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/*
* Copyright (C) 2008-2023, 2026 Apple Inc. All rights reserved.
* Copyright (C) 2008 Cameron Zwarich <cwzwarich@uwaterloo.ca>
* Copyright (C) 2012 Igalia, S.L.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "BytecodeGenerator.h"
#include "AbstractModuleRecord.h"
#include "BuiltinExecutables.h"
#include "BuiltinNames.h"
#include "BytecodeGeneratorBaseInlines.h"
#include "BytecodeGeneratorification.h"
#include "BytecodeUseDef.h"
#include "DefinePropertyAttributes.h"
#include "Interpreter.h"
#include "JSAsyncGenerator.h"
#include "JSBigInt.h"
#include "JSCInlines.h"
#include "JSCellButterfly.h"
#include "JSTemplateObjectDescriptor.h"
#include "Options.h"
#include "PrivateFieldPutKind.h"
#include "StrongInlines.h"
#include "SuperSampler.h"
#include "SymbolTableInlines.h"
#include "TopExceptionScope.h"
#include "UnlinkedCodeBlock.h"
#include "UnlinkedEvalCodeBlock.h"
#include "UnlinkedFunctionCodeBlock.h"
#include "UnlinkedMetadataTableInlines.h"
#include "UnlinkedModuleProgramCodeBlock.h"
#include "UnlinkedProgramCodeBlock.h"
#include "VMTrapsInlines.h"
#include "VariableEnvironmentInlines.h"
#include <wtf/BitVector.h>
#include <wtf/HashSet.h>
#include <wtf/StdLibExtras.h>
#include <wtf/TZoneMallocInlines.h>
#include <wtf/text/WTFString.h>
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
namespace JSC {
WTF_MAKE_TZONE_ALLOCATED_IMPL(BytecodeGenerator);
WTF_MAKE_TZONE_ALLOCATED_IMPL(ForInContext);
template<typename CallOp>
struct VarArgsOp;
template<>
struct VarArgsOp<OpCall> {
using type = OpCallVarargs;
};
template<>
struct VarArgsOp<OpCallIgnoreResult> {
using type = OpCallVarargs;
};
template<>
struct VarArgsOp<OpCallDirectEval> {
using type = OpCallVarargs;
};
template<>
struct VarArgsOp<OpTailCall> {
using type = OpTailCallVarargs;
};
template<>
struct VarArgsOp<OpConstruct> {
using type = OpConstructVarargs;
};
template<>
struct VarArgsOp<OpSuperConstruct> {
using type = OpSuperConstructVarargs;
};
template<>
void GenericLabel<JSGeneratorTraits>::setLocation(BytecodeGenerator& generator, unsigned location)
{
static_cast<JSC::BytecodeGenerator&>(generator).invalidateLoadedPrivateNames();
m_location = location;
for (auto offset : m_unresolvedJumps) {
auto instruction = generator.m_writer.ref(offset);
int - offset;
#define CASE(__op) \
case __op::opcodeID: \
instruction->cast<__op>()->setTargetLabel(BoundLabel(target), [&]() { \
generator.m_codeBlock->addOutOfLineJumpTarget(instruction.offset(), target); \
return BoundLabel(); \
}); \
break;
switch (instruction->opcodeID()) {
CASE(OpJmp)
CASE(OpJtrue)
CASE(OpJfalse)
CASE(OpJeqNull)
CASE(OpJneqNull)
CASE(OpJundefinedOrNull)
CASE(OpJnundefinedOrNull)
CASE(OpJeq)
CASE(OpJstricteq)
CASE(OpJneq)
CASE(OpJeqPtr)
CASE(OpJneqPtr)
CASE(OpJnstricteq)
CASE(OpJless)
CASE(OpJlesseq)
CASE(OpJgreater)
CASE(OpJgreatereq)
CASE(OpJnless)
CASE(OpJnlesseq)
CASE(OpJngreater)
CASE(OpJngreatereq)
CASE(OpJbelow)
CASE(OpJbeloweq)
CASE(OpIteratorCloseCheck)
default:
ASSERT_NOT_REACHED();
}
#undef CASE
}
}
void Variable::dump(PrintStream& out) const
{
out.print(
"{ident = ", m_ident,
", offset = ", m_offset,
", local = ", RawPointer(m_local),
", attributes = ", m_attributes,
", kind = ", m_kind,
", symbolTableConstantIndex = ", m_symbolTableConstantIndex,
", isLexicallyScoped = ", m_isLexicallyScoped, "}");
}
FinallyContext::FinallyContext(BytecodeGenerator& generator, Label& finallyLabel)
: m_outerContext(generator.m_currentFinallyContext)
, m_finallyLabel(&finallyLabel)
{
ASSERT(m_jumps.isEmpty());
m_completionRecord.typeRegister = generator.newTemporary();
m_completionRecord.valueRegister = generator.newTemporary();
generator.emitLoad(completionTypeRegister(), CompletionType::Normal);
generator.moveEmptyValue(completionValueRegister());
}
template<typename EmitBytecodeFunctor>
void BytecodeGenerator::asyncFuncParametersTryCatchWrap(NOESCAPE const EmitBytecodeFunctor& emitBytecode)
{
TryData* tryData = nullptr;
if (m_asyncFuncParametersTryCatchInfo) {
AsyncFuncParametersTryCatchInfo& info = m_asyncFuncParametersTryCatchInfo.value();
ASSERT(info.catchStartLabel && info.thrownValue);
Ref<Label> tryStartLabel = newEmittedLabel();
tryData = pushTry(tryStartLabel.get(), *info.catchStartLabel.get(), HandlerType::SynthesizedCatch);
}
emitBytecode();
if (m_asyncFuncParametersTryCatchInfo) {
AsyncFuncParametersTryCatchInfo& info = m_asyncFuncParametersTryCatchInfo.value();
Ref<Label> tryEndLabel = newEmittedLabel();
popTry(tryData, tryEndLabel.get());
emitOutOfLineCatchHandler(info.thrownValue.get(), nullptr, tryData);
}
}
ParserError BytecodeGenerator::generate(unsigned& size)
{
if (m_outOfMemoryDuringConstruction) [[unlikely]]
return ParserError(ParserError::OutOfMemory);
bool callingNonCallableConstructor = false;
switch (constructorKind()) {
case ConstructorKind::None:
break;
case ConstructorKind::Naked:
case ConstructorKind::Base:
case ConstructorKind::Extends:
callingNonCallableConstructor = !isConstructor();
break;
}
m_codeBlock->setThisRegister(m_thisRegister.virtualRegister());
emitLogShadowChickenPrologueIfNecessary();
if (!callingNonCallableConstructor) {
// If we have declared a variable named "arguments" and we are using arguments then we should
// perform that assignment now.
