1 /* Abstraction of GNU v3 abi. 2 Contributed by Jim Blandy <jimb@redhat.com> 3 4 Copyright (C) 2001-2016 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 3 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, see <http://www.gnu.org/licenses/>. */ 20 21 #include "defs.h" 22 #include "value.h" 23 #include "cp-abi.h" 24 #include "cp-support.h" 25 #include "demangle.h" 26 #include "objfiles.h" 27 #include "valprint.h" 28 #include "c-lang.h" 29 #include "typeprint.h" 30 31 static struct cp_abi_ops gnu_v3_abi_ops; 32 33 /* A gdbarch key for std::type_info, in the event that it can't be 34 found in the debug info. */ 35 36 static struct gdbarch_data *std_type_info_gdbarch_data; 37 38 39 static int 40 gnuv3_is_vtable_name (const char *name) 41 { 42 return startswith (name, "_ZTV"); 43 } 44 45 static int 46 gnuv3_is_operator_name (const char *name) 47 { 48 return startswith (name, "operator"); 49 } 50 51 52 /* To help us find the components of a vtable, we build ourselves a 53 GDB type object representing the vtable structure. Following the 54 V3 ABI, it goes something like this: 55 56 struct gdb_gnu_v3_abi_vtable { 57 58 / * An array of virtual call and virtual base offsets. The real 59 length of this array depends on the class hierarchy; we use 60 negative subscripts to access the elements. Yucky, but 61 better than the alternatives. * / 62 ptrdiff_t vcall_and_vbase_offsets[0]; 63 64 / * The offset from a virtual pointer referring to this table 65 to the top of the complete object. * / 66 ptrdiff_t offset_to_top; 67 68 / * The type_info pointer for this class. This is really a 69 std::type_info *, but GDB doesn't really look at the 70 type_info object itself, so we don't bother to get the type 71 exactly right. * / 72 void *type_info; 73 74 / * Virtual table pointers in objects point here. * / 75 76 / * Virtual function pointers. Like the vcall/vbase array, the 77 real length of this table depends on the class hierarchy. * / 78 void (*virtual_functions[0]) (); 79 80 }; 81 82 The catch, of course, is that the exact layout of this table 83 depends on the ABI --- word size, endianness, alignment, etc. So 84 the GDB type object is actually a per-architecture kind of thing. 85 86 vtable_type_gdbarch_data is a gdbarch per-architecture data pointer 87 which refers to the struct type * for this structure, laid out 88 appropriately for the architecture. */ 89 static struct gdbarch_data *vtable_type_gdbarch_data; 90 91 92 /* Human-readable names for the numbers of the fields above. */ 93 enum { 94 vtable_field_vcall_and_vbase_offsets, 95 vtable_field_offset_to_top, 96 vtable_field_type_info, 97 vtable_field_virtual_functions 98 }; 99 100 101 /* Return a GDB type representing `struct gdb_gnu_v3_abi_vtable', 102 described above, laid out appropriately for ARCH. 103 104 We use this function as the gdbarch per-architecture data 105 initialization function. */ 106 static void * 107 build_gdb_vtable_type (struct gdbarch *arch) 108 { 109 struct type *t; 110 struct field *field_list, *field; 111 int offset; 112 113 struct type *void_ptr_type 114 = builtin_type (arch)->builtin_data_ptr; 115 struct type *ptr_to_void_fn_type 116 = builtin_type (arch)->builtin_func_ptr; 117 118 /* ARCH can't give us the true ptrdiff_t type, so we guess. */ 119 struct type *ptrdiff_type 120 = arch_integer_type (arch, gdbarch_ptr_bit (arch), 0, "ptrdiff_t"); 121 122 /* We assume no padding is necessary, since GDB doesn't know 123 anything about alignment at the moment. If this assumption bites 124 us, we should add a gdbarch method which, given a type, returns 125 the alignment that type requires, and then use that here. */ 126 127 /* Build the field list. */ 128 field_list = XCNEWVEC (struct field, 4); 129 field = &field_list[0]; 130 offset = 0; 131 132 /* ptrdiff_t vcall_and_vbase_offsets[0]; */ 133 FIELD_NAME (*field) = "vcall_and_vbase_offsets"; 134 FIELD_TYPE (*field) = lookup_array_range_type (ptrdiff_type, 0, -1); 135 SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT); 136 offset += TYPE_LENGTH (FIELD_TYPE (*field)); 137 field++; 138 139 /* ptrdiff_t offset_to_top; */ 140 FIELD_NAME (*field) = "offset_to_top"; 141 FIELD_TYPE (*field) = ptrdiff_type; 142 SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT); 143 offset += TYPE_LENGTH (FIELD_TYPE (*field)); 144 field++; 145 146 /* void *type_info; */ 147 FIELD_NAME (*field) = "type_info"; 148 FIELD_TYPE (*field) = void_ptr_type; 149 SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT); 150 offset += TYPE_LENGTH (FIELD_TYPE (*field)); 151 field++; 152 153 /* void (*virtual_functions[0]) (); */ 154 FIELD_NAME (*field) = "virtual_functions"; 155 FIELD_TYPE (*field) = lookup_array_range_type (ptr_to_void_fn_type, 0, -1); 156 SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT); 157 offset += TYPE_LENGTH (FIELD_TYPE (*field)); 158 field++; 159 160 /* We assumed in the allocation above that there were four fields. */ 161 gdb_assert (field == (field_list + 4)); 162 163 t = arch_type (arch, TYPE_CODE_STRUCT, offset, NULL); 164 TYPE_NFIELDS (t) = field - field_list; 165 TYPE_FIELDS (t) = field_list; 166 TYPE_TAG_NAME (t) = "gdb_gnu_v3_abi_vtable"; 167 INIT_CPLUS_SPECIFIC (t); 168 169 return make_type_with_address_space (t, TYPE_INSTANCE_FLAG_CODE_SPACE); 170 } 171 172 173 /* Return the ptrdiff_t type used in the vtable type. */ 174 static struct type * 175 vtable_ptrdiff_type (struct gdbarch *gdbarch) 176 { 177 struct type *vtable_type 178 = (struct type *) gdbarch_data (gdbarch, vtable_type_gdbarch_data); 179 180 /* The "offset_to_top" field has the appropriate (ptrdiff_t) type. */ 181 return TYPE_FIELD_TYPE (vtable_type, vtable_field_offset_to_top); 182 } 183 184 /* Return the offset from the start of the imaginary `struct 185 gdb_gnu_v3_abi_vtable' object to the vtable's "address point" 186 (i.e., where objects' virtual table pointers point). */ 187 static int 188 vtable_address_point_offset (struct gdbarch *gdbarch) 189 { 190 struct type *vtable_type 191 = (struct type *) gdbarch_data (gdbarch, vtable_type_gdbarch_data); 192 193 return (TYPE_FIELD_BITPOS (vtable_type, vtable_field_virtual_functions) 194 / TARGET_CHAR_BIT); 195 } 196 197 198 /* Determine whether structure TYPE is a dynamic class. Cache the 199 result. */ 200 201 static int 202 gnuv3_dynamic_class (struct type *type) 203 { 204 int fieldnum, fieldelem; 205 206 type = check_typedef (type); 207 gdb_assert (TYPE_CODE (type) == TYPE_CODE_STRUCT 208 || TYPE_CODE (type) == TYPE_CODE_UNION); 209 210 if (TYPE_CODE (type) == TYPE_CODE_UNION) 211 return 0; 212 213 if (TYPE_CPLUS_DYNAMIC (type)) 214 return TYPE_CPLUS_DYNAMIC (type) == 1; 215 216 ALLOCATE_CPLUS_STRUCT_TYPE (type); 217 218 for (fieldnum = 0; fieldnum < TYPE_N_BASECLASSES (type); fieldnum++) 219 if (BASETYPE_VIA_VIRTUAL (type, fieldnum) 220 || gnuv3_dynamic_class (TYPE_FIELD_TYPE (type, fieldnum))) 221 { 222 TYPE_CPLUS_DYNAMIC (type) = 1; 223 return 1; 224 } 225 226 for (fieldnum = 0; fieldnum < TYPE_NFN_FIELDS (type); fieldnum++) 227 for (fieldelem = 0; fieldelem < TYPE_FN_FIELDLIST_LENGTH (type, fieldnum); 228 fieldelem++) 229 { 230 struct fn_field *f = TYPE_FN_FIELDLIST1 (type, fieldnum); 231 232 if (TYPE_FN_FIELD_VIRTUAL_P (f, fieldelem)) 233 { 234 TYPE_CPLUS_DYNAMIC (type) = 1; 235 return 1; 236 } 237 } 238 239 TYPE_CPLUS_DYNAMIC (type) = -1; 240 return 0; 241 } 242 243 /* Find the vtable for a value of CONTAINER_TYPE located at 244 CONTAINER_ADDR. Return a value of the correct vtable type for this 245 architecture, or NULL if CONTAINER does not have a vtable. */ 246 247 static struct value * 248 gnuv3_get_vtable (struct gdbarch *gdbarch, 249 struct type *container_type, CORE_ADDR container_addr) 250 { 251 struct type *vtable_type 252 = (struct type *) gdbarch_data (gdbarch, vtable_type_gdbarch_data); 253 struct type *vtable_pointer_type; 254 struct value *vtable_pointer; 255 CORE_ADDR vtable_address; 256 257 container_type = check_typedef (container_type); 258 gdb_assert (TYPE_CODE (container_type) == TYPE_CODE_STRUCT); 259 260 /* If this type does not have a virtual table, don't read the first 261 field. */ 262 if (!gnuv3_dynamic_class (container_type)) 263 return NULL; 264 265 /* We do not consult the debug information to find the virtual table. 266 The ABI specifies that it is always at offset zero in any class, 267 and debug information may not represent it. 268 269 We avoid using value_contents on principle, because the object might 270 be large. */ 271 272 /* Find the type "pointer to virtual table". */ 273 vtable_pointer_type = lookup_pointer_type (vtable_type); 274 275 /* Load it from the start of the class. */ 276 vtable_pointer = value_at (vtable_pointer_type, container_addr); 277 vtable_address = value_as_address (vtable_pointer); 278 279 /* Correct it to point at the start of the virtual table, rather 280 than the address point. */ 281 return value_at_lazy (vtable_type, 282 vtable_address 283 - vtable_address_point_offset (gdbarch)); 284 } 285 286 287 static struct type * 288 gnuv3_rtti_type (struct value *value, 289 int *full_p, LONGEST *top_p, int *using_enc_p) 290 { 291 struct gdbarch *gdbarch; 292 struct type *values_type = check_typedef (value_type (value)); 293 struct value *vtable; 294 struct minimal_symbol *vtable_symbol; 295 const char *vtable_symbol_name; 296 const char *class_name; 297 struct type *run_time_type; 298 LONGEST offset_to_top; 299 const char *atsign; 300 301 /* We only have RTTI for class objects. */ 302 if (TYPE_CODE (values_type) != TYPE_CODE_STRUCT) 303 return NULL; 304 305 /* Java doesn't have RTTI following the C++ ABI. */ 306 if (TYPE_CPLUS_REALLY_JAVA (values_type)) 307 return NULL; 308 309 /* Determine architecture. */ 310 gdbarch = get_type_arch (values_type); 311 312 if (using_enc_p) 313 *using_enc_p = 0; 314 315 vtable = gnuv3_get_vtable (gdbarch, values_type, 316 value_as_address (value_addr (value))); 317 if (vtable == NULL) 318 return NULL; 319 320 /* Find the linker symbol for this vtable. */ 321 vtable_symbol 322 = lookup_minimal_symbol_by_pc (value_address (vtable) 323 + value_embedded_offset (vtable)).minsym; 324 if (! vtable_symbol) 325 return NULL; 326 327 /* The symbol's demangled name should be something like "vtable for 328 CLASS", where CLASS is the name of the run-time type of VALUE. 329 If we didn't like this approach, we could instead look in the 330 type_info object itself to get the class name. But this way 331 should work just as well, and doesn't read target memory. */ 332 vtable_symbol_name = MSYMBOL_DEMANGLED_NAME (vtable_symbol); 333 if (vtable_symbol_name == NULL 334 || !startswith (vtable_symbol_name, "vtable for ")) 335 { 336 warning (_("can't find linker symbol for virtual table for `%s' value"), 337 TYPE_SAFE_NAME (values_type)); 338 if (vtable_symbol_name) 339 warning (_(" found `%s' instead"), vtable_symbol_name); 340 return NULL; 341 } 342 class_name = vtable_symbol_name + 11; 343 344 /* Strip off @plt and version suffixes. */ 345 atsign = strchr (class_name, '@'); 346 if (atsign != NULL) 347 { 348 char *copy; 349 350 copy = (char *) alloca (atsign - class_name + 1); 351 memcpy (copy, class_name, atsign - class_name); 352 copy[atsign - class_name] = '\0'; 353 class_name = copy; 354 } 355 356 /* Try to look up the class name as a type name. */ 357 /* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */ 358 run_time_type = cp_lookup_rtti_type (class_name, NULL); 359 if (run_time_type == NULL) 360 return NULL; 361 362 /* Get the offset from VALUE to the top of the complete object. 