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JSScript.cpp
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JSScript.cpp
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* 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 "vm/JSScript-inl.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/Maybe.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/PodOperations.h"
#include "mozilla/ScopeExit.h"
#include "mozilla/Sprintf.h"
#include "mozilla/Unused.h"
#include "mozilla/Vector.h"
#include <algorithm>
#include <new>
#include <string.h>
#include <type_traits>
#include <utility>
#include "jsapi.h"
#include "jstypes.h"
#include "jsutil.h"
#include "frontend/BytecodeCompiler.h"
#include "frontend/BytecodeEmitter.h"
#include "frontend/SharedContext.h"
#include "gc/FreeOp.h"
#include "jit/BaselineJIT.h"
#include "jit/Ion.h"
#include "jit/IonCode.h"
#include "jit/JitRealm.h"
#include "js/CompileOptions.h"
#include "js/MemoryMetrics.h"
#include "js/Printf.h"
#include "js/SourceText.h"
#include "js/UniquePtr.h"
#include "js/Utility.h"
#include "js/Wrapper.h"
#include "util/StringBuffer.h"
#include "util/Text.h"
#include "vm/ArgumentsObject.h"
#include "vm/BytecodeIterator.h"
#include "vm/BytecodeLocation.h"
#include "vm/BytecodeUtil.h"
#include "vm/Compression.h"
#include "vm/Debugger.h"
#include "vm/JSAtom.h"
#include "vm/JSContext.h"
#include "vm/JSFunction.h"
#include "vm/JSObject.h"
#include "vm/Opcodes.h"
#include "vm/SelfHosting.h"
#include "vm/Shape.h"
#include "vm/SharedImmutableStringsCache.h"
#include "vm/Xdr.h"
#include "vtune/VTuneWrapper.h"
#include "gc/Marking-inl.h"
#include "vm/BytecodeIterator-inl.h"
#include "vm/BytecodeLocation-inl.h"
#include "vm/Compartment-inl.h"
#include "vm/EnvironmentObject-inl.h"
#include "vm/JSFunction-inl.h"
#include "vm/JSObject-inl.h"
#include "vm/NativeObject-inl.h"
#include "vm/SharedImmutableStringsCache-inl.h"
#include "vm/Stack-inl.h"
using namespace js;
using mozilla::Maybe;
using mozilla::PodCopy;
using mozilla::PointerRangeSize;
using mozilla::Utf8AsUnsignedChars;
using mozilla::Utf8Unit;
using JS::CompileOptions;
using JS::ReadOnlyCompileOptions;
using JS::SourceText;
template <XDRMode mode>
XDRResult js::XDRScriptConst(XDRState<mode>* xdr, MutableHandleValue vp) {
JSContext* cx = xdr->cx();
enum ConstTag {
SCRIPT_INT,
SCRIPT_DOUBLE,
SCRIPT_ATOM,
SCRIPT_TRUE,
SCRIPT_FALSE,
SCRIPT_NULL,
SCRIPT_OBJECT,
SCRIPT_VOID,
SCRIPT_HOLE,
SCRIPT_BIGINT
};
ConstTag 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 if (vp.isObject()) {
tag = SCRIPT_OBJECT;
} else if (vp.isMagic(JS_ELEMENTS_HOLE)) {
tag = SCRIPT_HOLE;
} else if (vp.isBigInt()) {
tag = SCRIPT_BIGINT;
} else {
MOZ_ASSERT(vp.isUndefined());
tag = SCRIPT_VOID;
}
}
MOZ_TRY(xdr->codeEnum32(&tag));
switch (tag) {
case SCRIPT_INT: {
uint32_t i;
if (mode == XDR_ENCODE) {
i = uint32_t(vp.toInt32());
}
MOZ_TRY(xdr->codeUint32(&i));
if (mode == XDR_DECODE) {
vp.set(Int32Value(int32_t(i)));
}
break;
}
case SCRIPT_DOUBLE: {
double d;
if (mode == XDR_ENCODE) {
d = vp.toDouble();
}
MOZ_TRY(xdr->codeDouble(&d));
if (mode == XDR_DECODE) {
vp.set(DoubleValue(d));
}
break;
}
case SCRIPT_ATOM: {
