Re: vast numbers of unimplemented MI commands.

Re: vast numbers of unimplemented MI commands.

[Jim Ingham]

On Sep 18, 2003, at 8:30 AM, gdb-digest-help@sources.redhat.com wrote:

>
>
>>
>> Hi,
>>
>> I guess this seems ok, I just hate to see stuff like this.
>>
>>    But if you can come up with a clean Interface(set of methods) of
>>    what you need we could work things and put it in the CDI and  
>> implement
>>    it in the GDB/MI plugin.  The annoying thing is that GDB/MI does  
>> not
>>    have any "mi" command for this, so we will have to send "cli"  
>> command
>>    and do weird parsing on the output.
>>
>> from the eclipse mailing lists. Seeing this makes me think that the
>> whole community is not understanding that we need to have clean
>> interfaces between GDB and the front ends.
>>
>
> Amen to that!!
>
>> Developers that find a "missing hole" in GDB, don't seem to have the
>> desire to fix the hole when they can easily find a work around.
>> IMO, most developers don't have enough time to fix there own
>> front end and then go fix the debugger there integrating with.
>
> I hear you !!! 8-)
>
>> I think GDB should support a proper MI interface for front ends, and
>> thats the only way front ends should be able to communicate with it.
>> Adding the -interpreter console was probably the main cause in  
>> allowing
>> front ends to cheat there way past the MI interface.

I don't think that is right.  You could always issue console commands  
straight to the mi, THAT is the real way to cheat (and I agree that  
should be closed off).  The console interpreter (and -interpreter-exec  
console) fulfills a very useful purpose: satisfying folks who like a  
console interface to gdb as well as the GUI.  We would probably get  
assassinated right quick if we were to try to take this out of Xcode  
(used to be Project Builder - another Marketing person earns their  
salary!) .

Note that we have had to fix up a few things in the MI as we have gone  
along with Xcode, and most of those fixes are in the Apple sources not  
in the main FSF repository.  We are short-staffed for what we need to  
do here, which sort of explains why we haven't gotten to submitting our  
sources back to the FSF - experience has shown that to be very time  
consuming.  But you can get the Apple sources from the Apple Darwin  
site, or from the opendarwin site.  If you are serious about using the  
MI it might be worth your while to have a look here, since Xcode is the  
only fairly mature GUI the uses the MI...

>>
>
> Agreed, but not for the same reasons.  We do not use the  
> "-interpreter-exec console"
> because it turns out to be useless.  The first attempt was to satisfy  
> the CLI users
> within the IDE, so a prompt was given.  But the problem is to  
> synchronize the IDE,
> let see a scenario, the "show":
>
> - scenario 1 (show):
>
> # gdb -i mi hello
> ...
> (gdb)
> show auto-solib
> &"show auto-solib\n"
> ^done,value="on"
> (gdb)
>
> The problem here, and with many other commands, is that the  
> information is return in MI jargon
> only,  so the user will not see it.  To do this correctly we would  
> need a cli interpreter
> that will pretty print the output of any commands(no fun job, knowin  
> the annoying cli syntax of gdb).
>

I don't understand this comment.  This is exactly what  
-interpreter-exec console is for.  If the user issues this sort of  
console command, you just echo back whatever it sends to your console  
window.  You can also annotate if they do anything of other interest to  
the GUI (proceeding the inferior, setting breakpoints, etc...)  Note  
that to make parsing the output from gdb, I added a "console-quoted"  
interpreter that sends stuff back in the cli pretty-printing, but the  
output strings are packaged up in MI format.  So you get something  
like:

-interpreter-exec console-quoted "info func"
~"All defined functions:\n"
~"\nFile "
~"/SourceCache/Csu/Csu-46/crt.c:\n"
~"void _start(int, char **, char **);\n"
~"static void _call_mod_init_funcs(void);\n"
...
^done,time={wallclock="1.83584",user="1.02000",system="0.11000",start="1 
063903591.475599",end="1063903593.311440"}
(gdb)


This means that if the response from a command happens to start with  
^done or something like that, you won't get confused...

