[PATCH v2 0/6] Move gdbsupport to top level

[Christian Biesinger via gdb-patches]

On Thu, Jan 16, 2020 at 1:23 PM Pedro Alves <palves@redhat.com> wrote:
>
> On 1/16/20 5:38 PM, Christian Biesinger wrote:
> > On Thu, Jan 16, 2020 at 11:23 AM Pedro Alves <palves@redhat.com> wrote:
> >>> For that patch, why not just use AM_CFLAGS/AM_CXXFLAGS?
> >>
> >> I was mainly following what GDB does, with:
> >>
> >>  COMPILE.pre = $(CXX) -x c++ $(CXX_DIALECT)
> >>
> >> I guess I was the one who did that, so that's not going to be
> >> a strong explanation.  :-)
> >>
> >> It's just that I feel like the compiler mode is more about
> >> picking a different compiler than about picking some flags
> >> like warnings flags or compilation levels.  I think that
> >> in practice the only difference is that you see the
> >> -std=gnu++11 next to the compiler command:
> >>
> >> $ rm -f selftest.o && make V=1 selftest.o
> >> /opt/gcc-4.8/bin/g++ -std=gnu++11 -DHAVE_CONFIG_H -I. -I/home/pedro/gdb/binutils-gdb/src/gdbsupport  -I/home/pedro/gdb/binutils-gdb/src/gdbsupport/config.h -I/home/pedro/gdb/binutils-gdb/src/gdbsupport/../include -I/home/pedro/gdb/binutils-gdb/src/gdbsupport/../gdb -I../gnulib/import -I/home/pedro/gdb/binutils-gdb/src/gdbsupport/../gnulib/import -I.. -I/home/pedro/gdb/binutils-gdb/src/gdbsupport/..  -I../bfd -I/home/pedro/gdb/binutils-gdb/src/gdbsupport/../bfd   -g3 -O0 -MT selftest.o -MD -MP -MF .deps/selftest.Tpo -c -o selftest.o /home/pedro/gdb/binutils-gdb/src/gdbsupport/selftest.c
> >> mv -f .deps/selftest.Tpo .deps/selftest.Po
> >>
> >> vs, with AM_CFLAGS:
> >>
> >> $ rm -f selftest.o && make V=1 selftest.o
> >> /opt/gcc-4.8/bin/g++ -DHAVE_CONFIG_H -I. -I/home/pedro/gdb/binutils-gdb/src/gdbsupport  -I/home/pedro/gdb/binutils-gdb/src/gdbsupport/config.h -I/home/pedro/gdb/binutils-gdb/src/gdbsupport/../include -I/home/pedro/gdb/binutils-gdb/src/gdbsupport/../gdb -I../gnulib/import -I/home/pedro/gdb/binutils-gdb/src/gdbsupport/../gnulib/import -I.. -I/home/pedro/gdb/binutils-gdb/src/gdbsupport/..  -I../bfd -I/home/pedro/gdb/binutils-gdb/src/gdbsupport/../bfd  -std=gnu++11 -g3 -O0 -MT selftest.o -MD -MP -MF .deps/selftest.Tpo -c -o selftest.o /home/pedro/gdb/binutils-gdb/src/gdbsupport/selftest.c
> >> mv -f .deps/selftest.Tpo .deps/selftest.Po
> >>
> >> AFAICT, overriding CXXFLAGS or CXX in the make invocation works
> >> the same in either case.
> >
> > How so? override is documented to override commandline variables?
> > https://www.gnu.org/software/make/manual/html_node/Override-Directive.html#Override-Directive
> >
>
> Because it is defined in terms of CXX, which gets filled with whatever
> was specified on the command line, I believe:
>
>  override CXX := $(CXX) $(CXX_DIALECT)
>
> I guess I should write instead:
>
>  override CXX += $(CXX_DIALECT)

Oh, yeah, good point. Either way is fine with me.

> > But yes, that's what I was thinking of, and just in general that
> > override seems a bit ugly.
>
> Other than aesthetic reasons, do you see an issue?  I like seeing
> the -std=gnu++11 at the left side of the command invocation,
> basically for quick diagnostics, but that's about my only reason
> for preferring it.

Yeah since the overriding still works, I'm fine with this.

Christian