gdb/i386bsd-tdep.c

   1 /* Target-dependent code for i386 BSD's.
   2    Copyright 2001, 2002, 2003 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include "defs.h"
  22 #include "arch-utils.h"
  23 #include "frame.h"
  24 #include "gdbcore.h"
  25 #include "regcache.h"
  26 #include "osabi.h"
  27
  28 #include "gdb_string.h"
  29
  30 #include "i386-tdep.h"
  31
  32 /* Support for signal handlers.  */
  33
  34 /* Return whether PC is in a BSD sigtramp routine.  */
  35
  36 static int
  37 i386bsd_pc_in_sigtramp (CORE_ADDR pc, char *name)
  38 {
  39   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
  40
  41   return (pc >= tdep->sigtramp_start && pc < tdep->sigtramp_end);
  42 }
  43
  44 /* Assuming FRAME is for a BSD sigtramp routine, return the address of
  45    the associated sigcontext structure.
  46
  47    Note: This function is used for Solaris 2 too, so don't make it
  48    static.  */
  49
  50 CORE_ADDR
  51 i386bsd_sigcontext_addr (struct frame_info *frame)
  52 {
  53   if (frame->next)
  54     /* If this isn't the top frame, the next frame must be for the
  55        signal handler itself.  A pointer to the sigcontext structure
  56        is passed as the third argument to the signal handler.  */
  57     return read_memory_unsigned_integer (frame->next->frame + 16, 4);
  58
  59   /* This is the top frame.  We'll have to find the address of the
  60      sigcontext structure by looking at the stack pointer.  */
  61   return read_memory_unsigned_integer (read_register (SP_REGNUM) + 8, 4);
  62 }
  63
  64 /* Return the start address of the sigtramp routine.  */
  65
  66 CORE_ADDR
  67 i386bsd_sigtramp_start (CORE_ADDR pc)
  68 {
  69   return gdbarch_tdep (current_gdbarch)->sigtramp_start;
  70 }
  71
  72 /* Return the end address of the sigtramp routine.  */
  73
  74 CORE_ADDR
  75 i386bsd_sigtramp_end (CORE_ADDR pc)
  76 {
  77   return gdbarch_tdep (current_gdbarch)->sigtramp_end;
  78 }
  79 \f
  80
  81 /* Support for shared libraries.  */
  82
  83 /* Return non-zero if we are in a shared library trampoline code stub.  */
  84
  85 int
  86 i386bsd_aout_in_solib_call_trampoline (CORE_ADDR pc, char *name)
  87 {
  88   return (name && !strcmp (name, "_DYNAMIC"));
  89 }
  90
  91 /* Traditional BSD (4.3 BSD, still used for BSDI and 386BSD).  */
  92
  93 /* From <machine/signal.h>.  */
  94 int i386bsd_sc_pc_offset = 20;
  95 int i386bsd_sc_sp_offset = 8;
  96
  97 void
  98 i386bsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
  99 {
 100   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 101
 102   set_gdbarch_pc_in_sigtramp (gdbarch, i386bsd_pc_in_sigtramp);
 103
 104   /* Allow the recognition of sigtramps as a function named <sigtramp>.  */
 105   set_gdbarch_sigtramp_start (gdbarch, i386bsd_sigtramp_start);
 106   set_gdbarch_sigtramp_end (gdbarch, i386bsd_sigtramp_end);
 107
 108   /* Assume SunOS-style shared libraries.  */
 109   set_gdbarch_in_solib_call_trampoline (gdbarch,
 110                                         i386bsd_aout_in_solib_call_trampoline);
 111
 112   tdep->jb_pc_offset = 0;
 113
 114   tdep->sigtramp_start = 0xfdbfdfc0;
 115   tdep->sigtramp_end = 0xfdbfe000;
 116   tdep->sigcontext_addr = i386bsd_sigcontext_addr;
 117   tdep->sc_pc_offset = i386bsd_sc_pc_offset;
 118   tdep->sc_sp_offset = i386bsd_sc_sp_offset;
 119 }
 120
 121 /* FreeBSD 3.0-RELEASE or later.  */
 122
 123 CORE_ADDR i386fbsd_sigtramp_start = 0xbfbfdf20;
 124 CORE_ADDR i386fbsd_sigtramp_end = 0xbfbfdff0;
 125
 126 static void
 127 i386fbsdaout_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 128 {
 129   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 130
 131   /* Obviously FreeBSD is BSD-based.  */
 132   i386bsd_init_abi (info, gdbarch);
 133
 134   /* FreeBSD uses -freg-struct-return by default.  */
 135   tdep->struct_return = reg_struct_return;
 136
 137   /* FreeBSD uses a different memory layout.  */
 138   tdep->sigtramp_start = i386fbsd_sigtramp_start;
 139   tdep->sigtramp_end = i386fbsd_sigtramp_end;
 140 }
 141
 142 static void
 143 i386fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 144 {
 145   /* It's almost identical to FreeBSD a.out.  */
 146   i386fbsdaout_init_abi (info, gdbarch);
 147
 148   /* Except that it uses ELF.  */
 149   i386_elf_init_abi (info, gdbarch);
 150
 151   /* FreeBSD ELF uses SVR4-style shared libraries.  */
 152   set_gdbarch_in_solib_call_trampoline (gdbarch,
 153                                         generic_in_solib_call_trampoline);
 154 }
 155
 156 /* FreeBSD 4.0-RELEASE or later.  */
 157
 158 /* From <machine/signal.h>.  */
 159 int i386fbsd4_sc_pc_offset = 76;
 160 int i386fbsd4_sc_sp_offset = 88;
 161
 162 static void
 163 i386fbsd4_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 164 {
 165   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 166
 167   /* Inherit stuff from older releases.  We assume that FreeBSD
 168      4.0-RELEASE always uses ELF.  */
 169   i386fbsd_init_abi (info, gdbarch);
 170
 171   /* FreeBSD 4.0 introduced a new `struct sigcontext'.  */
 172   tdep->sc_pc_offset = i386fbsd4_sc_pc_offset;
 173   tdep->sc_sp_offset = i386fbsd4_sc_sp_offset;
 174 }
 175
 176 \f
 177 static enum gdb_osabi
 178 i386bsd_aout_osabi_sniffer (bfd *abfd)
 179 {
 180   if (strcmp (bfd_get_target (abfd), "a.out-i386-netbsd") == 0)
 181     return GDB_OSABI_NETBSD_AOUT;
 182
 183   if (strcmp (bfd_get_target (abfd), "a.out-i386-freebsd") == 0)
 184     return GDB_OSABI_FREEBSD_AOUT;
 185
 186   return GDB_OSABI_UNKNOWN;
 187 }
 188
 189 \f
 190 /* Provide a prototype to silence -Wmissing-prototypes.  */
 191 void _initialize_i386bsd_tdep (void);
 192
 193 void
 194 _initialize_i386bsd_tdep (void)
 195 {
 196   gdbarch_register_osabi_sniffer (bfd_arch_i386, bfd_target_aout_flavour,
 197                                   i386bsd_aout_osabi_sniffer);
 198
 199   gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_FREEBSD_AOUT,
 200                           i386fbsdaout_init_abi);
 201   gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_FREEBSD_ELF,
 202                           i386fbsd4_init_abi);
 203 }