Re: [patch] Fix to processing end of function stab in dbxread.c

[Daniel Jacobowitz <drow at mvista dot com>]

On Wed, Jul 10, 2002 at 07:08:16PM -0700, Jim Ingham wrote:
> Index: dbxread.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/dbxread.c,v
> retrieving revision 1.33
> diff -c -w -r1.33 dbxread.c
> *** dbxread.c   10 May 2002 07:32:50 -0000      1.33
> --- dbxread.c   11 Jul 2002 01:58:29 -0000
> ***************
> Hi, all...
> 
> Fred added an extra record_line call which closes off the last SLINE in 
> a function when we come across the end of function N_FUN stab.  This 
> was a good thing, but unfortunately, he used function_start_offset, 
> which on most systems is just the offset to the TEXT section (the 
> exception being Solaris, where is actually is the real function start). 
>  He really meant to use last_function_start, which is the real address 
> of the last N_FUN stab seen.
> 
> I also fixed the comment before sline_found_in_function to accord with 
> its current usage, since the old comment is wrong.  We set 
> sline_found_in_function = 0 at the same time we set 
> last_function_start, but then we set it to 1 when we see the FIRST 
> SLINE in a function, but last_function_start is still good after that.  
> And nobody ever checks it to see if they should use last_function_start 
> or not...

Well, the archeology is hardly correct.  I added both
last_function_start and sline_found_in_function recently;
last_function_start was because I couldn't convince myself that I could
trust the other.  Note that in the normal N_SLINE handling, we use
function_start_offset and not last_function_start.  So if your change
was really correct then all the N_SLINEs for your function would be in
the wrong places too.

Could you please explain what problem you're trying to fix, and support
it with some stabs dumps?

> 
> *** 2761,2768 ****
>     static CORE_ADDR last_function_start;
> 
>     /* If this is nonzero, we've seen an N_SLINE since the start of the 
> current
> !      function.  Initialized to nonzero to assure that 
> last_function_start
> !      is never used uninitialized.  */
>     static int sline_found_in_function = 1;
> 
>     /* If this is nonzero, we've seen a non-gcc N_OPT symbol for this 
> source
> --- 2761,2768 ----
>     static CORE_ADDR last_function_start;
> 
>     /* If this is nonzero, we've seen an N_SLINE since the start of the 
> current
> !      function.  We use this to tell us to move the first sline to the 
> beginning
> !      of the function regardless of what its given value is. */
>     static int sline_found_in_function = 1;
> 
>     /* If this is nonzero, we've seen a non-gcc N_OPT symbol for this 
> source
> ***************
> *** 2799,2805 ****
>         {
>           /* This N_FUN marks the end of a function.  This closes off 
> the
>              current block.  */
> !         record_line (current_subfile, 0, function_start_offset + 
> valu);
>           within_function = 0;
>           new = pop_context ();
> 
> --- 2799,2805 ----
>         {
>           /* This N_FUN marks the end of a function.  This closes off 
> the
>              current block.  */
> !         record_line (current_subfile, 0, last_function_start + valu);
>           within_function = 0;
>           new = pop_context ();
> 
> Jim
> --
> Jim Ingham                                   jingham@apple.com
> Developer Tools - gdb
> Apple Computer
> 
> 

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer