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[dart2wasm] Port VM JSON parsing improvements

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This ports https://dart-review.googlesource.com/c/sdk/+/365803 to dart2wasm.

Benchmarks: https://golem.corp.goog/Revision?repository=dart&revision=110551&patch=19222

Change-Id: Id4a8e0f44abcde3552c50605d9b329443d43d1d5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/370821
Commit-Queue: Ömer Ağacan <omersa@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
This commit is contained in:
Ömer Sinan Ağacan 2024-06-11 16:10:23 +00:00 committed by Commit Queue
parent d96ff605e2
commit 455d85f528
2 changed files with 128 additions and 25 deletions
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143
sdk/lib/_internal/wasm/lib/convert_patch.dart
View file

@ -103,7 +103,7 @@ class _JsonListener {
void popContainer() {
value = currentContainer;
currentContainer = stack.removeLast();
if (currentContainer is Map) key = stack.removeLast() as String;
if (currentContainer is Map) key = unsafeCast<String>(stack.removeLast());
}
void handleString(String value) {
@ -128,12 +128,12 @@ class _JsonListener {
}
void propertyName() {
key = value as String;
key = unsafeCast<String>(value);
value = null;
}
void propertyValue() {
var map = currentContainer as Map;
var map = unsafeCast<Map>(currentContainer);
var reviver = this.reviver;
if (reviver != null) {
value = reviver(key, value);
@ -153,7 +153,7 @@ class _JsonListener {
}
void arrayElement() {
var list = currentContainer as List;
var list = unsafeCast<List>(currentContainer);
var reviver = this.reviver;
if (reviver != null) {
value = reviver(list.length, value);
@ -524,6 +524,13 @@ mixin _ChunkedJsonParser<T> on _JsonParserWithListener {
*/
int getChar(int index);
/**
* Returns [true] if [getChar] is returning UTF16 code units.
*
* Otherwise it is expected that [getChar] is returning UTF8 bytes.
*/
bool get isUtf16Input;
/**
* Copy ASCII characters from start to end of chunk into a list.
*
@ -808,16 +815,30 @@ mixin _ChunkedJsonParser<T> on _JsonParserWithListener {
position = parsePartial(position);
if (position == length) return;
}
final OneByteString charAttributes =
unsafeCast<OneByteString>(_characterAttributes);
int state = this.state;
outer:
while (position < length) {
int char = getChar(position);
switch (char) {
case SPACE:
case CARRIAGE_RETURN:
case NEWLINE:
case TAB:
position++;
int char = 0;
do {
char = getChar(position);
if (isUtf16Input && char > 0xFF) {
break;
}
if ((oneByteStringCodeUnitAtUnchecked(charAttributes, char) &
CHAR_WHITESPACE) ==
0) {
break;
}
position++;
if (position >= length) {
break outer;
}
} while (true);
switch (char) {
case QUOTE:
if ((state & ALLOW_STRING_MASK) != 0) fail(position);
state |= VALUE_READ_BITS;
@ -977,6 +998,37 @@ mixin _ChunkedJsonParser<T> on _JsonParserWithListener {
return length;
}
static const int CHAR_SIMPLE_STRING_END = 1;
static const int CHAR_WHITESPACE = 2;
/**
* [_characterAttributes] string was generated using the following code:
*
* ```
* int $(String ch) => ch.codeUnitAt(0);
* final list = Uint8List(256);
* for (var i = 0; i < $(' '); i++) {
* list[i] |= CHAR_SIMPLE_STRING_END;
* }
* list[$('"')] |= CHAR_SIMPLE_STRING_END;
* list[$('\\')] |= CHAR_SIMPLE_STRING_END;
* list[$(' ')] |= CHAR_WHITESPACE;
* list[$('\r')] |= CHAR_WHITESPACE;
* list[$('\n')] |= CHAR_WHITESPACE;
* list[$('\t')] |= CHAR_WHITESPACE;
* for (var i = 0; i < 256; i += 64) {
* print("'${String.fromCharCodes([
* for (var v in list.skip(i).take(64)) v + $(' '),
* ])}'");
* }
* ```
*/
static const String _characterAttributes =
'!!!!!!!!!##!!#!!!!!!!!!!!!!!!!!!" ! '
' ! '
' '
' ';
/**
* Parses a string value.
*
@ -984,28 +1036,43 @@ mixin _ChunkedJsonParser<T> on _JsonParserWithListener {
* Returned position right after the final quote.
*/
int parseString(int position) {
final OneByteString charAttributes =
unsafeCast<OneByteString>(_characterAttributes);
// Format: '"'([^\x00-\x1f\\\"]|'\\'[bfnrt/\\"])*'"'
// Initial position is right after first '"'.
int start = position;
