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 Called after each command, successful or not. */
644 free_all_values (void)
649 for (val
= all_values
; val
; val
= next
)
658 /* Remove VAL from the chain all_values
659 so it will not be freed automatically. */
662 release_value (struct value
*val
)
666 if (all_values
== val
)
668 all_values
= val
->next
;
672 for (v
= all_values
; v
; v
= v
->next
)
682 /* Release all values up to mark */
684 value_release_to_mark (struct value
*mark
)
689 for (val
= next
= all_values
; next
; next
= next
->next
)
690 if (next
->next
== mark
)
692 all_values
= next
->next
;
700 /* Return a copy of the value ARG.
701 It contains the same contents, for same memory address,
702 but it's a different block of storage. */
705 value_copy (struct value
*arg
)
707 struct type
*encl_type
= value_enclosing_type (arg
);
710 if (value_lazy (arg
))
711 val
= allocate_value_lazy (encl_type
);
713 val
= allocate_value (encl_type
);
714 val
->type
= arg
->type
;
715 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
716 val
->location
= arg
->location
;
717 val
->offset
= arg
->offset
;
718 val
->bitpos
= arg
->bitpos
;
719 val
->bitsize
= arg
->bitsize
;
720 VALUE_FRAME_ID (val
) = VALUE_FRAME_ID (arg
);
721 VALUE_REGNUM (val
) = VALUE_REGNUM (arg
);
722 val
->lazy
= arg
->lazy
;
723 val
->optimized_out
= arg
->optimized_out
;
724 val
->embedded_offset
= value_embedded_offset (arg
);
725 val
->pointed_to_offset
= arg
->pointed_to_offset
;
726 val
->modifiable
= arg
->modifiable
;
727 if (!value_lazy (val
))
729 memcpy (value_contents_all_raw (val
), value_contents_all_raw (arg
),
730 TYPE_LENGTH (value_enclosing_type (arg
)));
733 val
->parent
= arg
->parent
;
735 value_incref (val
->parent
);
736 if (VALUE_LVAL (val
) == lval_computed
)
738 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
740 if (funcs
->copy_closure
)
741 val
->location
.computed
.closure
= funcs
->copy_closure (val
);
747 set_value_component_location (struct value
*component
, struct value
*whole
)
749 if (VALUE_LVAL (whole
) == lval_internalvar
)
750 VALUE_LVAL (component
) = lval_internalvar_component
;
752 VALUE_LVAL (component
) = VALUE_LVAL (whole
);
754 component
->location
= whole
->location
;
755 if (VALUE_LVAL (whole
) == lval_computed
)
757 struct lval_funcs
*funcs
= whole
->location
.computed
.funcs
;
759 if (funcs
->copy_closure
)
760 component
->location
.computed
.closure
= funcs
->copy_closure (whole
);
765 /* Access to the value history. */
767 /* Record a new value in the value history.
768 Returns the absolute history index of the entry.
769 Result of -1 indicates the value was not saved; otherwise it is the
770 value history index of this new item. */
773 record_latest_value (struct value
*val
)
777 /* We don't want this value to have anything to do with the inferior anymore.
778 In particular, "set $1 = 50" should not affect the variable from which
779 the value was taken, and fast watchpoints should be able to assume that
780 a value on the value history never changes. */
781 if (value_lazy (val
))
782 value_fetch_lazy (val
);
783 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
784 from. This is a bit dubious, because then *&$1 does not just return $1
785 but the current contents of that location. c'est la vie... */
789 /* Here we treat value_history_count as origin-zero
790 and applying to the value being stored now. */
792 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
795 struct value_history_chunk
*new
796 = (struct value_history_chunk
*)
797 xmalloc (sizeof (struct value_history_chunk
));
798 memset (new->values
, 0, sizeof new->values
);
799 new->next
= value_history_chain
;
800 value_history_chain
= new;
803 value_history_chain
->values
[i
] = val
;
805 /* Now we regard value_history_count as origin-one
806 and applying to the value just stored. */
808 return ++value_history_count
;
811 /* Return a copy of the value in the history with sequence number NUM. */
814 access_value_history (int num
)
816 struct value_history_chunk
*chunk
;
821 absnum
+= value_history_count
;
826 error (_("The history is empty."));
828 error (_("There is only one value in the history."));
830 error (_("History does not go back to $$%d."), -num
);
832 if (absnum
> value_history_count
)
833 error (_("History has not yet reached $%d."), absnum
);
837 /* Now absnum is always absolute and origin zero. */
839 chunk
= value_history_chain
;
840 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
844 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
848 show_values (char *num_exp
, int from_tty
)
856 /* "show values +" should print from the stored position.
857 "show values <exp>" should print around value number <exp>. */
858 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
859 num
= parse_and_eval_long (num_exp
) - 5;
863 /* "show values" means print the last 10 values. */
864 num
= value_history_count
- 9;
870 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
872 struct value_print_options opts
;
873 val
= access_value_history (i
);
874 printf_filtered (("$%d = "), i
);
875 get_user_print_options (&opts
);
876 value_print (val
, gdb_stdout
, &opts
);
877 printf_filtered (("\n"));
880 /* The next "show values +" should start after what we just printed. */
883 /* Hitting just return after this command should do the same thing as
884 "show values +". If num_exp is null, this is unnecessary, since
885 "show values +" is not useful after "show values". */
886 if (from_tty
&& num_exp
)
893 /* Internal variables. These are variables within the debugger
894 that hold values assigned by debugger commands.
