gdb/arch-utils.c

   1 /* Dynamic architecture support for GDB, the GNU debugger.
   2
   3    Copyright (C) 1998-2017 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
  22 #include "arch-utils.h"
  23 #include "buildsym.h"
  24 #include "gdbcmd.h"
  25 #include "inferior.h"           /* enum CALL_DUMMY_LOCATION et al.  */
  26 #include "infrun.h"
  27 #include "regcache.h"
  28 #include "sim-regno.h"
  29 #include "gdbcore.h"
  30 #include "osabi.h"
  31 #include "target-descriptions.h"
  32 #include "objfiles.h"
  33 #include "language.h"
  34 #include "symtab.h"
  35
  36 #include "version.h"
  37
  38 #include "floatformat.h"
  39
  40 #include "dis-asm.h"
  41
  42 struct displaced_step_closure *
  43 simple_displaced_step_copy_insn (struct gdbarch *gdbarch,
  44                                  CORE_ADDR from, CORE_ADDR to,
  45                                  struct regcache *regs)
  46 {
  47   size_t len = gdbarch_max_insn_length (gdbarch);
  48   gdb_byte *buf = (gdb_byte *) xmalloc (len);
  49
  50   read_memory (from, buf, len);
  51   write_memory (to, buf, len);
  52
  53   if (debug_displaced)
  54     {
  55       fprintf_unfiltered (gdb_stdlog, "displaced: copy %s->%s: ",
  56                           paddress (gdbarch, from), paddress (gdbarch, to));
  57       displaced_step_dump_bytes (gdb_stdlog, buf, len);
  58     }
  59
  60   return (struct displaced_step_closure *) buf;
  61 }
  62
  63 int
  64 default_displaced_step_hw_singlestep (struct gdbarch *gdbarch,
  65                                       struct displaced_step_closure *closure)
  66 {
  67   return !gdbarch_software_single_step_p (gdbarch);
  68 }
  69
  70 CORE_ADDR
  71 displaced_step_at_entry_point (struct gdbarch *gdbarch)
  72 {
  73   CORE_ADDR addr;
  74   int bp_len;
  75
  76   addr = entry_point_address ();
  77
  78   /* Inferior calls also use the entry point as a breakpoint location.
  79      We don't want displaced stepping to interfere with those
  80      breakpoints, so leave space.  */
  81   gdbarch_breakpoint_from_pc (gdbarch, &addr, &bp_len);
  82   addr += bp_len * 2;
  83
  84   return addr;
  85 }
  86
  87 int
  88 legacy_register_sim_regno (struct gdbarch *gdbarch, int regnum)
  89 {
  90   /* Only makes sense to supply raw registers.  */
  91   gdb_assert (regnum >= 0 && regnum < gdbarch_num_regs (gdbarch));
  92   /* NOTE: cagney/2002-05-13: The old code did it this way and it is
  93      suspected that some GDB/SIM combinations may rely on this
  94      behavour.  The default should be one2one_register_sim_regno
  95      (below).  */
  96   if (gdbarch_register_name (gdbarch, regnum) != NULL
  97       && gdbarch_register_name (gdbarch, regnum)[0] != '\0')
  98     return regnum;
  99   else
 100     return LEGACY_SIM_REGNO_IGNORE;
 101 }
 102
 103 CORE_ADDR
 104 generic_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
 105 {
 106   return 0;
 107 }
 108
 109 CORE_ADDR
 110 generic_skip_solib_resolver (struct gdbarch *gdbarch, CORE_ADDR pc)
 111 {
 112   return 0;
 113 }
 114
 115 int
 116 generic_in_solib_return_trampoline (struct gdbarch *gdbarch,
 117                                     CORE_ADDR pc, const char *name)
 118 {
 119   return 0;
 120 }
 121
 122 int
 123 generic_stack_frame_destroyed_p (struct gdbarch *gdbarch, CORE_ADDR pc)
 124 {
 125   return 0;
 126 }
 127
 128 int
 129 default_code_of_frame_writable (struct gdbarch *gdbarch,
 130                                 struct frame_info *frame)
 131 {
 132   return 1;
 133 }
 134
 135 /* Helper functions for gdbarch_inner_than */
 136
 137 int
 138 core_addr_lessthan (CORE_ADDR lhs, CORE_ADDR rhs)
 139 {
 140   return (lhs < rhs);
 141 }
 142
 143 int
 144 core_addr_greaterthan (CORE_ADDR lhs, CORE_ADDR rhs)
 145 {
 146   return (lhs > rhs);
 147 }
 148