363 NOTE: this is the reverse of the meaning of *TOP_P. */ 364 offset_to_top 365 = value_as_long (value_field (vtable, vtable_field_offset_to_top)); 366 367 if (full_p) 368 *full_p = (- offset_to_top == value_embedded_offset (value) 369 && (TYPE_LENGTH (value_enclosing_type (value)) 370 >= TYPE_LENGTH (run_time_type))); 371 if (top_p) 372 *top_p = - offset_to_top; 373 return run_time_type; 374 } 375 376 /* Return a function pointer for CONTAINER's VTABLE_INDEX'th virtual 377 function, of type FNTYPE. */ 378 379 static struct value * 380 gnuv3_get_virtual_fn (struct gdbarch *gdbarch, struct value *container, 381 struct type *fntype, int vtable_index) 382 { 383 struct value *vtable, *vfn; 384 385 /* Every class with virtual functions must have a vtable. */ 386 vtable = gnuv3_get_vtable (gdbarch, value_type (container), 387 value_as_address (value_addr (container))); 388 gdb_assert (vtable != NULL); 389 390 /* Fetch the appropriate function pointer from the vtable. */ 391 vfn = value_subscript (value_field (vtable, vtable_field_virtual_functions), 392 vtable_index); 393 394 /* If this architecture uses function descriptors directly in the vtable, 395 then the address of the vtable entry is actually a "function pointer" 396 (i.e. points to the descriptor). We don't need to scale the index 397 by the size of a function descriptor; GCC does that before outputing 398 debug information. */ 399 if (gdbarch_vtable_function_descriptors (gdbarch)) 400 vfn = value_addr (vfn); 401 402 /* Cast the function pointer to the appropriate type. */ 403 vfn = value_cast (lookup_pointer_type (fntype), vfn); 404 405 return vfn; 406 } 407 408 /* GNU v3 implementation of value_virtual_fn_field. See cp-abi.h 409 for a description of the arguments. */ 410 411 static struct value * 412 gnuv3_virtual_fn_field (struct value **value_p, 413 struct fn_field *f, int j, 414 struct type *vfn_base, int offset) 415 { 416 struct type *values_type = check_typedef (value_type (*value_p)); 417 struct gdbarch *gdbarch; 418 419 /* Some simple sanity checks. */ 420 if (TYPE_CODE (values_type) != TYPE_CODE_STRUCT) 421 error (_("Only classes can have virtual functions.")); 422 423 /* Determine architecture. */ 424 gdbarch = get_type_arch (values_type); 425 426 /* Cast our value to the base class which defines this virtual 427 function. This takes care of any necessary `this' 428 adjustments. */ 429 if (vfn_base != values_type) 430 *value_p = value_cast (vfn_base, *value_p); 431 432 return gnuv3_get_virtual_fn (gdbarch, *value_p, TYPE_FN_FIELD_TYPE (f, j), 433 TYPE_FN_FIELD_VOFFSET (f, j)); 434 } 435 436 /* Compute the offset of the baseclass which is 437 the INDEXth baseclass of class TYPE, 438 for value at VALADDR (in host) at ADDRESS (in target). 439 The result is the offset of the baseclass value relative 440 to (the address of)(ARG) + OFFSET. 441 442 -1 is returned on error. */ 443 444 static int 445 gnuv3_baseclass_offset (struct type *type, int index, 446 const bfd_byte *valaddr, LONGEST embedded_offset, 447 CORE_ADDR address, const struct value *val) 448 { 449 struct gdbarch *gdbarch; 450 struct type *ptr_type; 451 struct value *vtable; 452 struct value *vbase_array; 453 long int cur_base_offset, base_offset; 454 455 /* Determine architecture. */ 456 gdbarch = get_type_arch (type); 457 ptr_type = builtin_type (gdbarch)->builtin_data_ptr; 458 459 /* If it isn't a virtual base, this is easy. The offset is in the 460 type definition. Likewise for Java, which doesn't really have 461 virtual inheritance in the C++ sense. */ 462 if (!BASETYPE_VIA_VIRTUAL (type, index) || TYPE_CPLUS_REALLY_JAVA (type)) 463 return TYPE_BASECLASS_BITPOS (type, index) / 8; 464 465 /* To access a virtual base, we need to use the vbase offset stored in 466 our vtable. Recent GCC versions provide this information. If it isn't 467 available, we could get what we needed from RTTI, or from drawing the 468 complete inheritance graph based on the debug info. Neither is 469 worthwhile. */ 470 cur_base_offset = TYPE_BASECLASS_BITPOS (type, index) / 8; 471 if (cur_base_offset >= - vtable_address_point_offset (gdbarch)) 472 error (_("Expected a negative vbase offset (old compiler?)")); 473 474 cur_base_offset = cur_base_offset + vtable_address_point_offset (gdbarch); 475 if ((- cur_base_offset) % TYPE_LENGTH (ptr_type) != 0) 476 error (_("Misaligned vbase offset.")); 477 cur_base_offset = cur_base_offset / ((int) TYPE_LENGTH (ptr_type)); 478 479 vtable = gnuv3_get_vtable (gdbarch, type, address + embedded_offset); 480 gdb_assert (vtable != NULL); 481 vbase_array = value_field (vtable, vtable_field_vcall_and_vbase_offsets); 482 base_offset = value_as_long (value_subscript (vbase_array, cur_base_offset)); 483 return base_offset; 484 } 485 486 /* Locate a virtual method in DOMAIN or its non-virtual base classes 487 which has virtual table index VOFFSET. The method has an associated 488 "this" adjustment of ADJUSTMENT bytes. */ 489 490 static const char * 491 gnuv3_find_method_in (struct type *domain, CORE_ADDR voffset, 492 LONGEST adjustment) 493 { 494 int i; 495 496 /* Search this class first. */ 497 if (adjustment == 0) 498 { 499 int len; 500 501 len = TYPE_NFN_FIELDS (domain); 502 for (i = 0; i < len; i++) 503 { 504 int len2, j; 505 struct fn_field *f; 506 507 f = TYPE_FN_FIELDLIST1 (domain, i); 508 len2 = TYPE_FN_FIELDLIST_LENGTH (domain, i); 509 510 check_stub_method_group (domain, i); 511 for (j = 0; j < len2; j++) 512 if (TYPE_FN_FIELD_VOFFSET (f, j) == voffset) 513 return TYPE_FN_FIELD_PHYSNAME (f, j); 514 } 515 } 516 517 /* Next search non-virtual bases. If it's in a virtual base, 518 we're out of luck. */ 519 for (i = 0; i < TYPE_N_BASECLASSES (domain); i++) 520 { 521 int pos; 522 struct type *basetype; 523 524 if (BASETYPE_VIA_VIRTUAL (domain, i)) 525 continue; 526 527 pos = TYPE_BASECLASS_BITPOS (domain, i) / 8; 528 basetype = TYPE_FIELD_TYPE (domain, i); 529 /* Recurse with a modified adjustment. We don't need to adjust 530 voffset. */ 531 if (adjustment >= pos && adjustment < pos + TYPE_LENGTH (basetype)) 532 return gnuv3_find_method_in (basetype, voffset, adjustment - pos); 533 } 534 535 return NULL; 536 } 537 538 /* Decode GNU v3 method pointer. */ 539 540 static int 541 