I still have some cleanup to do on this, because there are various  
places (like the show command) where the command ignores the uiout and  
prints straight to gdbstdout (grrr....)  But this makes it pretty easy  
to handle this sort of thing.

>
> - scenario 2 (show/next):
>
> The problem is reverse when doing -interpreter-exec, the information  
> not is not in MI,
> this is illustrate when doing a "next"
>
> (gdb)
> -interpreter-exec console next
> ~"41\t\tchar array[2][2] = { 'a', 'b', 'c'};\n"
> ^done
> (gdb)
>
> The front-end fall out of step with gdb and no longer has relevant  
> information.
> However doing CLI without -interpreter-exec is good.
>
> (gdb)
> next
> &"next\n"
> ^done,reason="end-stepping-range",thread- 
> id="0",frame={addr="0x0804846e",func="main",args=[{name="argc",value="1 
> "},{name="argv",value="0xbfffeb54"}],file="hello.c",line="40"}
> (gdb)
>
> The front-end can keep up.

This is just a hole in the interpreter-exec console implementation.  We  
tarted this up a bit on our end, so you get:

-interpreter-exec console-quoted next
^stepping
^running
(gdb)
*stopped,time={wallclock="0.01305",user="0.00000",system="0.02000",start 
="1063903739.568366",end="1063903739.581413"},reason="end-stepping- 
range",thread-id="1"

I forget why the GUI guys wanted the ^stepping as well as the ^running,  
for regularity it would probably be better to leave that out.  But with  
this modification, it is very easy to keep the GUI in sync with the  
CLI.  The Xcode console interpreter actually works pretty well, and  
very seldom gets out of sync with the GUI.

>
>> The problem is, every *real* world front end to GDB is doomed to end  
>> up
>> using a mix of MI commands and CLI commands. If GDB is ever released
>> in such a way that the CLI output is changed, all existing front ends
>> will break. Including the ones that use MI.

This has not been our experience.  Xcode doesn't use any CLI commands,  
provided you don't consider "-interpreter-exec" a console command.  It  
took some work on our part to get this all going, but it is very  
achievable.

>>
>> What is the best solution? ...
>>
>
> Good question.  Although I like to complain 8-)
> The move toward MI is a good one, it is much cleaner, kudos to gdb  
> folks.

We have had pretty good success with the MI so far...

Jim
--
Jim Ingham                                   jingham@apple.com
Developer Tools
Apple Computer

Re: vast numbers of unimplemented MI commands.

[Alain Magloire]

[some lines deleted]
....

> I don't think that is right.  You could always issue console commands  
> straight to the mi, THAT is the real way to cheat (and I agree that  
> should be closed off).  The console interpreter (and -interpreter-exec  
> console) fulfills a very useful purpose: satisfying folks who like a  
> console interface to gdb as well as the GUI.  We would probably get  
> assassinated right quick if we were to try to take this out of Xcode  
> (used to be Project Builder - another Marketing person earns their  
> salary!) .
> 
> Note that we have had to fix up a few things in the MI as we have gone  
> along with Xcode, and most of those fixes are in the Apple sources not  
> in the main FSF repository.  We are short-staffed for what we need to  

And for the fixes ... thank you !!!

> do here, which sort of explains why we haven't gotten to submitting our  
> sources back to the FSF - experience has shown that to be very time  
> consuming.  But you can get the Apple sources from the Apple Darwin  
> site, or from the opendarwin site.  If you are serious about using the  
> MI it might be worth your while to have a look here, since Xcode is the  
> only fairly mature GUI the uses the MI...
> 

I disagree 8-).
There are a few that uses MI and do a good job at it.
This is not saying Xcode is not a great product of course 8-)
I do not have a Mac to try it, but any URL handy with good snapshots?
or just docs on Xcode ?

[...]

