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 CORE_ADDR
 166 vax_frame_args_address_correct (struct frame_info *frame)
 167 {
 168   /* Cannot find the AP register value directly from the FP value.  Must
 169      find it saved in the frame called by this one, or in the AP register
 170      for the innermost frame.  However, there is no way to tell the
 171      difference between the innermost frame and a frame for which we
 172      just don't know the frame that it called (e.g. "info frame 0x7ffec789").
 173      For the sake of argument, suppose that the stack is somewhat trashed
 174      (which is one reason that "info frame" exists).  So, return 0 (indicating
 175      we don't know the address of the arglist) if we don't know what frame
 176      this frame calls.  */
 177   if (get_next_frame (frame))
 178     return (read_memory_integer (get_frame_base (get_next_frame (frame)) + 8, 4));
 179
 180   return (0);
 181 }
 182
 183 static CORE_ADDR
 184 vax_frame_args_address (struct frame_info *frame)
 185 {
 186   /* In most of GDB, getting the args address is too important to
 187      just say "I don't know".  This is sometimes wrong for functions
 188      that aren't on top of the stack, but c'est la vie.  */
 189   if (get_next_frame (frame))
 190     return (read_memory_integer (get_frame_base (get_next_frame (frame)) + 8, 4));
 191
 192   return (read_register (VAX_AP_REGNUM));
 193 }
 194
 195 static CORE_ADDR
 196 vax_frame_locals_address (struct frame_info *frame)
 197 {
 198   return (get_frame_base (frame));
 199 }
 200
 201 static int
 202 vax_frame_num_args (struct frame_info *fi)
 203 {
 204   return (0xff & read_memory_integer (FRAME_ARGS_ADDRESS (fi), 1));
 205 }
 206
 207 static CORE_ADDR
 208 vax_frame_chain (struct frame_info *frame)
 209 {
 210   /* In the case of the VAX, the frame's nominal address is the FP value,
 211      and 12 bytes later comes the saved previous FP value as a 4-byte word.  */
 212   if (inside_entry_file (get_frame_pc (frame)))
 213     return (0);
 214
 215   return (read_memory_integer (get_frame_base (frame) + 12, 4));
 216 }
 217 \f
 218 static void
 219 vax_push_dummy_frame (void)
 220 {
 221   CORE_ADDR sp = read_register (SP_REGNUM);
 222   int regnum;
 223
 224   sp = push_word (sp, 0);       /* arglist */
 225   for (regnum = 11; regnum >= 0; regnum--)
 226     sp = push_word (sp, read_register (regnum));
 227   sp = push_word (sp, read_register (PC_REGNUM));
 228   sp = push_word (sp, read_register (DEPRECATED_FP_REGNUM));
 229   sp = push_word (sp, read_register (VAX_AP_REGNUM));
 230   sp = push_word (sp, (read_register (PS_REGNUM) & 0xffef) + 0x2fff0000);
 231   sp = push_word (sp, 0);
 232   write_register (SP_REGNUM, sp);
 233   write_register (DEPRECATED_FP_REGNUM, sp);
 234   write_register (VAX_AP_REGNUM, sp + (17 * 4));
 235 }
 236
 237 static void
 238 vax_pop_frame (void)
 239 {
 240   CORE_ADDR fp = read_register (DEPRECATED_FP_REGNUM);
 241   int regnum;
 242   int regmask = read_memory_integer (fp + 4, 4);
 243
 244   write_register (PS_REGNUM,
 245                   (regmask & 0xffff)
 246                   | (read_register (PS_REGNUM) & 0xffff0000));
 247   write_register (PC_REGNUM, read_memory_integer (fp + 16, 4));
 248   write_register (DEPRECATED_FP_REGNUM, read_memory_integer (fp + 12, 4));
 249   write_register (VAX_AP_REGNUM, read_memory_integer (fp + 8, 4));
 250   fp += 16;
 251   for (regnum = 0; regnum < 12; regnum++)
 252     if (regmask & (0x10000 << regnum))
