interpreter.h"
#include "vm/Shape.h"
#include "vm/Xdr.h"
#include "jsinferinlines.h"
#include "jsscriptinlines.h"
#include "vm/Interpreter-inl.h"
#include "vm/RegExpObject-inl.h"
#include "vm/ScopeObject-inl.h"
#include "nb/memory_scope.h"
#ifdef USE_ZLIB
#include "zlib.h"
#endif
using namespace js;
using namespace js::gc;
using namespace js::frontend;
using mozilla::PodCopy;
using mozilla::PodZero;
typedef Rooted<GlobalObject *> RootedGlobalObject;
/* static */ unsigned
Bindings::argumentsVarIndex(JSContext *cx, InternalBindingsHandle bindings)
{
HandlePropertyName arguments = cx->names().arguments;
BindingIter bi(bindings);
while (bi->name() != arguments)
bi++;
return bi.frameIndex();
}
bool
Bindings::initWithTemporaryStorage(JSContext *cx, InternalBindingsHandle self,
unsigned numArgs, unsigned numVars,
Binding *bindingArray)
{
TRACK_MEMORY_SCOPE("Javascript");
JS_ASSERT(!self->callObjShape_);
JS_ASSERT(self->bindingArrayAndFlag_ == TEMPORARY_STORAGE_BIT);
if (numArgs > UINT16_MAX || numVars > UINT16_MAX) {
JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL,
self->numArgs_ > self->numVars_ ?
JSMSG_TOO_MANY_FUN_ARGS :
JSMSG_TOO_MANY_LOCALS);
return false;
}
JS_ASSERT(!(uintptr_t(bindingArray) & TEMPORARY_STORAGE_BIT));
self->bindingArrayAndFlag_ = uintptr_t(bindingArray) | TEMPORARY_STORAGE_BIT;
self->numArgs_ = numArgs;
self->numVars_ = numVars;
/*
* Get the initial shape to use when creating CallObjects for this script.
* Since unaliased variables are, by definition, only accessed by local
* operations and never through the scope chain, only give shapes to
* aliased variables. While the debugger may observe any scope object at
* any time, such accesses are mediated by DebugScopeProxy (see
* DebugScopeProxy::handleUnaliasedAccess).
*/
JS_STATIC_ASSERT(CallObject::RESERVED_SLOTS == 2);
gc::AllocKind allocKind = gc::FINALIZE_OBJECT2_BACKGROUND;
JS_ASSERT(gc::GetGCKindSlots(allocKind) == CallObject::RESERVED_SLOTS);
RootedShape initial(cx,
EmptyShape::getInitialShape(cx, &CallObject::class_, NULL, cx->global(), NULL,
allocKind, BaseShape::VAROBJ | BaseShape::DELEGATE));
if (!initial)
return false;
self->callObjShape_.init(initial);
#ifdef DEBUG
HashSet<PropertyName *> added(cx);
if (!added.init())
return false;
#endif
BindingIter bi(self);
unsigned slot = CallObject::RESERVED_SLOTS;
for (unsigned i = 0, n = self->count(); i < n; i++, bi++) {
if (!bi->aliased())
continue;
#ifdef DEBUG
/* The caller ensures no duplicate aliased names. */
JS_ASSERT(!added.has(bi->name()));
if (!added.put(bi->name()))
return false;
#endif
StackBaseShape base(cx->compartment(), &CallObject::class_, cx->global(), NULL,
BaseShape::VAROBJ | BaseShape::DELEGATE);
UnownedBaseShape *nbase = BaseShape::getUnowned(cx, base);
if (!nbase)
return false;
RootedId id(cx, NameToId(bi->name()));
unsigned attrs = JSPROP_PERMANENT | JSPROP_ENUMERATE |
(bi->kind() == CONSTANT ? JSPROP_READONLY : 0);
unsigned frameIndex = bi.frameIndex();
StackShape child(nbase, id, slot++, 0, attrs, Shape::HAS_SHORTID, frameIndex);
Shape *shape = self->callObjShape_->getChildBinding(cx, child);
if (!shape)
return false;
self->callObjShape_ = shape;
}
JS_ASSERT(!bi);
return true;
}
uint8_t *
Bindings::switchToScriptStorage(Binding *newBindingArray)
{
TRACK_MEMORY_SCOPE("Javascript");
JS_ASSERT(bindingArrayUsingTemporaryStorage());
JS_ASSERT(!(uintptr_t(newBindingArray) & TEMPORARY_STORAGE_BIT));
PodCopy(newBindingArray, bindingArray(), count());
bindingArrayAndFlag_ = uintptr_t(newBindingArray);
return reinterpret_cast<uint8_t *>(newBindingArray + count());
}
bool
Bindings::clone(JSContext *cx, InternalBindingsHandle self,
uint8_t *dstScriptData, HandleScript srcScript)
{
TRACK_MEMORY_SCOPE("Javascript");
/* The clone has the same bindingArray_ offset as 'src'. */
Bindings &src = srcScript->bindings;
ptrdiff_t off = (uint8_t *)src.bindingArray() - srcScript->data;
JS_ASSERT(off >= 0);
JS_ASSERT(off <= srcScript->dataSize);
Binding *dstPackedBindings = (Binding *)(dstScriptData + off);
/*
* Since atoms are shareable throughout the runtime, we can simply copy
* the source's bindingArray directly.
*/
if (!initWithTemporaryStorage(cx, self, src.numArgs(), src.numVars(), src.bindingArray()))
return false;
self->switchToScriptStorage(dstPackedBindings);
return true;
}
/* static */ Bindings
GCMethods<Bindings>::initial()
{
return Bindings();
}
template<XDRMode mode>
static bool
XDRScriptBindings(XDRState<mode> *xdr, LifoAllocScope &las, unsigned numArgs, unsigned numVars,
HandleScript script)
{
TRACK_MEMORY_SCOPE("Javascript");
JSContext *cx = xdr->cx();
if (mode == XDR_ENCODE) {
for (BindingIter bi(script); bi; bi++) {
RootedAtom atom(cx, bi->name());
if (!XDRAtom(xdr, &atom))
return false;
}
for (BindingIter bi(script); bi; bi++) {
uint8_t u8 = (uint8_t(bi->kind()) << 1) | uint8_t(bi->aliased());
if (!xdr->codeUint8(&u8))
return false;
}
} else {
unsigned nameCount = numArgs + numVars;
AutoValueVector atoms(cx);
if (!atoms.resize(nameCount))
return false;
for (unsigned i = 0; i < nameCount; i++) {
RootedAtom atom(cx);
if (!XDRAtom(xdr, &atom))
return false;
atoms[i] = StringValue(atom);
}
Binding *bindingArray = las.alloc().newArrayUninitialized<Binding>(nameCount);
if (!bindingArray)
return false;
for (unsigned i = 0; i < nameCount; i++) {
uint8_t u8;
if (!xdr->codeUint8(&u8))
return false;
PropertyName *name = atoms[i].toString()->asAtom().asPropertyName();
BindingKind kind = BindingKind(u8 >> 1);
bool aliased = bool(u8 & 1);
bindingArray[i] = Binding(name, kind, aliased);
}
InternalBindingsHandle bindings(script, &script->bindings);
if (!Bindings::initWithTemporaryStorage(cx, bindings, numArgs, numVars, bindingArray))
return false;
}
return true;
}
bool
Bindings::bindingIsAliased(unsigned bindingIndex)
{
JS_ASSERT(bindingIndex < count());
return bindingArray()[bindingIndex].aliased();
}
void
Bindings::trace(JSTracer *trc)
{
TRACK_MEMORY_SCOPE("Javascript");
if (callObjShape_)
MarkShape(trc, &callObjShape_, "callObjShape");
/*
* As the comment in Bindings explains, bindingsArray may point into freed
* storage when bindingArrayUsingTemporaryStorage so we don't mark it.
* Note: during compilation, atoms are already kept alive by gcKeepAtoms.
*/
if (bindingArrayUsingTemporaryStorage())
return;
for (Binding *b = bindingArray(), *end = b + count(); b != end; b++) {
PropertyName *name = b->name();
MarkStringUnbarriered(trc, &name, "bindingArray");
}
}
bool
js::FillBindingVector(HandleScript fromScript, BindingVector *vec)
{
TRACK_MEMORY_SCOPE("Javascript");
for (BindingIter bi(fromScript); bi; bi++) {
if (!vec->append(*bi))
return false;
}
return true;
}
template<XDRMode mode>
static bool
XDRScriptConst(XDRState<mode> *xdr, HeapValue *vp)
{
TRACK_MEMORY_SCOPE("Javascript");
JSContext *cx = xdr->cx();
/*
* A script constant can be an arbitrary primitive value as they are used
* to implement JSOP_LOOKUPSWITCH. But they cannot be objects, see
* bug 407186.
*/
enum ConstTag {
SCRIPT_INT = 0,
SCRIPT_DOUBLE = 1,
SCRIPT_ATOM = 2,
SCRIPT_TRUE = 3,
SCRIPT_FALSE = 4,
SCRIPT_NULL = 5,
SCRIPT_VOID = 6
};
uint32_t tag;
if (mode == XDR_ENCODE) {
if (vp->isInt32()) {
tag = SCRIPT_INT;
} else if (vp->isDouble()) {
tag = SCRIPT_DOUBLE;
} else if (vp->isString()) {
tag = SCRIPT_ATOM;
} else if (vp->isTrue()) {
tag = SCRIPT_TRUE;
} else if (vp->isFalse()) {
tag = SCRIPT_FALSE;
} else if (vp->isNull()) {
tag = SCRIPT_NULL;
} else {
JS_ASSERT(vp->isUndefined());
tag = SCRIPT_VOID;
}
}
if (!xdr->codeUint32(&tag))
return false;
switch (tag) {
case SCRIPT_INT: {
uint32_t i;
if (mode == XDR_ENCODE)
i = uint32_t(vp->toInt32());
if (!xdr->codeUint32(&i))
return JS_FALSE;
if (mode == XDR_DECODE)
vp->init(Int32Value(int32_t(i)));
break;
}
case SCRIPT_DOUBLE: {
double d;
if (mode == XDR_ENCODE)
d = vp->toDouble();
if (!xdr->codeDouble(&d))
return false;
if (mode == XDR_DECODE)
vp->init(DoubleValue(d));
break;
}
case SCRIPT_ATOM: {
RootedAtom atom(cx);
if (mode == XDR_ENCODE)
atom = &vp->toString()->asAtom();
if (!XDRAtom(xdr, &atom))
return false;
if (mode == XDR_DECODE)
vp->init(StringValue(atom));
break;
}
case SCRIPT_TRUE:
if (mode == XDR_DECODE)
vp->init(BooleanValue(true));
break;
case SCRIPT_FALSE:
if (mode == XDR_DECODE)
vp->init(BooleanValue(false));
break;
case SCRIPT_NULL:
if (mode == XDR_DECODE)
vp->init(NullValue());
break;
case SCRIPT_VOID:
if (mode == XDR_DECODE)
vp->init(UndefinedValue());
break;
}
return true;
}
static inline uint32_t
FindBlockIndex(JSScript *script, StaticBlockObject &block)
{
ObjectArray *objects = script->objects();
HeapPtrObject *vector = objects->vector;
unsigned length = objects->length;
for (unsigned i = 0; i < length; ++i) {
if (vector[i] == &block)
return i;
}
JS_NOT_REACHED("Block not found");
return UINT32_MAX;
}
template<XDRMode mode>
bool
js::XDRScript(XDRState<mode> *xdr, HandleObject enclosingScope, HandleScript enclosingScript,
HandleFunction fun, MutableHandleScript scriptp)
{
TRACK_MEMORY_SCOPE("Javascript");
/* NB: Keep this in sync with CloneScript. */
enum ScriptBits {
NoScriptRval,
SavedCallerFun,
Strict,
ContainsDynamicNameAccess,
FunHasExtensibleScope,
FunNeedsDeclEnvObject,
FunHasAnyAliasedFormal,
ArgumentsHasVarBinding,
NeedsArgsObj,
IsGenerator,
IsGeneratorExp,
OwnSource,
ExplicitUseStrict,
SelfHosted
};
uint32_t length, lineno, nslots;
uint32_t natoms, nsrcnotes, ntrynotes, nobjects, nregexps, nconsts, i;
uint32_t prologLength, version;
uint32_t ndefaults = 0;
uint32_t nTypeSets = 0;
uint32_t scriptBits = 0;
JSContext *cx = xdr->cx();
RootedScript script(cx);
nsrcnotes = ntrynotes = natoms = nobjects = nregexps = nconsts = 0;
/* XDR arguments and vars. */
uint16_t nargs = 0, nvars = 0;
uint32_t argsVars = 0;
if (mode == XDR_ENCODE) {
script = scriptp.get();
JS_ASSERT_IF(enclosingScript, enclosingScript->compartment() == script->compartment());
nargs = script->bindings.numArgs();
nvars = script->bindings.numVars();
argsVars = (nargs << 16) | nvars;
}
if (!xdr->codeUint32(&argsVars))
return false;
if (mode == XDR_DECODE) {
nargs = argsVars >> 16;
nvars = argsVars & 0xFFFF;
}
if (mode == XDR_ENCODE)
length = script->length;
if (!xdr->codeUint32(&length))
return JS_FALSE;
if (mode == XDR_ENCODE) {
prologLength = script->mainOffset;
JS_ASSERT(script->getVersion() != JSVERSION_UNKNOWN);
version = (uint32_t)script->getVersion() | (script->nfixed << 16);
lineno = script->lineno;
nslots = (uint32_t)script->nslots;
nslots = (uint32_t)((script->staticLevel << 16) | script->nslots);
natoms = script->natoms;
nsrcnotes = script->numNotes();
if (script->hasConsts())
nconsts = script->consts()->length;
if (script->hasObjects())
nobjects = script->objects()->length;
if (script->hasRegexps())
nregexps = script->regexps()->length;
if (script->hasTrynotes())
ntrynotes = script->trynotes()->length;
nTypeSets = script->nTypeSets;
ndefaults = script->ndefaults;
if (script->noScriptRval)
scriptBits |= (1 << NoScriptRval);
if (script->savedCallerFun)
scriptBits |= (1 << SavedCallerFun);
if (script->strict)
scriptBits |= (1 << Strict);
if (script->explicitUseStrict)
scriptBits |= (1 << ExplicitUseStrict);
if (script->selfHosted)
scriptBits |= (1 << SelfHosted);
if (script->bindingsAccessedDynamically)
scriptBits |= (1 << ContainsDynamicNameAccess);
if (script->funHasExtensibleScope)
scriptBits |= (1 << FunHasExtensibleScope);
if (script->funNeedsDeclEnvObject)
scriptBits |= (1 << FunNeedsDeclEnvObject);
if (script->funHasAnyAliasedFormal)
scriptBits |= (1 << FunHasAnyAliasedFormal);
if (script->argumentsHasVarBinding())
scriptBits |= (1 << ArgumentsHasVarBinding);
if (script->analyzedArgsUsage() && script->needsArgsObj())
scriptBits |= (1 << NeedsArgsObj);
if (!enclosingScript || enclosingScript->scriptSource() != script->scriptSource())
scriptBits |= (1 << OwnSource);
if (script->isGenerator)
scriptBits |= (1 << IsGenerator);
if (script->isGeneratorExp)
scriptBits |= (1 << IsGeneratorExp);
JS_ASSERT(!script->compileAndGo);
JS_ASSERT(!script->hasSingletons);
}
if (!xdr->codeUint32(&prologLength))
return JS_FALSE;
if (!xdr->codeUint32(&version))
return JS_FALSE;
/*
* To fuse allocations, we need srcnote, atom, objects, regexp, and trynote
* counts early.
