[llvm] r313770 - [cmake] Add an option to build llvm with IR PGO

[Justin Bogner via llvm-commits]

Vedant Kumar <vsk at apple.com> writes:
>> On Nov 7, 2017, at 5:22 PM, Justin Bogner <mail at justinbogner.com> wrote:
>> 
>> Vedant Kumar via llvm-commits <llvm-commits at lists.llvm.org> writes:
>>> Author: vedantk
>>> Date: Wed Sep 20 10:16:01 2017
>>> New Revision: 313770
>>> 
>>> URL: http://llvm.org/viewvc/llvm-project?rev=313770&view=rev
>>> Log:
>>> [cmake] Add an option to build llvm with IR PGO
>>> 
>>> This adds an LLVM_ENABLE_IR_PGO option to enable building llvm and its
>>> tools with IR PGO instrumentation.
>>> 
>>> Usage: -DLLVM_BUILD_INSTRUMENTED=On -DLLVM_ENABLE_IR_PGO=On (both
>>> options must be enabled)
>> 
>> Why not make LLVM_BUILD_INSTRUMENTED a string like "FE" or "IR" instead
>> of a bool?
>
> I didn't want to break setups which set LLVM_BUILD_INSTRUMENTED:BOOL.

See how LLVM_ENABLE_LTO handled that - it treats bools in that spot as
the old way and then handles the explicit options the new way. If you
think that overloads the flag too much that's fine though.

>> There's some prior art for that approach with how the
>> LLVM_ENABLE_LTO flag works. Having to specify two parameters for this
>> (and the fact that LLVM_ENABLE_IR_PGO is meaningless without the other)
>> is awkward.
>
> It makes sense to make LLVM_ENABLE_IR_PGO meaningful by itself. We
> just need to update the PGO cmake cache accordingly.
>
> vedant
>
>> 
>>> Differential Revision: https://reviews.llvm.org/D38066
>>> 
>>> Modified:
>>>    llvm/trunk/CMakeLists.txt
>>>    llvm/trunk/cmake/modules/HandleLLVMOptions.cmake
>>> 
>>> Modified: llvm/trunk/CMakeLists.txt
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/CMakeLists.txt?rev=313770&r1=313769&r2=313770&view=diff
>>> ==============================================================================
>>> 
>>> --- llvm/trunk/CMakeLists.txt (original)
>>> +++ llvm/trunk/CMakeLists.txt Wed Sep 20 10:16:01 2017
>>> @@ -548,7 +548,8 @@ else()
>>>   set(LLVM_ADD_NATIVE_VISUALIZERS_TO_SOLUTION FALSE CACHE INTERNAL "For Visual Studio 2013, manually copy natvis files to Documents\\Visual Studio 2013\\Visualizers" FORCE)
>>> endif()
>>> 
>>> -if (LLVM_BUILD_INSTRUMENTED OR LLVM_BUILD_INSTRUMENTED_COVERAGE)
>>> +if (LLVM_BUILD_INSTRUMENTED OR LLVM_BUILD_INSTRUMENTED_COVERAGE OR
>>> +    LLVM_ENABLE_IR_PGO)
>>>   if(NOT LLVM_PROFILE_MERGE_POOL_SIZE)
>>>     # A pool size of 1-2 is probably sufficient on a SSD. 3-4 should be fine
>>>     # for spining disks. Anything higher may only help on slower mediums.
>>> @@ -556,10 +557,9 @@ if (LLVM_BUILD_INSTRUMENTED OR LLVM_BUIL
>>>   endif()
>>>   if(NOT LLVM_PROFILE_FILE_PATTERN)
>>>     if(NOT LLVM_PROFILE_DATA_DIR)
>>> -      file(TO_NATIVE_PATH "${LLVM_BINARY_DIR}/profiles/%${LLVM_PROFILE_MERGE_POOL_SIZE}m.profraw" LLVM_PROFILE_FILE_PATTERN)
>>> -    else()
>>> -      file(TO_NATIVE_PATH "${LLVM_PROFILE_DATA_DIR}/%${LLVM_PROFILE_MERGE_POOL_SIZE}m.profraw" LLVM_PROFILE_FILE_PATTERN)
>>> +      file(TO_NATIVE_PATH "${LLVM_BINARY_DIR}/profiles" LLVM_PROFILE_DATA_DIR)
>>>     endif()
>>> +		file(TO_NATIVE_PATH "${LLVM_PROFILE_DATA_DIR}/%${LLVM_PROFILE_MERGE_POOL_SIZE}m.profraw" LLVM_PROFILE_FILE_PATTERN)
>>>   endif()
>>> endif()
>>> 
>>> 
>>> Modified: llvm/trunk/cmake/modules/HandleLLVMOptions.cmake
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/cmake/modules/HandleLLVMOptions.cmake?rev=313770&r1=313769&r2=313770&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/cmake/modules/HandleLLVMOptions.cmake (original)
>>> +++ llvm/trunk/cmake/modules/HandleLLVMOptions.cmake Wed Sep 20 10:16:01 2017
>>> @@ -730,13 +730,27 @@ if(LLVM_ENABLE_EH AND NOT LLVM_ENABLE_RT
>>>   message(FATAL_ERROR "Exception handling requires RTTI. You must set LLVM_ENABLE_RTTI to ON")
>>> endif()
>>> 
>>> +option(LLVM_ENABLE_IR_PGO "Build LLVM and tools with IR PGO instrumentation (experimental)" Off)
>>> +mark_as_advanced(LLVM_ENABLE_IR_PGO)
>>> +
>>> option(LLVM_BUILD_INSTRUMENTED "Build LLVM and tools with PGO instrumentation" Off)
>>> mark_as_advanced(LLVM_BUILD_INSTRUMENTED)
>>> -append_if(LLVM_BUILD_INSTRUMENTED "-fprofile-instr-generate='${LLVM_PROFILE_FILE_PATTERN}'"
>>> -  CMAKE_CXX_FLAGS
>>> -  CMAKE_C_FLAGS
>>> -  CMAKE_EXE_LINKER_FLAGS
>>> -  CMAKE_SHARED_LINKER_FLAGS)
>>> +
>>> +if (LLVM_BUILD_INSTRUMENTED)
>>> +  if (LLVM_ENABLE_IR_PGO)
>>> +    append("-fprofile-generate='${LLVM_PROFILE_DATA_DIR}'"
>>> +      CMAKE_CXX_FLAGS
>>> +      CMAKE_C_FLAGS
>>> +      CMAKE_EXE_LINKER_FLAGS
>>> +      CMAKE_SHARED_LINKER_FLAGS)
>>> +  else()
>>> +    append("-fprofile-instr-generate='${LLVM_PROFILE_FILE_PATTERN}'"
>>> +      CMAKE_CXX_FLAGS
>>> +      CMAKE_C_FLAGS
>>> +      CMAKE_EXE_LINKER_FLAGS
>>> +      CMAKE_SHARED_LINKER_FLAGS)
>>> +  endif()
>>> +endif()
>>> 
>>> option(LLVM_BUILD_INSTRUMENTED_COVERAGE "Build LLVM and tools with Code Coverage instrumentation" Off)
>>> mark_as_advanced(LLVM_BUILD_INSTRUMENTED_COVERAGE)
>>> 
>>> 
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