PATCH octets vs bytes for objdump

PATCH octets vs bytes for objdump

[Timothy Wall]

This patch implements non-octet-sized bytes functionality for objdump.

  * include/dis-asm.h (struct disassemble_info): Added octets_per_byte
field and initialize it to one (1)
  * opcodes/dis-buf.c (buffer_read_memory):  Use octets_per_byte field
to adjust target address bounds checking and calculate the appropriate
octet offset into data
  * binutils/objdump.c (dump_section_header, find_symbol_for_address,
show_line, disassemble_bytes, disassemble_data, dump_data): distinguish
between octets and bytes.

Re: PATCH octets vs bytes for objdump

[Ian Lance Taylor]

   Date: Wed, 26 Jan 2000 07:28:57 -0500
   From: Timothy Wall <twall@tiac.net>

   *************** buffer_read_memory (memaddr, myaddr, len
   *** 29,39 ****
	  int length;
	  struct disassemble_info *info;
     {
       if (memaddr < info->buffer_vma
   !       || memaddr - info->buffer_vma + length > info->buffer_length)
	 /* Out of bounds.  Use EIO because GDB uses it.  */
	 return EIO;
   !   memcpy (myaddr, info->buffer + (memaddr - info->buffer_vma), length);
       return 0;
     }

   --- 29,45 ----
	  int length;
	  struct disassemble_info *info;
     {
   +   int opb = info->octets_per_byte;
   +   int end_addr_offset = length / opb;
   +   int max_addr_offset = info->buffer_length / opb; 
   +   int octets = (memaddr - info->buffer_vma) * opb;
   + 
       if (memaddr < info->buffer_vma
   !       || memaddr + end_addr_offset > info->buffer_vma + max_addr_offset)
	 /* Out of bounds.  Use EIO because GDB uses it.  */
	 return EIO;
   !   memcpy (myaddr, info->buffer + octets, length);
   ! 
       return 0;
     }

Note that the original version of the condition was careful to never
form an address which extended past the end of the buffer.  The new
condition does not preserve that property, because memaddr +
end_addr_offset might be past the end of the buffer.  ISO C does not
guarantee that you can form an address beyond the end of a buffer.  I
admit that this is just a quibble.

Ian

Re: PATCH octets vs bytes for objdump

[Ian Lance Taylor]

   Date: Wed, 26 Jan 2000 07:28:57 -0500
   From: Timothy Wall <twall@tiac.net>

   +   int opb = bfd_octets_per_byte(abfd);

Oh yeah--use a space before a left paren in a function call in GNU
sources.

Ian

Re: PATCH octets vs bytes for objdump

[Timothy Wall]

So while algebraically they are equivalent, ISO C-ically they're not.  Good
point.

The condition should be:

    memaddr - info->buffer_vma + end_addr_offset > max_addr_offset

instead of:

    memaddr + end_addr_offset > info->buffer_vma + max_addr_offset


T.

Ian Lance Taylor wrote:

>    Date: Wed, 26 Jan 2000 07:28:57 -0500
>    From: Timothy Wall <twall@tiac.net>
>
>    *************** buffer_read_memory (memaddr, myaddr, len
>    *** 29,39 ****
>           int length;
>           struct disassemble_info *info;
>      {
>        if (memaddr < info->buffer_vma
>    !       || memaddr - info->buffer_vma + length > info->buffer_length)
>          /* Out of bounds.  Use EIO because GDB uses it.  */
>          return EIO;
>    !   memcpy (myaddr, info->buffer + (memaddr - info->buffer_vma), length);
>        return 0;
>      }
>
>    --- 29,45 ----
>           int length;
>           struct disassemble_info *info;
>      {
>    +   int opb = info->octets_per_byte;
>    +   int end_addr_offset = length / opb;
>    +   int max_addr_offset = info->buffer_length / opb;
>    +   int octets = (memaddr - info->buffer_vma) * opb;
>    +
>        if (memaddr < info->buffer_vma
>    !       || memaddr + end_addr_offset > info->buffer_vma + max_addr_offset)
>          /* Out of bounds.  Use EIO because GDB uses it.  */
>          return EIO;
>    !   memcpy (myaddr, info->buffer + octets, length);
>    !
>        return 0;
>      }
>
> Note that the original version of the condition was careful to never
> form an address which extended past the end of the buffer.  The new
> condition does not preserve that property, because memaddr +
> end_addr_offset might be past the end of the buffer.  ISO C does not
> guarantee that you can form an address beyond the end of a buffer.  I
> admit that this is just a quibble.
>
> Ian