gdb/vax-tdep.c

   1 /* Print VAX instructions for GDB, the GNU debugger.
   2    Copyright 1986, 1989, 1991, 1992, 1995, 1996, 1998, 1999, 2000, 2002, 2003
   3    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 2 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, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "defs.h"
  23 #include "symtab.h"
  24 #include "opcode/vax.h"
  25 #include "gdbcore.h"
  26 #include "inferior.h"
  27 #include "regcache.h"
  28 #include "frame.h"
  29 #include "value.h"
  30 #include "arch-utils.h"
  31 #include "gdb_string.h"
  32 #include "osabi.h"
  33
  34 #include "vax-tdep.h"
  35
  36 static gdbarch_register_name_ftype vax_register_name;
  37 static gdbarch_register_byte_ftype vax_register_byte;
  38 static gdbarch_register_raw_size_ftype vax_register_raw_size;
  39 static gdbarch_register_virtual_size_ftype vax_register_virtual_size;
  40 static gdbarch_register_virtual_type_ftype vax_register_virtual_type;
  41
  42 static gdbarch_skip_prologue_ftype vax_skip_prologue;
  43 static gdbarch_frame_num_args_ftype vax_frame_num_args;
  44 static gdbarch_deprecated_frame_chain_ftype vax_frame_chain;
  45 static gdbarch_frame_args_address_ftype vax_frame_args_address;
  46 static gdbarch_frame_locals_address_ftype vax_frame_locals_address;
  47
  48 static gdbarch_deprecated_extract_return_value_ftype vax_extract_return_value;
  49 static gdbarch_deprecated_extract_struct_value_address_ftype
  50     vax_extract_struct_value_address;
  51
  52 static gdbarch_deprecated_push_dummy_frame_ftype vax_push_dummy_frame;
  53 \f
  54 static const char *
  55 vax_register_name (int regno)
  56 {
  57   static char *register_names[] =
  58   {
  59     "r0",  "r1",  "r2",  "r3", "r4", "r5", "r6", "r7",
  60     "r8",  "r9", "r10", "r11", "ap", "fp", "sp", "pc",
  61     "ps",
  62   };
  63
  64   if (regno < 0)
  65     return (NULL);
  66   if (regno >= (sizeof(register_names) / sizeof(*register_names)))
  67     return (NULL);
  68   return (register_names[regno]);
  69 }
  70
  71 static int
  72 vax_register_byte (int regno)
  73 {
  74   return (regno * 4);
  75 }
  76
  77 static int
  78 vax_register_raw_size (int regno)
  79 {
  80   return (4);
  81 }
  82
  83 static int
  84 vax_register_virtual_size (int regno)
  85 {
  86   return (4);
  87 }
  88
  89 static struct type *
  90 vax_register_virtual_type (int regno)
  91 {
  92   return (builtin_type_int);
  93 }
  94 \f
  95 static void
  96 vax_frame_init_saved_regs (struct frame_info *frame)
  97 {
  98   int regnum, regmask;
  99   CORE_ADDR next_addr;
 100
 101   if (get_frame_saved_regs (frame))
 102     return;
 103
 104   frame_saved_regs_zalloc (frame);
 105
 106   regmask = read_memory_integer (get_frame_base (frame) + 4, 4) >> 16;
 107
 108   next_addr = get_frame_base (frame) + 16;
 109
 110   /* regmask's low bit is for register 0, which is the first one
 111      what would be pushed.  */
 112   for (regnum = 0; regnum < VAX_AP_REGNUM; regnum++)
 113     {
 114       if (regmask & (1 << regnum))
 115         get_frame_saved_regs (frame)[regnum] = next_addr += 4;
 116     }
 117
 118   get_frame_saved_regs (frame)[SP_REGNUM] = next_addr + 4;
 119   if (regmask & (1 << DEPRECATED_FP_REGNUM))
 120     get_frame_saved_regs (frame)[SP_REGNUM] +=
