Things seem to be even worse now, the compiler is crashing when trying to build that target :(

Checking out with the previous clang roll.

The same crash when building with the previous clang revision ( issue 863425 ). Fun!

chrome@ git-hash c47e277ca2dbf13b4bb5e402a7330c29805c04ac

% gn args out/coverage
Waiting for editor on "$HOME/chrome/src/out/coverage/args.gn"...
Generating files...
Done. Made 11307 targets from 1892 files in 3595ms

% gn args out/coverage --list --short --overrides-only
crashpad_dependencies = "chromium"
is_component_build = false
is_debug = false
rtc_include_ilbc = false
rtc_link_task_queue_impl = false
target_os = "chromeos"
use_clang_coverage = true
use_goma = true
v8_check_microtasks_scopes_consistency = false
v8_enable_gdbjit = false
v8_experimental_extra_library_files = []
v8_extra_library_files = ["<file-list-elided>..."]
v8_imminent_deprecation_warnings = false

% python tools/code_coverage/coverage.py browser_tests \
    -b  out/coverage -o out/report \
    -c 'out/coverage/browser_tests --gtest_filter=*FilesAppBrowserTest*' \
    -f  chrome/browser/chromeos/file_manager

Downloading https://commondatastorage.googleapis.com/chromium-browser-clang/Linux_x64/llvm-code-coverage-336424-1.tgz .......... Done.

[2018-07-20 10:40:05,824 INFO] Building ['browser_tests'].
ninja: Entering directory `$HOME/chrome/src/out/coverage' 

Crashes for me too. Crash log attached.

Deleted: chrome-os-coverage-crash.txt 14.6 KB

chrome-os-coverage-crash.txt 14.6 KB View Download

Tried the 'unit_tests' target for the record.

  python tools/code_coverage/coverage.py unit_tests \
    -b  out/coverage -o out/report \
    -c 'out/coverage/unit_tests' \
    -f  chrome/browser/chromeos/file_manager

No crash there.

Deleted: chrome_browser_chromeos_file_manager_unittest_report.png 640 KB

	chrome_browser_chromeos_file_manager_unittest_report.png 640 KB View Download

The original issue though is not related to the coverage script. Coverage script downloads only llvm-cov and llvm-profdata utilities, while compiler-rt*profile* library should be downloaded amongst other LLVM libraries.


I know how it works for Linux, Mac and Windows: https://cs.chromium.org/chromium/src/tools/clang/scripts/package.py?q=package.py&sq=package:chromium&g=0&l=272

But can't see how LLVM package for Android is getting created, so CC'ing some other folks who can advice on this.

Still unclear why target_os="chromeos" built on Linux needs Android library, but likely it's WAI since non-coverage builds work fine.

Android stuff is generally in the linux package:

s$ ls ~/Downloads/clang-337439-1/lib/clang/7.0.0/lib/linux/*android*
/Users/thakis/Downloads/clang-337439-1/lib/clang/7.0.0/lib/linux/libclang_rt.asan-aarch64-android.so			/Users/thakis/Downloads/clang-337439-1/lib/clang/7.0.0/lib/linux/libclang_rt.ubsan_standalone-aarch64-android.so
/Users/thakis/Downloads/clang-337439-1/lib/clang/7.0.0/lib/linux/libclang_rt.asan-arm-android.so			/Users/thakis/Downloads/clang-337439-1/lib/clang/7.0.0/lib/linux/libclang_rt.ubsan_standalone-arm-android.so
/Users/thakis/Downloads/clang-337439-1/lib/clang/7.0.0/lib/linux/libclang_rt.asan-i686-android.so			/Users/thakis/Downloads/clang-337439-1/lib/clang/7.0.0/lib/linux/libclang_rt.ubsan_standalone-i686-android.so


But we don't bundle libprofile for android since it's not needed for regular android builds. If we were to bundle it, we probably wouldn't bundle it for x86-64 since most android devices are arm.

ChromeOS devices are x86-64 or arm.

Sure, but "coverage for the android part of a chromeos build" is a somewhat exotic flag combination. Maybe we could make it so that coverage flags aren't passed in to the android part of a cros build.

Agree, semi-exotic.  Not having clang coverage flags passed into the android part of a cros build would work for me.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d89549b20cedcf250e16cf5d98a89ed0b691e6e0

commit d89549b20cedcf250e16cf5d98a89ed0b691e6e0
Author: Max Moroz <mmoroz@chromium.org>
Date: Tue Jul 31 16:19:55 2018

Build and bundle compiler-rt profile library for Android.

This is needed for supporting profiling and code coverage reporting on
ChromeOS and Android.

Bug: 843356,865376
Change-Id: I36836a7876c5e9230b33594362ac029bc1670c86
Reviewed-on: https://chromium-review.googlesource.com/1153653
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Abhishek Arya <inferno@chromium.org>
Reviewed-by: Hans Wennborg <hans@chromium.org>
Commit-Queue: Max Moroz <mmoroz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579426}
[modify] https://crrev.com/d89549b20cedcf250e16cf5d98a89ed0b691e6e0/tools/clang/scripts/update.py

Apparently we don't even build compiler-rt libraries for Android x86_64. 

I guess I'm WontFix'ing this. Noel, if you really need to run coverage in this configuration, I probably can build that missing library for you, but no promises that other pieces would work :(

For the solution discussed in c#8 and c#9 you just need to remove "//build/config/coverage:default_coverage" under certain conditions in GN file of your interest, e.g. https://cs.chromium.org/chromium/src/chrome/test/data/nacl/BUILD.gn?type=cs&q=%22:default_coverage%22&g=0&l=614

Once the compiler crash is fixed in Clang, will this bug still not be actionable? I am trying to get a sense of what all needs to be fixed for us to get Code Coverage working on Chrome on Chrome OS.

rkc@, which CPU architectures do you need?

Either ARM or x64 should work for us. The code we're trying to measure coverage on should not deviate too much on either of the architectures.

In ARM case, we should be in a better shape, I believe. Someone just has to try building some test target :) Better to start with something small.

This bug's x64 link failure is due to cross compilation of mojo bindings for Android, done as part of the Chrome OS on Linux build.

Then see #8 and #9 above, an idea that seems to work (diff attached), and with it, I was able to compile Chrome OS browser tests with clang coverage enabled.

Deleted: clang-coverage.git.diff 817 bytes

clang-coverage.git.diff 817 bytes Download

I'm re-opening this bug since there are still activities.

Re #12: sorry I missed your comment. This bug will be actionable once the platform specific issues are fixed.

That said, someone should fix the platform specific issues (compiler crash is a known one, there maybe more) so that the coverage.py script can successfully generate code coverage reports for the list of targets you're interested in, and then our team can take care of the rest at the infrastructure side to set up the CI builders and get the reports integrated into the dashboard.