1602 lines
50 KiB
C
1602 lines
50 KiB
C
/* Abstraction of GNU v3 abi.
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Contributed by Jim Blandy <jimb@redhat.com>
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Copyright (C) 2001-2022 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "value.h"
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#include "cp-abi.h"
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#include "cp-support.h"
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#include "demangle.h"
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#include "dwarf2.h"
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#include "objfiles.h"
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#include "valprint.h"
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#include "c-lang.h"
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#include "typeprint.h"
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#include <algorithm>
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#include "cli/cli-style.h"
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#include "dwarf2/loc.h"
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#include "inferior.h"
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static struct cp_abi_ops gnu_v3_abi_ops;
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/* A gdbarch key for std::type_info, in the event that it can't be
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found in the debug info. */
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static struct gdbarch_data *std_type_info_gdbarch_data;
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static int
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gnuv3_is_vtable_name (const char *name)
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{
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return startswith (name, "_ZTV");
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}
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static int
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gnuv3_is_operator_name (const char *name)
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{
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return startswith (name, CP_OPERATOR_STR);
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}
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/* To help us find the components of a vtable, we build ourselves a
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GDB type object representing the vtable structure. Following the
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V3 ABI, it goes something like this:
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struct gdb_gnu_v3_abi_vtable {
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/ * An array of virtual call and virtual base offsets. The real
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length of this array depends on the class hierarchy; we use
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negative subscripts to access the elements. Yucky, but
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better than the alternatives. * /
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ptrdiff_t vcall_and_vbase_offsets[0];
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/ * The offset from a virtual pointer referring to this table
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to the top of the complete object. * /
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ptrdiff_t offset_to_top;
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/ * The type_info pointer for this class. This is really a
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std::type_info *, but GDB doesn't really look at the
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type_info object itself, so we don't bother to get the type
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exactly right. * /
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void *type_info;
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/ * Virtual table pointers in objects point here. * /
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/ * Virtual function pointers. Like the vcall/vbase array, the
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real length of this table depends on the class hierarchy. * /
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void (*virtual_functions[0]) ();
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};
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The catch, of course, is that the exact layout of this table
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depends on the ABI --- word size, endianness, alignment, etc. So
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the GDB type object is actually a per-architecture kind of thing.
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vtable_type_gdbarch_data is a gdbarch per-architecture data pointer
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which refers to the struct type * for this structure, laid out
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appropriately for the architecture. */
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static struct gdbarch_data *vtable_type_gdbarch_data;
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/* Human-readable names for the numbers of the fields above. */
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enum {
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vtable_field_vcall_and_vbase_offsets,
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vtable_field_offset_to_top,
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vtable_field_type_info,
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vtable_field_virtual_functions
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};
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/* Return a GDB type representing `struct gdb_gnu_v3_abi_vtable',
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described above, laid out appropriately for ARCH.
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We use this function as the gdbarch per-architecture data
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initialization function. */
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static void *
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build_gdb_vtable_type (struct gdbarch *arch)
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{
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struct type *t;
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struct field *field_list, *field;
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int offset;
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struct type *void_ptr_type
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= builtin_type (arch)->builtin_data_ptr;
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struct type *ptr_to_void_fn_type
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= builtin_type (arch)->builtin_func_ptr;
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/* ARCH can't give us the true ptrdiff_t type, so we guess. */
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struct type *ptrdiff_type
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= arch_integer_type (arch, gdbarch_ptr_bit (arch), 0, "ptrdiff_t");
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/* We assume no padding is necessary, since GDB doesn't know
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anything about alignment at the moment. If this assumption bites
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us, we should add a gdbarch method which, given a type, returns
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the alignment that type requires, and then use that here. */
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/* Build the field list. */
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field_list = XCNEWVEC (struct field, 4);
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field = &field_list[0];
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offset = 0;
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/* ptrdiff_t vcall_and_vbase_offsets[0]; */
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field->set_name ("vcall_and_vbase_offsets");
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field->set_type (lookup_array_range_type (ptrdiff_type, 0, -1));
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field->set_loc_bitpos (offset * TARGET_CHAR_BIT);
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offset += TYPE_LENGTH (field->type ());
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field++;
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/* ptrdiff_t offset_to_top; */