 121       4 + (4 * read_memory_integer (next_addr + 4, 4));
 122
 123   get_frame_saved_regs (frame)[PC_REGNUM] = get_frame_base (frame) + 16;
 124   get_frame_saved_regs (frame)[DEPRECATED_FP_REGNUM] = get_frame_base (frame) + 12;
 125   get_frame_saved_regs (frame)[VAX_AP_REGNUM] = get_frame_base (frame) + 8;
 126   get_frame_saved_regs (frame)[PS_REGNUM] = get_frame_base (frame) + 4;
 127 }
 128
 129 /* Get saved user PC for sigtramp from sigcontext for BSD style sigtramp.  */
 130
 131 static CORE_ADDR
 132 vax_sigtramp_saved_pc (struct frame_info *frame)
 133 {
 134   CORE_ADDR sigcontext_addr;
 135   char *buf;
 136   int ptrbytes = TYPE_LENGTH (builtin_type_void_func_ptr);
 137   int sigcontext_offs = (2 * TARGET_INT_BIT) / TARGET_CHAR_BIT;
 138
 139   buf = alloca (ptrbytes);
 140   /* Get sigcontext address, it is the third parameter on the stack.  */
 141   if (get_next_frame (frame))
 142     sigcontext_addr = read_memory_typed_address
 143       (FRAME_ARGS_ADDRESS (get_next_frame (frame))
 144        + FRAME_ARGS_SKIP + sigcontext_offs,
 145        builtin_type_void_data_ptr);
 146   else
 147     sigcontext_addr = read_memory_typed_address
 148       (read_register (SP_REGNUM) + sigcontext_offs, builtin_type_void_data_ptr);
 149
 150   /* Don't cause a memory_error when accessing sigcontext in case the stack
 151      layout has changed or the stack is corrupt.  */
 152   target_read_memory (sigcontext_addr + SIGCONTEXT_PC_OFFSET, buf, ptrbytes);
 153   return extract_typed_address (buf, builtin_type_void_func_ptr);
 154 }
 155
 156 static CORE_ADDR
 157 vax_frame_saved_pc (struct frame_info *frame)
 158 {
 159   if ((get_frame_type (frame) == SIGTRAMP_FRAME))
 160     return (vax_sigtramp_saved_pc (frame)); /* XXXJRT */
 161
 162   return (read_memory_integer (get_frame_base (frame) + 16, 4));
 163 }
 164
 165 static CORE_ADDR
 166 vax_frame_args_address (struct frame_info *frame)
 167 {
 168   /* In most of GDB, getting the args address is too important to just
 169      say "I don't know".  This is sometimes wrong for functions that
 170      aren't on top of the stack, but c'est la vie.  */
 171   if (get_next_frame (frame))
 172     return (read_memory_integer (get_frame_base (get_next_frame (frame)) + 8, 4));
 173   /* Cannot find the AP register value directly from the FP value.
 174      Must find it saved in the frame called by this one, or in the AP
 175      register for the innermost frame.  However, there is no way to
 176      tell the difference between the innermost frame and a frame for
 177      which we just don't know the frame that it called (e.g. "info
 178      frame 0x7ffec789").  For the sake of argument, suppose that the
 179      stack is somewhat trashed (which is one reason that "info frame"
 180      exists).  So, return 0 (indicating we don't know the address of
 181      the arglist) if we don't know what frame this frame calls.  */
 182   return 0;
 183 }
 184
 185 static CORE_ADDR
 186 vax_frame_locals_address (struct frame_info *frame)
 187 {
 188   return (get_frame_base (frame));
 189 }
 190
 191 static int
 192 vax_frame_num_args (struct frame_info *fi)
 193 {
 194   return (0xff & read_memory_integer (FRAME_ARGS_ADDRESS (fi), 1));
 195 }
 196
 197 static CORE_ADDR
