| /* Abstraction of GNU v3 abi. |
| Contributed by Jim Blandy <jimb@redhat.com> |
| |
| Copyright (C) 2001-2003, 2005-2012 Free Software Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| #include "defs.h" |
| #include "value.h" |
| #include "cp-abi.h" |
| #include "cp-support.h" |
| #include "demangle.h" |
| #include "objfiles.h" |
| #include "valprint.h" |
| #include "c-lang.h" |
| #include "exceptions.h" |
| |
| #include "gdb_assert.h" |
| #include "gdb_string.h" |
| |
| static struct cp_abi_ops gnu_v3_abi_ops; |
| |
| static int |
| gnuv3_is_vtable_name (const char *name) |
| { |
| return strncmp (name, "_ZTV", 4) == 0; |
| } |
| |
| static int |
| gnuv3_is_operator_name (const char *name) |
| { |
| return strncmp (name, "operator", 8) == 0; |
| } |
| |
| |
| /* To help us find the components of a vtable, we build ourselves a |
| GDB type object representing the vtable structure. Following the |
| V3 ABI, it goes something like this: |
| |
| struct gdb_gnu_v3_abi_vtable { |
| |
| / * An array of virtual call and virtual base offsets. The real |
| length of this array depends on the class hierarchy; we use |
| negative subscripts to access the elements. Yucky, but |
| better than the alternatives. * / |
| ptrdiff_t vcall_and_vbase_offsets[0]; |
| |
| / * The offset from a virtual pointer referring to this table |
| to the top of the complete object. * / |
| ptrdiff_t offset_to_top; |
| |
| / * The type_info pointer for this class. This is really a |
| std::type_info *, but GDB doesn't really look at the |
| type_info object itself, so we don't bother to get the type |
| exactly right. * / |
| void *type_info; |
| |
| / * Virtual table pointers in objects point here. * / |
| |
| / * Virtual function pointers. Like the vcall/vbase array, the |
| real length of this table depends on the class hierarchy. * / |
| void (*virtual_functions[0]) (); |
| |
| }; |
| |
| The catch, of course, is that the exact layout of this table |
| depends on the ABI --- word size, endianness, alignment, etc. So |
| the GDB type object is actually a per-architecture kind of thing. |
| |
| vtable_type_gdbarch_data is a gdbarch per-architecture data pointer |
| which refers to the struct type * for this structure, laid out |
| appropriately for the architecture. */ |
| static struct gdbarch_data *vtable_type_gdbarch_data; |
| |
| |
| /* Human-readable names for the numbers of the fields above. */ |
| enum { |
| vtable_field_vcall_and_vbase_offsets, |
| vtable_field_offset_to_top, |
| vtable_field_type_info, |
| vtable_field_virtual_functions |
| }; |
| |
| |
| /* Return a GDB type representing `struct gdb_gnu_v3_abi_vtable', |
| described above, laid out appropriately for ARCH. |
| |
| We use this function as the gdbarch per-architecture data |
| initialization function. */ |
| static void * |
| build_gdb_vtable_type (struct gdbarch *arch) |
| { |
| struct type *t; |
| struct field *field_list, *field; |
| int offset; |
| |
| struct type *void_ptr_type |
| = builtin_type (arch)->builtin_data_ptr; |
| struct type *ptr_to_void_fn_type |
| = builtin_type (arch)->builtin_func_ptr; |
| |
| /* ARCH can't give us the true ptrdiff_t type, so we guess. */ |
| struct type *ptrdiff_type |
| = arch_integer_type (arch, gdbarch_ptr_bit (arch), 0, "ptrdiff_t"); |
| |
| /* We assume no padding is necessary, since GDB doesn't know |
| anything about alignment at the moment. If this assumption bites |
| us, we should add a gdbarch method which, given a type, returns |
| the alignment that type requires, and then use that here. */ |
| |
| /* Build the field list. */ |
| field_list = xmalloc (sizeof (struct field [4])); |
| memset (field_list, 0, sizeof (struct field [4])); |
| field = &field_list[0]; |
| offset = 0; |
| |
| /* ptrdiff_t vcall_and_vbase_offsets[0]; */ |
| FIELD_NAME (*field) = "vcall_and_vbase_offsets"; |
| FIELD_TYPE (*field) = lookup_array_range_type (ptrdiff_type, 0, -1); |
| SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT); |
| offset += TYPE_LENGTH (FIELD_TYPE (*field)); |
| field++; |
| |
| /* ptrdiff_t offset_to_top; */ |
| FIELD_NAME (*field) = "offset_to_top"; |
| FIELD_TYPE (*field) = ptrdiff_type; |
| SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT); |
| offset += TYPE_LENGTH (FIELD_TYPE (*field)); |
| field++; |
| |
| /* void *type_info; */ |
| FIELD_NAME (*field) = "type_info"; |
| FIELD_TYPE (*field) = void_ptr_type; |
| SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT); |
| offset += TYPE_LENGTH (FIELD_TYPE (*field)); |
| field++; |
| |
| /* void (*virtual_functions[0]) (); */ |
| FIELD_NAME (*field) = "virtual_functions"; |
| FIELD_TYPE (*field) = lookup_array_range_type (ptr_to_void_fn_type, 0, -1); |
| SET_FIELD_BITPOS (*field, offset * TARGET_CHAR_BIT); |
| offset += TYPE_LENGTH (FIELD_TYPE (*field)); |
| field++; |
| |
| /* We assumed in the allocation above that there were four fields. */ |
| gdb_assert (field == (field_list + 4)); |
| |
| t = arch_type (arch, TYPE_CODE_STRUCT, offset, NULL); |
| TYPE_NFIELDS (t) = field - field_list; |
| TYPE_FIELDS (t) = field_list; |
| TYPE_TAG_NAME (t) = "gdb_gnu_v3_abi_vtable"; |
| INIT_CPLUS_SPECIFIC (t); |
| |
| return t; |
| } |
| |
| |
| /* Return the ptrdiff_t type used in the vtable type. */ |
| static struct type * |
| vtable_ptrdiff_type (struct gdbarch *gdbarch) |
| { |
| struct type *vtable_type = gdbarch_data (gdbarch, vtable_type_gdbarch_data); |
| |
| /* The "offset_to_top" field has the appropriate (ptrdiff_t) type. */ |
| return TYPE_FIELD_TYPE (vtable_type, vtable_field_offset_to_top); |
| } |
| |
| /* Return the offset from the start of the imaginary `struct |
| gdb_gnu_v3_abi_vtable' object to the vtable's "address point" |
| (i.e., where objects' virtual table pointers point). */ |
| static int |
| vtable_address_point_offset (struct gdbarch *gdbarch) |
| { |
| struct type *vtable_type = gdbarch_data (gdbarch, vtable_type_gdbarch_data); |
| |
| return (TYPE_FIELD_BITPOS (vtable_type, vtable_field_virtual_functions) |
| / TARGET_CHAR_BIT); |
| } |
| |
| |
| /* Determine whether structure TYPE is a dynamic class. Cache the |
| result. */ |
| |
| static int |
| gnuv3_dynamic_class (struct type *type) |
| { |
| int fieldnum, fieldelem; |
| |
| if (TYPE_CPLUS_DYNAMIC (type)) |
| return TYPE_CPLUS_DYNAMIC (type) == 1; |
| |
| ALLOCATE_CPLUS_STRUCT_TYPE (type); |
| |
| for (fieldnum = 0; fieldnum < TYPE_N_BASECLASSES (type); fieldnum++) |
| if (BASETYPE_VIA_VIRTUAL (type, fieldnum) |
| || gnuv3_dynamic_class (TYPE_FIELD_TYPE (type, fieldnum))) |
| { |
| TYPE_CPLUS_DYNAMIC (type) = 1; |
| return 1; |
| } |
| |
| for (fieldnum = 0; fieldnum < TYPE_NFN_FIELDS (type); fieldnum++) |
| for (fieldelem = 0; fieldelem < TYPE_FN_FIELDLIST_LENGTH (type, fieldnum); |
| fieldelem++) |
| { |
| struct fn_field *f = TYPE_FN_FIELDLIST1 (type, fieldnum); |
| |
| if (TYPE_FN_FIELD_VIRTUAL_P (f, fieldelem)) |
| { |
| TYPE_CPLUS_DYNAMIC (type) = 1; |
| return 1; |
| } |
| } |
| |
| TYPE_CPLUS_DYNAMIC (type) = -1; |
| return 0; |
| } |
| |
| /* Find the vtable for a value of CONTAINER_TYPE located at |
| CONTAINER_ADDR. Return a value of the correct vtable type for this |
| architecture, or NULL if CONTAINER does not have a vtable. */ |
| |
| static struct value * |
| gnuv3_get_vtable (struct gdbarch *gdbarch, |
| struct type *container_type, CORE_ADDR container_addr) |
| { |
| struct type *vtable_type = gdbarch_data (gdbarch, |
| vtable_type_gdbarch_data); |
| struct type *vtable_pointer_type; |
| struct value *vtable_pointer; |
| CORE_ADDR vtable_address; |
| |
| /* If this type does not have a virtual table, don't read the first |
| field. */ |
| if (!gnuv3_dynamic_class (check_typedef (container_type))) |
| return NULL; |
| |
| /* We do not consult the debug information to find the virtual table. |
| The ABI specifies that it is always at offset zero in any class, |
| and debug information may not represent it. |
| |
| We avoid using value_contents on principle, because the object might |
| be large. */ |
| |
| /* Find the type "pointer to virtual table". */ |
| vtable_pointer_type = lookup_pointer_type (vtable_type); |
| |
| /* Load it from the start of the class. */ |
| vtable_pointer = value_at (vtable_pointer_type, container_addr); |
| vtable_address = value_as_address (vtable_pointer); |
| |
| /* Correct it to point at the start of the virtual table, rather |
| than the address point. */ |
| return value_at_lazy (vtable_type, |
| vtable_address |
| - vtable_address_point_offset (gdbarch)); |
| } |
| |
| |
| static struct type * |
| gnuv3_rtti_type (struct value *value, |
| int *full_p, int *top_p, int *using_enc_p) |
| { |
| struct gdbarch *gdbarch; |
| struct type *values_type = check_typedef (value_type (value)); |
| struct value *vtable; |
| struct minimal_symbol *vtable_symbol; |
| const char *vtable_symbol_name; |
