1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416
|
/* Abstraction of GNU v3 abi.
Contributed by Jim Blandy <jimb@redhat.com>
Copyright (C) 2001-2016 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "value.h"
#include "cp-abi.h"
#include "cp-support.h"
#include "demangle.h"
#include "objfiles.h"
#include "valprint.h"
#include "c-lang.h"
#include "typeprint.h"
static struct cp_abi_ops gnu_v3_abi_ops;
/* A gdbarch key for std::type_info, in the event that it can't be
found in the debug info. */
static struct gdbarch_data *std_type_info_gdbarch_data;
static int
gnuv3_is_vtable_name (const char *name)
{
return startswith (name, "_ZTV");
}
static int
gnuv3_is_operator_name (const char *name)
{
return startswith (name, "operator");
}
/* To help us find the components of a vtable, we build ourselves a
GDB type object representing the vtable structure. Following the
V3 ABI, it goes something like this:
struct gdb_gnu_v3_abi_vtable {
/ * An array of virtual call and virtual base offsets. The real
length of this array depends on the class hierarchy; we use
negative subscripts to access the elements. Yucky, but
better than the alternatives. * /
ptrdiff_t vcall_and_vbase_offsets[0];
/ * The offset from a virtual pointer referring to this table
to the top of the complete object. * /
ptrdiff_t offset_to_top;
/ * The type_info pointer for this class. This is really a
std::type_info *, but GDB doesn't really look at the
type_info object itself, so we don't bother to get the type
exactly right. * /
void *type_info;
/ * Virtual table pointers in objects point here. * /
/ * Virtual function pointers. Like the vcall/vbase array, the
real length of this table depends on the class hierarchy. * /
void (*virtual_functions[0]) ();
};
The catch, of course, is that the exact layout of this table
depends on the ABI --- word size, endianness, alignment, etc. So
the GDB type object is actually a per-architecture kind of thing.
vtable_type_gdbarch_data is a gdbarch per-architecture data pointer
which refers to the struct type * for this structure, laid out
appropriately for the architecture. */
static struct gdbarch_data *vtable_type_gdbarch_data;
/* Human-readable names for the numbers of the fields above. */
enum {
vtable_field_vcall_and_vbase_offsets,
vtable_field_offset_to_top,
vtable_field_type_info,
vtable_field_virtual_functions
};
/* Return a GDB type representing `struct gdb_gnu_v3_abi_vtable',
described above, laid out appropriately for ARCH.
We use this function as the gdbarch per-architecture data
initialization function. */
static void *
build_gdb_vtable_type (struct gdbarch *arch)
{
struct type *t;
struct field *field_list, *field;
int offset;
struct type *void_ptr_type
= builtin_type (arch)->builtin_data_ptr;
struct type *ptr_to_void_fn_type
= builtin_type (arch)->builtin_func_ptr;
/* ARCH can't give us the true ptrdiff_t type, so we guess. */
struct type *ptrdiff_type
= arch_integer_type (arch, gdbarch_ptr_bit (arch), 0, "ptrdiff_t");
/* We assume no padding is necessary, since GDB doesn't know
anything about alignment at the moment. If this assumption bites
us, we should add a gdbarch method which, given a type, returns
the alignment that type requires, and then use that here. */
/* Build the field list. */
field_list = XCNEWVEC (struct field, 4);
field = &field_list[0];
offset = 0;
/* ptrdiff_t vcall_and_vbase_offsets[0]; */
FIELD_NAME (*field) = "vcall_and_vbase_offsets";
FIELD_TYPE (*field) = lookup_array_range_type (ptrdiff_type, 0, -1);
SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT);
offset += TYPE_LENGTH (FIELD_TYPE (*field));
field++;
/* ptrdiff_t offset_to_top; */
FIELD_NAME (*field) = "offset_to_top";
FIELD_TYPE (*field) = ptrdiff_type;
SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT);
offset += TYPE_LENGTH (FIELD_TYPE (*field));
field++;
/* void *type_info; */
FIELD_NAME (*field) = "type_info";
FIELD_TYPE (*field) = void_ptr_type;
SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT);
offset += TYPE_LENGTH (FIELD_TYPE (*field));
field++;
/* void (*virtual_functions[0]) (); */
FIELD_NAME (*field) = "virtual_functions";
FIELD_TYPE (*field) = lookup_array_range_type (ptr_to_void_fn_type, 0, -1);
SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT);
offset += TYPE_LENGTH (FIELD_TYPE (*field));
field++;
/* We assumed in the allocation above that there were four fields. */
gdb_assert (field == (field_list + 4));
t = arch_type (arch, TYPE_CODE_STRUCT, offset, NULL);
TYPE_NFIELDS (t) = field - field_list;
TYPE_FIELDS (t) = field_list;
TYPE_TAG_NAME (t) = "gdb_gnu_v3_abi_vtable";
INIT_CPLUS_SPECIFIC (t);
return make_type_with_address_space (t, TYPE_INSTANCE_FLAG_CODE_SPACE);
}
/* Return the ptrdiff_t type used in the vtable type. */
static struct type *
vtable_ptrdiff_type (struct gdbarch *gdbarch)
{
struct type *vtable_type
= (struct type *) gdbarch_data (gdbarch, vtable_type_gdbarch_data);
/* The "offset_to_top" field has the appropriate (ptrdiff_t) type. */
return TYPE_FIELD_TYPE (vtable_type, vtable_field_offset_to_top);
}
/* Return the offset from the start of the imaginary `struct
