Re: -data-disassemble segmetation fault

[Andrew Cagney <ac131313@redhat.com>]

> Hi,
> 
> I tried using the -data-disassemble command on the attached file.
> I ran this command,
> -data-disassemble -f basic.c -l 25 -n -1 -- 1
> and gdb segfaulted.
> 
> I am concerned that the MI code is being presented as an alternative 
> interface to GDB, but it is mainly untested when it comes to building 
> a practical application on top of it.   Either that, or I just found the
> needle in the haystack crash, since it was the first or second command I
> ran.

Given that a quick glance at GDBs testsuite reveals that it is trying 
all the following combinations:

111-data-disassemble -s $pc -e "$pc + 12" -- 0
222-data-disassemble  -f basics.c -l 32 -- 0
002-data-disassemble -f basics.c -l 21 -- 1
003-data-disassemble -s $pc -e "$pc+4" -- 1
123-data-disassemble -f foo -l abc -n 0 -- 0
321-data-disassemble -s foo -e bar -- 0
456-data-disassemble -s $pc -f basics.c -- 0
789-data-disassemble -f basics.c -l 32 -- 9
222-data-disassemble  -f basics.c -l 32 -n 20 -- 0
222-data-disassemble  -f basics.c -l 32 -n 0 -- 0
222-data-disassemble  -f basics.c -l 32 -n 50 -- 0
222-data-disassemble  -f basics.c -l 32 -n 20 -- 1
222-data-disassemble  -f basics.c -l 32 -n 0 -- 1
222-data-disassemble  -f basics.c -l 32 -n 50 -- 1
111-data-disassemble -s $pc -e "$pc + 12" -- 0
222-data-disassemble  -f basics.c -l 32 -- 0
002-data-disassemble -f basics.c -l 21 -- 1
003-data-disassemble -s $pc -e "$pc+4" -- 1
123-data-disassemble -f foo -l abc -n 0 -- 0
321-data-disassemble -s foo -e bar -- 0
456-data-disassemble -s $pc -f basics.c -- 0
789-data-disassemble -f basics.c -l 32 -- 9
222-data-disassemble  -f basics.c -l 32 -n 20 -- 0
222-data-disassemble  -f basics.c -l 32 -n 0 -- 0
222-data-disassemble  -f basics.c -l 32 -n 50 -- 0
222-data-disassemble  -f basics.c -l 32 -n 20 -- 1
222-data-disassemble  -f basics.c -l 32 -n 0 -- 1
222-data-disassemble  -f basics.c -l 32 -n 50 -- 1

I'd assume that you've tickled an edge case.

> Please let me know if I am doing anything wrong.
> 
> I have attached the file that reproduced the crash ( basic.c ), and I also
> attached a backtrace. I was running a gdb out of cvs, freshly updated
> tonight ( 07/29/2003 ).

Can you turn this into a bug report (transcript of what lead to the 
sigseg) and an addition gdb<PRNUM> to the testsuite.  That way it can be 
added to the repository.  Of course, if you've also got a patch.

Andrew