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| Current File : //usr/src/contrib/gdb/gdb/gnu-v2-abi.c |
/* Abstraction of GNU v2 abi.
Copyright 2001, 2002, 2003 Free Software Foundation, Inc.
Contributed by Daniel Berlin <dberlin@redhat.com>
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 2 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, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include "defs.h"
#include "gdb_string.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "value.h"
#include "demangle.h"
#include "cp-abi.h"
#include "cp-support.h"
#include <ctype.h>
struct cp_abi_ops gnu_v2_abi_ops;
static int vb_match (struct type *, int, struct type *);
int gnuv2_baseclass_offset (struct type *type, int index, char *valaddr,
CORE_ADDR address);
static enum dtor_kinds
gnuv2_is_destructor_name (const char *name)
{
if ((name[0] == '_' && is_cplus_marker (name[1]) && name[2] == '_')
|| strncmp (name, "__dt__", 6) == 0)
return complete_object_dtor;
else
return 0;
}
static enum ctor_kinds
gnuv2_is_constructor_name (const char *name)
{
if ((name[0] == '_' && name[1] == '_'
&& (isdigit (name[2]) || strchr ("Qt", name[2])))
|| strncmp (name, "__ct__", 6) == 0)
return complete_object_ctor;
else
return 0;
}
static int
gnuv2_is_vtable_name (const char *name)
{
return (((name)[0] == '_'
&& (((name)[1] == 'V' && (name)[2] == 'T')
|| ((name)[1] == 'v' && (name)[2] == 't'))
&& is_cplus_marker ((name)[3])) ||
((name)[0] == '_' && (name)[1] == '_'
&& (name)[2] == 'v' && (name)[3] == 't' && (name)[4] == '_'));
}
static int
gnuv2_is_operator_name (const char *name)
{
return strncmp (name, "operator", 8) == 0;
}
/* Return a virtual function as a value.
ARG1 is the object which provides the virtual function
table pointer. *ARG1P is side-effected in calling this function.
F is the list of member functions which contains the desired virtual
function.
J is an index into F which provides the desired virtual function.
TYPE is the type in which F is located. */
static struct value *
gnuv2_virtual_fn_field (struct value **arg1p, struct fn_field * f, int j,
struct type * type, int offset)
{
struct value *arg1 = *arg1p;
struct type *type1 = check_typedef (VALUE_TYPE (arg1));
struct type *entry_type;
/* First, get the virtual function table pointer. That comes
with a strange type, so cast it to type `pointer to long' (which
should serve just fine as a function type). Then, index into
the table, and convert final value to appropriate function type. */
struct value *entry;
struct value *vfn;
struct value *vtbl;
struct value *vi = value_from_longest (builtin_type_int,
(LONGEST) TYPE_FN_FIELD_VOFFSET (f, j));
struct type *fcontext = TYPE_FN_FIELD_FCONTEXT (f, j);
struct type *context;
if (fcontext == NULL)
/* We don't have an fcontext (e.g. the program was compiled with
g++ version 1). Try to get the vtbl from the TYPE_VPTR_BASETYPE.