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field->set_name ("offset_to_top");
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field->set_type (ptrdiff_type);
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field->set_loc_bitpos (offset * TARGET_CHAR_BIT);
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offset += TYPE_LENGTH (field->type ());
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field++;
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/* void *type_info; */
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field->set_name ("type_info");
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field->set_type (void_ptr_type);
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field->set_loc_bitpos (offset * TARGET_CHAR_BIT);
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offset += TYPE_LENGTH (field->type ());
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field++;
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/* void (*virtual_functions[0]) (); */
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field->set_name ("virtual_functions");
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field->set_type (lookup_array_range_type (ptr_to_void_fn_type, 0, -1));
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field->set_loc_bitpos (offset * TARGET_CHAR_BIT);
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offset += TYPE_LENGTH (field->type ());
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field++;
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/* We assumed in the allocation above that there were four fields. */
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gdb_assert (field == (field_list + 4));
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t = arch_type (arch, TYPE_CODE_STRUCT, offset * TARGET_CHAR_BIT, NULL);
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t->set_num_fields (field - field_list);
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t->set_fields (field_list);
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t->set_name ("gdb_gnu_v3_abi_vtable");
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INIT_CPLUS_SPECIFIC (t);
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return make_type_with_address_space (t, TYPE_INSTANCE_FLAG_CODE_SPACE);
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}
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/* Return the ptrdiff_t type used in the vtable type. */
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static struct type *
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vtable_ptrdiff_type (struct gdbarch *gdbarch)
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{
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struct type *vtable_type
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= (struct type *) gdbarch_data (gdbarch, vtable_type_gdbarch_data);
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/* The "offset_to_top" field has the appropriate (ptrdiff_t) type. */
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return vtable_type->field (vtable_field_offset_to_top).type ();
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}
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/* Return the offset from the start of the imaginary `struct
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gdb_gnu_v3_abi_vtable' object to the vtable's "address point"
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(i.e., where objects' virtual table pointers point). */
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static int
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vtable_address_point_offset (struct gdbarch *gdbarch)
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{
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struct type *vtable_type
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= (struct type *) gdbarch_data (gdbarch, vtable_type_gdbarch_data);
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return (vtable_type->field (vtable_field_virtual_functions).loc_bitpos ()
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/ TARGET_CHAR_BIT);
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}
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/* Determine whether structure TYPE is a dynamic class. Cache the
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result. */
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static int
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gnuv3_dynamic_class (struct type *type)
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{
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int fieldnum, fieldelem;
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type = check_typedef (type);
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gdb_assert (type->code () == TYPE_CODE_STRUCT
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|| type->code () == TYPE_CODE_UNION);
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if (type->code () == TYPE_CODE_UNION)
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return 0;
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if (TYPE_CPLUS_DYNAMIC (type))
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return TYPE_CPLUS_DYNAMIC (type) == 1;
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ALLOCATE_CPLUS_STRUCT_TYPE (type);
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for (fieldnum = 0; fieldnum < TYPE_N_BASECLASSES (type); fieldnum++)
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if (BASETYPE_VIA_VIRTUAL (type, fieldnum)
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|| gnuv3_dynamic_class (type->field (fieldnum).type ()))
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{
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TYPE_CPLUS_DYNAMIC (type) = 1;
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return 1;
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}
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for (fieldnum = 0; fieldnum < TYPE_NFN_FIELDS (type); fieldnum++)
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for (fieldelem = 0; fieldelem < TYPE_FN_FIELDLIST_LENGTH (type, fieldnum);
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fieldelem++)
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{
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struct fn_field *f = TYPE_FN_FIELDLIST1 (type, fieldnum);
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if (TYPE_FN_FIELD_VIRTUAL_P (f, fieldelem))
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{
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TYPE_CPLUS_DYNAMIC (type) = 1;
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return 1;
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}
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}
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TYPE_CPLUS_DYNAMIC (type) = -1;
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return 0;
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}
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/* Find the vtable for a value of CONTAINER_TYPE located at
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CONTAINER_ADDR. Return a value of the correct vtable type for this
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architecture, or NULL if CONTAINER does not have a vtable. */
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static struct value *
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gnuv3_get_vtable (struct gdbarch *gdbarch,
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struct type *container_type, CORE_ADDR container_addr)
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{
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struct type *vtable_type
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= (struct type *) gdbarch_data (gdbarch, vtable_type_gdbarch_data);
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struct type *vtable_pointer_type;
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struct value *vtable_pointer;
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CORE_ADDR vtable_address;
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container_type = check_typedef (container_type);
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gdb_assert (container_type->code () == TYPE_CODE_STRUCT);
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/* If this type does not have a virtual table, don't read the first
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field. */
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if (!gnuv3_dynamic_class (container_type))
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return NULL;
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/* We do not consult the debug information to find the virtual table.