RootedAtom atom(cx);
if (mode == XDR_ENCODE) {
atom = &vp.toString()->asAtom();
}
MOZ_TRY(XDRAtom(xdr, &atom));
if (mode == XDR_DECODE) {
vp.set(StringValue(atom));
}
break;
}
case SCRIPT_TRUE:
if (mode == XDR_DECODE) {
vp.set(BooleanValue(true));
}
break;
case SCRIPT_FALSE:
if (mode == XDR_DECODE) {
vp.set(BooleanValue(false));
}
break;
case SCRIPT_NULL:
if (mode == XDR_DECODE) {
vp.set(NullValue());
}
break;
case SCRIPT_OBJECT: {
RootedObject obj(cx);
if (mode == XDR_ENCODE) {
obj = &vp.toObject();
}
MOZ_TRY(XDRObjectLiteral(xdr, &obj));
if (mode == XDR_DECODE) {
vp.setObject(*obj);
}
break;
}
case SCRIPT_VOID:
if (mode == XDR_DECODE) {
vp.set(UndefinedValue());
}
break;
case SCRIPT_HOLE:
if (mode == XDR_DECODE) {
vp.setMagic(JS_ELEMENTS_HOLE);
}
break;
case SCRIPT_BIGINT: {
RootedBigInt bi(cx);
if (mode == XDR_ENCODE) {
bi = vp.toBigInt();
}
MOZ_TRY(XDRBigInt(xdr, &bi));
if (mode == XDR_DECODE) {
vp.setBigInt(bi);
}
break;
}
default:
// Fail in debug, but only soft-fail in release
MOZ_ASSERT(false, "Bad XDR value kind");
return xdr->fail(JS::TranscodeResult_Failure_BadDecode);
}
return Ok();
}
template XDRResult js::XDRScriptConst(XDRState<XDR_ENCODE>*,
MutableHandleValue);
template XDRResult js::XDRScriptConst(XDRState<XDR_DECODE>*,
MutableHandleValue);
// Code LazyScript's closed over bindings.
template <XDRMode mode>
static XDRResult XDRLazyClosedOverBindings(XDRState<mode>* xdr,
MutableHandle<LazyScript*> lazy) {
JSContext* cx = xdr->cx();
RootedAtom atom(cx);
for (size_t i = 0; i < lazy->numClosedOverBindings(); i++) {
uint8_t endOfScopeSentinel;
if (mode == XDR_ENCODE) {
atom = lazy->closedOverBindings()[i];
endOfScopeSentinel = !atom;
}
MOZ_TRY(xdr->codeUint8(&endOfScopeSentinel));
if (endOfScopeSentinel) {
atom = nullptr;
} else {
MOZ_TRY(XDRAtom(xdr, &atom));
}
if (mode == XDR_DECODE) {
lazy->closedOverBindings()[i] = atom;
}
}
return Ok();
}
// Code the missing part needed to re-create a LazyScript from a JSScript.
template <XDRMode mode>
static XDRResult XDRRelazificationInfo(XDRState<mode>* xdr, HandleFunction fun,
HandleScript script,
HandleScope enclosingScope,
MutableHandle<LazyScript*> lazy) {
MOZ_ASSERT_IF(mode == XDR_ENCODE, script->isRelazifiableIgnoringJitCode() &&
script->maybeLazyScript());
MOZ_ASSERT_IF(mode == XDR_ENCODE, !lazy->numInnerFunctions());
JSContext* cx = xdr->cx();
uint64_t packedFields;
{
uint32_t sourceStart = script->sourceStart();
uint32_t sourceEnd = script->sourceEnd();
uint32_t toStringStart = script->toStringStart();
uint32_t toStringEnd = script->toStringEnd();
uint32_t lineno = script->lineno();
uint32_t column = script->column();
uint32_t numFieldInitializers;
if (mode == XDR_ENCODE) {
packedFields = lazy->packedFieldsForXDR();
MOZ_ASSERT(sourceStart == lazy->sourceStart());
MOZ_ASSERT(sourceEnd == lazy->sourceEnd());
MOZ_ASSERT(toStringStart == lazy->toStringStart());
MOZ_ASSERT(toStringEnd == lazy->toStringEnd());
MOZ_ASSERT(lineno == lazy->lineno());
MOZ_ASSERT(column == lazy->column());
// We can assert we have no inner functions because we don't
// relazify scripts with inner functions. See
// JSFunction::createScriptForLazilyInterpretedFunction.