gnuv3_decode_method_ptr (struct gdbarch *gdbarch, 542 const gdb_byte *contents, 543 CORE_ADDR *value_p, 544 LONGEST *adjustment_p) 545 { 546 struct type *funcptr_type = builtin_type (gdbarch)->builtin_func_ptr; 547 struct type *offset_type = vtable_ptrdiff_type (gdbarch); 548 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 549 CORE_ADDR ptr_value; 550 LONGEST voffset, adjustment; 551 int vbit; 552 553 /* Extract the pointer to member. The first element is either a pointer 554 or a vtable offset. For pointers, we need to use extract_typed_address 555 to allow the back-end to convert the pointer to a GDB address -- but 556 vtable offsets we must handle as integers. At this point, we do not 557 yet know which case we have, so we extract the value under both 558 interpretations and choose the right one later on. */ 559 ptr_value = extract_typed_address (contents, funcptr_type); 560 voffset = extract_signed_integer (contents, 561 TYPE_LENGTH (funcptr_type), byte_order); 562 contents += TYPE_LENGTH (funcptr_type); 563 adjustment = extract_signed_integer (contents, 564 TYPE_LENGTH (offset_type), byte_order); 565 566 if (!gdbarch_vbit_in_delta (gdbarch)) 567 { 568 vbit = voffset & 1; 569 voffset = voffset ^ vbit; 570 } 571 else 572 { 573 vbit = adjustment & 1; 574 adjustment = adjustment >> 1; 575 } 576 577 *value_p = vbit? voffset : ptr_value; 578 *adjustment_p = adjustment; 579 return vbit; 580 } 581 582 /* GNU v3 implementation of cplus_print_method_ptr. */ 583 584 static void 585 gnuv3_print_method_ptr (const gdb_byte *contents, 586 struct type *type, 587 struct ui_file *stream) 588 { 589 struct type *self_type = TYPE_SELF_TYPE (type); 590 struct gdbarch *gdbarch = get_type_arch (self_type); 591 CORE_ADDR ptr_value; 592 LONGEST adjustment; 593 int vbit; 594 595 /* Extract the pointer to member. */ 596 vbit = gnuv3_decode_method_ptr (gdbarch, contents, &ptr_value, &adjustment); 597 598 /* Check for NULL. */ 599 if (ptr_value == 0 && vbit == 0) 600 { 601 fprintf_filtered (stream, "NULL"); 602 return; 603 } 604 605 /* Search for a virtual method. */ 606 if (vbit) 607 { 608 CORE_ADDR voffset; 609 const char *physname; 610 611 /* It's a virtual table offset, maybe in this class. Search 612 for a field with the correct vtable offset. First convert it 613 to an index, as used in TYPE_FN_FIELD_VOFFSET. */ 614 voffset = ptr_value / TYPE_LENGTH (vtable_ptrdiff_type (gdbarch)); 615 616 physname = gnuv3_find_method_in (self_type, voffset, adjustment); 617 618 /* If we found a method, print that. We don't bother to disambiguate 619 possible paths to the method based on the adjustment. */ 620 if (physname) 621 { 622 char *demangled_name = gdb_demangle (physname, 623 DMGL_ANSI | DMGL_PARAMS); 624 625 fprintf_filtered (stream, "&virtual "); 626 if (demangled_name == NULL) 627 fputs_filtered (physname, stream); 628 else 629 { 630 fputs_filtered (demangled_name, stream); 631 xfree (demangled_name); 632 } 633 return; 634 } 635 } 636 else if (ptr_value != 0) 637 { 638 /* Found a non-virtual function: print out the type. */ 639 fputs_filtered ("(", stream); 640 c_print_type (type, "", stream, -1, 0, &type_print_raw_options); 641 fputs_filtered (") ", stream); 642 } 643 644 /* We didn't find it; print the raw data. */ 645 if (vbit) 646 { 647 fprintf_filtered (stream, "&virtual table offset "); 648 print_longest (stream, 'd', 1, ptr_value); 649 } 650 else 651 { 652 struct value_print_options opts; 653 654 get_user_print_options (&opts); 655 print_address_demangle (&opts, gdbarch, ptr_value, stream, demangle); 656 } 657 658 if (adjustment) 659 { 660 fprintf_filtered (stream, ", this adjustment "); 661 print_longest (stream, 'd', 1, adjustment); 662 } 663 } 664 665 /* GNU v3 implementation of cplus_method_ptr_size. */ 666 667 static int 668 gnuv3_method_ptr_size (struct type *type) 669 { 670 struct gdbarch *gdbarch = get_type_arch (type); 671 672 return 2 * TYPE_LENGTH (builtin_type (gdbarch)->builtin_data_ptr); 673 } 674 675 /* GNU v3 implementation of cplus_make_method_ptr. */ 676 677 static void 678 gnuv3_make_method_ptr (struct type *type, gdb_byte *contents, 679 CORE_ADDR value, int is_virtual) 680 { 681 struct gdbarch *gdbarch = get_type_arch (type); 682 int size = TYPE_LENGTH (builtin_type (gdbarch)->builtin_data_ptr); 683 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 684 685 /* FIXME drow/2006-12-24: The adjustment of "this" is currently 686 always zero, since the method pointer is of the correct type. 687 But if the method pointer came from a base class, this is 688 incorrect - it should be the offset to the base. The best 689 fix might be to create the pointer to member pointing at the 690 base class and cast it to the derived class, but that requires 691 support for adjusting pointers to members when casting them - 692 not currently supported by GDB. */ 693 694 if (!gdbarch_vbit_in_delta (gdbarch)) 695 { 696 store_unsigned_integer (contents, size, byte_order, value | is_virtual); 697 store_unsigned_integer (contents + size, size, byte_order, 0); 698 } 699 else 700 { 701 store_unsigned_integer (contents, size, byte_order, value); 702 store_unsigned_integer (contents + size, size, byte_order, is_virtual); 703 } 704 } 705 706 /* GNU v3 implementation of cplus_method_ptr_to_value. */ 707 708 static struct value * 709 gnuv3_method_ptr_to_value (struct value **this_p, struct value *method_ptr) 710 { 711 struct gdbarch *gdbarch; 712 const gdb_byte *contents = value_contents (method_ptr); 713 CORE_ADDR ptr_value; 714 struct type *self_type, *final_type, *method_type; 715 LONGEST adjustment; 716 int vbit; 717 718 self_type = TYPE_SELF_TYPE (check_typedef (value_type (method_ptr))); 719 final_type = lookup_pointer_type (self_type); 720 721 method_type = TYPE_TARGET_TYPE (check_typedef (value_type (method_ptr))); 722 723 /* Extract the pointer to member. */ 724 gdbarch = get_type_arch (self_type); 725 vbit = gnuv3_decode_method_ptr (gdbarch, contents, &ptr_value, &adjustment); 726 727 /* First convert THIS to match the containing type of the pointer to 728 member. This cast may adjust the value of THIS. */ 729 *this_p = value_cast (final_type, *this_p); 730 731 /* Then apply whatever adjustment is necessary. This creates a somewhat 732 strange pointer: it claims to have type FINAL_TYPE, but in fact it 733 might not be a valid FINAL_TYPE. For instance, it might be a 734 base class of FINAL_TYPE. And if it's not the primary base class, 735 then printing it out as a FINAL_TYPE object would produce some pretty 736 garbage. 