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The ABI specifies that it is always at offset zero in any class,
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and debug information may not represent it.
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We avoid using value_contents on principle, because the object might
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be large. */
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/* Find the type "pointer to virtual table". */
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vtable_pointer_type = lookup_pointer_type (vtable_type);
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/* Load it from the start of the class. */
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vtable_pointer = value_at (vtable_pointer_type, container_addr);
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vtable_address = value_as_address (vtable_pointer);
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/* Correct it to point at the start of the virtual table, rather
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than the address point. */
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return value_at_lazy (vtable_type,
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vtable_address
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- vtable_address_point_offset (gdbarch));
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}
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static struct type *
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gnuv3_rtti_type (struct value *value,
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int *full_p, LONGEST *top_p, int *using_enc_p)
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{
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struct gdbarch *gdbarch;
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struct type *values_type = check_typedef (value_type (value));
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struct value *vtable;
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struct minimal_symbol *vtable_symbol;
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const char *vtable_symbol_name;
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const char *class_name;
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struct type *run_time_type;
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LONGEST offset_to_top;
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const char *atsign;
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/* We only have RTTI for dynamic class objects. */
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if (values_type->code () != TYPE_CODE_STRUCT
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|| !gnuv3_dynamic_class (values_type))
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return NULL;
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/* Determine architecture. */
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gdbarch = values_type->arch ();
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if (using_enc_p)
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*using_enc_p = 0;
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vtable = gnuv3_get_vtable (gdbarch, values_type,
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value_as_address (value_addr (value)));
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if (vtable == NULL)
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return NULL;
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/* Find the linker symbol for this vtable. */
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vtable_symbol
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= lookup_minimal_symbol_by_pc (value_address (vtable)
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+ value_embedded_offset (vtable)).minsym;
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if (! vtable_symbol)
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return NULL;
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/* The symbol's demangled name should be something like "vtable for
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CLASS", where CLASS is the name of the run-time type of VALUE.
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If we didn't like this approach, we could instead look in the
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type_info object itself to get the class name. But this way
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should work just as well, and doesn't read target memory. */
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vtable_symbol_name = vtable_symbol->demangled_name ();
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if (vtable_symbol_name == NULL
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|| !startswith (vtable_symbol_name, "vtable for "))
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{
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warning (_("can't find linker symbol for virtual table for `%s' value"),
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TYPE_SAFE_NAME (values_type));
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if (vtable_symbol_name)
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warning (_(" found `%s' instead"), vtable_symbol_name);
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return NULL;
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}
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class_name = vtable_symbol_name + 11;
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/* Strip off @plt and version suffixes. */
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atsign = strchr (class_name, '@');
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if (atsign != NULL)
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{
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char *copy;
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copy = (char *) alloca (atsign - class_name + 1);
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memcpy (copy, class_name, atsign - class_name);
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copy[atsign - class_name] = '\0';
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class_name = copy;
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}
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/* Try to look up the class name as a type name. */
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/* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */
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run_time_type = cp_lookup_rtti_type (class_name, NULL);
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if (run_time_type == NULL)
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return NULL;
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/* Get the offset from VALUE to the top of the complete object.
