1 /* Abstraction of GNU v3 abi.
2 Contributed by Jim Blandy <jimb@redhat.com>
4 Copyright (C) 2001, 2002, 2003, 2005, 2006, 2007, 2008
5 Free Software Foundation, Inc.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
25 #include "cp-support.h"
30 #include "gdb_assert.h"
31 #include "gdb_string.h"
33 static struct cp_abi_ops gnu_v3_abi_ops;
36 gnuv3_is_vtable_name (const char *name)
38 return strncmp (name, "_ZTV", 4) == 0;
42 gnuv3_is_operator_name (const char *name)
44 return strncmp (name, "operator", 8) == 0;
48 /* Determine architecture of class DOMAIN. This architecture is used
49 to query C++ ABI details (types, method pointer layout, etc.).
51 Note that we assume DOMAIN must have been allocated with an OBJFILE;
52 GDB does not provide any built-in class types. Thus we use the
53 architecture of that OBJFILE to define the C++ ABI. */
55 static struct gdbarch *
56 get_class_arch (struct type *domain)
58 gdb_assert (TYPE_CODE (domain) == TYPE_CODE_CLASS);
59 gdb_assert (TYPE_OBJFILE (domain) != NULL);
60 return get_objfile_arch (TYPE_OBJFILE (domain));
63 /* To help us find the components of a vtable, we build ourselves a
64 GDB type object representing the vtable structure. Following the
65 V3 ABI, it goes something like this:
67 struct gdb_gnu_v3_abi_vtable {
69 / * An array of virtual call and virtual base offsets. The real
70 length of this array depends on the class hierarchy; we use
71 negative subscripts to access the elements. Yucky, but
72 better than the alternatives. * /
73 ptrdiff_t vcall_and_vbase_offsets[0];
75 / * The offset from a virtual pointer referring to this table
76 to the top of the complete object. * /
77 ptrdiff_t offset_to_top;
79 / * The type_info pointer for this class. This is really a
80 std::type_info *, but GDB doesn't really look at the
81 type_info object itself, so we don't bother to get the type
85 / * Virtual table pointers in objects point here. * /
87 / * Virtual function pointers. Like the vcall/vbase array, the
88 real length of this table depends on the class hierarchy. * /
89 void (*virtual_functions[0]) ();
93 The catch, of course, is that the exact layout of this table
94 depends on the ABI --- word size, endianness, alignment, etc. So
95 the GDB type object is actually a per-architecture kind of thing.
97 vtable_type_gdbarch_data is a gdbarch per-architecture data pointer
98 which refers to the struct type * for this structure, laid out
99 appropriately for the architecture. */
100 static struct gdbarch_data *vtable_type_gdbarch_data;
103 /* Human-readable names for the numbers of the fields above. */
105 vtable_field_vcall_and_vbase_offsets,
106 vtable_field_offset_to_top,
107 vtable_field_type_info,
108 vtable_field_virtual_functions
112 /* Return a GDB type representing `struct gdb_gnu_v3_abi_vtable',
113 described above, laid out appropriately for ARCH.
