1 /* Abstraction of GNU v2 abi.
3 Copyright (C) 2001, 2002, 2003, 2005, 2007 Free Software Foundation, Inc.
5 Contributed by Daniel Berlin <dberlin@redhat.com>
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "gdb_string.h"
29 #include "cp-support.h"
30 #include "gnu-v2-abi.h"
34 struct cp_abi_ops gnu_v2_abi_ops
;
36 static int vb_match (struct type
*, int, struct type
*);
38 static enum dtor_kinds
39 gnuv2_is_destructor_name (const char *name
)
41 if ((name
[0] == '_' && is_cplus_marker (name
[1]) && name
[2] == '_')
42 || strncmp (name
, "__dt__", 6) == 0)
43 return complete_object_dtor
;
48 static enum ctor_kinds
49 gnuv2_is_constructor_name (const char *name
)
51 if ((name
[0] == '_' && name
[1] == '_'
52 && (isdigit (name
[2]) || strchr ("Qt", name
[2])))
53 || strncmp (name
, "__ct__", 6) == 0)
54 return complete_object_ctor
;
60 gnuv2_is_vtable_name (const char *name
)
62 return (((name
)[0] == '_'
63 && (((name
)[1] == 'V' && (name
)[2] == 'T')
64 || ((name
)[1] == 'v' && (name
)[2] == 't'))
65 && is_cplus_marker ((name
)[3])) ||
66 ((name
)[0] == '_' && (name
)[1] == '_'
67 && (name
)[2] == 'v' && (name
)[3] == 't' && (name
)[4] == '_'));
71 gnuv2_is_operator_name (const char *name
)
73 return strncmp (name
, "operator", 8) == 0;
77 /* Return a virtual function as a value.
78 ARG1 is the object which provides the virtual function
79 table pointer. *ARG1P is side-effected in calling this function.
80 F is the list of member functions which contains the desired virtual
82 J is an index into F which provides the desired virtual function.
84 TYPE is the type in which F is located. */
86 gnuv2_virtual_fn_field (struct value
**arg1p
, struct fn_field
* f
, int j
,
87 struct type
* type
, int offset
)
89 struct value
*arg1
= *arg1p
;
90 struct type
*type1
= check_typedef (value_type (arg1
));
93 struct type
*entry_type
;
94 /* First, get the virtual function table pointer. That comes
95 with a strange type, so cast it to type `pointer to long' (which
96 should serve just fine as a function type). Then, index into
97 the table, and convert final value to appropriate function type. */
101 struct value
*vi
= value_from_longest (builtin_type_int
,
102 (LONGEST
) TYPE_FN_FIELD_VOFFSET (f
, j
));
103 struct type
*fcontext
= TYPE_FN_FIELD_FCONTEXT (f
, j
);
104 struct type
*context
;
105 if (fcontext
== NULL
)
106 /* We don't have an fcontext (e.g. the program was compiled with
107 g++ version 1). Try to get the vtbl from the TYPE_VPTR_BASETYPE.
108 This won't work right for multiple inheritance, but at least we
109 should do as well as GDB 3.x did. */
110 fcontext
= TYPE_VPTR_BASETYPE (type
);
111 context
= lookup_pointer_type (fcontext
);
112 /* Now context is a pointer to the basetype containing the vtbl. */
113 if (TYPE_TARGET_TYPE (context
) != type1
)
115 struct value
*tmp
= value_cast (context
, value_addr (arg1
));
116 arg1
= value_ind (tmp
);
117 type1
= check_typedef (value_type (arg1
));
121 /* Now context is the basetype containing the vtbl. */
123 /* This type may have been defined before its virtual function table
124 was. If so, fill in the virtual function table entry for the
126 if (TYPE_VPTR_FIELDNO (context
) < 0)
127 fill_in_vptr_fieldno (context
);
129 /* The virtual function table is now an array of structures
130 which have the form { int16 offset, delta; void *pfn; }. */
131 vtbl
= value_primitive_field (arg1
, 0, TYPE_VPTR_FIELDNO (context
),
132 TYPE_VPTR_BASETYPE (context
));
134 /* With older versions of g++, the vtbl field pointed to an array
135 of structures. Nowadays it points directly to the structure. */
