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