Subversion Repositories openrisc_2011-10-31

/* Dynamic architecture support for GDB, the GNU debugger.

   Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,

   2008, 2009, 2010 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"

#include "arch-utils.h"

#include "buildsym.h"

#include "gdbcmd.h"

#include "inferior.h"           /* enum CALL_DUMMY_LOCATION et.al. */

#include "gdb_string.h"

#include "regcache.h"

#include "gdb_assert.h"

#include "sim-regno.h"

#include "gdbcore.h"

#include "osabi.h"

#include "target-descriptions.h"

#include "objfiles.h"

#include "version.h"

#include "floatformat.h"

struct displaced_step_closure *

simple_displaced_step_copy_insn (struct gdbarch *gdbarch,

                                 CORE_ADDR from, CORE_ADDR to,

                                 struct regcache *regs)

{

  size_t len = gdbarch_max_insn_length (gdbarch);

  gdb_byte *buf = xmalloc (len);

  read_memory (from, buf, len);

  write_memory (to, buf, len);

  if (debug_displaced)

    {

      fprintf_unfiltered (gdb_stdlog, "displaced: copy %s->%s: ",

                          paddress (gdbarch, from), paddress (gdbarch, to));

      displaced_step_dump_bytes (gdb_stdlog, buf, len);

    }

  return (struct displaced_step_closure *) buf;

}

void

simple_displaced_step_free_closure (struct gdbarch *gdbarch,

                                    struct displaced_step_closure *closure)

{

  xfree (closure);

}

int

default_displaced_step_hw_singlestep (struct gdbarch *gdbarch,

                                      struct displaced_step_closure *closure)

{

  return !gdbarch_software_single_step_p (gdbarch);

}

CORE_ADDR

displaced_step_at_entry_point (struct gdbarch *gdbarch)

{

  CORE_ADDR addr;

  int bp_len;

  addr = entry_point_address ();

  /* Inferior calls also use the entry point as a breakpoint location.

     We don't want displaced stepping to interfere with those

     breakpoints, so leave space.  */

  gdbarch_breakpoint_from_pc (gdbarch, &addr, &bp_len);

  addr += bp_len * 2;

  return addr;

}

int

legacy_register_sim_regno (struct gdbarch *gdbarch, int regnum)

{

  /* Only makes sense to supply raw registers.  */

  gdb_assert (regnum >= 0 && regnum < gdbarch_num_regs (gdbarch));

  /* NOTE: cagney/2002-05-13: The old code did it this way and it is

     suspected that some GDB/SIM combinations may rely on this

     behavour.  The default should be one2one_register_sim_regno

     (below).  */

  if (gdbarch_register_name (gdbarch, regnum) != NULL

      && gdbarch_register_name (gdbarch, regnum)[0] != '\0')

    return regnum;

  else

    return LEGACY_SIM_REGNO_IGNORE;

}

CORE_ADDR

generic_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)

{

  return 0;

}

CORE_ADDR

generic_skip_solib_resolver (struct gdbarch *gdbarch, CORE_ADDR pc)

{

  return 0;

}

int

generic_in_solib_return_trampoline (struct gdbarch *gdbarch,

                                    CORE_ADDR pc, char *name)

{

  return 0;

}

int

generic_in_function_epilogue_p (struct gdbarch *gdbarch, CORE_ADDR pc)

{

  return 0;

}

/* Helper functions for gdbarch_inner_than */

int

core_addr_lessthan (CORE_ADDR lhs, CORE_ADDR rhs)

{

  return (lhs < rhs);

}

int

core_addr_greaterthan (CORE_ADDR lhs, CORE_ADDR rhs)

{

  return (lhs > rhs);

}

/* Misc helper functions for targets. */

CORE_ADDR

core_addr_identity (struct gdbarch *gdbarch, CORE_ADDR addr)

{

  return addr;

}

CORE_ADDR

convert_from_func_ptr_addr_identity (struct gdbarch *gdbarch, CORE_ADDR addr,

                                     struct target_ops *targ)

{

  return addr;

}

int

no_op_reg_to_regnum (struct gdbarch *gdbarch, int reg)

{

  return reg;

}

void

default_elf_make_msymbol_special (asymbol *sym, struct minimal_symbol *msym)

{

  return;

}

void

default_coff_make_msymbol_special (int val, struct minimal_symbol *msym)

