Add experimental support for compiling with clang and ASan on Linux.

(Reland) Switch builds to clang by default for Linux and OS X.

Also adds support for ASan and sanitizer coverage.

BUG=pdfium:1, pdfium:171
R=thakis@chromium.org, thestig@chromium.org

Committed: https://pdfium.googlesource.com/pdfium/+/5478df43a8970257e9644ae6f57a6fe7513029c6

Committed: https://pdfium.googlesource.com/pdfium/+/3b2ab45f0a883046a7c457e8435b5a9b2c1c4156

[Oliver Chang, 2015-10-14 23:33:30]

PTAL. This CL right now uses $(which clang), but this causes issues with older
versions of clang (e.g. with clang-3.4, causes OOM death tests to fail for an
unknown reason I didn't dive into). 

I wonder if it makes sense to pull the clang toolchain used by chrome in DEPS. I
believe chrome gets them from
http://commondatastorage.googleapis.com/chromium-browser-clang/index.html using
a chromium specific update script.

[Lei Zhang, 2015-10-14 23:49:17]

thestig@chromium.org changed reviewers:
+ thakis@chromium.org

[Lei Zhang, 2015-10-14 23:49:18]

+thakis for all things Clang.

[Nico, 2015-10-14 23:55:21]

https://codereview.chromium.org/1406843002/diff/20001/build/standalone.gypi
File build/standalone.gypi (right):

https://codereview.chromium.org/1406843002/diff/20001/build/standalone.gypi#n...
build/standalone.gypi:269: ['CC', '<!(which clang)'],
Isn't it better if you deps in chromium's tools/clang/scripts and run update.sh
from a hooks and use that? (that's also what v8 does)

[Oliver Chang, 2015-10-15 01:00:49]

Thanks for the suggestion! Made the change and threw in sanitizer_coverage as
well.

https://codereview.chromium.org/1406843002/diff/20001/build/standalone.gypi
File build/standalone.gypi (right):

https://codereview.chromium.org/1406843002/diff/20001/build/standalone.gypi#n...
build/standalone.gypi:269: ['CC', '<!(which clang)'],
On 2015/10/14 23:55:21, Nico wrote:
> Isn't it better if you deps in chromium's tools/clang/scripts and run
update.sh
> from a hooks and use that? (that's also what v8 does)

Ah I didn't know v8 does this, thanks! I got a little put off by the seamingly
chromium specific stuff in the script but it seems like it works nicely here as
well.

[Oliver Chang, 2015-10-15 23:37:15]

Friendly ping, could you please take another look when you have time, Nico?

[Nico, 2015-10-15 23:41:22]

sorry, this fell off my inbox, thanks for the ping. the only real question below
is for base_dir

https://codereview.chromium.org/1406843002/diff/60001/DEPS
File DEPS (right):

https://codereview.chromium.org/1406843002/diff/60001/DEPS#newcode86
DEPS:86: # Note: On Win, this should run after win_toolchain, as it may use it.
There's no win_toolchain step here, so you probably want to remove this comment
(and check that runhooks continues to work on windows)

https://codereview.chromium.org/1406843002/diff/60001/build/standalone.gypi
File build/standalone.gypi (right):

https://codereview.chromium.org/1406843002/diff/60001/build/standalone.gypi#n...
build/standalone.gypi:41: 'base_dir%': '<!(cd <(DEPTH) && python -c "import os;
print os.getcwd()")',
I don't think you need this…build/common.gypi doesn't have it.

https://codereview.chromium.org/1406843002/diff/60001/build/standalone.gypi#n...
build/standalone.gypi:43: 'clang_dir%':
'<(base_dir)/third_party/llvm-build/Release+Asserts',
try removing the <(base_dir)/ prefix here

https://codereview.chromium.org/1406843002/diff/60001/build/standalone.gypi#n...
build/standalone.gypi:273: ['OS=="linux"', {
don't you want this on mac too?

actually, shouldn't clang default to 1 on mac and linux (since it does in
chromium)? (question for thestig, i suppose)

[Lei Zhang, 2015-10-16 00:23:16]

https://codereview.chromium.org/1406843002/diff/60001/build/standalone.gypi
File build/standalone.gypi (right):

https://codereview.chromium.org/1406843002/diff/60001/build/standalone.gypi#n...
build/standalone.gypi:273: ['OS=="linux"', {
On 2015/10/15 23:41:22, Nico wrote:
> don't you want this on mac too?
> 
> actually, shouldn't clang default to 1 on mac and linux (since it does in
> chromium)? (question for thestig, i suppose)

I don't build on Mac much, but I suppose we should use (our) Clang on Mac too.

[Oliver Chang, 2015-10-16 00:52:15]

thanks, Nico. I've addressed the comments.

https://codereview.chromium.org/1406843002/diff/60001/DEPS
File DEPS (right):

https://codereview.chromium.org/1406843002/diff/60001/DEPS#newcode86
DEPS:86: # Note: On Win, this should run after win_toolchain, as it may use it.
On 2015/10/15 23:41:22, Nico wrote:
> There's no win_toolchain step here, so you probably want to remove this
comment
> (and check that runhooks continues to work on windows)

Done.

https://codereview.chromium.org/1406843002/diff/60001/build/standalone.gypi
File build/standalone.gypi (right):

https://codereview.chromium.org/1406843002/diff/60001/build/standalone.gypi#n...
build/standalone.gypi:41: 'base_dir%': '<!(cd <(DEPTH) && python -c "import os;
print os.getcwd()")',
On 2015/10/15 23:41:22, Nico wrote:
> I don't think you need this…build/common.gypi doesn't have it.

