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chromium / v8 / v8 / 585b39f53a5eb3f4d931c505f3a1bc4288be60ce / . / src / parsing / parser.cc
blob: 0221bb95bd9dd04934ad03e7becfa69bf37c2fb9 [file] [log] [blame]
// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/parsing/parser.h"
#include <algorithm>
#include <memory>
#include "src/api.h"
#include "src/ast/ast-function-literal-id-reindexer.h"
#include "src/ast/ast-traversal-visitor.h"
#include "src/ast/ast.h"
#include "src/bailout-reason.h"
#include "src/base/platform/platform.h"
#include "src/char-predicates-inl.h"
#include "src/compiler-dispatcher/compiler-dispatcher.h"
#include "src/log.h"
#include "src/messages.h"
#include "src/objects-inl.h"
#include "src/parsing/duplicate-finder.h"
#include "src/parsing/expression-scope-reparenter.h"
#include "src/parsing/parse-info.h"
#include "src/parsing/rewriter.h"
#include "src/runtime/runtime.h"
#include "src/string-stream.h"
#include "src/tracing/trace-event.h"
namespace v8 {
namespace internal {
ScriptData::ScriptData(const byte* data, int length)
: owns_data_(false), rejected_(false), data_(data), length_(length) {
if (!IsAligned(reinterpret_cast<intptr_t>(data), kPointerAlignment)) {
byte* copy = NewArray<byte>(length);
DCHECK(IsAligned(reinterpret_cast<intptr_t>(copy), kPointerAlignment));
CopyBytes(copy, data, length);
data_ = copy;
AcquireDataOwnership();
}
}
FunctionEntry ParseData::GetFunctionEntry(int start) {
// The current pre-data entry must be a FunctionEntry with the given
// start position.
if ((function_index_ + FunctionEntry::kSize <= Length()) &&
(static_cast<int>(Data()[function_index_]) == start)) {
int index = function_index_;
function_index_ += FunctionEntry::kSize;
Vector<unsigned> subvector(&(Data()[index]), FunctionEntry::kSize);
return FunctionEntry(subvector);
}
return FunctionEntry();
}
int ParseData::FunctionCount() {
int functions_size = FunctionsSize();
if (functions_size < 0) return 0;
if (functions_size % FunctionEntry::kSize != 0) return 0;
return functions_size / FunctionEntry::kSize;
}
bool ParseData::IsSane() {
if (!IsAligned(script_data_->length(), sizeof(unsigned))) return false;
// Check that the header data is valid and doesn't specify
// point to positions outside the store.
int data_length = Length();
if (data_length < PreparseDataConstants::kHeaderSize) return false;
if (Magic() != PreparseDataConstants::kMagicNumber) return false;
if (Version() != PreparseDataConstants::kCurrentVersion) return false;
// Check that the space allocated for function entries is sane.
int functions_size = FunctionsSize();
if (functions_size < 0) return false;
if (functions_size % FunctionEntry::kSize != 0) return false;
// Check that the total size has room for header and function entries.
int minimum_size =
PreparseDataConstants::kHeaderSize + functions_size;
if (data_length < minimum_size) return false;
return true;
}
void ParseData::Initialize() {
// Prepares state for use.
int data_length = Length();
if (data_length >= PreparseDataConstants::kHeaderSize) {
function_index_ = PreparseDataConstants::kHeaderSize;
}
}
unsigned ParseData::Magic() {
return Data()[PreparseDataConstants::kMagicOffset];
}
unsigned ParseData::Version() {
return Data()[PreparseDataConstants::kVersionOffset];
}
int ParseData::FunctionsSize() {
return static_cast<int>(Data()[PreparseDataConstants::kFunctionsSizeOffset]);
}
// Helper for putting parts of the parse results into a temporary zone when
// parsing inner function bodies.
class DiscardableZoneScope {
public:
DiscardableZoneScope(Parser* parser, Zone* temp_zone, bool use_temp_zone)
: fni_(parser->ast_value_factory_, temp_zone),
parser_(parser),
prev_fni_(parser->fni_),
prev_zone_(parser->zone_),
prev_allow_lazy_(parser->allow_lazy_),
prev_temp_zoned_(parser->temp_zoned_) {
if (use_temp_zone) {
DCHECK(!parser_->temp_zoned_);
parser_->allow_lazy_ = false;
parser_->temp_zoned_ = true;
parser_->fni_ = &fni_;
parser_->zone_ = temp_zone;
parser_->factory()->set_zone(temp_zone);
if (parser_->reusable_preparser_ != nullptr) {
parser_->reusable_preparser_->zone_ = temp_zone;
parser_->reusable_preparser_->factory()->set_zone(temp_zone);
}
}
}
void Reset() {
parser_->fni_ = prev_fni_;
parser_->zone_ = prev_zone_;
parser_->factory()->set_zone(prev_zone_);
parser_->allow_lazy_ = prev_allow_lazy_;
parser_->temp_zoned_ = prev_temp_zoned_;
if (parser_->reusable_preparser_ != nullptr) {
parser_->reusable_preparser_->zone_ = prev_zone_;
parser_->reusable_preparser_->factory()->set_zone(prev_zone_);
}
}
~DiscardableZoneScope() { Reset(); }
private:
FuncNameInferrer fni_;
Parser* parser_;
FuncNameInferrer* prev_fni_;
Zone* prev_zone_;
bool prev_allow_lazy_;
bool prev_temp_zoned_;
DISALLOW_COPY_AND_ASSIGN(DiscardableZoneScope);
};
void Parser::SetCachedData(ParseInfo* info) {
DCHECK_NULL(cached_parse_data_);
if (consume_cached_parse_data()) {
if (allow_lazy_) {
cached_parse_data_ = ParseData::FromCachedData(*info->cached_data());
if (cached_parse_data_ != nullptr) return;
}
compile_options_ = ScriptCompiler::kNoCompileOptions;
}
}
FunctionLiteral* Parser::DefaultConstructor(const AstRawString* name,
bool call_super, int pos,
int end_pos) {
int expected_property_count = -1;
const int parameter_count = 0;
FunctionKind kind = call_super ? FunctionKind::kDefaultDerivedConstructor
: FunctionKind::kDefaultBaseConstructor;
DeclarationScope* function_scope = NewFunctionScope(kind);
SetLanguageMode(function_scope, LanguageMode::kStrict);
// Set start and end position to the same value
function_scope->set_start_position(pos);
function_scope->set_end_position(pos);
ZoneList<Statement*>* body = nullptr;
{
FunctionState function_state(&function_state_, &scope_, function_scope);
body = new (zone()) ZoneList<Statement*>(call_super ? 2 : 1, zone());
if (call_super) {
// Create a SuperCallReference and handle in BytecodeGenerator.
auto constructor_args_name = ast_value_factory()->empty_string();
bool is_duplicate;
bool is_rest = true;
bool is_optional = false;
Variable* constructor_args = function_scope->DeclareParameter(
constructor_args_name, TEMPORARY, is_optional, is_rest, &is_duplicate,
ast_value_factory(), pos);
ZoneList<Expression*>* args =
new (zone()) ZoneList<Expression*>(1, zone());
Spread* spread_args = factory()->NewSpread(
factory()->NewVariableProxy(constructor_args), pos, pos);
args->Add(spread_args, zone());
Expression* super_call_ref = NewSuperCallReference(pos);
Expression* call = factory()->NewCall(super_call_ref, args, pos);
body->Add(factory()->NewReturnStatement(call, pos), zone());
}
expected_property_count = function_state.expected_property_count();
}
FunctionLiteral* function_literal = factory()->NewFunctionLiteral(
name, function_scope, body, expected_property_count, parameter_count,
parameter_count, FunctionLiteral::kNoDuplicateParameters,
FunctionLiteral::kAnonymousExpression, default_eager_compile_hint(), pos,
true, GetNextFunctionLiteralId());
return function_literal;
}
// ----------------------------------------------------------------------------
// The CHECK_OK macro is a convenient macro to enforce error
// handling for functions that may fail (by returning !*ok).
//
// CAUTION: This macro appends extra statements after a call,
// thus it must never be used where only a single statement
// is correct (e.g. an if statement branch w/o braces)!
#define CHECK_OK_VALUE(x) ok); \
if (!*ok) return x; \
((void)0
#define DUMMY ) // to make indentation work
#undef DUMMY
#define CHECK_OK CHECK_OK_VALUE(nullptr)
#define CHECK_OK_VOID CHECK_OK_VALUE(this->Void())
#define CHECK_FAILED /**/); \
if (failed_) return nullptr; \
((void)0
#define DUMMY ) // to make indentation work
#undef DUMMY
// ----------------------------------------------------------------------------
// Implementation of Parser
bool Parser::ShortcutNumericLiteralBinaryExpression(Expression** x,
Expression* y,
Token::Value op, int pos) {
if ((*x)->IsNumberLiteral() && y->IsNumberLiteral()) {
double x_val = (*x)->AsLiteral()->AsNumber();
double y_val = y->AsLiteral()->AsNumber();
switch (op) {
case Token::ADD:
*x = factory()->NewNumberLiteral(x_val + y_val, pos);
return true;
case Token::SUB:
*x = factory()->NewNumberLiteral(x_val - y_val, pos);
return true;
case Token::MUL:
*x = factory()->NewNumberLiteral(x_val * y_val, pos);
return true;
case Token::DIV:
*x = factory()->NewNumberLiteral(x_val / y_val, pos);
return true;
case Token::BIT_OR: {
int value = DoubleToInt32(x_val) | DoubleToInt32(y_val);
*x = factory()->NewNumberLiteral(value, pos);
return true;
}
case Token::BIT_AND: {
int value = DoubleToInt32(x_val) & DoubleToInt32(y_val);
*x = factory()->NewNumberLiteral(value, pos);
return true;
}
case Token::BIT_XOR: {
int value = DoubleToInt32(x_val) ^ DoubleToInt32(y_val);
*x = factory()->NewNumberLiteral(value, pos);
return true;
}
case Token::SHL: {
int value = DoubleToInt32(x_val) << (DoubleToInt32(y_val) & 0x1F);
*x = factory()->NewNumberLiteral(value, pos);
return true;
}
case Token::SHR: {
uint32_t shift = DoubleToInt32(y_val) & 0x1F;
uint32_t value = DoubleToUint32(x_val) >> shift;
*x = factory()->NewNumberLiteral(value, pos);
return true;
}
case Token::SAR: {
uint32_t shift = DoubleToInt32(y_val) & 0x1F;
int value = ArithmeticShiftRight(DoubleToInt32(x_val), shift);
*x = factory()->NewNumberLiteral(value, pos);
return true;
}
case Token::EXP: {
double value = Pow(x_val, y_val);
int int_value = static_cast<int>(value);
*x = factory()->NewNumberLiteral(
int_value == value && value != -0.0 ? int_value : value, pos);
return true;
}
default:
break;
}
}
return false;
}
bool Parser::CollapseNaryExpression(Expression** x, Expression* y,
Token::Value op, int pos,
const SourceRange& range) {
// Filter out unsupported ops.
if (!Token::IsBinaryOp(op) || op == Token::EXP) return false;
// Convert *x into an nary operation with the given op, returning false if
// this is not possible.
NaryOperation* nary = nullptr;
if ((*x)->IsBinaryOperation()) {
BinaryOperation* binop = (*x)->AsBinaryOperation();
if (binop->op() != op) return false;
nary = factory()->NewNaryOperation(op, binop->left(), 2);
nary->AddSubsequent(binop->right(), binop->position());
ConvertBinaryToNaryOperationSourceRange(binop, nary);
*x = nary;
} else if ((*x)->IsNaryOperation()) {
nary = (*x)->AsNaryOperation();
if (nary->op() != op) return false;
} else {
return false;
}
// Append our current expression to the nary operation.
// TODO(leszeks): Do some literal collapsing here if we're appending Smi or
// String literals.
nary->AddSubsequent(y, pos);
AppendNaryOperationSourceRange(nary, range);
return true;
}
Expression* Parser::BuildUnaryExpression(Expression* expression,
Token::Value op, int pos) {
DCHECK_NOT_NULL(expression);
const Literal* literal = expression->AsLiteral();
if (literal != nullptr) {
if (op == Token::NOT) {
// Convert the literal to a boolean condition and negate it.
return factory()->NewBooleanLiteral(literal->ToBooleanIsFalse(), pos);
} else if (literal->IsNumberLiteral()) {
// Compute some expressions involving only number literals.
double value = literal->AsNumber();
switch (op) {
case Token::ADD:
return expression;
case Token::SUB:
return factory()->NewNumberLiteral(-value, pos);
case Token::BIT_NOT:
return factory()->NewNumberLiteral(~DoubleToInt32(value), pos);
default:
break;
}
}
}
return factory()->NewUnaryOperation(op, expression, pos);
}
Expression* Parser::NewThrowError(Runtime::FunctionId id,
MessageTemplate::Template message,
const AstRawString* arg, int pos) {
ZoneList<Expression*>* args = new (zone()) ZoneList<Expression*>(2, zone());
args->Add(factory()->NewSmiLiteral(message, pos), zone());
args->Add(factory()->NewStringLiteral(arg, pos), zone());
CallRuntime* call_constructor = factory()->NewCallRuntime(id, args, pos);
return factory()->NewThrow(call_constructor, pos);
}
Expression* Parser::NewSuperPropertyReference(int pos) {
// this_function[home_object_symbol]
VariableProxy* this_function_proxy =
NewUnresolved(ast_value_factory()->this_function_string(), pos);
Expression* home_object_symbol_literal = factory()->NewSymbolLiteral(
AstSymbol::kHomeObjectSymbol, kNoSourcePosition);
Expression* home_object = factory()->NewProperty(
this_function_proxy, home_object_symbol_literal, pos);
return factory()->NewSuperPropertyReference(
ThisExpression(pos)->AsVariableProxy(), home_object, pos);
}
Expression* Parser::NewSuperCallReference(int pos) {
VariableProxy* new_target_proxy =
NewUnresolved(ast_value_factory()->new_target_string(), pos);
VariableProxy* this_function_proxy =
NewUnresolved(ast_value_factory()->this_function_string(), pos);
return factory()->NewSuperCallReference(
ThisExpression(pos)->AsVariableProxy(), new_target_proxy,
this_function_proxy, pos);
}
Expression* Parser::NewTargetExpression(int pos) {
auto proxy = NewUnresolved(ast_value_factory()->new_target_string(), pos);
proxy->set_is_new_target();
return proxy;
}
Expression* Parser::FunctionSentExpression(int pos) {
// We desugar function.sent into %_GeneratorGetInputOrDebugPos(generator).
ZoneList<Expression*>* args = new (zone()) ZoneList<Expression*>(1, zone());
VariableProxy* generator = factory()->NewVariableProxy(
function_state_->scope()->generator_object_var());
args->Add(generator, zone());
return factory()->NewCallRuntime(Runtime::kInlineGeneratorGetInputOrDebugPos,
args, pos);
}
Expression* Parser::ImportMetaExpression(int pos) {
return factory()->NewCallRuntime(
Runtime::kInlineGetImportMetaObject,
new (zone()) ZoneList<Expression*>(0, zone()), pos);
}
Literal* Parser::ExpressionFromLiteral(Token::Value token, int pos) {
switch (token) {
case Token::NULL_LITERAL:
return factory()->NewNullLiteral(pos);
case Token::TRUE_LITERAL:
return factory()->NewBooleanLiteral(true, pos);
case Token::FALSE_LITERAL:
return factory()->NewBooleanLiteral(false, pos);
case Token::SMI: {
uint32_t value = scanner()->smi_value();
return factory()->NewSmiLiteral(value, pos);
}
case Token::NUMBER: {
double value = scanner()->DoubleValue();
return factory()->NewNumberLiteral(value, pos);
}
case Token::BIGINT:
return factory()->NewBigIntLiteral(
AstBigInt(scanner()->CurrentLiteralAsCString(zone())), pos);
default:
DCHECK(false);
}
return nullptr;
}
Expression* Parser::NewV8Intrinsic(const AstRawString* name,
ZoneList<Expression*>* args, int pos,
bool* ok) {
if (extension_ != nullptr) {
// The extension structures are only accessible while parsing the
// very first time, not when reparsing because of lazy compilation.
GetClosureScope()->ForceEagerCompilation();
}
DCHECK(name->is_one_byte());
const Runtime::Function* function =
Runtime::FunctionForName(name->raw_data(), name->length());
if (function != nullptr) {
// Check for possible name clash.
DCHECK_EQ(Context::kNotFound,
Context::IntrinsicIndexForName(name->raw_data(), name->length()));
// Check for built-in IS_VAR macro.
if (function->function_id == Runtime::kIS_VAR) {
DCHECK_EQ(Runtime::RUNTIME, function->intrinsic_type);
// %IS_VAR(x) evaluates to x if x is a variable,
// leads to a parse error otherwise. Could be implemented as an
// inline function %_IS_VAR(x) to eliminate this special case.
if (args->length() == 1 && args->at(0)->AsVariableProxy() != nullptr) {
return args->at(0);
} else {
ReportMessage(MessageTemplate::kNotIsvar);
*ok = false;
return nullptr;
}
}
// Check that the expected number of arguments are being passed.
if (function->nargs != -1 && function->nargs != args->length()) {
ReportMessage(MessageTemplate::kRuntimeWrongNumArgs);
*ok = false;
return nullptr;
}
return factory()->NewCallRuntime(function, args, pos);
}
int context_index =
Context::IntrinsicIndexForName(name->raw_data(), name->length());
// Check that the function is defined.
if (context_index == Context::kNotFound) {
ReportMessage(MessageTemplate::kNotDefined, name);
*ok = false;
return nullptr;
}
return factory()->NewCallRuntime(context_index, args, pos);
}
Parser::Parser(ParseInfo* info)
: ParserBase<Parser>(info->zone(), &scanner_, info->stack_limit(),
info->extension(), info->GetOrCreateAstValueFactory(),
info->pending_error_handler(),
info->runtime_call_stats(), info->logger(),
info->script().is_null() ? -1 : info->script()->id(),
info->is_module(), true),
scanner_(info->unicode_cache()),
reusable_preparser_(nullptr),
mode_(PARSE_EAGERLY), // Lazy mode must be set explicitly.
source_range_map_(info->source_range_map()),
target_stack_(nullptr),
compile_options_(info->compile_options()),
cached_parse_data_(nullptr),
total_preparse_skipped_(0),
temp_zoned_(false),
log_(nullptr),
consumed_preparsed_scope_data_(info->consumed_preparsed_scope_data()),
parameters_end_pos_(info->parameters_end_pos()) {
// Even though we were passed ParseInfo, we should not store it in
// Parser - this makes sure that Isolate is not accidentally accessed via
// ParseInfo during background parsing.
DCHECK_NOT_NULL(info->character_stream());
// Determine if functions can be lazily compiled. This is necessary to
// allow some of our builtin JS files to be lazily compiled. These
// builtins cannot be handled lazily by the parser, since we have to know
// if a function uses the special natives syntax, which is something the
// parser records.
// If the debugger requests compilation for break points, we cannot be
// aggressive about lazy compilation, because it might trigger compilation
// of functions without an outer context when setting a breakpoint through
// Debug::FindSharedFunctionInfoInScript
// We also compile eagerly for kProduceExhaustiveCodeCache.
bool can_compile_lazily = FLAG_lazy && !info->is_eager();
set_default_eager_compile_hint(can_compile_lazily
? FunctionLiteral::kShouldLazyCompile
: FunctionLiteral::kShouldEagerCompile);
allow_lazy_ = FLAG_lazy && info->allow_lazy_parsing() && !info->is_native() &&
info->extension() == nullptr && can_compile_lazily;
set_allow_natives(FLAG_allow_natives_syntax || info->is_native());
set_allow_harmony_do_expressions(FLAG_harmony_do_expressions);
set_allow_harmony_function_sent(FLAG_harmony_function_sent);
set_allow_harmony_public_fields(FLAG_harmony_public_fields);
set_allow_harmony_dynamic_import(FLAG_harmony_dynamic_import);
set_allow_harmony_import_meta(FLAG_harmony_import_meta);
set_allow_harmony_async_iteration(FLAG_harmony_async_iteration);
set_allow_harmony_bigint(FLAG_harmony_bigint);
for (int feature = 0; feature < v8::Isolate::kUseCounterFeatureCount;
++feature) {
use_counts_[feature] = 0;
}
}
void Parser::DeserializeScopeChain(
ParseInfo* info, MaybeHandle<ScopeInfo> maybe_outer_scope_info) {
// TODO(wingo): Add an outer SCRIPT_SCOPE corresponding to the native
// context, which will have the "this" binding for script scopes.
