[Buildroot] [PATCH] pacakge/qt5/qt5base: fix build with ccache

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Beno?t,

On Tue, 25 Aug 2015 12:41:38 +0200, Beno?t Th?baudeau wrote:
> Building with ccache failed with:
> 
>     Running configuration tests...
>     Failed to process makespec for platform 'devices/linux-buildroot-g++'
>     Project ERROR: Compiler <path_to_output_dir>/host/usr/bin/ccache <path_to_output_dir>/host/usr/bin/<cross_compile>-g++ not found. Check the value of CROSS_COMPILE -device-option
>     Could not read qmake configuration file <path_to_output_dir>/build/qt5base-5.5.0/mkspecs/devices/linux-buildroot-g++/qmake.conf.
>     Error processing project file: /dev/null
> 
> This was caused by Buildroot setting this in
> qt5base-5.5.0/mkspecs/devices/linux-buildroot-g++/qmake.conf:
> 
>     QMAKE_CXX               = $${BR_CCACHE} $${CROSS_COMPILE}g++
> 
> But qt5base-5.5.0/mkspecs/features/device_config.prf expects QMAKE_CXX
> to be a valid (absolute or QMAKE_PATH_ENV-relative) path to an existing
> file, which is not possible if using ccache as above.
> 
> Add a patch removing these tests since the toolchain is already tested
> by Buildroot, which allows to keep using ccache.
> 
> Signed-off-by: Beno?t Th?baudeau <benoit@wsystem.com>

Thanks for the patch. I see the problem, but as usual, having a
solution that can be submitted upstream is better. See my suggestion
below.

> ---
>  .../qt5/qt5base/0009-fix-build-with-ccache.patch   | 60 ++++++++++++++++++++++
>  1 file changed, 60 insertions(+)
>  create mode 100644 package/qt5/qt5base/0009-fix-build-with-ccache.patch
> 
> diff --git a/package/qt5/qt5base/0009-fix-build-with-ccache.patch b/package/qt5/qt5base/0009-fix-build-with-ccache.patch
> new file mode 100644
> index 0000000..04d41a4
> --- /dev/null
> +++ b/package/qt5/qt5base/0009-fix-build-with-ccache.patch
> @@ -0,0 +1,60 @@
> +Fix build with ccache
> +
> +Building with Buildroot and ccache failed with:
> +
> +    Running configuration tests...
> +    Failed to process makespec for platform 'devices/linux-buildroot-g++'
> +    Project ERROR: Compiler <path_to_output_dir>/host/usr/bin/ccache <path_to_output_dir>/host/usr/bin/<cross_compile>-g++ not found. Check the value of CROSS_COMPILE -device-option
> +    Could not read qmake configuration file <path_to_output_dir>/build/qt5base-5.5.0/mkspecs/devices/linux-buildroot-g++/qmake.conf.
> +    Error processing project file: /dev/null
> +
> +This was caused by Buildroot setting this in
> +qt5base-5.5.0/mkspecs/devices/linux-buildroot-g++/qmake.conf:
> +
> +    QMAKE_CXX               = $${BR_CCACHE} $${CROSS_COMPILE}g++
> +
> +But qt5base-5.5.0/mkspecs/features/device_config.prf expects QMAKE_CXX
> +to be a valid (absolute or QMAKE_PATH_ENV-relative) path to an existing
> +file, which is not possible if using ccache as above.
> +
> +Remove these tests since the toolchain is already tested by Buildroot,
> +which allows to keep using ccache.
> +
> +Signed-off-by: Beno?t Th?baudeau <benoit@wsystem.com>
> +---
> + mkspecs/features/device_config.prf | 23 -----------------------
> + 1 file changed, 23 deletions(-)
> +
> +diff --git a/mkspecs/features/device_config.prf b/mkspecs/features/device_config.prf
> +index cd3a0cf..ef16540 100644
> +--- a/mkspecs/features/device_config.prf
> ++++ b/mkspecs/features/device_config.prf
> +@@ -14,28 +14,5 @@ host_build {
> + 
> + # Provide a function to be used by mkspecs
> + defineTest(deviceSanityCheckCompiler) {
> +-    equals(QMAKE_HOST.os, Windows): \
> +-        sfx = .exe
> +-    else: \
> +-        sfx =
> +-
> +-    # Check if the binary exists with an absolute path. Do this check
> +-    # before the CROSS_COMPILE empty check below to allow the mkspec
> +-    # to derive the compiler path from other device options.
> +-    exists($$QMAKE_CXX$$sfx):return()
> +-
> +-    # Check for possible reasons of failure
> +-    # check if CROSS_COMPILE device-option is set
> +-    isEmpty(CROSS_COMPILE):error("CROSS_COMPILE needs to be set via -device-option CROSS_COMPILE=<path>")
> +-
> +-    # Check if QMAKE_CXX points to an executable.
> +-    ensurePathEnv()
> +-    for (dir, QMAKE_PATH_ENV) {
> +-        exists($$dir/$${QMAKE_CXX}$$sfx): \
> +-            return()
> +-    }

Instead of removing this entire piece of code, can you try to replace
just this last part by something like:

	system($${QMAKE_CXX}$$sfx --version): return()

Instead of trying to look for a file, it will actually try to run the
compiler.

Also, can you report the bug and submit the patch upstream to Qt? See
https://bugreports.qt.io/secure/Dashboard.jspa.

Thanks!

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com