Move quoting of a JSON string to a specialized runtime function.
Previously used string replace regexp with function replacement. Review URL: http://codereview.chromium.org/5443001 git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5909 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
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lrn@chromium.org
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30
src/json.js
30
src/json.js
@ -66,34 +66,10 @@ function JSONParse(text, reviver) {
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}
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}
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var characterQuoteCache = {
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'\b': '\\b', // ASCII 8, Backspace
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'\t': '\\t', // ASCII 9, Tab
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'\n': '\\n', // ASCII 10, Newline
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'\f': '\\f', // ASCII 12, Formfeed
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'\r': '\\r', // ASCII 13, Carriage Return
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'\"': '\\"',
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'\\': '\\\\'
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};
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function QuoteSingleJSONCharacter(c) {
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if (c in characterQuoteCache) {
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return characterQuoteCache[c];
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}
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var charCode = c.charCodeAt(0);
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var result;
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if (charCode < 16) result = '\\u000';
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else if (charCode < 256) result = '\\u00';
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else if (charCode < 4096) result = '\\u0';
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else result = '\\u';
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result += charCode.toString(16);
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characterQuoteCache[c] = result;
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return result;
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}
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function QuoteJSONString(str) {
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var quotable = /[\\\"\x00-\x1f]/g;
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return '"' + str.replace(quotable, QuoteSingleJSONCharacter) + '"';
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var quoted_str = %QuoteJSONString(str);
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if (IS_STRING(quoted_str)) return quoted_str;
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return '"' + str + '"';
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}
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function StackContains(stack, val) {
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161
src/runtime.cc
161
src/runtime.cc
@ -4521,6 +4521,167 @@ static MaybeObject* Runtime_URIUnescape(Arguments args) {
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}
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static const char* const JsonQuotes[128] = {
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"\\u0000", "\\u0001", "\\u0002", "\\u0003",
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"\\u0004", "\\u0005", "\\u0006", "\\u0007",
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"\\b", "\\t", "\\n", "\\u000b",
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"\\f", "\\r", "\\u000e", "\\u000f",
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"\\u0010", "\\u0011", "\\u0012", "\\u0013",
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"\\u0014", "\\u0015", "\\u0016", "\\u0017",
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"\\u0018", "\\u0019", "\\u001a", "\\u001b",
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"\\u001c", "\\u001d", "\\u001e", "\\u001f",
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NULL, NULL, "\\\"", NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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"\\\\", NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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NULL, NULL, NULL, NULL,
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};
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static const byte JsonQuoteLengths[128] = {
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6, 6, 6, 6, 6, 6, 6, 6,
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2, 2, 2, 6, 2, 2, 6, 6,
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6, 6, 6, 6, 6, 6, 6, 6,
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6, 6, 6, 6, 6, 6, 6, 6,
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1, 1, 2, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 2, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1,
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};
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template <typename Char>
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Char* WriteString(Char* dst, const char* src_string) {
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char c;
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for (c = *src_string; c; c = *src_string) {
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*dst = c;
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dst++;
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src_string++;
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}
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return dst;
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}
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template <typename StringType>
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MaybeObject* AllocateRawString(int length);
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template <>
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MaybeObject* AllocateRawString<SeqTwoByteString>(int length) {
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return Heap::AllocateRawTwoByteString(length);
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}
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template <>
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MaybeObject* AllocateRawString<SeqAsciiString>(int length) {
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return Heap::AllocateRawAsciiString(length);
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}
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template <typename Char, typename StringType>
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static MaybeObject* QuoteJsonString(String* original,
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Vector<const Char> characters) {
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int length = characters.length();
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int quoted_length = 0;
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for (int i = 0; i < length; i++) {
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unsigned int c = characters[i];
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if (sizeof(Char) > 1u) {
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quoted_length +=
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(c >= sizeof(JsonQuoteLengths)) ? 1 : JsonQuoteLengths[c];
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} else {
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quoted_length += JsonQuoteLengths[c];
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}
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}
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if (quoted_length == length) {
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return Heap::undefined_value();
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}
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Counters::quote_json_char_count.Increment(length);
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// Add space for quotes.
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quoted_length += 2;
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MaybeObject* new_alloc = AllocateRawString<StringType>(quoted_length);
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Object* new_object;
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if (!new_alloc->ToObject(&new_object)) {
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Counters::quote_json_char_recount.Increment(length);
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return new_alloc;
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}
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StringType* new_string = StringType::cast(new_object);
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STATIC_ASSERT(SeqTwoByteString::kHeaderSize == SeqAsciiString::kHeaderSize);
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Char* write_cursor = reinterpret_cast<Char*>(
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new_string->address() + SeqAsciiString::kHeaderSize);
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*(write_cursor++) = '"';
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const Char* read_cursor = characters.start();
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const Char* end = read_cursor + length;
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while (read_cursor < end) {
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Char c = *(read_cursor++);
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if (sizeof(Char) > 1u && static_cast<unsigned>(c) >= sizeof(JsonQuotes)) {
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*(write_cursor++) = c;
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} else {
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const char* replacement = JsonQuotes[static_cast<unsigned>(c)];
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if (!replacement) {
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*(write_cursor++) = c;
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} else {
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write_cursor = WriteString(write_cursor, replacement);
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}
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}
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}
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*(write_cursor++) = '"';
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ASSERT_EQ(SeqAsciiString::kHeaderSize + quoted_length * sizeof(Char),
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reinterpret_cast<Address>(write_cursor) - new_string->address());
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return new_string;
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}
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static MaybeObject* Runtime_QuoteJSONString(Arguments args) {
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NoHandleAllocation ha;
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CONVERT_CHECKED(String, str, args[0]);
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if (!str->IsFlat()) {
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MaybeObject* try_flatten = str->TryFlatten();
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Object* flat;
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if (!try_flatten->ToObject(&flat)) {
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return try_flatten;
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}
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str = String::cast(flat);
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ASSERT(str->IsFlat());
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}
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if (str->IsTwoByteRepresentation()) {
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return QuoteJsonString<uc16, SeqTwoByteString>(str, str->ToUC16Vector());
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} else {
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return QuoteJsonString<char, SeqAsciiString>(str, str->ToAsciiVector());
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}
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}
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static MaybeObject* Runtime_StringParseInt(Arguments args) {
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NoHandleAllocation ha;
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@ -100,6 +100,7 @@ namespace internal {
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F(CharFromCode, 1, 1) \
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F(URIEscape, 1, 1) \
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F(URIUnescape, 1, 1) \
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F(QuoteJSONString, 1, 1) \
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\
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F(NumberToString, 1, 1) \
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F(NumberToStringSkipCache, 1, 1) \
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@ -224,7 +224,9 @@ namespace internal {
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SC(math_sqrt, V8.MathSqrt) \
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SC(math_tan, V8.MathTan) \
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SC(transcendental_cache_hit, V8.TranscendentalCacheHit) \
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SC(transcendental_cache_miss, V8.TranscendentalCacheMiss)
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SC(transcendental_cache_miss, V8.TranscendentalCacheMiss) \
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SC(quote_json_char_count, V8.QuoteJsonCharacterCount) \
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SC(quote_json_char_recount, V8.QuoteJsonCharacterReCount) \
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// This file contains all the v8 counters that are in use.
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