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parser.cc
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parser.cc
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// Copyright 2011 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "v8.h"
#include "api.h"
#include "ast-inl.h"
#include "bootstrapper.h"
#include "codegen.h"
#include "compiler.h"
#include "func-name-inferrer.h"
#include "messages.h"
#include "parser.h"
#include "platform.h"
#include "preparser.h"
#include "runtime.h"
#include "scopeinfo.h"
#include "string-stream.h"
namespace v8 {
namespace internal {
// PositionStack is used for on-stack allocation of token positions for
// new expressions. Please look at ParseNewExpression.
class PositionStack {
public:
explicit PositionStack(bool* ok) : top_(NULL), ok_(ok) {}
~PositionStack() { ASSERT(!*ok_ || is_empty()); }
class Element {
public:
Element(PositionStack* stack, int value) {
previous_ = stack->top();
value_ = value;
stack->set_top(this);
}
private:
Element* previous() { return previous_; }
int value() { return value_; }
friend class PositionStack;
Element* previous_;
int value_;
};
bool is_empty() { return top_ == NULL; }
int pop() {
ASSERT(!is_empty());
int result = top_->value();
top_ = top_->previous();
return result;
}
private:
Element* top() { return top_; }
void set_top(Element* value) { top_ = value; }
Element* top_;
bool* ok_;
};
RegExpBuilder::RegExpBuilder()
: zone_(Isolate::Current()->zone()),
pending_empty_(false),
characters_(NULL),
terms_(),
alternatives_()
#ifdef DEBUG
, last_added_(ADD_NONE)
#endif
{}
void RegExpBuilder::FlushCharacters() {
pending_empty_ = false;
if (characters_ != NULL) {
RegExpTree* atom = new(zone()) RegExpAtom(characters_->ToConstVector());
characters_ = NULL;
text_.Add(atom);
LAST(ADD_ATOM);
}
}
void RegExpBuilder::FlushText() {
FlushCharacters();
int num_text = text_.length();
if (num_text == 0) {
return;
} else if (num_text == 1) {
terms_.Add(text_.last());
} else {
RegExpText* text = new(zone()) RegExpText();
for (int i = 0; i < num_text; i++)
text_.Get(i)->AppendToText(text);
terms_.Add(text);
}
text_.Clear();
}
void RegExpBuilder::AddCharacter(uc16 c) {
pending_empty_ = false;
if (characters_ == NULL) {
characters_ = new(zone()) ZoneList<uc16>(4);
}
characters_->Add(c);
LAST(ADD_CHAR);
}
void RegExpBuilder::AddEmpty() {
pending_empty_ = true;
}
void RegExpBuilder::AddAtom(RegExpTree* term) {
if (term->IsEmpty()) {
AddEmpty();
return;
}
if (term->IsTextElement()) {
FlushCharacters();
text_.Add(term);
} else {
FlushText();
terms_.Add(term);
}
LAST(ADD_ATOM);
}
void RegExpBuilder::AddAssertion(RegExpTree* assert) {
FlushText();
terms_.Add(assert);
LAST(ADD_ASSERT);
}
void RegExpBuilder::NewAlternative() {
FlushTerms();
}
void RegExpBuilder::FlushTerms() {
FlushText();
int num_terms = terms_.length();
RegExpTree* alternative;
if (num_terms == 0) {
alternative = RegExpEmpty::GetInstance();
} else if (num_terms == 1) {
alternative = terms_.last();
} else {
alternative = new(zone()) RegExpAlternative(terms_.GetList());
}
alternatives_.Add(alternative);
terms_.Clear();
LAST(ADD_NONE);
}
RegExpTree* RegExpBuilder::ToRegExp() {
FlushTerms();
int num_alternatives = alternatives_.length();
if (num_alternatives == 0) {
return RegExpEmpty::GetInstance();
}
if (num_alternatives == 1) {
return alternatives_.last();
}
return new(zone()) RegExpDisjunction(alternatives_.GetList());
}
void RegExpBuilder::AddQuantifierToAtom(int min,
int max,
RegExpQuantifier::Type type) {
if (pending_empty_) {
pending_empty_ = false;
return;
}
RegExpTree* atom;
if (characters_ != NULL) {
ASSERT(last_added_ == ADD_CHAR);
// Last atom was character.
