| 1 | /* DWARF 2 Expression Evaluator. |
| 2 | |
| 3 | Copyright (C) 2001, 2002, 2003, 2005, 2007, 2008, 2009, 2010, 2011 |
| 4 | Free Software Foundation, Inc. |
| 5 | |
| 6 | Contributed by Daniel Berlin (dan@dberlin.org) |
| 7 | |
| 8 | This file is part of GDB. |
| 9 | |
| 10 | This program is free software; you can redistribute it and/or modify |
| 11 | it under the terms of the GNU General Public License as published by |
| 12 | the Free Software Foundation; either version 3 of the License, or |
| 13 | (at your option) any later version. |
| 14 | |
| 15 | This program is distributed in the hope that it will be useful, |
| 16 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | GNU General Public License for more details. |
| 19 | |
| 20 | You should have received a copy of the GNU General Public License |
| 21 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 22 | |
| 23 | #include "defs.h" |
| 24 | #include "symtab.h" |
| 25 | #include "gdbtypes.h" |
| 26 | #include "value.h" |
| 27 | #include "gdbcore.h" |
| 28 | #include "dwarf2.h" |
| 29 | #include "dwarf2expr.h" |
| 30 | #include "gdb_assert.h" |
| 31 | |
| 32 | /* Local prototypes. */ |
| 33 | |
| 34 | static void execute_stack_op (struct dwarf_expr_context *, |
| 35 | const gdb_byte *, const gdb_byte *); |
| 36 | |
| 37 | /* Create a new context for the expression evaluator. */ |
| 38 | |
| 39 | struct dwarf_expr_context * |
| 40 | new_dwarf_expr_context (void) |
| 41 | { |
| 42 | struct dwarf_expr_context *retval; |
| 43 | |
| 44 | retval = xcalloc (1, sizeof (struct dwarf_expr_context)); |
| 45 | retval->stack_len = 0; |
| 46 | retval->stack_allocated = 10; |
| 47 | retval->stack = xmalloc (retval->stack_allocated |
| 48 | * sizeof (struct dwarf_stack_value)); |
| 49 | retval->num_pieces = 0; |
| 50 | retval->pieces = 0; |
| 51 | retval->max_recursion_depth = 0x100; |
| 52 | return retval; |
| 53 | } |
| 54 | |
| 55 | /* Release the memory allocated to CTX. */ |
| 56 | |
| 57 | void |
| 58 | free_dwarf_expr_context (struct dwarf_expr_context *ctx) |
| 59 | { |
| 60 | xfree (ctx->stack); |
| 61 | xfree (ctx->pieces); |
| 62 | xfree (ctx); |
| 63 | } |
| 64 | |
| 65 | /* Helper for make_cleanup_free_dwarf_expr_context. */ |
| 66 | |
| 67 | static void |
| 68 | free_dwarf_expr_context_cleanup (void *arg) |
| 69 | { |
| 70 | free_dwarf_expr_context (arg); |
| 71 | } |
| 72 | |
| 73 | /* Return a cleanup that calls free_dwarf_expr_context. */ |
| 74 | |
| 75 | struct cleanup * |
| 76 | make_cleanup_free_dwarf_expr_context (struct dwarf_expr_context *ctx) |
| 77 | { |
| 78 | return make_cleanup (free_dwarf_expr_context_cleanup, ctx); |
| 79 | } |
| 80 | |
| 81 | /* Expand the memory allocated to CTX's stack to contain at least |
| 82 | NEED more elements than are currently used. */ |
| 83 | |
| 84 | static void |
| 85 | dwarf_expr_grow_stack (struct dwarf_expr_context *ctx, size_t need) |
| 86 | { |
| 87 | if (ctx->stack_len + need > ctx->stack_allocated) |
| 88 | { |
| 89 | size_t newlen = ctx->stack_len + need + 10; |
| 90 | |
| 91 | ctx->stack = xrealloc (ctx->stack, |
| 92 | newlen * sizeof (struct dwarf_stack_value)); |
| 93 | ctx->stack_allocated = newlen; |
| 94 | } |
| 95 | } |
| 96 | |
| 97 | /* Push VALUE onto CTX's stack. */ |
| 98 | |
| 99 | void |
| 100 | dwarf_expr_push (struct dwarf_expr_context *ctx, ULONGEST value, |
| 101 | int in_stack_memory) |
| 102 | { |
| 103 | struct dwarf_stack_value *v; |
| 104 | |
| 105 | /* We keep all stack elements within the range defined by the |
| 106 | DWARF address size. */ |
| 107 | if (ctx->addr_size < sizeof (ULONGEST)) |
| 108 | value &= ((ULONGEST) 1 << (ctx->addr_size * HOST_CHAR_BIT)) - 1; |
| 109 | |
| 110 | dwarf_expr_grow_stack (ctx, 1); |
| 111 | v = &ctx->stack[ctx->stack_len++]; |
| 112 | v->value = value; |
| 113 | v->in_stack_memory = in_stack_memory; |
| 114 | } |
