Re: gcc HEAD bad stabs (?)

[Daniel Jacobowitz <drow@mvista.com>]

On Fri, Sep 12, 2003 at 04:11:15AM -0400, Michael Elizabeth Chastain wrote:
> I think gcc HEAD is emitting bad stabs again,
> and need some confirmation before I can file a bug report.
> 
> The questionable stabs happen when 'main' calls 'factorial',
> but there is no prototype for 'factorial' yet.  Here are all
> the stabs after the boilerplate stabs.  The full source code
> and assembly code are at the end of the message.
> 
> 	# some stabs for factorial
> 	.stabs	"factorial:F(0,3)",36,0,13,factorial
> 	.stabs	"value:p(0,3)",160,0,12,8
> 	.stabs	"value:r(0,3)",64,0,12,3
> 	.stabs	"",36,0,0,.Lscope0-factorial
> 	# some stabs for main
> 	.stabs	"main:F(0,3)",36,0,6,main
> 	.stabs	"argc:p(0,3)",160,0,5,8
> 	.stabs	"argv:p(0,21)=*(3,36)",160,0,5,12
> 	.stabs	"envp:p(0,21)",160,0,5,16
> 	.stabs	"/usr/include/stdlib.h",132,0,0,.Ltext1
> 	.stabs	"z0.c",132,0,0,.Ltext2
> 	# stray stab for factorial!!
> 	.stabs	"factorial:F(0,3)",36,0,13,factorial
> 	# end of main
> 	.stabs	"",36,0,0,.Lscope1-main
> 	.stabs "",100,0,0,.Letext
> 
> Look at that stray stab for factorial, which occurs just
> before the stab for .Lscope1-main!
> 
> This causes a subtle problem in gdb.  gdb gets a bogus endaddr
> for the block with main in it, so find_function_start_sal fails
> to adjust for the prologue properly, so the breakpoint at the
> beginning of an instruction happens too early.  The bad block
> probably causes more problems, too.

I agree that this is a bug.  Factorial is not inside of main, so stabs
with its address shouldn't be either.



-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer