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 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 /* Actual contents of the value. Target byte-order. NULL or not
200 valid if lazy is nonzero. */
203 /* The number of references to this value. When a value is created,
204 the value chain holds a reference, so REFERENCE_COUNT is 1. If
205 release_value is called, this value is removed from the chain but
206 the caller of release_value now has a reference to this value.
207 The caller must arrange for a call to value_free later. */
211 /* Prototypes for local functions. */
213 static void show_values (char *, int);
215 static void show_convenience (char *, int);
218 /* The value-history records all the values printed
219 by print commands during this session. Each chunk
220 records 60 consecutive values. The first chunk on
221 the chain records the most recent values.
222 The total number of values is in value_history_count. */
224 #define VALUE_HISTORY_CHUNK 60
226 struct value_history_chunk
228 struct value_history_chunk
*next
;
229 struct value
*values
[VALUE_HISTORY_CHUNK
];
232 /* Chain of chunks now in use. */
234 static struct value_history_chunk
*value_history_chain
;
236 static int value_history_count
; /* Abs number of last entry stored */
239 /* List of all value objects currently allocated
240 (except for those released by calls to release_value)
241 This is so they can be freed after each command. */
243 static struct value
*all_values
;
245 /* Allocate a lazy value for type TYPE. Its actual content is
246 "lazily" allocated too: the content field of the return value is
247 NULL; it will be allocated when it is fetched from the target. */
250 allocate_value_lazy (struct type
*type
)
253 struct type
*atype
= check_typedef (type
);
255 val
= (struct value
*) xzalloc (sizeof (struct value
));
256 val
->contents
= NULL
;
257 val
->next
= all_values
;
260 val
->enclosing_type
= type
;
261 VALUE_LVAL (val
) = not_lval
;
262 val
->location
.address
= 0;
263 VALUE_FRAME_ID (val
) = null_frame_id
;
267 VALUE_REGNUM (val
) = -1;
269 val
->optimized_out
= 0;
270 val
->embedded_offset
= 0;
271 val
->pointed_to_offset
= 0;
273 val
->initialized
= 1; /* Default to initialized. */
275 /* Values start out on the all_values chain. */
276 val
->reference_count
= 1;
281 /* Allocate the contents of VAL if it has not been allocated yet. */
284 allocate_value_contents (struct value
*val
)
287 val
->contents
= (gdb_byte
*) xzalloc (TYPE_LENGTH (val
->enclosing_type
));
290 /* Allocate a value and its contents for type TYPE. */
293 allocate_value (struct type
*type
)
295 struct value
*val
= allocate_value_lazy (type
);
296 allocate_value_contents (val
);
301 /* Allocate a value that has the correct length
302 for COUNT repetitions of type TYPE. */
305 allocate_repeat_value (struct type
*type
, int count
)
307 int low_bound
= current_language
->string_lower_bound
; /* ??? */
308 /* FIXME-type-allocation: need a way to free this type when we are
310 struct type
*array_type
311 = lookup_array_range_type (type
, low_bound
, count
+ low_bound
- 1);
312 return allocate_value (array_type
);
316 allocate_computed_value (struct type
*type
,
317 struct lval_funcs
*funcs
,
320 struct value
*v
= allocate_value (type
);
321 VALUE_LVAL (v
) = lval_computed
;
322 v
->location
.computed
.funcs
= funcs
;
323 v
->location
.computed
.closure
= closure
;
324 set_value_lazy (v
, 1);
329 /* Accessor methods. */
332 value_next (struct value
*value
)
338 value_type (struct value
*value
)
343 deprecated_set_value_type (struct value
*value
, struct type
*type
)
349 value_offset (struct value
*value
)
351 return value
->offset
;
354 set_value_offset (struct value
*value
, int offset
)
356 value
->offset
= offset
;
360 value_bitpos (struct value
*value
)
362 return value
->bitpos
;
365 set_value_bitpos (struct value
*value
, int bit
)
371 value_bitsize (struct value
*value
)
373 return value
->bitsize
;
376 set_value_bitsize (struct value
*value
, int bit
)
378 value
->bitsize
= bit
;
382 value_parent (struct value
*value
)
384 return value
->parent
;
388 value_contents_raw (struct value
*value
)
390 allocate_value_contents (value
);
391 return value
->contents
+ value
->embedded_offset
;
395 value_contents_all_raw (struct value
*value
)
397 allocate_value_contents (value
);
398 return value
->contents
;
402 value_enclosing_type (struct value
*value
)
404 return value
->enclosing_type
;
408 value_contents_all (struct value
*value
)
411 value_fetch_lazy (value
);
412 return value
->contents
;
416 value_lazy (struct value
*value
)
422 set_value_lazy (struct value
*value
, int val
)
428 value_contents (struct value
*value
)
430 return value_contents_writeable (value
);
434 value_contents_writeable (struct value
*value
)
437 value_fetch_lazy (value
);
438 return value_contents_raw (value
);
441 /* Return non-zero if VAL1 and VAL2 have the same contents. Note that
442 this function is different from value_equal; in C the operator ==
443 can return 0 even if the two values being compared are equal. */
446 value_contents_equal (struct value
*val1
, struct value
*val2
)
452 type1
= check_typedef (value_type (val1
));
453 type2
= check_typedef (value_type (val2
));
454 len
= TYPE_LENGTH (type1
);
455 if (len
!= TYPE_LENGTH (type2
))
458 return (memcmp (value_contents (val1
), value_contents (val2
), len
) == 0);
462 value_optimized_out (struct value
*value
)
464 return value
->optimized_out
;
468 set_value_optimized_out (struct value
*value
, int val
)
470 value
->optimized_out
= val
;
474 value_embedded_offset (struct value
*value
)
476 return value
->embedded_offset
;
480 set_value_embedded_offset (struct value
*value
, int val
)
482 value
->embedded_offset
= val
;
486 value_pointed_to_offset (struct value
*value
)
488 return value
->pointed_to_offset
;
492 set_value_pointed_to_offset (struct value
*value
, int val
)
494 value
->pointed_to_offset
= val
;
498 value_computed_funcs (struct value
*v
)
500 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
502 return v
->location
.computed
.funcs
;
506 value_computed_closure (struct value
*v
)
508 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
510 return v
->location
.computed
.closure
;
514 deprecated_value_lval_hack (struct value
*value
)
520 value_address (struct value
*value
)
522 if (value
->lval
== lval_internalvar
523 || value
->lval
== lval_internalvar_component
)
525 return value
->location
.address
+ value
->offset
;
529 value_raw_address (struct value
*value
)
531 if (value
->lval
== lval_internalvar
532 || value
->lval
== lval_internalvar_component
)
534 return value
->location
.address
;
538 set_value_address (struct value
*value
, CORE_ADDR addr
)
540 gdb_assert (value
->lval
!= lval_internalvar
541 && value
->lval
!= lval_internalvar_component
);
542 value
->location
.address
= addr
;
545 struct internalvar
**
546 deprecated_value_internalvar_hack (struct value
*value
)
548 return &value
->location
.internalvar
;
552 deprecated_value_frame_id_hack (struct value
*value
)
554 return &value
->frame_id
;
558 deprecated_value_regnum_hack (struct value
*value
)
560 return &value
->regnum
;
564 deprecated_value_modifiable (struct value
*value
)
566 return value
->modifiable
;
569 deprecated_set_value_modifiable (struct value
*value
, int modifiable
)
571 value
->modifiable
= modifiable
;
574 /* Return a mark in the value chain. All values allocated after the
575 mark is obtained (except for those released) are subject to being freed
576 if a subsequent value_free_to_mark is passed the mark. */
583 /* Take a reference to VAL. VAL will not be deallocated until all
584 references are released. */
587 value_incref (struct value
*val
)
589 val
->reference_count
++;
592 /* Release a reference to VAL, which was acquired with value_incref.