| 115 | |
| 116 | /* Pop the top item off of CTX's stack. */ |
| 117 | |
| 118 | void |
| 119 | dwarf_expr_pop (struct dwarf_expr_context *ctx) |
| 120 | { |
| 121 | if (ctx->stack_len <= 0) |
| 122 | error (_("dwarf expression stack underflow")); |
| 123 | ctx->stack_len--; |
| 124 | } |
| 125 | |
| 126 | /* Retrieve the N'th item on CTX's stack. */ |
| 127 | |
| 128 | ULONGEST |
| 129 | dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n) |
| 130 | { |
| 131 | if (ctx->stack_len <= n) |
| 132 | error (_("Asked for position %d of stack, " |
| 133 | "stack only has %d elements on it."), |
| 134 | n, ctx->stack_len); |
| 135 | return ctx->stack[ctx->stack_len - (1 + n)].value; |
| 136 | |
| 137 | } |
| 138 | |
| 139 | /* Retrieve the N'th item on CTX's stack, converted to an address. */ |
| 140 | |
| 141 | CORE_ADDR |
| 142 | dwarf_expr_fetch_address (struct dwarf_expr_context *ctx, int n) |
| 143 | { |
| 144 | ULONGEST result = dwarf_expr_fetch (ctx, n); |
| 145 | |
| 146 | /* For most architectures, calling extract_unsigned_integer() alone |
| 147 | is sufficient for extracting an address. However, some |
| 148 | architectures (e.g. MIPS) use signed addresses and using |
| 149 | extract_unsigned_integer() will not produce a correct |
| 150 | result. Make sure we invoke gdbarch_integer_to_address() |
| 151 | for those architectures which require it. */ |
| 152 | if (gdbarch_integer_to_address_p (ctx->gdbarch)) |
| 153 | { |
| 154 | enum bfd_endian byte_order = gdbarch_byte_order (ctx->gdbarch); |
| 155 | gdb_byte *buf = alloca (ctx->addr_size); |
| 156 | struct type *int_type; |
| 157 | |
| 158 | switch (ctx->addr_size) |
| 159 | { |
| 160 | case 2: |
| 161 | int_type = builtin_type (ctx->gdbarch)->builtin_uint16; |
| 162 | break; |
| 163 | case 4: |
| 164 | int_type = builtin_type (ctx->gdbarch)->builtin_uint32; |
| 165 | break; |
| 166 | case 8: |
| 167 | int_type = builtin_type (ctx->gdbarch)->builtin_uint64; |
| 168 | break; |
| 169 | default: |
| 170 | internal_error (__FILE__, __LINE__, |
| 171 | _("Unsupported address size.\n")); |
| 172 | } |
| 173 | |
| 174 | store_unsigned_integer (buf, ctx->addr_size, byte_order, result); |
| 175 | return gdbarch_integer_to_address (ctx->gdbarch, int_type, buf); |
| 176 | } |
| 177 | |
| 178 | return (CORE_ADDR) result; |
| 179 | } |
| 180 | |
| 181 | /* Retrieve the in_stack_memory flag of the N'th item on CTX's stack. */ |
| 182 | |
| 183 | int |
| 184 | dwarf_expr_fetch_in_stack_memory (struct dwarf_expr_context *ctx, int n) |
| 185 | { |
| 186 | if (ctx->stack_len <= n) |
| 187 | error (_("Asked for position %d of stack, " |
| 188 | "stack only has %d elements on it."), |
| 189 | n, ctx->stack_len); |
| 190 | return ctx->stack[ctx->stack_len - (1 + n)].in_stack_memory; |
| 191 | |
| 192 | } |
| 193 | |
| 194 | /* Return true if the expression stack is empty. */ |
| 195 | |
| 196 | static int |
| 197 | dwarf_expr_stack_empty_p (struct dwarf_expr_context *ctx) |
| 198 | { |
| 199 | return ctx->stack_len == 0; |
| 200 | } |
| 201 | |
| 202 | /* Add a new piece to CTX's piece list. */ |
| 203 | static void |
| 204 | add_piece (struct dwarf_expr_context *ctx, ULONGEST size, ULONGEST offset) |
| 205 | { |
| 206 | struct dwarf_expr_piece *p; |
| 207 | |
| 208 | ctx->num_pieces++; |
| 209 | |
| 210 | ctx->pieces = xrealloc (ctx->pieces, |
| 211 | (ctx->num_pieces |
| 212 | * sizeof (struct dwarf_expr_piece))); |
| 213 | |
| 214 | p = &ctx->pieces[ctx->num_pieces - 1]; |
| 215 | p->location = ctx->location; |
| 216 | p->size = size; |
| 217 | p->offset = offset; |
| 218 | |
| 219 | if (p->location == DWARF_VALUE_LITERAL) |
| 220 | { |
| 221 | p->v.literal.data = ctx->data; |
| 222 | p->v.literal.length = ctx->len; |
| 223 | } |
| 224 | else if (dwarf_expr_stack_empty_p (ctx)) |
| 225 | { |
| 226 | p->location = DWARF_VALUE_OPTIMIZED_OUT; |
| 227 | /* Also reset the context's location, for our callers. This is |
| 228 | a somewhat strange approach, but this lets us avoid setting |
| 229 | the location to DWARF_VALUE_MEMORY in all the individual |
| 230 | cases in the evaluator. */ |
| 231 | ctx->location = DWARF_VALUE_OPTIMIZED_OUT; |
| 232 | } |
| 233 | else if (p->location == DWARF_VALUE_MEMORY) |
| 234 | { |
| 235 | p->v.mem.addr = dwarf_expr_fetch_address (ctx, 0); |
| 236 | p->v.mem.in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, 0); |
| 237 | } |
| 238 | else if (p->location == DWARF_VALUE_IMPLICIT_POINTER) |
| 239 | { |
| 240 | p->v.ptr.die = ctx->len; |
| 241 | p->v.ptr.offset = (LONGEST) dwarf_expr_fetch (ctx, 0); |
| 242 | } |
| 243 | else |
| 244 | { |
| 245 | p->v.value = dwarf_expr_fetch (ctx, 0); |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | /* Evaluate the expression at ADDR (LEN bytes long) using the context |
| 250 | CTX. */ |
| 251 | |
| 252 | void |
| 253 | dwarf_expr_eval (struct dwarf_expr_context *ctx, const gdb_byte *addr, |
| 254 | size_t len) |
| 255 | { |
| 256 | int old_recursion_depth = ctx->recursion_depth; |
| 257 | |
| 258 | execute_stack_op (ctx, addr, addr + len); |
| 259 | |
| 260 | /* CTX RECURSION_DEPTH becomes invalid if an exception was thrown here. */ |
| 261 | |
| 262 | gdb_assert (ctx->recursion_depth == old_recursion_depth); |
| 263 | } |
| 264 | |
| 265 | /* Decode the unsigned LEB128 constant at BUF into the variable pointed to |
| 266 | by R, and return the new value of BUF. Verify that it doesn't extend |
| 267 | past BUF_END. */ |
| 268 | |
| 269 | const gdb_byte * |
| 270 | read_uleb128 (const gdb_byte *buf, const gdb_byte *buf_end, ULONGEST * r) |
| 271 | { |
| 272 | unsigned shift = 0; |
| 273 | ULONGEST result = 0; |
| 274 | gdb_byte byte; |
| 275 | |
| 276 | while (1) |
| 277 | { |
| 278 | if (buf >= buf_end) |
| 279 | error (_("read_uleb128: Corrupted DWARF expression.")); |
| 280 | |
| 281 | byte = *buf++; |
| 282 | result |= (byte & 0x7f) << shift; |
| 283 | if ((byte & 0x80) == 0) |
| 284 | break; |
| 285 | shift += 7; |
| 286 | } |
| 287 | *r = result; |
| 288 | return buf; |
| 289 | } |
| 290 | |
| 291 | /* Decode the signed LEB128 constant at BUF into the variable pointed to |
| 292 | by R, and return the new value of BUF. Verify that it doesn't extend |
| 293 | past BUF_END. */ |
| 294 | |
| 295 | const gdb_byte * |
| 296 | read_sleb128 (const gdb_byte *buf, const gdb_byte *buf_end, LONGEST * r) |
| 297 | { |
| 298 | unsigned shift = 0; |
| 299 | LONGEST result = 0; |
| 300 | gdb_byte byte; |
| 301 | |
| 302 | while (1) |
| 303 | { |
| 304 | if (buf >= buf_end) |
| 305 | error (_("read_sleb128: Corrupted DWARF expression.")); |
| 306 | |
| 307 | byte = *buf++; |
| 308 | result |= (byte & 0x7f) << shift; |
| 309 | shift += 7; |
| 310 | if ((byte & 0x80) == 0) |
| 311 | break; |
| 312 | } |
| 313 | if (shift < (sizeof (*r) * 8) && (byte & 0x40) != 0) |
| 314 | result |= -(1 << shift); |
| 315 | |
| 316 | *r = result; |
| 317 | return buf; |
| 318 | } |
| 319 | \f |
| 320 | |
| 321 | /* Check that the current operator is either at the end of an |
| 322 | expression, or that it is followed by a composition operator. */ |
| 323 | |
| 324 | void |
| 325 | dwarf_expr_require_composition (const gdb_byte *op_ptr, const gdb_byte *op_end, |
| 326 | const char *op_name) |
| 327 | { |
| 328 | /* It seems like DW_OP_GNU_uninit should be handled here. However, |
| 329 | it doesn't seem to make sense for DW_OP_*_value, and it was not |
| 330 | checked at the other place that this function is called. */ |
| 331 | if (op_ptr != op_end && *op_ptr != DW_OP_piece && *op_ptr != DW_OP_bit_piece) |
| 332 | error (_("DWARF-2 expression error: `%s' operations must be " |
| 333 | "used either alone or in conjuction with DW_OP_piece " |
| 334 | "or DW_OP_bit_piece."), |
| 335 | op_name); |
| 336 | } |