gdb_gnu_v3_abi_vtable' object to the vtable's "address point"
(i.e., where objects' virtual table pointers point). */
static int
vtable_address_point_offset (struct gdbarch *gdbarch)
{
struct type *vtable_type
= (struct type *) gdbarch_data (gdbarch, vtable_type_gdbarch_data);
return (TYPE_FIELD_BITPOS (vtable_type, vtable_field_virtual_functions)
/ TARGET_CHAR_BIT);
}
/* Determine whether structure TYPE is a dynamic class. Cache the
result. */
static int
gnuv3_dynamic_class (struct type *type)
{
int fieldnum, fieldelem;
type = check_typedef (type);
gdb_assert (TYPE_CODE (type) == TYPE_CODE_STRUCT
|| TYPE_CODE (type) == TYPE_CODE_UNION);
if (TYPE_CODE (type) == TYPE_CODE_UNION)
return 0;
if (TYPE_CPLUS_DYNAMIC (type))
return TYPE_CPLUS_DYNAMIC (type) == 1;
ALLOCATE_CPLUS_STRUCT_TYPE (type);
for (fieldnum = 0; fieldnum < TYPE_N_BASECLASSES (type); fieldnum++)
if (BASETYPE_VIA_VIRTUAL (type, fieldnum)
|| gnuv3_dynamic_class (TYPE_FIELD_TYPE (type, fieldnum)))
{
TYPE_CPLUS_DYNAMIC (type) = 1;
return 1;
}
for (fieldnum = 0; fieldnum < TYPE_NFN_FIELDS (type); fieldnum++)
for (fieldelem = 0; fieldelem < TYPE_FN_FIELDLIST_LENGTH (type, fieldnum);
fieldelem++)
{
struct fn_field *f = TYPE_FN_FIELDLIST1 (type, fieldnum);
if (TYPE_FN_FIELD_VIRTUAL_P (f, fieldelem))
{
TYPE_CPLUS_DYNAMIC (type) = 1;
return 1;
}
}
TYPE_CPLUS_DYNAMIC (type) = -1;
return 0;
}
/* Find the vtable for a value of CONTAINER_TYPE located at
CONTAINER_ADDR. Return a value of the correct vtable type for this
architecture, or NULL if CONTAINER does not have a vtable. */
static struct value *
gnuv3_get_vtable (struct gdbarch *gdbarch,
struct type *container_type, CORE_ADDR container_addr)
{
struct type *vtable_type
= (struct type *) gdbarch_data (gdbarch, vtable_type_gdbarch_data);
struct type *vtable_pointer_type;
struct value *vtable_pointer;
CORE_ADDR vtable_address;
container_type = check_typedef (container_type);
gdb_assert (TYPE_CODE (container_type) == TYPE_CODE_STRUCT);
/* If this type does not have a virtual table, don't read the first
field. */
if (!gnuv3_dynamic_class (container_type))
return NULL;
/* We do not consult the debug information to find the virtual table.
The ABI specifies that it is always at offset zero in any class,
and debug information may not represent it.
We avoid using value_contents on principle, because the object might
be large. */
/* Find the type "pointer to virtual table". */
vtable_pointer_type = lookup_pointer_type (vtable_type);
/* Load it from the start of the class. */
vtable_pointer = value_at (vtable_pointer_type, container_addr);
vtable_address = value_as_address (vtable_pointer);
/* Correct it to point at the start of the virtual table, rather
than the address point. */
return value_at_lazy (vtable_type,
vtable_address
- vtable_address_point_offset (gdbarch));
}
static struct type *
gnuv3_rtti_type (struct value *value,
int *full_p, LONGEST *top_p, int *using_enc_p)
{
struct gdbarch *gdbarch;
struct type *values_type = check_typedef (value_type (value));
struct value *vtable;
struct minimal_symbol *vtable_symbol;
const char *vtable_symbol_name;
const char *class_name;
struct type *run_time_type;
LONGEST offset_to_top;
const char *atsign;
/* We only have RTTI for class objects. */
if (TYPE_CODE (values_type) != TYPE_CODE_STRUCT)
return NULL;
/* Java doesn't have RTTI following the C++ ABI. */
if (TYPE_CPLUS_REALLY_JAVA (values_type))
return NULL;
/* Determine architecture. */
gdbarch = get_type_arch (values_type);
if (using_enc_p)
*using_enc_p = 0;
vtable = gnuv3_get_vtable (gdbarch, values_type,
value_as_address (value_addr (value)));
if (vtable == NULL)
return NULL;
/* Find the linker symbol for this vtable. */
vtable_symbol
= lookup_minimal_symbol_by_pc (value_address (vtable)
+ value_embedded_offset (vtable)).minsym;
if (! vtable_symbol)
return NULL;
/* The symbol's demangled name should be something like "vtable for
CLASS", where CLASS is the name of the run-time type of VALUE.
If we didn't like this approach, we could instead look in the
type_info object itself to get the class name. But this way
should work just as well, and doesn't read target memory. */
vtable_symbol_name = MSYMBOL_DEMANGLED_NAME (vtable_symbol);
if (vtable_symbol_name == NULL
|| !startswith (vtable_symbol_name, "vtable for "))
{
warning (_("can't find linker symbol for virtual table for `%s' value"),
TYPE_SAFE_NAME (values_type));
if (vtable_symbol_name)
warning (_(" found `%s' instead"), vtable_symbol_name);
return NULL;
}
class_name = vtable_symbol_name + 11;
/* Strip off @plt and version suffixes. */
atsign = strchr (class_name, '@');
if (atsign != NULL)
{
char *copy;
copy = (char *) alloca (atsign - class_name + 1);
memcpy (copy, class_name, atsign - class_name);
copy[atsign - class_name] = '\0';
class_name = copy;
}
/* Try to look up the class name as a type name. */
/* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */
run_time_type = cp_lookup_rtti_type (class_name, NULL);
if (run_time_type == NULL)
return NULL;
/* Get the offset from VALUE to the top of the complete object.
NOTE: this is the reverse of the meaning of *TOP_P. */
offset_to_top
= value_as_long (value_field (vtable, vtable_field_offset_to_top));
if (full_p)
*full_p = (- offset_to_top == value_embedded_offset (value)
&& (TYPE_LENGTH (value_enclosing_type (value))
>= TYPE_LENGTH (run_time_type)));
if (top_p)
*top_p = - offset_to_top;
return run_time_type;
}
/* Return a function pointer for CONTAINER's VTABLE_INDEX'th virtual
function, of type FNTYPE. */
static struct value *
gnuv3_get_virtual_fn (struct gdbarch *gdbarch, struct value *container,
struct type *fntype, int vtable_index)
{
struct value *vtable, *vfn;
/* Every class with virtual functions must have a vtable. */
vtable = gnuv3_get_vtable (gdbarch, value_type (container),
value_as_address (value_addr (container)));
gdb_assert (vtable != NULL);
/* Fetch the appropriate function pointer from the vtable. */
vfn = value_subscript (value_field (vtable, vtable_field_virtual_functions),
vtable_index);
/* If this architecture uses function descriptors directly in the vtable,
then the address of the vtable entry is actually a "function pointer"
(i.e. points to the descriptor). We don't need to scale the index
by the size of a function descriptor; GCC does that before outputing
debug information. */
if (gdbarch_vtable_function_descriptors (gdbarch))
vfn = value_addr (vfn);
/* Cast the function pointer to the appropriate type. */
vfn = value_cast (lookup_pointer_type (fntype), vfn);
return vfn;
}
/* GNU v3 implementation of value_virtual_fn_field. See cp-abi.h
for a description of the arguments. */
static struct value *
gnuv3_virtual_fn_field (struct value **value_p,
struct fn_field *f, int j,
struct type *vfn_base, int offset)
{
struct type *values_type = check_typedef (value_type (*value_p));
struct gdbarch *gdbarch;
/* Some simple sanity checks. */
if (TYPE_CODE (values_type) != TYPE_CODE_STRUCT)
error (_("Only classes can have virtual functions."));
/* Determine architecture. */
gdbarch = get_type_arch (values_type);
/* Cast our value to the base class which defines this virtual
function. This takes care of any necessary `this'
adjustments. */
if (vfn_base != values_type)
*value_p = value_cast (vfn_base, *value_p);
return gnuv3_get_virtual_fn (gdbarch, *value_p, TYPE_FN_FIELD_TYPE (f, j),
TYPE_FN_FIELD_VOFFSET (f, j));
}
/* Compute the offset of the baseclass which is
the INDEXth baseclass of class TYPE,
for value at VALADDR (in host) at ADDRESS (in target).
The result is the offset of the baseclass value relative
to (the address of)(ARG) + OFFSET.
-1 is returned on error. */
static int
gnuv3_baseclass_offset (struct type *type, int index,
const bfd_byte *valaddr, LONGEST embedded_offset,
CORE_ADDR address, const struct value *val)
{
struct gdbarch *gdbarch;
struct type *ptr_type;
struct value *vtable;
struct value *vbase_array;
long int cur_base_offset, base_offset;
/* Determine architecture. */
gdbarch = get_type_arch (type);
ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
/* If it isn't a virtual base, this is easy. The offset is in the
type definition. Likewise for Java, which doesn't really have
virtual inheritance in the C++ sense. */
if (!BASETYPE_VIA_VIRTUAL (type, index) || TYPE_CPLUS_REALLY_JAVA (type))
return TYPE_BASECLASS_BITPOS (type, index) / 8;
/* To access a virtual base, we need to use the vbase offset stored in
our vtable. Recent GCC versions provide this information. If it isn't
available, we could get what we needed from RTTI, or from drawing the
complete inheritance graph based on the debug info. Neither is
worthwhile. */
cur_base_offset = TYPE_BASECLASS_BITPOS (type, index) / 8;
if (cur_base_offset >= - vtable_address_point_offset (gdbarch))
error (_("Expected a negative vbase offset (old compiler?)"));
cur_base_offset = cur_base_offset + vtable_address_point_offset (gdbarch);
if ((- cur_base_offset) % TYPE_LENGTH (ptr_type) != 0)
error (_("Misaligned vbase offset."));
cur_base_offset = cur_base_offset / ((int) TYPE_LENGTH (ptr_type));
vtable = gnuv3_get_vtable (gdbarch, type, address + embedded_offset);
gdb_assert (vtable != NULL);
vbase_array = value_field (vtable, vtable_field_vcall_and_vbase_offsets);
base_offset = value_as_long (value_subscript (vbase_array, cur_base_offset));
return base_offset;
}
/* Locate a virtual method in DOMAIN or its non-virtual base classes
which has virtual table index VOFFSET. The method has an associated
"this" adjustment of ADJUSTMENT bytes. */
static const char *
gnuv3_find_method_in (struct type *domain, CORE_ADDR voffset,
LONGEST adjustment)
{
int i;
/* Search this class first. */
if (adjustment == 0)
{
int len;
len = TYPE_NFN_FIELDS (domain);
for (i = 0; i < len; i++)
{
int len2, j;
struct fn_field *f;
f = TYPE_FN_FIELDLIST1 (domain, i);
len2 = TYPE_FN_FIELDLIST_LENGTH (domain, i);
check_stub_method_group (domain, i);
for (j = 0; j < len2; j++)
if (TYPE_FN_FIELD_VOFFSET (f, j) == voffset)
return TYPE_FN_FIELD_PHYSNAME (f, j);
}
}
/* Next search non-virtual bases. If it's in a virtual base,
we're out of luck. */
for (i = 0; i < TYPE_N_BASECLASSES (domain); i++)
{
int pos;
struct type *basetype;
if (BASETYPE_VIA_VIRTUAL (domain, i))
continue;
pos = TYPE_BASECLASS_BITPOS (domain, i) / 8;
basetype = TYPE_FIELD_TYPE (domain, i);
/* Recurse with a modified adjustment. We don't need to adjust
voffset. */
if (adjustment >= pos && adjustment < pos + TYPE_LENGTH (basetype))
return gnuv3_find_method_in (basetype, voffset, adjustment - pos);
}
return NULL;
}
/* Decode GNU v3 method pointer. */
static int
gnuv3_decode_method_ptr (struct gdbarch *gdbarch,
const gdb_byte *contents,
CORE_ADDR *value_p,
LONGEST *adjustment_p)
