[gentoo-mips] hash-style trouble with gcc, binutils and glibc

[Jens Seidel <jensseidel@users.sf.net>]

Hi,

since the last system upgrade I always get floating point exceptions when I
start self compiled programs or during configure steps (once the gcc compiler
is tested). After some searching I found that ld --hash-style= option is the
reason. Some time ago a new "gnu" method was introduced to speed loading of
dynamic libraries up.

The problem I have is that glibc uses still the old sysv hash whereas
gcc (or/and ld) defaults to gnu. Using -Wl,--hash-style=sysv in CFLAGS,
CXXFLAGS and LDFLAGS improves the situation as I can now continue
compiling C (but no C++) programs. I rebuild gcc (4.1.2), glibc (2.3.6-r5)
and binutils (2.18-r1) but it did not helped.

I assumed that --hash_style=both is the new toolchain default and would put
both old hash and new gnu_hash into binaries and would allow me linking against
my glibc (which still uses old hash). But I was wrong:

$ mips-unknown-linux-gnu-gcc -Wl,--hash-style=sysv main.c
$ ./a.out
Hello world
$ mips-unknown-linux-gnu-gcc -Wl,--hash-style=both main.c
$ ./a.out
Floating point exception
$ mips-unknown-linux-gnu-gcc -Wl,--hash-style=gnu main.c
$ ./a.out
Floating point exception

With sysv I get:
$ readelf -a a.out | grep -i hash
  [ 5] .hash             HASH            004002ac 0002ac 000048 04   A  6   0  4   03     .interp .note.ABI-tag .reginfo .dynamic .hash .dynsym .dynstr .gnu.version .gnu.version_r .init .text .MIPS.stubs .fini .rodata .eh_frame
 0x00000004 (HASH)                       0x4002ac

and with gnu and both I get the same output:
$ cat  /tmp/readelf.both
  [ 5] .gnu.hash         GNU_HASH        004002ac 0002ac 00004c 04   A  6   0  4   03     .interp .note.ABI-tag .reginfo .dynamic .gnu.hash .dynsym .dynstr .gnu.version .gnu.version_r .init .text .MIPS.stubs .fini .rodata .eh_frame
 0x6ffffef5 (GNU_HASH)                   0x4002ac
     1: 00000000     0 FUNC    WEAK   DEFAULT [GNUHASH]   UND __gmon_start__
     2: 00000000     0 NOTYPE  WEAK   DEFAULT [GNUHASH]   UND _Jv_RegisterClasses
     3: 00400860   476 FUNC    GLOBAL DEFAULT [GNUHASH]   UND puts@GLIBC_2.0 (2)     5: 0040075c   128 FUNC    GLOBAL DEFAULT [GNUHASH]    11 __libc_csu_init
     7: 00400680    88 FUNC    GLOBAL DEFAULT [GNUHASH]    11 main
     8: 0040049c     0 FUNC    GLOBAL DEFAULT [GNUHASH]    10 _init
     9: 004006e0   124 FUNC    GLOBAL DEFAULT [GNUHASH]    11 __libc_csu_fini
    11: 00400880     0 FUNC    GLOBAL DEFAULT [GNUHASH]    13 _fini
    12: 00400850   308 FUNC    GLOBAL DEFAULT [GNUHASH]   UND __libc_start_main@GLIBC_2.0 (2)
    34: 004006e0   124 FUNC    GLOBAL DEFAULT [GNUHASH]    11 __libc_csu_fini
    37: 00000000     0 FUNC    WEAK   DEFAULT [GNUHASH]   UND __gmon_start__
    38: 00000000     0 NOTYPE  WEAK   DEFAULT [GNUHASH]   UND _Jv_RegisterClasses
    39: 00400880     0 FUNC    GLOBAL DEFAULT [GNUHASH]    13 _fini
    41: 00400850   308 FUNC    GLOBAL DEFAULT [GNUHASH]   UND __libc_start_main@@GLIBC_
    47: 0040075c   128 FUNC    GLOBAL DEFAULT [GNUHASH]    11 __libc_csu_init
    52: 00400860   476 FUNC    GLOBAL DEFAULT [GNUHASH]   UND puts@@GLIBC_2.0
    55: 00400680    88 FUNC    GLOBAL DEFAULT [GNUHASH]    11 main
    56: 0040049c     0 FUNC    GLOBAL DEFAULT [GNUHASH]    10 _init
Histogram for `.gnu.hash' bucket list length (total of 3 buckets):

This shows that --hash-style=both is identical to --hash-style=gnu and not
properly working on my system. Why?

I found also an article about hash style in the Gentoo Wiki and tried
rebuilding my toolchain with USE=hashstyle but this did not helped.

Any ideas? Is this a known error on Mips (o32 ABI)?

Jens
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