Vector<const uc16> char_vector = characters_->ToConstVector();
int num_chars = char_vector.length();
if (num_chars > 1) {
Vector<const uc16> prefix = char_vector.SubVector(0, num_chars - 1);
text_.Add(new(zone()) RegExpAtom(prefix));
char_vector = char_vector.SubVector(num_chars - 1, num_chars);
}
characters_ = NULL;
atom = new(zone()) RegExpAtom(char_vector);
FlushText();
} else if (text_.length() > 0) {
ASSERT(last_added_ == ADD_ATOM);
atom = text_.RemoveLast();
FlushText();
} else if (terms_.length() > 0) {
ASSERT(last_added_ == ADD_ATOM);
atom = terms_.RemoveLast();
if (atom->max_match() == 0) {
// Guaranteed to only match an empty string.
LAST(ADD_TERM);
if (min == 0) {
return;
}
terms_.Add(atom);
return;
}
} else {
// Only call immediately after adding an atom or character!
UNREACHABLE();
return;
}
terms_.Add(new(zone()) RegExpQuantifier(min, max, type, atom));
LAST(ADD_TERM);
}
Handle<String> Parser::LookupSymbol(int symbol_id) {
// Length of symbol cache is the number of identified symbols.
// If we are larger than that, or negative, it's not a cached symbol.
// This might also happen if there is no preparser symbol data, even
// if there is some preparser data.
if (static_cast<unsigned>(symbol_id)
>= static_cast<unsigned>(symbol_cache_.length())) {
if (scanner().is_literal_ascii()) {
return isolate()->factory()->LookupAsciiSymbol(
scanner().literal_ascii_string());
} else {
return isolate()->factory()->LookupTwoByteSymbol(
scanner().literal_uc16_string());
}
}
return LookupCachedSymbol(symbol_id);
}
Handle<String> Parser::LookupCachedSymbol(int symbol_id) {
// Make sure the cache is large enough to hold the symbol identifier.
if (symbol_cache_.length() <= symbol_id) {
// Increase length to index + 1.
symbol_cache_.AddBlock(Handle<String>::null(),
symbol_id + 1 - symbol_cache_.length());
}
Handle<String> result = symbol_cache_.at(symbol_id);
if (result.is_null()) {
if (scanner().is_literal_ascii()) {
result = isolate()->factory()->LookupAsciiSymbol(
scanner().literal_ascii_string());
} else {
result = isolate()->factory()->LookupTwoByteSymbol(
scanner().literal_uc16_string());
}
symbol_cache_.at(symbol_id) = result;
return result;
}
isolate()->counters()->total_preparse_symbols_skipped()->Increment();
return result;
}
FunctionEntry ScriptDataImpl::GetFunctionEntry(int start) {
// The current pre-data entry must be a FunctionEntry with the given
// start position.
if ((function_index_ + FunctionEntry::kSize <= store_.length())
&& (static_cast<int>(store_[function_index_]) == start)) {
int index = function_index_;
function_index_ += FunctionEntry::kSize;
return FunctionEntry(store_.SubVector(index,
index + FunctionEntry::kSize));
}
return FunctionEntry();
}
int ScriptDataImpl::GetSymbolIdentifier() {
return ReadNumber(&symbol_data_);
}
bool ScriptDataImpl::SanityCheck() {
// Check that the header data is valid and doesn't specify
// point to positions outside the store.
if (store_.length() < PreparseDataConstants::kHeaderSize) return false;
if (magic() != PreparseDataConstants::kMagicNumber) return false;
if (version() != PreparseDataConstants::kCurrentVersion) return false;
if (has_error()) {
// Extra sane sanity check for error message encoding.
if (store_.length() <= PreparseDataConstants::kHeaderSize
+ PreparseDataConstants::kMessageTextPos) {
return false;
}
if (Read(PreparseDataConstants::kMessageStartPos) >
Read(PreparseDataConstants::kMessageEndPos)) {
return false;
}
unsigned arg_count = Read(PreparseDataConstants::kMessageArgCountPos);
int pos = PreparseDataConstants::kMessageTextPos;
for (unsigned int i = 0; i <= arg_count; i++) {
if (store_.length() <= PreparseDataConstants::kHeaderSize + pos) {
return false;
}
int length = static_cast<int>(Read(pos));
if (length < 0) return false;
pos += 1 + length;
}
if (store_.length() < PreparseDataConstants::kHeaderSize + pos) {
return false;
}
return true;
}
// Check that the space allocated for function entries is sane.
