1 /* Abstraction of GNU v2 abi.
3 Copyright (C) 2001, 2002, 2003, 2005, 2007, 2008, 2009, 2010
4 Free Software Foundation, Inc.
6 Contributed by Daniel Berlin <dberlin@redhat.com>
8 This file is part of GDB.
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "gdb_string.h"
30 #include "cp-support.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
));
91 struct type
*entry_type
;
92 /* First, get the virtual function table pointer. That comes
93 with a strange type, so cast it to type `pointer to long' (which
94 should serve just fine as a function type). Then, index into
95 the table, and convert final value to appropriate function type. */
99 LONGEST vi
= (LONGEST
) TYPE_FN_FIELD_VOFFSET (f
, j
);
100 struct type
*fcontext
= TYPE_FN_FIELD_FCONTEXT (f
, j
);
101 struct type
*context
;
102 struct type
*context_vptr_basetype
;
103 int context_vptr_fieldno
;
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 context_vptr_fieldno
= get_vptr_fieldno (context
, &context_vptr_basetype
);
127 /* FIXME: What to do if vptr_fieldno is still -1? */
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, context_vptr_fieldno
,
132 context_vptr_basetype
);
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_ptradd (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
;
189 struct minimal_symbol
*minsym
;
190 char *demangled_name
, *p
;
192 struct type
*known_type_vptr_basetype
;
193 int known_type_vptr_fieldno
;
202 /* Get declared type */
203 known_type
= value_type (v
);
204 CHECK_TYPEDEF (known_type
);
205 /* RTTI works only or class objects */
206 if (TYPE_CODE (known_type
) != TYPE_CODE_CLASS
)
209 /* Plan on this changing in the future as i get around to setting
210 the vtables properly for G++ compiled stuff. Also, I'll be using
211 the type info functions, which are always right. Deal with it
214 /* Try to get the vptr basetype, fieldno. */
215 known_type_vptr_fieldno
= get_vptr_fieldno (known_type
,
216 &known_type_vptr_basetype
);
218 /* If we can't find it, give up. */
219 if (known_type_vptr_fieldno
< 0)
222 /* Make sure our basetype and known type match, otherwise, cast
223 so we can get at the vtable properly.
225 btype
= known_type_vptr_basetype
;
226 CHECK_TYPEDEF (btype
);
227 if (btype
!= known_type
)
229 v
= value_cast (btype
, v
);
234 We can't use value_ind here, because it would want to use RTTI, and
235 we'd waste a bunch of time figuring out we already know the type.
236 Besides, we don't care about the type, just the actual pointer
238 if (value_address (value_field (v
, known_type_vptr_fieldno
)) == 0)
241 vtbl
= value_as_address (value_field (v
, known_type_vptr_fieldno
));
243 /* Try to find a symbol that is the vtable */
244 minsym
=lookup_minimal_symbol_by_pc(vtbl
);
246 || (demangled_name
=SYMBOL_LINKAGE_NAME (minsym
))==NULL
247 || !is_vtable_name (demangled_name
))
250 /* If we just skip the prefix, we get screwed by namespaces */
251 demangled_name
=cplus_demangle(demangled_name
,DMGL_PARAMS
|DMGL_ANSI
);
252 p
= strchr (demangled_name
, ' ');
256 /* Lookup the type for the name */
257 /* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */
258 rtti_type
= cp_lookup_rtti_type (demangled_name
, NULL
);
259 if (rtti_type
== NULL
)
262 if (TYPE_N_BASECLASSES(rtti_type
) > 1 && full
&& (*full
) != 1)
265 *top
=TYPE_BASECLASS_BITPOS(rtti_type
,TYPE_VPTR_FIELDNO(rtti_type
))/8;
266 if (top
&& ((*top
) >0))
268 if (TYPE_LENGTH(rtti_type
) > TYPE_LENGTH(known_type
))
289 /* Return true if the INDEXth field of TYPE is a virtual baseclass
