| 1 | /* Target-dependent code for the VAX. |
| 2 | |
| 3 | Copyright 1986, 1989, 1991, 1992, 1995, 1996, 1998, 1999, 2000, |
| 4 | 2002, 2003, 2004 Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 2 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program; if not, write to the Free Software |
| 20 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 21 | Boston, MA 02111-1307, USA. */ |
| 22 | |
| 23 | #include "defs.h" |
| 24 | #include "arch-utils.h" |
| 25 | #include "dis-asm.h" |
| 26 | #include "frame.h" |
| 27 | #include "frame-base.h" |
| 28 | #include "frame-unwind.h" |
| 29 | #include "gdbcore.h" |
| 30 | #include "gdbtypes.h" |
| 31 | #include "osabi.h" |
| 32 | #include "regcache.h" |
| 33 | #include "regset.h" |
| 34 | #include "trad-frame.h" |
| 35 | #include "value.h" |
| 36 | |
| 37 | #include "gdb_string.h" |
| 38 | |
| 39 | #include "vax-tdep.h" |
| 40 | |
| 41 | /* Return the name of register REGNUM. */ |
| 42 | |
| 43 | static const char * |
| 44 | vax_register_name (int regnum) |
| 45 | { |
| 46 | static char *register_names[] = |
| 47 | { |
| 48 | "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", |
| 49 | "r8", "r9", "r10", "r11", "ap", "fp", "sp", "pc", |
| 50 | "ps", |
| 51 | }; |
| 52 | |
| 53 | if (regnum >= 0 && regnum < ARRAY_SIZE (register_names)) |
| 54 | return register_names[regnum]; |
| 55 | |
| 56 | return NULL; |
| 57 | } |
| 58 | |
| 59 | /* Return the GDB type object for the "standard" data type of data in |
| 60 | register REGNUM. */ |
| 61 | |
| 62 | static struct type * |
| 63 | vax_register_type (struct gdbarch *gdbarch, int regnum) |
| 64 | { |
| 65 | return builtin_type_int; |
| 66 | } |
| 67 | \f |
| 68 | /* Core file support. */ |
| 69 | |
| 70 | /* Supply register REGNUM from the buffer specified by GREGS and LEN |
| 71 | in the general-purpose register set REGSET to register cache |
| 72 | REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */ |
| 73 | |
| 74 | static void |
| 75 | vax_supply_gregset (const struct regset *regset, struct regcache *regcache, |
| 76 | int regnum, const void *gregs, size_t len) |
| 77 | { |
| 78 | const char *regs = gregs; |
| 79 | int i; |
| 80 | |
| 81 | for (i = 0; i < VAX_NUM_REGS; i++) |
| 82 | { |
| 83 | if (regnum == i || regnum == -1) |
| 84 | regcache_raw_supply (regcache, i, regs + i * 4); |
| 85 | } |
| 86 | } |
| 87 | |
| 88 | /* VAX register set. */ |
| 89 | |
| 90 | static struct regset vax_gregset = |
| 91 | { |
| 92 | NULL, |
| 93 | vax_supply_gregset |
| 94 | }; |
| 95 | |
| 96 | /* Return the appropriate register set for the core section identified |
| 97 | by SECT_NAME and SECT_SIZE. */ |
| 98 | |
| 99 | static const struct regset * |
| 100 | vax_regset_from_core_section (struct gdbarch *gdbarch, |
| 101 | const char *sect_name, size_t sect_size) |
| 102 | { |
| 103 | if (strcmp (sect_name, ".reg") == 0 && sect_size >= VAX_NUM_REGS * 4) |
| 104 | return &vax_gregset; |
| 105 | |
| 106 | return NULL; |
| 107 | } |
| 108 | \f |
| 109 | /* The VAX Unix calling convention uses R1 to pass a structure return |
