[deliverable/binutils-gdb.git] / gdb / gnu-v2-abi.c

/* Abstraction of GNU v2 abi.

   Copyright (C) 2001, 2002, 2003, 2005, 2007, 2008, 2009, 2010
   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 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 "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 *);

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;
}

\f
/* 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;
  LONGEST vi = (LONGEST) TYPE_FN_FIELD_VOFFSET (f, j);
  struct type *fcontext = TYPE_FN_FIELD_FCONTEXT (f, j);
  struct type *context;
  struct type *context_vptr_basetype;
  int context_vptr_fieldno;

  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.  */
  context_vptr_fieldno = get_vptr_fieldno (context, &context_vptr_basetype);
  /* FIXME: What to do if vptr_fieldno is still -1?  */

  /* 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, context_vptr_fieldno,
				context_vptr_basetype);

  /* 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_ptradd (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. */
      set_value_offset (arg1, value_offset (arg1) + value_as_long (value_field (entry, 0)));

      if (!value_lazy (arg1))
	{
	  set_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.  */
  deprecated_set_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, *p;
  struct type *btype;
  struct type *known_type_vptr_basetype;
  int known_type_vptr_fieldno;

  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.  */

  /* Try to get the vptr basetype, fieldno.  */
  known_type_vptr_fieldno = get_vptr_fieldno (known_type,
					      &known_type_vptr_basetype);

  /* If we can't find it, give up.  */
  if (known_type_vptr_fieldno < 0)
    return NULL;

  /* Make sure our basetype and known type match, otherwise, cast
     so we can get at the vtable properly.
  */
  btype = known_type_vptr_basetype;
  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, known_type_vptr_fieldno)) == 0)
    return NULL;

  vtbl = value_as_address (value_field (v, known_type_vptr_fieldno));

  /* Try to find a symbol that is the vtable */
  minsym=lookup_minimal_symbol_by_pc(vtbl);
  if (minsym==NULL
      || (demangled_name=SYMBOL_LINKAGE_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);
  p = strchr (demangled_name, ' ');
  if (p)
    *p = '\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. */

