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Mypal/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 "jsscriptinlines.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/MathAlgorithms.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 <string.h>
#include "jsapi.h"
#include "jsatom.h"
#include "jscntxt.h"
#include "jsfun.h"
#include "jsgc.h"
#include "jsobj.h"
#include "jsopcode.h"
#include "jsprf.h"
#include "jstypes.h"
#include "jsutil.h"
#include "jswrapper.h"
#include "frontend/BytecodeCompiler.h"
#include "frontend/BytecodeEmitter.h"
#include "frontend/SharedContext.h"
#include "gc/Marking.h"
#include "jit/BaselineJIT.h"
#include "jit/Ion.h"
#include "jit/IonCode.h"
#include "js/MemoryMetrics.h"
#include "js/Utility.h"
#include "vm/ArgumentsObject.h"
#include "vm/Compression.h"
#include "vm/Debugger.h"
#include "vm/Opcodes.h"
#include "vm/SelfHosting.h"
#include "vm/Shape.h"
#include "vm/SharedImmutableStringsCache.h"
#include "vm/Xdr.h"
#include "jsfuninlines.h"
#include "jsobjinlines.h"
#include "vm/EnvironmentObject-inl.h"
#include "vm/NativeObject-inl.h"
#include "vm/SharedImmutableStringsCache-inl.h"
#include "vm/Stack-inl.h"
using namespace js;
using namespace js::gc;
using namespace js::frontend;
using mozilla::AsVariant;
using mozilla::PodCopy;
using mozilla::PodZero;
using mozilla::RotateLeft;
template<XDRMode mode>
bool
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
};
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 {
MOZ_ASSERT(vp.isUndefined());
tag = SCRIPT_VOID;
}
}
if (!xdr->codeEnum32(&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 false;
if (mode == XDR_DECODE)
vp.set(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.set(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.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();
if (!XDRObjectLiteral(xdr, &obj))
return false;
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;
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 true;
}
template bool
js::XDRScriptConst(XDRState<XDR_ENCODE>*, MutableHandleValue);
template bool
js::XDRScriptConst(XDRState<XDR_DECODE>*, MutableHandleValue);
// Code LazyScript's closed over bindings.
template<XDRMode mode>
static bool
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;
}
if (!xdr->codeUint8(&endOfScopeSentinel))
return false;
if (endOfScopeSentinel)
atom = nullptr;
else if (!XDRAtom(xdr, &atom))
return false;
if (mode == XDR_DECODE)
lazy->closedOverBindings()[i] = atom;
}
return true;
}
// Code the missing part needed to re-create a LazyScript from a JSScript.
template<XDRMode mode>
static bool
XDRRelazificationInfo(XDRState<mode>* xdr, HandleFunction fun, HandleScript script,
HandleScope enclosingScope, MutableHandle<LazyScript*> lazy)
{
MOZ_ASSERT_IF(mode == XDR_ENCODE, script->isRelazifiable() && script->maybeLazyScript());
MOZ_ASSERT_IF(mode == XDR_ENCODE, !lazy->numInnerFunctions());
JSContext* cx = xdr->cx();
uint64_t packedFields;
{
uint32_t begin = script->sourceStart();
uint32_t end = script->sourceEnd();
uint32_t preludeStart = script->preludeStart();
uint32_t lineno = script->lineno();
uint32_t column = script->column();
if (mode == XDR_ENCODE) {
packedFields = lazy->packedFields();
MOZ_ASSERT(begin == lazy->begin());
MOZ_ASSERT(end == lazy->end());
MOZ_ASSERT(preludeStart == lazy->preludeStart());
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 (!xdr->codeUint64(&packedFields))
return false;
if (mode == XDR_DECODE) {
lazy.set(LazyScript::Create(cx, fun, script, enclosingScope, script,
packedFields, begin, end, preludeStart, lineno, column));
// As opposed to XDRLazyScript, we need to restore the runtime bits
// of the script, as we are trying to match the fact this function
// has already been parsed and that it would need to be re-lazified.
lazy->initRuntimeFields(packedFields);
}
}
// Code binding names.
if (!XDRLazyClosedOverBindings(xdr, lazy))
return false;
// No need to do anything with inner functions, since we asserted we don't
// have any.
return true;
}
static inline uint32_t
FindScopeIndex(JSScript* script, Scope& scope)
{
ScopeArray* scopes = script->scopes();
GCPtrScope* vector = scopes->vector;
unsigned length = scopes->length;
for (uint32_t i = 0; i < length; ++i) {
if (vector[i] == &scope)
return i;
}
MOZ_CRASH("Scope not found");
}
enum XDRClassKind {
CK_RegexpObject,
CK_JSFunction,
CK_JSObject
};
template<XDRMode mode>
bool
js::XDRScript(XDRState<mode>* xdr, HandleScope scriptEnclosingScope, HandleScript enclosingScript,
HandleFunction fun, MutableHandleScript scriptp)
{
/* NB: Keep this in sync with CopyScript. */
enum ScriptBits {
NoScriptRval,
Strict,
ContainsDynamicNameAccess,
FunHasExtensibleScope,
FunHasAnyAliasedFormal,
ArgumentsHasVarBinding,
NeedsArgsObj,
HasMappedArgsObj,
FunctionHasThisBinding,
FunctionHasExtraBodyVarScope,
IsGeneratorExp,
IsLegacyGenerator,
IsStarGenerator,
IsAsync,
HasRest,
OwnSource,
ExplicitUseStrict,
SelfHosted,
HasSingleton,
TreatAsRunOnce,
HasLazyScript,
HasNonSyntacticScope,
HasInnerFunctions,
NeedsHomeObject,
IsDerivedClassConstructor,
IsDefaultClassConstructor,
};
uint32_t length, lineno, column, nfixed, nslots;
uint32_t natoms, nsrcnotes, i;
uint32_t nconsts, nobjects, nscopes, nregexps, ntrynotes, nscopenotes, nyieldoffsets;
uint32_t prologueLength, version;
uint32_t funLength = 0;
uint32_t nTypeSets = 0;
uint32_t scriptBits = 0;
uint32_t bodyScopeIndex = 0;
JSContext* cx = xdr->cx();
RootedScript script(cx);
natoms = nsrcnotes = 0;
nconsts = nobjects = nscopes = nregexps = ntrynotes = nscopenotes = nyieldoffsets = 0;
if (mode == XDR_ENCODE) {
script = scriptp.get();
MOZ_ASSERT_IF(enclosingScript, enclosingScript->compartment() == script->compartment());
MOZ_ASSERT(script->functionNonDelazifying() == fun);
if (!fun && script->treatAsRunOnce()) {
// 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.
JSCompartment* comp = cx->compartment();
if (!comp->creationOptions().cloneSingletons() ||
!comp->behaviors().getSingletonsAsTemplates())
{
return xdr->fail(JS::TranscodeResult_Failure_RunOnceNotSupported);
}
}
}
if (mode == XDR_ENCODE)
length = script->length();
if (!xdr->codeUint32(&length))
return false;
if (mode == XDR_ENCODE) {
prologueLength = script->mainOffset();
MOZ_ASSERT(script->getVersion() != JSVERSION_UNKNOWN);
version = script->getVersion();
lineno = script->lineno();
column = script->column();
nfixed = script->nfixed();
nslots = script->nslots();
bodyScopeIndex = script->bodyScopeIndex();
natoms = script->natoms();
nsrcnotes = script->numNotes();
if (script->hasConsts())
nconsts = script->consts()->length;
if (script->hasObjects())
nobjects = script->objects()->length;
nscopes = script->scopes()->length;
if (script->hasTrynotes())
ntrynotes = script->trynotes()->length;
if (script->hasScopeNotes())
nscopenotes = script->scopeNotes()->length;
if (script->hasYieldOffsets())
nyieldoffsets = script->yieldOffsets().length();
nTypeSets = script->nTypeSets();
funLength = script->funLength();
if (script->noScriptRval())
scriptBits |= (1 << NoScriptRval);
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->funHasAnyAliasedFormal())
scriptBits |= (1 << FunHasAnyAliasedFormal);
if (script->argumentsHasVarBinding())
scriptBits |= (1 << ArgumentsHasVarBinding);
if (script->analyzedArgsUsage() && script->needsArgsObj())
scriptBits |= (1 << NeedsArgsObj);
if (script->hasMappedArgsObj())
scriptBits |= (1 << HasMappedArgsObj);
if (script->functionHasThisBinding())
scriptBits |= (1 << FunctionHasThisBinding);
if (script->functionHasExtraBodyVarScope())
scriptBits |= (1 << FunctionHasExtraBodyVarScope);
if (!enclosingScript || enclosingScript->scriptSource() != script->scriptSource())
scriptBits |= (1 << OwnSource);
if (script->isGeneratorExp())
scriptBits |= (1 << IsGeneratorExp);
if (script->isLegacyGenerator())
scriptBits |= (1 << IsLegacyGenerator);
if (script->isStarGenerator())
scriptBits |= (1 << IsStarGenerator);
if (script->asyncKind() == AsyncFunction)
scriptBits |= (1 << IsAsync);
if (script->hasRest())
scriptBits |= (1 << HasRest);
if (script->hasSingletons())
scriptBits |= (1 << HasSingleton);
if (script->treatAsRunOnce())
scriptBits |= (1 << TreatAsRunOnce);
if (script->isRelazifiable())
scriptBits |= (1 << HasLazyScript);
if (script->hasNonSyntacticScope())
scriptBits |= (1 << HasNonSyntacticScope);
if (script->hasInnerFunctions())
scriptBits |= (1 << HasInnerFunctions);
if (script->needsHomeObject())
scriptBits |= (1 << NeedsHomeObject);
if (script->isDerivedClassConstructor())
scriptBits |= (1 << IsDerivedClassConstructor);
if (script->isDefaultClassConstructor())
scriptBits |= (1 << IsDefaultClassConstructor);
}
if (!xdr->codeUint32(&prologueLength))
return false;
if (!xdr->codeUint32(&version))
return false;
// To fuse allocations, we need lengths of all embedded arrays early.
if (!xdr->codeUint32(&natoms))
return false;
if (!xdr->codeUint32(&nsrcnotes))
return false;
if (!xdr->codeUint32(&nconsts))
return false;
if (!xdr->codeUint32(&nobjects))
return false;
if (!xdr->codeUint32(&nscopes))
return false;
if (!xdr->codeUint32(&ntrynotes))
return false;
if (!xdr->codeUint32(&nscopenotes))
return false;
if (!xdr->codeUint32(&nyieldoffsets))
return false;
if (!xdr->codeUint32(&nTypeSets))
return false;
if (!xdr->codeUint32(&funLength))
return false;
if (!xdr->codeUint32(&scriptBits))
return false;
if (mode == XDR_DECODE) {
JSVersion version_ = JSVersion(version);
MOZ_ASSERT((version_ & VersionFlags::MASK) == unsigned(version_));
CompileOptions options(cx);
options.setVersion(version_)
.setNoScriptRval(!!(scriptBits & (1 << NoScriptRval)))
.setSelfHostingMode(!!(scriptBits & (1 << SelfHosted)));
RootedScriptSource sourceObject(cx);
if (scriptBits & (1 << OwnSource)) {
ScriptSource* ss = cx->new_<ScriptSource>();
if (!ss)
return false;
ScriptSourceHolder ssHolder(ss);
/*
* We use this CompileOptions only to initialize the
* ScriptSourceObject. Most CompileOptions fields aren't used by
* ScriptSourceObject, and those that are (element; elementAttributeName)
* aren't preserved by XDR. So this can be simple.
*/
CompileOptions options(cx);
ss->initFromOptions(cx, options);
sourceObject = ScriptSourceObject::create(cx, ss);
if (!sourceObject ||
!ScriptSourceObject::initFromOptions(cx, sourceObject, options))
return false;
} else {
MOZ_ASSERT(enclosingScript);
// When decoding, all the scripts and the script source object
// are in the same compartment, so the script's source object
// should never be a cross-compartment wrapper.
MOZ_ASSERT(enclosingScript->sourceObject()->is<ScriptSourceObject>());
sourceObject = &enclosingScript->sourceObject()->as<ScriptSourceObject>();
}
script = JSScript::Create(cx, options, sourceObject, 0, 0, 0);
if (!script)
return false;
// 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 (mode == XDR_DECODE) {
if (!JSScript::partiallyInit(cx, script, nscopes, nconsts, nobjects, ntrynotes,
nscopenotes, nyieldoffsets, nTypeSets))
{
return false;
}
MOZ_ASSERT(!script->mainOffset());
script->mainOffset_ = prologueLength;
script->funLength_ = funLength;
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 << FunHasAnyAliasedFormal))
script->funHasAnyAliasedFormal_ = true;
if (scriptBits & (1 << ArgumentsHasVarBinding))
script->setArgumentsHasVarBinding();
if (scriptBits & (1 << NeedsArgsObj))
script->setNeedsArgsObj(true);
if (scriptBits & (1 << HasMappedArgsObj))
script->hasMappedArgsObj_ = true;
if (scriptBits & (1 << FunctionHasThisBinding))
script->functionHasThisBinding_ = true;
if (scriptBits & (1 << FunctionHasExtraBodyVarScope))
script->functionHasExtraBodyVarScope_ = true;
if (scriptBits & (1 << IsGeneratorExp))
script->isGeneratorExp_ = true;
if (scriptBits & (1 << HasSingleton))
script->hasSingletons_ = true;
if (scriptBits & (1 << TreatAsRunOnce))
script->treatAsRunOnce_ = true;
if (scriptBits & (1 << HasNonSyntacticScope))
script->hasNonSyntacticScope_ = true;
if (scriptBits & (1 << HasInnerFunctions))
script->hasInnerFunctions_ = true;
if (scriptBits & (1 << NeedsHomeObject))
script->needsHomeObject_ = true;
if (scriptBits & (1 << IsDerivedClassConstructor))
script->isDerivedClassConstructor_ = true;
if (scriptBits & (1 << IsDefaultClassConstructor))
script->isDefaultClassConstructor_ = true;
if (scriptBits & (1 << IsLegacyGenerator)) {
MOZ_ASSERT(!(scriptBits & (1 << IsStarGenerator)));
script->setGeneratorKind(LegacyGenerator);
} else if (scriptBits & (1 << IsStarGenerator))
script->setGeneratorKind(StarGenerator);
if (scriptBits & (1 << IsAsync))
script->setAsyncKind(AsyncFunction);
if (scriptBits & (1 << HasRest))
script->setHasRest();
}
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(&script->preludeStart_))
return false;
if (!xdr->codeUint32(&lineno) ||
!xdr->codeUint32(&column) ||
!xdr->codeUint32(&nfixed) ||
!xdr->codeUint32(&nslots))
{
return false;
}
if (!xdr->codeUint32(&bodyScopeIndex))
return false;
if (mode == XDR_DECODE) {
script->lineno_ = lineno;
script->column_ = column;
script->nfixed_ = nfixed;
script->nslots_ = nslots;
script->bodyScopeIndex_ = bodyScopeIndex;
}
auto scriptDataGuard = mozilla::MakeScopeExit([&] {
if (mode == XDR_DECODE)
script->freeScriptData();
});
if (mode == XDR_DECODE) {
if (!script->createScriptData(cx, length, nsrcnotes, natoms))
return false;
}
jsbytecode* code = script->code();
if (!xdr->codeBytes(code, length) || !xdr->codeBytes(code + length, nsrcnotes)) {
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;
}
}
scriptDataGuard.release();
if (mode == XDR_DECODE) {
if (!script->shareScriptData(cx))
return false;
}
if (nconsts) {
GCPtrValue* vector = script->consts()->vector;
RootedValue val(cx);
for (i = 0; i != nconsts; ++i) {
if (mode == XDR_ENCODE)
val = vector[i];
if (!XDRScriptConst(xdr, &val))
return false;
if (mode == XDR_DECODE)
vector[i].init(val);
}
}
{
MOZ_ASSERT(nscopes != 0);
GCPtrScope* vector = script->scopes()->vector;
RootedScope scope(cx);
RootedScope enclosing(cx);
ScopeKind scopeKind;
uint32_t enclosingScopeIndex = 0;
for (i = 0; i != nscopes; ++i) {
if (mode == XDR_ENCODE) {
scope = vector[i];
scopeKind = scope->kind();
} else {
scope = nullptr;
}
if (!xdr->codeEnum32(&scopeKind))
return false;
if (mode == XDR_ENCODE) {
if (i == 0) {
enclosingScopeIndex = UINT32_MAX;
} else {
MOZ_ASSERT(scope->enclosing());
enclosingScopeIndex = FindScopeIndex(script, *scope->enclosing());
}
}
if (!xdr->codeUint32(&enclosingScopeIndex))
return false;
if (mode == XDR_DECODE) {
if (i == 0) {
MOZ_ASSERT(enclosingScopeIndex == UINT32_MAX);
enclosing = scriptEnclosingScope;
} else {
MOZ_ASSERT(enclosingScopeIndex < i);
enclosing = vector[enclosingScopeIndex];
}
}
switch (scopeKind) {
case ScopeKind::Function:
MOZ_ASSERT(i == script->bodyScopeIndex());
if (!FunctionScope::XDR(xdr, fun, enclosing, &scope))
return false;
break;
case ScopeKind::FunctionBodyVar:
case ScopeKind::ParameterExpressionVar:
if (!VarScope::XDR(xdr, scopeKind, enclosing, &scope))
return false;
break;
case ScopeKind::Lexical:
case ScopeKind::SimpleCatch:
case ScopeKind::Catch:
case ScopeKind::NamedLambda:
case ScopeKind::StrictNamedLambda:
if (!LexicalScope::XDR(xdr, scopeKind, enclosing, &scope))
return false;
break;
case ScopeKind::With:
if (mode == XDR_DECODE) {
scope = WithScope::create(cx, enclosing);
if (!scope)
return false;
}
break;
case ScopeKind::Eval:
case ScopeKind::StrictEval:
if (!EvalScope::XDR(xdr, scopeKind, enclosing, &scope))
return false;
break;
case ScopeKind::Global:
case ScopeKind::NonSyntactic:
if (!GlobalScope::XDR(xdr, scopeKind, &scope))
return false;
break;
case ScopeKind::Module:
MOZ_CRASH("NYI");
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);
}
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.