{

  return;

}

int

cannot_register_not (struct gdbarch *gdbarch, int regnum)

{

  return 0;

}

/* Legacy version of target_virtual_frame_pointer().  Assumes that

   there is an gdbarch_deprecated_fp_regnum and that it is the same, cooked or

   raw.  */

void

legacy_virtual_frame_pointer (struct gdbarch *gdbarch,

                              CORE_ADDR pc,

                              int *frame_regnum,

                              LONGEST *frame_offset)

{

  /* FIXME: cagney/2002-09-13: This code is used when identifying the

     frame pointer of the current PC.  It is assuming that a single

     register and an offset can determine this.  I think it should

     instead generate a byte code expression as that would work better

     with things like Dwarf2's CFI.  */

  if (gdbarch_deprecated_fp_regnum (gdbarch) >= 0

      && gdbarch_deprecated_fp_regnum (gdbarch)

           < gdbarch_num_regs (gdbarch))

    *frame_regnum = gdbarch_deprecated_fp_regnum (gdbarch);

  else if (gdbarch_sp_regnum (gdbarch) >= 0

           && gdbarch_sp_regnum (gdbarch)

                < gdbarch_num_regs (gdbarch))

    *frame_regnum = gdbarch_sp_regnum (gdbarch);

  else

    /* Should this be an internal error?  I guess so, it is reflecting

       an architectural limitation in the current design.  */

    internal_error (__FILE__, __LINE__, _("No virtual frame pointer available"));

  *frame_offset = 0;

}

int

generic_convert_register_p (struct gdbarch *gdbarch, int regnum,

                            struct type *type)

{

  return 0;

}

int

default_stabs_argument_has_addr (struct gdbarch *gdbarch, struct type *type)

{

  return 0;

}

int

generic_instruction_nullified (struct gdbarch *gdbarch,

                               struct regcache *regcache)

{

  return 0;

}

int

default_remote_register_number (struct gdbarch *gdbarch,

                                int regno)

{

  return regno;

}

/* Functions to manipulate the endianness of the target.  */

static int target_byte_order_user = BFD_ENDIAN_UNKNOWN;

static const char endian_big[] = "big";

static const char endian_little[] = "little";

static const char endian_auto[] = "auto";

static const char *endian_enum[] =

{

  endian_big,

  endian_little,

  endian_auto,

  NULL,

};

static const char *set_endian_string;

enum bfd_endian

selected_byte_order (void)

{

  return target_byte_order_user;

}

/* Called by ``show endian''.  */

static void

show_endian (struct ui_file *file, int from_tty, struct cmd_list_element *c,

             const char *value)

{

  if (target_byte_order_user == BFD_ENDIAN_UNKNOWN)

    if (gdbarch_byte_order (get_current_arch ()) == BFD_ENDIAN_BIG)

      fprintf_unfiltered (file, _("The target endianness is set automatically "

                                  "(currently big endian)\n"));

    else

      fprintf_unfiltered (file, _("The target endianness is set automatically "

                           "(currently little endian)\n"));

  else

    if (target_byte_order_user == BFD_ENDIAN_BIG)

      fprintf_unfiltered (file,

                          _("The target is assumed to be big endian\n"));

    else

      fprintf_unfiltered (file,

                          _("The target is assumed to be little endian\n"));

}

static void

set_endian (char *ignore_args, int from_tty, struct cmd_list_element *c)

{

  struct gdbarch_info info;

  gdbarch_info_init (&info);

  if (set_endian_string == endian_auto)

    {

      target_byte_order_user = BFD_ENDIAN_UNKNOWN;

      if (! gdbarch_update_p (info))

        internal_error (__FILE__, __LINE__,

                        _("set_endian: architecture update failed"));

    }

  else if (set_endian_string == endian_little)

    {

      info.byte_order = BFD_ENDIAN_LITTLE;

      if (! gdbarch_update_p (info))

        printf_unfiltered (_("Little endian target not supported by GDB\n"));

      else

        target_byte_order_user = BFD_ENDIAN_LITTLE;

    }

  else if (set_endian_string == endian_big)

    {

      info.byte_order = BFD_ENDIAN_BIG;

      if (! gdbarch_update_p (info))

        printf_unfiltered (_("Big endian target not supported by GDB\n"));

      else

        target_byte_order_user = BFD_ENDIAN_BIG;

    }

  else

    internal_error (__FILE__, __LINE__,

                    _("set_endian: bad value"));

  show_endian (gdb_stdout, from_tty, NULL, NULL);

}

/* Given SELECTED, a currently selected BFD architecture, and

   TARGET_DESC, the current target description, return what

   architecture to use.