 198 vax_frame_chain (struct frame_info *frame)
 199 {
 200   /* In the case of the VAX, the frame's nominal address is the FP value,
 201      and 12 bytes later comes the saved previous FP value as a 4-byte word.  */
 202   if (inside_entry_file (get_frame_pc (frame)))
 203     return (0);
 204
 205   return (read_memory_integer (get_frame_base (frame) + 12, 4));
 206 }
 207 \f
 208 static void
 209 vax_push_dummy_frame (void)
 210 {
 211   CORE_ADDR sp = read_register (SP_REGNUM);
 212   int regnum;
 213
 214   sp = push_word (sp, 0);       /* arglist */
 215   for (regnum = 11; regnum >= 0; regnum--)
 216     sp = push_word (sp, read_register (regnum));
 217   sp = push_word (sp, read_register (PC_REGNUM));
 218   sp = push_word (sp, read_register (DEPRECATED_FP_REGNUM));
 219   sp = push_word (sp, read_register (VAX_AP_REGNUM));
 220   sp = push_word (sp, (read_register (PS_REGNUM) & 0xffef) + 0x2fff0000);
 221   sp = push_word (sp, 0);
 222   write_register (SP_REGNUM, sp);
 223   write_register (DEPRECATED_FP_REGNUM, sp);
 224   write_register (VAX_AP_REGNUM, sp + (17 * 4));
 225 }
 226
 227 static void
 228 vax_pop_frame (void)
 229 {
 230   CORE_ADDR fp = read_register (DEPRECATED_FP_REGNUM);
 231   int regnum;
 232   int regmask = read_memory_integer (fp + 4, 4);
 233
 234   write_register (PS_REGNUM,
 235                   (regmask & 0xffff)
 236                   | (read_register (PS_REGNUM) & 0xffff0000));
 237   write_register (PC_REGNUM, read_memory_integer (fp + 16, 4));
 238   write_register (DEPRECATED_FP_REGNUM, read_memory_integer (fp + 12, 4));
 239   write_register (VAX_AP_REGNUM, read_memory_integer (fp + 8, 4));
 240   fp += 16;
 241   for (regnum = 0; regnum < 12; regnum++)
 242     if (regmask & (0x10000 << regnum))
 243       write_register (regnum, read_memory_integer (fp += 4, 4));
 244   fp = fp + 4 + ((regmask >> 30) & 3);
 245   if (regmask & 0x20000000)
 246     {
 247       regnum = read_memory_integer (fp, 4);
 248       fp += (regnum + 1) * 4;
 249     }
 250   write_register (SP_REGNUM, fp);
 251   flush_cached_frames ();
 252 }
 253
 254 /* The VAX call dummy sequence:
 255
 256         calls #69, @#32323232
 257         bpt
 258
 259    It is 8 bytes long.  The address and argc are patched by
 260    vax_fix_call_dummy().  */
 261 static LONGEST vax_call_dummy_words[] = { 0x329f69fb, 0x03323232 };
 262 static int sizeof_vax_call_dummy_words = sizeof(vax_call_dummy_words);
 263
 264 static void
 265 vax_fix_call_dummy (char *dummy, CORE_ADDR pc, CORE_ADDR fun, int nargs,
 266                     struct value **args, struct type *type, int gcc_p)
 267 {
 268   dummy[1] = nargs;
 269   store_unsigned_integer (dummy + 3, 4, fun);
 270 }
 271 \f
 272 static void
 273 vax_store_struct_return (CORE_ADDR addr, CORE_ADDR sp)
 274 {
 275   write_register (1, addr);
 276 }
 277
 278 static void
 279 vax_extract_return_value (struct type *valtype, char *regbuf, char *valbuf)
 280 {
 281   memcpy (valbuf, regbuf + REGISTER_BYTE (0), TYPE_LENGTH (valtype));
 282 }
 283
 284 static void
 285 vax_store_return_value (struct type *valtype, char *valbuf)
 286 {
 287   deprecated_write_register_bytes (0, valbuf, TYPE_LENGTH (valtype));
 288 }
 289
 290 static CORE_ADDR
 291 vax_extract_struct_value_address (char *regbuf)
 292 {