593 This function is also called to deallocate values from the value
597 value_free (struct value
*val
)
601 gdb_assert (val
->reference_count
> 0);
602 val
->reference_count
--;
603 if (val
->reference_count
> 0)
606 /* If there's an associated parent value, drop our reference to
608 if (val
->parent
!= NULL
)
609 value_free (val
->parent
);
611 if (VALUE_LVAL (val
) == lval_computed
)
613 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
615 if (funcs
->free_closure
)
616 funcs
->free_closure (val
);
619 xfree (val
->contents
);
624 /* Free all values allocated since MARK was obtained by value_mark
625 (except for those released). */
627 value_free_to_mark (struct value
*mark
)
632 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
640 /* Free all the values that have been allocated (except for those released).
641 Call after each command, successful or not.
642 In practice this is called before each command, which is sufficient. */
645 free_all_values (void)
650 for (val
= all_values
; val
; val
= next
)
659 /* Remove VAL from the chain all_values
660 so it will not be freed automatically. */
663 release_value (struct value
*val
)
667 if (all_values
== val
)
669 all_values
= val
->next
;
673 for (v
= all_values
; v
; v
= v
->next
)
683 /* Release all values up to mark */
685 value_release_to_mark (struct value
*mark
)
690 for (val
= next
= all_values
; next
; next
= next
->next
)
691 if (next
->next
== mark
)
693 all_values
= next
->next
;
701 /* Return a copy of the value ARG.
702 It contains the same contents, for same memory address,
703 but it's a different block of storage. */
706 value_copy (struct value
*arg
)
708 struct type
*encl_type
= value_enclosing_type (arg
);
711 if (value_lazy (arg
))
712 val
= allocate_value_lazy (encl_type
);
714 val
= allocate_value (encl_type
);
715 val
->type
= arg
->type
;
716 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
717 val
->location
= arg
->location
;
718 val
->offset
= arg
->offset
;
719 val
->bitpos
= arg
->bitpos
;
720 val
->bitsize
= arg
->bitsize
;
721 VALUE_FRAME_ID (val
) = VALUE_FRAME_ID (arg
);
722 VALUE_REGNUM (val
) = VALUE_REGNUM (arg
);
723 val
->lazy
= arg
->lazy
;
724 val
->optimized_out
= arg
->optimized_out
;
725 val
->embedded_offset
= value_embedded_offset (arg
);
726 val
->pointed_to_offset
= arg
->pointed_to_offset
;
727 val
->modifiable
= arg
->modifiable
;
728 if (!value_lazy (val
))
730 memcpy (value_contents_all_raw (val
), value_contents_all_raw (arg
),
731 TYPE_LENGTH (value_enclosing_type (arg
)));
734 val
->parent
= arg
->parent
;
736 value_incref (val
->parent
);
737 if (VALUE_LVAL (val
) == lval_computed
)
739 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
741 if (funcs
->copy_closure
)
742 val
->location
.computed
.closure
= funcs
->copy_closure (val
);
748 set_value_component_location (struct value
*component
, struct value
*whole
)
750 if (VALUE_LVAL (whole
) == lval_internalvar
)
751 VALUE_LVAL (component
) = lval_internalvar_component
;
753 VALUE_LVAL (component
) = VALUE_LVAL (whole
);
755 component
->location
= whole
->location
;
756 if (VALUE_LVAL (whole
) == lval_computed
)
758 struct lval_funcs
*funcs
= whole
->location
.computed
.funcs
;
760 if (funcs
->copy_closure
)
761 component
->location
.computed
.closure
= funcs
->copy_closure (whole
);
766 /* Access to the value history. */
768 /* Record a new value in the value history.
769 Returns the absolute history index of the entry.
770 Result of -1 indicates the value was not saved; otherwise it is the
771 value history index of this new item. */
774 record_latest_value (struct value
*val
)
778 /* We don't want this value to have anything to do with the inferior anymore.
779 In particular, "set $1 = 50" should not affect the variable from which
780 the value was taken, and fast watchpoints should be able to assume that
781 a value on the value history never changes. */
782 if (value_lazy (val
))
783 value_fetch_lazy (val
);
784 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
785 from. This is a bit dubious, because then *&$1 does not just return $1
786 but the current contents of that location. c'est la vie... */
790 /* Here we treat value_history_count as origin-zero
791 and applying to the value being stored now. */
793 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
796 struct value_history_chunk
*new
797 = (struct value_history_chunk
*)
798 xmalloc (sizeof (struct value_history_chunk
));
799 memset (new->values
, 0, sizeof new->values
);
800 new->next
= value_history_chain
;
801 value_history_chain
= new;
804 value_history_chain
->values
[i
] = val
;
806 /* Now we regard value_history_count as origin-one
807 and applying to the value just stored. */
809 return ++value_history_count
;
812 /* Return a copy of the value in the history with sequence number NUM. */
815 access_value_history (int num
)
817 struct value_history_chunk
*chunk
;
822 absnum
+= value_history_count
;
827 error (_("The history is empty."));
829 error (_("There is only one value in the history."));
831 error (_("History does not go back to $$%d."), -num
);
833 if (absnum
> value_history_count
)
834 error (_("History has not yet reached $%d."), absnum
);
838 /* Now absnum is always absolute and origin zero. */
840 chunk
= value_history_chain
;
841 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
845 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
849 show_values (char *num_exp
, int from_tty
)
857 /* "show values +" should print from the stored position.
