1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
3 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
4 1996, 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
5 2009, 2010 Free Software Foundation, Inc.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "arch-utils.h"
24 #include "gdb_string.h"
35 #include "gdb_assert.h"
41 #include "cli/cli-decode.h"
43 #include "python/python.h"
45 /* Prototypes for exported functions. */
47 void _initialize_values (void);
49 /* Definition of a user function. */
50 struct internal_function
52 /* The name of the function. It is a bit odd to have this in the
53 function itself -- the user might use a differently-named
54 convenience variable to hold the function. */
58 internal_function_fn handler
;
60 /* User data for the handler. */
64 static struct cmd_list_element
*functionlist
;
68 /* Type of value; either not an lval, or one of the various
69 different possible kinds of lval. */
72 /* Is it modifiable? Only relevant if lval != not_lval. */
75 /* Location of value (if lval). */
78 /* If lval == lval_memory, this is the address in the inferior.
79 If lval == lval_register, this is the byte offset into the
80 registers structure. */
83 /* Pointer to internal variable. */
84 struct internalvar
*internalvar
;
86 /* If lval == lval_computed, this is a set of function pointers
87 to use to access and describe the value, and a closure pointer
91 struct lval_funcs
*funcs
; /* Functions to call. */
92 void *closure
; /* Closure for those functions to use. */
96 /* Describes offset of a value within lval of a structure in bytes.
97 If lval == lval_memory, this is an offset to the address. If
98 lval == lval_register, this is a further offset from
99 location.address within the registers structure. Note also the
100 member embedded_offset below. */
103 /* Only used for bitfields; number of bits contained in them. */
106 /* Only used for bitfields; position of start of field. For
107 gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
108 gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
111 /* Only used for bitfields; the containing value. This allows a
112 single read from the target when displaying multiple
114 struct value
*parent
;
116 /* Frame register value is relative to. This will be described in
117 the lval enum above as "lval_register". */
118 struct frame_id frame_id
;
120 /* Type of the value. */
123 /* If a value represents a C++ object, then the `type' field gives
124 the object's compile-time type. If the object actually belongs
125 to some class derived from `type', perhaps with other base
126 classes and additional members, then `type' is just a subobject
127 of the real thing, and the full object is probably larger than
128 `type' would suggest.
130 If `type' is a dynamic class (i.e. one with a vtable), then GDB
131 can actually determine the object's run-time type by looking at
132 the run-time type information in the vtable. When this
133 information is available, we may elect to read in the entire
134 object, for several reasons:
136 - When printing the value, the user would probably rather see the
137 full object, not just the limited portion apparent from the
140 - If `type' has virtual base classes, then even printing `type'
141 alone may require reaching outside the `type' portion of the
142 object to wherever the virtual base class has been stored.
144 When we store the entire object, `enclosing_type' is the run-time
145 type -- the complete object -- and `embedded_offset' is the
146 offset of `type' within that larger type, in bytes. The
147 value_contents() macro takes `embedded_offset' into account, so
148 most GDB code continues to see the `type' portion of the value,
149 just as the inferior would.
151 If `type' is a pointer to an object, then `enclosing_type' is a
152 pointer to the object's run-time type, and `pointed_to_offset' is
153 the offset in bytes from the full object to the pointed-to object
154 -- that is, the value `embedded_offset' would have if we followed
155 the pointer and fetched the complete object. (I don't really see
156 the point. Why not just determine the run-time type when you
157 indirect, and avoid the special case? The contents don't matter
158 until you indirect anyway.)
160 If we're not doing anything fancy, `enclosing_type' is equal to
161 `type', and `embedded_offset' is zero, so everything works
163 struct type
*enclosing_type
;
165 int pointed_to_offset
;
167 /* Values are stored in a chain, so that they can be deleted easily
168 over calls to the inferior. Values assigned to internal
169 variables, put into the value history or exposed to Python are
170 taken off this list. */
173 /* Register number if the value is from a register. */
176 /* If zero, contents of this value are in the contents field. If
177 nonzero, contents are in inferior. If the lval field is lval_memory,
178 the contents are in inferior memory at location.address plus offset.
179 The lval field may also be lval_register.
181 WARNING: This field is used by the code which handles watchpoints
182 (see breakpoint.c) to decide whether a particular value can be
183 watched by hardware watchpoints. If the lazy flag is set for
184 some member of a value chain, it is assumed that this member of
185 the chain doesn't need to be watched as part of watching the
186 value itself. This is how GDB avoids watching the entire struct
187 or array when the user wants to watch a single struct member or
188 array element. If you ever change the way lazy flag is set and
189 reset, be sure to consider this use as well! */
192 /* If nonzero, this is the value of a variable which does not
193 actually exist in the program. */
196 /* If value is a variable, is it initialized or not. */
199 /* If value is from the stack. If this is set, read_stack will be
200 used instead of read_memory to enable extra caching. */
203 /* Actual contents of the value. Target byte-order. NULL or not
204 valid if lazy is nonzero. */
207 /* The number of references to this value. When a value is created,
208 the value chain holds a reference, so REFERENCE_COUNT is 1. If
209 release_value is called, this value is removed from the chain but
210 the caller of release_value now has a reference to this value.
211 The caller must arrange for a call to value_free later. */
215 /* Prototypes for local functions. */
217 static void show_values (char *, int);
219 static void show_convenience (char *, int);
222 /* The value-history records all the values printed
223 by print commands during this session. Each chunk
224 records 60 consecutive values. The first chunk on
225 the chain records the most recent values.
