Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 9c5c2c9fc89f8d977ead596d3066df729561df9c
https://github.com/WebKit/WebKit/commit/9c5c2c9fc89f8d977ead596d3066df729561df9c
Author: Yusuke Suzuki <ysuz...@apple.com>
Date: 2023-07-13 (Thu, 13 Jul 2023)
Changed paths:
A JSTests/stress/rope-resolve-recursive-non-ascii.js
A JSTests/stress/rope-resolve-recursive.js
A JSTests/stress/three-rope-non-ascii.js
A JSTests/stress/three-rope.js
A JSTests/stress/two-rope-non-ascii.js
A JSTests/stress/two-rope.js
M Source/JavaScriptCore/runtime/JSString.cpp
M Source/JavaScriptCore/runtime/JSString.h
M Source/JavaScriptCore/runtime/JSStringInlines.h
Log Message:
-----------
[JSC] JSRopeString::resolveToBuffer should have fast path for two
rope+non-rope case
https://bugs.webkit.org/show_bug.cgi?id=259176
rdar://112178098
Reviewed by Michael Saboff.
JSRopeString can have three fibers. But we observed two fibers case, where only
one is a rope, very commonly.
This happens when you write code like this,
var string = '';
for (var i = 0; i < 1e6; ++i)
string += char
Then, the resulted string becomes two fibers rope, only left hand side gets
super deep.
We can handle this string, just recursively handle the left side (via
tail-call), but just spreading the right side.
This patch changes JSRopeString::resolveToBuffer to handle this kind of
patterns efficiently. We carefully crafted this
code so that the above pattern becomes repeated tail call to
JSRopeString::resolveToBuffer. We also have sp checker so that
this code works perfectly well even if the compiler is not supporting
tail-calls (at some level, we stop and use slow-but-works mode).
* Source/JavaScriptCore/runtime/JSString.cpp:
(JSC::JSRopeString::resolveRopeInternalNoSubstring const):
(JSC::JSRopeString::resolveRopeToAtomString const):
(JSC::JSRopeString::resolveRopeToExistingAtomString const):
(JSC::JSRopeString::resolveRopeWithFunction const):
* Source/JavaScriptCore/runtime/JSString.h:
* Source/JavaScriptCore/runtime/JSStringInlines.h:
(JSC::JSRopeString::resolveToBuffer):
(JSC::jsAtomString):
Canonical link: https://commits.webkit.org/266028@main
_______________________________________________
webkit-changes mailing list
webkit-changes@lists.webkit.org
https://lists.webkit.org/mailman/listinfo/webkit-changes