| const char *class_name; |
| struct type *run_time_type; |
| LONGEST offset_to_top; |
| |
| /* We only have RTTI for class objects. */ |
| if (TYPE_CODE (values_type) != TYPE_CODE_CLASS) |
| return NULL; |
| |
| /* Java doesn't have RTTI following the C++ ABI. */ |
| if (TYPE_CPLUS_REALLY_JAVA (values_type)) |
| return NULL; |
| |
| /* Determine architecture. */ |
| gdbarch = get_type_arch (values_type); |
| |
| if (using_enc_p) |
| *using_enc_p = 0; |
| |
| vtable = gnuv3_get_vtable (gdbarch, value_type (value), |
| value_as_address (value_addr (value))); |
| if (vtable == NULL) |
| return NULL; |
| |
| /* Find the linker symbol for this vtable. */ |
| vtable_symbol |
| = lookup_minimal_symbol_by_pc (value_address (vtable) |
| + value_embedded_offset (vtable)); |
| if (! vtable_symbol) |
| return NULL; |
| |
| /* The symbol's demangled name should be something like "vtable for |
| CLASS", where CLASS is the name of the run-time type of VALUE. |
| If we didn't like this approach, we could instead look in the |
| type_info object itself to get the class name. But this way |
| should work just as well, and doesn't read target memory. */ |
| vtable_symbol_name = SYMBOL_DEMANGLED_NAME (vtable_symbol); |
| if (vtable_symbol_name == NULL |
| || strncmp (vtable_symbol_name, "vtable for ", 11)) |
| { |
| warning (_("can't find linker symbol for virtual table for `%s' value"), |
| TYPE_SAFE_NAME (values_type)); |
| if (vtable_symbol_name) |
| warning (_(" found `%s' instead"), vtable_symbol_name); |
| return NULL; |
| } |
| class_name = vtable_symbol_name + 11; |
| |
| /* Try to look up the class name as a type name. */ |
| /* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */ |
| run_time_type = cp_lookup_rtti_type (class_name, NULL); |
| if (run_time_type == NULL) |
| return NULL; |
| |
| /* Get the offset from VALUE to the top of the complete object. |
| NOTE: this is the reverse of the meaning of *TOP_P. */ |
| offset_to_top |
| = value_as_long (value_field (vtable, vtable_field_offset_to_top)); |
| |
| if (full_p) |
| *full_p = (- offset_to_top == value_embedded_offset (value) |
| && (TYPE_LENGTH (value_enclosing_type (value)) |
| >= TYPE_LENGTH (run_time_type))); |
| if (top_p) |
| *top_p = - offset_to_top; |
| return run_time_type; |
| } |
| |
| /* Return a function pointer for CONTAINER's VTABLE_INDEX'th virtual |
| function, of type FNTYPE. */ |
| |
| static struct value * |
| gnuv3_get_virtual_fn (struct gdbarch *gdbarch, struct value *container, |
| struct type *fntype, int vtable_index) |
| { |
| struct value *vtable, *vfn; |
| |
| /* Every class with virtual functions must have a vtable. */ |
| vtable = gnuv3_get_vtable (gdbarch, value_type (container), |
| value_as_address (value_addr (container))); |
| gdb_assert (vtable != NULL); |
| |
| /* Fetch the appropriate function pointer from the vtable. */ |
| vfn = value_subscript (value_field (vtable, vtable_field_virtual_functions), |
| vtable_index); |
| |
| /* If this architecture uses function descriptors directly in the vtable, |
| then the address of the vtable entry is actually a "function pointer" |
| (i.e. points to the descriptor). We don't need to scale the index |
| by the size of a function descriptor; GCC does that before outputing |
| debug information. */ |
| if (gdbarch_vtable_function_descriptors (gdbarch)) |
| vfn = value_addr (vfn); |
| |
| /* Cast the function pointer to the appropriate type. */ |
| vfn = value_cast (lookup_pointer_type (fntype), vfn); |
| |
| return vfn; |
| } |
| |
| /* GNU v3 implementation of value_virtual_fn_field. See cp-abi.h |
| for a description of the arguments. */ |
| |
| static struct value * |
| gnuv3_virtual_fn_field (struct value **value_p, |
| struct fn_field *f, int j, |
| struct type *vfn_base, int offset) |
| { |
| struct type *values_type = check_typedef (value_type (*value_p)); |
| struct gdbarch *gdbarch; |
| |
| /* Some simple sanity checks. */ |
| if (TYPE_CODE (values_type) != TYPE_CODE_CLASS) |
| error (_("Only classes can have virtual functions.")); |
| |
| /* Determine architecture. */ |
| gdbarch = get_type_arch (values_type); |
| |
| /* Cast our value to the base class which defines this virtual |
| function. This takes care of any necessary `this' |
| adjustments. */ |
| if (vfn_base != values_type) |
| *value_p = value_cast (vfn_base, *value_p); |
| |
| return gnuv3_get_virtual_fn (gdbarch, *value_p, TYPE_FN_FIELD_TYPE (f, j), |