   SELECTED may be NULL, in which case we return the architecture

   associated with TARGET_DESC.  If SELECTED specifies a variant

   of the architecture associtated with TARGET_DESC, return the

   more specific of the two.

   If SELECTED is a different architecture, but it is accepted as

   compatible by the target, we can use the target architecture.

   If SELECTED is obviously incompatible, warn the user.  */

static const struct bfd_arch_info *

choose_architecture_for_target (const struct target_desc *target_desc,

                                const struct bfd_arch_info *selected)

{

  const struct bfd_arch_info *from_target = tdesc_architecture (target_desc);

  const struct bfd_arch_info *compat1, *compat2;

  if (selected == NULL)

    return from_target;

  if (from_target == NULL)

    return selected;

  /* struct bfd_arch_info objects are singletons: that is, there's

     supposed to be exactly one instance for a given machine.  So you

     can tell whether two are equivalent by comparing pointers.  */

  if (from_target == selected)

    return selected;

  /* BFD's 'A->compatible (A, B)' functions return zero if A and B are

     incompatible.  But if they are compatible, it returns the 'more

     featureful' of the two arches.  That is, if A can run code

     written for B, but B can't run code written for A, then it'll

     return A.

     Some targets (e.g. MIPS as of 2006-12-04) don't fully

     implement this, instead always returning NULL or the first

     argument.  We detect that case by checking both directions.  */

  compat1 = selected->compatible (selected, from_target);

  compat2 = from_target->compatible (from_target, selected);

  if (compat1 == NULL && compat2 == NULL)

    {

      /* BFD considers the architectures incompatible.  Check our target

         description whether it accepts SELECTED as compatible anyway.  */

      if (tdesc_compatible_p (target_desc, selected))

        return from_target;

      warning (_("Selected architecture %s is not compatible "

                 "with reported target architecture %s"),

               selected->printable_name, from_target->printable_name);

      return selected;

    }

  if (compat1 == NULL)

    return compat2;

  if (compat2 == NULL)

    return compat1;

  if (compat1 == compat2)

    return compat1;

  /* If the two didn't match, but one of them was a default architecture,

     assume the more specific one is correct.  This handles the case

     where an executable or target description just says "mips", but

     the other knows which MIPS variant.  */

  if (compat1->the_default)

    return compat2;

  if (compat2->the_default)

    return compat1;

  /* We have no idea which one is better.  This is a bug, but not

     a critical problem; warn the user.  */

  warning (_("Selected architecture %s is ambiguous with "

             "reported target architecture %s"),

           selected->printable_name, from_target->printable_name);

  return selected;

}

/* Functions to manipulate the architecture of the target */

enum set_arch { set_arch_auto, set_arch_manual };

static const struct bfd_arch_info *target_architecture_user;

static const char *set_architecture_string;

const char *

selected_architecture_name (void)

{

  if (target_architecture_user == NULL)

    return NULL;

  else

    return set_architecture_string;

}

/* Called if the user enters ``show architecture'' without an

   argument. */

static void

show_architecture (struct ui_file *file, int from_tty,

                   struct cmd_list_element *c, const char *value)

{

  if (target_architecture_user == NULL)

    fprintf_filtered (file, _("\

The target architecture is set automatically (currently %s)\n"),

                gdbarch_bfd_arch_info (get_current_arch ())->printable_name);

  else

    fprintf_filtered (file, _("\

The target architecture is assumed to be %s\n"), set_architecture_string);

}

/* Called if the user enters ``set architecture'' with or without an

   argument. */

static void

set_architecture (char *ignore_args, int from_tty, struct cmd_list_element *c)

{

  struct gdbarch_info info;

  gdbarch_info_init (&info);

  if (strcmp (set_architecture_string, "auto") == 0)

    {

      target_architecture_user = NULL;

      if (!gdbarch_update_p (info))

        internal_error (__FILE__, __LINE__,

                        _("could not select an architecture automatically"));