 293   return (extract_unsigned_integer (regbuf + REGISTER_BYTE (0),
 294                                     REGISTER_RAW_SIZE (0)));
 295 }
 296 \f
 297 static const unsigned char *
 298 vax_breakpoint_from_pc (CORE_ADDR *pcptr, int *lenptr)
 299 {
 300   static const unsigned char vax_breakpoint[] = { 3 };
 301
 302   *lenptr = sizeof(vax_breakpoint);
 303   return (vax_breakpoint);
 304 }
 305 \f
 306 /* Advance PC across any function entry prologue instructions
 307    to reach some "real" code.  */
 308
 309 static CORE_ADDR
 310 vax_skip_prologue (CORE_ADDR pc)
 311 {
 312   register int op = (unsigned char) read_memory_integer (pc, 1);
 313   if (op == 0x11)
 314     pc += 2;                    /* skip brb */
 315   if (op == 0x31)
 316     pc += 3;                    /* skip brw */
 317   if (op == 0xC2
 318       && ((unsigned char) read_memory_integer (pc + 2, 1)) == 0x5E)
 319     pc += 3;                    /* skip subl2 */
 320   if (op == 0x9E
 321       && ((unsigned char) read_memory_integer (pc + 1, 1)) == 0xAE
 322       && ((unsigned char) read_memory_integer (pc + 3, 1)) == 0x5E)
 323     pc += 4;                    /* skip movab */
 324   if (op == 0x9E
 325       && ((unsigned char) read_memory_integer (pc + 1, 1)) == 0xCE
 326       && ((unsigned char) read_memory_integer (pc + 4, 1)) == 0x5E)
 327     pc += 5;                    /* skip movab */
 328   if (op == 0x9E
 329       && ((unsigned char) read_memory_integer (pc + 1, 1)) == 0xEE
 330       && ((unsigned char) read_memory_integer (pc + 6, 1)) == 0x5E)
 331     pc += 7;                    /* skip movab */
 332   return pc;
 333 }
 334
 335 static CORE_ADDR
 336 vax_saved_pc_after_call (struct frame_info *frame)
 337 {
 338   return (DEPRECATED_FRAME_SAVED_PC(frame));
 339 }
 340 \f
 341 /* Initialize the current architecture based on INFO.  If possible, re-use an
 342    architecture from ARCHES, which is a list of architectures already created
 343    during this debugging session.
 344
 345    Called e.g. at program startup, when reading a core file, and when reading
 346    a binary file.  */
 347
 348 static struct gdbarch *
 349 vax_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 350 {
 351   struct gdbarch *gdbarch;
 352
 353   /* If there is already a candidate, use it.  */
 354   arches = gdbarch_list_lookup_by_info (arches, &info);
 355   if (arches != NULL)
 356     return arches->gdbarch;
 357
 358   gdbarch = gdbarch_alloc (&info, NULL);
 359
 360   /* NOTE: cagney/2002-12-06: This can be deleted when this arch is
 361      ready to unwind the PC first (see frame.c:get_prev_frame()).  */
 362   set_gdbarch_deprecated_init_frame_pc (gdbarch, init_frame_pc_default);
 363
 364   /* Register info */
 365   set_gdbarch_num_regs (gdbarch, VAX_NUM_REGS);
 366   set_gdbarch_sp_regnum (gdbarch, VAX_SP_REGNUM);
 367   set_gdbarch_deprecated_fp_regnum (gdbarch, VAX_FP_REGNUM);
 368   set_gdbarch_pc_regnum (gdbarch, VAX_PC_REGNUM);
 369   set_gdbarch_ps_regnum (gdbarch, VAX_PS_REGNUM);
 370
 371   set_gdbarch_register_name (gdbarch, vax_register_name);
 372   set_gdbarch_deprecated_register_size (gdbarch, VAX_REGISTER_SIZE);
 373   set_gdbarch_deprecated_register_bytes (gdbarch, VAX_REGISTER_BYTES);
 374   set_gdbarch_register_byte (gdbarch, vax_register_byte);
