tree b03ac2bc9433237324b910cfdec1bfc293767663
parent bcfb647135e19cd806fd60e9638d7b8171d53c57
author David 'Digit' Turner <digit@google.com> 1547052082 +0100
committer Commit Bot <commit-bot@chromium.org> 1547052722 +0000

More efficient Value implementation.

Using a union to store all possible inner data-types means less
work whenever creating / copying / moving / destroying values,
and small size for each instance.

This results in a slightly faster "gn gen" operation, using
slightly less memory, i.e. when used with a Chromium checkout:

  $ /usr/bin/time -f "%M %U" /tmp/aa/gn-origin gen out/Release
  Done. Made 21651 targets from 1614 files in 6339ms
  764468 25.30

  $ /usr/bin/time -f "%M %U" /tmp/aa/gn-better-value gen out/Release
  Done. Made 21651 targets from 1614 files in 6014ms
  738132 23.27

R=brettw@chromium.org,dpranke@chromium.org
BUG=NONE

Change-Id: I6804857b1e69653713f038903f9abbbcae6ec62c
Reviewed-on: https://gn-review.googlesource.com/c/3662
Reviewed-by: Brett Wilson <brettw@chromium.org>
Commit-Queue: Brett Wilson <brettw@chromium.org>