Re: [CMake] Cross-compiling, CMAKE_C_FLAGS, and configure-time compiler tests
Hi Justin,
On Tuesday 14 December 2010, Justin Holewinski wrote:
On Tue, Dec 14, 2010 at 4:45 AM, Johan Björk p...@spotify.com wrote:
Hi Justin,
I'm very unsure if this is the correct solution, but it worked for me. I
haven't been able to find any good documentation stating how the
CMakeCache interacts with other parts of CMake.
My assumption is that since CMAKE_C{XX}_FLAGS is supposed to allow the
user to set optional compilation flags, it prefers the value in the cache
versus the one from the toolchain file.
From one of my toolchain files, reproduce as necessary for CMAKE_C_FLAGS:
SET(CMAKE_CXX_FLAGS ${CMAKE_C_FLAGS} -fno-rtti CACHE STRING FORCE)
I'll have to give that a try. For now, I'm getting around the problem by
setting the flags within the parent CMakeLists.txt script after loading the
toolchain file.
I'm really not sure what the best practice is for this situation. The
compiler will work and can be tested without the -arch flags, but the
flags are necessary to build for the *right* architecture. Most
cross-compilers will only produce binaries for the target system, so the
point is moot. The iOS compilers, however, will generate code for Intel
and ARM so I'm not sure if testing the i386 back-end when I'm targeting ARM
is the right way or not.
please put your problem in the cmake bug tracker
http://public.kitware.com/Bug/ and assign it to me.
Thanks
Alex
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Re: [CMake] Cross-compiling, CMAKE_C_FLAGS, and configure-time compiler tests
Hi Justin,
I'm very unsure if this is the correct solution, but it worked for me. I
haven't been able to find any good documentation stating how the CMakeCache
interacts with other parts of CMake.
My assumption is that since CMAKE_C{XX}_FLAGS is supposed to allow the user
to set optional compilation flags, it prefers the value in the cache versus
the one from the toolchain file.
From one of my toolchain files, reproduce as necessary for CMAKE_C_FLAGS:
SET(CMAKE_CXX_FLAGS ${CMAKE_C_FLAGS} -fno-rtti CACHE STRING FORCE)
Cheers
/Johan
On Mon, Dec 13, 2010 at 4:49 PM, Justin Holewinski
justin.holewin...@gmail.com wrote:
I am experiencing a cross-compiling issue that I believe is related to how
toolchain files interact with the configure-time compiler checks. For
reference, I am targeting the iOS 4.2 SDK. I have a toolchain file that
sets CMAKE_C_FLAGS, CMAKE_CXX_FLAGS, CMAKE_C_LINK_FLAGS, and
CMAKE_CXX_LINK_FLAGS with appropriate flags for the iOS platform, in
particular -arch armv6 -arch armv7. The toolchain file also sets the
proper C and C++ compilers.
When CMake is executed and the C compiler is tested, the
toolchain-specified compiler arguments are passed to the link line, but
*not* the compile line (according to the error output). Since the compile
line does not contain the -arch arguments, the generated object file is
for i386. However, since the link line contains these flags, the linker
tries to link ARM code and fails.
Are there any additional variables I should be setting in addition to
CMAKE_C_FLAGS and CMAKE_CXX_FLAGS in order to get the compiler tests to use
the right flags? If I add the -arch flags using ADD_DEFINITIONS(), they
are passed to the compiler test and it succeeds. That seems like a hack and
not a proper solution, though.
Below is the CMake output that prints the values of CMAKE_*_FLAGS as set by
the toolchain file, as well as the compile and link lines used by CMake.
I am using CMake 2.8.3 on Snow Leopard 10.6.5.
CMake Output:
-- CMAKE_C_FLAGS:-arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- CMAKE_CXX_FLAGS -arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- CMAKE_C_LINK_FLAGS-arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- CMAKE_CXX_LINK_FLAGS -arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- CMAKE_C_FLAGS:-arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- CMAKE_CXX_FLAGS -arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- CMAKE_C_LINK_FLAGS-arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- CMAKE_CXX_LINK_FLAGS -arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- The C compiler identification is GNU
-- The CXX compiler identification is GNU
-- Check for working C compiler:
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2
-- Check for working C compiler:
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2 -- broken
CMake Error at
/opt/local/share/cmake-2.8/Modules/CMakeTestCCompiler.cmake:52 (MESSAGE):
The C compiler
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2 is not
able to compile a simple test program.