115 We use this function as the gdbarch per-architecture data
116 initialization function. */
118 build_gdb_vtable_type (struct gdbarch *arch)
121 struct field *field_list, *field;
124 struct type *void_ptr_type
125 = builtin_type (arch)->builtin_data_ptr;
126 struct type *ptr_to_void_fn_type
127 = builtin_type (arch)->builtin_func_ptr;
129 /* ARCH can't give us the true ptrdiff_t type, so we guess. */
130 struct type *ptrdiff_type
131 = init_type (TYPE_CODE_INT,
132 gdbarch_ptr_bit (arch) / TARGET_CHAR_BIT, 0,
135 /* We assume no padding is necessary, since GDB doesn't know
136 anything about alignment at the moment. If this assumption bites
137 us, we should add a gdbarch method which, given a type, returns
138 the alignment that type requires, and then use that here. */
140 /* Build the field list. */
141 field_list = xmalloc (sizeof (struct field [4]));
142 memset (field_list, 0, sizeof (struct field [4]));
143 field = &field_list[0];
146 /* ptrdiff_t vcall_and_vbase_offsets[0]; */
147 FIELD_NAME (*field) = "vcall_and_vbase_offsets";
149 = create_array_type (0, ptrdiff_type,
150 create_range_type (0, builtin_type_int32, 0, -1));
151 FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT;
152 offset += TYPE_LENGTH (FIELD_TYPE (*field));
155 /* ptrdiff_t offset_to_top; */
156 FIELD_NAME (*field) = "offset_to_top";
157 FIELD_TYPE (*field) = ptrdiff_type;
158 FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT;
159 offset += TYPE_LENGTH (FIELD_TYPE (*field));
162 /* void *type_info; */
163 FIELD_NAME (*field) = "type_info";
164 FIELD_TYPE (*field) = void_ptr_type;
165 FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT;
166 offset += TYPE_LENGTH (FIELD_TYPE (*field));
169 /* void (*virtual_functions[0]) (); */
170 FIELD_NAME (*field) = "virtual_functions";
172 = create_array_type (0, ptr_to_void_fn_type,
173 create_range_type (0, builtin_type_int32, 0, -1));
174 FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT;
175 offset += TYPE_LENGTH (FIELD_TYPE (*field));
178 /* We assumed in the allocation above that there were four fields. */
179 gdb_assert (field == (field_list + 4));
181 t = init_type (TYPE_CODE_STRUCT, offset, 0, 0, 0);
182 TYPE_NFIELDS (t) = field - field_list;
183 TYPE_FIELDS (t) = field_list;
184 TYPE_TAG_NAME (t) = "gdb_gnu_v3_abi_vtable";
190 /* Return the offset from the start of the imaginary `struct
191 gdb_gnu_v3_abi_vtable' object to the vtable's "address point"
192 (i.e., where objects' virtual table pointers point). */
194 vtable_address_point_offset (struct gdbarch *gdbarch)
196 struct type *vtable_type = gdbarch_data (gdbarch, vtable_type_gdbarch_data);
198 return (TYPE_FIELD_BITPOS (vtable_type, vtable_field_virtual_functions)
204 gnuv3_rtti_type (struct value *value,
205 int *full_p, int *top_p, int *using_enc_p)
207 struct gdbarch *gdbarch;
208 struct type *vtable_type;
209 struct type *values_type = check_typedef (value_type (value));
210 CORE_ADDR vtable_address;
211 struct value *vtable;
212 struct minimal_symbol *vtable_symbol;
213 const char *vtable_symbol_name;
214 const char *class_name;
215 struct type *run_time_type;
216 struct type *base_type;
217 LONGEST offset_to_top;
218 struct type *values_type_vptr_basetype;
219 int values_type_vptr_fieldno;
221 /* We only have RTTI for class objects. */
222 if (TYPE_CODE (values_type) != TYPE_CODE_CLASS)
225 /* This routine may be called for Java types that do not have
226 a proper objfile. Just return NULL for those. */
227 if (!TYPE_OBJFILE (values_type)
228 || !TYPE_OBJFILE (values_type)->obfd)
231 /* Determine architecture. */
232 gdbarch = get_class_arch (values_type);
233 vtable_type = gdbarch_data (gdbarch, vtable_type_gdbarch_data);
235 /* If we can't find the virtual table pointer for values_type, we
236 can't find the RTTI. */
237 values_type_vptr_fieldno = get_vptr_fieldno (values_type,
238 &values_type_vptr_basetype);
239 if (values_type_vptr_fieldno == -1)
245 /* Fetch VALUE's virtual table pointer, and tweak it to point at
246 an instance of our imaginary gdb_gnu_v3_abi_vtable structure. */
247 base_type = check_typedef (values_type_vptr_basetype);
248 if (values_type != base_type)
250 value = value_cast (base_type, value);
255 = value_as_address (value_field (value, values_type_vptr_fieldno));
257 = value_at_lazy (vtable_type,
258 vtable_address - vtable_address_point_offset (gdbarch));
260 /* Find the linker symbol for this vtable. */
262 = lookup_minimal_symbol_by_pc (VALUE_ADDRESS (vtable)
263 + value_offset (vtable)
264 + value_embedded_offset (vtable));