858 "show values <exp>" should print around value number <exp>. */
859 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
860 num
= parse_and_eval_long (num_exp
) - 5;
864 /* "show values" means print the last 10 values. */
865 num
= value_history_count
- 9;
871 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
873 struct value_print_options opts
;
874 val
= access_value_history (i
);
875 printf_filtered (("$%d = "), i
);
876 get_user_print_options (&opts
);
877 value_print (val
, gdb_stdout
, &opts
);
878 printf_filtered (("\n"));
881 /* The next "show values +" should start after what we just printed. */
884 /* Hitting just return after this command should do the same thing as
885 "show values +". If num_exp is null, this is unnecessary, since
886 "show values +" is not useful after "show values". */
887 if (from_tty
&& num_exp
)
894 /* Internal variables. These are variables within the debugger
895 that hold values assigned by debugger commands.
896 The user refers to them with a '$' prefix
897 that does not appear in the variable names stored internally. */
901 struct internalvar
*next
;
904 /* We support various different kinds of content of an internal variable.
905 enum internalvar_kind specifies the kind, and union internalvar_data
906 provides the data associated with this particular kind. */
908 enum internalvar_kind
910 /* The internal variable is empty. */
913 /* The value of the internal variable is provided directly as
914 a GDB value object. */
917 /* A fresh value is computed via a call-back routine on every
918 access to the internal variable. */
919 INTERNALVAR_MAKE_VALUE
,
921 /* The internal variable holds a GDB internal convenience function. */
922 INTERNALVAR_FUNCTION
,
924 /* The variable holds an integer value. */
927 /* The variable holds a pointer value. */
930 /* The variable holds a GDB-provided string. */
935 union internalvar_data
937 /* A value object used with INTERNALVAR_VALUE. */
940 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
941 internalvar_make_value make_value
;
943 /* The internal function used with INTERNALVAR_FUNCTION. */
946 struct internal_function
*function
;
947 /* True if this is the canonical name for the function. */
951 /* An integer value used with INTERNALVAR_INTEGER. */
954 /* If type is non-NULL, it will be used as the type to generate
955 a value for this internal variable. If type is NULL, a default
956 integer type for the architecture is used. */
961 /* A pointer value used with INTERNALVAR_POINTER. */
968 /* A string value used with INTERNALVAR_STRING. */
973 static struct internalvar
*internalvars
;
975 /* If the variable does not already exist create it and give it the value given.
976 If no value is given then the default is zero. */
978 init_if_undefined_command (char* args
, int from_tty
)
980 struct internalvar
* intvar
;
982 /* Parse the expression - this is taken from set_command(). */
983 struct expression
*expr
= parse_expression (args
);
984 register struct cleanup
*old_chain
=
985 make_cleanup (free_current_contents
, &expr
);
987 /* Validate the expression.
988 Was the expression an assignment?
989 Or even an expression at all? */
990 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
991 error (_("Init-if-undefined requires an assignment expression."));
993 /* Extract the variable from the parsed expression.
994 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
995 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
996 error (_("The first parameter to init-if-undefined should be a GDB variable."));
997 intvar
= expr
->elts
[2].internalvar
;
999 /* Only evaluate the expression if the lvalue is void.
1000 This may still fail if the expresssion is invalid. */
1001 if (intvar
->kind
== INTERNALVAR_VOID
)
1002 evaluate_expression (expr
);
1004 do_cleanups (old_chain
);
1008 /* Look up an internal variable with name NAME. NAME should not
1009 normally include a dollar sign.
1011 If the specified internal variable does not exist,
1012 the return value is NULL. */
1014 struct internalvar
*
1015 lookup_only_internalvar (const char *name
)
1017 struct internalvar
*var
;
1019 for (var
= internalvars
; var
; var
= var
->next
)
1020 if (strcmp (var
->name
, name
) == 0)
1027 /* Create an internal variable with name NAME and with a void value.
1028 NAME should not normally include a dollar sign. */
1030 struct internalvar
*
1031 create_internalvar (const char *name
)
1033 struct internalvar
*var
;
1034 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
1035 var
->name
= concat (name
, (char *)NULL
);
1036 var
->kind
= INTERNALVAR_VOID
;
1037 var
->next
= internalvars
;
1042 /* Create an internal variable with name NAME and register FUN as the
1043 function that value_of_internalvar uses to create a value whenever
1044 this variable is referenced. NAME should not normally include a
1047 struct internalvar
*
1048 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
1050 struct internalvar
*var
= create_internalvar (name
);
1051 var
->kind
= INTERNALVAR_MAKE_VALUE
;
1052 var
->u
.make_value
= fun
;
1056 /* Look up an internal variable with name NAME. NAME should not
1057 normally include a dollar sign.
1059 If the specified internal variable does not exist,
1060 one is created, with a void value. */
1062 struct internalvar
*
1063 lookup_internalvar (const char *name
)
1065 struct internalvar
*var
;
1067 var
= lookup_only_internalvar (name
);
1071 return create_internalvar (name
);
1074 /* Return current value of internal variable VAR. For variables that
1075 are not inherently typed, use a value type appropriate for GDBARCH. */
1078 value_of_internalvar (struct gdbarch
*gdbarch
, struct internalvar
*var
)
1084 case INTERNALVAR_VOID
:
1085 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1088 case INTERNALVAR_FUNCTION
:
1089 val
= allocate_value (builtin_type (gdbarch
)->internal_fn
);
1092 case INTERNALVAR_INTEGER
:
1093 if (!var
->u
.integer
.type
)
1094 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
1095 var
->u
.integer
.val
);
1097 val
= value_from_longest (var
->u
.integer
.type
, var
->u
.integer
.val
);
1100 case INTERNALVAR_POINTER
:
1101 val
= value_from_pointer (var
->u
.pointer
.type
, var
->u
.pointer
.val
);
1104 case INTERNALVAR_STRING
:
1105 val
= value_cstring (var
->u
.string
, strlen (var
->u
.string
),
1106 builtin_type (gdbarch
)->builtin_char
);
1109 case INTERNALVAR_VALUE
:
1110 val
= value_copy (var
->u
.value
);
1111 if (value_lazy (val
))
1112 value_fetch_lazy (val
);
1115 case INTERNALVAR_MAKE_VALUE
:
1116 val
= (*var
->u
.make_value
) (gdbarch
, var
);
1120 internal_error (__FILE__
, __LINE__
, "bad kind");
1123 /* Change the VALUE_LVAL to lval_internalvar so that future operations
1124 on this value go back to affect the original internal variable.