DeclarationScope* script_scope = NewScriptScope();
info->set_script_scope(script_scope);
Scope* scope = script_scope;
Handle<ScopeInfo> outer_scope_info;
if (maybe_outer_scope_info.ToHandle(&outer_scope_info)) {
DCHECK(ThreadId::Current().Equals(
outer_scope_info->GetIsolate()->thread_id()));
scope = Scope::DeserializeScopeChain(
zone(), *outer_scope_info, script_scope, ast_value_factory(),
Scope::DeserializationMode::kScopesOnly);
}
original_scope_ = scope;
}
namespace {
void MaybeResetCharacterStream(ParseInfo* info, FunctionLiteral* literal) {
// Don't reset the character stream if there is an asm.js module since it will
// be used again by the asm-parser.
if (!FLAG_stress_validate_asm &&
(literal == nullptr || !literal->scope()->ContainsAsmModule())) {
info->ResetCharacterStream();
}
}
} // namespace
FunctionLiteral* Parser::ParseProgram(Isolate* isolate, ParseInfo* info) {
// TODO(bmeurer): We temporarily need to pass allow_nesting = true here,
// see comment for HistogramTimerScope class.
// It's OK to use the Isolate & counters here, since this function is only
// called in the main thread.
DCHECK(parsing_on_main_thread_);
RuntimeCallTimerScope runtime_timer(
runtime_call_stats_, info->is_eval()
? RuntimeCallCounterId::kParseEval
: RuntimeCallCounterId::kParseProgram);
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"), "V8.ParseProgram");
base::ElapsedTimer timer;
if (V8_UNLIKELY(FLAG_log_function_events)) timer.Start();
fni_ = new (zone()) FuncNameInferrer(ast_value_factory(), zone());
// Initialize parser state.
ParserLogger logger;
if (produce_cached_parse_data()) {
if (allow_lazy_) {
log_ = &logger;
} else {
compile_options_ = ScriptCompiler::kNoCompileOptions;
}
} else if (consume_cached_parse_data()) {
cached_parse_data_->Initialize();
}
DeserializeScopeChain(info, info->maybe_outer_scope_info());
scanner_.Initialize(info->character_stream(), info->is_module());
FunctionLiteral* result = DoParseProgram(info);
MaybeResetCharacterStream(info, result);
HandleSourceURLComments(isolate, info->script());
if (produce_cached_parse_data() && result != nullptr) {
*info->cached_data() = logger.GetScriptData();
}
log_ = nullptr;
if (V8_UNLIKELY(FLAG_log_function_events) && result != nullptr) {
double ms = timer.Elapsed().InMillisecondsF();
const char* event_name = "parse-eval";
Script* script = *info->script();
int start = -1;
int end = -1;
if (!info->is_eval()) {
event_name = "parse-script";
start = 0;
end = String::cast(script->source())->length();
}
LOG(script->GetIsolate(),
FunctionEvent(event_name, script, -1, ms, start, end, "", 0));
}
return result;
}
FunctionLiteral* Parser::DoParseProgram(ParseInfo* info) {
// Note that this function can be called from the main thread or from a
// background thread. We should not access anything Isolate / heap dependent
// via ParseInfo, and also not pass it forward.
DCHECK_NULL(scope_);
DCHECK_NULL(target_stack_);
ParsingModeScope mode(this, allow_lazy_ ? PARSE_LAZILY : PARSE_EAGERLY);
ResetFunctionLiteralId();
DCHECK(info->function_literal_id() == FunctionLiteral::kIdTypeTopLevel ||
info->function_literal_id() == FunctionLiteral::kIdTypeInvalid);
FunctionLiteral* result = nullptr;
{
Scope* outer = original_scope_;
DCHECK_NOT_NULL(outer);
if (info->is_eval()) {
outer = NewEvalScope(outer);
} else if (parsing_module_) {
DCHECK_EQ(outer, info->script_scope());
outer = NewModuleScope(info->script_scope());
}
DeclarationScope* scope = outer->AsDeclarationScope();
scope->set_start_position(0);
FunctionState function_state(&function_state_, &scope_, scope);
ZoneList<Statement*>* body = new(zone()) ZoneList<Statement*>(16, zone());
bool ok = true;
int beg_pos = scanner()->location().beg_pos;
if (parsing_module_) {
DCHECK(info->is_module());
// Declare the special module parameter.
auto name = ast_value_factory()->empty_string();
bool is_duplicate = false;
bool is_rest = false;
bool is_optional = false;
auto var =
scope->DeclareParameter(name, VAR, is_optional, is_rest,
&is_duplicate, ast_value_factory(), beg_pos);
DCHECK(!is_duplicate);
var->AllocateTo(VariableLocation::PARAMETER, 0);
PrepareGeneratorVariables();
Expression* initial_yield =
BuildInitialYield(kNoSourcePosition, kGeneratorFunction);
body->Add(
factory()->NewExpressionStatement(initial_yield, kNoSourcePosition),
zone());
ParseModuleItemList(body, &ok);
ok = ok && module()->Validate(this->scope()->AsModuleScope(),
pending_error_handler(), zone());
} else {
// Don't count the mode in the use counters--give the program a chance
// to enable script-wide strict mode below.
this->scope()->SetLanguageMode(info->language_mode());
ParseStatementList(body, Token::EOS, &ok);
}
// The parser will peek but not consume EOS. Our scope logically goes all
// the way to the EOS, though.
scope->set_end_position(scanner()->peek_location().beg_pos);
if (ok && is_strict(language_mode())) {
CheckStrictOctalLiteral(beg_pos, scanner()->location().end_pos, &ok);
}
if (ok && is_sloppy(language_mode())) {
// TODO(littledan): Function bindings on the global object that modify
// pre-existing bindings should be made writable, enumerable and
// nonconfigurable if possible, whereas this code will leave attributes
// unchanged if the property already exists.
InsertSloppyBlockFunctionVarBindings(scope);
}
if (ok) {
CheckConflictingVarDeclarations(scope, &ok);
}
if (ok && info->parse_restriction() == ONLY_SINGLE_FUNCTION_LITERAL) {
if (body->length() != 1 ||
!body->at(0)->IsExpressionStatement() ||
!body->at(0)->AsExpressionStatement()->
expression()->IsFunctionLiteral()) {
ReportMessage(MessageTemplate::kSingleFunctionLiteral);
ok = false;
}
}
if (ok) {
RewriteDestructuringAssignments();
int parameter_count = parsing_module_ ? 1 : 0;
result = factory()->NewScriptOrEvalFunctionLiteral(
scope, body, function_state.expected_property_count(),
parameter_count);
}
}
info->set_max_function_literal_id(GetLastFunctionLiteralId());
// Make sure the target stack is empty.
DCHECK_NULL(target_stack_);
return result;
}
FunctionLiteral* Parser::ParseFunction(Isolate* isolate, ParseInfo* info,
Handle<SharedFunctionInfo> shared_info) {
// It's OK to use the Isolate & counters here, since this function is only
// called in the main thread.
DCHECK(parsing_on_main_thread_);
RuntimeCallTimerScope runtime_timer(runtime_call_stats_,
RuntimeCallCounterId::kParseFunction);
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"), "V8.ParseFunction");
base::ElapsedTimer timer;
if (V8_UNLIKELY(FLAG_log_function_events)) timer.Start();
DeserializeScopeChain(info, info->maybe_outer_scope_info());
DCHECK_EQ(factory()->zone(), info->zone());
// Initialize parser state.
Handle<String> name(shared_info->name());
info->set_function_name(ast_value_factory()->GetString(name));
scanner_.Initialize(info->character_stream(), info->is_module());
FunctionLiteral* result = DoParseFunction(info, info->function_name());
MaybeResetCharacterStream(info, result);
if (result != nullptr) {
Handle<String> inferred_name(shared_info->inferred_name());
result->set_inferred_name(inferred_name);
}
if (V8_UNLIKELY(FLAG_log_function_events) && result != nullptr) {
double ms = timer.Elapsed().InMillisecondsF();
// We need to make sure that the debug-name is available.
ast_value_factory()->Internalize(isolate);
DeclarationScope* function_scope = result->scope();
Script* script = *info->script();
std::unique_ptr<char[]> function_name = result->GetDebugName();
LOG(script->GetIsolate(),
FunctionEvent("parse-function", script, -1, ms,
function_scope->start_position(),
function_scope->end_position(), function_name.get(),
strlen(function_name.get())));
}
return result;
}
static FunctionLiteral::FunctionType ComputeFunctionType(ParseInfo* info) {
if (info->is_declaration()) {
return FunctionLiteral::kDeclaration;
} else if (info->is_named_expression()) {
return FunctionLiteral::kNamedExpression;
} else if (IsConciseMethod(info->function_kind()) ||
IsAccessorFunction(info->function_kind())) {
return FunctionLiteral::kAccessorOrMethod;
}
return FunctionLiteral::kAnonymousExpression;
}
FunctionLiteral* Parser::DoParseFunction(ParseInfo* info,
const AstRawString* raw_name) {
DCHECK_NOT_NULL(raw_name);
DCHECK_NULL(scope_);
DCHECK_NULL(target_stack_);
DCHECK(ast_value_factory());
fni_ = new (zone()) FuncNameInferrer(ast_value_factory(), zone());
fni_->PushEnclosingName(raw_name);
ResetFunctionLiteralId();
DCHECK_LT(0, info->function_literal_id());
SkipFunctionLiterals(info->function_literal_id() - 1);
ParsingModeScope parsing_mode(this, PARSE_EAGERLY);
// Place holder for the result.
FunctionLiteral* result = nullptr;
{
// Parse the function literal.
Scope* outer = original_scope_;
DeclarationScope* outer_function = outer->GetClosureScope();
DCHECK(outer);
FunctionState function_state(&function_state_, &scope_, outer_function);
BlockState block_state(&scope_, outer);
DCHECK(is_sloppy(outer->language_mode()) ||
is_strict(info->language_mode()));
FunctionLiteral::FunctionType function_type = ComputeFunctionType(info);
FunctionKind kind = info->function_kind();
bool ok = true;
if (IsArrowFunction(kind)) {
if (IsAsyncFunction(kind)) {
DCHECK(!scanner()->HasAnyLineTerminatorAfterNext());
if (!Check(Token::ASYNC)) {
CHECK(stack_overflow());
return nullptr;
}
if (!(peek_any_identifier() || peek() == Token::LPAREN)) {
CHECK(stack_overflow());
return nullptr;
}
}
// TODO(adamk): We should construct this scope from the ScopeInfo.
DeclarationScope* scope = NewFunctionScope(kind);
// This bit only needs to be explicitly set because we're
// not passing the ScopeInfo to the Scope constructor.
SetLanguageMode(scope, info->language_mode());
scope->set_start_position(info->start_position());
ExpressionClassifier formals_classifier(this);
ParserFormalParameters formals(scope);
int rewritable_length =
function_state.destructuring_assignments_to_rewrite().length();
{
// Parsing patterns as variable reference expression creates
// NewUnresolved references in current scope. Enter arrow function
// scope for formal parameter parsing.
BlockState block_state(&scope_, scope);
if (Check(Token::LPAREN)) {
// '(' StrictFormalParameters ')'
ParseFormalParameterList(&formals, &ok);
if (ok) ok = Check(Token::RPAREN);
} else {
// BindingIdentifier
ParseFormalParameter(&formals, &ok);
if (ok) {
DeclareFormalParameters(formals.scope, formals.params,
formals.is_simple);
}
}
}
if (ok) {
if (GetLastFunctionLiteralId() != info->function_literal_id() - 1) {
// If there were FunctionLiterals in the parameters, we need to
// renumber them to shift down so the next function literal id for
// the arrow function is the one requested.
AstFunctionLiteralIdReindexer reindexer(
stack_limit_,
(info->function_literal_id() - 1) - GetLastFunctionLiteralId());
for (auto p : formals.params) {
if (p->pattern != nullptr) reindexer.Reindex(p->pattern);
if (p->initializer != nullptr) reindexer.Reindex(p->initializer);
}
ResetFunctionLiteralId();
SkipFunctionLiterals(info->function_literal_id() - 1);
}
// Pass `accept_IN=true` to ParseArrowFunctionLiteral --- This should
// not be observable, or else the preparser would have failed.
Expression* expression =
ParseArrowFunctionLiteral(true, formals, rewritable_length, &ok);
if (ok) {
// Scanning must end at the same position that was recorded
// previously. If not, parsing has been interrupted due to a stack
// overflow, at which point the partially parsed arrow function
// concise body happens to be a valid expression. This is a problem
// only for arrow functions with single expression bodies, since there
// is no end token such as "}" for normal functions.
if (scanner()->location().end_pos == info->end_position()) {
// The pre-parser saw an arrow function here, so the full parser
// must produce a FunctionLiteral.
DCHECK(expression->IsFunctionLiteral());
result = expression->AsFunctionLiteral();
// Rewrite destructuring assignments in the parameters. (The ones
// inside the function body are rewritten by
// ParseArrowFunctionLiteral.)
RewriteDestructuringAssignments();
} else {
ok = false;
}
}
}
} else if (IsDefaultConstructor(kind)) {
DCHECK_EQ(scope(), outer);
result = DefaultConstructor(raw_name, IsDerivedConstructor(kind),
info->start_position(), info->end_position());
} else {
result = ParseFunctionLiteral(
raw_name, Scanner::Location::invalid(), kSkipFunctionNameCheck, kind,
kNoSourcePosition, function_type, info->language_mode(), &ok);
}
if (ok) {
result->set_requires_instance_fields_initializer(
info->requires_instance_fields_initializer());
}
// Make sure the results agree.
DCHECK(ok == (result != nullptr));
}
// Make sure the target stack is empty.
DCHECK_NULL(target_stack_);
DCHECK_IMPLIES(result,
info->function_literal_id() == result->function_literal_id());
return result;
}
Statement* Parser::ParseModuleItem(bool* ok) {
// ecma262/#prod-ModuleItem
// ModuleItem :
// ImportDeclaration
// ExportDeclaration
// StatementListItem
Token::Value next = peek();
if (next == Token::EXPORT) {
return ParseExportDeclaration(ok);
}
if (next == Token::IMPORT) {
// We must be careful not to parse a dynamic import expression as an import
// declaration. Same for import.meta expressions.
Token::Value peek_ahead = PeekAhead();
if ((!allow_harmony_dynamic_import() || peek_ahead != Token::LPAREN) &&
(!allow_harmony_import_meta() || peek_ahead != Token::PERIOD)) {
ParseImportDeclaration(CHECK_OK);
return factory()->NewEmptyStatement(kNoSourcePosition);
}
}
return ParseStatementListItem(ok);
}
void Parser::ParseModuleItemList(ZoneList<Statement*>* body, bool* ok) {
// ecma262/#prod-Module
// Module :
// ModuleBody?
//
// ecma262/#prod-ModuleItemList
// ModuleBody :
// ModuleItem*
DCHECK(scope()->is_module_scope());
while (peek() != Token::EOS) {
Statement* stat = ParseModuleItem(CHECK_OK_VOID);
if (stat && !stat->IsEmpty()) {
body->Add(stat, zone());
}
}
}
const AstRawString* Parser::ParseModuleSpecifier(bool* ok) {
// ModuleSpecifier :
// StringLiteral
Expect(Token::STRING, CHECK_OK);
return GetSymbol();
}
void Parser::ParseExportClause(ZoneList<const AstRawString*>* export_names,
ZoneList<Scanner::Location>* export_locations,
ZoneList<const AstRawString*>* local_names,
Scanner::Location* reserved_loc, bool* ok) {
// ExportClause :
// '{' '}'
// '{' ExportsList '}'
// '{' ExportsList ',' '}'
//
// ExportsList :
// ExportSpecifier
// ExportsList ',' ExportSpecifier
//
// ExportSpecifier :
// IdentifierName
// IdentifierName 'as' IdentifierName
Expect(Token::LBRACE, CHECK_OK_VOID);
Token::Value name_tok;
while ((name_tok = peek()) != Token::RBRACE) {
// Keep track of the first reserved word encountered in case our
// caller needs to report an error.
if (!reserved_loc->IsValid() &&
!Token::IsIdentifier(name_tok, LanguageMode::kStrict, false,
parsing_module_)) {
*reserved_loc = scanner()->location();
}
const AstRawString* local_name = ParseIdentifierName(CHECK_OK_VOID);
const AstRawString* export_name = nullptr;
Scanner::Location location = scanner()->location();
if (CheckContextualKeyword(Token::AS)) {
export_name = ParseIdentifierName(CHECK_OK_VOID);
// Set the location to the whole "a as b" string, so that it makes sense
// both for errors due to "a" and for errors due to "b".
location.end_pos = scanner()->location().end_pos;
}
if (export_name == nullptr) {
export_name = local_name;
}
export_names->Add(export_name, zone());
local_names->Add(local_name, zone());
export_locations->Add(location, zone());
if (peek() == Token::RBRACE) break;
Expect(Token::COMMA, CHECK_OK_VOID);
}
Expect(Token::RBRACE, CHECK_OK_VOID);
}
ZoneList<const Parser::NamedImport*>* Parser::ParseNamedImports(
int pos, bool* ok) {
// NamedImports :
// '{' '}'
// '{' ImportsList '}'
// '{' ImportsList ',' '}'
//
// ImportsList :
// ImportSpecifier
// ImportsList ',' ImportSpecifier
//
// ImportSpecifier :
// BindingIdentifier
// IdentifierName 'as' BindingIdentifier
Expect(Token::LBRACE, CHECK_OK);
auto result = new (zone()) ZoneList<const NamedImport*>(1, zone());
while (peek() != Token::RBRACE) {
const AstRawString* import_name = ParseIdentifierName(CHECK_OK);
const AstRawString* local_name = import_name;
Scanner::Location location = scanner()->location();
// In the presence of 'as', the left-side of the 'as' can
// be any IdentifierName. But without 'as', it must be a valid
// BindingIdentifier.
if (CheckContextualKeyword(Token::AS)) {
local_name = ParseIdentifierName(CHECK_OK);
}
if (!Token::IsIdentifier(scanner()->current_token(), LanguageMode::kStrict,
false, parsing_module_)) {
*ok = false;
ReportMessage(MessageTemplate::kUnexpectedReserved);
return nullptr;
} else if (IsEvalOrArguments(local_name)) {
*ok = false;
ReportMessage(MessageTemplate::kStrictEvalArguments);
return nullptr;
}
DeclareVariable(local_name, CONST, kNeedsInitialization, position(),
CHECK_OK);
NamedImport* import =
new (zone()) NamedImport(import_name, local_name, location);
result->Add(import, zone());
if (peek() == Token::RBRACE) break;
Expect(Token::COMMA, CHECK_OK);
}
Expect(Token::RBRACE, CHECK_OK);
return result;
}
void Parser::ParseImportDeclaration(bool* ok) {
// ImportDeclaration :
// 'import' ImportClause 'from' ModuleSpecifier ';'
// 'import' ModuleSpecifier ';'
//
// ImportClause :
// ImportedDefaultBinding
// NameSpaceImport
// NamedImports
// ImportedDefaultBinding ',' NameSpaceImport
// ImportedDefaultBinding ',' NamedImports
//
// NameSpaceImport :
// '*' 'as' ImportedBinding
int pos = peek_position();
Expect(Token::IMPORT, CHECK_OK_VOID);
Token::Value tok = peek();
// 'import' ModuleSpecifier ';'
if (tok == Token::STRING) {
Scanner::Location specifier_loc = scanner()->peek_location();
const AstRawString* module_specifier = ParseModuleSpecifier(CHECK_OK_VOID);
ExpectSemicolon(CHECK_OK_VOID);
module()->AddEmptyImport(module_specifier, specifier_loc);
return;
}
// Parse ImportedDefaultBinding if present.
const AstRawString* import_default_binding = nullptr;
Scanner::Location import_default_binding_loc;
if (tok != Token::MUL && tok != Token::LBRACE) {
import_default_binding =
ParseIdentifier(kDontAllowRestrictedIdentifiers, CHECK_OK_VOID);
import_default_binding_loc = scanner()->location();
DeclareVariable(import_default_binding, CONST, kNeedsInitialization, pos,
CHECK_OK_VOID);
}
// Parse NameSpaceImport or NamedImports if present.
const AstRawString* module_namespace_binding = nullptr;
Scanner::Location module_namespace_binding_loc;
const ZoneList<const NamedImport*>* named_imports = nullptr;
if (import_default_binding == nullptr || Check(Token::COMMA)) {
switch (peek()) {
case Token::MUL: {
Consume(Token::MUL);
ExpectContextualKeyword(Token::AS, CHECK_OK_VOID);
module_namespace_binding =
ParseIdentifier(kDontAllowRestrictedIdentifiers, CHECK_OK_VOID);
module_namespace_binding_loc = scanner()->location();
DeclareVariable(module_namespace_binding, CONST, kCreatedInitialized,
pos, CHECK_OK_VOID);
break;
}
case Token::LBRACE:
named_imports = ParseNamedImports(pos, CHECK_OK_VOID);
break;
default:
*ok = false;
ReportUnexpectedToken(scanner()->current_token());
return;
}
}
ExpectContextualKeyword(Token::FROM, CHECK_OK_VOID);
Scanner::Location specifier_loc = scanner()->peek_location();
const AstRawString* module_specifier = ParseModuleSpecifier(CHECK_OK_VOID);
ExpectSemicolon(CHECK_OK_VOID);
// Now that we have all the information, we can make the appropriate
// declarations.