    }

  else

    {

      info.bfd_arch_info = bfd_scan_arch (set_architecture_string);

      if (info.bfd_arch_info == NULL)

        internal_error (__FILE__, __LINE__,

                        _("set_architecture: bfd_scan_arch failed"));

      if (gdbarch_update_p (info))

        target_architecture_user = info.bfd_arch_info;

      else

        printf_unfiltered (_("Architecture `%s' not recognized.\n"),

                           set_architecture_string);

    }

  show_architecture (gdb_stdout, from_tty, NULL, NULL);

}

/* Try to select a global architecture that matches "info".  Return

   non-zero if the attempt succeds.  */

int

gdbarch_update_p (struct gdbarch_info info)

{

  struct gdbarch *new_gdbarch;

  /* Check for the current file.  */

  if (info.abfd == NULL)

    info.abfd = exec_bfd;

  if (info.abfd == NULL)

    info.abfd = core_bfd;

  /* Check for the current target description.  */

  if (info.target_desc == NULL)

    info.target_desc = target_current_description ();

  new_gdbarch = gdbarch_find_by_info (info);

  /* If there no architecture by that name, reject the request.  */

  if (new_gdbarch == NULL)

    {

      if (gdbarch_debug)

        fprintf_unfiltered (gdb_stdlog, "gdbarch_update_p: "

                            "Architecture not found\n");

      return 0;

    }

  /* If it is the same old architecture, accept the request (but don't

     swap anything).  */

  if (new_gdbarch == target_gdbarch)

    {

      if (gdbarch_debug)

        fprintf_unfiltered (gdb_stdlog, "gdbarch_update_p: "

                            "Architecture %s (%s) unchanged\n",

                            host_address_to_string (new_gdbarch),

                            gdbarch_bfd_arch_info (new_gdbarch)->printable_name);

      return 1;

    }

  /* It's a new architecture, swap it in.  */

  if (gdbarch_debug)

    fprintf_unfiltered (gdb_stdlog, "gdbarch_update_p: "

                        "New architecture %s (%s) selected\n",

                        host_address_to_string (new_gdbarch),

                        gdbarch_bfd_arch_info (new_gdbarch)->printable_name);

  deprecated_target_gdbarch_select_hack (new_gdbarch);

  return 1;

}

/* Return the architecture for ABFD.  If no suitable architecture

   could be find, return NULL.  */

struct gdbarch *

gdbarch_from_bfd (bfd *abfd)

{

  struct gdbarch_info info;

  gdbarch_info_init (&info);

  info.abfd = abfd;

  return gdbarch_find_by_info (info);

}

/* Set the dynamic target-system-dependent parameters (architecture,

   byte-order) using information found in the BFD */

void

set_gdbarch_from_file (bfd *abfd)

{

  struct gdbarch_info info;

  struct gdbarch *gdbarch;

  gdbarch_info_init (&info);

  info.abfd = abfd;

  info.target_desc = target_current_description ();

  gdbarch = gdbarch_find_by_info (info);

  if (gdbarch == NULL)

    error (_("Architecture of file not recognized."));

  deprecated_target_gdbarch_select_hack (gdbarch);

}

/* Initialize the current architecture.  Update the ``set

   architecture'' command so that it specifies a list of valid

   architectures.  */

#ifdef DEFAULT_BFD_ARCH

extern const bfd_arch_info_type DEFAULT_BFD_ARCH;

static const bfd_arch_info_type *default_bfd_arch = &DEFAULT_BFD_ARCH;

#else

static const bfd_arch_info_type *default_bfd_arch;

#endif

#ifdef DEFAULT_BFD_VEC

extern const bfd_target DEFAULT_BFD_VEC;

static const bfd_target *default_bfd_vec = &DEFAULT_BFD_VEC;

#else

static const bfd_target *default_bfd_vec;

#endif

static int default_byte_order = BFD_ENDIAN_UNKNOWN;

void

initialize_current_architecture (void)

{

  const char **arches = gdbarch_printable_names ();

  /* determine a default architecture and byte order. */

  struct gdbarch_info info;

  gdbarch_info_init (&info);

  /* Find a default architecture. */

  if (default_bfd_arch == NULL)

    {

      /* Choose the architecture by taking the first one

         alphabetically. */

      const char *chosen = arches[0];

      const char **arch;

      for (arch = arches; *arch != NULL; arch++)