*/
if (!xdr->codeUint32(&natoms))
return JS_FALSE;
if (!xdr->codeUint32(&nsrcnotes))
return JS_FALSE;
if (!xdr->codeUint32(&ntrynotes))
return JS_FALSE;
if (!xdr->codeUint32(&nobjects))
return JS_FALSE;
if (!xdr->codeUint32(&nregexps))
return JS_FALSE;
if (!xdr->codeUint32(&nconsts))
return JS_FALSE;
if (!xdr->codeUint32(&nTypeSets))
return JS_FALSE;
if (!xdr->codeUint32(&ndefaults))
return JS_FALSE;
if (!xdr->codeUint32(&scriptBits))
return JS_FALSE;
if (mode == XDR_DECODE) {
/* Note: version is packed into the 32b space with another 16b value. */
JSVersion version_ = JSVersion(version & JS_BITMASK(16));
JS_ASSERT((version_ & VersionFlags::MASK) == unsigned(version_));
// principals and originPrincipals are set with xdr->initScriptPrincipals(script) below.
// staticLevel is set below.
CompileOptions options(cx);
options.setVersion(version_)
.setNoScriptRval(!!(scriptBits & (1 << NoScriptRval)))
.setSelfHostingMode(!!(scriptBits & (1 << SelfHosted)));
JS::RootedScriptSource sourceObject(cx);
if (scriptBits & (1 << OwnSource)) {
ScriptSource *ss = cx->new_<ScriptSource>();
if (!ss)
return false;
sourceObject = ScriptSourceObject::create(cx, ss);
if (!sourceObject)
return false;
} else {
JS_ASSERT(enclosingScript);
sourceObject = enclosingScript->sourceObject();
}
script = JSScript::Create(cx, enclosingScope, !!(scriptBits & (1 << SavedCallerFun)),
options, /* staticLevel = */ 0, sourceObject, 0, 0);
if (!script)
return false;
}
/* JSScript::partiallyInit assumes script->bindings is fully initialized. */
LifoAllocScope las(&cx->tempLifoAlloc());
if (!XDRScriptBindings(xdr, las, nargs, nvars, script))
return false;
if (mode == XDR_DECODE) {
if (!JSScript::partiallyInit(cx, script, nobjects, nregexps, ntrynotes, nconsts, nTypeSets))
return false;
JS_ASSERT(!script->mainOffset);
script->mainOffset = prologLength;
script->length = length;
script->nfixed = uint16_t(version >> 16);
script->ndefaults = ndefaults;
scriptp.set(script);
if (scriptBits & (1 << Strict))
script->strict = true;
if (scriptBits & (1 << ExplicitUseStrict))
script->explicitUseStrict = true;
if (scriptBits & (1 << ContainsDynamicNameAccess))
script->bindingsAccessedDynamically = true;
if (scriptBits & (1 << FunHasExtensibleScope))
script->funHasExtensibleScope = true;
if (scriptBits & (1 << FunNeedsDeclEnvObject))
script->funNeedsDeclEnvObject = true;
if (scriptBits & (1 << FunHasAnyAliasedFormal))
script->funHasAnyAliasedFormal = true;
if (scriptBits & (1 << ArgumentsHasVarBinding))
script->setArgumentsHasVarBinding();
if (scriptBits & (1 << NeedsArgsObj))
script->setNeedsArgsObj(true);
if (scriptBits & (1 << IsGenerator))
script->isGenerator = true;
if (scriptBits & (1 << IsGeneratorExp))
script->isGeneratorExp = true;
}
JS_STATIC_ASSERT(sizeof(jsbytecode) == 1);
JS_STATIC_ASSERT(sizeof(jssrcnote) == 1);
if (scriptBits & (1 << OwnSource)) {
if (!script->scriptSource()->performXDR<mode>(xdr))
return false;
}
if (!xdr->codeUint32(&script->sourceStart))
return false;
if (!xdr->codeUint32(&script->sourceEnd))
return false;
if (!xdr->codeUint32(&lineno) || !xdr->codeUint32(&nslots))
return false;
if (mode == XDR_DECODE) {
script->lineno = lineno;
script->nslots = uint16_t(nslots);
script->staticLevel = uint16_t(nslots >> 16);
xdr->initScriptPrincipals(script);
}
jsbytecode *code = script->code;
SharedScriptData *ssd;
if (mode == XDR_DECODE) {
ssd = SharedScriptData::new_(cx, length, nsrcnotes, natoms);
if (!ssd)
return false;
code = ssd->data;
if (natoms != 0) {
script->natoms = natoms;
script->atoms = ssd->atoms(length, nsrcnotes);
}
}
if (!xdr->codeBytes(code, length) || !xdr->codeBytes(code + length, nsrcnotes)) {
if (mode == XDR_DECODE)
js_free(ssd);
return false;
}
for (i = 0; i != natoms; ++i) {
if (mode == XDR_DECODE) {
RootedAtom tmp(cx);
if (!XDRAtom(xdr, &tmp))
return false;
script->atoms[i].init(tmp);
} else {
RootedAtom tmp(cx, script->atoms[i]);
if (!XDRAtom(xdr, &tmp))
return false;
}
}
if (mode == XDR_DECODE) {
if (!SaveSharedScriptData(cx, script, ssd))
return false;
}
/*
* Here looping from 0-to-length to xdr objects is essential to ensure that
* all references to enclosing blocks (via FindBlockIndex below) happen
* after the enclosing block has been XDR'd.
*/
for (i = 0; i != nobjects; ++i) {
HeapPtr<JSObject> *objp = &script->objects()->vector[i];
uint32_t isBlock;
if (mode == XDR_ENCODE) {
JSObject *obj = *objp;
JS_ASSERT(obj->is<JSFunction>() || obj->is<StaticBlockObject>());
isBlock = obj->is<BlockObject>() ? 1 : 0;
}
if (!xdr->codeUint32(&isBlock))
return false;
if (isBlock == 0) {
/* Code the nested function's enclosing scope. */
uint32_t funEnclosingScopeIndex = 0;
if (mode == XDR_ENCODE) {
JSScript *innerScript = (*objp)->as<JSFunction>().getOrCreateScript(cx);
if (!innerScript)
return false;
RootedObject staticScope(cx, innerScript->enclosingStaticScope());
StaticScopeIter ssi(cx, staticScope);
if (ssi.done() || ssi.type() == StaticScopeIter::FUNCTION) {
JS_ASSERT(ssi.done() == !fun);
funEnclosingScopeIndex = UINT32_MAX;
} else {
funEnclosingScopeIndex = FindBlockIndex(script, ssi.block());
JS_ASSERT(funEnclosingScopeIndex < i);
}
}
if (!xdr->codeUint32(&funEnclosingScopeIndex))
return false;
Rooted<JSObject*> funEnclosingScope(cx);
if (mode == XDR_DECODE) {
if (funEnclosingScopeIndex == UINT32_MAX) {
funEnclosingScope = fun;
} else {
JS_ASSERT(funEnclosingScopeIndex < i);
funEnclosingScope = script->objects()->vector[funEnclosingScopeIndex];
}
}
RootedObject tmp(cx, *objp);
if (!XDRInterpretedFunction(xdr, funEnclosingScope, script, &tmp))
return false;
*objp = tmp;
} else {
/* Code the nested block's enclosing scope. */
JS_ASSERT(isBlock == 1);
uint32_t blockEnclosingScopeIndex = 0;
if (mode == XDR_ENCODE) {
if (StaticBlockObject *block = (*objp)->as<StaticBlockObject>().enclosingBlock())
blockEnclosingScopeIndex = FindBlockIndex(script, *block);
else
blockEnclosingScopeIndex = UINT32_MAX;
}
if (!xdr->codeUint32(&blockEnclosingScopeIndex))
return false;
Rooted<JSObject*> blockEnclosingScope(cx);
if (mode == XDR_DECODE) {
if (blockEnclosingScopeIndex != UINT32_MAX) {
JS_ASSERT(blockEnclosingScopeIndex < i);
blockEnclosingScope = script->objects()->vector[blockEnclosingScopeIndex];
} else {
blockEnclosingScope = fun;
}
}
Rooted<StaticBlockObject*> tmp(cx, static_cast<StaticBlockObject *>(objp->get()));
if (!XDRStaticBlockObject(xdr, blockEnclosingScope, script, tmp.address()))
return false;
*objp = tmp;
}
}
for (i = 0; i != nregexps; ++i) {
if (!XDRScriptRegExpObject(xdr, &script->regexps()->vector[i]))
return false;
}
if (ntrynotes != 0) {
/*
* We combine tn->kind and tn->stackDepth when serializing as XDR is not
* efficient when serializing small integer types.