| 110 | value address instead of passing it as a first (hidden) argument as |
| 111 | the VMS calling convention suggests. */ |
| 112 | |
| 113 | static CORE_ADDR |
| 114 | vax_store_arguments (struct regcache *regcache, int nargs, |
| 115 | struct value **args, CORE_ADDR sp) |
| 116 | { |
| 117 | char buf[4]; |
| 118 | int count = 0; |
| 119 | int i; |
| 120 | |
| 121 | /* We create an argument list on the stack, and make the argument |
| 122 | pointer to it. */ |
| 123 | |
| 124 | /* Push arguments in reverse order. */ |
| 125 | for (i = nargs - 1; i >= 0; i--) |
| 126 | { |
| 127 | int len = TYPE_LENGTH (VALUE_ENCLOSING_TYPE (args[i])); |
| 128 | |
| 129 | sp -= (len + 3) & ~3; |
| 130 | count += (len + 3) / 4; |
| 131 | write_memory (sp, VALUE_CONTENTS_ALL (args[i]), len); |
| 132 | } |
| 133 | |
| 134 | /* Push argument count. */ |
| 135 | sp -= 4; |
| 136 | store_unsigned_integer (buf, 4, count); |
| 137 | write_memory (sp, buf, 4); |
| 138 | |
| 139 | /* Update the argument pointer. */ |
| 140 | store_unsigned_integer (buf, 4, sp); |
| 141 | regcache_cooked_write (regcache, VAX_AP_REGNUM, buf); |
| 142 | |
| 143 | return sp; |
| 144 | } |
| 145 | |
| 146 | static CORE_ADDR |
| 147 | vax_push_dummy_call (struct gdbarch *gdbarch, struct value *function, |
| 148 | struct regcache *regcache, CORE_ADDR bp_addr, int nargs, |
| 149 | struct value **args, CORE_ADDR sp, int struct_return, |
| 150 | CORE_ADDR struct_addr) |
| 151 | { |
| 152 | CORE_ADDR fp = sp; |
| 153 | char buf[4]; |
| 154 | |
| 155 | /* Set up the function arguments. */ |
| 156 | sp = vax_store_arguments (regcache, nargs, args, sp); |
| 157 | |
| 158 | /* Store return value address. */ |
| 159 | if (struct_return) |
| 160 | regcache_cooked_write_unsigned (regcache, VAX_R1_REGNUM, struct_addr); |
| 161 | |
| 162 | /* Store return address in the PC slot. */ |
| 163 | sp -= 4; |
| 164 | store_unsigned_integer (buf, 4, bp_addr); |
| 165 | write_memory (sp, buf, 4); |
| 166 | |
| 167 | /* Store the (fake) frame pointer in the FP slot. */ |
| 168 | sp -= 4; |
| 169 | store_unsigned_integer (buf, 4, fp); |
| 170 | write_memory (sp, buf, 4); |
| 171 | |
| 172 | /* Skip the AP slot. */ |
| 173 | sp -= 4; |
| 174 | |
| 175 | /* Store register save mask and control bits. */ |
| 176 | sp -= 4; |
| 177 | store_unsigned_integer (buf, 4, 0); |
| 178 | write_memory (sp, buf, 4); |
| 179 | |
| 180 | /* Store condition handler. */ |
| 181 | sp -= 4; |
| 182 | store_unsigned_integer (buf, 4, 0); |
| 183 | write_memory (sp, buf, 4); |
| 184 | |
| 185 | /* Update the stack pointer and frame pointer. */ |
| 186 | store_unsigned_integer (buf, 4, sp); |
| 187 | regcache_cooked_write (regcache, VAX_SP_REGNUM, buf); |
| 188 | regcache_cooked_write (regcache, VAX_FP_REGNUM, buf); |
| 189 | |
| 190 | /* Return the saved (fake) frame pointer. */ |
| 191 | return fp; |
| 192 | } |
| 193 | |
| 194 | static struct frame_id |
| 195 | vax_unwind_dummy_id (struct gdbarch *gdbarch, struct frame_info *next_frame) |
| 196 | { |
| 197 | CORE_ADDR fp; |
| 198 | |
