| 1 | /* Target-dependent code for the VAX. |
| 2 | |
| 3 | Copyright (C) 1986-2015 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 | #include "arch-utils.h" |
| 22 | #include "dis-asm.h" |
| 23 | #include "floatformat.h" |
| 24 | #include "frame.h" |
| 25 | #include "frame-base.h" |
| 26 | #include "frame-unwind.h" |
| 27 | #include "gdbcore.h" |
| 28 | #include "gdbtypes.h" |
| 29 | #include "osabi.h" |
| 30 | #include "regcache.h" |
| 31 | #include "regset.h" |
| 32 | #include "trad-frame.h" |
| 33 | #include "value.h" |
| 34 | |
| 35 | #include "vax-tdep.h" |
| 36 | |
| 37 | /* Return the name of register REGNUM. */ |
| 38 | |
| 39 | static const char * |
| 40 | vax_register_name (struct gdbarch *gdbarch, int regnum) |
| 41 | { |
| 42 | static char *register_names[] = |
| 43 | { |
| 44 | "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", |
| 45 | "r8", "r9", "r10", "r11", "ap", "fp", "sp", "pc", |
| 46 | "ps", |
| 47 | }; |
| 48 | |
| 49 | if (regnum >= 0 && regnum < ARRAY_SIZE (register_names)) |
| 50 | return register_names[regnum]; |
| 51 | |
| 52 | return NULL; |
| 53 | } |
| 54 | |
| 55 | /* Return the GDB type object for the "standard" data type of data in |
| 56 | register REGNUM. */ |
| 57 | |
| 58 | static struct type * |
| 59 | vax_register_type (struct gdbarch *gdbarch, int regnum) |
| 60 | { |
| 61 | return builtin_type (gdbarch)->builtin_int; |
| 62 | } |
| 63 | \f |
| 64 | /* Core file support. */ |
| 65 | |
| 66 | /* Supply register REGNUM from the buffer specified by GREGS and LEN |
| 67 | in the general-purpose register set REGSET to register cache |
| 68 | REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */ |
| 69 | |
| 70 | static void |
| 71 | vax_supply_gregset (const struct regset *regset, struct regcache *regcache, |
| 72 | int regnum, const void *gregs, size_t len) |
| 73 | { |
| 74 | const gdb_byte *regs = (const gdb_byte *) gregs; |
| 75 | int i; |
| 76 | |
| 77 | for (i = 0; i < VAX_NUM_REGS; i++) |
| 78 | { |
| 79 | if (regnum == i || regnum == -1) |
| 80 | regcache_raw_supply (regcache, i, regs + i * 4); |
| 81 | } |
| 82 | } |
| 83 | |
| 84 | /* VAX register set. */ |
| 85 | |
| 86 | static const struct regset vax_gregset = |
| 87 | { |
| 88 | NULL, |
| 89 | vax_supply_gregset |
| 90 | }; |
| 91 | |
| 92 | /* Iterate over core file register note sections. */ |
| 93 | |
| 94 | static void |
| 95 | vax_iterate_over_regset_sections (struct gdbarch *gdbarch, |
| 96 | iterate_over_regset_sections_cb *cb, |
| 97 | void *cb_data, |
| 98 | const struct regcache *regcache) |
| 99 | { |
| 100 | cb (".reg", VAX_NUM_REGS * 4, &vax_gregset, NULL, cb_data); |
| 101 | } |
| 102 | \f |
| 103 | /* The VAX UNIX calling convention uses R1 to pass a structure return |
| 104 | value address instead of passing it as a first (hidden) argument as |
| 105 | the VMS calling convention suggests. */ |
| 106 | |
| 107 | static CORE_ADDR |
| 108 | vax_store_arguments (struct regcache *regcache, int nargs, |
| 109 | struct value **args, CORE_ADDR sp) |
| 110 | { |
| 111 | struct gdbarch *gdbarch = get_regcache_arch (regcache); |
