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Restructure RegExp exec cache code.

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Review URL: http://codereview.chromium.org/3778004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5622 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
lrn@chromium.org 2010-10-14 12:54:00 +00:00
parent e144c259c5
commit d5ac565882
3 changed files with 176 additions and 66 deletions
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150
src/regexp.js
View File

@ -126,11 +126,11 @@ function RegExpCache() {
this.regExp = 0;
this.subject = 0;
this.replaceString = 0;
this.lastIndex = 0; // Also used for splitLimit when type is "split"
this.answer = 0;
// answerSaved marks whether the contents of answer is valid for a cache
// hit in RegExpExec, StringMatch and StringSplit.
this.answerSaved = false;
this.splitLimit = 0; // Used only when type is "split".
}
@ -181,22 +181,30 @@ function RegExpExec(string) {
var cache = regExpCache;
var saveAnswer = false;
var lastIndex = this.lastIndex;
// Since cache.subject is always a string, a matching input can not
// cause visible side-effects when converted to a string, so we can omit
// the conversion required by the specification.
// Likewise, the regexp.lastIndex and regexp.global properties are value
// properties that are not configurable, so reading them can also not cause
// any side effects (converting lastIndex to a number can, though).
if (%_ObjectEquals(cache.type, 'exec') &&
%_ObjectEquals(cache.lastIndex, this.lastIndex) &&
%_ObjectEquals(0, lastIndex) &&
%_IsRegExpEquivalent(cache.regExp, this) &&
%_ObjectEquals(cache.subject, string)) {
if (cache.answerSaved) {
// If this regexp is global, cache.lastIndex is zero, so we only get
// here if this.lastIndex is zero, and resulting this.lastIndex
// must be zero too, so no change is necessary.
if (!this.global) this.lastIndex = lastMatchInfo[CAPTURE1];
// The regexp.lastIndex value must be 0 for non-global RegExps, and for
// global RegExps we only cache negative results, which gives a lastIndex
// of zero as well.
this.lastIndex = 0;
return %_RegExpCloneResult(cache.answer);
} else {
saveAnswer = true;
}
}
if (%_ArgumentsLength() == 0) {
if (%_ArgumentsLength() === 0) {
var regExpInput = LAST_INPUT(lastMatchInfo);
if (IS_UNDEFINED(regExpInput)) {
throw MakeError('no_input_to_regexp', [this]);
@ -209,41 +217,48 @@ function RegExpExec(string) {
} else {
s = ToString(string);
}
var lastIndex = this.lastIndex;
var global = this.global;
var i = this.global ? TO_INTEGER(lastIndex) : 0;
if (i < 0 || i > s.length) {
this.lastIndex = 0;
return null;
// Conversion is required by the ES5 specification (RegExp.prototype.exec
// algorithm, step 5) even if the value is discarded for non-global RegExps.
var i = TO_INTEGER(lastIndex);
if (global) {
if (i < 0 || i > s.length) {
this.lastIndex = 0;
return null;
}
} else {
i = 0;
}
%_Log('regexp', 'regexp-exec,%0r,%1S,%2i', [this, s, lastIndex]);
// matchIndices is either null or the lastMatchInfo array.
var matchIndices = %_RegExpExec(this, s, i, lastMatchInfo);
if (matchIndices == null) {
if (this.global) {
if (matchIndices === null) {
if (global) {
// Cache negative result only if initial lastIndex was zero.
this.lastIndex = 0;
if (lastIndex != 0) return matchIndices;
if (lastIndex !== 0) return matchIndices;
}
cache.lastIndex = lastIndex;
cache.regExp = this;
cache.subject = s;
cache.answer = matchIndices; // Null.
cache.subject = s; // Always a string.
cache.answer = null;
cache.answerSaved = true; // Safe since no cloning is needed.
cache.type = 'exec';
return matchIndices; // No match.
}
// Successful match.
lastMatchInfoOverride = null;
var result = BuildResultFromMatchInfo(matchIndices, s);
if (this.global) {