// TODO(neis): Would prefer to call DeclareVariable for each case below rather
// than above and in ParseNamedImports, but then a possible error message
// would point to the wrong location. Maybe have a DeclareAt version of
// Declare that takes a location?
if (module_namespace_binding != nullptr) {
module()->AddStarImport(module_namespace_binding, module_specifier,
module_namespace_binding_loc, specifier_loc,
zone());
}
if (import_default_binding != nullptr) {
module()->AddImport(ast_value_factory()->default_string(),
import_default_binding, module_specifier,
import_default_binding_loc, specifier_loc, zone());
}
if (named_imports != nullptr) {
if (named_imports->length() == 0) {
module()->AddEmptyImport(module_specifier, specifier_loc);
} else {
for (int i = 0; i < named_imports->length(); ++i) {
const NamedImport* import = named_imports->at(i);
module()->AddImport(import->import_name, import->local_name,
module_specifier, import->location, specifier_loc,
zone());
}
}
}
}
Statement* Parser::ParseExportDefault(bool* ok) {
// Supports the following productions, starting after the 'default' token:
// 'export' 'default' HoistableDeclaration
// 'export' 'default' ClassDeclaration
// 'export' 'default' AssignmentExpression[In] ';'
Expect(Token::DEFAULT, CHECK_OK);
Scanner::Location default_loc = scanner()->location();
ZoneList<const AstRawString*> local_names(1, zone());
Statement* result = nullptr;
switch (peek()) {
case Token::FUNCTION:
result = ParseHoistableDeclaration(&local_names, true, CHECK_OK);
break;
case Token::CLASS:
Consume(Token::CLASS);
result = ParseClassDeclaration(&local_names, true, CHECK_OK);
break;
case Token::ASYNC:
if (PeekAhead() == Token::FUNCTION &&
!scanner()->HasAnyLineTerminatorAfterNext()) {
Consume(Token::ASYNC);
result = ParseAsyncFunctionDeclaration(&local_names, true, CHECK_OK);
break;
}
/* falls through */
default: {
int pos = position();
ExpressionClassifier classifier(this);
Expression* value = ParseAssignmentExpression(true, CHECK_OK);
RewriteNonPattern(CHECK_OK);
SetFunctionName(value, ast_value_factory()->default_string());
const AstRawString* local_name =
ast_value_factory()->star_default_star_string();
local_names.Add(local_name, zone());
// It's fine to declare this as CONST because the user has no way of
// writing to it.
Declaration* decl = DeclareVariable(local_name, CONST, pos, CHECK_OK);
decl->proxy()->var()->set_initializer_position(position());
Assignment* assignment = factory()->NewAssignment(
Token::INIT, decl->proxy(), value, kNoSourcePosition);
result = IgnoreCompletion(
factory()->NewExpressionStatement(assignment, kNoSourcePosition));
ExpectSemicolon(CHECK_OK);
break;
}
}
DCHECK_EQ(local_names.length(), 1);
module()->AddExport(local_names.first(),
ast_value_factory()->default_string(), default_loc,
zone());
DCHECK_NOT_NULL(result);
return result;
}
Statement* Parser::ParseExportDeclaration(bool* ok) {
// ExportDeclaration:
// 'export' '*' 'from' ModuleSpecifier ';'
// 'export' ExportClause ('from' ModuleSpecifier)? ';'
// 'export' VariableStatement
// 'export' Declaration
// 'export' 'default' ... (handled in ParseExportDefault)
Expect(Token::EXPORT, CHECK_OK);
int pos = position();
Statement* result = nullptr;
ZoneList<const AstRawString*> names(1, zone());
Scanner::Location loc = scanner()->peek_location();
switch (peek()) {
case Token::DEFAULT:
return ParseExportDefault(ok);
case Token::MUL: {
Consume(Token::MUL);
loc = scanner()->location();
ExpectContextualKeyword(Token::FROM, CHECK_OK);
Scanner::Location specifier_loc = scanner()->peek_location();
const AstRawString* module_specifier = ParseModuleSpecifier(CHECK_OK);
ExpectSemicolon(CHECK_OK);
module()->AddStarExport(module_specifier, loc, specifier_loc, zone());
return factory()->NewEmptyStatement(pos);
}
case Token::LBRACE: {
// There are two cases here:
//
// 'export' ExportClause ';'
// and
// 'export' ExportClause FromClause ';'
//
// In the first case, the exported identifiers in ExportClause must
// not be reserved words, while in the latter they may be. We
// pass in a location that gets filled with the first reserved word
// encountered, and then throw a SyntaxError if we are in the
// non-FromClause case.
Scanner::Location reserved_loc = Scanner::Location::invalid();
ZoneList<const AstRawString*> export_names(1, zone());
ZoneList<Scanner::Location> export_locations(1, zone());
ZoneList<const AstRawString*> original_names(1, zone());
ParseExportClause(&export_names, &export_locations, &original_names,
&reserved_loc, CHECK_OK);
const AstRawString* module_specifier = nullptr;
Scanner::Location specifier_loc;
if (CheckContextualKeyword(Token::FROM)) {
specifier_loc = scanner()->peek_location();
module_specifier = ParseModuleSpecifier(CHECK_OK);
} else if (reserved_loc.IsValid()) {
// No FromClause, so reserved words are invalid in ExportClause.
*ok = false;
ReportMessageAt(reserved_loc, MessageTemplate::kUnexpectedReserved);
return nullptr;
}
ExpectSemicolon(CHECK_OK);
const int length = export_names.length();
DCHECK_EQ(length, original_names.length());
DCHECK_EQ(length, export_locations.length());
if (module_specifier == nullptr) {
for (int i = 0; i < length; ++i) {
module()->AddExport(original_names[i], export_names[i],
export_locations[i], zone());
}
} else if (length == 0) {
module()->AddEmptyImport(module_specifier, specifier_loc);
} else {
for (int i = 0; i < length; ++i) {
module()->AddExport(original_names[i], export_names[i],
module_specifier, export_locations[i],
specifier_loc, zone());
}
}
return factory()->NewEmptyStatement(pos);
}
case Token::FUNCTION:
result = ParseHoistableDeclaration(&names, false, CHECK_OK);
break;
case Token::CLASS:
Consume(Token::CLASS);
result = ParseClassDeclaration(&names, false, CHECK_OK);
break;
case Token::VAR:
case Token::LET:
case Token::CONST:
result = ParseVariableStatement(kStatementListItem, &names, CHECK_OK);
break;
case Token::ASYNC:
// TODO(neis): Why don't we have the same check here as in
// ParseStatementListItem?
Consume(Token::ASYNC);
result = ParseAsyncFunctionDeclaration(&names, false, CHECK_OK);
break;
default:
*ok = false;
ReportUnexpectedToken(scanner()->current_token());
return nullptr;
}
loc.end_pos = scanner()->location().end_pos;
ModuleDescriptor* descriptor = module();
for (int i = 0; i < names.length(); ++i) {
descriptor->AddExport(names[i], names[i], loc, zone());
}
DCHECK_NOT_NULL(result);
return result;
}
VariableProxy* Parser::NewUnresolved(const AstRawString* name, int begin_pos,
VariableKind kind) {
return scope()->NewUnresolved(factory(), name, begin_pos, kind);
}
VariableProxy* Parser::NewUnresolved(const AstRawString* name) {
return scope()->NewUnresolved(factory(), name, scanner()->location().beg_pos);
}
Declaration* Parser::DeclareVariable(const AstRawString* name,
VariableMode mode, int pos, bool* ok) {
return DeclareVariable(name, mode, Variable::DefaultInitializationFlag(mode),
pos, ok);
}
Declaration* Parser::DeclareVariable(const AstRawString* name,
VariableMode mode, InitializationFlag init,
int pos, bool* ok) {
DCHECK_NOT_NULL(name);
VariableProxy* proxy = factory()->NewVariableProxy(
name, NORMAL_VARIABLE, scanner()->location().beg_pos);
Declaration* declaration;
if (mode == VAR && !scope()->is_declaration_scope()) {
DCHECK(scope()->is_block_scope() || scope()->is_with_scope());
declaration = factory()->NewNestedVariableDeclaration(proxy, scope(), pos);
} else {
declaration = factory()->NewVariableDeclaration(proxy, pos);
}
Declare(declaration, DeclarationDescriptor::NORMAL, mode, init, ok, nullptr,
scanner()->location().end_pos);
if (!*ok) return nullptr;
return declaration;
}
Variable* Parser::Declare(Declaration* declaration,
DeclarationDescriptor::Kind declaration_kind,
VariableMode mode, InitializationFlag init, bool* ok,
Scope* scope, int var_end_pos) {
if (scope == nullptr) {
scope = this->scope();
}
bool sloppy_mode_block_scope_function_redefinition = false;
Variable* variable = scope->DeclareVariable(
declaration, mode, init, &sloppy_mode_block_scope_function_redefinition,
ok);
if (!*ok) {
// If we only have the start position of a proxy, we can't highlight the
// whole variable name. Pretend its length is 1 so that we highlight at
// least the first character.
Scanner::Location loc(declaration->proxy()->position(),
var_end_pos != kNoSourcePosition
? var_end_pos
: declaration->proxy()->position() + 1);
if (declaration_kind == DeclarationDescriptor::PARAMETER) {
ReportMessageAt(loc, MessageTemplate::kParamDupe);
} else {
ReportMessageAt(loc, MessageTemplate::kVarRedeclaration,
declaration->proxy()->raw_name());
}
return nullptr;
}
if (sloppy_mode_block_scope_function_redefinition) {
++use_counts_[v8::Isolate::kSloppyModeBlockScopedFunctionRedefinition];
}
return variable;
}
Block* Parser::BuildInitializationBlock(
DeclarationParsingResult* parsing_result,
ZoneList<const AstRawString*>* names, bool* ok) {
Block* result = factory()->NewBlock(1, true);
for (auto declaration : parsing_result->declarations) {
DeclareAndInitializeVariables(result, &(parsing_result->descriptor),
&declaration, names, CHECK_OK);
}
return result;
}
Statement* Parser::DeclareFunction(const AstRawString* variable_name,
FunctionLiteral* function, VariableMode mode,
int pos, bool is_sloppy_block_function,
ZoneList<const AstRawString*>* names,
bool* ok) {
VariableProxy* proxy =
factory()->NewVariableProxy(variable_name, NORMAL_VARIABLE);
Declaration* declaration =
factory()->NewFunctionDeclaration(proxy, function, pos);
Declare(declaration, DeclarationDescriptor::NORMAL, mode, kCreatedInitialized,
CHECK_OK);
if (names) names->Add(variable_name, zone());
if (is_sloppy_block_function) {
SloppyBlockFunctionStatement* statement =
factory()->NewSloppyBlockFunctionStatement();
GetDeclarationScope()->DeclareSloppyBlockFunction(variable_name, scope(),
statement);
return statement;
}
return factory()->NewEmptyStatement(kNoSourcePosition);
}
Statement* Parser::DeclareClass(const AstRawString* variable_name,
Expression* value,
ZoneList<const AstRawString*>* names,
int class_token_pos, int end_pos, bool* ok) {
Declaration* decl =
DeclareVariable(variable_name, LET, class_token_pos, CHECK_OK);
decl->proxy()->var()->set_initializer_position(end_pos);
if (names) names->Add(variable_name, zone());
Assignment* assignment = factory()->NewAssignment(Token::INIT, decl->proxy(),
value, class_token_pos);
return IgnoreCompletion(
factory()->NewExpressionStatement(assignment, kNoSourcePosition));
}
Statement* Parser::DeclareNative(const AstRawString* name, int pos, bool* ok) {
// Make sure that the function containing the native declaration
// isn't lazily compiled. The extension structures are only
// accessible while parsing the first time not when reparsing
// because of lazy compilation.
GetClosureScope()->ForceEagerCompilation();
// TODO(1240846): It's weird that native function declarations are
// introduced dynamically when we meet their declarations, whereas
// other functions are set up when entering the surrounding scope.
Declaration* decl = DeclareVariable(name, VAR, pos, CHECK_OK);
NativeFunctionLiteral* lit =
factory()->NewNativeFunctionLiteral(name, extension_, kNoSourcePosition);
return factory()->NewExpressionStatement(
factory()->NewAssignment(Token::INIT, decl->proxy(), lit,
kNoSourcePosition),
pos);
}
ZoneList<const AstRawString*>* Parser::DeclareLabel(
ZoneList<const AstRawString*>* labels, VariableProxy* var, bool* ok) {
DCHECK(IsIdentifier(var));
const AstRawString* label = var->raw_name();
// TODO(1240780): We don't check for redeclaration of labels
// during preparsing since keeping track of the set of active
// labels requires nontrivial changes to the way scopes are
// structured. However, these are probably changes we want to
// make later anyway so we should go back and fix this then.
if (ContainsLabel(labels, label) || TargetStackContainsLabel(label)) {
ReportMessage(MessageTemplate::kLabelRedeclaration, label);
*ok = false;
return nullptr;
}
if (labels == nullptr) {
labels = new (zone()) ZoneList<const AstRawString*>(1, zone());
}
labels->Add(label, zone());
// Remove the "ghost" variable that turned out to be a label
// from the top scope. This way, we don't try to resolve it
// during the scope processing.
scope()->RemoveUnresolved(var);
return labels;
}
bool Parser::ContainsLabel(ZoneList<const AstRawString*>* labels,
const AstRawString* label) {
DCHECK_NOT_NULL(label);
if (labels != nullptr) {
for (int i = labels->length(); i-- > 0;) {
if (labels->at(i) == label) return true;
}
}
return false;
}
Block* Parser::IgnoreCompletion(Statement* statement) {
Block* block = factory()->NewBlock(1, true);
block->statements()->Add(statement, zone());
return block;
}
Expression* Parser::RewriteReturn(Expression* return_value, int pos) {
if (IsDerivedConstructor(function_state_->kind())) {
// For subclass constructors we need to return this in case of undefined;
// other primitive values trigger an exception in the ConstructStub.
//
// return expr;
//
// Is rewritten as:
//
// return (temp = expr) === undefined ? this : temp;
// temp = expr
Variable* temp = NewTemporary(ast_value_factory()->empty_string());
Assignment* assign = factory()->NewAssignment(
Token::ASSIGN, factory()->NewVariableProxy(temp), return_value, pos);
// temp === undefined
Expression* is_undefined = factory()->NewCompareOperation(
Token::EQ_STRICT, assign,
factory()->NewUndefinedLiteral(kNoSourcePosition), pos);
// is_undefined ? this : temp
return_value =
factory()->NewConditional(is_undefined, ThisExpression(pos),
factory()->NewVariableProxy(temp), pos);
}
return return_value;
}
Expression* Parser::RewriteDoExpression(Block* body, int pos, bool* ok) {
Variable* result = NewTemporary(ast_value_factory()->dot_result_string());
DoExpression* expr = factory()->NewDoExpression(body, result, pos);
if (!Rewriter::Rewrite(this, GetClosureScope(), expr, ast_value_factory())) {
*ok = false;
return nullptr;
}
return expr;
}
Statement* Parser::RewriteSwitchStatement(SwitchStatement* switch_statement,
Scope* scope) {
// In order to get the CaseClauses to execute in their own lexical scope,
// but without requiring downstream code to have special scope handling
// code for switch statements, desugar into blocks as follows:
// { // To group the statements--harmless to evaluate Expression in scope
// .tag_variable = Expression;
// { // To give CaseClauses a scope
// switch (.tag_variable) { CaseClause* }
// }
// }
DCHECK_NOT_NULL(scope);
DCHECK(scope->is_block_scope());
DCHECK_GE(switch_statement->position(), scope->start_position());
DCHECK_LT(switch_statement->position(), scope->end_position());
Block* switch_block = factory()->NewBlock(2, false);
Expression* tag = switch_statement->tag();
Variable* tag_variable =
NewTemporary(ast_value_factory()->dot_switch_tag_string());
Assignment* tag_assign = factory()->NewAssignment(
Token::ASSIGN, factory()->NewVariableProxy(tag_variable), tag,
tag->position());
// Wrap with IgnoreCompletion so the tag isn't returned as the completion
// value, in case the switch statements don't have a value.
Statement* tag_statement = IgnoreCompletion(
factory()->NewExpressionStatement(tag_assign, kNoSourcePosition));
switch_block->statements()->Add(tag_statement, zone());
switch_statement->set_tag(factory()->NewVariableProxy(tag_variable));
Block* cases_block = factory()->NewBlock(1, false);
cases_block->statements()->Add(switch_statement, zone());
cases_block->set_scope(scope);
switch_block->statements()->Add(cases_block, zone());
return switch_block;
}
void Parser::RewriteCatchPattern(CatchInfo* catch_info, bool* ok) {
if (catch_info->name == nullptr) {
DCHECK_NOT_NULL(catch_info->pattern);
catch_info->name = ast_value_factory()->dot_catch_string();
}
Variable* catch_variable =
catch_info->scope->DeclareLocal(catch_info->name, VAR);
if (catch_info->pattern != nullptr) {
DeclarationDescriptor descriptor;
descriptor.declaration_kind = DeclarationDescriptor::NORMAL;
descriptor.scope = scope();
descriptor.mode = LET;
descriptor.declaration_pos = catch_info->pattern->position();
descriptor.initialization_pos = catch_info->pattern->position();
// Initializer position for variables declared by the pattern.
const int initializer_position = position();
DeclarationParsingResult::Declaration decl(
catch_info->pattern, initializer_position,
factory()->NewVariableProxy(catch_variable));
catch_info->init_block = factory()->NewBlock(8, true);
DeclareAndInitializeVariables(catch_info->init_block, &descriptor, &decl,
&catch_info->bound_names, ok);
} else {
catch_info->bound_names.Add(catch_info->name, zone());
}
}
void Parser::ValidateCatchBlock(const CatchInfo& catch_info, bool* ok) {
// Check for `catch(e) { let e; }` and similar errors.
Scope* inner_block_scope = catch_info.inner_block->scope();
if (inner_block_scope != nullptr) {
Declaration* decl = inner_block_scope->CheckLexDeclarationsConflictingWith(
catch_info.bound_names);
if (decl != nullptr) {
const AstRawString* name = decl->proxy()->raw_name();
int position = decl->proxy()->position();
Scanner::Location location =
position == kNoSourcePosition
? Scanner::Location::invalid()
: Scanner::Location(position, position + 1);
ReportMessageAt(location, MessageTemplate::kVarRedeclaration, name);
*ok = false;
}
}
}
Statement* Parser::RewriteTryStatement(Block* try_block, Block* catch_block,
const SourceRange& catch_range,
Block* finally_block,
const SourceRange& finally_range,
const CatchInfo& catch_info, int pos) {
// Simplify the AST nodes by converting:
// 'try B0 catch B1 finally B2'
// to:
// 'try { try B0 catch B1 } finally B2'
if (catch_block != nullptr && finally_block != nullptr) {
// If we have both, create an inner try/catch.
DCHECK_NOT_NULL(catch_info.scope);
TryCatchStatement* statement;
statement = factory()->NewTryCatchStatement(try_block, catch_info.scope,
catch_block, kNoSourcePosition);
RecordTryCatchStatementSourceRange(statement, catch_range);
try_block = factory()->NewBlock(1, false);
try_block->statements()->Add(statement, zone());
catch_block = nullptr; // Clear to indicate it's been handled.