This won't work right for multiple inheritance, but at least we
should do as well as GDB 3.x did. */
fcontext = TYPE_VPTR_BASETYPE (type);
context = lookup_pointer_type (fcontext);
/* Now context is a pointer to the basetype containing the vtbl. */
if (TYPE_TARGET_TYPE (context) != type1)
{
struct value *tmp = value_cast (context, value_addr (arg1));
arg1 = value_ind (tmp);
type1 = check_typedef (VALUE_TYPE (arg1));
}
context = type1;
/* Now context is the basetype containing the vtbl. */
/* This type may have been defined before its virtual function table
was. If so, fill in the virtual function table entry for the
type now. */
if (TYPE_VPTR_FIELDNO (context) < 0)
fill_in_vptr_fieldno (context);
/* The virtual function table is now an array of structures
which have the form { int16 offset, delta; void *pfn; }. */
vtbl = value_primitive_field (arg1, 0, TYPE_VPTR_FIELDNO (context),
TYPE_VPTR_BASETYPE (context));
/* With older versions of g++, the vtbl field pointed to an array
of structures. Nowadays it points directly to the structure. */
if (TYPE_CODE (VALUE_TYPE (vtbl)) == TYPE_CODE_PTR
&& TYPE_CODE (TYPE_TARGET_TYPE (VALUE_TYPE (vtbl))) == TYPE_CODE_ARRAY)
{
/* Handle the case where the vtbl field points to an
array of structures. */
vtbl = value_ind (vtbl);
/* Index into the virtual function table. This is hard-coded because
looking up a field is not cheap, and it may be important to save
time, e.g. if the user has set a conditional breakpoint calling
a virtual function. */
entry = value_subscript (vtbl, vi);
}
else
{
/* Handle the case where the vtbl field points directly to a structure. */
vtbl = value_add (vtbl, vi);
entry = value_ind (vtbl);
}
entry_type = check_typedef (VALUE_TYPE (entry));
if (TYPE_CODE (entry_type) == TYPE_CODE_STRUCT)
{
/* Move the `this' pointer according to the virtual function table. */
VALUE_OFFSET (arg1) += value_as_long (value_field (entry, 0));
if (!VALUE_LAZY (arg1))
{
VALUE_LAZY (arg1) = 1;
value_fetch_lazy (arg1);
}
vfn = value_field (entry, 2);
}
else if (TYPE_CODE (entry_type) == TYPE_CODE_PTR)
vfn = entry;
else
error ("I'm confused: virtual function table has bad type");
/* Reinstantiate the function pointer with the correct type. */
VALUE_TYPE (vfn) = lookup_pointer_type (TYPE_FN_FIELD_TYPE (f, j));
*arg1p = arg1;
return vfn;
}
static struct type *
gnuv2_value_rtti_type (struct value *v, int *full, int *top, int *using_enc)
{
struct type *known_type;
struct type *rtti_type;
CORE_ADDR coreptr;
struct value *vp;
long top_offset = 0;
char rtti_type_name[256];
CORE_ADDR vtbl;
struct minimal_symbol *minsym;
struct symbol *sym;
char *demangled_name;
struct type *btype;
if (full)
*full = 0;
if (top)
*top = -1;
if (using_enc)
*using_enc = 0;
/* Get declared type */
known_type = VALUE_TYPE (v);
CHECK_TYPEDEF (known_type);
/* RTTI works only or class objects */
if (TYPE_CODE (known_type) != TYPE_CODE_CLASS)
return NULL;
/* Plan on this changing in the future as i get around to setting
the vtables properly for G++ compiled stuff. Also, I'll be using
the type info functions, which are always right. Deal with it
until then. */
/* If the type has no vptr fieldno, try to get it filled in */
if (TYPE_VPTR_FIELDNO(known_type) < 0)
fill_in_vptr_fieldno(known_type);
/* If we still can't find one, give up */
if (TYPE_VPTR_FIELDNO(known_type) < 0)
return NULL;
/* Make sure our basetype and known type match, otherwise, cast
so we can get at the vtable properly.
*/
btype = TYPE_VPTR_BASETYPE (known_type);
CHECK_TYPEDEF (btype);
if (btype != known_type )
{
v = value_cast (btype, v);
if (using_enc)
*using_enc=1;
}
/*
We can't use value_ind here, because it would want to use RTTI, and
we'd waste a bunch of time figuring out we already know the type.