{
struct type *funcptr_type = builtin_type (gdbarch)->builtin_func_ptr;
struct type *offset_type = vtable_ptrdiff_type (gdbarch);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
CORE_ADDR ptr_value;
LONGEST voffset, adjustment;
int vbit;
/* Extract the pointer to member. The first element is either a pointer
or a vtable offset. For pointers, we need to use extract_typed_address
to allow the back-end to convert the pointer to a GDB address -- but
vtable offsets we must handle as integers. At this point, we do not
yet know which case we have, so we extract the value under both
interpretations and choose the right one later on. */
ptr_value = extract_typed_address (contents, funcptr_type);
voffset = extract_signed_integer (contents,
TYPE_LENGTH (funcptr_type), byte_order);
contents += TYPE_LENGTH (funcptr_type);
adjustment = extract_signed_integer (contents,
TYPE_LENGTH (offset_type), byte_order);
if (!gdbarch_vbit_in_delta (gdbarch))
{
vbit = voffset & 1;
voffset = voffset ^ vbit;
}
else
{
vbit = adjustment & 1;
adjustment = adjustment >> 1;
}
*value_p = vbit? voffset : ptr_value;
*adjustment_p = adjustment;
return vbit;
}
/* GNU v3 implementation of cplus_print_method_ptr. */
static void
gnuv3_print_method_ptr (const gdb_byte *contents,
struct type *type,
struct ui_file *stream)
{
struct type *self_type = TYPE_SELF_TYPE (type);
struct gdbarch *gdbarch = get_type_arch (self_type);
CORE_ADDR ptr_value;
LONGEST adjustment;
int vbit;
/* Extract the pointer to member. */
vbit = gnuv3_decode_method_ptr (gdbarch, contents, &ptr_value, &adjustment);
/* Check for NULL. */
if (ptr_value == 0 && vbit == 0)
{
fprintf_filtered (stream, "NULL");
return;
}
/* Search for a virtual method. */
if (vbit)
{
CORE_ADDR voffset;
const char *physname;
/* It's a virtual table offset, maybe in this class. Search
for a field with the correct vtable offset. First convert it
to an index, as used in TYPE_FN_FIELD_VOFFSET. */
voffset = ptr_value / TYPE_LENGTH (vtable_ptrdiff_type (gdbarch));
physname = gnuv3_find_method_in (self_type, voffset, adjustment);
/* If we found a method, print that. We don't bother to disambiguate
possible paths to the method based on the adjustment. */
if (physname)
{
char *demangled_name = gdb_demangle (physname,
DMGL_ANSI | DMGL_PARAMS);
fprintf_filtered (stream, "&virtual ");
if (demangled_name == NULL)
fputs_filtered (physname, stream);
else
{
fputs_filtered (demangled_name, stream);
xfree (demangled_name);
}
return;
}
}
else if (ptr_value != 0)
{
/* Found a non-virtual function: print out the type. */
fputs_filtered ("(", stream);
c_print_type (type, "", stream, -1, 0, &type_print_raw_options);
fputs_filtered (") ", stream);
}
/* We didn't find it; print the raw data. */
if (vbit)
{
fprintf_filtered (stream, "&virtual table offset ");
print_longest (stream, 'd', 1, ptr_value);
}
else
{
struct value_print_options opts;
get_user_print_options (&opts);
print_address_demangle (&opts, gdbarch, ptr_value, stream, demangle);
}
if (adjustment)
{
fprintf_filtered (stream, ", this adjustment ");
print_longest (stream, 'd', 1, adjustment);
}
}
/* GNU v3 implementation of cplus_method_ptr_size. */
static int
gnuv3_method_ptr_size (struct type *type)
{
struct gdbarch *gdbarch = get_type_arch (type);
return 2 * TYPE_LENGTH (builtin_type (gdbarch)->builtin_data_ptr);
}
/* GNU v3 implementation of cplus_make_method_ptr. */
static void
gnuv3_make_method_ptr (struct type *type, gdb_byte *contents,
CORE_ADDR value, int is_virtual)
{
struct gdbarch *gdbarch = get_type_arch (type);
int size = TYPE_LENGTH (builtin_type (gdbarch)->builtin_data_ptr);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
/* FIXME drow/2006-12-24: The adjustment of "this" is currently
always zero, since the method pointer is of the correct type.
But if the method pointer came from a base class, this is
incorrect - it should be the offset to the base. The best
fix might be to create the pointer to member pointing at the
base class and cast it to the derived class, but that requires
support for adjusting pointers to members when casting them -
not currently supported by GDB. */
if (!gdbarch_vbit_in_delta (gdbarch))
{
store_unsigned_integer (contents, size, byte_order, value | is_virtual);
store_unsigned_integer (contents + size, size, byte_order, 0);
}
else
{
store_unsigned_integer (contents, size, byte_order, value);
store_unsigned_integer (contents + size, size, byte_order, is_virtual);
}
}
/* GNU v3 implementation of cplus_method_ptr_to_value. */
static struct value *
gnuv3_method_ptr_to_value (struct value **this_p, struct value *method_ptr)
{
struct gdbarch *gdbarch;
const gdb_byte *contents = value_contents (method_ptr);
CORE_ADDR ptr_value;
struct type *self_type, *final_type, *method_type;
LONGEST adjustment;
int vbit;
self_type = TYPE_SELF_TYPE (check_typedef (value_type (method_ptr)));
final_type = lookup_pointer_type (self_type);
method_type = TYPE_TARGET_TYPE (check_typedef (value_type (method_ptr)));
/* Extract the pointer to member. */
gdbarch = get_type_arch (self_type);
vbit = gnuv3_decode_method_ptr (gdbarch, contents, &ptr_value, &adjustment);
/* First convert THIS to match the containing type of the pointer to
member. This cast may adjust the value of THIS. */
*this_p = value_cast (final_type, *this_p);
/* Then apply whatever adjustment is necessary. This creates a somewhat
strange pointer: it claims to have type FINAL_TYPE, but in fact it
might not be a valid FINAL_TYPE. For instance, it might be a
base class of FINAL_TYPE. And if it's not the primary base class,
then printing it out as a FINAL_TYPE object would produce some pretty
garbage.