| 199 | fp = frame_unwind_register_unsigned (next_frame, VAX_FP_REGNUM); |
| 200 | return frame_id_build (fp, frame_pc_unwind (next_frame)); |
| 201 | } |
| 202 | \f |
| 203 | |
| 204 | static enum return_value_convention |
| 205 | vax_return_value (struct gdbarch *gdbarch, struct type *type, |
| 206 | struct regcache *regcache, void *readbuf, |
| 207 | const void *writebuf) |
| 208 | { |
| 209 | int len = TYPE_LENGTH (type); |
| 210 | char buf[8]; |
| 211 | |
| 212 | if (TYPE_CODE (type) == TYPE_CODE_STRUCT |
| 213 | || TYPE_CODE (type) == TYPE_CODE_UNION |
| 214 | || TYPE_CODE (type) == TYPE_CODE_ARRAY) |
| 215 | { |
| 216 | /* The default on VAX is to return structures in static memory. |
| 217 | Consequently a function must return the address where we can |
| 218 | find the return value. */ |
| 219 | |
| 220 | if (readbuf) |
| 221 | { |
| 222 | ULONGEST addr; |
| 223 | |
| 224 | regcache_raw_read_unsigned (regcache, VAX_R0_REGNUM, &addr); |
| 225 | read_memory (addr, readbuf, len); |
| 226 | } |
| 227 | |
| 228 | return RETURN_VALUE_ABI_RETURNS_ADDRESS; |
| 229 | } |
| 230 | |
| 231 | if (readbuf) |
| 232 | { |
| 233 | /* Read the contents of R0 and (if necessary) R1. */ |
| 234 | regcache_cooked_read (regcache, VAX_R0_REGNUM, buf); |
| 235 | if (len > 4) |
| 236 | regcache_cooked_read (regcache, VAX_R1_REGNUM, buf + 4); |
| 237 | memcpy (readbuf, buf, len); |
| 238 | } |
| 239 | if (writebuf) |
| 240 | { |
| 241 | /* Read the contents to R0 and (if necessary) R1. */ |
| 242 | memcpy (buf, writebuf, len); |
| 243 | regcache_cooked_write (regcache, VAX_R0_REGNUM, buf); |
| 244 | if (len > 4) |
| 245 | regcache_cooked_write (regcache, VAX_R1_REGNUM, buf + 4); |
| 246 | } |
| 247 | |
| 248 | return RETURN_VALUE_REGISTER_CONVENTION; |
| 249 | } |
| 250 | \f |
| 251 | |
| 252 | /* Use the program counter to determine the contents and size of a |
| 253 | breakpoint instruction. Return a pointer to a string of bytes that |
| 254 | encode a breakpoint instruction, store the length of the string in |
| 255 | *LEN and optionally adjust *PC to point to the correct memory |
| 256 | location for inserting the breakpoint. */ |
| 257 | |
| 258 | static const unsigned char * |
| 259 | vax_breakpoint_from_pc (CORE_ADDR *pc, int *len) |
| 260 | { |
| 261 | static unsigned char break_insn[] = { 3 }; |
| 262 | |
| 263 | *len = sizeof (break_insn); |
| 264 | return break_insn; |
| 265 | } |
| 266 | \f |
| 267 | /* Advance PC across any function entry prologue instructions |
| 268 | to reach some "real" code. */ |
| 269 | |
| 270 | static CORE_ADDR |
| 271 | vax_skip_prologue (CORE_ADDR pc) |
| 272 | { |
| 273 | unsigned char op = read_memory_unsigned_integer (pc, 1); |
| 274 | |
| 275 | if (op == 0x11) |
| 276 | pc += 2; /* skip brb */ |
| 277 | if (op == 0x31) |
| 278 | pc += 3; /* skip brw */ |
| 279 | if (op == 0xC2 |
| 280 | && (read_memory_unsigned_integer (pc + 2, 1)) == 0x5E) |
| 281 | pc += 3; /* skip subl2 */ |
| 282 | if (op == 0x9E |
| 283 | && (read_memory_unsigned_integer (pc + 1, 1)) == 0xAE |
| 284 | && (read_memory_unsigned_integer (pc + 3, 1)) == 0x5E) |