if (!xdr->codeMarker(0xF81F7F5A))
return false;
}
/*
* 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.
*/
for (i = 0; i != nobjects; ++i) {
GCPtrObject* objp = &script->objects()->vector[i];
XDRClassKind classk;
if (mode == XDR_ENCODE) {
JSObject* obj = *objp;
if (obj->is<RegExpObject>())
classk = CK_RegexpObject;
else if (obj->is<JSFunction>())
classk = CK_JSFunction;
else if (obj->is<PlainObject>() || obj->is<ArrayObject>())
classk = CK_JSObject;
else
MOZ_CRASH("Cannot encode this class of object.");
}
if (!xdr->codeEnum32(&classk))
return false;
switch (classk) {
case CK_RegexpObject: {
Rooted<RegExpObject*> regexp(cx);
if (mode == XDR_ENCODE)
regexp = &(*objp)->as<RegExpObject>();
if (!XDRScriptRegExpObject(xdr, &regexp))
return false;
if (mode == XDR_DECODE)
*objp = regexp;
break;
}
case CK_JSFunction: {
/* Code the nested function's enclosing scope. */
uint32_t funEnclosingScopeIndex = 0;
RootedScope funEnclosingScope(cx);
if (mode == XDR_ENCODE) {
RootedFunction function(cx, &(*objp)->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(script, *funEnclosingScope);
}
if (!xdr->codeUint32(&funEnclosingScopeIndex))
return false;
if (mode == XDR_DECODE) {
MOZ_ASSERT(funEnclosingScopeIndex < script->scopes()->length);
funEnclosingScope = script->scopes()->vector[funEnclosingScopeIndex];
}
// Code nested function and script.
RootedFunction tmp(cx);
if (mode == XDR_ENCODE)
tmp = &(*objp)->as<JSFunction>();
if (!XDRInterpretedFunction(xdr, funEnclosingScope, script, &tmp))
return false;
*objp = tmp;
break;
}
case CK_JSObject: {
/* Code object literal. */
RootedObject tmp(cx, *objp);
if (!XDRObjectLiteral(xdr, &tmp))
return false;
*objp = 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);
}
}
}
// Verify marker to detect data corruption after decoding object data. A
// mismatch here indicates we will almost certainly crash in release.
if (!xdr->codeMarker(0x223DB179))
return false;
if (ntrynotes != 0) {
JSTryNote* tnfirst = script->trynotes()->vector;
MOZ_ASSERT(script->trynotes()->length == ntrynotes);
JSTryNote* tn = tnfirst + ntrynotes;
do {
--tn;
if (!xdr->codeUint8(&tn->kind) ||
!xdr->codeUint32(&tn->stackDepth) ||
!xdr->codeUint32(&tn->start) ||
!xdr->codeUint32(&tn->length)) {
return false;
}
} while (tn != tnfirst);
}
for (i = 0; i < nscopenotes; ++i) {
ScopeNote* note = &script->scopeNotes()->vector[i];
if (!xdr->codeUint32(&note->index) ||
!xdr->codeUint32(&note->start) ||
!xdr->codeUint32(&note->length) ||
!xdr->codeUint32(&note->parent))
{
return false;
}
}
for (i = 0; i < nyieldoffsets; ++i) {
uint32_t* offset = &script->yieldOffsets()[i];
if (!xdr->codeUint32(offset))
return false;
}
if (scriptBits & (1 << HasLazyScript)) {
Rooted<LazyScript*> lazy(cx);
if (mode == XDR_ENCODE)
lazy = script->maybeLazyScript();
if (!XDRRelazificationInfo(xdr, fun, script, scriptEnclosingScope, &lazy))
return false;
if (mode == XDR_DECODE)
script->setLazyScript(lazy);
}
if (mode == XDR_DECODE) {
scriptp.set(script);
/* see BytecodeEmitter::tellDebuggerAboutCompiledScript */
if (!fun)
Debugger::onNewScript(cx, script);
}
return true;
}
template bool
js::XDRScript(XDRState<XDR_ENCODE>*, HandleScope, HandleScript, HandleFunction,
MutableHandleScript);
template bool
js::XDRScript(XDRState<XDR_DECODE>*, HandleScope, HandleScript, HandleFunction,
MutableHandleScript);
template<XDRMode mode>
bool
js::XDRLazyScript(XDRState<mode>* xdr, HandleScope enclosingScope, HandleScript enclosingScript,
HandleFunction fun, MutableHandle<LazyScript*> lazy)
{
JSContext* cx = xdr->cx();
{
uint32_t begin;
uint32_t end;
uint32_t preludeStart;
uint32_t lineno;
uint32_t column;
uint64_t packedFields;
if (mode == XDR_ENCODE) {
// Note: it's possible the LazyScript has a non-null script_ pointer
// to a JSScript. We don't encode it: we can just delazify the
// lazy script.
MOZ_ASSERT(fun == lazy->functionNonDelazifying());
begin = lazy->begin();
end = lazy->end();
preludeStart = lazy->preludeStart();
lineno = lazy->lineno();
column = lazy->column();
packedFields = lazy->packedFields();
}
if (!xdr->codeUint32(&begin) || !xdr->codeUint32(&end) ||
!xdr->codeUint32(&preludeStart) ||
!xdr->codeUint32(&lineno) || !xdr->codeUint32(&column) ||
!xdr->codeUint64(&packedFields))
{
return false;
}
if (mode == XDR_DECODE) {
lazy.set(LazyScript::Create(cx, fun, nullptr, enclosingScope, enclosingScript,
packedFields, begin, end, preludeStart, lineno, column));
if (!lazy)
return false;
fun->initLazyScript(lazy);
}
}
// Code closed-over bindings.
if (!XDRLazyClosedOverBindings(xdr, lazy))
return false;
// Code inner functions.
{
RootedFunction func(cx);
GCPtrFunction* innerFunctions = lazy->innerFunctions();
size_t numInnerFunctions = lazy->numInnerFunctions();
for (size_t i = 0; i < numInnerFunctions; i++) {
if (mode == XDR_ENCODE)
func = innerFunctions[i];
if (!XDRInterpretedFunction(xdr, nullptr, nullptr, &func))
return false;
if (mode == XDR_DECODE)
innerFunctions[i] = func;
}
}
return true;
}
template bool
js::XDRLazyScript(XDRState<XDR_ENCODE>*, HandleScope, HandleScript,
HandleFunction, MutableHandle<LazyScript*>);
template bool
js::XDRLazyScript(XDRState<XDR_DECODE>*, HandleScope, HandleScript,
HandleFunction, MutableHandle<LazyScript*>);
void
JSScript::setSourceObject(JSObject* object)
{
MOZ_ASSERT(compartment() == object->compartment());
sourceObject_ = object;
}
js::ScriptSourceObject&
JSScript::scriptSourceUnwrap() const {
return UncheckedUnwrap(sourceObject())->as<ScriptSourceObject>();
}
js::ScriptSource*
JSScript::scriptSource() const {
return scriptSourceUnwrap().source();
}
js::ScriptSource*
JSScript::maybeForwardedScriptSource() const {
return UncheckedUnwrap(MaybeForwarded(sourceObject()))->as<ScriptSourceObject>().source();
}
bool
JSScript::initScriptCounts(JSContext* cx)
{
MOZ_ASSERT(!hasScriptCounts());
// Record all pc which are the first instruction of a basic block.
mozilla::Vector<jsbytecode*, 16, SystemAllocPolicy> jumpTargets;
jsbytecode* mainPc = main();
jsbytecode* end = codeEnd();
for (jsbytecode* pc = code(); pc != end; pc = GetNextPc(pc)) {
if (BytecodeIsJumpTarget(JSOp(*pc)) || pc == mainPc) {
if (!jumpTargets.append(pc)) {
ReportOutOfMemory(cx);
return false;
}
}
}
// Initialize all PCCounts counters to 0.
ScriptCounts::PCCountsVector base;
if (!base.reserve(jumpTargets.length())) {
ReportOutOfMemory(cx);
return false;
}
for (size_t i = 0; i < jumpTargets.length(); i++)
base.infallibleEmplaceBack(pcToOffset(jumpTargets[i]));
// Create compartment's scriptCountsMap if necessary.
ScriptCountsMap* map = compartment()->scriptCountsMap;
if (!map) {
map = cx->new_<ScriptCountsMap>();
if (!map) {
ReportOutOfMemory(cx);
return false;
}
if (!map->init()) {
js_delete(map);
ReportOutOfMemory(cx);
return false;
}
compartment()->scriptCountsMap = map;
}
// Allocate the ScriptCounts.
ScriptCounts* sc = cx->new_<ScriptCounts>(Move(base));
if (!sc) {
ReportOutOfMemory(cx);
return false;
}
auto guardScriptCounts = mozilla::MakeScopeExit([&] () {
js_delete(sc);
});
// Register the current ScriptCounts in the compartment's map.
if (!map->putNew(this, sc)) {
ReportOutOfMemory(cx);
return false;
}
// safe to set this; we can't fail after this point.
hasScriptCounts_ = true;
guardScriptCounts.release();
// Enable interrupts in any interpreter frames running on this script. This
// is used to let the interpreter increment the PCCounts, if present.
for (ActivationIterator iter(cx->runtime()); !iter.done(); ++iter) {
if (iter->isInterpreter())
iter->asInterpreter()->enableInterruptsIfRunning(this);
}
return true;
}
static inline ScriptCountsMap::Ptr GetScriptCountsMapEntry(JSScript* script)
{
MOZ_ASSERT(script->hasScriptCounts());
ScriptCountsMap* map = script->compartment()->scriptCountsMap;
ScriptCountsMap::Ptr p = map->lookup(script);
MOZ_ASSERT(p);
return p;
}
ScriptCounts&
JSScript::getScriptCounts()
{
ScriptCountsMap::Ptr p = GetScriptCountsMapEntry(this);
return *p->value();
}
js::PCCounts*
ScriptCounts::maybeGetPCCounts(size_t offset) {
PCCounts searched = PCCounts(offset);
PCCounts* elem = std::lower_bound(pcCounts_.begin(), pcCounts_.end(), searched);
if (elem == pcCounts_.end() || elem->pcOffset() != offset)
return nullptr;
return elem;
}
const js::PCCounts*
ScriptCounts::maybeGetPCCounts(size_t offset) const {
PCCounts searched = PCCounts(offset);
const PCCounts* elem = std::lower_bound(pcCounts_.begin(), pcCounts_.end(), searched);
if (elem == pcCounts_.end() || elem->pcOffset() != offset)
return nullptr;
return elem;
}
js::PCCounts*
ScriptCounts::getImmediatePrecedingPCCounts(size_t offset)
{
PCCounts searched = PCCounts(offset);
PCCounts* elem = std::lower_bound(pcCounts_.begin(), pcCounts_.end(), searched);
if (elem == pcCounts_.end())
return &pcCounts_.back();
if (elem->pcOffset() == offset)
return elem;
if (elem != pcCounts_.begin())
return elem - 1;
return nullptr;
}
const js::PCCounts*
ScriptCounts::maybeGetThrowCounts(size_t offset) const {
PCCounts searched = PCCounts(offset);
const PCCounts* elem = std::lower_bound(throwCounts_.begin(), throwCounts_.end(), searched);
if (elem == throwCounts_.end() || elem->pcOffset() != offset)
return nullptr;
return elem;
}
const js::PCCounts*
ScriptCounts::getImmediatePrecedingThrowCounts(size_t offset) const
{
PCCounts searched = PCCounts(offset);
const PCCounts* elem = std::lower_bound(throwCounts_.begin(), throwCounts_.end(), searched);
if (elem == throwCounts_.end()) {
if (throwCounts_.begin() == throwCounts_.end())
return nullptr;
return &throwCounts_.back();
}
if (elem->pcOffset() == offset)
return elem;
if (elem != throwCounts_.begin())
return elem - 1;
return nullptr;
}
js::PCCounts*
ScriptCounts::getThrowCounts(size_t offset) {
PCCounts searched = PCCounts(offset);
PCCounts* elem = std::lower_bound(throwCounts_.begin(), throwCounts_.end(), searched);
if (elem == throwCounts_.end() || elem->pcOffset() != offset)
elem = throwCounts_.insert(elem, searched);
return elem;
}
void
JSScript::setIonScript(JSRuntime* maybeRuntime, js::jit::IonScript* ionScript)
{
MOZ_ASSERT_IF(ionScript != ION_DISABLED_SCRIPT, !baselineScript()->hasPendingIonBuilder());
if (hasIonScript())
js::jit::IonScript::writeBarrierPre(zone(), ion);
ion = ionScript;
MOZ_ASSERT_IF(hasIonScript(), hasBaselineScript());
updateBaselineOrIonRaw(maybeRuntime);
}
js::PCCounts*
JSScript::maybeGetPCCounts(jsbytecode* pc) {
MOZ_ASSERT(containsPC(pc));
return getScriptCounts().maybeGetPCCounts(pcToOffset(pc));
}
const js::PCCounts*
JSScript::maybeGetThrowCounts(jsbytecode* pc) {
MOZ_ASSERT(containsPC(pc));
return getScriptCounts().maybeGetThrowCounts(pcToOffset(pc));
}
js::PCCounts*
JSScript::getThrowCounts(jsbytecode* pc) {
MOZ_ASSERT(containsPC(pc));
return getScriptCounts().getThrowCounts(pcToOffset(pc));
}
uint64_t
JSScript::getHitCount(jsbytecode* pc)
{
MOZ_ASSERT(containsPC(pc));
if (pc < main())
pc = main();
ScriptCounts& sc = getScriptCounts();
size_t targetOffset = pcToOffset(pc);
const js::PCCounts* baseCount = sc.getImmediatePrecedingPCCounts(targetOffset);
if (!baseCount)
return 0;
if (baseCount->pcOffset() == targetOffset)
return baseCount->numExec();
MOZ_ASSERT(baseCount->pcOffset() < targetOffset);
uint64_t count = baseCount->numExec();
do {
const js::PCCounts* throwCount = sc.getImmediatePrecedingThrowCounts(targetOffset);
if (!throwCount)
return count;
if (throwCount->pcOffset() <= baseCount->pcOffset())
return count;
count -= throwCount->numExec();
targetOffset = throwCount->pcOffset() - 1;
} while (true);
}
void
JSScript::incHitCount(jsbytecode* pc)
{
MOZ_ASSERT(containsPC(pc));
if (pc < main())
pc = main();
ScriptCounts& sc = getScriptCounts();
js::PCCounts* baseCount = sc.getImmediatePrecedingPCCounts(pcToOffset(pc));
if (!baseCount)
return;
baseCount->numExec()++;
}
void
JSScript::addIonCounts(jit::IonScriptCounts* ionCounts)
{
ScriptCounts& sc = getScriptCounts();
if (sc.ionCounts_)
ionCounts->setPrevious(sc.ionCounts_);
sc.ionCounts_ = ionCounts;
}
jit::IonScriptCounts*
JSScript::getIonCounts()
{
return getScriptCounts().ionCounts_;
}
void
JSScript::takeOverScriptCountsMapEntry(ScriptCounts* entryValue)
{
#ifdef DEBUG
ScriptCountsMap::Ptr p = GetScriptCountsMapEntry(this);
MOZ_ASSERT(entryValue == p->value());
#endif
hasScriptCounts_ = false;
}
void
JSScript::releaseScriptCounts(ScriptCounts* counts)
{
ScriptCountsMap::Ptr p = GetScriptCountsMapEntry(this);
*counts = Move(*p->value());
js_delete(p->value());
compartment()->scriptCountsMap->remove(p);
hasScriptCounts_ = false;
}
void
JSScript::destroyScriptCounts(FreeOp* fop)
{
if (hasScriptCounts()) {
ScriptCounts scriptCounts;
releaseScriptCounts(&scriptCounts);
}
}
void
ScriptSourceObject::trace(JSTracer* trc, JSObject* obj)
{
ScriptSourceObject* sso = static_cast<ScriptSourceObject*>(obj);
// Don't trip over the poison 'not yet initialized' values.