 149 /* Misc helper functions for targets.  */
 150
 151 CORE_ADDR
 152 core_addr_identity (struct gdbarch *gdbarch, CORE_ADDR addr)
 153 {
 154   return addr;
 155 }
 156
 157 CORE_ADDR
 158 convert_from_func_ptr_addr_identity (struct gdbarch *gdbarch, CORE_ADDR addr,
 159                                      struct target_ops *targ)
 160 {
 161   return addr;
 162 }
 163
 164 int
 165 no_op_reg_to_regnum (struct gdbarch *gdbarch, int reg)
 166 {
 167   return reg;
 168 }
 169
 170 void
 171 default_coff_make_msymbol_special (int val, struct minimal_symbol *msym)
 172 {
 173   return;
 174 }
 175
 176 /* See arch-utils.h.  */
 177
 178 void
 179 default_make_symbol_special (struct symbol *sym, struct objfile *objfile)
 180 {
 181   return;
 182 }
 183
 184 /* See arch-utils.h.  */
 185
 186 CORE_ADDR
 187 default_adjust_dwarf2_addr (CORE_ADDR pc)
 188 {
 189   return pc;
 190 }
 191
 192 /* See arch-utils.h.  */
 193
 194 CORE_ADDR
 195 default_adjust_dwarf2_line (CORE_ADDR addr, int rel)
 196 {
 197   return addr;
 198 }
 199
 200 /* See arch-utils.h.  */
 201
 202 bool
 203 default_execute_dwarf_cfa_vendor_op (struct gdbarch *gdbarch, gdb_byte op,
 204                                      struct dwarf2_frame_state *fs)
 205 {
 206   return false;
 207 }
 208
 209 int
 210 cannot_register_not (struct gdbarch *gdbarch, int regnum)
 211 {
 212   return 0;
 213 }
 214
 215 /* Legacy version of target_virtual_frame_pointer().  Assumes that
 216    there is an gdbarch_deprecated_fp_regnum and that it is the same,
 217    cooked or raw.  */
 218
 219 void
 220 legacy_virtual_frame_pointer (struct gdbarch *gdbarch,
 221                               CORE_ADDR pc,
 222                               int *frame_regnum,
 223                               LONGEST *frame_offset)
 224 {
 225   /* FIXME: cagney/2002-09-13: This code is used when identifying the
 226      frame pointer of the current PC.  It is assuming that a single
 227      register and an offset can determine this.  I think it should
 228      instead generate a byte code expression as that would work better
 229      with things like Dwarf2's CFI.  */
 230   if (gdbarch_deprecated_fp_regnum (gdbarch) >= 0
 231       && gdbarch_deprecated_fp_regnum (gdbarch)
 232            < gdbarch_num_regs (gdbarch))
 233     *frame_regnum = gdbarch_deprecated_fp_regnum (gdbarch);
 234   else if (gdbarch_sp_regnum (gdbarch) >= 0
 235            && gdbarch_sp_regnum (gdbarch)
 236                 < gdbarch_num_regs (gdbarch))
 237     *frame_regnum = gdbarch_sp_regnum (gdbarch);
 238   else
 239     /* Should this be an internal error?  I guess so, it is reflecting
 240        an architectural limitation in the current design.  */
 241     internal_error (__FILE__, __LINE__,
 242                     _("No virtual frame pointer available"));
 243   *frame_offset = 0;
 244 }
 245
 246 /* Return a floating-point format for a floating-point variable of
 247    length LEN in bits.  If non-NULL, NAME is the name of its type.
 248    If no suitable type is found, return NULL.  */
 249
 250 const struct floatformat **
 251 default_floatformat_for_type (struct gdbarch *gdbarch,
 252                               const char *name, int len)
 253 {
 254   const struct floatformat **format = NULL;
 255
 256   if (len == gdbarch_half_bit (gdbarch))
 257     format = gdbarch_half_format (gdbarch);
 258   else if (len == gdbarch_float_bit (gdbarch))
 259     format = gdbarch_float_format (gdbarch);
 260   else if (len == gdbarch_double_bit (gdbarch))
 261     format = gdbarch_double_format (gdbarch);
 262   else if (len == gdbarch_long_double_bit (gdbarch))
 263     format = gdbarch_long_double_format (gdbarch);
 264   /* On i386 the 'long double' type takes 96 bits,
 265      while the real number of used bits is only 80,
 266      both in processor and in memory.
