And now... for something different

[samiam95124]

And now... for something different

1: program test(output);
2:
3: begin
4:
5:    writeln('hello, world')
6:
7: end.

samiam@samiam-h-pc-2:~/projects/pascal/pascal-p6$ gdb test
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Reading symbols from test...
(gdb) b test.pas:5
Breakpoint 1 at 0x438203: file test.pas, line 5.
(gdb) r
Starting program: /home/samiam/projects/pascal/pascal-p6/test 
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 1, test () at test.pas:5
5	    writeln('hello, world')
(gdb) n
hello, world
7	end.
(gdb) 

Yes, that is source level debug with gdb. No more digging through .s files to figure out source to assembly correspondence. It does not do things like print variables or locals, or do backtraces, etc. This would take a full intermediate to dwarf format converter[1] (dwarf is the gdb debugging format). However, its a nice step up.

Kudos to gdb. This was a fairly simple addition of the line numbers and filenames, and from there gdb does all the work of cataloging the source files and source lines to assembly line equivalences.

Enjoy! Things will only get better.

Wait what about...

Of course, I should do a plug for the pint intermediate debug mode of Pascal-P6. This does source, backtrace, all variables, and more more more. I recommend checking it out.

[1] Yea, it will happen. Its not that easy.

[samiam95124]

Working with symbols

gdb understands now what .pas source files are assocated with what assembly files. Thus things like:

(gdb) b module.pas:module.thisroutine

work fine. You have to spell out the complete qualident.

Things what don't work

The n command in gdb (step over routines) does not appear to work. To get that behavior, instead set a breakpoint after the routine. Note that gdb will understand line numbers as in "b line" as being in the presently active file, so you don't have to spell out the complete module.