| TYPE_FN_FIELD_VOFFSET (f, j)); |
| } |
| |
| /* Compute the offset of the baseclass which is |
| the INDEXth baseclass of class TYPE, |
| for value at VALADDR (in host) at ADDRESS (in target). |
| The result is the offset of the baseclass value relative |
| to (the address of)(ARG) + OFFSET. |
| |
| -1 is returned on error. */ |
| |
| static int |
| gnuv3_baseclass_offset (struct type *type, int index, |
| const bfd_byte *valaddr, int embedded_offset, |
| CORE_ADDR address, const struct value *val) |
| { |
| struct gdbarch *gdbarch; |
| struct type *ptr_type; |
| struct value *vtable; |
| struct value *vbase_array; |
| long int cur_base_offset, base_offset; |
| |
| /* Determine architecture. */ |
| gdbarch = get_type_arch (type); |
| ptr_type = builtin_type (gdbarch)->builtin_data_ptr; |
| |
| /* If it isn't a virtual base, this is easy. The offset is in the |
| type definition. Likewise for Java, which doesn't really have |
| virtual inheritance in the C++ sense. */ |
| if (!BASETYPE_VIA_VIRTUAL (type, index) || TYPE_CPLUS_REALLY_JAVA (type)) |
| return TYPE_BASECLASS_BITPOS (type, index) / 8; |
| |
| /* To access a virtual base, we need to use the vbase offset stored in |
| our vtable. Recent GCC versions provide this information. If it isn't |
| available, we could get what we needed from RTTI, or from drawing the |
| complete inheritance graph based on the debug info. Neither is |
| worthwhile. */ |
| cur_base_offset = TYPE_BASECLASS_BITPOS (type, index) / 8; |
| if (cur_base_offset >= - vtable_address_point_offset (gdbarch)) |
| error (_("Expected a negative vbase offset (old compiler?)")); |
| |
| cur_base_offset = cur_base_offset + vtable_address_point_offset (gdbarch); |
| if ((- cur_base_offset) % TYPE_LENGTH (ptr_type) != 0) |
| error (_("Misaligned vbase offset.")); |
| cur_base_offset = cur_base_offset / ((int) TYPE_LENGTH (ptr_type)); |
| |
| vtable = gnuv3_get_vtable (gdbarch, type, address + embedded_offset); |
| gdb_assert (vtable != NULL); |
| vbase_array = value_field (vtable, vtable_field_vcall_and_vbase_offsets); |
| base_offset = value_as_long (value_subscript (vbase_array, cur_base_offset)); |
| return base_offset; |
| } |
| |
| /* Locate a virtual method in DOMAIN or its non-virtual base classes |
| which has virtual table index VOFFSET. The method has an associated |
| "this" adjustment of ADJUSTMENT bytes. */ |
| |
| static const char * |
| gnuv3_find_method_in (struct type *domain, CORE_ADDR voffset, |
| LONGEST adjustment) |
| { |
| int i; |
| |
| /* Search this class first. */ |
| if (adjustment == 0) |
| { |
| int len; |
| |
| len = TYPE_NFN_FIELDS (domain); |
| for (i = 0; i < len; i++) |
| { |
| int len2, j; |
| struct fn_field *f; |
| |
| f = TYPE_FN_FIELDLIST1 (domain, i); |
| len2 = TYPE_FN_FIELDLIST_LENGTH (domain, i); |
| |
| check_stub_method_group (domain, i); |
| for (j = 0; j < len2; j++) |
| if (TYPE_FN_FIELD_VOFFSET (f, j) == voffset) |
| return TYPE_FN_FIELD_PHYSNAME (f, j); |
| } |
| } |
| |
| /* Next search non-virtual bases. If it's in a virtual base, |
| we're out of luck. */ |
| for (i = 0; i < TYPE_N_BASECLASSES (domain); i++) |
| { |
| int pos; |
| struct type *basetype; |
| |
| if (BASETYPE_VIA_VIRTUAL (domain, i)) |
| continue; |
| |
| pos = TYPE_BASECLASS_BITPOS (domain, i) / 8; |
| basetype = TYPE_FIELD_TYPE (domain, i); |
| /* Recurse with a modified adjustment. We don't need to adjust |
| voffset. */ |
| if (adjustment >= pos && adjustment < pos + TYPE_LENGTH (basetype)) |
| return gnuv3_find_method_in (basetype, voffset, adjustment - pos); |
| } |
| |
| return NULL; |
| } |
| |
| /* Decode GNU v3 method pointer. */ |
| |
| static int |
| gnuv3_decode_method_ptr (struct gdbarch *gdbarch, |
| const gdb_byte *contents, |
| CORE_ADDR *value_p, |
| LONGEST *adjustment_p) |
| { |
| struct type *funcptr_type = builtin_type (gdbarch)->builtin_func_ptr; |
| struct type *offset_type = vtable_ptrdiff_type (gdbarch); |
| enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| CORE_ADDR ptr_value; |
| LONGEST voffset, adjustment; |
| int vbit; |
| |
| /* Extract the pointer to member. The first element is either a pointer |
| or a vtable offset. For pointers, we need to use extract_typed_address |
| to allow the back-end to convert the pointer to a GDB address -- but |
| vtable offsets we must handle as integers. At this point, we do not |
| yet know which case we have, so we extract the value under both |
