[Buildroot] [PATCH 4/4] toolchainfile.cmake: set CXX variables wrt BR2_INSTALL_LIBSTDCPP value
Thomas Petazzoni
thomas.petazzoni at free-electrons.com
Mon Mar 16 21:24:58 UTC 2015
Dear Samuel Martin,
On Sun, 8 Mar 2015 10:47:23 +0100, Samuel Martin wrote:
> Signed-off-by: Samuel Martin <s.martin49 at gmail.com>
This is a non-trivial patch, and the commit log is empty. Why?
> diff --git a/support/misc/toolchainfile.cmake.in b/support/misc/toolchainfile.cmake.in
> index cd41254..395cf3f 100644
> --- a/support/misc/toolchainfile.cmake.in
> +++ b/support/misc/toolchainfile.cmake.in
> @@ -17,6 +17,7 @@ set(CMAKE_C_FLAGS "@@TARGET_CFLAGS@@ ${CMAKE_C_FLAGS}" CACHE STRING "Buildroot C
> set(CMAKE_CXX_FLAGS "@@TARGET_CXXFLAGS@@ ${CMAKE_CXX_FLAGS}" CACHE STRING "Buildroot CXXFLAGS")
> set(CMAKE_EXE_LINKER_FLAGS "@@TARGET_LDFLAGS@@ ${CMAKE_EXE_LINKER_FLAGS}" CACHE STRING "Buildroot LDFLAGS")
> set(CMAKE_INSTALL_SO_NO_EXE 0)
> +set(TARGET_HAS_LIBSTDCXX @@TARGET_HAS_LIBSTDCXX@@)
>
> set(CMAKE_PROGRAM_PATH "${RELOCATED_HOST_DIR}/usr/bin")
> set(CMAKE_FIND_ROOT_PATH "${RELOCATED_HOST_DIR}/@@STAGING_SUBDIR@@")
> @@ -35,25 +36,45 @@ if(DEFINED USE_CCACHE)
> if(USE_CCACHE)
> set(CMAKE_ASM_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CC_NOCCACHE@@")
> set(CMAKE_C_COMPILER "${RELOCATED_HOST_DIR}/usr/bin/ccache")
> - set(CMAKE_CXX_COMPILER "${RELOCATED_HOST_DIR}/usr/bin/ccache")
> set(CMAKE_C_COMPILER_ARG1 "${RELOCATED_HOST_DIR}/@@TARGET_CC_NOCCACHE@@")
> - set(CMAKE_CXX_COMPILER_ARG1 "${RELOCATED_HOST_DIR}/@@TARGET_CXX_NOCCACHE@@")
> + if(TARGET_HAS_LIBSTDCXX)
> + set(CMAKE_CXX_COMPILER "${RELOCATED_HOST_DIR}/usr/bin/ccache")
> + set(CMAKE_CXX_COMPILER_ARG1 "${RELOCATED_HOST_DIR}/@@TARGET_CXX_NOCCACHE@@")
> + else()
> + message(STATUS "Disabling C++ compiler because libstdc++ is not installed in the target filsystem")
> + set(CMAKE_CXX_COMPILER "CMAKE_CXX_COMPILER-NOTFOUND")
> + endif()
> else()
> set(CMAKE_C_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CC_NOCCACHE@@")
> - set(CMAKE_CXX_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CXX_NOCCACHE@@")
> + if(TARGET_HAS_LIBSTDCXX)
> + set(CMAKE_CXX_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CXX_NOCCACHE@@")
> + else()
> + message(STATUS "Disabling C++ compiler because libstdc++ is not installed in the target filsystem")
> + set(CMAKE_CXX_COMPILER "CMAKE_CXX_COMPILER-NOTFOUND")
> + endif()
> endif()
> else()
> find_program(CCACHE ccache HINTS "${RELOCATED_HOST_DIR}/usr/bin")
> if(CCACHE)
> set(CMAKE_ASM_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CC_NOCCACHE@@")
> set(CMAKE_C_COMPILER "${CCACHE}")
> - set(CMAKE_CXX_COMPILER "${CCACHE}")
> set(CMAKE_C_COMPILER_ARG1 "${RELOCATED_HOST_DIR}/@@TARGET_CC_NOCCACHE@@")
> - set(CMAKE_CXX_COMPILER_ARG1 "${RELOCATED_HOST_DIR}/@@TARGET_CXX_NOCCACHE@@")
> + if(TARGET_HAS_LIBSTDCXX)
> + set(CMAKE_CXX_COMPILER "${CCACHE}")
> + set(CMAKE_CXX_COMPILER_ARG1 "${RELOCATED_HOST_DIR}/@@TARGET_CXX_NOCCACHE@@")
> + else()
> + message(STATUS "Disabling C++ compiler because libstdc++ is not installed in the target filsystem")
> + set(CMAKE_CXX_COMPILER "CMAKE_CXX_COMPILER-NOTFOUND")
> + endif()
> message(STATUS "ccache program has been found and will be used for the build.")
> message(STATUS " To disable ccache, add -DUSE_CCACHE=OFF on the cmake command line.")
> else()
> set(CMAKE_C_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CC_NOCCACHE@@")
> - set(CMAKE_CXX_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CXX_NOCCACHE@@")
> + if(TARGET_HAS_LIBSTDCXX)
> + set(CMAKE_CXX_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CXX_NOCCACHE@@")
> + else()
> + message(STATUS "Disabling C++ compiler because libstdc++ is not installed in the target filsystem")
> + set(CMAKE_CXX_COMPILER "CMAKE_CXX_COMPILER-NOTFOUND")
> + endif()
> endif()
> endif()
This is doing multiple times the same thing.
First of all, why do we have those two cases for the ccache support:
if(DEFINED USE_CCACHE)
if(USE_CCACHE)
...
else()
...
endif()
else()
find_program(CCACHE ccache HINTS "${RELOCATED_HOST_DIR}/usr/bin")
if(CCACHE)
...
else()
...
endif()
endif()
The first case is when the toolchain file is used by Buildroot itself,
the second case when it's used outside of Buildroot. But why don't we
use the find_program() trick in both cases ?
Shouldn't we instead do:
find_program(CCACHE ccache HINTS "${RELOCATED_HOST_DIR}/usr/bin")
if (CCACHE and USE_CCACHE)
...
else()
...
endif()
Regarding the C++ stuff, the non-C++ case is the same between having
ccache and not having ccache, so you could factorize that a bit.
Could you rework this a bit?
Thanks a lot,
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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