if (global) {
// Don't cache positive results for global regexps.
this.lastIndex = lastMatchInfo[CAPTURE1];
} else {
cache.regExp = this;
cache.subject = s;
cache.lastIndex = lastIndex;
if (saveAnswer) cache.answer = %_RegExpCloneResult(result);
cache.answerSaved = saveAnswer;
cache.type = 'exec';
@ -273,32 +288,49 @@ function RegExpTest(string) {
}
string = regExpInput;
}
var lastIndex = this.lastIndex;
var cache = regExpCache;
if (%_ObjectEquals(cache.type, 'test') &&
%_IsRegExpEquivalent(cache.regExp, this) &&
%_ObjectEquals(cache.subject, string) &&
%_ObjectEquals(0, lastIndex)) {
// The regexp.lastIndex value must be 0 for non-global RegExps, and for
// global RegExps we only cache negative results, which gives a resulting
// lastIndex of zero as well.
if (global) this.lastIndex = 0;
return cache.answer;
}
var s;
if (IS_STRING(string)) {
s = string;
} else {
s = ToString(string);
}
var length = s.length;
var lastIndex = this.lastIndex;
var cache = regExpCache;
if (%_ObjectEquals(cache.type, 'test') &&
%_IsRegExpEquivalent(cache.regExp, this) &&
%_ObjectEquals(cache.subject, string) &&
%_ObjectEquals(cache.lastIndex, lastIndex)) {
// If this regexp is not global, cache.lastIndex is zero, so we only get
// here if this.lastIndex is zero, and resulting this.lastIndex
// must be zero too, so no change is necessary.
if (this.global) this.lastIndex = lastMatchInfo[CAPTURE1];
return cache.answer;
// Conversion is required by the ES5 specification (RegExp.prototype.exec
// algorithm, step 5) even if the value is discarded for non-global RegExps.
var i = TO_INTEGER(lastIndex);
if (global) {
if (i < 0 || i > length) {
this.lastIndex = 0;
return false;
}
} else {
i = 0;
}
var global = this.global;
// Remove irrelevant preceeding '.*' in a test regexp. The expression
// checks whether this.source starts with '.*' and that the third
// char is not a '?'
if (%_StringCharCodeAt(this.source,0) == 46 && // '.'
%_StringCharCodeAt(this.source,1) == 42 && // '*'
%_StringCharCodeAt(this.source,2) != 63) { // '?'
if (%_StringCharCodeAt(this.source, 0) == 46 && // '.'
%_StringCharCodeAt(this.source, 1) == 42 && // '*'
%_StringCharCodeAt(this.source, 2) != 63) { // '?'
if (!%_ObjectEquals(regexp_key, this)) {
regexp_key = this;
regexp_val = new $RegExp(this.source.substring(2, this.source.length),
@ -309,33 +341,28 @@ function RegExpTest(string) {
if (!regexp_val.test(s)) return false;
}
var length = s.length;
var i = this.global ? TO_INTEGER(lastIndex) : 0;
cache.type = 'test';
cache.regExp = this;
cache.subject = s;
cache.lastIndex = i;
if (i < 0 || i > length) {
this.lastIndex = 0;
cache.answer = false;
return false;
}
%_Log('regexp', 'regexp-exec,%0r,%1S,%2i', [this, s, lastIndex]);
// matchIndices is either null or the lastMatchInfo array.
var matchIndices = %_RegExpExec(this, s, i, lastMatchInfo);
if (matchIndices == null) {
if (this.global) this.lastIndex = 0;
cache.answer = false;
return false;
var result = (matchIndices !== null);
if (result) {
lastMatchInfoOverride = null;
}
lastMatchInfoOverride = null;
if (this.global) this.lastIndex = lastMatchInfo[CAPTURE1];
cache.answer = true;
return true;
if (global) {
if (result) {
this.lastIndex = lastMatchInfo[CAPTURE1];
return true;
} else {
this.lastIndex = 0;
if (lastIndex !== 0) return false;
}
}
cache.type = 'test';
cache.regExp = this;
cache.subject = s;
cache.answer = result;
return result;
}
@ -345,12 +372,9 @@ function RegExpToString() {
// ecma_2/RegExp/properties-001.js.
var src = this.source ? this.source : '(?:)';
var result = '/' + src + '/';
if (this.global)
result += 'g';
if (this.ignoreCase)
result += 'i';
if (this.multiline)
result += 'm';
if (this.global) result += 'g';
if (this.ignoreCase) result += 'i';
if (this.multiline) result += 'm';
return result;
}