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NOTE: this is the reverse of the meaning of *TOP_P. */
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offset_to_top
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= value_as_long (value_field (vtable, vtable_field_offset_to_top));
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if (full_p)
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*full_p = (- offset_to_top == value_embedded_offset (value)
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&& (TYPE_LENGTH (value_enclosing_type (value))
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>= TYPE_LENGTH (run_time_type)));
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if (top_p)
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*top_p = - offset_to_top;
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return run_time_type;
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}
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/* Return a function pointer for CONTAINER's VTABLE_INDEX'th virtual
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function, of type FNTYPE. */
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static struct value *
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gnuv3_get_virtual_fn (struct gdbarch *gdbarch, struct value *container,
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struct type *fntype, int vtable_index)
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{
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struct value *vtable, *vfn;
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/* Every class with virtual functions must have a vtable. */
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vtable = gnuv3_get_vtable (gdbarch, value_type (container),
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value_as_address (value_addr (container)));
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gdb_assert (vtable != NULL);
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/* Fetch the appropriate function pointer from the vtable. */
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vfn = value_subscript (value_field (vtable, vtable_field_virtual_functions),
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vtable_index);
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/* If this architecture uses function descriptors directly in the vtable,
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then the address of the vtable entry is actually a "function pointer"
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(i.e. points to the descriptor). We don't need to scale the index
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by the size of a function descriptor; GCC does that before outputting
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debug information. */
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if (gdbarch_vtable_function_descriptors (gdbarch))
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vfn = value_addr (vfn);
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/* Cast the function pointer to the appropriate type. */
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vfn = value_cast (lookup_pointer_type (fntype), vfn);
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return vfn;
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}
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/* GNU v3 implementation of value_virtual_fn_field. See cp-abi.h
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for a description of the arguments. */
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static struct value *
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gnuv3_virtual_fn_field (struct value **value_p,
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struct fn_field *f, int j,
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struct type *vfn_base, int offset)
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{
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struct type *values_type = check_typedef (value_type (*value_p));
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struct gdbarch *gdbarch;
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/* Some simple sanity checks. */
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if (values_type->code () != TYPE_CODE_STRUCT)
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error (_("Only classes can have virtual functions."));
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/* Determine architecture. */
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gdbarch = values_type->arch ();
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/* Cast our value to the base class which defines this virtual
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function. This takes care of any necessary `this'
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adjustments. */
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if (vfn_base != values_type)
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*value_p = value_cast (vfn_base, *value_p);
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return gnuv3_get_virtual_fn (gdbarch, *value_p, TYPE_FN_FIELD_TYPE (f, j),
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TYPE_FN_FIELD_VOFFSET (f, j));
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}
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/* Compute the offset of the baseclass which is
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the INDEXth baseclass of class TYPE,
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for value at VALADDR (in host) at ADDRESS (in target).
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The result is the offset of the baseclass value relative
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to (the address of)(ARG) + OFFSET.
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-1 is returned on error. */
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static int
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gnuv3_baseclass_offset (struct type *type, int index,
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const bfd_byte *valaddr, LONGEST embedded_offset,