895 The user refers to them with a '$' prefix
896 that does not appear in the variable names stored internally. */
900 struct internalvar
*next
;
903 /* We support various different kinds of content of an internal variable.
904 enum internalvar_kind specifies the kind, and union internalvar_data
905 provides the data associated with this particular kind. */
907 enum internalvar_kind
909 /* The internal variable is empty. */
912 /* The value of the internal variable is provided directly as
913 a GDB value object. */
916 /* A fresh value is computed via a call-back routine on every
917 access to the internal variable. */
918 INTERNALVAR_MAKE_VALUE
,
920 /* The internal variable holds a GDB internal convenience function. */
921 INTERNALVAR_FUNCTION
,
923 /* The variable holds an integer value. */
926 /* The variable holds a pointer value. */
929 /* The variable holds a GDB-provided string. */
934 union internalvar_data
936 /* A value object used with INTERNALVAR_VALUE. */
939 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
940 internalvar_make_value make_value
;
942 /* The internal function used with INTERNALVAR_FUNCTION. */
945 struct internal_function
*function
;
946 /* True if this is the canonical name for the function. */
950 /* An integer value used with INTERNALVAR_INTEGER. */
953 /* If type is non-NULL, it will be used as the type to generate
954 a value for this internal variable. If type is NULL, a default
955 integer type for the architecture is used. */
960 /* A pointer value used with INTERNALVAR_POINTER. */
967 /* A string value used with INTERNALVAR_STRING. */
972 static struct internalvar
*internalvars
;
974 /* If the variable does not already exist create it and give it the value given.
975 If no value is given then the default is zero. */
977 init_if_undefined_command (char* args
, int from_tty
)
979 struct internalvar
* intvar
;
981 /* Parse the expression - this is taken from set_command(). */
982 struct expression
*expr
= parse_expression (args
);
983 register struct cleanup
*old_chain
=
984 make_cleanup (free_current_contents
, &expr
);
986 /* Validate the expression.
987 Was the expression an assignment?
988 Or even an expression at all? */
989 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
990 error (_("Init-if-undefined requires an assignment expression."));
992 /* Extract the variable from the parsed expression.
993 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
994 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
995 error (_("The first parameter to init-if-undefined should be a GDB variable."));
996 intvar
= expr
->elts
[2].internalvar
;
998 /* Only evaluate the expression if the lvalue is void.
999 This may still fail if the expresssion is invalid. */
1000 if (intvar
->kind
== INTERNALVAR_VOID
)
1001 evaluate_expression (expr
);
1003 do_cleanups (old_chain
);
1007 /* Look up an internal variable with name NAME. NAME should not
1008 normally include a dollar sign.
1010 If the specified internal variable does not exist,
1011 the return value is NULL. */
1013 struct internalvar
*
1014 lookup_only_internalvar (const char *name
)
1016 struct internalvar
*var
;
1018 for (var
= internalvars
; var
; var
= var
->next
)
1019 if (strcmp (var
->name
, name
) == 0)
1026 /* Create an internal variable with name NAME and with a void value.
1027 NAME should not normally include a dollar sign. */
1029 struct internalvar
*
1030 create_internalvar (const char *name
)
1032 struct internalvar
*var
;
1033 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
1034 var
->name
= concat (name
, (char *)NULL
);
1035 var
->kind
= INTERNALVAR_VOID
;
1036 var
->next
= internalvars
;
1041 /* Create an internal variable with name NAME and register FUN as the
1042 function that value_of_internalvar uses to create a value whenever
1043 this variable is referenced. NAME should not normally include a
1046 struct internalvar
*
1047 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
1049 struct internalvar
*var
= create_internalvar (name
);
1050 var
->kind
= INTERNALVAR_MAKE_VALUE
;
1051 var
->u
.make_value
= fun
;
1055 /* Look up an internal variable with name NAME. NAME should not
1056 normally include a dollar sign.
1058 If the specified internal variable does not exist,
1059 one is created, with a void value. */
1061 struct internalvar
*
1062 lookup_internalvar (const char *name
)
1064 struct internalvar
*var
;
1066 var
= lookup_only_internalvar (name
);
1070 return create_internalvar (name
);
1073 /* Return current value of internal variable VAR. For variables that
1074 are not inherently typed, use a value type appropriate for GDBARCH. */
1077 value_of_internalvar (struct gdbarch
*gdbarch
, struct internalvar
*var
)
1083 case INTERNALVAR_VOID
:
1084 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1087 case INTERNALVAR_FUNCTION
:
1088 val
= allocate_value (builtin_type (gdbarch
)->internal_fn
);
1091 case INTERNALVAR_INTEGER
:
1092 if (!var
->u
.integer
.type
)
1093 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
1094 var
->u
.integer
.val
);
1096 val
= value_from_longest (var
->u
.integer
.type
, var
->u
.integer
.val
);
1099 case INTERNALVAR_POINTER
:
1100 val
= value_from_pointer (var
->u
.pointer
.type
, var
->u
.pointer
.val
);
1103 case INTERNALVAR_STRING
:
1104 val
= value_cstring (var
->u
.string
, strlen (var
->u
.string
),
1105 builtin_type (gdbarch
)->builtin_char
);
1108 case INTERNALVAR_VALUE
:
1109 val
= value_copy (var
->u
.value
);
1110 if (value_lazy (val
))
1111 value_fetch_lazy (val
);
1114 case INTERNALVAR_MAKE_VALUE
:
1115 val
= (*var
->u
.make_value
) (gdbarch
, var
);
1119 internal_error (__FILE__
, __LINE__
, "bad kind");
1122 /* Change the VALUE_LVAL to lval_internalvar so that future operations
1123 on this value go back to affect the original internal variable.