| interpretations and choose the right one later on. */ |
| ptr_value = extract_typed_address (contents, funcptr_type); |
| voffset = extract_signed_integer (contents, |
| TYPE_LENGTH (funcptr_type), byte_order); |
| contents += TYPE_LENGTH (funcptr_type); |
| adjustment = extract_signed_integer (contents, |
| TYPE_LENGTH (offset_type), byte_order); |
| |
| if (!gdbarch_vbit_in_delta (gdbarch)) |
| { |
| vbit = voffset & 1; |
| voffset = voffset ^ vbit; |
| } |
| else |
| { |
| vbit = adjustment & 1; |
| adjustment = adjustment >> 1; |
| } |
| |
| *value_p = vbit? voffset : ptr_value; |
| *adjustment_p = adjustment; |
| return vbit; |
| } |
| |
| /* GNU v3 implementation of cplus_print_method_ptr. */ |
| |
| static void |
| gnuv3_print_method_ptr (const gdb_byte *contents, |
| struct type *type, |
| struct ui_file *stream) |
| { |
| struct type *domain = TYPE_DOMAIN_TYPE (type); |
| struct gdbarch *gdbarch = get_type_arch (domain); |
| CORE_ADDR ptr_value; |
| LONGEST adjustment; |
| int vbit; |
| |
| /* Extract the pointer to member. */ |
| vbit = gnuv3_decode_method_ptr (gdbarch, contents, &ptr_value, &adjustment); |
| |
| /* Check for NULL. */ |
| if (ptr_value == 0 && vbit == 0) |
| { |
| fprintf_filtered (stream, "NULL"); |
| return; |
| } |
| |
| /* Search for a virtual method. */ |
| if (vbit) |
| { |
| CORE_ADDR voffset; |
| const char *physname; |
| |
| /* It's a virtual table offset, maybe in this class. Search |
| for a field with the correct vtable offset. First convert it |
| to an index, as used in TYPE_FN_FIELD_VOFFSET. */ |
| voffset = ptr_value / TYPE_LENGTH (vtable_ptrdiff_type (gdbarch)); |
| |
| physname = gnuv3_find_method_in (domain, voffset, adjustment); |
| |
| /* If we found a method, print that. We don't bother to disambiguate |
| possible paths to the method based on the adjustment. */ |
| if (physname) |
| { |
| char *demangled_name = cplus_demangle (physname, |
| DMGL_ANSI | DMGL_PARAMS); |
| |
| fprintf_filtered (stream, "&virtual "); |
| if (demangled_name == NULL) |
| fputs_filtered (physname, stream); |
| else |
| { |
| fputs_filtered (demangled_name, stream); |
| xfree (demangled_name); |
| } |
| return; |
| } |
| } |
| else if (ptr_value != 0) |
| { |
| /* Found a non-virtual function: print out the type. */ |
| fputs_filtered ("(", stream); |
| c_print_type (type, "", stream, -1, 0); |
| fputs_filtered (") ", stream); |
| } |
| |
| /* We didn't find it; print the raw data. */ |
| if (vbit) |
| { |
| fprintf_filtered (stream, "&virtual table offset "); |
| print_longest (stream, 'd', 1, ptr_value); |
| } |
| else |
| { |
| struct value_print_options opts; |
| |
| get_user_print_options (&opts); |
| print_address_demangle (&opts, gdbarch, ptr_value, stream, demangle); |
| } |
| |
| if (adjustment) |
| { |
| fprintf_filtered (stream, ", this adjustment "); |
| print_longest (stream, 'd', 1, adjustment); |
| } |
| } |
| |
| /* GNU v3 implementation of cplus_method_ptr_size. */ |
| |
| static int |
| gnuv3_method_ptr_size (struct type *type) |
| { |
| struct gdbarch *gdbarch = get_type_arch (type); |
| |
| return 2 * TYPE_LENGTH (builtin_type (gdbarch)->builtin_data_ptr); |
| } |
| |
| /* GNU v3 implementation of cplus_make_method_ptr. */ |
| |
| static void |
| gnuv3_make_method_ptr (struct type *type, gdb_byte *contents, |
| CORE_ADDR value, int is_virtual) |
| { |
| struct gdbarch *gdbarch = get_type_arch (type); |
| int size = TYPE_LENGTH (builtin_type (gdbarch)->builtin_data_ptr); |
| enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| |
| /* FIXME drow/2006-12-24: The adjustment of "this" is currently |
| always zero, since the method pointer is of the correct type. |
| But if the method pointer came from a base class, this is |
| incorrect - it should be the offset to the base. The best |
| fix might be to create the pointer to member pointing at the |
| base class and cast it to the derived class, but that requires |
| support for adjusting pointers to members when casting them - |
| not currently supported by GDB. */ |
| |
| if (!gdbarch_vbit_in_delta (gdbarch)) |
| { |
| store_unsigned_integer (contents, size, byte_order, value | is_virtual); |
| store_unsigned_integer (contents + size, size, byte_order, 0); |
| } |
| else |
| { |
| store_unsigned_integer (contents, size, byte_order, value); |
| store_unsigned_integer (contents + size, size, byte_order, is_virtual); |
| } |
| } |
| |