But we don't really know the type of the first argument in
METHOD_TYPE either, which is why this happens. We can't
dereference this later as a FINAL_TYPE, but once we arrive in the
called method we'll have debugging information for the type of
"this" - and that'll match the value we produce here.
You can provoke this case by casting a Base::* to a Derived::*, for
instance. */
*this_p = value_cast (builtin_type (gdbarch)->builtin_data_ptr, *this_p);
*this_p = value_ptradd (*this_p, adjustment);
*this_p = value_cast (final_type, *this_p);
if (vbit)
{
LONGEST voffset;
voffset = ptr_value / TYPE_LENGTH (vtable_ptrdiff_type (gdbarch));
return gnuv3_get_virtual_fn (gdbarch, value_ind (*this_p),
method_type, voffset);
}
else
return value_from_pointer (lookup_pointer_type (method_type), ptr_value);
}
/* Objects of this type are stored in a hash table and a vector when
printing the vtables for a class. */
struct value_and_voffset
{
/* The value representing the object. */
struct value *value;
/* The maximum vtable offset we've found for any object at this
offset in the outermost object. */
int max_voffset;
};
typedef struct value_and_voffset *value_and_voffset_p;
DEF_VEC_P (value_and_voffset_p);
/* Hash function for value_and_voffset. */
static hashval_t
hash_value_and_voffset (const void *p)
{
const struct value_and_voffset *o = (const struct value_and_voffset *) p;
return value_address (o->value) + value_embedded_offset (o->value);
}
/* Equality function for value_and_voffset. */
static int
eq_value_and_voffset (const void *a, const void *b)
{
const struct value_and_voffset *ova = (const struct value_and_voffset *) a;
const struct value_and_voffset *ovb = (const struct value_and_voffset *) b;
return (value_address (ova->value) + value_embedded_offset (ova->value)
== value_address (ovb->value) + value_embedded_offset (ovb->value));
}
/* qsort comparison function for value_and_voffset. */
static int
compare_value_and_voffset (const void *a, const void *b)
{
const struct value_and_voffset * const *ova
= (const struct value_and_voffset * const *) a;
CORE_ADDR addra = (value_address ((*ova)->value)
+ value_embedded_offset ((*ova)->value));
const struct value_and_voffset * const *ovb
= (const struct value_and_voffset * const *) b;
CORE_ADDR addrb = (value_address ((*ovb)->value)
+ value_embedded_offset ((*ovb)->value));
if (addra < addrb)
return -1;
if (addra > addrb)
return 1;
return 0;
}
/* A helper function used when printing vtables. This determines the
key (most derived) sub-object at each address and also computes the
maximum vtable offset seen for the corresponding vtable. Updates
OFFSET_HASH and OFFSET_VEC with a new value_and_voffset object, if
needed. VALUE is the object to examine. */
static void
compute_vtable_size (htab_t offset_hash,
VEC (value_and_voffset_p) **offset_vec,
struct value *value)
{
int i;
struct type *type = check_typedef (value_type (value));
void **slot;
struct value_and_voffset search_vo, *current_vo;
gdb_assert (TYPE_CODE (type) == TYPE_CODE_STRUCT);
/* If the object is not dynamic, then we are done; as it cannot have
dynamic base types either. */
if (!gnuv3_dynamic_class (type))
return;
/* Update the hash and the vec, if needed. */
search_vo.value = value;
slot = htab_find_slot (offset_hash, &search_vo, INSERT);
if (*slot)
current_vo = (struct value_and_voffset *) *slot;
else
{
current_vo = XNEW (struct value_and_voffset);
current_vo->value = value;
current_vo->max_voffset = -1;
*slot = current_vo;
VEC_safe_push (value_and_voffset_p, *offset_vec, current_vo);
}
/* Update the value_and_voffset object with the highest vtable
offset from this class. */
for (i = 0; i < TYPE_NFN_FIELDS (type); ++i)
{
int j;
struct fn_field *fn = TYPE_FN_FIELDLIST1 (type, i);
for (j = 0; j < TYPE_FN_FIELDLIST_LENGTH (type, i); ++j)
{
if (TYPE_FN_FIELD_VIRTUAL_P (fn, j))
{
int voffset = TYPE_FN_FIELD_VOFFSET (fn, j);
if (voffset > current_vo->max_voffset)
current_vo->max_voffset = voffset;
}
}
}
/* Recurse into base classes. */
for (i = 0; i < TYPE_N_BASECLASSES (type); ++i)
compute_vtable_size (offset_hash, offset_vec, value_field (value, i));
}
/* Helper for gnuv3_print_vtable that prints a single vtable. */
static void
print_one_vtable (struct gdbarch *gdbarch, struct value *value,
int max_voffset,
struct value_print_options *opts)
{
int i;
struct type *type = check_typedef (value_type (value));
struct value *vtable;
CORE_ADDR vt_addr;
vtable = gnuv3_get_vtable (gdbarch, type,
value_address (value)
+ value_embedded_offset (value));
vt_addr = value_address (value_field (vtable,
vtable_field_virtual_functions));
printf_filtered (_("vtable for '%s' @ %s (subobject @ %s):\n"),
TYPE_SAFE_NAME (type),
paddress (gdbarch, vt_addr),
paddress (gdbarch, (value_address (value)
+ value_embedded_offset (value))));
for (i = 0; i <= max_voffset; ++i)
{
/* Initialize it just to avoid a GCC false warning. */
CORE_ADDR addr = 0;
int got_error = 0;
struct value *vfn;
printf_filtered ("[%d]: ", i);
vfn = value_subscript (value_field (vtable,
vtable_field_virtual_functions),
i);