 267      The code below accepts the real bit size.  */
 268   else if (gdbarch_long_double_format (gdbarch) != NULL
 269            && len == gdbarch_long_double_format (gdbarch)[0]->totalsize)
 270     format = gdbarch_long_double_format (gdbarch);
 271
 272   return format;
 273 }
 274 \f
 275 int
 276 generic_convert_register_p (struct gdbarch *gdbarch, int regnum,
 277                             struct type *type)
 278 {
 279   return 0;
 280 }
 281
 282 int
 283 default_stabs_argument_has_addr (struct gdbarch *gdbarch, struct type *type)
 284 {
 285   return 0;
 286 }
 287
 288 int
 289 generic_instruction_nullified (struct gdbarch *gdbarch,
 290                                struct regcache *regcache)
 291 {
 292   return 0;
 293 }
 294
 295 int
 296 default_remote_register_number (struct gdbarch *gdbarch,
 297                                 int regno)
 298 {
 299   return regno;
 300 }
 301
 302 /* See arch-utils.h.  */
 303
 304 int
 305 default_vsyscall_range (struct gdbarch *gdbarch, struct mem_range *range)
 306 {
 307   return 0;
 308 }
 309
 310 \f
 311 /* Functions to manipulate the endianness of the target.  */
 312
 313 static enum bfd_endian target_byte_order_user = BFD_ENDIAN_UNKNOWN;
 314
 315 static const char endian_big[] = "big";
 316 static const char endian_little[] = "little";
 317 static const char endian_auto[] = "auto";
 318 static const char *const endian_enum[] =
 319 {
 320   endian_big,
 321   endian_little,
 322   endian_auto,
 323   NULL,
 324 };
 325 static const char *set_endian_string;
 326
 327 enum bfd_endian
 328 selected_byte_order (void)
 329 {
 330   return target_byte_order_user;
 331 }
 332
 333 /* Called by ``show endian''.  */
 334
 335 static void
 336 show_endian (struct ui_file *file, int from_tty, struct cmd_list_element *c,
 337              const char *value)
 338 {
 339   if (target_byte_order_user == BFD_ENDIAN_UNKNOWN)
 340     if (gdbarch_byte_order (get_current_arch ()) == BFD_ENDIAN_BIG)
 341       fprintf_unfiltered (file, _("The target endianness is set automatically "
 342                                   "(currently big endian)\n"));
 343     else
 344       fprintf_unfiltered (file, _("The target endianness is set automatically "
 345                                   "(currently little endian)\n"));
 346   else
 347     if (target_byte_order_user == BFD_ENDIAN_BIG)
 348       fprintf_unfiltered (file,
 349                           _("The target is assumed to be big endian\n"));
 350     else
 351       fprintf_unfiltered (file,
 352                           _("The target is assumed to be little endian\n"));
 353 }
 354
 355 static void
 356 set_endian (char *ignore_args, int from_tty, struct cmd_list_element *c)
 357 {
 358   struct gdbarch_info info;
 359
 360   gdbarch_info_init (&info);
 361
 362   if (set_endian_string == endian_auto)
 363     {
 364       target_byte_order_user = BFD_ENDIAN_UNKNOWN;
 365       if (! gdbarch_update_p (info))
 366         internal_error (__FILE__, __LINE__,
 367                         _("set_endian: architecture update failed"));
 368     }
 369   else if (set_endian_string == endian_little)
 370     {
 371       info.byte_order = BFD_ENDIAN_LITTLE;
 372       if (! gdbarch_update_p (info))
 373         printf_unfiltered (_("Little endian target not supported by GDB\n"));
 374       else
 375         target_byte_order_user = BFD_ENDIAN_LITTLE;
 376     }
 377   else if (set_endian_string == endian_big)
 378     {
 379       info.byte_order = BFD_ENDIAN_BIG;
 380       if (! gdbarch_update_p (info))
 381         printf_unfiltered (_("Big endian target not supported by GDB\n"));
 382       else
 383         target_byte_order_user = BFD_ENDIAN_BIG;
 384     }
 385   else
 386     internal_error (__FILE__, __LINE__,
 387                     _("set_endian: bad value"));
 388
 389   show_endian (gdb_stdout, from_tty, NULL, NULL);
 390 }
 391
 392 /* Given SELECTED, a currently selected BFD architecture, and
 393    TARGET_DESC, the current target description, return what
 394    architecture to use.
 395
 396    SELECTED may be NULL, in which case we return the architecture
 397    associated with TARGET_DESC.  If SELECTED specifies a variant
 398    of the architecture associtated with TARGET_DESC, return the
 399    more specific of the two.
 400
 401    If SELECTED is a different architecture, but it is accepted as
 402    compatible by the target, we can use the target architecture.