if (!sso->getReservedSlot(INTRODUCTION_SCRIPT_SLOT).isMagic(JS_GENERIC_MAGIC)) {
JSScript* script = sso->introductionScript();
if (script) {
TraceManuallyBarrieredEdge(trc, &script, "ScriptSourceObject introductionScript");
sso->setReservedSlot(INTRODUCTION_SCRIPT_SLOT, PrivateValue(script));
}
}
}
void
ScriptSourceObject::finalize(FreeOp* fop, JSObject* obj)
{
MOZ_ASSERT(fop->onMainThread());
ScriptSourceObject* sso = &obj->as<ScriptSourceObject>();
// If code coverage is enabled, record the filename associated with this
// source object.
if (fop->runtime()->lcovOutput.isEnabled())
sso->compartment()->lcovOutput.collectSourceFile(sso->compartment(), sso);
sso->source()->decref();
sso->setReservedSlot(SOURCE_SLOT, PrivateValue(nullptr));
}
static const ClassOps ScriptSourceObjectClassOps = {
nullptr, /* addProperty */
nullptr, /* delProperty */
nullptr, /* getProperty */
nullptr, /* setProperty */
nullptr, /* enumerate */
nullptr, /* resolve */
nullptr, /* mayResolve */
ScriptSourceObject::finalize,
nullptr, /* call */
nullptr, /* hasInstance */
nullptr, /* construct */
ScriptSourceObject::trace
};
const Class ScriptSourceObject::class_ = {
"ScriptSource",
JSCLASS_HAS_RESERVED_SLOTS(RESERVED_SLOTS) |
JSCLASS_IS_ANONYMOUS |
JSCLASS_FOREGROUND_FINALIZE,
&ScriptSourceObjectClassOps
};
ScriptSourceObject*
ScriptSourceObject::create(ExclusiveContext* cx, ScriptSource* source)
{
RootedObject object(cx, NewObjectWithGivenProto(cx, &class_, nullptr));
if (!object)
return nullptr;
RootedScriptSource sourceObject(cx, &object->as<ScriptSourceObject>());
source->incref(); // The matching decref is in ScriptSourceObject::finalize.
sourceObject->initReservedSlot(SOURCE_SLOT, PrivateValue(source));
// The remaining slots should eventually be populated by a call to
// initFromOptions. Poison them until that point.
sourceObject->initReservedSlot(ELEMENT_SLOT, MagicValue(JS_GENERIC_MAGIC));
sourceObject->initReservedSlot(ELEMENT_PROPERTY_SLOT, MagicValue(JS_GENERIC_MAGIC));
sourceObject->initReservedSlot(INTRODUCTION_SCRIPT_SLOT, MagicValue(JS_GENERIC_MAGIC));
return sourceObject;
}
/* static */ bool
ScriptSourceObject::initFromOptions(JSContext* cx, HandleScriptSource source,
const ReadOnlyCompileOptions& options)
{
releaseAssertSameCompartment(cx, source);
MOZ_ASSERT(source->getReservedSlot(ELEMENT_SLOT).isMagic(JS_GENERIC_MAGIC));
MOZ_ASSERT(source->getReservedSlot(ELEMENT_PROPERTY_SLOT).isMagic(JS_GENERIC_MAGIC));
MOZ_ASSERT(source->getReservedSlot(INTRODUCTION_SCRIPT_SLOT).isMagic(JS_GENERIC_MAGIC));
RootedValue element(cx, ObjectOrNullValue(options.element()));
if (!cx->compartment()->wrap(cx, &element))
return false;
source->setReservedSlot(ELEMENT_SLOT, element);
RootedValue elementAttributeName(cx);
if (options.elementAttributeName())
elementAttributeName = StringValue(options.elementAttributeName());
else
elementAttributeName = UndefinedValue();
if (!cx->compartment()->wrap(cx, &elementAttributeName))
return false;
source->setReservedSlot(ELEMENT_PROPERTY_SLOT, elementAttributeName);
// There is no equivalent of cross-compartment wrappers for scripts. If the
// introduction script and ScriptSourceObject are in different compartments,
// we would be creating a cross-compartment script reference, which is
// forbidden. In that case, simply don't bother to retain the introduction
// script.
if (options.introductionScript() &&
options.introductionScript()->compartment() == cx->compartment())
{
source->setReservedSlot(INTRODUCTION_SCRIPT_SLOT, PrivateValue(options.introductionScript()));
} else {
source->setReservedSlot(INTRODUCTION_SCRIPT_SLOT, UndefinedValue());
}
return true;
}
/* static */ bool
JSScript::loadSource(JSContext* cx, ScriptSource* ss, bool* worked)
{
MOZ_ASSERT(!ss->hasSourceData());
*worked = false;
if (!cx->runtime()->sourceHook || !ss->sourceRetrievable())
return true;
char16_t* src = nullptr;
size_t length;
if (!cx->runtime()->sourceHook->load(cx, ss->filename(), &src, &length))
return false;
if (!src)
return true;
if (!ss->setSource(cx, mozilla::UniquePtr<char16_t[], JS::FreePolicy>(src), length))
return false;
*worked = true;
return true;
}
JSFlatString*
JSScript::sourceData(JSContext* cx)
{
MOZ_ASSERT(scriptSource()->hasSourceData());
return scriptSource()->substring(cx, sourceStart(), sourceEnd());
}
JSFlatString*
JSScript::sourceDataWithPrelude(JSContext* cx)
{
MOZ_ASSERT(scriptSource()->hasSourceData());
return scriptSource()->substring(cx, preludeStart(), sourceEnd());
}
UncompressedSourceCache::AutoHoldEntry::AutoHoldEntry()
: cache_(nullptr), sourceChunk_()
{
}
void
UncompressedSourceCache::AutoHoldEntry::holdEntry(UncompressedSourceCache* cache,
const ScriptSourceChunk& sourceChunk)
{
// Initialise the holder for a specific cache and script source. This will
// hold on to the cached source chars in the event that the cache is purged.
MOZ_ASSERT(!cache_ && !sourceChunk_.valid() && !charsToFree_);
cache_ = cache;
sourceChunk_ = sourceChunk;
}
void
UncompressedSourceCache::AutoHoldEntry::holdChars(UniqueTwoByteChars chars)
{
MOZ_ASSERT(!cache_ && !sourceChunk_.valid() && !charsToFree_);
charsToFree_ = Move(chars);
}
void
UncompressedSourceCache::AutoHoldEntry::deferDelete(UniqueTwoByteChars chars)
{
// Take ownership of source chars now the cache is being purged. Remove our
// reference to the ScriptSource which might soon be destroyed.
MOZ_ASSERT(cache_ && sourceChunk_.valid() && !charsToFree_);
cache_ = nullptr;
sourceChunk_ = ScriptSourceChunk();
charsToFree_ = Move(chars);
}
UncompressedSourceCache::AutoHoldEntry::~AutoHoldEntry()
{
if (cache_) {
MOZ_ASSERT(sourceChunk_.valid());
cache_->releaseEntry(*this);
}
}
void
UncompressedSourceCache::holdEntry(AutoHoldEntry& holder, const ScriptSourceChunk& ssc)
{
MOZ_ASSERT(!holder_);
holder.holdEntry(this, ssc);
holder_ = &holder;
}
void
UncompressedSourceCache::releaseEntry(AutoHoldEntry& holder)
{
MOZ_ASSERT(holder_ == &holder);
holder_ = nullptr;
}
const char16_t*
UncompressedSourceCache::lookup(const ScriptSourceChunk& ssc, AutoHoldEntry& holder)
{
MOZ_ASSERT(!holder_);
if (!map_)
return nullptr;
if (Map::Ptr p = map_->lookup(ssc)) {
holdEntry(holder, ssc);
return p->value().get();
}
return nullptr;
}
bool
UncompressedSourceCache::put(const ScriptSourceChunk& ssc, UniqueTwoByteChars str,
AutoHoldEntry& holder)
{
MOZ_ASSERT(!holder_);
if (!map_) {
UniquePtr<Map> map = MakeUnique<Map>();
if (!map || !map->init())
return false;
map_ = Move(map);
}
if (!map_->put(ssc, Move(str)))
return false;
holdEntry(holder, ssc);
return true;
}
void
UncompressedSourceCache::purge()
{
if (!map_)
return;
for (Map::Range r = map_->all(); !r.empty(); r.popFront()) {
if (holder_ && r.front().key() == holder_->sourceChunk()) {
holder_->deferDelete(Move(r.front().value()));
holder_ = nullptr;
}
}
map_.reset();
}
size_t
UncompressedSourceCache::sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf)
{
size_t n = 0;
if (map_ && !map_->empty()) {
n += map_->sizeOfIncludingThis(mallocSizeOf);
for (Map::Range r = map_->all(); !r.empty(); r.popFront())
n += mallocSizeOf(r.front().value().get());
}
return n;
}
const char16_t*
ScriptSource::chunkChars(JSContext* cx, UncompressedSourceCache::AutoHoldEntry& holder,
size_t chunk)
{
const Compressed& c = data.as<Compressed>();
ScriptSourceChunk ssc(this, chunk);
if (const char16_t* decompressed = cx->caches.uncompressedSourceCache.lookup(ssc, holder))
return decompressed;
size_t totalLengthInBytes = length() * sizeof(char16_t);
size_t chunkBytes = Compressor::chunkSize(totalLengthInBytes, chunk);
MOZ_ASSERT((chunkBytes % sizeof(char16_t)) == 0);
const size_t lengthWithNull = (chunkBytes / sizeof(char16_t)) + 1;
UniqueTwoByteChars decompressed(js_pod_malloc<char16_t>(lengthWithNull));
if (!decompressed) {
JS_ReportOutOfMemory(cx);
return nullptr;
}
if (!DecompressStringChunk((const unsigned char*) c.raw.chars(),
chunk,
reinterpret_cast<unsigned char*>(decompressed.get()),
chunkBytes))
{
JS_ReportOutOfMemory(cx);
return nullptr;
}
decompressed[lengthWithNull - 1] = '\0';
const char16_t* ret = decompressed.get();
if (!cx->caches.uncompressedSourceCache.put(ssc, Move(decompressed), holder)) {
JS_ReportOutOfMemory(cx);
return nullptr;
}
return ret;
}
const char16_t*
ScriptSource::chars(JSContext* cx, UncompressedSourceCache::AutoHoldEntry& holder,
size_t begin, size_t len)
{
MOZ_ASSERT(begin + len <= length());
if (data.is<Uncompressed>()) {
const char16_t* chars = data.as<Uncompressed>().string.chars();
if (!chars)
return nullptr;
return chars + begin;
}
if (data.is<Missing>())
MOZ_CRASH("ScriptSource::chars() on ScriptSource with SourceType = Missing");
MOZ_ASSERT(data.is<Compressed>());
// Determine which chunk(s) we are interested in, and the offsets within
// these chunks.
size_t firstChunk, lastChunk;
size_t firstChunkOffset, lastChunkOffset;
MOZ_ASSERT(len > 0);
Compressor::toChunkOffset(begin * sizeof(char16_t), &firstChunk, &firstChunkOffset);
Compressor::toChunkOffset((begin + len - 1) * sizeof(char16_t), &lastChunk, &lastChunkOffset);
MOZ_ASSERT(firstChunkOffset % sizeof(char16_t) == 0);
size_t firstChar = firstChunkOffset / sizeof(char16_t);
if (firstChunk == lastChunk) {
const char16_t* chars = chunkChars(cx, holder, firstChunk);
if (!chars)
return nullptr;
return chars + firstChar;
}
// We need multiple chunks. Allocate a (null-terminated) buffer to hold
// |len| chars and copy uncompressed chars from the chunks into it. We use
// chunkChars() so we benefit from chunk caching by UncompressedSourceCache.
