1352 lines
41 KiB
C
1352 lines
41 KiB
C
/* Low level packing and unpacking of values for GDB, the GNU Debugger.
|
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Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
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1995, 1996, 1997, 1998, 1999, 2000, 2002.
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Free Software Foundation, Inc.
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This file is part of GDB.
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|
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
|
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(at your option) any later version.
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||
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "defs.h"
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#include "gdb_string.h"
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#include "symtab.h"
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#include "gdbtypes.h"
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#include "value.h"
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#include "gdbcore.h"
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#include "command.h"
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#include "gdbcmd.h"
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#include "target.h"
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#include "language.h"
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#include "scm-lang.h"
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#include "demangle.h"
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#include "doublest.h"
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#include "gdb_assert.h"
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#include "regcache.h"
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/* Prototypes for exported functions. */
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void _initialize_values (void);
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/* Prototypes for local functions. */
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static void show_values (char *, int);
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static void show_convenience (char *, int);
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/* The value-history records all the values printed
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by print commands during this session. Each chunk
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records 60 consecutive values. The first chunk on
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the chain records the most recent values.
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The total number of values is in value_history_count. */
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#define VALUE_HISTORY_CHUNK 60
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struct value_history_chunk
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{
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struct value_history_chunk *next;
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struct value *values[VALUE_HISTORY_CHUNK];
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};
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/* Chain of chunks now in use. */
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static struct value_history_chunk *value_history_chain;
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static int value_history_count; /* Abs number of last entry stored */
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/* List of all value objects currently allocated
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(except for those released by calls to release_value)
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This is so they can be freed after each command. */
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static struct value *all_values;
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/* Allocate a value that has the correct length for type TYPE. */
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struct value *
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allocate_value (struct type *type)
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{
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struct value *val;
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struct type *atype = check_typedef (type);
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val = (struct value *) xmalloc (sizeof (struct value) + TYPE_LENGTH (atype));
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VALUE_NEXT (val) = all_values;
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all_values = val;
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VALUE_TYPE (val) = type;
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VALUE_ENCLOSING_TYPE (val) = type;
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VALUE_LVAL (val) = not_lval;
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VALUE_ADDRESS (val) = 0;
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VALUE_FRAME (val) = 0;
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VALUE_OFFSET (val) = 0;
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VALUE_BITPOS (val) = 0;
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VALUE_BITSIZE (val) = 0;
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VALUE_REGNO (val) = -1;
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VALUE_LAZY (val) = 0;
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VALUE_OPTIMIZED_OUT (val) = 0;
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VALUE_BFD_SECTION (val) = NULL;
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VALUE_EMBEDDED_OFFSET (val) = 0;
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VALUE_POINTED_TO_OFFSET (val) = 0;
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val->modifiable = 1;
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return val;
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}
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/* Allocate a value that has the correct length
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for COUNT repetitions type TYPE. */
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struct value *
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allocate_repeat_value (struct type *type, int count)
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{
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int low_bound = current_language->string_lower_bound; /* ??? */
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/* FIXME-type-allocation: need a way to free this type when we are
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done with it. */
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struct type *range_type
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= create_range_type ((struct type *) NULL, builtin_type_int,
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low_bound, count + low_bound - 1);
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/* FIXME-type-allocation: need a way to free this type when we are
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done with it. */
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return allocate_value (create_array_type ((struct type *) NULL,
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type, range_type));
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}
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/* Return a mark in the value chain. All values allocated after the
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mark is obtained (except for those released) are subject to being freed
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if a subsequent value_free_to_mark is passed the mark. */
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struct value *
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value_mark (void)
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{
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return all_values;
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}
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/* Free all values allocated since MARK was obtained by value_mark
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(except for those released). */
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void
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value_free_to_mark (struct value *mark)
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{
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struct value *val;
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struct value *next;
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for (val = all_values; val && val != mark; val = next)
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{
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next = VALUE_NEXT (val);
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value_free (val);
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}
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all_values = val;
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}
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/* Free all the values that have been allocated (except for those released).
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Called after each command, successful or not. */
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void
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free_all_values (void)
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{
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struct value *val;
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struct value *next;
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for (val = all_values; val; val = next)
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{
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next = VALUE_NEXT (val);
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value_free (val);
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}
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all_values = 0;
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}
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/* Remove VAL from the chain all_values
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so it will not be freed automatically. */
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void
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release_value (struct value *val)
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{
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struct value *v;
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if (all_values == val)
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{
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all_values = val->next;
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return;
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}
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for (v = all_values; v; v = v->next)
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{
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if (v->next == val)
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{
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v->next = val->next;
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break;
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}
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}
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}
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/* Release all values up to mark */
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struct value *
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value_release_to_mark (struct value *mark)
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{
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struct value *val;
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struct value *next;
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for (val = next = all_values; next; next = VALUE_NEXT (next))
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if (VALUE_NEXT (next) == mark)
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{
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all_values = VALUE_NEXT (next);
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VALUE_NEXT (next) = 0;
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return val;
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}
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all_values = 0;
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return val;
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}
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/* Return a copy of the value ARG.
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It contains the same contents, for same memory address,
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but it's a different block of storage. */
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struct value *
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value_copy (struct value *arg)
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{
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register struct type *encl_type = VALUE_ENCLOSING_TYPE (arg);
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struct value *val = allocate_value (encl_type);
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VALUE_TYPE (val) = VALUE_TYPE (arg);
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VALUE_LVAL (val) = VALUE_LVAL (arg);
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VALUE_ADDRESS (val) = VALUE_ADDRESS (arg);
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VALUE_OFFSET (val) = VALUE_OFFSET (arg);
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VALUE_BITPOS (val) = VALUE_BITPOS (arg);
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VALUE_BITSIZE (val) = VALUE_BITSIZE (arg);
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VALUE_FRAME (val) = VALUE_FRAME (arg);
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VALUE_REGNO (val) = VALUE_REGNO (arg);
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VALUE_LAZY (val) = VALUE_LAZY (arg);
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VALUE_OPTIMIZED_OUT (val) = VALUE_OPTIMIZED_OUT (arg);
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VALUE_EMBEDDED_OFFSET (val) = VALUE_EMBEDDED_OFFSET (arg);
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VALUE_POINTED_TO_OFFSET (val) = VALUE_POINTED_TO_OFFSET (arg);
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VALUE_BFD_SECTION (val) = VALUE_BFD_SECTION (arg);
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val->modifiable = arg->modifiable;
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if (!VALUE_LAZY (val))
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{
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memcpy (VALUE_CONTENTS_ALL_RAW (val), VALUE_CONTENTS_ALL_RAW (arg),
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TYPE_LENGTH (VALUE_ENCLOSING_TYPE (arg)));
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}
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return val;
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}
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/* Access to the value history. */
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/* Record a new value in the value history.
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Returns the absolute history index of the entry.
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Result of -1 indicates the value was not saved; otherwise it is the
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value history index of this new item. */
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int
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record_latest_value (struct value *val)
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{
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int i;
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/* We don't want this value to have anything to do with the inferior anymore.