1126 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
1127 no underlying modifyable state in the internal variable.
1129 Likewise, if the variable's value is a computed lvalue, we want
1130 references to it to produce another computed lvalue, where
1131 references and assignments actually operate through the
1132 computed value's functions.
1134 This means that internal variables with computed values
1135 behave a little differently from other internal variables:
1136 assignments to them don't just replace the previous value
1137 altogether. At the moment, this seems like the behavior we
1140 if (var
->kind
!= INTERNALVAR_MAKE_VALUE
1141 && val
->lval
!= lval_computed
)
1143 VALUE_LVAL (val
) = lval_internalvar
;
1144 VALUE_INTERNALVAR (val
) = var
;
1151 get_internalvar_integer (struct internalvar
*var
, LONGEST
*result
)
1155 case INTERNALVAR_INTEGER
:
1156 *result
= var
->u
.integer
.val
;
1165 get_internalvar_function (struct internalvar
*var
,
1166 struct internal_function
**result
)
1170 case INTERNALVAR_FUNCTION
:
1171 *result
= var
->u
.fn
.function
;
1180 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1181 int bitsize
, struct value
*newval
)
1187 case INTERNALVAR_VALUE
:
1188 addr
= value_contents_writeable (var
->u
.value
);
1191 modify_field (value_type (var
->u
.value
), addr
+ offset
,
1192 value_as_long (newval
), bitpos
, bitsize
);
1194 memcpy (addr
+ offset
, value_contents (newval
),
1195 TYPE_LENGTH (value_type (newval
)));
1199 /* We can never get a component of any other kind. */
1200 internal_error (__FILE__
, __LINE__
, "set_internalvar_component");
1205 set_internalvar (struct internalvar
*var
, struct value
*val
)
1207 enum internalvar_kind new_kind
;
1208 union internalvar_data new_data
= { 0 };
1210 if (var
->kind
== INTERNALVAR_FUNCTION
&& var
->u
.fn
.canonical
)
1211 error (_("Cannot overwrite convenience function %s"), var
->name
);
1213 /* Prepare new contents. */
1214 switch (TYPE_CODE (check_typedef (value_type (val
))))
1216 case TYPE_CODE_VOID
:
1217 new_kind
= INTERNALVAR_VOID
;
1220 case TYPE_CODE_INTERNAL_FUNCTION
:
1221 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1222 new_kind
= INTERNALVAR_FUNCTION
;
1223 get_internalvar_function (VALUE_INTERNALVAR (val
),
1224 &new_data
.fn
.function
);
1225 /* Copies created here are never canonical. */
1229 new_kind
= INTERNALVAR_INTEGER
;
1230 new_data
.integer
.type
= value_type (val
);
1231 new_data
.integer
.val
= value_as_long (val
);
1235 new_kind
= INTERNALVAR_POINTER
;
1236 new_data
.pointer
.type
= value_type (val
);
1237 new_data
.pointer
.val
= value_as_address (val
);
1241 new_kind
= INTERNALVAR_VALUE
;
1242 new_data
.value
= value_copy (val
);
1243 new_data
.value
->modifiable
= 1;
1245 /* Force the value to be fetched from the target now, to avoid problems
1246 later when this internalvar is referenced and the target is gone or
1248 if (value_lazy (new_data
.value
))
1249 value_fetch_lazy (new_data
.value
);
1251 /* Release the value from the value chain to prevent it from being
1252 deleted by free_all_values. From here on this function should not
1253 call error () until new_data is installed into the var->u to avoid
1255 release_value (new_data
.value
);
1259 /* Clean up old contents. */
1260 clear_internalvar (var
);
1263 var
->kind
= new_kind
;
1265 /* End code which must not call error(). */
1269 set_internalvar_integer (struct internalvar
*var
, LONGEST l
)
1271 /* Clean up old contents. */
1272 clear_internalvar (var
);
1274 var
->kind
= INTERNALVAR_INTEGER
;
1275 var
->u
.integer
.type
= NULL
;
1276 var
->u
.integer
.val
= l
;
1280 set_internalvar_string (struct internalvar
*var
, const char *string
)
1282 /* Clean up old contents. */
1283 clear_internalvar (var
);
1285 var
->kind
= INTERNALVAR_STRING
;
1286 var
->u
.string
= xstrdup (string
);
1290 set_internalvar_function (struct internalvar
*var
, struct internal_function
*f
)
1292 /* Clean up old contents. */
1293 clear_internalvar (var
);
1295 var
->kind
= INTERNALVAR_FUNCTION
;
1296 var
->u
.fn
.function
= f
;
1297 var
->u
.fn
.canonical
= 1;
1298 /* Variables installed here are always the canonical version. */
1302 clear_internalvar (struct internalvar
*var
)
1304 /* Clean up old contents. */
1307 case INTERNALVAR_VALUE
:
1308 value_free (var
->u
.value
);
1311 case INTERNALVAR_STRING
:
1312 xfree (var
->u
.string
);
1319 /* Reset to void kind. */
1320 var
->kind
= INTERNALVAR_VOID
;
1324 internalvar_name (struct internalvar
*var
)
1329 static struct internal_function
*
1330 create_internal_function (const char *name
,
1331 internal_function_fn handler
, void *cookie
)
1333 struct internal_function
*ifn
= XNEW (struct internal_function
);
1334 ifn
->name
= xstrdup (name
);
1335 ifn
->handler
= handler
;
1336 ifn
->cookie
= cookie
;
1341 value_internal_function_name (struct value
*val
)
1343 struct internal_function
*ifn
;
1346 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1347 result
= get_internalvar_function (VALUE_INTERNALVAR (val
), &ifn
);
1348 gdb_assert (result
);
1354 call_internal_function (struct gdbarch
*gdbarch
,
1355 const struct language_defn
*language
,
1356 struct value
*func
, int argc
, struct value
**argv
)
1358 struct internal_function
*ifn
;
1361 gdb_assert (VALUE_LVAL (func
) == lval_internalvar
);
1362 result
= get_internalvar_function (VALUE_INTERNALVAR (func
), &ifn
);
1363 gdb_assert (result
);
1365 return (*ifn
->handler
) (gdbarch
, language
, ifn
->cookie
, argc
, argv
);
1368 /* The 'function' command. This does nothing -- it is just a
1369 placeholder to let "help function NAME" work. This is also used as
1370 the implementation of the sub-command that is created when
1371 registering an internal function. */
1373 function_command (char *command
, int from_tty
)
1378 /* Clean up if an internal function's command is destroyed. */
1380 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1386 /* Add a new internal function. NAME is the name of the function; DOC
1387 is a documentation string describing the function. HANDLER is
1388 called when the function is invoked. COOKIE is an arbitrary
1389 pointer which is passed to HANDLER and is intended for "user
1392 add_internal_function (const char *name
, const char *doc
,
1393 internal_function_fn handler
, void *cookie
)
1395 struct cmd_list_element
