gdb/i386-dicos-tdep.c

   1 /* Target-dependent code for DICOS running on i386's, for GDB.
   2
   3    Copyright (C) 2008, 2009 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "osabi.h"
  22 #include "gdb_string.h"
  23 #include "solib.h"
  24 #include "solib-target.h"
  25 #include "inferior.h"
  26
  27 static CORE_ADDR
  28 i386_dicos_push_dummy_code (struct gdbarch *gdbarch,
  29                             CORE_ADDR sp, CORE_ADDR funaddr,
  30                             struct value **args, int nargs,
  31                             struct type *value_type,
  32                             CORE_ADDR *real_pc, CORE_ADDR *bp_addr,
  33                             struct regcache *regcache)
  34 {
  35   int bplen;
  36   CORE_ADDR bppc = sp;
  37
  38   gdbarch_breakpoint_from_pc (gdbarch, &bppc, &bplen);
  39   *bp_addr = sp - bplen;
  40   *real_pc = funaddr;
  41
  42   return *bp_addr;
  43 }
  44
  45 static void
  46 i386_dicos_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
  47 {
  48   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  49
  50   set_solib_ops (gdbarch, &solib_target_so_ops);
  51
  52   /* Every process, although has its own address space, sees the same
  53      list of shared libraries.  */
  54   set_gdbarch_has_global_solist (gdbarch, 1);
  55
  56   /* There's no (standard definition of) entry point or a guaranteed
  57      text location we could find with a symbol where to place the call
  58      dummy, so we put it on the stack.  */
  59   set_gdbarch_call_dummy_location (gdbarch, ON_STACK);
  60   set_gdbarch_push_dummy_code (gdbarch, i386_dicos_push_dummy_code);
  61
  62   /* DICOS rewinds itself.  Need to override the i386 default which is
  63      to decrement the PC.  */
  64   set_gdbarch_decr_pc_after_break (gdbarch, 0);
  65 }
  66
  67 /* Look in the elf symbol table of ABFD for a symbol named WANTED.
  68    Return true if found.  */
  69 static int
  70 i386_dicos_bfd_has_symbol_p (bfd *abfd, const char *wanted)
  71 {
  72   long storage_needed;
  73   int ret = 0;
  74   asymbol **symbol_table = NULL;
  75
  76   storage_needed = bfd_get_symtab_upper_bound (abfd);
  77   if (storage_needed < 0)
  78     {
  79       warning (_("Can't read elf symbols from %s: %s"), bfd_get_filename (abfd),
  80                bfd_errmsg (bfd_get_error ()));
  81       return 0;
  82     }
  83
  84   if (storage_needed > 0)
  85     {
  86       long i, symcount;
  87
  88       symbol_table = xmalloc (storage_needed);
  89       symcount = bfd_canonicalize_symtab (abfd, symbol_table);
  90
  91       if (symcount < 0)
  92         warning (_("Can't read elf symbols from %s: %s"),
  93                  bfd_get_filename (abfd),
  94                  bfd_errmsg (bfd_get_error ()));
  95       else
  96         {
  97           for (i = 0; i < symcount; i++)
  98             {
  99               asymbol *sym = symbol_table[i];
 100               if (sym->name != NULL
 101                   && wanted[0] == sym->name[0]
 102                   && strcmp (wanted + 1, sym->name + 1) == 0)
 103                 {
 104                   ret = 1;
 105                   break;
 106                 }
 107             }
 108         }
 109     }
 110
 111   xfree (symbol_table);
 112   return ret;
 113 }
 114
 115 static enum gdb_osabi
 116 i386_dicos_osabi_sniffer (bfd *abfd)
 117 {
 118   char *target_name = bfd_get_target (abfd);
 119
 120   /* DICOS debug info files don't have a .note.ABI-tag marker or
 121      something similar.  We do know there's always a "header" section
 122      of 36 bytes, and there's always a "Dicos_loadModuleInfo" symbol
 123      defined.  Look for the section first, as that should be
 124      cheaper.  */
 125   if (strcmp (target_name, "elf32-i386") == 0)
 126     {
 127       asection *section = bfd_get_section_by_name (abfd, "header");
 128       if (section
 129           && bfd_section_size (abfd, section) == 36
 130           && i386_dicos_bfd_has_symbol_p (abfd, "Dicos_loadModuleInfo"))
 131         return GDB_OSABI_DICOS;
 132     }
 133
 134   return GDB_OSABI_UNKNOWN;
 135 }
 136
 137 /* Provide a prototype to silence -Wmissing-prototypes.  */
 138 void _initialize_i386_dicos_tdep (void);
 139
 140 void
 141 _initialize_i386_dicos_tdep (void)
 142 {
 143   gdbarch_register_osabi_sniffer (bfd_arch_i386, bfd_target_elf_flavour,
 144                                   i386_dicos_osabi_sniffer);
 145
 146   gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_DICOS,
 147                           i386_dicos_init_abi);
 148 }