 403
 404    If SELECTED is obviously incompatible, warn the user.  */
 405
 406 static const struct bfd_arch_info *
 407 choose_architecture_for_target (const struct target_desc *target_desc,
 408                                 const struct bfd_arch_info *selected)
 409 {
 410   const struct bfd_arch_info *from_target = tdesc_architecture (target_desc);
 411   const struct bfd_arch_info *compat1, *compat2;
 412
 413   if (selected == NULL)
 414     return from_target;
 415
 416   if (from_target == NULL)
 417     return selected;
 418
 419   /* struct bfd_arch_info objects are singletons: that is, there's
 420      supposed to be exactly one instance for a given machine.  So you
 421      can tell whether two are equivalent by comparing pointers.  */
 422   if (from_target == selected)
 423     return selected;
 424
 425   /* BFD's 'A->compatible (A, B)' functions return zero if A and B are
 426      incompatible.  But if they are compatible, it returns the 'more
 427      featureful' of the two arches.  That is, if A can run code
 428      written for B, but B can't run code written for A, then it'll
 429      return A.
 430
 431      Some targets (e.g. MIPS as of 2006-12-04) don't fully
 432      implement this, instead always returning NULL or the first
 433      argument.  We detect that case by checking both directions.  */
 434
 435   compat1 = selected->compatible (selected, from_target);
 436   compat2 = from_target->compatible (from_target, selected);
 437
 438   if (compat1 == NULL && compat2 == NULL)
 439     {
 440       /* BFD considers the architectures incompatible.  Check our
 441          target description whether it accepts SELECTED as compatible
 442          anyway.  */
 443       if (tdesc_compatible_p (target_desc, selected))
 444         return from_target;
 445
 446       warning (_("Selected architecture %s is not compatible "
 447                  "with reported target architecture %s"),
 448                selected->printable_name, from_target->printable_name);
 449       return selected;
 450     }
 451
 452   if (compat1 == NULL)
 453     return compat2;
 454   if (compat2 == NULL)
 455     return compat1;
 456   if (compat1 == compat2)
 457     return compat1;
 458
 459   /* If the two didn't match, but one of them was a default
 460      architecture, assume the more specific one is correct.  This
 461      handles the case where an executable or target description just
 462      says "mips", but the other knows which MIPS variant.  */
 463   if (compat1->the_default)
 464     return compat2;
 465   if (compat2->the_default)
 466     return compat1;
 467
 468   /* We have no idea which one is better.  This is a bug, but not
 469      a critical problem; warn the user.  */
 470   warning (_("Selected architecture %s is ambiguous with "
 471              "reported target architecture %s"),
 472            selected->printable_name, from_target->printable_name);
 473   return selected;
 474 }
 475
 476 /* Functions to manipulate the architecture of the target.  */
 477
 478 enum set_arch { set_arch_auto, set_arch_manual };
 479
 480 static const struct bfd_arch_info *target_architecture_user;
 481
 482 static const char *set_architecture_string;
 483
 484 const char *
 485 selected_architecture_name (void)
 486 {
 487   if (target_architecture_user == NULL)
 488     return NULL;
 489   else
 490     return set_architecture_string;
 491 }
 492
 493 /* Called if the user enters ``show architecture'' without an
 494    argument.  */
 495
 496 static void
 497 show_architecture (struct ui_file *file, int from_tty,
 498                    struct cmd_list_element *c, const char *value)
 499 {
 500   if (target_architecture_user == NULL)
 501     fprintf_filtered (file, _("The target architecture is set "
 502                               "automatically (currently %s)\n"),
 503                       gdbarch_bfd_arch_info (get_current_arch ())->printable_name);
 504   else
 505     fprintf_filtered (file, _("The target architecture is assumed to be %s\n"),
 506                       set_architecture_string);
 507 }
 508
 509
 510 /* Called if the user enters ``set architecture'' with or without an
 511    argument.  */
 512
 513 static void
 514 set_architecture (char *ignore_args, int from_tty, struct cmd_list_element *c)
 515 {
 516   struct gdbarch_info info;
 517
 518   gdbarch_info_init (&info);
