Optimize string escape functions

When generating Chromium's build files, this reduces the number of cycles gn
uses across all threads from 41,325,733,995 to 38,453,104,830 (-7%) indicated by
callgrind.  Runtime is also reduced from 3.45s to 3.43s (-0.6%) measured with
100 samples.  GN is likely bound more by disk IO and exec_script()'s than CPU
cycles, so that would explain why runtime reduction is only 0.6%.  But 0.6% is
still better than 0%.

BUG=None
R=brettw

Change-Id: Ief145407a0bf3ef00b13ce2532df4ff028f05c89
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/4620
Reviewed-by: Brett Wilson <brettw@google.com>
Commit-Queue: Brett Wilson <brettw@google.com>
1 file changed
tree: 9ff71e9a56ad2bed08597fed27d3ce07a9cc0917
  1. .clang-format
  2. .editorconfig
  3. .gitignore
  4. .style.yapf
  5. AUTHORS
  6. LICENSE
  7. OWNERS
  8. README.md
  9. base/
  10. build/
  11. docs/
  12. infra/
  13. tools/
  14. util/
README.md

GN

GN is a meta-build system that generates build files for Ninja. There is documentation in docs/ and a presentation on it.

Getting started

You can download the latest version of GN binary for Linux, macOS and Windows.

Alternatively, you can build GN from source:

git clone https://gn.googlesource.com/gn
cd gn
python build/gen.py
ninja -C out
# To run tests:
out/gn_unittests

On Windows, it is expected that cl.exe, link.exe, and lib.exe can be found in PATH, so you'll want to run from a Visual Studio command prompt, or similar.

On Linux and Mac, the default compiler is clang++, a recent version is expected to be found in PATH. This can be overridden by setting CC, CXX, and AR.

Reporting bugs

If you find a bug, you can see if it is known or report it in the bug database.

Sending patches

GN uses Gerrit for code review. The short version of how to patch is:

Register at https://gn-review.googlesource.com.

... edit code ...
ninja -C out && out/gn_unittests

Then, to upload a change for review:

git commit
git cl upload --gerrit

When revising a change, use:

git commit --amend
git cl upload --gerrit

which will add the new changes to the existing code review, rather than creating a new one.

We ask that all contributors sign Google's Contributor License Agreement (either individual or corporate as appropriate, select ‘any other Google project’).

Community

You may ask questions and follow along w/ GN‘s development on Chromium’s gn-dev@ Google Group.