}
if (catch_block != nullptr) {
DCHECK_NULL(finally_block);
DCHECK_NOT_NULL(catch_info.scope);
TryCatchStatement* stmt = factory()->NewTryCatchStatement(
try_block, catch_info.scope, catch_block, pos);
RecordTryCatchStatementSourceRange(stmt, catch_range);
return stmt;
} else {
DCHECK_NOT_NULL(finally_block);
TryFinallyStatement* stmt =
factory()->NewTryFinallyStatement(try_block, finally_block, pos);
RecordTryFinallyStatementSourceRange(stmt, finally_range);
return stmt;
}
}
void Parser::ParseAndRewriteGeneratorFunctionBody(int pos, FunctionKind kind,
ZoneList<Statement*>* body,
bool* ok) {
// For ES6 Generators, we just prepend the initial yield.
Expression* initial_yield = BuildInitialYield(pos, kind);
body->Add(factory()->NewExpressionStatement(initial_yield, kNoSourcePosition),
zone());
ParseStatementList(body, Token::RBRACE, ok);
}
void Parser::ParseAndRewriteAsyncGeneratorFunctionBody(
int pos, FunctionKind kind, ZoneList<Statement*>* body, bool* ok) {
// For ES2017 Async Generators, we produce:
//
// try {
// InitialYield;
// ...body...;
// return undefined; // See comment below
// } catch (.catch) {
// %AsyncGeneratorReject(generator, .catch);
// } finally {
// %_GeneratorClose(generator);
// }
//
// - InitialYield yields the actual generator object.
// - Any return statement inside the body will have its argument wrapped
// in an iterator result object with a "done" property set to `true`.
// - If the generator terminates for whatever reason, we must close it.
// Hence the finally clause.
// - BytecodeGenerator performs special handling for ReturnStatements in
// async generator functions, resolving the appropriate Promise with an
// "done" iterator result object containing a Promise-unwrapped value.
DCHECK(IsAsyncGeneratorFunction(kind));
Block* try_block = factory()->NewBlock(3, false);
Expression* initial_yield = BuildInitialYield(pos, kind);
try_block->statements()->Add(
factory()->NewExpressionStatement(initial_yield, kNoSourcePosition),
zone());
ParseStatementList(try_block->statements(), Token::RBRACE, ok);
if (!*ok) return;
// Don't create iterator result for async generators, as the resume methods
// will create it.
Statement* final_return = BuildReturnStatement(
factory()->NewUndefinedLiteral(kNoSourcePosition), kNoSourcePosition);
try_block->statements()->Add(final_return, zone());
// For AsyncGenerators, a top-level catch block will reject the Promise.
Scope* catch_scope = NewHiddenCatchScope();
ZoneList<Expression*>* reject_args =
new (zone()) ZoneList<Expression*>(2, zone());
reject_args->Add(factory()->NewVariableProxy(
function_state_->scope()->generator_object_var()),
zone());
reject_args->Add(factory()->NewVariableProxy(catch_scope->catch_variable()),
zone());
Expression* reject_call = factory()->NewCallRuntime(
Runtime::kInlineAsyncGeneratorReject, reject_args, kNoSourcePosition);
Block* catch_block = IgnoreCompletion(
factory()->NewReturnStatement(reject_call, kNoSourcePosition));
TryStatement* try_catch = factory()->NewTryCatchStatementForAsyncAwait(
try_block, catch_scope, catch_block, kNoSourcePosition);
try_block = factory()->NewBlock(1, false);
try_block->statements()->Add(try_catch, zone());
Block* finally_block = factory()->NewBlock(1, false);
ZoneList<Expression*>* close_args =
new (zone()) ZoneList<Expression*>(1, zone());
VariableProxy* call_proxy = factory()->NewVariableProxy(
function_state_->scope()->generator_object_var());
close_args->Add(call_proxy, zone());
Expression* close_call = factory()->NewCallRuntime(
Runtime::kInlineGeneratorClose, close_args, kNoSourcePosition);
finally_block->statements()->Add(
factory()->NewExpressionStatement(close_call, kNoSourcePosition), zone());
body->Add(factory()->NewTryFinallyStatement(try_block, finally_block,
kNoSourcePosition),
zone());
}
void Parser::DeclareFunctionNameVar(const AstRawString* function_name,
FunctionLiteral::FunctionType function_type,
DeclarationScope* function_scope) {
if (function_type == FunctionLiteral::kNamedExpression &&
function_scope->LookupLocal(function_name) == nullptr) {
DCHECK_EQ(function_scope, scope());
function_scope->DeclareFunctionVar(function_name);
}
}
// [if (IteratorType == kNormal)]
// !%_IsJSReceiver(result = iterator.next()) &&
// %ThrowIteratorResultNotAnObject(result)
// [else if (IteratorType == kAsync)]
// !%_IsJSReceiver(result = Await(iterator.next())) &&
// %ThrowIteratorResultNotAnObject(result)
// [endif]
Expression* Parser::BuildIteratorNextResult(Expression* iterator,
Variable* result, IteratorType type,
int pos) {
Expression* next_literal = factory()->NewStringLiteral(
ast_value_factory()->next_string(), kNoSourcePosition);
Expression* next_property =
factory()->NewProperty(iterator, next_literal, kNoSourcePosition);
ZoneList<Expression*>* next_arguments =
new (zone()) ZoneList<Expression*>(0, zone());
Expression* next_call =
factory()->NewCall(next_property, next_arguments, kNoSourcePosition);
if (type == IteratorType::kAsync) {
next_call = factory()->NewAwait(next_call, pos);
}
Expression* result_proxy = factory()->NewVariableProxy(result);
Expression* left =
factory()->NewAssignment(Token::ASSIGN, result_proxy, next_call, pos);
// %_IsJSReceiver(...)
ZoneList<Expression*>* is_spec_object_args =
new (zone()) ZoneList<Expression*>(1, zone());
is_spec_object_args->Add(left, zone());
Expression* is_spec_object_call = factory()->NewCallRuntime(
Runtime::kInlineIsJSReceiver, is_spec_object_args, pos);
// %ThrowIteratorResultNotAnObject(result)
Expression* result_proxy_again = factory()->NewVariableProxy(result);
ZoneList<Expression*>* throw_arguments =
new (zone()) ZoneList<Expression*>(1, zone());
throw_arguments->Add(result_proxy_again, zone());
Expression* throw_call = factory()->NewCallRuntime(
Runtime::kThrowIteratorResultNotAnObject, throw_arguments, pos);
return factory()->NewBinaryOperation(
Token::AND,
factory()->NewUnaryOperation(Token::NOT, is_spec_object_call, pos),
throw_call, pos);
}
Statement* Parser::InitializeForEachStatement(ForEachStatement* stmt,
Expression* each,
Expression* subject,
Statement* body) {
ForOfStatement* for_of = stmt->AsForOfStatement();
if (for_of != nullptr) {
const bool finalize = true;
return InitializeForOfStatement(for_of, each, subject, body, finalize,
IteratorType::kNormal, each->position());
} else {
if (each->IsArrayLiteral() || each->IsObjectLiteral()) {
Variable* temp = NewTemporary(ast_value_factory()->empty_string());
VariableProxy* temp_proxy = factory()->NewVariableProxy(temp);
Expression* assign_each =
RewriteDestructuringAssignment(factory()->NewAssignment(
Token::ASSIGN, each, temp_proxy, kNoSourcePosition));
auto block = factory()->NewBlock(2, false);
block->statements()->Add(
factory()->NewExpressionStatement(assign_each, kNoSourcePosition),
zone());
block->statements()->Add(body, zone());
body = block;
each = factory()->NewVariableProxy(temp);
}
MarkExpressionAsAssigned(each);
stmt->AsForInStatement()->Initialize(each, subject, body);
}
return stmt;
}
// Special case for legacy for
//
// for (var x = initializer in enumerable) body
//
// An initialization block of the form
//
// {
// x = initializer;
// }
//
// is returned in this case. It has reserved space for two statements,
// so that (later on during parsing), the equivalent of
//
// for (x in enumerable) body
//
// is added as a second statement to it.
Block* Parser::RewriteForVarInLegacy(const ForInfo& for_info) {
const DeclarationParsingResult::Declaration& decl =
for_info.parsing_result.declarations[0];
if (!IsLexicalVariableMode(for_info.parsing_result.descriptor.mode) &&
decl.pattern->IsVariableProxy() && decl.initializer != nullptr) {
++use_counts_[v8::Isolate::kForInInitializer];
const AstRawString* name = decl.pattern->AsVariableProxy()->raw_name();
VariableProxy* single_var = NewUnresolved(name);
Block* init_block = factory()->NewBlock(2, true);
init_block->statements()->Add(
factory()->NewExpressionStatement(
factory()->NewAssignment(Token::ASSIGN, single_var,
decl.initializer, kNoSourcePosition),
kNoSourcePosition),
zone());
return init_block;
}
return nullptr;
}
// Rewrite a for-in/of statement of the form
//
// for (let/const/var x in/of e) b
//
// into
//
// {
// var temp;
// for (temp in/of e) {
// let/const/var x = temp;
// b;
// }
// let x; // for TDZ
// }
void Parser::DesugarBindingInForEachStatement(ForInfo* for_info,
Block** body_block,
Expression** each_variable,
bool* ok) {
DCHECK_EQ(1, for_info->parsing_result.declarations.size());
DeclarationParsingResult::Declaration& decl =
for_info->parsing_result.declarations[0];
Variable* temp = NewTemporary(ast_value_factory()->dot_for_string());
auto each_initialization_block = factory()->NewBlock(1, true);
{
auto descriptor = for_info->parsing_result.descriptor;
descriptor.declaration_pos = kNoSourcePosition;
descriptor.initialization_pos = kNoSourcePosition;
descriptor.scope = scope();
decl.initializer = factory()->NewVariableProxy(temp);
bool is_for_var_of =
for_info->mode == ForEachStatement::ITERATE &&
for_info->parsing_result.descriptor.mode == VariableMode::VAR;
bool collect_names =
IsLexicalVariableMode(for_info->parsing_result.descriptor.mode) ||
is_for_var_of;
DeclareAndInitializeVariables(
each_initialization_block, &descriptor, &decl,
collect_names ? &for_info->bound_names : nullptr, CHECK_OK_VOID);
// Annex B.3.5 prohibits the form
// `try {} catch(e) { for (var e of {}); }`
// So if we are parsing a statement like `for (var ... of ...)`
// we need to walk up the scope chain and look for catch scopes
// which have a simple binding, then compare their binding against
// all of the names declared in the init of the for-of we're
// parsing.
if (is_for_var_of) {
Scope* catch_scope = scope();
while (catch_scope != nullptr && !catch_scope->is_declaration_scope()) {
if (catch_scope->is_catch_scope()) {
auto name = catch_scope->catch_variable()->raw_name();
// If it's a simple binding and the name is declared in the for loop.
if (name != ast_value_factory()->dot_catch_string() &&
for_info->bound_names.Contains(name)) {
ReportMessageAt(for_info->parsing_result.bindings_loc,
MessageTemplate::kVarRedeclaration, name);
*ok = false;
return;
}
}
catch_scope = catch_scope->outer_scope();
}
}
}
*body_block = factory()->NewBlock(3, false);
(*body_block)->statements()->Add(each_initialization_block, zone());
*each_variable = factory()->NewVariableProxy(temp, for_info->position);
}
// Create a TDZ for any lexically-bound names in for in/of statements.
Block* Parser::CreateForEachStatementTDZ(Block* init_block,
const ForInfo& for_info, bool* ok) {
if (IsLexicalVariableMode(for_info.parsing_result.descriptor.mode)) {
DCHECK_NULL(init_block);
init_block = factory()->NewBlock(1, false);
for (int i = 0; i < for_info.bound_names.length(); ++i) {
// TODO(adamk): This needs to be some sort of special
// INTERNAL variable that's invisible to the debugger
// but visible to everything else.
Declaration* tdz_decl = DeclareVariable(for_info.bound_names[i], LET,
kNoSourcePosition, CHECK_OK);
tdz_decl->proxy()->var()->set_initializer_position(position());
}
}
return init_block;
}
Statement* Parser::InitializeForOfStatement(
ForOfStatement* for_of, Expression* each, Expression* iterable,
Statement* body, bool finalize, IteratorType type, int next_result_pos) {
// Create the auxiliary expressions needed for iterating over the iterable,
// and initialize the given ForOfStatement with them.
// If finalize is true, also instrument the loop with code that performs the
// proper ES6 iterator finalization. In that case, the result is not
// immediately a ForOfStatement.
const int nopos = kNoSourcePosition;
auto avfactory = ast_value_factory();
Variable* iterator = NewTemporary(avfactory->dot_iterator_string());
Variable* result = NewTemporary(avfactory->dot_result_string());
Variable* completion = NewTemporary(avfactory->empty_string());
// iterator = GetIterator(iterable, type)
Expression* assign_iterator;
{
assign_iterator = factory()->NewAssignment(
Token::ASSIGN, factory()->NewVariableProxy(iterator),
factory()->NewGetIterator(iterable, type, iterable->position()),
iterable->position());
}
// [if (IteratorType == kNormal)]
// !%_IsJSReceiver(result = iterator.next()) &&
// %ThrowIteratorResultNotAnObject(result)
// [else if (IteratorType == kAsync)]
// !%_IsJSReceiver(result = Await(iterator.next())) &&
// %ThrowIteratorResultNotAnObject(result)
// [endif]
Expression* next_result;
{
Expression* iterator_proxy = factory()->NewVariableProxy(iterator);
next_result =
BuildIteratorNextResult(iterator_proxy, result, type, next_result_pos);
}
// result.done
Expression* result_done;
{
Expression* done_literal = factory()->NewStringLiteral(
ast_value_factory()->done_string(), kNoSourcePosition);
Expression* result_proxy = factory()->NewVariableProxy(result);
result_done =
factory()->NewProperty(result_proxy, done_literal, kNoSourcePosition);
}
// result.value
Expression* result_value;
{
Expression* value_literal =
factory()->NewStringLiteral(avfactory->value_string(), nopos);
Expression* result_proxy = factory()->NewVariableProxy(result);
result_value = factory()->NewProperty(result_proxy, value_literal, nopos);
}
// {{tmp = #result_value, completion = kAbruptCompletion, tmp}}
// Expression* result_value (gets overwritten)
if (finalize) {
Variable* tmp = NewTemporary(avfactory->empty_string());
Expression* save_result = factory()->NewAssignment(
Token::ASSIGN, factory()->NewVariableProxy(tmp), result_value, nopos);
Expression* set_completion_abrupt = factory()->NewAssignment(
Token::ASSIGN, factory()->NewVariableProxy(completion),
factory()->NewSmiLiteral(Parser::kAbruptCompletion, nopos), nopos);
result_value = factory()->NewBinaryOperation(Token::COMMA, save_result,
set_completion_abrupt, nopos);
result_value = factory()->NewBinaryOperation(
Token::COMMA, result_value, factory()->NewVariableProxy(tmp), nopos);
}
// each = #result_value;
Expression* assign_each;
{
assign_each =
factory()->NewAssignment(Token::ASSIGN, each, result_value, nopos);
if (each->IsArrayLiteral() || each->IsObjectLiteral()) {
assign_each = RewriteDestructuringAssignment(assign_each->AsAssignment());
}
}
// {{completion = kNormalCompletion;}}
Statement* set_completion_normal;
if (finalize) {
Expression* proxy = factory()->NewVariableProxy(completion);
Expression* assignment = factory()->NewAssignment(
Token::ASSIGN, proxy,
factory()->NewSmiLiteral(Parser::kNormalCompletion, nopos), nopos);
set_completion_normal =
IgnoreCompletion(factory()->NewExpressionStatement(assignment, nopos));
}
// { #loop-body; #set_completion_normal }
// Statement* body (gets overwritten)
if (finalize) {
Block* block = factory()->NewBlock(2, false);
block->statements()->Add(body, zone());
block->statements()->Add(set_completion_normal, zone());
body = block;
}
for_of->Initialize(body, iterator, assign_iterator, next_result, result_done,
assign_each);
return finalize ? FinalizeForOfStatement(for_of, completion, type, nopos)
: for_of;
}
Statement* Parser::DesugarLexicalBindingsInForStatement(
ForStatement* loop, Statement* init, Expression* cond, Statement* next,
Statement* body, Scope* inner_scope, const ForInfo& for_info, bool* ok) {
// ES6 13.7.4.8 specifies that on each loop iteration the let variables are
// copied into a new environment. Moreover, the "next" statement must be
// evaluated not in the environment of the just completed iteration but in
// that of the upcoming one. We achieve this with the following desugaring.
// Extra care is needed to preserve the completion value of the original loop.
//
// We are given a for statement of the form
//
// labels: for (let/const x = i; cond; next) body
//
// and rewrite it as follows. Here we write {{ ... }} for init-blocks, ie.,
// blocks whose ignore_completion_value_ flag is set.
//
// {
// let/const x = i;
// temp_x = x;
// first = 1;
// undefined;
// outer: for (;;) {
// let/const x = temp_x;
// {{ if (first == 1) {
// first = 0;
// } else {
// next;
// }
// flag = 1;
// if (!cond) break;
// }}
// labels: for (; flag == 1; flag = 0, temp_x = x) {
// body
// }
// {{ if (flag == 1) // Body used break.
// break;
// }}
// }
// }
DCHECK_GT(for_info.bound_names.length(), 0);
ZoneList<Variable*> temps(for_info.bound_names.length(), zone());
Block* outer_block =
factory()->NewBlock(for_info.bound_names.length() + 4, false);
// Add statement: let/const x = i.
outer_block->statements()->Add(init, zone());
const AstRawString* temp_name = ast_value_factory()->dot_for_string();
// For each lexical variable x:
// make statement: temp_x = x.
for (int i = 0; i < for_info.bound_names.length(); i++) {
VariableProxy* proxy = NewUnresolved(for_info.bound_names[i]);
Variable* temp = NewTemporary(temp_name);
VariableProxy* temp_proxy = factory()->NewVariableProxy(temp);
Assignment* assignment = factory()->NewAssignment(Token::ASSIGN, temp_proxy,
proxy, kNoSourcePosition);
Statement* assignment_statement =
factory()->NewExpressionStatement(assignment, kNoSourcePosition);
outer_block->statements()->Add(assignment_statement, zone());
temps.Add(temp, zone());
}
Variable* first = nullptr;
// Make statement: first = 1.
if (next) {
first = NewTemporary(temp_name);
VariableProxy* first_proxy = factory()->NewVariableProxy(first);
Expression* const1 = factory()->NewSmiLiteral(1, kNoSourcePosition);
Assignment* assignment = factory()->NewAssignment(
Token::ASSIGN, first_proxy, const1, kNoSourcePosition);
Statement* assignment_statement =
factory()->NewExpressionStatement(assignment, kNoSourcePosition);
outer_block->statements()->Add(assignment_statement, zone());
}
// make statement: undefined;
outer_block->statements()->Add(
factory()->NewExpressionStatement(
factory()->NewUndefinedLiteral(kNoSourcePosition), kNoSourcePosition),
zone());
// Make statement: outer: for (;;)
// Note that we don't actually create the label, or set this loop up as an
// explicit break target, instead handing it directly to those nodes that
// need to know about it. This should be safe because we don't run any code
// in this function that looks up break targets.
ForStatement* outer_loop =
factory()->NewForStatement(nullptr, kNoSourcePosition);
outer_block->statements()->Add(outer_loop, zone());
outer_block->set_scope(scope());
Block* inner_block = factory()->NewBlock(3, false);
{
BlockState block_state(&scope_, inner_scope);
Block* ignore_completion_block =
factory()->NewBlock(for_info.bound_names.length() + 3, true);
ZoneList<Variable*> inner_vars(for_info.bound_names.length(), zone());
// For each let variable x:
// make statement: let/const x = temp_x.
for (int i = 0; i < for_info.bound_names.length(); i++) {
Declaration* decl = DeclareVariable(
for_info.bound_names[i], for_info.parsing_result.descriptor.mode,
kNoSourcePosition, CHECK_OK);
inner_vars.Add(decl->proxy()->var(), zone());
VariableProxy* temp_proxy = factory()->NewVariableProxy(temps.at(i));
Assignment* assignment = factory()->NewAssignment(
Token::INIT, decl->proxy(), temp_proxy, kNoSourcePosition);
Statement* assignment_statement =
factory()->NewExpressionStatement(assignment, kNoSourcePosition);
int declaration_pos = for_info.parsing_result.descriptor.declaration_pos;
DCHECK_NE(declaration_pos, kNoSourcePosition);
decl->proxy()->var()->set_initializer_position(declaration_pos);
ignore_completion_block->statements()->Add(assignment_statement, zone());
}
// Make statement: if (first == 1) { first = 0; } else { next; }
if (next) {
DCHECK(first);
Expression* compare = nullptr;
// Make compare expression: first == 1.