> I don't understand this comment.  This is exactly what  
> -interpreter-exec console is for.  If the user issues this sort of  
> console command, you just echo back whatever it sends to your console  
> window.  You can also annotate if they do anything of other interest to  
> the GUI (proceeding the inferior, setting breakpoints, etc...)  Note  
> that to make parsing the output from gdb, I added a "console-quoted"  
> interpreter that sends stuff back in the cli pretty-printing, but the  
> output strings are packaged up in MI format.  So you get something  
> like:
> 
> -interpreter-exec console-quoted "info func"
> ~"All defined functions:\n"
> ~"\nFile "
> ~"/SourceCache/Csu/Csu-46/crt.c:\n"
> ~"void _start(int, char **, char **);\n"
> ~"static void _call_mod_init_funcs(void);\n"
> ...
> ^done,time={wallclock="1.83584",user="1.02000",system="0.11000",start="1 
> 063903591.475599",end="1063903593.311440"}
> (gdb)
> 
> 
> This means that if the response from a command happens to start with  
> ^done or something like that, you won't get confused...
> 

Yes this is the answer to our prayers.
"-interpreter-exec console" does not do anything for us since we
can not use it to sync the UI from the user input.
However "-interpreter-exec console-quoted", at least, how you
describe it is what we want.


> I still have some cleanup to do on this, because there are various  
> places (like the show command) where the command ignores the uiout and  
> prints straight to gdbstdout (grrr....)  But this makes it pretty easy  
> to handle this sort of thing.
> 

8-)

>

[...]

> This is just a hole in the interpreter-exec console implementation.  We  
> tarted this up a bit on our end, so you get:
> 
> -interpreter-exec console-quoted next
> ^stepping
> ^running
> (gdb)
> *stopped,time={wallclock="0.01305",user="0.00000",system="0.02000",start 
> ="1063903739.568366",end="1063903739.581413"},reason="end-stepping- 
> range",thread-id="1"
> 

Yes, Yes , Yes !
Now __This__ is usefull.

> I forget why the GUI guys wanted the ^stepping as well as the ^running,  
> for regularity it would probably be better to leave that out.  But with  
>

I can guess:
^stepping and ^running are vital for the IDE to maintain its state
without them "console-quoted" is as useless as "-interpreter-exec console".
There is a difference between "next" and "continue"(for the IDE) and 
the ^running is if the next statement is blocking, the IDE will know that
it is running.

> this modification, it is very easy to keep the GUI in sync with the  
> CLI.  The Xcode console interpreter actually works pretty well, and  
> very seldom gets out of sync with the GUI.
>

In any case ... very nice improvements.

[...]

> This has not been our experience.  Xcode doesn't use any CLI commands,  
> provided you don't consider "-interpreter-exec" a console command.  It  
> took some work on our part to get this all going, but it is very  
> achievable.
> 

Well then how do you deal with shared libraries ? How do you do
deferred breakpoints? how do you load a shared library symbol ?
How do you get the signal handlers? How do you set the handle for a signal ?
etc, etc  ...

There are currently no MI counterparts ... at least in the FSF version.
And the console prompt is a problem that "-interpreter-exec console"
does not solve, .. but looking forward for "-interpreter-exec console-quoted".

Re: open watcom

[y2bismil]

Hi Jim Blandy,
Here is the output of the object dump
***********************************************
C:\src\watcom>objdump -h test2.exe

test2.exe:     file format pei-i386

Sections:
Idx Name          Size      VMA       LMA       File off  Algn
  0 AUTO          00008000  00401000  00401000  00000400  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
  1 .idata        00000600  00409000  00409000  00008400  2**2
                  CONTENTS, ALLOC, LOAD, DATA
  2 DGROUP        00001200  0040a000  0040a000  00008a00  2**2
                  CONTENTS, ALLOC, LOAD, DATA
  3 .bss          00000a00  0040c000  0040c000  00000000  2**4
                  ALLOC
  4 .reloc        00000800  0040d000  0040d000  00009c00  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, DATA, DEBUGGING
***********************************************

Yamin


----------------------------------------
This mail sent through www.mywaterloo.ca

open watcom

[y2bismil]

Hey guys,

We're exploring a new development environment here, and as part of the 
migration process, I was wondering if its possible to debug code genered by the 
open watcom compiler using gdb.  I've tried unsuccessfully setting the 
debugging in watcom to:  watcom, codeview, and dwarf, but to no avail.