int functions_size =
static_cast<int>(store_[PreparseDataConstants::kFunctionsSizeOffset]);
if (functions_size < 0) return false;
if (functions_size % FunctionEntry::kSize != 0) return false;
// Check that the count of symbols is non-negative.
int symbol_count =
static_cast<int>(store_[PreparseDataConstants::kSymbolCountOffset]);
if (symbol_count < 0) return false;
// Check that the total size has room for header and function entries.
int minimum_size =
PreparseDataConstants::kHeaderSize + functions_size;
if (store_.length() < minimum_size) return false;
return true;
}
const char* ScriptDataImpl::ReadString(unsigned* start, int* chars) {
int length = start[0];
char* result = NewArray<char>(length + 1);
for (int i = 0; i < length; i++) {
result[i] = start[i + 1];
}
result[length] = '\0';
if (chars != NULL) *chars = length;
return result;
}
Scanner::Location ScriptDataImpl::MessageLocation() {
int beg_pos = Read(PreparseDataConstants::kMessageStartPos);
int end_pos = Read(PreparseDataConstants::kMessageEndPos);
return Scanner::Location(beg_pos, end_pos);
}
const char* ScriptDataImpl::BuildMessage() {
unsigned* start = ReadAddress(PreparseDataConstants::kMessageTextPos);
return ReadString(start, NULL);
}
Vector<const char*> ScriptDataImpl::BuildArgs() {
int arg_count = Read(PreparseDataConstants::kMessageArgCountPos);
const char** array = NewArray<const char*>(arg_count);
// Position after text found by skipping past length field and
// length field content words.
int pos = PreparseDataConstants::kMessageTextPos + 1
+ Read(PreparseDataConstants::kMessageTextPos);
for (int i = 0; i < arg_count; i++) {
int count = 0;
array[i] = ReadString(ReadAddress(pos), &count);
pos += count + 1;
}
return Vector<const char*>(array, arg_count);
}
unsigned ScriptDataImpl::Read(int position) {
return store_[PreparseDataConstants::kHeaderSize + position];
}
unsigned* ScriptDataImpl::ReadAddress(int position) {
return &store_[PreparseDataConstants::kHeaderSize + position];
}
Scope* Parser::NewScope(Scope* parent, Scope::Type type, bool inside_with) {
Scope* result = new(zone()) Scope(parent, type);
result->Initialize(inside_with);
return result;
}
// ----------------------------------------------------------------------------
// Target is a support class to facilitate manipulation of the
// Parser's target_stack_ (the stack of potential 'break' and
// 'continue' statement targets). Upon construction, a new target is
// added; it is removed upon destruction.
class Target BASE_EMBEDDED {
public:
Target(Target** variable, AstNode* node)
: variable_(variable), node_(node), previous_(*variable) {
*variable = this;
}
~Target() {
*variable_ = previous_;
}
Target* previous() { return previous_; }
AstNode* node() { return node_; }
private:
Target** variable_;
AstNode* node_;
Target* previous_;
};
class TargetScope BASE_EMBEDDED {
public:
explicit TargetScope(Target** variable)
: variable_(variable), previous_(*variable) {
*variable = NULL;
}
~TargetScope() {
*variable_ = previous_;
}
private:
Target** variable_;
Target* previous_;
};
// ----------------------------------------------------------------------------
// LexicalScope is a support class to facilitate manipulation of the
// Parser's scope stack. The constructor sets the parser's top scope
// to the incoming scope, and the destructor resets it.
//
// Additionally, it stores transient information used during parsing.
