Initial revision

1 files changed, 1623 insertions, 0 deletions

diff --git a/gdb/values.c b/gdb/values.c
new file mode 100644
index 00000000000..c7053b8df78
--- /dev/null
+++ b/gdb/values.c
@@ -0,0 +1,1623 @@
+/* Low level packing and unpacking of values for GDB, the GNU Debugger.
+   Copyright 1986, 87, 89, 91, 93, 94, 95, 96, 97, 1998
+   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 "gdbcore.h"
+#include "frame.h"
+#include "command.h"
+#include "gdbcmd.h"
+#include "target.h"
+#include "language.h"
+#include "scm-lang.h"
+#include "demangle.h"
+
+/* Prototypes for exported functions. */
+
+void _initialize_values PARAMS ((void));
+
+/* Prototypes for local functions. */
+
+static value_ptr value_headof PARAMS ((value_ptr, struct type *,
+				       struct type *));
+
+static void show_values PARAMS ((char *, int));
+
+static void show_convenience PARAMS ((char *, int));
+
+static int vb_match PARAMS ((struct type *, int, struct type *));
+
+/* The value-history records all the values printed
+   by print commands during this session.  Each chunk
+   records 60 consecutive values.  The first chunk on
+   the chain records the most recent values.
+   The total number of values is in value_history_count.  */
+
+#define VALUE_HISTORY_CHUNK 60
+
+struct value_history_chunk
+{
+  struct value_history_chunk *next;
+  value_ptr values[VALUE_HISTORY_CHUNK];
+};
+
+/* Chain of chunks now in use.  */
+
+static struct value_history_chunk *value_history_chain;
+
+static int value_history_count;	/* Abs number of last entry stored */
+
+/* List of all value objects currently allocated
+   (except for those released by calls to release_value)
+   This is so they can be freed after each command.  */
+
+static value_ptr all_values;
+
+/* Allocate a  value  that has the correct length for type TYPE.  */
+
+value_ptr
+allocate_value (type)
+     struct type *type;
+{
+  register value_ptr val;
+  struct type *atype = check_typedef (type);
+
+  val = (struct value *) xmalloc (sizeof (struct value) + TYPE_LENGTH (atype));
+  VALUE_NEXT (val) = all_values;
+  all_values = val;
+  VALUE_TYPE (val) = type;
+  VALUE_ENCLOSING_TYPE (val) = type;
+  VALUE_LVAL (val) = not_lval;
+  VALUE_ADDRESS (val) = 0;
+  VALUE_FRAME (val) = 0;
+  VALUE_OFFSET (val) = 0;
+  VALUE_BITPOS (val) = 0;
+  VALUE_BITSIZE (val) = 0;
+  VALUE_REGNO (val) = -1;
+  VALUE_LAZY (val) = 0;
+  VALUE_OPTIMIZED_OUT (val) = 0;
+  VALUE_BFD_SECTION (val) = NULL;
+  VALUE_EMBEDDED_OFFSET (val) = 0;
+  VALUE_POINTED_TO_OFFSET (val) = 0;
+  val->modifiable = 1;
+  return val;
+}
+
+/* Allocate a  value  that has the correct length
+   for COUNT repetitions type TYPE.  */
+
+value_ptr
+allocate_repeat_value (type, count)
+     struct type *type;
+     int count;
+{
+  int low_bound = current_language->string_lower_bound; /* ??? */
+  /* FIXME-type-allocation: need a way to free this type when we are
+     done with it.  */
+  struct type *range_type
+    = create_range_type ((struct type *) NULL, builtin_type_int,
+			 low_bound, count + low_bound - 1);
+  /* FIXME-type-allocation: need a way to free this type when we are
+     done with it.  */
+  return allocate_value (create_array_type ((struct type *) NULL,
+					    type, range_type));
+}
+
+/* Return a mark in the value chain.  All values allocated after the
+   mark is obtained (except for those released) are subject to being freed
+   if a subsequent value_free_to_mark is passed the mark.  */
+value_ptr
+value_mark ()
+{
+  return all_values;
+}
+
+/* Free all values allocated since MARK was obtained by value_mark
+   (except for those released).  */
+void
+value_free_to_mark (mark)
+     value_ptr mark;
+{
+  value_ptr val, next;
+
+  for (val = all_values; val && val != mark; val = next)
+    {
+      next = VALUE_NEXT (val);
+      value_free (val);
+    }
+  all_values = val;
+}
+
+/* Free all the values that have been allocated (except for those released).
+   Called after each command, successful or not.  */
+
+void
+free_all_values ()
+{
+  register value_ptr val, next;
+
+  for (val = all_values; val; val = next)
+    {
+      next = VALUE_NEXT (val);
+      value_free (val);
+    }
+
+  all_values = 0;
+}
+
+/* Remove VAL from the chain all_values
+   so it will not be freed automatically.  */
+
+void
+release_value (val)
+     register value_ptr val;
+{
+  register value_ptr v;
+
+  if (all_values == val)
+    {
+      all_values = val->next;
+      return;
+    }
+
+  for (v = all_values; v; v = v->next)
+    {
+      if (v->next == val)
+	{
+	  v->next = val->next;
+	  break;
+	}
+    }
+}
+
+/* Release all values up to mark  */
+value_ptr
+value_release_to_mark (mark)
+     value_ptr mark;
+{
+  value_ptr val, next;
+
+  for (val = next = all_values; next; next = VALUE_NEXT (next))
+    if (VALUE_NEXT (next) == mark)
+      {
+	all_values = VALUE_NEXT (next);
+	VALUE_NEXT (next) = 0;
+	return val;
+      }
+  all_values = 0;
+  return val;
+}
+
+/* Return a copy of the value ARG.