| 337 | |
| 338 | /* The engine for the expression evaluator. Using the context in CTX, |
| 339 | evaluate the expression between OP_PTR and OP_END. */ |
| 340 | |
| 341 | static void |
| 342 | execute_stack_op (struct dwarf_expr_context *ctx, |
| 343 | const gdb_byte *op_ptr, const gdb_byte *op_end) |
| 344 | { |
| 345 | #define sign_ext(x) ((LONGEST) (((x) ^ sign_bit) - sign_bit)) |
| 346 | ULONGEST sign_bit = (ctx->addr_size >= sizeof (ULONGEST) ? 0 |
| 347 | : ((ULONGEST) 1) << (ctx->addr_size * 8 - 1)); |
| 348 | enum bfd_endian byte_order = gdbarch_byte_order (ctx->gdbarch); |
| 349 | |
| 350 | ctx->location = DWARF_VALUE_MEMORY; |
| 351 | ctx->initialized = 1; /* Default is initialized. */ |
| 352 | |
| 353 | if (ctx->recursion_depth > ctx->max_recursion_depth) |
| 354 | error (_("DWARF-2 expression error: Loop detected (%d)."), |
| 355 | ctx->recursion_depth); |
| 356 | ctx->recursion_depth++; |
| 357 | |
| 358 | while (op_ptr < op_end) |
| 359 | { |
| 360 | enum dwarf_location_atom op = *op_ptr++; |
| 361 | ULONGEST result; |
| 362 | /* Assume the value is not in stack memory. |
| 363 | Code that knows otherwise sets this to 1. |
| 364 | Some arithmetic on stack addresses can probably be assumed to still |
| 365 | be a stack address, but we skip this complication for now. |
| 366 | This is just an optimization, so it's always ok to punt |
| 367 | and leave this as 0. */ |
| 368 | int in_stack_memory = 0; |
| 369 | ULONGEST uoffset, reg; |
| 370 | LONGEST offset; |
| 371 | |
| 372 | switch (op) |
| 373 | { |
| 374 | case DW_OP_lit0: |
| 375 | case DW_OP_lit1: |
| 376 | case DW_OP_lit2: |
| 377 | case DW_OP_lit3: |
| 378 | case DW_OP_lit4: |
| 379 | case DW_OP_lit5: |
| 380 | case DW_OP_lit6: |
| 381 | case DW_OP_lit7: |
| 382 | case DW_OP_lit8: |
| 383 | case DW_OP_lit9: |
| 384 | case DW_OP_lit10: |
| 385 | case DW_OP_lit11: |
| 386 | case DW_OP_lit12: |
| 387 | case DW_OP_lit13: |
| 388 | case DW_OP_lit14: |
| 389 | case DW_OP_lit15: |
| 390 | case DW_OP_lit16: |
| 391 | case DW_OP_lit17: |
| 392 | case DW_OP_lit18: |
| 393 | case DW_OP_lit19: |
| 394 | case DW_OP_lit20: |
| 395 | case DW_OP_lit21: |
| 396 | case DW_OP_lit22: |
| 397 | case DW_OP_lit23: |
| 398 | case DW_OP_lit24: |
| 399 | case DW_OP_lit25: |
| 400 | case DW_OP_lit26: |
| 401 | case DW_OP_lit27: |
| 402 | case DW_OP_lit28: |
| 403 | case DW_OP_lit29: |
| 404 | case DW_OP_lit30: |
| 405 | case DW_OP_lit31: |
| 406 | result = op - DW_OP_lit0; |
| 407 | break; |
| 408 | |
| 409 | case DW_OP_addr: |
| 410 | result = extract_unsigned_integer (op_ptr, |
| 411 | ctx->addr_size, byte_order); |
| 412 | op_ptr += ctx->addr_size; |
| 413 | /* Some versions of GCC emit DW_OP_addr before |
| 414 | DW_OP_GNU_push_tls_address. In this case the value is an |
| 415 | index, not an address. We don't support things like |
| 416 | branching between the address and the TLS op. */ |
| 417 | if (op_ptr >= op_end || *op_ptr != DW_OP_GNU_push_tls_address) |
| 418 | result += ctx->offset; |
| 419 | break; |
| 420 | |
| 421 | case DW_OP_const1u: |
| 422 | result = extract_unsigned_integer (op_ptr, 1, byte_order); |
| 423 | op_ptr += 1; |
| 424 | break; |
| 425 | case DW_OP_const1s: |
| 426 | result = extract_signed_integer (op_ptr, 1, byte_order); |
| 427 | op_ptr += 1; |
| 428 | break; |
| 429 | case DW_OP_const2u: |
| 430 | result = extract_unsigned_integer (op_ptr, 2, byte_order); |
| 431 | op_ptr += 2; |
| 432 | break; |
| 433 | case DW_OP_const2s: |
| 434 | result = extract_signed_integer (op_ptr, 2, byte_order); |
| 435 | op_ptr += 2; |
| 436 | break; |
| 437 | case DW_OP_const4u: |
| 438 | result = extract_unsigned_integer (op_ptr, 4, byte_order); |
| 439 | op_ptr += 4; |
| 440 | break; |
| 441 | case DW_OP_const4s: |
| 442 | result = extract_signed_integer (op_ptr, 4, byte_order); |
| 443 | op_ptr += 4; |
| 444 | break; |
| 445 | case DW_OP_const8u: |