{
Expression* const1 = factory()->NewSmiLiteral(1, kNoSourcePosition);
VariableProxy* first_proxy = factory()->NewVariableProxy(first);
compare = factory()->NewCompareOperation(Token::EQ, first_proxy, const1,
kNoSourcePosition);
}
Statement* clear_first = nullptr;
// Make statement: first = 0.
{
VariableProxy* first_proxy = factory()->NewVariableProxy(first);
Expression* const0 = factory()->NewSmiLiteral(0, kNoSourcePosition);
Assignment* assignment = factory()->NewAssignment(
Token::ASSIGN, first_proxy, const0, kNoSourcePosition);
clear_first =
factory()->NewExpressionStatement(assignment, kNoSourcePosition);
}
Statement* clear_first_or_next = factory()->NewIfStatement(
compare, clear_first, next, kNoSourcePosition);
ignore_completion_block->statements()->Add(clear_first_or_next, zone());
}
Variable* flag = NewTemporary(temp_name);
// Make statement: flag = 1.
{
VariableProxy* flag_proxy = factory()->NewVariableProxy(flag);
Expression* const1 = factory()->NewSmiLiteral(1, kNoSourcePosition);
Assignment* assignment = factory()->NewAssignment(
Token::ASSIGN, flag_proxy, const1, kNoSourcePosition);
Statement* assignment_statement =
factory()->NewExpressionStatement(assignment, kNoSourcePosition);
ignore_completion_block->statements()->Add(assignment_statement, zone());
}
// Make statement: if (!cond) break.
if (cond) {
Statement* stop =
factory()->NewBreakStatement(outer_loop, kNoSourcePosition);
Statement* noop = factory()->NewEmptyStatement(kNoSourcePosition);
ignore_completion_block->statements()->Add(
factory()->NewIfStatement(cond, noop, stop, cond->position()),
zone());
}
inner_block->statements()->Add(ignore_completion_block, zone());
// Make cond expression for main loop: flag == 1.
Expression* flag_cond = nullptr;
{
Expression* const1 = factory()->NewSmiLiteral(1, kNoSourcePosition);
VariableProxy* flag_proxy = factory()->NewVariableProxy(flag);
flag_cond = factory()->NewCompareOperation(Token::EQ, flag_proxy, const1,
kNoSourcePosition);
}
// Create chain of expressions "flag = 0, temp_x = x, ..."
Statement* compound_next_statement = nullptr;
{
Expression* compound_next = nullptr;
// Make expression: flag = 0.
{
VariableProxy* flag_proxy = factory()->NewVariableProxy(flag);
Expression* const0 = factory()->NewSmiLiteral(0, kNoSourcePosition);
compound_next = factory()->NewAssignment(Token::ASSIGN, flag_proxy,
const0, kNoSourcePosition);
}
// Make the comma-separated list of temp_x = x assignments.
int inner_var_proxy_pos = scanner()->location().beg_pos;
for (int i = 0; i < for_info.bound_names.length(); i++) {
VariableProxy* temp_proxy = factory()->NewVariableProxy(temps.at(i));
VariableProxy* proxy =
factory()->NewVariableProxy(inner_vars.at(i), inner_var_proxy_pos);
Assignment* assignment = factory()->NewAssignment(
Token::ASSIGN, temp_proxy, proxy, kNoSourcePosition);
compound_next = factory()->NewBinaryOperation(
Token::COMMA, compound_next, assignment, kNoSourcePosition);
}
compound_next_statement =
factory()->NewExpressionStatement(compound_next, kNoSourcePosition);
}
// Make statement: labels: for (; flag == 1; flag = 0, temp_x = x)
// Note that we re-use the original loop node, which retains its labels
// and ensures that any break or continue statements in body point to
// the right place.
loop->Initialize(nullptr, flag_cond, compound_next_statement, body);
inner_block->statements()->Add(loop, zone());
// Make statement: {{if (flag == 1) break;}}
{
Expression* compare = nullptr;
// Make compare expresion: flag == 1.
{
Expression* const1 = factory()->NewSmiLiteral(1, kNoSourcePosition);
VariableProxy* flag_proxy = factory()->NewVariableProxy(flag);
compare = factory()->NewCompareOperation(Token::EQ, flag_proxy, const1,
kNoSourcePosition);
}
Statement* stop =
factory()->NewBreakStatement(outer_loop, kNoSourcePosition);
Statement* empty = factory()->NewEmptyStatement(kNoSourcePosition);
Statement* if_flag_break =
factory()->NewIfStatement(compare, stop, empty, kNoSourcePosition);
inner_block->statements()->Add(IgnoreCompletion(if_flag_break), zone());
}
inner_block->set_scope(inner_scope);
}
outer_loop->Initialize(nullptr, nullptr, nullptr, inner_block);
return outer_block;
}
void Parser::AddArrowFunctionFormalParameters(
ParserFormalParameters* parameters, Expression* expr, int end_pos,
bool* ok) {
// ArrowFunctionFormals ::
// Nary(Token::COMMA, VariableProxy*, Tail)
// Binary(Token::COMMA, NonTailArrowFunctionFormals, Tail)
// Tail
// NonTailArrowFunctionFormals ::
// Binary(Token::COMMA, NonTailArrowFunctionFormals, VariableProxy)
// VariableProxy
// Tail ::
// VariableProxy
// Spread(VariableProxy)
//
// We need to visit the parameters in left-to-right order
//
// For the Nary case, we simply visit the parameters in a loop.
if (expr->IsNaryOperation()) {
NaryOperation* nary = expr->AsNaryOperation();
// The classifier has already run, so we know that the expression is a valid
// arrow function formals production.
DCHECK_EQ(nary->op(), Token::COMMA);
// Each op position is the end position of the *previous* expr, with the
// second (i.e. first "subsequent") op position being the end position of
// the first child expression.
Expression* next = nary->first();
for (size_t i = 0; i < nary->subsequent_length(); ++i) {
AddArrowFunctionFormalParameters(
parameters, next, nary->subsequent_op_position(i), CHECK_OK_VOID);
next = nary->subsequent(i);
}
AddArrowFunctionFormalParameters(parameters, next, end_pos, CHECK_OK_VOID);
return;
}
// For the binary case, we recurse on the left-hand side of binary comma
// expressions.
if (expr->IsBinaryOperation()) {
BinaryOperation* binop = expr->AsBinaryOperation();
// The classifier has already run, so we know that the expression is a valid
// arrow function formals production.
DCHECK_EQ(binop->op(), Token::COMMA);
Expression* left = binop->left();
Expression* right = binop->right();
int comma_pos = binop->position();
AddArrowFunctionFormalParameters(parameters, left, comma_pos,
CHECK_OK_VOID);
// LHS of comma expression should be unparenthesized.
expr = right;
}
// Only the right-most expression may be a rest parameter.
DCHECK(!parameters->has_rest);
bool is_rest = expr->IsSpread();
if (is_rest) {
expr = expr->AsSpread()->expression();
parameters->has_rest = true;
}
DCHECK_IMPLIES(parameters->is_simple, !is_rest);
DCHECK_IMPLIES(parameters->is_simple, expr->IsVariableProxy());
Expression* initializer = nullptr;
if (expr->IsAssignment()) {
if (expr->IsRewritableExpression()) {
// This expression was parsed as a possible destructuring assignment.
// Mark it as already-rewritten to avoid an unnecessary visit later.
expr->AsRewritableExpression()->set_rewritten();
}
Assignment* assignment = expr->AsAssignment();
DCHECK(!assignment->IsCompoundAssignment());
initializer = assignment->value();
expr = assignment->target();
}
AddFormalParameter(parameters, expr, initializer,
end_pos, is_rest);
}
void Parser::DeclareArrowFunctionFormalParameters(
ParserFormalParameters* parameters, Expression* expr,
const Scanner::Location& params_loc, Scanner::Location* duplicate_loc,
bool* ok) {
if (expr->IsEmptyParentheses()) return;
AddArrowFunctionFormalParameters(parameters, expr, params_loc.end_pos,
CHECK_OK_VOID);
if (parameters->arity > Code::kMaxArguments) {
ReportMessageAt(params_loc, MessageTemplate::kMalformedArrowFunParamList);
*ok = false;
return;
}
bool has_duplicate = false;
DeclareFormalParameters(parameters->scope, parameters->params,
parameters->is_simple, &has_duplicate);
if (has_duplicate) {
*duplicate_loc = scanner()->location();
}
DCHECK_EQ(parameters->is_simple, parameters->scope->has_simple_parameters());
}
void Parser::PrepareGeneratorVariables() {
// The code produced for generators relies on forced context allocation of
// parameters (it does not restore the frame's parameters upon resume).
function_state_->scope()->ForceContextAllocationForParameters();
// Calling a generator returns a generator object. That object is stored
// in a temporary variable, a definition that is used by "yield"
// expressions.
function_state_->scope()->DeclareGeneratorObjectVar(
ast_value_factory()->dot_generator_object_string());
}
FunctionLiteral* Parser::ParseFunctionLiteral(
const AstRawString* function_name, Scanner::Location function_name_location,
FunctionNameValidity function_name_validity, FunctionKind kind,
int function_token_pos, FunctionLiteral::FunctionType function_type,
LanguageMode language_mode, bool* ok) {
// Function ::
// '(' FormalParameterList? ')' '{' FunctionBody '}'
//
// Getter ::
// '(' ')' '{' FunctionBody '}'
//
// Setter ::
// '(' PropertySetParameterList ')' '{' FunctionBody '}'
int pos = function_token_pos == kNoSourcePosition ? peek_position()
: function_token_pos;
// Anonymous functions were passed either the empty symbol or a null
// handle as the function name. Remember if we were passed a non-empty
// handle to decide whether to invoke function name inference.
bool should_infer_name = function_name == nullptr;
// We want a non-null handle as the function name by default. We will handle
// the "function does not have a shared name" case later.
if (should_infer_name) {
function_name = ast_value_factory()->empty_string();
}
FunctionLiteral::EagerCompileHint eager_compile_hint =
function_state_->next_function_is_likely_called()
? FunctionLiteral::kShouldEagerCompile
: default_eager_compile_hint();
// Determine if the function can be parsed lazily. Lazy parsing is
// different from lazy compilation; we need to parse more eagerly than we
// compile.
// We can only parse lazily if we also compile lazily. The heuristics for lazy
// compilation are:
// - It must not have been prohibited by the caller to Parse (some callers
// need a full AST).
// - The outer scope must allow lazy compilation of inner functions.
// - The function mustn't be a function expression with an open parenthesis
// before; we consider that a hint that the function will be called
// immediately, and it would be a waste of time to make it lazily
// compiled.
// These are all things we can know at this point, without looking at the
// function itself.
// We separate between lazy parsing top level functions and lazy parsing inner
// functions, because the latter needs to do more work. In particular, we need
// to track unresolved variables to distinguish between these cases:
// (function foo() {
// bar = function() { return 1; }
// })();
// and
// (function foo() {
// var a = 1;
// bar = function() { return a; }
// })();
// Now foo will be parsed eagerly and compiled eagerly (optimization: assume
// parenthesis before the function means that it will be called
// immediately). bar can be parsed lazily, but we need to parse it in a mode
// that tracks unresolved variables.
DCHECK_IMPLIES(parse_lazily(), FLAG_lazy);
DCHECK_IMPLIES(parse_lazily(), allow_lazy_);
DCHECK_IMPLIES(parse_lazily(), extension_ == nullptr);
const bool is_lazy =
eager_compile_hint == FunctionLiteral::kShouldLazyCompile;
const bool is_top_level = AllowsLazyParsingWithoutUnresolvedVariables();
const bool is_lazy_top_level_function = is_lazy && is_top_level;
const bool is_lazy_inner_function = is_lazy && !is_top_level;
const bool is_expression =
function_type == FunctionLiteral::kAnonymousExpression ||
function_type == FunctionLiteral::kNamedExpression;
RuntimeCallTimerScope runtime_timer(
runtime_call_stats_,
parsing_on_main_thread_
? RuntimeCallCounterId::kParseFunctionLiteral
: RuntimeCallCounterId::kParseBackgroundFunctionLiteral);
base::ElapsedTimer timer;
if (V8_UNLIKELY(FLAG_log_function_events)) timer.Start();
// Determine whether we can still lazy parse the inner function.
// The preconditions are:
// - Lazy compilation has to be enabled.
// - Neither V8 natives nor native function declarations can be allowed,
// since parsing one would retroactively force the function to be
// eagerly compiled.
// - The invoker of this parser can't depend on the AST being eagerly
// built (either because the function is about to be compiled, or
// because the AST is going to be inspected for some reason).
// - Because of the above, we can't be attempting to parse a
// FunctionExpression; even without enclosing parentheses it might be
// immediately invoked.
// - The function literal shouldn't be hinted to eagerly compile.
// Inner functions will be parsed using a temporary Zone. After parsing, we
// will migrate unresolved variable into a Scope in the main Zone.
const bool should_preparse_inner =
parse_lazily() && FLAG_lazy_inner_functions && is_lazy_inner_function &&
(!is_expression || FLAG_aggressive_lazy_inner_functions);
// This may be modified later to reflect preparsing decision taken
bool should_preparse =
(parse_lazily() && is_lazy_top_level_function) || should_preparse_inner;
ZoneList<Statement*>* body = nullptr;
int expected_property_count = -1;
int num_parameters = -1;
int function_length = -1;
bool has_duplicate_parameters = false;
int function_literal_id = GetNextFunctionLiteralId();
ProducedPreParsedScopeData* produced_preparsed_scope_data = nullptr;
Zone* outer_zone = zone();
DeclarationScope* scope;
{
// Temporary zones can nest. When we migrate free variables (see below), we
// need to recreate them in the previous Zone.
AstNodeFactory previous_zone_ast_node_factory(ast_value_factory(), zone());
// Open a new zone scope, which sets our AstNodeFactory to allocate in the
// new temporary zone if the preconditions are satisfied, and ensures that
// the previous zone is always restored after parsing the body. To be able
// to do scope analysis correctly after full parsing, we migrate needed
// information when the function is parsed.
Zone temp_zone(zone()->allocator(), ZONE_NAME);
DiscardableZoneScope zone_scope(this, &temp_zone, should_preparse);
// This Scope lives in the main zone. We'll migrate data into that zone
// later.
scope = NewFunctionScope(kind, outer_zone);
SetLanguageMode(scope, language_mode);
#ifdef DEBUG
scope->SetScopeName(function_name);
if (should_preparse) scope->set_needs_migration();
#endif
Expect(Token::LPAREN, CHECK_OK);
scope->set_start_position(scanner()->location().beg_pos);
// Eager or lazy parse? If is_lazy_top_level_function, we'll parse
// lazily. We'll call SkipFunction, which may decide to
// abort lazy parsing if it suspects that wasn't a good idea. If so (in
// which case the parser is expected to have backtracked), or if we didn't
// try to lazy parse in the first place, we'll have to parse eagerly.
if (should_preparse) {
DCHECK(parse_lazily());
DCHECK(is_lazy_top_level_function || is_lazy_inner_function);
Scanner::BookmarkScope bookmark(scanner());
bookmark.Set();
LazyParsingResult result = SkipFunction(
function_name, kind, function_type, scope, &num_parameters,
&produced_preparsed_scope_data, is_lazy_inner_function,
is_lazy_top_level_function, CHECK_OK);
if (result == kLazyParsingAborted) {
DCHECK(is_lazy_top_level_function);
bookmark.Apply();
// This is probably an initialization function. Inform the compiler it
// should also eager-compile this function.
eager_compile_hint = FunctionLiteral::kShouldEagerCompile;
scope->ResetAfterPreparsing(ast_value_factory(), true);
zone_scope.Reset();
// Trigger eager (re-)parsing, just below this block.
should_preparse = false;
}
}
if (should_preparse) {
scope->AnalyzePartially(&previous_zone_ast_node_factory);
} else {
body = ParseFunction(function_name, pos, kind, function_type, scope,
&num_parameters, &function_length,
&has_duplicate_parameters, &expected_property_count,
CHECK_OK);
}
DCHECK_EQ(should_preparse, temp_zoned_);
if (V8_UNLIKELY(FLAG_log_function_events)) {
double ms = timer.Elapsed().InMillisecondsF();
const char* event_name = should_preparse
? (is_top_level ? "preparse-no-resolution"
: "preparse-resolution")
: "full-parse";
logger_->FunctionEvent(
event_name, nullptr, script_id(), ms, scope->start_position(),
scope->end_position(),
reinterpret_cast<const char*>(function_name->raw_data()),
function_name->byte_length());
}
if (V8_UNLIKELY(FLAG_runtime_stats)) {
if (should_preparse) {
RuntimeCallCounterId counter_id =
parsing_on_main_thread_
? RuntimeCallCounterId::kPreParseWithVariableResolution
: RuntimeCallCounterId::
kPreParseBackgroundWithVariableResolution;
if (is_top_level) {
counter_id = parsing_on_main_thread_
? RuntimeCallCounterId::kPreParseNoVariableResolution
: RuntimeCallCounterId::
kPreParseBackgroundNoVariableResolution;
}
if (runtime_call_stats_) {
runtime_call_stats_->CorrectCurrentCounterId(counter_id);
}
}
}
// Validate function name. We can do this only after parsing the function,
// since the function can declare itself strict.
language_mode = scope->language_mode();
CheckFunctionName(language_mode, function_name, function_name_validity,
function_name_location, CHECK_OK);
if (is_strict(language_mode)) {
CheckStrictOctalLiteral(scope->start_position(), scope->end_position(),
CHECK_OK);
}
CheckConflictingVarDeclarations(scope, CHECK_OK);
} // DiscardableZoneScope goes out of scope.
FunctionLiteral::ParameterFlag duplicate_parameters =
has_duplicate_parameters ? FunctionLiteral::kHasDuplicateParameters
: FunctionLiteral::kNoDuplicateParameters;
// Note that the FunctionLiteral needs to be created in the main Zone again.
FunctionLiteral* function_literal = factory()->NewFunctionLiteral(
function_name, scope, body, expected_property_count, num_parameters,
function_length, duplicate_parameters, function_type, eager_compile_hint,
pos, true, function_literal_id, produced_preparsed_scope_data);
function_literal->set_function_token_position(function_token_pos);
if (should_infer_name) {
DCHECK_NOT_NULL(fni_);
fni_->AddFunction(function_literal);
}
return function_literal;
}
Parser::LazyParsingResult Parser::SkipFunction(
const AstRawString* function_name, FunctionKind kind,
FunctionLiteral::FunctionType function_type,
DeclarationScope* function_scope, int* num_parameters,
ProducedPreParsedScopeData** produced_preparsed_scope_data,
bool is_inner_function, bool may_abort, bool* ok) {
FunctionState function_state(&function_state_, &scope_, function_scope);
DCHECK_NE(kNoSourcePosition, function_scope->start_position());
DCHECK_EQ(kNoSourcePosition, parameters_end_pos_);
if (produce_cached_parse_data()) CHECK(log_);
DCHECK_IMPLIES(IsArrowFunction(kind),
scanner()->current_token() == Token::ARROW);
// Inner functions are not part of the cached data.
if (!is_inner_function && consume_cached_parse_data() &&
!cached_parse_data_->rejected()) {
// If we have cached data, we use it to skip parsing the function. The data
// contains the information we need to construct the lazy function.
FunctionEntry entry =
cached_parse_data_->GetFunctionEntry(function_scope->start_position());
// Check that cached data is valid. If not, mark it as invalid (the embedder
// handles it). Note that end position greater than end of stream is safe,
// and hard to check.
if (entry.is_valid() &&
entry.end_pos() > function_scope->start_position()) {
total_preparse_skipped_ += entry.end_pos() - position();
function_scope->set_end_position(entry.end_pos());
scanner()->SeekForward(entry.end_pos() - 1);
Expect(Token::RBRACE, CHECK_OK_VALUE(kLazyParsingComplete));
*num_parameters = entry.num_parameters();
SetLanguageMode(function_scope, entry.language_mode());
if (entry.uses_super_property())
function_scope->RecordSuperPropertyUsage();
SkipFunctionLiterals(entry.num_inner_functions());
return kLazyParsingComplete;
}
cached_parse_data_->Reject();
}
// FIXME(marja): There are 3 ways to skip functions now. Unify them.
