[waffle] [PATCH v2 2/4] waffle: add support for building Waffle using NaCl toolchain

Mon Dec 29 02:28:00 PST 2014

On 12/29/2014 09:28 AM, Tapani Pälli wrote:
>
> On 12/23/2014 02:06 AM, Chad Versace wrote:
>> On 12/17/2014 04:17 AM, Tapani Pälli wrote:
>>> Patch adds changes required to use NaCl compiler and libraries to
>>> build Waffle. Build can be configured to use specific version of
>>> the NaCl SDK, toolchain for the build needs to be selected with
>>> cmake variable CMAKE_TOOLCHAIN_FILE.
>>>
>>> Example command line to configure a build:
>>>
>>> cmake -Dwaffle_has_nacl=ON \
>>>        -Dnacl_sdk_path=/home/tpalli/nacl/nacl_sdk \
>>>        -Dnacl_version=pepper_39 \
>>>
>>> -DCMAKE_TOOLCHAIN_FILE=cmake/toolchain-nacl-linux-glibc-x86_64.cmake \
>>>        -DCMAKE_BUILD_TYPE=Release \
>>
>> I tried really hard to simplify the CMake cmdline, but I failed. I'm
>> convinced
>> that this is simple as it gets.
>>
>>> v2: cmake fixes, create toolchain files for nacl (Emil Velikov)
>>>
>>> Signed-off-by: Tapani Pälli <tapani.palli at intel.com>
>>> ---
>>>   Options.cmake                                 |  5 +++++
>>>   cmake/Modules/WaffleDefineCompilerFlags.cmake |  4 ++++
>>>   cmake/Modules/WaffleValidateOptions.cmake     | 31
>>> +++++++++++++++++++++++++--
>>>   cmake/toolchain-nacl-linux-glibc-x86_32.cmake | 29
>>> +++++++++++++++++++++++++
>>>   cmake/toolchain-nacl-linux-glibc-x86_64.cmake | 29
>>> +++++++++++++++++++++++++
>>>   examples/CMakeLists.txt                       |  4 ++++
>>>   src/utils/CMakeLists.txt                      |  4 ++++
>>>   src/waffle/CMakeLists.txt                     |  6 ++++++
>>>   8 files changed, 110 insertions(+), 2 deletions(-)
>>>   create mode 100644 cmake/toolchain-nacl-linux-glibc-x86_32.cmake
>>>   create mode 100644 cmake/toolchain-nacl-linux-glibc-x86_64.cmake
>>>
>>
>>
>>> diff --git a/cmake/toolchain-nacl-linux-glibc-x86_32.cmake
>>> b/cmake/toolchain-nacl-linux-glibc-x86_32.cmake
>>
>> If you rename this file toolchain-nacl.cmake, and make a few changes,
>> then I think the same
>> file can be used for every host OS (Linux, Mac, Windows) and target
>> architecture.
>
> OK, this sounds ideal. I'm not able to test all these though so not sure
> if everything would work.
>
>>> new file mode 100644
>>> index 0000000..3c13bb6
>>> --- /dev/null
>>> +++ b/cmake/toolchain-nacl-linux-glibc-x86_32.cmake
>>
>> Nothing about this file is specific to Linux. I think you can rename this
>> file to toolchain-nacl-glibc-x86_32.cmake and, with a small change, have
>> it work on Mac (and possibly Windows) too.
>>
>> Also, I think the architecture is more significant, and should
>> therefore precede,
>> the C library variant. That is,
>>
>>      toolchain-nacl-{NACL_ARCH}[-{NACL_C_LIBRARY}].cmake
>>
>> instead of
>>
>>      toolchain-nacl-{NACL_C_LIBRARY}-{NACL_ARCH}.cmake
>>
>>
>> Otherwise, for PNaCl you end up with the weird name
>>
>>      toolchain-nacl-newlibc-pnacl.cmake
>>
>> instead of the simple name
>>
>>      toolchain-nacl-pnacl.cmake
>>
>> (The first is weird because newlibc is the only option for PNaCl. PNaCl
>> doesn't support glibc).
>
> Yes, this makes sense. I will change the naming scheme.
>
>>> @@ -0,0 +1,29 @@
>>> +#
>>> +# NaCl toolchain file for 32bit x86 using glibc C library
>>> +#
>>> +
>>> +set(CMAKE_SYSTEM_NAME Linux)
>>
>> Why did you choose to set CMAKE_SYSTEM_NAME to "Linux"? I expected it
>> to be set to "NaCl"
>> or left at its default value. Also, does setting it to "Linux" risk
>> breaking NaCl builds
>> done on Mac?
>
> Leaving it to default (not setting it) produces 'Error running link
> command: No such file or directory'. I think it leaves many needed cmake
> variables undefined so it needs to be there. Using 'unknown' system such
> as 'nacl' produces lots of warnings to console that I should consult
> with cmake at www.cmake.org to add 'nacl' as one of the options, it works
> though (with little addition to WaffleDefineOS.cmake) so it can be used.
> I can make this change if such warnings are ok.