136 if (TYPE_CODE (value_type (vtbl
)) == TYPE_CODE_PTR
137 && TYPE_CODE (TYPE_TARGET_TYPE (value_type (vtbl
))) == TYPE_CODE_ARRAY
)
139 /* Handle the case where the vtbl field points to an
140 array of structures. */
141 vtbl
= value_ind (vtbl
);
143 /* Index into the virtual function table. This is hard-coded because
144 looking up a field is not cheap, and it may be important to save
145 time, e.g. if the user has set a conditional breakpoint calling
146 a virtual function. */
147 entry
= value_subscript (vtbl
, vi
);
151 /* Handle the case where the vtbl field points directly to a structure. */
152 vtbl
= value_add (vtbl
, vi
);
153 entry
= value_ind (vtbl
);
156 entry_type
= check_typedef (value_type (entry
));
158 if (TYPE_CODE (entry_type
) == TYPE_CODE_STRUCT
)
160 /* Move the `this' pointer according to the virtual function table. */
161 set_value_offset (arg1
, value_offset (arg1
) + value_as_long (value_field (entry
, 0)));
163 if (!value_lazy (arg1
))
165 set_value_lazy (arg1
, 1);
166 value_fetch_lazy (arg1
);
169 vfn
= value_field (entry
, 2);
171 else if (TYPE_CODE (entry_type
) == TYPE_CODE_PTR
)
174 error (_("I'm confused: virtual function table has bad type"));
175 /* Reinstantiate the function pointer with the correct type. */
176 deprecated_set_value_type (vfn
, lookup_pointer_type (TYPE_FN_FIELD_TYPE (f
, j
)));
184 gnuv2_value_rtti_type (struct value
*v
, int *full
, int *top
, int *using_enc
)
186 struct type
*known_type
;
187 struct type
*rtti_type
;
191 char rtti_type_name
[256];
193 struct minimal_symbol
*minsym
;
195 char *demangled_name
, *p
;
205 /* Get declared type */
206 known_type
= value_type (v
);
207 CHECK_TYPEDEF (known_type
);
208 /* RTTI works only or class objects */
209 if (TYPE_CODE (known_type
) != TYPE_CODE_CLASS
)
212 /* Plan on this changing in the future as i get around to setting
213 the vtables properly for G++ compiled stuff. Also, I'll be using
214 the type info functions, which are always right. Deal with it
217 /* If the type has no vptr fieldno, try to get it filled in */
218 if (TYPE_VPTR_FIELDNO(known_type
) < 0)
219 fill_in_vptr_fieldno(known_type
);
221 /* If we still can't find one, give up */
222 if (TYPE_VPTR_FIELDNO(known_type
) < 0)
225 /* Make sure our basetype and known type match, otherwise, cast
226 so we can get at the vtable properly.
228 btype
= TYPE_VPTR_BASETYPE (known_type
);
229 CHECK_TYPEDEF (btype
);
230 if (btype
!= known_type
)
232 v
= value_cast (btype
, v
);
237 We can't use value_ind here, because it would want to use RTTI, and
238 we'd waste a bunch of time figuring out we already know the type.
239 Besides, we don't care about the type, just the actual pointer
241 if (VALUE_ADDRESS (value_field (v
, TYPE_VPTR_FIELDNO (known_type
))) == 0)
244 vtbl
=value_as_address(value_field(v
,TYPE_VPTR_FIELDNO(known_type
)));
246 /* Try to find a symbol that is the vtable */
247 minsym
=lookup_minimal_symbol_by_pc(vtbl
);
249 || (demangled_name
=DEPRECATED_SYMBOL_NAME (minsym
))==NULL
250 || !is_vtable_name (demangled_name
))
253 /* If we just skip the prefix, we get screwed by namespaces */
254 demangled_name
=cplus_demangle(demangled_name
,DMGL_PARAMS
|DMGL_ANSI
);
255 p
= strchr (demangled_name
, ' ');
259 /* Lookup the type for the name */
260 /* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */
261 rtti_type
= cp_lookup_rtti_type (demangled_name
, NULL
);
262 if (rtti_type
== NULL
)
265 if (TYPE_N_BASECLASSES(rtti_type
) > 1 && full
&& (*full
) != 1)
268 *top
=TYPE_BASECLASS_BITPOS(rtti_type
,TYPE_VPTR_FIELDNO(rtti_type
))/8;
269 if (top
&& ((*top
) >0))
