Re: -static-pie and -static -pie

[Szabolcs Nagy <szabolcs dot nagy at arm dot com>]

On 31/01/18 15:44, Cory Fields wrote:
> After looking at this for quite a while, I'm afraid I'm unsure how to proceed.
>
> As of now, static and static-pie are mutually exclusive. So given the
> GNU_USER_TARGET_STARTFILE_SPEC you pasted
> earlier, "static" matches before "static-pie", causing the wrong start files.
>
> It seems to me that the static-pie target complicates things more than
> matching against static+pie individually.
>
> If I convert -static + -pie to -static-pie, then "static" won't be
> matched in specs, where maybe it otherwise should. Same for -pie.

you can change PIE_SPEC to pie|static-pie
and occurrences of static to static|static-pie
(and !static: to !static:%{!static-pie: etc.),
except where it is used to mean "no-pie static",
those should be changed to PIE_SPEC:;static:
(and i think --no-dynamic-linker should always
be passed to ld in LD_PIE_SPEC for static pie,
not just on linux systems and selected targets.)

then there should be no difference between -static -pie
and -static-pie. (and the new -static-pie flag would
be redundant.)

this would e.g. break static linking with default pie
toolchain on systems where the static libc is not pie
or missing the rcrt startup file after upgrading to gcc-8.
i'm not sure if this is a good enough reason to introduce
the -static-pie mess, however if we don't want to break
any previously working configuration then -static-pie has
to be different from -static -pie.

> Would you prefer to swallow -static and -pie and pass along only
> -static-pie? Or forward them all along, and fix the specs which look
> for static before static-pie ?
>
> Regards,
> Cory
>
> On Tue, Jan 30, 2018 at 2:36 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> > On Tue, Jan 30, 2018 at 11:18 AM, Cory Fields <lists@coryfields.com> wrote:
> > > On Tue, Jan 30, 2018 at 2:14 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> > > > On Tue, Jan 30, 2018 at 11:07 AM, Cory Fields <lists@coryfields.com> wrote:
> > > > > On Tue, Jan 30, 2018 at 1:35 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> > > > > > On Tue, Jan 30, 2018 at 10:26 AM, Cory Fields <lists@coryfields.com> wrote:
> > > > > > > Hi list
> > > > > > >
> > > > > > > I'm playing with -static-pie and musl, which seems to be in good shape
> > > > > > > for 8.0.0. Nice work :)
> > > > > > >
> > > > > > > However, the fact that "gcc -static -pie" and "gcc -static-pie"
> > > > > > > produce different results is very unexpected. I understand the case
> > > > > > > for the new link-type, but merging the options when possible would be
> > > > > > > a huge benefit to existing buildsystems that already cope with both
> > > > > > > individually.
> > > > > > >
> > > > > > > My use-case:
> > > > > > > I'd like to build with --enable-default-pie, and by adding "-static"
> > > > > >
> > > > > > Why not adding "-static-pie" instead of "-static"?
> > > > > >
> > > > > > > to my builds, produce static-pie binaries. But at the moment, that
> > > > > > > attempts to add an interp section.
> > > > > > >
> > > > > > > So my question is, if no conflicting options are found, why not hoist
> > > > > > > "-static -pie" to "-static-pie" ?
> > > > > > >
> > > > > > > Regards,
> > > > > > > Cory
> > > > > >
> > > > > >
> > > > > >
> > > > > > --
> > > > > > H.J.
> > > > >
> > > > > My build system, and plenty of others I'm sure, already handle -static
> > > > > and -pie. Having that understood to mean "static-pie" would mean that
> > > > > the combination would now just work.
> > > > >
> > > > > Asking a different way, if I request -static and -pie, without -nopie,
> > > > > quietly creating non-pie binary seems like a bug. Is there a reason
> > > > > _not_ to interpret it as -static-pie in that case?
> > > >
> > > > GNU_USER_TARGET_STARTFILE_SPEC is defined as
> > > >
> > > > #define GNU_USER_TARGET_STARTFILE_SPEC \
> > > >    "%{shared:; \
> > > >       pg|p|profile:%{static-pie:grcrt1.o%s;:gcrt1.o%s}; \
> > > >       static:crt1.o%s; \
> > > >       static-pie:rcrt1.o%s; \
> > > >       " PIE_SPEC ":Scrt1.o%s; \
> > > >       :crt1.o%s} \
> > > >     crti.o%s \
> > > >     %{static:crtbeginT.o%s; \
> > > >       shared|static-pie|" PIE_SPEC ":crtbeginS.o%s; \
> > > >       :crtbegin.o%s} \
> > > >     %{fvtable-verify=none:%s; \
> > > >       fvtable-verify=preinit:vtv_start_preinit.o%s; \
> > > >       fvtable-verify=std:vtv_start.o%s} \
> > > >     " CRTOFFLOADBEGIN
> > > >
> > > > to pick a suitable crt1.o for static PIE when -static-pie is used.
> > > >
> > > > If gcc.c can convert ... -static ... -pie and ... -pie ... -static ... to
> > > > -static-pic for GNU_USER_TARGET_STARTFILE_SPEC, it
> > > > should work.
> > > >
> > > > --
> > > > H.J.
> > >
> > > Great, that's how I've fixed it locally. Would you consider accepting
> > > a patch for this?
> >
> > I'd like to see it in GCC 8.  Please open a GCC bug and submit your
> > patch against it.
> >
> > Thanks.
> >
> > --
> > H.J.