| 446 | result = extract_unsigned_integer (op_ptr, 8, byte_order); |
| 447 | op_ptr += 8; |
| 448 | break; |
| 449 | case DW_OP_const8s: |
| 450 | result = extract_signed_integer (op_ptr, 8, byte_order); |
| 451 | op_ptr += 8; |
| 452 | break; |
| 453 | case DW_OP_constu: |
| 454 | op_ptr = read_uleb128 (op_ptr, op_end, &uoffset); |
| 455 | result = uoffset; |
| 456 | break; |
| 457 | case DW_OP_consts: |
| 458 | op_ptr = read_sleb128 (op_ptr, op_end, &offset); |
| 459 | result = offset; |
| 460 | break; |
| 461 | |
| 462 | /* The DW_OP_reg operations are required to occur alone in |
| 463 | location expressions. */ |
| 464 | case DW_OP_reg0: |
| 465 | case DW_OP_reg1: |
| 466 | case DW_OP_reg2: |
| 467 | case DW_OP_reg3: |
| 468 | case DW_OP_reg4: |
| 469 | case DW_OP_reg5: |
| 470 | case DW_OP_reg6: |
| 471 | case DW_OP_reg7: |
| 472 | case DW_OP_reg8: |
| 473 | case DW_OP_reg9: |
| 474 | case DW_OP_reg10: |
| 475 | case DW_OP_reg11: |
| 476 | case DW_OP_reg12: |
| 477 | case DW_OP_reg13: |
| 478 | case DW_OP_reg14: |
| 479 | case DW_OP_reg15: |
| 480 | case DW_OP_reg16: |
| 481 | case DW_OP_reg17: |
| 482 | case DW_OP_reg18: |
| 483 | case DW_OP_reg19: |
| 484 | case DW_OP_reg20: |
| 485 | case DW_OP_reg21: |
| 486 | case DW_OP_reg22: |
| 487 | case DW_OP_reg23: |
| 488 | case DW_OP_reg24: |
| 489 | case DW_OP_reg25: |
| 490 | case DW_OP_reg26: |
| 491 | case DW_OP_reg27: |
| 492 | case DW_OP_reg28: |
| 493 | case DW_OP_reg29: |
| 494 | case DW_OP_reg30: |
| 495 | case DW_OP_reg31: |
| 496 | if (op_ptr != op_end |
| 497 | && *op_ptr != DW_OP_piece |
| 498 | && *op_ptr != DW_OP_bit_piece |
| 499 | && *op_ptr != DW_OP_GNU_uninit) |
| 500 | error (_("DWARF-2 expression error: DW_OP_reg operations must be " |
| 501 | "used either alone or in conjuction with DW_OP_piece " |
| 502 | "or DW_OP_bit_piece.")); |
| 503 | |
| 504 | result = op - DW_OP_reg0; |
| 505 | ctx->location = DWARF_VALUE_REGISTER; |
| 506 | break; |
| 507 | |
| 508 | case DW_OP_regx: |
| 509 | op_ptr = read_uleb128 (op_ptr, op_end, ®); |
| 510 | dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx"); |
| 511 | |
| 512 | result = reg; |
| 513 | ctx->location = DWARF_VALUE_REGISTER; |
| 514 | break; |
| 515 | |
| 516 | case DW_OP_implicit_value: |
| 517 | { |
| 518 | ULONGEST len; |
| 519 | |
| 520 | op_ptr = read_uleb128 (op_ptr, op_end, &len); |
| 521 | if (op_ptr + len > op_end) |
| 522 | error (_("DW_OP_implicit_value: too few bytes available.")); |
| 523 | ctx->len = len; |
| 524 | ctx->data = op_ptr; |
| 525 | ctx->location = DWARF_VALUE_LITERAL; |
| 526 | op_ptr += len; |
| 527 | dwarf_expr_require_composition (op_ptr, op_end, |
| 528 | "DW_OP_implicit_value"); |
| 529 | } |
| 530 | goto no_push; |
| 531 | |
| 532 | case DW_OP_stack_value: |
| 533 | ctx->location = DWARF_VALUE_STACK; |
| 534 | dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_stack_value"); |
| 535 | goto no_push; |
| 536 | |
| 537 | case DW_OP_GNU_implicit_pointer: |
| 538 | { |
| 539 | ULONGEST die; |
| 540 | LONGEST len; |
| 541 | |
| 542 | /* The referred-to DIE. */ |
| 543 | ctx->len = extract_unsigned_integer (op_ptr, ctx->addr_size, |
| 544 | byte_order); |
| 545 | op_ptr += ctx->addr_size; |
| 546 | |
| 547 | /* The byte offset into the data. */ |
| 548 | op_ptr = read_sleb128 (op_ptr, op_end, &len); |
| 549 | result = (ULONGEST) len; |
| 550 | |
| 551 | ctx->location = DWARF_VALUE_IMPLICIT_POINTER; |
| 552 | dwarf_expr_require_composition (op_ptr, op_end, |
| 553 | "DW_OP_GNU_implicit_pointer"); |
| 554 | } |
| 555 | break; |
| 556 | |
| 557 | case DW_OP_breg0: |
| 558 | case DW_OP_breg1: |
| 559 | case DW_OP_breg2: |
| 560 | case DW_OP_breg3: |
| 561 | case DW_OP_breg4: |
| 562 | case DW_OP_breg5: |
| 563 | case DW_OP_breg6: |
| 564 | case DW_OP_breg7: |
| 565 | case DW_OP_breg8: |
| 566 | case DW_OP_breg9: |
| 567 | case DW_OP_breg10: |