 519
 520   if (strcmp (set_architecture_string, "auto") == 0)
 521     {
 522       target_architecture_user = NULL;
 523       if (!gdbarch_update_p (info))
 524         internal_error (__FILE__, __LINE__,
 525                         _("could not select an architecture automatically"));
 526     }
 527   else
 528     {
 529       info.bfd_arch_info = bfd_scan_arch (set_architecture_string);
 530       if (info.bfd_arch_info == NULL)
 531         internal_error (__FILE__, __LINE__,
 532                         _("set_architecture: bfd_scan_arch failed"));
 533       if (gdbarch_update_p (info))
 534         target_architecture_user = info.bfd_arch_info;
 535       else
 536         printf_unfiltered (_("Architecture `%s' not recognized.\n"),
 537                            set_architecture_string);
 538     }
 539   show_architecture (gdb_stdout, from_tty, NULL, NULL);
 540 }
 541
 542 /* Try to select a global architecture that matches "info".  Return
 543    non-zero if the attempt succeeds.  */
 544 int
 545 gdbarch_update_p (struct gdbarch_info info)
 546 {
 547   struct gdbarch *new_gdbarch;
 548
 549   /* Check for the current file.  */
 550   if (info.abfd == NULL)
 551     info.abfd = exec_bfd;
 552   if (info.abfd == NULL)
 553     info.abfd = core_bfd;
 554
 555   /* Check for the current target description.  */
 556   if (info.target_desc == NULL)
 557     info.target_desc = target_current_description ();
 558
 559   new_gdbarch = gdbarch_find_by_info (info);
 560
 561   /* If there no architecture by that name, reject the request.  */
 562   if (new_gdbarch == NULL)
 563     {
 564       if (gdbarch_debug)
 565         fprintf_unfiltered (gdb_stdlog, "gdbarch_update_p: "
 566                             "Architecture not found\n");
 567       return 0;
 568     }
 569
 570   /* If it is the same old architecture, accept the request (but don't
 571      swap anything).  */
 572   if (new_gdbarch == target_gdbarch ())
 573     {
 574       if (gdbarch_debug)
 575         fprintf_unfiltered (gdb_stdlog, "gdbarch_update_p: "
 576                             "Architecture %s (%s) unchanged\n",
 577                             host_address_to_string (new_gdbarch),
 578                             gdbarch_bfd_arch_info (new_gdbarch)->printable_name);
 579       return 1;
 580     }
 581
 582   /* It's a new architecture, swap it in.  */
 583   if (gdbarch_debug)
 584     fprintf_unfiltered (gdb_stdlog, "gdbarch_update_p: "
 585                         "New architecture %s (%s) selected\n",
 586                         host_address_to_string (new_gdbarch),
 587                         gdbarch_bfd_arch_info (new_gdbarch)->printable_name);
 588   set_target_gdbarch (new_gdbarch);
 589
 590   return 1;
 591 }
 592
 593 /* Return the architecture for ABFD.  If no suitable architecture
 594    could be find, return NULL.  */
 595
 596 struct gdbarch *
 597 gdbarch_from_bfd (bfd *abfd)
 598 {
 599   struct gdbarch_info info;
 600   gdbarch_info_init (&info);
 601
 602   info.abfd = abfd;
 603   return gdbarch_find_by_info (info);
 604 }
 605
 606 /* Set the dynamic target-system-dependent parameters (architecture,
 607    byte-order) using information found in the BFD */
 608
 609 void
 610 set_gdbarch_from_file (bfd *abfd)
 611 {
 612   struct gdbarch_info info;
 613   struct gdbarch *gdbarch;
 614
 615   gdbarch_info_init (&info);
 616   info.abfd = abfd;
 617   info.target_desc = target_current_description ();
 618   gdbarch = gdbarch_find_by_info (info);
 619
 620   if (gdbarch == NULL)
 621     error (_("Architecture of file not recognized."));
 622   set_target_gdbarch (gdbarch);
 623 }
 624
 625 /* Initialize the current architecture.  Update the ``set
 626    architecture'' command so that it specifies a list of valid
 627    architectures.  */
 628
 629 #ifdef DEFAULT_BFD_ARCH
 630 extern const bfd_arch_info_type DEFAULT_BFD_ARCH;
 631 static const bfd_arch_info_type *default_bfd_arch = &DEFAULT_BFD_ARCH;
 632 #else
 633 static const bfd_arch_info_type *default_bfd_arch;
 634 #endif
 635
 636 #ifdef DEFAULT_BFD_VEC
 637 extern const bfd_target DEFAULT_BFD_VEC;
 638 static const bfd_target *default_bfd_vec = &DEFAULT_BFD_VEC;
 639 #else
 640 static const bfd_target *default_bfd_vec;
 641 #endif
 642
 643 static enum bfd_endian default_byte_order = BFD_ENDIAN_UNKNOWN;
 644
 645 void