| 112 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 113 | gdb_byte buf[4]; |
| 114 | int count = 0; |
| 115 | int i; |
| 116 | |
| 117 | /* We create an argument list on the stack, and make the argument |
| 118 | pointer to it. */ |
| 119 | |
| 120 | /* Push arguments in reverse order. */ |
| 121 | for (i = nargs - 1; i >= 0; i--) |
| 122 | { |
| 123 | int len = TYPE_LENGTH (value_enclosing_type (args[i])); |
| 124 | |
| 125 | sp -= (len + 3) & ~3; |
| 126 | count += (len + 3) / 4; |
| 127 | write_memory (sp, value_contents_all (args[i]), len); |
| 128 | } |
| 129 | |
| 130 | /* Push argument count. */ |
| 131 | sp -= 4; |
| 132 | store_unsigned_integer (buf, 4, byte_order, count); |
| 133 | write_memory (sp, buf, 4); |
| 134 | |
| 135 | /* Update the argument pointer. */ |
| 136 | store_unsigned_integer (buf, 4, byte_order, sp); |
| 137 | regcache_cooked_write (regcache, VAX_AP_REGNUM, buf); |
| 138 | |
| 139 | return sp; |
| 140 | } |
| 141 | |
| 142 | static CORE_ADDR |
| 143 | vax_push_dummy_call (struct gdbarch *gdbarch, struct value *function, |
| 144 | struct regcache *regcache, CORE_ADDR bp_addr, int nargs, |
| 145 | struct value **args, CORE_ADDR sp, int struct_return, |
| 146 | CORE_ADDR struct_addr) |
| 147 | { |
| 148 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 149 | CORE_ADDR fp = sp; |
| 150 | gdb_byte buf[4]; |
| 151 | |
| 152 | /* Set up the function arguments. */ |
| 153 | sp = vax_store_arguments (regcache, nargs, args, sp); |
| 154 | |
| 155 | /* Store return value address. */ |
| 156 | if (struct_return) |
| 157 | regcache_cooked_write_unsigned (regcache, VAX_R1_REGNUM, struct_addr); |
| 158 | |
| 159 | /* Store return address in the PC slot. */ |
| 160 | sp -= 4; |
| 161 | store_unsigned_integer (buf, 4, byte_order, bp_addr); |
| 162 | write_memory (sp, buf, 4); |
| 163 | |
| 164 | /* Store the (fake) frame pointer in the FP slot. */ |
| 165 | sp -= 4; |
| 166 | store_unsigned_integer (buf, 4, byte_order, fp); |
| 167 | write_memory (sp, buf, 4); |
| 168 | |
| 169 | /* Skip the AP slot. */ |
| 170 | sp -= 4; |
| 171 | |
| 172 | /* Store register save mask and control bits. */ |
| 173 | sp -= 4; |
| 174 | store_unsigned_integer (buf, 4, byte_order, 0); |
| 175 | write_memory (sp, buf, 4); |
| 176 | |
| 177 | /* Store condition handler. */ |
| 178 | sp -= 4; |
| 179 | store_unsigned_integer (buf, 4, byte_order, 0); |
| 180 | write_memory (sp, buf, 4); |
| 181 | |
| 182 | /* Update the stack pointer and frame pointer. */ |
| 183 | store_unsigned_integer (buf, 4, byte_order, sp); |
| 184 | regcache_cooked_write (regcache, VAX_SP_REGNUM, buf); |
| 185 | regcache_cooked_write (regcache, VAX_FP_REGNUM, buf); |
| 186 | |
| 187 | /* Return the saved (fake) frame pointer. */ |
| 188 | return fp; |
| 189 | } |
| 190 | |
| 191 | static struct frame_id |
| 192 | vax_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame) |
| 193 | { |
| 194 | CORE_ADDR fp; |
| 195 | |
| 196 | fp = get_frame_register_unsigned (this_frame, VAX_FP_REGNUM); |
| 197 | return frame_id_build (fp, get_frame_pc (this_frame)); |
| 198 | } |
| 199 | \f |
