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Re: GDB 5.2/5.3 breakpoint bug
On Wed, Jan 08, 2003 at 02:45:23PM -0800, Ching Lai wrote:
> Hi Daniel,
>
> > > Comment out the line 2753 in gdb 5.21 and 2777 in gdb 5.3 and build
> them
> > on
> > > solaris seems to work OK with two test cases.
> > >
> > > Now the question is to figure out why this line is added in gdb 5.21
> and
> > > gdb 5.3?
> >
> > The line is supposed to be there; it's so we know what is and isn't
> > inside a function. You need to explain better why it's causing a
> > problem in find_pc_sect_line.
>
> The problem is the linetable in different symbol tables have the
> same pc address in my testcase. One has valid number and the other one
> with line number as 0 (which is added by the extra record_line()).
>
> In gdb 5.2.1 release of find_pc_set_line in symtab.c file.
>
> 1788 /* Is this file's best line closer than the best in the other
> files?
> 1789 If so, record this file, and its best line, as best so far.
> */
> 1790
> 1791 if (prev && (!best || prev->pc > best->pc))
> 1792 {
> 1793 best = prev;
> 1794 best_symtab = s;
> 1795
> 1796 /* Discard BEST_END if it's before the PC of the current
> BEST. */
> 1797 if (best_end <= best->pc)
> 1798 best_end = 0;
> 1799 }
>
> Since the line 1791 prev->pc with valid line number is not greater than
> best->pc
> which has 0 as line number, so it did not pick up the correct symbol file.
>
> If the record_line is need in gdb 5.2.1 and gdb 5.3, then the line 1791
> might
> need an extra condition to void picking up the wrong symbol table which has
> line
> number as 0 as added by record_line().
>
> 1791 if (prev && (!best || prev->pc > best->pc) && (prev->line != 0))
>
>
> Here are the debugging section of my observation.
Thanks for the extra detail. I see what's going on now; I believe this
patch should also avoid the problem. Does it?
--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer
2002-03-08 Daniel Jacobowitz <drow@mvista.com>
* symtab.c (find_pc_sect_line): Don't consider end-of-function
lines.
Index: symtab.c
===================================================================
RCS file: /cvs/src/src/gdb/symtab.c,v
retrieving revision 1.84
diff -u -p -r1.84 symtab.c
--- symtab.c 2 Jan 2003 14:27:26 -0000 1.84
+++ symtab.c 9 Jan 2003 03:38:36 -0000
@@ -2012,9 +2012,11 @@ find_pc_sect_line (CORE_ADDR pc, struct
the first line, prev will not be set. */
/* Is this file's best line closer than the best in the other files?
- If so, record this file, and its best line, as best so far. */
+ If so, record this file, and its best line, as best so far. Don't
+ save prev if it represents the end of a function (i.e. line number
+ 0) instead of a real line. */
- if (prev && (!best || prev->pc > best->pc))
+ if (prev && prev->line && (!best || prev->pc > best->pc))
{
best = prev;
best_symtab = s;