if (m_needToInitializeArguments)
initializeVariable(variable(propertyNames().arguments), m_argumentsRegister);
{
bool shouldHoistInEval = m_codeType == EvalCode && !m_ecmaMode.isStrict();
RefPtr<RegisterID> topLevelScope;
for (auto functionPair : m_functionsToInitialize) {
FunctionMetadataNode* metadata = functionPair.first;
FunctionVariableType functionType = functionPair.second;
if (functionType == NormalFunctionVariable) {
Variable var = variable(metadata->ident());
if (RegisterID* local = var.local())
emitNewFunction(local, metadata);
else {
RefPtr<RegisterID> temp = newTemporary();
emitNewFunction(temp.get(), metadata);
initializeVariable(var, temp.get());
}
} else if (functionType == TopLevelFunctionVariable) {
RefPtr<RegisterID> temp = newTemporary();
emitNewFunction(temp.get(), metadata);
if (!topLevelScope) {
// We know this will resolve to the top level scope or global object because our parser/global initialization code
// doesn't allow let/const/class variables to have the same names as functions.
// This is a top level function, and it's an error to ever create a top level function
// name that would resolve to a lexical variable. E.g:
// ```
// function f() {
// {
// let x;
// {
// //// error thrown here
// eval("function x(){}");
// }
// }
// }
// ```
// Therefore, we're guaranteed to have this resolve to a top level variable.
RefPtr<RegisterID> topLevelObjectScope = shouldHoistInEval
? emitResolveScopeForHoistingFuncDeclInEval(nullptr, metadata->ident())
: emitResolveScope(nullptr, Variable(metadata->ident()));
topLevelScope = newBlockScopeVariable();
move(topLevelScope.get(), topLevelObjectScope.get());
}
if (shouldHoistInEval)
emitPutToScopeDynamic(topLevelScope.get(), metadata->ident(), temp.get(), ThrowIfNotFound, InitializationMode::NotInitialization);
else
emitPutToScope(topLevelScope.get(), Variable(metadata->ident()), temp.get(), ThrowIfNotFound, InitializationMode::NotInitialization);
} else
RELEASE_ASSERT_NOT_REACHED();
}
}
m_scopeNode->emitBytecode(*this);
} else {
// At this point we would have emitted an unconditional throw followed by some nonsense that's
// just an artifact of how this generator is structured. That code never runs, but it confuses
// bytecode analyses because it constitutes an unterminated basic block. So, we terminate the
// basic block the strongest way possible.
emitUnreachable();
}
for (auto& handler : m_exceptionHandlersToEmit) {
Ref<Label> realCatchTarget = newLabel();
TryData* tryData = handler.tryData;
OpCatch::emit(this, handler.exceptionRegister, handler.thrownValueRegister);
realCatchTarget->setLocation(*this, m_lastInstruction.offset());
if (handler.completionTypeRegister.isValid()) {
RegisterID completionTypeRegister { handler.completionTypeRegister };
CompletionType completionType =
tryData->handlerType == HandlerType::Finally || tryData->handlerType == HandlerType::SynthesizedFinally
? CompletionType::Throw
: CompletionType::Normal;
emitLoad(&completionTypeRegister, completionType);
}
emitJump(tryData->target.get());
tryData->target = WTF::move(realCatchTarget);
}
if (m_asyncFuncParametersTryCatchInfo) {
AsyncFuncParametersTryCatchInfo& info = m_asyncFuncParametersTryCatchInfo.value();
ASSERT(info.catchStartLabel && info.thrownValue);
emitLabel(*info.catchStartLabel.get());
JSTextPosition divot(m_scopeNode->startOffset());
if (promiseRegister()) {
RefPtr<RegisterID> rejectPromise = moveLinkTimeConstant(nullptr, LinkTimeConstant::rejectPromiseWithFirstResolvingFunctionCallCheck);
CallArguments args(*this, nullptr, 2);
emitLoad(args.thisRegister(), jsUndefined());
move(args.argumentRegister(0), promiseRegister());
move(args.argumentRegister(1), info.thrownValue.get());
emitCallIgnoreResult(newTemporary(), rejectPromise.get(), NoExpectedFunction, args, divot, divot, divot, DebuggableCall::No);
emitReturn(promiseRegister());
} else {
// If we are not creating a promise yet, we can just do `return @newRejectedPromise(thrownValue)`.
