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use of ifndef inhibit_libc to disable the contents linux-unwind.h for targets with MD_UNWIND_SUPPORT
- From: "Stephen M. Kenton" <skenton at ou dot edu>
- To: gcc at gcc dot gnu dot org
- Date: Mon, 27 Aug 2007 15:29:23 -0500
- Subject: use of ifndef inhibit_libc to disable the contents linux-unwind.h for targets with MD_UNWIND_SUPPORT
During the recent discussion about cross compilers I was told "bugs
happen", so I went hunting.
I have been digging into why building a cross compiler dies in different
ways for different targets.
As seen below, the Linux targets which use glibc define
MD_UNWIND_SUPPORT and have
a customized linux-unwind.h file. However, mips and i386 start and end
those files with
#ifndef inhibit_libc .... #endif statements which disable the entire
contents of the file if inhibit_libc is set.
Those are the only two such targets I can successfully build with
inhibit_libc without the use of enable-sjlj-exceptions.
Is there some reason that every instance of linux-unwind.h should not
start and end with those same
#ifndef inhibit_libc ... #endif statements? Or, alternatively, should
setting of inhibit_libc force
a #undef MD_UNWIND_SUPPORT at some suitably central place rather than
doing things the
way that mips and i386 currently handle it?
Steve Kenton
[adminrig@454analyze gcc-4.2.1-stock]$ grep -r MD_UNWIND_SUPPORT
gcc/config/*
gcc/config/alpha/gnu.h:#undef MD_UNWIND_SUPPORT
gcc/config/alpha/linux.h:#define MD_UNWIND_SUPPORT
"config/alpha/linux-unwind.h"
gcc/config/alpha/vms.h:#define MD_UNWIND_SUPPORT "config/alpha/vms-unwind.h"
gcc/config/i386/gnu.h:#undef MD_UNWIND_SUPPORT
gcc/config/i386/linux64.h:#define MD_UNWIND_SUPPORT
"config/i386/linux-unwind.h"
gcc/config/i386/linux.h:#define MD_UNWIND_SUPPORT
"config/i386/linux-unwind.h"
gcc/config/ia64/linux.h:#define MD_UNWIND_SUPPORT
"config/ia64/linux-unwind.h"
gcc/config/ia64/unwind-ia64.c:#ifdef MD_UNWIND_SUPPORT
gcc/config/ia64/unwind-ia64.c:#include MD_UNWIND_SUPPORT
gcc/config/mips/linux.h:#define MD_UNWIND_SUPPORT
"config/mips/linux-unwind.h"
gcc/config/pa/pa32-linux.h:#define MD_UNWIND_SUPPORT
"config/pa/linux-unwind.h"
gcc/config/pa/pa-hpux.h:#define MD_UNWIND_SUPPORT "config/pa/hpux-unwind.h"
gcc/config/rs6000/linux64.h:#define MD_UNWIND_SUPPORT
"config/rs6000/linux-unwind.h"
gcc/config/rs6000/linux.h:#define MD_UNWIND_SUPPORT
"config/rs6000/linux-unwind.h"
gcc/config/rs6000/darwin.h:#define MD_UNWIND_SUPPORT
"config/rs6000/darwin-unwind.h"
gcc/config/s390/tpf.h:#define MD_UNWIND_SUPPORT "config/s390/tpf-unwind.h"
gcc/config/s390/linux.h:#define MD_UNWIND_SUPPORT
"config/s390/linux-unwind.h"
gcc/config/sh/linux.h:#define MD_UNWIND_SUPPORT "config/sh/linux-unwind.h"
gcc/config/sparc/linux64.h:#define MD_UNWIND_SUPPORT
"config/sparc/linux-unwind.h"
gcc/config/sparc/linux.h:#define MD_UNWIND_SUPPORT
"config/sparc/linux-unwind.h"
[adminrig@454analyze gcc-4.2.1-stock]$ find gcc/config -name linux-unwind.h
gcc/config/sparc/linux-unwind.h
gcc/config/mips/linux-unwind.h
gcc/config/i386/linux-unwind.h
gcc/config/pa/linux-unwind.h
gcc/config/ia64/linux-unwind.h
gcc/config/sh/linux-unwind.h
gcc/config/s390/linux-unwind.h
gcc/config/rs6000/linux-unwind.h
gcc/config/alpha/linux-unwind.h
[adminrig@454analyze gcc-4.2.1-stock]$ grep inhibit_libc `find
gcc/config -name linux-unwind.h`
gcc/config/mips/linux-unwind.h:#ifndef inhibit_libc
gcc/config/i386/linux-unwind.h: Don't use this at all if inhibit_libc
is used. */
gcc/config/i386/linux-unwind.h:#ifndef inhibit_libc
gcc/config/i386/linux-unwind.h:#endif /* ifdef inhibit_libc */
[adminrig@454analyze gcc-4.2.1-stock]$