Relocatable linking on x86-64 for i386

[Oleg Goldshmidt]

On Tue, Apr 5, 2011 at 11:27 AM, Valery Reznic <valery_reznic at yahoo.com>wrote:

>
> Create programs using gcc -m32 is fine.
> But I use ld command not to create the program, but to create object file
>
> While both
> ld -m elf_i386 file1.o file2.o -o output.o
> and
> gcc -m32 file1.o file2.o -o output.o
>
> create EXECUTABLE file (despite .o extension)
>

> I use
> ld -r file1.o file2.o -o output.o # Note -r
>
> that create "partially linked object file"
>

AFAIK, you can do everything you can do with ld via a "compiler driver". You
only need to make sure that a) you pass the right options to the linker
(using -Wl) and b) gcc does not attempt to do too much (e.g., pass default
startfiles and standard libraries to ld - it may fail if you do it not for
the actual architecture as you attempt to do). E.g.,

$ cat > file1.c
static int foo = 1;
$ cat > file2.c
static int bar = 2;
$ gcc -m32 -nostartfiles -nostdlib -Wl,--relocatable file1.c file2.c -o
file.o
$ file file.o
file.o: ELF 32-bit LSB relocatable, Intel 80386, version 1 (SYSV), not
stripped

This _should_ be equivalent to what you are doing, the only arguable
advantage is that gcc compiles and links in one go.

Note that _maybe_ (I have not tested it) gcc can do what you want in yet
another way - you can combine several compilation units into one object at
compile time using the -combine option (only works for C code!):

$ gcc -m32 -c -combine file1.c file2.c -o file.o
$ file file.o
file.o: ELF 32-bit LSB relocatable, Intel 80386, version 1 (SYSV), not
stripped

-- 
Oleg Goldshmidt | pub at goldshmidt.org
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