[Bug ld/6478] New: stab warnings cause linker errors

[vincent dot riviere at freesbee dot fr]

This problems occurs on targets using an a.out format by default, while having
support for ELF format. Such targets include i386-pc-netbsdaout and 
m68k-netbsdaout.

Basically, in certain conditions, a "stab warning" in an object file cause ld to
discard all the symbols defined in that object.

When there is no stab warning, the testcases described here works fine.

$ cat a.s
        .extern _f
        jmp     _f

$ cat b.s
        .stabs "a linker warning",30,0,0,0
        .stabs "_f",1,0,0,0
        .globl _f
_f:     ret

$ as a.s -o a.o # file format a.out-i386-netbsd
$ as b.s -o b.o # file format a.out-i386-netbsd
$ ld a.o b.o -o ab # file format a.out-i386-netbsd
a.o:a.o:(.text+0x1): warning: a linker warning

We can see here that everything uses the a.out file format, and everything works
as expected.

The problem occurs if a.o is converted to ELF.

$ objcopy a.o a-elf.o -O elf32-i386
BFD: a-elf.o: warning: allocated section `.text' not in segment

$ ld a-elf.o b.o -o ab
a-elf.o:(.text+0x1): warning: a linker warning
a-elf.o:(.text+0x1): undefined reference to `_f'

The link fails because the symbol _f is not found, however it is still in the
b.o file.

$ binutils-2.18-netbsd.obj/binutils/objdump -t b.o

b.o:     file format a.out-i386-netbsd

SYMBOL TABLE:
00000000    W d  *ABS* 0000 00 1e a linker warning
00000000 g       *ABS* 0000 00 03 _f
00000000 g       .text 0000 00 05 _f

Further strangeness comes if we convert a.o into ELF, too.

$ objcopy a.o a-elf.o -O elf32-i386
BFD: a-elf.o: warning: allocated section `.text' not in segment

$ ld a-elf.o b-elf.o -o ab
b-elf.o: In function `_f':
(.text+0x0): multiple definition of `_f'

-- 
           Summary: stab warnings cause linker errors
           Product: binutils
           Version: 2.18
            Status: NEW
          Severity: normal
          Priority: P2
         Component: ld
        AssignedTo: unassigned at sources dot redhat dot com
        ReportedBy: vincent dot riviere at freesbee dot fr
                CC: bug-binutils at gnu dot org
GCC target triplet: i386-pc-netbsdaout


http://sourceware.org/bugzilla/show_bug.cgi?id=6478

------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.