+   It contains the same contents, for same memory address,
+   but it's a different block of storage.  */
+
+value_ptr
+value_copy (arg)
+     value_ptr arg;
+{
+  register struct type *encl_type = VALUE_ENCLOSING_TYPE (arg);
+  register value_ptr val = allocate_value (encl_type);
+  VALUE_TYPE (val) = VALUE_TYPE (arg);
+  VALUE_LVAL (val) = VALUE_LVAL (arg);
+  VALUE_ADDRESS (val) = VALUE_ADDRESS (arg);
+  VALUE_OFFSET (val) = VALUE_OFFSET (arg);
+  VALUE_BITPOS (val) = VALUE_BITPOS (arg);
+  VALUE_BITSIZE (val) = VALUE_BITSIZE (arg);
+  VALUE_FRAME (val) = VALUE_FRAME (arg);
+  VALUE_REGNO (val) = VALUE_REGNO (arg);
+  VALUE_LAZY (val) = VALUE_LAZY (arg);
+  VALUE_OPTIMIZED_OUT (val) = VALUE_OPTIMIZED_OUT (arg);
+  VALUE_EMBEDDED_OFFSET (val) = VALUE_EMBEDDED_OFFSET (arg);
+  VALUE_POINTED_TO_OFFSET (val) = VALUE_POINTED_TO_OFFSET (arg);
+  VALUE_BFD_SECTION (val) = VALUE_BFD_SECTION (arg);
+  val->modifiable = arg->modifiable;
+  if (!VALUE_LAZY (val))
+    {
+      memcpy (VALUE_CONTENTS_ALL_RAW (val), VALUE_CONTENTS_ALL_RAW (arg),
+	      TYPE_LENGTH (VALUE_ENCLOSING_TYPE (arg)));
+
+    }
+  return val;
+}
+
+/* Access to the value history.  */
+
+/* Record a new value in the value history.
+   Returns the absolute history index of the entry.
+   Result of -1 indicates the value was not saved; otherwise it is the
+   value history index of this new item.  */
+
+int
+record_latest_value (val)
+     value_ptr val;
+{
+  int i;
+
+  /* We don't want this value to have anything to do with the inferior anymore.
+     In particular, "set $1 = 50" should not affect the variable from which
+     the value was taken, and fast watchpoints should be able to assume that
+     a value on the value history never changes.  */
+  if (VALUE_LAZY (val))
+    value_fetch_lazy (val);
+  /* We preserve VALUE_LVAL so that the user can find out where it was fetched
+     from.  This is a bit dubious, because then *&$1 does not just return $1
+     but the current contents of that location.  c'est la vie...  */
+  val->modifiable = 0;
+  release_value (val);
+
+  /* Here we treat value_history_count as origin-zero
+     and applying to the value being stored now.  */
+
+  i = value_history_count % VALUE_HISTORY_CHUNK;
+  if (i == 0)
+    {
+      register struct value_history_chunk *new
+	= (struct value_history_chunk *)
+	  xmalloc (sizeof (struct value_history_chunk));
+      memset (new->values, 0, sizeof new->values);
+      new->next = value_history_chain;
+      value_history_chain = new;
+    }
+
+  value_history_chain->values[i] = val;
+
+  /* Now we regard value_history_count as origin-one
+     and applying to the value just stored.  */
+
+  return ++value_history_count;
+}
+
+/* Return a copy of the value in the history with sequence number NUM.  */
+
+value_ptr
+access_value_history (num)
+     int num;
+{
+  register struct value_history_chunk *chunk;
+  register int i;
+  register int absnum = num;
+
+  if (absnum <= 0)
+    absnum += value_history_count;
+
+  if (absnum <= 0)
+    {
+      if (num == 0)
+	error ("The history is empty.");
+      else if (num == 1)
+	error ("There is only one value in the history.");
+      else
+	error ("History does not go back to $$%d.", -num);
+    }
+  if (absnum > value_history_count)
+    error ("History has not yet reached $%d.", absnum);
+
+  absnum--;
+
+  /* Now absnum is always absolute and origin zero.  */
+
+  chunk = value_history_chain;
+  for (i = (value_history_count - 1) / VALUE_HISTORY_CHUNK - absnum / VALUE_HISTORY_CHUNK;
+       i > 0; i--)
+    chunk = chunk->next;
+
+  return value_copy (chunk->values[absnum % VALUE_HISTORY_CHUNK]);
+}
+
+/* Clear the value history entirely.
+   Must be done when new symbol tables are loaded,
+   because the type pointers become invalid.  */
+
+void
+clear_value_history ()
+{
+  register struct value_history_chunk *next;
+  register int i;
+  register value_ptr val;
+
+  while (value_history_chain)
+    {
+      for (i = 0; i < VALUE_HISTORY_CHUNK; i++)
+	if ((val = value_history_chain->values[i]) != NULL)
+	  free ((PTR)val);
+      next = value_history_chain->next;
+      free ((PTR)value_history_chain);
+      value_history_chain = next;
+    }
+  value_history_count = 0;
+}
+
+static void
+show_values (num_exp, from_tty)
+     char *num_exp;
+     int from_tty;
+{
+  register int i;
+  register value_ptr val;
+  static int num = 1;
+
+  if (num_exp)
+    {
+	/* "info history +" should print from the stored position.
+	   "info history <exp>" should print around value number <exp>.  */
+      if (num_exp[0] != '+' || num_exp[1] != '\0')
+	num = parse_and_eval_address (num_exp) - 5;
+    }
+  else
+    {
+      /* "info history" means print the last 10 values.  */
+      num = value_history_count - 9;
+    }
+
+  if (num <= 0)
+    num = 1;
+
+  for (i = num; i < num + 10 && i <= value_history_count; i++)
+    {
+      val = access_value_history (i);
+      printf_filtered ("$%d = ", i);
+      value_print (val, gdb_stdout, 0, Val_pretty_default);
+      printf_filtered ("\n");
+    }
+
+  /* The next "info history +" should start after what we just printed.  */
+  num += 10;
+
+  /* Hitting just return after this command should do the same thing as
+     "info history +".  If num_exp is null, this is unnecessary, since
+     "info history +" is not useful after "info history".  */
+  if (from_tty && num_exp)
+    {
+      num_exp[0] = '+';
+      num_exp[1] = '\0';
+    }
+}
+
+/* Internal variables.  These are variables within the debugger
+   that hold values assigned by debugger commands.
+   The user refers to them with a '$' prefix
+   that does not appear in the variable names stored internally.  */
+
+static struct internalvar *internalvars;
+
+/* Look up an internal variable with name NAME.  NAME should not
+   normally include a dollar sign.