*/
JSTryNote *tn, *tnfirst;
uint32_t kindAndDepth;
JS_STATIC_ASSERT(sizeof(tn->kind) == sizeof(uint8_t));
JS_STATIC_ASSERT(sizeof(tn->stackDepth) == sizeof(uint16_t));
tnfirst = script->trynotes()->vector;
JS_ASSERT(script->trynotes()->length == ntrynotes);
tn = tnfirst + ntrynotes;
do {
--tn;
if (mode == XDR_ENCODE) {
kindAndDepth = (uint32_t(tn->kind) << 16)
| uint32_t(tn->stackDepth);
}
if (!xdr->codeUint32(&kindAndDepth) ||
!xdr->codeUint32(&tn->start) ||
!xdr->codeUint32(&tn->length)) {
return false;
}
if (mode == XDR_DECODE) {
tn->kind = uint8_t(kindAndDepth >> 16);
tn->stackDepth = uint16_t(kindAndDepth);
}
} while (tn != tnfirst);
}
if (nconsts) {
HeapValue *vector = script->consts()->vector;
for (i = 0; i != nconsts; ++i) {
if (!XDRScriptConst(xdr, &vector[i]))
return false;
}
}
if (mode == XDR_DECODE) {
if (cx->hasOption(JSOPTION_PCCOUNT))
(void) script->initScriptCounts(cx);
scriptp.set(script);
}
return true;
}
template bool
js::XDRScript(XDRState<XDR_ENCODE> *, HandleObject, HandleScript, HandleFunction,
MutableHandleScript);
template bool
js::XDRScript(XDRState<XDR_DECODE> *, HandleObject, HandleScript, HandleFunction,
MutableHandleScript);
void
JSScript::setSourceObject(js::ScriptSourceObject *object)
{
sourceObject_ = object;
}
js::ScriptSourceObject *
JSScript::sourceObject() const
{
return &sourceObject_->as<ScriptSourceObject>();
}
bool
JSScript::initScriptCounts(JSContext *cx)
{
TRACK_MEMORY_SCOPE("Javascript");
JS_ASSERT(!hasScriptCounts);
size_t n = 0;
jsbytecode *pc, *next;
for (pc = code; pc < code + length; pc = next) {
n += PCCounts::numCounts(JSOp(*pc));
next = pc + GetBytecodeLength(pc);
}
size_t bytes = (length * sizeof(PCCounts)) + (n * sizeof(double));
char *base = (char *) cx->calloc_(bytes);
if (!base)
return false;
/* Create compartment's scriptCountsMap if necessary. */
ScriptCountsMap *map = compartment()->scriptCountsMap;
if (!map) {
map = cx->new_<ScriptCountsMap>();
if (!map || !map->init()) {
js_free(base);
js_delete(map);
return false;
}
compartment()->scriptCountsMap = map;
}
char *cursor = base;
ScriptCounts scriptCounts;
scriptCounts.pcCountsVector = (PCCounts *) cursor;
cursor += length * sizeof(PCCounts);
for (pc = code; pc < code + length; pc = next) {
JS_ASSERT(uintptr_t(cursor) % sizeof(double) == 0);
scriptCounts.pcCountsVector[pc - code].counts = (double *) cursor;
size_t capacity = PCCounts::numCounts(JSOp(*pc));
#ifdef DEBUG
scriptCounts.pcCountsVector[pc - code].capacity = capacity;
#endif
cursor += capacity * sizeof(double);
next = pc + GetBytecodeLength(pc);
}
if (!map->putNew(this, scriptCounts)) {
js_free(base);
return false;
}
hasScriptCounts = true; // safe to set this; we can't fail after this point
JS_ASSERT(size_t(cursor - base) == bytes);
/* Enable interrupts in any interpreter frames running on this script. */
InterpreterFrames *frames;
for (frames = cx->runtime()->interpreterFrames; frames; frames = frames->older)
frames->enableInterruptsIfRunning(this);
return true;
}
static inline ScriptCountsMap::Ptr GetScriptCountsMapEntry(JSScript *script)
{
JS_ASSERT(script->hasScriptCounts);
ScriptCountsMap *map = script->compartment()->scriptCountsMap;
ScriptCountsMap::Ptr p = map->lookup(script);
JS_ASSERT(p);
return p;
}
js::PCCounts
JSScript::getPCCounts(jsbytecode *pc) {
JS_ASSERT(size_t(pc - code) < length);
ScriptCountsMap::Ptr p = GetScriptCountsMapEntry(this);
return p->value.pcCountsVector[pc - code];
}
void
JSScript::addIonCounts(jit::IonScriptCounts *ionCounts)
{
TRACK_MEMORY_SCOPE("Javascript");
ScriptCountsMap::Ptr p = GetScriptCountsMapEntry(this);
if (p->value.ionCounts)
ionCounts->setPrevious(p->value.ionCounts);
p->value.ionCounts = ionCounts;
}
jit::IonScriptCounts *
JSScript::getIonCounts()
{
ScriptCountsMap::Ptr p = GetScriptCountsMapEntry(this);
return p->value.ionCounts;
}
ScriptCounts
JSScript::releaseScriptCounts()
{
ScriptCountsMap::Ptr p = GetScriptCountsMapEntry(this);
ScriptCounts counts = p->value;
compartment()->scriptCountsMap->remove(p);
hasScriptCounts = false;
return counts;
}
void
JSScript::destroyScriptCounts(FreeOp *fop)
{
if (hasScriptCounts) {
ScriptCounts scriptCounts = releaseScriptCounts();
scriptCounts.destroy(fop);
}
}
void
ScriptSourceObject::setSource(ScriptSource *source)
{
TRACK_MEMORY_SCOPE("Javascript");
if (source)
source->incref();
if (this->source())
this->source()->decref();
setReservedSlot(SOURCE_SLOT, PrivateValue(source));
}
void
ScriptSourceObject::finalize(FreeOp *fop, JSObject *obj)
{
// ScriptSource::setSource automatically takes care of the refcount
obj->as<ScriptSourceObject>().setSource(NULL);
}
Class ScriptSourceObject::class_ = {
"ScriptSource",
JSCLASS_HAS_RESERVED_SLOTS(1) | JSCLASS_IS_ANONYMOUS,
JS_PropertyStub, /* addProperty */
JS_DeletePropertyStub, /* delProperty */
JS_PropertyStub, /* getProperty */
JS_StrictPropertyStub, /* setProperty */
JS_EnumerateStub,
JS_ResolveStub,
JS_ConvertStub,
ScriptSourceObject::finalize
};
ScriptSourceObject *
ScriptSourceObject::create(JSContext *cx, ScriptSource *source)
{
TRACK_MEMORY_SCOPE("Javascript");
RootedObject object(cx, NewObjectWithGivenProto(cx, &class_, NULL, cx->global()));
if (!object)
return NULL;
JS::RootedScriptSource sourceObject(cx, &object->as<ScriptSourceObject>());
sourceObject->setSlot(SOURCE_SLOT, PrivateValue(source));
source->incref();
return sourceObject;
}
#ifdef JS_THREADSAFE
void
SourceCompressorThread::compressorThread(void *arg)
{
PR_SetCurrentThreadName("JS Source Compressing Thread");
static_cast<SourceCompressorThread *>(arg)->threadLoop();
}
bool
SourceCompressorThread::init()
{
JS_ASSERT(!thread);
lock = PR_NewLock();
if (!lock)
return false;
wakeup = PR_NewCondVar(lock);
if (!wakeup)
return false;
done = PR_NewCondVar(lock);
if (!done)
return false;
thread = PR_CreateThread(PR_USER_THREAD, compressorThread, this, PR_PRIORITY_NORMAL,
PR_GLOBAL_THREAD, PR_JOINABLE_THREAD, 0);
if (!thread)
return false;
return true;
}
void
SourceCompressorThread::finish()
{
if (thread) {
PR_Lock(lock);
// We should only be compressing things when in the compiler.
JS_ASSERT(state == IDLE);
PR_NotifyCondVar(wakeup);
state = SHUTDOWN;
PR_Unlock(lock);
PR_JoinThread(thread);
}
if (wakeup)
PR_DestroyCondVar(wakeup);
if (done)
PR_DestroyCondVar(done);
if (lock)
PR_DestroyLock(lock);
}
const jschar *
SourceCompressorThread::currentChars() const
{
JS_ASSERT(tok);
return tok->chars;
}
bool
SourceCompressorThread::internalCompress()
{
JS_ASSERT(state == COMPRESSING);
JS_ASSERT(tok);
ScriptSource *ss = tok->ss;
JS_ASSERT(!ss->ready());
size_t compressedLength = 0;
size_t nbytes = sizeof(jschar) * ss->length_;
// Memory allocation functions on JSRuntime and JSContext are not
// threadsafe. We have to use the js_* variants.
#ifdef USE_ZLIB
const size_t COMPRESS_THRESHOLD = 512;
if (nbytes >= COMPRESS_THRESHOLD) {
// Try to keep the maximum memory usage down by only allocating half the
// size of the string, first.
size_t firstSize = nbytes / 2;
if (!ss->adjustDataSize(firstSize))
return false;
Compressor comp(reinterpret_cast<const unsigned char *>(tok->chars), nbytes);
if (!comp.init())
return false;
comp.setOutput(ss->data.compressed, firstSize);
bool cont = !stop;
while (cont) {
switch (comp.compressMore()) {
case Compressor::CONTINUE:
break;
case Compressor::MOREOUTPUT: {
if (comp.outWritten() == nbytes) {
cont = false;
break;
}
// The compressed output is greater than half the size of the
// original string. Reallocate to the full size.
if (!ss->adjustDataSize(nbytes))
return false;
comp.setOutput(ss->data.compressed, nbytes);
break;
}
case Compressor::DONE:
cont = false;
break;
case Compressor::OOM:
return false;
}
cont = cont && !stop;
}
compressedLength = comp.outWritten();
if (stop || compressedLength == nbytes)
compressedLength = 0;
}
#endif
if (compressedLength == 0) {
if (!ss->adjustDataSize(nbytes))
return false;
PodCopy(ss->data.source, tok->chars, ss->length());
} else {
// Shrink the buffer to the size of the compressed data. Shouldn't fail.
JS_ALWAYS_TRUE(ss->adjustDataSize(compressedLength));
}
ss->compressedLength_ = compressedLength;
return true;
}
void
SourceCompressorThread::threadLoop()
{
PR_Lock(lock);
while (true) {
switch (state) {
case SHUTDOWN:
PR_Unlock(lock);
return;
case IDLE:
PR_WaitCondVar(wakeup, PR_INTERVAL_NO_TIMEOUT);
break;
case COMPRESSING:
if (!internalCompress())
tok->oom = true;
// We hold the lock, so no one should have changed this.
JS_ASSERT(state == COMPRESSING);
state = IDLE;
PR_NotifyCondVar(done);
break;
}
}
}
void
SourceCompressorThread::compress(SourceCompressionToken *sct)
{
if (tok)
// We have reentered the compiler. Complete the current compression
// before starting the next one.
waitOnCompression(tok);
JS_ASSERT(state == IDLE);
JS_ASSERT(!tok);
stop = false;
PR_Lock(lock);
sct->ss->ready_ = false;
tok = sct;
state = COMPRESSING;
PR_NotifyCondVar(wakeup);
PR_Unlock(lock);
}
void
SourceCompressorThread::waitOnCompression(SourceCompressionToken *userTok)
{
JS_ASSERT(userTok == tok);
PR_Lock(lock);
while (state == COMPRESSING)
PR_WaitCondVar(done, PR_INTERVAL_NO_TIMEOUT);
JS_ASSERT(state == IDLE);
SourceCompressionToken *saveTok = tok;
tok = NULL;
PR_Unlock(lock);
JS_ASSERT(!saveTok->ss->ready());
saveTok->ss->ready_ = true;
// Update memory accounting.
if (!saveTok->oom)
saveTok->cx->runtime()->updateMallocCounter(NULL, saveTok->ss->computedSizeOfData());
saveTok->ss = NULL;
saveTok->chars = NULL;
}
void
SourceCompressorThread::abort(SourceCompressionToken *userTok)
{
JS_ASSERT(userTok == tok);
stop = true;
}
#endif /* JS_THREADSAFE */
static const unsigned char emptySource[] = "";
/* Adjust the amount of memory this script source uses for source data,
reallocating if needed. */
bool
ScriptSource::adjustDataSize(size_t nbytes)
{
TRACK_MEMORY_SCOPE("Javascript");
// Allocating 0 bytes has undefined behavior, so special-case it.
if (nbytes == 0) {
if (data.compressed != emptySource)
js_free(data.compressed);
data.compressed = const_cast<unsigned char *>(emptySource);
return true;
}
// |data.compressed| can be NULL.