1125 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
1126 no underlying modifyable state in the internal variable.
1128 Likewise, if the variable's value is a computed lvalue, we want
1129 references to it to produce another computed lvalue, where
1130 references and assignments actually operate through the
1131 computed value's functions.
1133 This means that internal variables with computed values
1134 behave a little differently from other internal variables:
1135 assignments to them don't just replace the previous value
1136 altogether. At the moment, this seems like the behavior we
1139 if (var
->kind
!= INTERNALVAR_MAKE_VALUE
1140 && val
->lval
!= lval_computed
)
1142 VALUE_LVAL (val
) = lval_internalvar
;
1143 VALUE_INTERNALVAR (val
) = var
;
1150 get_internalvar_integer (struct internalvar
*var
, LONGEST
*result
)
1154 case INTERNALVAR_INTEGER
:
1155 *result
= var
->u
.integer
.val
;
1164 get_internalvar_function (struct internalvar
*var
,
1165 struct internal_function
**result
)
1169 case INTERNALVAR_FUNCTION
:
1170 *result
= var
->u
.fn
.function
;
1179 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1180 int bitsize
, struct value
*newval
)
1186 case INTERNALVAR_VALUE
:
1187 addr
= value_contents_writeable (var
->u
.value
);
1190 modify_field (value_type (var
->u
.value
), addr
+ offset
,
1191 value_as_long (newval
), bitpos
, bitsize
);
1193 memcpy (addr
+ offset
, value_contents (newval
),
1194 TYPE_LENGTH (value_type (newval
)));
1198 /* We can never get a component of any other kind. */
1199 internal_error (__FILE__
, __LINE__
, "set_internalvar_component");
1204 set_internalvar (struct internalvar
*var
, struct value
*val
)
1206 enum internalvar_kind new_kind
;
1207 union internalvar_data new_data
= { 0 };
1209 if (var
->kind
== INTERNALVAR_FUNCTION
&& var
->u
.fn
.canonical
)
1210 error (_("Cannot overwrite convenience function %s"), var
->name
);
1212 /* Prepare new contents. */
1213 switch (TYPE_CODE (check_typedef (value_type (val
))))
1215 case TYPE_CODE_VOID
:
1216 new_kind
= INTERNALVAR_VOID
;
1219 case TYPE_CODE_INTERNAL_FUNCTION
:
1220 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1221 new_kind
= INTERNALVAR_FUNCTION
;
1222 get_internalvar_function (VALUE_INTERNALVAR (val
),
1223 &new_data
.fn
.function
);
1224 /* Copies created here are never canonical. */
1228 new_kind
= INTERNALVAR_INTEGER
;
1229 new_data
.integer
.type
= value_type (val
);
1230 new_data
.integer
.val
= value_as_long (val
);
1234 new_kind
= INTERNALVAR_POINTER
;
1235 new_data
.pointer
.type
= value_type (val
);
1236 new_data
.pointer
.val
= value_as_address (val
);
1240 new_kind
= INTERNALVAR_VALUE
;
1241 new_data
.value
= value_copy (val
);
1242 new_data
.value
->modifiable
= 1;
1244 /* Force the value to be fetched from the target now, to avoid problems
1245 later when this internalvar is referenced and the target is gone or
1247 if (value_lazy (new_data
.value
))
1248 value_fetch_lazy (new_data
.value
);
1250 /* Release the value from the value chain to prevent it from being
1251 deleted by free_all_values. From here on this function should not
1252 call error () until new_data is installed into the var->u to avoid
1254 release_value (new_data
.value
);
1258 /* Clean up old contents. */
1259 clear_internalvar (var
);
1262 var
->kind
= new_kind
;
1264 /* End code which must not call error(). */
1268 set_internalvar_integer (struct internalvar
*var
, LONGEST l
)
1270 /* Clean up old contents. */
1271 clear_internalvar (var
);
1273 var
->kind
= INTERNALVAR_INTEGER
;
1274 var
->u
.integer
.type
= NULL
;
1275 var
->u
.integer
.val
= l
;
1279 set_internalvar_string (struct internalvar
*var
, const char *string
)
1281 /* Clean up old contents. */
1282 clear_internalvar (var
);
1284 var
->kind
= INTERNALVAR_STRING
;
1285 var
->u
.string
= xstrdup (string
);
1289 set_internalvar_function (struct internalvar
*var
, struct internal_function
*f
)
1291 /* Clean up old contents. */
1292 clear_internalvar (var
);
1294 var
->kind
= INTERNALVAR_FUNCTION
;
1295 var
->u
.fn
.function
= f
;
1296 var
->u
.fn
.canonical
= 1;
1297 /* Variables installed here are always the canonical version. */
1301 clear_internalvar (struct internalvar
*var
)
1303 /* Clean up old contents. */
1306 case INTERNALVAR_VALUE
:
1307 value_free (var
->u
.value
);
1310 case INTERNALVAR_STRING
:
1311 xfree (var
->u
.string
);
1318 /* Reset to void kind. */
1319 var
->kind
= INTERNALVAR_VOID
;
1323 internalvar_name (struct internalvar
*var
)
1328 static struct internal_function
*
1329 create_internal_function (const char *name
,
1330 internal_function_fn handler
, void *cookie
)
1332 struct internal_function
*ifn
= XNEW (struct internal_function
);
1333 ifn
->name
= xstrdup (name
);
1334 ifn
->handler
= handler
;
1335 ifn
->cookie
= cookie
;
1340 value_internal_function_name (struct value
