[PATCHv2] Handle not explicitly zero terminated strings in merge sections

[Rainer Orth]

Hi Eric,

>> Which version exactly (pkg list entire) of Solaris 11 are you running?
>> I'm using gas 2.31 and /bin/ld on Solaris 11.4 resp. 11.5 Beta, where
>> Bernd's patch in PR bootstrap/87551 fixed the remaining regressions.
>
> Solaris 11.3 with Gas 2.30.

I could now reproduce the regressions on Solaris 11.3 SRU 35.6 (the
latest and last 11.3 update), e.g.

+FAIL: gfortran.dg/allocatable_function_5.f90   -O1  execution test


Program received signal SIGBUS: Access to an undefined portion of a memory object.

Backtrace for this error:

Thread 2 received signal SIGSEGV, Segmentation fault.
[Switching to Thread 1 (LWP 1)]
0x00010fe0 in foo (_carg=12, carg=..., .__result=0x215d4 <slen.0>, 
    __result=<optimized out>)
    at /vol/gcc/src/hg/trunk/local/gcc/testsuite/gfortran.dg/allocatable_function_5.f90:41
41          res = carg(1:3)
(gdb) where
#0  0x00010fe0 in foo (_carg=12, carg=..., .__result=0x215d4 <slen.0>, 
    __result=<optimized out>)
    at /vol/gcc/src/hg/trunk/local/gcc/testsuite/gfortran.dg/allocatable_function_5.f90:41
#1  MAIN__ ()
    at /vol/gcc/src/hg/trunk/local/gcc/testsuite/gfortran.dg/allocatable_function_5.f90:22

1: x/i $pc
=> 0x10fe0 <MAIN__+24>: lduh  [ %g1 + 0x3a9 ], %g1
(gdb) p/x $g1
$1 = 0x10800

(gdb) x/7i MAIN__
   0x10fc8 <MAIN__>:    save  %sp, -104, %sp
   0x10fcc <MAIN__+4>:  call  0x213c4 <malloc@got.plt>
   0x10fd0 <MAIN__+8>:  mov  3, %o0
   0x10fd4 <MAIN__+12>: mov  %o0, %i5
   0x10fd8 <MAIN__+16>: sethi  %hi(0x10800), %g1
   0x10fdc <MAIN__+20>: or  %g1, 0x3a9, %g2     ! 0x10ba9
=> 0x10fe0 <MAIN__+24>: lduh  [ %g1 + 0x3a9 ], %g1

(gdb) x/s 0x10800+0x3a9
0x10ba9:        'foo calling \000'

Looking at the .rodata.str1.4 section, I see

$ objdump -s -j .rodata.str1.8 allocatable_function_5.exe

allocatable_function_5.exe:     file format elf32-sparc-sol2

Contents of section .rodata.str1.8:
 10ba8 6d666f6f 2063616c 6c696e67 20000000  mfoo calling ...
 10bb8 666f6f00 00000000 6c687300 00000000  foo.....lhs.....

This string table compression can be disabled with ld -z nocomprstrtab:

       -z nocompstrtab

           Disables the compression of ELF string  tables,  and  comment  sec-
           tions. By default, string compression is applied to SHT_STRTAB sec-
           tions, to SHT_PROGBITS  sections  that  have  their  SHF_MERGE  and
           SHF_STRINGS section flags set, and to comment sections.

This isn't necessary on Solaris 11.4, and Solaris 11.3/x86 isn't
affected as well.  I'm still determining what the best course of action
is: disable string merging support before Solaris 11.4 or enable the
workaround above instead.

sparc-sun-solaris2.11 and i386-pc-solaris2.11 bootstraps with
LD_OPTIONS='-z nocompstrtab' are currently running to check if this
fixes all regressions.

	Rainer

-- 
-----------------------------------------------------------------------------
Rainer Orth, Center for Biotechnology, Bielefeld University