268 /* The symbol's demangled name should be something like "vtable for
269 CLASS", where CLASS is the name of the run-time type of VALUE.
270 If we didn't like this approach, we could instead look in the
271 type_info object itself to get the class name. But this way
272 should work just as well, and doesn't read target memory. */
273 vtable_symbol_name = SYMBOL_DEMANGLED_NAME (vtable_symbol);
274 if (vtable_symbol_name == NULL
275 || strncmp (vtable_symbol_name, "vtable for ", 11))
277 warning (_("can't find linker symbol for virtual table for `%s' value"),
278 TYPE_NAME (values_type));
279 if (vtable_symbol_name)
280 warning (_(" found `%s' instead"), vtable_symbol_name);
283 class_name = vtable_symbol_name + 11;
285 /* Try to look up the class name as a type name. */
286 /* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */
287 run_time_type = cp_lookup_rtti_type (class_name, NULL);
288 if (run_time_type == NULL)
291 /* Get the offset from VALUE to the top of the complete object.
292 NOTE: this is the reverse of the meaning of *TOP_P. */
294 = value_as_long (value_field (vtable, vtable_field_offset_to_top));
297 *full_p = (- offset_to_top == value_embedded_offset (value)
298 && (TYPE_LENGTH (value_enclosing_type (value))
299 >= TYPE_LENGTH (run_time_type)));
301 *top_p = - offset_to_top;
303 return run_time_type;
306 /* Find the vtable for CONTAINER and return a value of the correct
307 vtable type for this architecture. */
309 static struct value *
310 gnuv3_get_vtable (struct gdbarch *gdbarch, struct value *container)
312 struct type *vtable_type = gdbarch_data (gdbarch, vtable_type_gdbarch_data);
313 struct type *vtable_pointer_type;
314 struct value *vtable_pointer;
315 CORE_ADDR vtable_pointer_address, vtable_address;
317 /* We do not consult the debug information to find the virtual table.
318 The ABI specifies that it is always at offset zero in any class,
319 and debug information may not represent it. We won't issue an
320 error if there's a class with virtual functions but no virtual table
321 pointer, but something's already gone seriously wrong if that
324 We avoid using value_contents on principle, because the object might
327 /* Find the type "pointer to virtual table". */
328 vtable_pointer_type = lookup_pointer_type (vtable_type);
330 /* Load it from the start of the class. */
331 vtable_pointer_address = value_as_address (value_addr (container));
332 vtable_pointer = value_at (vtable_pointer_type, vtable_pointer_address);
333 vtable_address = value_as_address (vtable_pointer);
335 /* Correct it to point at the start of the virtual table, rather
336 than the address point. */
337 return value_at_lazy (vtable_type,
338 vtable_address - vtable_address_point_offset (gdbarch));
341 /* Return a function pointer for CONTAINER's VTABLE_INDEX'th virtual
342 function, of type FNTYPE. */
344 static struct value *
345 gnuv3_get_virtual_fn (struct gdbarch *gdbarch, struct value *container,
346 struct type *fntype, int vtable_index)
348 struct value *vtable = gnuv3_get_vtable (gdbarch, container);
351 /* Fetch the appropriate function pointer from the vtable. */
352 vfn = value_subscript (value_field (vtable, vtable_field_virtual_functions),
353 value_from_longest (builtin_type_int32, vtable_index));
355 /* If this architecture uses function descriptors directly in the vtable,
356 then the address of the vtable entry is actually a "function pointer"
357 (i.e. points to the descriptor). We don't need to scale the index
358 by the size of a function descriptor; GCC does that before outputing
359 debug information. */
360 if (gdbarch_vtable_function_descriptors (gdbarch))
361 vfn = value_addr (vfn);
363 /* Cast the function pointer to the appropriate type. */
364 vfn = value_cast (lookup_pointer_type (fntype), vfn);
369 /* GNU v3 implementation of value_virtual_fn_field. See cp-abi.h
370 for a description of the arguments. */
372 static struct value *
373 gnuv3_virtual_fn_field (struct value **value_p,
374 struct fn_field *f, int j,
375 struct type *vfn_base, int offset)
377 struct type *values_type = check_typedef (value_type (*value_p));
378 struct gdbarch *gdbarch;
380 /* Some simple sanity checks. */
381 if (TYPE_CODE (values_type) != TYPE_CODE_CLASS)
382 error (_("Only classes can have virtual functions."));
384 /* Determine architecture. */
385 gdbarch = get_class_arch (values_type);
387 /* Cast our value to the base class which defines this virtual
388 function. This takes care of any necessary `this'
390 if (vfn_base != values_type)
391 *value_p = value_cast (vfn_base, *value_p);
393 return gnuv3_get_virtual_fn (gdbarch, *value_p, TYPE_FN_FIELD_TYPE (f, j),
394 TYPE_FN_FIELD_VOFFSET (f, j));
397 /* Compute the offset of the baseclass which is
398 the INDEXth baseclass of class TYPE,
399 for value at VALADDR (in host) at ADDRESS (in target).
