[Dwarf-discuss] dwarf ver3.0: prologue_end and epilogue_begin bits

[Ramanaiah Nalamothu]

At present, the compiler generates assembly in that way only.

Anyhow, you clarified my doubts and gave some road lines to what i can do.
Thanks for your time.

Regards,
Ramana


On 5/22/07, David Anderson <davea42 at earthlink.net> wrote:
>
> Ramanaiah Nalamothu wrote:
>
> >    str R4,[R13,#0]
> >    mov R4,#10
> >    str R4,[R13,#+4]
> >    bl _bar
> >    .dbline -2                                                 #
> INDICATES
> > EPILOGUE_BEGIN #
> > L13:
> >    ldmfd R11,{R4,R5,R6,R7,R11,SP,R15}
> >    .dbline 0 ; func end                                   # FUNCTION
> BODY
> > END. BUT 0 IS NOT AN VALID SOURCE LINE NUMBER #
>
>
> There is a problem with the above epilogue hints, I think.
> The debugger has two responsibilities if
> the user wants to set a breakpoint just before function return (ie,
> at epilogue begin).  The first is to know an address to set the
> breakpoint.  The second is  to know what
> source line to display when the breakpoint is hit.
>
> Well, .dbline -2 in some sense allows the assembler to know the first
>   piece of info, but gives no clue about the second.
>
> So the compiler is not telling the assembler enough.
> I am just restating M. Eager's comment in longer form, I think:-)
>
>
>
> The assembly information seems (to me) to be incomplete.
> Offering no way to generate fully complete DWARF3 info.
> If it's not possible to fix the compiler right now, you could
> choose to give up setting certain line table flags you cannot
> set correctly.     Whether the debugger will notice the omission
> depends on the debugger!
>
> David Anderson
>
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