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CORE_ADDR address, const struct value *val)
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{
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struct gdbarch *gdbarch;
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struct type *ptr_type;
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struct value *vtable;
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struct value *vbase_array;
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long int cur_base_offset, base_offset;
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/* Determine architecture. */
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gdbarch = type->arch ();
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ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
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/* If it isn't a virtual base, this is easy. The offset is in the
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type definition. */
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if (!BASETYPE_VIA_VIRTUAL (type, index))
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return TYPE_BASECLASS_BITPOS (type, index) / 8;
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/* If we have a DWARF expression for the offset, evaluate it. */
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if (type->field (index).loc_kind () == FIELD_LOC_KIND_DWARF_BLOCK)
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{
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struct dwarf2_property_baton baton;
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baton.property_type
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= lookup_pointer_type (type->field (index).type ());
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baton.locexpr = *type->field (index).loc_dwarf_block ();
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struct dynamic_prop prop;
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prop.set_locexpr (&baton);
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struct property_addr_info addr_stack;
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addr_stack.type = type;
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/* Note that we don't set "valaddr" here. Doing so causes
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regressions. FIXME. */
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addr_stack.addr = address + embedded_offset;
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addr_stack.next = nullptr;
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CORE_ADDR result;
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if (dwarf2_evaluate_property (&prop, nullptr, &addr_stack, &result,
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{addr_stack.addr}))
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return (int) (result - addr_stack.addr);
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}
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/* To access a virtual base, we need to use the vbase offset stored in
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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 = domain->field (i).type ();
|
|
/* 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 = self_type->arch ();
|
|
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)
|
|
{
|
|
gdb_printf (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)
|
|
{
|
|
gdb::unique_xmalloc_ptr<char> demangled_name
|
|
= gdb_demangle (physname, DMGL_ANSI | DMGL_PARAMS);
|
|
|
|
gdb_printf (stream, "&virtual ");
|
|
if (demangled_name == NULL)
|
|
gdb_puts (physname, stream);
|
|
else
|
|
gdb_puts (demangled_name.get (), stream);
|
|
return;
|
|
}
|
|
}
|
|
else if (ptr_value != 0)
|
|
{
|
|
/* Found a non-virtual function: print out the type. */
|
|
gdb_puts ("(", stream);
|
|
c_print_type (type, "", stream, -1, 0, current_language->la_language,
|
|
&type_print_raw_options);
|
|
gdb_puts (") ", stream);
|
|
}
|
|
|
|
/* We didn't find it; print the raw data. */
|
|
if (vbit)
|
|
{
|
|
gdb_printf (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)
|
|
{
|
|
gdb_printf (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)
|
|
{
|
|
return 2 * TYPE_LENGTH (builtin_type (type->arch ())->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 = type->arch ();
|
|
int size = TYPE_LENGTH (builtin_type (gdbarch)->builtin_data_ptr);
|
|
enum bfd_endian byte_order = type_byte_order (type);
|
|
|
|
/* 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).data ();
|
|
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 = self_type->arch ();
|
|
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;
|
|
};
|
|
|
|
/* 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));
|
|
}
|
|
|
|
/* Comparison function for value_and_voffset. */
|
|
|
|
static bool
|
|
compare_value_and_voffset (const struct value_and_voffset *va,
|
|
const struct value_and_voffset *vb)
|
|
{
|
|
CORE_ADDR addra = (value_address (va->value)
|
|
+ value_embedded_offset (va->value));
|
|
CORE_ADDR addrb = (value_address (vb->value)
|
|
+ value_embedded_offset (vb->value));
|
|
|
|
return addra < addrb;
|
|
}
|
|
|
|
/* 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,
|
|
std::vector<value_and_voffset *> *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_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;
|
|
offset_vec->push_back (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));
|
|
|
|
gdb_printf (_("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;
|
|
|
|
gdb_printf ("[%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 (const gdb_exception_error &ex)
|
|
{
|
|
fprintf_styled (gdb_stdout, metadata_style.style (),
|
|
_("<error: %s>"), ex.what ());
|
|
got_error = 1;
|
|
}
|
|
|
|
if (!got_error)
|
|
print_function_pointer_address (opts, gdbarch, addr, gdb_stdout);
|
|
gdb_printf ("\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;
|
|
int count;
|
|
|
|
value = coerce_ref (value);
|
|
type = check_typedef (value_type (value));
|
|