*cmd
;
1396 struct internal_function
*ifn
;
1397 struct internalvar
*var
= lookup_internalvar (name
);
1399 ifn
= create_internal_function (name
, handler
, cookie
);
1400 set_internalvar_function (var
, ifn
);
1402 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1404 cmd
->destroyer
= function_destroyer
;
1407 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1408 prevent cycles / duplicates. */
1411 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1412 htab_t copied_types
)
1414 if (TYPE_OBJFILE (value
->type
) == objfile
)
1415 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1417 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1418 value
->enclosing_type
= copy_type_recursive (objfile
,
1419 value
->enclosing_type
,
1423 /* Likewise for internal variable VAR. */
1426 preserve_one_internalvar (struct internalvar
*var
, struct objfile
*objfile
,
1427 htab_t copied_types
)
1431 case INTERNALVAR_INTEGER
:
1432 if (var
->u
.integer
.type
&& TYPE_OBJFILE (var
->u
.integer
.type
) == objfile
)
1434 = copy_type_recursive (objfile
, var
->u
.integer
.type
, copied_types
);
1437 case INTERNALVAR_POINTER
:
1438 if (TYPE_OBJFILE (var
->u
.pointer
.type
) == objfile
)
1440 = copy_type_recursive (objfile
, var
->u
.pointer
.type
, copied_types
);
1443 case INTERNALVAR_VALUE
:
1444 preserve_one_value (var
->u
.value
, objfile
, copied_types
);
1449 /* Update the internal variables and value history when OBJFILE is
1450 discarded; we must copy the types out of the objfile. New global types
1451 will be created for every convenience variable which currently points to
1452 this objfile's types, and the convenience variables will be adjusted to
1453 use the new global types. */
1456 preserve_values (struct objfile
*objfile
)
1458 htab_t copied_types
;
1459 struct value_history_chunk
*cur
;
1460 struct internalvar
*var
;
1464 /* Create the hash table. We allocate on the objfile's obstack, since
1465 it is soon to be deleted. */
1466 copied_types
= create_copied_types_hash (objfile
);
1468 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1469 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1471 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1473 for (var
= internalvars
; var
; var
= var
->next
)
1474 preserve_one_internalvar (var
, objfile
, copied_types
);
1476 preserve_python_values (objfile
, copied_types
);
1478 htab_delete (copied_types
);
1482 show_convenience (char *ignore
, int from_tty
)
1484 struct gdbarch
*gdbarch
= get_current_arch ();
1485 struct internalvar
*var
;
1487 struct value_print_options opts
;
1489 get_user_print_options (&opts
);
1490 for (var
= internalvars
; var
; var
= var
->next
)
1496 printf_filtered (("$%s = "), var
->name
);
1497 value_print (value_of_internalvar (gdbarch
, var
), gdb_stdout
,
1499 printf_filtered (("\n"));
1502 printf_unfiltered (_("\
1503 No debugger convenience variables now defined.\n\
1504 Convenience variables have names starting with \"$\";\n\
1505 use \"set\" as in \"set $foo = 5\" to define them.\n"));
1508 /* Extract a value as a C number (either long or double).
1509 Knows how to convert fixed values to double, or
1510 floating values to long.
1511 Does not deallocate the value. */
1514 value_as_long (struct value
*val
)
1516 /* This coerces arrays and functions, which is necessary (e.g.
1517 in disassemble_command). It also dereferences references, which
1518 I suspect is the most logical thing to do. */
1519 val
= coerce_array (val
);
1520 return unpack_long (value_type (val
), value_contents (val
));
1524 value_as_double (struct value
*val
)
1529 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1531 error (_("Invalid floating value found in program."));
1535 /* Extract a value as a C pointer. Does not deallocate the value.
1536 Note that val's type may not actually be a pointer; value_as_long
1537 handles all the cases. */
1539 value_as_address (struct value
*val
)
1541 struct gdbarch
*gdbarch
= get_type_arch (value_type (val
));
1543 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1544 whether we want this to be true eventually. */
1546 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1547 non-address (e.g. argument to "signal", "info break", etc.), or
1548 for pointers to char, in which the low bits *are* significant. */
1549 return gdbarch_addr_bits_remove (gdbarch
, value_as_long (val
));
1552 /* There are several targets (IA-64, PowerPC, and others) which
1553 don't represent pointers to functions as simply the address of
1554 the function's entry point. For example, on the IA-64, a
1555 function pointer points to a two-word descriptor, generated by
1556 the linker, which contains the function's entry point, and the
1557 value the IA-64 "global pointer" register should have --- to
1558 support position-independent code. The linker generates
1559 descriptors only for those functions whose addresses are taken.
1561 On such targets, it's difficult for GDB to convert an arbitrary
1562 function address into a function pointer; it has to either find
1563 an existing descriptor for that function, or call malloc and
1564 build its own. On some targets, it is impossible for GDB to
1565 build a descriptor at all: the descriptor must contain a jump
1566 instruction; data memory cannot be executed; and code memory
1569 Upon entry to this function, if VAL is a value of type `function'
1570 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1571 value_address (val) is the address of the function. This is what
1572 you'll get if you evaluate an expression like `main'. The call
1573 to COERCE_ARRAY below actually does all the usual unary
1574 conversions, which includes converting values of type `function'
1575 to `pointer to function'. This is the challenging conversion
1576 discussed above. Then, `unpack_long' will convert that pointer
1577 back into an address.
1579 So, suppose the user types `disassemble foo' on an architecture
1580 with a strange function pointer representation, on which GDB
1581 cannot build its own descriptors, and suppose further that `foo'
1582 has no linker-built descriptor. The address->pointer conversion
1583 will signal an error and prevent the command from running, even
1584 though the next step would have been to convert the pointer
1585 directly back into the same address.