| 200 | |
| 201 | static enum return_value_convention |
| 202 | vax_return_value (struct gdbarch *gdbarch, struct value *function, |
| 203 | struct type *type, struct regcache *regcache, |
| 204 | gdb_byte *readbuf, const gdb_byte *writebuf) |
| 205 | { |
| 206 | int len = TYPE_LENGTH (type); |
| 207 | gdb_byte buf[8]; |
| 208 | |
| 209 | if (TYPE_CODE (type) == TYPE_CODE_STRUCT |
| 210 | || TYPE_CODE (type) == TYPE_CODE_UNION |
| 211 | || TYPE_CODE (type) == TYPE_CODE_ARRAY) |
| 212 | { |
| 213 | /* The default on VAX is to return structures in static memory. |
| 214 | Consequently a function must return the address where we can |
| 215 | find the return value. */ |
| 216 | |
| 217 | if (readbuf) |
| 218 | { |
| 219 | ULONGEST addr; |
| 220 | |
| 221 | regcache_raw_read_unsigned (regcache, VAX_R0_REGNUM, &addr); |
| 222 | read_memory (addr, readbuf, len); |
| 223 | } |
| 224 | |
| 225 | return RETURN_VALUE_ABI_RETURNS_ADDRESS; |
| 226 | } |
| 227 | |
| 228 | if (readbuf) |
| 229 | { |
| 230 | /* Read the contents of R0 and (if necessary) R1. */ |
| 231 | regcache_cooked_read (regcache, VAX_R0_REGNUM, buf); |
| 232 | if (len > 4) |
| 233 | regcache_cooked_read (regcache, VAX_R1_REGNUM, buf + 4); |
| 234 | memcpy (readbuf, buf, len); |
| 235 | } |
| 236 | if (writebuf) |
| 237 | { |
| 238 | /* Read the contents to R0 and (if necessary) R1. */ |
| 239 | memcpy (buf, writebuf, len); |
| 240 | regcache_cooked_write (regcache, VAX_R0_REGNUM, buf); |
| 241 | if (len > 4) |
| 242 | regcache_cooked_write (regcache, VAX_R1_REGNUM, buf + 4); |
| 243 | } |
| 244 | |
| 245 | return RETURN_VALUE_REGISTER_CONVENTION; |
| 246 | } |
| 247 | \f |
| 248 | |
| 249 | /* Use the program counter to determine the contents and size of a |
| 250 | breakpoint instruction. Return a pointer to a string of bytes that |
| 251 | encode a breakpoint instruction, store the length of the string in |
| 252 | *LEN and optionally adjust *PC to point to the correct memory |
| 253 | location for inserting the breakpoint. */ |
| 254 | |
| 255 | static const gdb_byte * |
| 256 | vax_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pc, int *len) |
| 257 | { |
| 258 | static gdb_byte break_insn[] = { 3 }; |
| 259 | |
| 260 | *len = sizeof (break_insn); |
| 261 | return break_insn; |
| 262 | } |
| 263 | \f |
| 264 | /* Advance PC across any function entry prologue instructions |
| 265 | to reach some "real" code. */ |
| 266 | |
| 267 | static CORE_ADDR |
| 268 | vax_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc) |
| 269 | { |
| 270 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 271 | gdb_byte op = read_memory_unsigned_integer (pc, 1, byte_order); |
| 272 | |
| 273 | if (op == 0x11) |
| 274 | pc += 2; /* skip brb */ |
| 275 | if (op == 0x31) |
| 276 | pc += 3; /* skip brw */ |
| 277 | if (op == 0xC2 |
| 278 | && read_memory_unsigned_integer (pc + 2, 1, byte_order) == 0x5E) |
| 279 | pc += 3; /* skip subl2 */ |
| 280 | if (op == 0x9E |
| 281 | && read_memory_unsigned_integer (pc + 1, 1, byte_order) == 0xAE |
| 282 | && read_memory_unsigned_integer (pc + 3, 1, byte_order) == 0x5E) |