400 The result is the offset of the baseclass value relative
401 to (the address of)(ARG) + OFFSET.
403 -1 is returned on error. */
405 gnuv3_baseclass_offset (struct type *type, int index, const bfd_byte *valaddr,
408 struct gdbarch *gdbarch;
409 struct type *vtable_type;
410 struct type *ptr_type;
411 struct value *vtable;
412 struct type *vbasetype;
413 struct value *offset_val, *vbase_array;
414 CORE_ADDR vtable_address;
415 long int cur_base_offset, base_offset;
416 int vbasetype_vptr_fieldno;
418 /* Determine architecture. */
419 gdbarch = get_class_arch (type);
420 vtable_type = gdbarch_data (gdbarch, vtable_type_gdbarch_data);
421 ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
423 /* If it isn't a virtual base, this is easy. The offset is in the
425 if (!BASETYPE_VIA_VIRTUAL (type, index))
426 return TYPE_BASECLASS_BITPOS (type, index) / 8;
428 /* To access a virtual base, we need to use the vbase offset stored in
429 our vtable. Recent GCC versions provide this information. If it isn't
430 available, we could get what we needed from RTTI, or from drawing the
431 complete inheritance graph based on the debug info. Neither is
433 cur_base_offset = TYPE_BASECLASS_BITPOS (type, index) / 8;
434 if (cur_base_offset >= - vtable_address_point_offset (gdbarch))
435 error (_("Expected a negative vbase offset (old compiler?)"));
437 cur_base_offset = cur_base_offset + vtable_address_point_offset (gdbarch);
438 if ((- cur_base_offset) % TYPE_LENGTH (ptr_type) != 0)
439 error (_("Misaligned vbase offset."));
440 cur_base_offset = cur_base_offset / ((int) TYPE_LENGTH (ptr_type));
442 /* We're now looking for the cur_base_offset'th entry (negative index)
443 in the vcall_and_vbase_offsets array. We used to cast the object to
444 its TYPE_VPTR_BASETYPE, and reference the vtable as TYPE_VPTR_FIELDNO;
445 however, that cast can not be done without calling baseclass_offset again
446 if the TYPE_VPTR_BASETYPE is a virtual base class, as described in the
447 v3 C++ ABI Section 2.4.I.2.b. Fortunately the ABI guarantees that the
448 vtable pointer will be located at the beginning of the object, so we can
449 bypass the casting. Verify that the TYPE_VPTR_FIELDNO is in fact at the
450 start of whichever baseclass it resides in, as a sanity measure - iff
451 we have debugging information for that baseclass. */
453 vbasetype = TYPE_VPTR_BASETYPE (type);
454 vbasetype_vptr_fieldno = get_vptr_fieldno (vbasetype, NULL);
456 if (vbasetype_vptr_fieldno >= 0
457 && TYPE_FIELD_BITPOS (vbasetype, vbasetype_vptr_fieldno) != 0)
458 error (_("Illegal vptr offset in class %s"),
459 TYPE_NAME (vbasetype) ? TYPE_NAME (vbasetype) : "<unknown>");
461 vtable_address = value_as_address (value_at_lazy (ptr_type, address));
463 = value_at_lazy (vtable_type,
464 vtable_address - vtable_address_point_offset (gdbarch));
465 offset_val = value_from_longest (builtin_type_int32, cur_base_offset);
466 vbase_array = value_field (vtable, vtable_field_vcall_and_vbase_offsets);
467 base_offset = value_as_long (value_subscript (vbase_array, offset_val));
471 /* Locate a virtual method in DOMAIN or its non-virtual base classes
472 which has virtual table index VOFFSET. The method has an associated
473 "this" adjustment of ADJUSTMENT bytes. */
476 gnuv3_find_method_in (struct type *domain, CORE_ADDR voffset,