226 The total number of values is in value_history_count. */
228 #define VALUE_HISTORY_CHUNK 60
230 struct value_history_chunk
232 struct value_history_chunk
*next
;
233 struct value
*values
[VALUE_HISTORY_CHUNK
];
236 /* Chain of chunks now in use. */
238 static struct value_history_chunk
*value_history_chain
;
240 static int value_history_count
; /* Abs number of last entry stored */
243 /* List of all value objects currently allocated
244 (except for those released by calls to release_value)
245 This is so they can be freed after each command. */
247 static struct value
*all_values
;
249 /* Allocate a lazy value for type TYPE. Its actual content is
250 "lazily" allocated too: the content field of the return value is
251 NULL; it will be allocated when it is fetched from the target. */
254 allocate_value_lazy (struct type
*type
)
258 /* Call check_typedef on our type to make sure that, if TYPE
259 is a TYPE_CODE_TYPEDEF, its length is set to the length
260 of the target type instead of zero. However, we do not
261 replace the typedef type by the target type, because we want
262 to keep the typedef in order to be able to set the VAL's type
263 description correctly. */
264 check_typedef (type
);
266 val
= (struct value
*) xzalloc (sizeof (struct value
));
267 val
->contents
= NULL
;
268 val
->next
= all_values
;
271 val
->enclosing_type
= type
;
272 VALUE_LVAL (val
) = not_lval
;
273 val
->location
.address
= 0;
274 VALUE_FRAME_ID (val
) = null_frame_id
;
278 VALUE_REGNUM (val
) = -1;
280 val
->optimized_out
= 0;
281 val
->embedded_offset
= 0;
282 val
->pointed_to_offset
= 0;
284 val
->initialized
= 1; /* Default to initialized. */
286 /* Values start out on the all_values chain. */
287 val
->reference_count
= 1;
292 /* Allocate the contents of VAL if it has not been allocated yet. */
295 allocate_value_contents (struct value
*val
)
298 val
->contents
= (gdb_byte
*) xzalloc (TYPE_LENGTH (val
->enclosing_type
));
301 /* Allocate a value and its contents for type TYPE. */
304 allocate_value (struct type
*type
)
306 struct value
*val
= allocate_value_lazy (type
);
308 allocate_value_contents (val
);
313 /* Allocate a value that has the correct length
314 for COUNT repetitions of type TYPE. */
317 allocate_repeat_value (struct type
*type
, int count
)
319 int low_bound
= current_language
->string_lower_bound
; /* ??? */
320 /* FIXME-type-allocation: need a way to free this type when we are
322 struct type
*array_type
323 = lookup_array_range_type (type
, low_bound
, count
+ low_bound
- 1);
325 return allocate_value (array_type
);
329 allocate_computed_value (struct type
*type
,
330 struct lval_funcs
*funcs
,
333 struct value
*v
= allocate_value (type
);
335 VALUE_LVAL (v
) = lval_computed
;
336 v
->location
.computed
.funcs
= funcs
;
337 v
->location
.computed
.closure
= closure
;
338 set_value_lazy (v
, 1);
343 /* Accessor methods. */
346 value_next (struct value
*value
)
352 value_type (struct value
*value
)
357 deprecated_set_value_type (struct value
*value
, struct type
*type
)
363 value_offset (struct value
*value
)
365 return value
->offset
;
368 set_value_offset (struct value
*value
, int offset
)
370 value
->offset
= offset
;
374 value_bitpos (struct value
*value
)
376 return value
->bitpos
;
379 set_value_bitpos (struct value
*value
, int bit
)
385 value_bitsize (struct value
*value
)
387 return value
->bitsize
;
390 set_value_bitsize (struct value
*value
, int bit
)
392 value
->bitsize
= bit
;
396 value_parent (struct value
*value
)
398 return value
->parent
;
402 value_contents_raw (struct value
*value
)
404 allocate_value_contents (value
);
405 return value
->contents
+ value
->embedded_offset
;
409 value_contents_all_raw (struct value
*value
)
411 allocate_value_contents (value
);
412 return value
->contents
;
416 value_enclosing_type (struct value
*value
)
418 return value
->enclosing_type
;
422 value_contents_all (struct value
*value
)
425 value_fetch_lazy (value
);
426 return value
->contents
;
430 value_lazy (struct value
*value
)
436 set_value_lazy (struct value
*value
, int val
)
442 value_stack (struct value
*value
)
448 set_value_stack (struct value
*value
, int val
)
454 value_contents (struct value
*value
)
456 return value_contents_writeable (value
);
460 value_contents_writeable (struct value
*value
)
463 value_fetch_lazy (value
);
464 return value_contents_raw (value
);
467 /* Return non-zero if VAL1 and VAL2 have the same contents. Note that
468 this function is different from value_equal; in C the operator ==
469 can return 0 even if the two values being compared are equal. */
472 value_contents_equal (struct value
*val1
, struct value
*val2
)
478 type1
= check_typedef (value_type (val1
));
479 type2
= check_typedef (value_type (val2
));
480 len
= TYPE_LENGTH (type1
);
481 if (len
!= TYPE_LENGTH (type2
))
484 return (memcmp (value_contents (val1
), value_contents (val2
), len
) == 0);
488 value_optimized_out (struct value
*value
)
490 return value
->optimized_out
;
494 set_value_optimized_out (struct value
*value
, int val
)
496 value
->optimized_out
= val
;
500 value_embedded_offset (struct value
*value
)
502 return value
->embedded_offset
;
506 set_value_embedded_offset (struct value
*value
, int val
)
508 value
->embedded_offset
= val
;
512 value_pointed_to_offset (struct value
*value
)
514 return value
->pointed_to_offset
;
518 set_value_pointed_to_offset (struct value
*value
, int val
)
520 value
->pointed_to_offset
= val
;
524 value_computed_funcs (struct value
*v
)
526 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
528 return v
->location
.computed
.funcs
;
532 value_computed_closure (struct value
*v
)
534 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
536 return v
->location
.computed
.closure
;
540 deprecated_value_lval_hack (struct value
*value
)
546 value_address (struct value
*value
)
548 if (value
->lval
== lval_internalvar
549 || value
->lval
== lval_internalvar_component
)
551 return value
->location
.address
+ value
->offset
;
555 value_raw_address (struct value
*value
)
557 if (value
->lval
== lval_internalvar
558 || value
->lval
== lval_internalvar_component
)
560 return value
->location
.address
;
564 set_value_address (struct value
*value
, CORE_ADDR addr
)
566 gdb_assert (value
->lval
!= lval_internalvar
567 && value
->lval
!= lval_internalvar_component
);
568 value
->location
.address
= addr
;
571 struct internalvar
**
572 deprecated_value_internalvar_hack (struct value
*value
)
574 return &value
->location
.internalvar
;
578 deprecated_value_frame_id_hack (struct value
*value
)
580 return &value
->frame_id
;
584 deprecated_value_regnum_hack (struct value
*value
)
586 return &value
->regnum
;
590 deprecated_value_modifiable (struct value
*value
)
592 return value
->modifiable
;
595 deprecated_set_value_modifiable (struct value
*value
, int modifiable
)
597 value
->modifiable
= modifiable
;
600 /* Return a mark in the value chain. All values allocated after the
601 mark is obtained (except for those released) are subject to being freed
602 if a subsequent value_free_to_mark is passed the mark. */
609 /* Take a reference to VAL. VAL will not be deallocated until all
610 references are released. */
613 value_incref (struct value
*val
)
615 val
->reference_count
++;
618 /* Release a reference to VAL, which was acquired with value_incref.
619 This function is also called to deallocate values from the value
623 value_free (struct value
*val
)
627 gdb_assert (val
->reference_count
> 0);
628 val
->reference_count
--;
629 if (val
->reference_count
> 0)
632 /* If there's an associated parent value, drop our reference to
634 if (val
->parent
!= NULL
)
635 value_free (val
->parent
);
637 if (VALUE_LVAL (val
) == lval_computed
)
639 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
641 if (funcs
->free_closure
)
642 funcs
->free_closure (val
);
645 xfree (val
->contents
);
650 /* Free all values allocated since MARK was obtained by value_mark
651 (except for those released). */
653 value_free_to_mark (struct value
*mark
)
658 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
666 /* Free all the values that have been allocated (except for those released).
667 Call after each command, successful or not.
668 In practice this is called before each command, which is sufficient. */
671 free_all_values (void)
676 for (val
= all_values
; val
; val
= next
)
685 /* Remove VAL from the chain all_values
686 so it will not be freed automatically. */
689 release_value (struct value
*val
)
693 if (all_values
== val
)
695 all_values
= val
->next
;
699 for (v
= all_values
; v
; v
= v
->next
)
709 /* Release all values up to mark */
711 value_release_to_mark (struct value
*mark
)
716 for (val
= next
= all_values
; next
; next
= next
->next
)
717 if (next
->next
== mark
)
719 all_values
= next
->next
;
727 /* Return a copy of the value ARG.
728 It contains the same contents, for same memory address,
729 but it's a different block of storage. */
732 value_copy (struct value
*arg
)
734 struct type
*encl_type
= value_enclosing_type (arg
);
737 if (value_lazy (arg
))
738 val
= allocate_value_lazy (encl_type
);
740 val
= allocate_value (encl_type
);
741 val
->type
= arg
->type
;
742 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
743 val
->location
= arg
->location
;
744 val
->offset
= arg
->offset
;
745 val
->bitpos
= arg
->bitpos
;
746 val
->bitsize
= arg
->bitsize
;
747 VALUE_FRAME_ID (val
) = VALUE_FRAME_ID (arg
);
748 VALUE_REGNUM (val
) = VALUE_REGNUM (arg
);
749 val
->lazy
= arg
->lazy
;
750 val
->optimized_out
= arg
->optimized_out
;
751 val
->embedded_offset
= value_embedded_offset (arg
);
752 val
->pointed_to_offset
= arg
->pointed_to_offset
;
753 val
->modifiable
= arg
->modifiable
;
754 if (!value_lazy (val
))
756 memcpy (value_contents_all_raw (val
), value_contents_all_raw (arg
),
757 TYPE_LENGTH (value_enclosing_type (arg
)));
760 val
->parent
= arg
->parent
;
762 value_incref (val
->parent
);
763 if (VALUE_LVAL (val
) == lval_computed
)
765 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
767 if (funcs
->copy_closure
)
768 val
->location
.computed
.closure
= funcs
->copy_closure (val
);
774 set_value_component_location (struct value
*component
, struct value
*whole
)
776 if (VALUE_LVAL (whole
) == lval_internalvar
)
777 VALUE_LVAL (component
) = lval_internalvar_component
;
779 VALUE_LVAL (component
) = VALUE_LVAL (whole
);
781 component
->location
= whole
->location
;
782 if (VALUE_LVAL (whole
) == lval_computed
)
784 struct lval_funcs
*funcs
= whole
->location
.computed
.funcs
;
786 if (funcs
->copy_closure
)
787 component
->location
.computed
.closure
= funcs
->copy_closure (whole
);
792 /* Access to the value history. */
794 /* Record a new value in the value history.
795 Returns the absolute history index of the entry.
796 Result of -1 indicates the value was not saved; otherwise it is the
797 value history index of this new item. */
800 record_latest_value (struct value
*val
)
804 /* We don't want this value to have anything to do with the inferior anymore.
805 In particular, "set $1 = 50" should not affect the variable from which
806 the value was taken, and fast watchpoints should be able to assume that
807 a value on the value history never changes. */
808 if (value_lazy (val
))
809 value_fetch_lazy (val
);
810 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
811 from. This is a bit dubious, because then *&$1 does not just return $1
812 but the current contents of that location. c'est la vie... */
816 /* Here we treat value_history_count as origin-zero
817 and applying to the value being stored now. */
819 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
822 struct value_history_chunk
*new
823 = (struct value_history_chunk
*)
825 xmalloc (sizeof (struct value_history_chunk
));
826 memset (new->values
, 0, sizeof new->values
);
827 new->next
= value_history_chain
;
828 value_history_chain
= new;
831 value_history_chain
->values
[i
] = val
;
833 /* Now we regard value_history_count as origin-one
834 and applying to the value just stored. */
836 return ++value_history_count
;
839 /* Return a copy of the value in the history with sequence number NUM. */
842 access_value_history (int num
)
844 struct value_history_chunk
*chunk
;
849 absnum
+= value_history_count
;
854 error (_("The history is empty."));
856 error (_("There is only one value in the history."));
858 error (_("History does not go back to $$%d."), -num
);
860 if (absnum
> value_history_count
)
861 error (_("History has not yet reached $%d."), absnum
);
865 /* Now absnum is always absolute and origin zero. */
867 chunk
= value_history_chain
;
868 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
872 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
876 show_values (char *num_exp
, int from_tty
)
884 /* "show values +" should print from the stored position.
885 "show values <exp>" should print around value number <exp>. */
886 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
887 num
= parse_and_eval_long (num_exp
) - 5;
891 /* "show values" means print the last 10 values. */
892 num
= value_history_count
- 9;
898 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
900 struct value_print_options opts
;
902 val
= access_value_history (i
);
903 printf_filtered (("$%d = "), i
);
904 get_user_print_options (&opts
);
905 value_print (val
, gdb_stdout
, &opts
);
906 printf_filtered (("\n"));
909 /* The next "show values +" should start after what we just printed. */
912 /* Hitting just return after this command should do the same thing as
913 "show values +". If num_exp is null, this is unnecessary, since
914 "show values +" is not useful after "show values". */
915 if (from_tty
&& num_exp
)
922 /* Internal variables. These are variables within the debugger
923 that hold values assigned by debugger commands.
924 The user refers to them with a '$' prefix
925 that does not appear in the variable names stored internally. */
929 struct internalvar
*next
;
932 /* We support various different kinds of content of an internal variable.
933 enum internalvar_kind specifies the kind, and union internalvar_data
934 provides the data associated with this particular kind. */
936 enum internalvar_kind
938 /* The internal variable is empty. */
941 /* The value of the internal variable is provided directly as
942 a GDB value object. */
945 /* A fresh value is computed via a call-back routine on every
946 access to the internal variable. */
947 INTERNALVAR_MAKE_VALUE
,
949 /* The internal variable holds a GDB internal convenience function. */
950 INTERNALVAR_FUNCTION
,
952 /* The variable holds an integer value. */
955 /* The variable holds a pointer value. */
958 /* The variable holds a GDB-provided string. */
963 union internalvar_data
965 /* A value object used with INTERNALVAR_VALUE. */
968 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
969 internalvar_make_value make_value
;
971 /* The internal function used with INTERNALVAR_FUNCTION. */
974 struct internal_function
*function
;
975 /* True if this is the canonical name for the function. */
979 /* An integer value used with INTERNALVAR_INTEGER. */
982 /* If type is non-NULL, it will be used as the type to generate
983 a value for this internal variable. If type is NULL, a default
984 integer type for the architecture is used. */
989 /* A pointer value used with INTERNALVAR_POINTER. */
996 /* A string value used with INTERNALVAR_STRING. */
1001 static struct internalvar
*internalvars
;
1003 /* If the variable does not already exist create it and give it the value given.
1004 If no value is given then the default is zero. */
1006 init_if_undefined_command (char* args
, int from_tty
)
1008 struct internalvar
* intvar
;
1010 /* Parse the expression - this is taken from set_command(). */
1011 struct expression
*expr
= parse_expression (args
);
1012 register struct cleanup
*old_chain
=
1013 make_cleanup (free_current_contents
, &expr
);
1015 /* Validate the expression.
1016 Was the expression an assignment?
1017 Or even an expression at all? */
1018 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
1019 error (_("Init-if-undefined requires an assignment expression."));
1021 /* Extract the variable from the parsed expression.
1022 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
1023 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
1024 error (_("The first parameter to init-if-undefined should be a GDB variable."));
1025 intvar
= expr
->elts
[2].internalvar
;
1027 /* Only evaluate the expression if the lvalue is void.
