[Bug breakpoints/12958] New: How to set a breakpoint at the exit of a function?

[Bug breakpoints/12958] New: How to set a breakpoint at the exit of a function?

[wuchengping at h3c dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=12958

           Summary: How to set a breakpoint at the exit of a function?
           Product: gdb
           Version: 7.2
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: breakpoints
        AssignedTo: unassigned@sourceware.org
        ReportedBy: wuchengping@h3c.com


I know how to set a breakpoint at the begin of a function.it is "break
function_name",but how to set a breakpoint at the exit/end of a function?

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[Bug breakpoints/12958] How to set a breakpoint at the exit of a function?

[qiyao at gcc dot gnu.org]

http://sourceware.org/bugzilla/show_bug.cgi?id=12958

Yao Qi <qiyao at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |qiyao at gcc dot gnu.org

--- Comment #1 from Yao Qi <qiyao at gcc dot gnu.org> 2011-07-06 01:33:03 UTC ---
(In reply to comment #0)
> I know how to set a breakpoint at the begin of a function.it is "break
> function_name",but how to set a breakpoint at the exit/end of a function?

you can dissembly the function in gdb, and get the address of exit/end of a
function, then you can set breakpoint on that address, for example, "b
*0x123456".

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[Bug breakpoints/12958] How to set a breakpoint at the exit of a function?

[wuchengping at h3c dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=12958

--- Comment #2 from 伍成平 <wuchengping at h3c dot com> 2011-07-06 03:08:21 UTC ---
(In reply to comment #0)
> I know how to set a breakpoint at the begin of a function.it is "break
> function_name",but how to set a breakpoint at the exit/end of a function?


test

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[Bug breakpoints/12958] How to set a breakpoint at the exit of a function?

[wuchengping at h3c dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=12958

--- Comment #3 from 伍成平 <wuchengping at h3c dot com> 2011-07-06 03:44:40 UTC ---
(In reply to comment #1)
> (In reply to comment #0)
> > I know how to set a breakpoint at the begin of a function.it is "break
> > function_name",but how to set a breakpoint at the exit/end of a function?
> you can dissembly the function in gdb, and get the address of exit/end of a
> function, then you can set breakpoint on that address, for example, "b
> *0x123456".

yes,I can set a breakpoint at the exit of a function in this way,but it can
only be used once, because when I modified my code,the exit address of the
function will also change,so I must modify "the gdb command file"
synchronously.I use the gdb command in this way "gdb -p $(pidof vmserver) -x
cmd.txt",and the gdb command lies in the file(cmd.txt).the file content is:
    b CDeviceMgr::queryPhyDevsInDomain
    command
    silent
    p pcUserCode
    c
    end

    c
In this way,I can watch the input parameters of the function,but how to watch
the output parameters?
I hope that I can set the exit breakpoint as simple as the entrance
breakpoint.The most important thing is that I hope,when I modified my code,the
gdb command file will be no need to modify synchronously.

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[Bug breakpoints/12958] How to set a breakpoint at the exit of a function?

[jan.kratochvil at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=12958

Jan Kratochvil <jan.kratochvil at redhat dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |jan.kratochvil at redhat
                   |                            |dot com

--- Comment #4 from Jan Kratochvil <jan.kratochvil at redhat dot com> 2011-07-07 09:30:18 UTC ---
set record insn-number-max 10000000
record
finish
reverse-step
record stop

But that works only for functions not executing too long.
GDB currently does not have the feature to find all the function exit points, I
guess it would need some GCC debug info marking extension first.

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[Bug breakpoints/12958] How to set a breakpoint at the exit of a function?

[tromey at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=12958

Tom Tromey <tromey at redhat dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |tromey at redhat dot com

--- Comment #5 from Tom Tromey <tromey at redhat dot com> 2011-07-18 16:24:45 UTC ---
There is a patch pending (maybe in assignment limbo) to add this feature.
I think it can also be done from python, perhaps with some difficulty.
On the gcc side: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49167

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