MOZ_ASSERT(firstChunk < lastChunk);
size_t lengthWithNull = len + 1;
UniqueTwoByteChars decompressed(js_pod_malloc<char16_t>(lengthWithNull));
if (!decompressed) {
JS_ReportOutOfMemory(cx);
return nullptr;
}
size_t totalLengthInBytes = length() * sizeof(char16_t);
char16_t* cursor = decompressed.get();
for (size_t i = firstChunk; i <= lastChunk; i++) {
UncompressedSourceCache::AutoHoldEntry chunkHolder;
const char16_t* chars = chunkChars(cx, chunkHolder, i);
if (!chars)
return nullptr;
size_t numChars = Compressor::chunkSize(totalLengthInBytes, i) / sizeof(char16_t);
if (i == firstChunk) {
MOZ_ASSERT(firstChar < numChars);
chars += firstChar;
numChars -= firstChar;
} else if (i == lastChunk) {
size_t numCharsNew = lastChunkOffset / sizeof(char16_t) + 1;
MOZ_ASSERT(numCharsNew <= numChars);
numChars = numCharsNew;
}
mozilla::PodCopy(cursor, chars, numChars);
cursor += numChars;
}
*cursor++ = '\0';
MOZ_ASSERT(size_t(cursor - decompressed.get()) == lengthWithNull);
// Transfer ownership to |holder|.
const char16_t* ret = decompressed.get();
holder.holdChars(Move(decompressed));
return ret;
}
JSFlatString*
ScriptSource::substring(JSContext* cx, size_t start, size_t stop)
{
MOZ_ASSERT(start <= stop);
size_t len = stop - start;
UncompressedSourceCache::AutoHoldEntry holder;
const char16_t* chars = this->chars(cx, holder, start, len);
if (!chars)
return nullptr;
return NewStringCopyN<CanGC>(cx, chars, len);
}
JSFlatString*
ScriptSource::substringDontDeflate(JSContext* cx, size_t start, size_t stop)
{
MOZ_ASSERT(start <= stop);
size_t len = stop - start;
UncompressedSourceCache::AutoHoldEntry holder;
const char16_t* chars = this->chars(cx, holder, start, len);
if (!chars)
return nullptr;
return NewStringCopyNDontDeflate<CanGC>(cx, chars, len);
}
JSFlatString*
ScriptSource::functionBodyString(JSContext* cx)
{
MOZ_ASSERT(isFunctionBody());
size_t start = parameterListEnd_ + (sizeof(FunctionConstructorMedialSigils) - 1);
size_t stop = length() - (sizeof(FunctionConstructorFinalBrace) - 1);
return substring(cx, start, stop);
}
MOZ_MUST_USE bool
ScriptSource::setSource(ExclusiveContext* cx,
mozilla::UniquePtr<char16_t[], JS::FreePolicy>&& source,
size_t length)
{
auto& cache = cx->zone()->runtimeFromAnyThread()->sharedImmutableStrings();
auto deduped = cache.getOrCreate(mozilla::Move(source), length);
if (!deduped) {
ReportOutOfMemory(cx);
return false;
}
setSource(mozilla::Move(*deduped));
return true;
}
void
ScriptSource::setSource(SharedImmutableTwoByteString&& string)
{
MOZ_ASSERT(data.is<Missing>());
data = SourceType(Uncompressed(mozilla::Move(string)));
}
MOZ_MUST_USE bool
ScriptSource::setCompressedSource(ExclusiveContext* cx,
mozilla::UniquePtr<char[], JS::FreePolicy>&& raw,
size_t rawLength,
size_t sourceLength)
{
MOZ_ASSERT(raw);
auto& cache = cx->zone()->runtimeFromAnyThread()->sharedImmutableStrings();
auto deduped = cache.getOrCreate(mozilla::Move(raw), rawLength);
if (!deduped) {
ReportOutOfMemory(cx);
return false;
}
setCompressedSource(mozilla::Move(*deduped), sourceLength);
return true;
}
void
ScriptSource::setCompressedSource(SharedImmutableString&& raw, size_t uncompressedLength)
{
MOZ_ASSERT(data.is<Missing>() || data.is<Uncompressed>());
MOZ_ASSERT_IF(data.is<Uncompressed>(),
data.as<Uncompressed>().string.length() == uncompressedLength);
data = SourceType(Compressed(mozilla::Move(raw), uncompressedLength));
}
bool
ScriptSource::setSourceCopy(ExclusiveContext* cx, SourceBufferHolder& srcBuf,
SourceCompressionTask* task)
{
MOZ_ASSERT(!hasSourceData());
auto& cache = cx->zone()->runtimeFromAnyThread()->sharedImmutableStrings();
auto deduped = cache.getOrCreate(srcBuf.get(), srcBuf.length(), [&]() {
return srcBuf.ownsChars()
? mozilla::UniquePtr<char16_t[], JS::FreePolicy>(srcBuf.take())
: DuplicateString(srcBuf.get(), srcBuf.length());
});
if (!deduped) {
ReportOutOfMemory(cx);
return false;
}
setSource(mozilla::Move(*deduped));
// There are several cases where source compression is not a good idea:
// - If the script is tiny, then compression will save little or no space.
// - If there is only one core, then compression will contend with JS
// execution (which hurts benchmarketing).
// - If the source contains a giant string, then parsing will finish much
// faster than compression which increases latency (this case is handled
// in Parser::stringLiteral).
//
// Lastly, since the parsing thread will eventually perform a blocking wait
// on the compression task's thread, require that there are at least 2
// helper threads:
// - If we are on a helper thread, there must be another helper thread to
// execute our compression task.
// - If we are on the main thread, there must be at least two helper
// threads since at most one helper thread can be blocking on the main
// thread (see HelperThreadState::canStartParseTask) which would cause a
// deadlock if there wasn't a second helper thread that could make
// progress on our compression task.
bool canCompressOffThread =
HelperThreadState().cpuCount > 1 &&
HelperThreadState().threadCount >= 2 &&
CanUseExtraThreads();
const size_t TINY_SCRIPT = 256;
if (TINY_SCRIPT <= srcBuf.length() && canCompressOffThread) {
task->ss = this;
if (!StartOffThreadCompression(cx, task))
return false;
}
return true;
}
static MOZ_MUST_USE bool
reallocUniquePtr(UniquePtr<char[], JS::FreePolicy>& unique, size_t size)
{
auto newPtr = static_cast<char*>(js_realloc(unique.get(), size));
if (!newPtr)
return false;
// Since the realloc succeeded, unique is now holding a freed pointer.
mozilla::Unused << unique.release();
unique.reset(newPtr);
return true;
}
SourceCompressionTask::ResultType
SourceCompressionTask::work()
{
MOZ_ASSERT(ss->data.is<ScriptSource::Uncompressed>());
// Try to keep the maximum memory usage down by only allocating half the
// size of the string, first.
size_t inputBytes = ss->length() * sizeof(char16_t);
size_t firstSize = inputBytes / 2;
mozilla::UniquePtr<char[], JS::FreePolicy> compressed(js_pod_malloc<char>(firstSize));
if (!compressed)
return OOM;
const char16_t* chars = ss->data.as<ScriptSource::Uncompressed>().string.chars();
Compressor comp(reinterpret_cast<const unsigned char*>(chars),
inputBytes);
if (!comp.init())
return OOM;
comp.setOutput(reinterpret_cast<unsigned char*>(compressed.get()), firstSize);
bool cont = true;
bool reallocated = false;
while (cont) {
if (abort_)
return Aborted;
switch (comp.compressMore()) {
case Compressor::CONTINUE:
break;
case Compressor::MOREOUTPUT: {
if (reallocated) {
// The compressed string is longer than the original string.
return Aborted;
}
// The compressed output is greater than half the size of the
// original string. Reallocate to the full size.
if (!reallocUniquePtr(compressed, inputBytes))
return OOM;
comp.setOutput(reinterpret_cast<unsigned char*>(compressed.get()), inputBytes);
reallocated = true;
break;
}
case Compressor::DONE:
cont = false;
break;
case Compressor::OOM:
return OOM;
}
}
size_t totalBytes = comp.totalBytesNeeded();
// Shrink the buffer to the size of the compressed data.
if (!reallocUniquePtr(compressed, totalBytes))
return OOM;
comp.finish(compressed.get(), totalBytes);
auto& strings = cx->sharedImmutableStrings();
resultString = strings.getOrCreate(mozilla::Move(compressed), totalBytes);
if (!resultString)
return OOM;
return Success;
}
void
ScriptSource::addSizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf,
JS::ScriptSourceInfo* info) const
{
info->misc += mallocSizeOf(this) +
mallocSizeOf(filename_.get()) +
mallocSizeOf(introducerFilename_.get());
info->numScripts++;
}
template<XDRMode mode>
bool
ScriptSource::performXDR(XDRState<mode>* xdr)
{
struct CompressedLengthMatcher
{
size_t match(Uncompressed&) {
return 0;
}
size_t match(Compressed& c) {
return c.raw.length();
}
size_t match(Missing&) {
MOZ_CRASH("Missing source data in ScriptSource::performXDR");
return 0;
}
};
struct RawDataMatcher
{
void* match(Uncompressed& u) {
return (void*) u.string.chars();
}
void* match(Compressed& c) {
return (void*) c.raw.chars();
}
void* match(Missing&) {
MOZ_CRASH("Missing source data in ScriptSource::performXDR");
return nullptr;
}
};
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_) {
uint32_t len = 0;
if (mode == XDR_ENCODE)
len = length();
if (!xdr->codeUint32(&len))
return false;
uint32_t compressedLength;
if (mode == XDR_ENCODE) {
CompressedLengthMatcher m;
compressedLength = data.match(m);
}
if (!xdr->codeUint32(&compressedLength))
return false;
size_t byteLen = compressedLength ? compressedLength : (len * sizeof(char16_t));
if (mode == XDR_DECODE) {
uint8_t* p = xdr->cx()->template pod_malloc<uint8_t>(Max<size_t>(byteLen, 1));
if (!p || !xdr->codeBytes(p, byteLen)) {
js_free(p);
return false;
}
if (compressedLength) {
mozilla::UniquePtr<char[], JS::FreePolicy> compressedSource(
reinterpret_cast<char*>(p));
if (!setCompressedSource(xdr->cx(), mozilla::Move(compressedSource), byteLen, len))
return false;
} else {
mozilla::UniquePtr<char16_t[], JS::FreePolicy> source(
reinterpret_cast<char16_t*>(p));
if (!setSource(xdr->cx(), mozilla::Move(source), len))
return false;
}
} else {
RawDataMatcher rdm;
void* p = data.match(rdm);
if (!xdr->codeBytes(p, byteLen))
return false;
}
}
uint8_t haveSourceMap = hasSourceMapURL();
if (!xdr->codeUint8(&haveSourceMap))
return false;
if (haveSourceMap) {
uint32_t sourceMapURLLen = (mode == XDR_DECODE) ? 0 : js_strlen(sourceMapURL_.get());
if (!xdr->codeUint32(&sourceMapURLLen))
return false;
if (mode == XDR_DECODE) {
sourceMapURL_ = xdr->cx()->template make_pod_array<char16_t>(sourceMapURLLen + 1);
if (!sourceMapURL_)
return false;
}
if (!xdr->codeChars(sourceMapURL_.get(), sourceMapURLLen)) {
if (mode == XDR_DECODE)
sourceMapURL_ = nullptr;
return false;
}
sourceMapURL_[sourceMapURLLen] = '\0';
}
uint8_t haveDisplayURL = hasDisplayURL();
if (!xdr->codeUint8(&haveDisplayURL))
return false;
if (haveDisplayURL) {
uint32_t displayURLLen = (mode == XDR_DECODE) ? 0 : js_strlen(displayURL_.get());
if (!xdr->codeUint32(&displayURLLen))
return false;
if (mode == XDR_DECODE) {
displayURL_ = xdr->cx()->template make_pod_array<char16_t>(displayURLLen + 1);
if (!displayURL_)
return false;
}
if (!xdr->codeChars(displayURL_.get(), displayURLLen)) {
if (mode == XDR_DECODE)
displayURL_ = nullptr;
return false;
}
displayURL_[displayURLLen] = '\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;
}
return true;
}
// Format and return a cx->zone()->pod_malloc'ed URL for a generated script like:
// {filename} line {lineno} > {introducer}
// For example:
// foo.js line 7 > eval
// indicating code compiled by the call to 'eval' on line 7 of foo.js.
static char*
FormatIntroducedFilename(ExclusiveContext* cx, const char* filename, unsigned lineno,
const char* introducer)
{
// Compute the length of the string in advance, so we can allocate a
// buffer of the right size on the first shot.
//
// (JS_smprintf would be perfect, as that allocates the result
// dynamically as it formats the string, but it won't allocate from cx,
// and wants us to use a special free function.)
char linenoBuf[15];
size_t filenameLen = strlen(filename);
size_t linenoLen = SprintfLiteral(linenoBuf, "%u", lineno);
size_t introducerLen = strlen(introducer);
size_t len = filenameLen +
6 /* == strlen(" line ") */ +
linenoLen +
3 /* == strlen(" > ") */ +
introducerLen +
1 /* \0 */;
char* formatted = cx->zone()->pod_malloc<char>(len);
if (!formatted) {
ReportOutOfMemory(cx);
return nullptr;
}
mozilla::DebugOnly<size_t> checkLen = snprintf(formatted, len, "%s line %s > %s",
filename, linenoBuf, introducer);
MOZ_ASSERT(checkLen == len - 1);
return formatted;
}
bool
ScriptSource::initFromOptions(ExclusiveContext* cx, const ReadOnlyCompileOptions& options,
Maybe<uint32_t> parameterListEnd)
{
MOZ_ASSERT(!filename_);
MOZ_ASSERT(!introducerFilename_);
mutedErrors_ = options.mutedErrors();
introductionType_ = options.introductionType;
setIntroductionOffset(options.introductionOffset);
parameterListEnd_ = parameterListEnd.isSome() ? parameterListEnd.value() : 0;
if (options.hasIntroductionInfo) {
MOZ_ASSERT(options.introductionType != nullptr);
const char* filename = options.filename() ? options.filename() : "<unknown>";
char* formatted = FormatIntroducedFilename(cx, filename, options.introductionLineno,
options.introductionType);
if (!formatted)
return false;
filename_.reset(formatted);
} else if (options.filename()) {
if (!setFilename(cx, options.filename()))
return false;
}
if (options.introducerFilename()) {
introducerFilename_ = DuplicateString(cx, options.introducerFilename());
if (!introducerFilename_)
return false;
}
return true;
}
bool
ScriptSource::setFilename(ExclusiveContext* cx, const char* filename)
{
MOZ_ASSERT(!filename_);
filename_ = DuplicateString(cx, filename);
return filename_ != nullptr;
}
bool
ScriptSource::setDisplayURL(ExclusiveContext* cx, const char16_t* displayURL)
{
MOZ_ASSERT(displayURL);
if (hasDisplayURL()) {
// FIXME: filename_.get() should be UTF-8 (bug 987069).
if (cx->isJSContext() &&
!JS_ReportErrorFlagsAndNumberLatin1(cx->asJSContext(), JSREPORT_WARNING,
GetErrorMessage, nullptr,
JSMSG_ALREADY_HAS_PRAGMA, filename_.get(),
"//# sourceURL"))
{
return false;
}
}
size_t len = js_strlen(displayURL) + 1;
if (len == 1)
return true;
displayURL_ = DuplicateString(cx, displayURL);
return displayURL_ != nullptr;
}
bool
ScriptSource::setSourceMapURL(ExclusiveContext* cx, const char16_t* sourceMapURL)
{
MOZ_ASSERT(sourceMapURL);
size_t len = js_strlen(sourceMapURL) + 1;
if (len == 1)
return true;
sourceMapURL_ = DuplicateString(cx, sourceMapURL);
return sourceMapURL_ != nullptr;
}
/*
* Shared script data management.
*/
SharedScriptData*
js::SharedScriptData::new_(ExclusiveContext* cx, uint32_t codeLength,
uint32_t srcnotesLength, uint32_t natoms)
{
uint32_t dataLength = natoms * sizeof(GCPtrAtom) + codeLength + srcnotesLength;
uint32_t allocLength = offsetof(SharedScriptData, data_) + dataLength;
auto entry = reinterpret_cast<SharedScriptData*>(cx->zone()->pod_malloc<uint8_t>(allocLength));
if (!entry) {
ReportOutOfMemory(cx);
return nullptr;
}
entry->refCount_ = 0;
entry->dataLength_ = dataLength;
entry->natoms_ = natoms;
entry->codeLength_ = codeLength;
/*
* Call constructors to initialize the storage that will be accessed as a
* GCPtrAtom array via atoms().