// These scopes are not kept around after parsing or referenced by syntax
// trees so they can be stack-allocated and hence used by the pre-parser.
class LexicalScope BASE_EMBEDDED {
public:
LexicalScope(Parser* parser, Scope* scope, Isolate* isolate);
~LexicalScope();
int NextMaterializedLiteralIndex() {
int next_index =
materialized_literal_count_ + JSFunction::kLiteralsPrefixSize;
materialized_literal_count_++;
return next_index;
}
int materialized_literal_count() { return materialized_literal_count_; }
void SetThisPropertyAssignmentInfo(
bool only_simple_this_property_assignments,
Handle<FixedArray> this_property_assignments) {
only_simple_this_property_assignments_ =
only_simple_this_property_assignments;
this_property_assignments_ = this_property_assignments;
}
bool only_simple_this_property_assignments() {
return only_simple_this_property_assignments_;
}
Handle<FixedArray> this_property_assignments() {
return this_property_assignments_;
}
void AddProperty() { expected_property_count_++; }
int expected_property_count() { return expected_property_count_; }
private:
// Captures the number of literals that need materialization in the
// function. Includes regexp literals, and boilerplate for object
// and array literals.
int materialized_literal_count_;
// Properties count estimation.
int expected_property_count_;
// Keeps track of assignments to properties of this. Used for
// optimizing constructors.
bool only_simple_this_property_assignments_;
Handle<FixedArray> this_property_assignments_;
// Bookkeeping
Parser* parser_;
// Previous values
LexicalScope* lexical_scope_parent_;
Scope* previous_scope_;
int previous_with_nesting_level_;
unsigned previous_ast_node_id_;
};
LexicalScope::LexicalScope(Parser* parser, Scope* scope, Isolate* isolate)
: materialized_literal_count_(0),
expected_property_count_(0),
only_simple_this_property_assignments_(false),
this_property_assignments_(isolate->factory()->empty_fixed_array()),
parser_(parser),
lexical_scope_parent_(parser->lexical_scope_),
previous_scope_(parser->top_scope_),
previous_with_nesting_level_(parser->with_nesting_level_),
previous_ast_node_id_(isolate->ast_node_id()) {
parser->top_scope_ = scope;
parser->lexical_scope_ = this;
parser->with_nesting_level_ = 0;
isolate->set_ast_node_id(AstNode::kFunctionEntryId + 1);
}
LexicalScope::~LexicalScope() {
parser_->top_scope_ = previous_scope_;
parser_->lexical_scope_ = lexical_scope_parent_;
parser_->with_nesting_level_ = previous_with_nesting_level_;
parser_->isolate()->set_ast_node_id(previous_ast_node_id_);
}
// ----------------------------------------------------------------------------
// 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 ok); \
if (!*ok) return NULL; \
((void)0
#define DUMMY ) // to make indentation work
#undef DUMMY
#define CHECK_FAILED /**/); \
if (failed_) return NULL; \
((void)0
#define DUMMY ) // to make indentation work
#undef DUMMY
// ----------------------------------------------------------------------------
// Implementation of Parser
Parser::Parser(Handle<Script> script,
bool allow_natives_syntax,
v8::Extension* extension,
ScriptDataImpl* pre_data)
: isolate_(script->GetIsolate()),
symbol_cache_(pre_data ? pre_data->symbol_count() : 0),
script_(script),
scanner_(isolate_->unicode_cache()),
top_scope_(NULL),
with_nesting_level_(0),
lexical_scope_(NULL),
target_stack_(NULL),
allow_natives_syntax_(allow_natives_syntax),
extension_(extension),
pre_data_(pre_data),
fni_(NULL),
stack_overflow_(false),
parenthesized_function_(false) {
AstNode::ResetIds();
}
FunctionLiteral* Parser::ParseProgram(Handle<String> source,
bool in_global_context,
StrictModeFlag strict_mode) {
ZoneScope zone_scope(isolate(), DONT_DELETE_ON_EXIT);
HistogramTimerScope timer(isolate()->counters()->parse());
isolate()->counters()->total_parse_size()->Increment(source->length());
fni_ = new(zone()) FuncNameInferrer(isolate());
// Initialize parser state.
source->TryFlatten();
if (source->IsExternalTwoByteString()) {
// Notice that the stream is destroyed at the end of the branch block.
// The last line of the blocks can't be moved outside, even though they're
// identical calls.