void *buf = js_realloc(data.compressed, nbytes);
if (!buf && data.compressed != emptySource)
js_free(data.compressed);
data.compressed = static_cast<unsigned char *>(buf);
return !!data.compressed;
}
/* static */ bool
JSScript::loadSource(JSContext *cx, HandleScript script, bool *worked)
{
JS_ASSERT(!script->scriptSource()->hasSourceData());
*worked = false;
if (!cx->runtime()->sourceHook || !script->scriptSource()->sourceRetrievable())
return true;
jschar *src = NULL;
uint32_t length;
if (!cx->runtime()->sourceHook(cx, script, &src, &length))
return false;
if (!src)
return true;
ScriptSource *ss = script->scriptSource();
ss->setSource(src, length);
*worked = true;
return true;
}
JSFlatString *
JSScript::sourceData(JSContext *cx)
{
JS_ASSERT(scriptSource()->hasSourceData());
return scriptSource()->substring(cx, sourceStart, sourceEnd);
}
JSStableString *
SourceDataCache::lookup(ScriptSource *ss)
{
if (!map_)
return NULL;
if (Map::Ptr p = map_->lookup(ss))
return p->value;
return NULL;
}
void
SourceDataCache::put(ScriptSource *ss, JSStableString *str)
{
if (!map_) {
map_ = js_new<Map>();
if (!map_)
return;
if (!map_->init()) {
purge();
return;
}
}
(void) map_->put(ss, str);
}
void
SourceDataCache::purge()
{
js_delete(map_);
map_ = NULL;
}
const jschar *
ScriptSource::chars(JSContext *cx)
{
#ifdef JS_THREADSAFE
if (!ready())
return cx->runtime()->sourceCompressorThread.currentChars();
#endif
#ifdef USE_ZLIB
if (compressed()) {
JSStableString *cached = cx->runtime()->sourceDataCache.lookup(this);
if (!cached) {
const size_t nbytes = sizeof(jschar) * (length_ + 1);
jschar *decompressed = static_cast<jschar *>(cx->malloc_(nbytes));
if (!decompressed)
return NULL;
if (!DecompressString(data.compressed, compressedLength_,
reinterpret_cast<unsigned char *>(decompressed), nbytes)) {
JS_ReportOutOfMemory(cx);
js_free(decompressed);
return NULL;
}
decompressed[length_] = 0;
cached = js_NewString<CanGC>(cx, decompressed, length_);
if (!cached) {
js_free(decompressed);
return NULL;
}
cx->runtime()->sourceDataCache.put(this, cached);
}
return cached->chars().get();
}
#endif
return data.source;
}
JSStableString *
ScriptSource::substring(JSContext *cx, uint32_t start, uint32_t stop)
{
JS_ASSERT(start <= stop);
const jschar *chars = this->chars(cx);
if (!chars)
return NULL;
JSFlatString *flatStr = js_NewStringCopyN<CanGC>(cx, chars + start, stop - start);
if (!flatStr)
return NULL;
return flatStr->ensureStable(cx);
}
bool
ScriptSource::setSourceCopy(JSContext *cx, const jschar *src, uint32_t length,
bool argumentsNotIncluded, SourceCompressionToken *tok)
{
JS_ASSERT(!hasSourceData());
length_ = length;
argumentsNotIncluded_ = argumentsNotIncluded;
#ifdef JS_THREADSAFE
if (tok && cx->runtime()->useHelperThreads()) {
tok->ss = this;
tok->chars = src;
cx->runtime()->sourceCompressorThread.compress(tok);
} else
#endif
{
if (!adjustDataSize(sizeof(jschar) * length))
return false;
PodCopy(data.source, src, length_);
}
return true;
}
void
ScriptSource::setSource(const jschar *src, uint32_t length)
{
JS_ASSERT(!hasSourceData());
length_ = length;
JS_ASSERT(!argumentsNotIncluded_);
data.source = const_cast<jschar *>(src);
}
bool
SourceCompressionToken::complete()
{
JS_ASSERT_IF(!ss, !chars);
#ifdef JS_THREADSAFE
if (active()) {
cx->runtime()->sourceCompressorThread.waitOnCompression(this);
JS_ASSERT(!active());
}
if (oom) {
JS_ReportOutOfMemory(cx);
return false;
}
#endif
return true;
}
void
SourceCompressionToken::abort()
{
JS_ASSERT(active());
#ifdef JS_THREADSAFE
cx->runtime()->sourceCompressorThread.abort(this);
#endif
}
void
ScriptSource::destroy()
{
JS_ASSERT(ready());
adjustDataSize(0);
js_free(filename_);
js_free(sourceMap_);
ready_ = false;
js_free(this);
}
size_t
ScriptSource::sizeOfIncludingThis(JSMallocSizeOfFun mallocSizeOf)
{
// |data| is a union, but both members are pointers to allocated memory,
// |emptySource|, or NULL, so just using |data.compressed| will work.
size_t n = mallocSizeOf(this);
n += (ready() && data.compressed != emptySource)
? mallocSizeOf(data.compressed)
: 0;
n += mallocSizeOf(filename_);
return n;
}
template<XDRMode mode>
bool
ScriptSource::performXDR(XDRState<mode> *xdr)
{
uint8_t hasSource = hasSourceData();
if (!xdr->codeUint8(&hasSource))
return false;
uint8_t retrievable = sourceRetrievable_;
if (!xdr->codeUint8(&retrievable))
return false;
sourceRetrievable_ = retrievable;
if (hasSource && !sourceRetrievable_) {
// Only set members when we know decoding cannot fail. This prevents the
// script source from being partially initialized.
uint32_t length = length_;
if (!xdr->codeUint32(&length))
return false;
uint32_t compressedLength = compressedLength_;
if (!xdr->codeUint32(&compressedLength))
return false;
uint8_t argumentsNotIncluded = argumentsNotIncluded_;
if (!xdr->codeUint8(&argumentsNotIncluded))
return false;
size_t byteLen = compressedLength ? compressedLength : (length * sizeof(jschar));
if (mode == XDR_DECODE) {
if (!adjustDataSize(byteLen))
return false;
}
if (!xdr->codeBytes(data.compressed, byteLen)) {
if (mode == XDR_DECODE) {
js_free(data.compressed);
data.compressed = NULL;
}
return false;
}
length_ = length;
compressedLength_ = compressedLength;
argumentsNotIncluded_ = argumentsNotIncluded;
}
uint8_t haveSourceMap = hasSourceMap();
if (!xdr->codeUint8(&haveSourceMap))
return false;
if (haveSourceMap) {
uint32_t sourceMapLen = (mode == XDR_DECODE) ? 0 : js_strlen(sourceMap_);
if (!xdr->codeUint32(&sourceMapLen))
return false;
if (mode == XDR_DECODE) {
size_t byteLen = (sourceMapLen + 1) * sizeof(jschar);
sourceMap_ = static_cast<jschar *>(xdr->cx()->malloc_(byteLen));
if (!sourceMap_)
return false;
}
if (!xdr->codeChars(sourceMap_, sourceMapLen)) {
if (mode == XDR_DECODE) {
js_free(sourceMap_);
sourceMap_ = NULL;
}
return false;
}
sourceMap_[sourceMapLen] = '\0';
}
uint8_t haveFilename = !!filename_;
if (!xdr->codeUint8(&haveFilename))
return false;
if (haveFilename) {
const char *fn = filename();
if (!xdr->codeCString(&fn))
return false;
if (mode == XDR_DECODE && !setFilename(xdr->cx(), fn))
return false;
}
if (mode == XDR_DECODE)
ready_ = true;
return true;
}
bool
ScriptSource::setFilename(JSContext *cx, const char *filename)
{
JS_ASSERT(!filename_);
size_t len = strlen(filename) + 1;
if (len == 1)
return true;
filename_ = cx->pod_malloc<char>(len);
if (!filename_)
return false;
js_memcpy(filename_, filename, len);
return true;
}
bool
ScriptSource::setSourceMap(JSContext *cx, jschar *sourceMapURL, const char *filename)
{
JS_ASSERT(sourceMapURL);
if (hasSourceMap()) {
if (!JS_ReportErrorFlagsAndNumber(cx, JSREPORT_WARNING, js_GetErrorMessage, NULL,
JSMSG_ALREADY_HAS_SOURCEMAP, filename)) {
js_free(sourceMapURL);
return false;
}
}
sourceMap_ = sourceMapURL;
return true;
}
const jschar *
ScriptSource::sourceMap()
{
JS_ASSERT(hasSourceMap());
return sourceMap_;
}
/*
* Shared script data management.
*/
SharedScriptData *
js::SharedScriptData::new_(JSContext *cx, uint32_t codeLength,
uint32_t srcnotesLength, uint32_t natoms)
{
TRACK_MEMORY_SCOPE("Javascript");
uint32_t baseLength = codeLength + srcnotesLength;
uint32_t padding = sizeof(JSAtom *) - baseLength % sizeof(JSAtom *);
uint32_t length = baseLength + padding + sizeof(JSAtom *) * natoms;
SharedScriptData *entry = (SharedScriptData *)cx->malloc_(length +
offsetof(SharedScriptData, data));
if (!entry)
return NULL;
entry->marked = false;
entry->length = length;
memset(entry->data + baseLength, 0, padding);
return entry;
}
bool
js::SaveSharedScriptData(JSContext *cx, Handle<JSScript *> script, SharedScriptData *ssd)
{
ASSERT(script != NULL);
ASSERT(ssd != NULL);
JSRuntime *rt = cx->runtime();
ScriptBytecodeHasher::Lookup l(ssd);
ScriptDataTable::AddPtr p = rt->scriptDataTable.lookupForAdd(l);
if (p) {
js_free(ssd);
ssd = *p;
} else {
if (!rt->scriptDataTable.add(p, ssd)) {
js_free(ssd);
JS_ReportOutOfMemory(cx);
return false;
}
}
#ifdef JSGC_INCREMENTAL
/*
* During the IGC we need to ensure that bytecode is marked whenever it is
* accessed even if the bytecode was already in the table: at this point
* old scripts or exceptions pointing to the bytecode may no longer be
* reachable. This is effectively a read barrier.
*/
if (JS::IsIncrementalGCInProgress(rt) && rt->gcIsFull)
ssd->marked = true;
#endif
script->code = ssd->data;
script->atoms = ssd->atoms(script->length, script->numNotes());
return true;
}
void
js::SweepScriptData(JSRuntime *rt)
{
JS_ASSERT(rt->gcIsFull);
ScriptDataTable &table = rt->scriptDataTable;
for (ScriptDataTable::Enum e(table); !e.empty(); e.popFront()) {
SharedScriptData *entry = e.front();
if (entry->marked) {
entry->marked = false;
} else if (!rt->gcKeepAtoms) {
js_free(entry);
e.removeFront();
}
}
}
void
js::FreeScriptData(JSRuntime *rt)
{
ScriptDataTable &table = rt->scriptDataTable;
if (!table.initialized())
return;
for (ScriptDataTable::Enum e(table); !e.empty(); e.popFront())
js_free(e.front());
table.clear();
}
/*
* JSScript::data and SharedScriptData::data have complex,
* manually-controlled, memory layouts.
*
* JSScript::data begins with some optional array headers. They are optional
* because they often aren't needed, i.e. the corresponding arrays often have
* zero elements. Each header has a bit in JSScript::hasArrayBits that
* indicates if it's present within |data|; from this the offset of each
* present array header can be computed. Each header has an accessor function
* in JSScript that encapsulates this offset computation.
*
* Array type Array elements Accessor
* ---------- -------------- --------
* ConstArray Consts consts()
* ObjectArray Objects objects()
* ObjectArray Regexps regexps()
* TryNoteArray Try notes trynotes()
*
* Then are the elements of several arrays.
* - Most of these arrays have headers listed above (if present). For each of
* these, the array pointer and the array length is stored in the header.
* - The remaining arrays have pointers and lengths that are stored directly in
* JSScript. This is because, unlike the others, they are nearly always
* non-zero length and so the optional-header space optimization isn't
* worthwhile.
*
* Array elements Pointed to by Length
* -------------- ------------- ------
* Consts consts()->vector consts()->length
* Objects objects()->vector objects()->length
* Regexps regexps()->vector regexps()->length
* Try notes trynotes()->vector trynotes()->length
*
* IMPORTANT: This layout has two key properties.
* - It ensures that everything has sufficient alignment; in particular, the
* consts() elements need jsval alignment.
* - It ensures there are no gaps between elements, which saves space and makes
* manual layout easy. In particular, in the second part, arrays with larger
* elements precede arrays with smaller elements.