*/
GCPtrAtom* atoms = entry->atoms();
MOZ_ASSERT(reinterpret_cast<uintptr_t>(atoms) % sizeof(GCPtrAtom*) == 0);
for (unsigned i = 0; i < natoms; ++i)
new (&atoms[i]) GCPtrAtom();
return entry;
}
bool
JSScript::createScriptData(ExclusiveContext* cx, uint32_t codeLength, uint32_t srcnotesLength,
uint32_t natoms)
{
MOZ_ASSERT(!scriptData());
SharedScriptData* ssd = SharedScriptData::new_(cx, codeLength, srcnotesLength, natoms);
if (!ssd)
return false;
setScriptData(ssd);
return true;
}
void
JSScript::freeScriptData()
{
MOZ_ASSERT(scriptData_->refCount() == 1);
scriptData_->decRefCount();
scriptData_ = nullptr;
}
void
JSScript::setScriptData(js::SharedScriptData* data)
{
MOZ_ASSERT(!scriptData_);
scriptData_ = data;
scriptData_->incRefCount();
}
/*
* Takes ownership of its *ssd parameter and either adds it into the runtime's
* ScriptDataTable or frees it if a matching entry already exists.
*
* Sets the |code| and |atoms| fields on the given JSScript.
*/
bool
JSScript::shareScriptData(ExclusiveContext* cx)
{
SharedScriptData* ssd = scriptData();
MOZ_ASSERT(ssd);
MOZ_ASSERT(ssd->refCount() == 1);
AutoLockForExclusiveAccess lock(cx);
ScriptBytecodeHasher::Lookup l(ssd);
ScriptDataTable::AddPtr p = cx->scriptDataTable(lock).lookupForAdd(l);
if (p) {
MOZ_ASSERT(ssd != *p);
freeScriptData();
setScriptData(*p);
} else {
if (!cx->scriptDataTable(lock).add(p, ssd)) {
freeScriptData();
ReportOutOfMemory(cx);
return false;
}
// Being in the table counts as a reference on the script data.
scriptData()->incRefCount();
}
MOZ_ASSERT(scriptData()->refCount() >= 2);
return true;
}
void
js::SweepScriptData(JSRuntime* rt, AutoLockForExclusiveAccess& lock)
{
// Entries are removed from the table when their reference count is one,
// i.e. when the only reference to them is from the table entry.
ScriptDataTable& table = rt->scriptDataTable(lock);
for (ScriptDataTable::Enum e(table); !e.empty(); e.popFront()) {
SharedScriptData* scriptData = e.front();
if (scriptData->refCount() == 1) {
scriptData->decRefCount();
e.removeFront();
}
}
}
void
js::FreeScriptData(JSRuntime* rt, AutoLockForExclusiveAccess& lock)
{
ScriptDataTable& table = rt->scriptDataTable(lock);
if (!table.initialized())
return;
// The table should be empty unless the embedding leaked GC things.
MOZ_ASSERT_IF(rt->gc.shutdownCollectedEverything(), table.empty());
for (ScriptDataTable::Enum e(table); !e.empty(); e.popFront()) {
#ifdef DEBUG
SharedScriptData* scriptData = e.front();
fprintf(stderr, "ERROR: GC found live SharedScriptData %p with ref count %d at shutdown\n",
scriptData, scriptData->refCount());
#endif
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()
* ScopeNoteArray Scope notes scopeNotes()
*
* 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
* Scope notes scopeNotes()->vector scopeNotes()->length
*
* IMPORTANT: This layout has two key properties.
* - It ensures that everything has sufficient alignment; in particular, the
* consts() elements need Value 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.
*/
template<class T>
constexpr bool
KeepsValueAlignment() {
return alignof(JS::Value) % alignof(T) == 0 &&
sizeof(T) % sizeof(JS::Value) == 0;
}
template<class T>
constexpr bool
HasValueAlignment() {
return alignof(JS::Value) == alignof(T) &&
sizeof(T) == sizeof(JS::Value);
}
template<class T1, class T2>
constexpr bool
NoPaddingBetweenEntries() {
return alignof(T1) % alignof(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
* Value-aligned. (There is an assumption that |data| itself is Value-aligned;
* we check this below).
*/
JS_STATIC_ASSERT(KeepsValueAlignment<ConstArray>());
JS_STATIC_ASSERT(KeepsValueAlignment<ObjectArray>()); /* there are two of these */
JS_STATIC_ASSERT(KeepsValueAlignment<TryNoteArray>());
JS_STATIC_ASSERT(KeepsValueAlignment<ScopeNoteArray>());
/* These assertions ensure there is no padding required between array elements. */
JS_STATIC_ASSERT(HasValueAlignment<GCPtrValue>());
JS_STATIC_ASSERT((NoPaddingBetweenEntries<GCPtrValue, GCPtrObject>()));
JS_STATIC_ASSERT((NoPaddingBetweenEntries<GCPtrObject, GCPtrObject>()));
JS_STATIC_ASSERT((NoPaddingBetweenEntries<GCPtrObject, JSTryNote>()));
JS_STATIC_ASSERT((NoPaddingBetweenEntries<JSTryNote, uint32_t>()));
JS_STATIC_ASSERT((NoPaddingBetweenEntries<uint32_t, uint32_t>()));
JS_STATIC_ASSERT((NoPaddingBetweenEntries<GCPtrValue, ScopeNote>()));
JS_STATIC_ASSERT((NoPaddingBetweenEntries<ScopeNote, ScopeNote>()));
JS_STATIC_ASSERT((NoPaddingBetweenEntries<JSTryNote, ScopeNote>()));
JS_STATIC_ASSERT((NoPaddingBetweenEntries<GCPtrObject, ScopeNote>()));
JS_STATIC_ASSERT((NoPaddingBetweenEntries<ScopeNote, uint32_t>()));
static inline size_t
ScriptDataSize(uint32_t nscopes, uint32_t nconsts, uint32_t nobjects,
uint32_t ntrynotes, uint32_t nscopenotes, uint32_t nyieldoffsets)
{
size_t size = 0;
MOZ_ASSERT(nscopes != 0);
size += sizeof(ScopeArray) + nscopes * sizeof(Scope*);
if (nconsts != 0)
size += sizeof(ConstArray) + nconsts * sizeof(Value);
if (nobjects != 0)
size += sizeof(ObjectArray) + nobjects * sizeof(NativeObject*);
if (ntrynotes != 0)
size += sizeof(TryNoteArray) + ntrynotes * sizeof(JSTryNote);
if (nscopenotes != 0)
size += sizeof(ScopeNoteArray) + nscopenotes * sizeof(ScopeNote);
if (nyieldoffsets != 0)
size += sizeof(YieldOffsetArray) + nyieldoffsets * sizeof(uint32_t);
return size;
}
void
JSScript::initCompartment(ExclusiveContext* cx)
{
compartment_ = cx->compartment_;
}
/* static */ JSScript*
JSScript::Create(ExclusiveContext* cx, const ReadOnlyCompileOptions& options,
HandleObject sourceObject, uint32_t bufStart, uint32_t bufEnd,
uint32_t preludeStart)
{
MOZ_ASSERT(bufStart <= bufEnd);
RootedScript script(cx, Allocate<JSScript>(cx));
if (!script)
return nullptr;
PodZero(script.get());
script->initCompartment(cx);
script->selfHosted_ = options.selfHostingMode;
script->noScriptRval_ = options.noScriptRval;
script->treatAsRunOnce_ = options.isRunOnce;
script->version = options.version;
MOZ_ASSERT(script->getVersion() == options.version); // assert that no overflow occurred
script->setSourceObject(sourceObject);
script->sourceStart_ = bufStart;
script->sourceEnd_ = bufEnd;
script->preludeStart_ = preludeStart;
return script;
}
static inline uint8_t*
AllocScriptData(JS::Zone* zone, size_t size)
{
if (!size)
return nullptr;
uint8_t* data = zone->pod_calloc<uint8_t>(JS_ROUNDUP(size, sizeof(Value)));
if (!data)
return nullptr;
MOZ_ASSERT(size_t(data) % sizeof(Value) == 0);
return data;
}
/* static */ bool
JSScript::partiallyInit(ExclusiveContext* cx, HandleScript script, uint32_t nscopes,
uint32_t nconsts, uint32_t nobjects, uint32_t ntrynotes,
uint32_t nscopenotes, uint32_t nyieldoffsets, uint32_t nTypeSets)
{
size_t size = ScriptDataSize(nscopes, nconsts, nobjects, ntrynotes,
nscopenotes, nyieldoffsets);
script->data = AllocScriptData(script->zone(), size);
if (size && !script->data) {
ReportOutOfMemory(cx);
return false;
}
script->dataSize_ = size;
MOZ_ASSERT(nTypeSets <= UINT16_MAX);
script->nTypeSets_ = uint16_t(nTypeSets);
uint8_t* cursor = script->data;
// There must always be at least 1 scope, the body scope.
MOZ_ASSERT(nscopes != 0);
cursor += sizeof(ScopeArray);
if (nconsts != 0) {
script->setHasArray(CONSTS);
cursor += sizeof(ConstArray);
}
if (nobjects != 0) {
script->setHasArray(OBJECTS);
cursor += sizeof(ObjectArray);
}
if (ntrynotes != 0) {
script->setHasArray(TRYNOTES);
cursor += sizeof(TryNoteArray);
}
if (nscopenotes != 0) {
script->setHasArray(SCOPENOTES);
cursor += sizeof(ScopeNoteArray);
}
YieldOffsetArray* yieldOffsets = nullptr;
if (nyieldoffsets != 0) {
yieldOffsets = reinterpret_cast<YieldOffsetArray*>(cursor);
cursor += sizeof(YieldOffsetArray);
}
if (nconsts != 0) {
MOZ_ASSERT(reinterpret_cast<uintptr_t>(cursor) % sizeof(JS::Value) == 0);
script->consts()->length = nconsts;
script->consts()->vector = (GCPtrValue*)cursor;
cursor += nconsts * sizeof(script->consts()->vector[0]);
}
script->scopes()->length = nscopes;
script->scopes()->vector = (GCPtrScope*)cursor;
cursor += nscopes * sizeof(script->scopes()->vector[0]);
if (nobjects != 0) {
script->objects()->length = nobjects;
script->objects()->vector = (GCPtrObject*)cursor;
cursor += nobjects * sizeof(script->objects()->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 (nscopenotes != 0) {
script->scopeNotes()->length = nscopenotes;
script->scopeNotes()->vector = reinterpret_cast<ScopeNote*>(cursor);
size_t vectorSize = nscopenotes * sizeof(script->scopeNotes()->vector[0]);
#ifdef DEBUG
memset(cursor, 0, vectorSize);
#endif
cursor += vectorSize;
}
if (nyieldoffsets != 0) {
yieldOffsets->init(reinterpret_cast<uint32_t*>(cursor), nyieldoffsets);
size_t vectorSize = nyieldoffsets * sizeof(script->yieldOffsets()[0]);
#ifdef DEBUG
memset(cursor, 0, vectorSize);
#endif
cursor += vectorSize;
}
MOZ_ASSERT(cursor == script->data + size);
return true;
}
/* static */ bool
JSScript::initFunctionPrototype(ExclusiveContext* cx, Handle<JSScript*> script,
HandleFunction functionProto)
{
uint32_t numScopes = 1;
uint32_t numConsts = 0;
uint32_t numObjects = 0;
uint32_t numTryNotes = 0;
uint32_t numScopeNotes = 0;
uint32_t numYieldOffsets = 0;
uint32_t numTypeSets = 0;
if (!partiallyInit(cx, script, numScopes, numConsts, numObjects, numTryNotes,
numScopeNotes, numYieldOffsets, numTypeSets))
{
return false;
}
RootedScope enclosing(cx, &cx->global()->emptyGlobalScope());
Scope* functionProtoScope = FunctionScope::create(cx, nullptr, false, false, functionProto,
enclosing);
if (!functionProtoScope)
return false;
script->scopes()->vector[0].init(functionProtoScope);
uint32_t codeLength = 1;
uint32_t srcNotesLength = 1;
uint32_t numAtoms = 0;
if (!script->createScriptData(cx, codeLength, srcNotesLength, numAtoms))
return false;
jsbytecode* code = script->code();
code[0] = JSOP_RETRVAL;
code[1] = SRC_NULL;
return script->shareScriptData(cx);
}
static void
InitAtomMap(frontend::AtomIndexMap& indices, GCPtrAtom* atoms)
{
for (AtomIndexMap::Range r = indices.all(); !r.empty(); r.popFront()) {
JSAtom* atom = r.front().key();
uint32_t index = r.front().value();
MOZ_ASSERT(index < indices.count());
atoms[index].init(atom);
}
}
/* static */ void
JSScript::initFromFunctionBox(ExclusiveContext* cx, HandleScript script,
frontend::FunctionBox* funbox)
{
JSFunction* fun = funbox->function();
if (fun->isInterpretedLazy())
fun->setUnlazifiedScript(script);
else
fun->setScript(script);
script->funHasExtensibleScope_ = funbox->hasExtensibleScope();
script->needsHomeObject_ = funbox->needsHomeObject();
script->isDerivedClassConstructor_ = funbox->isDerivedClassConstructor();
if (funbox->argumentsHasLocalBinding()) {
script->setArgumentsHasVarBinding();
if (funbox->definitelyNeedsArgsObj())
script->setNeedsArgsObj(true);
} else {
MOZ_ASSERT(!funbox->definitelyNeedsArgsObj());
}
script->hasMappedArgsObj_ = funbox->hasMappedArgsObj();
script->functionHasThisBinding_ = funbox->hasThisBinding();
script->functionHasExtraBodyVarScope_ = funbox->hasExtraBodyVarScope();
script->funLength_ = funbox->length;
script->isGeneratorExp_ = funbox->isGenexpLambda;
script->setGeneratorKind(funbox->generatorKind());
script->setAsyncKind(funbox->asyncKind());
if (funbox->hasRest())
script->setHasRest();
PositionalFormalParameterIter fi(script);
while (fi && !fi.closedOver())
fi++;
script->funHasAnyAliasedFormal_ = !!fi;
script->setHasInnerFunctions(funbox->hasInnerFunctions());
}
/* static */ void
JSScript::initFromModuleContext(ExclusiveContext* cx, HandleScript script,
frontend::ModuleSharedContext* modulesc)
{
script->funHasExtensibleScope_ = false;
script->needsHomeObject_ = false;
script->isDerivedClassConstructor_ = false;
script->funLength_ = 0;
script->isGeneratorExp_ = false;
script->setGeneratorKind(NotGenerator);
// Since modules are only run once, mark the script so that initializers
// created within it may be given more precise types.