5
src/string.js
View File

@ -611,7 +611,7 @@ function StringSplit(separator, limit) {
if (%_ObjectEquals(cache.type, 'split') &&
%_IsRegExpEquivalent(cache.regExp, separator) &&
%_ObjectEquals(cache.subject, subject) &&
%_ObjectEquals(cache.lastIndex, limit)) {
%_ObjectEquals(cache.splitLimit, limit)) {
if (cache.answerSaved) {
return CloneDenseArray(cache.answer);
} else {
@ -622,8 +622,7 @@ function StringSplit(separator, limit) {
cache.type = 'split';
cache.regExp = separator;
cache.subject = subject;
// Reuse lastIndex field for split limit when type is "split".
cache.lastIndex = limit;
cache.splitLimit = limit;
%_Log('regexp', 'regexp-split,%0S,%1r', [subject, separator]);

87
test/mjsunit/regexp.js
View File

@ -502,3 +502,90 @@ for (var i = 0; i < 100; i++) {
res[3] = "Glopglyf";
assertEquals("Arglebargle", res.foobar);
}
// Test that we perform the spec required conversions in the correct order.
var log;
var string = "the string";
var fakeLastIndex = {
valueOf: function() {
log.push("li");
return 0;
}
};
var fakeString = {
toString: function() {
log.push("ts");
return string;
},
length: 0
};
var re = /str/;
log = [];
re.lastIndex = fakeLastIndex;
var result = re.exec(fakeString);
assertEquals(["str"], result);
assertEquals(["ts", "li"], log);
// Again, to check if caching interferes.
log = [];
re.lastIndex = fakeLastIndex;
result = re.exec(fakeString);
assertEquals(["str"], result);
assertEquals(["ts", "li"], log);
// And one more time, just to be certain.
log = [];
re.lastIndex = fakeLastIndex;
result = re.exec(fakeString);
assertEquals(["str"], result);
assertEquals(["ts", "li"], log);
// Now with a global regexp, where lastIndex is actually used.
re = /str/g;
log = [];
re.lastIndex = fakeLastIndex;
var result = re.exec(fakeString);
assertEquals(["str"], result);
assertEquals(["ts", "li"], log);
// Again, to check if caching interferes.
log = [];
re.lastIndex = fakeLastIndex;
result = re.exec(fakeString);
assertEquals(["str"], result);
assertEquals(["ts", "li"], log);
// And one more time, just to be certain.
log = [];
re.lastIndex = fakeLastIndex;
result = re.exec(fakeString);
assertEquals(["str"], result);
assertEquals(["ts", "li"], log);
// Check that properties of RegExp have the correct permissions.
var re = /x/g;
var desc = Object.getOwnPropertyDescriptor(re, "global");
assertEquals(true, desc.value);
assertEquals(false, desc.configurable);
assertEquals(false, desc.enumerable);
assertEquals(false, desc.writable);
desc = Object.getOwnPropertyDescriptor(re, "multiline");
assertEquals(false, desc.value);
assertEquals(false, desc.configurable);
assertEquals(false, desc.enumerable);
assertEquals(false, desc.writable);
desc = Object.getOwnPropertyDescriptor(re, "ignoreCase");
assertEquals(false, desc.value);
assertEquals(false, desc.configurable);
assertEquals(false, desc.enumerable);
assertEquals(false, desc.writable);
desc = Object.getOwnPropertyDescriptor(re, "lastIndex");
assertEquals(0, desc.value);
assertEquals(false, desc.configurable);
assertEquals(false, desc.enumerable);
assertEquals(true, desc.writable);