271 if (TYPE_LENGTH(rtti_type
) > TYPE_LENGTH(known_type
))
292 /* Return true if the INDEXth field of TYPE is a virtual baseclass
293 pointer which is for the base class whose type is BASECLASS. */
296 vb_match (struct type
*type
, int index
, struct type
*basetype
)
298 struct type
*fieldtype
;
299 char *name
= TYPE_FIELD_NAME (type
, index
);
300 char *field_class_name
= NULL
;
304 /* gcc 2.4 uses _vb$. */
305 if (name
[1] == 'v' && name
[2] == 'b' && is_cplus_marker (name
[3]))
306 field_class_name
= name
+ 4;
307 /* gcc 2.5 will use __vb_. */
308 if (name
[1] == '_' && name
[2] == 'v' && name
[3] == 'b' && name
[4] == '_')
309 field_class_name
= name
+ 5;
311 if (field_class_name
== NULL
)
312 /* This field is not a virtual base class pointer. */
315 /* It's a virtual baseclass pointer, now we just need to find out whether
316 it is for this baseclass. */
317 fieldtype
= TYPE_FIELD_TYPE (type
, index
);
318 if (fieldtype
== NULL
319 || TYPE_CODE (fieldtype
) != TYPE_CODE_PTR
)
320 /* "Can't happen". */
323 /* What we check for is that either the types are equal (needed for
324 nameless types) or have the same name. This is ugly, and a more
325 elegant solution should be devised (which would probably just push
326 the ugliness into symbol reading unless we change the stabs format). */
327 if (TYPE_TARGET_TYPE (fieldtype
) == basetype
)
330 if (TYPE_NAME (basetype
) != NULL
331 && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
)) != NULL
332 && strcmp (TYPE_NAME (basetype
),
333 TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
))) == 0)
338 /* Compute the offset of the baseclass which is
339 the INDEXth baseclass of class TYPE,
340 for value at VALADDR (in host) at ADDRESS (in target).
341 The result is the offset of the baseclass value relative
342 to (the address of)(ARG) + OFFSET.
344 -1 is returned on error. */
347 gnuv2_baseclass_offset (struct type
*type
, int index
,
348 const bfd_byte
*valaddr
, CORE_ADDR address
)
350 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
352 if (BASETYPE_VIA_VIRTUAL (type
, index
))
354 /* Must hunt for the pointer to this virtual baseclass. */
355 int i
, len
= TYPE_NFIELDS (type
);
356 int n_baseclasses
= TYPE_N_BASECLASSES (type
);
358 /* First look for the virtual baseclass pointer
360 for (i
= n_baseclasses
; i
< len
; i
++)
362 if (vb_match (type
, i
, basetype
))
365 = unpack_pointer (TYPE_FIELD_TYPE (type
, i
),
366 valaddr
+ (TYPE_FIELD_BITPOS (type
, i
) / 8));
368 return addr
- (LONGEST
) address
;
371 /* Not in the fields, so try looking through the baseclasses. */
372 for (i
= index
+ 1; i
< n_baseclasses
; i
++)
375 baseclass_offset (type
, i
, valaddr
, address
);
383 /* Baseclass is easily computed. */
384 return TYPE_BASECLASS_BITPOS (type
, index
) / 8;
388 init_gnuv2_ops (void)
390 gnu_v2_abi_ops
.shortname
= "gnu-v2";
391 gnu_v2_abi_ops
.longname
= "GNU G++ Version 2 ABI";
392 gnu_v2_abi_ops
.doc
= "G++ Version 2 ABI";
393 gnu_v2_abi_ops
.is_destructor_name
= gnuv2_is_destructor_name
;
394 gnu_v2_abi_ops
.is_constructor_name
= gnuv2_is_constructor_name
;
395 gnu_v2_abi_ops
.is_vtable_name
= gnuv2_is_vtable_name
;
396 gnu_v2_abi_ops
.is_operator_name
= gnuv2_is_operator_name
;
397 gnu_v2_abi_ops
.virtual_fn_field
= gnuv2_virtual_fn_field
;
398 gnu_v2_abi_ops
.rtti_type
= gnuv2_value_rtti_type
;
399 gnu_v2_abi_ops
.baseclass_offset
= gnuv2_baseclass_offset
;
402 extern initialize_file_ftype _initialize_gnu_v2_abi
; /* -Wmissing-prototypes */
405 _initialize_gnu_v2_abi (void)
408 register_cp_abi (&gnu_v2_abi_ops
);
409 set_cp_abi_as_auto_default (gnu_v2_abi_ops
.shortname
);