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In particular, "set $1 = 50" should not affect the variable from which
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the value was taken, and fast watchpoints should be able to assume that
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a value on the value history never changes. */
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if (VALUE_LAZY (val))
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value_fetch_lazy (val);
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/* We preserve VALUE_LVAL so that the user can find out where it was fetched
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from. This is a bit dubious, because then *&$1 does not just return $1
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but the current contents of that location. c'est la vie... */
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val->modifiable = 0;
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release_value (val);
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/* Here we treat value_history_count as origin-zero
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and applying to the value being stored now. */
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i = value_history_count % VALUE_HISTORY_CHUNK;
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if (i == 0)
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{
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struct value_history_chunk *new
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= (struct value_history_chunk *)
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xmalloc (sizeof (struct value_history_chunk));
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memset (new->values, 0, sizeof new->values);
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new->next = value_history_chain;
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value_history_chain = new;
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}
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value_history_chain->values[i] = val;
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/* Now we regard value_history_count as origin-one
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and applying to the value just stored. */
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return ++value_history_count;
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}
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/* Return a copy of the value in the history with sequence number NUM. */
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struct value *
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access_value_history (int num)
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{
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struct value_history_chunk *chunk;
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register int i;
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register int absnum = num;
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if (absnum <= 0)
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absnum += value_history_count;
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if (absnum <= 0)
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{
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if (num == 0)
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error ("The history is empty.");
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else if (num == 1)
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error ("There is only one value in the history.");
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else
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error ("History does not go back to $$%d.", -num);
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}
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if (absnum > value_history_count)
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error ("History has not yet reached $%d.", absnum);
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absnum--;
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/* Now absnum is always absolute and origin zero. */
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chunk = value_history_chain;
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for (i = (value_history_count - 1) / VALUE_HISTORY_CHUNK - absnum / VALUE_HISTORY_CHUNK;
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i > 0; i--)
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chunk = chunk->next;
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return value_copy (chunk->values[absnum % VALUE_HISTORY_CHUNK]);
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}
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/* Clear the value history entirely.
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Must be done when new symbol tables are loaded,
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because the type pointers become invalid. */
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void
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clear_value_history (void)
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{
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struct value_history_chunk *next;
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register int i;
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struct value *val;
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while (value_history_chain)
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{
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for (i = 0; i < VALUE_HISTORY_CHUNK; i++)
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if ((val = value_history_chain->values[i]) != NULL)
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xfree (val);
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next = value_history_chain->next;
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xfree (value_history_chain);
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value_history_chain = next;
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}
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value_history_count = 0;
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}
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static void
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show_values (char *num_exp, int from_tty)
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{
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register int i;
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struct value *val;
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static int num = 1;
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if (num_exp)
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{
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/* "info history +" should print from the stored position.
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"info history <exp>" should print around value number <exp>. */
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if (num_exp[0] != '+' || num_exp[1] != '\0')
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num = parse_and_eval_long (num_exp) - 5;
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}
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else
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{
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/* "info history" means print the last 10 values. */
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num = value_history_count - 9;
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}
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if (num <= 0)
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num = 1;
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for (i = num; i < num + 10 && i <= value_history_count; i++)
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{
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val = access_value_history (i);
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printf_filtered ("$%d = ", i);
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value_print (val, gdb_stdout, 0, Val_pretty_default);
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printf_filtered ("\n");
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}
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/* The next "info history +" should start after what we just printed. */
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num += 10;
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|
||
/* Hitting just return after this command should do the same thing as
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"info history +". If num_exp is null, this is unnecessary, since
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"info history +" is not useful after "info history". */
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if (from_tty && num_exp)
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{
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num_exp[0] = '+';
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num_exp[1] = '\0';
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||
}
|
||
}
|
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|
||
/* Internal variables. These are variables within the debugger
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||
that hold values assigned by debugger commands.
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The user refers to them with a '$' prefix
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||
that does not appear in the variable names stored internally. */
|
||
|
||
static struct internalvar *internalvars;
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||
|
||
/* Look up an internal variable with name NAME. NAME should not
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||
normally include a dollar sign.