Does anyone know the location of a list of supported debug format by gdb?

thanks all,

Yamin



----------------------------------------
This mail sent through www.mywaterloo.ca

Re: open watcom

[Michael Elizabeth Chastain]

> Does anyone know the location of a list of supported debug format by gdb?

dwarf 1, dwarf 1+
dwarf 2
stabs, stabs+
coff, xcoff, xcoff+
mdebug

Also, I'm not sure whether "hp" is an object code format or a debug
format.

Michael C

Re: open watcom

[Joel Brobecker]

> Also, I'm not sure whether "hp" is an object code format or a debug
> format.

HP32 uses SOM (object format). The Debug format used is then stabs.
HP64 uses ELF, in which case you have the choice between stabs or
dwarf2.

-- 
Joel

Re: open watcom

[y2bismil]

Thanks Michael,

open watcom does support dwarf1, and so I tried that, but still nothing.  GDB 
just keeps saying it can't find any debug information.  Shuold gdb 
automatically detect the debug type, or is there an option?

Thanks

Quoting Michael Elizabeth Chastain <mec@shout.net>:
> > Does anyone know the location of a list of supported debug format by gdb?
> 
> dwarf 1, dwarf 1+
> dwarf 2
> stabs, stabs+
> coff, xcoff, xcoff+
> mdebug
> 
> Also, I'm not sure whether "hp" is an object code format or a debug
> format.
> 
> Michael C
> 


Quoting Michael Elizabeth Chastain <mec@shout.net>:

> > Does anyone know the location of a list of supported debug format by gdb?
> 
> dwarf 1, dwarf 1+
> dwarf 2
> stabs, stabs+
> coff, xcoff, xcoff+
> mdebug
> 
> Also, I'm not sure whether "hp" is an object code format or a debug
> format.
> 
> Michael C
> 




----------------------------------------
This mail sent through www.mywaterloo.ca

Re: open watcom

[Michael Elizabeth Chastain]

Check the switches for open watcom.  It's likely that you need to
specify debug switches both at compile time *and* link time when
building your program.

gdb automatically detects debug type.

I know that other people have used dwarf 1, and I ran the gdb test
suite on it earlier this year.  So I know that gdb does automatically
detect and use dwarf-1 debug information with gcc -gdwarf.

Michael C

Re: open watcom

[y2bismil]

Yep, I've rechecked my options, and in both the compile and link time, I have 
the debug swtich to use DWARF.

Yamin

Quoting Michael Elizabeth Chastain <mec@shout.net>:

> Check the switches for open watcom.  It's likely that you need to
> specify debug switches both at compile time *and* link time when
> building your program.
> 
> gdb automatically detects debug type.
> 
> I know that other people have used dwarf 1, and I ran the gdb test
> suite on it earlier this year.  So I know that gdb does automatically
> detect and use dwarf-1 debug information with gcc -gdwarf.
> 
> Michael C
> 




----------------------------------------
This mail sent through www.mywaterloo.ca

Re: open watcom

[Jim Blandy]

y2bismil@engmail.uwaterloo.ca writes:
> Yep, I've rechecked my options, and in both the compile and link time, I have 
> the debug swtich to use DWARF.

Can you post the output produced by running 'objdump -h' on your
executable file?

Re: open watcom

[Michael Elizabeth Chastain]

Well, I think you are stuck:

  gdb doesn't support open watcom.
  open watcom has no documentation that I could find about gdb.
  google "open watcom gdb" did not find anybody talking about
    using open watcom and gdb.

You could ask on an open watcom list if open watcom interacts with gdb,
and if anyone has actually used that combination.

I suggest that you check out the debugger that comes with Open Watcom.

I will file an enhancement request against gdb to add support for
open watcom.  It is a lot of work to add support for a new compiler;
someone would have to volunteer to do this work.

Open Watcom is licensed under the Sybase Open Watcom Public License,
which is an OSI-approved open source license.  So I think it would be
reasonable to consider adding support for this compiler, if a volunteer
steps up.

Michael C