RefPtr<RegisterID> newRejectedPromise = moveLinkTimeConstant(nullptr, LinkTimeConstant::newRejectedPromise);
CallArguments args(*this, nullptr, 1);
emitLoad(args.thisRegister(), jsUndefined());
move(args.argumentRegister(0), info.thrownValue.get());
RefPtr<RegisterID> result = newTemporary();
emitCall(result.get(), newRejectedPromise.get(), NoExpectedFunction, args, divot, divot, divot, DebuggableCall::No);
emitReturn(result.get());
}
}
m_staticPropertyAnalyzer.kill();
for (auto& range : m_tryRanges) {
int start = range.start->bind();
int end = range.end->bind();
// This will happen for empty try blocks and for some cases of finally blocks:
//
// try {
// try {
// } finally {
// return 42;
// // *HERE*
// }
// } finally {
// print("things");
// }
//
// The return will pop scopes to execute the outer finally block. But this includes
// popping the try context for the inner try. The try context is live in the fall-through
// part of the finally block not because we will emit a handler that overlaps the finally,
// but because we haven't yet had a chance to plant the catch target. Then when we finish
// emitting code for the outer finally block, we repush the try contex, this time with a
// new start index. But that means that the start index for the try range corresponding
// to the inner-finally-following-the-return (marked as "*HERE*" above) will be greater
// than the end index of the try block. This is harmless since end < start handlers will
// never get matched in our logic, but we do the runtime a favor and choose to not emit
// such handlers at all.
if (end <= start)
continue;
UnlinkedHandlerInfo info(static_cast<uint32_t>(start), static_cast<uint32_t>(end),
static_cast<uint32_t>(range.tryData->target->bind()), range.tryData->handlerType);
m_codeBlock->addExceptionHandler(info);
}
if (m_needsGeneratorification)
performGeneratorification(*this, m_codeBlock.get(), m_writer, m_generatorFrameSymbolTable.get(), m_generatorFrameSymbolTableIndex);
RELEASE_ASSERT(m_codeBlock->numCalleeLocals() < static_cast<unsigned>(FirstConstantRegisterIndex));
size = instructions().size();
if (!m_codeBlock->finalize(m_writer.finalize())) [[unlikely]]
return ParserError(ParserError::OutOfMemory);
// We limit total bytecode sequence size to int32_t so that we can use int32_t jump offsets.
// Also, this allows us to use one bit of bytecode for some flag, including "ignore-result-flag".
if (size > static_cast<unsigned>(INT32_MAX))
return ParserError(ParserError::OutOfMemory);
if (m_expressionTooDeep)
return ParserError(ParserError::OutOfMemory);
return ParserError(ParserError::ErrorNone);
}
BytecodeGenerator::BytecodeGenerator(VM& vm, ProgramNode* programNode, UnlinkedProgramCodeBlock* codeBlock, OptionSet<CodeGenerationMode> codeGenerationMode, const RefPtr<TDZEnvironmentLink>& parentScopeTDZVariables, const FixedVector<Identifier>*, const PrivateNameEnvironment*)
: BytecodeGeneratorBase(makeUnique<UnlinkedCodeBlockGenerator>(vm, codeBlock), CodeBlock::llintBaselineCalleeSaveSpaceAsVirtualRegisters())
, m_codeGenerationMode(codeGenerationMode)
, m_scopeNode(programNode)
, m_thisRegister(CallFrame::thisArgumentOffset())
, m_codeType(GlobalCode)
, m_vm(vm)
, m_usesExceptions(false)
, m_expressionTooDeep(false)
, m_isBuiltinFunction(false)
, m_usesSloppyEval(false)
, m_allowTailCallOptimization(false)
, m_allowCallIgnoreResultOptimization(m_defaultAllowCallIgnoreResultOptimization)
, m_needsToUpdateArrowFunctionContext(programNode->usesArrowFunction() || programNode->usesEval())
, m_ecmaMode(ECMAMode::fromBool(programNode->isStrictMode()))
{
ASSERT_UNUSED(parentScopeTDZVariables, !parentScopeTDZVariables);
m_codeBlock->setNumParameters(1); // Allocate space for "this"
emitEnter();
allocateScope();
const FunctionStack& functionStack = programNode->functionStack();
for (auto* function : functionStack)
m_functionsToInitialize.append(std::make_pair(function, TopLevelFunctionVariable));
if (Options::validateBytecode()) {
for (auto& entry : programNode->varDeclarations())
RELEASE_ASSERT(entry.value.isVar());
}
codeBlock->setVariableDeclarations(programNode->varDeclarations());
codeBlock->setLexicalDeclarations(programNode->lexicalVariables());
// Even though this program may have lexical variables that go under TDZ, when linking the get_from_scope/put_to_scope
// operations we emit we will have ResolveTypes that implictly do TDZ checks. Therefore, we don't need
// additional TDZ checks on top of those. This is why we can omit pushing programNode->lexicalVariables()
// to the TDZ stack.