737 738 But we don't really know the type of the first argument in 739 METHOD_TYPE either, which is why this happens. We can't 740 dereference this later as a FINAL_TYPE, but once we arrive in the 741 called method we'll have debugging information for the type of 742 "this" - and that'll match the value we produce here. 743 744 You can provoke this case by casting a Base::* to a Derived::*, for 745 instance. */ 746 *this_p = value_cast (builtin_type (gdbarch)->builtin_data_ptr, *this_p); 747 *this_p = value_ptradd (*this_p, adjustment); 748 *this_p = value_cast (final_type, *this_p); 749 750 if (vbit) 751 { 752 LONGEST voffset; 753 754 voffset = ptr_value / TYPE_LENGTH (vtable_ptrdiff_type (gdbarch)); 755 return gnuv3_get_virtual_fn (gdbarch, value_ind (*this_p), 756 method_type, voffset); 757 } 758 else 759 return value_from_pointer (lookup_pointer_type (method_type), ptr_value); 760 } 761 762 /* Objects of this type are stored in a hash table and a vector when 763 printing the vtables for a class. */ 764 765 struct value_and_voffset 766 { 767 /* The value representing the object. */ 768 struct value *value; 769 770 /* The maximum vtable offset we've found for any object at this 771 offset in the outermost object. */ 772 int max_voffset; 773 }; 774 775 typedef struct value_and_voffset *value_and_voffset_p; 776 DEF_VEC_P (value_and_voffset_p); 777 778 /* Hash function for value_and_voffset. */ 779 780 static hashval_t 781 hash_value_and_voffset (const void *p) 782 { 783 const struct value_and_voffset *o = (const struct value_and_voffset *) p; 784 785 return value_address (o->value) + value_embedded_offset (o->value); 786 } 787 788 /* Equality function for value_and_voffset. */ 789 790 static int 791 eq_value_and_voffset (const void *a, const void *b) 792 { 793 const struct value_and_voffset *ova = (const struct value_and_voffset *) a; 794 const struct value_and_voffset *ovb = (const struct value_and_voffset *) b; 795 796 return (value_address (ova->value) + value_embedded_offset (ova->value) 797 == value_address (ovb->value) + value_embedded_offset (ovb->value)); 798 } 799 800 /* qsort comparison function for value_and_voffset. */ 801 802 static int 803 compare_value_and_voffset (const void *a, const void *b) 804 { 805 const struct value_and_voffset * const *ova 806 = (const struct value_and_voffset * const *) a; 807 CORE_ADDR addra = (value_address ((*ova)->value) 808 + value_embedded_offset ((*ova)->value)); 809 const struct value_and_voffset * const *ovb 810 = (const struct value_and_voffset * const *) b; 811 CORE_ADDR addrb = (value_address ((*ovb)->value) 812 + value_embedded_offset ((*ovb)->value)); 813 814 if (addra < addrb) 815 return -1; 816 if (addra > addrb) 817 return 1; 818 return 0; 819 } 820 821 /* A helper function used when printing vtables. This determines the 822 key (most derived) sub-object at each address and also computes the 823 maximum vtable offset seen for the corresponding vtable. Updates 824 OFFSET_HASH and OFFSET_VEC with a new value_and_voffset object, if 825 needed. VALUE is the object to examine. */ 826 827 static void 828 compute_vtable_size (htab_t offset_hash, 829 VEC (value_and_voffset_p) **offset_vec, 830 struct value *value) 831 { 832 int i; 833 struct type *type = check_typedef (value_type (value)); 834 void **slot; 835 struct value_and_voffset search_vo, *current_vo; 836 837 gdb_assert (TYPE_CODE (type) == TYPE_CODE_STRUCT); 838 839 /* If the object is not dynamic, then we are done; as it cannot have 840 dynamic base types either. */ 841 if (!gnuv3_dynamic_class (type)) 842 return; 843 844 /* Update the hash and the vec, if needed. */ 845 search_vo.value = value; 846 slot = htab_find_slot (offset_hash, &search_vo, INSERT); 847 if (*slot) 848 current_vo = (struct value_and_voffset *) *slot; 849 else 850 { 851 current_vo = XNEW (struct value_and_voffset); 852 current_vo->value = value; 853 current_vo->max_voffset = -1; 854 *slot = current_vo; 855 VEC_safe_push (value_and_voffset_p, *offset_vec, current_vo); 856 } 857 858 /* Update the value_and_voffset object with the highest vtable 859 offset from this class. */ 860 for (i = 0; i < TYPE_NFN_FIELDS (type); ++i) 861 { 862 int j; 863 struct fn_field *fn = TYPE_FN_FIELDLIST1 (type, i); 864 865 for (j = 0; j < TYPE_FN_FIELDLIST_LENGTH (type, i); ++j) 866 { 867 if (TYPE_FN_FIELD_VIRTUAL_P (fn, j)) 868 { 869 int voffset = TYPE_FN_FIELD_VOFFSET (fn, j); 870 871 if (voffset > current_vo->max_voffset) 872 current_vo->max_voffset = voffset; 873 } 874 } 875 } 876 877 /* Recurse into base classes. */ 878 for (i = 0; i < TYPE_N_BASECLASSES (type); ++i) 879 compute_vtable_size (offset_hash, offset_vec, value_field (value, i)); 880 } 881 882 /* Helper for gnuv3_print_vtable that prints a single vtable. */ 883 884 static void 885 print_one_vtable (struct gdbarch *gdbarch, struct value *value, 886 int max_voffset, 887 struct value_print_options *opts) 888 { 889 int i; 890 struct type *type = check_typedef (value_type (value)); 891 struct value *vtable; 892 CORE_ADDR vt_addr; 893 894 vtable = gnuv3_get_vtable (gdbarch, type, 895 value_address (value) 896 + value_embedded_offset (value)); 897 vt_addr = value_address (value_field (vtable, 898 vtable_field_virtual_functions)); 899 900 printf_filtered (_("vtable for '%s' @ %s (subobject @ %s):\n"), 901 TYPE_SAFE_NAME (type), 902 paddress (gdbarch, vt_addr), 903 paddress (gdbarch, (value_address (value) 904 + value_embedded_offset (value)))); 905 906 for (i = 0; i <= max_voffset; ++i) 907 { 908 /* Initialize it just to avoid a GCC false warning. */ 909 CORE_ADDR addr = 0; 910 int got_error = 0; 911 struct value *vfn; 912 913 printf_filtered ("[%d]: ", i); 914 915 vfn = value_subscript (value_field (vtable, 916 vtable_field_virtual_functions), 917 i); 918 919 if (gdbarch_vtable_function_descriptors (gdbarch)) 920 vfn = value_addr (vfn); 921 922 TRY 923 { 924 addr = value_as_address (vfn); 925 } 926 CATCH (ex, RETURN_MASK_ERROR) 927 { 928 printf_filtered (_("<error: %s>"), ex.message); 929 got_error = 1; 930 } 931 END_CATCH 932 933 if (!got_error) 934 print_function_pointer_address (opts, gdbarch, addr, gdb_stdout); 935 printf_filtered ("\n"); 936 } 937 } 938 939 /* Implementation of the print_vtable method. */ 940 941 static void 942 gnuv3_print_vtable (struct value *value) 943 { 944 struct gdbarch *gdbarch; 945 struct type *type; 946 struct value *vtable; 947 struct value_print_options opts; 948 htab_t offset_hash; 949 struct cleanup *cleanup; 950 VEC (value_and_voffset_p) *result_vec = NULL; 951 struct value_and_voffset *iter; 952 int i, count; 953 954 value = coerce_ref (value); 955 type = check_typedef (value_type (value)); 956 if (TYPE_CODE (type) == TYPE_CODE_PTR) 957 { 958 value = value_ind (value); 959 type = check_typedef (value_type (value)); 960 } 961 962 get_user_print_options (&opts); 963 964 /* Respect 'set print object'. */ 965 if (opts.objectprint) 966 { 967 value = value_full_object (value, NULL, 0, 0, 0); 968 type = check_typedef (value_type (value)); 969 } 970 971 gdbarch = get_type_arch (type); 972 973 vtable = NULL; 974 if (TYPE_CODE (type) == TYPE_CODE_STRUCT) 975 vtable = gnuv3_get_vtable (gdbarch, type, 976 value_as_address (value_addr (value))); 977 978 if (!vtable) 979 { 980 printf_filtered (_("This object does not have a virtual function table\n")); 981 return; 982 } 983 984 offset_hash = htab_create_alloc (1, hash_value_and_voffset, 985 eq_value_and_voffset, 986 xfree, xcalloc, xfree); 987 cleanup = make_cleanup_htab_delete (offset_hash); 988 make_cleanup (VEC_cleanup (value_and_voffset_p), &result_vec); 989 990 compute_vtable_size (offset_hash, &result_vec, value); 991 992 qsort (VEC_address (value_and_voffset_p, result_vec), 993 VEC_length (value_and_voffset_p, result_vec), 994 sizeof (value_and_voffset_p), 995 compare_value_and_voffset); 996 997 count = 0; 998 for (i = 0; VEC_iterate (value_and_voffset_p, result_vec, i, iter); ++i) 999 { 1000 if (iter->max_voffset >= 0) 1001 { 1002 if (count > 0) 1003 printf_filtered ("\n"); 1004 print_one_vtable (gdbarch, iter->value, iter->max_voffset, &opts); 1005 ++count; 1006 } 1007 } 1008 1009 do_cleanups (cleanup); 1010 } 1011 1012 /* Return a GDB type representing `struct std::type_info', laid out 1013 appropriately for ARCH. 1014 1015 We use this function as the gdbarch per-architecture data 1016 initialization function. */ 1017 1018 static void * 1019 build_std_type_info_type (struct gdbarch *arch) 1020 { 1021 struct type *t; 1022 struct field *field_list, *field; 1023 int offset; 1024 struct type *void_ptr_type 1025 = builtin_type (arch)->builtin_data_ptr; 1026 struct type *char_type 1027 = builtin_type (arch)->builtin_char; 1028 struct type *char_ptr_type 1029 = make_pointer_type (make_cv_type (1, 0, char_type, NULL), NULL); 1030 1031 field_list = XCNEWVEC (struct field, 2); 1032 field = &field_list[0]; 1033 offset = 0; 1034 1035 /* The vtable. */ 1036 FIELD_NAME (*field) = "_vptr.type_info"; 1037 FIELD_TYPE (*field) = void_ptr_type; 1038 SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT); 1039 offset += TYPE_LENGTH (FIELD_TYPE (*field)); 1040 field++; 1041 1042 /* The name. */ 1043 FIELD_NAME (*field) = "__name"; 1044 FIELD_TYPE (*field) = char_ptr_type; 1045 SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT); 1046 offset += TYPE_LENGTH (FIELD_TYPE (*field)); 1047 field++; 1048 1049 gdb_assert (field == (field_list + 2)); 1050 1051 t = arch_type (arch, TYPE_CODE_STRUCT, offset, NULL); 1052 TYPE_NFIELDS (t) = field - field_list; 1053 TYPE_FIELDS (t) = field_list; 1054 TYPE_TAG_NAME (t) = "gdb_gnu_v3_type_info"; 1055 INIT_CPLUS_SPECIFIC (t); 1056 1057 return t; 1058 } 1059 1060 /* Implement the 'get_typeid_type' method. */ 1061 1062 static struct type * 1063 gnuv3_get_typeid_type (struct gdbarch *gdbarch) 1064 { 1065 struct symbol *typeinfo; 1066 struct type *typeinfo_type; 1067 1068 typeinfo = lookup_symbol ("std::type_info", NULL, STRUCT_DOMAIN, 1069 NULL).symbol; 1070 if (typeinfo == NULL) 1071 typeinfo_type 1072 = (struct type *) gdbarch_data (gdbarch, std_type_info_gdbarch_data); 1073 else 1074 typeinfo_type = SYMBOL_TYPE (typeinfo); 1075 1076 return typeinfo_type; 1077 } 1078 1079 /* Implement the 'get_typeid' method. */ 1080 1081 static struct value * 1082 gnuv3_get_typeid (struct value *value) 1083 { 1084 struct type *typeinfo_type; 1085 struct type *type; 1086 struct gdbarch *gdbarch; 1087 struct cleanup *cleanup; 1088 struct value *result; 1089 char *type_name, *canonical; 1090 1091 /* We have to handle values a bit trickily here, to allow this code 1092 to work properly with non_lvalue values that are really just 1093 disguised types. */ 1094 if (value_lval_const (value) == lval_memory) 1095 value = coerce_ref (value); 1096 1097 type = check_typedef (value_type (value)); 1098 1099 /* In the non_lvalue case, a reference might have slipped through 1100 here. */ 1101 if (TYPE_CODE (type) == TYPE_CODE_REF) 1102 type = check_typedef (TYPE_TARGET_TYPE (type)); 1103 1104 /* Ignore top-level cv-qualifiers. */ 1105 type = make_cv_type (0, 0, type, NULL); 1106 gdbarch = get_type_arch (type); 1107 1108 type_name = type_to_string (type); 1109 if (type_name == NULL) 1110 error (_("cannot find typeinfo for unnamed