1587 The following shortcut avoids this whole mess. If VAL is a
1588 function, just return its address directly. */
1589 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
1590 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
1591 return value_address (val
);
1593 val
= coerce_array (val
);
1595 /* Some architectures (e.g. Harvard), map instruction and data
1596 addresses onto a single large unified address space. For
1597 instance: An architecture may consider a large integer in the
1598 range 0x10000000 .. 0x1000ffff to already represent a data
1599 addresses (hence not need a pointer to address conversion) while
1600 a small integer would still need to be converted integer to
1601 pointer to address. Just assume such architectures handle all
1602 integer conversions in a single function. */
1606 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1607 must admonish GDB hackers to make sure its behavior matches the
1608 compiler's, whenever possible.
1610 In general, I think GDB should evaluate expressions the same way
1611 the compiler does. When the user copies an expression out of
1612 their source code and hands it to a `print' command, they should
1613 get the same value the compiler would have computed. Any
1614 deviation from this rule can cause major confusion and annoyance,
1615 and needs to be justified carefully. In other words, GDB doesn't
1616 really have the freedom to do these conversions in clever and
1619 AndrewC pointed out that users aren't complaining about how GDB
1620 casts integers to pointers; they are complaining that they can't
1621 take an address from a disassembly listing and give it to `x/i'.
1622 This is certainly important.
1624 Adding an architecture method like integer_to_address() certainly
1625 makes it possible for GDB to "get it right" in all circumstances
1626 --- the target has complete control over how things get done, so
1627 people can Do The Right Thing for their target without breaking
1628 anyone else. The standard doesn't specify how integers get
1629 converted to pointers; usually, the ABI doesn't either, but
1630 ABI-specific code is a more reasonable place to handle it. */
1632 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
1633 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
1634 && gdbarch_integer_to_address_p (gdbarch
))
1635 return gdbarch_integer_to_address (gdbarch
, value_type (val
),
1636 value_contents (val
));
1638 return unpack_long (value_type (val
), value_contents (val
));
1642 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1643 as a long, or as a double, assuming the raw data is described
1644 by type TYPE. Knows how to convert different sizes of values
1645 and can convert between fixed and floating point. We don't assume
1646 any alignment for the raw data. Return value is in host byte order.
1648 If you want functions and arrays to be coerced to pointers, and
1649 references to be dereferenced, call value_as_long() instead.
1651 C++: It is assumed that the front-end has taken care of
1652 all matters concerning pointers to members. A pointer
1653 to member which reaches here is considered to be equivalent
1654 to an INT (or some size). After all, it is only an offset. */
1657 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
1659 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1660 enum type_code code
= TYPE_CODE (type
);
1661 int len
= TYPE_LENGTH (type
);
1662 int nosign
= TYPE_UNSIGNED (type
);
1666 case TYPE_CODE_TYPEDEF
:
1667 return unpack_long (check_typedef (type
), valaddr
);
1668 case TYPE_CODE_ENUM
:
1669 case TYPE_CODE_FLAGS
:
1670 case TYPE_CODE_BOOL
:
1672 case TYPE_CODE_CHAR
:
1673 case TYPE_CODE_RANGE
:
1674 case TYPE_CODE_MEMBERPTR
:
1676 return extract_unsigned_integer (valaddr
, len
, byte_order
);
1678 return extract_signed_integer (valaddr
, len
, byte_order
);
1681 return extract_typed_floating (valaddr
, type
);
1683 case TYPE_CODE_DECFLOAT
:
1684 /* libdecnumber has a function to convert from decimal to integer, but
1685 it doesn't work when the decimal number has a fractional part. */
1686 return decimal_to_doublest (valaddr
, len
, byte_order
);
1690 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1691 whether we want this to be true eventually. */
1692 return extract_typed_address (valaddr
, type
);
1695 error (_("Value can't be converted to integer."));
1697 return 0; /* Placate lint. */
1700 /* Return a double value from the specified type and address.
1701 INVP points to an int which is set to 0 for valid value,
1702 1 for invalid value (bad float format). In either case,
1703 the returned double is OK to use. Argument is in target
1704 format, result is in host format. */
1707 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
1709 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1710 enum type_code code
;
1714 *invp
= 0; /* Assume valid. */
1715 CHECK_TYPEDEF (type
);
1716 code
= TYPE_CODE (type
);
1717 len
= TYPE_LENGTH (type
);
1718 nosign
= TYPE_UNSIGNED (type
);
1719 if (code
== TYPE_CODE_FLT
)
1721 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1722 floating-point value was valid (using the macro
1723 INVALID_FLOAT). That test/macro have been removed.
1725 It turns out that only the VAX defined this macro and then
1726 only in a non-portable way. Fixing the portability problem
1727 wouldn't help since the VAX floating-point code is also badly
1728 bit-rotten. The target needs to add definitions for the
1729 methods gdbarch_float_format and gdbarch_double_format - these
1730 exactly describe the target floating-point format. The
1731 problem here is that the corresponding floatformat_vax_f and
1732 floatformat_vax_d values these methods should be set to are
1733 also not defined either. Oops!
1735 Hopefully someone will add both the missing floatformat
1736 definitions and the new cases for floatformat_is_valid (). */
1738 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
1744 return extract_typed_floating (valaddr
, type
);
1746 else if (code
== TYPE_CODE_DECFLOAT
)
1747 return decimal_to_doublest (valaddr
, len
, byte_order
);
1750 /* Unsigned -- be sure we compensate for signed LONGEST. */
1751 return (ULONGEST
) unpack_long (type
, valaddr
);
1755 /* Signed -- we are OK with unpack_long. */
1756 return unpack_long (type
, valaddr
);
1760 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1761 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1762 We don't assume any alignment for the raw data. Return value is in
1765 If you want functions and arrays to be coerced to pointers, and
1766 references to be dereferenced, call value_as_address() instead.