| 283 | pc += 4; /* skip movab */ |
| 284 | if (op == 0x9E |
| 285 | && read_memory_unsigned_integer (pc + 1, 1, byte_order) == 0xCE |
| 286 | && read_memory_unsigned_integer (pc + 4, 1, byte_order) == 0x5E) |
| 287 | pc += 5; /* skip movab */ |
| 288 | if (op == 0x9E |
| 289 | && read_memory_unsigned_integer (pc + 1, 1, byte_order) == 0xEE |
| 290 | && read_memory_unsigned_integer (pc + 6, 1, byte_order) == 0x5E) |
| 291 | pc += 7; /* skip movab */ |
| 292 | |
| 293 | return pc; |
| 294 | } |
| 295 | \f |
| 296 | |
| 297 | /* Unwinding the stack is relatively easy since the VAX has a |
| 298 | dedicated frame pointer, and frames are set up automatically as the |
| 299 | result of a function call. Most of the relevant information can be |
| 300 | inferred from the documentation of the Procedure Call Instructions |
| 301 | in the VAX MACRO and Instruction Set Reference Manual. */ |
| 302 | |
| 303 | struct vax_frame_cache |
| 304 | { |
| 305 | /* Base address. */ |
| 306 | CORE_ADDR base; |
| 307 | |
| 308 | /* Table of saved registers. */ |
| 309 | struct trad_frame_saved_reg *saved_regs; |
| 310 | }; |
| 311 | |
| 312 | static struct vax_frame_cache * |
| 313 | vax_frame_cache (struct frame_info *this_frame, void **this_cache) |
| 314 | { |
| 315 | struct vax_frame_cache *cache; |
| 316 | CORE_ADDR addr; |
| 317 | ULONGEST mask; |
| 318 | int regnum; |
| 319 | |
| 320 | if (*this_cache) |
| 321 | return (struct vax_frame_cache *) *this_cache; |
| 322 | |
| 323 | /* Allocate a new cache. */ |
| 324 | cache = FRAME_OBSTACK_ZALLOC (struct vax_frame_cache); |
| 325 | cache->saved_regs = trad_frame_alloc_saved_regs (this_frame); |
| 326 | |
| 327 | /* The frame pointer is used as the base for the frame. */ |
| 328 | cache->base = get_frame_register_unsigned (this_frame, VAX_FP_REGNUM); |
| 329 | if (cache->base == 0) |
| 330 | return cache; |
| 331 | |
| 332 | /* The register save mask and control bits determine the layout of |
| 333 | the stack frame. */ |
| 334 | mask = get_frame_memory_unsigned (this_frame, cache->base + 4, 4) >> 16; |
| 335 | |
| 336 | /* These are always saved. */ |
| 337 | cache->saved_regs[VAX_PC_REGNUM].addr = cache->base + 16; |
| 338 | cache->saved_regs[VAX_FP_REGNUM].addr = cache->base + 12; |
| 339 | cache->saved_regs[VAX_AP_REGNUM].addr = cache->base + 8; |
| 340 | cache->saved_regs[VAX_PS_REGNUM].addr = cache->base + 4; |
| 341 | |
| 342 | /* Scan the register save mask and record the location of the saved |
| 343 | registers. */ |
| 344 | addr = cache->base + 20; |
| 345 | for (regnum = 0; regnum < VAX_AP_REGNUM; regnum++) |
| 346 | { |
| 347 | if (mask & (1 << regnum)) |
| 348 | { |
| 349 | cache->saved_regs[regnum].addr = addr; |
| 350 | addr += 4; |
| 351 | } |
| 352 | } |
| 353 | |
| 354 | /* The CALLS/CALLG flag determines whether this frame has a General |
| 355 | Argument List or a Stack Argument List. */ |
| 356 | if (mask & (1 << 13)) |
| 357 | { |
| 358 | ULONGEST numarg; |
| 359 | |
| 360 | /* This is a procedure with Stack Argument List. Adjust the |
| 361 | stack address for the arguments that were pushed onto the |