if (needsToUpdateArrowFunctionContext()) {
initializeArrowFunctionContextScopeIfNeeded();
emitPutThisToArrowFunctionContextScope();
}
}
BytecodeGenerator::BytecodeGenerator(VM& vm, FunctionNode* functionNode, UnlinkedFunctionCodeBlock* codeBlock, OptionSet<CodeGenerationMode> codeGenerationMode, const RefPtr<TDZEnvironmentLink>& parentScopeTDZVariables, const FixedVector<Identifier>* generatorOrAsyncWrapperFunctionParameterNames, const PrivateNameEnvironment* parentPrivateNameEnvironment)
: BytecodeGeneratorBase(makeUnique<UnlinkedCodeBlockGenerator>(vm, codeBlock), CodeBlock::llintBaselineCalleeSaveSpaceAsVirtualRegisters())
, m_codeGenerationMode(codeGenerationMode)
, m_scopeNode(functionNode)
, m_codeType(FunctionCode)
, m_vm(vm)
, m_defaultAllowCallIgnoreResultOptimization(true)
// FIXME: This should be a flag
, m_usesExceptions(false)
, m_expressionTooDeep(false)
, m_isBuiltinFunction(codeBlock->isBuiltinFunction())
, m_isBuiltinDefaultClassConstructor(codeBlock->isBuiltinDefaultClassConstructor())
, m_usesSloppyEval(functionNode->usesEval() && !functionNode->isStrictMode())
// FIXME: We should be able to have tail call elimination with the profiler
// enabled. This is currently not possible because the profiler expects
// op_will_call / op_did_call pairs before and after a call, which are not
// compatible with tail calls (we have no way of emitting op_did_call).
// https://bugs.webkit.org/show_bug.cgi?id=148819
//
// Note that we intentionally enable tail call for naked constructors since it does not have special code for "return".
//
// Generator, async function, and async generator bodies hold no tail positions at all
// (IsInTailPosition steps 4 to 7): their "return" is not a plain return. An async generator
// awaits the returned value, and a tail call would jump over that await.
, m_allowTailCallOptimization(Options::useTailCalls() && !isConstructor() && constructorKind() == ConstructorKind::None && functionNode->isStrictMode() && !isGeneratorOrAsyncFunctionBodyParseMode(parseMode()))
, m_allowCallIgnoreResultOptimization(m_defaultAllowCallIgnoreResultOptimization)
, m_needsToUpdateArrowFunctionContext(functionNode->usesArrowFunction() || functionNode->usesEval())
, m_ecmaMode(ECMAMode::fromBool(functionNode->isStrictMode()))
, m_derivedContextType(codeBlock->derivedContextType())
{
ECMAMode ecmaMode = m_ecmaMode;
pushPrivateAccessNames(parentPrivateNameEnvironment);
SymbolTable* functionSymbolTable = SymbolTable::create(m_vm);
functionSymbolTable->setUsesSloppyEval(m_usesSloppyEval);
int symbolTableConstantIndex = 0;
m_cachedParentTDZ = parentScopeTDZVariables;
m_generatorOrAsyncWrapperFunctionParameterNames = generatorOrAsyncWrapperFunctionParameterNames;
FunctionParameters& parameters = *functionNode->parameters();
// http://www.ecma-international.org/ecma-262/6.0/index.html#sec-functiondeclarationinstantiation
// This implements IsSimpleParameterList in the Ecma 2015 spec.
// If IsSimpleParameterList is false, we will create a strict-mode like arguments object.
// IsSimpleParameterList is false if the argument list contains any default parameter values,
// a rest parameter, or any destructuring patterns.
// If we do have default parameters, destructuring parameters, or a rest parameter, our parameters will be allocated in a different scope.
bool isSimpleParameterList = parameters.isSimpleParameterList();
SourceParseMode parseMode = codeBlock->parseMode();
bool containsArrowOrEvalButNotInArrowBlock = ((functionNode->usesArrowFunction() && functionNode->doAnyInnerArrowFunctionsUseAnyFeature()) || usesEval()) && !m_codeBlock->isArrowFunction();
bool shouldCaptureSomeOfTheThings = shouldEmitDebugHooks() || functionNode->needsActivation() || containsArrowOrEvalButNotInArrowBlock;
bool shouldCaptureAllOfTheThings = shouldEmitDebugHooks() || usesEval();
m_needsArguments = ([&] () {
if (parseMode != SourceParseMode::ClassFieldInitializerMode) {
if (!codeBlock->isArrowFunction()) {
if (functionNode->usesArrowFunction() && isArgumentsUsedInInnerArrowFunction())
return true;
if (functionNode->usesArguments())
return true;
if (shouldEmitDebugHooks())
return true;
}
if (usesEval())
return true;
}
return false;
})();
if (isGeneratorOrAsyncFunctionBodyParseMode(parseMode)) {
m_needsGeneratorification = true;
// Generator and AsyncFunction never provides "arguments". "arguments" reference will be resolved in an upper generator function scope.
m_needsArguments = false;
} else if (isGeneratorOrAsyncFunctionWrapperParseMode(parseMode)) {
// Generator does not provide "arguments". Instead, wrapping GeneratorFunction provides "arguments".
// This is because arguments of a generator should be evaluated before starting it.
// To workaround it, we evaluate these arguments as arguments of a wrapping generator function, and reference it from a generator.
//
// function *gen(a, b = hello())
// {
// return {
// @generatorNext: function (@generator, @generatorState, @generatorValue, @generatorResumeMode, @generatorFrame)
// {
// arguments; // This `arguments` should reference to the gen's arguments.
// ...
// }
// }
// }
//
// For async functions without await, the body is inlined directly - no body function exists.
