Added arguments to NaCl scons to allow custom toolchain directories.

Added arguments to NaCl scons to allow custom toolchain directories.

One feature that has been missing is to have a separate toolchain
directory on your machine and be able to use it no matter where it
was, this adds that support in NaCl for scons.

BUG=
R=dschuff@chromium.org

Committed: https://src.chromium.org/viewvc/native_client?view=rev&revision=13123

[David Yen, 2014-04-21 20:12:43]

Derek, here are the changes we discussed a little earlier about being able to
specify custom toolchain directories during builds. I still need to look into
how to get this working for gyp though... Normally I would have Brad review this
but he is not here, could you take a look?

[Derek Schuff, 2014-04-21 20:29:08]

On 2014/04/21 20:12:43, David Yen wrote:
> Derek, here are the changes we discussed a little earlier about being able to
> specify custom toolchain directories during builds. I still need to look into
> how to get this working for gyp though... Normally I would have Brad review
this
> but he is not here, could you take a look?

how does this interact with [p]naclsdk_mode?

[David Yen, 2014-04-21 20:32:20]

On 2014/04/21 20:29:08, Derek Schuff wrote:
> On 2014/04/21 20:12:43, David Yen wrote:
> > Derek, here are the changes we discussed a little earlier about being able
to
> > specify custom toolchain directories during builds. I still need to look
into
> > how to get this working for gyp though... Normally I would have Brad review
> this
> > but he is not here, could you take a look?
> 
> how does this interact with [p]naclsdk_mode?

It looks like naclsdk mode is hardcoded to always run from
"/usr/local/nacl-sdk". Not sure if this should be changed or the implications of
being able to redirect it.

[Derek Schuff, 2014-04-21 20:36:31]

On 2014/04/21 20:32:20, David Yen wrote:
> On 2014/04/21 20:29:08, Derek Schuff wrote:
> > On 2014/04/21 20:12:43, David Yen wrote:
> > > Derek, here are the changes we discussed a little earlier about being able
> to
> > > specify custom toolchain directories during builds. I still need to look
> into
> > > how to get this working for gyp though... Normally I would have Brad
review
> > this
> > > but he is not here, could you take a look?
> > 
> > how does this interact with [p]naclsdk_mode?
> 
> It looks like naclsdk mode is hardcoded to always run from
> "/usr/local/nacl-sdk". Not sure if this should be changed or the implications
of
> being able to redirect it.

I mean naclsdk_mode is a way to override the directory where scons looks for
toolchains. I don't think /usr/local/nacl-sdk is ever used though. we use
pnaclsdk_mode e.g. in the pnacl fyi bots (see
buildbot/buildbot_pnacl_toolchain_tests.sh ). see its implementation in in
site_scons/site_tools/naclsdk.py. Would this replace it, or is the use case for
this something that it can't be used for?

[David Yen, 2014-04-21 20:42:29]

On 2014/04/21 20:36:31, Derek Schuff wrote:
> On 2014/04/21 20:32:20, David Yen wrote:
> > On 2014/04/21 20:29:08, Derek Schuff wrote:
> > > On 2014/04/21 20:12:43, David Yen wrote:
> > > > Derek, here are the changes we discussed a little earlier about being
able
> > to
> > > > specify custom toolchain directories during builds. I still need to look
> > into
> > > > how to get this working for gyp though... Normally I would have Brad
> review
> > > this
> > > > but he is not here, could you take a look?
> > > 
> > > how does this interact with [p]naclsdk_mode?
> > 
> > It looks like naclsdk mode is hardcoded to always run from
> > "/usr/local/nacl-sdk". Not sure if this should be changed or the
implications
> of
> > being able to redirect it.
> 
> I mean naclsdk_mode is a way to override the directory where scons looks for
> toolchains. I don't think /usr/local/nacl-sdk is ever used though. we use
> pnaclsdk_mode e.g. in the pnacl fyi bots (see
> buildbot/buildbot_pnacl_toolchain_tests.sh ). see its implementation in in
> site_scons/site_tools/naclsdk.py. Would this replace it, or is the use case
for
> this something that it can't be used for?

I see what you mean, that is useful for specifying a single simple toolchain for
your build to use, but you can't specify multiple toolchains which you sometimes
might need.

For example, gdb only builds using newlib so if you are using a custom glibc
toolchain you will never be able to build gdb. At the same time, you can specify
the newlib toolchain to be a custom one, and you can build with glibc and only
gdb will be built with your custom toolchain.

[Derek Schuff, 2014-04-21 20:44:25]

So basically it sounds like you want to replace naclsdk_mode. That's sounds
good; can we actually replace it, rather than adding another way to do the same
thing?

[David Yen, 2014-04-21 22:29:22]

Okay, I removed all the (p)naclsdk_mode options and replaced them with
corresponding arguments for the custom toolchain directory. I also did a search
on the chromium side to make sure nothing is using it (nothing should be since
SCons is only used on the NaCl side).

[Derek Schuff, 2014-04-23 23:48:29]

LGTM

[David Yen, 2014-05-01 22:26:05]

Committed patchset #6 manually as r13123 (presubmit successful).