if (type->code () == 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 = type->arch ();
|
|
|
|
vtable = NULL;
|
|
if (type->code () == TYPE_CODE_STRUCT)
|
|
vtable = gnuv3_get_vtable (gdbarch, type,
|
|
value_as_address (value_addr (value)));
|
|
|
|
if (!vtable)
|
|
{
|
|
gdb_printf (_("This object does not have a virtual function table\n"));
|
|
return;
|
|
}
|
|
|
|
htab_up offset_hash (htab_create_alloc (1, hash_value_and_voffset,
|
|
eq_value_and_voffset,
|
|
xfree, xcalloc, xfree));
|
|
std::vector<value_and_voffset *> result_vec;
|
|
|
|
compute_vtable_size (offset_hash.get (), &result_vec, value);
|
|
std::sort (result_vec.begin (), result_vec.end (),
|
|
compare_value_and_voffset);
|
|
|
|
count = 0;
|
|
for (value_and_voffset *iter : result_vec)
|
|
{
|
|
if (iter->max_voffset >= 0)
|
|
{
|
|
if (count > 0)
|
|
gdb_printf ("\n");
|
|
print_one_vtable (gdbarch, iter->value, iter->max_voffset, &opts);
|
|
++count;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* 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->set_name ("_vptr.type_info");
|
|
field->set_type (void_ptr_type);
|
|
field->set_loc_bitpos (offset * TARGET_CHAR_BIT);
|
|
offset += TYPE_LENGTH (field->type ());
|
|
field++;
|
|
|
|
/* The name. */
|
|
field->set_name ("__name");
|
|
field->set_type (char_ptr_type);
|
|
field->set_loc_bitpos (offset * TARGET_CHAR_BIT);
|
|
offset += TYPE_LENGTH (field->type ());
|
|
field++;
|
|
|
|
gdb_assert (field == (field_list + 2));
|
|
|
|
t = arch_type (arch, TYPE_CODE_STRUCT, offset * TARGET_CHAR_BIT, NULL);
|
|
t->set_num_fields (field - field_list);
|
|
t->set_fields (field_list);
|
|
t->set_name ("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 = typeinfo->type ();
|
|
|
|
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 value *result;
|
|
std::string type_name;
|
|
gdb::unique_xmalloc_ptr<char> 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_CODE_REF)
|
|
type = check_typedef (TYPE_TARGET_TYPE (type));
|
|
|
|
/* Ignore top-level cv-qualifiers. */
|
|
type = make_cv_type (0, 0, type, NULL);
|
|
gdbarch = type->arch ();
|
|
|
|
type_name = type_to_string (type);
|
|
if (type_name.empty ())
|
|
error (_("cannot find typeinfo for unnamed type"));
|
|
|
|
/* 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.c_str ());
|
|
const char *name = (canonical == nullptr
|
|
? type_name.c_str ()
|
|
: canonical.get ());
|
|
|
|
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_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'"),
|
|
name);
|
|
typeinfo_value = value_field (vtable, vtable_field_type_info);
|
|
result = value_ind (value_cast (make_pointer_type (typeinfo_type, NULL),
|
|
typeinfo_value));
|
|
}
|
|
else
|
|
{
|
|
std::string sym_name = std::string ("typeinfo for ") + name;
|
|
bound_minimal_symbol minsym
|
|
= lookup_minimal_symbol (sym_name.c_str (), NULL, NULL);
|
|
|
|
if (minsym.minsym == NULL)
|
|
error (_("could not find typeinfo symbol for '%s'"), name);
|
|
|
|
result = value_at_lazy (typeinfo_type, minsym.value_address ());
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
/* Implement the 'get_typename_from_type_info' method. */
|
|
|
|
static std::string
|
|
gnuv3_get_typename_from_type_info (struct value *type_info_ptr)
|
|
{
|
|
struct gdbarch *gdbarch = value_type (type_info_ptr)->arch ();
|
|
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 = typeinfo_sym.minsym->demangled_name ();
|
|
if (symname == NULL || strncmp (symname, TYPEINFO_PREFIX,
|
|
TYPEINFO_PREFIX_LEN))
|
|
error (_("typeinfo symbol '%s' has unexpected name"),
|
|
typeinfo_sym.minsym->linkage_name ());
|
|
class_name = symname + TYPEINFO_PREFIX_LEN;
|
|
|
|
/* Strip off @plt and version suffixes. */
|
|
atsign = strchr (class_name, '@');
|
|
if (atsign != NULL)
|
|
return std::string (class_name, atsign - class_name);
|
|
return class_name;
|
|
}
|
|
|
|
/* Implement the 'get_type_from_type_info' method. */
|
|
|
|
static struct type *
|
|
gnuv3_get_type_from_type_info (struct value *type_info_ptr)
|
|
{
|
|
/* 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. */
|
|
std::string type_name = gnuv3_get_typename_from_type_info (type_info_ptr);
|
|
expression_up expr (parse_expression (type_name.c_str ()));
|
|
struct value *type_val = evaluate_type (expr.get ());
|
|
return value_type (type_val);
|
|
}
|
|
|
|
/* 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 = thunk_sym.minsym->demangled_name ();
|
|
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 = fn_sym.value_address ();
|
|
|
|
/* 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, current_inferior ()->top_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;
|
|
}
|
|
|
|
/* A member function is in one these states. */
|
|
|
|
enum definition_style
|
|
{
|
|
DOES_NOT_EXIST_IN_SOURCE,
|
|
DEFAULTED_INSIDE,
|
|
DEFAULTED_OUTSIDE,
|
|
DELETED,
|
|
EXPLICIT,
|
|
};
|
|
|
|
/* Return how the given field is defined. */
|
|
|
|
static definition_style
|
|
get_def_style (struct fn_field *fn, int fieldelem)
|
|
{
|
|
if (TYPE_FN_FIELD_DELETED (fn, fieldelem))
|
|
return DELETED;
|
|
|
|
if (TYPE_FN_FIELD_ARTIFICIAL (fn, fieldelem))
|
|
return DOES_NOT_EXIST_IN_SOURCE;
|
|
|
|
switch (TYPE_FN_FIELD_DEFAULTED (fn, fieldelem))
|
|
{
|
|
case DW_DEFAULTED_no:
|
|
return EXPLICIT;
|
|
case DW_DEFAULTED_in_class:
|
|
return DEFAULTED_INSIDE;
|
|
case DW_DEFAULTED_out_of_class:
|
|
return DEFAULTED_OUTSIDE;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
return EXPLICIT;
|
|
}
|
|
|
|
/* Helper functions to determine whether the given definition style
|
|
denotes that the definition is user-provided or implicit.
|
|
Being defaulted outside the class decl counts as an explicit
|
|
user-definition, while being defaulted inside is implicit. */
|
|
|
|
static bool
|
|
is_user_provided_def (definition_style def)
|
|
{
|
|
return def == EXPLICIT || def == DEFAULTED_OUTSIDE;
|
|
}
|
|
|
|
static bool
|
|
is_implicit_def (definition_style def)
|
|
{
|
|
return def == DOES_NOT_EXIST_IN_SOURCE || def == DEFAULTED_INSIDE;
|
|
}
|
|
|
|
/* Helper function to decide if METHOD_TYPE is a copy/move
|
|
constructor type for CLASS_TYPE. EXPECTED is the expected
|
|
type code for the "right-hand-side" argument.