+
+   If the specified internal variable does not exist,
+   one is created, with a void value.  */
+
+struct internalvar *
+lookup_internalvar (name)
+     char *name;
+{
+  register struct internalvar *var;
+
+  for (var = internalvars; var; var = var->next)
+    if (STREQ (var->name, name))
+      return var;
+
+  var = (struct internalvar *) xmalloc (sizeof (struct internalvar));
+  var->name = concat (name, NULL);
+  var->value = allocate_value (builtin_type_void);
+  release_value (var->value);
+  var->next = internalvars;
+  internalvars = var;
+  return var;
+}
+
+value_ptr
+value_of_internalvar (var)
+     struct internalvar *var;
+{
+  register value_ptr val;
+
+#ifdef IS_TRAPPED_INTERNALVAR
+  if (IS_TRAPPED_INTERNALVAR (var->name))
+    return VALUE_OF_TRAPPED_INTERNALVAR (var);
+#endif 
+
+  val = value_copy (var->value);
+  if (VALUE_LAZY (val))
+    value_fetch_lazy (val);
+  VALUE_LVAL (val) = lval_internalvar;
+  VALUE_INTERNALVAR (val) = var;
+  return val;
+}
+
+void
+set_internalvar_component (var, offset, bitpos, bitsize, newval)
+     struct internalvar *var;
+     int offset, bitpos, bitsize;
+     value_ptr newval;
+{
+  register char *addr = VALUE_CONTENTS (var->value) + offset;
+
+#ifdef IS_TRAPPED_INTERNALVAR
+  if (IS_TRAPPED_INTERNALVAR (var->name))
+    SET_TRAPPED_INTERNALVAR (var, newval, bitpos, bitsize, offset);
+#endif
+
+  if (bitsize)
+    modify_field (addr, value_as_long (newval),
+		  bitpos, bitsize);
+  else
+    memcpy (addr, VALUE_CONTENTS (newval), TYPE_LENGTH (VALUE_TYPE (newval)));
+}
+
+void
+set_internalvar (var, val)
+     struct internalvar *var;
+     value_ptr val;
+{
+  value_ptr newval;
+
+#ifdef IS_TRAPPED_INTERNALVAR
+  if (IS_TRAPPED_INTERNALVAR (var->name))
+    SET_TRAPPED_INTERNALVAR (var, val, 0, 0, 0);
+#endif
+
+  newval = value_copy (val);
+  newval->modifiable = 1;
+
+  /* Force the value to be fetched from the target now, to avoid problems
+     later when this internalvar is referenced and the target is gone or
+     has changed.  */
+  if (VALUE_LAZY (newval))
+    value_fetch_lazy (newval);
+
+  /* Begin code which must not call error().  If var->value points to
+     something free'd, an error() obviously leaves a dangling pointer.
+     But we also get a danling pointer if var->value points to
+     something in the value chain (i.e., before release_value is
+     called), because after the error free_all_values will get called before
+     long.  */
+  free ((PTR)var->value);
+  var->value = newval;
+  release_value (newval);
+  /* End code which must not call error().  */
+}
+
+char *
+internalvar_name (var)
+     struct internalvar *var;
+{
+  return var->name;
+}
+
+/* Free all internalvars.  Done when new symtabs are loaded,
+   because that makes the values invalid.  */
+
+void
+clear_internalvars ()
+{
+  register struct internalvar *var;
+
+  while (internalvars)
+    {
+      var = internalvars;
+      internalvars = var->next;
+      free ((PTR)var->name);
+      free ((PTR)var->value);
+      free ((PTR)var);
+    }
+}
+
+static void
+show_convenience (ignore, from_tty)
+     char *ignore;
+     int from_tty;
+{
+  register struct internalvar *var;
+  int varseen = 0;
+
+  for (var = internalvars; var; var = var->next)
+    {
+#ifdef IS_TRAPPED_INTERNALVAR
+      if (IS_TRAPPED_INTERNALVAR (var->name))
+	continue;
+#endif
+      if (!varseen)
+	{
+	  varseen = 1;
+	}
+      printf_filtered ("$%s = ", var->name);
+      value_print (var->value, gdb_stdout, 0, Val_pretty_default);
+      printf_filtered ("\n");
+    }
+  if (!varseen)
+    printf_unfiltered ("No debugger convenience variables now defined.\n\
+Convenience variables have names starting with \"$\";\n\
+use \"set\" as in \"set $foo = 5\" to define them.\n");
+}
+
+/* Extract a value as a C number (either long or double).
+   Knows how to convert fixed values to double, or
+   floating values to long.
+   Does not deallocate the value.  */
+
+LONGEST
+value_as_long (val)
+     register value_ptr val;
+{
+  /* This coerces arrays and functions, which is necessary (e.g.
+     in disassemble_command).  It also dereferences references, which
+     I suspect is the most logical thing to do.  */
+  COERCE_ARRAY (val);
+  return unpack_long (VALUE_TYPE (val), VALUE_CONTENTS (val));
+}
+
+DOUBLEST
+value_as_double (val)
+     register value_ptr val;
+{
+  DOUBLEST foo;
+  int inv;
+  
+  foo = unpack_double (VALUE_TYPE (val), VALUE_CONTENTS (val), &inv);
+  if (inv)
+    error ("Invalid floating value found in program.");
+  return foo;
+}
+/* Extract a value as a C pointer.
+   Does not deallocate the value.  */
+CORE_ADDR
+value_as_pointer (val)
+     value_ptr val;
+{
+  /* Assume a CORE_ADDR can fit in a LONGEST (for now).  Not sure
+     whether we want this to be true eventually.  */
+#if 0
+  /* ADDR_BITS_REMOVE is wrong if we are being called for a
+     non-address (e.g. argument to "signal", "info break", etc.), or
+     for pointers to char, in which the low bits *are* significant.  */
+  return ADDR_BITS_REMOVE(value_as_long (val));
+#else
+  return value_as_long (val);
+#endif
+}
+
+/* Unpack raw data (copied from debugee, target byte order) at VALADDR
+   as a long, or as a double, assuming the raw data is described
+   by type TYPE.  Knows how to convert different sizes of values
+   and can convert between fixed and floating point.  We don't assume
+   any alignment for the raw data.  Return value is in host byte order.
+
+   If you want functions and arrays to be coerced to pointers, and
+   references to be dereferenced, call value_as_long() instead.