// So we don't need to capture parameters for the body function to access them.
if (!(isAsyncFunctionWrapperParseMode(parseMode) && functionNode->isAsyncFunctionWithoutAwait())) {
if (m_needsArguments)
shouldCaptureSomeOfTheThings = true;
if (parameters.size()) {
shouldCaptureSomeOfTheThings = true;
shouldCaptureAllOfTheThings = true;
}
}
}
if (shouldCaptureAllOfTheThings)
functionNode->varDeclarations().markAllVariablesAsCaptured();
auto captures = [&] (UniquedStringImpl* uid) -> bool {
if (!shouldCaptureSomeOfTheThings)
return false;
if (m_needsArguments && uid == propertyNames().arguments.impl()) {
// An async function with no await is inlined. Any other generator or async wrapper
// has a separate body that resolves this frame's arguments.
bool separateBodyResolvesArguments = isGeneratorOrAsyncFunctionWrapperParseMode(parseMode)
&& !(isAsyncFunctionWrapperParseMode(parseMode) && functionNode->isAsyncFunctionWithoutAwait());
return separateBodyResolvesArguments
|| (functionNode->features() & WithFeature)
|| (functionNode->usesArrowFunction() && isArgumentsUsedInInnerArrowFunction())
|| functionNode->captures(uid);
}
return functionNode->captures(uid);
};
auto varKind = [&] (UniquedStringImpl* uid) -> VarKind {
return captures(uid) ? VarKind::Scope : VarKind::Stack;
};
m_calleeRegister.setIndex(CallFrameSlot::callee);
initializeParameters(parameters);
ASSERT(!(isSimpleParameterList && m_restParameter));
emitEnter();
if (isGeneratorOrAsyncFunctionBodyParseMode(parseMode))
m_generatorRegister = &m_parameters[static_cast<unsigned>(JSGenerator::Argument::Generator)];
allocateScope();
switch (constructorKind()) {
case ConstructorKind::None:
break;
case ConstructorKind::Naked:
if (!isConstructor()) {
String constructorName = functionNode->ident().string();
if (!constructorName || constructorName.isEmpty())
emitThrowTypeError("Cannot call a constructor without |new|"_s);
else {
auto errorMessageStr = tryMakeString("Cannot call a constructor "_s, constructorName, " without |new|"_s);
if (!errorMessageStr)
emitThrowTypeError("Cannot call a constructor without |new|"_s);
else
emitThrowTypeError(Identifier::fromString(m_vm, errorMessageStr));
}
return;
}
break;
case ConstructorKind::Base:
case ConstructorKind::Extends:
if (!isConstructor()) {
String constructorName = functionNode->ident().string();
if (!constructorName || constructorName.isEmpty())
emitThrowTypeError("Cannot call a class constructor without |new|"_s);
else {
auto errorMessageStr = tryMakeString("Cannot call a class constructor "_s, constructorName, " without |new|"_s);
if (!errorMessageStr)
emitThrowTypeError("Cannot call a class constructor without |new|"_s);
else
emitThrowTypeError(Identifier::fromString(m_vm, errorMessageStr));
}
return;
}
break;
}
if (functionNameIsInScope(functionNode->ident(), functionNode->functionMode())) {
ASSERT(parseMode != SourceParseMode::GeneratorBodyMode);
ASSERT(!isAsyncFunctionBodyParseMode(parseMode));
bool isDynamicScope = functionNameScopeIsDynamic(usesEval(), ecmaMode.isStrict());
bool isFunctionNameCaptured = captures(functionNode->ident().impl());
bool markAsCaptured = isDynamicScope || isFunctionNameCaptured;
emitPushFunctionNameScope(functionNode->ident(), &m_calleeRegister, markAsCaptured);
}
if (shouldCaptureSomeOfTheThings)
m_lexicalEnvironmentRegister = addVar();
if (isGeneratorOrAsyncFunctionBodyParseMode(parseMode) || shouldCaptureSomeOfTheThings || shouldEmitTypeProfilerHooks())
symbolTableConstantIndex = addConstantValue(functionSymbolTable)->index();
// We can allocate the "var" environment if we don't have default parameter expressions. If we have
// default parameter expressions, we have to hold off on allocating the "var" environment because
// the parent scope of the "var" environment is the parameter environment.
if (isSimpleParameterList)
initializeVarLexicalEnvironment(symbolTableConstantIndex, functionSymbolTable, shouldCaptureSomeOfTheThings);
// Need to know what our functions are called. Parameters have some goofy behaviors when it
// comes to functions of the same name.
for (FunctionMetadataNode* function : functionNode->functionStack())
m_functions.add(function->ident().impl());
if (m_needsArguments) {
// Create the arguments object now. We may put the arguments object into the activation if
// it is captured. Either way, we create two arguments object variables: one is our
// private variable that is immutable, and another that is the user-visible variable. The
// immutable one is only used here, or during formal parameter resolutions if we opt for
// DirectArguments.
m_argumentsRegister = addVar();
m_argumentsRegister->ref();
}
if (m_needsArguments && !ecmaMode.isStrict() && isSimpleParameterList) {
// If we captured any formal parameter by name, then we use ScopedArguments. Otherwise we
// use DirectArguments. With ScopedArguments, we lift all of our arguments into the
// activation.
bool capturesAnyParameterByName = false;
if (functionNode->hasCapturedVariables()) {
for (size_t i = 0; i < parameters.size(); ++i) {
auto pattern = parameters.at(i).first;
ASSERT(pattern->isBindingNode());
const Identifier& ident = static_cast<const BindingNode*>(pattern)->boundProperty();
if (captures(ident.impl())) {
capturesAnyParameterByName = true;
break;
}
}
}
if (capturesAnyParameterByName) {
ASSERT(m_lexicalEnvironmentRegister);
bool success = functionSymbolTable->trySetArgumentsLength(vm, parameters.size());
if (!success) [[unlikely]] {
m_outOfMemoryDuringConstruction = true;
return;
}
// For each parameter, we have two possibilities:
// Either it's a binding node with no function overlap, in which case it gets a name
// in the symbol table - or it just gets space reserved in the symbol table. Either
// way we lift the value into the scope.
