1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
3 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
4 1996, 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
5 2009, 2010 Free Software Foundation, Inc.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "arch-utils.h"
24 #include "gdb_string.h"
35 #include "gdb_assert.h"
41 #include "cli/cli-decode.h"
43 #include "python/python.h"
45 /* Prototypes for exported functions. */
47 void _initialize_values (void);
49 /* Definition of a user function. */
50 struct internal_function
52 /* The name of the function. It is a bit odd to have this in the
53 function itself -- the user might use a differently-named
54 convenience variable to hold the function. */
58 internal_function_fn handler;
60 /* User data for the handler. */
64 static struct cmd_list_element *functionlist;
68 /* Type of value; either not an lval, or one of the various
69 different possible kinds of lval. */
72 /* Is it modifiable? Only relevant if lval != not_lval. */
75 /* Location of value (if lval). */
78 /* If lval == lval_memory, this is the address in the inferior.
79 If lval == lval_register, this is the byte offset into the
80 registers structure. */
83 /* Pointer to internal variable. */
84 struct internalvar *internalvar;
86 /* If lval == lval_computed, this is a set of function pointers
87 to use to access and describe the value, and a closure pointer
91 struct lval_funcs *funcs; /* Functions to call. */
92 void *closure; /* Closure for those functions to use. */
96 /* Describes offset of a value within lval of a structure in bytes.
97 If lval == lval_memory, this is an offset to the address. If
98 lval == lval_register, this is a further offset from
99 location.address within the registers structure. Note also the
100 member embedded_offset below. */
103 /* Only used for bitfields; number of bits contained in them. */
106 /* Only used for bitfields; position of start of field. For
107 gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
108 gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
111 /* Only used for bitfields; the containing value. This allows a
112 single read from the target when displaying multiple
114 struct value *parent;
116 /* Frame register value is relative to. This will be described in
117 the lval enum above as "lval_register". */
118 struct frame_id frame_id;
120 /* Type of the value. */
123 /* If a value represents a C++ object, then the `type' field gives
124 the object's compile-time type. If the object actually belongs
125 to some class derived from `type', perhaps with other base
126 classes and additional members, then `type' is just a subobject
127 of the real thing, and the full object is probably larger than
128 `type' would suggest.
130 If `type' is a dynamic class (i.e. one with a vtable), then GDB
131 can actually determine the object's run-time type by looking at
132 the run-time type information in the vtable. When this
133 information is available, we may elect to read in the entire
134 object, for several reasons:
136 - When printing the value, the user would probably rather see the
137 full object, not just the limited portion apparent from the
140 - If `type' has virtual base classes, then even printing `type'
141 alone may require reaching outside the `type' portion of the
142 object to wherever the virtual base class has been stored.
144 When we store the entire object, `enclosing_type' is the run-time
145 type -- the complete object -- and `embedded_offset' is the
146 offset of `type' within that larger type, in bytes. The
147 value_contents() macro takes `embedded_offset' into account, so
148 most GDB code continues to see the `type' portion of the value,
149 just as the inferior would.
151 If `type' is a pointer to an object, then `enclosing_type' is a
152 pointer to the object's run-time type, and `pointed_to_offset' is
153 the offset in bytes from the full object to the pointed-to object
154 -- that is, the value `embedded_offset' would have if we followed
155 the pointer and fetched the complete object. (I don't really see
156 the point. Why not just determine the run-time type when you
157 indirect, and avoid the special case? The contents don't matter
158 until you indirect anyway.)
160 If we're not doing anything fancy, `enclosing_type' is equal to
161 `type', and `embedded_offset' is zero, so everything works
163 struct type *enclosing_type;
165 int pointed_to_offset;
167 /* Values are stored in a chain, so that they can be deleted easily
168 over calls to the inferior. Values assigned to internal
169 variables, put into the value history or exposed to Python are
170 taken off this list. */
173 /* Register number if the value is from a register. */
176 /* If zero, contents of this value are in the contents field. If
177 nonzero, contents are in inferior. If the lval field is lval_memory,
178 the contents are in inferior memory at location.address plus offset.
179 The lval field may also be lval_register.
181 WARNING: This field is used by the code which handles watchpoints
182 (see breakpoint.c) to decide whether a particular value can be
183 watched by hardware watchpoints. If the lazy flag is set for
184 some member of a value chain, it is assumed that this member of
185 the chain doesn't need to be watched as part of watching the
186 value itself. This is how GDB avoids watching the entire struct
187 or array when the user wants to watch a single struct member or
188 array element. If you ever change the way lazy flag is set and
189 reset, be sure to consider this use as well! */
192 /* If nonzero, this is the value of a variable which does not
193 actually exist in the program. */
196 /* If value is a variable, is it initialized or not. */
199 /* If value is from the stack. If this is set, read_stack will be
200 used instead of read_memory to enable extra caching. */
203 /* Actual contents of the value. Target byte-order. NULL or not
204 valid if lazy is nonzero. */
207 /* The number of references to this value. When a value is created,
208 the value chain holds a reference, so REFERENCE_COUNT is 1. If
209 release_value is called, this value is removed from the chain but
210 the caller of release_value now has a reference to this value.
211 The caller must arrange for a call to value_free later. */
215 /* Prototypes for local functions. */
217 static void show_values (char *, int);
219 static void show_convenience (char *, int);
222 /* The value-history records all the values printed
223 by print commands during this session. Each chunk
224 records 60 consecutive values. The first chunk on
225 the chain records the most recent values.