type")); 1111 cleanup = make_cleanup (xfree, type_name); 1112 1113 /* We need to canonicalize the type name here, because we do lookups 1114 using the demangled name, and so we must match the format it 1115 uses. E.g., GDB tends to use "const char *" as a type name, but 1116 the demangler uses "char const *". */ 1117 canonical = cp_canonicalize_string (type_name); 1118 if (canonical != NULL) 1119 { 1120 make_cleanup (xfree, canonical); 1121 type_name = canonical; 1122 } 1123 1124 typeinfo_type = gnuv3_get_typeid_type (gdbarch); 1125 1126 /* We check for lval_memory because in the "typeid (type-id)" case, 1127 the type is passed via a not_lval value object. */ 1128 if (TYPE_CODE (type) == TYPE_CODE_STRUCT 1129 && value_lval_const (value) == lval_memory 1130 && gnuv3_dynamic_class (type)) 1131 { 1132 struct value *vtable, *typeinfo_value; 1133 CORE_ADDR address = value_address (value) + value_embedded_offset (value); 1134 1135 vtable = gnuv3_get_vtable (gdbarch, type, address); 1136 if (vtable == NULL) 1137 error (_("cannot find typeinfo for object of type '%s'"), type_name); 1138 typeinfo_value = value_field (vtable, vtable_field_type_info); 1139 result = value_ind (value_cast (make_pointer_type (typeinfo_type, NULL), 1140 typeinfo_value)); 1141 } 1142 else 1143 { 1144 char *sym_name; 1145 struct bound_minimal_symbol minsym; 1146 1147 sym_name = concat ("typeinfo for ", type_name, (char *) NULL); 1148 make_cleanup (xfree, sym_name); 1149 minsym = lookup_minimal_symbol (sym_name, NULL, NULL); 1150 1151 if (minsym.minsym == NULL) 1152 error (_("could not find typeinfo symbol for '%s'"), type_name); 1153 1154 result = value_at_lazy (typeinfo_type, BMSYMBOL_VALUE_ADDRESS (minsym)); 1155 } 1156 1157 do_cleanups (cleanup); 1158 return result; 1159 } 1160 1161 /* Implement the 'get_typename_from_type_info' method. */ 1162 1163 static char * 1164 gnuv3_get_typename_from_type_info (struct value *type_info_ptr) 1165 { 1166 struct gdbarch *gdbarch = get_type_arch (value_type (type_info_ptr)); 1167 struct bound_minimal_symbol typeinfo_sym; 1168 CORE_ADDR addr; 1169 const char *symname; 1170 const char *class_name; 1171 const char *atsign; 1172 1173 addr = value_as_address (type_info_ptr); 1174 typeinfo_sym = lookup_minimal_symbol_by_pc (addr); 1175 if (typeinfo_sym.minsym == NULL) 1176 error (_("could not find minimal symbol for typeinfo address %s"), 1177 paddress (gdbarch, addr)); 1178 1179 #define TYPEINFO_PREFIX "typeinfo for " 1180 #define TYPEINFO_PREFIX_LEN (sizeof (TYPEINFO_PREFIX) - 1) 1181 symname = MSYMBOL_DEMANGLED_NAME (typeinfo_sym.minsym); 1182 if (symname == NULL || strncmp (symname, TYPEINFO_PREFIX, 1183 TYPEINFO_PREFIX_LEN)) 1184 error (_("typeinfo symbol '%s' has unexpected name"), 1185 MSYMBOL_LINKAGE_NAME (typeinfo_sym.minsym)); 1186 class_name = symname + TYPEINFO_PREFIX_LEN; 1187 1188 /* Strip off @plt and version suffixes. */ 1189 atsign = strchr (class_name, '@'); 1190 if (atsign != NULL) 1191 return savestring (class_name, atsign - class_name); 1192 return xstrdup (class_name); 1193 } 1194 1195 /* Implement the 'get_type_from_type_info' method. */ 1196 1197 static struct type * 1198 gnuv3_get_type_from_type_info (struct value *type_info_ptr) 1199 { 1200 char *type_name; 1201 struct cleanup *cleanup; 1202 struct value *type_val; 1203 struct expression *expr; 1204 struct type *result; 1205 1206 type_name = gnuv3_get_typename_from_type_info (type_info_ptr); 1207 cleanup = make_cleanup (xfree, type_name); 1208 1209 /* We have to parse the type name, since in general there is not a 1210 symbol for a type. This is somewhat bogus since there may be a 1211 mis-parse. Another approach might be to re-use the demangler's 1212 internal form to reconstruct the type somehow. */ 1213 1214 expr = parse_expression (type_name); 1215 make_cleanup (xfree, expr); 1216 1217 type_val = evaluate_type (expr); 1218 result = value_type (type_val); 1219 1220 do_cleanups (cleanup); 1221 return result; 1222 } 1223 1224 /* Determine if we are currently in a C++ thunk. If so, get the address 1225 of the routine we are thunking to and continue to there instead. */ 1226 1227 static CORE_ADDR 1228 gnuv3_skip_trampoline (struct frame_info *frame, CORE_ADDR stop_pc) 1229 { 1230 CORE_ADDR real_stop_pc, method_stop_pc, func_addr; 1231 struct gdbarch *gdbarch = get_frame_arch (frame); 1232 struct bound_minimal_symbol thunk_sym, fn_sym; 1233 struct obj_section *section; 1234 const char *thunk_name, *fn_name; 1235 1236 real_stop_pc = gdbarch_skip_trampoline_code (gdbarch, frame, stop_pc); 1237 if (real_stop_pc == 0) 1238 real_stop_pc = stop_pc; 1239 1240 /* Find the linker symbol for this potential thunk. */ 1241 thunk_sym = lookup_minimal_symbol_by_pc (real_stop_pc); 1242 section = find_pc_section (real_stop_pc); 1243 if (thunk_sym.minsym == NULL || section == NULL) 1244 return 0; 1245 1246 /* The symbol's demangled name should be something like "virtual 1247 thunk to FUNCTION", where FUNCTION is the name of the function 1248 being thunked to. */ 1249 thunk_name = MSYMBOL_DEMANGLED_NAME (thunk_sym.minsym); 1250 if (thunk_name == NULL || strstr (thunk_name, " thunk to ") == NULL) 1251 return 0; 1252 1253 fn_name = strstr (thunk_name, " thunk to ") + strlen (" thunk to "); 1254 fn_sym = lookup_minimal_symbol (fn_name, NULL, section->objfile); 1255 if (fn_sym.minsym == NULL) 1256 return 0; 1257 1258 method_stop_pc = BMSYMBOL_VALUE_ADDRESS (fn_sym); 1259 1260 /* Some targets have minimal symbols pointing to function descriptors 1261 (powerpc 64 for example). Make sure to retrieve the address 1262 of the real function from the function descriptor before passing on 1263 the address to other layers of GDB. */ 1264 func_addr = gdbarch_convert_from_func_ptr_addr (gdbarch, method_stop_pc, 1265 ¤t_target); 1266 if (func_addr != 0) 1267 method_stop_pc = func_addr; 1268 1269 real_stop_pc = gdbarch_skip_trampoline_code 1270 (gdbarch, frame, method_stop_pc); 1271 if (real_stop_pc == 0) 1272 real_stop_pc = method_stop_pc; 1273 1274 return real_stop_pc; 1275 } 1276 1277 /* Return nonzero if a type should be passed by reference. 