Qt5 has predefined optimization flags depending if you're building for
size, for debug etc. These flags are defined in
mkspecs/common/gcc-base.conf:
QMAKE_CFLAGS_OPTIMIZE = -O2
QMAKE_CFLAGS_OPTIMIZE_FULL = -O3
QMAKE_CFLAGS_OPTIMIZE_DEBUG = -Og
QMAKE_CFLAGS_OPTIMIZE_SIZE = -Os
Then, in the same file, they use them to set
QMAKE_CFLAGS_RELEASE/QMAKE_CXXFLAGS_RELEASE:
QMAKE_CFLAGS_RELEASE += $$QMAKE_CFLAGS_OPTIMIZE
QMAKE_CXXFLAGS_RELEASE += $$QMAKE_CFLAGS_RELEASE
At this point there is our chance to override QMAKE_CFLAGS_OPTIMIZE_* in
qmake.conf, but it's too late, because QMAKE_CFLAGS_RELEASE is already
set (i.e. -O2) so trying to add or remove QMAKE_CFLAGS_OPTIMIZE (that is
reset now on) from QMAKE_CLAGS_RELEASE in
common/features/default_post.prf won't work:
optimize_size {
!isEmpty(QMAKE_CFLAGS_OPTIMIZE):!isEmpty(QMAKE_CFLAGS_OPTIMIZE_SIZE) {
QMAKE_CFLAGS_RELEASE -= $$QMAKE_CFLAGS_OPTIMIZE
QMAKE_CXXFLAGS_RELEASE -= $$QMAKE_CFLAGS_OPTIMIZE
QMAKE_CFLAGS_RELEASE += $$QMAKE_CFLAGS_OPTIMIZE_SIZE
QMAKE_CXXFLAGS_RELEASE += $$QMAKE_CFLAGS_OPTIMIZE_SIZE
}
} else: optimize_full {
!isEmpty(QMAKE_CFLAGS_OPTIMIZE):!isEmpty(QMAKE_CFLAGS_OPTIMIZE_FULL) {
QMAKE_CFLAGS_RELEASE -= $$QMAKE_CFLAGS_OPTIMIZE
QMAKE_CXXFLAGS_RELEASE -= $$QMAKE_CFLAGS_OPTIMIZE
QMAKE_CFLAGS_RELEASE += $$QMAKE_CFLAGS_OPTIMIZE_FULL
QMAKE_CXXFLAGS_RELEASE += $$QMAKE_CFLAGS_OPTIMIZE_FULL
}
}
So let's reset:
QMAKE_CFLAGS_RELEASE
QMAKE_CFLAGS_DEBUG
QMAKE_CXXFLAGS_RELEASE
QMAKE_CXXFLAGS_DEBUG
in our qmake.conf since the only assignment done in
mkspecs/common/gcc-base.conf only regards optimization.
This package is also affected by BR2_TOOLCHAIN_HAS_GCC_BUG_90620 and
it's been worked around by appending -O0 to CFLAGS/CXXFLAGS. This bug
prevented workaround to work overriding optimization flags, so solving
this also solves workaround problem.
Fixes:
http://autobuild.buildroot.net/results/ada/adaa9b4bcc6f9d2b5e82c479859a07e8abf5cf13/http://autobuild.buildroot.net/results/a83/a83bdd1f3bf309c07abebe871b017c331ed36e67/
Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
Tested-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[Arnout: add a comment to qmake.conf.in]
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
c4a6f974b1