commit 331266377d03b51dc3e2cf2c26b896e21f8f0391
author Alexandr Ilin <alexilin@chromium.org> Wed Nov 14 14:48:17 2018
committer Commit Bot <commit-bot@chromium.org> Wed Nov 14 14:48:17 2018
tree 9bbb5ddc4d05fb37e5811ecdd336689d1950d2cf
parent 65644ef9859380e742f3a5d91c627e3b3e942183

Constexpr-eliminate GetCategoryGroupEnabled calls for popular categories

This CL allows to avoid the cost of calling GetCategoryGroupEnabled() in
TRACE_EVENT macros for popular categories, in a way that doesn't require more
macros, nor changing all the call sites.

The idea is to put all popular categories into a static global array so an
address of a category state may be determined at compile-time through a call
to a constexpr function.

This CL makes it impossible to use non constant expressions as a category name
in the tracing macros. All the call sites that don't satisfy this requirement
have to be converted. Hopefully, there aren't a lot of such callers.

This change reduces the code size generated from each trace macro by ~16 bytes,
check the full report here:
https://docs.google.com/document/d/1piIq_yi2fsqOEKObx0tFHeunMyX7hp2ZdAGKK6t0k80/edit?usp=sharing.
The total Android apk size savings are ~60 KiB.

Bug: 702718, 708990
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I9f7b48fd4ee614996feaabda3e5495fd9b786c3a
Reviewed-on: https://chromium-review.googlesource.com/c/1251361
Commit-Queue: Alexandr Ilin <alexilin@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Primiano Tucci <primiano@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Reviewed-by: Frank Liberato <liberato@chromium.org>
Reviewed-by: vmpstr <vmpstr@chromium.org>
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Reviewed-by: David Turner <digit@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607975}