ExternalTwoByteStringUC16CharacterStream stream(
Handle<ExternalTwoByteString>::cast(source), 0, source->length());
scanner_.Initialize(&stream);
return DoParseProgram(source, in_global_context, strict_mode, &zone_scope);
} else {
GenericStringUC16CharacterStream stream(source, 0, source->length());
scanner_.Initialize(&stream);
return DoParseProgram(source, in_global_context, strict_mode, &zone_scope);
}
}
FunctionLiteral* Parser::DoParseProgram(Handle<String> source,
bool in_global_context,
StrictModeFlag strict_mode,
ZoneScope* zone_scope) {
ASSERT(target_stack_ == NULL);
if (pre_data_ != NULL) pre_data_->Initialize();
// Compute the parsing mode.
mode_ = FLAG_lazy ? PARSE_LAZILY : PARSE_EAGERLY;
if (allow_natives_syntax_ || extension_ != NULL) mode_ = PARSE_EAGERLY;
Scope::Type type =
in_global_context
? Scope::GLOBAL_SCOPE
: Scope::EVAL_SCOPE;
Handle<String> no_name = isolate()->factory()->empty_symbol();
FunctionLiteral* result = NULL;
{ Scope* scope = NewScope(top_scope_, type, inside_with());
LexicalScope lexical_scope(this, scope, isolate());
if (strict_mode == kStrictMode) {
top_scope_->EnableStrictMode();
}
ZoneList<Statement*>* body = new(zone()) ZoneList<Statement*>(16);
bool ok = true;
int beg_loc = scanner().location().beg_pos;
ParseSourceElements(body, Token::EOS, &ok);
if (ok && top_scope_->is_strict_mode()) {
CheckOctalLiteral(beg_loc, scanner().location().end_pos, &ok);
}
if (ok) {
result = new(zone()) FunctionLiteral(
isolate(),
no_name,
top_scope_,
body,
lexical_scope.materialized_literal_count(),
lexical_scope.expected_property_count(),
lexical_scope.only_simple_this_property_assignments(),
lexical_scope.this_property_assignments(),
0,
0,
source->length(),
FunctionLiteral::ANONYMOUS_EXPRESSION,
false); // Does not have duplicate parameters.
} else if (stack_overflow_) {
isolate()->StackOverflow();
}
}
// Make sure the target stack is empty.
ASSERT(target_stack_ == NULL);
// If there was a syntax error we have to get rid of the AST
// and it is not safe to do so before the scope has been deleted.
if (result == NULL) zone_scope->DeleteOnExit();
return result;
}
FunctionLiteral* Parser::ParseLazy(CompilationInfo* info) {
ZoneScope zone_scope(isolate(), DONT_DELETE_ON_EXIT);
HistogramTimerScope timer(isolate()->counters()->parse_lazy());
Handle<String> source(String::cast(script_->source()));
isolate()->counters()->total_parse_size()->Increment(source->length());
Handle<SharedFunctionInfo> shared_info = info->shared_info();
// Initialize parser state.
source->TryFlatten();
if (source->IsExternalTwoByteString()) {
ExternalTwoByteStringUC16CharacterStream stream(
Handle<ExternalTwoByteString>::cast(source),
shared_info->start_position(),
shared_info->end_position());
FunctionLiteral* result = ParseLazy(info, &stream, &zone_scope);
return result;
} else {
GenericStringUC16CharacterStream stream(source,
shared_info->start_position(),
shared_info->end_position());
FunctionLiteral* result = ParseLazy(info, &stream, &zone_scope);
return result;
}
}
FunctionLiteral* Parser::ParseLazy(CompilationInfo* info,
UC16CharacterStream* source,
ZoneScope* zone_scope) {
Handle<SharedFunctionInfo> shared_info = info->shared_info();
scanner_.Initialize(source);
ASSERT(target_stack_ == NULL);
Handle<String> name(String::cast(shared_info->name()));
fni_ = new(zone()) FuncNameInferrer(isolate());
fni_->PushEnclosingName(name);
mode_ = PARSE_EAGERLY;
// Place holder for the result.
FunctionLiteral* result = NULL;
{
// Parse the function literal.
Scope* scope = NewScope(top_scope_, Scope::GLOBAL_SCOPE, inside_with());
if (!info->closure().is_null()) {
scope = Scope::DeserializeScopeChain(info, scope);
}
LexicalScope lexical_scope(this, scope, isolate());
if (shared_info->strict_mode()) {
top_scope_->EnableStrictMode();
}
FunctionLiteral::Type type = shared_info->is_expression()
? (shared_info->is_anonymous()
? FunctionLiteral::ANONYMOUS_EXPRESSION
: FunctionLiteral::NAMED_EXPRESSION)
: FunctionLiteral::DECLARATION;
bool ok = true;
result = ParseFunctionLiteral(name,
false, // Strict mode name already checked.