+
+   C++: It is assumed that the front-end has taken care of
+   all matters concerning pointers to members.  A pointer
+   to member which reaches here is considered to be equivalent
+   to an INT (or some size).  After all, it is only an offset.  */
+
+LONGEST
+unpack_long (type, valaddr)
+     struct type *type;
+     char *valaddr;
+{
+  register enum type_code code = TYPE_CODE (type);
+  register int len = TYPE_LENGTH (type);
+  register int nosign = TYPE_UNSIGNED (type);
+
+  if (current_language->la_language == language_scm
+      && is_scmvalue_type (type))
+    return scm_unpack (type, valaddr, TYPE_CODE_INT);
+
+  switch (code)
+    {
+    case TYPE_CODE_TYPEDEF:
+      return unpack_long (check_typedef (type), valaddr);
+    case TYPE_CODE_ENUM:
+    case TYPE_CODE_BOOL:
+    case TYPE_CODE_INT:
+    case TYPE_CODE_CHAR:
+    case TYPE_CODE_RANGE:
+      if (nosign)
+	return extract_unsigned_integer (valaddr, len);
+      else
+	return extract_signed_integer (valaddr, len);
+
+    case TYPE_CODE_FLT:
+      return extract_floating (valaddr, len);
+
+    case TYPE_CODE_PTR:
+    case TYPE_CODE_REF:
+      /* Assume a CORE_ADDR can fit in a LONGEST (for now).  Not sure
+	 whether we want this to be true eventually.  */
+#ifdef GDB_TARGET_IS_D10V
+      if (len == 2)
+	  return D10V_MAKE_DADDR(extract_address (valaddr, len));
+#endif
+      return extract_address (valaddr, len);
+
+    case TYPE_CODE_MEMBER:
+      error ("not implemented: member types in unpack_long");
+
+    default:
+      error ("Value can't be converted to integer.");
+    }
+  return 0; /* Placate lint.  */
+}
+
+/* Return a double value from the specified type and address.
+   INVP points to an int which is set to 0 for valid value,
+   1 for invalid value (bad float format).  In either case,
+   the returned double is OK to use.  Argument is in target
+   format, result is in host format.  */
+
+DOUBLEST
+unpack_double (type, valaddr, invp)
+     struct type *type;
+     char *valaddr;
+     int *invp;
+{
+  enum type_code code;
+  int len;
+  int nosign;
+
+  *invp = 0;			/* Assume valid.   */
+  CHECK_TYPEDEF (type);
+  code = TYPE_CODE (type);
+  len = TYPE_LENGTH (type);
+  nosign = TYPE_UNSIGNED (type);
+  if (code == TYPE_CODE_FLT)
+    {
+#ifdef INVALID_FLOAT
+      if (INVALID_FLOAT (valaddr, len))
+	{
+	  *invp = 1;
+	  return 1.234567891011121314;
+	}
+#endif
+      return extract_floating (valaddr, len);
+    }
+  else if (nosign)
+    {
+      /* Unsigned -- be sure we compensate for signed LONGEST.  */
+#if !defined (_MSC_VER) || (_MSC_VER > 900)
+      return (ULONGEST) unpack_long (type, valaddr);
+#else
+      /* FIXME!!! msvc22 doesn't support unsigned __int64 -> double */
+      return (LONGEST) unpack_long (type, valaddr);
+#endif /* _MSC_VER */
+    }
+  else
+    {
+      /* Signed -- we are OK with unpack_long.  */
+      return unpack_long (type, valaddr);
+    }
+}
+
+/* Unpack raw data (copied from debugee, target byte order) at VALADDR
+   as a CORE_ADDR, assuming the raw data is described by type TYPE.
+   We don't assume any alignment for the raw data.  Return value is in
+   host byte order.
+
+   If you want functions and arrays to be coerced to pointers, and
+   references to be dereferenced, call value_as_pointer() instead.
+
+   C++: It is assumed that the front-end has taken care of
+   all matters concerning pointers to members.  A pointer
+   to member which reaches here is considered to be equivalent
+   to an INT (or some size).  After all, it is only an offset.  */
+
+CORE_ADDR
+unpack_pointer (type, valaddr)
+     struct type *type;
+     char *valaddr;
+{
+  /* Assume a CORE_ADDR can fit in a LONGEST (for now).  Not sure
+     whether we want this to be true eventually.  */
+  return unpack_long (type, valaddr);
+}
+
+/* Get the value of the FIELDN'th field (which must be static) of TYPE. */
+
+value_ptr
+value_static_field (type, fieldno)
+     struct type *type;
+     int fieldno;
+{
+  CORE_ADDR addr;
+  asection *sect;
+  if (TYPE_FIELD_STATIC_HAS_ADDR (type, fieldno))
+    {
+      addr = TYPE_FIELD_STATIC_PHYSADDR (type, fieldno);
+      sect = NULL;
+    }
+  else
+    {
+      char *phys_name = TYPE_FIELD_STATIC_PHYSNAME (type, fieldno);
+      struct symbol *sym = lookup_symbol (phys_name, 0, VAR_NAMESPACE, 0, NULL);
+      if (sym == NULL)
+	{
+	  /* With some compilers, e.g. HP aCC, static data members are reported
+	     as non-debuggable symbols */ 
+	  struct minimal_symbol * msym = lookup_minimal_symbol (phys_name, NULL, NULL);
+	  if (!msym)
+	    return NULL;
+	  else
+	    {     
+	      addr = SYMBOL_VALUE_ADDRESS (msym);
+	      sect = SYMBOL_BFD_SECTION (msym);
+	    }
+	}
+      else
+	{
+	  addr = SYMBOL_VALUE_ADDRESS (sym);
+	  sect = SYMBOL_BFD_SECTION (sym);
+	}
+      SET_FIELD_PHYSADDR (TYPE_FIELD (type, fieldno), addr);
+    }
+  return value_at (TYPE_FIELD_TYPE (type, fieldno), addr, sect);
+}
+
+/* Given a value ARG1 (offset by OFFSET bytes)
+   of a struct or union type ARG_TYPE,
+   extract and return the value of one of its (non-static) fields.