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||
|
||
If the specified internal variable does not exist,
|
||
one is created, with a void value. */
|
||
|
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struct internalvar *
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||
lookup_internalvar (char *name)
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||
{
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||
register struct internalvar *var;
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||
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for (var = internalvars; var; var = var->next)
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if (STREQ (var->name, name))
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return var;
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||
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var = (struct internalvar *) xmalloc (sizeof (struct internalvar));
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var->name = concat (name, NULL);
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||
var->value = allocate_value (builtin_type_void);
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release_value (var->value);
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var->next = internalvars;
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internalvars = var;
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||
return var;
|
||
}
|
||
|
||
struct value *
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||
value_of_internalvar (struct internalvar *var)
|
||
{
|
||
struct value *val;
|
||
|
||
#ifdef IS_TRAPPED_INTERNALVAR
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if (IS_TRAPPED_INTERNALVAR (var->name))
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return VALUE_OF_TRAPPED_INTERNALVAR (var);
|
||
#endif
|
||
|
||
val = value_copy (var->value);
|
||
if (VALUE_LAZY (val))
|
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value_fetch_lazy (val);
|
||
VALUE_LVAL (val) = lval_internalvar;
|
||
VALUE_INTERNALVAR (val) = var;
|
||
return val;
|
||
}
|
||
|
||
void
|
||
set_internalvar_component (struct internalvar *var, int offset, int bitpos,
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||
int bitsize, struct value *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 (struct internalvar *var, struct value *val)
|
||
{
|
||
struct value *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. */
|
||
xfree (var->value);
|
||
var->value = newval;
|
||
release_value (newval);
|
||
/* End code which must not call error(). */
|
||
}
|
||
|
||
char *
|
||
internalvar_name (struct internalvar *var)
|
||
{
|
||
return var->name;
|
||
}
|
||
|
||
/* Free all internalvars. Done when new symtabs are loaded,
|
||
because that makes the values invalid. */
|
||
|
||
void
|
||
clear_internalvars (void)
|
||
{
|
||
register struct internalvar *var;
|
||
|
||
while (internalvars)
|
||
{
|
||
var = internalvars;
|
||
internalvars = var->next;
|
||
xfree (var->name);
|
||
xfree (var->value);
|
||
xfree (var);
|
||
}
|
||
}
|
||
|
||
static void
|
||
show_convenience (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 (struct value *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 (struct value *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.
|
||
Note that val's type may not actually be a pointer; value_as_long
|
||
handles all the cases. */
|
||
CORE_ADDR
|
||
value_as_address (struct value *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
|
||
|
||
/* There are several targets (IA-64, PowerPC, and others) which
|
||
don't represent pointers to functions as simply the address of
|
||
the function's entry point. For example, on the IA-64, a
|
||
function pointer points to a two-word descriptor, generated by
|
||
the linker, which contains the function's entry point, and the
|
||
value the IA-64 "global pointer" register should have --- to
|
||
support position-independent code. The linker generates
|
||
descriptors only for those functions whose addresses are taken.
|
||
|
||
On such targets, it's difficult for GDB to convert an arbitrary
|
||
function address into a function pointer; it has to either find
|
||
an existing descriptor for that function, or call malloc and
|
||
build its own. On some targets, it is impossible for GDB to
|
||
build a descriptor at all: the descriptor must contain a jump
|
||
instruction; data memory cannot be executed; and code memory
|
||
cannot be modified.
|
||
|
||
Upon entry to this function, if VAL is a value of type `function'
|
||
(that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
|
||
VALUE_ADDRESS (val) is the address of the function. This is what
|
||
you'll get if you evaluate an expression like `main'. The call
|
||
to COERCE_ARRAY below actually does all the usual unary
|
||
conversions, which includes converting values of type `function'
|
||
to `pointer to function'. This is the challenging conversion
|
||
discussed above. Then, `unpack_long' will convert that pointer
|
||
back into an address.
|
||
|
||
So, suppose the user types `disassemble foo' on an architecture
|
||
with a strange function pointer representation, on which GDB
|
||
cannot build its own descriptors, and suppose further that `foo'
|
||
has no linker-built descriptor. The address->pointer conversion
|
||
will signal an error and prevent the command from running, even
|
||
though the next step would have been to convert the pointer
|
||
directly back into the same address.
|
||
|
||
The following shortcut avoids this whole mess. If VAL is a
|
||
function, just return its address directly. */
|
||
if (TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC
|
||
|| TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_METHOD)
|
||
return VALUE_ADDRESS (val);
|
||
|
||
COERCE_ARRAY (val);
|
||
|
||
/* Some architectures (e.g. Harvard), map instruction and data
|
||
addresses onto a single large unified address space. For
|
||
instance: An architecture may consider a large integer in the
|
||
range 0x10000000 .. 0x1000ffff to already represent a data
|
||
addresses (hence not need a pointer to address conversion) while
|
||
a small integer would still need to be converted integer to
|
||
pointer to address. Just assume such architectures handle all
|
||
integer conversions in a single function. */
|
||
|
||
/* JimB writes:
|
||
|
||
I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
|
||
must admonish GDB hackers to make sure its behavior matches the
|
||
compiler's, whenever possible.