| 362 | stack. The return instruction will automatically pop the |
| 363 | arguments from the stack. */ |
| 364 | numarg = get_frame_memory_unsigned (this_frame, addr, 1); |
| 365 | addr += 4 + numarg * 4; |
| 366 | } |
| 367 | |
| 368 | /* Bits 1:0 of the stack pointer were saved in the control bits. */ |
| 369 | trad_frame_set_value (cache->saved_regs, VAX_SP_REGNUM, addr + (mask >> 14)); |
| 370 | |
| 371 | return cache; |
| 372 | } |
| 373 | |
| 374 | static void |
| 375 | vax_frame_this_id (struct frame_info *this_frame, void **this_cache, |
| 376 | struct frame_id *this_id) |
| 377 | { |
| 378 | struct vax_frame_cache *cache = vax_frame_cache (this_frame, this_cache); |
| 379 | |
| 380 | /* This marks the outermost frame. */ |
| 381 | if (cache->base == 0) |
| 382 | return; |
| 383 | |
| 384 | (*this_id) = frame_id_build (cache->base, get_frame_func (this_frame)); |
| 385 | } |
| 386 | |
| 387 | static struct value * |
| 388 | vax_frame_prev_register (struct frame_info *this_frame, |
| 389 | void **this_cache, int regnum) |
| 390 | { |
| 391 | struct vax_frame_cache *cache = vax_frame_cache (this_frame, this_cache); |
| 392 | |
| 393 | return trad_frame_get_prev_register (this_frame, cache->saved_regs, regnum); |
| 394 | } |
| 395 | |
| 396 | static const struct frame_unwind vax_frame_unwind = |
| 397 | { |
| 398 | NORMAL_FRAME, |
| 399 | default_frame_unwind_stop_reason, |
| 400 | vax_frame_this_id, |
| 401 | vax_frame_prev_register, |
| 402 | NULL, |
| 403 | default_frame_sniffer |
| 404 | }; |
| 405 | \f |
| 406 | |
| 407 | static CORE_ADDR |
| 408 | vax_frame_base_address (struct frame_info *this_frame, void **this_cache) |
| 409 | { |
| 410 | struct vax_frame_cache *cache = vax_frame_cache (this_frame, this_cache); |
| 411 | |
| 412 | return cache->base; |
| 413 | } |
| 414 | |
| 415 | static CORE_ADDR |
| 416 | vax_frame_args_address (struct frame_info *this_frame, void **this_cache) |
| 417 | { |
| 418 | return get_frame_register_unsigned (this_frame, VAX_AP_REGNUM); |
| 419 | } |
| 420 | |
| 421 | static const struct frame_base vax_frame_base = |
| 422 | { |
| 423 | &vax_frame_unwind, |
| 424 | vax_frame_base_address, |
| 425 | vax_frame_base_address, |
| 426 | vax_frame_args_address |
| 427 | }; |
| 428 | |
| 429 | /* Return number of arguments for FRAME. */ |
| 430 | |
| 431 | static int |
| 432 | vax_frame_num_args (struct frame_info *frame) |
| 433 | { |
| 434 | CORE_ADDR args; |
| 435 | |
| 436 | /* Assume that the argument pointer for the outermost frame is |
| 437 | hosed, as is the case on NetBSD/vax ELF. */ |
| 438 | if (get_frame_base_address (frame) == 0) |
| 439 | return 0; |
| 440 | |
| 441 | args = get_frame_register_unsigned (frame, VAX_AP_REGNUM); |
| 442 | return get_frame_memory_unsigned (frame, args, 1); |
| 443 | } |
| 444 | |
| 445 | static CORE_ADDR |
| 446 | vax_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame) |
| 447 | { |
| 448 | return frame_unwind_register_unsigned (next_frame, VAX_PC_REGNUM); |
| 449 | } |
| 450 | \f |
| 451 | |
| 452 | /* Initialize the current architecture based on INFO. If possible, re-use an |
