Re: [issue1525] boehm-gc problems

[Jordan Gordeev <jgordeev@xxxxxx>]

There's a difference between DragonFly's ld and FreeBSD's ld.
Let's take the following program:
extern void *vodka;

void *
f(void)
{
       return vodka;
}

We compile it into a shared library:
%cc -c -o vodka.o vodka.c
%ld -Bshareable -o libvodka.so vodka.o

Then we do:
%objdump -t libvodka.so

Doing the above steps on DragonFly produces:

libvodka.so:     file format elf32-i386

SYMBOL TABLE:
00000094 l    d  .hash  00000000 .hash
000000c4 l    d  .dynsym        00000000 .dynsym
00000134 l    d  .dynstr        00000000 .dynstr
00000158 l    d  .rel.dyn       00000000 .rel.dyn
00000160 l    d  .text  00000000 .text
0000116c l    d  .dynamic       00000000 .dynamic
000011e4 l    d  .got.plt       00000000 .got.plt
00000000 l    d  .comment       00000000 .comment
00000000 l    d  *ABS*  00000000 .shstrtab
00000000 l    d  *ABS*  00000000 .symtab
00000000 l    d  *ABS*  00000000 .strtab
00000000 l    df *ABS*  00000000 vodka.c
0000116c l     O *ABS*  00000000 .hidden _DYNAMIC
000011e4 l     O *ABS*  00000000 .hidden _GLOBAL_OFFSET_TABLE_
00000160 g     F .text  0000000a f
00000000         *UND*  00000000 vodka
000011f0 g       *ABS*  00000000 __bss_start
000011f0 g       *ABS*  00000000 _edata
000011f0 g       *ABS*  00000000 _end

Doing the steps on FreeBSD produces:

libvodka.so:     file format elf32-i386-freebsd

SYMBOL TABLE:
00000094 l    d  .hash  00000000
00000128 l    d  .dynsym        00000000
00000248 l    d  .dynstr        00000000
00000288 l    d  .rel.dyn       00000000
00000290 l    d  .text  00000000
0000129c l    d  .data  00000000
0000129c l    d  .dynamic       00000000
00001314 l    d  .got   00000000
00001320 l    d  .bss   00000000
00000000 l    d  .comment       00000000
00000000 l    d  *ABS*  00000000
00000000 l    d  *ABS*  00000000
00000000 l    d  *ABS*  00000000
00000000 l    df *ABS*  00000000 vodka.c
0000129c g     O *ABS*  00000000 _DYNAMIC
00000290 g     F .text  0000000a f
00000000         *UND*  00000000 vodka
00001320 g       *ABS*  00000000 __bss_start
00001320 g       *ABS*  00000000 _edata
00001314 g     O *ABS*  00000000 _GLOBAL_OFFSET_TABLE_
00001320 g       *ABS*  00000000 _end

Please, note that '_DYNAMIC' is a local symbol on DragonFly and a global 
one on FreeBSD.