DCHECK_NOT_NULL(consumed_preparsed_scope_data_);
if (consumed_preparsed_scope_data_->HasData()) {
DCHECK(FLAG_preparser_scope_analysis);
int end_position;
LanguageMode language_mode;
int num_inner_functions;
bool uses_super_property;
*produced_preparsed_scope_data =
consumed_preparsed_scope_data_->GetDataForSkippableFunction(
main_zone(), function_scope->start_position(), &end_position,
num_parameters, &num_inner_functions, &uses_super_property,
&language_mode);
function_scope->outer_scope()->SetMustUsePreParsedScopeData();
function_scope->set_is_skipped_function(true);
function_scope->set_end_position(end_position);
scanner()->SeekForward(end_position - 1);
Expect(Token::RBRACE, CHECK_OK_VALUE(kLazyParsingComplete));
SetLanguageMode(function_scope, language_mode);
if (uses_super_property) {
function_scope->RecordSuperPropertyUsage();
}
SkipFunctionLiterals(num_inner_functions);
return kLazyParsingComplete;
}
// With no cached data, we partially parse the function, without building an
// AST. This gathers the data needed to build a lazy function.
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"), "V8.PreParse");
// Aborting inner function preparsing would leave scopes in an inconsistent
// state; we don't parse inner functions in the abortable mode anyway.
DCHECK(!is_inner_function || !may_abort);
PreParser::PreParseResult result = reusable_preparser()->PreParseFunction(
function_name, kind, function_type, function_scope, is_inner_function,
may_abort, use_counts_, produced_preparsed_scope_data, this->script_id());
// Return immediately if pre-parser decided to abort parsing.
if (result == PreParser::kPreParseAbort) return kLazyParsingAborted;
if (result == PreParser::kPreParseStackOverflow) {
// Propagate stack overflow.
set_stack_overflow();
*ok = false;
return kLazyParsingComplete;
}
if (pending_error_handler()->has_pending_error()) {
*ok = false;
return kLazyParsingComplete;
}
PreParserLogger* logger = reusable_preparser()->logger();
function_scope->set_end_position(logger->end());
Expect(Token::RBRACE, CHECK_OK_VALUE(kLazyParsingComplete));
total_preparse_skipped_ +=
function_scope->end_position() - function_scope->start_position();
*num_parameters = logger->num_parameters();
SkipFunctionLiterals(logger->num_inner_functions());
if (!is_inner_function && produce_cached_parse_data()) {
DCHECK(log_);
log_->LogFunction(function_scope->start_position(),
function_scope->end_position(), *num_parameters,
language_mode(), function_scope->NeedsHomeObject(),
logger->num_inner_functions());
}
return kLazyParsingComplete;
}
Statement* Parser::BuildAssertIsCoercible(Variable* var,
ObjectLiteral* pattern) {
// if (var === null || var === undefined)
// throw /* type error kNonCoercible) */;
auto source_position = pattern->position();
const AstRawString* property = ast_value_factory()->empty_string();
MessageTemplate::Template msg = MessageTemplate::kNonCoercible;
for (ObjectLiteralProperty* literal_property : *pattern->properties()) {
Expression* key = literal_property->key();
if (key->IsPropertyName()) {
property = key->AsLiteral()->AsRawPropertyName();
msg = MessageTemplate::kNonCoercibleWithProperty;
source_position = key->position();
break;
}
}
Expression* condition = factory()->NewBinaryOperation(
Token::OR,
factory()->NewCompareOperation(
Token::EQ_STRICT, factory()->NewVariableProxy(var),
factory()->NewUndefinedLiteral(kNoSourcePosition), kNoSourcePosition),
factory()->NewCompareOperation(
Token::EQ_STRICT, factory()->NewVariableProxy(var),
factory()->NewNullLiteral(kNoSourcePosition), kNoSourcePosition),
kNoSourcePosition);
Expression* throw_type_error =
NewThrowTypeError(msg, property, source_position);
IfStatement* if_statement = factory()->NewIfStatement(
condition,
factory()->NewExpressionStatement(throw_type_error, kNoSourcePosition),
factory()->NewEmptyStatement(kNoSourcePosition), kNoSourcePosition);
return if_statement;
}
class InitializerRewriter final
: public AstTraversalVisitor<InitializerRewriter> {
public:
InitializerRewriter(uintptr_t stack_limit, Expression* root, Parser* parser)
: AstTraversalVisitor(stack_limit, root), parser_(parser) {}
private:
// This is required so that the overriden Visit* methods can be
// called by the base class (template).
friend class AstTraversalVisitor<InitializerRewriter>;
// Just rewrite destructuring assignments wrapped in RewritableExpressions.
void VisitRewritableExpression(RewritableExpression* to_rewrite) {
if (to_rewrite->is_rewritten()) return;
parser_->RewriteDestructuringAssignment(to_rewrite);
AstTraversalVisitor::VisitRewritableExpression(to_rewrite);
}
// Code in function literals does not need to be eagerly rewritten, it will be
// rewritten when scheduled.
void VisitFunctionLiteral(FunctionLiteral* expr) {}
Parser* parser_;
};
void Parser::RewriteParameterInitializer(Expression* expr) {
InitializerRewriter rewriter(stack_limit_, expr, this);
rewriter.Run();
}
Block* Parser::BuildParameterInitializationBlock(
const ParserFormalParameters& parameters, bool* ok) {
DCHECK(!parameters.is_simple);
DCHECK(scope()->is_function_scope());
DCHECK_EQ(scope(), parameters.scope);
Block* init_block = factory()->NewBlock(1, true);
int index = 0;
for (auto parameter : parameters.params) {
DeclarationDescriptor descriptor;
descriptor.declaration_kind = DeclarationDescriptor::PARAMETER;
descriptor.scope = scope();
descriptor.mode = LET;
descriptor.declaration_pos = parameter->pattern->position();
// The position that will be used by the AssignmentExpression
// which copies from the temp parameter to the pattern.
//
// TODO(adamk): Should this be kNoSourcePosition, since
// it's just copying from a temp var to the real param var?
descriptor.initialization_pos = parameter->pattern->position();
Expression* initial_value =
factory()->NewVariableProxy(parameters.scope->parameter(index));
if (parameter->initializer != nullptr) {
// IS_UNDEFINED($param) ? initializer : $param
// Ensure initializer is rewritten
RewriteParameterInitializer(parameter->initializer);
auto condition = factory()->NewCompareOperation(
Token::EQ_STRICT,
factory()->NewVariableProxy(parameters.scope->parameter(index)),
factory()->NewUndefinedLiteral(kNoSourcePosition), kNoSourcePosition);
initial_value = factory()->NewConditional(
condition, parameter->initializer, initial_value, kNoSourcePosition);
descriptor.initialization_pos = parameter->initializer->position();
}
Scope* param_scope = scope();
Block* param_block = init_block;
if (!parameter->is_simple() &&
scope()->AsDeclarationScope()->calls_sloppy_eval()) {
param_scope = NewVarblockScope();
param_scope->set_start_position(descriptor.initialization_pos);
param_scope->set_end_position(parameter->initializer_end_position);
param_scope->RecordEvalCall();
param_block = factory()->NewBlock(8, true);
param_block->set_scope(param_scope);
// Pass the appropriate scope in so that PatternRewriter can appropriately
// rewrite inner initializers of the pattern to param_scope
descriptor.scope = param_scope;
// Rewrite the outer initializer to point to param_scope
ReparentExpressionScope(stack_limit(), initial_value, param_scope);
}
BlockState block_state(&scope_, param_scope);
DeclarationParsingResult::Declaration decl(
parameter->pattern, parameter->initializer_end_position, initial_value);
DeclareAndInitializeVariables(param_block, &descriptor, &decl, nullptr,
CHECK_OK);
if (param_block != init_block) {
param_scope = param_scope->FinalizeBlockScope();
if (param_scope != nullptr) {
CheckConflictingVarDeclarations(param_scope, CHECK_OK);
}
init_block->statements()->Add(param_block, zone());
}
++index;
}
return init_block;
}
Scope* Parser::NewHiddenCatchScope() {
Scope* catch_scope = NewScopeWithParent(scope(), CATCH_SCOPE);
catch_scope->DeclareLocal(ast_value_factory()->dot_catch_string(), VAR);
catch_scope->set_is_hidden();
return catch_scope;
}
Block* Parser::BuildRejectPromiseOnException(Block* inner_block) {
// .promise = %AsyncFunctionPromiseCreate();
// try {
// <inner_block>
// } catch (.catch) {
// %RejectPromise(.promise, .catch);
// return .promise;
// } finally {
// %AsyncFunctionPromiseRelease(.promise);
// }
Block* result = factory()->NewBlock(2, true);
// .promise = %AsyncFunctionPromiseCreate();
Statement* set_promise;
{
Expression* create_promise = factory()->NewCallRuntime(
Context::ASYNC_FUNCTION_PROMISE_CREATE_INDEX,
new (zone()) ZoneList<Expression*>(0, zone()), kNoSourcePosition);
Assignment* assign_promise = factory()->NewAssignment(
Token::ASSIGN, factory()->NewVariableProxy(PromiseVariable()),
create_promise, kNoSourcePosition);
set_promise =
factory()->NewExpressionStatement(assign_promise, kNoSourcePosition);
}
result->statements()->Add(set_promise, zone());
// catch (.catch) { return %RejectPromise(.promise, .catch), .promise }
Scope* catch_scope = NewHiddenCatchScope();
Expression* promise_reject = BuildRejectPromise(
factory()->NewVariableProxy(catch_scope->catch_variable()),
kNoSourcePosition);
Block* catch_block = IgnoreCompletion(
factory()->NewReturnStatement(promise_reject, kNoSourcePosition));
TryStatement* try_catch_statement =
factory()->NewTryCatchStatementForAsyncAwait(
inner_block, catch_scope, catch_block, kNoSourcePosition);
// There is no TryCatchFinally node, so wrap it in an outer try/finally
Block* outer_try_block = IgnoreCompletion(try_catch_statement);
// finally { %AsyncFunctionPromiseRelease(.promise) }
Block* finally_block;
{
ZoneList<Expression*>* args = new (zone()) ZoneList<Expression*>(1, zone());
args->Add(factory()->NewVariableProxy(PromiseVariable()), zone());
Expression* call_promise_release = factory()->NewCallRuntime(
Context::ASYNC_FUNCTION_PROMISE_RELEASE_INDEX, args, kNoSourcePosition);
Statement* promise_release = factory()->NewExpressionStatement(
call_promise_release, kNoSourcePosition);
finally_block = IgnoreCompletion(promise_release);
}
Statement* try_finally_statement = factory()->NewTryFinallyStatement(
outer_try_block, finally_block, kNoSourcePosition);
result->statements()->Add(try_finally_statement, zone());
return result;
}
Expression* Parser::BuildResolvePromise(Expression* value, int pos) {
// %ResolvePromise(.promise, value), .promise
ZoneList<Expression*>* args = new (zone()) ZoneList<Expression*>(2, zone());
args->Add(factory()->NewVariableProxy(PromiseVariable()), zone());
args->Add(value, zone());
Expression* call_runtime =
factory()->NewCallRuntime(Context::PROMISE_RESOLVE_INDEX, args, pos);
return factory()->NewBinaryOperation(
Token::COMMA, call_runtime,
factory()->NewVariableProxy(PromiseVariable()), pos);
}
Expression* Parser::BuildRejectPromise(Expression* value, int pos) {
// %promise_internal_reject(.promise, value, false), .promise
// Disables the additional debug event for the rejection since a debug event
// already happened for the exception that got us here.
ZoneList<Expression*>* args = new (zone()) ZoneList<Expression*>(3, zone());
args->Add(factory()->NewVariableProxy(PromiseVariable()), zone());
args->Add(value, zone());
args->Add(factory()->NewBooleanLiteral(false, pos), zone());
Expression* call_runtime = factory()->NewCallRuntime(
Context::PROMISE_INTERNAL_REJECT_INDEX, args, pos);
return factory()->NewBinaryOperation(
Token::COMMA, call_runtime,
factory()->NewVariableProxy(PromiseVariable()), pos);
}
Variable* Parser::PromiseVariable() {
// Based on the various compilation paths, there are many different code
// paths which may be the first to access the Promise temporary. Whichever
// comes first should create it and stash it in the FunctionState.
Variable* promise = function_state_->scope()->promise_var();
if (promise == nullptr) {
promise = function_state_->scope()->DeclarePromiseVar(
ast_value_factory()->empty_string());
}
return promise;
}
Expression* Parser::BuildInitialYield(int pos, FunctionKind kind) {
Expression* yield_result = factory()->NewVariableProxy(
function_state_->scope()->generator_object_var());
// The position of the yield is important for reporting the exception
// caused by calling the .throw method on a generator suspended at the
// initial yield (i.e. right after generator instantiation).
return factory()->NewYield(yield_result, scope()->start_position(),
Suspend::kOnExceptionThrow);
}
ZoneList<Statement*>* Parser::ParseFunction(
const AstRawString* function_name, int pos, FunctionKind kind,
FunctionLiteral::FunctionType function_type,
DeclarationScope* function_scope, int* num_parameters, int* function_length,
bool* has_duplicate_parameters, int* expected_property_count, bool* ok) {
ParsingModeScope mode(this, allow_lazy_ ? PARSE_LAZILY : PARSE_EAGERLY);
FunctionState function_state(&function_state_, &scope_, function_scope);
DuplicateFinder duplicate_finder;
ExpressionClassifier formals_classifier(this, &duplicate_finder);
int expected_parameters_end_pos = parameters_end_pos_;
if (expected_parameters_end_pos != kNoSourcePosition) {
// This is the first function encountered in a CreateDynamicFunction eval.
parameters_end_pos_ = kNoSourcePosition;
// The function name should have been ignored, giving us the empty string
// here.
DCHECK_EQ(function_name, ast_value_factory()->empty_string());
}
ParserFormalParameters formals(function_scope);
ParseFormalParameterList(&formals, CHECK_OK);
if (expected_parameters_end_pos != kNoSourcePosition) {
// Check for '(' or ')' shenanigans in the parameter string for dynamic
// functions.
int position = peek_position();
if (position < expected_parameters_end_pos) {
ReportMessageAt(Scanner::Location(position, position + 1),
MessageTemplate::kArgStringTerminatesParametersEarly);
*ok = false;
return nullptr;
} else if (position > expected_parameters_end_pos) {
ReportMessageAt(Scanner::Location(expected_parameters_end_pos - 2,
expected_parameters_end_pos),
MessageTemplate::kUnexpectedEndOfArgString);
*ok = false;
return nullptr;
}
}
Expect(Token::RPAREN, CHECK_OK);
int formals_end_position = scanner()->location().end_pos;
*num_parameters = formals.num_parameters();
*function_length = formals.function_length;
CheckArityRestrictions(formals.arity, kind, formals.has_rest,
function_scope->start_position(), formals_end_position,
CHECK_OK);
Expect(Token::LBRACE, CHECK_OK);
ZoneList<Statement*>* body = new (zone()) ZoneList<Statement*>(8, zone());
ParseFunctionBody(body, function_name, pos, formals, kind, function_type, ok);
// Validate parameter names. We can do this only after parsing the function,
// since the function can declare itself strict.
const bool allow_duplicate_parameters =
is_sloppy(function_scope->language_mode()) && formals.is_simple &&
!IsConciseMethod(kind);
ValidateFormalParameters(function_scope->language_mode(),
allow_duplicate_parameters, CHECK_OK);
RewriteDestructuringAssignments();
*has_duplicate_parameters =
!classifier()->is_valid_formal_parameter_list_without_duplicates();
*expected_property_count = function_state.expected_property_count();
return body;
}
void Parser::DeclareClassVariable(const AstRawString* name,
ClassInfo* class_info, int class_token_pos,
bool* ok) {
#ifdef DEBUG
scope()->SetScopeName(name);
#endif
if (name != nullptr) {
VariableProxy* proxy = factory()->NewVariableProxy(name, NORMAL_VARIABLE);
Declaration* declaration =
factory()->NewVariableDeclaration(proxy, class_token_pos);
class_info->variable =
Declare(declaration, DeclarationDescriptor::NORMAL, CONST,
Variable::DefaultInitializationFlag(CONST), ok);
}
}
// TODO(gsathya): Ideally, this should just bypass scope analysis and
// allocate a slot directly on the context. We should just store this
// index in the AST, instead of storing the variable.
Variable* Parser::CreateSyntheticContextVariable(const AstRawString* name,
bool* ok) {
VariableProxy* proxy = factory()->NewVariableProxy(name, NORMAL_VARIABLE);
Declaration* declaration =
factory()->NewVariableDeclaration(proxy, kNoSourcePosition);
Variable* var = Declare(declaration, DeclarationDescriptor::NORMAL, CONST,
Variable::DefaultInitializationFlag(CONST), CHECK_OK);
var->ForceContextAllocation();
return var;
}
// This method declares a property of the given class. It updates the
// following fields of class_info, as appropriate:
// - constructor
// - properties
void Parser::DeclareClassProperty(const AstRawString* class_name,
ClassLiteralProperty* property,
ClassLiteralProperty::Kind kind,
bool is_static, bool is_constructor,
bool is_computed_name, ClassInfo* class_info,
bool* ok) {
if (is_constructor) {
DCHECK(!class_info->constructor);
class_info->constructor = property->value()->AsFunctionLiteral();
DCHECK_NOT_NULL(class_info->constructor);
class_info->constructor->set_raw_name(
class_name != nullptr ? ast_value_factory()->NewConsString(class_name)
: nullptr);
return;
}
if (kind != ClassLiteralProperty::FIELD) {
class_info->properties->Add(property, zone());
return;
}
DCHECK(allow_harmony_public_fields());
if (is_static) {
class_info->static_fields->Add(property, zone());
} else {
class_info->instance_fields->Add(property, zone());
}
if (is_computed_name) {
// We create a synthetic variable name here so that scope
// analysis doesn't dedupe the vars.
Variable* computed_name_var = CreateSyntheticContextVariable(
ClassFieldVariableName(ast_value_factory(),
class_info->computed_field_count),
CHECK_OK_VOID);
property->set_computed_name_var(computed_name_var);
class_info->properties->Add(property, zone());
}
}
FunctionLiteral* Parser::CreateInitializerFunction(
DeclarationScope* scope, ZoneList<ClassLiteral::Property*>* fields) {
// function() { .. class fields initializer .. }
ZoneList<Statement*>* statements = NewStatementList(1);
InitializeClassFieldsStatement* static_fields =
factory()->NewInitializeClassFieldsStatement(fields, kNoSourcePosition);
statements->Add(static_fields, zone());
return factory()->NewFunctionLiteral(
ast_value_factory()->empty_string(), scope, statements, 0, 0, 0,
FunctionLiteral::kNoDuplicateParameters,
FunctionLiteral::kAnonymousExpression,
FunctionLiteral::kShouldEagerCompile, scope->start_position(), true,
GetNextFunctionLiteralId());
}
// This method generates a ClassLiteral AST node.