480 const char *physname;
482 /* Search this class first. */
488 len = TYPE_NFN_FIELDS (domain);
489 for (i = 0; i < len; i++)
494 f = TYPE_FN_FIELDLIST1 (domain, i);
495 len2 = TYPE_FN_FIELDLIST_LENGTH (domain, i);
497 check_stub_method_group (domain, i);
498 for (j = 0; j < len2; j++)
499 if (TYPE_FN_FIELD_VOFFSET (f, j) == voffset)
500 return TYPE_FN_FIELD_PHYSNAME (f, j);
504 /* Next search non-virtual bases. If it's in a virtual base,
505 we're out of luck. */
506 for (i = 0; i < TYPE_N_BASECLASSES (domain); i++)
509 struct type *basetype;
511 if (BASETYPE_VIA_VIRTUAL (domain, i))
514 pos = TYPE_BASECLASS_BITPOS (domain, i) / 8;
515 basetype = TYPE_FIELD_TYPE (domain, i);
516 /* Recurse with a modified adjustment. We don't need to adjust
518 if (adjustment >= pos && adjustment < pos + TYPE_LENGTH (basetype))
519 return gnuv3_find_method_in (basetype, voffset, adjustment - pos);
525 /* Decode GNU v3 method pointer. */
528 gnuv3_decode_method_ptr (struct gdbarch *gdbarch,
529 const gdb_byte *contents,
531 LONGEST *adjustment_p)
533 struct type *funcptr_type = builtin_type (gdbarch)->builtin_func_ptr;
534 struct type *offset_type = builtin_type (gdbarch)->builtin_long;
536 LONGEST voffset, adjustment;
539 /* Extract the pointer to member. The first element is either a pointer
540 or a vtable offset. For pointers, we need to use extract_typed_address
541 to allow the back-end to convert the pointer to a GDB address -- but
542 vtable offsets we must handle as integers. At this point, we do not
543 yet know which case we have, so we extract the value under both
544 interpretations and choose the right one later on. */
545 ptr_value = extract_typed_address (contents, funcptr_type);
546 voffset = extract_signed_integer (contents, TYPE_LENGTH (funcptr_type));
547 contents += TYPE_LENGTH (funcptr_type);
548 adjustment = extract_signed_integer (contents, TYPE_LENGTH (offset_type));
550 if (!gdbarch_vbit_in_delta (gdbarch))
553 voffset = voffset ^ vbit;
557 vbit = adjustment & 1;
558 adjustment = adjustment >> 1;
561 *value_p = vbit? voffset : ptr_value;
562 *adjustment_p = adjustment;
566 /* GNU v3 implementation of cplus_print_method_ptr. */
569 gnuv3_print_method_ptr (const gdb_byte *contents,
571 struct ui_file *stream)
573 struct type *domain = TYPE_DOMAIN_TYPE (type);
574 struct gdbarch *gdbarch = get_class_arch (domain);
579 /* Extract the pointer to member. */
580 vbit = gnuv3_decode_method_ptr (gdbarch, contents, &ptr_value, &adjustment);
582 /* Check for NULL. */
583 if (ptr_value == 0 && vbit == 0)
585 fprintf_filtered (stream, "NULL");
589 /* Search for a virtual method. */
593 const char *physname;
595 /* It's a virtual table offset, maybe in this class. Search
596 for a field with the correct vtable offset. First convert it
597 to an index, as used in TYPE_FN_FIELD_VOFFSET. */
598 voffset = ptr_value / TYPE_LENGTH (builtin_type (gdbarch)->builtin_long);
600 physname = gnuv3_find_method_in (domain, voffset, adjustment);
602 /* If we found a method, print that. We don't bother to disambiguate
603 possible paths to the method based on the adjustment. */
606 char *demangled_name = cplus_demangle (physname,
607 DMGL_ANSI | DMGL_PARAMS);
608 if (demangled_name != NULL)
610 fprintf_filtered (stream, "&virtual ");
611 fputs_filtered (demangled_name, stream);
612 xfree (demangled_name);