*val
)
1342 struct internal_function
*ifn
;
1345 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1346 result
= get_internalvar_function (VALUE_INTERNALVAR (val
), &ifn
);
1347 gdb_assert (result
);
1353 call_internal_function (struct gdbarch
*gdbarch
,
1354 const struct language_defn
*language
,
1355 struct value
*func
, int argc
, struct value
**argv
)
1357 struct internal_function
*ifn
;
1360 gdb_assert (VALUE_LVAL (func
) == lval_internalvar
);
1361 result
= get_internalvar_function (VALUE_INTERNALVAR (func
), &ifn
);
1362 gdb_assert (result
);
1364 return (*ifn
->handler
) (gdbarch
, language
, ifn
->cookie
, argc
, argv
);
1367 /* The 'function' command. This does nothing -- it is just a
1368 placeholder to let "help function NAME" work. This is also used as
1369 the implementation of the sub-command that is created when
1370 registering an internal function. */
1372 function_command (char *command
, int from_tty
)
1377 /* Clean up if an internal function's command is destroyed. */
1379 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1385 /* Add a new internal function. NAME is the name of the function; DOC
1386 is a documentation string describing the function. HANDLER is
1387 called when the function is invoked. COOKIE is an arbitrary
1388 pointer which is passed to HANDLER and is intended for "user
1391 add_internal_function (const char *name
, const char *doc
,
1392 internal_function_fn handler
, void *cookie
)
1394 struct cmd_list_element
*cmd
;
1395 struct internal_function
*ifn
;
1396 struct internalvar
*var
= lookup_internalvar (name
);
1398 ifn
= create_internal_function (name
, handler
, cookie
);
1399 set_internalvar_function (var
, ifn
);
1401 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1403 cmd
->destroyer
= function_destroyer
;
1406 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1407 prevent cycles / duplicates. */
1410 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1411 htab_t copied_types
)
1413 if (TYPE_OBJFILE (value
->type
) == objfile
)
1414 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1416 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1417 value
->enclosing_type
= copy_type_recursive (objfile
,
1418 value
->enclosing_type
,
1422 /* Likewise for internal variable VAR. */
1425 preserve_one_internalvar (struct internalvar
*var
, struct objfile
*objfile
,
1426 htab_t copied_types
)
1430 case INTERNALVAR_INTEGER
:
1431 if (var
->u
.integer
.type
&& TYPE_OBJFILE (var
->u
.integer
.type
) == objfile
)
1433 = copy_type_recursive (objfile
, var
->u
.integer
.type
, copied_types
);
1436 case INTERNALVAR_POINTER
:
1437 if (TYPE_OBJFILE (var
->u
.pointer
.type
) == objfile
)
1439 = copy_type_recursive (objfile
, var
->u
.pointer
.type
, copied_types
);
1442 case INTERNALVAR_VALUE
:
1443 preserve_one_value (var
->u
.value
, objfile
, copied_types
);
1448 /* Update the internal variables and value history when OBJFILE is
1449 discarded; we must copy the types out of the objfile. New global types
1450 will be created for every convenience variable which currently points to
1451 this objfile's types, and the convenience variables will be adjusted to
1452 use the new global types. */
1455 preserve_values (struct objfile
*objfile
)
1457 htab_t copied_types
;
1458 struct value_history_chunk
*cur
;
1459 struct internalvar
*var
;
1463 /* Create the hash table. We allocate on the objfile's obstack, since
1464 it is soon to be deleted. */
1465 copied_types
= create_copied_types_hash (objfile
);
1467 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1468 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1470 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1472 for (var
= internalvars
; var
; var
= var
->next
)
1473 preserve_one_internalvar (var
, objfile
, copied_types
);
1475 preserve_python_values (objfile
, copied_types
);
1477 htab_delete (copied_types
);
1481 show_convenience (char *ignore
, int from_tty
)
1483 struct gdbarch
*gdbarch
= get_current_arch ();
1484 struct internalvar
*var
;
1486 struct value_print_options opts
;
1488 get_user_print_options (&opts
);
1489 for (var
= internalvars
; var
; var
= var
->next
)
1495 printf_filtered (("$%s = "), var
->name
);
1496 value_print (value_of_internalvar (gdbarch
, var
), gdb_stdout
,
1498 printf_filtered (("\n"));
1501 printf_unfiltered (_("\
1502 No debugger convenience variables now defined.\n\
1503 Convenience variables have names starting with \"$\";\n\
1504 use \"set\" as in \"set $foo = 5\" to define them.\n"));
1507 /* Extract a value as a C number (either long or double).
1508 Knows how to convert fixed values to double, or
1509 floating values to long.
1510 Does not deallocate the value. */
1513 value_as_long (struct value
*val
)
1515 /* This coerces arrays and functions, which is necessary (e.g.
