path for gdb/dwarf2read.c, support 16-bit targets in dwarf-2

[Stephane Carrez <Stephane dot Carrez at worldnet dot fr>]

Hi!

The following patch fixes GDB dwarf-2 reader to support 16-bit address
targets.

In 'dwarf2_build_psymtabs_hard' there was a hack to guess the size of the
target address. We were using the bfd 'elf_size_info::arch_size' member.
This corresponds to the ELF file arch size, not the target address size.
I suggest to use 'bfd_arch_bits_per_address' which really corresponds to
what we need.

Then, in 'read_address', we just have to read 2-bytes addresses.

I've been using this fix for a while with the 68HC11 port.

Can you integrate it?

Thanks,
	Stephane

2000-02-22  Stephane Carrez  <stcarrez@worldnet.fr>

	* dwarf2read.c (dwarf2_build_psymtabs_hard): Use
	bfd_arch_bits_per_address to get the size of addresses.
	(read_address): Read 16-bits addresses.
--- /src/gnu/cygnus/gdb/gdb/dwarf2read.c	Tue Feb 15 21:42:05 2000
+++ gdb/dwarf2read.c	Mon Feb 21 21:17:46 2000
@@ -938,7 +938,7 @@ dwarf2_build_psymtabs_hard (objfile, mai
   CORE_ADDR lowpc, highpc;
 
   /* Number of bytes of any addresses that are signficant */
-  address_significant_size = get_elf_backend_data (abfd)->s->arch_size / 8;
+  address_significant_size = bfd_arch_bits_per_address (abfd) / 8;
 
   info_ptr = dwarf_info_buffer;
   abbrev_ptr = dwarf_abbrev_buffer;
@@ -980,6 +980,7 @@ dwarf2_build_psymtabs_hard (objfile, mai
 		 (long) (beg_of_comp_unit - dwarf_info_buffer));
 	  return;
 	}
+
       if (address_size < address_significant_size)
 	{
 	  error ("Dwarf Error: bad address size (%ld) in compilation unit header (offset 0x%lx + 11).",
@@ -3487,6 +3488,9 @@ read_address (abfd, buf)
 
   switch (address_size)
     {
+    case 2:
+      retval = bfd_get_16 (abfd, (bfd_byte *) buf);
+      break;
     case 4:
       retval = bfd_get_32 (abfd, (bfd_byte *) buf);
       break;