Re: About bfd in gdb

Re: About bfd in gdb

[libra]

At first, thanks for your reply.

After survey the gdb source code,i can roughly take the gdb source code into 
two part, one is gdb and the other is sim. (Maybe now, it must add the third 
part that is binutils(bfd and opcodes))

My question is :
Because the gdb source code is complex, i do not know how these two part(gdb 
and sim) communicate with each other.In other word, which file is the 
interface that can connect these two part.Once i add a new simulator(sim ,ISA)
into the gdb source code, the gdb can connct to my new sim,and run my program 
on the new sim and debug it. Any documentation can reference


My idea is that the gdb is just an interface that connect to the simulator(sim)
, after doing that i can run my own program and debug it (ex:use arm-elf-gdb 
or just use the simulator arm-elf-run).

                                                            thanks a lot!!


----- Original Message ----- 
From: "Ramana Radhakrishnan" <ramana.radhakrishnan@codito.com>
To: "libra" <mr924352@cs.nthu.edu.tw>
Cc: <gdb@sources.redhat.com>
Sent: Sunday, July 04, 2004 10:00 PM
Subject: Re: About bfd in gdb


> > Why we must build the bfd and opcodes parts that the same as in 
> > binutils (like
> > archures.c reloc.c arm-dis.c and arm-opc.h and so on)
> >
> > My idea is that :
> > We just need to build bfd inoder to recognize the input file format,then
> > i can use the gdb to connect to simulator(sim),after that, I can run 
> > my own
> > program.
> > So, the aboved mentioned file (ex: arm-dis.c and arm-opc.h), why is 
> > those file
> > must be built again. It seem does not be used in gdb.
> 
> This would be needed for doing all the reading of the object file. The 
> most common cases that come to mind off the cuff are:
> 
> 1. The implementation of the disassembling would be based on the 
> disassembling in the opcodes library.
>    Just taking your example. For the ARM if you trace the disassembling 
> function in arm-tdep.c you would observe that it returns the function
>    print_insn_little_arm or print_insn_big_arm depending on the 
> endian-ness . These functions happen to be defined in opcodes/arm-dis.c and
>    there would be a dependency between the two of them.
>     "code pasted below for your reference "
>   
> CVS today ..
>     File: gdb/ arm-tdep.c
>     Function :
> 
>   gdb_print_insn_arm (bfd_vma memaddr, disassemble_info *info)
>   {
> 
>     <blah>
>    
> 
>  if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG)
>     return print_insn_big_arm (memaddr, info);
>   else
>     return print_insn_little_arm (memaddr, info);
>   }
> 
>   and you can find both these functions defined in opcodes/arm-dis.c 
> 
> 
> 2.  Construction of minimal symbol tables for the debugger.
> 3.  Reading any information from the executable file would use the bfd 
> library.Since all information about the executable for the debugger 
> happens to be in the
> executable file in the case of the ELF file format gdb would 
> automatically have a dependency with the opcodes and bfd library.
> 
> cheers
> Ramana
> 
> ---
> Ramana Radhakrishnan
> GNU Tools
> codito ergo sum (www.codito.com )
> 
> 

Re: About bfd in gdb

[Andrew Cagney]

Have a look at include/gdb/remote-sim.h

Andrew

> At first, thanks for your reply.
> 
> After survey the gdb source code,i can roughly take the gdb source code into 
> two part, one is gdb and the other is sim. (Maybe now, it must add the third 
> part that is binutils(bfd and opcodes))
> 
> My question is :
> Because the gdb source code is complex, i do not know how these two part(gdb 
> and sim) communicate with each other.In other word, which file is the 
> interface that can connect these two part.Once i add a new simulator(sim ,ISA)
> into the gdb source code, the gdb can connct to my new sim,and run my program 
> on the new sim and debug it. Any documentation can reference
> 
> 
> My idea is that the gdb is just an interface that connect to the simulator(sim)
> , after doing that i can run my own program and debug it (ex:use arm-elf-gdb 
> or just use the simulator arm-elf-run).
> 
>                                                             thanks a lot!!
> 
> 

About bfd in gdb

[libra]

Hello,all:

About the gdb source code, I have some questions.

I will use "ARM" for my example.

In the gdb source code architecture,when you build the gdb(ex: target=arm-efl)
,you can find that first you will build bfd and opcodes that the same as 
binutils, then build the gdb and sim.

My question is that :

Why we must build the bfd and opcodes parts that the same as in binutils (like 
archures.c reloc.c arm-dis.c and arm-opc.h and so on)

My idea is that :
We just need to build bfd inoder to recognize the input file format,then
i can use the gdb to connect to simulator(sim),after that, I can run my own 
program.

So, the aboved mentioned file (ex: arm-dis.c and arm-opc.h), why is those file 
must be built again. It seem does not be used in gdb.


                                                      thanks a lot!!

Re: About bfd in gdb

[Ramana Radhakrishnan]

Hi there,

<snip>

> <>
> Why we must build the bfd and opcodes parts that the same as in 
> binutils (like
> archures.c reloc.c arm-dis.c and arm-opc.h and so on)
>
> My idea is that :
> We just need to build bfd inoder to recognize the input file format,then
> i can use the gdb to connect to simulator(sim),after that, I can run 
> my own
> program.
> So, the aboved mentioned file (ex: arm-dis.c and arm-opc.h), why is 
> those file
> must be built again. It seem does not be used in gdb.

This would be needed for doing all the reading of the object file. The 
most common cases that come to mind off the cuff are:

1. The implementation of the disassembling would be based on the 
disassembling in the opcodes library.
   Just taking your example. For the ARM if you trace the disassembling 
function in arm-tdep.c you would observe that it returns the function
   print_insn_little_arm or print_insn_big_arm depending on the 
endian-ness . These functions happen to be defined in opcodes/arm-dis.c and
   there would be a dependency between the two of them.
    "code pasted below for your reference "
  
CVS today ..
    File: gdb/ arm-tdep.c
    Function :

  gdb_print_insn_arm (bfd_vma memaddr, disassemble_info *info)
  {

    <blah>
   

 if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG)
    return print_insn_big_arm (memaddr, info);
  else
    return print_insn_little_arm (memaddr, info);
  }

  and you can find both these functions defined in opcodes/arm-dis.c 	


2.  Construction of minimal symbol tables for the debugger.
3.  Reading any information from the executable file would use the bfd 
library.Since all information about the executable for the debugger 
happens to be in the
executable file in the case of the ELF file format gdb would 
automatically have a dependency with the opcodes and bfd library.

cheers
Ramana

---
Ramana Radhakrishnan
GNU Tools
codito ergo sum (www.codito.com )