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LibJS: Reduce copying of string data in RegExp.prototype

In addition to invoking js_string() with existing UTF-16 strings when
possible, RegExpExec now takes a Utf16String instead of a Utf16View. The
view was previously fully copied into the returned result object, so
this prevents potentially large copies of string data.
This commit is contained in:
Timothy Flynn 2021-08-09 12:55:08 -04:00 committed by Andreas Kling
parent 6c45620709
commit 34bd25f6c2
4 changed files with 39 additions and 49 deletions

View file

@ -18,7 +18,6 @@
#include <LibJS/Runtime/RegExpPrototype.h> #include <LibJS/Runtime/RegExpPrototype.h>
#include <LibJS/Runtime/RegExpStringIterator.h> #include <LibJS/Runtime/RegExpStringIterator.h>
#include <LibJS/Runtime/StringPrototype.h> #include <LibJS/Runtime/StringPrototype.h>
#include <LibJS/Runtime/Utf16String.h>
#include <LibJS/Token.h> #include <LibJS/Token.h>
namespace JS { namespace JS {
@ -194,7 +193,7 @@ static Value make_indices_array(GlobalObject& global_object, Utf16View const& st
} }
// 22.2.5.2.2 RegExpBuiltinExec ( R, S ), https://tc39.es/ecma262/#sec-regexpbuiltinexec // 22.2.5.2.2 RegExpBuiltinExec ( R, S ), https://tc39.es/ecma262/#sec-regexpbuiltinexec
static Value regexp_builtin_exec(GlobalObject& global_object, RegExpObject& regexp_object, Utf16View const& string) static Value regexp_builtin_exec(GlobalObject& global_object, RegExpObject& regexp_object, Utf16String string)
{ {
// FIXME: This should try using internal slots [[RegExpMatcher]], [[OriginalFlags]], etc. // FIXME: This should try using internal slots [[RegExpMatcher]], [[OriginalFlags]], etc.
auto& vm = global_object.vm(); auto& vm = global_object.vm();
@ -215,6 +214,7 @@ static Value regexp_builtin_exec(GlobalObject& global_object, RegExpObject& rege
if (!global && !sticky) if (!global && !sticky)
last_index = 0; last_index = 0;
auto string_view = string.view();
RegexResult result; RegexResult result;
while (true) { while (true) {
@ -228,8 +228,8 @@ static Value regexp_builtin_exec(GlobalObject& global_object, RegExpObject& rege
return js_null(); return js_null();
} }
regex.start_offset = unicode ? string.code_point_offset_of(last_index) : last_index; regex.start_offset = unicode ? string_view.code_point_offset_of(last_index) : last_index;
result = regex.match(string); result = regex.match(string_view);
if (result.success) if (result.success)
break; break;
@ -242,7 +242,7 @@ static Value regexp_builtin_exec(GlobalObject& global_object, RegExpObject& rege
return js_null(); return js_null();
} }
last_index = advance_string_index(string, last_index, unicode); last_index = advance_string_index(string_view, last_index, unicode);
} }
auto& match = result.matches[0]; auto& match = result.matches[0];
@ -253,8 +253,8 @@ static Value regexp_builtin_exec(GlobalObject& global_object, RegExpObject& rege
auto end_index = match_index + match.view.length(); auto end_index = match_index + match.view.length();
if (unicode) { if (unicode) {
match_index = string.code_unit_offset_of(match.global_offset); match_index = string_view.code_unit_offset_of(match.global_offset);
end_index = string.code_unit_offset_of(end_index); end_index = string_view.code_unit_offset_of(end_index);
} }
if (global || sticky) { if (global || sticky) {
@ -267,10 +267,6 @@ static Value regexp_builtin_exec(GlobalObject& global_object, RegExpObject& rege
if (vm.exception()) if (vm.exception())
return {}; return {};
array->create_data_property_or_throw(vm.names.index, Value(match_index));
array->create_data_property_or_throw(vm.names.input, js_string(vm, string));
array->create_data_property_or_throw(0, js_string(vm, match.view.u16_view()));
Vector<Optional<Match>> indices { Match::create(match) }; Vector<Optional<Match>> indices { Match::create(match) };
HashMap<String, Match> group_names; HashMap<String, Match> group_names;
@ -303,17 +299,21 @@ static Value regexp_builtin_exec(GlobalObject& global_object, RegExpObject& rege
array->create_data_property_or_throw(vm.names.groups, groups); array->create_data_property_or_throw(vm.names.groups, groups);
if (has_indices) { if (has_indices) {
auto indices_array = make_indices_array(global_object, string, indices, group_names, has_groups); auto indices_array = make_indices_array(global_object, string_view, indices, group_names, has_groups);
array->create_data_property(vm.names.indices, indices_array); array->create_data_property(vm.names.indices, indices_array);
if (vm.exception()) if (vm.exception())
return {}; return {};
} }
array->create_data_property_or_throw(vm.names.index, Value(match_index));
array->create_data_property_or_throw(vm.names.input, js_string(vm, move(string)));