|
||
|
||
In general, I think GDB should evaluate expressions the same way
|
||
the compiler does. When the user copies an expression out of
|
||
their source code and hands it to a `print' command, they should
|
||
get the same value the compiler would have computed. Any
|
||
deviation from this rule can cause major confusion and annoyance,
|
||
and needs to be justified carefully. In other words, GDB doesn't
|
||
really have the freedom to do these conversions in clever and
|
||
useful ways.
|
||
|
||
AndrewC pointed out that users aren't complaining about how GDB
|
||
casts integers to pointers; they are complaining that they can't
|
||
take an address from a disassembly listing and give it to `x/i'.
|
||
This is certainly important.
|
||
|
||
Adding an architecture method like INTEGER_TO_ADDRESS certainly
|
||
makes it possible for GDB to "get it right" in all circumstances
|
||
--- the target has complete control over how things get done, so
|
||
people can Do The Right Thing for their target without breaking
|
||
anyone else. The standard doesn't specify how integers get
|
||
converted to pointers; usually, the ABI doesn't either, but
|
||
ABI-specific code is a more reasonable place to handle it. */
|
||
|
||
if (TYPE_CODE (VALUE_TYPE (val)) != TYPE_CODE_PTR
|
||
&& TYPE_CODE (VALUE_TYPE (val)) != TYPE_CODE_REF
|
||
&& INTEGER_TO_ADDRESS_P ())
|
||
return INTEGER_TO_ADDRESS (VALUE_TYPE (val), VALUE_CONTENTS (val));
|
||
|
||
return unpack_long (VALUE_TYPE (val), VALUE_CONTENTS (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 (struct type *type, const 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_typed_floating (valaddr, type);
|
||
|
||
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. */
|
||
return extract_typed_address (valaddr, type);
|
||
|
||
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 (struct type *type, const 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)
|
||
{
|
||
/* NOTE: cagney/2002-02-19: There was a test here to see if the
|
||
floating-point value was valid (using the macro
|
||
INVALID_FLOAT). That test/macro have been removed.
|
||
|
||
It turns out that only the VAX defined this macro and then
|
||
only in a non-portable way. Fixing the portability problem
|
||
wouldn't help since the VAX floating-point code is also badly
|
||
bit-rotten. The target needs to add definitions for the
|
||
methods TARGET_FLOAT_FORMAT and TARGET_DOUBLE_FORMAT - these
|
||
exactly describe the target floating-point format. The
|
||
problem here is that the corresponding floatformat_vax_f and
|
||
floatformat_vax_d values these methods should be set to are
|
||
also not defined either. Oops!