Notably this also means that waffle_on_linux would be false when 
building for nacl (on linux too since CMAKE_SYSTEM_NAME is changed), I 
have a fear it will create some strange build problems but I will anyway 
take a try and see what comes out.

>
>>> +set(nacl_target_arch "i686")
>>> +set(nacl_ports "glibc_x86_32")
>>
>> You can make this file generic for Linux, Mac, and Windows by replacing
>>
>>> +set(nacl_toolchain "linux_x86_glibc")
>>
>> with
>>
>>      if(CMAKE_HOST_SYSTEM_NAME STREQUAL "Linux)
>>          set(nacl_host_os "linux")
>>      else()
>>          message(FATAL_ERROR "TODO: NaCl support on
>> ${CMAKE_HOST_SYSTEM_NAME}")
>>      endif()
>>
>>      set(nacl_toolchain "${nacl_host_os}_x86_glibc")
>>
>>
>>> +# setup paths for nacl
>>> +set(nacl_root ${nacl_sdk_path}/${nacl_version})
>>> +set(nacl_toolpath ${nacl_root}/toolchain/${nacl_toolchain}/bin)
>>> +
>>> +# setup compilers from toolchain
>>> +set(CMAKE_C_COMPILER ${nacl_toolpath}/${nacl_target_arch}-nacl-gcc)
>>> +set(CMAKE_CXX_COMPILER ${nacl_toolpath}/${nacl_target_arch}-nacl-g++)
>>> +
>>> +set(CMAKE_FIND_ROOT_PATH ${nacl_root})
>>> +
>>> +# for FIND_PROGRAM|LIBRARY|INCLUDE use ${nacl_root} only
>>> +set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM ONLY)
>>> +set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
>>> +set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
>>
>> I think you should set CMAKE_FIND_ROOT_PATH_MODE_PROGRAM to NEVER and
>> update the comment. For precedent, see the Piglit ebuild [1] in
>> Chromium OS.
>> If in the future Waffle needs to use a program (such as Python or the
>> Go compiler
>> or simply sed) to modify or generate sources at build time, then that
>> program
>> needs to be compatible with the build host's architecture and should
>> be taken
>> from the build host's PATH, not from the NaCl SDK. If Waffle does need
>> to use
>> some specific tool found in ${nacl_root}, then that tool's path should be
>> set explicitly in a new variable (such as, nacl_whizbang_tool) rather
>> than
>> relying the search path defined by CMAKE_FIND_ROOT.
>
> OK, I thought it a bit scary to mix host tools when cross compilation
> environment is in use as the environment can choose to override whatever
> tools it wants and I'm not sure what the search preference is (first
> host, then cross env?). But I can change this, it should work fine with
> nacl SDK.
>
>> [1]
>> https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/master/media-libs/piglit/piglit-2014.07.23.ebuild
>>
>>
>>> +# setup nacl includes and required libraries
>>> +set(nacl_INCLUDE_DIRS ${nacl_INCLUDE_DIRS}
>>> ${nacl_sdk_path}/${nacl_version}/include)
>>> +set(nacl_LIBS
>>> ${nacl_sdk_path}/${nacl_version}/lib/${nacl_ports}/${CMAKE_BUILD_TYPE})
>>> +set(nacl_LDFLAGS -L${nacl_LIBS} -lppapi_cpp -lppapi -lpthread -ldl)
>>
>>
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