// It uses the following fields of class_info:
// - constructor (if missing, it updates it with a default constructor)
// - proxy
// - extends
// - properties
// - has_name_static_property
// - has_static_computed_names
Expression* Parser::RewriteClassLiteral(Scope* block_scope,
const AstRawString* name,
ClassInfo* class_info, int pos,
int end_pos, bool* ok) {
DCHECK_NOT_NULL(block_scope);
DCHECK_EQ(block_scope->scope_type(), BLOCK_SCOPE);
DCHECK_EQ(block_scope->language_mode(), LanguageMode::kStrict);
bool has_extends = class_info->extends != nullptr;
bool has_default_constructor = class_info->constructor == nullptr;
if (has_default_constructor) {
class_info->constructor =
DefaultConstructor(name, has_extends, pos, end_pos);
}
if (name != nullptr) {
DCHECK_NOT_NULL(class_info->variable);
class_info->variable->set_initializer_position(end_pos);
}
FunctionLiteral* static_fields_initializer = nullptr;
if (class_info->has_static_class_fields) {
static_fields_initializer = CreateInitializerFunction(
class_info->static_fields_scope, class_info->static_fields);
}
FunctionLiteral* instance_fields_initializer_function = nullptr;
if (class_info->has_instance_class_fields) {
instance_fields_initializer_function = CreateInitializerFunction(
class_info->instance_fields_scope, class_info->instance_fields);
class_info->constructor->set_requires_instance_fields_initializer(true);
}
ClassLiteral* class_literal = factory()->NewClassLiteral(
block_scope, class_info->variable, class_info->extends,
class_info->constructor, class_info->properties,
static_fields_initializer, instance_fields_initializer_function, pos,
end_pos, class_info->has_name_static_property,
class_info->has_static_computed_names, class_info->is_anonymous);
AddFunctionForNameInference(class_info->constructor);
return class_literal;
}
void Parser::CheckConflictingVarDeclarations(Scope* scope, bool* ok) {
Declaration* decl = scope->CheckConflictingVarDeclarations();
if (decl != nullptr) {
// In ES6, conflicting variable bindings are early errors.
const AstRawString* name = decl->proxy()->raw_name();
int position = decl->proxy()->position();
Scanner::Location location =
position == kNoSourcePosition
? Scanner::Location::invalid()
: Scanner::Location(position, position + 1);
ReportMessageAt(location, MessageTemplate::kVarRedeclaration, name);
*ok = false;
}
}
void Parser::InsertShadowingVarBindingInitializers(Block* inner_block) {
// For each var-binding that shadows a parameter, insert an assignment
// initializing the variable with the parameter.
Scope* inner_scope = inner_block->scope();
DCHECK(inner_scope->is_declaration_scope());
Scope* function_scope = inner_scope->outer_scope();
DCHECK(function_scope->is_function_scope());
BlockState block_state(&scope_, inner_scope);
for (Declaration* decl : *inner_scope->declarations()) {
if (decl->proxy()->var()->mode() != VAR || !decl->IsVariableDeclaration()) {
continue;
}
const AstRawString* name = decl->proxy()->raw_name();
Variable* parameter = function_scope->LookupLocal(name);
if (parameter == nullptr) continue;
VariableProxy* to = NewUnresolved(name);
VariableProxy* from = factory()->NewVariableProxy(parameter);
Expression* assignment =
factory()->NewAssignment(Token::ASSIGN, to, from, kNoSourcePosition);
Statement* statement =
factory()->NewExpressionStatement(assignment, kNoSourcePosition);
inner_block->statements()->InsertAt(0, statement, zone());
}
}
void Parser::InsertSloppyBlockFunctionVarBindings(DeclarationScope* scope) {
// For the outermost eval scope, we cannot hoist during parsing: let
// declarations in the surrounding scope may prevent hoisting, but the
// information is unaccessible during parsing. In this case, we hoist later in
// DeclarationScope::Analyze.
if (scope->is_eval_scope() && scope->outer_scope() == original_scope_) {
return;
}
scope->HoistSloppyBlockFunctions(factory());
}
// ----------------------------------------------------------------------------
// Parser support
bool Parser::TargetStackContainsLabel(const AstRawString* label) {
for (ParserTarget* t = target_stack_; t != nullptr; t = t->previous()) {
if (ContainsLabel(t->statement()->labels(), label)) return true;
}
return false;
}
BreakableStatement* Parser::LookupBreakTarget(const AstRawString* label,
bool* ok) {
bool anonymous = label == nullptr;
for (ParserTarget* t = target_stack_; t != nullptr; t = t->previous()) {
BreakableStatement* stat = t->statement();
if ((anonymous && stat->is_target_for_anonymous()) ||
(!anonymous && ContainsLabel(stat->labels(), label))) {
return stat;
}
}
return nullptr;
}
IterationStatement* Parser::LookupContinueTarget(const AstRawString* label,
bool* ok) {
bool anonymous = label == nullptr;
for (ParserTarget* t = target_stack_; t != nullptr; t = t->previous()) {
IterationStatement* stat = t->statement()->AsIterationStatement();
if (stat == nullptr) continue;
DCHECK(stat->is_target_for_anonymous());
if (anonymous || ContainsLabel(stat->labels(), label)) {
return stat;
}
}
return nullptr;
}
void Parser::HandleSourceURLComments(Isolate* isolate, Handle<Script> script) {
Handle<String> source_url = scanner_.SourceUrl(isolate);
if (!source_url.is_null()) {
script->set_source_url(*source_url);
}
Handle<String> source_mapping_url = scanner_.SourceMappingUrl(isolate);
if (!source_mapping_url.is_null()) {
script->set_source_mapping_url(*source_mapping_url);
}
}
void Parser::UpdateStatistics(Isolate* isolate, Handle<Script> script) {
// Move statistics to Isolate.
for (int feature = 0; feature < v8::Isolate::kUseCounterFeatureCount;
++feature) {
if (use_counts_[feature] > 0) {
isolate->CountUsage(v8::Isolate::UseCounterFeature(feature));
}
}
if (scanner_.FoundHtmlComment()) {
isolate->CountUsage(v8::Isolate::kHtmlComment);
if (script->line_offset() == 0 && script->column_offset() == 0) {
isolate->CountUsage(v8::Isolate::kHtmlCommentInExternalScript);
}
}
isolate->counters()->total_preparse_skipped()->Increment(
total_preparse_skipped_);
}
void Parser::ParseOnBackground(ParseInfo* info) {
RuntimeCallTimerScope runtimeTimer(
runtime_call_stats_, RuntimeCallCounterId::kParseBackgroundProgram);
parsing_on_main_thread_ = false;
if (!info->script().is_null()) {
set_script_id(info->script()->id());
}
DCHECK_NULL(info->literal());
FunctionLiteral* result = nullptr;
ParserLogger logger;
if (produce_cached_parse_data()) {
if (allow_lazy_) {
log_ = &logger;
} else {
compile_options_ = ScriptCompiler::kNoCompileOptions;
}
}
scanner_.Initialize(info->character_stream(), info->is_module());
DCHECK(info->maybe_outer_scope_info().is_null());
DCHECK(original_scope_);
// When streaming, we don't know the length of the source until we have parsed
// it. The raw data can be UTF-8, so we wouldn't know the source length until
// we have decoded it anyway even if we knew the raw data length (which we
// don't). We work around this by storing all the scopes which need their end
// position set at the end of the script (the top scope and possible eval
// scopes) and set their end position after we know the script length.
if (info->is_toplevel()) {
fni_ = new (zone()) FuncNameInferrer(ast_value_factory(), zone());
result = DoParseProgram(info);
} else {
result = DoParseFunction(info, info->function_name());
}
MaybeResetCharacterStream(info, result);
info->set_literal(result);
// We cannot internalize on a background thread; a foreground task will take
// care of calling AstValueFactory::Internalize just before compilation.
if (produce_cached_parse_data()) {
if (result != nullptr) *info->cached_data() = logger.GetScriptData();
log_ = nullptr;
}
}
Parser::TemplateLiteralState Parser::OpenTemplateLiteral(int pos) {
return new (zone()) TemplateLiteral(zone(), pos);
}
void Parser::AddTemplateSpan(TemplateLiteralState* state, bool should_cook,
bool tail) {
int end = scanner()->location().end_pos - (tail ? 1 : 2);
const AstRawString* raw = scanner()->CurrentRawSymbol(ast_value_factory());
if (should_cook) {
const AstRawString* cooked = scanner()->CurrentSymbol(ast_value_factory());
(*state)->AddTemplateSpan(cooked, raw, end, zone());
} else {
(*state)->AddTemplateSpan(nullptr, raw, end, zone());
}
}
void Parser::AddTemplateExpression(TemplateLiteralState* state,
Expression* expression) {
(*state)->AddExpression(expression, zone());
}
Expression* Parser::CloseTemplateLiteral(TemplateLiteralState* state, int start,
Expression* tag) {
TemplateLiteral* lit = *state;
int pos = lit->position();
const ZoneList<const AstRawString*>* cooked_strings = lit->cooked();
const ZoneList<const AstRawString*>* raw_strings = lit->raw();
const ZoneList<Expression*>* expressions = lit->expressions();
DCHECK_EQ(cooked_strings->length(), raw_strings->length());
DCHECK_EQ(cooked_strings->length(), expressions->length() + 1);
if (!tag) {
Expression* first_string =
factory()->NewStringLiteral(cooked_strings->at(0), kNoSourcePosition);
if (expressions->length() == 0) return first_string;
// Build N-ary addition op to simplify code-generation.
// TODO(leszeks): Could we just store this expression in the
// TemplateLiteralState and build it as we go?
NaryOperation* expr = factory()->NewNaryOperation(
Token::ADD, first_string, 2 * expressions->length());
int i = 0;
while (i < expressions->length()) {
Expression* sub = expressions->at(i++);
const AstRawString* cooked_str = cooked_strings->at(i);
DCHECK_NOT_NULL(cooked_str);
// Let middle be ToString(sub).
ZoneList<Expression*>* args =
new (zone()) ZoneList<Expression*>(1, zone());
args->Add(sub, zone());
Expression* sub_to_string = factory()->NewCallRuntime(
Runtime::kInlineToString, args, sub->position());
expr->AddSubsequent(sub_to_string, sub->position());
expr->AddSubsequent(
factory()->NewStringLiteral(cooked_str, kNoSourcePosition),
sub->position());
}
return expr;
} else {
// GetTemplateObject
const int32_t hash = ComputeTemplateLiteralHash(lit);
Expression* template_object =
factory()->NewGetTemplateObject(cooked_strings, raw_strings, hash, pos);
// Call TagFn
ZoneList<Expression*>* call_args =
new (zone()) ZoneList<Expression*>(expressions->length() + 1, zone());
call_args->Add(template_object, zone());
call_args->AddAll(*expressions, zone());
return factory()->NewTaggedTemplate(tag, call_args, pos);
}
}
namespace {
// http://burtleburtle.net/bob/hash/integer.html
uint32_t HalfAvalance(uint32_t a) {
a = (a + 0x479AB41D) + (a << 8);
a = (a ^ 0xE4AA10CE) ^ (a >> 5);
a = (a + 0x9942F0A6) - (a << 14);
a = (a ^ 0x5AEDD67D) ^ (a >> 3);
a = (a + 0x17BEA992) + (a << 7);
return a;
}
} // namespace
int32_t Parser::ComputeTemplateLiteralHash(const TemplateLiteral* lit) {
const ZoneList<const AstRawString*>* raw_strings = lit->raw();
int total = raw_strings->length();
DCHECK_GT(total, 0);
uint32_t running_hash = 0;
for (int index = 0; index < total; ++index) {
if (index) {
running_hash = StringHasher::ComputeRunningHashOneByte(
running_hash, "${}", 3);
}
const AstRawString* raw_string = raw_strings->at(index);
if (raw_string->is_one_byte()) {
const char* data = reinterpret_cast<const char*>(raw_string->raw_data());
running_hash = StringHasher::ComputeRunningHashOneByte(
running_hash, data, raw_string->length());
} else {
const uc16* data = reinterpret_cast<const uc16*>(raw_string->raw_data());
running_hash = StringHasher::ComputeRunningHash(running_hash, data,
raw_string->length());
}
}
// Pass {running_hash} throught a decent 'half avalance' hash function
// and take the most significant bits (in Smi range).
return static_cast<int32_t>(HalfAvalance(running_hash)) >>
(sizeof(int32_t) * CHAR_BIT - kSmiValueSize);
}
namespace {
bool OnlyLastArgIsSpread(ZoneList<Expression*>* args) {
for (int i = 0; i < args->length() - 1; i++) {
if (args->at(i)->IsSpread()) {
return false;
}
}
return args->at(args->length() - 1)->IsSpread();
}
} // namespace
ZoneList<Expression*>* Parser::PrepareSpreadArguments(
ZoneList<Expression*>* list) {
ZoneList<Expression*>* args = new (zone()) ZoneList<Expression*>(1, zone());
if (list->length() == 1) {
// Spread-call with single spread argument produces an InternalArray
// containing the values from the array.
//
// Function is called or constructed with the produced array of arguments
//
// EG: Apply(Func, Spread(spread0))
ZoneList<Expression*>* spread_list =
new (zone()) ZoneList<Expression*>(0, zone());
spread_list->Add(list->at(0)->AsSpread()->expression(), zone());
args->Add(factory()->NewCallRuntime(Runtime::kSpreadIterablePrepare,
spread_list, kNoSourcePosition),
zone());
return args;
} else {
// Spread-call with multiple arguments produces array literals for each
// sequences of unspread arguments, and converts each spread iterable to
// an Internal array. Finally, all of these produced arrays are flattened
// into a single InternalArray, containing the arguments for the call.
//
// EG: Apply(Func, Flatten([unspread0, unspread1], Spread(spread0),
// Spread(spread1), [unspread2, unspread3]))
int i = 0;
int n = list->length();
while (i < n) {
if (!list->at(i)->IsSpread()) {
ZoneList<Expression*>* unspread =
new (zone()) ZoneList<Expression*>(1, zone());
// Push array of unspread parameters
while (i < n && !list->at(i)->IsSpread()) {
unspread->Add(list->at(i++), zone());
}
args->Add(factory()->NewArrayLiteral(unspread, kNoSourcePosition),
zone());
if (i == n) break;
}
// Push eagerly spread argument
ZoneList<Expression*>* spread_list =
new (zone()) ZoneList<Expression*>(1, zone());
spread_list->Add(list->at(i++)->AsSpread()->expression(), zone());
args->Add(factory()->NewCallRuntime(Context::SPREAD_ITERABLE_INDEX,
spread_list, kNoSourcePosition),
zone());
}
list = new (zone()) ZoneList<Expression*>(1, zone());
list->Add(factory()->NewCallRuntime(Context::SPREAD_ARGUMENTS_INDEX, args,
kNoSourcePosition),
zone());
return list;
}
UNREACHABLE();
}
Expression* Parser::SpreadCall(Expression* function,
ZoneList<Expression*>* args, int pos,
Call::PossiblyEval is_possibly_eval) {
// Handle this case in BytecodeGenerator.
if (OnlyLastArgIsSpread(args)) {
return factory()->NewCall(function, args, pos);
}
if (function->IsSuperCallReference()) {
// Super calls
// $super_constructor = %_GetSuperConstructor(<this-function>)
// %reflect_construct($super_constructor, args, new.target)
args = PrepareSpreadArguments(args);
ZoneList<Expression*>* tmp = new (zone()) ZoneList<Expression*>(1, zone());
tmp->Add(function->AsSuperCallReference()->this_function_var(), zone());
Expression* super_constructor = factory()->NewCallRuntime(
Runtime::kInlineGetSuperConstructor, tmp, pos);
args->InsertAt(0, super_constructor, zone());
args->Add(function->AsSuperCallReference()->new_target_var(), zone());
return factory()->NewCallRuntime(Context::REFLECT_CONSTRUCT_INDEX, args,
pos);
} else {
args = PrepareSpreadArguments(args);
if (function->IsProperty()) {
// Method calls
if (function->AsProperty()->IsSuperAccess()) {
Expression* home = ThisExpression(kNoSourcePosition);
args->InsertAt(0, function, zone());
args->InsertAt(1, home, zone());
} else {
Variable* temp = NewTemporary(ast_value_factory()->empty_string());
VariableProxy* obj = factory()->NewVariableProxy(temp);
Assignment* assign_obj = factory()->NewAssignment(
Token::ASSIGN, obj, function->AsProperty()->obj(),
kNoSourcePosition);
function = factory()->NewProperty(
assign_obj, function->AsProperty()->key(), kNoSourcePosition);
args->InsertAt(0, function, zone());
obj = factory()->NewVariableProxy(temp);
args->InsertAt(1, obj, zone());
}
} else {
// Non-method calls
args->InsertAt(0, function, zone());
args->InsertAt(1, factory()->NewUndefinedLiteral(kNoSourcePosition),
zone());
}
return factory()->NewCallRuntime(Context::REFLECT_APPLY_INDEX, args, pos);
}
}
Expression* Parser::SpreadCallNew(Expression* function,
ZoneList<Expression*>* args, int pos) {
if (OnlyLastArgIsSpread(args)) {
// Handle in BytecodeGenerator.
return factory()->NewCallNew(function, args, pos);
}
args = PrepareSpreadArguments(args);
args->InsertAt(0, function, zone());
return factory()->NewCallRuntime(Context::REFLECT_CONSTRUCT_INDEX, args, pos);
}
void Parser::SetLanguageMode(Scope* scope, LanguageMode mode) {
v8::Isolate::UseCounterFeature feature;
if (is_sloppy(mode))
feature = v8::Isolate::kSloppyMode;
else if (is_strict(mode))
feature = v8::Isolate::kStrictMode;
else
UNREACHABLE();
++use_counts_[feature];
scope->SetLanguageMode(mode);
}
void Parser::SetAsmModule() {
// Store the usage count; The actual use counter on the isolate is
// incremented after parsing is done.
++use_counts_[v8::Isolate::kUseAsm];
DCHECK(scope()->is_declaration_scope());
scope()->AsDeclarationScope()->set_asm_module();
}
Expression* Parser::ExpressionListToExpression(ZoneList<Expression*>* args) {
Expression* expr = args->at(0);
for (int i = 1; i < args->length(); ++i) {
expr = factory()->NewBinaryOperation(Token::COMMA, expr, args->at(i),
expr->position());
}
return expr;
}
// This method completes the desugaring of the body of async_function.
void Parser::RewriteAsyncFunctionBody(ZoneList<Statement*>* body, Block* block,
Expression* return_value, bool* ok) {
// function async_function() {
// .generator_object = %CreateJSGeneratorObject();
// BuildRejectPromiseOnException({
// ... block ...
// return %ResolvePromise(.promise, expr), .promise;
// })
// }
return_value = BuildResolvePromise(return_value, return_value->position());
block->statements()->Add(
factory()->NewReturnStatement(return_value, return_value->position()),
zone());
block = BuildRejectPromiseOnException(block);
body->Add(block, zone());
}
void Parser::RewriteNonPattern(bool* ok) {
ValidateExpression(CHECK_OK_VOID);
auto non_patterns_to_rewrite = function_state_->non_patterns_to_rewrite();
int begin = classifier()->GetNonPatternBegin();
int end = non_patterns_to_rewrite->length();
if (begin < end) {
for (int i = begin; i < end; i++) {
RewritableExpression* expr = non_patterns_to_rewrite->at(i);
// TODO(adamk): Make this more typesafe.
DCHECK(expr->expression()->IsArrayLiteral());
ArrayLiteral* lit = expr->expression()->AsArrayLiteral();
expr->Rewrite(RewriteSpreads(lit));
}
non_patterns_to_rewrite->Rewind(begin);
}
}
void Parser::RewriteDestructuringAssignments() {
const auto& assignments =
function_state_->destructuring_assignments_to_rewrite();
for (int i = assignments.length() - 1; i >= 0; --i) {
// Rewrite list in reverse, so that nested assignment patterns are rewritten
// correctly.
RewritableExpression* to_rewrite = assignments[i];
DCHECK_NOT_NULL(to_rewrite);
if (!to_rewrite->is_rewritten()) {
// Since this function is called at the end of parsing the program,
// pair.scope may already have been removed by FinalizeBlockScope in the
// meantime.
Scope* scope = to_rewrite->scope()->GetUnremovedScope();
BlockState block_state(&scope_, scope);
RewriteDestructuringAssignment(to_rewrite);
}
}
}
Expression* Parser::RewriteSpreads(ArrayLiteral* lit) {
// Array literals containing spreads are rewritten using do expressions, e.g.
// [1, 2, 3, ...x, 4, ...y, 5]
// is roughly rewritten as:
// do {
// $R = [1, 2, 3];
// for ($i of x) %AppendElement($R, $i);
// %AppendElement($R, 4);
// for ($j of y) %AppendElement($R, $j);
// %AppendElement($R, 5);
// $R
// }
// where $R, $i and $j are fresh temporary variables.
ZoneList<Expression*>::iterator s = lit->FirstSpread();
if (s == lit->EndValue()) return nullptr; // no spread, no rewriting...
Variable* result = NewTemporary(ast_value_factory()->dot_result_string());
// NOTE: The value assigned to R is the whole original array literal,
// spreads included. This will be fixed before the rewritten AST is returned.