1516 in disassemble_command). It also dereferences references, which
1517 I suspect is the most logical thing to do. */
1518 val
= coerce_array (val
);
1519 return unpack_long (value_type (val
), value_contents (val
));
1523 value_as_double (struct value
*val
)
1528 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1530 error (_("Invalid floating value found in program."));
1534 /* Extract a value as a C pointer. Does not deallocate the value.
1535 Note that val's type may not actually be a pointer; value_as_long
1536 handles all the cases. */
1538 value_as_address (struct value
*val
)
1540 struct gdbarch
*gdbarch
= get_type_arch (value_type (val
));
1542 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1543 whether we want this to be true eventually. */
1545 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1546 non-address (e.g. argument to "signal", "info break", etc.), or
1547 for pointers to char, in which the low bits *are* significant. */
1548 return gdbarch_addr_bits_remove (gdbarch
, value_as_long (val
));
1551 /* There are several targets (IA-64, PowerPC, and others) which
1552 don't represent pointers to functions as simply the address of
1553 the function's entry point. For example, on the IA-64, a
1554 function pointer points to a two-word descriptor, generated by
1555 the linker, which contains the function's entry point, and the
1556 value the IA-64 "global pointer" register should have --- to
1557 support position-independent code. The linker generates
1558 descriptors only for those functions whose addresses are taken.
1560 On such targets, it's difficult for GDB to convert an arbitrary
1561 function address into a function pointer; it has to either find
1562 an existing descriptor for that function, or call malloc and
1563 build its own. On some targets, it is impossible for GDB to
1564 build a descriptor at all: the descriptor must contain a jump
1565 instruction; data memory cannot be executed; and code memory
1568 Upon entry to this function, if VAL is a value of type `function'
1569 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1570 value_address (val) is the address of the function. This is what
1571 you'll get if you evaluate an expression like `main'. The call
1572 to COERCE_ARRAY below actually does all the usual unary
1573 conversions, which includes converting values of type `function'
1574 to `pointer to function'. This is the challenging conversion
1575 discussed above. Then, `unpack_long' will convert that pointer
1576 back into an address.
1578 So, suppose the user types `disassemble foo' on an architecture
1579 with a strange function pointer representation, on which GDB
1580 cannot build its own descriptors, and suppose further that `foo'
1581 has no linker-built descriptor. The address->pointer conversion
1582 will signal an error and prevent the command from running, even
1583 though the next step would have been to convert the pointer
1584 directly back into the same address.
1586 The following shortcut avoids this whole mess. If VAL is a
1587 function, just return its address directly. */
1588 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
1589 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
1590 return value_address (val
);
1592 val
= coerce_array (val
);
1594 /* Some architectures (e.g. Harvard), map instruction and data
1595 addresses onto a single large unified address space. For
1596 instance: An architecture may consider a large integer in the
1597 range 0x10000000 .. 0x1000ffff to already represent a data
1598 addresses (hence not need a pointer to address conversion) while
1599 a small integer would still need to be converted integer to
1600 pointer to address. Just assume such architectures handle all
1601 integer conversions in a single function. */
1605 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1606 must admonish GDB hackers to make sure its behavior matches the
1607 compiler's, whenever possible.
1609 In general, I think GDB should evaluate expressions the same way
1610 the compiler does. When the user copies an expression out of
1611 their source code and hands it to a `print' command, they should
1612 get the same value the compiler would have computed. Any
1613 deviation from this rule can cause major confusion and annoyance,
1614 and needs to be justified carefully. In other words, GDB doesn't
1615 really have the freedom to do these conversions in clever and
1618 AndrewC pointed out that users aren't complaining about how GDB
1619 casts integers to pointers; they are complaining that they can't
1620 take an address from a disassembly listing and give it to `x/i'.
1621 This is certainly important.
1623 Adding an architecture method like integer_to_address() certainly
1624 makes it possible for GDB to "get it right" in all circumstances
1625 --- the target has complete control over how things get done, so
1626 people can Do The Right Thing for their target without breaking
1627 anyone else. The standard doesn't specify how integers get
1628 converted to pointers; usually, the ABI doesn't either, but
1629 ABI-specific code is a more reasonable place to handle it. */
1631 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
1632 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
1633 && gdbarch_integer_to_address_p (gdbarch
))
1634 return gdbarch_integer_to_address (gdbarch
, value_type (val
),
1635 value_contents (val
));
1637 return unpack_long (value_type (val
), value_contents (val
));
1641 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1642 as a long, or as a double, assuming the raw data is described
1643 by type TYPE. Knows how to convert different sizes of values
1644 and can convert between fixed and floating point. We don't assume
1645 any alignment for the raw data. Return value is in host byte order.
1647 If you want functions and arrays to be coerced to pointers, and
1648 references to be dereferenced, call value_as_long() instead.
1650 C++: It is assumed that the front-end has taken care of
1651 all matters concerning pointers to members. A pointer
1652 to member which reaches here is considered to be equivalent
1653 to an INT (or some size). After all, it is only an offset. */
1656 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
1658 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1659 enum type_code code
= TYPE_CODE (type
);
1660 int len
= TYPE_LENGTH (type
);
1661 int nosign
= TYPE_UNSIGNED (type
);
1665 case TYPE_CODE_TYPEDEF
:
1666 return unpack_long (check_typedef (type
), valaddr
);
1667 case TYPE_CODE_ENUM
:
1668 case TYPE_CODE_FLAGS
:
1669 case TYPE_CODE_BOOL
:
1671 case TYPE_CODE_CHAR
:
1672 case TYPE_CODE_RANGE
:
1673 case TYPE_CODE_MEMBERPTR
:
1675 return extract_unsigned_integer (valaddr
, len
, byte_order
);
1677 return extract_signed_integer (valaddr
, len
, byte_order
);
1680 return extract_typed_floating (valaddr
, type
);
1682 case TYPE_CODE_DECFLOAT
:
1683 /* libdecnumber has a function to convert from decimal to integer, but
1684 it doesn't work when the decimal number has a fractional part. */
1685 return decimal_to_doublest (valaddr
, len
, byte_order
);
1689 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1690 whether we want this to be true eventually. */
1691 return extract_typed_address (valaddr
, type
);
1694 error (_("Value can't be converted to integer."));
1696 return 0; /* Placate lint. */
1699 /* Return a double value from the specified type and address.