*
* SharedScriptData::data contains data that can be shared within a
* runtime. These items' layout is manually controlled to make it easier to
* manage both during (temporary) allocation and during matching against
* existing entries in the runtime. As the jsbytecode has to come first to
* enable lookup by bytecode identity, SharedScriptData::data, the atoms part
* has to manually be aligned sufficiently by adding padding after the notes
* part.
*
* Array elements Pointed to by Length
* -------------- ------------- ------
* jsbytecode code length
* jsscrnote notes() numNotes()
* Atoms atoms natoms
*
* The following static assertions check JSScript::data's alignment properties.
*/
#define KEEPS_JSVAL_ALIGNMENT(T) \
(JS_ALIGNMENT_OF(jsval) % JS_ALIGNMENT_OF(T) == 0 && \
sizeof(T) % sizeof(jsval) == 0)
#define HAS_JSVAL_ALIGNMENT(T) \
(JS_ALIGNMENT_OF(jsval) == JS_ALIGNMENT_OF(T) && \
sizeof(T) == sizeof(jsval))
#define NO_PADDING_BETWEEN_ENTRIES(T1, T2) \
(JS_ALIGNMENT_OF(T1) % JS_ALIGNMENT_OF(T2) == 0)
/*
* These assertions ensure that there is no padding between the array headers,
* and also that the consts() elements (which follow immediately afterward) are
* jsval-aligned. (There is an assumption that |data| itself is jsval-aligned;
* we check this below).
*/
JS_STATIC_ASSERT(KEEPS_JSVAL_ALIGNMENT(ConstArray));
JS_STATIC_ASSERT(KEEPS_JSVAL_ALIGNMENT(ObjectArray)); /* there are two of these */
JS_STATIC_ASSERT(KEEPS_JSVAL_ALIGNMENT(TryNoteArray));
/* These assertions ensure there is no padding required between array elements. */
JS_STATIC_ASSERT(HAS_JSVAL_ALIGNMENT(HeapValue));
JS_STATIC_ASSERT(NO_PADDING_BETWEEN_ENTRIES(HeapValue, HeapPtrObject));
JS_STATIC_ASSERT(NO_PADDING_BETWEEN_ENTRIES(HeapPtrObject, HeapPtrObject));
JS_STATIC_ASSERT(NO_PADDING_BETWEEN_ENTRIES(HeapPtrObject, JSTryNote));
JS_STATIC_ASSERT(NO_PADDING_BETWEEN_ENTRIES(JSTryNote, uint32_t));
JS_STATIC_ASSERT(NO_PADDING_BETWEEN_ENTRIES(uint32_t, uint32_t));
static inline size_t
ScriptDataSize(uint32_t nbindings, uint32_t nobjects, uint32_t nregexps,
uint32_t ntrynotes, uint32_t nconsts)
{
size_t size = 0;
if (nconsts != 0)
size += sizeof(ConstArray) + nconsts * sizeof(Value);
if (nobjects != 0)
size += sizeof(ObjectArray) + nobjects * sizeof(JSObject *);
if (nregexps != 0)
size += sizeof(ObjectArray) + nregexps * sizeof(JSObject *);
if (ntrynotes != 0)
size += sizeof(TryNoteArray) + ntrynotes * sizeof(JSTryNote);
if (nbindings != 0) {
// Make sure bindings are sufficiently aligned.
size = JS_ROUNDUP(size, JS_ALIGNMENT_OF(Binding)) + nbindings * sizeof(Binding);
}
return size;
}
JSScript *
JSScript::Create(JSContext *cx, HandleObject enclosingScope, bool savedCallerFun,
const CompileOptions &options, unsigned staticLevel,
JS::HandleScriptSource sourceObject, uint32_t bufStart, uint32_t bufEnd)
{
TRACK_MEMORY_SCOPE("Javascript");
JS_ASSERT(bufStart <= bufEnd);
RootedScript script(cx, js_NewGCScript(cx));
if (!script)
return NULL;
PodZero(script.get());
new (&script->bindings) Bindings;
script->enclosingScopeOrOriginalFunction_ = enclosingScope;
script->savedCallerFun = savedCallerFun;
script->compartment_ = cx->compartment();
/* Establish invariant: principals implies originPrincipals. */
if (options.principals) {
JS_ASSERT(options.principals == cx->compartment()->principals);
script->originPrincipals
= options.originPrincipals ? options.originPrincipals : options.principals;
JS_HoldPrincipals(script->originPrincipals);
} else if (options.originPrincipals) {
script->originPrincipals = options.originPrincipals;
JS_HoldPrincipals(script->originPrincipals);
}
script->compileAndGo = options.compileAndGo;
script->selfHosted = options.selfHostingMode;
script->noScriptRval = options.noScriptRval;
script->version = options.version;
JS_ASSERT(script->getVersion() == options.version); // assert that no overflow occurred
// This is an unsigned-to-uint16_t conversion, test for too-high values.
// In practice, recursion in Parser and/or BytecodeEmitter will blow the
// stack if we nest functions more than a few hundred deep, so this will
// never trigger. Oh well.
if (staticLevel > UINT16_MAX) {
JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_TOO_DEEP, js_function_str);
return NULL;
}
script->staticLevel = uint16_t(staticLevel);
script->sourceObject_ = sourceObject;
script->sourceStart = bufStart;
script->sourceEnd = bufEnd;
return script;
}
static inline uint8_t *
AllocScriptData(JSContext *cx, size_t size)
{
TRACK_MEMORY_SCOPE("Javascript");
uint8_t *data = static_cast<uint8_t *>(cx->calloc_(JS_ROUNDUP(size, sizeof(Value))));
if (!data)
return NULL;
// All script data is optional, so size might be 0. In that case, we don't care about alignment.
JS_ASSERT(size == 0 || size_t(data) % sizeof(Value) == 0);
return data;
}
/* static */ bool
JSScript::partiallyInit(JSContext *cx, Handle<JSScript*> script, uint32_t nobjects,
uint32_t nregexps, uint32_t ntrynotes, uint32_t nconsts, uint32_t nTypeSets)
{
TRACK_MEMORY_SCOPE("Javascript");
size_t size = ScriptDataSize(script->bindings.count(), nobjects, nregexps, ntrynotes, nconsts);
script->data = AllocScriptData(cx, size);
if (!script->data)
return false;
script->dataSize = size;
JS_ASSERT(nTypeSets <= UINT16_MAX);
script->nTypeSets = uint16_t(nTypeSets);
uint8_t *cursor = script->data;
if (nconsts != 0) {
script->setHasArray(CONSTS);
cursor += sizeof(ConstArray);
}
if (nobjects != 0) {
script->setHasArray(OBJECTS);
cursor += sizeof(ObjectArray);
}
if (nregexps != 0) {
script->setHasArray(REGEXPS);
cursor += sizeof(ObjectArray);
}
if (ntrynotes != 0) {
script->setHasArray(TRYNOTES);
cursor += sizeof(TryNoteArray);
}
if (nconsts != 0) {
JS_ASSERT(reinterpret_cast<uintptr_t>(cursor) % sizeof(jsval) == 0);
script->consts()->length = nconsts;
script->consts()->vector = (HeapValue *)cursor;
cursor += nconsts * sizeof(script->consts()->vector[0]);
}
if (nobjects != 0) {
script->objects()->length = nobjects;
script->objects()->vector = (HeapPtr<JSObject> *)cursor;
cursor += nobjects * sizeof(script->objects()->vector[0]);
}
if (nregexps != 0) {
script->regexps()->length = nregexps;
script->regexps()->vector = (HeapPtr<JSObject> *)cursor;
cursor += nregexps * sizeof(script->regexps()->vector[0]);
}
if (ntrynotes != 0) {
script->trynotes()->length = ntrynotes;
script->trynotes()->vector = reinterpret_cast<JSTryNote *>(cursor);
size_t vectorSize = ntrynotes * sizeof(script->trynotes()->vector[0]);
#ifdef DEBUG
memset(cursor, 0, vectorSize);
#endif
cursor += vectorSize;
}
if (script->bindings.count() != 0) {
// Make sure bindings are sufficiently aligned.
cursor = reinterpret_cast<uint8_t*>
(JS_ROUNDUP(reinterpret_cast<uintptr_t>(cursor), JS_ALIGNMENT_OF(Binding)));
}
cursor = script->bindings.switchToScriptStorage(reinterpret_cast<Binding *>(cursor));
JS_ASSERT(cursor == script->data + size);
return true;
}
/* static */ bool
JSScript::fullyInitTrivial(JSContext *cx, Handle<JSScript*> script)
{
TRACK_MEMORY_SCOPE("Javascript");
if (!partiallyInit(cx, script, 0, 0, 0, 0, 0))
return false;
SharedScriptData *ssd = SharedScriptData::new_(cx, 1, 1, 0);
if (!ssd)
return false;
ssd->data[0] = JSOP_STOP;
ssd->data[1] = SRC_NULL;
script->length = 1;
return SaveSharedScriptData(cx, script, ssd);
}
/* static */ bool
JSScript::fullyInitFromEmitter(JSContext *cx, Handle<JSScript*> script, BytecodeEmitter *bce)
{
TRACK_MEMORY_SCOPE("Javascript");
/* The counts of indexed things must be checked during code generation. */
JS_ASSERT(bce->atomIndices->count() <= INDEX_LIMIT);
JS_ASSERT(bce->objectList.length <= INDEX_LIMIT);
JS_ASSERT(bce->regexpList.length <= INDEX_LIMIT);
uint32_t mainLength = bce->offset();
uint32_t prologLength = bce->prologOffset();
uint32_t nsrcnotes = uint32_t(bce->countFinalSourceNotes());
uint32_t natoms = bce->atomIndices->count();
if (!partiallyInit(cx, script,
bce->objectList.length, bce->regexpList.length, bce->tryNoteList.length(),
bce->constList.length(), bce->typesetCount))
{
return false;
}
JS_ASSERT(script->mainOffset == 0);
script->mainOffset = prologLength;
script->lineno = bce->firstLine;
script->length = prologLength + mainLength;
script->natoms = natoms;
SharedScriptData *ssd = SharedScriptData::new_(cx, script->length, nsrcnotes, natoms);
if (!ssd)
return false;
jsbytecode *code = ssd->data;
PodCopy<jsbytecode>(code, bce->prolog.code.begin(), prologLength);
PodCopy<jsbytecode>(code + prologLength, bce->code().begin(), mainLength);
if (!FinishTakingSrcNotes(cx, bce, (jssrcnote *)(code + script->length)))
return false;
InitAtomMap(cx, bce->atomIndices.getMap(), ssd->atoms(script->length, nsrcnotes));
if (!SaveSharedScriptData(cx, script, ssd))
return false;
uint32_t nfixed = bce->sc->isFunctionBox() ? script->bindings.numVars() : 0;
JS_ASSERT(nfixed < SLOTNO_LIMIT);
script->nfixed = uint16_t(nfixed);
if (script->nfixed + bce->maxStackDepth >= JS_BIT(16)) {
bce->reportError(NULL, JSMSG_NEED_DIET, "script");
return false;
}
script->nslots = script->nfixed + bce->maxStackDepth;
FunctionBox *funbox = bce->sc->isFunctionBox() ? bce->sc->asFunctionBox() : NULL;
if (bce->tryNoteList.length() != 0)
bce->tryNoteList.finish(script->trynotes());
if (bce->objectList.length != 0)
bce->objectList.finish(script->objects());
if (bce->regexpList.length != 0)
bce->regexpList.finish(script->regexps());
if (bce->constList.length() != 0)
bce->constList.finish(script->consts());
script->strict = bce->sc->strict;
script->explicitUseStrict = bce->sc->hasExplicitUseStrict();
script->bindingsAccessedDynamically = bce->sc->bindingsAccessedDynamically();
script->funHasExtensibleScope = funbox ? funbox->hasExtensibleScope() : false;
script->funNeedsDeclEnvObject = funbox ? funbox->needsDeclEnvObject() : false;
script->hasSingletons = bce->hasSingletons;
if (funbox) {
if (funbox->argumentsHasLocalBinding()) {
// This must precede the script->bindings.transfer() call below
script->setArgumentsHasVarBinding();
if (funbox->definitelyNeedsArgsObj())
script->setNeedsArgsObj(true);
} else {
JS_ASSERT(!funbox->definitelyNeedsArgsObj());
}
script->ndefaults = funbox->ndefaults;
}
RootedFunction fun(cx, NULL);
if (funbox) {
JS_ASSERT(!bce->script->noScriptRval);
script->isGenerator = funbox->isGenerator();
script->isGeneratorExp = funbox->inGenexpLambda;
script->setFunction(funbox->function());
}
/*
* initScriptCounts updates scriptCountsMap if necessary. The other script
* maps in JSCompartment are populated lazily.