1028 This may still fail if the expresssion is invalid. */
1029 if (intvar
->kind
== INTERNALVAR_VOID
)
1030 evaluate_expression (expr
);
1032 do_cleanups (old_chain
);
1036 /* Look up an internal variable with name NAME. NAME should not
1037 normally include a dollar sign.
1039 If the specified internal variable does not exist,
1040 the return value is NULL. */
1042 struct internalvar
*
1043 lookup_only_internalvar (const char *name
)
1045 struct internalvar
*var
;
1047 for (var
= internalvars
; var
; var
= var
->next
)
1048 if (strcmp (var
->name
, name
) == 0)
1055 /* Create an internal variable with name NAME and with a void value.
1056 NAME should not normally include a dollar sign. */
1058 struct internalvar
*
1059 create_internalvar (const char *name
)
1061 struct internalvar
*var
;
1063 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
1064 var
->name
= concat (name
, (char *)NULL
);
1065 var
->kind
= INTERNALVAR_VOID
;
1066 var
->next
= internalvars
;
1071 /* Create an internal variable with name NAME and register FUN as the
1072 function that value_of_internalvar uses to create a value whenever
1073 this variable is referenced. NAME should not normally include a
1076 struct internalvar
*
1077 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
1079 struct internalvar
*var
= create_internalvar (name
);
1081 var
->kind
= INTERNALVAR_MAKE_VALUE
;
1082 var
->u
.make_value
= fun
;
1086 /* Look up an internal variable with name NAME. NAME should not
1087 normally include a dollar sign.
1089 If the specified internal variable does not exist,
1090 one is created, with a void value. */
1092 struct internalvar
*
1093 lookup_internalvar (const char *name
)
1095 struct internalvar
*var
;
1097 var
= lookup_only_internalvar (name
);
1101 return create_internalvar (name
);
1104 /* Return current value of internal variable VAR. For variables that
1105 are not inherently typed, use a value type appropriate for GDBARCH. */
1108 value_of_internalvar (struct gdbarch
*gdbarch
, struct internalvar
*var
)
1114 case INTERNALVAR_VOID
:
1115 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1118 case INTERNALVAR_FUNCTION
:
1119 val
= allocate_value (builtin_type (gdbarch
)->internal_fn
);
1122 case INTERNALVAR_INTEGER
:
1123 if (!var
->u
.integer
.type
)
1124 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
1125 var
->u
.integer
.val
);
1127 val
= value_from_longest (var
->u
.integer
.type
, var
->u
.integer
.val
);
1130 case INTERNALVAR_POINTER
:
1131 val
= value_from_pointer (var
->u
.pointer
.type
, var
->u
.pointer
.val
);
1134 case INTERNALVAR_STRING
:
1135 val
= value_cstring (var
->u
.string
, strlen (var
->u
.string
),
1136 builtin_type (gdbarch
)->builtin_char
);
1139 case INTERNALVAR_VALUE
:
1140 val
= value_copy (var
->u
.value
);
1141 if (value_lazy (val
))
1142 value_fetch_lazy (val
);
1145 case INTERNALVAR_MAKE_VALUE
:
1146 val
= (*var
->u
.make_value
) (gdbarch
, var
);
1150 internal_error (__FILE__
, __LINE__
, "bad kind");
1153 /* Change the VALUE_LVAL to lval_internalvar so that future operations
1154 on this value go back to affect the original internal variable.
1156 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
1157 no underlying modifyable state in the internal variable.
1159 Likewise, if the variable's value is a computed lvalue, we want
1160 references to it to produce another computed lvalue, where
1161 references and assignments actually operate through the
1162 computed value's functions.
1164 This means that internal variables with computed values
1165 behave a little differently from other internal variables:
1166 assignments to them don't just replace the previous value
1167 altogether. At the moment, this seems like the behavior we
1170 if (var
->kind
!= INTERNALVAR_MAKE_VALUE
1171 && val
->lval
!= lval_computed
)
1173 VALUE_LVAL (val
) = lval_internalvar
;
1174 VALUE_INTERNALVAR (val
) = var
;
1181 get_internalvar_integer (struct internalvar
*var
, LONGEST
*result
)
1185 case INTERNALVAR_INTEGER
:
1186 *result
= var
->u
.integer
.val
;
1195 get_internalvar_function (struct internalvar
*var
,
1196 struct internal_function
**result
)
1200 case INTERNALVAR_FUNCTION
:
1201 *result
= var
->u
.fn
.function
;
1210 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1211 int bitsize
, struct value
*newval
)
1217 case INTERNALVAR_VALUE
:
1218 addr
= value_contents_writeable (var
->u
.value
);
1221 modify_field (value_type (var
->u
.value
), addr
+ offset
,
1222 value_as_long (newval
), bitpos
, bitsize
);
1224 memcpy (addr
+ offset
, value_contents (newval
),
1225 TYPE_LENGTH (value_type (newval
)));
1229 /* We can never get a component of any other kind. */
1230 internal_error (__FILE__
, __LINE__
, "set_internalvar_component");
1235 set_internalvar (struct internalvar
*var
, struct value
*val
)
1237 enum internalvar_kind new_kind
;
1238 union internalvar_data new_data
= { 0 };
1240 if (var
->kind
== INTERNALVAR_FUNCTION
&& var
->u
.fn
.canonical
)
1241 error (_("Cannot overwrite convenience function %s"), var
->name
);
1243 /* Prepare new contents. */
1244 switch (TYPE_CODE (check_typedef (value_type (val
))))
1246 case TYPE_CODE_VOID
:
1247 new_kind
= INTERNALVAR_VOID
;
1250 case TYPE_CODE_INTERNAL_FUNCTION
:
1251 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1252 new_kind
= INTERNALVAR_FUNCTION
;
1253 get_internalvar_function (VALUE_INTERNALVAR (val
),
1254 &new_data
.fn
.function
);
1255 /* Copies created here are never canonical. */
1259 new_kind
= INTERNALVAR_INTEGER
;
1260 new_data
.integer
.type
= value_type (val
);
1261 new_data
.integer
.val
= value_as_long (val
);
1265 new_kind
= INTERNALVAR_POINTER
;
1266 new_data
.pointer
.type
= value_type (val
);
1267 new_data
.pointer
.val
= value_as_address (val
);
1271 new_kind
= INTERNALVAR_VALUE
;
1272 new_data
.value
= value_copy (val
);
1273 new_data
.value
->modifiable
= 1;
1275 /* Force the value to be fetched from the target now, to avoid problems
1276 later when this internalvar is referenced and the target is gone or
1278 if (value_lazy (new_data
.value
))
1279 value_fetch_lazy (new_data
.value
);
1281 /* Release the value from the value chain to prevent it from being
1282 deleted by free_all_values. From here on this function should not
1283 call error () until new_data is installed into the var->u to avoid
1285 release_value (new_data
.value
);
1289 /* Clean up old contents. */
1290 clear_internalvar (var
);
1293 var
->kind
= new_kind
;
1295 /* End code which must not call error(). */
1299 set_internalvar_integer (struct internalvar
*var
, LONGEST l
)
1301 /* Clean up old contents. */