| 568 | case DW_OP_breg11: |
| 569 | case DW_OP_breg12: |
| 570 | case DW_OP_breg13: |
| 571 | case DW_OP_breg14: |
| 572 | case DW_OP_breg15: |
| 573 | case DW_OP_breg16: |
| 574 | case DW_OP_breg17: |
| 575 | case DW_OP_breg18: |
| 576 | case DW_OP_breg19: |
| 577 | case DW_OP_breg20: |
| 578 | case DW_OP_breg21: |
| 579 | case DW_OP_breg22: |
| 580 | case DW_OP_breg23: |
| 581 | case DW_OP_breg24: |
| 582 | case DW_OP_breg25: |
| 583 | case DW_OP_breg26: |
| 584 | case DW_OP_breg27: |
| 585 | case DW_OP_breg28: |
| 586 | case DW_OP_breg29: |
| 587 | case DW_OP_breg30: |
| 588 | case DW_OP_breg31: |
| 589 | { |
| 590 | op_ptr = read_sleb128 (op_ptr, op_end, &offset); |
| 591 | result = (ctx->read_reg) (ctx->baton, op - DW_OP_breg0); |
| 592 | result += offset; |
| 593 | } |
| 594 | break; |
| 595 | case DW_OP_bregx: |
| 596 | { |
| 597 | op_ptr = read_uleb128 (op_ptr, op_end, ®); |
| 598 | op_ptr = read_sleb128 (op_ptr, op_end, &offset); |
| 599 | result = (ctx->read_reg) (ctx->baton, reg); |
| 600 | result += offset; |
| 601 | } |
| 602 | break; |
| 603 | case DW_OP_fbreg: |
| 604 | { |
| 605 | const gdb_byte *datastart; |
| 606 | size_t datalen; |
| 607 | unsigned int before_stack_len; |
| 608 | |
| 609 | op_ptr = read_sleb128 (op_ptr, op_end, &offset); |
| 610 | /* Rather than create a whole new context, we simply |
| 611 | record the stack length before execution, then reset it |
| 612 | afterwards, effectively erasing whatever the recursive |
| 613 | call put there. */ |
| 614 | before_stack_len = ctx->stack_len; |
| 615 | /* FIXME: cagney/2003-03-26: This code should be using |
| 616 | get_frame_base_address(), and then implement a dwarf2 |
| 617 | specific this_base method. */ |
| 618 | (ctx->get_frame_base) (ctx->baton, &datastart, &datalen); |
| 619 | dwarf_expr_eval (ctx, datastart, datalen); |
| 620 | if (ctx->location == DWARF_VALUE_MEMORY) |
| 621 | result = dwarf_expr_fetch_address (ctx, 0); |
| 622 | else if (ctx->location == DWARF_VALUE_REGISTER) |
| 623 | result = (ctx->read_reg) (ctx->baton, dwarf_expr_fetch (ctx, 0)); |
| 624 | else |
| 625 | error (_("Not implemented: computing frame " |
| 626 | "base using explicit value operator")); |
| 627 | result = result + offset; |
| 628 | in_stack_memory = 1; |
| 629 | ctx->stack_len = before_stack_len; |
| 630 | ctx->location = DWARF_VALUE_MEMORY; |
| 631 | } |
| 632 | break; |
| 633 | |
| 634 | case DW_OP_dup: |
| 635 | result = dwarf_expr_fetch (ctx, 0); |
| 636 | in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, 0); |
| 637 | break; |
| 638 | |
| 639 | case DW_OP_drop: |
| 640 | dwarf_expr_pop (ctx); |
| 641 | goto no_push; |
| 642 | |
| 643 | case DW_OP_pick: |
| 644 | offset = *op_ptr++; |
| 645 | result = dwarf_expr_fetch (ctx, offset); |
| 646 | in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, offset); |
| 647 | break; |
| 648 | |
| 649 | case DW_OP_swap: |
| 650 | { |
| 651 | struct dwarf_stack_value t1, t2; |
| 652 | |
| 653 | if (ctx->stack_len < 2) |
| 654 | error (_("Not enough elements for " |
| 655 | "DW_OP_swap. Need 2, have %d."), |
| 656 | ctx->stack_len); |
| 657 | t1 = ctx->stack[ctx->stack_len - 1]; |
| 658 | t2 = ctx->stack[ctx->stack_len - 2]; |
| 659 | ctx->stack[ctx->stack_len - 1] = t2; |
| 660 | ctx->stack[ctx->stack_len - 2] = t1; |
| 661 | goto no_push; |
| 662 | } |
| 663 | |
| 664 | case DW_OP_over: |
| 665 | result = dwarf_expr_fetch (ctx, 1); |
| 666 | in_stack_memory = dwarf_expr_fetch_in_stack_memory (ctx, 1); |
| 667 | break; |
| 668 | |
| 669 | case DW_OP_rot: |
| 670 | { |
| 671 | struct dwarf_stack_value t1, t2, t3; |
| 672 | |
| 673 | if (ctx->stack_len < 3) |
| 674 | error (_("Not enough elements for " |
| 675 | "DW_OP_rot. Need 3, have %d."), |
| 676 | ctx->stack_len); |
| 677 | t1 = ctx->stack[ctx->stack_len - 1]; |
| 678 | t2 = ctx->stack[ctx->stack_len - 2]; |