*/
if (cx->hasOption(JSOPTION_PCCOUNT))
(void) script->initScriptCounts(cx);
for (unsigned i = 0, n = script->bindings.numArgs(); i < n; ++i) {
if (script->formalIsAliased(i)) {
script->funHasAnyAliasedFormal = true;
break;
}
}
return true;
}
size_t
JSScript::computedSizeOfData()
{
return dataSize;
}
size_t
JSScript::sizeOfData(JSMallocSizeOfFun mallocSizeOf)
{
return mallocSizeOf(data);
}
/*
* Nb: srcnotes are variable-length. This function computes the number of
* srcnote *slots*, which may be greater than the number of srcnotes.
*/
uint32_t
JSScript::numNotes()
{
jssrcnote *sn;
jssrcnote *notes_ = notes();
for (sn = notes_; !SN_IS_TERMINATOR(sn); sn = SN_NEXT(sn))
continue;
return sn - notes_ + 1; /* +1 for the terminator */
}
bool
JSScript::isShortRunning()
{
return length < 100 &&
hasAnalysis() &&
!analysis()->hasFunctionCalls();
}
bool
JSScript::enclosingScriptsCompiledSuccessfully() const
{
/*
* When a nested script is succesfully compiled, it is eagerly given the
* static JSFunction of its enclosing script. The enclosing function's
* 'script' field will be NULL until the enclosing script successfully
* compiles. Thus, we can detect failed compilation by looking for
* JSFunctions in the enclosingScope chain without scripts.
*/
JSObject *enclosing = enclosingStaticScope();
while (enclosing) {
if (enclosing->is<JSFunction>()) {
JSFunction *fun = &enclosing->as<JSFunction>();
if (!fun->hasScript() || !fun->nonLazyScript())
return false;
enclosing = fun->nonLazyScript()->enclosingStaticScope();
} else {
enclosing = enclosing->as<StaticBlockObject>().enclosingStaticScope();
}
}
return true;
}
void
js::CallNewScriptHook(JSContext *cx, HandleScript script, HandleFunction fun)
{
if (script->selfHosted)
return;
JS_ASSERT(!script->isActiveEval);
if (JSNewScriptHook hook = cx->runtime()->debugHooks.newScriptHook) {
AutoKeepAtoms keep(cx->runtime());
hook(cx, script->filename(), script->lineno, script, fun,
cx->runtime()->debugHooks.newScriptHookData);
}
}
void
js::CallDestroyScriptHook(FreeOp *fop, JSScript *script)
{
if (script->selfHosted)
return;
// The hook will only call into JS if a GC is not running.
if (JSDestroyScriptHook hook = fop->runtime()->debugHooks.destroyScriptHook)
hook(fop, script, fop->runtime()->debugHooks.destroyScriptHookData);
script->clearTraps(fop);
}
void
JSScript::finalize(FreeOp *fop)
{
// NOTE: this JSScript may be partially initialized at this point. E.g. we
// may have created it and partially initialized it with
// JSScript::Create(), but not yet finished initializing it with
// fullyInitFromEmitter() or fullyInitTrivial().
CallDestroyScriptHook(fop, this);
fop->runtime()->spsProfiler.onScriptFinalized(this);
if (originPrincipals)
JS_DropPrincipals(fop->runtime(), originPrincipals);
if (types)
types->destroy();
#ifdef JS_ION
jit::DestroyIonScripts(fop, this);
#endif
destroyScriptCounts(fop);
destroyDebugScript(fop);
if (data) {
JS_POISON(data, 0xdb, computedSizeOfData());
fop->free_(data);
}
fop->runtime()->lazyScriptCache.remove(this);
}
static const uint32_t GSN_CACHE_THRESHOLD = 100;
static const uint32_t GSN_CACHE_MAP_INIT_SIZE = 20;
void
GSNCache::purge()
{
code = NULL;
if (map.initialized())
map.finish();
}
jssrcnote *
js_GetSrcNote(JSContext *cx, JSScript *script, jsbytecode *pc)
{
GSNCache *cache = &cx->runtime()->gsnCache;
cx = NULL; // nulling |cx| ensures GC can't be triggered, so |JSScript *script| is safe
size_t target = pc - script->code;
if (target >= size_t(script->length))
return NULL;
if (cache->code == script->code) {
JS_ASSERT(cache->map.initialized());
GSNCache::Map::Ptr p = cache->map.lookup(pc);
return p ? p->value : NULL;
}
size_t offset = 0;
jssrcnote *result;
for (jssrcnote *sn = script->notes(); ; sn = SN_NEXT(sn)) {
if (SN_IS_TERMINATOR(sn)) {
result = NULL;
break;
}
offset += SN_DELTA(sn);
if (offset == target && SN_IS_GETTABLE(sn)) {
result = sn;
break;
}
}
if (cache->code != script->code && script->length >= GSN_CACHE_THRESHOLD) {
unsigned nsrcnotes = 0;
for (jssrcnote *sn = script->notes(); !SN_IS_TERMINATOR(sn);
sn = SN_NEXT(sn)) {
if (SN_IS_GETTABLE(sn))
++nsrcnotes;
}
if (cache->code) {
JS_ASSERT(cache->map.initialized());
cache->map.finish();
cache->code = NULL;
}
if (cache->map.init(nsrcnotes)) {
pc = script->code;
for (jssrcnote *sn = script->notes(); !SN_IS_TERMINATOR(sn);
sn = SN_NEXT(sn)) {
pc += SN_DELTA(sn);
if (SN_IS_GETTABLE(sn))
JS_ALWAYS_TRUE(cache->map.put(pc, sn));
}
cache->code = script->code;
}
}
return result;
}
unsigned
js::PCToLineNumber(unsigned startLine, jssrcnote *notes, jsbytecode *code, jsbytecode *pc,
unsigned *columnp)
{
unsigned lineno = startLine;
unsigned column = 0;
/*
* Walk through source notes accumulating their deltas, keeping track of
* line-number notes, until we pass the note for pc's offset within
* script->code.
*/
ptrdiff_t offset = 0;
ptrdiff_t target = pc - code;
for (jssrcnote *sn = notes; !SN_IS_TERMINATOR(sn); sn = SN_NEXT(sn)) {
offset += SN_DELTA(sn);
SrcNoteType type = (SrcNoteType) SN_TYPE(sn);
if (type == SRC_SETLINE) {
if (offset <= target)
lineno = (unsigned) js_GetSrcNoteOffset(sn, 0);
column = 0;
} else if (type == SRC_NEWLINE) {
if (offset <= target)
lineno++;
column = 0;
}
if (offset > target)
break;
if (type == SRC_COLSPAN) {
ptrdiff_t colspan = js_GetSrcNoteOffset(sn, 0);
if (colspan >= SN_COLSPAN_DOMAIN / 2)
colspan -= SN_COLSPAN_DOMAIN;
JS_ASSERT(ptrdiff_t(column) + colspan >= 0);
column += colspan;
}
}
if (columnp)
*columnp = column;
return lineno;
}
unsigned
js::PCToLineNumber(JSScript *script, jsbytecode *pc, unsigned *columnp)
{
/* Cope with StackFrame.pc value prior to entering js_Interpret. */
if (!pc)
return 0;
return PCToLineNumber(script->lineno, script->notes(), script->code, pc, columnp);
}
/* The line number limit is the same as the jssrcnote offset limit. */
#define SN_LINE_LIMIT (SN_3BYTE_OFFSET_FLAG << 16)
jsbytecode *
js_LineNumberToPC(JSScript *script, unsigned target)
{
ptrdiff_t offset = 0;
ptrdiff_t best = -1;
unsigned lineno = script->lineno;
unsigned bestdiff = SN_LINE_LIMIT;
for (jssrcnote *sn = script->notes(); !SN_IS_TERMINATOR(sn); sn = SN_NEXT(sn)) {
/*
* Exact-match only if offset is not in the prolog; otherwise use
* nearest greater-or-equal line number match.
*/
if (lineno == target && offset >= ptrdiff_t(script->mainOffset))
goto out;
if (lineno >= target) {
unsigned diff = lineno - target;
if (diff < bestdiff) {
bestdiff = diff;
best = offset;
}
}
offset += SN_DELTA(sn);
SrcNoteType type = (SrcNoteType) SN_TYPE(sn);
if (type == SRC_SETLINE) {
lineno = (unsigned) js_GetSrcNoteOffset(sn, 0);
} else if (type == SRC_NEWLINE) {
lineno++;
}
}
if (best >= 0)
offset = best;
out:
return script->code + offset;
}
JS_FRIEND_API(unsigned)
js_GetScriptLineExtent(JSScript *script)
{
unsigned lineno = script->lineno;
unsigned maxLineNo = 0;
bool counting = true;
for (jssrcnote *sn = script->notes(); !SN_IS_TERMINATOR(sn); sn = SN_NEXT(sn)) {
SrcNoteType type = (SrcNoteType) SN_TYPE(sn);
if (type == SRC_SETLINE) {
if (maxLineNo < lineno)
maxLineNo = lineno;
lineno = (unsigned) js_GetSrcNoteOffset(sn, 0);
counting = true;
if (maxLineNo < lineno)
maxLineNo = lineno;
else
counting = false;
} else if (type == SRC_NEWLINE) {
if (counting)
lineno++;
}
}
if (maxLineNo > lineno)
lineno = maxLineNo;
return 1 + lineno - script->lineno;
}
void
js::CurrentScriptFileLineOriginSlow(JSContext *cx, const char **file, unsigned *linenop,
JSPrincipals **origin)
{
NonBuiltinScriptFrameIter iter(cx);
if (iter.done()) {
*file = NULL;
*linenop = 0;
*origin = NULL;
return;
}
JSScript *script = iter.script();
*file = script->filename();
*linenop = PCToLineNumber(iter.script(), iter.pc());
*origin = script->originPrincipals;
}
template <class T>
static inline T *
Rebase(JSScript *dst, JSScript *src, T *srcp)
{
size_t off = reinterpret_cast<uint8_t *>(srcp) - src->data;
return reinterpret_cast<T *>(dst->data + off);
}
JSScript *
js::CloneScript(JSContext *cx, HandleObject enclosingScope, HandleFunction fun, HandleScript src,
NewObjectKind newKind /* = GenericObject */)
{
/* NB: Keep this in sync with XDRScript. */
uint32_t nconsts = src->hasConsts() ? src->consts()->length : 0;
uint32_t nobjects = src->hasObjects() ? src->objects()->length : 0;
uint32_t nregexps = src->hasRegexps() ? src->regexps()->length : 0;
uint32_t ntrynotes = src->hasTrynotes() ? src->trynotes()->length : 0;
/* Script data */
size_t size = src->dataSize;
uint8_t *data = AllocScriptData(cx, size);
if (!data)
return NULL;
/* Bindings */
Rooted<Bindings> bindings(cx);
InternalHandle<Bindings*> bindingsHandle =
InternalHandle<Bindings*>::fromMarkedLocation(bindings.address());
if (!Bindings::clone(cx, bindingsHandle, data, src))
return NULL;
/* Objects */
AutoObjectVector objects(cx);
if (nobjects != 0) {
HeapPtrObject *vector = src->objects()->vector;
for (unsigned i = 0; i < nobjects; i++) {
RootedObject obj(cx, vector[i]);
RootedObject clone(cx);
if (obj->is<StaticBlockObject>()) {
Rooted<StaticBlockObject*> innerBlock(cx, &obj->as<StaticBlockObject>());
RootedObject enclosingScope(cx);
if (StaticBlockObject *enclosingBlock = innerBlock->enclosingBlock())
enclosingScope = objects[FindBlockIndex(src, *enclosingBlock)];
else
enclosingScope = fun;
clone = CloneStaticBlockObject(cx, enclosingScope, innerBlock);
} else if (obj->is<JSFunction>()) {
RootedFunction innerFun(cx, &obj->as<JSFunction>());
if (innerFun->isNative()) {
assertSameCompartment(cx, innerFun);
clone = innerFun;
} else {
if (innerFun->isInterpretedLazy()) {
AutoCompartment ac(cx, innerFun);
if (!innerFun->getOrCreateScript(cx))
return NULL;
}
RootedObject staticScope(cx, innerFun->nonLazyScript()->enclosingStaticScope());
StaticScopeIter ssi(cx, staticScope);
RootedObject enclosingScope(cx);
if (!ssi.done() && ssi.type() == StaticScopeIter::BLOCK)
enclosingScope = objects[FindBlockIndex(src, ssi.block())];
else
enclosingScope = fun;
clone = CloneFunctionAndScript(cx, enclosingScope, innerFun);
}
} else {
/*
* Clone object literals emitted for the JSOP_NEWOBJECT opcode. We only emit that
* instead of the less-optimized JSOP_NEWINIT for self-hosted code or code compiled
* with JSOPTION_COMPILE_N_GO set. As we don't clone the latter type of code, this
* case should only ever be hit when cloning objects from self-hosted code.