|
|
This function is supposed to be used by the IS_COPY_CONSTRUCTOR_TYPE
|
|
and IS_MOVE_CONSTRUCTOR_TYPE functions below. Normally, you should
|
|
not need to call this directly. */
|
|
|
|
static bool
|
|
is_copy_or_move_constructor_type (struct type *class_type,
|
|
struct type *method_type,
|
|
type_code expected)
|
|
{
|
|
/* The method should take at least two arguments... */
|
|
if (method_type->num_fields () < 2)
|
|
return false;
|
|
|
|
/* ...and the second argument should be the same as the class
|
|
type, with the expected type code... */
|
|
struct type *arg_type = method_type->field (1).type ();
|
|
|
|
if (arg_type->code () != expected)
|
|
return false;
|
|
|
|
struct type *target = check_typedef (TYPE_TARGET_TYPE (arg_type));
|
|
if (!(class_types_same_p (target, class_type)))
|
|
return false;
|
|
|
|
/* ...and if any of the remaining arguments don't have a default value
|
|
then this is not a copy or move constructor, but just a
|
|
constructor. */
|
|
for (int i = 2; i < method_type->num_fields (); i++)
|
|
{
|
|
arg_type = method_type->field (i).type ();
|
|
/* FIXME aktemur/2019-10-31: As of this date, neither
|
|
clang++-7.0.0 nor g++-8.2.0 produce a DW_AT_default_value
|
|
attribute. GDB is also not set to read this attribute, yet.
|
|
Hence, we immediately return false if there are more than
|
|
2 parameters.
|
|
GCC bug link:
|
|
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42959
|
|
*/
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/* Return true if METHOD_TYPE is a copy ctor type for CLASS_TYPE. */
|
|
|
|
static bool
|
|
is_copy_constructor_type (struct type *class_type,
|
|
struct type *method_type)
|
|
{
|
|
return is_copy_or_move_constructor_type (class_type, method_type,
|
|
TYPE_CODE_REF);
|
|
}
|
|
|
|
/* Return true if METHOD_TYPE is a move ctor type for CLASS_TYPE. */
|
|
|
|
static bool
|
|
is_move_constructor_type (struct type *class_type,
|
|
struct type *method_type)
|
|
{
|
|
return is_copy_or_move_constructor_type (class_type, method_type,
|
|
TYPE_CODE_RVALUE_REF);
|
|
}
|
|
|
|
/* Return pass-by-reference information for the given TYPE.
|
|
|
|
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/move 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 DWARF5 debug
|
|
information, we can check the calling_convention attribute,
|
|
the 'artificial' flag, the 'defaulted' attribute, and the
|
|
'deleted' attribute. */
|
|
|
|
static struct language_pass_by_ref_info
|
|
gnuv3_pass_by_reference (struct type *type)
|
|
{
|
|
int fieldnum, fieldelem;
|
|
|
|
type = check_typedef (type);
|
|
|
|
/* Start with the default values. */
|
|
struct language_pass_by_ref_info info;
|
|
|
|
bool has_cc_attr = false;
|
|
bool is_pass_by_value = false;
|
|
bool is_dynamic = false;
|
|
definition_style cctor_def = DOES_NOT_EXIST_IN_SOURCE;
|
|
definition_style dtor_def = DOES_NOT_EXIST_IN_SOURCE;
|
|
definition_style mctor_def = DOES_NOT_EXIST_IN_SOURCE;
|
|
|
|
/* We're only interested in things that can have methods. */
|
|
if (type->code () != TYPE_CODE_STRUCT
|
|
&& type->code () != TYPE_CODE_UNION)
|
|
return info;
|
|
|
|
/* The compiler may have emitted the calling convention attribute.
|
|
Note: GCC does not produce this attribute as of version 9.2.1.
|
|
Bug link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92418 */
|
|
if (TYPE_CPLUS_CALLING_CONVENTION (type) == DW_CC_pass_by_value)
|
|
{
|
|
has_cc_attr = true;
|
|
is_pass_by_value = true;
|
|
/* Do not return immediately. We have to find out if this type
|
|
is copy_constructible and destructible. */
|
|
}
|
|
|
|
if (TYPE_CPLUS_CALLING_CONVENTION (type) == DW_CC_pass_by_reference)
|
|
{
|
|
has_cc_attr = true;
|
|
is_pass_by_value = false;
|
|
}
|
|
|
|
/* 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))
|
|
is_dynamic = true;
|
|
|
|
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 (name[0] == '~')
|
|
{
|
|
/* We've found a destructor.