+   FIELDNO says which field. */
+
+value_ptr
+value_primitive_field (arg1, offset, fieldno, arg_type)
+     register value_ptr arg1;
+     int offset;
+     register int fieldno;
+     register struct type *arg_type;
+{
+  register value_ptr v;
+  register struct type *type;
+
+  CHECK_TYPEDEF (arg_type);
+  type = TYPE_FIELD_TYPE (arg_type, fieldno);
+
+  /* Handle packed fields */
+
+  if (TYPE_FIELD_BITSIZE (arg_type, fieldno))
+    {
+      v = value_from_longest (type,
+			      unpack_field_as_long (arg_type,
+						    VALUE_CONTENTS (arg1)
+						      + offset,
+						    fieldno));
+      VALUE_BITPOS (v) = TYPE_FIELD_BITPOS (arg_type, fieldno) % 8;
+      VALUE_BITSIZE (v) = TYPE_FIELD_BITSIZE (arg_type, fieldno);
+    }
+  else if (fieldno < TYPE_N_BASECLASSES (arg_type))
+    {
+      /* This field is actually a base subobject, so preserve the
+         entire object's contents for later references to virtual
+         bases, etc.  */
+      v = allocate_value (VALUE_ENCLOSING_TYPE (arg1));
+      VALUE_TYPE (v) = arg_type;
+      if (VALUE_LAZY (arg1))
+	VALUE_LAZY (v) = 1;
+      else
+	memcpy (VALUE_CONTENTS_ALL_RAW (v), VALUE_CONTENTS_ALL_RAW (arg1),
+		TYPE_LENGTH (VALUE_ENCLOSING_TYPE (arg1)));
+      VALUE_OFFSET (v) = VALUE_OFFSET (arg1);
+      VALUE_EMBEDDED_OFFSET (v)
+        = offset + 
+          VALUE_EMBEDDED_OFFSET (arg1) + 
+          TYPE_FIELD_BITPOS (arg_type, fieldno) / 8;
+    }
+  else
+    {
+      /* Plain old data member */
+      offset += TYPE_FIELD_BITPOS (arg_type, fieldno) / 8;
+      v = allocate_value (type);
+      if (VALUE_LAZY (arg1))
+	VALUE_LAZY (v) = 1;
+      else
+	memcpy (VALUE_CONTENTS_RAW (v),
+		VALUE_CONTENTS_RAW (arg1) + offset,
+		TYPE_LENGTH (type));
+      VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset;
+    }
+  VALUE_LVAL (v) = VALUE_LVAL (arg1);
+  if (VALUE_LVAL (arg1) == lval_internalvar)
+    VALUE_LVAL (v) = lval_internalvar_component;
+  VALUE_ADDRESS (v) = VALUE_ADDRESS (arg1);
+/*  VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset
+		     + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; */
+  return v;
+}
+
+/* Given a value ARG1 of a struct or union type,
+   extract and return the value of one of its (non-static) fields.
+   FIELDNO says which field. */
+
+value_ptr
+value_field (arg1, fieldno)
+     register value_ptr arg1;
+     register int fieldno;
+{
+  return value_primitive_field (arg1, 0, fieldno, VALUE_TYPE (arg1));
+}
+
+/* Return a non-virtual function as a value.
+   F is the list of member functions which contains the desired method.
+   J is an index into F which provides the desired method. */
+
+value_ptr
+value_fn_field (arg1p, f, j, type, offset)
+     value_ptr *arg1p;
+     struct fn_field *f;
+     int j;
+     struct type *type;
+     int offset;
+{
+  register value_ptr v;
+  register struct type *ftype = TYPE_FN_FIELD_TYPE (f, j);
+  struct symbol *sym;
+
+  sym = lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f, j),
+		       0, VAR_NAMESPACE, 0, NULL);
+  if (! sym) 
+	return NULL;
+/*
+	error ("Internal error: could not find physical method named %s",
+		    TYPE_FN_FIELD_PHYSNAME (f, j));
+*/
+  
+  v = allocate_value (ftype);
+  VALUE_ADDRESS (v) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym));
+  VALUE_TYPE (v) = ftype;
+
+  if (arg1p)
+   {
+    if (type != VALUE_TYPE (*arg1p))
+      *arg1p = value_ind (value_cast (lookup_pointer_type (type),
+				      value_addr (*arg1p)));
+
+    /* Move the `this' pointer according to the offset. 
+    VALUE_OFFSET (*arg1p) += offset;
+    */
+    }
+
+  return v;
+}
+
+/* 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.  */
+value_ptr
+value_virtual_fn_field (arg1p, f, j, type, offset)
+     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));
+
+  if (TYPE_HAS_VTABLE (type))
+    {
+      /* Deal with HP/Taligent runtime model for virtual functions */
+      value_ptr vp;
+      value_ptr argp;        /* arg1 cast to base */
+      CORE_ADDR vfunc_addr;  /* address of virtual method */
+      CORE_ADDR coreptr;     /* pointer to target address */ 
+      int class_index;       /* which class segment pointer to use */
+      struct type * ftype = TYPE_FN_FIELD_TYPE (f, j);   /* method type */
+
+      argp = value_cast (type, *arg1p);
+
+      if (VALUE_ADDRESS (argp) == 0)
+        error ("Address of object is null; object may not have been created.");
+      
+      /* pai: FIXME -- 32x64 possible problem? */
+      /* First word (4 bytes) in object layout is the vtable pointer */
+      coreptr = * (CORE_ADDR *) (VALUE_CONTENTS (argp)); /* pai: (temp)  */
+                                 /* + offset + VALUE_EMBEDDED_OFFSET (argp)); */ 
+
+      if (!coreptr)
+        error ("Virtual table pointer is null for object; object may not have been created.");
+      
+      /* pai/1997-05-09
+       * FIXME: The code here currently handles only
+       * the non-RRBC case of the Taligent/HP runtime spec; when RRBC
+       * is introduced, the condition for the "if" below will have to
+       * be changed to be a test for the RRBC case.  */
+       
+      if (1)
+        {
+          /* Non-RRBC case; the virtual function pointers are stored at fixed
+           * offsets in the virtual table. */
+
+          /* Retrieve the offset in the virtual table from the debug
+           * info.  The offset of the vfunc's entry is in words from