array->create_data_property_or_throw(0, js_string(vm, match.view.u16_view()));
return array; return array;
} }
// 22.2.5.2.1 RegExpExec ( R, S ), https://tc39.es/ecma262/#sec-regexpexec // 22.2.5.2.1 RegExpExec ( R, S ), https://tc39.es/ecma262/#sec-regexpexec
Value regexp_exec(GlobalObject& global_object, Object& regexp_object, Utf16View const& string) Value regexp_exec(GlobalObject& global_object, Object& regexp_object, Utf16String string)
{ {
auto& vm = global_object.vm(); auto& vm = global_object.vm();
@ -322,7 +322,7 @@ Value regexp_exec(GlobalObject& global_object, Object& regexp_object, Utf16View
return {}; return {};
if (exec.is_function()) { if (exec.is_function()) {
auto result = vm.call(exec.as_function(), &regexp_object, js_string(vm, string)); auto result = vm.call(exec.as_function(), &regexp_object, js_string(vm, move(string)));
if (vm.exception()) if (vm.exception())
return {}; return {};
@ -337,7 +337,7 @@ Value regexp_exec(GlobalObject& global_object, Object& regexp_object, Utf16View
return {}; return {};
} }
return regexp_builtin_exec(global_object, static_cast<RegExpObject&>(regexp_object), string); return regexp_builtin_exec(global_object, static_cast<RegExpObject&>(regexp_object), move(string));
} }
// 1.1.4.3 get RegExp.prototype.hasIndices, https://tc39.es/proposal-regexp-match-indices/#sec-get-regexp.prototype.hasIndices // 1.1.4.3 get RegExp.prototype.hasIndices, https://tc39.es/proposal-regexp-match-indices/#sec-get-regexp.prototype.hasIndices
@ -415,9 +415,8 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::exec)
auto string = vm.argument(0).to_utf16_string(global_object); auto string = vm.argument(0).to_utf16_string(global_object);
if (vm.exception()) if (vm.exception())
return {}; return {};
auto string_view = string.view();
return regexp_builtin_exec(global_object, *regexp_object, string_view); return regexp_builtin_exec(global_object, *regexp_object, move(string));
} }
// 22.2.5.15 RegExp.prototype.test ( S ), https://tc39.es/ecma262/#sec-regexp.prototype.test // 22.2.5.15 RegExp.prototype.test ( S ), https://tc39.es/ecma262/#sec-regexp.prototype.test
@ -430,9 +429,8 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::test)
auto string = vm.argument(0).to_utf16_string(global_object); auto string = vm.argument(0).to_utf16_string(global_object);
if (vm.exception()) if (vm.exception())
return {}; return {};
auto string_view = string.view();
auto match = regexp_exec(global_object, *regexp_object, string_view); auto match = regexp_exec(global_object, *regexp_object, move(string));
if (vm.exception()) if (vm.exception())
return {}; return {};
@ -473,7 +471,6 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::symbol_match)
auto string = vm.argument(0).to_utf16_string(global_object); auto string = vm.argument(0).to_utf16_string(global_object);
if (vm.exception()) if (vm.exception())
return {}; return {};
auto string_view = string.view();
auto global_value = regexp_object->get(vm.names.global); auto global_value = regexp_object->get(vm.names.global);
if (vm.exception()) if (vm.exception())
@ -481,7 +478,7 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::symbol_match)
bool global = global_value.to_boolean(); bool global = global_value.to_boolean();
if (!global) { if (!global) {
auto result = regexp_exec(global_object, *regexp_object, string_view); auto result = regexp_exec(global_object, *regexp_object, move(string));
if (vm.exception()) if (vm.exception())
return {}; return {};
return result; return result;
@ -503,7 +500,7 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::symbol_match)
size_t n = 0; size_t n = 0;
while (true) { while (true) {
auto result = regexp_exec(global_object, *regexp_object, string_view); auto result = regexp_exec(global_object, *regexp_object, string);
if (vm.exception()) if (vm.exception())
return {}; return {};
@ -528,7 +525,7 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::symbol_match)
return {}; return {};
if (match_str.is_empty()) { if (match_str.is_empty()) {
increment_last_index(global_object, *regexp_object, string_view, unicode); increment_last_index(global_object, *regexp_object, string.view(), unicode);
if (vm.exception()) if (vm.exception())
return {}; return {};
} }
@ -631,7 +628,7 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::symbol_replace)
MarkedValueList results(vm.heap()); MarkedValueList results(vm.heap());
while (true) { while (true) {
auto result = regexp_exec(global_object, *regexp_object, string_view); auto result = regexp_exec(global_object, *regexp_object, string);
if (vm.exception()) if (vm.exception())
return {}; return {};
if (result.is_null()) if (result.is_null())
@ -659,7 +656,7 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::symbol_replace)