1302 clear_internalvar (var
);
1304 var
->kind
= INTERNALVAR_INTEGER
;
1305 var
->u
.integer
.type
= NULL
;
1306 var
->u
.integer
.val
= l
;
1310 set_internalvar_string (struct internalvar
*var
, const char *string
)
1312 /* Clean up old contents. */
1313 clear_internalvar (var
);
1315 var
->kind
= INTERNALVAR_STRING
;
1316 var
->u
.string
= xstrdup (string
);
1320 set_internalvar_function (struct internalvar
*var
, struct internal_function
*f
)
1322 /* Clean up old contents. */
1323 clear_internalvar (var
);
1325 var
->kind
= INTERNALVAR_FUNCTION
;
1326 var
->u
.fn
.function
= f
;
1327 var
->u
.fn
.canonical
= 1;
1328 /* Variables installed here are always the canonical version. */
1332 clear_internalvar (struct internalvar
*var
)
1334 /* Clean up old contents. */
1337 case INTERNALVAR_VALUE
:
1338 value_free (var
->u
.value
);
1341 case INTERNALVAR_STRING
:
1342 xfree (var
->u
.string
);
1349 /* Reset to void kind. */
1350 var
->kind
= INTERNALVAR_VOID
;
1354 internalvar_name (struct internalvar
*var
)
1359 static struct internal_function
*
1360 create_internal_function (const char *name
,
1361 internal_function_fn handler
, void *cookie
)
1363 struct internal_function
*ifn
= XNEW (struct internal_function
);
1365 ifn
->name
= xstrdup (name
);
1366 ifn
->handler
= handler
;
1367 ifn
->cookie
= cookie
;
1372 value_internal_function_name (struct value
*val
)
1374 struct internal_function
*ifn
;
1377 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1378 result
= get_internalvar_function (VALUE_INTERNALVAR (val
), &ifn
);
1379 gdb_assert (result
);
1385 call_internal_function (struct gdbarch
*gdbarch
,
1386 const struct language_defn
*language
,
1387 struct value
*func
, int argc
, struct value
**argv
)
1389 struct internal_function
*ifn
;
1392 gdb_assert (VALUE_LVAL (func
) == lval_internalvar
);
1393 result
= get_internalvar_function (VALUE_INTERNALVAR (func
), &ifn
);
1394 gdb_assert (result
);
1396 return (*ifn
->handler
) (gdbarch
, language
, ifn
->cookie
, argc
, argv
);
1399 /* The 'function' command. This does nothing -- it is just a
1400 placeholder to let "help function NAME" work. This is also used as
1401 the implementation of the sub-command that is created when
1402 registering an internal function. */
1404 function_command (char *command
, int from_tty
)
1409 /* Clean up if an internal function's command is destroyed. */
1411 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1417 /* Add a new internal function. NAME is the name of the function; DOC
1418 is a documentation string describing the function. HANDLER is
1419 called when the function is invoked. COOKIE is an arbitrary
1420 pointer which is passed to HANDLER and is intended for "user
1423 add_internal_function (const char *name
, const char *doc
,
1424 internal_function_fn handler
, void *cookie
)
1426 struct cmd_list_element
*cmd
;
1427 struct internal_function
*ifn
;
1428 struct internalvar
*var
= lookup_internalvar (name
);
1430 ifn
= create_internal_function (name
, handler
, cookie
);
1431 set_internalvar_function (var
, ifn
);
1433 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1435 cmd
->destroyer
= function_destroyer
;
1438 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1439 prevent cycles / duplicates. */
1442 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1443 htab_t copied_types
)
1445 if (TYPE_OBJFILE (value
->type
) == objfile
)
1446 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1448 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1449 value
->enclosing_type
= copy_type_recursive (objfile
,
1450 value
->enclosing_type
,
1454 /* Likewise for internal variable VAR. */
1457 preserve_one_internalvar (struct internalvar
*var
, struct objfile
*objfile
,
1458 htab_t copied_types
)
1462 case INTERNALVAR_INTEGER
:
1463 if (var
->u
.integer
.type
&& TYPE_OBJFILE (var
->u
.integer
.type
) == objfile
)
1465 = copy_type_recursive (objfile
, var
->u
.integer
.type
, copied_types
);
1468 case INTERNALVAR_POINTER
:
1469 if (TYPE_OBJFILE (var
->u
.pointer
.type
) == objfile
)
1471 = copy_type_recursive (objfile
, var
->u
.pointer
.type
, copied_types
);
1474 case INTERNALVAR_VALUE
:
1475 preserve_one_value (var
->u
.value
, objfile
, copied_types
);
1480 /* Update the internal variables and value history when OBJFILE is
1481 discarded; we must copy the types out of the objfile. New global types
1482 will be created for every convenience variable which currently points to
1483 this objfile's types, and the convenience variables will be adjusted to
1484 use the new global types. */
1487 preserve_values (struct objfile
*objfile
)
1489 htab_t copied_types
;
1490 struct value_history_chunk
*cur
;
1491 struct internalvar
*var
;
1494 /* Create the hash table. We allocate on the objfile's obstack, since
1495 it is soon to be deleted. */
1496 copied_types
= create_copied_types_hash (objfile
);
1498 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1499 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1501 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1503 for (var
= internalvars
; var
; var
= var
->next
)
1504 preserve_one_internalvar (var
, objfile
, copied_types
);
1506 preserve_python_values (objfile
, copied_types
);
1508 htab_delete (copied_types
);
1512 show_convenience (char *ignore
, int from_tty
)
1514 struct gdbarch
*gdbarch
= get_current_arch ();
1515 struct internalvar
*var
;
1517 struct value_print_options opts
;
1519 get_user_print_options (&opts
);
1520 for (var
= internalvars
; var
; var
= var
->next
)
1526 printf_filtered (("$%s = "), var
->name
);
1527 value_print (value_of_internalvar (gdbarch
, var
), gdb_stdout
,
1529 printf_filtered (("\n"));
1532 printf_unfiltered (_("\
1533 No debugger convenience variables now defined.\n\
1534 Convenience variables have names starting with \"$\";\n\
1535 use \"set\" as in \"set $foo = 5\" to define them.\n"));
1538 /* Extract a value as a C number (either long or double).
1539 Knows how to convert fixed values to double, or
1540 floating values to long.
1541 Does not deallocate the value. */
1544 value_as_long (struct value
*val
)
1546 /* This coerces arrays and functions, which is necessary (e.g.
1547 in disassemble_command). It also dereferences references, which
1548 I suspect is the most logical thing to do. */
1549 val
= coerce_array (val
);
1550 return unpack_long (value_type (val
), value_contents (val
));
1554 value_as_double (struct value
*val
)
1559 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1561 error (_("Invalid floating value found in program."));
1565 /* Extract a value as a C pointer. Does not deallocate the value.