|
|
There should be at most one dtor definition. */
|
|
gdb_assert (dtor_def == DOES_NOT_EXIST_IN_SOURCE);
|
|
dtor_def = get_def_style (fn, fieldelem);
|
|
}
|
|
else if (is_constructor_name (TYPE_FN_FIELD_PHYSNAME (fn, fieldelem))
|
|
|| TYPE_FN_FIELD_CONSTRUCTOR (fn, fieldelem))
|
|
{
|
|
/* 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_copy_constructor_type (type, fieldtype))
|
|
{
|
|
/* There may be more than one cctors. E.g.: one that
|
|
take a const parameter and another that takes a
|
|
non-const parameter. Such as:
|
|
|
|
class K {
|
|
K (const K &k)...
|
|
K (K &k)...
|
|
};
|
|
|
|
It is sufficient for the type to be non-trivial
|
|
even only one of the cctors is explicit.
|
|
Therefore, update the cctor_def value in the
|
|
implicit -> explicit direction, not backwards. */
|
|
|
|
if (is_implicit_def (cctor_def))
|
|
cctor_def = get_def_style (fn, fieldelem);
|
|
}
|
|
else if (is_move_constructor_type (type, fieldtype))
|
|
{
|
|
/* Again, there may be multiple move ctors. Update the
|
|
mctor_def value if we found an explicit def and the
|
|
existing one is not explicit. Otherwise retain the
|
|
existing value. */
|
|
if (is_implicit_def (mctor_def))
|
|
mctor_def = get_def_style (fn, fieldelem);
|
|
}
|
|
}
|
|
}
|
|
|
|
bool cctor_implicitly_deleted
|
|
= (mctor_def != DOES_NOT_EXIST_IN_SOURCE
|
|
&& cctor_def == DOES_NOT_EXIST_IN_SOURCE);
|
|
|
|
bool cctor_explicitly_deleted = (cctor_def == DELETED);
|
|
|
|
if (cctor_implicitly_deleted || cctor_explicitly_deleted)
|
|
info.copy_constructible = false;
|
|
|
|
if (dtor_def == DELETED)
|
|
info.destructible = false;
|
|
|
|
info.trivially_destructible = is_implicit_def (dtor_def);
|
|
|
|
info.trivially_copy_constructible
|
|
= (is_implicit_def (cctor_def)
|
|
&& !is_dynamic);
|
|
|
|
info.trivially_copyable
|
|
= (info.trivially_copy_constructible
|
|
&& info.trivially_destructible
|
|
&& !is_user_provided_def (mctor_def));
|
|
|
|
/* 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->num_fields (); fieldnum++)
|
|
if (!field_is_static (&type->field (fieldnum)))
|
|
{
|
|
struct type *field_type = type->field (fieldnum).type ();
|
|
|
|
/* For arrays, make the decision based on the element type. */
|
|
if (field_type->code () == TYPE_CODE_ARRAY)
|
|
field_type = check_typedef (TYPE_TARGET_TYPE (field_type));
|
|
|
|
struct language_pass_by_ref_info field_info
|
|
= gnuv3_pass_by_reference (field_type);
|
|
|
|
if (!field_info.copy_constructible)
|
|
info.copy_constructible = false;
|
|
if (!field_info.destructible)
|
|
info.destructible = false;
|
|
if (!field_info.trivially_copyable)
|
|
info.trivially_copyable = false;
|
|
if (!field_info.trivially_copy_constructible)
|
|
info.trivially_copy_constructible = false;
|
|
if (!field_info.trivially_destructible)
|
|
info.trivially_destructible = false;
|
|
}
|
|
|
|
/* Consistency check. */
|
|
if (has_cc_attr && info.trivially_copyable != is_pass_by_value)
|
|
{
|
|
/* DWARF CC attribute is not the same as the inferred value;
|
|
use the DWARF attribute. */
|
|
info.trivially_copyable = is_pass_by_value;
|
|
}
|
|
|
|
return info;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
void _initialize_gnu_v3_abi ();
|
|
void
|
|
_initialize_gnu_v3_abi ()
|
|
{
|
|
init_gnuv3_ops ();
|
|
|
|
register_cp_abi (&gnu_v3_abi_ops);
|
|
set_cp_abi_as_auto_default (gnu_v3_abi_ops.shortname);
|
|
}
|