| 679 | t3 = ctx->stack[ctx->stack_len - 3]; |
| 680 | ctx->stack[ctx->stack_len - 1] = t2; |
| 681 | ctx->stack[ctx->stack_len - 2] = t3; |
| 682 | ctx->stack[ctx->stack_len - 3] = t1; |
| 683 | goto no_push; |
| 684 | } |
| 685 | |
| 686 | case DW_OP_deref: |
| 687 | case DW_OP_deref_size: |
| 688 | { |
| 689 | int addr_size = (op == DW_OP_deref ? ctx->addr_size : *op_ptr++); |
| 690 | gdb_byte *buf = alloca (addr_size); |
| 691 | CORE_ADDR addr = dwarf_expr_fetch_address (ctx, 0); |
| 692 | dwarf_expr_pop (ctx); |
| 693 | |
| 694 | (ctx->read_mem) (ctx->baton, buf, addr, addr_size); |
| 695 | result = extract_unsigned_integer (buf, addr_size, byte_order); |
| 696 | break; |
| 697 | } |
| 698 | |
| 699 | case DW_OP_abs: |
| 700 | case DW_OP_neg: |
| 701 | case DW_OP_not: |
| 702 | case DW_OP_plus_uconst: |
| 703 | /* Unary operations. */ |
| 704 | result = dwarf_expr_fetch (ctx, 0); |
| 705 | dwarf_expr_pop (ctx); |
| 706 | |
| 707 | switch (op) |
| 708 | { |
| 709 | case DW_OP_abs: |
| 710 | if (sign_ext (result) < 0) |
| 711 | result = -result; |
| 712 | break; |
| 713 | case DW_OP_neg: |
| 714 | result = -result; |
| 715 | break; |
| 716 | case DW_OP_not: |
| 717 | result = ~result; |
| 718 | break; |
| 719 | case DW_OP_plus_uconst: |
| 720 | op_ptr = read_uleb128 (op_ptr, op_end, ®); |
| 721 | result += reg; |
| 722 | break; |
| 723 | } |
| 724 | break; |
| 725 | |
| 726 | case DW_OP_and: |
| 727 | case DW_OP_div: |
| 728 | case DW_OP_minus: |
| 729 | case DW_OP_mod: |
| 730 | case DW_OP_mul: |
| 731 | case DW_OP_or: |
| 732 | case DW_OP_plus: |
| 733 | case DW_OP_shl: |
| 734 | case DW_OP_shr: |
| 735 | case DW_OP_shra: |
| 736 | case DW_OP_xor: |
| 737 | case DW_OP_le: |
| 738 | case DW_OP_ge: |
| 739 | case DW_OP_eq: |
| 740 | case DW_OP_lt: |
| 741 | case DW_OP_gt: |
| 742 | case DW_OP_ne: |
| 743 | { |
| 744 | /* Binary operations. */ |
| 745 | ULONGEST first, second; |
| 746 | |
| 747 | second = dwarf_expr_fetch (ctx, 0); |
| 748 | dwarf_expr_pop (ctx); |
| 749 | |
| 750 | first = dwarf_expr_fetch (ctx, 0); |
| 751 | dwarf_expr_pop (ctx); |
| 752 | |
| 753 | switch (op) |
| 754 | { |
| 755 | case DW_OP_and: |
| 756 | result = first & second; |
| 757 | break; |
| 758 | case DW_OP_div: |
| 759 | if (!second) |
| 760 | error (_("Division by zero")); |
| 761 | result = sign_ext (first) / sign_ext (second); |
| 762 | break; |
| 763 | case DW_OP_minus: |
| 764 | result = first - second; |
| 765 | break; |
| 766 | case DW_OP_mod: |
| 767 | if (!second) |
| 768 | error (_("Division by zero")); |
| 769 | result = first % second; |
| 770 | break; |
| 771 | case DW_OP_mul: |
| 772 | result = first * second; |
| 773 | break; |
| 774 | case DW_OP_or: |
| 775 | result = first | second; |
| 776 | break; |
| 777 | case DW_OP_plus: |
| 778 | result = first + second; |
| 779 | break; |
| 780 | case DW_OP_shl: |
| 781 | result = first << second; |
| 782 | break; |
| 783 | case DW_OP_shr: |
| 784 | result = first >> second; |
| 785 | break; |
| 786 | case DW_OP_shra: |
| 787 | result = sign_ext (first) >> second; |
| 788 | break; |
| 789 | case DW_OP_xor: |
| 790 | result = first ^ second; |
| 791 | break; |
| 792 | case DW_OP_le: |
| 793 | result = sign_ext (first) <= sign_ext (second); |
| 794 | break; |
| 795 | case DW_OP_ge: |
| 796 | result = sign_ext (first) >= sign_ext (second); |
| 797 | break; |
| 798 | case DW_OP_eq: |
| 799 | result = sign_ext (first) == sign_ext (second); |
| 800 | break; |
| 801 | case DW_OP_lt: |
| 802 | result = sign_ext (first) < sign_ext (second); |
| 803 | break; |
| 804 | case DW_OP_gt: |
| 805 | result = sign_ext (first) > sign_ext (second); |
| 806 | break; |
| 807 | case DW_OP_ne: |
| 808 | result = sign_ext (first) != sign_ext (second); |
| 809 | break; |
| 810 | default: |
| 811 | internal_error (__FILE__, __LINE__, |
| 812 | _("Can't be reached.")); |
| 813 | } |
| 814 | } |