1700 INVP points to an int which is set to 0 for valid value,
1701 1 for invalid value (bad float format). In either case,
1702 the returned double is OK to use. Argument is in target
1703 format, result is in host format. */
1706 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
1708 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1709 enum type_code code
;
1713 *invp
= 0; /* Assume valid. */
1714 CHECK_TYPEDEF (type
);
1715 code
= TYPE_CODE (type
);
1716 len
= TYPE_LENGTH (type
);
1717 nosign
= TYPE_UNSIGNED (type
);
1718 if (code
== TYPE_CODE_FLT
)
1720 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1721 floating-point value was valid (using the macro
1722 INVALID_FLOAT). That test/macro have been removed.
1724 It turns out that only the VAX defined this macro and then
1725 only in a non-portable way. Fixing the portability problem
1726 wouldn't help since the VAX floating-point code is also badly
1727 bit-rotten. The target needs to add definitions for the
1728 methods gdbarch_float_format and gdbarch_double_format - these
1729 exactly describe the target floating-point format. The
1730 problem here is that the corresponding floatformat_vax_f and
1731 floatformat_vax_d values these methods should be set to are
1732 also not defined either. Oops!
1734 Hopefully someone will add both the missing floatformat
1735 definitions and the new cases for floatformat_is_valid (). */
1737 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
1743 return extract_typed_floating (valaddr
, type
);
1745 else if (code
== TYPE_CODE_DECFLOAT
)
1746 return decimal_to_doublest (valaddr
, len
, byte_order
);
1749 /* Unsigned -- be sure we compensate for signed LONGEST. */
1750 return (ULONGEST
) unpack_long (type
, valaddr
);
1754 /* Signed -- we are OK with unpack_long. */
1755 return unpack_long (type
, valaddr
);
1759 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1760 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1761 We don't assume any alignment for the raw data. Return value is in
1764 If you want functions and arrays to be coerced to pointers, and
1765 references to be dereferenced, call value_as_address() instead.
1767 C++: It is assumed that the front-end has taken care of
1768 all matters concerning pointers to members. A pointer
1769 to member which reaches here is considered to be equivalent
1770 to an INT (or some size). After all, it is only an offset. */
1773 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
1775 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1776 whether we want this to be true eventually. */
1777 return unpack_long (type
, valaddr
);
1781 /* Get the value of the FIELDN'th field (which must be static) of
1782 TYPE. Return NULL if the field doesn't exist or has been
1786 value_static_field (struct type
*type
, int fieldno
)
1788 struct value
*retval
;
1790 if (TYPE_FIELD_LOC_KIND (type
, fieldno
) == FIELD_LOC_KIND_PHYSADDR
)
1792 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1793 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1797 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1798 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1801 /* With some compilers, e.g. HP aCC, static data members are reported
1802 as non-debuggable symbols */
1803 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
, NULL
, NULL
);
1808 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1809 SYMBOL_VALUE_ADDRESS (msym
));
1814 /* SYM should never have a SYMBOL_CLASS which will require
1815 read_var_value to use the FRAME parameter. */
1816 if (symbol_read_needs_frame (sym
))
1817 warning (_("static field's value depends on the current "
1818 "frame - bad debug info?"));
1819 retval
= read_var_value (sym
, NULL
);
1821 if (retval
&& VALUE_LVAL (retval
) == lval_memory
)
1822 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
),
1823 value_address (retval
));
1828 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1829 You have to be careful here, since the size of the data area for the value
1830 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1831 than the old enclosing type, you have to allocate more space for the data.
1832 The return value is a pointer to the new version of this value structure. */
1835 value_change_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
1837 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
1839 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
1841 val
->enclosing_type
= new_encl_type
;
1845 /* Given a value ARG1 (offset by OFFSET bytes)
1846 of a struct or union type ARG_TYPE,
1847 extract and return the value of one of its (non-static) fields.
1848 FIELDNO says which field. */
1851 value_primitive_field (struct value
*arg1
, int offset
,
1852 int fieldno
, struct type
*arg_type
)
1857 CHECK_TYPEDEF (arg_type
);
1858 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
1860 /* Handle packed fields */
1862 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
1864 /* Create a new value for the bitfield, with bitpos and bitsize
1865 set. If possible, arrange offset and bitpos so that we can
1866 do a single aligned read of the size of the containing type.