MOZ_ASSERT(lazy->numInnerFunctions() == 0);
if (fun->kind() == JSFunction::FunctionKind::ClassConstructor) {
numFieldInitializers =
(uint32_t)lazy->getFieldInitializers().numFieldInitializers;
} else {
numFieldInitializers = UINT32_MAX;
}
}
MOZ_TRY(xdr->codeUint64(&packedFields));
MOZ_TRY(xdr->codeUint32(&numFieldInitializers));
if (mode == XDR_DECODE) {
RootedScriptSourceObject sourceObject(cx, script->sourceObject());
lazy.set(LazyScript::CreateForXDR(
cx, fun, script, enclosingScope, sourceObject, packedFields,
sourceStart, sourceEnd, toStringStart, lineno, column));
if (!lazy) {
return xdr->fail(JS::TranscodeResult_Throw);
}
lazy->setToStringEnd(toStringEnd);
if (numFieldInitializers != UINT32_MAX) {
lazy->setFieldInitializers(
FieldInitializers((size_t)numFieldInitializers));
}
}
}
// Code binding names.
MOZ_TRY(XDRLazyClosedOverBindings(xdr, lazy));
// No need to do anything with inner functions, since we asserted we don't
// have any.
return Ok();
}
template <XDRMode mode>
XDRResult JSTryNote::XDR(XDRState<mode>* xdr) {
MOZ_TRY(xdr->codeUint32(&kind));
MOZ_TRY(xdr->codeUint32(&stackDepth));
MOZ_TRY(xdr->codeUint32(&start));
MOZ_TRY(xdr->codeUint32(&length));
return Ok();
}
template <XDRMode mode>
XDRResult ScopeNote::XDR(XDRState<mode>* xdr) {
MOZ_TRY(xdr->codeUint32(&index));
MOZ_TRY(xdr->codeUint32(&start));
MOZ_TRY(xdr->codeUint32(&length));
MOZ_TRY(xdr->codeUint32(&parent));
return Ok();
}
static inline uint32_t FindScopeIndex(mozilla::Span<const GCPtrScope> scopes,
Scope& scope) {
unsigned length = scopes.size();
for (uint32_t i = 0; i < length; ++i) {
if (scopes[i] == &scope) {
return i;
}
}
MOZ_CRASH("Scope not found");
}
template <XDRMode mode>
static XDRResult XDRInnerObject(XDRState<mode>* xdr,
js::PrivateScriptData* data,
HandleScriptSourceObject sourceObject,
MutableHandleObject inner) {
enum class ClassKind { RegexpObject, JSFunction, JSObject, ArrayObject };
JSContext* cx = xdr->cx();
ClassKind classk;
if (mode == XDR_ENCODE) {
if (inner->is<RegExpObject>()) {
classk = ClassKind::RegexpObject;
} else if (inner->is<JSFunction>()) {
classk = ClassKind::JSFunction;
} else if (inner->is<PlainObject>()) {
classk = ClassKind::JSObject;
} else if (inner->is<ArrayObject>()) {
classk = ClassKind::ArrayObject;
} else {
MOZ_CRASH("Cannot encode this class of object.");
}
}
MOZ_TRY(xdr->codeEnum32(&classk));
switch (classk) {
case ClassKind::RegexpObject: {
Rooted<RegExpObject*> regexp(cx);
if (mode == XDR_ENCODE) {
regexp = &inner->as<RegExpObject>();
}
MOZ_TRY(XDRScriptRegExpObject(xdr, ®exp));
if (mode == XDR_DECODE) {
inner.set(regexp);
}
break;
}
case ClassKind::JSFunction: {
/* Code the nested function's enclosing scope. */
uint32_t funEnclosingScopeIndex = 0;
RootedScope funEnclosingScope(cx);
if (mode == XDR_ENCODE) {
RootedFunction function(cx, &inner->as<JSFunction>());
if (function->isInterpretedLazy()) {
funEnclosingScope = function->lazyScript()->enclosingScope();
} else if (function->isInterpreted()) {
funEnclosingScope = function->nonLazyScript()->enclosingScope();
} else {
MOZ_ASSERT(function->isAsmJSNative());
return xdr->fail(JS::TranscodeResult_Failure_AsmJSNotSupported);
}
funEnclosingScopeIndex =
FindScopeIndex(data->scopes(), *funEnclosingScope);
}
MOZ_TRY(xdr->codeUint32(&funEnclosingScopeIndex));
if (mode == XDR_DECODE) {
funEnclosingScope = data->scopes()[funEnclosingScopeIndex];
}
// Code nested function and script.
