Re: [RFA] osfsolib.c: support Tru64 5.x

[Nick Duffek <nsd@redhat.com>]

On 13-May-2001, Kevin Buettner wrote:

>Is there any chance that osfsolib.c could be reworked into a solib.c
>backend?

Okay, I've just finished doing that.  It's nice to delete so much
duplicated code; the new file is 60% the size of the old one.

Is there any pending gdbint.texinfo documentation on how to implement
shared library support using solib.c?  If not, I volunteer to write a
brief explanation, while it's fresh in my mind.

I ran into a couple of problems:

1. It's necessary for the target_so_ops.current_sos callback to zero at
least the so_list.section field of each element it returns.  Otherwise,
solib_map_sections() passes a bogus pointer to build_section_table(),
which frees the bogus pointer.

What do you think about a patch like this?

Index: gdb/solist.h
===================================================================
diff -up gdb/solist.h gdb/solist.h
--- gdb/solist.h	Mon May 14 21:17:56 2001
+++ gdb/solist.h	Mon May 14 21:17:46 2001
@@ -52,7 +52,9 @@ struct so_list
 
     /* The following fields of the structure are built from
        information gathered from the shared object file itself, and
-       are initialized when we actually add it to our symbol tables.  */
+       are set when we actually add it to our symbol tables.
+
+       current_sos must initialize these fields to 0.  */
 
     bfd *abfd;
     char symbols_loaded;	/* flag: symbols read in yet? */

2. Because Tru64 doesn't use ELF binaries, "info sharedlibrary"
incorrectly infers the address size to be 32 bits, so output address
fields are too narrow:

  (gdb) inf shared
  From        To          Syms Read   Shared Object Library
  0x3ff800cd8100x3ff801ca290Yes         /usr/shlib/libc.so
  (gdb) 

Some possible fixes:
  (a) Default to 64 instead of 32 bits.
  (b) Use something like bfd_arch_bits_per_address(exec_bfd) instead of
      or in addition to bfd_get_arch_size (exec_bfd).

I'll post the new osfsolib.c patch as soon as I finish regression-testing
it.

Nick