1867 Otherwise, adjust offset to the byte containing the first
1868 bit. Assume that the address, offset, and embedded offset
1869 are sufficiently aligned. */
1870 int bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
);
1871 int container_bitsize
= TYPE_LENGTH (type
) * 8;
1873 v
= allocate_value_lazy (type
);
1874 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
1875 if ((bitpos
% container_bitsize
) + v
->bitsize
<= container_bitsize
1876 && TYPE_LENGTH (type
) <= (int) sizeof (LONGEST
))
1877 v
->bitpos
= bitpos
% container_bitsize
;
1879 v
->bitpos
= bitpos
% 8;
1880 v
->offset
= value_offset (arg1
) + value_embedded_offset (arg1
)
1881 + (bitpos
- v
->bitpos
) / 8;
1883 value_incref (v
->parent
);
1884 if (!value_lazy (arg1
))
1885 value_fetch_lazy (v
);
1887 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
1889 /* This field is actually a base subobject, so preserve the
1890 entire object's contents for later references to virtual
1893 /* Lazy register values with offsets are not supported. */
1894 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1895 value_fetch_lazy (arg1
);
1897 if (value_lazy (arg1
))
1898 v
= allocate_value_lazy (value_enclosing_type (arg1
));
1901 v
= allocate_value (value_enclosing_type (arg1
));
1902 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
1903 TYPE_LENGTH (value_enclosing_type (arg1
)));
1906 v
->offset
= value_offset (arg1
);
1907 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
1908 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
1912 /* Plain old data member */
1913 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1915 /* Lazy register values with offsets are not supported. */
1916 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1917 value_fetch_lazy (arg1
);
1919 if (value_lazy (arg1
))
1920 v
= allocate_value_lazy (type
);
1923 v
= allocate_value (type
);
1924 memcpy (value_contents_raw (v
),
1925 value_contents_raw (arg1
) + offset
,
1926 TYPE_LENGTH (type
));
1928 v
->offset
= (value_offset (arg1
) + offset
1929 + value_embedded_offset (arg1
));
1931 set_value_component_location (v
, arg1
);
1932 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
1933 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
1937 /* Given a value ARG1 of a struct or union type,
1938 extract and return the value of one of its (non-static) fields.
1939 FIELDNO says which field. */
1942 value_field (struct value
*arg1
, int fieldno
)
1944 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
1947 /* Return a non-virtual function as a value.
1948 F is the list of member functions which contains the desired method.
1949 J is an index into F which provides the desired method.
1951 We only use the symbol for its address, so be happy with either a
1952 full symbol or a minimal symbol.
1956 value_fn_field (struct value
**arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
1960 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
1961 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
1963 struct minimal_symbol
*msym
;
1965 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
1972 gdb_assert (sym
== NULL
);
1973 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
1978 v
= allocate_value (ftype
);
1981 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
1985 /* The minimal symbol might point to a function descriptor;
1986 resolve it to the actual code address instead. */
1987 struct objfile
*objfile
= msymbol_objfile (msym
);
1988 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
1990 set_value_address (v
,
1991 gdbarch_convert_from_func_ptr_addr
1992 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
1997 if (type
!= value_type (*arg1p
))
1998 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
1999 value_addr (*arg1p
)));
2001 /* Move the `this' pointer according to the offset.
2002 VALUE_OFFSET (*arg1p) += offset;
2010 /* Unpack a bitfield of the specified FIELD_TYPE, from the anonymous
2011 object at VALADDR. The bitfield starts at BITPOS bits and contains
2014 Extracting bits depends on endianness of the machine. Compute the
2015 number of least significant bits to discard. For big endian machines,
2016 we compute the total number of bits in the anonymous object, subtract
2017 off the bit count from the MSB of the object to the MSB of the
2018 bitfield, then the size of the bitfield, which leaves the LSB discard
2019 count. For little endian machines, the discard count is simply the
2020 number of bits from the LSB of the anonymous object to the LSB of the
2023 If the field is signed, we also do sign extension. */
2026 unpack_bits_as_long (struct type
*field_type
, const gdb_byte
*valaddr
,
2027 int bitpos
, int bitsize
)
2029 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (field_type
));
2034 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8,
2035 sizeof (val
), byte_order
);
2036 CHECK_TYPEDEF (field_type
);
2038 /* Extract bits. See comment above. */
2040 if (gdbarch_bits_big_endian (get_type_arch (field_type
)))
2041 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
2043 lsbcount
= (bitpos
% 8);
2046 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
2047 If the field is signed, and is negative, then sign extend. */
2049 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
2051 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
2053 if (!TYPE_UNSIGNED (field_type
))
2055 if (val
& (valmask
^ (valmask
>> 1)))
2064 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
2065 VALADDR. See unpack_bits_as_long for more details. */
2068 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
2070 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
2071 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
2072 struct type
*field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
2074 return unpack_bits_as_long (field_type
, valaddr
, bitpos
, bitsize
);
2077 /* Modify the value of a bitfield. ADDR points to a block of memory in
2078 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
2079 is the desired value of the field, in host byte order. BITPOS and BITSIZE
2080 indicate which bits (in target bit order) comprise the bitfield.
