Subject: Relocation error with libstdbuf.so on Solaris SPARC with Studio compilation.

From: Rich Burridge <[email-masked]>
Date: Fri, 22 Jan 2016 02:28:26 -0800

Hi,

We've noticed an interesting problem recently with the version of stdbuf
(really libstdbuf.so) from coreutils version 8.24 on SPARC in Solaris 12.

If you do something like:

   $ stdbuf -oL echo

it generates:

ld.so.1: echo: fatal: relocation error: file /usr/lib/64/libstdbuf.so: 
symbol
program_name: referenced symbol not found
Killed

but that same command works just fine for stdbuf and libstdbuf.so from
8.24 in Solaris 12 on x86.

There's a similar problem for the 32-bit version as well. I'll use that
to describe what's going on.

I took the command we use to compile 32-bit libstdbuf.c on SPARC:

  $ /ws/on12-tools/SUNWspro/solarisstudio12.4/bin/cc  -I. 
-I/builds/richb/22510525-coreutils/components/coreutils/coreutils-8.24 
-I./lib  -Ilib 
-I/builds/richb/22510525-coreutils/components/coreutils/coreutils-8.24/lib 
-Isrc 
-I/builds/richb/22510525-coreutils/components/coreutils/coreutils-8.24/src 
-I/usr/include/gmp -D_REENTRANT -fPIC   -m32 -xO4 -xtarget=ultra2 
-xarch=sparcvis -xchip=ultra2 -Qoption cg -xregs=no%appl -W2,-xwrap_int  
-xmemalign=8s -mt  -c -o src/src_libstdbuf_so-libstdbuf.o `test -f 
'src/libstdbuf.c' || echo 
'/builds/richb/22510525-coreutils/components/coreutils/coreutils-8.24/'`src/libstdbuf.c

and adjusted that to use "-E" instead of "-c" and reran it to generate a
self-contained lsb.c source file (attached).

I then compiled/linked that on SPARC and x86 (using the commands that are
generated by our Userland build environment) and noticed the following 
differences:

x86:

   $ /ws/on12-tools/SUNWspro/solarisstudio12.4/bin/cc -fPIC -m32 -xO4 
'-xchip=pentium' '-xregs=no%frameptr' -mt -shared -o lsb.so lsb.c
"src/libstdbuf.c", line 97: warning: shift count negative or too big: << 63

   $ elfdump lsb.so | grep program_name
   $

SPARC:

   $ /ws/on12-tools/SUNWspro/solarisstudio12.4/bin/cc -fPIC -m32 -xO4 
'-xtarget=ultra2' '-xarch=sparcvis' '-xchip=ultra2' -Qoption cg 
'-xregs=no%appl' -W2,-xwrap_int '-xmemalign=8s' -mt -shared -o lsb.so lsb.c
"src/libstdbuf.c", line 97: warning: shift count negative or too big: << 63

   $ elfdump lsb.so | grep program_name
     [1]        0   0x4  OBJT GLOB  D    0 UNDEF program_name
    [42]        0   0x4  OBJT GLOB  D    0 UNDEF program_name
        2  [1]     program_name
     [1]  0x1177c     0  R_SPARC_GLOB_DAT    program_name
    [12]  R_SPARC_GLOB_DAT  0x1177c     0      0  .got program_name
   $

Now you can see from lsb.c that the code includes:

extern const char *program_name;

...

static inline void
emit_try_help (void)
{
   fprintf ( ( & __iob [ 2 ] ),  gettext ( "Try '%s --help' for more 
information.\n" ), program_name);
}

It looks like the Studio compiler for x86 is nicely optimizing the
emit_try_help() away as it's not being used, but the SPARC version of
the Studio compiler isn't, and is causing the problem.

(Note that this isn't a problem with GNU compiling/linking on Solaris 
for both
x86 and SPARC).

Now I can "fix" this by adding progname.o (where the program_name variable
is defined) to libstdbuf.so as it's being linked.

   $ /ws/on12-tools/SUNWspro/solarisstudio12.4/bin/cc -fPIC -m32 -xO4 
'-xarch=sparcvis' '-xchip=ultra2' '-xregs=no%appl' '-xtarget=ultra2' 
-Qoption cg -W2,-xwrap_int '-xmemalign=8s' -mt -shared -o mylsb.so 
build/sparcv7/lib/progname.o lsb.c
"src/libstdbuf.c", line 97: warning: shift count negative or too big: << 63

   $ elfdump mylsb.so | grep program_name
    [20]  0x11ae4   0x4  OBJT GLOB  D    0 .data program_name
    [26]   0x1010  0xf0  FUNC GLOB  D    0 .text set_program_name
    [63]  0x11ae4   0x4  OBJT GLOB  D    0 .data program_name
    [69]   0x1010  0xf0  FUNC GLOB  D    0 .text set_program_name
    [42]   0x1010  0xf0  FUNC GLOB  D    0 .text set_program_name
    [36]  0x11ae4   0x4  OBJT GLOB  D    0 .data program_name
           [20]    program_name
       26  [26]    set_program_name
     [2]  0x11a10     0  R_SPARC_GLOB_DAT    program_name
    [23]  R_SPARC_HI22       0x10d4     0      0  .text program_name
    [24]  R_SPARC_LO10       0x10d8     0      0  .text program_name
    [25]  R_SPARC_GLOB_DAT  0x11a10     0      0  .got program_name

but program_name really is an undefined variable here in this context, 
so I was
wondering if there was a better fix that was needed here.

Thanks in consideration.

PS: Going to bed now; back online in a few hours...