static int
gnuv2_baseclass_offset (struct type *type, int index,
			const bfd_byte *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);
}
Commit	Line	Data
015a42b4	1	/* Abstraction of GNU v2 abi.
1bac305b	2
4c38e0a4	3	Copyright (C) 2001, 2002, 2003, 2005, 2007, 2008, 2009, 2010
9b254dd1	4	Free Software Foundation, Inc.
1bac305b	5
015a42b4	6	Contributed by Daniel Berlin <dberlin@redhat.com>
015a42b4 JB	7
	8	This file is part of GDB.
	9
a9762ec7 JB	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
015a42b4 JB	13	(at your option) any later version.
	14
	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.
	19
	20	You should have received a copy of the GNU General Public License
a9762ec7	21	along with this program. If not, see <http://www.gnu.org/licenses/>. */
015a42b4 JB	22
015a42b4 JB	23	#include "defs.h"
015a42b4 JB	24	#include "gdb_string.h"
	25	#include "symtab.h"
	26	#include "gdbtypes.h"
	27	#include "value.h"
	28	#include "demangle.h"
	29	#include "cp-abi.h"
362ff856	30	#include "cp-support.h"
015a42b4 JB	31
	32	#include <ctype.h>
	33
	34	struct cp_abi_ops gnu_v2_abi_ops;
	35
	36	static int vb_match (struct type , int, struct type );
	37
	38	static enum dtor_kinds
	39	gnuv2_is_destructor_name (const char *name)
	40	{
	41	if ((name[0] == '_' && is_cplus_marker (name[1]) && name[2] == '_')
	42	\|\| strncmp (name, "__dt__", 6) == 0)
	43	return complete_object_dtor;
	44	else
	45	return 0;
	46	}
	47
	48	static enum ctor_kinds
	49	gnuv2_is_constructor_name (const char *name)
	50	{
	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;
	55	else
	56	return 0;
	57	}
	58
	59	static int
	60	gnuv2_is_vtable_name (const char *name)
	61	{
	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] == '_'));
	68	}
	69
	70	static int
	71	gnuv2_is_operator_name (const char *name)
	72	{
	73	return strncmp (name, "operator", 8) == 0;
	74	}
	75
	76	\f
	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
	81	function.
	82	J is an index into F which provides the desired virtual function.
	83
	84	TYPE is the type in which F is located. */
e933e538 AC	85	static struct value *
e933e538 AC	86	gnuv2_virtual_fn_field (struct value *arg1p, struct fn_field f, int j,
015a42b4 JB	87	struct type * type, int offset)
015a42b4 JB	88	{
e933e538	89	struct value arg1 = arg1p;
df407dfe	90	struct type *type1 = check_typedef (value_type (arg1));
015a42b4 JB	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. */
e933e538 AC	96	struct value *entry;
	97	struct value *vfn;
	98	struct value *vtbl;
2497b498	99	LONGEST vi = (LONGEST) TYPE_FN_FIELD_VOFFSET (f, j);
015a42b4 JB	100	struct type *fcontext = TYPE_FN_FIELD_FCONTEXT (f, j);
015a42b4 JB	101	struct type *context;
81fe8080 DE	102	struct type *context_vptr_basetype;
	103	int context_vptr_fieldno;
	104
015a42b4 JB	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)
	114	{
e933e538	115	struct value *tmp = value_cast (context, value_addr (arg1));
015a42b4	116	arg1 = value_ind (tmp);
df407dfe	117	type1 = check_typedef (value_type (arg1));
015a42b4 JB	118	}
	119
	120	context = type1;
	121	/* Now context is the basetype containing the vtbl. */
	122
	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
	125	type now. */
81fe8080 DE	126	context_vptr_fieldno = get_vptr_fieldno (context, &context_vptr_basetype);
81fe8080 DE	127	/* FIXME: What to do if vptr_fieldno is still -1? */
015a42b4 JB	128
	129	/* The virtual function table is now an array of structures
	130	which have the form { int16 offset, delta; void pfn; }. /
81fe8080 DE	131	vtbl = value_primitive_field (arg1, 0, context_vptr_fieldno,
81fe8080 DE	132	context_vptr_basetype);
015a42b4 JB	133
	134	/* With older versions of g++, the vtbl field pointed to an array
	135	of structures. Nowadays it points directly to the structure. */
df407dfe AC	136	if (TYPE_CODE (value_type (vtbl)) == TYPE_CODE_PTR
df407dfe AC	137	&& TYPE_CODE (TYPE_TARGET_TYPE (value_type (vtbl))) == TYPE_CODE_ARRAY)
015a42b4 JB	138	{
	139	/* Handle the case where the vtbl field points to an
	140	array of structures. */
	141	vtbl = value_ind (vtbl);
	142
	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);
	148	}
	149	else
	150	{
	151	/* Handle the case where the vtbl field points directly to a structure. */
89eef114	152	vtbl = value_ptradd (vtbl, vi);
015a42b4 JB	153	entry = value_ind (vtbl);
	154	}
