Re: [arch-general] Issue linking 32-bit GAS assembly

17 Oct 2018

      On Wed, Oct 17, 2018 at 11:07:02PM +0200, Maarten de Vries via arch-general wrote:
...
Why not let gcc take care of what compiler/assembler and linker to invoke
with which precise flags:
$ gcc -m32 -o foo filename.s
$ ./foo # great success!
It will probably link to libc without you even asking for it. And if that
works and you really want to know what linker flags you need, you can add -v
to make gcc spam you about it.
GCC will handle some files, but not others.  In this case, I get
garbage output then a segfault/core dump.

Using -nostdlib and -static also fail to build, but I have had success
with just using 

I would, however, like to know how to use as/ld on Arch, as it is my
main OS.
...
-- Maarten
(Sent off-list by accident before, sending to the list now.)
On 10/17/18 9:36 PM, Dutch Ingraham wrote:
...
Hi all:
I'm having a problem linking 32-bit GAS assembly code that references external
C libraries on an up-to-date 64-bit Arch installation.
I have enabled the 32-bit repositories and installed the multilib-devel group
and lib32-glibc. I have updated the library cache with ldconfig and rebooted.
The command to assemble is: .  Assembly
succeeds.
However, when linking using the command

the command fails with:
  ld: skipping incompatible /usr/lib/libc.so when searching for -lc
  ld: skipping incompatible /usr/lib/libc.a when searching for -lc
  ld: cannot find -lc
Note this linker command (or a hierarchy-appropriate one) seems standard, and
succeeds on a 64-bit Debian OS.
There is a fairly recent Forum question (but pre-dating the discontinuance of
i686 support) regarding the same issue at
https://bbs.archlinux.org/viewtopic.php?id=229235 which indicates the command
should be:

This command succeeds, insofar as the linker returns an exit code of 0. However,
running the program (and all other similar programs) fails with "Illegal
instruction (core dumped)." Assembling with debugging symbols and running a
backtrace didn't enlighten me.
Note that changing /lib/ld-linux to /usr/lib32/ld-linux in the command immediately
above produces the same result, as confirmed by the output of 
Anyone see something I've missed of have any suggestions?  Thanks.
-----------
Here is some simple code to test with:
# paramtest2.s - Listing system environment variables
.section .data
output:
    .asciz "%s\n"
.section .text
.globl _start
_start:
    movl %esp, %ebp
    addl $12, %ebp
loop1:
    cmpl $0, (%ebp)
    je endit
    pushl (%ebp)
    pushl $output
    call printf
    addl $12, %esp
    addl $4, %ebp
    loop loop1
endit:
    pushl $0
    call exit