[Buildroot] [PATCH] Don't build host-cmake if it is available on the build host

[Luca Ceresoli <luca@lucaceresoli.net>]

Hi Arnout,

thanks for the review.

Unfortunately this patch is not working, at least for qjson with qt4.

qjson fails with:

CMake Error in src/CMakeLists.txt:
   Imported target "Qt4::QtCore" includes non-existent path

     "QT_MKSPECS_DIR-NOTFOUND/default"

   in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:

   * The path was deleted, renamed, or moved to another location.

   * An install or uninstall procedure did not complete successfully.

   * The installation package was faulty and references files it does not
   provide.

I am investigating right now.

Below my replies to your comments.

Arnout Vandecappelle wrote:
> On 01-02-16 22:44, Luca Ceresoli wrote:
>> Currently all cmake packages depend on host-cmake. Unfortunately
>> host-cmake takes a long time to configure and build: almost 7 minutes
>> on a dual-core i5 with SSD. The time does not change even with ccache
>> enabled.
>>
>> Indeed, building host-ccache is not very useful if it is already
>
>   host-ccache -> host-cmake

Oops. :)

>
>> installed on the build host: it is supposed to be quite portable, and
>> the only patch we have for cmake seems to only affect target-cmake.
>>
>> We avoid building host-cmake if cmake is already available on the host
>> using a technique similar to the one used for host-tar and host-xzcat.
>>
>> First, we leverage the existing infrastructure in
>> support/dependencies/dependencies.mk to set CMAKE to either "cmake" or
>> "$(HOST_DIR)/usr/bin/cmake". In the latter case we also set
>> BUILD_HOST_CMAKE = YES meaning we need to build host-cmake.
>>
>> Then in pkg-cmake.mk we launch $(CMAKE) instead of
>> $(HOST_DIR)/usr/bin/cmake.
>>
>> Finally, we do skip adding the dependency on host-cmake for all cmake
>> packages when $(BUILD_HOST_CMAKE) != YES.
>>
>> Unlike what we do for host-tar and host-xzcat, for host-cmake we do
>> not add host-cmake to DEPENDENCIES_HOST_PREREQ. Otherwise host-cmake
>> would be a dependency for _any_ package when it's not installed on the
>> host, even if no cmake package is selected.
>
>   Nice and long commit message, thanks!
>
>>
>> Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
>> Cc: Samuel Martin <s.martin49@gmail.com>
>> Cc: Davide Viti <zinosat@tiscali.it>
>> ---
>>   package/pkg-cmake.mk                     |  6 ++++--
>>   support/dependencies/check-host-cmake.mk |  6 ++++++
>>   support/dependencies/check-host-cmake.sh | 14 ++++++++++++++
>>   3 files changed, 24 insertions(+), 2 deletions(-)
>>   create mode 100644 support/dependencies/check-host-cmake.mk
>>   create mode 100755 support/dependencies/check-host-cmake.sh
>>
>> diff --git a/package/pkg-cmake.mk b/package/pkg-cmake.mk
>> index 81dcfcc..e3bd603 100644
>> --- a/package/pkg-cmake.mk
>> +++ b/package/pkg-cmake.mk
>> @@ -85,7 +85,7 @@ define $(2)_CONFIGURE_CMDS
>>   	cd $$($$(PKG)_BUILDDIR) && \
>>   	rm -f CMakeCache.txt && \
>>   	PATH=$$(BR_PATH) \
>> -	$$($$(PKG)_CONF_ENV) $$(HOST_DIR)/usr/bin/cmake $$($$(PKG)_SRCDIR) \
>> +	$$($$(PKG)_CONF_ENV) $$(CMAKE) $$($$(PKG)_SRCDIR) \
>>   		-DCMAKE_TOOLCHAIN_FILE="$$(HOST_DIR)/usr/share/buildroot/toolchainfile.cmake" \
>>   		-DCMAKE_BUILD_TYPE=$$(if $$(BR2_ENABLE_DEBUG),Debug,Release) \
>>   		-DCMAKE_INSTALL_PREFIX="/usr" \
>> @@ -110,7 +110,7 @@ define $(2)_CONFIGURE_CMDS
>>   	cd $$($$(PKG)_BUILDDIR) && \
>>   	rm -f CMakeCache.txt && \
>>   	PATH=$$(BR_PATH) \
>> -	$$(HOST_DIR)/usr/bin/cmake $$($$(PKG)_SRCDIR) \
>> +	$$(CMAKE) $$($$(PKG)_SRCDIR) \
>>   		-DCMAKE_INSTALL_SO_NO_EXE=0 \
>>   		-DCMAKE_FIND_ROOT_PATH="$$(HOST_DIR)" \
>>   		-DCMAKE_FIND_ROOT_PATH_MODE_PROGRAM="BOTH" \
>> @@ -149,7 +149,9 @@ $(2)_DEPENDENCIES ?= $$(filter-out host-skeleton host-toolchain $(1),\
>>   	$$(patsubst host-host-%,host-%,$$(addprefix host-,$$($(3)_DEPENDENCIES))))
>>   endif
>>
>> +ifeq ($$(BUILD_HOST_CMAKE),YES)
>>   $(2)_DEPENDENCIES += host-cmake
>> +endif
>>
>>   #
>>   # Build step. Only define it if not already defined by the package .mk
>> diff --git a/support/dependencies/check-host-cmake.mk b/support/dependencies/check-host-cmake.mk
>> new file mode 100644
>> index 0000000..fe16322
>> --- /dev/null
>> +++ b/support/dependencies/check-host-cmake.mk
>> @@ -0,0 +1,6 @@
>> +CMAKE ?= cmake
>> +
>> +ifeq (,$(call suitable-host-package,cmake,$(CMAKE)))
>> +BUILD_HOST_CMAKE = YES
>> +CMAKE = $(HOST_DIR)/usr/bin/cmake
>> +endif
>> diff --git a/support/dependencies/check-host-cmake.sh b/support/dependencies/check-host-cmake.sh
>> new file mode 100755
>> index 0000000..76a81e0
>> --- /dev/null
>> +++ b/support/dependencies/check-host-cmake.sh
>> @@ -0,0 +1,14 @@
>> +#!/bin/sh
>> +
>> +candidate="$1"
>> +
>> +cmake=`which $candidate`
>
>   $candidate could be an absolute path, in which case which returns nothing.
>
>> +if [ ! -x "$cmake" ]; then
>> +	cmake=`which cmake`
>
>   Since there is already CMAKE ?= cmake in the caller, this is pointless.
>
>   How about a
>
> for cmake in "$cmake" "$( which "$cmake" )"; do
>   ...
>
> instead?

Your suggestions are absolutely correct. I shamelessly copied other
check-host-*.sh scripts and just concentrated on having the thing
working. Seems like thos other script need a cleanup now. I'll have a
look (if/after I can make this thing working).

>
>> +	if [ ! -x "$cmake" ]; then
>> +		# echo nothing: no suitable cmake found
>> +		exit 1
>> +	fi
>> +fi
>
>   I have the feeling that there should also be a version check here, though I
> don't know which version we should use.

Right. My idea is to download all the cmake packages that are currently
in Buildroot, find the highest version mentioned in their
CMAKE_MINIMUM_REQUIRED() statement and check for that version in the
script.

-- 
Luca