script->setTreatAsRunOnce();
MOZ_ASSERT(!script->hasRunOnce());
}
/* static */ bool
JSScript::fullyInitFromEmitter(ExclusiveContext* cx, HandleScript script, BytecodeEmitter* bce)
{
/* The counts of indexed things must be checked during code generation. */
MOZ_ASSERT(bce->atomIndices->count() <= INDEX_LIMIT);
MOZ_ASSERT(bce->objectList.length <= INDEX_LIMIT);
uint32_t mainLength = bce->offset();
uint32_t prologueLength = bce->prologueOffset();
uint32_t nsrcnotes;
if (!bce->finishTakingSrcNotes(&nsrcnotes))
return false;
uint32_t natoms = bce->atomIndices->count();
if (!partiallyInit(cx, script,
bce->scopeList.length(), bce->constList.length(), bce->objectList.length,
bce->tryNoteList.length(), bce->scopeNoteList.length(),
bce->yieldOffsetList.length(), bce->typesetCount))
{
return false;
}
MOZ_ASSERT(script->mainOffset() == 0);
script->mainOffset_ = prologueLength;
script->lineno_ = bce->firstLine;
if (!script->createScriptData(cx, prologueLength + mainLength, nsrcnotes, natoms))
return false;
jsbytecode* code = script->code();
PodCopy<jsbytecode>(code, bce->prologue.code.begin(), prologueLength);
PodCopy<jsbytecode>(code + prologueLength, bce->main.code.begin(), mainLength);
bce->copySrcNotes((jssrcnote*)(code + script->length()), nsrcnotes);
InitAtomMap(*bce->atomIndices, script->atoms());
if (!script->shareScriptData(cx))
return false;
if (bce->constList.length() != 0)
bce->constList.finish(script->consts());
if (bce->objectList.length != 0)
bce->objectList.finish(script->objects());
if (bce->scopeList.length() != 0)
bce->scopeList.finish(script->scopes());
if (bce->tryNoteList.length() != 0)
bce->tryNoteList.finish(script->trynotes());
if (bce->scopeNoteList.length() != 0)
bce->scopeNoteList.finish(script->scopeNotes(), prologueLength);
script->strict_ = bce->sc->strict();
script->explicitUseStrict_ = bce->sc->hasExplicitUseStrict();
script->bindingsAccessedDynamically_ = bce->sc->bindingsAccessedDynamically();
script->hasSingletons_ = bce->hasSingletons;
uint64_t nslots = bce->maxFixedSlots + static_cast<uint64_t>(bce->maxStackDepth);
if (nslots > UINT32_MAX) {
bce->reportError(nullptr, JSMSG_NEED_DIET, js_script_str);
return false;
}
script->nfixed_ = bce->maxFixedSlots;
script->nslots_ = nslots;
script->bodyScopeIndex_ = bce->bodyScopeIndex;
script->hasNonSyntacticScope_ = bce->outermostScope()->hasOnChain(ScopeKind::NonSyntactic);
if (bce->sc->isFunctionBox())
initFromFunctionBox(cx, script, bce->sc->asFunctionBox());
else if (bce->sc->isModuleContext())
initFromModuleContext(cx, script, bce->sc->asModuleContext());
// Copy yield offsets last, as the generator kind is set in
// initFromFunctionBox.
if (bce->yieldOffsetList.length() != 0)
bce->yieldOffsetList.finish(script->yieldOffsets(), prologueLength);
#ifdef DEBUG
script->assertValidJumpTargets();
#endif
return true;
}
#ifdef DEBUG
void
JSScript::assertValidJumpTargets() const
{
jsbytecode* end = codeEnd();
jsbytecode* mainEntry = main();
for (jsbytecode* pc = code(); pc != end; pc = GetNextPc(pc)) {
// Check jump instructions' target.
if (IsJumpOpcode(JSOp(*pc))) {
jsbytecode* target = pc + GET_JUMP_OFFSET(pc);
MOZ_ASSERT(mainEntry <= target && target < end);
MOZ_ASSERT(BytecodeIsJumpTarget(JSOp(*target)));
// Check fallthrough of conditional jump instructions.
if (BytecodeFallsThrough(JSOp(*pc))) {
jsbytecode* fallthrough = GetNextPc(pc);
MOZ_ASSERT(mainEntry <= fallthrough && fallthrough < end);
MOZ_ASSERT(BytecodeIsJumpTarget(JSOp(*fallthrough)));
}
}
// Check table switch case labels.
if (JSOp(*pc) == JSOP_TABLESWITCH) {
jsbytecode* pc2 = pc;
int32_t len = GET_JUMP_OFFSET(pc2);
// Default target.
MOZ_ASSERT(mainEntry <= pc + len && pc + len < end);
MOZ_ASSERT(BytecodeIsJumpTarget(JSOp(*(pc + len))));
pc2 += JUMP_OFFSET_LEN;
int32_t low = GET_JUMP_OFFSET(pc2);
pc2 += JUMP_OFFSET_LEN;
int32_t high = GET_JUMP_OFFSET(pc2);
for (int i = 0; i < high - low + 1; i++) {
pc2 += JUMP_OFFSET_LEN;
int32_t off = (int32_t) GET_JUMP_OFFSET(pc2);
// Case (i + low)
MOZ_ASSERT_IF(off, mainEntry <= pc + off && pc + off < end);
MOZ_ASSERT_IF(off, BytecodeIsJumpTarget(JSOp(*(pc + off))));
}
}
}
// Check catch/finally blocks as jump targets.
if (hasTrynotes()) {
JSTryNote* tn = trynotes()->vector;
JSTryNote* tnlimit = tn + trynotes()->length;
for (; tn < tnlimit; tn++) {
jsbytecode* tryStart = mainEntry + tn->start;
jsbytecode* tryPc = tryStart - 1;
if (tn->kind != JSTRY_CATCH && tn->kind != JSTRY_FINALLY)
continue;
MOZ_ASSERT(JSOp(*tryPc) == JSOP_TRY);
jsbytecode* tryTarget = tryStart + tn->length;
MOZ_ASSERT(mainEntry <= tryTarget && tryTarget < end);
MOZ_ASSERT(BytecodeIsJumpTarget(JSOp(*tryTarget)));
}
}
}
#endif
size_t
JSScript::computedSizeOfData() const
{
return dataSize();
}
size_t
JSScript::sizeOfData(mozilla::MallocSizeOf mallocSizeOf) const
{
return mallocSizeOf(data);
}
size_t
JSScript::sizeOfTypeScript(mozilla::MallocSizeOf mallocSizeOf) const
{
return types_->sizeOfIncludingThis(mallocSizeOf);
}
/*
* 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 */
}
js::GlobalObject&
JSScript::uninlinedGlobal() const
{
return global();
}
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().
// Collect code coverage information for this script and all its inner
// scripts, and store the aggregated information on the compartment.
if (fop->runtime()->lcovOutput.isEnabled())
compartment()->lcovOutput.collectCodeCoverageInfo(compartment(), sourceObject(), this);
fop->runtime()->spsProfiler.onScriptFinalized(this);
if (types_)
types_->destroy();
jit::DestroyJitScripts(fop, this);
destroyScriptCounts(fop);
destroyDebugScript(fop);
if (data) {
JS_POISON(data, 0xdb, computedSizeOfData());
fop->free_(data);
}
if (scriptData_)
scriptData_->decRefCount();
fop->runtime()->contextFromMainThread()->caches.lazyScriptCache.remove(this);
// In most cases, our LazyScript's script pointer will reference this
// script, and thus be nulled out by normal weakref processing. However, if
// we unlazified the LazyScript during incremental sweeping, it will have a
// completely different JSScript.
MOZ_ASSERT_IF(lazyScript && !IsAboutToBeFinalizedUnbarriered(&lazyScript),
!lazyScript->hasScript() || lazyScript->maybeScriptUnbarriered() != this);
}
static const uint32_t GSN_CACHE_THRESHOLD = 100;
void
GSNCache::purge()
{
code = nullptr;
if (map.initialized())
map.finish();
}
jssrcnote*
js::GetSrcNote(GSNCache& cache, JSScript* script, jsbytecode* pc)
{
size_t target = pc - script->code();
if (target >= script->length())
return nullptr;
if (cache.code == script->code()) {
MOZ_ASSERT(cache.map.initialized());
GSNCache::Map::Ptr p = cache.map.lookup(pc);
return p ? p->value() : nullptr;
}
size_t offset = 0;
jssrcnote* result;
for (jssrcnote* sn = script->notes(); ; sn = SN_NEXT(sn)) {
if (SN_IS_TERMINATOR(sn)) {
result = nullptr;
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) {
MOZ_ASSERT(cache.map.initialized());
cache.map.finish();
cache.code = nullptr;
}
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))
cache.map.putNewInfallible(pc, sn);
}
cache.code = script->code();
}
}
return result;
}
jssrcnote*
js::GetSrcNote(JSContext* cx, JSScript* script, jsbytecode* pc)
{
return GetSrcNote(cx->caches.gsnCache, script, pc);
}
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);
if (offset > target)
break;
SrcNoteType type = (SrcNoteType) SN_TYPE(sn);
if (type == SRC_SETLINE) {
lineno = unsigned(GetSrcNoteOffset(sn, 0));
column = 0;
} else if (type == SRC_NEWLINE) {
lineno++;
column = 0;
} else if (type == SRC_COLSPAN) {
ptrdiff_t colspan = SN_OFFSET_TO_COLSPAN(GetSrcNoteOffset(sn, 0));
MOZ_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 InterpreterFrame.pc value prior to entering Interpret. */
if (!pc)
return 0;
return PCToLineNumber(script->lineno(), script->notes(), script->code(), pc, columnp);
}
jsbytecode*
js::LineNumberToPC(JSScript* script, unsigned target)
{
ptrdiff_t offset = 0;
ptrdiff_t best = -1;
unsigned lineno = script->lineno();
unsigned bestdiff = SN_MAX_OFFSET;
for (jssrcnote* sn = script->notes(); !SN_IS_TERMINATOR(sn); sn = SN_NEXT(sn)) {
/*
* Exact-match only if offset is not in the prologue; 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(GetSrcNoteOffset(sn, 0));
} else if (type == SRC_NEWLINE) {
lineno++;
}
}
if (best >= 0)
offset = best;
out:
return script->offsetToPC(offset);
}
JS_FRIEND_API(unsigned)
js::GetScriptLineExtent(JSScript* script)
{
unsigned lineno = script->lineno();
unsigned maxLineNo = lineno;
for (jssrcnote* sn = script->notes(); !SN_IS_TERMINATOR(sn); sn = SN_NEXT(sn)) {
SrcNoteType type = (SrcNoteType) SN_TYPE(sn);
if (type == SRC_SETLINE)
lineno = unsigned(GetSrcNoteOffset(sn, 0));
else if (type == SRC_NEWLINE)
lineno++;
if (maxLineNo < lineno)
maxLineNo = lineno;
}
return 1 + maxLineNo - script->lineno();
}
void
js::DescribeScriptedCallerForCompilation(JSContext* cx, MutableHandleScript maybeScript,
const char** file, unsigned* linenop,
uint32_t* pcOffset, bool* mutedErrors,
LineOption opt)
{
if (opt == CALLED_FROM_JSOP_EVAL) {
jsbytecode* pc = nullptr;
maybeScript.set(cx->currentScript(&pc));
static_assert(JSOP_SPREADEVAL_LENGTH == JSOP_STRICTSPREADEVAL_LENGTH,
"next op after a spread must be at consistent offset");
static_assert(JSOP_EVAL_LENGTH == JSOP_STRICTEVAL_LENGTH,
"next op after a direct eval must be at consistent offset");
MOZ_ASSERT(JSOp(*pc) == JSOP_EVAL || JSOp(*pc) == JSOP_STRICTEVAL ||
JSOp(*pc) == JSOP_SPREADEVAL || JSOp(*pc) == JSOP_STRICTSPREADEVAL);
bool isSpread = JSOp(*pc) == JSOP_SPREADEVAL || JSOp(*pc) == JSOP_STRICTSPREADEVAL;
jsbytecode* nextpc = pc + (isSpread ? JSOP_SPREADEVAL_LENGTH : JSOP_EVAL_LENGTH);
MOZ_ASSERT(*nextpc == JSOP_LINENO);
*file = maybeScript->filename();
*linenop = GET_UINT32(nextpc);
*pcOffset = pc - maybeScript->code();
*mutedErrors = maybeScript->mutedErrors();
return;
}
NonBuiltinFrameIter iter(cx, cx->compartment()->principals());
if (iter.done()) {
maybeScript.set(nullptr);
*file = nullptr;
*linenop = 0;
*pcOffset = 0;
*mutedErrors = false;
return;
}
*file = iter.filename();
*linenop = iter.computeLine();
*mutedErrors = iter.mutedErrors();
// These values are only used for introducer fields which are debugging
// information and can be safely left null for wasm frames.
if (iter.hasScript()) {
maybeScript.set(iter.script());
*pcOffset = iter.pc() - maybeScript->code();
} else {
maybeScript.set(nullptr);
*pcOffset = 0;
}
}
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);
}
static JSObject*
CloneInnerInterpretedFunction(JSContext* cx, HandleScope enclosingScope, HandleFunction srcFun)
{
/* NB: Keep this in sync with XDRInterpretedFunction. */
RootedObject cloneProto(cx);
if (srcFun->isStarGenerator()) {
cloneProto = GlobalObject::getOrCreateStarGeneratorFunctionPrototype(cx, cx->global());
if (!cloneProto)
return nullptr;
}
gc::AllocKind allocKind = srcFun->getAllocKind();
uint16_t flags = srcFun->flags();
if (srcFun->isSelfHostedBuiltin()) {
// Functions in the self-hosting compartment are only extended in
// debug mode. For top-level functions, FUNCTION_EXTENDED gets used by
// the cloning algorithm. Do the same for inner functions here.
allocKind = gc::AllocKind::FUNCTION_EXTENDED;
flags |= JSFunction::Flags::EXTENDED;
}
RootedAtom atom(cx, srcFun->displayAtom());
RootedFunction clone(cx, NewFunctionWithProto(cx, nullptr, srcFun->nargs(),
JSFunction::Flags(flags), nullptr, atom,
cloneProto, allocKind, TenuredObject));
if (!clone)
return nullptr;
JSScript::AutoDelazify srcScript(cx, srcFun);
if (!srcScript)
return nullptr;
JSScript* cloneScript = CloneScriptIntoFunction(cx, enclosingScope, clone, srcScript);
if (!cloneScript)
return nullptr;
if (!JSFunction::setTypeForScriptedFunction(cx, clone))
return nullptr;
return clone;
}
bool
js::detail::CopyScript(JSContext* cx, HandleScript src, HandleScript dst,
MutableHandle<GCVector<Scope*>> scopes)
{
if (src->treatAsRunOnce() && !src->functionNonDelazifying()) {
JS_ReportErrorASCII(cx, "No cloning toplevel run-once scripts");
return false;
}
/* NB: Keep this in sync with XDRScript. */
/* Some embeddings are not careful to use ExposeObjectToActiveJS as needed. */
MOZ_ASSERT(!src->sourceObject()->asTenured().isMarked(gc::GRAY));
uint32_t nconsts = src->hasConsts() ? src->consts()->length : 0;
uint32_t nobjects = src->hasObjects() ? src->objects()->length : 0;
uint32_t nscopes = src->scopes()->length;
uint32_t ntrynotes = src->hasTrynotes() ? src->trynotes()->length : 0;
uint32_t nscopenotes = src->hasScopeNotes() ? src->scopeNotes()->length : 0;
uint32_t nyieldoffsets = src->hasYieldOffsets() ? src->yieldOffsets().length() : 0;
/* Script data */
size_t size = src->dataSize();
ScopedJSFreePtr<uint8_t> data(AllocScriptData(cx->zone(), size));
if (size && !data) {
ReportOutOfMemory(cx);
return false;
}
/* Scopes */
// The passed in scopes vector contains body scopes that needed to be
// cloned especially, depending on whether the script is a function or
// global scope. Starting at scopes.length() means we only deal with
// intra-body scopes.