| /* GNU v3 implementation of cplus_method_ptr_to_value. */ |
| |
| static struct value * |
| gnuv3_method_ptr_to_value (struct value **this_p, struct value *method_ptr) |
| { |
| struct gdbarch *gdbarch; |
| const gdb_byte *contents = value_contents (method_ptr); |
| CORE_ADDR ptr_value; |
| struct type *domain_type, *final_type, *method_type; |
| LONGEST adjustment; |
| int vbit; |
| |
| domain_type = TYPE_DOMAIN_TYPE (check_typedef (value_type (method_ptr))); |
| final_type = lookup_pointer_type (domain_type); |
| |
| method_type = TYPE_TARGET_TYPE (check_typedef (value_type (method_ptr))); |
| |
| /* Extract the pointer to member. */ |
| gdbarch = get_type_arch (domain_type); |
| vbit = gnuv3_decode_method_ptr (gdbarch, contents, &ptr_value, &adjustment); |
| |
| /* First convert THIS to match the containing type of the pointer to |
| member. This cast may adjust the value of THIS. */ |
| *this_p = value_cast (final_type, *this_p); |
| |
| /* Then apply whatever adjustment is necessary. This creates a somewhat |
| strange pointer: it claims to have type FINAL_TYPE, but in fact it |
| might not be a valid FINAL_TYPE. For instance, it might be a |
| base class of FINAL_TYPE. And if it's not the primary base class, |
| then printing it out as a FINAL_TYPE object would produce some pretty |
| garbage. |
| |
| But we don't really know the type of the first argument in |
| METHOD_TYPE either, which is why this happens. We can't |
| dereference this later as a FINAL_TYPE, but once we arrive in the |
| called method we'll have debugging information for the type of |
| "this" - and that'll match the value we produce here. |
| |
| You can provoke this case by casting a Base::* to a Derived::*, for |
| instance. */ |
| *this_p = value_cast (builtin_type (gdbarch)->builtin_data_ptr, *this_p); |
| *this_p = value_ptradd (*this_p, adjustment); |
| *this_p = value_cast (final_type, *this_p); |
| |
| if (vbit) |
| { |
| LONGEST voffset; |
| |
| voffset = ptr_value / TYPE_LENGTH (vtable_ptrdiff_type (gdbarch)); |
| return gnuv3_get_virtual_fn (gdbarch, value_ind (*this_p), |
| method_type, voffset); |
| } |
| else |
| return value_from_pointer (lookup_pointer_type (method_type), ptr_value); |
| } |
| |
| /* Objects of this type are stored in a hash table and a vector when |
| printing the vtables for a class. */ |
| |
| struct value_and_voffset |
| { |
| /* The value representing the object. */ |
| struct value *value; |
| |
| /* The maximum vtable offset we've found for any object at this |
| offset in the outermost object. */ |
| int max_voffset; |
| }; |
| |
| typedef struct value_and_voffset *value_and_voffset_p; |
| DEF_VEC_P (value_and_voffset_p); |
| |
| /* Hash function for value_and_voffset. */ |
| |
| static hashval_t |
| hash_value_and_voffset (const void *p) |
| { |
| const struct value_and_voffset *o = 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 = a; |
| const struct value_and_voffset *ovb = b; |
| |
| return (value_address (ova->value) + value_embedded_offset (ova->value) |
| == value_address (ovb->value) + value_embedded_offset (ovb->value)); |
| } |
| |
| /* qsort comparison function for value_and_voffset. */ |
| |
| static int |
| compare_value_and_voffset (const void *a, const void *b) |
| { |
| const struct value_and_voffset * const *ova = a; |
| CORE_ADDR addra = (value_address ((*ova)->value) |
| + value_embedded_offset ((*ova)->value)); |
| const struct value_and_voffset * const *ovb = b; |
| CORE_ADDR addrb = (value_address ((*ovb)->value) |
| + value_embedded_offset ((*ovb)->value)); |
| |
| if (addra < addrb) |
| return -1; |
| if (addra > addrb) |
| return 1; |
| return 0; |
| } |
| |
| /* A helper function used when printing vtables. This determines the |
| key (most derived) sub-object at each address and also computes the |
| maximum vtable offset seen for the corresponding vtable. Updates |
| OFFSET_HASH and OFFSET_VEC with a new value_and_voffset object, if |
| needed. VALUE is the object to examine. */ |
| |
| static void |
| compute_vtable_size (htab_t offset_hash, |
| VEC (value_and_voffset_p) **offset_vec, |
| struct value *value) |
| { |
| int i; |
| struct type *type = check_typedef (value_type (value)); |
| void **slot; |
| struct value_and_voffset search_vo, *current_vo; |
| CORE_ADDR addr = value_address (value) + value_embedded_offset (value); |
| |
| /* 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 = *slot; |