1566 Note that val's type may not actually be a pointer; value_as_long
1567 handles all the cases. */
1569 value_as_address (struct value
*val
)
1571 struct gdbarch
*gdbarch
= get_type_arch (value_type (val
));
1573 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1574 whether we want this to be true eventually. */
1576 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1577 non-address (e.g. argument to "signal", "info break", etc.), or
1578 for pointers to char, in which the low bits *are* significant. */
1579 return gdbarch_addr_bits_remove (gdbarch
, value_as_long (val
));
1582 /* There are several targets (IA-64, PowerPC, and others) which
1583 don't represent pointers to functions as simply the address of
1584 the function's entry point. For example, on the IA-64, a
1585 function pointer points to a two-word descriptor, generated by
1586 the linker, which contains the function's entry point, and the
1587 value the IA-64 "global pointer" register should have --- to
1588 support position-independent code. The linker generates
1589 descriptors only for those functions whose addresses are taken.
1591 On such targets, it's difficult for GDB to convert an arbitrary
1592 function address into a function pointer; it has to either find
1593 an existing descriptor for that function, or call malloc and
1594 build its own. On some targets, it is impossible for GDB to
1595 build a descriptor at all: the descriptor must contain a jump
1596 instruction; data memory cannot be executed; and code memory
1599 Upon entry to this function, if VAL is a value of type `function'
1600 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1601 value_address (val) is the address of the function. This is what
1602 you'll get if you evaluate an expression like `main'. The call
1603 to COERCE_ARRAY below actually does all the usual unary
1604 conversions, which includes converting values of type `function'
1605 to `pointer to function'. This is the challenging conversion
1606 discussed above. Then, `unpack_long' will convert that pointer
1607 back into an address.
1609 So, suppose the user types `disassemble foo' on an architecture
1610 with a strange function pointer representation, on which GDB
1611 cannot build its own descriptors, and suppose further that `foo'
1612 has no linker-built descriptor. The address->pointer conversion
1613 will signal an error and prevent the command from running, even
1614 though the next step would have been to convert the pointer
1615 directly back into the same address.
1617 The following shortcut avoids this whole mess. If VAL is a
1618 function, just return its address directly. */
1619 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
1620 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
1621 return value_address (val
);
1623 val
= coerce_array (val
);
1625 /* Some architectures (e.g. Harvard), map instruction and data
1626 addresses onto a single large unified address space. For
1627 instance: An architecture may consider a large integer in the
1628 range 0x10000000 .. 0x1000ffff to already represent a data
1629 addresses (hence not need a pointer to address conversion) while
1630 a small integer would still need to be converted integer to
1631 pointer to address. Just assume such architectures handle all
1632 integer conversions in a single function. */
1636 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1637 must admonish GDB hackers to make sure its behavior matches the
1638 compiler's, whenever possible.
1640 In general, I think GDB should evaluate expressions the same way
1641 the compiler does. When the user copies an expression out of
1642 their source code and hands it to a `print' command, they should
1643 get the same value the compiler would have computed. Any
1644 deviation from this rule can cause major confusion and annoyance,
1645 and needs to be justified carefully. In other words, GDB doesn't
1646 really have the freedom to do these conversions in clever and
1649 AndrewC pointed out that users aren't complaining about how GDB
1650 casts integers to pointers; they are complaining that they can't
1651 take an address from a disassembly listing and give it to `x/i'.
1652 This is certainly important.
1654 Adding an architecture method like integer_to_address() certainly
1655 makes it possible for GDB to "get it right" in all circumstances
1656 --- the target has complete control over how things get done, so
1657 people can Do The Right Thing for their target without breaking
1658 anyone else. The standard doesn't specify how integers get
1659 converted to pointers; usually, the ABI doesn't either, but
1660 ABI-specific code is a more reasonable place to handle it. */
1662 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
1663 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
1664 && gdbarch_integer_to_address_p (gdbarch
))
1665 return gdbarch_integer_to_address (gdbarch
, value_type (val
),
1666 value_contents (val
));
1668 return unpack_long (value_type (val
), value_contents (val
));
1672 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1673 as a long, or as a double, assuming the raw data is described
1674 by type TYPE. Knows how to convert different sizes of values
1675 and can convert between fixed and floating point. We don't assume
1676 any alignment for the raw data. Return value is in host byte order.
1678 If you want functions and arrays to be coerced to pointers, and
1679 references to be dereferenced, call value_as_long() instead.
1681 C++: It is assumed that the front-end has taken care of
1682 all matters concerning pointers to members. A pointer
1683 to member which reaches here is considered to be equivalent
1684 to an INT (or some size). After all, it is only an offset. */
1687 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
1689 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1690 enum type_code code
= TYPE_CODE (type
);
1691 int len
= TYPE_LENGTH (type
);
1692 int nosign
= TYPE_UNSIGNED (type
);
1696 case TYPE_CODE_TYPEDEF
:
1697 return unpack_long (check_typedef (type
), valaddr
);
1698 case TYPE_CODE_ENUM
:
1699 case TYPE_CODE_FLAGS
:
1700 case TYPE_CODE_BOOL
:
1702 case TYPE_CODE_CHAR
:
1703 case TYPE_CODE_RANGE
:
1704 case TYPE_CODE_MEMBERPTR
:
1706 return extract_unsigned_integer (valaddr
, len
, byte_order
);
1708 return extract_signed_integer (valaddr
, len
, byte_order
);
1711 return extract_typed_floating (valaddr
, type
);
1713 case TYPE_CODE_DECFLOAT
:
1714 /* libdecnumber has a function to convert from decimal to integer, but
1715 it doesn't work when the decimal number has a fractional part. */
1716 return decimal_to_doublest (valaddr
, len
, byte_order
);
1720 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1721 whether we want this to be true eventually. */
1722 return extract_typed_address (valaddr
, type
);
1725 error (_("Value can't be converted to integer."));
1727 return 0; /* Placate lint. */
1730 /* Return a double value from the specified type and address.
1731 INVP points to an int which is set to 0 for valid value,
1732 1 for invalid value (bad float format). In either case,
1733 the returned double is OK to use. Argument is in target
1734 format, result is in host format. */
1737 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
1739 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1740 enum type_code code
;
1744 *invp
= 0; /* Assume valid. */
1745 CHECK_TYPEDEF (type
);
1746 code
= TYPE_CODE (type
);
1747 len
= TYPE_LENGTH (type
);
1748 nosign
= TYPE_UNSIGNED (type
);
1749 if (code
== TYPE_CODE_FLT
)
1751 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1752 floating-point value was valid (using the macro
1753 INVALID_FLOAT). That test/macro have been removed.
1755 It turns out that only the VAX defined this macro and then
1756 only in a non-portable way. Fixing the portability problem
1757 wouldn't help since the VAX floating-point code is also badly
1758 bit-rotten. The target needs to add definitions for the
1759 methods gdbarch_float_format and gdbarch_double_format - these
1760 exactly describe the target floating-point format. The
1761 problem here is that the corresponding floatformat_vax_f and
1762 floatformat_vax_d values these methods should be set to are
1763 also not defined either. Oops!
1765 Hopefully someone will add both the missing floatformat
1766 definitions and the new cases for floatformat_is_valid (). */
1768 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
1774 return extract_typed_floating (valaddr
, type
);
1776 else if (code
== TYPE_CODE_DECFLOAT
)
1777 return decimal_to_doublest (valaddr
, len
, byte_order
);
1780 /* Unsigned -- be sure we compensate for signed LONGEST. */
1781 return (ULONGEST
) unpack_long (type
, valaddr
);
1785 /* Signed -- we are OK with unpack_long. */
1786 return unpack_long (type
, valaddr
);
1790 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1791 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1792 We don't assume any alignment for the raw data. Return value is in
1795 If you want functions and arrays to be coerced to pointers, and
1796 references to be dereferenced, call value_as_address() instead.
