RE: Wrong mapping pc to line numbers when listing coff

[Andrew Volkov <Andrew dot Volkov at transas dot com>]

Elena,

Sorry, but provide simple example (and backtrace) is not so easy. I'm
attached very elementary bzipped project for Hitachi 2623 (h8S/300) based
board (sorry for clumsy make file, it was generated automaticlly), gcc
v3.0.2 (with last Kazu Hirata's patch
http://prdownloads.sourceforge.net/h8300-hms/h8300-hms-gcc-3.0.2-1.patch),
binutils v 2.11.90 (I trying with older version of both - result the same).
For building, type 

make -f test.mak rebuild

So when debugging under gdb-5.0.92 (h8300-hms-gdb test.out) you could wrote:


(gdb) list main

And you will see next:

37      }
38
39
40      int main()
41      {
42       LED_ON();
43       CpuUnlock();
44
45       for(;;)
46       {

But, right list (as I understand)

40      int main()
41      {
42       LED_ON();
43       CpuUnlock();
44
45       for(;;)
46       {
47	   LED_TOGGLE();
48
49	   }
50	  }

I'm checking assembly listing with debug info and all, what insert gcc, was
correct. Object files I checked with nm and its output show all ok too. When
I tracing find_pc_sect_line, then "prev" setting on truely previous symbol
(end of function _low_level_init) and "item" pointed to "main". But when
returning, "best" contain information from "*prev" :(.

Andrey

P.S. This bug influence not only to list (this is not comfortable, but
tolerably), but on breakpoints and tracing, whats ugly :(.

> -----Original Message-----
> From: Elena Zannoni [mailto:ezannoni@cygnus.com]
> Sent: Friday, November 09, 2001 6:28 PM
> To: Andrew Volkov
> Cc: ezannoni@redhat.com; gdb@sources.redhat.com
> Subject: Re: Wrong mapping pc to line numbers when listing coff
> 
> 
> Andrew Volkov writes:
>  > Hi Elena,
>  > 
>  > As I understand (may be I wrong :), file gdb/symtab.c 
> belong to you. Well, I
>  > found next bug/incorrectness in find_pc_sect_line function:
>  >  When I build coff target from c++ files (with templates) 
> and debugging it,
>  > then find_pc_sect_line return wrong start line number. 
> It's because this
>  > function consider that symbol with lower pc then current 
> pc (argument of
>  > find_pc_sect_line) is belong to first line (or vice 
> versa), this is not
>  > always correct, especcially for functions. In functions 
> first line came
>  > after prologs, and hence, best.pc (and best.line) must be 
> greater then
>  > current pc. I could correct this incorrectness, but it 
> will be better, if
>  > you tell me your ideas about this situation.
>  > 
>  > Regards,
>  > Andrey
> 
> 
> Andrey,
> yes I am one of the maintainers for that file.
> 
> Could you provide an example where this situation occurs?
> Also a backtrace from find_pc_sect_line could be useful.
> 
> Have you verified that the debug information for your program 
> is correct?
> 
> 
> Thanks
> Elena
>

test.tar.bz2