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https://github.com/warmcat/libwebsockets.git
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b50e9fb31b
The cmake config on the build system actually decides the release build optimization policy. On Fedora, it's -O2. On Ubuntu, it's -O3. Anything given in CMakeLists.txt is overridden by the build system policy since it goes at the end of the compiler commandline. When you are building cross, the build system's opinion of your cross binary optimization level is irrelevant, and at worst destructive. Some versions of gcc contain broken optimizations that are applied only at -O3. This patch removes any doomed attempt to set -O in CMakeLists.txt, which has no effect since the build system policy is still added at the end, but removes confusion; and adds code to all the cross build files to forcibly override release optimization level to -O2, removing the build system's opinion of how your cross build should look.
46 lines
1.7 KiB
CMake
46 lines
1.7 KiB
CMake
#
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# CMake Toolchain file for crosscompiling on ARM.
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#
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# This can be used when running cmake in the following way:
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# cd build/
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# cmake .. -DCMAKE_TOOLCHAIN_FILE=../cross-arm-linux-gnueabihf.cmake
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#
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set(CROSS_PATH /opt/libwebsockets_android/android-toolchain-arm)
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# Target operating system name.
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set(CMAKE_SYSTEM_NAME Android)
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# Target build dynamic libs.
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set(BUILD_SHARED_LIBS ON)
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# Name of C compiler.
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set(CMAKE_C_COMPILER "${CROSS_PATH}/bin/arm-linux-androideabi-gcc")
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set(CMAKE_CXX_COMPILER "${CROSS_PATH}/bin/arm-linux-androideabi-g++")
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#
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# Different build system distros set release optimization level to different
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# things according to their local policy, eg, Fedora is -O2 and Ubuntu is -O3
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# here. Actually the build system's local policy is completely unrelated to
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# our desire for cross-build release optimization policy for code built to run
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# on a completely different target than the build system itself.
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#
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# Since this goes last on the compiler commandline we have to override it to a
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# sane value for cross-build here. Notice some gcc versions enable broken
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# optimizations with -O3.
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#
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if (CMAKE_BUILD_TYPE MATCHES RELEASE OR CMAKE_BUILD_TYPE MATCHES Release OR CMAKE_BUILD_TYPE MATCHES release)
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set(CMAKE_C_FLAGS_RELEASE ${CMAKE_C_FLAGS_RELEASE}" -O2")
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set(CMAKE_CXX_FLAGS_RELEASE ${CMAKE_CXX_FLAGS_RELEASE}" -O2")
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endif()
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# Where to look for the target environment. (More paths can be added here)
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set(CMAKE_FIND_ROOT_PATH "${CROSS_PATH}")
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# Adjust the default behavior of the FIND_XXX() commands:
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# search programs in the host environment only.
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set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
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# Search headers and libraries in the target environment only.
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set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
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set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
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