 253       write_register (regnum, read_memory_integer (fp += 4, 4));
 254   fp = fp + 4 + ((regmask >> 30) & 3);
 255   if (regmask & 0x20000000)
 256     {
 257       regnum = read_memory_integer (fp, 4);
 258       fp += (regnum + 1) * 4;
 259     }
 260   write_register (SP_REGNUM, fp);
 261   flush_cached_frames ();
 262 }
 263
 264 /* The VAX call dummy sequence:
 265
 266         calls #69, @#32323232
 267         bpt
 268
 269    It is 8 bytes long.  The address and argc are patched by
 270    vax_fix_call_dummy().  */
 271 static LONGEST vax_call_dummy_words[] = { 0x329f69fb, 0x03323232 };
 272 static int sizeof_vax_call_dummy_words = sizeof(vax_call_dummy_words);
 273
 274 static void
 275 vax_fix_call_dummy (char *dummy, CORE_ADDR pc, CORE_ADDR fun, int nargs,
 276                     struct value **args, struct type *type, int gcc_p)
 277 {
 278   dummy[1] = nargs;
 279   store_unsigned_integer (dummy + 3, 4, fun);
 280 }
 281 \f
 282 static void
 283 vax_store_struct_return (CORE_ADDR addr, CORE_ADDR sp)
 284 {
 285   write_register (1, addr);
 286 }
 287
 288 static void
 289 vax_extract_return_value (struct type *valtype, char *regbuf, char *valbuf)
 290 {
 291   memcpy (valbuf, regbuf + REGISTER_BYTE (0), TYPE_LENGTH (valtype));
 292 }
 293
 294 static void
 295 vax_store_return_value (struct type *valtype, char *valbuf)
 296 {
 297   deprecated_write_register_bytes (0, valbuf, TYPE_LENGTH (valtype));
 298 }
 299
 300 static CORE_ADDR
 301 vax_extract_struct_value_address (char *regbuf)
 302 {
 303   return (extract_address (regbuf + REGISTER_BYTE (0), REGISTER_RAW_SIZE (0)));
 304 }
 305 \f
 306 static const unsigned char *
 307 vax_breakpoint_from_pc (CORE_ADDR *pcptr, int *lenptr)
 308 {
 309   static const unsigned char vax_breakpoint[] = { 3 };
 310
 311   *lenptr = sizeof(vax_breakpoint);
 312   return (vax_breakpoint);
 313 }
 314 \f
 315 /* Advance PC across any function entry prologue instructions
 316    to reach some "real" code.  */
 317
 318 static CORE_ADDR
 319 vax_skip_prologue (CORE_ADDR pc)
 320 {
 321   register int op = (unsigned char) read_memory_integer (pc, 1);
 322   if (op == 0x11)
 323     pc += 2;                    /* skip brb */
 324   if (op == 0x31)
 325     pc += 3;                    /* skip brw */
 326   if (op == 0xC2
 327       && ((unsigned char) read_memory_integer (pc + 2, 1)) == 0x5E)
 328     pc += 3;                    /* skip subl2 */
 329   if (op == 0x9E
 330       && ((unsigned char) read_memory_integer (pc + 1, 1)) == 0xAE
 331       && ((unsigned char) read_memory_integer (pc + 3, 1)) == 0x5E)
 332     pc += 4;                    /* skip movab */
 333   if (op == 0x9E
 334       && ((unsigned char) read_memory_integer (pc + 1, 1)) == 0xCE
 335       && ((unsigned char) read_memory_integer (pc + 4, 1)) == 0x5E)
 336     pc += 5;                    /* skip movab */
 337   if (op == 0x9E
 338       && ((unsigned char) read_memory_integer (pc + 1, 1)) == 0xEE
 339       && ((unsigned char) read_memory_integer (pc + 6, 1)) == 0x5E)
 340     pc += 7;                    /* skip movab */
 341   return pc;
 342 }
 343
 344 static CORE_ADDR
 345 vax_saved_pc_after_call (struct frame_info *frame)
 346 {
 347   return (DEPRECATED_FRAME_SAVED_PC(frame));
 348 }
 349 \f
 350 /* Initialize the current architecture based on INFO.  If possible, re-use an
 351    architecture from ARCHES, which is a list of architectures already created
 352    during this debugging session.
