RE: [Gcl-devel] BFD related issues - belated reply.

[Mike Thomas]

Hi Aurelien

| Sure I'd like to help out.

Thanks for that.

|  I know about this
| bfdtest.c file, which I happen to have used myself to
| test BFD dynamic loading for Mac OS X.  Unfortunately,
| I'm absolutely unacquainted to PE, which is probably
| the object file format you're using.  What I'd do is
| look at this in gdb to see what exactly is happening.
| As I don't have access to any Windows machine running
| cygwin or mingw (or whatever you're using), I can't
| look into the matter myself.  Could you provide a
| stack trace along with a generous context ?  Then, as
| I've been working on BFD for quite some time now,
| maybe I can come up with a solution.

Sounds good.

The example oputput I sent you yesterday used the standard MinGW32 libbfd
etc.

I built bfdtest from the GCL CVS bfd build today and had a complete
disaster - the exe_bfd structure gets trashed during bfd_openr() before the
executable symbol table is even built. I'll try and get to the bottom of why
it went so badly wrong before I bring you in on the debugging.


| >From my experience, the code in bfdtest.c (and in
| sfasfbfd.c) is fairly experimental, and heavily relies
| on the behavior for ELF.  Is BFD reputedly working for
| PE ?

MinGW32 and Cygwin each use it so, yes, but apparently not the parts we
need.


| I know that there's support for Windows DLL in
| GNU ld, so I suspect there should be some kind of
| minimal support for BFD as well.  Fixing the matter
| might not be that much of a headache.

For you maybe!!

Cheers

Mike Thomas.


$ gdb --directory binutils/bfd --directory binutils/libiberty/ ./bfdtest.exe
GNU gdb 6.0
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welcome to change it and/or distribute copies of it under certain
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Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i686-pc-mingw32"...
(gdb) b bfd_init
Breakpoint 1 at 0x407033: file init.c, line 50.
(gdb) l
227
228             fprintf ( stderr, "mnotice\n");
229             return MY_BFD_FALSE;
230
231         }
232
233
234     int main ( int argc, char ** argv )
235     {
236         int init_address=-1;
(gdb) set args ./unixport/raw_gcl.exe ./lsp/gcl_sloop.o
(gdb) r
Starting program: c:\cvs\head\gcl-bfd/./bfdtest.exe ./unixport/raw_gcl.exe
./lsp
/gcl_sloop.o
In BFD fast load test. Reloc_howto_type size 52
BUILDING EXECUTABLE SYMBOL TABLE FOR ./unixport/raw_gcl.exe

Breakpoint 1, 0x00407033 in bfd_init () at init.c:50
50      {
(gdb) n
build_symbol_table_bfd (oname=0x3d2cbc "./unixport/raw_gcl.exe")
    at bfdtest.c:21
21          if ( ! ( exe_bfd = bfd_openr ( oname, 0 ) ) ) {
(gdb) n
26          if ( ! bfd_check_format ( exe_bfd, bfd_object ) ) {
(gdb) n
31          if ( !(link_info.hash = bfd_link_hash_table_create (
exe_bfd ) ) ) {

(gdb) p oname
$1 = 0x3d2cbc "./unixport/raw_gcl.exe"
(gdb) p exe_bfd
$2 = (bfd *) 0x3d5058
(gdb) p *exe_bfd
$3 = {id = 4009148, filename = 0x41c990 "l?A", xvec = 0x77c5ace0,
  iostream = 0x1, cacheable = 1, target_defaulted = 4018264,
  lru_prev = 0x3d5058, lru_next = 0x9, where = 0, opened_once = 0,
  mtime_set = 0, mtime = 0, ifd = 1, format = bfd_object, direction = 314,
  flags = 0, origin = 0, output_has_begun = 4026664, section_htab = {
    table = 0xfd3, size = 4230544, newfunc = 0x3d6100, memory = 0x3d613c},
  sections = 0x3d6440, section_tail = 0x6, section_count = 4198400,
  start_address = 11909, symcount = 0, outsymbols = 0x413cd0, dynsymcount =
0,
  arch_info = 0x0, arelt_data = 0x0, my_archive = 0x0, next = 0x0,
  archive_head = 0x0, has_armap = 0, link_next = 0x3d51f0, archive_pass = 0,
  tdata = {aout_data = 0x3d2d50, aout_ar_data = 0x3d2d50,
    oasys_obj_data = 0x3d2d50, oasys_ar_data = 0x3d2d50,
    coff_obj_data = 0x3d2d50, pe_obj_data = 0x3d2d50,
    xcoff_obj_data = 0x3d2d50, ecoff_obj_data = 0x3d2d50,
    ieee_data = 0x3d2d50, ieee_ar_data = 0x3d2d50, srec_data = 0x3d2d50,
    ihex_data = 0x3d2d50, tekhex_data = 0x3d2d50, elf_obj_data = 0x3d2d50,
    nlm_obj_data = 0x3d2d50, bout_data = 0x3d2d50, mmo_data = 0x3d2d50,
    sun_core_data = 0x3d2d50, sco5_core_data = 0x3d2d50,
    trad_core_data = 0x3d2d50, som_data = 0x3d2d50, hpux_core_data =
0x3d2d50,
    hppabsd_core_data = 0x3d2d50, sgi_core_data = 0x3d2d50,
    lynx_core_data = 0x3d2d50, osf_core_data = 0x3d2d50,
    cisco_core_data = 0x3d2d50, versados_data = 0x3d2d50,
    netbsd_core_data = 0x3d2d50, mach_o_data = 0x3d2d50,
---Type <return> to continue, or q <return> to quit---
    mach_o_fat_data = 0x3d2d50, pef_data = 0x3d2d50, pef_xlib_data =
0x3d2d50,
    sym_data = 0x3d2d50, any = 0x3d2d50}, usrdata = 0xabababab,
  memory = 0xabababab}
(gdb) p _bfd_link_hash_table_create
No symbol "_bfd_link_hash_table_create" in current context.
(gdb) p exe_bfd->xvec
$4 = (const struct bfd_target *) 0x77c5ace0
(gdb) p exe_bfd->xvec->_bfd_link_hash_table_create
$5 = (struct bfd_link_hash_table *(*)()) 0
(gdb)