} }
} }
String accumulated_result; StringBuilder accumulated_result;
size_t next_source_position = 0; size_t next_source_position = 0;
for (auto& result_value : results) { for (auto& result_value : results) {
@ -683,7 +680,7 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::symbol_replace)
if (vm.exception()) if (vm.exception())
return {}; return {};
position = clamp(position, static_cast<double>(0), static_cast<double>(string_view.length_in_code_units())); position = clamp(position, static_cast<double>(0), static_cast<double>(string.length_in_code_units()));
MarkedValueList captures(vm.heap()); MarkedValueList captures(vm.heap());
for (size_t n = 1; n <= n_captures; ++n) { for (size_t n = 1; n <= n_captures; ++n) {
@ -715,7 +712,7 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::symbol_replace)
replacer_args.append(js_string(vm, move(matched))); replacer_args.append(js_string(vm, move(matched)));
replacer_args.extend(move(captures)); replacer_args.extend(move(captures));
replacer_args.append(Value(position)); replacer_args.append(Value(position));
replacer_args.append(js_string(vm, string_view)); replacer_args.append(js_string(vm, string));
if (!named_captures.is_undefined()) { if (!named_captures.is_undefined()) {
replacer_args.append(move(named_captures)); replacer_args.append(move(named_captures));
} }
@ -742,27 +739,20 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::symbol_replace)
if (position >= next_source_position) { if (position >= next_source_position) {
auto substring = string_view.substring_view(next_source_position, position - next_source_position); auto substring = string_view.substring_view(next_source_position, position - next_source_position);
accumulated_result.append(substring);
accumulated_result.append(replacement);
StringBuilder builder;
builder.append(accumulated_result);
builder.append(substring.to_utf8(Utf16View::AllowInvalidCodeUnits::Yes));
builder.append(replacement);
accumulated_result = builder.build();
next_source_position = position + matched_length; next_source_position = position + matched_length;
} }
} }
if (next_source_position >= string_view.length_in_code_units()) if (next_source_position >= string.length_in_code_units())
return js_string(vm, accumulated_result); return js_string(vm, accumulated_result.build());
auto substring = string_view.substring_view(next_source_position); auto substring = string_view.substring_view(next_source_position);
accumulated_result.append(substring);
StringBuilder builder; return js_string(vm, accumulated_result.build());
builder.append(accumulated_result);
builder.append(substring.to_utf8(Utf16View::AllowInvalidCodeUnits::Yes));
return js_string(vm, builder.build());
} }
// 22.2.5.11 RegExp.prototype [ @@search ] ( string ), https://tc39.es/ecma262/#sec-regexp.prototype-@@search // 22.2.5.11 RegExp.prototype [ @@search ] ( string ), https://tc39.es/ecma262/#sec-regexp.prototype-@@search
@ -775,7 +765,6 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::symbol_search)
auto string = vm.argument(0).to_utf16_string(global_object); auto string = vm.argument(0).to_utf16_string(global_object);
if (vm.exception()) if (vm.exception())
return {}; return {};
auto string_view = string.view();
auto previous_last_index = regexp_object->get(vm.names.lastIndex); auto previous_last_index = regexp_object->get(vm.names.lastIndex);
if (vm.exception()) if (vm.exception())
@ -786,7 +775,7 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::symbol_search)
return {}; return {};
} }
auto result = regexp_exec(global_object, *regexp_object, string_view); auto result = regexp_exec(global_object, *regexp_object, move(string));
if (vm.exception()) if (vm.exception())
return {}; return {};
@ -862,12 +851,12 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::symbol_split)
if (limit == 0) if (limit == 0)
return array; return array;
if (string_view.is_empty()) { if (string.is_empty()) {
auto result = regexp_exec(global_object, *splitter, string_view); auto result = regexp_exec(global_object, *splitter, string);
if (!result.is_null()) if (!result.is_null())
return array; return array;
array->create_data_property_or_throw(0, js_string(vm, string_view)); array->create_data_property_or_throw(0, js_string(vm, move(string)));
return array; return array;
} }
@ -879,7 +868,7 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::symbol_split)
if (vm.exception()) if (vm.exception())
return {}; return {};
auto result = regexp_exec(global_object, *splitter, string_view); auto result = regexp_exec(global_object, *splitter, string);
if (vm.exception()) if (vm.exception())
return {}; return {};
if (result.is_null()) { if (result.is_null()) {