RootedFunction tmp(cx);
if (mode == XDR_ENCODE) {
tmp = &inner->as<JSFunction>();
}
MOZ_TRY(
XDRInterpretedFunction(xdr, funEnclosingScope, sourceObject, &tmp));
if (mode == XDR_DECODE) {
inner.set(tmp);
}
break;
}
case ClassKind::JSObject:
case ClassKind::ArrayObject: {
/* Code object literal. */
RootedObject tmp(cx);
if (mode == XDR_ENCODE) {
tmp = inner.get();
}
MOZ_TRY(XDRObjectLiteral(xdr, &tmp));
if (mode == XDR_DECODE) {
inner.set(tmp);
}
break;
}
default: {
// Fail in debug, but only soft-fail in release
MOZ_ASSERT(false, "Bad XDR class kind");
return xdr->fail(JS::TranscodeResult_Failure_BadDecode);
}
}
return Ok();
}
template <XDRMode mode>
static XDRResult XDRScope(XDRState<mode>* xdr, js::PrivateScriptData* data,
HandleScope scriptEnclosingScope, HandleFunction fun,
uint32_t scopeIndex, MutableHandleScope scope) {
JSContext* cx = xdr->cx();
ScopeKind scopeKind;
RootedScope enclosing(cx);
uint32_t enclosingIndex = 0;
// The enclosingScope is encoded using an integer index into the scope array.
// This means that scopes must be topologically sorted.
if (mode == XDR_ENCODE) {
scopeKind = scope->kind();
if (scopeIndex == 0) {
enclosingIndex = UINT32_MAX;
} else {
MOZ_ASSERT(scope->enclosing());
enclosingIndex = FindScopeIndex(data->scopes(), *scope->enclosing());
}
}
MOZ_TRY(xdr->codeEnum32(&scopeKind));
MOZ_TRY(xdr->codeUint32(&enclosingIndex));
if (mode == XDR_DECODE) {
if (scopeIndex == 0) {
MOZ_ASSERT(enclosingIndex == UINT32_MAX);
enclosing = scriptEnclosingScope;
} else {
MOZ_ASSERT(enclosingIndex < scopeIndex);
enclosing = data->scopes()[enclosingIndex];
}
}
switch (scopeKind) {
case ScopeKind::Function:
MOZ_TRY(FunctionScope::XDR(xdr, fun, enclosing, scope));
break;
case ScopeKind::FunctionBodyVar:
case ScopeKind::ParameterExpressionVar:
MOZ_TRY(VarScope::XDR(xdr, scopeKind, enclosing, scope));
break;
case ScopeKind::Lexical:
case ScopeKind::SimpleCatch:
case ScopeKind::Catch:
case ScopeKind::NamedLambda:
case ScopeKind::StrictNamedLambda:
MOZ_TRY(LexicalScope::XDR(xdr, scopeKind, enclosing, scope));
break;
case ScopeKind::With:
MOZ_TRY(WithScope::XDR(xdr, enclosing, scope));
break;
case ScopeKind::Eval:
case ScopeKind::StrictEval:
MOZ_TRY(EvalScope::XDR(xdr, scopeKind, enclosing, scope));
break;
case ScopeKind::Global:
case ScopeKind::NonSyntactic:
MOZ_TRY(GlobalScope::XDR(xdr, scopeKind, scope));
break;
case ScopeKind::Module:
case ScopeKind::WasmInstance:
MOZ_CRASH("NYI");
break;
case ScopeKind::WasmFunction:
MOZ_CRASH("wasm functions cannot be nested in JSScripts");
break;
default:
// Fail in debug, but only soft-fail in release
MOZ_ASSERT(false, "Bad XDR scope kind");