{
MOZ_ASSERT(nscopes != 0);
MOZ_ASSERT(src->bodyScopeIndex() + 1 == scopes.length());
GCPtrScope* vector = src->scopes()->vector;
RootedScope original(cx);
RootedScope clone(cx);
for (uint32_t i = scopes.length(); i < nscopes; i++) {
original = vector[i];
clone = Scope::clone(cx, original, scopes[FindScopeIndex(src, *original->enclosing())]);
if (!clone || !scopes.append(clone))
return false;
}
}
/* Objects */
AutoObjectVector objects(cx);
if (nobjects != 0) {
GCPtrObject* vector = src->objects()->vector;
RootedObject obj(cx);
RootedObject clone(cx);
for (unsigned i = 0; i < nobjects; i++) {
obj = vector[i];
clone = nullptr;
if (obj->is<RegExpObject>()) {
clone = CloneScriptRegExpObject(cx, obj->as<RegExpObject>());
} else if (obj->is<JSFunction>()) {
RootedFunction innerFun(cx, &obj->as<JSFunction>());
if (innerFun->isNative()) {
if (cx->compartment() != innerFun->compartment()) {
MOZ_ASSERT(innerFun->isAsmJSNative());
JS_ReportErrorASCII(cx, "AsmJS modules do not yet support cloning.");
return false;
}
clone = innerFun;
} else {
if (innerFun->isInterpretedLazy()) {
AutoCompartment ac(cx, innerFun);
if (!innerFun->getOrCreateScript(cx))
return false;
}
Scope* enclosing = innerFun->nonLazyScript()->enclosingScope();
RootedScope enclosingClone(cx, scopes[FindScopeIndex(src, *enclosing)]);
clone = CloneInnerInterpretedFunction(cx, enclosingClone, innerFun);
}
} else {
clone = DeepCloneObjectLiteral(cx, obj, TenuredObject);
}
if (!clone || !objects.append(clone))
return false;
}
}
/* This assignment must occur before all the Rebase calls. */
dst->data = data.forget();
dst->dataSize_ = size;
MOZ_ASSERT(bool(dst->data) == bool(src->data));
if (dst->data)
memcpy(dst->data, src->data, size);
/* Script filenames, bytecodes and atoms are runtime-wide. */
dst->setScriptData(src->scriptData());
dst->lineno_ = src->lineno();
dst->mainOffset_ = src->mainOffset();
dst->nfixed_ = src->nfixed();
dst->nslots_ = src->nslots();
dst->bodyScopeIndex_ = src->bodyScopeIndex_;
dst->funLength_ = src->funLength();
dst->nTypeSets_ = src->nTypeSets();
if (src->argumentsHasVarBinding()) {
dst->setArgumentsHasVarBinding();
if (src->analyzedArgsUsage())
dst->setNeedsArgsObj(src->needsArgsObj());
}
dst->hasMappedArgsObj_ = src->hasMappedArgsObj();
dst->functionHasThisBinding_ = src->functionHasThisBinding();
dst->functionHasExtraBodyVarScope_ = src->functionHasExtraBodyVarScope();
dst->cloneHasArray(src);
dst->strict_ = src->strict();
dst->explicitUseStrict_ = src->explicitUseStrict();
dst->hasNonSyntacticScope_ = scopes[0]->hasOnChain(ScopeKind::NonSyntactic);
dst->bindingsAccessedDynamically_ = src->bindingsAccessedDynamically();
dst->funHasExtensibleScope_ = src->funHasExtensibleScope();
dst->funHasAnyAliasedFormal_ = src->funHasAnyAliasedFormal();
dst->hasSingletons_ = src->hasSingletons();
dst->treatAsRunOnce_ = src->treatAsRunOnce();
dst->hasInnerFunctions_ = src->hasInnerFunctions();
dst->isGeneratorExp_ = src->isGeneratorExp();
dst->setGeneratorKind(src->generatorKind());
dst->isDerivedClassConstructor_ = src->isDerivedClassConstructor();
dst->needsHomeObject_ = src->needsHomeObject();
dst->isDefaultClassConstructor_ = src->isDefaultClassConstructor();
dst->isAsync_ = src->asyncKind() == AsyncFunction;
dst->hasRest_ = src->hasRest_;
if (nconsts != 0) {
GCPtrValue* vector = Rebase<GCPtrValue>(dst, src, src->consts()->vector);
dst->consts()->vector = vector;
for (unsigned i = 0; i < nconsts; ++i)
MOZ_ASSERT_IF(vector[i].isGCThing(), vector[i].toString()->isAtom());
}
if (nobjects != 0) {
GCPtrObject* vector = Rebase<GCPtrObject>(dst, src, src->objects()->vector);
dst->objects()->vector = vector;
for (unsigned i = 0; i < nobjects; ++i)
vector[i].init(&objects[i]->as<NativeObject>());
}
{
GCPtrScope* vector = Rebase<GCPtrScope>(dst, src, src->scopes()->vector);
dst->scopes()->vector = vector;
for (uint32_t i = 0; i < nscopes; ++i)
vector[i].init(scopes[i]);
}
if (ntrynotes != 0)
dst->trynotes()->vector = Rebase<JSTryNote>(dst, src, src->trynotes()->vector);
if (nscopenotes != 0)
dst->scopeNotes()->vector = Rebase<ScopeNote>(dst, src, src->scopeNotes()->vector);
if (nyieldoffsets != 0)
dst->yieldOffsets().vector_ = Rebase<uint32_t>(dst, src, src->yieldOffsets().vector_);
/*
* Function delazification assumes that their script does not have a
* non-syntactic global scope. We ensure that as follows:
*
* 1) Initial parsing only creates lazy functions if
* !hasNonSyntacticScope.
* 2) Cloning a lazy function into a non-global scope will always require
* that its script be cloned. See comments in
* CloneFunctionObjectUseSameScript.
* 3) Cloning a script never sets a lazyScript on the clone, so the function
* cannot be relazified.
*
* If you decide that lazy functions should be supported with a
* non-syntactic global scope, make sure delazification can deal.
*/
MOZ_ASSERT_IF(dst->hasNonSyntacticScope(), !dst->maybeLazyScript());
MOZ_ASSERT_IF(dst->hasNonSyntacticScope(), !dst->isRelazifiable());
return true;
}
static JSScript*
CreateEmptyScriptForClone(JSContext* cx, HandleScript src)
{
/*
* Wrap the script source object as needed. Self-hosted scripts may be
* in another runtime, so lazily create a new script source object to
* use for them.
*/
RootedObject sourceObject(cx);
if (cx->runtime()->isSelfHostingCompartment(src->compartment())) {
if (!cx->compartment()->selfHostingScriptSource) {
CompileOptions options(cx);
FillSelfHostingCompileOptions(options);
ScriptSourceObject* obj = frontend::CreateScriptSourceObject(cx, options);
if (!obj)
return nullptr;
cx->compartment()->selfHostingScriptSource.set(obj);
}
sourceObject = cx->compartment()->selfHostingScriptSource;
} else {
sourceObject = src->sourceObject();
if (!cx->compartment()->wrap(cx, &sourceObject))
return nullptr;
}
CompileOptions options(cx);
options.setMutedErrors(src->mutedErrors())
.setSelfHostingMode(src->selfHosted())
.setNoScriptRval(src->noScriptRval())
.setVersion(src->getVersion());
return JSScript::Create(cx, options, sourceObject, src->sourceStart(), src->sourceEnd(),
src->preludeStart());
}
JSScript*
js::CloneGlobalScript(JSContext* cx, ScopeKind scopeKind, HandleScript src)
{
MOZ_ASSERT(scopeKind == ScopeKind::Global || scopeKind == ScopeKind::NonSyntactic);
RootedScript dst(cx, CreateEmptyScriptForClone(cx, src));
if (!dst)
return nullptr;
MOZ_ASSERT(src->bodyScopeIndex() == 0);
Rooted<GCVector<Scope*>> scopes(cx, GCVector<Scope*>(cx));
Rooted<GlobalScope*> original(cx, &src->bodyScope()->as<GlobalScope>());
GlobalScope* clone = GlobalScope::clone(cx, original, scopeKind);
if (!clone || !scopes.append(clone))
return nullptr;
if (!detail::CopyScript(cx, src, dst, &scopes))
return nullptr;
return dst;
}
JSScript*
js::CloneScriptIntoFunction(JSContext* cx, HandleScope enclosingScope, HandleFunction fun,
HandleScript src)
{
MOZ_ASSERT(fun->isInterpreted());
MOZ_ASSERT(!fun->hasScript() || fun->hasUncompiledScript());
RootedScript dst(cx, CreateEmptyScriptForClone(cx, src));
if (!dst)
return nullptr;
// Clone the non-intra-body scopes.
Rooted<GCVector<Scope*>> scopes(cx, GCVector<Scope*>(cx));
RootedScope original(cx);
RootedScope enclosingClone(cx);
for (uint32_t i = 0; i <= src->bodyScopeIndex(); i++) {
original = src->getScope(i);
if (i == 0) {
enclosingClone = enclosingScope;
} else {
MOZ_ASSERT(src->getScope(i - 1) == original->enclosing());
enclosingClone = scopes[i - 1];
}
Scope* clone;
if (original->is<FunctionScope>())
clone = FunctionScope::clone(cx, original.as<FunctionScope>(), fun, enclosingClone);
else
clone = Scope::clone(cx, original, enclosingClone);
if (!clone || !scopes.append(clone))
return nullptr;
}
// Save flags in case we need to undo the early mutations.
const int preservedFlags = fun->flags();
if (!detail::CopyScript(cx, src, dst, &scopes)) {
fun->setFlags(preservedFlags);
return nullptr;
}
// Finally set the script after all the fallible operations.
if (fun->isInterpretedLazy())
fun->setUnlazifiedScript(dst);
else
fun->initScript(dst);
return dst;
}
DebugScript*
JSScript::debugScript()
{
MOZ_ASSERT(hasDebugScript_);
DebugScriptMap* map = compartment()->debugScriptMap;
MOZ_ASSERT(map);
DebugScriptMap::Ptr p = map->lookup(this);
MOZ_ASSERT(p);
return p->value();
}
DebugScript*
JSScript::releaseDebugScript()
{
MOZ_ASSERT(hasDebugScript_);
DebugScriptMap* map = compartment()->debugScriptMap;
MOZ_ASSERT(map);
DebugScriptMap::Ptr p = map->lookup(this);
MOZ_ASSERT(p);
DebugScript* debug = p->value();
map->remove(p);
hasDebugScript_ = false;
return debug;
}
void
JSScript::destroyDebugScript(FreeOp* fop)
{
if (hasDebugScript_) {
#ifdef DEBUG
for (jsbytecode* pc = code(); pc < codeEnd(); pc++) {
if (BreakpointSite* site = getBreakpointSite(pc)) {
/* Breakpoints are swept before finalization. */
MOZ_ASSERT(site->firstBreakpoint() == nullptr);
MOZ_ASSERT(getBreakpointSite(pc) == nullptr);
}
}
#endif
fop->free_(releaseDebugScript());
}
}
bool
JSScript::ensureHasDebugScript(JSContext* cx)
{
if (hasDebugScript_)
return true;
size_t nbytes = offsetof(DebugScript, breakpoints) + length() * sizeof(BreakpointSite*);
DebugScript* debug = (DebugScript*) zone()->pod_calloc<uint8_t>(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.
*/
for (ActivationIterator iter(cx->runtime()); !iter.done(); ++iter) {
if (iter->isInterpreter())
iter->asInterpreter()->enableInterruptsIfRunning(this);
}
return true;
}
void
JSScript::setNewStepMode(FreeOp* fop, uint32_t newValue)
{
DebugScript* debug = debugScript();
uint32_t prior = debug->stepMode;
debug->stepMode = newValue;
if (!prior != !newValue) {
if (hasBaselineScript())
baseline->toggleDebugTraps(this, nullptr);
if (!stepModeEnabled() && !debug->numSites)
fop->free_(releaseDebugScript());
}
}
bool
JSScript::incrementStepModeCount(JSContext* cx)
{
assertSameCompartment(cx, this);
MOZ_ASSERT(cx->compartment()->isDebuggee());
if (!ensureHasDebugScript(cx))
return false;
DebugScript* debug = debugScript();
uint32_t count = debug->stepMode;
setNewStepMode(cx->runtime()->defaultFreeOp(), count + 1);
return true;
}
void
JSScript::decrementStepModeCount(FreeOp* fop)
{
DebugScript* debug = debugScript();
uint32_t count = debug->stepMode;
MOZ_ASSERT(count > 0);
setNewStepMode(fop, count - 1);
}
BreakpointSite*
JSScript::getOrCreateBreakpointSite(JSContext* cx, jsbytecode* pc)
{
if (!ensureHasDebugScript(cx))
return nullptr;
DebugScript* debug = debugScript();
BreakpointSite*& site = debug->breakpoints[pcToOffset(pc)];
if (!site) {
site = cx->runtime()->new_<BreakpointSite>(this, pc);
if (!site) {
ReportOutOfMemory(cx);
return nullptr;
}
debug->numSites++;
}
return site;
}
void
JSScript::destroyBreakpointSite(FreeOp* fop, jsbytecode* pc)
{
DebugScript* debug = debugScript();
BreakpointSite*& site = debug->breakpoints[pcToOffset(pc)];
MOZ_ASSERT(site);
fop->delete_(site);
site = nullptr;
if (--debug->numSites == 0 && !stepModeEnabled())
fop->free_(releaseDebugScript());
}
void
JSScript::clearBreakpointsIn(FreeOp* fop, js::Debugger* dbg, JSObject* handler)
{
if (!hasAnyBreakpointsOrStepMode())
return;
for (jsbytecode* pc = code(); pc < codeEnd(); 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;
}
void
SharedScriptData::traceChildren(JSTracer* trc)
{
MOZ_ASSERT(refCount() != 0);
for (uint32_t i = 0; i < natoms(); ++i)
TraceNullableEdge(trc, &atoms()[i], "atom");
}
void
JSScript::traceChildren(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().
MOZ_ASSERT_IF(trc->isMarkingTracer() &&
static_cast<GCMarker*>(trc)->shouldCheckCompartments(),
zone()->isCollecting());
if (scriptData())
scriptData()->traceChildren(trc);
if (ScopeArray* scopearray = scopes())
TraceRange(trc, scopearray->length, scopearray->vector, "scopes");
if (hasConsts()) {
ConstArray* constarray = consts();
TraceRange(trc, constarray->length, constarray->vector, "consts");
}
if (hasObjects()) {
ObjectArray* objarray = objects();
TraceRange(trc, objarray->length, objarray->vector, "objects");
}
MOZ_ASSERT_IF(sourceObject(), MaybeForwarded(sourceObject())->compartment() == compartment());
TraceNullableEdge(trc, &sourceObject_, "sourceObject");
if (maybeLazyScript())
TraceManuallyBarrieredEdge(trc, &lazyScript, "lazyScript");
if (trc->isMarkingTracer())
compartment()->mark();
jit::TraceJitScripts(trc, this);
}
void
LazyScript::finalize(FreeOp* fop)
{
fop->free_(table_);
}
size_t
JSScript::calculateLiveFixed(jsbytecode* pc)
{
size_t nlivefixed = numAlwaysLiveFixedSlots();
if (nfixed() != nlivefixed) {
Scope* scope = lookupScope(pc);
if (scope)
scope = MaybeForwarded(scope);
// Find the nearest LexicalScope in the same script.
while (scope && scope->is<WithScope>()) {
scope = scope->enclosing();
if (scope)
scope = MaybeForwarded(scope);
}
if (scope) {
if (scope->is<LexicalScope>())
nlivefixed = scope->as<LexicalScope>().nextFrameSlot();
else if (scope->is<VarScope>())
nlivefixed = scope->as<VarScope>().nextFrameSlot();
}
}
MOZ_ASSERT(nlivefixed <= nfixed());
MOZ_ASSERT(nlivefixed >= numAlwaysLiveFixedSlots());
return nlivefixed;
}
Scope*
JSScript::lookupScope(jsbytecode* pc)
{
MOZ_ASSERT(containsPC(pc));
if (!hasScopeNotes())
return nullptr;
size_t offset = pc - code();
ScopeNoteArray* notes = scopeNotes();
Scope* scope = nullptr;
// Find the innermost block chain using a binary search.
size_t bottom = 0;
size_t top = notes->length;
while (bottom < top) {
size_t mid = bottom + (top - bottom) / 2;
const ScopeNote* note = &notes->vector[mid];
if (note->start <= offset) {
// Block scopes are ordered in the list by their starting offset, and since
// blocks form a tree ones earlier in the list may cover the pc even if
// later blocks end before the pc. This only happens when the earlier block
// is a parent of the later block, so we need to check parents of |mid| in
// the searched range for coverage.
size_t check = mid;
while (check >= bottom) {
const ScopeNote* checkNote = &notes->vector[check];
MOZ_ASSERT(checkNote->start <= offset);
if (offset < checkNote->start + checkNote->length) {
// We found a matching block chain but there may be inner ones
// at a higher block chain index than mid. Continue the binary search.
if (checkNote->index == ScopeNote::NoScopeIndex)
scope = nullptr;
else
scope = getScope(checkNote->index);
break;
}
if (checkNote->parent == UINT32_MAX)
break;
check = checkNote->parent;
}
bottom = mid + 1;
} else {
top = mid;
}
}
return scope;
}
Scope*
JSScript::innermostScope(jsbytecode* pc)
{
if (Scope* scope = lookupScope(pc))
return scope;
return bodyScope();
}
void
JSScript::setArgumentsHasVarBinding()
{
argsHasVarBinding_ = true;
needsArgsAnalysis_ = true;
}
void
JSScript::setNeedsArgsObj(bool needsArgsObj)
{
MOZ_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.