for (unsigned i = 0; i < parameters.size(); ++i) {
ScopeOffset offset = functionSymbolTable->takeNextScopeOffset(NoLockingNecessary);
bool success = functionSymbolTable->trySetArgumentOffset(vm, i, offset);
if (!success) [[unlikely]] {
m_outOfMemoryDuringConstruction = true;
return;
}
unsigned varOrAnonymous = UINT_MAX;
if (UniquedStringImpl* name = visibleNameForParameter(parameters.at(i).first)) {
VarOffset varOffset(offset);
SymbolTableEntry entry(varOffset);
functionSymbolTable->set(NoLockingNecessary, name, WTF::move(entry));
IGNORE_GCC_WARNINGS_BEGIN("dangling-reference")
const Identifier& ident =
static_cast<const BindingNode*>(parameters.at(i).first)->boundProperty();
IGNORE_GCC_WARNINGS_END
varOrAnonymous = addConstant(ident);
}
OpPutToScope::emit(this, m_lexicalEnvironmentRegister, varOrAnonymous, virtualRegisterForArgumentIncludingThis(1 + i), GetPutInfo(ThrowIfNotFound, ResolvedClosureVar, InitializationMode::ScopedArgumentInitialization, ecmaMode), SymbolTableOrScopeDepth::symbolTable(VirtualRegister { symbolTableConstantIndex }), offset.offset());
}
// This creates a scoped arguments object and copies the overflow arguments into the
// scope. It's the equivalent of calling ScopedArguments::createByCopying().
OpCreateScopedArguments::emit(this, m_argumentsRegister, m_lexicalEnvironmentRegister);
} else {
// We're going to put all parameters into the DirectArguments object. First ensure
// that the symbol table knows that this is happening.
for (unsigned i = 0; i < parameters.size(); ++i) {
if (UniquedStringImpl* name = visibleNameForParameter(parameters.at(i).first))
functionSymbolTable->set(NoLockingNecessary, name, SymbolTableEntry(VarOffset(DirectArgumentsOffset(i))));
}
OpCreateDirectArguments::emit(this, m_argumentsRegister);
}
} else if (isSimpleParameterList) {
// Create the formal parameters the normal way. Any of them could be captured, or not. If
// captured, lift them into the scope. We cannot do this if we have default parameter expressions
// because when default parameter expressions exist, they belong in their own lexical environment
// separate from the "var" lexical environment.
for (unsigned i = 0; i < parameters.size(); ++i) {
UniquedStringImpl* name = visibleNameForParameter(parameters.at(i).first);
if (!name)
continue;
if (!captures(name)) {
// This is the easy case - just tell the symbol table about the argument. It will
// be accessed directly.
functionSymbolTable->set(NoLockingNecessary, name, SymbolTableEntry(VarOffset(virtualRegisterForArgumentIncludingThis(1 + i))));
continue;
}
ScopeOffset offset = functionSymbolTable->takeNextScopeOffset(NoLockingNecessary);
functionSymbolTable->set(NoLockingNecessary, name, SymbolTableEntry(VarOffset(offset)));
IGNORE_GCC_WARNINGS_BEGIN("dangling-reference")
const Identifier& ident =
static_cast<const BindingNode*>(parameters.at(i).first)->boundProperty();
IGNORE_GCC_WARNINGS_END
OpPutToScope::emit(this, m_lexicalEnvironmentRegister, addConstant(ident), virtualRegisterForArgumentIncludingThis(1 + i), GetPutInfo(ThrowIfNotFound, ResolvedClosureVar, InitializationMode::NotInitialization, ecmaMode), SymbolTableOrScopeDepth::symbolTable(VirtualRegister { symbolTableConstantIndex }), offset.offset());
}
}
if (m_needsArguments && (ecmaMode.isStrict() || !isSimpleParameterList)) {
// Allocate a cloned arguments object.
OpCreateClonedArguments::emit(this, m_argumentsRegister);
}
// There are some variables that need to be preinitialized to something other than Undefined:
//
// - "arguments": unless it's used as a function or parameter, this should refer to the
// arguments object.
//
// - functions: these always override everything else.
//
// The most logical way to do all of this is to initialize none of the variables until now,
// and then initialize them in BytecodeGenerator::generate() in such an order that the rules
// for how these things override each other end up holding. We would initialize "arguments" first,
// then all arguments, then the functions.
//
// But some arguments are already initialized by default, since if they aren't captured and we
// don't have "arguments" then we just point the symbol table at the stack slot of those
// arguments. We end up initializing the rest of the arguments that have an uncomplicated
// binding (i.e. don't involve destructuring) above when figuring out how to lay them out,
// because that's just the simplest thing. This means that when we initialize them, we have to
// watch out for the things that override arguments (namely, functions).
