[Bug target/59842] New: `__x86.get_pc_thunk.bx' referenced in section `.text': defined in discarded section…

[tg at mirbsd dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59842

            Bug ID: 59842
           Summary: `__x86.get_pc_thunk.bx' referenced in section `.text':
                    defined in discarded section…
           Product: gcc
           Version: 4.8.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tg at mirbsd dot org

Created attachment 31855
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31855&action=edit
test runner

Hi *,

I originally filed this as Debian #735564 but a user informed me they are also
seeing this on other GNU/Linux distributions, and with GCC 4.7.1 on Slackware.

Since a while, I’m getting errors like these:

`__x86.get_pc_thunk.bx' referenced in section `.text' of x3.o: defined in
discarded section `.text.__x86.get_pc_thunk.bx[__x86.get_pc_thunk.bx]' of x3.o

I used to be able to avoid them (although, back then, the symbol
was named “__i686.get_pc_thunk.bx”) by adding -march=i486, but
this no longer helps.

Screen log (the files x.sh, x.i and x.sym are attached):

tglase@tglase:~ $ mksh x.sh
`__x86.get_pc_thunk.bx' referenced in section `.text' of x3.o: defined in
discarded section `.text.__x86.get_pc_thunk.bx[__x86.get_pc_thunk.bx]' of x3.o
`__x86.get_pc_thunk.bx' referenced in section `.text' of x3.o: defined in
discarded section `.text.__x86.get_pc_thunk.bx[__x86.get_pc_thunk.bx]' of x3.o
`__x86.get_pc_thunk.bx' referenced in section `.text' of x3.o: defined in
discarded section `.text.__x86.get_pc_thunk.bx[__x86.get_pc_thunk.bx]' of x3.o
`__x86.get_pc_thunk.bx' referenced in section `.text' of x3.o: defined in
discarded section `.text.__x86.get_pc_thunk.bx[__x86.get_pc_thunk.bx]' of x3.o
`__x86.get_pc_thunk.bx' referenced in section `.text' of x3.o: defined in
discarded section `.text.__x86.get_pc_thunk.bx[__x86.get_pc_thunk.bx]' of x3.o
`__x86.get_pc_thunk.bx' referenced in section `.text' of x3.o: defined in
discarded section `.text.__x86.get_pc_thunk.bx[__x86.get_pc_thunk.bx]' of x3.o
`__x86.get_pc_thunk.bx' referenced in section `.text' of x3.o: defined in
discarded section `.text.__x86.get_pc_thunk.bx[__x86.get_pc_thunk.bx]' of x3.o
`__x86.get_pc_thunk.bx' referenced in section `.text' of x3.o: defined in
discarded section `.text.__x86.get_pc_thunk.bx[__x86.get_pc_thunk.bx]' of x3.o
`__x86.get_pc_thunk.bx' referenced in section `.text' of x3.o: defined in
discarded section `.text.__x86.get_pc_thunk.bx[__x86.get_pc_thunk.bx]' of x3.o
`__x86.get_pc_thunk.bx' referenced in section `.text' of x3.o: defined in
discarded section `.text.__x86.get_pc_thunk.bx[__x86.get_pc_thunk.bx]' of x3.o
`__x86.get_pc_thunk.bx' referenced in section `.text' of x3.o: defined in
discarded section `.text.__x86.get_pc_thunk.bx[__x86.get_pc_thunk.bx]' of x3.o
collect2: error: ld returned 1 exit status

IMHO, GCC may not mark symbols as discardable that it uses by itself. Adding
this to the symbol file is no solution either, as this becomes highly platform-
and compiler-dependent.