2081 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS+BITSIZE <= lbits, and
2082 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
2085 modify_field (struct type
*type
, gdb_byte
*addr
,
2086 LONGEST fieldval
, int bitpos
, int bitsize
)
2088 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2090 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
2092 /* If a negative fieldval fits in the field in question, chop
2093 off the sign extension bits. */
2094 if ((~fieldval
& ~(mask
>> 1)) == 0)
2097 /* Warn if value is too big to fit in the field in question. */
2098 if (0 != (fieldval
& ~mask
))
2100 /* FIXME: would like to include fieldval in the message, but
2101 we don't have a sprintf_longest. */
2102 warning (_("Value does not fit in %d bits."), bitsize
);
2104 /* Truncate it, otherwise adjoining fields may be corrupted. */
2108 oword
= extract_unsigned_integer (addr
, sizeof oword
, byte_order
);
2110 /* Shifting for bit field depends on endianness of the target machine. */
2111 if (gdbarch_bits_big_endian (get_type_arch (type
)))
2112 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
2114 oword
&= ~(mask
<< bitpos
);
2115 oword
|= fieldval
<< bitpos
;
2117 store_unsigned_integer (addr
, sizeof oword
, byte_order
, oword
);
2120 /* Pack NUM into BUF using a target format of TYPE. */
2123 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
2125 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2128 type
= check_typedef (type
);
2129 len
= TYPE_LENGTH (type
);
2131 switch (TYPE_CODE (type
))
2134 case TYPE_CODE_CHAR
:
2135 case TYPE_CODE_ENUM
:
2136 case TYPE_CODE_FLAGS
:
2137 case TYPE_CODE_BOOL
:
2138 case TYPE_CODE_RANGE
:
2139 case TYPE_CODE_MEMBERPTR
:
2140 store_signed_integer (buf
, len
, byte_order
, num
);
2145 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2149 error (_("Unexpected type (%d) encountered for integer constant."),
2155 /* Convert C numbers into newly allocated values. */
2158 value_from_longest (struct type
*type
, LONGEST num
)
2160 struct value
*val
= allocate_value (type
);
2162 pack_long (value_contents_raw (val
), type
, num
);
2168 /* Create a value representing a pointer of type TYPE to the address
2171 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
2173 struct value
*val
= allocate_value (type
);
2174 store_typed_address (value_contents_raw (val
), check_typedef (type
), addr
);
2179 /* Create a value of type TYPE whose contents come from VALADDR, if it
2180 is non-null, and whose memory address (in the inferior) is
2184 value_from_contents_and_address (struct type
*type
,
2185 const gdb_byte
*valaddr
,
2188 struct value
*v
= allocate_value (type
);
2189 if (valaddr
== NULL
)
2190 set_value_lazy (v
, 1);
2192 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
2193 set_value_address (v
, address
);
2194 VALUE_LVAL (v
) = lval_memory
;
2199 value_from_double (struct type
*type
, DOUBLEST num
)
2201 struct value
*val
= allocate_value (type
);
2202 struct type
*base_type
= check_typedef (type
);
2203 enum type_code code
= TYPE_CODE (base_type
);
2204 int len
= TYPE_LENGTH (base_type
);
2206 if (code
== TYPE_CODE_FLT
)
2208 store_typed_floating (value_contents_raw (val
), base_type
, num
);
2211 error (_("Unexpected type encountered for floating constant."));
2217 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
2219 struct value
*val
= allocate_value (type
);
2221 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
2227 coerce_ref (struct value
*arg
)
2229 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
2230 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
2231 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
2232 unpack_pointer (value_type (arg
),
2233 value_contents (arg
)));
2238 coerce_array (struct value
*arg
)
2242 arg
= coerce_ref (arg
);
2243 type
= check_typedef (value_type (arg
));
2245 switch (TYPE_CODE (type
))
2247 case TYPE_CODE_ARRAY
:
2248 if (current_language
->c_style_arrays
)
2249 arg
= value_coerce_array (arg
);
2251 case TYPE_CODE_FUNC
:
2252 arg
= value_coerce_function (arg
);
2259 /* Return true if the function returning the specified type is using
2260 the convention of returning structures in memory (passing in the
2261 address as a hidden first parameter). */
2264 using_struct_return (struct gdbarch
*gdbarch
,
2265 struct type
*func_type
, struct type
*value_type
)
2267 enum type_code code
= TYPE_CODE (value_type
);
2269 if (code
== TYPE_CODE_ERROR
)
2270 error (_("Function return type unknown."));
2272 if (code
== TYPE_CODE_VOID
)
2273 /* A void return value is never in memory. See also corresponding
2274 code in "print_return_value". */
2277 /* Probe the architecture for the return-value convention. */
2278 return (gdbarch_return_value (gdbarch
, func_type
, value_type
,
2280 != RETURN_VALUE_REGISTER_CONVENTION
);
2283 /* Set the initialized field in a value struct. */
2286 set_value_initialized (struct value
*val
, int status
)
2288 val
->initialized
= status
;
2291 /* Return the initialized field in a value struct. */
2294 value_initialized (struct value
*val
)
2296 return val
->initialized
;
2300 _initialize_values (void)
2302 add_cmd ("convenience", no_class
, show_convenience
, _("\
2303 Debugger convenience (\"$foo\") variables.\n\
2304 These variables are created when you assign them values;\n\
2305 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2307 A few convenience variables are given values automatically:\n\
2308 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2309 \"$__\" holds the contents of the last address examined with \"x\"."),
2312 add_cmd ("values", no_class
, show_values
,
2313 _("Elements of value history around item number IDX (or last ten)."),
2316 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2317 Initialize a convenience variable if necessary.\n\
2318 init-if-undefined VARIABLE = EXPRESSION\n\
2319 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2320 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2321 VARIABLE is already initialized."));
2323 add_prefix_cmd ("function", no_class
, function_command
, _("\
2324 Placeholder command for showing help on convenience functions."),
2325 &functionlist
, "function ", 0, &cmdlist
);