RelocInfo::kNoPosition,
type,
&ok);
// Make sure the results agree.
ASSERT(ok == (result != NULL));
}
// Make sure the target stack is empty.
ASSERT(target_stack_ == NULL);
// If there was a stack overflow we have to get rid of AST and it is
// not safe to do before scope has been deleted.
if (result == NULL) {
zone_scope->DeleteOnExit();
if (stack_overflow_) isolate()->StackOverflow();
} else {
Handle<String> inferred_name(shared_info->inferred_name());
result->set_inferred_name(inferred_name);
}
return result;
}
Handle<String> Parser::GetSymbol(bool* ok) {
int symbol_id = -1;
if (pre_data() != NULL) {
symbol_id = pre_data()->GetSymbolIdentifier();
}
return LookupSymbol(symbol_id);
}
void Parser::ReportMessage(const char* type, Vector<const char*> args) {
Scanner::Location source_location = scanner().location();
ReportMessageAt(source_location, type, args);
}
void Parser::ReportMessageAt(Scanner::Location source_location,
const char* type,
Vector<const char*> args) {
MessageLocation location(script_,
source_location.beg_pos,
source_location.end_pos);
Factory* factory = isolate()->factory();
Handle<FixedArray> elements = factory->NewFixedArray(args.length());
for (int i = 0; i < args.length(); i++) {
Handle<String> arg_string = factory->NewStringFromUtf8(CStrVector(args[i]));
elements->set(i, *arg_string);
}
Handle<JSArray> array = factory->NewJSArrayWithElements(elements);
Handle<Object> result = factory->NewSyntaxError(type, array);
isolate()->Throw(*result, &location);
}
void Parser::ReportMessageAt(Scanner::Location source_location,
const char* type,
Vector<Handle<String> > args) {
MessageLocation location(script_,
source_location.beg_pos,
source_location.end_pos);
Factory* factory = isolate()->factory();
Handle<FixedArray> elements = factory->NewFixedArray(args.length());
for (int i = 0; i < args.length(); i++) {
elements->set(i, *args[i]);
}
Handle<JSArray> array = factory->NewJSArrayWithElements(elements);
Handle<Object> result = factory->NewSyntaxError(type, array);
isolate()->Throw(*result, &location);
}
// Base class containing common code for the different finder classes used by
// the parser.
class ParserFinder {
protected:
ParserFinder() {}
static Assignment* AsAssignment(Statement* stat) {
if (stat == NULL) return NULL;
ExpressionStatement* exp_stat = stat->AsExpressionStatement();
if (exp_stat == NULL) return NULL;
return exp_stat->expression()->AsAssignment();
}
};
// An InitializationBlockFinder finds and marks sequences of statements of the
// form expr.a = ...; expr.b = ...; etc.
class InitializationBlockFinder : public ParserFinder {
public:
// We find and mark the initialization blocks in top level
// non-looping code only. This is because the optimization prevents
// reuse of the map transitions, so it should be used only for code
// that will only be run once.
InitializationBlockFinder(Scope* top_scope, Target* target)
: enabled_(top_scope->DeclarationScope()->is_global_scope() &&
!IsLoopTarget(target)),
first_in_block_(NULL),
last_in_block_(NULL),
block_size_(0) {}
~InitializationBlockFinder() {
if (!enabled_) return;
if (InBlock()) EndBlock();
}
void Update(Statement* stat) {
if (!enabled_) return;
Assignment* assignment = AsAssignment(stat);
if (InBlock()) {
if (BlockContinues(assignment)) {
UpdateBlock(assignment);
} else {
EndBlock();
}
}
if (!InBlock() && (assignment != NULL) &&
(assignment->op() == Token::ASSIGN)) {
StartBlock(assignment);
}
}
private:
// The minimum number of contiguous assignment that will
// be treated as an initialization block. Benchmarks show that
// the overhead exceeds the savings below this limit.
static const int kMinInitializationBlock = 3;
static bool IsLoopTarget(Target* target) {
while (target != NULL) {
if (target->node()->AsIterationStatement() != NULL) return true;
target = target->previous();
}
return false;
}
// Returns true if the expressions appear to denote the same object.