return xdr->fail(JS::TranscodeResult_Failure_BadDecode);
}
return Ok();
}
template <XDRMode mode>
/* static */
XDRResult js::PrivateScriptData::XDR(XDRState<mode>* xdr, HandleScript script,
HandleScriptSourceObject sourceObject,
HandleScope scriptEnclosingScope,
HandleFunction fun) {
uint32_t nscopes = 0;
uint32_t nconsts = 0;
uint32_t nobjects = 0;
uint32_t ntrynotes = 0;
uint32_t nscopenotes = 0;
uint32_t nresumeoffsets = 0;
JSContext* cx = xdr->cx();
PrivateScriptData* data = nullptr;
if (mode == XDR_ENCODE) {
data = script->data_;
nscopes = data->scopes().size();
if (data->hasConsts()) {
nconsts = data->consts().size();
}
if (data->hasObjects()) {
nobjects = data->objects().size();
}
if (data->hasTryNotes()) {
ntrynotes = data->tryNotes().size();
}
if (data->hasScopeNotes()) {
nscopenotes = data->scopeNotes().size();
}
if (data->hasResumeOffsets()) {
nresumeoffsets = data->resumeOffsets().size();
}
}
MOZ_TRY(xdr->codeUint32(&nscopes));
MOZ_TRY(xdr->codeUint32(&nconsts));
MOZ_TRY(xdr->codeUint32(&nobjects));
MOZ_TRY(xdr->codeUint32(&ntrynotes));
MOZ_TRY(xdr->codeUint32(&nscopenotes));
MOZ_TRY(xdr->codeUint32(&nresumeoffsets));
if (mode == XDR_DECODE) {
if (!JSScript::createPrivateScriptData(cx, script, nscopes, nconsts,
nobjects, ntrynotes, nscopenotes,
nresumeoffsets)) {
return xdr->fail(JS::TranscodeResult_Throw);
}
data = script->data_;
}
if (nconsts) {
RootedValue val(cx);
for (GCPtrValue& elem : data->consts()) {
if (mode == XDR_ENCODE) {
val = elem.get();
}
MOZ_TRY(XDRScriptConst(xdr, &val));
if (mode == XDR_DECODE) {
elem.init(val);
}
}
}
{
MOZ_ASSERT(nscopes > 0);
GCPtrScope* vector = data->scopes().data();
for (uint32_t i = 0; i < nscopes; ++i) {
RootedScope scope(cx);
if (mode == XDR_ENCODE) {
scope = vector[i];
}
MOZ_TRY(XDRScope(xdr, data, scriptEnclosingScope, fun, i, &scope));
if (mode == XDR_DECODE) {
vector[i].init(scope);
}
}
// Verify marker to detect data corruption after decoding scope data. A
// mismatch here indicates we will almost certainly crash in release.
MOZ_TRY(xdr->codeMarker(0x48922BAB));
}
/*
* Here looping from 0-to-length to xdr objects is essential to ensure that
* all references to enclosing blocks (via FindScopeIndex below) happen
* after the enclosing block has been XDR'd.
*/
if (nobjects) {
for (GCPtrObject& elem : data->objects()) {
RootedObject inner(cx);
if (mode == XDR_ENCODE) {
inner = elem;
}
MOZ_TRY(XDRInnerObject(xdr, data, sourceObject, &inner));
if (mode == XDR_DECODE) {
elem.init(inner);
}
}
}
// Verify marker to detect data corruption after decoding object data. A
// mismatch here indicates we will almost certainly crash in release.