	155
df407dfe	156	entry_type = check_typedef (value_type (entry));
015a42b4 JB	157
	158	if (TYPE_CODE (entry_type) == TYPE_CODE_STRUCT)
	159	{
	160	/* Move the `this' pointer according to the virtual function table. */
f5cf64a7	161	set_value_offset (arg1, value_offset (arg1) + value_as_long (value_field (entry, 0)));
015a42b4	162
d69fe07e	163	if (!value_lazy (arg1))
015a42b4	164	{
dfa52d88	165	set_value_lazy (arg1, 1);
015a42b4 JB	166	value_fetch_lazy (arg1);
	167	}
	168
	169	vfn = value_field (entry, 2);
	170	}
	171	else if (TYPE_CODE (entry_type) == TYPE_CODE_PTR)
	172	vfn = entry;
	173	else
8a3fe4f8	174	error (_("I'm confused: virtual function table has bad type"));
015a42b4	175	/* Reinstantiate the function pointer with the correct type. */
04624583	176	deprecated_set_value_type (vfn, lookup_pointer_type (TYPE_FN_FIELD_TYPE (f, j)));
015a42b4 JB	177
	178	*arg1p = arg1;
	179	return vfn;
	180	}
	181
	182
b9362cc7	183	static struct type *
e933e538	184	gnuv2_value_rtti_type (struct value v, int full, int top, int using_enc)
015a42b4 JB	185	{
	186	struct type *known_type;
	187	struct type *rtti_type;
	188	CORE_ADDR coreptr;
e933e538	189	struct value *vp;
015a42b4 JB	190	long top_offset = 0;
	191	char rtti_type_name[256];
	192	CORE_ADDR vtbl;
	193	struct minimal_symbol *minsym;
	194	struct symbol *sym;
7d63ec12	195	char demangled_name, p;
015a42b4	196	struct type *btype;
81fe8080 DE	197	struct type *known_type_vptr_basetype;
81fe8080 DE	198	int known_type_vptr_fieldno;
015a42b4 JB	199
	200	if (full)
	201	*full = 0;
	202	if (top)
	203	*top = -1;
	204	if (using_enc)
	205	*using_enc = 0;
	206
	207	/* Get declared type */
df407dfe	208	known_type = value_type (v);
015a42b4 JB	209	CHECK_TYPEDEF (known_type);
	210	/* RTTI works only or class objects */
	211	if (TYPE_CODE (known_type) != TYPE_CODE_CLASS)
	212	return NULL;
	213
	214	/* Plan on this changing in the future as i get around to setting
	215	the vtables properly for G++ compiled stuff. Also, I'll be using
	216	the type info functions, which are always right. Deal with it
	217	until then. */
	218
81fe8080 DE	219	/* Try to get the vptr basetype, fieldno. */
	220	known_type_vptr_fieldno = get_vptr_fieldno (known_type,
	221	&known_type_vptr_basetype);
015a42b4	222
81fe8080 DE	223	/* If we can't find it, give up. */
81fe8080 DE	224	if (known_type_vptr_fieldno < 0)
015a42b4 JB	225	return NULL;
	226
	227	/* Make sure our basetype and known type match, otherwise, cast
	228	so we can get at the vtable properly.
	229	*/
81fe8080	230	btype = known_type_vptr_basetype;
015a42b4 JB	231	CHECK_TYPEDEF (btype);
	232	if (btype != known_type )
	233	{
	234	v = value_cast (btype, v);
	235	if (using_enc)
	236	*using_enc=1;
	237	}
	238	/*
	239	We can't use value_ind here, because it would want to use RTTI, and
	240	we'd waste a bunch of time figuring out we already know the type.
	241	Besides, we don't care about the type, just the actual pointer
	242	*/
42ae5230	243	if (value_address (value_field (v, known_type_vptr_fieldno)) == 0)
015a42b4 JB	244	return NULL;
015a42b4 JB	245
81fe8080	246	vtbl = value_as_address (value_field (v, known_type_vptr_fieldno));
015a42b4 JB	247
	248	/* Try to find a symbol that is the vtable */
	249	minsym=lookup_minimal_symbol_by_pc(vtbl);
	250	if (minsym==NULL
3567439c	251	\|\| (demangled_name=SYMBOL_LINKAGE_NAME (minsym))==NULL
015a42b4 JB	252	\|\| !is_vtable_name (demangled_name))
	253	return NULL;
	254
	255	/* If we just skip the prefix, we get screwed by namespaces */
	256	demangled_name=cplus_demangle(demangled_name,DMGL_PARAMS\|DMGL_ANSI);
7d63ec12 MS	257	p = strchr (demangled_name, ' ');
	258	if (p)
	259	*p = '\0';
015a42b4 JB	260
015a42b4 JB	261	/* Lookup the type for the name */
362ff856 MC	262	/* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */
	263	rtti_type = cp_lookup_rtti_type (demangled_name, NULL);
	264	if (rtti_type == NULL)
015a42b4 JB	265	return NULL;
	266
	267	if (TYPE_N_BASECLASSES(rtti_type) > 1 && full && (*full) != 1)
	268	{
	269	if (top)
	270	*top=TYPE_BASECLASS_BITPOS(rtti_type,TYPE_VPTR_FIELDNO(rtti_type))/8;
	271	if (top && ((*top) >0))
	272	{
	273	if (TYPE_LENGTH(rtti_type) > TYPE_LENGTH(known_type))
	274	{
	275	if (full)
	276	*full=0;
	277	}
	278	else
	279	{
	280	if (full)
	281	*full=1;
	282	}
	283	}
	284	}
	285	else
	286	{
	287	if (full)
	288	*full=1;