View file

@ -7,10 +7,11 @@
#pragma once #pragma once
#include <LibJS/Runtime/RegExpObject.h> #include <LibJS/Runtime/RegExpObject.h>
#include <LibJS/Runtime/Utf16String.h>
namespace JS { namespace JS {
Value regexp_exec(GlobalObject& global_object, Object& regexp_object, Utf16View const& string); Value regexp_exec(GlobalObject& global_object, Object& regexp_object, Utf16String string);
size_t advance_string_index(Utf16View const& string, size_t index, bool unicode); size_t advance_string_index(Utf16View const& string, size_t index, bool unicode);
class RegExpPrototype final : public Object { class RegExpPrototype final : public Object {

View file

@ -22,7 +22,7 @@ public:
virtual ~RegExpStringIterator() override = default; virtual ~RegExpStringIterator() override = default;
Object& regexp_object() { return m_regexp_object; } Object& regexp_object() { return m_regexp_object; }
Utf16View string() const { return m_string.view(); } Utf16String string() const { return m_string; }
bool global() const { return m_global; } bool global() const { return m_global; }
bool unicode() const { return m_unicode; } bool unicode() const { return m_unicode; }

View file

@ -76,7 +76,7 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpStringIteratorPrototype::next)
if (vm.exception()) if (vm.exception())
return {}; return {};
last_index = advance_string_index(iterator.string(), last_index, iterator.unicode()); last_index = advance_string_index(iterator.string().view(), last_index, iterator.unicode());
iterator.regexp_object().set(vm.names.lastIndex, Value(last_index), Object::ShouldThrowExceptions::Yes); iterator.regexp_object().set(vm.names.lastIndex, Value(last_index), Object::ShouldThrowExceptions::Yes);
if (vm.exception()) if (vm.exception())