618 /* We didn't find it; print the raw data. */
621 fprintf_filtered (stream, "&virtual table offset ");
622 print_longest (stream, 'd', 1, ptr_value);
625 print_address_demangle (ptr_value, stream, demangle);
629 fprintf_filtered (stream, ", this adjustment ");
630 print_longest (stream, 'd', 1, adjustment);
634 /* GNU v3 implementation of cplus_method_ptr_size. */
637 gnuv3_method_ptr_size (struct type *type)
639 struct type *domain_type = check_typedef (TYPE_DOMAIN_TYPE (type));
640 struct gdbarch *gdbarch = get_class_arch (domain_type);
641 return 2 * TYPE_LENGTH (builtin_type (gdbarch)->builtin_data_ptr);
644 /* GNU v3 implementation of cplus_make_method_ptr. */
647 gnuv3_make_method_ptr (struct type *type, gdb_byte *contents,
648 CORE_ADDR value, int is_virtual)
650 struct type *domain_type = check_typedef (TYPE_DOMAIN_TYPE (type));
651 struct gdbarch *gdbarch = get_class_arch (domain_type);
652 int size = TYPE_LENGTH (builtin_type (gdbarch)->builtin_data_ptr);
654 /* FIXME drow/2006-12-24: The adjustment of "this" is currently
655 always zero, since the method pointer is of the correct type.
656 But if the method pointer came from a base class, this is
657 incorrect - it should be the offset to the base. The best
658 fix might be to create the pointer to member pointing at the
659 base class and cast it to the derived class, but that requires
660 support for adjusting pointers to members when casting them -
661 not currently supported by GDB. */
663 if (!gdbarch_vbit_in_delta (gdbarch))
665 store_unsigned_integer (contents, size, value | is_virtual);
666 store_unsigned_integer (contents + size, size, 0);
670 store_unsigned_integer (contents, size, value);
671 store_unsigned_integer (contents + size, size, is_virtual);
675 /* GNU v3 implementation of cplus_method_ptr_to_value. */
677 static struct value *
678 gnuv3_method_ptr_to_value (struct value **this_p, struct value *method_ptr)
680 struct gdbarch *gdbarch;
681 const gdb_byte *contents = value_contents (method_ptr);
683 struct type *domain_type, *final_type, *method_type;
685 struct value *adjval;
688 domain_type = TYPE_DOMAIN_TYPE (check_typedef (value_type (method_ptr)));
689 final_type = lookup_pointer_type (domain_type);
691 method_type = TYPE_TARGET_TYPE (check_typedef (value_type (method_ptr)));
693 /* Extract the pointer to member. */
694 gdbarch = get_class_arch (domain_type);
695 vbit = gnuv3_decode_method_ptr (gdbarch, contents, &ptr_value, &adjustment);
697 /* First convert THIS to match the containing type of the pointer to
698 member. This cast may adjust the value of THIS. */
699 *this_p = value_cast (final_type, *this_p);
701 /* Then apply whatever adjustment is necessary. This creates a somewhat
702 strange pointer: it claims to have type FINAL_TYPE, but in fact it
703 might not be a valid FINAL_TYPE. For instance, it might be a
704 base class of FINAL_TYPE. And if it's not the primary base class,
705 then printing it out as a FINAL_TYPE object would produce some pretty
708 But we don't really know the type of the first argument in
709 METHOD_TYPE either, which is why this happens. We can't
710 dereference this later as a FINAL_TYPE, but once we arrive in the
711 called method we'll have debugging information for the type of
712 "this" - and that'll match the value we produce here.
