509826 - replace js_NewStringCopyN uses with js_NewDependentString in jstr

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Luke Wagner [:luke]]

Attachment: patch

In find_replen and match_glob.

This resulted in a 2-3% speedup in string-unpack-code.

The patch also does a tiny bit o' cleanup.

Comment 1

[Luke Wagner [:luke]]

And for this micro-benchmark, 27% faster:

var d = new Date();
var a;
for (var i = 0; i < 200000; ++i) {
    a = "aabbccddaabbccddaabbccdd".replace(/(a+)(b+)(c+)(d+)/g, function(){return "."});
}
print(new Date() - d);

Comment 2

[Luke Wagner [:luke]]

Attachment: overly strong assertion, forgot about empty matches

Comment 3

[Robert Sayre]

review ping

Comment 4

[Jeff Walden [:Waldo]]

Comment on attachment 394175 [details] [diff] [review]
overly strong assertion, forgot about empty matches

>diff --git a/js/src/jsstr.cpp b/js/src/jsstr.cpp

>+        for (uintN j = 0; i < n; i++, j++) {
>+            if (!PushRegExpSubstr(cx, cx->regExpStatics.parens[j], sp))
>+                goto lambda_out;
>+        }
>+        for (uintN j = 0; i < m; i++, j++) {
>+            if (!PushRegExpSubstr(cx, cx->regExpStatics.moreParens[j], sp))
>+                goto lambda_out;
>+        }

I will assume we have dropped any compilers which hate "redeclaring" uintN j.  Ware tinderbox bustage.

Comment 5

[Luke Wagner [:luke]]

Thanks Waldo!

http://hg.mozilla.org/tracemonkey/rev/c857e77e6f01

Comment 6

[Robert Sayre]

http://hg.mozilla.org/mozilla-central/rev/c857e77e6f01

Comment 7

[Robert Sayre]

http://hg.mozilla.org/releases/mozilla-1.9.2/rev/937472db5fb9