1768 C++: It is assumed that the front-end has taken care of
1769 all matters concerning pointers to members. A pointer
1770 to member which reaches here is considered to be equivalent
1771 to an INT (or some size). After all, it is only an offset. */
1774 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
1776 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1777 whether we want this to be true eventually. */
1778 return unpack_long (type
, valaddr
);
1782 /* Get the value of the FIELDN'th field (which must be static) of
1783 TYPE. Return NULL if the field doesn't exist or has been
1787 value_static_field (struct type
*type
, int fieldno
)
1789 struct value
*retval
;
1791 if (TYPE_FIELD_LOC_KIND (type
, fieldno
) == FIELD_LOC_KIND_PHYSADDR
)
1793 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1794 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1798 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1799 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1802 /* With some compilers, e.g. HP aCC, static data members are reported
1803 as non-debuggable symbols */
1804 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
, NULL
, NULL
);
1809 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1810 SYMBOL_VALUE_ADDRESS (msym
));
1815 /* SYM should never have a SYMBOL_CLASS which will require
1816 read_var_value to use the FRAME parameter. */
1817 if (symbol_read_needs_frame (sym
))
1818 warning (_("static field's value depends on the current "
1819 "frame - bad debug info?"));
1820 retval
= read_var_value (sym
, NULL
);
1822 if (retval
&& VALUE_LVAL (retval
) == lval_memory
)
1823 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
),
1824 value_address (retval
));
1829 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1830 You have to be careful here, since the size of the data area for the value
1831 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1832 than the old enclosing type, you have to allocate more space for the data.
1833 The return value is a pointer to the new version of this value structure. */
1836 value_change_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
1838 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
1840 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
1842 val
->enclosing_type
= new_encl_type
;
1846 /* Given a value ARG1 (offset by OFFSET bytes)
1847 of a struct or union type ARG_TYPE,
1848 extract and return the value of one of its (non-static) fields.
1849 FIELDNO says which field. */
1852 value_primitive_field (struct value
*arg1
, int offset
,
1853 int fieldno
, struct type
*arg_type
)
1858 CHECK_TYPEDEF (arg_type
);
1859 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
1861 /* Handle packed fields */
1863 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
1865 /* Create a new value for the bitfield, with bitpos and bitsize
1866 set. If possible, arrange offset and bitpos so that we can
1867 do a single aligned read of the size of the containing type.
1868 Otherwise, adjust offset to the byte containing the first
1869 bit. Assume that the address, offset, and embedded offset
1870 are sufficiently aligned. */
1871 int bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
);
1872 int container_bitsize
= TYPE_LENGTH (type
) * 8;
1874 v
= allocate_value_lazy (type
);
1875 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
1876 if ((bitpos
% container_bitsize
) + v
->bitsize
<= container_bitsize
1877 && TYPE_LENGTH (type
) <= (int) sizeof (LONGEST
))
1878 v
->bitpos
= bitpos
% container_bitsize
;
1880 v
->bitpos
= bitpos
% 8;
1881 v
->offset
= value_embedded_offset (arg1
)
1882 + (bitpos
- v
->bitpos
) / 8;
1884 value_incref (v
->parent
);
1885 if (!value_lazy (arg1
))
1886 value_fetch_lazy (v
);
1888 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
1890 /* This field is actually a base subobject, so preserve the
1891 entire object's contents for later references to virtual
1894 /* Lazy register values with offsets are not supported. */
1895 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1896 value_fetch_lazy (arg1
);
1898 if (value_lazy (arg1
))
1899 v
= allocate_value_lazy (value_enclosing_type (arg1
));
1902 v
= allocate_value (value_enclosing_type (arg1
));
1903 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
1904 TYPE_LENGTH (value_enclosing_type (arg1
)));
1907 v
->offset
= value_offset (arg1
);
1908 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
1909 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
1913 /* Plain old data member */
1914 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1916 /* Lazy register values with offsets are not supported. */
1917 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1918 value_fetch_lazy (arg1
);
1920 if (value_lazy (arg1
))
1921 v
= allocate_value_lazy (type
);
1924 v
= allocate_value (type
);
1925 memcpy (value_contents_raw (v
),
1926 value_contents_raw (arg1
) + offset
,
1927 TYPE_LENGTH (type
));
1929 v
->offset
= (value_offset (arg1
) + offset
1930 + value_embedded_offset (arg1
));
1932 set_value_component_location (v
, arg1
);
1933 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
1934 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
1938 /* Given a value ARG1 of a struct or union type,
1939 extract and return the value of one of its (non-static) fields.
1940 FIELDNO says which field. */
1943 value_field (struct value
*arg1
, int fieldno
)
1945 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
1948 /* Return a non-virtual function as a value.
1949 F is the list of member functions which contains the desired method.
1950 J is an index into F which provides the desired method.
1952 We only use the symbol for its address, so be happy with either a
1953 full symbol or a minimal symbol.
1957 value_fn_field (struct value
**arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
1961 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
1962 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
1964 struct minimal_symbol
*msym
;
1966 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
1973 gdb_assert (sym
== NULL
);
1974 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
1979 v
= allocate_value (ftype
);
1982 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
1986 /* The minimal symbol might point to a function descriptor;
1987 resolve it to the actual code address instead. */
1988 struct objfile
*objfile
= msymbol_objfile (msym
);
1989 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
1991 set_value_address (v
,
1992 gdbarch_convert_from_func_ptr_addr
1993 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
1998 if (type
!= value_type (*arg1p
))
1999 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
2000 value_addr (*arg1p
)));
2002 /* Move the `this' pointer according to the offset.
2003 VALUE_OFFSET (*arg1p) += offset;
2011 /* Unpack a bitfield of the specified FIELD_TYPE, from the anonymous
2012 object at VALADDR. The bitfield starts at BITPOS bits and contains
2015 Extracting bits depends on endianness of the machine. Compute the
2016 number of least significant bits to discard. For big endian machines,
2017 we compute the total number of bits in the anonymous object, subtract
2018 off the bit count from the MSB of the object to the MSB of the
2019 bitfield, then the size of the bitfield, which leaves the LSB discard
2020 count. For little endian machines, the discard count is simply the
2021 number of bits from the LSB of the anonymous object to the LSB of the
2024 If the field is signed, we also do sign extension. */
2027 unpack_bits_as_long (struct type
*field_type
, const gdb_byte
*valaddr
,
2028 int bitpos
, int bitsize
)
2030 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (field_type
));
2036 /* Read the minimum number of bytes required; there may not be
2037 enough bytes to read an entire ULONGEST. */
2038 CHECK_TYPEDEF (field_type
);
2040 bytes_read
= ((bitpos
% 8) + bitsize
+ 7) / 8;
2042 bytes_read
= TYPE_LENGTH (field_type
);
2044 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8,
2045 bytes_read
, byte_order
);
2047 /* Extract bits. See comment above. */
2049 if (gdbarch_bits_big_endian (get_type_arch (field_type
)))
2050 lsbcount
= (bytes_read
* 8 - bitpos
% 8 - bitsize
);
2052 lsbcount
= (bitpos
% 8);
2055 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
2056 If the field is signed, and is negative, then sign extend. */
2058 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
2060 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
2062 if (!TYPE_UNSIGNED (field_type
))
2064 if (val
& (valmask
^ (valmask
>> 1)))
2073 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
2074 VALADDR. See unpack_bits_as_long for more details. */
2077 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
2079 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
2080 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
2081 struct type
*field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
2083 return unpack_bits_as_long (field_type
, valaddr
, bitpos
, bitsize
);
2086 /* Modify the value of a bitfield. ADDR points to a block of memory in
2087 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
2088 is the desired value of the field, in host byte order. BITPOS and BITSIZE
2089 indicate which bits (in target bit order) comprise the bitfield.