714 You can provoke this case by casting a Base::* to a Derived::*, for
716 *this_p = value_cast (builtin_type (gdbarch)->builtin_data_ptr, *this_p);
717 adjval = value_from_longest (builtin_type (gdbarch)->builtin_long,
719 *this_p = value_ptradd (*this_p, adjval);
720 *this_p = value_cast (final_type, *this_p);
725 voffset = ptr_value / TYPE_LENGTH (builtin_type (gdbarch)->builtin_long);
726 return gnuv3_get_virtual_fn (gdbarch, value_ind (*this_p),
727 method_type, voffset);
730 return value_from_pointer (lookup_pointer_type (method_type), ptr_value);
733 /* Determine if we are currently in a C++ thunk. If so, get the address
734 of the routine we are thunking to and continue to there instead. */
737 gnuv3_skip_trampoline (struct frame_info *frame, CORE_ADDR stop_pc)
739 CORE_ADDR real_stop_pc, method_stop_pc;
740 struct gdbarch *gdbarch = get_frame_arch (frame);
741 struct minimal_symbol *thunk_sym, *fn_sym;
742 struct obj_section *section;
743 char *thunk_name, *fn_name;
745 real_stop_pc = gdbarch_skip_trampoline_code (gdbarch, frame, stop_pc);
746 if (real_stop_pc == 0)
747 real_stop_pc = stop_pc;
749 /* Find the linker symbol for this potential thunk. */
750 thunk_sym = lookup_minimal_symbol_by_pc (real_stop_pc);
751 section = find_pc_section (real_stop_pc);
752 if (thunk_sym == NULL || section == NULL)
755 /* The symbol's demangled name should be something like "virtual
756 thunk to FUNCTION", where FUNCTION is the name of the function
758 thunk_name = SYMBOL_DEMANGLED_NAME (thunk_sym);
759 if (thunk_name == NULL || strstr (thunk_name, " thunk to ") == NULL)
762 fn_name = strstr (thunk_name, " thunk to ") + strlen (" thunk to ");
763 fn_sym = lookup_minimal_symbol (fn_name, NULL, section->objfile);
767 method_stop_pc = SYMBOL_VALUE_ADDRESS (fn_sym);
768 real_stop_pc = gdbarch_skip_trampoline_code
769 (gdbarch, frame, method_stop_pc);
770 if (real_stop_pc == 0)
771 real_stop_pc = method_stop_pc;
776 /* Return nonzero if a type should be passed by reference.
778 The rule in the v3 ABI document comes from section 3.1.1. If the
779 type has a non-trivial copy constructor or destructor, then the
780 caller must make a copy (by calling the copy constructor if there
781 is one or perform the copy itself otherwise), pass the address of
782 the copy, and then destroy the temporary (if necessary).
784 For return values with non-trivial copy constructors or
785 destructors, space will be allocated in the caller, and a pointer
786 will be passed as the first argument (preceding "this").
788 We don't have a bulletproof mechanism for determining whether a
789 constructor or destructor is trivial. For GCC and DWARF2 debug
790 information, we can check the artificial flag.