1278 1279 The rule in the v3 ABI document comes from section 3.1.1. If the 1280 type has a non-trivial copy constructor or destructor, then the 1281 caller must make a copy (by calling the copy constructor if there 1282 is one or perform the copy itself otherwise), pass the address of 1283 the copy, and then destroy the temporary (if necessary). 1284 1285 For return values with non-trivial copy constructors or 1286 destructors, space will be allocated in the caller, and a pointer 1287 will be passed as the first argument (preceding "this"). 1288 1289 We don't have a bulletproof mechanism for determining whether a 1290 constructor or destructor is trivial. For GCC and DWARF2 debug 1291 information, we can check the artificial flag. 1292 1293 We don't do anything with the constructors or destructors, 1294 but we have to get the argument passing right anyway. */ 1295 static int 1296 gnuv3_pass_by_reference (struct type *type) 1297 { 1298 int fieldnum, fieldelem; 1299 1300 type = check_typedef (type); 1301 1302 /* We're only interested in things that can have methods. */ 1303 if (TYPE_CODE (type) != TYPE_CODE_STRUCT 1304 && TYPE_CODE (type) != TYPE_CODE_UNION) 1305 return 0; 1306 1307 /* A dynamic class has a non-trivial copy constructor. 1308 See c++98 section 12.8 Copying class objects [class.copy]. */ 1309 if (gnuv3_dynamic_class (type)) 1310 return 1; 1311 1312 for (fieldnum = 0; fieldnum < TYPE_NFN_FIELDS (type); fieldnum++) 1313 for (fieldelem = 0; fieldelem < TYPE_FN_FIELDLIST_LENGTH (type, fieldnum); 1314 fieldelem++) 1315 { 1316 struct fn_field *fn = TYPE_FN_FIELDLIST1 (type, fieldnum); 1317 const char *name = TYPE_FN_FIELDLIST_NAME (type, fieldnum); 1318 struct type *fieldtype = TYPE_FN_FIELD_TYPE (fn, fieldelem); 1319 1320 /* If this function is marked as artificial, it is compiler-generated, 1321 and we assume it is trivial. */ 1322 if (TYPE_FN_FIELD_ARTIFICIAL (fn, fieldelem)) 1323 continue; 1324 1325 /* If we've found a destructor, we must pass this by reference. */ 1326 if (name[0] == '~') 1327 return 1; 1328 1329 /* If the mangled name of this method doesn't indicate that it 1330 is a constructor, we're not interested. 1331 1332 FIXME drow/2007-09-23: We could do this using the name of 1333 the method and the name of the class instead of dealing 1334 with the mangled name. We don't have a convenient function 1335 to strip off both leading scope qualifiers and trailing 1336 template arguments yet. */ 1337 if (!is_constructor_name (TYPE_FN_FIELD_PHYSNAME (fn, fieldelem)) 1338 && !TYPE_FN_FIELD_CONSTRUCTOR (fn, fieldelem)) 1339 continue; 1340 1341 /* If this method takes two arguments, and the second argument is 1342 a reference to this class, then it is a copy constructor. */ 1343 if (TYPE_NFIELDS (fieldtype) == 2) 1344 { 1345 struct type *arg_type = TYPE_FIELD_TYPE (fieldtype, 1); 1346 1347 if (TYPE_CODE (arg_type) == TYPE_CODE_REF) 1348 { 1349 struct type *arg_target_type; 1350 1351 arg_target_type = check_typedef (TYPE_TARGET_TYPE (arg_type)); 1352 if (class_types_same_p (arg_target_type, type)) 1353 return 1; 1354 } 1355 } 1356 } 1357 1358 /* Even if all the constructors and destructors were artificial, one 1359 of them may have invoked a non-artificial constructor or 1360 destructor in a base class. If any base class needs to be passed 1361 by reference, so does this class. Similarly for members, which 1362 are constructed whenever this class is. We do not need to worry 1363 about recursive loops here, since we are only looking at members 1364 of complete class type. Also ignore any static members. */ 1365 for (fieldnum = 0; fieldnum < TYPE_NFIELDS (type); fieldnum++) 1366 if (! field_is_static (&TYPE_FIELD (type, fieldnum)) 1367 && gnuv3_pass_by_reference (TYPE_FIELD_TYPE (type, fieldnum))) 1368 return 1; 1369 1370 return 0; 1371 } 1372 1373 static void 1374 init_gnuv3_ops (void) 1375 { 1376 vtable_type_gdbarch_data 1377 = gdbarch_data_register_post_init (build_gdb_vtable_type); 1378 std_type_info_gdbarch_data 1379 = gdbarch_data_register_post_init (build_std_type_info_type); 1380 1381 gnu_v3_abi_ops.shortname = "gnu-v3"; 1382 gnu_v3_abi_ops.longname = "GNU G++ Version 3 ABI"; 1383 gnu_v3_abi_ops.doc = "G++ Version 3 ABI"; 1384 gnu_v3_abi_ops.is_destructor_name = 1385 (enum dtor_kinds (*) (const char *))is_gnu_v3_mangled_dtor; 1386 gnu_v3_abi_ops.is_constructor_name = 1387 (enum ctor_kinds (*) (const char *))is_gnu_v3_mangled_ctor; 1388 gnu_v3_abi_ops.is_vtable_name = gnuv3_is_vtable_name; 1389 gnu_v3_abi_ops.is_operator_name = gnuv3_is_operator_name; 1390 gnu_v3_abi_ops.rtti_type = gnuv3_rtti_type; 1391 gnu_v3_abi_ops.virtual_fn_field = gnuv3_virtual_fn_field; 1392 gnu_v3_abi_ops.baseclass_offset = gnuv3_baseclass_offset; 1393 gnu_v3_abi_ops.print_method_ptr = gnuv3_print_method_ptr; 1394 gnu_v3_abi_ops.method_ptr_size = gnuv3_method_ptr_size; 1395 gnu_v3_abi_ops.make_method_ptr = gnuv3_make_method_ptr; 1396 gnu_v3_abi_ops.method_ptr_to_value = gnuv3_method_ptr_to_value; 1397 gnu_v3_abi_ops.print_vtable = gnuv3_print_vtable; 1398 gnu_v3_abi_ops.get_typeid = gnuv3_get_typeid; 1399 gnu_v3_abi_ops.get_typeid_type = gnuv3_get_typeid_type; 1400 gnu_v3_abi_ops.get_type_from_type_info = gnuv3_get_type_from_type_info; 1401 gnu_v3_abi_ops.get_typename_from_type_info 1402 = gnuv3_get_typename_from_type_info; 1403 gnu_v3_abi_ops.skip_trampoline = gnuv3_skip_trampoline; 1404 gnu_v3_abi_ops.pass_by_reference = gnuv3_pass_by_reference; 1405 } 1406 1407 extern initialize_file_ftype _initialize_gnu_v3_abi; /* -Wmissing-prototypes */ 1408 1409 void 1410 _initialize_gnu_v3_abi (void) 1411 { 1412 init_gnuv3_ops (); 1413 1414 register_cp_abi (&gnu_v3_abi_ops); 1415 set_cp_abi_as_auto_default (gnu_v3_abi_ops.shortname); 1416 } 1417