It fails with the following output:
Change Dir:
/Users/jholewinski/projects/rapture/build-test/ios/CMakeFiles/CMakeTmp
Run Build Command:/usr/bin/make cmTryCompileExec/fast
/usr/bin/make -f CMakeFiles/cmTryCompileExec.dir/build.make
CMakeFiles/cmTryCompileExec.dir/build
/opt/local/bin/cmake -E cmake_progress_report
/Users/jholewinski/projects/rapture/build-test/ios/CMakeFiles/CMakeTmp/CMakeFiles
1
Building C object CMakeFiles/cmTryCompileExec.dir/testCCompiler.c.obj
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2
-I/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk/usr/include
-o CMakeFiles/cmTryCompileExec.dir/testCCompiler.c.obj -c
/Users/jholewinski/projects/rapture/build-test/ios/CMakeFiles/CMakeTmp/testCCompiler.c
Linking C executable cmTryCompileExec
/opt/local/bin/cmake -E cmake_link_script
CMakeFiles/cmTryCompileExec.dir/link.txt --verbose=1
Re: [CMake] Cross-compiling, CMAKE_C_FLAGS, and configure-time compiler tests
On Tue, Dec 14, 2010 at 4:45 AM, Johan Björk p...@spotify.com wrote:
Hi Justin,
I'm very unsure if this is the correct solution, but it worked for me. I
haven't been able to find any good documentation stating how the CMakeCache
interacts with other parts of CMake.
My assumption is that since CMAKE_C{XX}_FLAGS is supposed to allow the user
to set optional compilation flags, it prefers the value in the cache versus
the one from the toolchain file.
From one of my toolchain files, reproduce as necessary for CMAKE_C_FLAGS:
SET(CMAKE_CXX_FLAGS ${CMAKE_C_FLAGS} -fno-rtti CACHE STRING FORCE)
I'll have to give that a try. For now, I'm getting around the problem by
setting the flags within the parent CMakeLists.txt script after loading the
toolchain file.
I'm really not sure what the best practice is for this situation. The
compiler will work and can be tested without the -arch flags, but the
flags are necessary to build for the *right* architecture. Most
cross-compilers will only produce binaries for the target system, so the
point is moot. The iOS compilers, however, will generate code for Intel and
ARM so I'm not sure if testing the i386 back-end when I'm targeting ARM is
the right way or not.
Cheers
/Johan
On Mon, Dec 13, 2010 at 4:49 PM, Justin Holewinski
justin.holewin...@gmail.com wrote:
I am experiencing a cross-compiling issue that I believe is related to how
toolchain files interact with the configure-time compiler checks. For
reference, I am targeting the iOS 4.2 SDK. I have a toolchain file that
sets CMAKE_C_FLAGS, CMAKE_CXX_FLAGS, CMAKE_C_LINK_FLAGS, and
CMAKE_CXX_LINK_FLAGS with appropriate flags for the iOS platform, in
particular -arch armv6 -arch armv7. The toolchain file also sets the
proper C and C++ compilers.
When CMake is executed and the C compiler is tested, the
toolchain-specified compiler arguments are passed to the link line, but
*not* the compile line (according to the error output). Since the compile
line does not contain the -arch arguments, the generated object file is
for i386. However, since the link line contains these flags, the linker
tries to link ARM code and fails.
Are there any additional variables I should be setting in addition to
CMAKE_C_FLAGS and CMAKE_CXX_FLAGS in order to get the compiler tests to use
the right flags? If I add the -arch flags using ADD_DEFINITIONS(), they
are passed to the compiler test and it succeeds. That seems like a hack and
not a proper solution, though.
Below is the CMake output that prints the values of CMAKE_*_FLAGS as set
by the toolchain file, as well as the compile and link lines used by CMake.
I am using CMake 2.8.3 on Snow Leopard 10.6.5.
CMake Output:
-- CMAKE_C_FLAGS:-arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- CMAKE_CXX_FLAGS -arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- CMAKE_C_LINK_FLAGS-arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- CMAKE_CXX_LINK_FLAGS -arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- CMAKE_C_FLAGS:-arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- CMAKE_CXX_FLAGS -arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- CMAKE_C_LINK_FLAGS-arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- CMAKE_CXX_LINK_FLAGS -arch armv6 -arch armv7 -pipe -no-cpp-precomp
--sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.2.sdk
-miphoneos-version-min=4.2
-- The C compiler identification is GNU
-- The CXX compiler identification is GNU
-- Check for working C compiler:
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2
-- Check for working C compiler:
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2 -- broken
CMake Error at
/opt/local/share/cmake-2.8/Modules/CMakeTestCCompiler.cmake:52 (MESSAGE):
The C compiler
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2 is
not
able to compile a simple test program.
It fails with the following output:
Change Dir:
/Users/jholewinski/projects/rapture/build-test/ios/CMakeFiles/CMakeTmp
Run Build Command:/usr/bin/make cmTryCompileExec/fast
/usr/bin/make -f CMakeFiles/cmTryCompileExec.dir/build.make
CMakeFiles/cmTryCompileExec.dir/build