if (gdbarch_vtable_function_descriptors (gdbarch))
vfn = value_addr (vfn);
TRY
{
addr = value_as_address (vfn);
}
CATCH (ex, RETURN_MASK_ERROR)
{
printf_filtered (_("<error: %s>"), ex.message);
got_error = 1;
}
END_CATCH
if (!got_error)
print_function_pointer_address (opts, gdbarch, addr, gdb_stdout);
printf_filtered ("\n");
}
}
/* Implementation of the print_vtable method. */
static void
gnuv3_print_vtable (struct value *value)
{
struct gdbarch *gdbarch;
struct type *type;
struct value *vtable;
struct value_print_options opts;
htab_t offset_hash;
struct cleanup *cleanup;
VEC (value_and_voffset_p) *result_vec = NULL;
struct value_and_voffset *iter;
int i, count;
value = coerce_ref (value);
type = check_typedef (value_type (value));
if (TYPE_CODE (type) == TYPE_CODE_PTR)
{
value = value_ind (value);
type = check_typedef (value_type (value));
}
get_user_print_options (&opts);
/* Respect 'set print object'. */
if (opts.objectprint)
{
value = value_full_object (value, NULL, 0, 0, 0);
type = check_typedef (value_type (value));
}
gdbarch = get_type_arch (type);
vtable = NULL;
if (TYPE_CODE (type) == TYPE_CODE_STRUCT)
vtable = gnuv3_get_vtable (gdbarch, type,
value_as_address (value_addr (value)));
if (!vtable)
{
printf_filtered (_("This object does not have a virtual function table\n"));
return;
}
offset_hash = htab_create_alloc (1, hash_value_and_voffset,
eq_value_and_voffset,
xfree, xcalloc, xfree);
cleanup = make_cleanup_htab_delete (offset_hash);
make_cleanup (VEC_cleanup (value_and_voffset_p), &result_vec);
compute_vtable_size (offset_hash, &result_vec, value);
qsort (VEC_address (value_and_voffset_p, result_vec),
VEC_length (value_and_voffset_p, result_vec),
sizeof (value_and_voffset_p),
compare_value_and_voffset);
count = 0;
for (i = 0; VEC_iterate (value_and_voffset_p, result_vec, i, iter); ++i)
{
if (iter->max_voffset >= 0)
{
if (count > 0)
printf_filtered ("\n");
print_one_vtable (gdbarch, iter->value, iter->max_voffset, &opts);
++count;
}
}
do_cleanups (cleanup);
}
/* Return a GDB type representing `struct std::type_info', laid out
appropriately for ARCH.
We use this function as the gdbarch per-architecture data
initialization function. */
static void *
build_std_type_info_type (struct gdbarch *arch)
{
struct type *t;
struct field *field_list, *field;
int offset;
struct type *void_ptr_type
= builtin_type (arch)->builtin_data_ptr;
struct type *char_type
= builtin_type (arch)->builtin_char;
struct type *char_ptr_type
= make_pointer_type (make_cv_type (1, 0, char_type, NULL), NULL);
field_list = XCNEWVEC (struct field, 2);
field = &field_list[0];
offset = 0;
/* The vtable. */
FIELD_NAME (*field) = "_vptr.type_info";
FIELD_TYPE (*field) = void_ptr_type;
SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT);
offset += TYPE_LENGTH (FIELD_TYPE (*field));
field++;
/* The name. */
FIELD_NAME (*field) = "__name";
FIELD_TYPE (*field) = char_ptr_type;
SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT);
offset += TYPE_LENGTH (FIELD_TYPE (*field));
field++;
gdb_assert (field == (field_list + 2));
t = arch_type (arch, TYPE_CODE_STRUCT, offset, NULL);
TYPE_NFIELDS (t) = field - field_list;
TYPE_FIELDS (t) = field_list;
TYPE_TAG_NAME (t) = "gdb_gnu_v3_type_info";
INIT_CPLUS_SPECIFIC (t);
return t;
}
/* Implement the 'get_typeid_type' method. */
static struct type *
gnuv3_get_typeid_type (struct gdbarch *gdbarch)
{
struct symbol *typeinfo;
struct type *typeinfo_type;
typeinfo = lookup_symbol ("std::type_info", NULL, STRUCT_DOMAIN,
NULL).symbol;
if (typeinfo == NULL)
typeinfo_type
= (struct type *) gdbarch_data (gdbarch, std_type_info_gdbarch_data);
else
typeinfo_type = SYMBOL_TYPE (typeinfo);
return typeinfo_type;
}
/* Implement the 'get_typeid' method. */
static struct value *
gnuv3_get_typeid (struct value *value)
{
struct type *typeinfo_type;
struct type *type;
struct gdbarch *gdbarch;
struct cleanup *cleanup;
struct value *result;
char *type_name, *canonical;
/* We have to handle values a bit trickily here, to allow this code
to work properly with non_lvalue values that are really just
disguised types. */
if (value_lval_const (value) == lval_memory)
value = coerce_ref (value);
type = check_typedef (value_type (value));
/* In the non_lvalue case, a reference might have slipped through
here. */
if (TYPE_CODE (type) == TYPE_CODE_REF)
type = check_typedef (TYPE_TARGET_TYPE (type));
/* Ignore top-level cv-qualifiers. */
type = make_cv_type (0, 0, type, NULL);
gdbarch = get_type_arch (type);
type_name = type_to_string (type);
if (type_name == NULL)
error (_("cannot find typeinfo for unnamed type"));
cleanup = make_cleanup (xfree, type_name);
/* We need to canonicalize the type name here, because we do lookups
using the demangled name, and so we must match the format it
uses. E.g., GDB tends to use "const char *" as a type name, but
the demangler uses "char const *". */
canonical = cp_canonicalize_string (type_name);
if (canonical != NULL)
{
make_cleanup (xfree, canonical);
type_name = canonical;
}
typeinfo_type = gnuv3_get_typeid_type (gdbarch);
/* We check for lval_memory because in the "typeid (type-id)" case,