|
||
|
||
Hopefully someone will add both the missing floatformat
|
||
definitions and floatformat_is_invalid() function. */
|
||
return extract_typed_floating (valaddr, type);
|
||
}
|
||
else if (nosign)
|
||
{
|
||
/* Unsigned -- be sure we compensate for signed LONGEST. */
|
||
return (ULONGEST) unpack_long (type, valaddr);
|
||
}
|
||
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_address() 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 (struct type *type, const 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. Return NULL if the field doesn't exist or has been
|
||
optimized out. */
|
||
|
||
struct value *
|
||
value_static_field (struct type *type, int fieldno)
|
||
{
|
||
struct value *retval;
|
||
|
||
if (TYPE_FIELD_STATIC_HAS_ADDR (type, fieldno))
|
||
{
|
||
retval = value_at (TYPE_FIELD_TYPE (type, fieldno),
|
||
TYPE_FIELD_STATIC_PHYSADDR (type, fieldno),
|
||
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
|
||
{
|
||
retval = value_at (TYPE_FIELD_TYPE (type, fieldno),
|
||
SYMBOL_VALUE_ADDRESS (msym),
|
||
SYMBOL_BFD_SECTION (msym));
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* SYM should never have a SYMBOL_CLASS which will require
|
||
read_var_value to use the FRAME parameter. */
|
||
if (symbol_read_needs_frame (sym))
|
||
warning ("static field's value depends on the current "
|
||
"frame - bad debug info?");
|
||
retval = read_var_value (sym, NULL);
|
||
}
|
||
if (retval && VALUE_LVAL (retval) == lval_memory)
|
||
SET_FIELD_PHYSADDR (TYPE_FIELD (type, fieldno),
|
||
VALUE_ADDRESS (retval));
|
||
}
|
||
return retval;
|
||
}
|
||
|
||
/* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
|
||
You have to be careful here, since the size of the data area for the value
|
||
is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
|
||
than the old enclosing type, you have to allocate more space for the data.
|
||
The return value is a pointer to the new version of this value structure. */
|
||
|
||
struct value *
|
||
value_change_enclosing_type (struct value *val, struct type *new_encl_type)
|
||
{
|
||
if (TYPE_LENGTH (new_encl_type) <= TYPE_LENGTH (VALUE_ENCLOSING_TYPE (val)))
|
||
{
|
||
VALUE_ENCLOSING_TYPE (val) = new_encl_type;
|
||
return val;
|
||
}
|
||
else
|
||
{
|
||
struct value *new_val;
|
||
struct value *prev;
|
||
|
||
new_val = (struct value *) xrealloc (val, sizeof (struct value) + TYPE_LENGTH (new_encl_type));
|
||
|
||
VALUE_ENCLOSING_TYPE (new_val) = new_encl_type;
|
||
|
||
/* We have to make sure this ends up in the same place in the value
|
||
chain as the original copy, so it's clean-up behavior is the same.
|
||
If the value has been released, this is a waste of time, but there
|
||
is no way to tell that in advance, so... */
|
||
|
||
if (val != all_values)
|
||
{
|
||
for (prev = all_values; prev != NULL; prev = prev->next)
|
||
{
|
||
if (prev->next == val)
|
||
{
|
||
prev->next = new_val;
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
return new_val;
|
||
}
|
||
}
|
||
|
||
/* 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. */
|
||
|
||
struct value *
|
||
value_primitive_field (struct value *arg1, int offset,
|
||
register int fieldno, register struct type *arg_type)
|
||
{
|
||
struct value *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);
|
||
VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset
|
||
+ TYPE_FIELD_BITPOS (arg_type, fieldno) / 8;
|
||
}
|
||
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) = 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_EMBEDDED_OFFSET (arg1);
|
||
}
|
||
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_REGNO (v) = VALUE_REGNO (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. */
|
||
|
||
struct value *
|
||
value_field (struct value *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.
|
||
|
||
We only use the symbol for its address, so be happy with either a
|
||
full symbol or a minimal symbol.