// This is our final act of weirdness. "arguments" is overridden by everything except the
// callee. We add it to the symbol table if it's not already there and it's not an argument.
bool shouldCreateArgumentsVariableInParameterScope = false;
if (m_needsArguments) {
// If "arguments" is overridden by a function or destructuring parameter name, then it's
// OK for us to call createVariable() because it won't change anything. It's also OK for
// us to them tell BytecodeGenerator::generate() to write to it because it will do so
// before it initializes functions and destructuring parameters. But if "arguments" is
// overridden by a "simple" function parameter, then we have to bail: createVariable()
// would assert and BytecodeGenerator::generate() would write the "arguments" after the
// argument value had already been properly initialized.
bool haveParameterNamedArguments = false;
for (unsigned i = 0; i < parameters.size(); ++i) {
UniquedStringImpl* name = visibleNameForParameter(parameters.at(i).first);
if (name == propertyNames().arguments.impl()) {
haveParameterNamedArguments = true;
break;
}
}
bool shouldCreateArgumensVariable = !haveParameterNamedArguments
&& !SourceParseModeSet(SourceParseMode::ArrowFunctionMode, SourceParseMode::AsyncArrowFunctionMode, SourceParseMode::ClassFieldInitializerMode).contains(m_codeBlock->parseMode());
shouldCreateArgumentsVariableInParameterScope = shouldCreateArgumensVariable && !isSimpleParameterList;
// Do not create arguments variable in case of Arrow function. Value will be loaded from parent scope
if (shouldCreateArgumensVariable && !shouldCreateArgumentsVariableInParameterScope) {
createVariable(
propertyNames().arguments, varKind(propertyNames().arguments.impl()), functionSymbolTable);
m_needToInitializeArguments = true;
}
}
for (FunctionMetadataNode* function : functionNode->functionStack()) {
const Identifier& ident = function->ident();
createVariable(ident, varKind(ident.impl()), functionSymbolTable);
m_functionsToInitialize.append(std::make_pair(function, NormalFunctionVariable));
}
for (auto& entry : functionNode->varDeclarations()) {
ASSERT(!entry.value.isLet() && !entry.value.isConst());
if (!entry.value.isVar()) // This is either a parameter or callee.
continue;
if (shouldCreateArgumentsVariableInParameterScope && entry.key.get() == propertyNames().arguments.impl())
continue;
if (generatorOrAsyncWrapperFunctionParameterNames && generatorOrAsyncWrapperFunctionParameterNames->contains(entry.key.get()))
continue;
createVariable(Identifier::fromUid(m_vm, entry.key.get()), varKind(entry.key.get()), functionSymbolTable, IgnoreExisting);
}
if (functionNode->needsNewTargetRegisterForThisScope() || isNewTargetUsedInInnerArrowFunction() || usesEval())
m_newTargetRegister = addVar();
auto shouldEmitToThis = [&] {
if (functionNode->usesThis() || usesEval() || m_scopeNode->doAnyInnerArrowFunctionsUseThis() || m_scopeNode->doAnyInnerArrowFunctionsUseEval())
return true;
if ((functionNode->usesSuperProperty() || m_scopeNode->doAnyInnerArrowFunctionsUseSuperProperty()) && !ecmaMode.isStrict()) {
// We must emit to_this when we're not in strict mode because we
// will convert |this| to an object, and that object may be passed
// to a strict function as |this|. This is observable because that
// strict function's to_this will just return the object.
//
// We don't need to emit this for strict-mode code because
// strict-mode code may call another strict function, which will
// to_this if it directly uses this; this is OK, because we defer
// to_this until |this| is used directly. Strict-mode code might
// also call a sloppy mode function, and that will to_this, which
// will defer the conversion, again, until necessary.
return true;
}
return false;
};
switch (parseMode) {
case SourceParseMode::GeneratorWrapperFunctionMode:
case SourceParseMode::GeneratorWrapperMethodMode:
case SourceParseMode::AsyncGeneratorWrapperMethodMode:
case SourceParseMode::AsyncGeneratorWrapperFunctionMode: {
m_generatorRegister = addVar();
// FIXME: Emit to_this only when Generator uses it.
// https://bugs.webkit.org/show_bug.cgi?id=151586
emitToThis();
break;
}
case SourceParseMode::AsyncArrowFunctionMode:
case SourceParseMode::AsyncMethodMode:
case SourceParseMode::AsyncFunctionMode: {
ASSERT(!isConstructor());
ASSERT(constructorKind() == ConstructorKind::None);
bool isAsyncFunctionWithoutAwait = m_scopeNode->isAsyncFunctionWithoutAwait();
// Check if this async function body doesn't use await.
// If so, we can skip generator creation entirely.
if (!isAsyncFunctionWithoutAwait) {
m_generatorRegister = addVar();
m_promiseRegister = addVar();
}
bool willEmitToThis = false;
if (parseMode != SourceParseMode::AsyncArrowFunctionMode) {
// FIXME: Emit to_this only when AsyncFunctionBody uses it.
// https://bugs.webkit.org/show_bug.cgi?id=151586
if (isAsyncFunctionWithoutAwait)
willEmitToThis = shouldEmitToThis();
else
willEmitToThis = true;
}
if (willEmitToThis)
emitToThis();
if (!isAsyncFunctionWithoutAwait) {
emitNewPromise(promiseRegister());
emitNewAsyncFunctionGenerator(m_generatorRegister);
emitPutInternalField(generatorRegister(), static_cast<unsigned>(JSAsyncFunctionGenerator::Field::Context), promiseRegister());
}
break;
}
case SourceParseMode::AsyncGeneratorBodyMode:
case SourceParseMode::AsyncFunctionBodyMode:
case SourceParseMode::AsyncArrowFunctionBodyMode:
case SourceParseMode::GeneratorBodyMode: {
// |this| is already filled correctly before here.
if (m_newTargetRegister)
emitLoad(m_newTargetRegister, jsUndefined());
break;
}
case SourceParseMode::ArrowFunctionMode:
break;
default: {
if (isConstructor()) {
if (m_newTargetRegister)
move(m_newTargetRegister, &m_thisRegister);
switch (constructorKind()) {
case ConstructorKind::Naked:
// Naked constructor not create |this| automatically.