*/
clone = CloneObjectLiteral(cx, cx->global(), obj);
}
if (!clone || !objects.append(clone))
return NULL;
}
}
/* RegExps */
AutoObjectVector regexps(cx);
for (unsigned i = 0; i < nregexps; i++) {
HeapPtrObject *vector = src->regexps()->vector;
for (unsigned i = 0; i < nregexps; i++) {
JSObject *clone = CloneScriptRegExpObject(cx, vector[i]->as<RegExpObject>());
if (!clone || !regexps.append(clone))
return NULL;
}
}
/* Now that all fallible allocation is complete, create the GC thing. */
CompileOptions options(cx);
options.setPrincipals(cx->compartment()->principals)
.setOriginPrincipals(src->originPrincipals)
.setCompileAndGo(src->compileAndGo)
.setSelfHostingMode(src->selfHosted)
.setNoScriptRval(src->noScriptRval)
.setVersion(src->getVersion());
/* Make sure we clone the script source object with the script */
JS::RootedScriptSource sourceObject(cx, ScriptSourceObject::create(cx, src->scriptSource()));
if (!sourceObject)
return NULL;
RootedScript dst(cx, JSScript::Create(cx, enclosingScope, src->savedCallerFun,
options, src->staticLevel,
sourceObject, src->sourceStart, src->sourceEnd));
if (!dst) {
js_free(data);
return NULL;
}
dst->bindings = bindings;
/* This assignment must occur before all the Rebase calls. */
dst->data = data;
dst->dataSize = size;
memcpy(data, src->data, size);
/* Script filenames, bytecodes and atoms are runtime-wide. */
dst->code = src->code;
dst->atoms = src->atoms;
dst->length = src->length;
dst->lineno = src->lineno;
dst->mainOffset = src->mainOffset;
dst->natoms = src->natoms;
dst->nfixed = src->nfixed;
dst->nTypeSets = src->nTypeSets;
dst->nslots = src->nslots;
if (src->argumentsHasVarBinding()) {
dst->setArgumentsHasVarBinding();
if (src->analyzedArgsUsage())
dst->setNeedsArgsObj(src->needsArgsObj());
}
dst->cloneHasArray(src);
dst->strict = src->strict;
dst->explicitUseStrict = src->explicitUseStrict;
dst->bindingsAccessedDynamically = src->bindingsAccessedDynamically;
dst->funHasExtensibleScope = src->funHasExtensibleScope;
dst->funNeedsDeclEnvObject = src->funNeedsDeclEnvObject;
dst->funHasAnyAliasedFormal = src->funHasAnyAliasedFormal;
dst->hasSingletons = src->hasSingletons;
dst->isGenerator = src->isGenerator;
dst->isGeneratorExp = src->isGeneratorExp;
/* Copy over hints. */
dst->shouldCloneAtCallsite = src->shouldCloneAtCallsite;
dst->isCallsiteClone = src->isCallsiteClone;
/*
* initScriptCounts updates scriptCountsMap if necessary. The other script
* maps in JSCompartment are populated lazily.
*/
if (cx->hasOption(JSOPTION_PCCOUNT))
(void) dst->initScriptCounts(cx);
if (nconsts != 0) {
HeapValue *vector = Rebase<HeapValue>(dst, src, src->consts()->vector);
dst->consts()->vector = vector;
for (unsigned i = 0; i < nconsts; ++i)
JS_ASSERT_IF(vector[i].isMarkable(), vector[i].toString()->isAtom());
}
if (nobjects != 0) {
HeapPtrObject *vector = Rebase<HeapPtr<JSObject> >(dst, src, src->objects()->vector);
dst->objects()->vector = vector;
for (unsigned i = 0; i < nobjects; ++i)
vector[i].init(objects[i]);
}
if (nregexps != 0) {
HeapPtrObject *vector = Rebase<HeapPtr<JSObject> >(dst, src, src->regexps()->vector);
dst->regexps()->vector = vector;
for (unsigned i = 0; i < nregexps; ++i)
vector[i].init(regexps[i]);
}
if (ntrynotes != 0)
dst->trynotes()->vector = Rebase<JSTryNote>(dst, src, src->trynotes()->vector);
return dst;
}
bool
js::CloneFunctionScript(JSContext *cx, HandleFunction original, HandleFunction clone,
NewObjectKind newKind /* = GenericObject */)
{
JS_ASSERT(clone->isInterpreted());
RootedScript script(cx, clone->nonLazyScript());
JS_ASSERT(script);
JS_ASSERT(script->compartment() == original->compartment());
JS_ASSERT_IF(script->compartment() != cx->compartment(),
!script->enclosingStaticScope());
RootedObject scope(cx, script->enclosingStaticScope());
clone->mutableScript().init(NULL);
JSScript *cscript = CloneScript(cx, scope, clone, script, newKind);
if (!cscript)
return false;
clone->setScript(cscript);
cscript->setFunction(clone);
RootedGlobalObject global(cx, script->compileAndGo ? &script->global() : NULL);
script = clone->nonLazyScript();
CallNewScriptHook(cx, script, clone);
Debugger::onNewScript(cx, script, global);
return true;
}
DebugScript *
JSScript::debugScript()
{
JS_ASSERT(hasDebugScript);
DebugScriptMap *map = compartment()->debugScriptMap;
JS_ASSERT(map);
DebugScriptMap::Ptr p = map->lookup(this);
JS_ASSERT(p);
return p->value;
}
DebugScript *
JSScript::releaseDebugScript()
{
JS_ASSERT(hasDebugScript);
DebugScriptMap *map = compartment()->debugScriptMap;
JS_ASSERT(map);
DebugScriptMap::Ptr p = map->lookup(this);
JS_ASSERT(p);
DebugScript *debug = p->value;
map->remove(p);
hasDebugScript = false;
return debug;
}
void
JSScript::destroyDebugScript(FreeOp *fop)
{
if (hasDebugScript) {
jsbytecode *end = code + length;
for (jsbytecode *pc = code; pc < end; pc++) {
if (BreakpointSite *site = getBreakpointSite(pc)) {
/* Breakpoints are swept before finalization. */
JS_ASSERT(site->firstBreakpoint() == NULL);
site->clearTrap(fop, NULL, NULL);
JS_ASSERT(getBreakpointSite(pc) == NULL);
}
}
fop->free_(releaseDebugScript());
}
}
bool
JSScript::ensureHasDebugScript(JSContext *cx)
{
if (hasDebugScript)
return true;
size_t nbytes = offsetof(DebugScript, breakpoints) + length * sizeof(BreakpointSite*);
DebugScript *debug = (DebugScript *) cx->calloc_(nbytes);
if (!debug)
return false;
/* Create compartment's debugScriptMap if necessary. */
DebugScriptMap *map = compartment()->debugScriptMap;
if (!map) {
map = cx->new_<DebugScriptMap>();
if (!map || !map->init()) {
js_free(debug);
js_delete(map);
return false;
}
compartment()->debugScriptMap = map;
}
if (!map->putNew(this, debug)) {
js_free(debug);
return false;
}
hasDebugScript = true; // safe to set this; we can't fail after this point
/*
* Ensure that any Interpret() instances running on this script have
* interrupts enabled. The interrupts must stay enabled until the
* debug state is destroyed.
*/
InterpreterFrames *frames;
for (frames = cx->runtime()->interpreterFrames; frames; frames = frames->older)
frames->enableInterruptsIfRunning(this);
return true;
}
void
JSScript::recompileForStepMode(FreeOp *fop)
{
#ifdef JS_ION
if (hasBaselineScript())
baseline->toggleDebugTraps(this, NULL);
#endif
}
bool
JSScript::tryNewStepMode(JSContext *cx, uint32_t newValue)
{
JS_ASSERT(hasDebugScript);
DebugScript *debug = debugScript();
uint32_t prior = debug->stepMode;
debug->stepMode = newValue;
if (!prior != !newValue) {
/* Step mode has been enabled or disabled. Alert the methodjit. */
recompileForStepMode(cx->runtime()->defaultFreeOp());
if (!stepModeEnabled() && !debug->numSites)
js_free(releaseDebugScript());
}
return true;
}
bool
JSScript::setStepModeFlag(JSContext *cx, bool step)
{
if (!ensureHasDebugScript(cx))
return false;
return tryNewStepMode(cx, (debugScript()->stepMode & stepCountMask) |
(step ? stepFlagMask : 0));
}
bool
JSScript::changeStepModeCount(JSContext *cx, int delta)
{
if (!ensureHasDebugScript(cx))
return false;
assertSameCompartment(cx, this);
JS_ASSERT_IF(delta > 0, cx->compartment()->debugMode());
DebugScript *debug = debugScript();
uint32_t count = debug->stepMode & stepCountMask;
JS_ASSERT(((count + delta) & stepCountMask) == count + delta);
return tryNewStepMode(cx,
(debug->stepMode & stepFlagMask) |
((count + delta) & stepCountMask));
}
BreakpointSite *
JSScript::getOrCreateBreakpointSite(JSContext *cx, jsbytecode *pc)
{
JS_ASSERT(size_t(pc - code) < length);
if (!ensureHasDebugScript(cx))
return NULL;
DebugScript *debug = debugScript();
BreakpointSite *&site = debug->breakpoints[pc - code];
if (!site) {
site = cx->runtime()->new_<BreakpointSite>(this, pc);
if (!site) {
js_ReportOutOfMemory(cx);
return NULL;
}
debug->numSites++;
}
return site;
}
void
JSScript::destroyBreakpointSite(FreeOp *fop, jsbytecode *pc)
{
JS_ASSERT(unsigned(pc - code) < length);
DebugScript *debug = debugScript();
BreakpointSite *&site = debug->breakpoints[pc - code];
JS_ASSERT(site);
fop->delete_(site);
site = NULL;
if (--debug->numSites == 0 && !stepModeEnabled())
fop->free_(releaseDebugScript());
}
void
JSScript::clearBreakpointsIn(FreeOp *fop, js::Debugger *dbg, JSObject *handler)
{
if (!hasAnyBreakpointsOrStepMode())
return;
jsbytecode *end = code + length;
for (jsbytecode *pc = code; pc < end; pc++) {
BreakpointSite *site = getBreakpointSite(pc);
if (site) {
Breakpoint *nextbp;
for (Breakpoint *bp = site->firstBreakpoint(); bp; bp = nextbp) {
nextbp = bp->nextInSite();
if ((!dbg || bp->debugger == dbg) && (!handler || bp->getHandler() == handler))
bp->destroy(fop);
}
}
}
}
bool
JSScript::hasBreakpointsAt(jsbytecode *pc)
{
BreakpointSite *site = getBreakpointSite(pc);
if (!site)
return false;
return site->enabledCount > 0 || site->trapHandler;
}
void
JSScript::clearTraps(FreeOp *fop)
{
if (!hasAnyBreakpointsOrStepMode())
return;
jsbytecode *end = code + length;
for (jsbytecode *pc = code; pc < end; pc++) {
BreakpointSite *site = getBreakpointSite(pc);
if (site)
site->clearTrap(fop);
}
}
void
JSScript::markChildren(JSTracer *trc)
{
// NOTE: this JSScript may be partially initialized at this point. E.g. we
// may have created it and partially initialized it with
// JSScript::Create(), but not yet finished initializing it with
// fullyInitFromEmitter() or fullyInitTrivial().
