Re: pushl computed immediate address on 2.8.1

[hjl@lucon.org (H.J. Lu)]

> 
> 
> I was thinking this was a bug in the SCO x86 assembler becuase it worked
> under GAS for Linux.   However, after some prodding form the egcs folks 
> that really know PIC, I'm wondering if this is actually a construct that 
> GAS should produce an error for becuase GCC shouldn't emit it.
> 
> The problem is that 
> 
> 	pushl $.LC0@GOTOFF(%ebx)
> 
> seems to assemble just like
> 
> 	pushl $LC0
> 
> so it ends up generating an push of an absolute address once the 
> linker gets done with it.
> 
> Does this sound right at all?    Should GAS error on this?
> 
> 
> Here's a short "hello, world" in PIC to exercise the issue.
> 
> 
> Thanx,
> 
> RJL
> 
> 	.file	"test.c"
> 	.section	.rodata
> .LC0:
> 	.string	"Hello, World\n"
> 
> 	.text
> 	.align 4
> 	.globl main
> 	.type	 main,@function
> main:
> 	pushl %ebp
> 	movl %esp,%ebp
> 	pushl %ebx
> 	call .L2
> .L2:
> 	popl %ebx
> 	addl $_GLOBAL_OFFSET_TABLE_+[.-.L2],%ebx
> 
> // This is the aproach that works, and is what GCC should emit.
> // registers
> 	leal .LC0@GOTOFF(%ebx),%eax
> 	pushl %eax
> 	call printf@PLT
> 
> // This what GCC does emit, but seems to be nonsensical.
> // assembler.
> 	pushl $.LC0@GOTOFF(%ebx)
> 	call printf@PLT
> 

Which gcc are you using? How did you get gcc to emit that?
I only can get my gcc to generate

leal .LC0@GOTOFF(%ebx),%eax
pushl %eax
call printf@PLT

I tried egcs 971215, egcs 1.0.1 and gcc 2.8.0 971225. They
are all the same.

H.J.