gdb/i386-dicos-tdep.c

   1 /* Target-dependent code for DICOS running on i386's, for GDB.
   2
   3    Copyright (C) 2008 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_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp)
  29 {
  30   /* Having a call dummy on the stack requires a gdbarch_frame_align
  31      method to align the breakpoint instruction in the stack.
  32      Strictly speaking, we could just return SP pristine on x86.  But,
  33      as long as we're providing a frame align method, might as well
  34      align for efficiency.  */
  35   return sp & -(CORE_ADDR)16;
  36 }
  37
  38 static void
  39 i386_dicos_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
  40 {
  41   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  42
  43   set_solib_ops (gdbarch, &solib_target_so_ops);
  44
  45   /* There's no (standard definition of) entry point or a guaranteed
  46      text location we could find with a symbol where to place the call
  47      dummy, so we put it on the stack.  */
  48   set_gdbarch_call_dummy_location (gdbarch, ON_STACK);
  49   set_gdbarch_frame_align (gdbarch, i386_dicos_frame_align);
  50 }
  51
  52 /* Look in the elf symbol table of ABFD for a symbol named WANTED.
  53    Return true if found.  */
  54 static int
  55 i386_dicos_bfd_has_symbol_p (bfd *abfd, const char *wanted)
  56 {
  57   long storage_needed;
  58   int ret = 0;
  59   asymbol **symbol_table = NULL;
  60
  61   storage_needed = bfd_get_symtab_upper_bound (abfd);
  62   if (storage_needed < 0)
  63     {
  64       warning (_("Can't read elf symbols from %s: %s"), bfd_get_filename (abfd),
  65                bfd_errmsg (bfd_get_error ()));
  66       return 0;
  67     }
  68
  69   if (storage_needed > 0)
  70     {
  71       long i, symcount;
  72
  73       symbol_table = xmalloc (storage_needed);
  74       symcount = bfd_canonicalize_symtab (abfd, symbol_table);
  75
  76       if (symcount < 0)
  77         warning (_("Can't read elf symbols from %s: %s"),
  78                  bfd_get_filename (abfd),
  79                  bfd_errmsg (bfd_get_error ()));
  80       else
  81         {
  82           for (i = 0; i < symcount; i++)
  83             {
  84               asymbol *sym = symbol_table[i];
  85               if (sym->name != NULL
  86                   && wanted[0] == sym->name[0]
  87                   && strcmp (wanted + 1, sym->name + 1) == 0)
  88                 {
  89                   ret = 1;
  90                   break;
  91                 }
  92             }
  93         }
  94     }
  95
  96   xfree (symbol_table);
  97   return ret;
  98 }
  99
 100 static enum gdb_osabi
 101 i386_dicos_osabi_sniffer (bfd *abfd)
 102 {
 103   char *target_name = bfd_get_target (abfd);
 104
 105   /* DICOS debug info files don't have a .note.ABI-tag marker or
 106      something similar.  We do know there's always a "header" section
 107      of 36 bytes, and there's always a "Dicos_loadModuleInfo" symbol
 108      defined.  Look for the section first, as that should be
 109      cheaper.  */
 110   if (strcmp (target_name, "elf32-i386") == 0)
 111     {
 112       asection *section = bfd_get_section_by_name (abfd, "header");
 113       if (section
 114           && bfd_section_size (abfd, section) == 36
 115           && i386_dicos_bfd_has_symbol_p (abfd, "Dicos_loadModuleInfo"))
 116         return GDB_OSABI_DICOS;
 117     }
 118
 119   return GDB_OSABI_UNKNOWN;
 120 }
 121
 122 /* Provide a prototype to silence -Wmissing-prototypes.  */
 123 void _initialize_i386_dicos_tdep (void);
 124
 125 void
 126 _initialize_i386_dicos_tdep (void)
 127 {
 128   gdbarch_register_osabi_sniffer (bfd_arch_i386, bfd_target_elf_flavour,
 129                                   i386_dicos_osabi_sniffer);
 130
 131   gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_DICOS,
 132                           i386_dicos_init_abi);
 133 }