Get per-file compile times

• Component: Tools / Tests
• Status: NEW ---

[Nico Weber]

Several approaches:
* ninja outputs these automatically into ninja.log
* Or one can set CC to a wrapper script that does `time gcc $*` and then writes the time somewhere (e.g. just >> to some log file, that's probably easiest)

(https://github.com/nico/complete/blob/master/server/builddb-cc is an overdesigned cc replacement that also injects a clang plugin and writes to a sqlite db. Mostly useful for entertainment purposes, but it also shows how to set CC so that xcodebuild sees it)

[Eric Seidel (no email)]

timing-cc:

#!/bin/bash
echo $* >> /tmp/time.txt
(time gcc "$@") 2>> /tmp/time.txt

CC=/path/to/timing-cc build-webkit

seems to work.  Seems to spit out a bunch of junk at the top of the file, but I think that's just normal gcc stderr output which is normally not displayed by xcodebuild.

[Eric Seidel (no email)]

Follow-up from Sam's session.

[Evan Martin]

You probably will want to lock the output file to prevent parallel gcc processes from interleaving.  Otherwise Eric's script LGTM.