[Bug bootstrap/50237] New: [4.7 regression] comparison failure caused by HAVE_INITFINI_ARRAY check

["ebotcazou at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50237

             Bug #: 50237
           Summary: [4.7 regression] comparison failure caused by
                    HAVE_INITFINI_ARRAY check
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: blocker
          Priority: P3
         Component: bootstrap
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: ebotcazou@gcc.gnu.org
              Host: x86_64-suse-linux
            Target: x86_64-suse-linux
             Build: x86_64-suse-linux


I have had a bootstrap comparison failure for days on x86-64/Linux:

libcpp/lex.o differs

It turns out that stage3 has

  6 .init_array   00000008  0000000000000000  0000000000000000  00003d20  2**3
                  CONTENTS, ALLOC, LOAD, RELOC, DATA

but stage2 has

  6 .ctors        00000008  0000000000000000  0000000000000000  00003d20  2**3
                  CONTENTS, ALLOC, LOAD, RELOC, DATA

That isn't surprising because HAVE_INITFINI_ARRAY isn't uniform:

eric@hermes:~/build/gcc/native> grep HAVE_INITFINI_ARRAY stage1-gcc/auto-host.h 
/* #undef HAVE_INITFINI_ARRAY */
eric@hermes:~/build/gcc/native> grep HAVE_INITFINI_ARRAY prev-gcc/auto-host.h
#define HAVE_INITFINI_ARRAY 1

i.e. despite http://gcc.gnu.org/ml/gcc-patches/2011-06/msg00659.html the check
is still applied to the host compiler, not to the target.  The base compiler is
the system compiler on OpenSuSE 11.0 and the check doesn't pass for it:

eric@hermes:~/build/gcc/native> gcc -o t t.c
eric@hermes:~/build/gcc/native> ./t
Aborted

The compiler is configured with

eric@hermes:~/build/gcc/native> gcc/xgcc -v
Using built-in specs.
COLLECT_GCC=gcc/xgcc
Target: x86_64-suse-linux
Configured with: /home/eric/svn/gcc/configure x86_64-suse-linux
--prefix=/home/eric/install/gcc
--with-as=/home/eric/build/binutils/native/gas/as-new
--with-ld=/home/eric/build/binutils/native/ld/ld-new
--enable-languages=c,c++,objc,obj-c++,java,fortran,ada
--enable-checking=yes,rtl --enable-__cxa_atexit --disable-nls
--disable-libmudflap
Thread model: posix
gcc version 4.7.0 20110830 (experimental) [trunk revision 178287] (GCC)


A workaround would be to get rid of the __attribute__((constructor)) in lex.c
but someone should sit down and write a correct HAVE_INITFINI_ARRAY check.