IEEE 695 symbol support for GDB/BFD

IEEE 695 symbol support for GDB/BFD

[Chris Lewkowski]

Hi,

I have been trying to use GDB with IEEE 695 symbol
object file for 
debugging a m68k remote board.  I configured GDB with
a target of 
m68k-motorola-ieee and that built fine.  When I run
GDB and load an IEEE 695 
file I get the following error:

I'm sorry, Dave, I can't do that.  Symbol format
'ieee' unknown.

I tracked this down to the function find_sym_fns() in
file symfile.c.  
After doing some more investigation I believe that
GDB/BFD does not 
have any methods for reading these types of symbol
files, although it does 
recognise the format.  I believe that the file
ieeeread.c (and 
functionality of course) will need to be created for
GDB as well as supporting 
read functions in the BFD library.  I am considering
creating this 
functionality but have a few questions first:

1) Has anyone attempted this before?

2) Does what I have described above seem like the
correct path to take 
to support this object/executable file format?  Can
someone give me 
some pointers on the best way to add this
functionality?

3) Does anyone have any additional (to the standard
gdb docs) relevant 
information about the functionality of GDB's symbol
interpreting 
engine? and what steps should be taken to do this?

I have used the binutils program objdump and that has
the capability to 
read the IEEE 695 symbol files.  So hopefully I can
re-use a lot of the 
code from there.

Any help would be greatly appreciated,

Thanks,

Chris



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Re: IEEE 695 symbol support for GDB/BFD

[Elena Zannoni]

Chris Lewkowski writes:
 > Hi,
 > 
 > I have been trying to use GDB with IEEE 695 symbol
 > object file for 
 > debugging a m68k remote board.  I configured GDB with
 > a target of 
 > m68k-motorola-ieee and that built fine.  When I run
 > GDB and load an IEEE 695 
 > file I get the following error:
 > 
 > I'm sorry, Dave, I can't do that.  Symbol format
 > 'ieee' unknown.
 > 
 > I tracked this down to the function find_sym_fns() in
 > file symfile.c.  
 > After doing some more investigation I believe that
 > GDB/BFD does not 
 > have any methods for reading these types of symbol
 > files, although it does 
 > recognise the format.  I believe that the file
 > ieeeread.c (and 
 > functionality of course) will need to be created for
 > GDB as well as supporting 
 > read functions in the BFD library.  I am considering
 > creating this 
 > functionality but have a few questions first:
 > 
 > 1) Has anyone attempted this before?
 > 

I see that this was developed for the HP emulator, and the debugger
support remained proprietary, so no, there never was any such reader
in gdb. Seems like people use m68k-coff and then translate the files
to ieee-695 for use of the emulator.
m68k-coff-objcopy -O ieee --debugging <file> <file.x> does this.

 > 2) Does what I have described above seem like the
 > correct path to take 
 > to support this object/executable file format?  Can
 > someone give me 
 > some pointers on the best way to add this
 > functionality?
 > 

There are a number of other readers in gdb, you could look at
elfread.c, coffread.c, for instance. I would avoid looking at *read.c
files that haven't been changed recently (look at the ChangeLogs to
see this).

 > 3) Does anyone have any additional (to the standard
 > gdb docs) relevant 
 > information about the functionality of GDB's symbol
 > interpreting 
 > engine? and what steps should be taken to do this?
 > 

Sigh, no. All we have is the source code....

 > I have used the binutils program objdump and that has
 > the capability to 
 > read the IEEE 695 symbol files.  So hopefully I can
 > re-use a lot of the 
 > code from there.
 > 
 > Any help would be greatly appreciated,
 > 

Just send questions to this list, and if you want to contribute your
work, make sure you have a copyright assignment with the FSF in place.

Elena


 > Thanks,
 > 
 > Chris
 > 
 > 
 > 
 > __________________________________________________
 > Do You Yahoo!?
 > Yahoo! Health - Feel better, live better
 > http://health.yahoo.com