1798 C++: It is assumed that the front-end has taken care of
1799 all matters concerning pointers to members. A pointer
1800 to member which reaches here is considered to be equivalent
1801 to an INT (or some size). After all, it is only an offset. */
1804 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
1806 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1807 whether we want this to be true eventually. */
1808 return unpack_long (type
, valaddr
);
1812 /* Get the value of the FIELDN'th field (which must be static) of
1813 TYPE. Return NULL if the field doesn't exist or has been
1817 value_static_field (struct type
*type
, int fieldno
)
1819 struct value
*retval
;
1821 if (TYPE_FIELD_LOC_KIND (type
, fieldno
) == FIELD_LOC_KIND_PHYSADDR
)
1823 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
1824 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1828 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1829 /*TYPE_FIELD_NAME (type, fieldno);*/
1830 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1834 /* With some compilers, e.g. HP aCC, static data members are
1835 reported as non-debuggable symbols */
1836 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
,
1843 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
1844 SYMBOL_VALUE_ADDRESS (msym
));
1849 /* SYM should never have a SYMBOL_CLASS which will require
1850 read_var_value to use the FRAME parameter. */
1851 if (symbol_read_needs_frame (sym
))
1852 warning (_("static field's value depends on the current "
1853 "frame - bad debug info?"));
1854 retval
= read_var_value (sym
, NULL
);
1856 if (retval
&& VALUE_LVAL (retval
) == lval_memory
)
1857 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
),
1858 value_address (retval
));
1863 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1864 You have to be careful here, since the size of the data area for the value
1865 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1866 than the old enclosing type, you have to allocate more space for the data.
1867 The return value is a pointer to the new version of this value structure. */
1870 value_change_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
1872 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
1874 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
1876 val
->enclosing_type
= new_encl_type
;
1880 /* Given a value ARG1 (offset by OFFSET bytes)
1881 of a struct or union type ARG_TYPE,
1882 extract and return the value of one of its (non-static) fields.
1883 FIELDNO says which field. */
1886 value_primitive_field (struct value
*arg1
, int offset
,
1887 int fieldno
, struct type
*arg_type
)
1892 CHECK_TYPEDEF (arg_type
);
1893 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
1895 /* Call check_typedef on our type to make sure that, if TYPE
1896 is a TYPE_CODE_TYPEDEF, its length is set to the length
1897 of the target type instead of zero. However, we do not
1898 replace the typedef type by the target type, because we want
1899 to keep the typedef in order to be able to print the type
1900 description correctly. */
1901 check_typedef (type
);
1903 /* Handle packed fields */
1905 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
1907 /* Create a new value for the bitfield, with bitpos and bitsize
1908 set. If possible, arrange offset and bitpos so that we can
1909 do a single aligned read of the size of the containing type.
1910 Otherwise, adjust offset to the byte containing the first
1911 bit. Assume that the address, offset, and embedded offset
1912 are sufficiently aligned. */
1913 int bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
);
1914 int container_bitsize
= TYPE_LENGTH (type
) * 8;
1916 v
= allocate_value_lazy (type
);
1917 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
1918 if ((bitpos
% container_bitsize
) + v
->bitsize
<= container_bitsize
1919 && TYPE_LENGTH (type
) <= (int) sizeof (LONGEST
))
1920 v
->bitpos
= bitpos
% container_bitsize
;
1922 v
->bitpos
= bitpos
% 8;
1923 v
->offset
= value_embedded_offset (arg1
)
1924 + (bitpos
- v
->bitpos
) / 8;
1926 value_incref (v
->parent
);
1927 if (!value_lazy (arg1
))
1928 value_fetch_lazy (v
);
1930 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
1932 /* This field is actually a base subobject, so preserve the
1933 entire object's contents for later references to virtual
1936 /* Lazy register values with offsets are not supported. */
1937 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1938 value_fetch_lazy (arg1
);
1940 if (value_lazy (arg1
))
1941 v
= allocate_value_lazy (value_enclosing_type (arg1
));
1944 v
= allocate_value (value_enclosing_type (arg1
));
1945 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
1946 TYPE_LENGTH (value_enclosing_type (arg1
)));
1949 v
->offset
= value_offset (arg1
);
1950 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
1951 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
1955 /* Plain old data member */
1956 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1958 /* Lazy register values with offsets are not supported. */
1959 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1960 value_fetch_lazy (arg1
);
1962 if (value_lazy (arg1
))
1963 v
= allocate_value_lazy (type
);
1966 v
= allocate_value (type
);
1967 memcpy (value_contents_raw (v
),
1968 value_contents_raw (arg1
) + offset
,
1969 TYPE_LENGTH (type
));
1971 v
->offset
= (value_offset (arg1
) + offset
1972 + value_embedded_offset (arg1
));
1974 set_value_component_location (v
, arg1
);
1975 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
1976 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
1980 /* Given a value ARG1 of a struct or union type,
1981 extract and return the value of one of its (non-static) fields.
1982 FIELDNO says which field. */
1985 value_field (struct value
*arg1
, int fieldno
)
1987 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
1990 /* Return a non-virtual function as a value.
1991 F is the list of member functions which contains the desired method.
1992 J is an index into F which provides the desired method.
1994 We only use the symbol for its address, so be happy with either a
1995 full symbol or a minimal symbol.
1999 value_fn_field (struct value
**arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
2003 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
2004 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
2006 struct minimal_symbol
*msym
;
2008 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
2015 gdb_assert (sym
== NULL
);
2016 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
2021 v
= allocate_value (ftype
);
2024 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
2028 /* The minimal symbol might point to a function descriptor;
2029 resolve it to the actual code address instead. */
2030 struct objfile
*objfile
= msymbol_objfile (msym
);
2031 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
2033 set_value_address (v
,
2034 gdbarch_convert_from_func_ptr_addr
2035 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
2040 if (type
!= value_type (*arg1p
))
2041 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
2042 value_addr (*arg1p
)));
2044 /* Move the `this' pointer according to the offset.