 646 initialize_current_architecture (void)
 647 {
 648   const char **arches = gdbarch_printable_names ();
 649   struct gdbarch_info info;
 650
 651   /* determine a default architecture and byte order.  */
 652   gdbarch_info_init (&info);
 653
 654   /* Find a default architecture.  */
 655   if (default_bfd_arch == NULL)
 656     {
 657       /* Choose the architecture by taking the first one
 658          alphabetically.  */
 659       const char *chosen = arches[0];
 660       const char **arch;
 661       for (arch = arches; *arch != NULL; arch++)
 662         {
 663           if (strcmp (*arch, chosen) < 0)
 664             chosen = *arch;
 665         }
 666       if (chosen == NULL)
 667         internal_error (__FILE__, __LINE__,
 668                         _("initialize_current_architecture: No arch"));
 669       default_bfd_arch = bfd_scan_arch (chosen);
 670       if (default_bfd_arch == NULL)
 671         internal_error (__FILE__, __LINE__,
 672                         _("initialize_current_architecture: Arch not found"));
 673     }
 674
 675   info.bfd_arch_info = default_bfd_arch;
 676
 677   /* Take several guesses at a byte order.  */
 678   if (default_byte_order == BFD_ENDIAN_UNKNOWN
 679       && default_bfd_vec != NULL)
 680     {
 681       /* Extract BFD's default vector's byte order.  */
 682       switch (default_bfd_vec->byteorder)
 683         {
 684         case BFD_ENDIAN_BIG:
 685           default_byte_order = BFD_ENDIAN_BIG;
 686           break;
 687         case BFD_ENDIAN_LITTLE:
 688           default_byte_order = BFD_ENDIAN_LITTLE;
 689           break;
 690         default:
 691           break;
 692         }
 693     }
 694   if (default_byte_order == BFD_ENDIAN_UNKNOWN)
 695     {
 696       /* look for ``*el-*'' in the target name.  */
 697       const char *chp;
 698       chp = strchr (target_name, '-');
 699       if (chp != NULL
 700           && chp - 2 >= target_name
 701           && startswith (chp - 2, "el"))
 702         default_byte_order = BFD_ENDIAN_LITTLE;
 703     }
 704   if (default_byte_order == BFD_ENDIAN_UNKNOWN)
 705     {
 706       /* Wire it to big-endian!!! */
 707       default_byte_order = BFD_ENDIAN_BIG;
 708     }
 709
 710   info.byte_order = default_byte_order;
 711   info.byte_order_for_code = info.byte_order;
 712
 713   if (! gdbarch_update_p (info))
 714     internal_error (__FILE__, __LINE__,
 715                     _("initialize_current_architecture: Selection of "
 716                       "initial architecture failed"));
 717
 718   /* Create the ``set architecture'' command appending ``auto'' to the
 719      list of architectures.  */
 720   {
 721     /* Append ``auto''.  */
 722     int nr;
 723     for (nr = 0; arches[nr] != NULL; nr++);
 724     arches = XRESIZEVEC (const char *, arches, nr + 2);
 725     arches[nr + 0] = "auto";
 726     arches[nr + 1] = NULL;
 727     add_setshow_enum_cmd ("architecture", class_support,
 728                           arches, &set_architecture_string,
 729                           _("Set architecture of target."),
 730                           _("Show architecture of target."), NULL,
 731                           set_architecture, show_architecture,
 732                           &setlist, &showlist);
 733     add_alias_cmd ("processor", "architecture", class_support, 1, &setlist);
 734   }
 735 }
 736
 737
 738 /* Initialize a gdbarch info to values that will be automatically
 739    overridden.  Note: Originally, this ``struct info'' was initialized
 740    using memset(0).  Unfortunately, that ran into problems, namely
 741    BFD_ENDIAN_BIG is zero.  An explicit initialization function that
 742    can explicitly set each field to a well defined value is used.  */
 743
 744 void
 745 gdbarch_info_init (struct gdbarch_info *info)
 746 {
 747   memset (info, 0, sizeof (struct gdbarch_info));
 748   info->byte_order = BFD_ENDIAN_UNKNOWN;
 749   info->byte_order_for_code = info->byte_order;
 750   info->osabi = GDB_OSABI_UNINITIALIZED;
 751 }
 752
 753 /* Similar to init, but this time fill in the blanks.  Information is
 754    obtained from the global "set ..." options and explicitly
 755    initialized INFO fields.  */
 756
 757 void
 758 gdbarch_info_fill (struct gdbarch_info *info)
 759 {
 760   /* "(gdb) set architecture ...".  */
 761   if (info->bfd_arch_info == NULL