| else |
| { |
| current_vo = XNEW (struct value_and_voffset); |
| current_vo->value = value; |
| current_vo->max_voffset = -1; |
| *slot = current_vo; |
| VEC_safe_push (value_and_voffset_p, *offset_vec, current_vo); |
| } |
| |
| /* Update the value_and_voffset object with the highest vtable |
| offset from this class. */ |
| for (i = 0; i < TYPE_NFN_FIELDS (type); ++i) |
| { |
| int j; |
| struct fn_field *fn = TYPE_FN_FIELDLIST1 (type, i); |
| |
| for (j = 0; j < TYPE_FN_FIELDLIST_LENGTH (type, i); ++j) |
| { |
| if (TYPE_FN_FIELD_VIRTUAL_P (fn, j)) |
| { |
| int voffset = TYPE_FN_FIELD_VOFFSET (fn, j); |
| |
| if (voffset > current_vo->max_voffset) |
| current_vo->max_voffset = voffset; |
| } |
| } |
| } |
| |
| /* Recurse into base classes. */ |
| for (i = 0; i < TYPE_N_BASECLASSES (type); ++i) |
| compute_vtable_size (offset_hash, offset_vec, value_field (value, i)); |
| } |
| |
| /* Helper for gnuv3_print_vtable that prints a single vtable. */ |
| |
| static void |
| print_one_vtable (struct gdbarch *gdbarch, struct value *value, |
| int max_voffset, |
| struct value_print_options *opts) |
| { |
| int i; |
| struct type *type = check_typedef (value_type (value)); |
| struct value *vtable; |
| CORE_ADDR vt_addr; |
| |
| vtable = gnuv3_get_vtable (gdbarch, type, |
| value_address (value) |
| + value_embedded_offset (value)); |
| vt_addr = value_address (value_field (vtable, |
| vtable_field_virtual_functions)); |
| |
| printf_filtered (_("vtable for '%s' @ %s (subobject @ %s):\n"), |
| TYPE_SAFE_NAME (type), |
| paddress (gdbarch, vt_addr), |
| paddress (gdbarch, (value_address (value) |
| + value_embedded_offset (value)))); |
| |
| for (i = 0; i <= max_voffset; ++i) |
| { |
| /* Initialize it just to avoid a GCC false warning. */ |
| CORE_ADDR addr = 0; |
| struct value *vfn; |
| volatile struct gdb_exception ex; |
| |
| printf_filtered ("[%d]: ", i); |
| |
| vfn = value_subscript (value_field (vtable, |
| vtable_field_virtual_functions), |
| i); |
| |
| if (gdbarch_vtable_function_descriptors (gdbarch)) |
| vfn = value_addr (vfn); |
| |
| TRY_CATCH (ex, RETURN_MASK_ERROR) |
| { |
| addr = value_as_address (vfn); |
| } |
| if (ex.reason < 0) |
| printf_filtered (_("<error: %s>"), ex.message); |
| else |
| print_function_pointer_address (opts, gdbarch, addr, gdb_stdout); |
| printf_filtered ("\n"); |
| } |
| } |
| |
| /* Implementation of the print_vtable method. */ |
| |
| static void |
| gnuv3_print_vtable (struct value *value) |
| { |
| struct gdbarch *gdbarch; |
| struct type *type; |
| struct value *vtable; |
| struct value_print_options opts; |
| htab_t offset_hash; |
| struct cleanup *cleanup; |
| VEC (value_and_voffset_p) *result_vec = NULL; |
| struct value_and_voffset *iter; |
| int i, count; |
| |
| value = coerce_ref (value); |
| type = check_typedef (value_type (value)); |
| if (TYPE_CODE (type) == TYPE_CODE_PTR) |
| { |
| value = value_ind (value); |
| type = check_typedef (value_type (value)); |
| } |
| |
| get_user_print_options (&opts); |
| |
| /* Respect 'set print object'. */ |
| if (opts.objectprint) |
| { |
| value = value_full_object (value, NULL, 0, 0, 0); |
| type = check_typedef (value_type (value)); |
| } |
| |
| gdbarch = get_type_arch (type); |
| vtable = gnuv3_get_vtable (gdbarch, type, |
| value_as_address (value_addr (value))); |
| |
| if (!vtable) |
| { |
| printf_filtered (_("This object does not have a virtual function table\n")); |
| return; |
| } |
| |
| offset_hash = htab_create_alloc (1, hash_value_and_voffset, |
| eq_value_and_voffset, |
| xfree, xcalloc, xfree); |
| cleanup = make_cleanup_htab_delete (offset_hash); |
| make_cleanup (VEC_cleanup (value_and_voffset_p), &result_vec); |
| |
| compute_vtable_size (offset_hash, &result_vec, value); |
| |
| qsort (VEC_address (value_and_voffset_p, result_vec), |
| VEC_length (value_and_voffset_p, result_vec), |
| sizeof (value_and_voffset_p), |
| compare_value_and_voffset); |
| |
| count = 0; |
| for (i = 0; VEC_iterate (value_and_voffset_p, result_vec, i, iter); ++i) |
| { |
| if (iter->max_voffset >= 0) |
| { |
| if (count > 0) |
| printf_filtered ("\n"); |
| print_one_vtable (gdbarch, iter->value, iter->max_voffset, &opts); |
| ++count; |
| } |
| } |
| |
| do_cleanups (cleanup); |
| } |
| |
| /* 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; |
| struct gdbarch *gdbarch = get_frame_arch (frame); |