226 The total number of values is in value_history_count. */
228 #define VALUE_HISTORY_CHUNK 60
230 struct value_history_chunk
232 struct value_history_chunk *next;
233 struct value *values[VALUE_HISTORY_CHUNK];
236 /* Chain of chunks now in use. */
238 static struct value_history_chunk *value_history_chain;
240 static int value_history_count; /* Abs number of last entry stored */
243 /* List of all value objects currently allocated
244 (except for those released by calls to release_value)
245 This is so they can be freed after each command. */
247 static struct value *all_values;
249 /* Allocate a lazy value for type TYPE. Its actual content is
250 "lazily" allocated too: the content field of the return value is
251 NULL; it will be allocated when it is fetched from the target. */
254 allocate_value_lazy (struct type *type)
258 /* Call check_typedef on our type to make sure that, if TYPE
259 is a TYPE_CODE_TYPEDEF, its length is set to the length
260 of the target type instead of zero. However, we do not
261 replace the typedef type by the target type, because we want
262 to keep the typedef in order to be able to set the VAL's type
263 description correctly. */
264 check_typedef (type);
266 val = (struct value *) xzalloc (sizeof (struct value));
267 val->contents = NULL;
268 val->next = all_values;
271 val->enclosing_type = type;
272 VALUE_LVAL (val) = not_lval;
273 val->location.address = 0;
274 VALUE_FRAME_ID (val) = null_frame_id;
278 VALUE_REGNUM (val) = -1;
280 val->optimized_out = 0;
281 val->embedded_offset = 0;
282 val->pointed_to_offset = 0;
284 val->initialized = 1; /* Default to initialized. */
286 /* Values start out on the all_values chain. */
287 val->reference_count = 1;
292 /* Allocate the contents of VAL if it has not been allocated yet. */
295 allocate_value_contents (struct value *val)
298 val->contents = (gdb_byte *) xzalloc (TYPE_LENGTH (val->enclosing_type));
301 /* Allocate a value and its contents for type TYPE. */
304 allocate_value (struct type *type)
306 struct value *val = allocate_value_lazy (type);
307 allocate_value_contents (val);
312 /* Allocate a value that has the correct length
313 for COUNT repetitions of type TYPE. */
316 allocate_repeat_value (struct type *type, int count)
318 int low_bound = current_language->string_lower_bound; /* ??? */
319 /* FIXME-type-allocation: need a way to free this type when we are
321 struct type *array_type
322 = lookup_array_range_type (type, low_bound, count + low_bound - 1);
323 return allocate_value (array_type);
327 allocate_computed_value (struct type *type,
328 struct lval_funcs *funcs,
331 struct value *v = allocate_value (type);
332 VALUE_LVAL (v) = lval_computed;
333 v->location.computed.funcs = funcs;
334 v->location.computed.closure = closure;
335 set_value_lazy (v, 1);
340 /* Accessor methods. */
343 value_next (struct value *value)
349 value_type (struct value *value)
354 deprecated_set_value_type (struct value *value, struct type *type)
360 value_offset (struct value *value)
362 return value->offset;
365 set_value_offset (struct value *value, int offset)
367 value->offset = offset;
371 value_bitpos (struct value *value)
373 return value->bitpos;
376 set_value_bitpos (struct value *value, int bit)
382 value_bitsize (struct value *value)
384 return value->bitsize;
387 set_value_bitsize (struct value *value, int bit)
389 value->bitsize = bit;
393 value_parent (struct value *value)
395 return value->parent;
399 value_contents_raw (struct value *value)
401 allocate_value_contents (value);
402 return value->contents + value->embedded_offset;
406 value_contents_all_raw (struct value *value)
408 allocate_value_contents (value);
409 return value->contents;
413 value_enclosing_type (struct value *value)
415 return value->enclosing_type;
419 value_contents_all (struct value *value)
422 value_fetch_lazy (value);
423 return value->contents;
427 value_lazy (struct value *value)
433 set_value_lazy (struct value *value, int val)
439 value_stack (struct value *value)
445 set_value_stack (struct value *value, int val)
451 value_contents (struct value *value)
453 return value_contents_writeable (value);
457 value_contents_writeable (struct value *value)
460 value_fetch_lazy (value);
461 return value_contents_raw (value);
464 /* Return non-zero if VAL1 and VAL2 have the same contents. Note that
465 this function is different from value_equal; in C the operator ==
466 can return 0 even if the two values being compared are equal. */
469 value_contents_equal (struct value *val1, struct value *val2)
475 type1 = check_typedef (value_type (val1));
476 type2 = check_typedef (value_type (val2));
477 len = TYPE_LENGTH (type1);
478 if (len != TYPE_LENGTH (type2))
481 return (memcmp (value_contents (val1), value_contents (val2), len) == 0);
485 value_optimized_out (struct value *value)
487 return value->optimized_out;
491 set_value_optimized_out (struct value *value, int val)
493 value->optimized_out = val;
497 value_embedded_offset (struct value *value)
499 return value->embedded_offset;
503 set_value_embedded_offset (struct value *value, int val)
505 value->embedded_offset = val;
509 value_pointed_to_offset (struct value *value)
511 return value->pointed_to_offset;
515 set_value_pointed_to_offset (struct value *value, int val)
517 value->pointed_to_offset = val;
521 value_computed_funcs (struct value *v)
523 gdb_assert (VALUE_LVAL (v) == lval_computed);
525 return v->location.computed.funcs;
529 value_computed_closure (struct value *v)
531 gdb_assert (VALUE_LVAL (v) == lval_computed);
533 return v->location.computed.closure;
537 deprecated_value_lval_hack (struct value *value)
543 value_address (struct value *value)
545 if (value->lval == lval_internalvar
546 || value->lval == lval_internalvar_component)
548 return value->location.address + value->offset;
552 value_raw_address (struct value *value)
554 if (value->lval == lval_internalvar
555 || value->lval == lval_internalvar_component)
557 return value->location.address;
561 set_value_address (struct value *value, CORE_ADDR addr)
563 gdb_assert (value->lval != lval_internalvar
564 && value->lval != lval_internalvar_component);
565 value->location.address = addr;
568 struct internalvar **
569 deprecated_value_internalvar_hack (struct value *value)
571 return &value->location.internalvar;
575 deprecated_value_frame_id_hack (struct value *value)
577 return &value->frame_id;
581 deprecated_value_regnum_hack (struct value *value)
583 return &value->regnum;
587 deprecated_value_modifiable (struct value *value)
589 return value->modifiable;
592 deprecated_set_value_modifiable (struct value *value, int modifiable)
594 value->modifiable = modifiable;
597 /* Return a mark in the value chain. All values allocated after the
598 mark is obtained (except for those released) are subject to being freed
599 if a subsequent value_free_to_mark is passed the mark. */
606 /* Take a reference to VAL. VAL will not be deallocated until all
607 references are released. */
610 value_incref (struct value *val)
612 val->reference_count++;
615 /* Release a reference to VAL, which was acquired with value_incref.
616 This function is also called to deallocate values from the value
620 value_free (struct value *val)
624 gdb_assert (val->reference_count > 0);
625 val->reference_count--;
626 if (val->reference_count > 0)
629 /* If there's an associated parent value, drop our reference to
631 if (val->parent != NULL)
632 value_free (val->parent);
634 if (VALUE_LVAL (val) == lval_computed)
636 struct lval_funcs *funcs = val->location.computed.funcs;
638 if (funcs->free_closure)
639 funcs->free_closure (val);
642 xfree (val->contents);
647 /* Free all values allocated since MARK was obtained by value_mark
648 (except for those released). */
650 value_free_to_mark (struct value *mark)
655 for (val = all_values; val && val != mark; val = next)
663 /* Free all the values that have been allocated (except for those released).
664 Call after each command, successful or not.
665 In practice this is called before each command, which is sufficient. */
668 free_all_values (void)
673 for (val = all_values; val; val = next)
682 /* Remove VAL from the chain all_values
683 so it will not be freed automatically. */
686 release_value (struct value *val)
690 if (all_values == val)
692 all_values = val->next;
696 for (v = all_values; v; v = v->next)
706 /* Release all values up to mark */
708 value_release_to_mark (struct value *mark)
713 for (val = next = all_values; next; next = next->next)
714 if (next->next == mark)
716 all_values = next->next;
724 /* Return a copy of the value ARG.
725 It contains the same contents, for same memory address,
726 but it's a different block of storage. */
729 value_copy (struct value *arg)
731 struct type *encl_type = value_enclosing_type (arg);
734 if (value_lazy (arg))
735 val = allocate_value_lazy (encl_type);
737 val = allocate_value (encl_type);
738 val->type = arg->type;
739 VALUE_LVAL (val) = VALUE_LVAL (arg);
740 val->location = arg->location;
741 val->offset = arg->offset;
742 val->bitpos = arg->bitpos;
743 val->bitsize = arg->bitsize;
744 VALUE_FRAME_ID (val) = VALUE_FRAME_ID (arg);
745 VALUE_REGNUM (val) = VALUE_REGNUM (arg);
746 val->lazy = arg->lazy;
747 val->optimized_out = arg->optimized_out;
748 val->embedded_offset = value_embedded_offset (arg);
749 val->pointed_to_offset = arg->pointed_to_offset;
750 val->modifiable = arg->modifiable;
751 if (!value_lazy (val))
753 memcpy (value_contents_all_raw (val), value_contents_all_raw (arg),
754 TYPE_LENGTH (value_enclosing_type (arg)));
757 val->parent = arg->parent;
759 value_incref (val->parent);
760 if (VALUE_LVAL (val) == lval_computed)
762 struct lval_funcs *funcs = val->location.computed.funcs;
764 if (funcs->copy_closure)
765 val->location.computed.closure = funcs->copy_closure (val);
771 set_value_component_location (struct value *component, struct value *whole)
773 if (VALUE_LVAL (whole) == lval_internalvar)
774 VALUE_LVAL (component) = lval_internalvar_component;
776 VALUE_LVAL (component) = VALUE_LVAL (whole);
778 component->location = whole->location;
779 if (VALUE_LVAL (whole) == lval_computed)
781 struct lval_funcs *funcs = whole->location.computed.funcs;
783 if (funcs->copy_closure)
784 component->location.computed.closure = funcs->copy_closure (whole);
789 /* Access to the value history. */
791 /* Record a new value in the value history.