Besides, we don't care about the type, just the actual pointer
*/
if (VALUE_ADDRESS (value_field (v, TYPE_VPTR_FIELDNO (known_type))) == 0)
return NULL;
vtbl=value_as_address(value_field(v,TYPE_VPTR_FIELDNO(known_type)));
/* Try to find a symbol that is the vtable */
minsym=lookup_minimal_symbol_by_pc(vtbl);
if (minsym==NULL
|| (demangled_name=DEPRECATED_SYMBOL_NAME (minsym))==NULL
|| !is_vtable_name (demangled_name))
return NULL;
/* If we just skip the prefix, we get screwed by namespaces */
demangled_name=cplus_demangle(demangled_name,DMGL_PARAMS|DMGL_ANSI);
*(strchr(demangled_name,' '))=0;
/* Lookup the type for the name */
/* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */
rtti_type = cp_lookup_rtti_type (demangled_name, NULL);
if (rtti_type == NULL)
return NULL;
if (TYPE_N_BASECLASSES(rtti_type) > 1 && full && (*full) != 1)
{
if (top)
*top=TYPE_BASECLASS_BITPOS(rtti_type,TYPE_VPTR_FIELDNO(rtti_type))/8;
if (top && ((*top) >0))
{
if (TYPE_LENGTH(rtti_type) > TYPE_LENGTH(known_type))
{
if (full)
*full=0;
}
else
{
if (full)
*full=1;
}
}
}
else
{
if (full)
*full=1;
}
return rtti_type;
}
/* Return true if the INDEXth field of TYPE is a virtual baseclass
pointer which is for the base class whose type is BASECLASS. */
static int
vb_match (struct type *type, int index, struct type *basetype)
{
struct type *fieldtype;
char *name = TYPE_FIELD_NAME (type, index);
char *field_class_name = NULL;
if (*name != '_')
return 0;
/* gcc 2.4 uses _vb$. */
if (name[1] == 'v' && name[2] == 'b' && is_cplus_marker (name[3]))
field_class_name = name + 4;
/* gcc 2.5 will use __vb_. */
if (name[1] == '_' && name[2] == 'v' && name[3] == 'b' && name[4] == '_')
field_class_name = name + 5;
if (field_class_name == NULL)
/* This field is not a virtual base class pointer. */
return 0;
/* It's a virtual baseclass pointer, now we just need to find out whether
it is for this baseclass. */
fieldtype = TYPE_FIELD_TYPE (type, index);
if (fieldtype == NULL
|| TYPE_CODE (fieldtype) != TYPE_CODE_PTR)
/* "Can't happen". */
return 0;
/* What we check for is that either the types are equal (needed for
nameless types) or have the same name. This is ugly, and a more
elegant solution should be devised (which would probably just push
the ugliness into symbol reading unless we change the stabs format). */
if (TYPE_TARGET_TYPE (fieldtype) == basetype)
return 1;
if (TYPE_NAME (basetype) != NULL
&& TYPE_NAME (TYPE_TARGET_TYPE (fieldtype)) != NULL
&& strcmp (TYPE_NAME (basetype),
TYPE_NAME (TYPE_TARGET_TYPE (fieldtype))) == 0)
return 1;
return 0;
}
/* 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. */
int
gnuv2_baseclass_offset (struct type *type, int index, char *valaddr,
CORE_ADDR address)
{
struct type *basetype = TYPE_BASECLASS (type, index);
if (BASETYPE_VIA_VIRTUAL (type, index))
{
/* Must hunt for the pointer to this virtual baseclass. */
int i, len = TYPE_NFIELDS (type);
int n_baseclasses = TYPE_N_BASECLASSES (type);
/* First look for the virtual baseclass pointer
in the fields. */
for (i = n_baseclasses; i < len; i++)
{
if (vb_match (type, i, basetype))
{
CORE_ADDR addr
= unpack_pointer (TYPE_FIELD_TYPE (type, i),
valaddr + (TYPE_FIELD_BITPOS (type, i) / 8));
return addr - (LONGEST) address;
}
}
/* Not in the fields, so try looking through the baseclasses. */
for (i = index + 1; i < n_baseclasses; i++)
{
int boffset =
baseclass_offset (type, i, valaddr, address);
if (boffset)
return boffset;
}
/* Not found. */
return -1;
}
/* Baseclass is easily computed. */
return TYPE_BASECLASS_BITPOS (type, index) / 8;
}
static void
init_gnuv2_ops (void)
{
gnu_v2_abi_ops.shortname = "gnu-v2";
gnu_v2_abi_ops.longname = "GNU G++ Version 2 ABI";
gnu_v2_abi_ops.doc = "G++ Version 2 ABI";
gnu_v2_abi_ops.is_destructor_name = gnuv2_is_destructor_name;
gnu_v2_abi_ops.is_constructor_name = gnuv2_is_constructor_name;
gnu_v2_abi_ops.is_vtable_name = gnuv2_is_vtable_name;
gnu_v2_abi_ops.is_operator_name = gnuv2_is_operator_name;
gnu_v2_abi_ops.virtual_fn_field = gnuv2_virtual_fn_field;
gnu_v2_abi_ops.rtti_type = gnuv2_value_rtti_type;
gnu_v2_abi_ops.baseclass_offset = gnuv2_baseclass_offset;
}
extern initialize_file_ftype _initialize_gnu_v2_abi; /* -Wmissing-prototypes */
void
_initialize_gnu_v2_abi (void)
{
init_gnuv2_ops ();
register_cp_abi (&gnu_v2_abi_ops);
set_cp_abi_as_auto_default (gnu_v2_abi_ops.shortname);
}