JS_ASSERT_IF(trc->runtime->gcStrictCompartmentChecking, zone()->isCollecting());
for (uint32_t i = 0; i < natoms; ++i) {
if (atoms[i])
MarkString(trc, &atoms[i], "atom");
}
if (hasObjects()) {
ObjectArray *objarray = objects();
MarkObjectRange(trc, objarray->length, objarray->vector, "objects");
}
if (hasRegexps()) {
ObjectArray *objarray = regexps();
MarkObjectRange(trc, objarray->length, objarray->vector, "objects");
}
if (hasConsts()) {
ConstArray *constarray = consts();
MarkValueRange(trc, constarray->length, constarray->vector, "consts");
}
if (sourceObject())
MarkObject(trc, &sourceObject_, "sourceObject");
if (function())
MarkObject(trc, &function_, "function");
if (enclosingScopeOrOriginalFunction_)
MarkObject(trc, &enclosingScopeOrOriginalFunction_, "enclosing");
if (IS_GC_MARKING_TRACER(trc)) {
compartment()->mark();
if (code)
MarkScriptBytecode(trc->runtime, code);
}
bindings.trace(trc);
if (hasAnyBreakpointsOrStepMode()) {
for (unsigned i = 0; i < length; i++) {
BreakpointSite *site = debugScript()->breakpoints[i];
if (site && site->trapHandler)
MarkValue(trc, &site->trapClosure, "trap closure");
}
}
#ifdef JS_ION
jit::TraceIonScripts(trc, this);
#endif
}
void
LazyScript::markChildren(JSTracer *trc)
{
if (function_)
MarkObject(trc, &function_, "function");
if (sourceObject_)
MarkObject(trc, &sourceObject_, "sourceObject");
if (enclosingScope_)
MarkObject(trc, &enclosingScope_, "enclosingScope");
if (script_)
MarkScript(trc, &script_, "realScript");
HeapPtrAtom *freeVariables = this->freeVariables();
for (size_t i = 0; i < numFreeVariables(); i++)
MarkString(trc, &freeVariables[i], "lazyScriptFreeVariable");
HeapPtrFunction *innerFunctions = this->innerFunctions();
for (size_t i = 0; i < numInnerFunctions(); i++)
MarkObject(trc, &innerFunctions[i], "lazyScriptInnerFunction");
}
void
LazyScript::finalize(FreeOp *fop)
{
if (table_)
fop->free_(table_);
if (originPrincipals_)
JS_DropPrincipals(fop->runtime(), originPrincipals_);
}
void
JSScript::setArgumentsHasVarBinding()
{
argsHasVarBinding_ = true;
needsArgsAnalysis_ = true;
}
void
JSScript::setNeedsArgsObj(bool needsArgsObj)
{
JS_ASSERT(!analyzedArgsUsage());
JS_ASSERT_IF(needsArgsObj, argumentsHasVarBinding());
needsArgsAnalysis_ = false;
needsArgsObj_ = needsArgsObj;
}
void
js::SetFrameArgumentsObject(JSContext *cx, AbstractFramePtr frame,
HandleScript script, JSObject *argsobj)
{
/*
* Replace any optimized arguments in the frame with an explicit arguments
* object. Note that 'arguments' may have already been overwritten.
*/
InternalBindingsHandle bindings(script, &script->bindings);
const unsigned var = Bindings::argumentsVarIndex(cx, bindings);
if (script->varIsAliased(var)) {
/*
* Scan the script to find the slot in the call object that 'arguments'
* is assigned to.
*/
jsbytecode *pc = script->code;
while (*pc != JSOP_ARGUMENTS)
pc += GetBytecodeLength(pc);
pc += JSOP_ARGUMENTS_LENGTH;
JS_ASSERT(*pc == JSOP_SETALIASEDVAR);
if (frame.callObj().as<ScopeObject>().aliasedVar(pc).isMagic(JS_OPTIMIZED_ARGUMENTS))
frame.callObj().as<ScopeObject>().setAliasedVar(cx, pc, cx->names().arguments, ObjectValue(*argsobj));
} else {
if (frame.unaliasedLocal(var).isMagic(JS_OPTIMIZED_ARGUMENTS))
frame.unaliasedLocal(var) = ObjectValue(*argsobj);
}
}
/* static */ bool
JSScript::argumentsOptimizationFailed(JSContext *cx, HandleScript script)
{
JS_ASSERT(script->function());
JS_ASSERT(script->analyzedArgsUsage());
JS_ASSERT(script->argumentsHasVarBinding());
/*
* It is possible that the arguments optimization has already failed,
* everything has been fixed up, but there was an outstanding magic value
* on the stack that has just now flowed into an apply. In this case, there
* is nothing to do; GuardFunApplySpeculation will patch in the real
* argsobj.
*/
if (script->needsArgsObj())
return true;
JS_ASSERT(!script->isGenerator);
script->needsArgsObj_ = true;
#ifdef JS_ION
/*
* Since we can't invalidate baseline scripts, set a flag that's checked from
* JIT code to indicate the arguments optimization failed and JSOP_ARGUMENTS
* should create an arguments object next time.
*/
if (script->hasBaselineScript())
script->baselineScript()->setNeedsArgsObj();
#endif
/*
* By design, the arguments optimization is only made when there are no
* outstanding cases of MagicValue(JS_OPTIMIZED_ARGUMENTS) at any points
* where the optimization could fail, other than an active invocation of
* 'f.apply(x, arguments)'. Thus, there are no outstanding values of
* MagicValue(JS_OPTIMIZED_ARGUMENTS) on the stack. However, there are
* three things that need fixup:
* - there may be any number of activations of this script that don't have
* an argsObj that now need one.
* - jit code compiled (and possible active on the stack) with the static
* assumption of !script->needsArgsObj();
* - type inference data for the script assuming script->needsArgsObj
*/
for (AllFramesIter i(cx); !i.done(); ++i) {
/*
* We cannot reliably create an arguments object for Ion activations of
* this script. To maintain the invariant that "script->needsArgsObj
* implies fp->hasArgsObj", the Ion bail mechanism will create an
* arguments object right after restoring the StackFrame and before
* entering the interpreter (in jit::ThunkToInterpreter). This delay is
* safe since the engine avoids any observation of a StackFrame when it's
* runningInJit (see ScriptFrameIter::interpFrame comment).
*/
if (i.isIon())
continue;
AbstractFramePtr frame = i.abstractFramePtr();
if (frame.isFunctionFrame() && frame.script() == script) {
ArgumentsObject *argsobj = ArgumentsObject::createExpected(cx, frame);
if (!argsobj) {
/*
* We can't leave stack frames with script->needsArgsObj but no
* arguments object. It is, however, safe to leave frames with
* an arguments object but !script->needsArgsObj.
*/
script->needsArgsObj_ = false;
return false;
}
SetFrameArgumentsObject(cx, frame, script, argsobj);
}
}
if (script->hasAnalysis() && script->analysis()->ranInference()) {
types::AutoEnterAnalysis enter(cx);
types::TypeScript::MonitorUnknown(cx, script, script->argumentsBytecode());
}
return true;
}
bool
JSScript::varIsAliased(unsigned varSlot)
{
return bindings.bindingIsAliased(bindings.numArgs() + varSlot);
}
bool
JSScript::formalIsAliased(unsigned argSlot)
{
return bindings.bindingIsAliased(argSlot);
}
bool
JSScript::formalLivesInArgumentsObject(unsigned argSlot)
{
return argsObjAliasesFormals() && !formalIsAliased(argSlot);
}
LazyScript::LazyScript(JSFunction *fun, void *table, uint32_t numFreeVariables, uint32_t numInnerFunctions,
JSVersion version, uint32_t begin, uint32_t end, uint32_t lineno, uint32_t column)
: script_(NULL),
function_(fun),
enclosingScope_(NULL),
sourceObject_(NULL),
table_(table),
originPrincipals_(NULL),
version_(version),
numFreeVariables_(numFreeVariables),
numInnerFunctions_(numInnerFunctions),
strict_(false),
bindingsAccessedDynamically_(false),
hasDebuggerStatement_(false),
directlyInsideEval_(false),
usesArgumentsAndApply_(false),
hasBeenCloned_(false),
begin_(begin),
end_(end),
lineno_(lineno),
column_(column)
{
JS_ASSERT(this->version() == version);
JS_ASSERT(begin <= end);
}
void
LazyScript::initScript(JSScript *script)
{
JS_ASSERT(script && !script_);
script_ = script;
}
void
LazyScript::setParent(JSObject *enclosingScope, ScriptSourceObject *sourceObject,
JSPrincipals *originPrincipals)
{
JS_ASSERT(sourceObject && !sourceObject_ && !enclosingScope_ && !originPrincipals_);
enclosingScope_ = enclosingScope;
sourceObject_ = sourceObject;
originPrincipals_ = originPrincipals;
if (originPrincipals)
JS_HoldPrincipals(originPrincipals);
}
ScriptSourceObject *
LazyScript::sourceObject() const
{
return sourceObject_ ? &sourceObject_->as<ScriptSourceObject>() : NULL;
}
/* static */ LazyScript *
LazyScript::Create(JSContext *cx, HandleFunction fun,
uint32_t numFreeVariables, uint32_t numInnerFunctions, JSVersion version,
uint32_t begin, uint32_t end, uint32_t lineno, uint32_t column)
{
JS_ASSERT(begin <= end);
size_t bytes = (numFreeVariables * sizeof(HeapPtrAtom))
+ (numInnerFunctions * sizeof(HeapPtrFunction));
void *table = NULL;
if (bytes) {
table = cx->malloc_(bytes);
if (!table)
return NULL;
}
LazyScript *res = js_NewGCLazyScript(cx);
if (!res)
return NULL;
return new (res) LazyScript(fun, table, numFreeVariables, numInnerFunctions, version,
begin, end, lineno, column);
}
uint32_t
LazyScript::staticLevel(JSContext *cx) const
{
for (StaticScopeIter ssi(cx, enclosingScope()); !ssi.done(); ssi++) {
if (ssi.type() == StaticScopeIter::FUNCTION)
return ssi.funScript()->staticLevel + 1;
}
return 1;
}
void
JSScript::updateBaselineOrIonRaw()
{
#ifdef JS_ION
if (hasIonScript()) {
baselineOrIonRaw = ion->method()->raw();
baselineOrIonSkipArgCheck = ion->method()->raw() + ion->getSkipArgCheckEntryOffset();
} else if (hasBaselineScript()) {
baselineOrIonRaw = baseline->method()->raw();
baselineOrIonSkipArgCheck = baseline->method()->raw();
} else {
baselineOrIonRaw = NULL;
baselineOrIonSkipArgCheck = NULL;
}
#endif
}
static inline void
LazyScriptHash(uint32_t lineno, uint32_t column, uint32_t begin, uint32_t end,
HashNumber hashes[3])
{
HashNumber hash = lineno;
hash = JS_ROTATE_LEFT32(hash, 4) ^ column;
hash = JS_ROTATE_LEFT32(hash, 4) ^ begin;
hash = JS_ROTATE_LEFT32(hash, 4) ^ end;
hashes[0] = hash;
hashes[1] = JS_ROTATE_LEFT32(hashes[0], 4) ^ begin;
hashes[2] = JS_ROTATE_LEFT32(hashes[1], 4) ^ end;
}
void
LazyScriptHashPolicy::hash(const Lookup &lookup, HashNumber hashes[3])
{
LazyScript *lazy = lookup.lazy;
LazyScriptHash(lazy->lineno(), lazy->column(), lazy->begin(), lazy->end(), hashes);
}
void
LazyScriptHashPolicy::hash(JSScript *script, HashNumber hashes[3])
{
LazyScriptHash(script->lineno, script->column, script->sourceStart, script->sourceEnd, hashes);
}
bool
LazyScriptHashPolicy::match(JSScript *script, const Lookup &lookup)
{
JSContext *cx = lookup.cx;
LazyScript *lazy = lookup.lazy;
// To be a match, the script and lazy script need to have the same line
// and column and to be at the same position within their respective
// source blobs, and to have the same source contents and version.
//
// While the surrounding code in the source may differ, this is
// sufficient to ensure that compiling the lazy script will yield an
// identical result to compiling the original script.
//
// Note that the filenames and origin principals of the lazy script and
// original script can differ. If there is a match, these will be fixed
// up in the resulting clone by the caller.
if (script->lineno != lazy->lineno() ||
script->column != lazy->column() ||
script->getVersion() != lazy->version() ||
script->sourceStart != lazy->begin() ||
script->sourceEnd != lazy->end())
{
return false;
}
// GC activity may destroy the character pointers being compared below.
AutoSuppressGC suppress(cx);
const jschar *scriptChars = script->scriptSource()->chars(cx);
if (!scriptChars)
return false;
const jschar *lazyChars = lazy->source()->chars(cx);
if (!lazyChars)
return false;
size_t begin = script->sourceStart;
size_t length = script->sourceEnd - begin;
return !memcmp(scriptChars + begin, lazyChars + begin, length);
}