792 Returns the absolute history index of the entry.
793 Result of -1 indicates the value was not saved; otherwise it is the
794 value history index of this new item. */
797 record_latest_value (struct value *val)
801 /* We don't want this value to have anything to do with the inferior anymore.
802 In particular, "set $1 = 50" should not affect the variable from which
803 the value was taken, and fast watchpoints should be able to assume that
804 a value on the value history never changes. */
805 if (value_lazy (val))
806 value_fetch_lazy (val);
807 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
808 from. This is a bit dubious, because then *&$1 does not just return $1
809 but the current contents of that location. c'est la vie... */
813 /* Here we treat value_history_count as origin-zero
814 and applying to the value being stored now. */
816 i = value_history_count % VALUE_HISTORY_CHUNK;
819 struct value_history_chunk *new
820 = (struct value_history_chunk *)
821 xmalloc (sizeof (struct value_history_chunk));
822 memset (new->values, 0, sizeof new->values);
823 new->next = value_history_chain;
824 value_history_chain = new;
827 value_history_chain->values[i] = val;
829 /* Now we regard value_history_count as origin-one
830 and applying to the value just stored. */
832 return ++value_history_count;
835 /* Return a copy of the value in the history with sequence number NUM. */
838 access_value_history (int num)
840 struct value_history_chunk *chunk;
845 absnum += value_history_count;
850 error (_("The history is empty."));
852 error (_("There is only one value in the history."));
854 error (_("History does not go back to $$%d."), -num);
856 if (absnum > value_history_count)
857 error (_("History has not yet reached $%d."), absnum);
861 /* Now absnum is always absolute and origin zero. */
863 chunk = value_history_chain;
864 for (i = (value_history_count - 1) / VALUE_HISTORY_CHUNK - absnum / VALUE_HISTORY_CHUNK;
868 return value_copy (chunk->values[absnum % VALUE_HISTORY_CHUNK]);
872 show_values (char *num_exp, int from_tty)
880 /* "show values +" should print from the stored position.
881 "show values <exp>" should print around value number <exp>. */
882 if (num_exp[0] != '+' || num_exp[1] != '\0')
883 num = parse_and_eval_long (num_exp) - 5;
887 /* "show values" means print the last 10 values. */
888 num = value_history_count - 9;
894 for (i = num; i < num + 10 && i <= value_history_count; i++)
896 struct value_print_options opts;
897 val = access_value_history (i);
898 printf_filtered (("$%d = "), i);
899 get_user_print_options (&opts);
900 value_print (val, gdb_stdout, &opts);
901 printf_filtered (("\n"));
904 /* The next "show values +" should start after what we just printed. */
907 /* Hitting just return after this command should do the same thing as
908 "show values +". If num_exp is null, this is unnecessary, since
909 "show values +" is not useful after "show values". */
910 if (from_tty && num_exp)
917 /* Internal variables. These are variables within the debugger
918 that hold values assigned by debugger commands.
919 The user refers to them with a '$' prefix
920 that does not appear in the variable names stored internally. */
924 struct internalvar *next;
927 /* We support various different kinds of content of an internal variable.
928 enum internalvar_kind specifies the kind, and union internalvar_data
929 provides the data associated with this particular kind. */
931 enum internalvar_kind
933 /* The internal variable is empty. */
936 /* The value of the internal variable is provided directly as
937 a GDB value object. */
940 /* A fresh value is computed via a call-back routine on every
941 access to the internal variable. */
942 INTERNALVAR_MAKE_VALUE,
944 /* The internal variable holds a GDB internal convenience function. */
945 INTERNALVAR_FUNCTION,
947 /* The variable holds an integer value. */
950 /* The variable holds a pointer value. */
953 /* The variable holds a GDB-provided string. */
958 union internalvar_data
960 /* A value object used with INTERNALVAR_VALUE. */
963 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
964 internalvar_make_value make_value;
966 /* The internal function used with INTERNALVAR_FUNCTION. */
969 struct internal_function *function;
970 /* True if this is the canonical name for the function. */
974 /* An integer value used with INTERNALVAR_INTEGER. */
977 /* If type is non-NULL, it will be used as the type to generate
978 a value for this internal variable. If type is NULL, a default
979 integer type for the architecture is used. */
984 /* A pointer value used with INTERNALVAR_POINTER. */
991 /* A string value used with INTERNALVAR_STRING. */
996 static struct internalvar *internalvars;
998 /* If the variable does not already exist create it and give it the value given.
999 If no value is given then the default is zero. */
1001 init_if_undefined_command (char* args, int from_tty)
1003 struct internalvar* intvar;
1005 /* Parse the expression - this is taken from set_command(). */
1006 struct expression *expr = parse_expression (args);
1007 register struct cleanup *old_chain =
1008 make_cleanup (free_current_contents, &expr);
1010 /* Validate the expression.
1011 Was the expression an assignment?
1012 Or even an expression at all? */
1013 if (expr->nelts == 0 || expr->elts[0].opcode != BINOP_ASSIGN)
1014 error (_("Init-if-undefined requires an assignment expression."));
1016 /* Extract the variable from the parsed expression.
1017 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
1018 if (expr->elts[1].opcode != OP_INTERNALVAR)
1019 error (_("The first parameter to init-if-undefined should be a GDB variable."));
1020 intvar = expr->elts[2].internalvar;
1022 /* Only evaluate the expression if the lvalue is void.
1023 This may still fail if the expresssion is invalid. */
1024 if (intvar->kind == INTERNALVAR_VOID)
1025 evaluate_expression (expr);
1027 do_cleanups (old_chain);
1031 /* Look up an internal variable with name NAME. NAME should not
1032 normally include a dollar sign.
1034 If the specified internal variable does not exist,
1035 the return value is NULL. */
1037 struct internalvar *
1038 lookup_only_internalvar (const char *name)
1040 struct internalvar *var;
1042 for (var = internalvars; var; var = var->next)
1043 if (strcmp (var->name, name) == 0)
1050 /* Create an internal variable with name NAME and with a void value.
1051 NAME should not normally include a dollar sign. */
1053 struct internalvar *
1054 create_internalvar (const char *name)
1056 struct internalvar *var;
1057 var = (struct internalvar *) xmalloc (sizeof (struct internalvar));
1058 var->name = concat (name, (char *)NULL);
1059 var->kind = INTERNALVAR_VOID;
1060 var->next = internalvars;
1065 /* Create an internal variable with name NAME and register FUN as the
1066 function that value_of_internalvar uses to create a value whenever
1067 this variable is referenced. NAME should not normally include a
1070 struct internalvar *
1071 create_internalvar_type_lazy (char *name, internalvar_make_value fun)
1073 struct internalvar *var = create_internalvar (name);
1074 var->kind = INTERNALVAR_MAKE_VALUE;
1075 var->u.make_value = fun;
1079 /* Look up an internal variable with name NAME. NAME should not
1080 normally include a dollar sign.