the type is passed via a not_lval value object. */
if (TYPE_CODE (type) == TYPE_CODE_STRUCT
&& value_lval_const (value) == lval_memory
&& gnuv3_dynamic_class (type))
{
struct value *vtable, *typeinfo_value;
CORE_ADDR address = value_address (value) + value_embedded_offset (value);
vtable = gnuv3_get_vtable (gdbarch, type, address);
if (vtable == NULL)
error (_("cannot find typeinfo for object of type '%s'"), type_name);
typeinfo_value = value_field (vtable, vtable_field_type_info);
result = value_ind (value_cast (make_pointer_type (typeinfo_type, NULL),
typeinfo_value));
}
else
{
char *sym_name;
struct bound_minimal_symbol minsym;
sym_name = concat ("typeinfo for ", type_name, (char *) NULL);
make_cleanup (xfree, sym_name);
minsym = lookup_minimal_symbol (sym_name, NULL, NULL);
if (minsym.minsym == NULL)
error (_("could not find typeinfo symbol for '%s'"), type_name);
result = value_at_lazy (typeinfo_type, BMSYMBOL_VALUE_ADDRESS (minsym));
}
do_cleanups (cleanup);
return result;
}
/* Implement the 'get_typename_from_type_info' method. */
static char *
gnuv3_get_typename_from_type_info (struct value *type_info_ptr)
{
struct gdbarch *gdbarch = get_type_arch (value_type (type_info_ptr));
struct bound_minimal_symbol typeinfo_sym;
CORE_ADDR addr;
const char *symname;
const char *class_name;
const char *atsign;
addr = value_as_address (type_info_ptr);
typeinfo_sym = lookup_minimal_symbol_by_pc (addr);
if (typeinfo_sym.minsym == NULL)
error (_("could not find minimal symbol for typeinfo address %s"),
paddress (gdbarch, addr));
#define TYPEINFO_PREFIX "typeinfo for "
#define TYPEINFO_PREFIX_LEN (sizeof (TYPEINFO_PREFIX) - 1)
symname = MSYMBOL_DEMANGLED_NAME (typeinfo_sym.minsym);
if (symname == NULL || strncmp (symname, TYPEINFO_PREFIX,
TYPEINFO_PREFIX_LEN))
error (_("typeinfo symbol '%s' has unexpected name"),
MSYMBOL_LINKAGE_NAME (typeinfo_sym.minsym));
class_name = symname + TYPEINFO_PREFIX_LEN;
/* Strip off @plt and version suffixes. */
atsign = strchr (class_name, '@');
if (atsign != NULL)
return savestring (class_name, atsign - class_name);
return xstrdup (class_name);
}
/* Implement the 'get_type_from_type_info' method. */
static struct type *
gnuv3_get_type_from_type_info (struct value *type_info_ptr)
{
char *type_name;
struct cleanup *cleanup;
struct value *type_val;
struct expression *expr;
struct type *result;
type_name = gnuv3_get_typename_from_type_info (type_info_ptr);
cleanup = make_cleanup (xfree, type_name);
/* We have to parse the type name, since in general there is not a
symbol for a type. This is somewhat bogus since there may be a
mis-parse. Another approach might be to re-use the demangler's
internal form to reconstruct the type somehow. */
expr = parse_expression (type_name);
make_cleanup (xfree, expr);
type_val = evaluate_type (expr);
result = value_type (type_val);
do_cleanups (cleanup);
return result;
}
/* Determine if we are currently in a C++ thunk. If so, get the address
of the routine we are thunking to and continue to there instead. */
static CORE_ADDR
gnuv3_skip_trampoline (struct frame_info *frame, CORE_ADDR stop_pc)
{
CORE_ADDR real_stop_pc, method_stop_pc, func_addr;
struct gdbarch *gdbarch = get_frame_arch (frame);
struct bound_minimal_symbol thunk_sym, fn_sym;
struct obj_section *section;
const char *thunk_name, *fn_name;
real_stop_pc = gdbarch_skip_trampoline_code (gdbarch, frame, stop_pc);
if (real_stop_pc == 0)
real_stop_pc = stop_pc;
/* Find the linker symbol for this potential thunk. */
thunk_sym = lookup_minimal_symbol_by_pc (real_stop_pc);
section = find_pc_section (real_stop_pc);
if (thunk_sym.minsym == NULL || section == NULL)
return 0;
/* The symbol's demangled name should be something like "virtual
thunk to FUNCTION", where FUNCTION is the name of the function
being thunked to. */
thunk_name = MSYMBOL_DEMANGLED_NAME (thunk_sym.minsym);
if (thunk_name == NULL || strstr (thunk_name, " thunk to ") == NULL)
return 0;
fn_name = strstr (thunk_name, " thunk to ") + strlen (" thunk to ");
fn_sym = lookup_minimal_symbol (fn_name, NULL, section->objfile);
if (fn_sym.minsym == NULL)
return 0;
method_stop_pc = BMSYMBOL_VALUE_ADDRESS (fn_sym);
/* Some targets have minimal symbols pointing to function descriptors
(powerpc 64 for example). Make sure to retrieve the address
of the real function from the function descriptor before passing on
the address to other layers of GDB. */
func_addr = gdbarch_convert_from_func_ptr_addr (gdbarch, method_stop_pc,
¤t_target);
if (func_addr != 0)
method_stop_pc = func_addr;
real_stop_pc = gdbarch_skip_trampoline_code
(gdbarch, frame, method_stop_pc);
if (real_stop_pc == 0)
real_stop_pc = method_stop_pc;
return real_stop_pc;
}
/* Return nonzero if a type should be passed by reference.
The rule in the v3 ABI document comes from section 3.1.1. If the
type has a non-trivial copy constructor or destructor, then the
caller must make a copy (by calling the copy constructor if there
is one or perform the copy itself otherwise), pass the address of
the copy, and then destroy the temporary (if necessary).