| 285 | pc += 4; /* skip movab */ |
| 286 | if (op == 0x9E |
| 287 | && (read_memory_unsigned_integer (pc + 1, 1)) == 0xCE |
| 288 | && (read_memory_unsigned_integer (pc + 4, 1)) == 0x5E) |
| 289 | pc += 5; /* skip movab */ |
| 290 | if (op == 0x9E |
| 291 | && (read_memory_unsigned_integer (pc + 1, 1)) == 0xEE |
| 292 | && (read_memory_unsigned_integer (pc + 6, 1)) == 0x5E) |
| 293 | pc += 7; /* skip movab */ |
| 294 | |
| 295 | return pc; |
| 296 | } |
| 297 | \f |
| 298 | |
| 299 | /* Unwinding the stack is relatively easy since the VAX has a |
| 300 | dedicated frame pointer, and frames are set up automatically as the |
| 301 | result of a function call. Most of the relevant information can be |
| 302 | inferred from the documentation of the Procedure Call Instructions |
| 303 | in the VAX MACRO and Instruction Set Reference Manual. */ |
| 304 | |
| 305 | struct vax_frame_cache |
| 306 | { |
| 307 | /* Base address. */ |
| 308 | CORE_ADDR base; |
| 309 | |
| 310 | /* Table of saved registers. */ |
| 311 | struct trad_frame_saved_reg *saved_regs; |
| 312 | }; |
| 313 | |
| 314 | struct vax_frame_cache * |
| 315 | vax_frame_cache (struct frame_info *next_frame, void **this_cache) |
| 316 | { |
| 317 | struct vax_frame_cache *cache; |
| 318 | CORE_ADDR addr; |
| 319 | ULONGEST mask; |
| 320 | int regnum; |
| 321 | |
| 322 | if (*this_cache) |
| 323 | return *this_cache; |
| 324 | |
| 325 | /* Allocate a new cache. */ |
| 326 | cache = FRAME_OBSTACK_ZALLOC (struct vax_frame_cache); |
| 327 | cache->saved_regs = trad_frame_alloc_saved_regs (next_frame); |
| 328 | |
| 329 | /* The frame pointer is used as the base for the frame. */ |
| 330 | cache->base = frame_unwind_register_unsigned (next_frame, VAX_FP_REGNUM); |
| 331 | if (cache->base == 0) |
| 332 | return cache; |
| 333 | |
| 334 | /* The register save mask and control bits determine the layout of |
| 335 | the stack frame. */ |
| 336 | mask = get_frame_memory_unsigned (next_frame, cache->base + 4, 4) >> 16; |
| 337 | |
| 338 | /* These are always saved. */ |
| 339 | cache->saved_regs[VAX_PC_REGNUM].addr = cache->base + 16; |
| 340 | cache->saved_regs[VAX_FP_REGNUM].addr = cache->base + 12; |
| 341 | cache->saved_regs[VAX_AP_REGNUM].addr = cache->base + 8; |
| 342 | cache->saved_regs[VAX_PS_REGNUM].addr = cache->base + 4; |
| 343 | |
| 344 | /* Scan the register save mask and record the location of the saved |
| 345 | registers. */ |
| 346 | addr = cache->base + 20; |
| 347 | for (regnum = 0; regnum < VAX_AP_REGNUM; regnum++) |
| 348 | { |
| 349 | if (mask & (1 << regnum)) |
| 350 | { |
| 351 | cache->saved_regs[regnum].addr = addr; |
| 352 | addr += 4; |
| 353 | } |
| 354 | } |
| 355 | |
| 356 | /* The CALLS/CALLG flag determines whether this frame has a General |
| 357 | Argument List or a Stack Argument List. */ |
| 358 | if (mask & (1 << 13)) |
| 359 | { |
| 360 | ULONGEST numarg; |
| 361 | |
| 362 | /* This is a procedure with Stack Argument List. Adjust the |
| 363 | stack address for the arguments that were pushed onto the |