1082 If the specified internal variable does not exist,
1083 one is created, with a void value. */
1085 struct internalvar *
1086 lookup_internalvar (const char *name)
1088 struct internalvar *var;
1090 var = lookup_only_internalvar (name);
1094 return create_internalvar (name);
1097 /* Return current value of internal variable VAR. For variables that
1098 are not inherently typed, use a value type appropriate for GDBARCH. */
1101 value_of_internalvar (struct gdbarch *gdbarch, struct internalvar *var)
1107 case INTERNALVAR_VOID:
1108 val = allocate_value (builtin_type (gdbarch)->builtin_void);
1111 case INTERNALVAR_FUNCTION:
1112 val = allocate_value (builtin_type (gdbarch)->internal_fn);
1115 case INTERNALVAR_INTEGER:
1116 if (!var->u.integer.type)
1117 val = value_from_longest (builtin_type (gdbarch)->builtin_int,
1118 var->u.integer.val);
1120 val = value_from_longest (var->u.integer.type, var->u.integer.val);
1123 case INTERNALVAR_POINTER:
1124 val = value_from_pointer (var->u.pointer.type, var->u.pointer.val);
1127 case INTERNALVAR_STRING:
1128 val = value_cstring (var->u.string, strlen (var->u.string),
1129 builtin_type (gdbarch)->builtin_char);
1132 case INTERNALVAR_VALUE:
1133 val = value_copy (var->u.value);
1134 if (value_lazy (val))
1135 value_fetch_lazy (val);
1138 case INTERNALVAR_MAKE_VALUE:
1139 val = (*var->u.make_value) (gdbarch, var);
1143 internal_error (__FILE__, __LINE__, "bad kind");
1146 /* Change the VALUE_LVAL to lval_internalvar so that future operations
1147 on this value go back to affect the original internal variable.
1149 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
1150 no underlying modifyable state in the internal variable.
1152 Likewise, if the variable's value is a computed lvalue, we want
1153 references to it to produce another computed lvalue, where
1154 references and assignments actually operate through the
1155 computed value's functions.
1157 This means that internal variables with computed values
1158 behave a little differently from other internal variables:
1159 assignments to them don't just replace the previous value
1160 altogether. At the moment, this seems like the behavior we
1163 if (var->kind != INTERNALVAR_MAKE_VALUE
1164 && val->lval != lval_computed)
1166 VALUE_LVAL (val) = lval_internalvar;
1167 VALUE_INTERNALVAR (val) = var;
1174 get_internalvar_integer (struct internalvar *var, LONGEST *result)
1178 case INTERNALVAR_INTEGER:
1179 *result = var->u.integer.val;
1188 get_internalvar_function (struct internalvar *var,
1189 struct internal_function **result)
1193 case INTERNALVAR_FUNCTION:
1194 *result = var->u.fn.function;
1203 set_internalvar_component (struct internalvar *var, int offset, int bitpos,
1204 int bitsize, struct value *newval)
1210 case INTERNALVAR_VALUE:
1211 addr = value_contents_writeable (var->u.value);
1214 modify_field (value_type (var->u.value), addr + offset,
1215 value_as_long (newval), bitpos, bitsize);
1217 memcpy (addr + offset, value_contents (newval),
1218 TYPE_LENGTH (value_type (newval)));
1222 /* We can never get a component of any other kind. */
1223 internal_error (__FILE__, __LINE__, "set_internalvar_component");
1228 set_internalvar (struct internalvar *var, struct value *val)
1230 enum internalvar_kind new_kind;
1231 union internalvar_data new_data = { 0 };
1233 if (var->kind == INTERNALVAR_FUNCTION && var->u.fn.canonical)
1234 error (_("Cannot overwrite convenience function %s"), var->name);
1236 /* Prepare new contents. */
1237 switch (TYPE_CODE (check_typedef (value_type (val))))
1239 case TYPE_CODE_VOID:
1240 new_kind = INTERNALVAR_VOID;
1243 case TYPE_CODE_INTERNAL_FUNCTION:
1244 gdb_assert (VALUE_LVAL (val) == lval_internalvar);
1245 new_kind = INTERNALVAR_FUNCTION;
1246 get_internalvar_function (VALUE_INTERNALVAR (val),
1247 &new_data.fn.function);
1248 /* Copies created here are never canonical. */
1252 new_kind = INTERNALVAR_INTEGER;
1253 new_data.integer.type = value_type (val);
1254 new_data.integer.val = value_as_long (val);
1258 new_kind = INTERNALVAR_POINTER;
1259 new_data.pointer.type = value_type (val);
1260 new_data.pointer.val = value_as_address (val);
1264 new_kind = INTERNALVAR_VALUE;
1265 new_data.value = value_copy (val);
1266 new_data.value->modifiable = 1;
1268 /* Force the value to be fetched from the target now, to avoid problems
1269 later when this internalvar is referenced and the target is gone or
1271 if (value_lazy (new_data.value))
1272 value_fetch_lazy (new_data.value);
1274 /* Release the value from the value chain to prevent it from being
1275 deleted by free_all_values. From here on this function should not
1276 call error () until new_data is installed into the var->u to avoid
1278 release_value (new_data.value);
1282 /* Clean up old contents. */
1283 clear_internalvar (var);
1286 var->kind = new_kind;
1288 /* End code which must not call error(). */
1292 set_internalvar_integer (struct internalvar *var, LONGEST l)
1294 /* Clean up old contents. */
1295 clear_internalvar (var);
1297 var->kind = INTERNALVAR_INTEGER;
1298 var->u.integer.type = NULL;
1299 var->u.integer.val = l;
1303 set_internalvar_string (struct internalvar *var, const char *string)
1305 /* Clean up old contents. */
1306 clear_internalvar (var);
1308 var->kind = INTERNALVAR_STRING;
1309 var->u.string = xstrdup (string);
1313 set_internalvar_function (struct internalvar *var, struct internal_function *f)
1315 /* Clean up old contents. */
1316 clear_internalvar (var);
1318 var->kind = INTERNALVAR_FUNCTION;
1319 var->u.fn.function = f;
1320 var->u.fn.canonical = 1;
1321 /* Variables installed here are always the canonical version. */
1325 clear_internalvar (struct internalvar *var)
1327 /* Clean up old contents. */
1330 case INTERNALVAR_VALUE:
1331 value_free (var->u.value);
1334 case INTERNALVAR_STRING:
1335 xfree (var->u.string);
1342 /* Reset to void kind. */
1343 var->kind = INTERNALVAR_VOID;
1347 internalvar_name (struct internalvar *var)
1352 static struct internal_function *
1353 create_internal_function (const char *name,
1354 internal_function_fn handler, void *cookie)
1356 struct internal_function *ifn = XNEW (struct internal_function);
1357 ifn->name = xstrdup (name);
1358 ifn->handler = handler;
1359 ifn->cookie = cookie;
1364 value_internal_function_name (struct value *val)
1366 struct internal_function *ifn;
1369 gdb_assert (VALUE_LVAL (val) == lval_internalvar);
1370 result = get_internalvar_function (VALUE_INTERNALVAR (val), &ifn);
1371 gdb_assert (result);
1377 call_internal_function (struct gdbarch *gdbarch,
1378 const struct language_defn *language,
1379 struct value *func, int argc, struct value **argv)
1381 struct internal_function *ifn;
1384 gdb_assert (VALUE_LVAL (func) == lval_internalvar);
1385 result = get_internalvar_function (VALUE_INTERNALVAR (func), &ifn);
1386 gdb_assert (result);
1388 return (*ifn->handler) (gdbarch, language, ifn->cookie, argc, argv);
1391 /* The 'function' command. This does nothing -- it is just a
1392 placeholder to let "help function NAME" work. This is also used as
1393 the implementation of the sub-command that is created when
1394 registering an internal function. */
1396 function_command (char *command, int from_tty)
1401 /* Clean up if an internal function's command is destroyed. */
1403 function_destroyer (struct cmd_list_element *self, void *ignore)
1409 /* Add a new internal function. NAME is the name of the function; DOC
1410 is a documentation string describing the function. HANDLER is