// In the context of initialization blocks, we only consider expressions
// of the form 'expr.x' or expr["x"].
static bool SameObject(Expression* e1, Expression* e2) {
VariableProxy* v1 = e1->AsVariableProxy();
VariableProxy* v2 = e2->AsVariableProxy();
if (v1 != NULL && v2 != NULL) {
return v1->name()->Equals(*v2->name());
}
Property* p1 = e1->AsProperty();
Property* p2 = e2->AsProperty();
if ((p1 == NULL) || (p2 == NULL)) return false;
Literal* key1 = p1->key()->AsLiteral();
Literal* key2 = p2->key()->AsLiteral();
if ((key1 == NULL) || (key2 == NULL)) return false;
if (!key1->handle()->IsString() || !key2->handle()->IsString()) {
return false;
}
String* name1 = String::cast(*key1->handle());
String* name2 = String::cast(*key2->handle());
if (!name1->Equals(name2)) return false;
return SameObject(p1->obj(), p2->obj());
}
// Returns true if the expressions appear to denote different properties
// of the same object.
static bool PropertyOfSameObject(Expression* e1, Expression* e2) {
Property* p1 = e1->AsProperty();
Property* p2 = e2->AsProperty();
if ((p1 == NULL) || (p2 == NULL)) return false;
return SameObject(p1->obj(), p2->obj());
}
bool BlockContinues(Assignment* assignment) {
if ((assignment == NULL) || (first_in_block_ == NULL)) return false;
if (assignment->op() != Token::ASSIGN) return false;
return PropertyOfSameObject(first_in_block_->target(),
assignment->target());
}
void StartBlock(Assignment* assignment) {
first_in_block_ = assignment;
last_in_block_ = assignment;
block_size_ = 1;
}
void UpdateBlock(Assignment* assignment) {
last_in_block_ = assignment;
++block_size_;
}
void EndBlock() {
if (block_size_ >= kMinInitializationBlock) {
first_in_block_->mark_block_start();
last_in_block_->mark_block_end();
}
last_in_block_ = first_in_block_ = NULL;
block_size_ = 0;
}
bool InBlock() { return first_in_block_ != NULL; }
const bool enabled_;
Assignment* first_in_block_;
Assignment* last_in_block_;
int block_size_;
DISALLOW_COPY_AND_ASSIGN(InitializationBlockFinder);
};
// A ThisNamedPropertyAssigmentFinder finds and marks statements of the form
// this.x = ...;, where x is a named property. It also determines whether a
// function contains only assignments of this type.
class ThisNamedPropertyAssigmentFinder : public ParserFinder {
public:
explicit ThisNamedPropertyAssigmentFinder(Isolate* isolate)
: isolate_(isolate),
only_simple_this_property_assignments_(true),
names_(NULL),
assigned_arguments_(NULL),
assigned_constants_(NULL) {}
void Update(Scope* scope, Statement* stat) {
// Bail out if function already has property assignment that are
// not simple this property assignments.
if (!only_simple_this_property_assignments_) {
return;
}
// Check whether this statement is of the form this.x = ...;
Assignment* assignment = AsAssignment(stat);
if (IsThisPropertyAssignment(assignment)) {
HandleThisPropertyAssignment(scope, assignment);
} else {
only_simple_this_property_assignments_ = false;
}
}
// Returns whether only statements of the form this.x = y; where y is either a
// constant or a function argument was encountered.
bool only_simple_this_property_assignments() {
return only_simple_this_property_assignments_;
}
// Returns a fixed array containing three elements for each assignment of the
// form this.x = y;
Handle<FixedArray> GetThisPropertyAssignments() {
if (names_ == NULL) {
return isolate_->factory()->empty_fixed_array();
}
ASSERT(names_ != NULL);
ASSERT(assigned_arguments_ != NULL);
ASSERT_EQ(names_->length(), assigned_arguments_->length());
ASSERT_EQ(names_->length(), assigned_constants_->length());
Handle<FixedArray> assignments =
isolate_->factory()->NewFixedArray(names_->length() * 3);
for (int i = 0; i < names_->length(); i++) {
assignments->set(i * 3, *names_->at(i));
assignments->set(i * 3 + 1, Smi::FromInt(assigned_arguments_->at(i)));
assignments->set(i * 3 + 2, *assigned_constants_->at(i));
}
return assignments;
}