MOZ_TRY(xdr->codeMarker(0xF83B989A));
if (ntrynotes) {
for (JSTryNote& elem : data->tryNotes()) {
MOZ_TRY(elem.XDR(xdr));
}
}
if (nscopenotes) {
for (ScopeNote& elem : data->scopeNotes()) {
MOZ_TRY(elem.XDR(xdr));
}
}
if (nresumeoffsets) {
for (uint32_t& elem : data->resumeOffsets()) {
MOZ_TRY(xdr->codeUint32(&elem));
}
}
return Ok();
}
// Placement-new elements of an array. This should optimize away for types with
// trivial default initiation.
template <typename T>
static void DefaultInitializeElements(void* arrayPtr, size_t length) {
uintptr_t elem = reinterpret_cast<uintptr_t>(arrayPtr);
MOZ_ASSERT(elem % alignof(T) == 0);
for (size_t i = 0; i < length; ++i) {
new (reinterpret_cast<void*>(elem)) T;
elem += sizeof(T);
}
}
/* static */ size_t SharedScriptData::AllocationSize(uint32_t codeLength,
uint32_t noteLength,
uint32_t natoms) {
size_t size = sizeof(SharedScriptData);
size += natoms * sizeof(GCPtrAtom);
size += codeLength * sizeof(jsbytecode);
size += noteLength * sizeof(jssrcnote);
return size;
}
// Placement-new elements of an array. This should optimize away for types with
// trivial default initiation.
template <typename T>
void SharedScriptData::initElements(size_t offset, size_t length) {
uintptr_t base = reinterpret_cast<uintptr_t>(this);
DefaultInitializeElements<T>(reinterpret_cast<void*>(base + offset), length);
}
SharedScriptData::SharedScriptData(uint32_t codeLength, uint32_t noteLength,
uint32_t natoms)
: codeLength_(codeLength), noteLength_(noteLength), natoms_(natoms) {
// Variable-length data begins immediately after SharedScriptData itself.
size_t cursor = sizeof(*this);
// Default-initialize trailing arrays.
static_assert(alignof(SharedScriptData) >= alignof(GCPtrAtom),
"Incompatible alignment");
initElements<GCPtrAtom>(cursor, natoms);
cursor += natoms * sizeof(GCPtrAtom);
static_assert(alignof(GCPtrAtom) >= alignof(jsbytecode),
"Incompatible alignment");
initElements<jsbytecode>(cursor, codeLength);
cursor += codeLength * sizeof(jsbytecode);
static_assert(alignof(jsbytecode) >= alignof(jssrcnote),
"Incompatible alignment");
initElements<jssrcnote>(cursor, noteLength);
cursor += noteLength * sizeof(jssrcnote);
// Sanity check
MOZ_ASSERT(AllocationSize(codeLength, noteLength, natoms) == cursor);
}
template <XDRMode mode>
/* static */
XDRResult SharedScriptData::XDR(XDRState<mode>* xdr, HandleScript script) {
uint32_t natoms = 0;
uint32_t codeLength = 0;
uint32_t noteLength = 0;
JSContext* cx = xdr->cx();
SharedScriptData* ssd = nullptr;
if (mode == XDR_ENCODE) {
ssd = script->scriptData();
natoms = ssd->natoms();
codeLength = ssd->codeLength();
noteLength = ssd->numNotes();
}
MOZ_TRY(xdr->codeUint32(&natoms));
MOZ_TRY(xdr->codeUint32(&codeLength));
MOZ_TRY(xdr->codeUint32(¬eLength));
if (mode == XDR_DECODE) {
if (!script->createSharedScriptData(cx, codeLength, noteLength, natoms)) {
return xdr->fail(JS::TranscodeResult_Throw);
}
ssd = script->scriptData();
}
JS_STATIC_ASSERT(sizeof(jsbytecode) == 1);
JS_STATIC_ASSERT(sizeof(jssrcnote) == 1);
jsbytecode* code = ssd->code();
jssrcnote* notes = ssd->notes();
MOZ_TRY(xdr->codeBytes(code, codeLength));
MOZ_TRY(xdr->codeBytes(notes, noteLength));
{
RootedAtom atom(cx);
GCPtrAtom* vector = ssd->atoms();
for (uint32_t i = 0; i != natoms; ++i) {
if (mode == XDR_ENCODE) {