1411 called when the function is invoked. COOKIE is an arbitrary
1412 pointer which is passed to HANDLER and is intended for "user
1415 add_internal_function (const char *name, const char *doc,
1416 internal_function_fn handler, void *cookie)
1418 struct cmd_list_element *cmd;
1419 struct internal_function *ifn;
1420 struct internalvar *var = lookup_internalvar (name);
1422 ifn = create_internal_function (name, handler, cookie);
1423 set_internalvar_function (var, ifn);
1425 cmd = add_cmd (xstrdup (name), no_class, function_command, (char *) doc,
1427 cmd->destroyer = function_destroyer;
1430 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1431 prevent cycles / duplicates. */
1434 preserve_one_value (struct value *value, struct objfile *objfile,
1435 htab_t copied_types)
1437 if (TYPE_OBJFILE (value->type) == objfile)
1438 value->type = copy_type_recursive (objfile, value->type, copied_types);
1440 if (TYPE_OBJFILE (value->enclosing_type) == objfile)
1441 value->enclosing_type = copy_type_recursive (objfile,
1442 value->enclosing_type,
1446 /* Likewise for internal variable VAR. */
1449 preserve_one_internalvar (struct internalvar *var, struct objfile *objfile,
1450 htab_t copied_types)
1454 case INTERNALVAR_INTEGER:
1455 if (var->u.integer.type && TYPE_OBJFILE (var->u.integer.type) == objfile)
1457 = copy_type_recursive (objfile, var->u.integer.type, copied_types);
1460 case INTERNALVAR_POINTER:
1461 if (TYPE_OBJFILE (var->u.pointer.type) == objfile)
1463 = copy_type_recursive (objfile, var->u.pointer.type, copied_types);
1466 case INTERNALVAR_VALUE:
1467 preserve_one_value (var->u.value, objfile, copied_types);
1472 /* Update the internal variables and value history when OBJFILE is
1473 discarded; we must copy the types out of the objfile. New global types
1474 will be created for every convenience variable which currently points to
1475 this objfile's types, and the convenience variables will be adjusted to
1476 use the new global types. */
1479 preserve_values (struct objfile *objfile)
1481 htab_t copied_types;
1482 struct value_history_chunk *cur;
1483 struct internalvar *var;
1487 /* Create the hash table. We allocate on the objfile's obstack, since
1488 it is soon to be deleted. */
1489 copied_types = create_copied_types_hash (objfile);
1491 for (cur = value_history_chain; cur; cur = cur->next)
1492 for (i = 0; i < VALUE_HISTORY_CHUNK; i++)
1494 preserve_one_value (cur->values[i], objfile, copied_types);
1496 for (var = internalvars; var; var = var->next)
1497 preserve_one_internalvar (var, objfile, copied_types);
1499 preserve_python_values (objfile, copied_types);
1501 htab_delete (copied_types);
1505 show_convenience (char *ignore, int from_tty)
1507 struct gdbarch *gdbarch = get_current_arch ();
1508 struct internalvar *var;
1510 struct value_print_options opts;
1512 get_user_print_options (&opts);
1513 for (var = internalvars; var; var = var->next)
1519 printf_filtered (("$%s = "), var->name);
1520 value_print (value_of_internalvar (gdbarch, var), gdb_stdout,
1522 printf_filtered (("\n"));
1525 printf_unfiltered (_("\
1526 No debugger convenience variables now defined.\n\
1527 Convenience variables have names starting with \"$\";\n\
1528 use \"set\" as in \"set $foo = 5\" to define them.\n"));
1531 /* Extract a value as a C number (either long or double).
1532 Knows how to convert fixed values to double, or
1533 floating values to long.
1534 Does not deallocate the value. */
1537 value_as_long (struct value *val)
1539 /* This coerces arrays and functions, which is necessary (e.g.
1540 in disassemble_command). It also dereferences references, which
1541 I suspect is the most logical thing to do. */
1542 val = coerce_array (val);
1543 return unpack_long (value_type (val), value_contents (val));
1547 value_as_double (struct value *val)
1552 foo = unpack_double (value_type (val), value_contents (val), &inv);
1554 error (_("Invalid floating value found in program."));
1558 /* Extract a value as a C pointer. Does not deallocate the value.
1559 Note that val's type may not actually be a pointer; value_as_long
1560 handles all the cases. */
1562 value_as_address (struct value *val)
1564 struct gdbarch *gdbarch = get_type_arch (value_type (val));
1566 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1567 whether we want this to be true eventually. */
1569 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1570 non-address (e.g. argument to "signal", "info break", etc.), or
1571 for pointers to char, in which the low bits *are* significant. */
1572 return gdbarch_addr_bits_remove (gdbarch, value_as_long (val));
1575 /* There are several targets (IA-64, PowerPC, and others) which
1576 don't represent pointers to functions as simply the address of
1577 the function's entry point. For example, on the IA-64, a
1578 function pointer points to a two-word descriptor, generated by
1579 the linker, which contains the function's entry point, and the
1580 value the IA-64 "global pointer" register should have --- to
1581 support position-independent code. The linker generates
1582 descriptors only for those functions whose addresses are taken.
1584 On such targets, it's difficult for GDB to convert an arbitrary
1585 function address into a function pointer; it has to either find
1586 an existing descriptor for that function, or call malloc and
1587 build its own. On some targets, it is impossible for GDB to
1588 build a descriptor at all: the descriptor must contain a jump
1589 instruction; data memory cannot be executed; and code memory
1592 Upon entry to this function, if VAL is a value of type `function'
1593 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1594 value_address (val) is the address of the function. This is what
1595 you'll get if you evaluate an expression like `main'. The call
1596 to COERCE_ARRAY below actually does all the usual unary
1597 conversions, which includes converting values of type `function'
1598 to `pointer to function'. This is the challenging conversion
1599 discussed above. Then, `unpack_long' will convert that pointer
1600 back into an address.
1602 So, suppose the user types `disassemble foo' on an architecture
1603 with a strange function pointer representation, on which GDB
1604 cannot build its own descriptors, and suppose further that `foo'
1605 has no linker-built descriptor. The address->pointer conversion
1606 will signal an error and prevent the command from running, even
1607 though the next step would have been to convert the pointer
1608 directly back into the same address.
1610 The following shortcut avoids this whole mess. If VAL is a
1611 function, just return its address directly. */
1612 if (TYPE_CODE (value_type (val)) == TYPE_CODE_FUNC
1613 || TYPE_CODE (value_type (val)) == TYPE_CODE_METHOD)
1614 return value_address (val);
1616 val = coerce_array (val);
1618 /* Some architectures (e.g. Harvard), map instruction and data
1619 addresses onto a single large unified address space. For
1620 instance: An architecture may consider a large integer in the
1621 range 0x10000000 .. 0x1000ffff to already represent a data
1622 addresses (hence not need a pointer to address conversion) while
1623 a small integer would still need to be converted integer to
1624 pointer to address. Just assume such architectures handle all
1625 integer conversions in a single function. */
1629 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1630 must admonish GDB hackers to make sure its behavior matches the
1631 compiler's, whenever possible.