int end = chunkEnd;
int bits = 0;
while (position < end) {
int char = getChar(position++);
bits |= char; // Includes final '"', but that never matters.
// BACKSLASH is larger than QUOTE and SPACE.
if (char > BACKSLASH) {
continue;
int char = 0;
if (position < end) {
do {
// Caveat: do not combine the following two lines together. It helps
// compiler to generate better code (it currently can't reorder operations
// to reduce register pressure).
char = getChar(position);
position++;
bits |= char; // Includes final '"', but that never matters.
if (isUtf16Input && char > 0xFF) {
continue;
}
if ((oneByteStringCodeUnitAtUnchecked(charAttributes, char) &
CHAR_SIMPLE_STRING_END) !=
0) {
break;
}
} while (position < end);
if (char == QUOTE) {
int sliceEnd = position - 1;
listener.handleString(getString(start, sliceEnd, bits));
return sliceEnd + 1;
}
if (char == BACKSLASH) {
beginString();
int sliceEnd = position - 1;
beginString();
if (start < sliceEnd) addSliceToString(start, sliceEnd);
return parseStringToBuffer(sliceEnd);
}
if (char == QUOTE) {
listener.handleString(getString(start, position - 1, bits));
return position;
}
if (char < SPACE) {
fail(position - 1, "Control character in string");
}
@ -1055,6 +1122,9 @@ mixin _ChunkedJsonParser<T> on _JsonParserWithListener {
* slices of non-escape characters using [addSliceToString].
*/
int parseStringToBuffer(int position) {
final OneByteString charAttributes =
unsafeCast<OneByteString>(_characterAttributes);
int end = chunkEnd;
int start = position;
while (true) {
@ -1064,11 +1134,25 @@ mixin _ChunkedJsonParser<T> on _JsonParserWithListener {
}
return chunkString(STR_PLAIN);
}
int char = getChar(position++);
if (char > BACKSLASH) continue;
int char = 0;
do {
char = getChar(position);
position++;
if (isUtf16Input && char > 0xFF) {
continue;
}
if ((oneByteStringCodeUnitAtUnchecked(charAttributes, char) &
CHAR_SIMPLE_STRING_END) !=
0) {
break;
}
} while (position < end);
if (char < SPACE) {
fail(position - 1); // Control character in string.
}
if (char == QUOTE) {
int quotePosition = position - 1;
if (quotePosition > start) {
@ -1077,13 +1161,16 @@ mixin _ChunkedJsonParser<T> on _JsonParserWithListener {
listener.handleString(endString());
return position;
}
if (char != BACKSLASH) {
continue;
}
// Handle escape.
if (position - 1 > start) {
addSliceToString(start, position - 1);
}
if (position == end) return chunkString(STR_ESCAPE);
position = parseStringEscape(position);
if (position == end) return position;
@ -1379,6 +1466,9 @@ class _JsonStringParser extends _JsonParserWithListener
_JsonStringParser(_JsonListener listener) : super(listener);
@pragma('wasm:prefer-inline')
bool get isUtf16Input => true;
int getChar(int position) => chunk.codeUnitAt(position);
String getString(int start, int end, int bits) {
@ -1500,13 +1590,16 @@ class _JsonUtf8Parser extends _JsonParserWithListener
parse(start);
}
@pragma('wasm:prefer-inline')
bool get isUtf16Input => false;
@pragma('wasm:prefer-inline')
int getChar(int position) => chunk[position];
String getString(int start, int end, int bits) {
const int maxAsciiChar = 0x7f;
if (bits <= maxAsciiChar) {
return new String.fromCharCodes(chunk, start, end);
return createOneByteStringFromCharacters(chunk, start, end);
}
beginString();
if (start < end) addSliceToString(start, end);

10
sdk/lib/_internal/wasm/lib/string.dart
View file

@ -17,6 +17,7 @@ import 'dart:_js_helper' show JS, jsStringToDartString;
import 'dart:_js_types' show JSStringImpl;
import 'dart:_object_helper';
import 'dart:_string_helper';
import 'dart:_typed_data';
import 'dart:_wasm';
import "dart:typed_data" show Uint8List, Uint16List;
@ -52,6 +53,15 @@ void copyRangeFromUint8ListToOneByteString(
}
}
@pragma("wasm:prefer-inline")
OneByteString createOneByteStringFromCharacters(
U8List bytes, int start, int end) {
final len = end - start;
final s = OneByteString.withLength(len);
s._array.copy(0, bytes.data, start, len);
return s;
}
extension OneByteStringUnsafeExtensions on String {
@pragma('wasm:prefer-inline')
int oneByteStringCodeUnitAtUnchecked(int index) =>