bad compiler generated code? - firefox issues

[Sean McNeil]

On Thu, 2004-06-17 at 18:24, Sean McNeil wrote:
> On Tue, 2004-06-15 at 18:57, David O'Brien wrote:
> > On Tue, Jun 15, 2004 at 05:48:08PM -0700, Sean McNeil wrote:
> > > I'm recompiling firefox right now and I get a whole bunch of the
> > > following:
> > > 
> > > {standard input}:766: Warning: indirect jmp without `*'
> > > {standard input}:816: Warning: indirect jmp without `*'
> > ...
> > > this happens on quite a number of C++ source files.  Looks like the
> > > compiler is generating some bad assembly.
> > 
> > This is not a useful bug report.  Can you provide the preprocesed C file?
> > Or at least provide command line(s) invocation that produces this?
> 
> I took a look into this and it appears that the bad code generation of
> c++ is related to my issues with firefox.  Here is what I saw:
> 
> In xpcom/base/nsExceptionService.cpp it is generating thunks as
> 
> _ZThn8_N18nsExceptionService6AddRefEv:
> 	addq	$-8, %rdi
> 	jmp	_ZN18nsExceptionService6AddRefEv(%rip)
> 	.size	_ZThn8_N18nsExceptionService6AddRefEv, .-_ZThn8_N18nsExceptionService6AddRefEv
> 
> when they should be
> 
> _ZThn8_N18nsExceptionService6AddRefEv:
> 	addq	$-8, %rdi
> 	jmp	_ZN18nsExceptionService6AddRefEv
> 	.size	_ZThn8_N18nsExceptionService6AddRefEv, .-_ZThn8_N18nsExceptionService6AddRefEv
> 
> This has been fixed in the cvs version of gcc and involves the following patch:
> 
> *** contrib/gcc/config/i386/i386.c.orig Thu Jun 17 18:20:11 2004
> --- contrib/gcc/config/i386/i386.c      Thu Jun 17 18:10:55 2004
> *************** x86_output_mi_thunk (file, thunk, delta,
> *** 14607,14621 ****
>         output_asm_insn ("mov{l}\t{%0, %1|%1, %0}", xops);
>       }
> 
> !   xops[0] = DECL_RTL (function);
>     if (TARGET_64BIT)
>       {
>         if (!flag_pic || (*targetm.binds_local_p) (function))
>         output_asm_insn ("jmp\t%P0", xops);
>         else
>         {
> !         tmp = XEXP (xops[0], 0);
> !         tmp = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, tmp), UNSPEC_GOTPCREL);
>           tmp = gen_rtx_CONST (Pmode, tmp);
>           tmp = gen_rtx_MEM (QImode, tmp);
>           xops[0] = tmp;
> --- 14607,14620 ----
>         output_asm_insn ("mov{l}\t{%0, %1|%1, %0}", xops);
>       }
> 
> !   xops[0] = XEXP (DECL_RTL (function), 0);
>     if (TARGET_64BIT)
>       {
>         if (!flag_pic || (*targetm.binds_local_p) (function))
>         output_asm_insn ("jmp\t%P0", xops);
>         else
>         {
> !         tmp = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, xops[0]), UNSPEC_GOTPCREL);
>           tmp = gen_rtx_CONST (Pmode, tmp);
>           tmp = gen_rtx_MEM (QImode, tmp);
>           xops[0] = tmp;
> 
> 
> I am rebuilding firefox with this patch and will report back if firefox works.

I had to do a complete rebuild:  portupgrade -fR firefox-0.9_1

Now firefox works!!!

There must have been other libraries that firefox depended on that were
built with the bad compiler.

Sean