| 815 | break; |
| 816 | |
| 817 | case DW_OP_call_frame_cfa: |
| 818 | result = (ctx->get_frame_cfa) (ctx->baton); |
| 819 | in_stack_memory = 1; |
| 820 | break; |
| 821 | |
| 822 | case DW_OP_GNU_push_tls_address: |
| 823 | /* Variable is at a constant offset in the thread-local |
| 824 | storage block into the objfile for the current thread and |
| 825 | the dynamic linker module containing this expression. Here |
| 826 | we return returns the offset from that base. The top of the |
| 827 | stack has the offset from the beginning of the thread |
| 828 | control block at which the variable is located. Nothing |
| 829 | should follow this operator, so the top of stack would be |
| 830 | returned. */ |
| 831 | result = dwarf_expr_fetch (ctx, 0); |
| 832 | dwarf_expr_pop (ctx); |
| 833 | result = (ctx->get_tls_address) (ctx->baton, result); |
| 834 | break; |
| 835 | |
| 836 | case DW_OP_skip: |
| 837 | offset = extract_signed_integer (op_ptr, 2, byte_order); |
| 838 | op_ptr += 2; |
| 839 | op_ptr += offset; |
| 840 | goto no_push; |
| 841 | |
| 842 | case DW_OP_bra: |
| 843 | offset = extract_signed_integer (op_ptr, 2, byte_order); |
| 844 | op_ptr += 2; |
| 845 | if (dwarf_expr_fetch (ctx, 0) != 0) |
| 846 | op_ptr += offset; |
| 847 | dwarf_expr_pop (ctx); |
| 848 | goto no_push; |
| 849 | |
| 850 | case DW_OP_nop: |
| 851 | goto no_push; |
| 852 | |
| 853 | case DW_OP_piece: |
| 854 | { |
| 855 | ULONGEST size; |
| 856 | |
| 857 | /* Record the piece. */ |
| 858 | op_ptr = read_uleb128 (op_ptr, op_end, &size); |
| 859 | add_piece (ctx, 8 * size, 0); |
| 860 | |
| 861 | /* Pop off the address/regnum, and reset the location |
| 862 | type. */ |
| 863 | if (ctx->location != DWARF_VALUE_LITERAL |
| 864 | && ctx->location != DWARF_VALUE_OPTIMIZED_OUT) |
| 865 | dwarf_expr_pop (ctx); |
| 866 | ctx->location = DWARF_VALUE_MEMORY; |
| 867 | } |
| 868 | goto no_push; |
| 869 | |
| 870 | case DW_OP_bit_piece: |
| 871 | { |
| 872 | ULONGEST size, offset; |
| 873 | |
| 874 | /* Record the piece. */ |
| 875 | op_ptr = read_uleb128 (op_ptr, op_end, &size); |
| 876 | op_ptr = read_uleb128 (op_ptr, op_end, &offset); |
| 877 | add_piece (ctx, size, offset); |
| 878 | |
| 879 | /* Pop off the address/regnum, and reset the location |
| 880 | type. */ |
| 881 | if (ctx->location != DWARF_VALUE_LITERAL |
| 882 | && ctx->location != DWARF_VALUE_OPTIMIZED_OUT) |
| 883 | dwarf_expr_pop (ctx); |
| 884 | ctx->location = DWARF_VALUE_MEMORY; |
| 885 | } |
| 886 | goto no_push; |
| 887 | |
| 888 | case DW_OP_GNU_uninit: |
| 889 | if (op_ptr != op_end) |
| 890 | error (_("DWARF-2 expression error: DW_OP_GNU_uninit must always " |
| 891 | "be the very last op.")); |
| 892 | |
| 893 | ctx->initialized = 0; |
| 894 | goto no_push; |
| 895 | |
| 896 | case DW_OP_call2: |
| 897 | result = extract_unsigned_integer (op_ptr, 2, byte_order); |
| 898 | op_ptr += 2; |
| 899 | ctx->dwarf_call (ctx, result); |
| 900 | goto no_push; |
| 901 | |
| 902 | case DW_OP_call4: |
| 903 | result = extract_unsigned_integer (op_ptr, 4, byte_order); |
| 904 | op_ptr += 4; |
| 905 | ctx->dwarf_call (ctx, result); |
| 906 | goto no_push; |
| 907 | |
| 908 | default: |
| 909 | error (_("Unhandled dwarf expression opcode 0x%x"), op); |
| 910 | } |
| 911 | |
| 912 | /* Most things push a result value. */ |
| 913 | dwarf_expr_push (ctx, result, in_stack_memory); |
| 914 | no_push:; |
| 915 | } |
| 916 | |
| 917 | /* To simplify our main caller, if the result is an implicit |
| 918 | pointer, then make a pieced value. This is ok because we can't |
| 919 | have implicit pointers in contexts where pieces are invalid. */ |
| 920 | if (ctx->location == DWARF_VALUE_IMPLICIT_POINTER) |
| 921 | add_piece (ctx, 8 * ctx->addr_size, 0); |
| 922 | |
| 923 | ctx->recursion_depth--; |
| 924 | gdb_assert (ctx->recursion_depth >= 0); |
| 925 | #undef sign_ext |
| 926 | } |