// $R = lit
Expression* init_result = factory()->NewAssignment(
Token::INIT, factory()->NewVariableProxy(result), lit, kNoSourcePosition);
Block* do_block = factory()->NewBlock(16, false);
do_block->statements()->Add(
factory()->NewExpressionStatement(init_result, kNoSourcePosition),
zone());
// Traverse the array literal starting from the first spread.
while (s != lit->EndValue()) {
Expression* value = *s++;
Spread* spread = value->AsSpread();
if (spread == nullptr) {
// If the element is not a spread, we're adding a single:
// %AppendElement($R, value)
// or, in case of a hole,
// ++($R.length)
if (!value->IsTheHoleLiteral()) {
ZoneList<Expression*>* append_element_args = NewExpressionList(2);
append_element_args->Add(factory()->NewVariableProxy(result), zone());
append_element_args->Add(value, zone());
do_block->statements()->Add(
factory()->NewExpressionStatement(
factory()->NewCallRuntime(Runtime::kAppendElement,
append_element_args,
kNoSourcePosition),
kNoSourcePosition),
zone());
} else {
Property* length_property = factory()->NewProperty(
factory()->NewVariableProxy(result),
factory()->NewStringLiteral(ast_value_factory()->length_string(),
kNoSourcePosition),
kNoSourcePosition);
CountOperation* count_op = factory()->NewCountOperation(
Token::INC, true /* prefix */, length_property, kNoSourcePosition);
do_block->statements()->Add(
factory()->NewExpressionStatement(count_op, kNoSourcePosition),
zone());
}
} else {
// If it's a spread, we're adding a for/of loop iterating through it.
Variable* each = NewTemporary(ast_value_factory()->dot_for_string());
Expression* subject = spread->expression();
// %AppendElement($R, each)
Statement* append_body;
{
ZoneList<Expression*>* append_element_args = NewExpressionList(2);
append_element_args->Add(factory()->NewVariableProxy(result), zone());
append_element_args->Add(factory()->NewVariableProxy(each), zone());
append_body = factory()->NewExpressionStatement(
factory()->NewCallRuntime(Runtime::kAppendElement,
append_element_args, kNoSourcePosition),
kNoSourcePosition);
}
// for (each of spread) %AppendElement($R, each)
ForOfStatement* loop =
factory()->NewForOfStatement(nullptr, kNoSourcePosition);
const bool finalize = false;
InitializeForOfStatement(loop, factory()->NewVariableProxy(each), subject,
append_body, finalize, IteratorType::kNormal);
do_block->statements()->Add(loop, zone());
}
}
// Now, rewind the original array literal to truncate everything from the
// first spread (included) until the end. This fixes $R's initialization.
lit->RewindSpreads();
return factory()->NewDoExpression(do_block, result, lit->position());
}
void Parser::QueueDestructuringAssignmentForRewriting(
RewritableExpression* expr) {
function_state_->AddDestructuringAssignment(expr);
}
void Parser::QueueNonPatternForRewriting(RewritableExpression* expr, bool* ok) {
function_state_->AddNonPatternForRewriting(expr, ok);
}
void Parser::SetFunctionNameFromPropertyName(LiteralProperty* property,
const AstRawString* name,
const AstRawString* prefix) {
// Ensure that the function we are going to create has shared name iff
// we are not going to set it later.
if (property->NeedsSetFunctionName()) {
name = nullptr;
prefix = nullptr;
} else {
// If the property value is an anonymous function or an anonymous class or
// a concise method or an accessor function which doesn't require the name
// to be set then the shared name must be provided.
DCHECK_IMPLIES(property->value()->IsAnonymousFunctionDefinition() ||
property->value()->IsConciseMethodDefinition() ||
property->value()->IsAccessorFunctionDefinition(),
name != nullptr);
}
Expression* value = property->value();
SetFunctionName(value, name, prefix);
}
void Parser::SetFunctionNameFromPropertyName(ObjectLiteralProperty* property,
const AstRawString* name,
const AstRawString* prefix) {
// Ignore "__proto__" as a name when it's being used to set the [[Prototype]]
// of an object literal.
// See ES #sec-__proto__-property-names-in-object-initializers.
if (property->IsPrototype()) return;
DCHECK(!property->value()->IsAnonymousFunctionDefinition() ||
property->kind() == ObjectLiteralProperty::COMPUTED);
SetFunctionNameFromPropertyName(static_cast<LiteralProperty*>(property), name,
prefix);
}
void Parser::SetFunctionNameFromIdentifierRef(Expression* value,
Expression* identifier) {
if (!identifier->IsVariableProxy()) return;
SetFunctionName(value, identifier->AsVariableProxy()->raw_name());
}
void Parser::SetFunctionName(Expression* value, const AstRawString* name,
const AstRawString* prefix) {
if (!value->IsAnonymousFunctionDefinition() &&
!value->IsConciseMethodDefinition() &&
!value->IsAccessorFunctionDefinition()) {
return;
}
auto function = value->AsFunctionLiteral();
if (value->IsClassLiteral()) {
function = value->AsClassLiteral()->constructor();
}
if (function != nullptr) {
AstConsString* cons_name = nullptr;
if (name != nullptr) {
if (prefix != nullptr) {
cons_name = ast_value_factory()->NewConsString(prefix, name);
} else {
cons_name = ast_value_factory()->NewConsString(name);
}
} else {
DCHECK_NULL(prefix);
}
function->set_raw_name(cons_name);
}
}
Statement* Parser::CheckCallable(Variable* var, Expression* error, int pos) {
const int nopos = kNoSourcePosition;
Statement* validate_var;
{
Expression* type_of = factory()->NewUnaryOperation(
Token::TYPEOF, factory()->NewVariableProxy(var), nopos);
Expression* function_literal = factory()->NewStringLiteral(
ast_value_factory()->function_string(), nopos);
Expression* condition = factory()->NewCompareOperation(
Token::EQ_STRICT, type_of, function_literal, nopos);
Statement* throw_call = factory()->NewExpressionStatement(error, pos);
validate_var = factory()->NewIfStatement(
condition, factory()->NewEmptyStatement(nopos), throw_call, nopos);
}
return validate_var;
}
void Parser::BuildIteratorClose(ZoneList<Statement*>* statements,
Variable* iterator, Variable* input,
Variable* var_output, IteratorType type) {
//
// This function adds four statements to [statements], corresponding to the
// following code:
//
// let iteratorReturn = iterator.return;
// if (IS_NULL_OR_UNDEFINED(iteratorReturn) {
// return {value: input, done: true};
// }
// output = %_Call(iteratorReturn, iterator, input);
// if (!IS_RECEIVER(output)) %ThrowIterResultNotAnObject(output);
//
const int nopos = kNoSourcePosition;
// let iteratorReturn = iterator.return;
Variable* var_return = var_output; // Reusing the output variable.
Statement* get_return;
{
Expression* iterator_proxy = factory()->NewVariableProxy(iterator);
Expression* literal = factory()->NewStringLiteral(
ast_value_factory()->return_string(), nopos);
Expression* property =
factory()->NewProperty(iterator_proxy, literal, nopos);
Expression* return_proxy = factory()->NewVariableProxy(var_return);
Expression* assignment =
factory()->NewAssignment(Token::ASSIGN, return_proxy, property, nopos);
get_return = factory()->NewExpressionStatement(assignment, nopos);
}
// if (IS_NULL_OR_UNDEFINED(iteratorReturn) {
// return {value: input, done: true};
// }
Statement* check_return;
{
Expression* condition = factory()->NewCompareOperation(
Token::EQ, factory()->NewVariableProxy(var_return),
factory()->NewNullLiteral(nopos), nopos);
Expression* value = factory()->NewVariableProxy(input);
Statement* return_input = BuildReturnStatement(value, nopos);
check_return = factory()->NewIfStatement(
condition, return_input, factory()->NewEmptyStatement(nopos), nopos);
}
// output = %_Call(iteratorReturn, iterator, input);
Statement* call_return;
{
auto args = new (zone()) ZoneList<Expression*>(3, zone());
args->Add(factory()->NewVariableProxy(var_return), zone());
args->Add(factory()->NewVariableProxy(iterator), zone());
args->Add(factory()->NewVariableProxy(input), zone());
Expression* call =
factory()->NewCallRuntime(Runtime::kInlineCall, args, nopos);
if (type == IteratorType::kAsync) {
call = factory()->NewAwait(call, nopos);
}
Expression* output_proxy = factory()->NewVariableProxy(var_output);
Expression* assignment =
factory()->NewAssignment(Token::ASSIGN, output_proxy, call, nopos);
call_return = factory()->NewExpressionStatement(assignment, nopos);
}
// if (!IS_RECEIVER(output)) %ThrowIteratorResultNotAnObject(output);
Statement* validate_output;
{
Expression* is_receiver_call;
{
auto args = new (zone()) ZoneList<Expression*>(1, zone());
args->Add(factory()->NewVariableProxy(var_output), zone());
is_receiver_call =
factory()->NewCallRuntime(Runtime::kInlineIsJSReceiver, args, nopos);
}
Statement* throw_call;
{
auto args = new (zone()) ZoneList<Expression*>(1, zone());
args->Add(factory()->NewVariableProxy(var_output), zone());
Expression* call = factory()->NewCallRuntime(
Runtime::kThrowIteratorResultNotAnObject, args, nopos);
throw_call = factory()->NewExpressionStatement(call, nopos);
}
validate_output = factory()->NewIfStatement(
is_receiver_call, factory()->NewEmptyStatement(nopos), throw_call,
nopos);
}
statements->Add(get_return, zone());
statements->Add(check_return, zone());
statements->Add(call_return, zone());
statements->Add(validate_output, zone());
}
void Parser::FinalizeIteratorUse(Variable* completion, Expression* condition,
Variable* iter, Block* iterator_use,
Block* target, IteratorType type) {
//
// This function adds two statements to [target], corresponding to the
// following code:
//
// completion = kNormalCompletion;
// try {
// try {
// iterator_use
// } catch(e) {
// if (completion === kAbruptCompletion) completion = kThrowCompletion;
// %ReThrow(e);
// }
// } finally {
// if (condition) {
// #BuildIteratorCloseForCompletion(iter, completion)
// }
// }
//
const int nopos = kNoSourcePosition;
// completion = kNormalCompletion;
Statement* initialize_completion;
{
Expression* proxy = factory()->NewVariableProxy(completion);
Expression* assignment = factory()->NewAssignment(
Token::ASSIGN, proxy,
factory()->NewSmiLiteral(Parser::kNormalCompletion, nopos), nopos);
initialize_completion =
factory()->NewExpressionStatement(assignment, nopos);
}
// if (completion === kAbruptCompletion) completion = kThrowCompletion;
Statement* set_completion_throw;
{
Expression* condition = factory()->NewCompareOperation(
Token::EQ_STRICT, factory()->NewVariableProxy(completion),
factory()->NewSmiLiteral(Parser::kAbruptCompletion, nopos), nopos);
Expression* proxy = factory()->NewVariableProxy(completion);
Expression* assignment = factory()->NewAssignment(
Token::ASSIGN, proxy,
factory()->NewSmiLiteral(Parser::kThrowCompletion, nopos), nopos);
Statement* statement = factory()->NewExpressionStatement(assignment, nopos);
set_completion_throw = factory()->NewIfStatement(
condition, statement, factory()->NewEmptyStatement(nopos), nopos);
}
// if (condition) {
// #BuildIteratorCloseForCompletion(iter, completion)
// }
Block* maybe_close;
{
Block* block = factory()->NewBlock(2, true);
Expression* proxy = factory()->NewVariableProxy(completion);
BuildIteratorCloseForCompletion(block->statements(), iter, proxy, type);
DCHECK_EQ(block->statements()->length(), 2);
maybe_close = IgnoreCompletion(factory()->NewIfStatement(
condition, block, factory()->NewEmptyStatement(nopos), nopos));
}
// try { #try_block }
// catch(e) {
// #set_completion_throw;
// %ReThrow(e);
// }
Statement* try_catch;
{
Scope* catch_scope = NewHiddenCatchScope();
Statement* rethrow;
// We use %ReThrow rather than the ordinary throw because we want to
// preserve the original exception message. This is also why we create a
// TryCatchStatementForReThrow below (which does not clear the pending
// message), rather than a TryCatchStatement.
{
auto args = new (zone()) ZoneList<Expression*>(1, zone());
args->Add(factory()->NewVariableProxy(catch_scope->catch_variable()),
zone());
rethrow = factory()->NewExpressionStatement(
factory()->NewCallRuntime(Runtime::kReThrow, args, nopos), nopos);
}
Block* catch_block = factory()->NewBlock(2, false);
catch_block->statements()->Add(set_completion_throw, zone());
catch_block->statements()->Add(rethrow, zone());
try_catch = factory()->NewTryCatchStatementForReThrow(
iterator_use, catch_scope, catch_block, nopos);
}
// try { #try_catch } finally { #maybe_close }
Statement* try_finally;
{
Block* try_block = factory()->NewBlock(1, false);
try_block->statements()->Add(try_catch, zone());
try_finally =
factory()->NewTryFinallyStatement(try_block, maybe_close, nopos);
}
target->statements()->Add(initialize_completion, zone());
target->statements()->Add(try_finally, zone());
}
void Parser::BuildIteratorCloseForCompletion(ZoneList<Statement*>* statements,
Variable* iterator,
Expression* completion,
IteratorType type) {
//
// This function adds two statements to [statements], corresponding to the
// following code:
//
// let iteratorReturn = iterator.return;
// if (!IS_NULL_OR_UNDEFINED(iteratorReturn)) {
// if (completion === kThrowCompletion) {
// if (!IS_CALLABLE(iteratorReturn)) {
// throw MakeTypeError(kReturnMethodNotCallable);
// }
// [if (IteratorType == kAsync)]
// try { Await(%_Call(iteratorReturn, iterator) } catch (_) { }
// [else]
// try { %_Call(iteratorReturn, iterator) } catch (_) { }
// [endif]
// } else {
// [if (IteratorType == kAsync)]
// let output = Await(%_Call(iteratorReturn, iterator));
// [else]
// let output = %_Call(iteratorReturn, iterator);
// [endif]
// if (!IS_RECEIVER(output)) {
// %ThrowIterResultNotAnObject(output);
// }
// }
// }
//
const int nopos = kNoSourcePosition;
// let iteratorReturn = iterator.return;
Variable* var_return = NewTemporary(ast_value_factory()->empty_string());
Statement* get_return;
{
Expression* iterator_proxy = factory()->NewVariableProxy(iterator);
Expression* literal = factory()->NewStringLiteral(
ast_value_factory()->return_string(), nopos);
Expression* property =
factory()->NewProperty(iterator_proxy, literal, nopos);
Expression* return_proxy = factory()->NewVariableProxy(var_return);
Expression* assignment =
factory()->NewAssignment(Token::ASSIGN, return_proxy, property, nopos);
get_return = factory()->NewExpressionStatement(assignment, nopos);
}
// if (!IS_CALLABLE(iteratorReturn)) {
// throw MakeTypeError(kReturnMethodNotCallable);
// }
Statement* check_return_callable;
{
Expression* throw_expr =
NewThrowTypeError(MessageTemplate::kReturnMethodNotCallable,
ast_value_factory()->empty_string(), nopos);
check_return_callable = CheckCallable(var_return, throw_expr, nopos);
}
// try { %_Call(iteratorReturn, iterator) } catch (_) { }
Statement* try_call_return;
{
auto args = new (zone()) ZoneList<Expression*>(2, zone());
args->Add(factory()->NewVariableProxy(var_return), zone());
args->Add(factory()->NewVariableProxy(iterator), zone());
Expression* call =
factory()->NewCallRuntime(Runtime::kInlineCall, args, nopos);
if (type == IteratorType::kAsync) {
call = factory()->NewAwait(call, nopos);
}
Block* try_block = factory()->NewBlock(1, false);
try_block->statements()->Add(factory()->NewExpressionStatement(call, nopos),
zone());
Block* catch_block = factory()->NewBlock(0, false);
Scope* catch_scope = NewHiddenCatchScope();
try_call_return = factory()->NewTryCatchStatement(try_block, catch_scope,
catch_block, nopos);
}
// let output = %_Call(iteratorReturn, iterator);
// if (!IS_RECEIVER(output)) {
// %ThrowIteratorResultNotAnObject(output);
// }
Block* validate_return;
{
Variable* var_output = NewTemporary(ast_value_factory()->empty_string());
Statement* call_return;
{
auto args = new (zone()) ZoneList<Expression*>(2, zone());
args->Add(factory()->NewVariableProxy(var_return), zone());
args->Add(factory()->NewVariableProxy(iterator), zone());
Expression* call =
factory()->NewCallRuntime(Runtime::kInlineCall, args, nopos);
if (type == IteratorType::kAsync) {
call = factory()->NewAwait(call, nopos);
}
Expression* output_proxy = factory()->NewVariableProxy(var_output);
Expression* assignment =
factory()->NewAssignment(Token::ASSIGN, output_proxy, call, nopos);
call_return = factory()->NewExpressionStatement(assignment, nopos);
}
Expression* is_receiver_call;
{
auto args = new (zone()) ZoneList<Expression*>(1, zone());
args->Add(factory()->NewVariableProxy(var_output), zone());
is_receiver_call =
factory()->NewCallRuntime(Runtime::kInlineIsJSReceiver, args, nopos);
}
Statement* throw_call;
{
auto args = new (zone()) ZoneList<Expression*>(1, zone());
args->Add(factory()->NewVariableProxy(var_output), zone());
Expression* call = factory()->NewCallRuntime(
Runtime::kThrowIteratorResultNotAnObject, args, nopos);
throw_call = factory()->NewExpressionStatement(call, nopos);
}
Statement* check_return = factory()->NewIfStatement(
is_receiver_call, factory()->NewEmptyStatement(nopos), throw_call,
nopos);
validate_return = factory()->NewBlock(2, false);
validate_return->statements()->Add(call_return, zone());
validate_return->statements()->Add(check_return, zone());
}
// if (completion === kThrowCompletion) {
// #check_return_callable;
// #try_call_return;
// } else {
// #validate_return;
// }
Statement* call_return_carefully;
{
Expression* condition = factory()->NewCompareOperation(
Token::EQ_STRICT, completion,
factory()->NewSmiLiteral(Parser::kThrowCompletion, nopos), nopos);
Block* then_block = factory()->NewBlock(2, false);
then_block->statements()->Add(check_return_callable, zone());
then_block->statements()->Add(try_call_return, zone());
call_return_carefully = factory()->NewIfStatement(condition, then_block,
validate_return, nopos);
}
// if (!IS_NULL_OR_UNDEFINED(iteratorReturn)) { ... }
Statement* maybe_call_return;
{
Expression* condition = factory()->NewCompareOperation(
Token::EQ, factory()->NewVariableProxy(var_return),
factory()->NewNullLiteral(nopos), nopos);
maybe_call_return = factory()->NewIfStatement(
condition, factory()->NewEmptyStatement(nopos), call_return_carefully,
nopos);
}
statements->Add(get_return, zone());
statements->Add(maybe_call_return, zone());
}
Statement* Parser::FinalizeForOfStatement(ForOfStatement* loop,
Variable* var_completion,
IteratorType type, int pos) {
//
// This function replaces the loop with the following wrapping:
//
// completion = kNormalCompletion;
// try {
// try {
// #loop;
// } catch(e) {
// if (completion === kAbruptCompletion) completion = kThrowCompletion;
// %ReThrow(e);
// }
// } finally {
// if (!(completion === kNormalCompletion)) {
// #BuildIteratorCloseForCompletion(#iterator, completion)
// }
// }
//
// Note that the loop's body and its assign_each already contain appropriate
// assignments to completion (see InitializeForOfStatement).
//
const int nopos = kNoSourcePosition;
// !(completion === kNormalCompletion)
Expression* closing_condition;
{
Expression* cmp = factory()->NewCompareOperation(
Token::EQ_STRICT, factory()->NewVariableProxy(var_completion),
factory()->NewSmiLiteral(Parser::kNormalCompletion, nopos), nopos);
closing_condition = factory()->NewUnaryOperation(Token::NOT, cmp, nopos);
}
Block* final_loop = factory()->NewBlock(2, false);
{
Block* try_block = factory()->NewBlock(1, false);
try_block->statements()->Add(loop, zone());
FinalizeIteratorUse(var_completion, closing_condition, loop->iterator(),
try_block, final_loop, type);
}
return final_loop;
}
#undef CHECK_OK
#undef CHECK_OK_VOID
#undef CHECK_FAILED
} // namespace internal
} // namespace v8