[OE-core] [PATCH] Yocto: qt4: Let qmake control some compiler/linker flags

[Marek Vasut]

On Monday, August 11, 2014 at 02:49:16 AM, Otavio Salvador wrote:
> Hello Marek,
> 
> On Thu, Aug 7, 2014 at 12:25 PM, Marek Vasut <marex at denx.de> wrote:
> > In the case of building an Qt application outside of the Yocto
> > build system, we want to make sure that a "debug" configuration
> > of the application does contain debug symbols and is has the
> > compiler optimalization unset. On the other hand, we want to
> > have a "release" build which does not contain the debug symbols
> > and has the compiler optimalization turned on.
> > 
> > The OE_QMAKE_* flags serve to pass all kinds of flags into the
> > qmake-generated Makefile. Currently, we set OE_QMAKE_CFLAGS to
> > be ${CFLAGS} and ditto for CXXFLAGS and LDFLAGS in the SDK
> > toolchain environment script. This poses a problem, since the
> > CFLAGS can contain optimization options (-O*) and even flags to
> > produce debugging info (-g). The LDFLAGS may also contain some
> > harmful flags.
> > 
> > The easy way out is to let qmake's army of configuration files
> > handle the proper configuration of CFLAGS, CXXFLAGS and LDFLAGS
> > for the generated Makefile and don't interfere with qmake's
> > decisions by adding arbitrary flags. This patch completely
> > scrubs OE_QMAKE_C{,XX}FLAGS and leaves only harmless flags in
> > OE_QMAKE_LDFLAGS. With this patch, the behavior is as it is
> > explained in the first paragraph.
> > 
> > Signed-off-by: Marek Vasut <marex at denx.de>
> > Cc: Eric Bénard <eric at eukrea.com>
> 
> I understand your problem however I don't think the solution you found
> is optimal. It does fix the issue you refer in the commit log however
> it also makes difficult for user to "reuse" default SDK flags to test
> the application.

What solution do you propose then?

The default SDK flags effectively disallow qmake to operate correctly -- that 
is, to control the compiler/linker flags.

[...]

Best regards,
Marek Vasut