tree f1e1cfbbc2a3f121e6163c8d70a4f81a0b1d1087
parent f0b4405f4e0809bcc4bb90644eccae4c806b7cd6
author Julie Hockett <juliehockett@google.com> 1530577908 -0700
committer Commit Bot <commit-bot@chromium.org> 1531257872 +0000

[gn] Add --export-compile-commands switch to gen

Adding a command line switch to generate a compilation database
(compile_commands.json) in the out/ directory. Compilation databases
are used by clang-based tools (e.g. clang-tidy, clangd, clang-rename).
CMake already does this with the -DEXPORT_COMPILE_COMMANDS option,
which regenerates the compdb whenever the ninja files are regenerated.

Use:
gn gen out/<builddir> --export-compile-commands

Setting this switch adds ~900ms to the `gn gen` command when run
on Chromium (wihtout --export-compile-commands == 2.7sec,
with --export-compile-commands == 3.6sec).

Change-Id: Ia3738e340b9de60da62557fb431a68a0618957fb
Reviewed-on: https://gn-review.googlesource.com/2040
Commit-Queue: Brett Wilson <brettw@chromium.org>
Reviewed-by: Brett Wilson <brettw@chromium.org>