2090 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS+BITSIZE <= lbits, and
2091 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
2094 modify_field (struct type
*type
, gdb_byte
*addr
,
2095 LONGEST fieldval
, int bitpos
, int bitsize
)
2097 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2099 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
2101 /* If a negative fieldval fits in the field in question, chop
2102 off the sign extension bits. */
2103 if ((~fieldval
& ~(mask
>> 1)) == 0)
2106 /* Warn if value is too big to fit in the field in question. */
2107 if (0 != (fieldval
& ~mask
))
2109 /* FIXME: would like to include fieldval in the message, but
2110 we don't have a sprintf_longest. */
2111 warning (_("Value does not fit in %d bits."), bitsize
);
2113 /* Truncate it, otherwise adjoining fields may be corrupted. */
2117 oword
= extract_unsigned_integer (addr
, sizeof oword
, byte_order
);
2119 /* Shifting for bit field depends on endianness of the target machine. */
2120 if (gdbarch_bits_big_endian (get_type_arch (type
)))
2121 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
2123 oword
&= ~(mask
<< bitpos
);
2124 oword
|= fieldval
<< bitpos
;
2126 store_unsigned_integer (addr
, sizeof oword
, byte_order
, oword
);
2129 /* Pack NUM into BUF using a target format of TYPE. */
2132 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
2134 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2137 type
= check_typedef (type
);
2138 len
= TYPE_LENGTH (type
);
2140 switch (TYPE_CODE (type
))
2143 case TYPE_CODE_CHAR
:
2144 case TYPE_CODE_ENUM
:
2145 case TYPE_CODE_FLAGS
:
2146 case TYPE_CODE_BOOL
:
2147 case TYPE_CODE_RANGE
:
2148 case TYPE_CODE_MEMBERPTR
:
2149 store_signed_integer (buf
, len
, byte_order
, num
);
2154 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2158 error (_("Unexpected type (%d) encountered for integer constant."),
2164 /* Convert C numbers into newly allocated values. */
2167 value_from_longest (struct type
*type
, LONGEST num
)
2169 struct value
*val
= allocate_value (type
);
2171 pack_long (value_contents_raw (val
), type
, num
);
2177 /* Create a value representing a pointer of type TYPE to the address
2180 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
2182 struct value
*val
= allocate_value (type
);
2183 store_typed_address (value_contents_raw (val
), check_typedef (type
), addr
);
2188 /* Create a value of type TYPE whose contents come from VALADDR, if it
2189 is non-null, and whose memory address (in the inferior) is
2193 value_from_contents_and_address (struct type
*type
,
2194 const gdb_byte
*valaddr
,
2197 struct value
*v
= allocate_value (type
);
2198 if (valaddr
== NULL
)
2199 set_value_lazy (v
, 1);
2201 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
2202 set_value_address (v
, address
);
2203 VALUE_LVAL (v
) = lval_memory
;
2208 value_from_double (struct type
*type
, DOUBLEST num
)
2210 struct value
*val
= allocate_value (type
);
2211 struct type
*base_type
= check_typedef (type
);
2212 enum type_code code
= TYPE_CODE (base_type
);
2213 int len
= TYPE_LENGTH (base_type
);
2215 if (code
== TYPE_CODE_FLT
)
2217 store_typed_floating (value_contents_raw (val
), base_type
, num
);
2220 error (_("Unexpected type encountered for floating constant."));
2226 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
2228 struct value
*val
= allocate_value (type
);
2230 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
2236 coerce_ref (struct value
*arg
)
2238 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
2239 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
2240 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
2241 unpack_pointer (value_type (arg
),
2242 value_contents (arg
)));
2247 coerce_array (struct value
*arg
)
2251 arg
= coerce_ref (arg
);
2252 type
= check_typedef (value_type (arg
));
2254 switch (TYPE_CODE (type
))
2256 case TYPE_CODE_ARRAY
:
2257 if (current_language
->c_style_arrays
)
2258 arg
= value_coerce_array (arg
);
2260 case TYPE_CODE_FUNC
:
2261 arg
= value_coerce_function (arg
);
2268 /* Return true if the function returning the specified type is using
2269 the convention of returning structures in memory (passing in the
2270 address as a hidden first parameter). */
2273 using_struct_return (struct gdbarch
*gdbarch
,
2274 struct type
*func_type
, struct type
*value_type
)
2276 enum type_code code
= TYPE_CODE (value_type
);
2278 if (code
== TYPE_CODE_ERROR
)
2279 error (_("Function return type unknown."));
2281 if (code
== TYPE_CODE_VOID
)
2282 /* A void return value is never in memory. See also corresponding
2283 code in "print_return_value". */
2286 /* Probe the architecture for the return-value convention. */
2287 return (gdbarch_return_value (gdbarch
, func_type
, value_type
,
2289 != RETURN_VALUE_REGISTER_CONVENTION
);
2292 /* Set the initialized field in a value struct. */
2295 set_value_initialized (struct value
*val
, int status
)
2297 val
->initialized
= status
;
2300 /* Return the initialized field in a value struct. */
2303 value_initialized (struct value
*val
)
2305 return val
->initialized
;
2309 _initialize_values (void)
2311 add_cmd ("convenience", no_class
, show_convenience
, _("\
2312 Debugger convenience (\"$foo\") variables.\n\
2313 These variables are created when you assign them values;\n\
2314 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2316 A few convenience variables are given values automatically:\n\
2317 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2318 \"$__\" holds the contents of the last address examined with \"x\"."),
2321 add_cmd ("values", no_class
, show_values
,
2322 _("Elements of value history around item number IDX (or last ten)."),
2325 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2326 Initialize a convenience variable if necessary.\n\
2327 init-if-undefined VARIABLE = EXPRESSION\n\
2328 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2329 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2330 VARIABLE is already initialized."));
2332 add_prefix_cmd ("function", no_class
, function_command
, _("\
2333 Placeholder command for showing help on convenience functions."),
2334 &functionlist
, "function ", 0, &cmdlist
);