| 453 | architecture from ARCHES, which is a list of architectures already created |
| 454 | during this debugging session. |
| 455 | |
| 456 | Called e.g. at program startup, when reading a core file, and when reading |
| 457 | a binary file. */ |
| 458 | |
| 459 | static struct gdbarch * |
| 460 | vax_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) |
| 461 | { |
| 462 | struct gdbarch *gdbarch; |
| 463 | |
| 464 | /* If there is already a candidate, use it. */ |
| 465 | arches = gdbarch_list_lookup_by_info (arches, &info); |
| 466 | if (arches != NULL) |
| 467 | return arches->gdbarch; |
| 468 | |
| 469 | gdbarch = gdbarch_alloc (&info, NULL); |
| 470 | |
| 471 | set_gdbarch_float_format (gdbarch, floatformats_vax_f); |
| 472 | set_gdbarch_double_format (gdbarch, floatformats_vax_d); |
| 473 | set_gdbarch_long_double_format (gdbarch, floatformats_vax_d); |
| 474 | set_gdbarch_long_double_bit (gdbarch, 64); |
| 475 | |
| 476 | /* Register info */ |
| 477 | set_gdbarch_num_regs (gdbarch, VAX_NUM_REGS); |
| 478 | set_gdbarch_register_name (gdbarch, vax_register_name); |
| 479 | set_gdbarch_register_type (gdbarch, vax_register_type); |
| 480 | set_gdbarch_sp_regnum (gdbarch, VAX_SP_REGNUM); |
| 481 | set_gdbarch_pc_regnum (gdbarch, VAX_PC_REGNUM); |
| 482 | set_gdbarch_ps_regnum (gdbarch, VAX_PS_REGNUM); |
| 483 | |
| 484 | set_gdbarch_iterate_over_regset_sections |
| 485 | (gdbarch, vax_iterate_over_regset_sections); |
| 486 | |
| 487 | /* Frame and stack info */ |
| 488 | set_gdbarch_skip_prologue (gdbarch, vax_skip_prologue); |
| 489 | set_gdbarch_frame_num_args (gdbarch, vax_frame_num_args); |
| 490 | set_gdbarch_frame_args_skip (gdbarch, 4); |
| 491 | |
| 492 | /* Stack grows downward. */ |
| 493 | set_gdbarch_inner_than (gdbarch, core_addr_lessthan); |
| 494 | |
| 495 | /* Return value info */ |
| 496 | set_gdbarch_return_value (gdbarch, vax_return_value); |
| 497 | |
| 498 | /* Call dummy code. */ |
| 499 | set_gdbarch_push_dummy_call (gdbarch, vax_push_dummy_call); |
| 500 | set_gdbarch_dummy_id (gdbarch, vax_dummy_id); |
| 501 | |
| 502 | /* Breakpoint info */ |
| 503 | set_gdbarch_breakpoint_from_pc (gdbarch, vax_breakpoint_from_pc); |
| 504 | |
| 505 | /* Misc info */ |
| 506 | set_gdbarch_deprecated_function_start_offset (gdbarch, 2); |
| 507 | set_gdbarch_believe_pcc_promotion (gdbarch, 1); |
| 508 | |
| 509 | set_gdbarch_print_insn (gdbarch, print_insn_vax); |
| 510 | |
| 511 | set_gdbarch_unwind_pc (gdbarch, vax_unwind_pc); |
| 512 | |
| 513 | frame_base_set_default (gdbarch, &vax_frame_base); |
| 514 | |
| 515 | /* Hook in ABI-specific overrides, if they have been registered. */ |
| 516 | gdbarch_init_osabi (info, gdbarch); |
| 517 | |
| 518 | frame_unwind_append_unwinder (gdbarch, &vax_frame_unwind); |
| 519 | |
| 520 | return (gdbarch); |
| 521 | } |
| 522 | |
| 523 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 524 | void _initialize_vax_tdep (void); |
| 525 | |
| 526 | void |
| 527 | _initialize_vax_tdep (void) |
| 528 | { |
| 529 | gdbarch_register (bfd_arch_vax, vax_gdbarch_init, NULL); |
| 530 | } |