| 364 | stack. The return instruction will automatically pop the |
| 365 | arguments from the stack. */ |
| 366 | numarg = get_frame_memory_unsigned (next_frame, addr, 1); |
| 367 | addr += 4 + numarg * 4; |
| 368 | } |
| 369 | |
| 370 | /* Bits 1:0 of the stack pointer were saved in the control bits. */ |
| 371 | trad_frame_set_value (cache->saved_regs, VAX_SP_REGNUM, addr + (mask >> 14)); |
| 372 | |
| 373 | return cache; |
| 374 | } |
| 375 | |
| 376 | static void |
| 377 | vax_frame_this_id (struct frame_info *next_frame, void **this_cache, |
| 378 | struct frame_id *this_id) |
| 379 | { |
| 380 | struct vax_frame_cache *cache = vax_frame_cache (next_frame, this_cache); |
| 381 | |
| 382 | /* This marks the outermost frame. */ |
| 383 | if (cache->base == 0) |
| 384 | return; |
| 385 | |
| 386 | (*this_id) = frame_id_build (cache->base, frame_pc_unwind (next_frame)); |
| 387 | } |
| 388 | |
| 389 | static void |
| 390 | vax_frame_prev_register (struct frame_info *next_frame, void **this_cache, |
| 391 | int regnum, int *optimizedp, |
| 392 | enum lval_type *lvalp, CORE_ADDR *addrp, |
| 393 | int *realnump, void *valuep) |
| 394 | { |
| 395 | struct vax_frame_cache *cache = vax_frame_cache (next_frame, this_cache); |
| 396 | |
| 397 | trad_frame_prev_register (next_frame, cache->saved_regs, regnum, |
| 398 | optimizedp, lvalp, addrp, realnump, valuep); |
| 399 | } |
| 400 | |
| 401 | static const struct frame_unwind vax_frame_unwind = |
| 402 | { |
| 403 | NORMAL_FRAME, |
| 404 | vax_frame_this_id, |
| 405 | vax_frame_prev_register |
| 406 | }; |
| 407 | |
| 408 | static const struct frame_unwind * |
| 409 | vax_frame_sniffer (struct frame_info *next_frame) |
| 410 | { |
| 411 | return &vax_frame_unwind; |
| 412 | } |
| 413 | \f |
| 414 | |
| 415 | static CORE_ADDR |
| 416 | vax_frame_base_address (struct frame_info *next_frame, void **this_cache) |
| 417 | { |
| 418 | struct vax_frame_cache *cache = vax_frame_cache (next_frame, this_cache); |
| 419 | |
| 420 | return cache->base; |
| 421 | } |
| 422 | |
| 423 | static CORE_ADDR |
| 424 | vax_frame_args_address (struct frame_info *next_frame, void **this_cache) |
| 425 | { |
| 426 | return frame_unwind_register_unsigned (next_frame, VAX_AP_REGNUM); |
| 427 | } |
| 428 | |
| 429 | static const struct frame_base vax_frame_base = |
| 430 | { |
| 431 | &vax_frame_unwind, |
| 432 | vax_frame_base_address, |
| 433 | vax_frame_base_address, |
| 434 | vax_frame_args_address |
| 435 | }; |
| 436 | |
| 437 | /* Return number of arguments for FRAME. */ |
| 438 | |
| 439 | static int |
| 440 | vax_frame_num_args (struct frame_info *frame) |
| 441 | { |
| 442 | CORE_ADDR args; |
| 443 | |
| 444 | /* Assume that the argument pointer for the outermost frame is |
| 445 | hosed, as is the case on NetBSD/vax ELF. */ |
| 446 | if (get_frame_base_address (frame) == 0) |
| 447 | return 0; |
| 448 | |
| 449 | args = get_frame_register_unsigned (frame, VAX_AP_REGNUM); |
| 450 | return get_frame_memory_unsigned (frame, args, 1); |
| 451 | } |
| 452 | |
| 453 | static CORE_ADDR |
