[Buildroot] [PATCH v2] Enable ccache for cmake packages

[Samuel Martin]

Hi Lucas,

2013/3/22 Luca Ceresoli <luca at lucaceresoli.net>:
> Use the *_ARG1 CMake variables to let CMake use ccache without failing
> in detecting the compiler.
>
> Implementation based on an idea suggested by Samuel Martin.
>
> Signed-off-by: Luca Ceresoli <luca at lucaceresoli.net>
> ---
>
> NOTE! This patch is not yet well tested and may be largely non-optimal.
> Commit with care!
>
> It was a bit tricky to implement, because the CMake-generated Makefiles
> do call cmake without supplying the same commandline arguments that we
> passed to the top-level cmake invocation.
> The solution that I implemented for this issue is to use a tristate
> variable, named USE_CCACHE, that Buildroot passes to cmake:
>  - if set to ON, it triggers the configuration for ccache to be saved
>    in the CMake cache;
>  - if set to OFF, it triggers the no-ccache configuration to be saved
>    in the CMake cache;
>  - if it is not set, this means cmake is not being called directly by
>    Buildroot; in this case it does not set any of the compiler CMake
>    variables, thus using those previously cached.
>
> Changed in v2:
>  - totally reimplemented based on Samuel's suggestion;
>  - added dependency on host-ccache for cmake packages if ccache is
>    enabled.
>
>  package/pkg-cmake.mk |   26 ++++++++++++++++++++++++--
>  1 file changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/package/pkg-cmake.mk b/package/pkg-cmake.mk
> index b2fcd67..3d37502 100644
> --- a/package/pkg-cmake.mk
> +++ b/package/pkg-cmake.mk
> @@ -20,6 +20,13 @@
>  #
>  ################################################################################
>
> +# Options to CMake that are equal for all packages
> +ifeq ($(BR2_CCACHE),y)
> +CMAKE_EXTRA_OPT += -DUSE_CCACHE=ON
> +else
> +CMAKE_EXTRA_OPT += -DUSE_CCACHE=OFF
> +endif
> +
>  ################################################################################
>  # inner-cmake-package -- defines how the configuration, compilation and
>  # installation of a CMake package should be done, implements a few hooks to
> @@ -65,6 +72,7 @@ define $(2)_CONFIGURE_CMDS
>         $$($$(PKG)_CONF_ENV) $(HOST_DIR)/usr/bin/cmake $$($$(PKG)_SRCDIR) \
>                 -DCMAKE_TOOLCHAIN_FILE="$$(HOST_DIR)/usr/share/buildroot/toolchainfile.cmake" \
>                 -DCMAKE_INSTALL_PREFIX="/usr" \
> +               $(CMAKE_EXTRA_OPT) \
Or the inlined if works as well ;)

>                 -DCMAKE_VERBOSE_MAKEFILE=ON \
Ahem... I think this belongs to some debug remains ;)

BTW, with CMake, to switch verbose log, just run: 'VERBOSE=1 make'
In Buildroot, 'make V=1' also works... because of some magics in the
Makefile in the topdir.


>                 $$($$(PKG)_CONF_OPT) \
>         )
> @@ -82,6 +90,7 @@ define $(2)_CONFIGURE_CMDS
>                 -DCMAKE_FIND_ROOT_PATH_MODE_LIBRARY="BOTH" \
>                 -DCMAKE_FIND_ROOT_PATH_MODE_INCLUDE="BOTH" \
>                 -DCMAKE_INSTALL_PREFIX="$$(HOST_DIR)/usr" \
> +               $(CMAKE_EXTRA_OPT) \
>                 $$($$(PKG)_CONF_OPT) \
>         )
>  endef
> @@ -94,6 +103,10 @@ $(2)_DEPENDENCIES ?= $(filter-out $(1),$(patsubst host-host-%,host-%,$(addprefix
>
>  $(2)_DEPENDENCIES += host-cmake
>
> +ifeq ($(BR2_CCACHE),y)
> +$(2)_DEPENDENCIES += host-ccache
> +endif
I don't think this is need since host-ccache is one of the first
target add to the list in the topdir Makefile.

> +
>  #
>  # Build step. Only define it if not already defined by the package .mk
>  # file.
> @@ -191,8 +204,17 @@ $(HOST_DIR)/usr/share/buildroot/toolchainfile.cmake:
>         @mkdir -p $(@D)
>         @echo -en "\
>         set(CMAKE_SYSTEM_NAME Linux)\n\
> -       set(CMAKE_C_COMPILER $(TARGET_CC_NOCCACHE))\n\
> -       set(CMAKE_CXX_COMPILER $(TARGET_CXX_NOCCACHE))\n\
> +       if(DEFINED USE_CCACHE AND USE_CCACHE)\n\
> +               set(CMAKE_ASM_COMPILER $(TARGET_CC_NOCCACHE))\n\
I think it does not hurt to put the CMAKE_ASM_COMPILER definition
outside the if block...

> +               set(CMAKE_C_COMPILER $(CCACHE))\n\
> +               set(CMAKE_CXX_COMPILER $(CCACHE))\n\
> +               set(CMAKE_C_COMPILER_ARG1 $(TARGET_CC_NOCCACHE) CACHE STRING \"\" FORCE)\n\
> +               set(CMAKE_CXX_COMPILER_ARG1 $(TARGET_CXX_NOCCACHE) CACHE STRING \"\" FORCE)\n\
> +       endif(DEFINED USE_CCACHE AND USE_CCACHE)\n\
> +       if(DEFINED USE_CCACHE AND NOT USE_CCACHE)\n\
You can replace the 2 above lines by:
else ()

> +               set(CMAKE_C_COMPILER $(TARGET_CC_NOCCACHE))\n\
> +               set(CMAKE_CXX_COMPILER $(TARGET_CXX_NOCCACHE))\n\
> +       endif(DEFINED USE_CCACHE AND NOT USE_CCACHE)\n\
>         set(CMAKE_C_FLAGS \"\$${CMAKE_C_FLAGS} $(TARGET_CFLAGS)\" CACHE STRING \"Buildroot CFLAGS\" FORCE)\n\
>         set(CMAKE_CXX_FLAGS \"\$${CMAKE_CXX_FLAGS} $(TARGET_CXXFLAGS)\" CACHE STRING \"Buildroot CXXFLAGS\" FORCE)\n\
>         set(CMAKE_INSTALL_SO_NO_EXE 0)\n\
> --
> 1.7.10.4
>

I have not tested this patch but something really close, nor done
extensive tests, but I expect it will works fine.


Regards,

-- 
Samuel