atom = vector[i];
}
MOZ_TRY(XDRAtom(xdr, &atom));
if (mode == XDR_DECODE) {
vector[i].init(atom);
}
}
}
return Ok();
}
template
/* static */
XDRResult
SharedScriptData::XDR(XDRState<XDR_ENCODE>* xdr, HandleScript script);
template
/* static */
XDRResult
SharedScriptData::XDR(XDRState<XDR_DECODE>* xdr, HandleScript script);
template <XDRMode mode>
XDRResult js::XDRScript(XDRState<mode>* xdr, HandleScope scriptEnclosingScope,
HandleScriptSourceObject sourceObjectArg,
HandleFunction fun, MutableHandleScript scriptp) {
using ImmutableFlags = JSScript::ImmutableFlags;
/* NB: Keep this in sync with CopyScript. */
enum XDRScriptFlags {
OwnSource,
HasLazyScript,
};
uint8_t xdrScriptFlags = 0;
uint32_t lineno = 0;
uint32_t column = 0;
uint32_t mainOffset = 0;
uint32_t nfixed = 0;
uint32_t nslots = 0;
uint32_t bodyScopeIndex = 0;
uint32_t sourceStart = 0;
uint32_t sourceEnd = 0;
uint32_t toStringStart = 0;
uint32_t toStringEnd = 0;
uint32_t immutableFlags = 0;
uint16_t funLength = 0;
uint16_t numBytecodeTypeSets = 0;
// NOTE: |mutableFlags| are not preserved by XDR.
JSContext* cx = xdr->cx();
RootedScript script(cx);
if (mode == XDR_ENCODE) {
script = scriptp.get();
MOZ_ASSERT(script->functionNonDelazifying() == fun);
if (!fun && script->treatAsRunOnce() && script->hasRunOnce()) {
// This is a toplevel or eval script that's runOnce. We want to
// make sure that we're not XDR-saving an object we emitted for
// JSOP_OBJECT that then got modified. So throw if we're not
// cloning in JSOP_OBJECT or if we ever didn't clone in it in the
// past.
Realm* realm = cx->realm();
if (!realm->creationOptions().cloneSingletons() ||
!realm->behaviors().getSingletonsAsTemplates()) {
return xdr->fail(JS::TranscodeResult_Failure_RunOnceNotSupported);
}
}
if (!sourceObjectArg) {
xdrScriptFlags |= (1 << OwnSource);
}
if (script->isRelazifiableIgnoringJitCode()) {
xdrScriptFlags |= (1 << HasLazyScript);
}
}
MOZ_TRY(xdr->codeUint8(&xdrScriptFlags));
if (mode == XDR_ENCODE) {
lineno = script->lineno();
column = script->column();
mainOffset = script->mainOffset();
nfixed = script->nfixed();
nslots = script->nslots();
bodyScopeIndex = script->bodyScopeIndex();
sourceStart = script->sourceStart();
sourceEnd = script->sourceEnd();
toStringStart = script->toStringStart();
toStringEnd = script->toStringEnd();
immutableFlags = script->immutableFlags_;
funLength = script->funLength();
numBytecodeTypeSets = script->numBytecodeTypeSets();
}
MOZ_TRY(xdr->codeUint32(&lineno));
MOZ_TRY(xdr->codeUint32(&column));
MOZ_TRY(xdr->codeUint32(&mainOffset));
MOZ_TRY(xdr->codeUint32(&nfixed));
MOZ_TRY(xdr->codeUint32(&nslots));
MOZ_TRY(xdr->codeUint32(&bodyScopeIndex));
MOZ_TRY(xdr->codeUint32(&sourceStart));
MOZ_TRY(xdr->codeUint32(&sourceEnd));
MOZ_TRY(xdr->codeUint32(&toStringStart));
MOZ_TRY(xdr->codeUint32(&toStringEnd));
MOZ_TRY(xdr->codeUint32(&immutableFlags));
MOZ_TRY(xdr->codeUint16(&funLength));
MOZ_TRY(xdr->codeUint16(&numBytecodeTypeSets));
RootedScriptSourceObject sourceObject(cx, sourceObjectArg);
Maybe<CompileOptions> options;
if (mode == XDR_DECODE) {
// When loading from the bytecode cache, we get the CompileOptions from
// the document. If the noScriptRval or selfHostingMode flag doesn't
// match, we should fail. This only applies to the top-level and not
// its inner functions.