2045 VALUE_OFFSET (*arg1p) += offset;
2053 /* Unpack a bitfield of the specified FIELD_TYPE, from the anonymous
2054 object at VALADDR. The bitfield starts at BITPOS bits and contains
2057 Extracting bits depends on endianness of the machine. Compute the
2058 number of least significant bits to discard. For big endian machines,
2059 we compute the total number of bits in the anonymous object, subtract
2060 off the bit count from the MSB of the object to the MSB of the
2061 bitfield, then the size of the bitfield, which leaves the LSB discard
2062 count. For little endian machines, the discard count is simply the
2063 number of bits from the LSB of the anonymous object to the LSB of the
2066 If the field is signed, we also do sign extension. */
2069 unpack_bits_as_long (struct type
*field_type
, const gdb_byte
*valaddr
,
2070 int bitpos
, int bitsize
)
2072 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (field_type
));
2078 /* Read the minimum number of bytes required; there may not be
2079 enough bytes to read an entire ULONGEST. */
2080 CHECK_TYPEDEF (field_type
);
2082 bytes_read
= ((bitpos
% 8) + bitsize
+ 7) / 8;
2084 bytes_read
= TYPE_LENGTH (field_type
);
2086 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8,
2087 bytes_read
, byte_order
);
2089 /* Extract bits. See comment above. */
2091 if (gdbarch_bits_big_endian (get_type_arch (field_type
)))
2092 lsbcount
= (bytes_read
* 8 - bitpos
% 8 - bitsize
);
2094 lsbcount
= (bitpos
% 8);
2097 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
2098 If the field is signed, and is negative, then sign extend. */
2100 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
2102 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
2104 if (!TYPE_UNSIGNED (field_type
))
2106 if (val
& (valmask
^ (valmask
>> 1)))
2115 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
2116 VALADDR. See unpack_bits_as_long for more details. */
2119 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
2121 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
2122 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
2123 struct type
*field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
2125 return unpack_bits_as_long (field_type
, valaddr
, bitpos
, bitsize
);
2128 /* Modify the value of a bitfield. ADDR points to a block of memory in
2129 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
2130 is the desired value of the field, in host byte order. BITPOS and BITSIZE
2131 indicate which bits (in target bit order) comprise the bitfield.
2132 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS+BITSIZE <= lbits, and
2133 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
2136 modify_field (struct type
*type
, gdb_byte
*addr
,
2137 LONGEST fieldval
, int bitpos
, int bitsize
)
2139 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2141 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
2143 /* If a negative fieldval fits in the field in question, chop
2144 off the sign extension bits. */
2145 if ((~fieldval
& ~(mask
>> 1)) == 0)
2148 /* Warn if value is too big to fit in the field in question. */
2149 if (0 != (fieldval
& ~mask
))
2151 /* FIXME: would like to include fieldval in the message, but
2152 we don't have a sprintf_longest. */
2153 warning (_("Value does not fit in %d bits."), bitsize
);
2155 /* Truncate it, otherwise adjoining fields may be corrupted. */
2159 oword
= extract_unsigned_integer (addr
, sizeof oword
, byte_order
);
2161 /* Shifting for bit field depends on endianness of the target machine. */
2162 if (gdbarch_bits_big_endian (get_type_arch (type
)))
2163 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
2165 oword
&= ~(mask
<< bitpos
);
2166 oword
|= fieldval
<< bitpos
;
2168 store_unsigned_integer (addr
, sizeof oword
, byte_order
, oword
);
2171 /* Pack NUM into BUF using a target format of TYPE. */
2174 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
2176 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2179 type
= check_typedef (type
);
2180 len
= TYPE_LENGTH (type
);
2182 switch (TYPE_CODE (type
))
2185 case TYPE_CODE_CHAR
:
2186 case TYPE_CODE_ENUM
:
2187 case TYPE_CODE_FLAGS
:
2188 case TYPE_CODE_BOOL
:
2189 case TYPE_CODE_RANGE
:
2190 case TYPE_CODE_MEMBERPTR
:
2191 store_signed_integer (buf
, len
, byte_order
, num
);
2196 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2200 error (_("Unexpected type (%d) encountered for integer constant."),
2206 /* Convert C numbers into newly allocated values. */
2209 value_from_longest (struct type
*type
, LONGEST num
)
2211 struct value
*val
= allocate_value (type
);
2213 pack_long (value_contents_raw (val
), type
, num
);
2218 /* Create a value representing a pointer of type TYPE to the address
2221 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
2223 struct value
*val
= allocate_value (type
);
2225 store_typed_address (value_contents_raw (val
), check_typedef (type
), addr
);
2230 /* Create a value of type TYPE whose contents come from VALADDR, if it
2231 is non-null, and whose memory address (in the inferior) is
2235 value_from_contents_and_address (struct type
*type
,
2236 const gdb_byte
*valaddr
,
2239 struct value
*v
= allocate_value (type
);
2241 if (valaddr
== NULL
)
2242 set_value_lazy (v
, 1);
2244 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
2245 set_value_address (v
, address
);
2246 VALUE_LVAL (v
) = lval_memory
;
2251 value_from_double (struct type
*type
, DOUBLEST num
)
2253 struct value
*val
= allocate_value (type
);
2254 struct type
*base_type
= check_typedef (type
);
2255 enum type_code code
= TYPE_CODE (base_type
);
2257 if (code
== TYPE_CODE_FLT
)
2259 store_typed_floating (value_contents_raw (val
), base_type
, num
);
2262 error (_("Unexpected type encountered for floating constant."));
2268 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
2270 struct value
*val
= allocate_value (type
);
2272 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
2277 coerce_ref (struct value
*arg
)
2279 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
2281 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
2282 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
2283 unpack_pointer (value_type (arg
),
2284 value_contents (arg
)));
2289 coerce_array (struct value
*arg
)
2293 arg
= coerce_ref (arg
);
2294 type
= check_typedef (value_type (arg
));
2296 switch (TYPE_CODE (type
))
2298 case TYPE_CODE_ARRAY
:
2299 if (current_language
->c_style_arrays
)
2300 arg
= value_coerce_array (arg
);
2302 case TYPE_CODE_FUNC
:
2303 arg
= value_coerce_function (arg
);
2310 /* Return true if the function returning the specified type is using
2311 the convention of returning structures in memory (passing in the
2312 address as a hidden first parameter). */
2315 using_struct_return (struct gdbarch
*gdbarch
,
2316 struct type
*func_type
, struct type
*value_type
)
2318 enum type_code code
= TYPE_CODE (value_type
);
2320 if (code
== TYPE_CODE_ERROR
)
2321 error (_("Function return type unknown."));
2323 if (code
== TYPE_CODE_VOID
)
2324 /* A void return value is never in memory. See also corresponding
2325 code in "print_return_value". */
2328 /* Probe the architecture for the return-value convention. */
2329 return (gdbarch_return_value (gdbarch
, func_type
, value_type
,
2331 != RETURN_VALUE_REGISTER_CONVENTION
);
2334 /* Set the initialized field in a value struct. */
2337 set_value_initialized (struct value
*val
, int status
)
2339 val
->initialized
= status
;
2342 /* Return the initialized field in a value struct. */
2345 value_initialized (struct value
*val
)
2347 return val
->initialized
;
2351 _initialize_values (void)
2353 add_cmd ("convenience", no_class
, show_convenience
, _("\
2354 Debugger convenience (\"$foo\") variables.\n\
2355 These variables are created when you assign them values;\n\
2356 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2358 A few convenience variables are given values automatically:\n\
2359 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2360 \"$__\" holds the contents of the last address examined with \"x\"."),
2363 add_cmd ("values", no_class
, show_values
,
2364 _("Elements of value history around item number IDX (or last ten)."),
2367 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2368 Initialize a convenience variable if necessary.\n\
2369 init-if-undefined VARIABLE = EXPRESSION\n\
2370 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2371 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2372 VARIABLE is already initialized."));
2374 add_prefix_cmd ("function", no_class
, function_command
, _("\
2375 Placeholder command for showing help on convenience functions."),
2376 &functionlist
, "function ", 0, &cmdlist
);