break;
case ConstructorKind::None:
case ConstructorKind::Base:
emitCreateThis(&m_thisRegister);
if (privateBrandRequirement() == PrivateBrandRequirement::Needed)
emitInstallPrivateBrand(&m_thisRegister);
emitInstanceFieldInitializationIfNeeded(&m_thisRegister, &m_calleeRegister, m_scopeNode->position(), m_scopeNode->position(), m_scopeNode->position());
break;
case ConstructorKind::Extends:
moveEmptyValue(&m_thisRegister);
break;
}
} else {
switch (constructorKind()) {
case ConstructorKind::None: {
if (shouldEmitToThis())
emitToThis();
break;
}
case ConstructorKind::Naked:
case ConstructorKind::Base:
case ConstructorKind::Extends:
RELEASE_ASSERT_NOT_REACHED();
break;
}
}
break;
}
}
// We need load |super| & |this| for arrow function before initializeDefaultParameterValuesAndSetupFunctionScopeStack
// if we have default parameter expression. Because |super| & |this| values can be used there
if ((SourceParseModeSet(SourceParseMode::ArrowFunctionMode, SourceParseMode::AsyncArrowFunctionMode).contains(parseMode) && !isSimpleParameterList) || parseMode == SourceParseMode::AsyncArrowFunctionBodyMode) {
if (functionNode->usesThis() || functionNode->usesSuperProperty())
emitLoadThisFromArrowFunctionLexicalEnvironment();
if (m_scopeNode->needsNewTargetRegisterForThisScope())
emitLoadNewTargetFromArrowFunctionLexicalEnvironment();
}
if (needsToUpdateArrowFunctionContext() && !codeBlock->isArrowFunction()) {
bool canReuseLexicalEnvironment = isSimpleParameterList;
initializeArrowFunctionContextScopeIfNeeded(functionSymbolTable, canReuseLexicalEnvironment);
emitPutThisToArrowFunctionContextScope();
emitPutNewTargetToArrowFunctionContextScope();
emitPutDerivedConstructorToArrowFunctionContextScope();
}
if (isAsyncFunctionWrapperParseMode(parseMode) && !isSimpleParameterList)
m_asyncFuncParametersTryCatchInfo = { newLabel(), newTemporary() };
asyncFuncParametersTryCatchWrap([&]() {
// All "addVar()"s needs to happen before "initializeDefaultParameterValuesAndSetupFunctionScopeStack()" is called
// because a function's default parameter ExpressionNodes will use temporary registers.
initializeDefaultParameterValuesAndSetupFunctionScopeStack(parameters, isSimpleParameterList, functionNode, functionSymbolTable, symbolTableConstantIndex, captures, shouldCreateArgumentsVariableInParameterScope);
});
// If we don't have default parameter expression, then loading |this| inside an arrow function must be done
// after initializeDefaultParameterValuesAndSetupFunctionScopeStack() because that function sets up the
// SymbolTable stack and emitLoadThisFromArrowFunctionLexicalEnvironment() consults the SymbolTable stack
if (SourceParseModeSet(SourceParseMode::ArrowFunctionMode, SourceParseMode::AsyncArrowFunctionMode).contains(parseMode) && isSimpleParameterList) {
if (functionNode->usesThis() || functionNode->usesSuperProperty())
emitLoadThisFromArrowFunctionLexicalEnvironment();
if (m_scopeNode->needsNewTargetRegisterForThisScope())
emitLoadNewTargetFromArrowFunctionLexicalEnvironment();
}
if (isGeneratorWrapperParseMode(parseMode))
emitCreateGenerator(m_generatorRegister, &m_calleeRegister);
else if (isAsyncGeneratorWrapperParseMode(parseMode))
emitCreateAsyncGenerator(m_generatorRegister, &m_calleeRegister);
// Set up the lexical environment scope as the generator frame. We store the saved and resumed generator registers into this scope with the symbol keys.
// Since they are symbol keyed, these variables cannot be reached from the usual code.
if (isGeneratorOrAsyncFunctionBodyParseMode(parseMode)) {
m_generatorFrameSymbolTable.set(m_vm, functionSymbolTable);
m_generatorFrameSymbolTableIndex = symbolTableConstantIndex;
if (m_lexicalEnvironmentRegister)
move(generatorFrameRegister(), m_lexicalEnvironmentRegister);
else {
// It would be possible that generator does not need to suspend and resume any registers.
// In this case, we would like to avoid creating a lexical environment as much as possible.
// op_create_generator_frame_environment is a marker, which is similar to op_yield.
// Generatorification inserts lexical environment creation if necessary. Otherwise, we convert it to op_mov frame, `undefined`.
OpCreateGeneratorFrameEnvironment::emit(this, generatorFrameRegister(), scopeRegister(), VirtualRegister { symbolTableConstantIndex }, addConstantValue(jsUndefined()));
}
static_assert(static_cast<unsigned>(JSGenerator::Field::Frame) == static_cast<unsigned>(JSAsyncGenerator::Field::Frame));
emitPutInternalField(generatorRegister(), static_cast<unsigned>(JSGenerator::Field::Frame), generatorFrameRegister());
}
unsigned privateNameRegisterCount = std::min(functionNode->usedPrivateNameCount(), maxPrivateNameRegisters);
for (unsigned i = 0; i < privateNameRegisterCount; ++i)
m_privateNameRegisters.append(newBlockScopeVariable());
bool shouldInitializeBlockScopedFunctions = false; // We generate top-level function declarations in ::generate().