Ah, I based this off v8's standalone.gypi, but I guess that's not needed here.

https://codereview.chromium.org/1406843002/diff/60001/build/standalone.gypi#n...
build/standalone.gypi:43: 'clang_dir%':
'<(base_dir)/third_party/llvm-build/Release+Asserts',
On 2015/10/15 23:41:22, Nico wrote:
> try removing the <(base_dir)/ prefix here

Done.

https://codereview.chromium.org/1406843002/diff/60001/build/standalone.gypi#n...
build/standalone.gypi:273: ['OS=="linux"', {
On 2015/10/16 00:23:16, Lei Zhang wrote:
> On 2015/10/15 23:41:22, Nico wrote:
> > don't you want this on mac too?
> > 
> > actually, shouldn't clang default to 1 on mac and linux (since it does in
> > chromium)? (question for thestig, i suppose)
> 
> I don't build on Mac much, but I suppose we should use (our) Clang on Mac too.

I don't have a Mac to test this on, but I guess it doesn't hurt to include Mac
in this.

I've gone ahead and set clang to 1 by default for mac and linux. Will setting
this break anything infrastructure-wise, Lei?

[Lei Zhang, 2015-10-16 00:53:34]

On 2015/10/16 00:52:15, Oliver Chang wrote:
> I don't have a Mac to test this on, but I guess it doesn't hurt to include Mac
> in this.

Let me try this on Mac...

> I've gone ahead and set clang to 1 by default for mac and linux. Will setting
> this break anything infrastructure-wise, Lei?

Should be ok. Commit and find out?

[Lei Zhang, 2015-10-16 00:58:36]

Oh, should we add third_party/llvm-build/ and tools/clang to .gitignore?

[Oliver Chang, 2015-10-16 01:01:48]

done

[Lei Zhang, 2015-10-16 01:14:43]

On 2015/10/16 00:53:34, Lei Zhang wrote:
> On 2015/10/16 00:52:15, Oliver Chang wrote:
> > I don't have a Mac to test this on, but I guess it doesn't hurt to include
Mac
> > in this.
> 
> Let me try this on Mac...

No issues there.

[Oliver Chang, 2015-10-19 16:23:41]

friendly ping again, Nico :)

[Nico, 2015-10-19 16:28:19]

lgtm

https://codereview.chromium.org/1406843002/diff/100001/.gitignore
File .gitignore (right):

https://codereview.chromium.org/1406843002/diff/100001/.gitignore#newcode9
.gitignore:9: /third_party/llvm
this shouldn't get checked out, if it does something went wrong (your call if
you want to keep this line, it doesn't hurt either)

[Oliver Chang, 2015-10-19 18:17:00]

Description was changed from

==========
Switch builds to clang by default for Linux and OS X.

Also adds support for ASan and sanitizer coverage.

R=thestig@chromium.org,thakis@chromium.org
==========

to

==========
Switch builds to clang by default for Linux and OS X.

Also adds support for ASan and sanitizer coverage.

BUG=pdfium:1

R=thestig@chromium.org,thakis@chromium.org
==========

[Oliver Chang, 2015-10-19 18:17:53]

Description was changed from

==========
Switch builds to clang by default for Linux and OS X.

Also adds support for ASan and sanitizer coverage.

BUG=pdfium:1

R=thestig@chromium.org,thakis@chromium.org
==========

to

==========
Switch builds to clang by default for Linux and OS X.

Also adds support for ASan and sanitizer coverage.

BUG=pdfium:1,pdfium:171

R=thestig@chromium.org,thakis@chromium.org
==========

[Oliver Chang, 2015-10-19 18:19:26]

Committed patchset #7 (id:120001) manually as
5478df43a8970257e9644ae6f57a6fe7513029c6 (presubmit successful).

[Lei Zhang, 2015-10-19 18:44:50]

On 2015/10/19 16:28:19, Nico wrote:
> lgtm
> 
> https://codereview.chromium.org/1406843002/diff/100001/.gitignore
> File .gitignore (right):
> 
> https://codereview.chromium.org/1406843002/diff/100001/.gitignore#newcode9
> .gitignore:9: /third_party/llvm
> this shouldn't get checked out, if it does something went wrong (your call if
> you want to keep this line, it doesn't hurt either)

It's just an empty directory here.

[Oliver Chang, 2015-10-19 19:36:22]

this didn't seem to work on the buildbots because the hooks didn't seem to get
run (and clang wasn't pulled). will take a look later...

[Nico, 2015-10-19 19:41:26]

do you have a bot link?

[Oliver Chang, 2015-10-19 19:43:51]

linux: http://build.chromium.org/p/client.pdfium/builders/linux/builds/642

win (looks like a separate issue):
http://build.chromium.org/p/client.pdfium/builders/win/builds/475

[Oliver Chang, 2015-10-21 19:53:16]

Description was changed from

==========
Switch builds to clang by default for Linux and OS X.

Also adds support for ASan and sanitizer coverage.

BUG=pdfium:1,pdfium:171
R=thakis@chromium.org, thestig@chromium.org

Committed:
https://pdfium.googlesource.com/pdfium/+/5478df43a8970257e9644ae6f57a6fe75130...
==========

to

==========
(Reland) Switch builds to clang by default for Linux and OS X.

Also adds support for ASan and sanitizer coverage.

BUG=pdfium:1,pdfium:171
R=thakis@chromium.org, thestig@chromium.org

Committed:
https://pdfium.googlesource.com/pdfium/+/5478df43a8970257e9644ae6f57a6fe75130...
==========

[Oliver Chang, 2015-10-21 20:19:33]

Committed patchset #8 (id:140001) manually as
3b2ab45f0a883046a7c457e8435b5a9b2c1c4156 (presubmit successful).