1633 In general, I think GDB should evaluate expressions the same way
1634 the compiler does. When the user copies an expression out of
1635 their source code and hands it to a `print' command, they should
1636 get the same value the compiler would have computed. Any
1637 deviation from this rule can cause major confusion and annoyance,
1638 and needs to be justified carefully. In other words, GDB doesn't
1639 really have the freedom to do these conversions in clever and
1642 AndrewC pointed out that users aren't complaining about how GDB
1643 casts integers to pointers; they are complaining that they can't
1644 take an address from a disassembly listing and give it to `x/i'.
1645 This is certainly important.
1647 Adding an architecture method like integer_to_address() certainly
1648 makes it possible for GDB to "get it right" in all circumstances
1649 --- the target has complete control over how things get done, so
1650 people can Do The Right Thing for their target without breaking
1651 anyone else. The standard doesn't specify how integers get
1652 converted to pointers; usually, the ABI doesn't either, but
1653 ABI-specific code is a more reasonable place to handle it. */
1655 if (TYPE_CODE (value_type (val)) != TYPE_CODE_PTR
1656 && TYPE_CODE (value_type (val)) != TYPE_CODE_REF
1657 && gdbarch_integer_to_address_p (gdbarch))
1658 return gdbarch_integer_to_address (gdbarch, value_type (val),
1659 value_contents (val));
1661 return unpack_long (value_type (val), value_contents (val));
1665 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1666 as a long, or as a double, assuming the raw data is described
1667 by type TYPE. Knows how to convert different sizes of values
1668 and can convert between fixed and floating point. We don't assume
1669 any alignment for the raw data. Return value is in host byte order.
1671 If you want functions and arrays to be coerced to pointers, and
1672 references to be dereferenced, call value_as_long() instead.
1674 C++: It is assumed that the front-end has taken care of
1675 all matters concerning pointers to members. A pointer
1676 to member which reaches here is considered to be equivalent
1677 to an INT (or some size). After all, it is only an offset. */
1680 unpack_long (struct type *type, const gdb_byte *valaddr)
1682 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
1683 enum type_code code = TYPE_CODE (type);
1684 int len = TYPE_LENGTH (type);
1685 int nosign = TYPE_UNSIGNED (type);
1689 case TYPE_CODE_TYPEDEF:
1690 return unpack_long (check_typedef (type), valaddr);
1691 case TYPE_CODE_ENUM:
1692 case TYPE_CODE_FLAGS:
1693 case TYPE_CODE_BOOL:
1695 case TYPE_CODE_CHAR:
1696 case TYPE_CODE_RANGE:
1697 case TYPE_CODE_MEMBERPTR:
1699 return extract_unsigned_integer (valaddr, len, byte_order);
1701 return extract_signed_integer (valaddr, len, byte_order);
1704 return extract_typed_floating (valaddr, type);
1706 case TYPE_CODE_DECFLOAT:
1707 /* libdecnumber has a function to convert from decimal to integer, but
1708 it doesn't work when the decimal number has a fractional part. */
1709 return decimal_to_doublest (valaddr, len, byte_order);
1713 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1714 whether we want this to be true eventually. */
1715 return extract_typed_address (valaddr, type);
1718 error (_("Value can't be converted to integer."));
1720 return 0; /* Placate lint. */
1723 /* Return a double value from the specified type and address.
1724 INVP points to an int which is set to 0 for valid value,
1725 1 for invalid value (bad float format). In either case,
1726 the returned double is OK to use. Argument is in target
1727 format, result is in host format. */
1730 unpack_double (struct type *type, const gdb_byte *valaddr, int *invp)
1732 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
1733 enum type_code code;
1737 *invp = 0; /* Assume valid. */
1738 CHECK_TYPEDEF (type);
1739 code = TYPE_CODE (type);
1740 len = TYPE_LENGTH (type);
1741 nosign = TYPE_UNSIGNED (type);
1742 if (code == TYPE_CODE_FLT)
1744 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1745 floating-point value was valid (using the macro
1746 INVALID_FLOAT). That test/macro have been removed.
1748 It turns out that only the VAX defined this macro and then
1749 only in a non-portable way. Fixing the portability problem
1750 wouldn't help since the VAX floating-point code is also badly
1751 bit-rotten. The target needs to add definitions for the
1752 methods gdbarch_float_format and gdbarch_double_format - these
1753 exactly describe the target floating-point format. The
1754 problem here is that the corresponding floatformat_vax_f and
1755 floatformat_vax_d values these methods should be set to are
1756 also not defined either. Oops!
1758 Hopefully someone will add both the missing floatformat
1759 definitions and the new cases for floatformat_is_valid (). */
1761 if (!floatformat_is_valid (floatformat_from_type (type), valaddr))
1767 return extract_typed_floating (valaddr, type);
1769 else if (code == TYPE_CODE_DECFLOAT)
1770 return decimal_to_doublest (valaddr, len, byte_order);
1773 /* Unsigned -- be sure we compensate for signed LONGEST. */
1774 return (ULONGEST) unpack_long (type, valaddr);
1778 /* Signed -- we are OK with unpack_long. */
1779 return unpack_long (type, valaddr);
1783 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1784 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1785 We don't assume any alignment for the raw data. Return value is in
1788 If you want functions and arrays to be coerced to pointers, and
1789 references to be dereferenced, call value_as_address() instead.
1791 C++: It is assumed that the front-end has taken care of
1792 all matters concerning pointers to members. A pointer
1793 to member which reaches here is considered to be equivalent
1794 to an INT (or some size). After all, it is only an offset. */
1797 unpack_pointer (struct type *type, const gdb_byte *valaddr)
1799 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1800 whether we want this to be true eventually. */
1801 return unpack_long (type, valaddr);
1805 /* Get the value of the FIELDN'th field (which must be static) of
1806 TYPE. Return NULL if the field doesn't exist or has been
1810 value_static_field (struct type *type, int fieldno)
1812 struct value *retval;
1814 if (TYPE_FIELD_LOC_KIND (type, fieldno) == FIELD_LOC_KIND_PHYSADDR)
1816 retval = value_at_lazy (TYPE_FIELD_TYPE (type, fieldno),
1817 TYPE_FIELD_STATIC_PHYSADDR (type, fieldno));
1821 char *phys_name = TYPE_FIELD_STATIC_PHYSNAME (type, fieldno);
1822 /*TYPE_FIELD_NAME (type, fieldno);*/
1823 struct symbol *sym = lookup_symbol (phys_name, 0, VAR_DOMAIN, 0);
1827 /* With some compilers, e.g. HP aCC, static data members are reported
1828 as non-debuggable symbols */
1829 struct minimal_symbol *msym = lookup_minimal_symbol (phys_name, NULL, NULL);
1834 retval = value_at_lazy (TYPE_FIELD_TYPE (type, fieldno),
1835 SYMBOL_VALUE_ADDRESS (msym));
1840 /* SYM should never have a SYMBOL_CLASS which will require
1841 read_var_value to use the FRAME parameter. */
1842 if (symbol_read_needs_frame (sym))
1843 warning (_("static field's value depends on the current "
1844 "frame - bad debug info?"));
1845 retval = read_var_value (sym, NULL);
1847 if (retval && VALUE_LVAL (retval) == lval_memory)
1848 SET_FIELD_PHYSADDR (TYPE_FIELD (type, fieldno),
1849 value_address (retval));
1854 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1855 You have to be careful here, since the size of the data area for the value
1856 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1857 than the old enclosing type, you have to allocate more space for the data.