 762       && target_architecture_user)
 763     info->bfd_arch_info = target_architecture_user;
 764   /* From the file.  */
 765   if (info->bfd_arch_info == NULL
 766       && info->abfd != NULL
 767       && bfd_get_arch (info->abfd) != bfd_arch_unknown
 768       && bfd_get_arch (info->abfd) != bfd_arch_obscure)
 769     info->bfd_arch_info = bfd_get_arch_info (info->abfd);
 770   /* From the target.  */
 771   if (info->target_desc != NULL)
 772     info->bfd_arch_info = choose_architecture_for_target
 773                            (info->target_desc, info->bfd_arch_info);
 774   /* From the default.  */
 775   if (info->bfd_arch_info == NULL)
 776     info->bfd_arch_info = default_bfd_arch;
 777
 778   /* "(gdb) set byte-order ...".  */
 779   if (info->byte_order == BFD_ENDIAN_UNKNOWN
 780       && target_byte_order_user != BFD_ENDIAN_UNKNOWN)
 781     info->byte_order = target_byte_order_user;
 782   /* From the INFO struct.  */
 783   if (info->byte_order == BFD_ENDIAN_UNKNOWN
 784       && info->abfd != NULL)
 785     info->byte_order = (bfd_big_endian (info->abfd) ? BFD_ENDIAN_BIG
 786                         : bfd_little_endian (info->abfd) ? BFD_ENDIAN_LITTLE
 787                         : BFD_ENDIAN_UNKNOWN);
 788   /* From the default.  */
 789   if (info->byte_order == BFD_ENDIAN_UNKNOWN)
 790     info->byte_order = default_byte_order;
 791   info->byte_order_for_code = info->byte_order;
 792
 793   /* "(gdb) set osabi ...".  Handled by gdbarch_lookup_osabi.  */
 794   /* From the manual override, or from file.  */
 795   if (info->osabi == GDB_OSABI_UNINITIALIZED)
 796     info->osabi = gdbarch_lookup_osabi (info->abfd);
 797   /* From the target.  */
 798   if (info->osabi == GDB_OSABI_UNKNOWN && info->target_desc != NULL)
 799     info->osabi = tdesc_osabi (info->target_desc);
 800   /* From the configured default.  */
 801 #ifdef GDB_OSABI_DEFAULT
 802   if (info->osabi == GDB_OSABI_UNKNOWN)
 803     info->osabi = GDB_OSABI_DEFAULT;
 804 #endif
 805
 806   /* Must have at least filled in the architecture.  */
 807   gdb_assert (info->bfd_arch_info != NULL);
 808 }
 809
 810 /* Return "current" architecture.  If the target is running, this is
 811    the architecture of the selected frame.  Otherwise, the "current"
 812    architecture defaults to the target architecture.
 813
 814    This function should normally be called solely by the command
 815    interpreter routines to determine the architecture to execute a
 816    command in.  */
 817 struct gdbarch *
 818 get_current_arch (void)
 819 {
 820   if (has_stack_frames ())
 821     return get_frame_arch (get_selected_frame (NULL));
 822   else
 823     return target_gdbarch ();
 824 }
 825
 826 int
 827 default_has_shared_address_space (struct gdbarch *gdbarch)
 828 {
 829   /* Simply say no.  In most unix-like targets each inferior/process
 830      has its own address space.  */
 831   return 0;
 832 }
 833
 834 int
 835 default_fast_tracepoint_valid_at (struct gdbarch *gdbarch, CORE_ADDR addr,
 836                                   char **msg)
 837 {
 838   /* We don't know if maybe the target has some way to do fast
 839      tracepoints that doesn't need gdbarch, so always say yes.  */
 840   if (msg)
 841     *msg = NULL;
 842   return 1;
 843 }
 844
 845 const gdb_byte *
 846 default_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr,
 847                             int *lenptr)
 848 {
 849   int kind = gdbarch_breakpoint_kind_from_pc (gdbarch, pcptr);
 850
 851   return gdbarch_sw_breakpoint_from_kind (gdbarch, kind, lenptr);
 852 }
 853 int
 854 default_breakpoint_kind_from_current_state (struct gdbarch *gdbarch,
 855                                             struct regcache *regcache,
 856                                             CORE_ADDR *pcptr)
 857 {
 858   return gdbarch_breakpoint_kind_from_pc (gdbarch, pcptr);
 859 }
 860
 861
 862 void
 863 default_gen_return_address (struct gdbarch *gdbarch,
 864                             struct agent_expr *ax, struct axs_value *value,
 865                             CORE_ADDR scope)
 866 {
 867   error (_("This architecture has no method to collect a return address."));
 868 }
 869
 870 int
 871 default_return_in_first_hidden_param_p (struct gdbarch *gdbarch,
 872                                         struct type *type)
 873 {
 874   /* Usually, the return value's address is stored the in the "first hidden"
