[gdb]howto specify breakpoints with gdb convenience variables

[gdb]howto specify breakpoints with gdb convenience variables

[Larry Evans]

My */gcc/.gdbinit contains lines like:

#cp_parser_template_parameter:./* ...we have a template type parameter.
break parser.c:9730
condition $bpnum expand_location(input_location).line>(99)
commands
call expand_location(token->location)
call cp_lexer_start_debugging(parser->lexer)
end

Now, there's several of these, and I wanted to use change:

   cp_lexer_print_token

to print the line and column numbers of the token.  Well,
of course this changed the breakpoint line numbers; so,
I was wondering if there was some way to set a convenience
variable:

http://ftp.sunsite.ualberta.ca/Documentation/Gnu/gdb-4.18/html_node/gdb_60.html#SEC60

so that the breakpoints could conveniently be adjusted
after changes to the source code.  IOW, something like:

   set $lje_bp_line_correction = 5
   set $lje_bp_line_next = (5238+$lje_bp_line_correction)
   break parser.c:$lje_bp_line_next

However, this just resulted in:

Breakpoint 3 at 0x58a5a6: file 
/home/evansl/download/gcc/4.4-20090630/build/../src/gcc/cp/parser.c, 
line 22148.
Breakpoint 4 at 0x0

IOW, it appears the line:

   break parser.c:$lje_bp_line_next

doesn't work.

How do I get it to work?

TIA.

-Larry

Re: [gdb]howto specify breakpoints with gdb convenience variables

[Larry Evans]

On 07/12/09 10:44, Larry Evans wrote:
[snip]
> I was wondering if there was some way to set a convenience
> variable:
[snip]
> so that the breakpoints could conveniently be adjusted
> after changes to the source code.  IOW, something like:
> 
>   set $lje_bp_line_correction = 5
>   set $lje_bp_line_next = (5238+$lje_bp_line_correction)
>   break parser.c:$lje_bp_line_next
[snip]

Based on:

   http://sourceware.org/ml/gdb/2008-02/msg00070.html

I guess there's no way to do that :(

Re: [gdb]howto specify breakpoints with gdb convenience variables

[Tom Tromey]

>>>>> "Larry" == Larry Evans <cppljevans@suddenlink.net> writes:

Larry> Based on:
Larry>   http://sourceware.org/ml/gdb/2008-02/msg00070.html
Larry> I guess there's no way to do that :(

If you use the cvs gdb you can do it using python.

In plain gdb you can do it by using set logging to set the output
file, writing the data to it in a source-able form (or using shell sed
or whatever to transform it), then sourcing the file.

Tom