1858 The return value is a pointer to the new version of this value structure. */
1861 value_change_enclosing_type (struct value *val, struct type *new_encl_type)
1863 if (TYPE_LENGTH (new_encl_type) > TYPE_LENGTH (value_enclosing_type (val)))
1865 (gdb_byte *) xrealloc (val->contents, TYPE_LENGTH (new_encl_type));
1867 val->enclosing_type = new_encl_type;
1871 /* Given a value ARG1 (offset by OFFSET bytes)
1872 of a struct or union type ARG_TYPE,
1873 extract and return the value of one of its (non-static) fields.
1874 FIELDNO says which field. */
1877 value_primitive_field (struct value *arg1, int offset,
1878 int fieldno, struct type *arg_type)
1883 CHECK_TYPEDEF (arg_type);
1884 type = TYPE_FIELD_TYPE (arg_type, fieldno);
1886 /* Call check_typedef on our type to make sure that, if TYPE
1887 is a TYPE_CODE_TYPEDEF, its length is set to the length
1888 of the target type instead of zero. However, we do not
1889 replace the typedef type by the target type, because we want
1890 to keep the typedef in order to be able to print the type
1891 description correctly. */
1892 check_typedef (type);
1894 /* Handle packed fields */
1896 if (TYPE_FIELD_BITSIZE (arg_type, fieldno))
1898 /* Create a new value for the bitfield, with bitpos and bitsize
1899 set. If possible, arrange offset and bitpos so that we can
1900 do a single aligned read of the size of the containing type.
1901 Otherwise, adjust offset to the byte containing the first
1902 bit. Assume that the address, offset, and embedded offset
1903 are sufficiently aligned. */
1904 int bitpos = TYPE_FIELD_BITPOS (arg_type, fieldno);
1905 int container_bitsize = TYPE_LENGTH (type) * 8;
1907 v = allocate_value_lazy (type);
1908 v->bitsize = TYPE_FIELD_BITSIZE (arg_type, fieldno);
1909 if ((bitpos % container_bitsize) + v->bitsize <= container_bitsize
1910 && TYPE_LENGTH (type) <= (int) sizeof (LONGEST))
1911 v->bitpos = bitpos % container_bitsize;
1913 v->bitpos = bitpos % 8;
1914 v->offset = value_embedded_offset (arg1)
1915 + (bitpos - v->bitpos) / 8;
1917 value_incref (v->parent);
1918 if (!value_lazy (arg1))
1919 value_fetch_lazy (v);
1921 else if (fieldno < TYPE_N_BASECLASSES (arg_type))
1923 /* This field is actually a base subobject, so preserve the
1924 entire object's contents for later references to virtual
1927 /* Lazy register values with offsets are not supported. */
1928 if (VALUE_LVAL (arg1) == lval_register && value_lazy (arg1))
1929 value_fetch_lazy (arg1);
1931 if (value_lazy (arg1))
1932 v = allocate_value_lazy (value_enclosing_type (arg1));
1935 v = allocate_value (value_enclosing_type (arg1));
1936 memcpy (value_contents_all_raw (v), value_contents_all_raw (arg1),
1937 TYPE_LENGTH (value_enclosing_type (arg1)));
1940 v->offset = value_offset (arg1);
1941 v->embedded_offset = (offset + value_embedded_offset (arg1)
1942 + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8);
1946 /* Plain old data member */
1947 offset += TYPE_FIELD_BITPOS (arg_type, fieldno) / 8;
1949 /* Lazy register values with offsets are not supported. */
1950 if (VALUE_LVAL (arg1) == lval_register && value_lazy (arg1))
1951 value_fetch_lazy (arg1);
1953 if (value_lazy (arg1))
1954 v = allocate_value_lazy (type);
1957 v = allocate_value (type);
1958 memcpy (value_contents_raw (v),
1959 value_contents_raw (arg1) + offset,
1960 TYPE_LENGTH (type));
1962 v->offset = (value_offset (arg1) + offset
1963 + value_embedded_offset (arg1));
1965 set_value_component_location (v, arg1);
1966 VALUE_REGNUM (v) = VALUE_REGNUM (arg1);
1967 VALUE_FRAME_ID (v) = VALUE_FRAME_ID (arg1);
1971 /* Given a value ARG1 of a struct or union type,
1972 extract and return the value of one of its (non-static) fields.
1973 FIELDNO says which field. */
1976 value_field (struct value *arg1, int fieldno)
1978 return value_primitive_field (arg1, 0, fieldno, value_type (arg1));
1981 /* Return a non-virtual function as a value.
1982 F is the list of member functions which contains the desired method.
1983 J is an index into F which provides the desired method.
1985 We only use the symbol for its address, so be happy with either a
1986 full symbol or a minimal symbol.
1990 value_fn_field (struct value **arg1p, struct fn_field *f, int j, struct type *type,
1994 struct type *ftype = TYPE_FN_FIELD_TYPE (f, j);
1995 char *physname = TYPE_FN_FIELD_PHYSNAME (f, j);
1997 struct minimal_symbol *msym;
1999 sym = lookup_symbol (physname, 0, VAR_DOMAIN, 0);
2006 gdb_assert (sym == NULL);
2007 msym = lookup_minimal_symbol (physname, NULL, NULL);
2012 v = allocate_value (ftype);
2015 set_value_address (v, BLOCK_START (SYMBOL_BLOCK_VALUE (sym)));
2019 /* The minimal symbol might point to a function descriptor;
2020 resolve it to the actual code address instead. */
2021 struct objfile *objfile = msymbol_objfile (msym);
2022 struct gdbarch *gdbarch = get_objfile_arch (objfile);
2024 set_value_address (v,
2025 gdbarch_convert_from_func_ptr_addr
2026 (gdbarch, SYMBOL_VALUE_ADDRESS (msym), ¤t_target));
2031 if (type != value_type (*arg1p))
2032 *arg1p = value_ind (value_cast (lookup_pointer_type (type),
2033 value_addr (*arg1p)));
2035 /* Move the `this' pointer according to the offset.
2036 VALUE_OFFSET (*arg1p) += offset;
2044 /* Unpack a bitfield of the specified FIELD_TYPE, from the anonymous
2045 object at VALADDR. The bitfield starts at BITPOS bits and contains
2048 Extracting bits depends on endianness of the machine. Compute the
2049 number of least significant bits to discard. For big endian machines,
2050 we compute the total number of bits in the anonymous object, subtract
2051 off the bit count from the MSB of the object to the MSB of the
2052 bitfield, then the size of the bitfield, which leaves the LSB discard
2053 count. For little endian machines, the discard count is simply the
2054 number of bits from the LSB of the anonymous object to the LSB of the
2057 If the field is signed, we also do sign extension. */
2060 unpack_bits_as_long (struct type *field_type, const gdb_byte *valaddr,
2061 int bitpos, int bitsize)
2063 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (field_type));
2069 /* Read the minimum number of bytes required; there may not be
2070 enough bytes to read an entire ULONGEST. */
2071 CHECK_TYPEDEF (field_type);
2073 bytes_read = ((bitpos % 8) + bitsize + 7) / 8;
2075 bytes_read = TYPE_LENGTH (field_type);
2077 val = extract_unsigned_integer (valaddr + bitpos / 8,
2078 bytes_read, byte_order);
2080 /* Extract bits. See comment above. */
2082 if (gdbarch_bits_big_endian (get_type_arch (field_type)))
2083 lsbcount = (bytes_read * 8 - bitpos % 8 - bitsize);
2085 lsbcount = (bitpos % 8);
2088 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
2089 If the field is signed, and is negative, then sign extend. */
2091 if ((bitsize > 0) && (bitsize < 8 * (int) sizeof (val)))
2093 valmask = (((ULONGEST) 1) << bitsize) - 1;
2095 if (!TYPE_UNSIGNED (field_type))
2097 if (val & (valmask ^ (valmask >> 1)))
2106 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
2107 VALADDR. See unpack_bits_as_long for more details. */
2110 unpack_field_as_long (struct type *type, const gdb_byte *valaddr, int fieldno)
2112 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
2113 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
2114 struct type *field_type = TYPE_FIELD_TYPE (type, fieldno);
2116 return unpack_bits_as_long (field_type, valaddr, bitpos, bitsize);
2119 /* Modify the value of a bitfield. ADDR points to a block of memory in
2120 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
2121 is the desired value of the field, in host byte order. BITPOS and BITSIZE
2122 indicate which bits (in target bit order) comprise the bitfield.