|
||
*/
|
||
|
||
struct value *
|
||
value_fn_field (struct value **arg1p, struct fn_field *f, int j, struct type *type,
|
||
int offset)
|
||
{
|
||
struct value *v;
|
||
register struct type *ftype = TYPE_FN_FIELD_TYPE (f, j);
|
||
char *physname = TYPE_FN_FIELD_PHYSNAME (f, j);
|
||
struct symbol *sym;
|
||
struct minimal_symbol *msym;
|
||
|
||
sym = lookup_symbol (physname, 0, VAR_NAMESPACE, 0, NULL);
|
||
if (sym != NULL)
|
||
{
|
||
msym = NULL;
|
||
}
|
||
else
|
||
{
|
||
gdb_assert (sym == NULL);
|
||
msym = lookup_minimal_symbol (physname, NULL, NULL);
|
||
if (msym == NULL)
|
||
return NULL;
|
||
}
|
||
|
||
v = allocate_value (ftype);
|
||
if (sym)
|
||
{
|
||
VALUE_ADDRESS (v) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym));
|
||
}
|
||
else
|
||
{
|
||
VALUE_ADDRESS (v) = SYMBOL_VALUE_ADDRESS (msym);
|
||
}
|
||
|
||
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;
|
||
}
|
||
|
||
|
||
/* 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 (struct type *type, const 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 (char *addr, LONGEST fieldval, int bitpos, int 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 */
|
||
|
||
struct value *
|
||
value_from_longest (struct type *type, register LONGEST num)
|
||
{
|
||
struct value *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:
|
||
store_typed_address (VALUE_CONTENTS_RAW (val), type, (CORE_ADDR) num);
|
||
break;
|
||
|
||
default:
|
||
error ("Unexpected type (%d) encountered for integer constant.", code);
|
||
}
|
||
return val;
|
||
}
|
||
|
||
|
||
/* Create a value representing a pointer of type TYPE to the address
|
||
ADDR. */
|
||
struct value *
|
||
value_from_pointer (struct type *type, CORE_ADDR addr)
|
||
{
|
||
struct value *val = allocate_value (type);
|
||
store_typed_address (VALUE_CONTENTS_RAW (val), type, addr);
|
||
return val;
|
||
}
|
||
|
||
|
||
/* Create a value for a string constant to be stored locally
|
||
(not in the inferior's memory space, but in GDB memory).
|
||
This is analogous to value_from_longest, which also does not
|
||
use inferior memory. String shall NOT contain embedded nulls. */
|
||
|
||
struct value *
|
||
value_from_string (char *ptr)
|
||
{
|
||
struct value *val;
|
||
int len = strlen (ptr);
|
||
int lowbound = current_language->string_lower_bound;
|
||
struct type *rangetype =
|
||
create_range_type ((struct type *) NULL,
|
||
builtin_type_int,
|
||
lowbound, len + lowbound - 1);
|
||
struct type *stringtype =
|
||
create_array_type ((struct type *) NULL,
|
||
*current_language->string_char_type,
|
||
rangetype);
|
||
|
||
val = allocate_value (stringtype);
|
||
memcpy (VALUE_CONTENTS_RAW (val), ptr, len);
|
||
return val;
|
||
}
|
||
|
||
struct value *
|
||
value_from_double (struct type *type, DOUBLEST num)
|
||
{
|
||
struct value *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_typed_floating (VALUE_CONTENTS_RAW (val), base_type, 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). */
|
||
|
||
/* ARGSUSED */
|
||
struct value *
|
||
value_being_returned (struct type *valtype, struct regcache *retbuf,
|
||
int struct_return)
|
||
{
|
||
struct value *val;
|
||
CORE_ADDR addr;
|
||
|
||
/* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */
|
||
if (EXTRACT_STRUCT_VALUE_ADDRESS_P ())
|
||
if (struct_return)
|
||
{
|
||
addr = EXTRACT_STRUCT_VALUE_ADDRESS (retbuf);
|
||
if (!addr)
|
||
error ("Function return value unknown.");
|
||
return value_at (valtype, addr, NULL);
|
||
}
|
||
|
||
/* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */
|
||
if (DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS_P ())
|
||
if (struct_return)
|
||
{
|
||
char *buf = deprecated_grub_regcache_for_registers (retbuf);
|
||
addr = DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS (buf);
|
||
if (!addr)
|
||
error ("Function return value unknown.");
|
||
return value_at (valtype, addr, NULL);
|
||
}
|
||
|
||
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 (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));
|
||
}
|
||
|
||
/* 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. */
|
||
|
||
/* ARGSUSED */
|
||
int
|
||
using_struct_return (struct value *function, CORE_ADDR funcaddr,
|
||
struct type *value_type, int gcc_p)
|
||
{
|
||
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 (struct value *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, current_regcache, VALUE_CONTENTS (val));
|
||
}
|
||
|
||
void
|
||
_initialize_values (void)
|
||
{
|
||
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);
|
||
}
|