Merge lp:~raof/mir/link-platforms-against-mirplatform into lp:mir

[Chris Halse Rogers]

Link the graphics platform libs with with libmirplatform.

They use symbols from it, so...

Another trivial one; link the platform plugins against libmirplatform, as they use its symbols.

[Daniel van Vugt (vanvugt)]

Verified the new linkage is honoured and used (not empty):

 libmirplatform.so.2 => ... /libmirplatform.so.2 (0x00007f20f5b2e000)
 libmircommon.so.2 => ... /libmircommon.so.2 (0x00007f20f4d88000)

Kind of scares me though that our linker options are so weak that we successfully built libmirplatformgraphics* at all before now.

review: Approve

[Daniel van Vugt (vanvugt)]

Something else scares me actually. Although the reality hasn't changed, it's now more clear that any ABI bump to libmircommon or libmirplatform will break 3rd party graphics drivers.

So if we can't eliminate these dependencies with a cleaner driver model then we will need to get serious about avoiding ABI breaks to mircommon/mirplatform.

[PS Jenkins bot (ps-jenkins)]

FAILED: Continuous integration, rev:1900
http://jenkins.qa.ubuntu.com/job/mir-team-mir-development-branch-ci/2660/
Executed test runs:
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-android-utopic-i386-build/1671
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-clang-utopic-amd64-build/1677
    FAILURE: http://jenkins.qa.ubuntu.com/job/mir-mediumtests-utopic-touch/1652/console
    FAILURE: http://jenkins.qa.ubuntu.com/job/mir-team-mir-development-branch-utopic-amd64-ci/1182/console
    FAILURE: http://jenkins.qa.ubuntu.com/job/mir-mediumtests-builder-utopic-armhf/589/console

Click here to trigger a rebuild:
http://s-jenkins.ubuntu-ci:8080/job/mir-team-mir-development-branch-ci/2660/rebuild

review: Needs Fixing (continuous-integration)

[Kevin DuBois (kdub)]

> Something else scares me actually. Although the reality hasn't changed, it's
> now more clear that any ABI bump to libmircommon or libmirplatform will break
> 3rd party graphics drivers.
>

The android platform depends-on the android drivers (so we can't break the android drivers with our abi/api changes).
The mesa platform provides its native window type and some function hooks that are needed to the mesa drivers, so the drivers depend-on the platform, and abi changes could break the drivers.

I guess the long term solution is to pull parts of the mesa drivers into the mesa platform, and have mesa depend-on headers provided by the drivers.

[Kevin DuBois (kdub)]

review: Approve

[Chris Halse Rogers (raof)]

There are two types of dependencies here - there are the classes that a driver has to provide, the definitions of which live in the platform module. If we change these, we've changed the driver ABI.

The other type is that *our* driver modules use functionality from mirplatform et al. That's perfectly fine; it's even OK if the driver module uses libmirplatformX-1 and gets loaded into a server using libmirplatformX (assuming we do the symbol versioning correctly).

Our driver ABI - while fragile, as C++ is not particularly conducive to backwards-compatible ABIs - shouldn't need to be broken _too_ often. Certainly it's not broken with each mirplatform ABI break (assuming we do the ELF versioning correctly ☺).

[Chris Halse Rogers (raof)]

Although that stupid protobuf singleton strikes again! Grargh.

[Chris Halse Rogers (raof)]

You know, depending on a library with a constructor is really annoying and awkward. I'll move this to WIP until (a) I can reproduce that failure locally, and (b) have some idea about what to do about it.

Unmerged revisions

1900. By Chris Halse Rogers on 2014-09-09

Link the graphics platform libs with with libmirplatform.

They use symbols from it, so...

=== modified file 'src/platform/graphics/android/CMakeLists.txt'
--- src/platform/graphics/android/CMakeLists.txt	2014-09-08 04:12:17 +0000
+++ src/platform/graphics/android/CMakeLists.txt	2014-09-09 06:26:38 +0000
@@ -51,6 +51,7 @@
   mirplatformgraphicsandroid
 
   mirsharedandroid
+  mirplatform
 
   ${Boost_PROGRAM_OPTIONS_LIBRARY}
   ${LIBHARDWARE_LIBRARIES}

=== modified file 'src/platform/graphics/mesa/CMakeLists.txt'
--- src/platform/graphics/mesa/CMakeLists.txt	2014-09-08 04:12:17 +0000
+++ src/platform/graphics/mesa/CMakeLists.txt	2014-09-09 06:26:38 +0000
@@ -48,6 +48,7 @@
 
 target_link_libraries(mirplatformgraphicsmesa
 
+  mirplatform
   ${Boost_PROGRAM_OPTIONS_LIBRARY}
   ${DRM_LDFLAGS} ${DRM_LIBRARIES}
   ${GBM_LDFLAGS} ${GBM_LIBRARIES}