 375   set_gdbarch_register_raw_size (gdbarch, vax_register_raw_size);
 376   set_gdbarch_deprecated_max_register_raw_size (gdbarch, VAX_MAX_REGISTER_RAW_SIZE);
 377   set_gdbarch_register_virtual_size (gdbarch, vax_register_virtual_size);
 378   set_gdbarch_deprecated_max_register_virtual_size (gdbarch,
 379                                          VAX_MAX_REGISTER_VIRTUAL_SIZE);
 380   set_gdbarch_register_virtual_type (gdbarch, vax_register_virtual_type);
 381
 382   /* Frame and stack info */
 383   set_gdbarch_skip_prologue (gdbarch, vax_skip_prologue);
 384   set_gdbarch_deprecated_saved_pc_after_call (gdbarch, vax_saved_pc_after_call);
 385
 386   set_gdbarch_frame_num_args (gdbarch, vax_frame_num_args);
 387   set_gdbarch_frameless_function_invocation (gdbarch,
 388                                    generic_frameless_function_invocation_not);
 389
 390   set_gdbarch_deprecated_frame_chain (gdbarch, vax_frame_chain);
 391   set_gdbarch_deprecated_frame_saved_pc (gdbarch, vax_frame_saved_pc);
 392
 393   set_gdbarch_frame_args_address (gdbarch, vax_frame_args_address);
 394   set_gdbarch_frame_locals_address (gdbarch, vax_frame_locals_address);
 395
 396   set_gdbarch_deprecated_frame_init_saved_regs (gdbarch, vax_frame_init_saved_regs);
 397
 398   set_gdbarch_frame_args_skip (gdbarch, 4);
 399
 400   set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
 401
 402   /* Return value info */
 403   set_gdbarch_deprecated_store_struct_return (gdbarch, vax_store_struct_return);
 404   set_gdbarch_deprecated_extract_return_value (gdbarch, vax_extract_return_value);
 405   set_gdbarch_deprecated_store_return_value (gdbarch, vax_store_return_value);
 406   set_gdbarch_deprecated_extract_struct_value_address (gdbarch, vax_extract_struct_value_address);
 407
 408   /* Call dummy info */
 409   set_gdbarch_deprecated_push_dummy_frame (gdbarch, vax_push_dummy_frame);
 410   set_gdbarch_deprecated_pop_frame (gdbarch, vax_pop_frame);
 411   set_gdbarch_call_dummy_location (gdbarch, ON_STACK);
 412   set_gdbarch_deprecated_call_dummy_words (gdbarch, vax_call_dummy_words);
 413   set_gdbarch_deprecated_sizeof_call_dummy_words (gdbarch, sizeof_vax_call_dummy_words);
 414   set_gdbarch_deprecated_fix_call_dummy (gdbarch, vax_fix_call_dummy);
 415   set_gdbarch_deprecated_call_dummy_breakpoint_offset (gdbarch, 7);
 416   set_gdbarch_deprecated_use_generic_dummy_frames (gdbarch, 0);
 417   set_gdbarch_deprecated_pc_in_call_dummy (gdbarch, deprecated_pc_in_call_dummy_on_stack);
 418
 419   /* Breakpoint info */
 420   set_gdbarch_breakpoint_from_pc (gdbarch, vax_breakpoint_from_pc);
 421   set_gdbarch_decr_pc_after_break (gdbarch, 0);
 422
 423   /* Misc info */
 424   set_gdbarch_function_start_offset (gdbarch, 2);
 425   set_gdbarch_believe_pcc_promotion (gdbarch, 1);
 426
 427   /* Should be using push_dummy_call.  */
 428   set_gdbarch_deprecated_dummy_write_sp (gdbarch, deprecated_write_sp);
 429
 430   /* Hook in ABI-specific overrides, if they have been registered.  */
 431   gdbarch_init_osabi (info, gdbarch);
 432
 433   set_gdbarch_print_insn (gdbarch, print_insn_vax);
 434
 435   return (gdbarch);
 436 }
 437
 438 void
 439 _initialize_vax_tdep (void)
 440 {
 441   gdbarch_register (bfd_arch_vax, vax_gdbarch_init, NULL);
 442 }