This reverts commit e42e7fc800.
Reason for revert: Speculative revert for:
https://crbug.com/v8/7149
Original change's description:
> [objects] No longer create short external strings.
>
> This fixes String::MakeExternal() to bail out if the subject string
> doesn't fit a regular ExternalString, instead of creating a short
> external string. The observation here is that for short external strings
> the overhead of having to have the StringResource plus going to the
> runtime/C++ for each and every character access from JavaScript land
> is probably bigger than the anticipated benefits.
>
> If this turns out to be wrong and there's a real benefit, we should make
> use of ThinStrings instead of having a separate way to represent
> external strings.
>
> Bug: v8:6621, v8:7109, v8:7145
> Change-Id: I4b75da08b82a72027c782a69de9c8eaf3cca1d4d
> Reviewed-on: https://chromium-review.googlesource.com/799750
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#49735}
TBR=yangguo@chromium.org,bmeurer@chromium.org
Change-Id: I3f5cfa9ab5c99ddce1d61ede9ed9515cb3936cdd
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:6621, v8:7109, v8:7145, v8:7149
Reviewed-on: https://chromium-review.googlesource.com/801675
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49770}
This fixes String::MakeExternal() to bail out if the subject string
doesn't fit a regular ExternalString, instead of creating a short
external string. The observation here is that for short external strings
the overhead of having to have the StringResource plus going to the
runtime/C++ for each and every character access from JavaScript land
is probably bigger than the anticipated benefits.
If this turns out to be wrong and there's a real benefit, we should make
use of ThinStrings instead of having a separate way to represent
external strings.
Bug: v8:6621, v8:7109, v8:7145
Change-Id: I4b75da08b82a72027c782a69de9c8eaf3cca1d4d
Reviewed-on: https://chromium-review.googlesource.com/799750
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49735}
If a two-byte string only contains ascii characters, then we can save
memory when flattening a cons string containing it. Similarly we can
use this in Array.prototype.join implementation. To track this a new
bit is added to instance type. This bit is used as a hint in generated
code and in runtime functions.
To enable testing a new V8 extension is added controlled by
--expose-externalize-string flag.
Review URL: http://codereview.chromium.org/2762008
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4894 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