+           * the beginning of the vtable; but first we have to adjust
+           * by HP_ACC_VFUNC_START to account for other entries */
+          
+          /* pai: FIXME: 32x64 problem here, a word may be 8 bytes in
+           * which case the multiplier should be 8 and values should be long */
+          vp = value_at (builtin_type_int,
+                         coreptr + 4 * (TYPE_FN_FIELD_VOFFSET (f, j) + HP_ACC_VFUNC_START), NULL);
+          
+          coreptr = * (CORE_ADDR *) (VALUE_CONTENTS (vp));
+          /* coreptr now contains the address of the virtual function */
+          /* (Actually, it contains the pointer to the plabel for the function. */
+        }
+      else
+        {
+          /* RRBC case; the virtual function pointers are found by double
+           * indirection through the class segment tables. */
+          
+          /* Choose class segment depending on type we were passed */ 
+          class_index = class_index_in_primary_list (type);
+      
+          /* Find class segment pointer.  These are in the vtable slots after
+           * some other entries, so adjust by HP_ACC_VFUNC_START for that. */
+          /* pai: FIXME 32x64 problem here, if words are 8 bytes long
+           * the multiplier below has to be 8 and value should be long. */
+          vp = value_at (builtin_type_int,
+                         coreptr + 4 * (HP_ACC_VFUNC_START + class_index), NULL);
+          /* Indirect once more, offset by function index */
+          /* pai: FIXME 32x64 problem here, again multiplier could be 8 and value long */
+          coreptr = * (CORE_ADDR *) (VALUE_CONTENTS (vp) + 4 * TYPE_FN_FIELD_VOFFSET (f, j));
+          vp = value_at (builtin_type_int, coreptr, NULL);
+          coreptr = * (CORE_ADDR *) (VALUE_CONTENTS (vp));
+          
+          /* coreptr now contains the address of the virtual function */
+          /* (Actually, it contains the pointer to the plabel for the function.) */
+          
+        }
+
+      if (!coreptr)
+        error ("Address of virtual function is null; error in virtual table?");
+
+      /* Wrap this addr in a value and return pointer */ 
+      vp = allocate_value (ftype);
+      VALUE_TYPE (vp) = ftype;
+      VALUE_ADDRESS (vp) = coreptr;
+      
+      /* pai: (temp) do we need the value_ind stuff in value_fn_field? */
+      return vp;
+    }
+  else  
+    { /* Not using HP/Taligent runtime conventions; so try to
+       * use g++ conventions for virtual table */
+      
+      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;
+    }
+}
+
+/* ARG is a pointer to an object we know to be at least
+   a DTYPE.  BTYPE is the most derived basetype that has
+   already been searched (and need not be searched again).
+   After looking at the vtables between BTYPE and DTYPE,
+   return the most derived type we find.  The caller must
+   be satisfied when the return value == DTYPE.
+
+   FIXME-tiemann: should work with dossier entries as well.  */
+
+static value_ptr
+value_headof (in_arg, btype, dtype)
+     value_ptr in_arg;
+     struct type *btype, *dtype;
+{
+  /* First collect the vtables we must look at for this object.  */
+  /* FIXME-tiemann: right now, just look at top-most vtable.  */
+  value_ptr arg, vtbl, entry, best_entry = 0;
+  int i, nelems;
+  int offset, best_offset = 0;
+  struct symbol *sym;
+  CORE_ADDR pc_for_sym;
+  char *demangled_name;
+  struct minimal_symbol *msymbol;
+
+  btype = TYPE_VPTR_BASETYPE (dtype);
+  CHECK_TYPEDEF (btype);
+  arg = in_arg;
+  if (btype != dtype)
+    arg = value_cast (lookup_pointer_type (btype), arg);
+  vtbl = value_ind (value_field (value_ind (arg), TYPE_VPTR_FIELDNO (btype)));
+
+  /* Check that VTBL looks like it points to a virtual function table.  */
+  msymbol = lookup_minimal_symbol_by_pc (VALUE_ADDRESS (vtbl));
+  if (msymbol == NULL
+      || (demangled_name = SYMBOL_NAME (msymbol)) == NULL
+      || !VTBL_PREFIX_P (demangled_name))
+    {
+      /* If we expected to find a vtable, but did not, let the user
+	 know that we aren't happy, but don't throw an error.
+	 FIXME: there has to be a better way to do this.  */
+      struct type *error_type = (struct type *)xmalloc (sizeof (struct type));
+      memcpy (error_type, VALUE_TYPE (in_arg), sizeof (struct type));
+      TYPE_NAME (error_type) = savestring ("suspicious *", sizeof ("suspicious *"));
+      VALUE_TYPE (in_arg) = error_type;
+      return in_arg;
+    }
+
+  /* Now search through the virtual function table.  */
+  entry = value_ind (vtbl);
+  nelems = longest_to_int (value_as_long (value_field (entry, 2)));
+  for (i = 1; i <= nelems; i++)
+    {
+      entry = value_subscript (vtbl, value_from_longest (builtin_type_int, 
+						      (LONGEST) i));
+      /* This won't work if we're using thunks. */
+      if (TYPE_CODE (check_typedef (VALUE_TYPE (entry))) != TYPE_CODE_STRUCT)
+	break;
+      offset = longest_to_int (value_as_long (value_field (entry, 0)));
+      /* If we use '<=' we can handle single inheritance
+       * where all offsets are zero - just use the first entry found. */
+      if (offset <= best_offset)
+	{
+	  best_offset = offset;
+	  best_entry = entry;
+	}
+    }
+  /* Move the pointer according to BEST_ENTRY's offset, and figure
+     out what type we should return as the new pointer.  */
+  if (best_entry == 0)
+    {
+      /* An alternative method (which should no longer be necessary).
