[OE-core] [PATCH] gcc: make sure header path is set correctly

[Mittal, AnujX]

> -----Original Message-----
> From: Khem Raj [mailto:raj.khem at gmail.com]
> Sent: Thursday, June 16, 2016 10:47 AM
> To: Mittal, AnujX <anujx.mittal at intel.com>
> Cc: openembedded-core at lists.openembedded.org
> Subject: Re: [OE-core] [PATCH] gcc: make sure header path is set correctly
> 
> 
> > On Jun 14, 2016, at 2:10 AM, Anuj Mittal <anujx.mittal at intel.com> wrote:
> >
> > We're setting the native header paths in do_configure_prepend,
> > and don't need to set them again here.
> >
> > This results in gcc-target not being able to locate the headers
> > and not being able to detect glibc version, which in turn
> > results in SSP support not getting detected even though it's available
> > in libc.
> >
> 
> what is this being set to in do_conigure_prepend ?
> that value may not be right for target recipe. For target we are setting sysroot to /
> and if we do not have this option set then it will set native-system-headers dir to
> be
> / relative and not cross sysroot relative. So it will use your build hosts installation
> for these headers which is not correct either. Have you looked deeper into why its
> not
> finding ssp support inside the cross sysroot?

It's being set to /usr/include:

	# teach gcc to find correct target includedir when checking libc ssp support
	mkdir -p ${B}/gcc
	echo "NATIVE_SYSTEM_HEADER_DIR = ${SYSTEMHEADERS}" > ${B}/gcc/t-oe
	cat ${S}/gcc/defaults.h | grep -v "\#endif.*GCC_DEFAULTS_H" > ${B}/gcc/defaults.h.new
	cat >>${B}/gcc/defaults.h.new <<_EOF
#define NATIVE_SYSTEM_HEADER_DIR "${SYSTEMHEADERS}"
#define STANDARD_STARTFILE_PREFIX_1 "${SYSTEMLIBS}"
#define STANDARD_STARTFILE_PREFIX_2 "${SYSTEMLIBS1}"
#define SYSTEMLIBS_DIR "${SYSTEMLIBS}"
#endif /* ! GCC_DEFAULTS_H */
_EOF
	mv ${B}/gcc/defaults.h.new ${B}/gcc/defaults.h

Having set NATIVE_SYSTEM_HEADER_DIR again in gcc-target just results in gcc not being able to find features.h at all, which is present in the target sysroot.

Because it's not able to find features.h, it just assumes that glibc version available is 0 and hence disables ssp support. Setting NATIVE_SYSTEM_HEADER_DIR to /usr/include just makes sure that target_system_dir in configure script is set to right header path within target sysroot & it can pick up the right header relative to the sysroot.

When configure option is passed, gcc detects target_system_dir (where features.h is present) to be <build_sysroot>/<build_sysroot>/usr/include instead of <build_sysroot>/usr/include.

I've made sure that its picking up the header from target sysroot rather than my host. My host machine has glibc 2.19 whereas the target sysroot has 2.22

Thanks,
Anuj