792 We don't do anything with the constructors or destructors,
793 but we have to get the argument passing right anyway. */
795 gnuv3_pass_by_reference (struct type *type)
797 int fieldnum, fieldelem;
799 CHECK_TYPEDEF (type);
801 /* We're only interested in things that can have methods. */
802 if (TYPE_CODE (type) != TYPE_CODE_STRUCT
803 && TYPE_CODE (type) != TYPE_CODE_CLASS
804 && TYPE_CODE (type) != TYPE_CODE_UNION)
807 for (fieldnum = 0; fieldnum < TYPE_NFN_FIELDS (type); fieldnum++)
808 for (fieldelem = 0; fieldelem < TYPE_FN_FIELDLIST_LENGTH (type, fieldnum);
811 struct fn_field *fn = TYPE_FN_FIELDLIST1 (type, fieldnum);
812 char *name = TYPE_FN_FIELDLIST_NAME (type, fieldnum);
813 struct type *fieldtype = TYPE_FN_FIELD_TYPE (fn, fieldelem);
815 /* If this function is marked as artificial, it is compiler-generated,
816 and we assume it is trivial. */
817 if (TYPE_FN_FIELD_ARTIFICIAL (fn, fieldelem))
820 /* If we've found a destructor, we must pass this by reference. */
824 /* If the mangled name of this method doesn't indicate that it
825 is a constructor, we're not interested.
827 FIXME drow/2007-09-23: We could do this using the name of
828 the method and the name of the class instead of dealing
829 with the mangled name. We don't have a convenient function
830 to strip off both leading scope qualifiers and trailing
831 template arguments yet. */
832 if (!is_constructor_name (TYPE_FN_FIELD_PHYSNAME (fn, fieldelem)))
835 /* If this method takes two arguments, and the second argument is
836 a reference to this class, then it is a copy constructor. */
837 if (TYPE_NFIELDS (fieldtype) == 2
838 && TYPE_CODE (TYPE_FIELD_TYPE (fieldtype, 1)) == TYPE_CODE_REF
839 && check_typedef (TYPE_TARGET_TYPE (TYPE_FIELD_TYPE (fieldtype, 1))) == type)
843 /* Even if all the constructors and destructors were artificial, one
844 of them may have invoked a non-artificial constructor or
845 destructor in a base class. If any base class needs to be passed
846 by reference, so does this class. Similarly for members, which
847 are constructed whenever this class is. We do not need to worry
848 about recursive loops here, since we are only looking at members
849 of complete class type. */
850 for (fieldnum = 0; fieldnum < TYPE_NFIELDS (type); fieldnum++)
851 if (gnuv3_pass_by_reference (TYPE_FIELD_TYPE (type, fieldnum)))
858 init_gnuv3_ops (void)
860 vtable_type_gdbarch_data = gdbarch_data_register_post_init (build_gdb_vtable_type);
862 gnu_v3_abi_ops.shortname = "gnu-v3";
863 gnu_v3_abi_ops.longname = "GNU G++ Version 3 ABI";
864 gnu_v3_abi_ops.doc = "G++ Version 3 ABI";
865 gnu_v3_abi_ops.is_destructor_name =
866 (enum dtor_kinds (*) (const char *))is_gnu_v3_mangled_dtor;
867 gnu_v3_abi_ops.is_constructor_name =
868 (enum ctor_kinds (*) (const char *))is_gnu_v3_mangled_ctor;
869 gnu_v3_abi_ops.is_vtable_name = gnuv3_is_vtable_name;
870 gnu_v3_abi_ops.is_operator_name = gnuv3_is_operator_name;
871 gnu_v3_abi_ops.rtti_type = gnuv3_rtti_type;
872 gnu_v3_abi_ops.virtual_fn_field = gnuv3_virtual_fn_field;
873 gnu_v3_abi_ops.baseclass_offset = gnuv3_baseclass_offset;
874 gnu_v3_abi_ops.print_method_ptr = gnuv3_print_method_ptr;
875 gnu_v3_abi_ops.method_ptr_size = gnuv3_method_ptr_size;
876 gnu_v3_abi_ops.make_method_ptr = gnuv3_make_method_ptr;
877 gnu_v3_abi_ops.method_ptr_to_value = gnuv3_method_ptr_to_value;
878 gnu_v3_abi_ops.skip_trampoline = gnuv3_skip_trampoline;
879 gnu_v3_abi_ops.pass_by_reference = gnuv3_pass_by_reference;
882 extern initialize_file_ftype _initialize_gnu_v3_abi; /* -Wmissing-prototypes */
885 _initialize_gnu_v3_abi (void)
889 register_cp_abi (&gnu_v3_abi_ops);