290 pointer which is for the base class whose type is BASECLASS. */
293 vb_match (struct type
*type
, int index
, struct type
*basetype
)
295 struct type
*fieldtype
;
296 char *name
= TYPE_FIELD_NAME (type
, index
);
297 char *field_class_name
= NULL
;
301 /* gcc 2.4 uses _vb$. */
302 if (name
[1] == 'v' && name
[2] == 'b' && is_cplus_marker (name
[3]))
303 field_class_name
= name
+ 4;
304 /* gcc 2.5 will use __vb_. */
305 if (name
[1] == '_' && name
[2] == 'v' && name
[3] == 'b' && name
[4] == '_')
306 field_class_name
= name
+ 5;
308 if (field_class_name
== NULL
)
309 /* This field is not a virtual base class pointer. */
312 /* It's a virtual baseclass pointer, now we just need to find out whether
313 it is for this baseclass. */
314 fieldtype
= TYPE_FIELD_TYPE (type
, index
);
315 if (fieldtype
== NULL
316 || TYPE_CODE (fieldtype
) != TYPE_CODE_PTR
)
317 /* "Can't happen". */
320 /* What we check for is that either the types are equal (needed for
321 nameless types) or have the same name. This is ugly, and a more
322 elegant solution should be devised (which would probably just push
323 the ugliness into symbol reading unless we change the stabs format). */
324 if (TYPE_TARGET_TYPE (fieldtype
) == basetype
)
327 if (TYPE_NAME (basetype
) != NULL
328 && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
)) != NULL
329 && strcmp (TYPE_NAME (basetype
),
330 TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
))) == 0)
335 /* Compute the offset of the baseclass which is
336 the INDEXth baseclass of class TYPE,
337 for value at VALADDR (in host) at ADDRESS (in target).
338 The result is the offset of the baseclass value relative
339 to (the address of)(ARG) + OFFSET.
341 -1 is returned on error. */
344 gnuv2_baseclass_offset (struct type
*type
, int index
,
345 const bfd_byte
*valaddr
, CORE_ADDR address
)
347 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
349 if (BASETYPE_VIA_VIRTUAL (type
, index
))
351 /* Must hunt for the pointer to this virtual baseclass. */
352 int i
, len
= TYPE_NFIELDS (type
);
353 int n_baseclasses
= TYPE_N_BASECLASSES (type
);
355 /* First look for the virtual baseclass pointer
357 for (i
= n_baseclasses
; i
< len
; i
++)
359 if (vb_match (type
, i
, basetype
))
362 = unpack_pointer (TYPE_FIELD_TYPE (type
, i
),
363 valaddr
+ (TYPE_FIELD_BITPOS (type
, i
) / 8));
365 return addr
- (LONGEST
) address
;
368 /* Not in the fields, so try looking through the baseclasses. */
369 for (i
= index
+ 1; i
< n_baseclasses
; i
++)
372 baseclass_offset (type
, i
, valaddr
, address
);
380 /* Baseclass is easily computed. */
381 return TYPE_BASECLASS_BITPOS (type
, index
) / 8;
385 init_gnuv2_ops (void)
387 gnu_v2_abi_ops
.shortname
= "gnu-v2";
388 gnu_v2_abi_ops
.longname
= "GNU G++ Version 2 ABI";
389 gnu_v2_abi_ops
.doc
= "G++ Version 2 ABI";
390 gnu_v2_abi_ops
.is_destructor_name
= gnuv2_is_destructor_name
;
391 gnu_v2_abi_ops
.is_constructor_name
= gnuv2_is_constructor_name
;
392 gnu_v2_abi_ops
.is_vtable_name
= gnuv2_is_vtable_name
;
393 gnu_v2_abi_ops
.is_operator_name
= gnuv2_is_operator_name
;
394 gnu_v2_abi_ops
.virtual_fn_field
= gnuv2_virtual_fn_field
;
395 gnu_v2_abi_ops
.rtti_type
= gnuv2_value_rtti_type
;
396 gnu_v2_abi_ops
.baseclass_offset
= gnuv2_baseclass_offset
;
399 extern initialize_file_ftype _initialize_gnu_v2_abi
; /* -Wmissing-prototypes */
402 _initialize_gnu_v2_abi (void)
405 register_cp_abi (&gnu_v2_abi_ops
);
406 set_cp_abi_as_auto_default (gnu_v2_abi_ops
.shortname
);