| struct 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 == 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 = SYMBOL_DEMANGLED_NAME (thunk_sym); |
| 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 == NULL) |
| return 0; |
| |
| method_stop_pc = SYMBOL_VALUE_ADDRESS (fn_sym); |
| real_stop_pc = gdbarch_skip_trampoline_code |
| (gdbarch, frame, method_stop_pc); |
| if (real_stop_pc == 0) |
| real_stop_pc = method_stop_pc; |
| |
| return real_stop_pc; |
| } |
| |
| /* Return nonzero if a type should be passed by reference. |
| |
| The rule in the v3 ABI document comes from section 3.1.1. If the |
| type has a non-trivial copy constructor or destructor, then the |
| caller must make a copy (by calling the copy constructor if there |
| is one or perform the copy itself otherwise), pass the address of |
| the copy, and then destroy the temporary (if necessary). |
| |
| For return values with non-trivial copy constructors or |
| destructors, space will be allocated in the caller, and a pointer |
| will be passed as the first argument (preceding "this"). |
| |
| We don't have a bulletproof mechanism for determining whether a |
| constructor or destructor is trivial. For GCC and DWARF2 debug |
| information, we can check the artificial flag. |
| |
| We don't do anything with the constructors or destructors, |
| but we have to get the argument passing right anyway. */ |
| static int |
| gnuv3_pass_by_reference (struct type *type) |
| { |
| int fieldnum, fieldelem; |
| |
| CHECK_TYPEDEF (type); |
| |
| /* We're only interested in things that can have methods. */ |
| if (TYPE_CODE (type) != TYPE_CODE_STRUCT |
| && TYPE_CODE (type) != TYPE_CODE_CLASS |
| && TYPE_CODE (type) != TYPE_CODE_UNION) |
| return 0; |
| |
| for (fieldnum = 0; fieldnum < TYPE_NFN_FIELDS (type); fieldnum++) |
| for (fieldelem = 0; fieldelem < TYPE_FN_FIELDLIST_LENGTH (type, fieldnum); |
| fieldelem++) |
| { |
| struct fn_field *fn = TYPE_FN_FIELDLIST1 (type, fieldnum); |
| const char *name = TYPE_FN_FIELDLIST_NAME (type, fieldnum); |
| struct type *fieldtype = TYPE_FN_FIELD_TYPE (fn, fieldelem); |
| |
| /* If this function is marked as artificial, it is compiler-generated, |
| and we assume it is trivial. */ |
| if (TYPE_FN_FIELD_ARTIFICIAL (fn, fieldelem)) |
| continue; |
| |
| /* If we've found a destructor, we must pass this by reference. */ |
| if (name[0] == '~') |
| return 1; |
| |
| /* If the mangled name of this method doesn't indicate that it |
| is a constructor, we're not interested. |
| |
| FIXME drow/2007-09-23: We could do this using the name of |
| the method and the name of the class instead of dealing |
| with the mangled name. We don't have a convenient function |
| to strip off both leading scope qualifiers and trailing |
| template arguments yet. */ |
| if (!is_constructor_name (TYPE_FN_FIELD_PHYSNAME (fn, fieldelem))) |
| continue; |
| |
| /* If this method takes two arguments, and the second argument is |
| a reference to this class, then it is a copy constructor. */ |
| if (TYPE_NFIELDS (fieldtype) == 2 |
| && TYPE_CODE (TYPE_FIELD_TYPE (fieldtype, 1)) == TYPE_CODE_REF |
| && check_typedef (TYPE_TARGET_TYPE (TYPE_FIELD_TYPE (fieldtype, |
| 1))) == type) |
| return 1; |
| } |
| |
| /* Even if all the constructors and destructors were artificial, one |
| of them may have invoked a non-artificial constructor or |
| destructor in a base class. If any base class needs to be passed |
| by reference, so does this class. Similarly for members, which |
| are constructed whenever this class is. We do not need to worry |
| about recursive loops here, since we are only looking at members |
| of complete class type. Also ignore any static members. */ |
| for (fieldnum = 0; fieldnum < TYPE_NFIELDS (type); fieldnum++) |
| if (! field_is_static (&TYPE_FIELD (type, fieldnum)) |
| && gnuv3_pass_by_reference (TYPE_FIELD_TYPE (type, fieldnum))) |
| return 1; |
| |
| return 0; |
| } |
| |
| static void |
| init_gnuv3_ops (void) |
| { |
| vtable_type_gdbarch_data |
| = gdbarch_data_register_post_init (build_gdb_vtable_type); |
| |
| 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.skip_trampoline = gnuv3_skip_trampoline; |
| gnu_v3_abi_ops.pass_by_reference = gnuv3_pass_by_reference; |
| } |
| |
| extern initialize_file_ftype _initialize_gnu_v3_abi; /* -Wmissing-prototypes */ |
| |
| void |
| _initialize_gnu_v3_abi (void) |
| { |
| init_gnuv3_ops (); |
| |
| register_cp_abi (&gnu_v3_abi_ops); |
| } |