 353
 354    Called e.g. at program startup, when reading a core file, and when reading
 355    a binary file.  */
 356
 357 static struct gdbarch *
 358 vax_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 359 {
 360   struct gdbarch *gdbarch;
 361
 362   /* If there is already a candidate, use it.  */
 363   arches = gdbarch_list_lookup_by_info (arches, &info);
 364   if (arches != NULL)
 365     return arches->gdbarch;
 366
 367   gdbarch = gdbarch_alloc (&info, NULL);
 368
 369   /* NOTE: cagney/2002-12-06: This can be deleted when this arch is
 370      ready to unwind the PC first (see frame.c:get_prev_frame()).  */
 371   set_gdbarch_deprecated_init_frame_pc (gdbarch, init_frame_pc_default);
 372
 373   /* Register info */
 374   set_gdbarch_num_regs (gdbarch, VAX_NUM_REGS);
 375   set_gdbarch_sp_regnum (gdbarch, VAX_SP_REGNUM);
 376   set_gdbarch_deprecated_fp_regnum (gdbarch, VAX_FP_REGNUM);
 377   set_gdbarch_pc_regnum (gdbarch, VAX_PC_REGNUM);
 378   set_gdbarch_ps_regnum (gdbarch, VAX_PS_REGNUM);
 379
 380   set_gdbarch_register_name (gdbarch, vax_register_name);
 381   set_gdbarch_deprecated_register_size (gdbarch, VAX_REGISTER_SIZE);
 382   set_gdbarch_register_bytes (gdbarch, VAX_REGISTER_BYTES);
 383   set_gdbarch_register_byte (gdbarch, vax_register_byte);
 384   set_gdbarch_register_raw_size (gdbarch, vax_register_raw_size);
 385   set_gdbarch_deprecated_max_register_raw_size (gdbarch, VAX_MAX_REGISTER_RAW_SIZE);
 386   set_gdbarch_register_virtual_size (gdbarch, vax_register_virtual_size);
 387   set_gdbarch_deprecated_max_register_virtual_size (gdbarch,
 388                                          VAX_MAX_REGISTER_VIRTUAL_SIZE);
 389   set_gdbarch_register_virtual_type (gdbarch, vax_register_virtual_type);
 390
 391   /* Frame and stack info */
 392   set_gdbarch_skip_prologue (gdbarch, vax_skip_prologue);
 393   set_gdbarch_deprecated_saved_pc_after_call (gdbarch, vax_saved_pc_after_call);
 394
 395   set_gdbarch_frame_num_args (gdbarch, vax_frame_num_args);
 396   set_gdbarch_frameless_function_invocation (gdbarch,
 397                                    generic_frameless_function_invocation_not);
 398
 399   set_gdbarch_deprecated_frame_chain (gdbarch, vax_frame_chain);
 400   set_gdbarch_deprecated_frame_saved_pc (gdbarch, vax_frame_saved_pc);
 401
 402   set_gdbarch_frame_args_address (gdbarch, vax_frame_args_address);
 403   set_gdbarch_frame_locals_address (gdbarch, vax_frame_locals_address);
 404
 405   set_gdbarch_deprecated_frame_init_saved_regs (gdbarch, vax_frame_init_saved_regs);
 406
 407   set_gdbarch_frame_args_skip (gdbarch, 4);
 408
 409   set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
 410
 411   /* Return value info */
 412   set_gdbarch_deprecated_store_struct_return (gdbarch, vax_store_struct_return);
 413   set_gdbarch_deprecated_extract_return_value (gdbarch, vax_extract_return_value);
 414   set_gdbarch_deprecated_store_return_value (gdbarch, vax_store_return_value);
 415   set_gdbarch_deprecated_extract_struct_value_address (gdbarch, vax_extract_struct_value_address);
 416
 417   /* Call dummy info */
 418   set_gdbarch_deprecated_push_dummy_frame (gdbarch, vax_push_dummy_frame);
 419   set_gdbarch_deprecated_pop_frame (gdbarch, vax_pop_frame);
 420   set_gdbarch_call_dummy_location (gdbarch, ON_STACK);
 421   set_gdbarch_deprecated_call_dummy_words (gdbarch, vax_call_dummy_words);
 422   set_gdbarch_deprecated_sizeof_call_dummy_words (gdbarch, sizeof_vax_call_dummy_words);
 423   set_gdbarch_deprecated_fix_call_dummy (gdbarch, vax_fix_call_dummy);
 424   set_gdbarch_deprecated_call_dummy_breakpoint_offset (gdbarch, 7);
 425   set_gdbarch_deprecated_use_generic_dummy_frames (gdbarch, 0);
 426   set_gdbarch_deprecated_pc_in_call_dummy (gdbarch, deprecated_pc_in_call_dummy_on_stack);
 427
 428   /* Breakpoint info */
 429   set_gdbarch_breakpoint_from_pc (gdbarch, vax_breakpoint_from_pc);
 430   set_gdbarch_decr_pc_after_break (gdbarch, 0);
 431
 432   /* Misc info */
 433   set_gdbarch_function_start_offset (gdbarch, 2);
 434   set_gdbarch_believe_pcc_promotion (gdbarch, 1);
 435
 436   /* Should be using push_dummy_call.  */
 437   set_gdbarch_deprecated_dummy_write_sp (gdbarch, generic_target_write_sp);
 438
 439   /* Hook in ABI-specific overrides, if they have been registered.  */
 440   gdbarch_init_osabi (info, gdbarch);
 441
 442   set_gdbarch_print_insn (gdbarch, print_insn_vax);
 443
 444   return (gdbarch);
 445 }
 446
 447 void
 448 _initialize_vax_tdep (void)
 449 {
 450   gdbarch_register (bfd_arch_vax, vax_gdbarch_init, NULL);
 451 }