+       * But we leave it in for future use, when we will hopefully
+       * have optimizes the vtable to use thunks instead of offsets. */
+      /* Use the name of vtable itself to extract a base type. */
+      demangled_name += 4;  /* Skip _vt$ prefix. */
+    }
+  else
+    {
+      pc_for_sym = value_as_pointer (value_field (best_entry, 2));
+      sym = find_pc_function (pc_for_sym);
+      demangled_name = cplus_demangle (SYMBOL_NAME (sym), DMGL_ANSI);
+      *(strchr (demangled_name, ':')) = '\0';
+    }
+  sym = lookup_symbol (demangled_name, 0, VAR_NAMESPACE, 0, 0);
+  if (sym == NULL)
+    error ("could not find type declaration for `%s'", demangled_name);
+  if (best_entry)
+    {
+      free (demangled_name);
+      arg = value_add (value_cast (builtin_type_int, arg),
+		       value_field (best_entry, 0));
+    }
+  else arg = in_arg;
+  VALUE_TYPE (arg) = lookup_pointer_type (SYMBOL_TYPE (sym));
+  return arg;
+}
+
+/* ARG is a pointer object of type TYPE.  If TYPE has virtual
+   function tables, probe ARG's tables (including the vtables
+   of its baseclasses) to figure out the most derived type that ARG
+   could actually be a pointer to.  */
+
+value_ptr
+value_from_vtable_info (arg, type)
+     value_ptr arg;
+     struct type *type;
+{
+  /* Take care of preliminaries.  */
+  if (TYPE_VPTR_FIELDNO (type) < 0)
+    fill_in_vptr_fieldno (type);
+  if (TYPE_VPTR_FIELDNO (type) < 0)
+    return 0;
+
+  return value_headof (arg, 0, 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 (type, index, basetype)
+     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
+      && STREQ (TYPE_NAME (basetype),
+		TYPE_NAME (TYPE_TARGET_TYPE (fieldtype))))
+    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
+baseclass_offset (type, index, valaddr, address)
+     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.  */
+      register int i, len = TYPE_NFIELDS (type);
+      register 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;
+}
+
+/* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
+   VALADDR.
+
+   Extracting bits depends on endianness of the machine.  Compute the
+   number of least significant bits to discard.  For big endian machines,
+   we compute the total number of bits in the anonymous object, subtract
+   off the bit count from the MSB of the object to the MSB of the
+   bitfield, then the size of the bitfield, which leaves the LSB discard
+   count.  For little endian machines, the discard count is simply the
+   number of bits from the LSB of the anonymous object to the LSB of the
+   bitfield.
+
+   If the field is signed, we also do sign extension. */
+
+LONGEST
+unpack_field_as_long (type, valaddr, fieldno)
+     struct type *type;
+     char *valaddr;
+     int fieldno;
+{
+  ULONGEST val;
+  ULONGEST valmask;
+  int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
+  int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
+  int lsbcount;
+  struct type *field_type;
+
+  val = extract_unsigned_integer (valaddr + bitpos / 8, sizeof (val));
+  field_type = TYPE_FIELD_TYPE (type, fieldno);
+  CHECK_TYPEDEF (field_type);
+
+  /* Extract bits.  See comment above. */
+
+  if (BITS_BIG_ENDIAN)
+    lsbcount = (sizeof val * 8 - bitpos % 8 - bitsize);
+  else
+    lsbcount = (bitpos % 8);
+  val >>= lsbcount;
+
+  /* If the field does not entirely fill a LONGEST, then zero the sign bits.
+     If the field is signed, and is negative, then sign extend. */
+
+  if ((bitsize > 0) && (bitsize < 8 * (int) sizeof (val)))
+    {
+      valmask = (((ULONGEST) 1) << bitsize) - 1;
+      val &= valmask;
+      if (!TYPE_UNSIGNED (field_type))
+	{
+	  if (val & (valmask ^ (valmask >> 1)))
+	    {
+	      val |= ~valmask;
+	    }
+	}
+    }
+  return (val);
+}
+
+/* Modify the value of a bitfield.  ADDR points to a block of memory in
+   target byte order; the bitfield starts in the byte pointed to.  FIELDVAL
+   is the desired value of the field, in host byte order.  BITPOS and BITSIZE
+   indicate which bits (in target bit order) comprise the bitfield.  */
+
+void
+modify_field (addr, fieldval, bitpos, bitsize)
+     char *addr;
+     LONGEST fieldval;
+     int bitpos, bitsize;
+{
+  LONGEST oword;
+
+  /* If a negative fieldval fits in the field in question, chop
+     off the sign extension bits.  */
+  if (bitsize < (8 * (int) sizeof (fieldval))
+      && (~fieldval & ~((1 << (bitsize - 1)) - 1)) == 0)
+    fieldval = fieldval & ((1 << bitsize) - 1);
+
+  /* Warn if value is too big to fit in the field in question.  */
+  if (bitsize < (8 * (int) sizeof (fieldval))
+      && 0 != (fieldval & ~((1<<bitsize)-1)))
+    {
+      /* FIXME: would like to include fieldval in the message, but
+	 we don't have a sprintf_longest.  */
+      warning ("Value does not fit in %d bits.", bitsize);
+
+      /* Truncate it, otherwise adjoining fields may be corrupted.  */
+      fieldval = fieldval & ((1 << bitsize) - 1);
+    }
+
+  oword = extract_signed_integer (addr, sizeof oword);
+
+  /* Shifting for bit field depends on endianness of the target machine.  */
+  if (BITS_BIG_ENDIAN)
+    bitpos = sizeof (oword) * 8 - bitpos - bitsize;
+
+  /* Mask out old value, while avoiding shifts >= size of oword */
+  if (bitsize < 8 * (int) sizeof (oword))
+    oword &= ~(((((ULONGEST)1) << bitsize) - 1) << bitpos);
+  else
+    oword &= ~((~(ULONGEST)0) << bitpos);
+  oword |= fieldval << bitpos;
+
+  store_signed_integer (addr, sizeof oword, oword);
+}
+
+/* Convert C numbers into newly allocated values */
+
+value_ptr
+value_from_longest (type, num)
+     struct type *type;
+     register LONGEST num;
+{
+  register value_ptr val = allocate_value (type);
+  register enum type_code code;
+  register int len;
+ retry:
+  code = TYPE_CODE (type);
+  len = TYPE_LENGTH (type);
+
+  switch (code)
+    {
+    case TYPE_CODE_TYPEDEF:
+      type = check_typedef (type);
+      goto retry;
+    case TYPE_CODE_INT:
+    case TYPE_CODE_CHAR:
+    case TYPE_CODE_ENUM:
+    case TYPE_CODE_BOOL:
+    case TYPE_CODE_RANGE:
+      store_signed_integer (VALUE_CONTENTS_RAW (val), len, num);
+      break;
+      
+    case TYPE_CODE_REF:
+    case TYPE_CODE_PTR:
+      /* This assumes that all pointers of a given length
+	 have the same form.  */
+      store_address (VALUE_CONTENTS_RAW (val), len, (CORE_ADDR) num);
+      break;
+      
+    default:
+      error ("Unexpected type (%d) encountered for integer constant.", code);
+    }
+  return val;
+}
+
+value_ptr
+value_from_double (type, num)
+     struct type *type;
+     DOUBLEST num;
+{
+  register value_ptr val = allocate_value (type);
+  struct type *base_type = check_typedef (type);
+  register enum type_code code = TYPE_CODE (base_type);
+  register int len = TYPE_LENGTH (base_type);
+
+  if (code == TYPE_CODE_FLT)
+    {
+      store_floating (VALUE_CONTENTS_RAW (val), len, num);
+    }
+  else
+    error ("Unexpected type encountered for floating constant.");
+
+  return val;
+}
+
+/* Deal with the value that is "about to be returned".  */
+
+/* Return the value that a function returning now
+   would be returning to its caller, assuming its type is VALTYPE.