*/
Rooted<BindingIter> bi(cx, BindingIter(script));
while (bi && bi.name() != cx->names().arguments)
bi++;
if (!bi)
return;
if (bi.location().kind() == BindingLocation::Kind::Environment) {
/*
* 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;
MOZ_ASSERT(*pc == JSOP_SETALIASEDVAR);
// Note that here and below, it is insufficient to only check for
// JS_OPTIMIZED_ARGUMENTS, as Ion could have optimized out the
// arguments slot.
EnvironmentObject& env = frame.callObj().as<EnvironmentObject>();
if (IsOptimizedPlaceholderMagicValue(env.aliasedBinding(bi)))
env.setAliasedBinding(cx, bi, ObjectValue(*argsobj));
} else {
MOZ_ASSERT(bi.location().kind() == BindingLocation::Kind::Frame);
uint32_t frameSlot = bi.location().slot();
if (IsOptimizedPlaceholderMagicValue(frame.unaliasedLocal(frameSlot)))
frame.unaliasedLocal(frameSlot) = ObjectValue(*argsobj);
}
}
/* static */ bool
JSScript::argumentsOptimizationFailed(JSContext* cx, HandleScript script)
{
MOZ_ASSERT(script->functionNonDelazifying());
MOZ_ASSERT(script->analyzedArgsUsage());
MOZ_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;
MOZ_ASSERT(!script->isGenerator());
script->needsArgsObj_ = true;
/*
* 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();
/*
* 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 (AllScriptFramesIter 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 BaselineFrame and before
* entering Baseline code (in jit::FinishBailoutToBaseline).
*/
if (i.isIon())
continue;
AbstractFramePtr frame = i.abstractFramePtr();
if (frame.isFunctionFrame() && frame.script() == script) {
/* We crash on OOM since cleaning up here would be complicated. */
AutoEnterOOMUnsafeRegion oomUnsafe;
ArgumentsObject* argsobj = ArgumentsObject::createExpected(cx, frame);
if (!argsobj)
oomUnsafe.crash("JSScript::argumentsOptimizationFailed");
SetFrameArgumentsObject(cx, frame, script, argsobj);
}
}
return true;
}
bool
JSScript::formalIsAliased(unsigned argSlot)
{
if (functionHasParameterExprs())
return false;
for (PositionalFormalParameterIter fi(this); fi; fi++) {
if (fi.argumentSlot() == argSlot)
return fi.closedOver();
}
MOZ_CRASH("Argument slot not found");
}
bool
JSScript::formalLivesInArgumentsObject(unsigned argSlot)
{
return argsObjAliasesFormals() && !formalIsAliased(argSlot);
}
LazyScript::LazyScript(JSFunction* fun, void* table, uint64_t packedFields,
uint32_t begin, uint32_t end,
uint32_t preludeStart, uint32_t lineno, uint32_t column)
: script_(nullptr),
function_(fun),
enclosingScope_(nullptr),
sourceObject_(nullptr),
table_(table),
packedFields_(packedFields),
begin_(begin),
end_(end),
preludeStart_(preludeStart),
lineno_(lineno),
column_(column)
{
MOZ_ASSERT(begin <= end);
}
void
LazyScript::initScript(JSScript* script)
{
MOZ_ASSERT(script);
MOZ_ASSERT(!script_.unbarrieredGet());
script_.set(script);
}
void
LazyScript::resetScript()
{
MOZ_ASSERT(script_.unbarrieredGet());
script_.set(nullptr);
}
void
LazyScript::setEnclosingScopeAndSource(Scope* enclosingScope, ScriptSourceObject* sourceObject)
{
MOZ_ASSERT(function_->compartment() == sourceObject->compartment());
// This method may be called to update the enclosing scope. See comment
// above the callsite in BytecodeEmitter::emitFunction.
MOZ_ASSERT_IF(sourceObject_, sourceObject_ == sourceObject && enclosingScope_);
MOZ_ASSERT_IF(!sourceObject_, !enclosingScope_);
enclosingScope_ = enclosingScope;
sourceObject_ = sourceObject;
}
ScriptSourceObject*
LazyScript::sourceObject() const
{
return sourceObject_ ? &sourceObject_->as<ScriptSourceObject>() : nullptr;
}
ScriptSource*
LazyScript::maybeForwardedScriptSource() const
{
return UncheckedUnwrap(MaybeForwarded(sourceObject()))->as<ScriptSourceObject>().source();
}
/* static */ LazyScript*
LazyScript::CreateRaw(ExclusiveContext* cx, HandleFunction fun,
uint64_t packedFields, uint32_t begin, uint32_t end,
uint32_t preludeStart, uint32_t lineno, uint32_t column)
{
union {
PackedView p;
uint64_t packed;
};
packed = packedFields;
// Reset runtime flags to obtain a fresh LazyScript.
p.hasBeenCloned = false;
p.treatAsRunOnce = false;
size_t bytes = (p.numClosedOverBindings * sizeof(JSAtom*))
+ (p.numInnerFunctions * sizeof(GCPtrFunction));
ScopedJSFreePtr<uint8_t> table(bytes ? fun->zone()->pod_malloc<uint8_t>(bytes) : nullptr);
if (bytes && !table) {
ReportOutOfMemory(cx);
return nullptr;
}
LazyScript* res = Allocate<LazyScript>(cx);
if (!res)
return nullptr;
cx->compartment()->scheduleDelazificationForDebugger();
return new (res) LazyScript(fun, table.forget(), packed, begin, end,
preludeStart, lineno, column);
}
/* static */ LazyScript*
LazyScript::Create(ExclusiveContext* cx, HandleFunction fun,
const frontend::AtomVector& closedOverBindings,
Handle<GCVector<JSFunction*, 8>> innerFunctions,
JSVersion version,
uint32_t begin, uint32_t end,
uint32_t preludeStart, uint32_t lineno, uint32_t column)
{
union {
PackedView p;
uint64_t packedFields;
};
p.version = version;
p.shouldDeclareArguments = false;
p.hasThisBinding = false;
p.isAsync = false;
p.hasRest = false;
p.numClosedOverBindings = closedOverBindings.length();
p.numInnerFunctions = innerFunctions.length();
p.generatorKindBits = GeneratorKindAsBits(NotGenerator);
p.strict = false;
p.bindingsAccessedDynamically = false;
p.hasDebuggerStatement = false;
p.hasDirectEval = false;
p.isLikelyConstructorWrapper = false;
p.isDerivedClassConstructor = false;
p.needsHomeObject = false;
LazyScript* res = LazyScript::CreateRaw(cx, fun, packedFields, begin, end, preludeStart,
lineno, column);
if (!res)
return nullptr;
JSAtom** resClosedOverBindings = res->closedOverBindings();
for (size_t i = 0; i < res->numClosedOverBindings(); i++)
resClosedOverBindings[i] = closedOverBindings[i];
GCPtrFunction* resInnerFunctions = res->innerFunctions();
for (size_t i = 0; i < res->numInnerFunctions(); i++)
resInnerFunctions[i].init(innerFunctions[i]);
MOZ_ASSERT_IF(res, res->version() == version);
return res;
}
/* static */ LazyScript*
LazyScript::Create(ExclusiveContext* cx, HandleFunction fun,
HandleScript script, HandleScope enclosingScope,
HandleScript enclosingScript,
uint64_t packedFields, uint32_t begin, uint32_t end,
uint32_t preludeStart, uint32_t lineno, uint32_t column)
{
// Dummy atom which is not a valid property name.
RootedAtom dummyAtom(cx, cx->names().comma);
// Dummy function which is not a valid function as this is the one which is
// holding this lazy script.
HandleFunction dummyFun = fun;
LazyScript* res = LazyScript::CreateRaw(cx, fun, packedFields, begin, end, preludeStart,
lineno, column);
if (!res)
return nullptr;
// Fill with dummies, to be GC-safe after the initialization of the free
// variables and inner functions.
size_t i, num;
JSAtom** closedOverBindings = res->closedOverBindings();
for (i = 0, num = res->numClosedOverBindings(); i < num; i++)
closedOverBindings[i] = dummyAtom;
GCPtrFunction* functions = res->innerFunctions();
for (i = 0, num = res->numInnerFunctions(); i < num; i++)
functions[i].init(dummyFun);
// Set the enclosing scope and source object of the lazy function. These
// values should only be non-null if we have a non-lazy enclosing script.
// AddLazyFunctionsForCompartment relies on the source object being null
// if we're nested inside another lazy function.
MOZ_ASSERT(!!enclosingScript == !!enclosingScope);
MOZ_ASSERT(!res->sourceObject());
MOZ_ASSERT(!res->enclosingScope());
if (enclosingScript)
res->setEnclosingScopeAndSource(enclosingScope, &enclosingScript->scriptSourceUnwrap());
MOZ_ASSERT(!res->hasScript());
if (script)
res->initScript(script);
return res;
}
void
LazyScript::initRuntimeFields(uint64_t packedFields)
{
union {
PackedView p;
uint64_t packed;
};
packed = packedFields;
p_.hasBeenCloned = p.hasBeenCloned;
p_.treatAsRunOnce = p.treatAsRunOnce;
}
bool
LazyScript::hasUncompiledEnclosingScript() const
{
// It can happen that we created lazy scripts while compiling an enclosing
// script, but we errored out while compiling that script. When we iterate
// over lazy script in a compartment, we might see lazy scripts that never
// escaped to script and should be ignored.
//
// If the enclosing scope is a function with a null script or has a script
// without code, it was not successfully compiled.
if (!enclosingScope() || !enclosingScope()->is<FunctionScope>())
return false;
JSFunction* fun = enclosingScope()->as<FunctionScope>().canonicalFunction();
return !fun->hasScript() || fun->hasUncompiledScript() || !fun->nonLazyScript()->code();
}
void
JSScript::updateBaselineOrIonRaw(JSRuntime* maybeRuntime)
{
if (hasBaselineScript() && baseline->hasPendingIonBuilder()) {
MOZ_ASSERT(maybeRuntime);
MOZ_ASSERT(!isIonCompilingOffThread());
baselineOrIonRaw = maybeRuntime->jitRuntime()->lazyLinkStub()->raw();
baselineOrIonSkipArgCheck = maybeRuntime->jitRuntime()->lazyLinkStub()->raw();
} else 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 = nullptr;
baselineOrIonSkipArgCheck = nullptr;
}
}
bool
JSScript::hasLoops()
{
if (!hasTrynotes())
return false;
JSTryNote* tn = trynotes()->vector;
JSTryNote* tnlimit = tn + trynotes()->length;
for (; tn < tnlimit; tn++) {
if (tn->kind == JSTRY_FOR_IN || tn->kind == JSTRY_LOOP)
return true;
}
return false;
}
bool
JSScript::mayReadFrameArgsDirectly()
{
return argumentsHasVarBinding() || hasRest();
}
static inline void
LazyScriptHash(uint32_t lineno, uint32_t column, uint32_t begin, uint32_t end,
HashNumber hashes[3])
{
HashNumber hash = lineno;
hash = RotateLeft(hash, 4) ^ column;
hash = RotateLeft(hash, 4) ^ begin;
hash = RotateLeft(hash, 4) ^ end;
hashes[0] = hash;
hashes[1] = RotateLeft(hashes[0], 4) ^ begin;
hashes[2] = RotateLeft(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;
}
UncompressedSourceCache::AutoHoldEntry holder;
size_t scriptBegin = script->sourceStart();
size_t length = script->sourceEnd() - scriptBegin;
const char16_t* scriptChars = script->scriptSource()->chars(cx, holder, scriptBegin, length);
if (!scriptChars)
return false;
MOZ_ASSERT(scriptBegin == lazy->begin());
const char16_t* lazyChars = lazy->scriptSource()->chars(cx, holder, scriptBegin, length);
if (!lazyChars)
return false;
return !memcmp(scriptChars, lazyChars, length);
}
void
JSScript::AutoDelazify::holdScript(JS::HandleFunction fun)
{
if (fun) {
if (fun->compartment()->isSelfHosting) {
// The self-hosting compartment is shared across runtimes, so we
// can't use JSAutoCompartment: it could cause races. Functions in
// the self-hosting compartment will never be lazy, so we can safely
// assume we don't have to delazify.
script_ = fun->nonLazyScript();
} else {
JSAutoCompartment ac(cx_, fun);
script_ = fun->getOrCreateScript(cx_);
if (script_) {
oldDoNotRelazify_ = script_->doNotRelazify_;
script_->setDoNotRelazify(true);
}
}
}
}
void
JSScript::AutoDelazify::dropScript()
{
// Don't touch script_ if it's in the self-hosting compartment, see the
// comment in holdScript.
if (script_ && !script_->compartment()->isSelfHosting)
script_->setDoNotRelazify(oldDoNotRelazify_);
script_ = nullptr;
}
JS::ubi::Node::Size
JS::ubi::Concrete<JSScript>::size(mozilla::MallocSizeOf mallocSizeOf) const
{
Size size = Arena::thingSize(get().asTenured().getAllocKind());
size += get().sizeOfData(mallocSizeOf);
size += get().sizeOfTypeScript(mallocSizeOf);
size_t baselineSize = 0;
size_t baselineStubsSize = 0;
jit::AddSizeOfBaselineData(&get(), mallocSizeOf, &baselineSize, &baselineStubsSize);
size += baselineSize;
size += baselineStubsSize;
size += jit::SizeOfIonData(&get(), mallocSizeOf);
MOZ_ASSERT(size > 0);
return size;
}
const char*
JS::ubi::Concrete<JSScript>::scriptFilename() const
{
return get().filename();
}
JS::ubi::Node::Size
JS::ubi::Concrete<js::LazyScript>::size(mozilla::MallocSizeOf mallocSizeOf) const
{
Size size = js::gc::Arena::thingSize(get().asTenured().getAllocKind());
size += get().sizeOfExcludingThis(mallocSizeOf);
return size;
}
const char*
JS::ubi::Concrete<js::LazyScript>::scriptFilename() const
{
auto sourceObject = get().sourceObject();
if (!sourceObject)
return nullptr;
auto source = sourceObject->source();
if (!source)
return nullptr;
return source->filename();
}
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