	289	}
015a42b4 JB	290
	291	return rtti_type;
	292	}
	293
1514d34e DJ	294	/* Return true if the INDEXth field of TYPE is a virtual baseclass
	295	pointer which is for the base class whose type is BASECLASS. */
	296
	297	static int
	298	vb_match (struct type type, int index, struct type basetype)
	299	{
	300	struct type *fieldtype;
	301	char *name = TYPE_FIELD_NAME (type, index);
	302	char *field_class_name = NULL;
	303
	304	if (*name != '_')
	305	return 0;
	306	/* gcc 2.4 uses _vb$. */
	307	if (name[1] == 'v' && name[2] == 'b' && is_cplus_marker (name[3]))
	308	field_class_name = name + 4;
	309	/* gcc 2.5 will use __vb_. */
	310	if (name[1] == '_' && name[2] == 'v' && name[3] == 'b' && name[4] == '_')
	311	field_class_name = name + 5;
	312
	313	if (field_class_name == NULL)
	314	/* This field is not a virtual base class pointer. */
	315	return 0;
	316
	317	/* It's a virtual baseclass pointer, now we just need to find out whether
	318	it is for this baseclass. */
	319	fieldtype = TYPE_FIELD_TYPE (type, index);
	320	if (fieldtype == NULL
	321	\|\| TYPE_CODE (fieldtype) != TYPE_CODE_PTR)
	322	/* "Can't happen". */
	323	return 0;
	324
	325	/* What we check for is that either the types are equal (needed for
	326	nameless types) or have the same name. This is ugly, and a more
	327	elegant solution should be devised (which would probably just push
	328	the ugliness into symbol reading unless we change the stabs format). */
	329	if (TYPE_TARGET_TYPE (fieldtype) == basetype)
	330	return 1;
	331
	332	if (TYPE_NAME (basetype) != NULL
	333	&& TYPE_NAME (TYPE_TARGET_TYPE (fieldtype)) != NULL
bde58177 AC	334	&& strcmp (TYPE_NAME (basetype),
bde58177 AC	335	TYPE_NAME (TYPE_TARGET_TYPE (fieldtype))) == 0)
1514d34e DJ	336	return 1;
	337	return 0;
	338	}
	339
	340	/* Compute the offset of the baseclass which is
	341	the INDEXth baseclass of class TYPE,
	342	for value at VALADDR (in host) at ADDRESS (in target).
	343	The result is the offset of the baseclass value relative
	344	to (the address of)(ARG) + OFFSET.
	345
	346	-1 is returned on error. */
	347
f23f4c59	348	static int
06c4d4dc AC	349	gnuv2_baseclass_offset (struct type *type, int index,
06c4d4dc AC	350	const bfd_byte *valaddr, CORE_ADDR address)
1514d34e DJ	351	{
	352	struct type *basetype = TYPE_BASECLASS (type, index);
	353
	354	if (BASETYPE_VIA_VIRTUAL (type, index))
	355	{
	356	/* Must hunt for the pointer to this virtual baseclass. */
aa1ee363 AC	357	int i, len = TYPE_NFIELDS (type);
aa1ee363 AC	358	int n_baseclasses = TYPE_N_BASECLASSES (type);
1514d34e DJ	359
	360	/* First look for the virtual baseclass pointer
	361	in the fields. */
	362	for (i = n_baseclasses; i < len; i++)
	363	{
	364	if (vb_match (type, i, basetype))
	365	{
	366	CORE_ADDR addr
	367	= unpack_pointer (TYPE_FIELD_TYPE (type, i),
	368	valaddr + (TYPE_FIELD_BITPOS (type, i) / 8));
	369
	370	return addr - (LONGEST) address;
	371	}
	372	}
	373	/* Not in the fields, so try looking through the baseclasses. */
	374	for (i = index + 1; i < n_baseclasses; i++)
	375	{
	376	int boffset =
	377	baseclass_offset (type, i, valaddr, address);
	378	if (boffset)
	379	return boffset;
	380	}
	381	/* Not found. */
	382	return -1;
	383	}
	384
	385	/* Baseclass is easily computed. */
	386	return TYPE_BASECLASS_BITPOS (type, index) / 8;
	387	}
015a42b4 JB	388
	389	static void
	390	init_gnuv2_ops (void)
	391	{
	392	gnu_v2_abi_ops.shortname = "gnu-v2";
	393	gnu_v2_abi_ops.longname = "GNU G++ Version 2 ABI";
	394	gnu_v2_abi_ops.doc = "G++ Version 2 ABI";
	395	gnu_v2_abi_ops.is_destructor_name = gnuv2_is_destructor_name;
	396	gnu_v2_abi_ops.is_constructor_name = gnuv2_is_constructor_name;
	397	gnu_v2_abi_ops.is_vtable_name = gnuv2_is_vtable_name;
	398	gnu_v2_abi_ops.is_operator_name = gnuv2_is_operator_name;
	399	gnu_v2_abi_ops.virtual_fn_field = gnuv2_virtual_fn_field;
	400	gnu_v2_abi_ops.rtti_type = gnuv2_value_rtti_type;
1514d34e	401	gnu_v2_abi_ops.baseclass_offset = gnuv2_baseclass_offset;
015a42b4 JB	402	}
015a42b4 JB	403
b9362cc7 AC	404	extern initialize_file_ftype _initialize_gnu_v2_abi; /* -Wmissing-prototypes */
b9362cc7 AC	405
015a42b4 JB	406	void
	407	_initialize_gnu_v2_abi (void)
	408	{
	409	init_gnuv2_ops ();
fe1f4a5e DJ	410	register_cp_abi (&gnu_v2_abi_ops);
fe1f4a5e DJ	411	set_cp_abi_as_auto_default (gnu_v2_abi_ops.shortname);
015a42b4	412	}