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

Dutch Ingraham stoa at gmx.us
Wed Oct 17 19:36:37 UTC 2018


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: <as --32 -o filename.o filename.s>.  Assembly
succeeds.

However, when linking using the command
<ld -melf_i386 --dynamic-linker /lib32/ld-linux.so.2 -lc -o filename filename.o>

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:

<ld -melf_i386 -shared -L /usr/lib32 -dynamic-linker /lib/ld-linux.so.2 -o \
filename filename.o -lc>

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 <ldconfig -p>

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


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