bool noScriptRval =
!!(immutableFlags & uint32_t(ImmutableFlags::NoScriptRval));
bool selfHosted = !!(immutableFlags & uint32_t(ImmutableFlags::SelfHosted));
if (xdr->hasOptions() && (xdrScriptFlags & (1 << OwnSource))) {
options.emplace(xdr->cx(), xdr->options());
if (options->noScriptRval != noScriptRval ||
options->selfHostingMode != selfHosted) {
return xdr->fail(JS::TranscodeResult_Failure_WrongCompileOption);
}
} else {
options.emplace(xdr->cx());
(*options).setNoScriptRval(noScriptRval).setSelfHostingMode(selfHosted);
}
}
if (xdrScriptFlags & (1 << OwnSource)) {
Rooted<ScriptSourceHolder> ssHolder(cx);
// We are relying on the script's ScriptSource so the caller should not
// have passed in an explicit one.
MOZ_ASSERT(sourceObjectArg == nullptr);
if (mode == XDR_ENCODE) {
sourceObject = script->sourceObject();
ssHolder.get().reset(sourceObject->source());
}
MOZ_TRY(ScriptSource::XDR(xdr, options, &ssHolder));
if (mode == XDR_DECODE) {
sourceObject = ScriptSourceObject::create(cx, ssHolder.get().get());
if (!sourceObject) {
return xdr->fail(JS::TranscodeResult_Throw);
}
if (xdr->hasScriptSourceObjectOut()) {
// When the ScriptSourceObjectOut is provided by ParseTask, it
// is stored in a location which is traced by the GC.
*xdr->scriptSourceObjectOut() = sourceObject;
} else if (!ScriptSourceObject::initFromOptions(cx, sourceObject,
*options)) {
return xdr->fail(JS::TranscodeResult_Throw);
}
}
} else {
// While encoding, the ScriptSource passed in must match the ScriptSource
// of the script.
MOZ_ASSERT_IF(mode == XDR_ENCODE,
sourceObjectArg->source() == script->scriptSource());
}
if (mode == XDR_DECODE) {
script = JSScript::Create(cx, *options, sourceObject, sourceStart,
sourceEnd, toStringStart, toStringEnd);
if (!script) {
return xdr->fail(JS::TranscodeResult_Throw);
}
scriptp.set(script);
script->lineno_ = lineno;
script->column_ = column;
script->mainOffset_ = mainOffset;
script->nfixed_ = nfixed;
script->nslots_ = nslots;
script->bodyScopeIndex_ = bodyScopeIndex;
script->immutableFlags_ = immutableFlags;
script->funLength_ = funLength;
script->numBytecodeTypeSets_ = numBytecodeTypeSets;
if (script->hasFlag(ImmutableFlags::ArgsHasVarBinding)) {
// Call setArgumentsHasVarBinding to initialize the
// NeedsArgsAnalysis flag.
script->setArgumentsHasVarBinding();
}
// Set the script in its function now so that inner scripts to be
// decoded may iterate the static scope chain.
if (fun) {
fun->initScript(script);
}
}
// If XDR operation fails, we must call JSScript::freeScriptData in order
// to neuter the script. Various things that iterate raw scripts in a GC
// arena use the presense of this data to detect if initialization is
// complete.
auto scriptDataGuard = mozilla::MakeScopeExit([&] {
if (mode == XDR_DECODE) {
script->freeScriptData();
}
});
// NOTE: The script data is rooted by the script.
MOZ_TRY(PrivateScriptData::XDR<mode>(xdr, script, sourceObject,
scriptEnclosingScope, fun));
MOZ_TRY(SharedScriptData::XDR<mode>(xdr, script));
if (mode == XDR_DECODE) {
if (!script->shareScriptData(cx)) {