2123 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS+BITSIZE <= lbits, and
2124 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
2127 modify_field (struct type *type, gdb_byte *addr,
2128 LONGEST fieldval, int bitpos, int bitsize)
2130 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
2132 ULONGEST mask = (ULONGEST) -1 >> (8 * sizeof (ULONGEST) - bitsize);
2134 /* If a negative fieldval fits in the field in question, chop
2135 off the sign extension bits. */
2136 if ((~fieldval & ~(mask >> 1)) == 0)
2139 /* Warn if value is too big to fit in the field in question. */
2140 if (0 != (fieldval & ~mask))
2142 /* FIXME: would like to include fieldval in the message, but
2143 we don't have a sprintf_longest. */
2144 warning (_("Value does not fit in %d bits."), bitsize);
2146 /* Truncate it, otherwise adjoining fields may be corrupted. */
2150 oword = extract_unsigned_integer (addr, sizeof oword, byte_order);
2152 /* Shifting for bit field depends on endianness of the target machine. */
2153 if (gdbarch_bits_big_endian (get_type_arch (type)))
2154 bitpos = sizeof (oword) * 8 - bitpos - bitsize;
2156 oword &= ~(mask << bitpos);
2157 oword |= fieldval << bitpos;
2159 store_unsigned_integer (addr, sizeof oword, byte_order, oword);
2162 /* Pack NUM into BUF using a target format of TYPE. */
2165 pack_long (gdb_byte *buf, struct type *type, LONGEST num)
2167 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
2170 type = check_typedef (type);
2171 len = TYPE_LENGTH (type);
2173 switch (TYPE_CODE (type))
2176 case TYPE_CODE_CHAR:
2177 case TYPE_CODE_ENUM:
2178 case TYPE_CODE_FLAGS:
2179 case TYPE_CODE_BOOL:
2180 case TYPE_CODE_RANGE:
2181 case TYPE_CODE_MEMBERPTR:
2182 store_signed_integer (buf, len, byte_order, num);
2187 store_typed_address (buf, type, (CORE_ADDR) num);
2191 error (_("Unexpected type (%d) encountered for integer constant."),
2197 /* Convert C numbers into newly allocated values. */
2200 value_from_longest (struct type *type, LONGEST num)
2202 struct value *val = allocate_value (type);
2204 pack_long (value_contents_raw (val), type, num);
2210 /* Create a value representing a pointer of type TYPE to the address
2213 value_from_pointer (struct type *type, CORE_ADDR addr)
2215 struct value *val = allocate_value (type);
2216 store_typed_address (value_contents_raw (val), check_typedef (type), addr);
2221 /* Create a value of type TYPE whose contents come from VALADDR, if it
2222 is non-null, and whose memory address (in the inferior) is
2226 value_from_contents_and_address (struct type *type,
2227 const gdb_byte *valaddr,
2230 struct value *v = allocate_value (type);
2231 if (valaddr == NULL)
2232 set_value_lazy (v, 1);
2234 memcpy (value_contents_raw (v), valaddr, TYPE_LENGTH (type));
2235 set_value_address (v, address);
2236 VALUE_LVAL (v) = lval_memory;
2241 value_from_double (struct type *type, DOUBLEST num)
2243 struct value *val = allocate_value (type);
2244 struct type *base_type = check_typedef (type);
2245 enum type_code code = TYPE_CODE (base_type);
2246 int len = TYPE_LENGTH (base_type);
2248 if (code == TYPE_CODE_FLT)
2250 store_typed_floating (value_contents_raw (val), base_type, num);
2253 error (_("Unexpected type encountered for floating constant."));
2259 value_from_decfloat (struct type *type, const gdb_byte *dec)
2261 struct value *val = allocate_value (type);
2263 memcpy (value_contents_raw (val), dec, TYPE_LENGTH (type));
2269 coerce_ref (struct value *arg)
2271 struct type *value_type_arg_tmp = check_typedef (value_type (arg));
2272 if (TYPE_CODE (value_type_arg_tmp) == TYPE_CODE_REF)
2273 arg = value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp),
2274 unpack_pointer (value_type (arg),
2275 value_contents (arg)));
2280 coerce_array (struct value *arg)
2284 arg = coerce_ref (arg);
2285 type = check_typedef (value_type (arg));
2287 switch (TYPE_CODE (type))
2289 case TYPE_CODE_ARRAY:
2290 if (current_language->c_style_arrays)
2291 arg = value_coerce_array (arg);
2293 case TYPE_CODE_FUNC:
2294 arg = value_coerce_function (arg);
2301 /* Return true if the function returning the specified type is using
2302 the convention of returning structures in memory (passing in the
2303 address as a hidden first parameter). */
2306 using_struct_return (struct gdbarch *gdbarch,
2307 struct type *func_type, struct type *value_type)
2309 enum type_code code = TYPE_CODE (value_type);
2311 if (code == TYPE_CODE_ERROR)
2312 error (_("Function return type unknown."));
2314 if (code == TYPE_CODE_VOID)
2315 /* A void return value is never in memory. See also corresponding
2316 code in "print_return_value". */
2319 /* Probe the architecture for the return-value convention. */
2320 return (gdbarch_return_value (gdbarch, func_type, value_type,
2322 != RETURN_VALUE_REGISTER_CONVENTION);
2325 /* Set the initialized field in a value struct. */
2328 set_value_initialized (struct value *val, int status)
2330 val->initialized = status;
2333 /* Return the initialized field in a value struct. */
2336 value_initialized (struct value *val)
2338 return val->initialized;
2342 _initialize_values (void)
2344 add_cmd ("convenience", no_class, show_convenience, _("\
2345 Debugger convenience (\"$foo\") variables.\n\
2346 These variables are created when you assign them values;\n\
2347 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2349 A few convenience variables are given values automatically:\n\
2350 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2351 \"$__\" holds the contents of the last address examined with \"x\"."),
2354 add_cmd ("values", no_class, show_values,
2355 _("Elements of value history around item number IDX (or last ten)."),
2358 add_com ("init-if-undefined", class_vars, init_if_undefined_command, _("\
2359 Initialize a convenience variable if necessary.\n\
2360 init-if-undefined VARIABLE = EXPRESSION\n\
2361 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2362 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2363 VARIABLE is already initialized."));
2365 add_prefix_cmd ("function", no_class, function_command, _("\
2366 Placeholder command for showing help on convenience functions."),
2367 &functionlist, "function ", 0, &cmdlist);