        {

          if (strcmp (*arch, chosen) < 0)

            chosen = *arch;

        }

      if (chosen == NULL)

        internal_error (__FILE__, __LINE__,

                        _("initialize_current_architecture: No arch"));

      default_bfd_arch = bfd_scan_arch (chosen);

      if (default_bfd_arch == NULL)

        internal_error (__FILE__, __LINE__,

                        _("initialize_current_architecture: Arch not found"));

    }

  info.bfd_arch_info = default_bfd_arch;

  /* Take several guesses at a byte order.  */

  if (default_byte_order == BFD_ENDIAN_UNKNOWN

      && default_bfd_vec != NULL)

    {

      /* Extract BFD's default vector's byte order. */

      switch (default_bfd_vec->byteorder)

        {

        case BFD_ENDIAN_BIG:

          default_byte_order = BFD_ENDIAN_BIG;

          break;

        case BFD_ENDIAN_LITTLE:

          default_byte_order = BFD_ENDIAN_LITTLE;

          break;

        default:

          break;

        }

    }

  if (default_byte_order == BFD_ENDIAN_UNKNOWN)

    {

      /* look for ``*el-*'' in the target name. */

      const char *chp;

      chp = strchr (target_name, '-');

      if (chp != NULL

          && chp - 2 >= target_name

          && strncmp (chp - 2, "el", 2) == 0)

        default_byte_order = BFD_ENDIAN_LITTLE;

    }

  if (default_byte_order == BFD_ENDIAN_UNKNOWN)

    {

      /* Wire it to big-endian!!! */

      default_byte_order = BFD_ENDIAN_BIG;

    }

  info.byte_order = default_byte_order;

  info.byte_order_for_code = info.byte_order;

  if (! gdbarch_update_p (info))

    internal_error (__FILE__, __LINE__,

                    _("initialize_current_architecture: Selection of "

                      "initial architecture failed"));

  /* Create the ``set architecture'' command appending ``auto'' to the

     list of architectures. */

  {

    struct cmd_list_element *c;

    /* Append ``auto''. */

    int nr;

    for (nr = 0; arches[nr] != NULL; nr++);

    arches = xrealloc (arches, sizeof (char*) * (nr + 2));

    arches[nr + 0] = "auto";

    arches[nr + 1] = NULL;

    add_setshow_enum_cmd ("architecture", class_support,

                          arches, &set_architecture_string, _("\

Set architecture of target."), _("\

Show architecture of target."), NULL,

                          set_architecture, show_architecture,

                          &setlist, &showlist);

    add_alias_cmd ("processor", "architecture", class_support, 1, &setlist);

  }

}

/* Initialize a gdbarch info to values that will be automatically

   overridden.  Note: Originally, this ``struct info'' was initialized

   using memset(0).  Unfortunately, that ran into problems, namely

   BFD_ENDIAN_BIG is zero.  An explicit initialization function that

   can explicitly set each field to a well defined value is used.  */

void

gdbarch_info_init (struct gdbarch_info *info)

{

  memset (info, 0, sizeof (struct gdbarch_info));

  info->byte_order = BFD_ENDIAN_UNKNOWN;

  info->byte_order_for_code = info->byte_order;

  info->osabi = GDB_OSABI_UNINITIALIZED;

}

/* Similar to init, but this time fill in the blanks.  Information is

   obtained from the global "set ..." options and explicitly

   initialized INFO fields.  */

void

gdbarch_info_fill (struct gdbarch_info *info)

{

  /* "(gdb) set architecture ...".  */

  if (info->bfd_arch_info == NULL

      && target_architecture_user)

    info->bfd_arch_info = target_architecture_user;

  /* From the file.  */

  if (info->bfd_arch_info == NULL

      && info->abfd != NULL

      && bfd_get_arch (info->abfd) != bfd_arch_unknown

      && bfd_get_arch (info->abfd) != bfd_arch_obscure)

    info->bfd_arch_info = bfd_get_arch_info (info->abfd);

  /* From the target.  */

  if (info->target_desc != NULL)

    info->bfd_arch_info = choose_architecture_for_target

                           (info->target_desc, info->bfd_arch_info);

  /* From the default.  */

  if (info->bfd_arch_info == NULL)

    info->bfd_arch_info = default_bfd_arch;