| 454 | vax_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame) |
| 455 | { |
| 456 | return frame_unwind_register_unsigned (next_frame, VAX_PC_REGNUM); |
| 457 | } |
| 458 | \f |
| 459 | |
| 460 | /* Initialize the current architecture based on INFO. If possible, re-use an |
| 461 | architecture from ARCHES, which is a list of architectures already created |
| 462 | during this debugging session. |
| 463 | |
| 464 | Called e.g. at program startup, when reading a core file, and when reading |
| 465 | a binary file. */ |
| 466 | |
| 467 | static struct gdbarch * |
| 468 | vax_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) |
| 469 | { |
| 470 | struct gdbarch *gdbarch; |
| 471 | |
| 472 | /* If there is already a candidate, use it. */ |
| 473 | arches = gdbarch_list_lookup_by_info (arches, &info); |
| 474 | if (arches != NULL) |
| 475 | return arches->gdbarch; |
| 476 | |
| 477 | gdbarch = gdbarch_alloc (&info, NULL); |
| 478 | |
| 479 | /* Register info */ |
| 480 | set_gdbarch_num_regs (gdbarch, VAX_NUM_REGS); |
| 481 | set_gdbarch_register_name (gdbarch, vax_register_name); |
| 482 | set_gdbarch_register_type (gdbarch, vax_register_type); |
| 483 | set_gdbarch_sp_regnum (gdbarch, VAX_SP_REGNUM); |
| 484 | set_gdbarch_pc_regnum (gdbarch, VAX_PC_REGNUM); |
| 485 | set_gdbarch_ps_regnum (gdbarch, VAX_PS_REGNUM); |
| 486 | |
| 487 | set_gdbarch_regset_from_core_section |
| 488 | (gdbarch, vax_regset_from_core_section); |
| 489 | |
| 490 | /* Frame and stack info */ |
| 491 | set_gdbarch_skip_prologue (gdbarch, vax_skip_prologue); |
| 492 | set_gdbarch_frame_num_args (gdbarch, vax_frame_num_args); |
| 493 | set_gdbarch_frame_args_skip (gdbarch, 4); |
| 494 | |
| 495 | /* Stack grows downward. */ |
| 496 | set_gdbarch_inner_than (gdbarch, core_addr_lessthan); |
| 497 | |
| 498 | /* Return value info */ |
| 499 | set_gdbarch_return_value (gdbarch, vax_return_value); |
| 500 | |
| 501 | /* Call dummy code. */ |
| 502 | set_gdbarch_push_dummy_call (gdbarch, vax_push_dummy_call); |
| 503 | set_gdbarch_unwind_dummy_id (gdbarch, vax_unwind_dummy_id); |
| 504 | |
| 505 | /* Breakpoint info */ |
| 506 | set_gdbarch_breakpoint_from_pc (gdbarch, vax_breakpoint_from_pc); |
| 507 | |
| 508 | /* Misc info */ |
| 509 | set_gdbarch_deprecated_function_start_offset (gdbarch, 2); |
| 510 | set_gdbarch_believe_pcc_promotion (gdbarch, 1); |
| 511 | |
| 512 | set_gdbarch_print_insn (gdbarch, print_insn_vax); |
| 513 | |
| 514 | set_gdbarch_unwind_pc (gdbarch, vax_unwind_pc); |
| 515 | |
| 516 | frame_base_set_default (gdbarch, &vax_frame_base); |
| 517 | |
| 518 | /* Hook in ABI-specific overrides, if they have been registered. */ |
| 519 | gdbarch_init_osabi (info, gdbarch); |
| 520 | |
| 521 | frame_unwind_append_sniffer (gdbarch, vax_frame_sniffer); |
| 522 | |
| 523 | return (gdbarch); |
| 524 | } |
| 525 | |
| 526 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 527 | void _initialize_vax_tdep (void); |
| 528 | |
| 529 | void |
| 530 | _initialize_vax_tdep (void) |
| 531 | { |
| 532 | gdbarch_register (bfd_arch_vax, vax_gdbarch_init, NULL); |
| 533 | } |