+   RETBUF is where we look for what ought to be the contents
+   of the registers (in raw form).  This is because it is often
+   desirable to restore old values to those registers
+   after saving the contents of interest, and then call
+   this function using the saved values.
+   struct_return is non-zero when the function in question is
+   using the structure return conventions on the machine in question;
+   0 when it is using the value returning conventions (this often
+   means returning pointer to where structure is vs. returning value). */
+
+value_ptr
+value_being_returned (valtype, retbuf, struct_return)
+     register struct type *valtype;
+     char retbuf[REGISTER_BYTES];
+     int struct_return;
+     /*ARGSUSED*/
+{
+  register value_ptr val;
+  CORE_ADDR addr;
+
+#if defined (EXTRACT_STRUCT_VALUE_ADDRESS)
+  /* If this is not defined, just use EXTRACT_RETURN_VALUE instead.  */
+  if (struct_return) {
+    addr = EXTRACT_STRUCT_VALUE_ADDRESS (retbuf);
+    if (!addr)
+      error ("Function return value unknown");
+    return value_at (valtype, addr, NULL);
+  }
+#endif
+
+  val = allocate_value (valtype);
+  CHECK_TYPEDEF (valtype);
+  EXTRACT_RETURN_VALUE (valtype, retbuf, VALUE_CONTENTS_RAW (val));
+
+  return val;
+}
+
+/* Should we use EXTRACT_STRUCT_VALUE_ADDRESS instead of
+   EXTRACT_RETURN_VALUE?  GCC_P is true if compiled with gcc
+   and TYPE is the type (which is known to be struct, union or array).
+
+   On most machines, the struct convention is used unless we are
+   using gcc and the type is of a special size.  */
+/* As of about 31 Mar 93, GCC was changed to be compatible with the
+   native compiler.  GCC 2.3.3 was the last release that did it the
+   old way.  Since gcc2_compiled was not changed, we have no
+   way to correctly win in all cases, so we just do the right thing
+   for gcc1 and for gcc2 after this change.  Thus it loses for gcc
+   2.0-2.3.3.  This is somewhat unfortunate, but changing gcc2_compiled
+   would cause more chaos than dealing with some struct returns being
+   handled wrong.  */
+
+int
+generic_use_struct_convention (gcc_p, value_type)
+     int gcc_p;
+     struct type *value_type;
+{     
+  return !((gcc_p == 1)
+	    && (TYPE_LENGTH (value_type) == 1
+		|| TYPE_LENGTH (value_type) == 2
+		|| TYPE_LENGTH (value_type) == 4
+		|| TYPE_LENGTH (value_type) == 8));
+}
+
+#ifndef USE_STRUCT_CONVENTION
+#define USE_STRUCT_CONVENTION(gcc_p,type) generic_use_struct_convention (gcc_p, type)
+#endif
+
+/* Some fundamental types (such as long double) are returned on the stack for
+   certain architectures.  This macro should return true for any type besides
+   struct, union or array that gets returned on the stack.  */
+
+#ifndef RETURN_VALUE_ON_STACK
+#define RETURN_VALUE_ON_STACK(TYPE) 0
+#endif
+
+/* Return true if the function specified is using the structure returning
+   convention on this machine to return arguments, or 0 if it is using
+   the value returning convention.  FUNCTION is the value representing
+   the function, FUNCADDR is the address of the function, and VALUE_TYPE
+   is the type returned by the function.  GCC_P is nonzero if compiled
+   with GCC.  */
+
+int
+using_struct_return (function, funcaddr, value_type, gcc_p)
+     value_ptr function;
+     CORE_ADDR funcaddr;
+     struct type *value_type;
+     int gcc_p;
+     /*ARGSUSED*/
+{
+  register enum type_code code = TYPE_CODE (value_type);
+
+  if (code == TYPE_CODE_ERROR)
+    error ("Function return type unknown.");
+
+  if (code == TYPE_CODE_STRUCT
+      || code == TYPE_CODE_UNION
+      || code == TYPE_CODE_ARRAY
+      || RETURN_VALUE_ON_STACK (value_type))
+    return USE_STRUCT_CONVENTION (gcc_p, value_type);
+
+  return 0;
+}
+
+/* Store VAL so it will be returned if a function returns now.
+   Does not verify that VAL's type matches what the current
+   function wants to return.  */
+
+void
+set_return_value (val)
+     value_ptr val;
+{
+  struct type *type = check_typedef (VALUE_TYPE (val));
+  register enum type_code code = TYPE_CODE (type);
+
+  if (code == TYPE_CODE_ERROR)
+    error ("Function return type unknown.");
+
+  if (   code == TYPE_CODE_STRUCT
+      || code == TYPE_CODE_UNION)	/* FIXME, implement struct return.  */
+    error ("GDB does not support specifying a struct or union return value.");
+
+  STORE_RETURN_VALUE (type, VALUE_CONTENTS (val));
+}
+
+void
+_initialize_values ()
+{
+  add_cmd ("convenience", no_class, show_convenience,
+	    "Debugger convenience (\"$foo\") variables.\n\
+These variables are created when you assign them values;\n\
+thus, \"print $foo=1\" gives \"$foo\" the value 1.  Values may be any type.\n\n\
+A few convenience variables are given values automatically:\n\
+\"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
+\"$__\" holds the contents of the last address examined with \"x\".",
+	   &showlist);
+
+  add_cmd ("values", no_class, show_values,
+	   "Elements of value history around item number IDX (or last ten).",
+	   &showlist);
+}