For return values with non-trivial copy constructors or
destructors, space will be allocated in the caller, and a pointer
will be passed as the first argument (preceding "this").
We don't have a bulletproof mechanism for determining whether a
constructor or destructor is trivial. For GCC and DWARF2 debug
information, we can check the artificial flag.
We don't do anything with the constructors or destructors,
but we have to get the argument passing right anyway. */
static int
gnuv3_pass_by_reference (struct type *type)
{
int fieldnum, fieldelem;
type = check_typedef (type);
/* We're only interested in things that can have methods. */
if (TYPE_CODE (type) != TYPE_CODE_STRUCT
&& TYPE_CODE (type) != TYPE_CODE_UNION)
return 0;
/* A dynamic class has a non-trivial copy constructor.
See c++98 section 12.8 Copying class objects [class.copy]. */
if (gnuv3_dynamic_class (type))
return 1;
for (fieldnum = 0; fieldnum < TYPE_NFN_FIELDS (type); fieldnum++)
for (fieldelem = 0; fieldelem < TYPE_FN_FIELDLIST_LENGTH (type, fieldnum);
fieldelem++)
{
struct fn_field *fn = TYPE_FN_FIELDLIST1 (type, fieldnum);
const char *name = TYPE_FN_FIELDLIST_NAME (type, fieldnum);
struct type *fieldtype = TYPE_FN_FIELD_TYPE (fn, fieldelem);
/* If this function is marked as artificial, it is compiler-generated,
and we assume it is trivial. */
if (TYPE_FN_FIELD_ARTIFICIAL (fn, fieldelem))
continue;
/* If we've found a destructor, we must pass this by reference. */
if (name[0] == '~')
return 1;
/* If the mangled name of this method doesn't indicate that it
is a constructor, we're not interested.
FIXME drow/2007-09-23: We could do this using the name of
the method and the name of the class instead of dealing
with the mangled name. We don't have a convenient function
to strip off both leading scope qualifiers and trailing
template arguments yet. */
if (!is_constructor_name (TYPE_FN_FIELD_PHYSNAME (fn, fieldelem))
&& !TYPE_FN_FIELD_CONSTRUCTOR (fn, fieldelem))
continue;
/* If this method takes two arguments, and the second argument is
a reference to this class, then it is a copy constructor. */
if (TYPE_NFIELDS (fieldtype) == 2)
{
struct type *arg_type = TYPE_FIELD_TYPE (fieldtype, 1);
if (TYPE_CODE (arg_type) == TYPE_CODE_REF)
{
struct type *arg_target_type;
arg_target_type = check_typedef (TYPE_TARGET_TYPE (arg_type));
if (class_types_same_p (arg_target_type, type))
return 1;
}
}
}
/* Even if all the constructors and destructors were artificial, one
of them may have invoked a non-artificial constructor or
destructor in a base class. If any base class needs to be passed
by reference, so does this class. Similarly for members, which
are constructed whenever this class is. We do not need to worry
about recursive loops here, since we are only looking at members
of complete class type. Also ignore any static members. */
for (fieldnum = 0; fieldnum < TYPE_NFIELDS (type); fieldnum++)
if (! field_is_static (&TYPE_FIELD (type, fieldnum))
&& gnuv3_pass_by_reference (TYPE_FIELD_TYPE (type, fieldnum)))
return 1;
return 0;
}
static void
init_gnuv3_ops (void)
{
vtable_type_gdbarch_data
= gdbarch_data_register_post_init (build_gdb_vtable_type);
std_type_info_gdbarch_data
= gdbarch_data_register_post_init (build_std_type_info_type);
gnu_v3_abi_ops.shortname = "gnu-v3";
gnu_v3_abi_ops.longname = "GNU G++ Version 3 ABI";
gnu_v3_abi_ops.doc = "G++ Version 3 ABI";
gnu_v3_abi_ops.is_destructor_name =
(enum dtor_kinds (*) (const char *))is_gnu_v3_mangled_dtor;
gnu_v3_abi_ops.is_constructor_name =
(enum ctor_kinds (*) (const char *))is_gnu_v3_mangled_ctor;
gnu_v3_abi_ops.is_vtable_name = gnuv3_is_vtable_name;
gnu_v3_abi_ops.is_operator_name = gnuv3_is_operator_name;
gnu_v3_abi_ops.rtti_type = gnuv3_rtti_type;
gnu_v3_abi_ops.virtual_fn_field = gnuv3_virtual_fn_field;
gnu_v3_abi_ops.baseclass_offset = gnuv3_baseclass_offset;
gnu_v3_abi_ops.print_method_ptr = gnuv3_print_method_ptr;
gnu_v3_abi_ops.method_ptr_size = gnuv3_method_ptr_size;
gnu_v3_abi_ops.make_method_ptr = gnuv3_make_method_ptr;
gnu_v3_abi_ops.method_ptr_to_value = gnuv3_method_ptr_to_value;
gnu_v3_abi_ops.print_vtable = gnuv3_print_vtable;
gnu_v3_abi_ops.get_typeid = gnuv3_get_typeid;
gnu_v3_abi_ops.get_typeid_type = gnuv3_get_typeid_type;
gnu_v3_abi_ops.get_type_from_type_info = gnuv3_get_type_from_type_info;
gnu_v3_abi_ops.get_typename_from_type_info
= gnuv3_get_typename_from_type_info;
gnu_v3_abi_ops.skip_trampoline = gnuv3_skip_trampoline;
gnu_v3_abi_ops.pass_by_reference = gnuv3_pass_by_reference;
}
extern initialize_file_ftype _initialize_gnu_v3_abi; /* -Wmissing-prototypes */
void
_initialize_gnu_v3_abi (void)
{
init_gnuv3_ops ();
register_cp_abi (&gnu_v3_abi_ops);
set_cp_abi_as_auto_default (gnu_v3_abi_ops.shortname);
}
|