 875      parameter if the return value should be passed by reference, as
 876      specified in ABI.  */
 877   return language_pass_by_reference (type);
 878 }
 879
 880 int default_insn_is_call (struct gdbarch *gdbarch, CORE_ADDR addr)
 881 {
 882   return 0;
 883 }
 884
 885 int default_insn_is_ret (struct gdbarch *gdbarch, CORE_ADDR addr)
 886 {
 887   return 0;
 888 }
 889
 890 int default_insn_is_jump (struct gdbarch *gdbarch, CORE_ADDR addr)
 891 {
 892   return 0;
 893 }
 894
 895 void
 896 default_skip_permanent_breakpoint (struct regcache *regcache)
 897 {
 898   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 899   CORE_ADDR current_pc = regcache_read_pc (regcache);
 900   int bp_len;
 901
 902   gdbarch_breakpoint_from_pc (gdbarch, &current_pc, &bp_len);
 903   current_pc += bp_len;
 904   regcache_write_pc (regcache, current_pc);
 905 }
 906
 907 CORE_ADDR
 908 default_infcall_mmap (CORE_ADDR size, unsigned prot)
 909 {
 910   error (_("This target does not support inferior memory allocation by mmap."));
 911 }
 912
 913 void
 914 default_infcall_munmap (CORE_ADDR addr, CORE_ADDR size)
 915 {
 916   /* Memory reserved by inferior mmap is kept leaked.  */
 917 }
 918
 919 /* -mcmodel=large is used so that no GOT (Global Offset Table) is needed to be
 920    created in inferior memory by GDB (normally it is set by ld.so).  */
 921
 922 char *
 923 default_gcc_target_options (struct gdbarch *gdbarch)
 924 {
 925   return xstrprintf ("-m%d%s", gdbarch_ptr_bit (gdbarch),
 926                      gdbarch_ptr_bit (gdbarch) == 64 ? " -mcmodel=large" : "");
 927 }
 928
 929 /* gdbarch gnu_triplet_regexp method.  */
 930
 931 const char *
 932 default_gnu_triplet_regexp (struct gdbarch *gdbarch)
 933 {
 934   return gdbarch_bfd_arch_info (gdbarch)->arch_name;
 935 }
 936
 937 /* Default method for gdbarch_addressable_memory_unit_size.  By default, a memory byte has
 938    a size of 1 octet.  */
 939
 940 int
 941 default_addressable_memory_unit_size (struct gdbarch *gdbarch)
 942 {
 943   return 1;
 944 }
 945
 946 void
 947 default_guess_tracepoint_registers (struct gdbarch *gdbarch,
 948                                     struct regcache *regcache,
 949                                     CORE_ADDR addr)
 950 {
 951   int pc_regno = gdbarch_pc_regnum (gdbarch);
 952   gdb_byte *regs;
 953
 954   /* This guessing code below only works if the PC register isn't
 955      a pseudo-register.  The value of a pseudo-register isn't stored
 956      in the (non-readonly) regcache -- instead it's recomputed
 957      (probably from some other cached raw register) whenever the
 958      register is read.  In this case, a custom method implementation
 959      should be used by the architecture.  */
 960   if (pc_regno < 0 || pc_regno >= gdbarch_num_regs (gdbarch))
 961     return;
 962
 963   regs = (gdb_byte *) alloca (register_size (gdbarch, pc_regno));
 964   store_unsigned_integer (regs, register_size (gdbarch, pc_regno),
 965                           gdbarch_byte_order (gdbarch), addr);
 966   regcache_raw_supply (regcache, pc_regno, regs);
 967 }
 968
 969 int
 970 default_print_insn (bfd_vma memaddr, disassemble_info *info)
 971 {
 972   disassembler_ftype disassemble_fn;
 973
 974   disassemble_fn = disassembler (info->arch, info->endian == BFD_ENDIAN_BIG,
 975                                  info->mach, exec_bfd);
 976
 977   gdb_assert (disassemble_fn != NULL);
 978   return (*disassemble_fn) (memaddr, info);
 979 }
 980
 981 /* See arch-utils.h.  */
 982
 983 CORE_ADDR
 984 gdbarch_skip_prologue_noexcept (gdbarch *gdbarch, CORE_ADDR pc) noexcept
 985 {
 986   CORE_ADDR new_pc = pc;
 987
 988   TRY
 989     {
 990       new_pc = gdbarch_skip_prologue (gdbarch, pc);
 991     }
 992   CATCH (ex, RETURN_MASK_ALL)
 993     {}
 994   END_CATCH
 995
 996   return new_pc;
 997 }
 998
 999 /* -Wmissing-prototypes */
1000 extern initialize_file_ftype _initialize_gdbarch_utils;
1001
1002 void
1003 _initialize_gdbarch_utils (void)
1004 {
1005   add_setshow_enum_cmd ("endian", class_support,
1006                         endian_enum, &set_endian_string,
1007                         _("Set endianness of target."),
1008                         _("Show endianness of target."),
1009                         NULL, set_endian, show_endian,
1010                         &setlist, &showlist);
1011 }