binutils-gdb/gdb/gnu-v2-abi.c

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/* Abstraction of GNU v2 abi.
Contributed by Daniel Berlin <dberlin@redhat.com>
Copyright 2001 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 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 <ctype.h>
struct cp_abi_ops gnu_v2_abi_ops;
static int vb_match (struct type *, int, struct type *);
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 value_ptr
gnuv2_virtual_fn_field (value_ptr * arg1p, struct fn_field * f, int j,
struct type * type, int offset)
{
value_ptr 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. */
value_ptr entry, vfn, vtbl;
value_ptr 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)
{
value_ptr tmp = value_cast (context, value_addr (arg1));
VALUE_POINTED_TO_OFFSET (tmp) = 0;
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;
}
struct type *
gnuv2_value_rtti_type (value_ptr v, int *full, int *top, int *using_enc)
{
struct type *known_type;
struct type *rtti_type;
CORE_ADDR coreptr;
value_ptr vp;
int using_enclosing = 0;
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;
/*
If we are enclosed by something that isn't us, adjust the
address properly and set using_enclosing.
*/
if (VALUE_ENCLOSING_TYPE(v) != VALUE_TYPE(v))
{
value_ptr tempval;
int bitpos = TYPE_BASECLASS_BITPOS (known_type,
TYPE_VPTR_FIELDNO (known_type));
tempval=value_field (v, TYPE_VPTR_FIELDNO(known_type));
VALUE_ADDRESS(tempval) += bitpos / 8;
vtbl=value_as_pointer (tempval);
using_enclosing=1;
}
else
{
vtbl=value_as_pointer(value_field(v,TYPE_VPTR_FIELDNO(known_type)));
using_enclosing=0;
}
/* Try to find a symbol that is the vtable */
minsym=lookup_minimal_symbol_by_pc(vtbl);
if (minsym==NULL
|| (demangled_name=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 */
rtti_type=lookup_typename(demangled_name, (struct block *)0,1);
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;
}
if (using_enc)
*using_enc=using_enclosing;
return rtti_type;
}
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;
}
void
_initialize_gnu_v2_abi (void)
{
init_gnuv2_ops ();
register_cp_abi (gnu_v2_abi_ops);
switch_to_cp_abi ("gnu-v2");
}