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 (const struct value
*value
)
357 deprecated_set_value_type (struct value
*value
, struct type
*type
)
363 value_offset (const struct value
*value
)
365 return value
->offset
;
368 set_value_offset (struct value
*value
, int offset
)
370 value
->offset
= offset
;
374 value_bitpos (const struct value
*value
)
376 return value
->bitpos
;
379 set_value_bitpos (struct value
*value
, int bit
)
385 value_bitsize (const 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 require_not_optimized_out (struct value
*value
)
424 if (value
->optimized_out
)
425 error (_("value has been optimized out"));
429 value_contents_for_printing (struct value
*value
)
432 value_fetch_lazy (value
);
433 return value
->contents
;
437 value_contents_all (struct value
*value
)
439 const gdb_byte
*result
= value_contents_for_printing (value
);
440 require_not_optimized_out (value
);
445 value_lazy (struct value
*value
)
451 set_value_lazy (struct value
*value
, int val
)
457 value_stack (struct value
*value
)
463 set_value_stack (struct value
*value
, int val
)
469 value_contents (struct value
*value
)
471 const gdb_byte
*result
= value_contents_writeable (value
);
472 require_not_optimized_out (value
);
477 value_contents_writeable (struct value
*value
)
480 value_fetch_lazy (value
);
481 return value_contents_raw (value
);
484 /* Return non-zero if VAL1 and VAL2 have the same contents. Note that
485 this function is different from value_equal; in C the operator ==
486 can return 0 even if the two values being compared are equal. */
489 value_contents_equal (struct value
*val1
, struct value
*val2
)
495 type1
= check_typedef (value_type (val1
));
496 type2
= check_typedef (value_type (val2
));
497 len
= TYPE_LENGTH (type1
);
498 if (len
!= TYPE_LENGTH (type2
))
501 return (memcmp (value_contents (val1
), value_contents (val2
), len
) == 0);
505 value_optimized_out (struct value
*value
)
507 return value
->optimized_out
;
511 set_value_optimized_out (struct value
*value
, int val
)
513 value
->optimized_out
= val
;
517 value_entirely_optimized_out (const struct value
*value
)
519 if (!value
->optimized_out
)
521 if (value
->lval
!= lval_computed
522 || !value
->location
.computed
.funcs
->check_validity
)
524 return !value
->location
.computed
.funcs
->check_any_valid (value
);
528 value_bits_valid (const struct value
*value
, int offset
, int length
)
530 if (value
== NULL
|| !value
->optimized_out
)
532 if (value
->lval
!= lval_computed
533 || !value
->location
.computed
.funcs
->check_validity
)
535 return value
->location
.computed
.funcs
->check_validity (value
, offset
,
540 value_embedded_offset (struct value
*value
)
542 return value
->embedded_offset
;
546 set_value_embedded_offset (struct value
*value
, int val
)
548 value
->embedded_offset
= val
;
552 value_pointed_to_offset (struct value
*value
)
554 return value
->pointed_to_offset
;
558 set_value_pointed_to_offset (struct value
*value
, int val
)
560 value
->pointed_to_offset
= val
;
564 value_computed_funcs (struct value
*v
)
566 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
568 return v
->location
.computed
.funcs
;
572 value_computed_closure (const struct value
*v
)
574 gdb_assert (v
->lval
== lval_computed
);
576 return v
->location
.computed
.closure
;
580 deprecated_value_lval_hack (struct value
*value
)
586 value_address (struct value
*value
)
588 if (value
->lval
== lval_internalvar
589 || value
->lval
== lval_internalvar_component
)
591 return value
->location
.address
+ value
->offset
;
595 value_raw_address (struct value
*value
)
597 if (value
->lval
== lval_internalvar
598 || value
->lval
== lval_internalvar_component
)
600 return value
->location
.address
;
604 set_value_address (struct value
*value
, CORE_ADDR addr
)
606 gdb_assert (value
->lval
!= lval_internalvar
607 && value
->lval
!= lval_internalvar_component
);
608 value
->location
.address
= addr
;
611 struct internalvar
**
612 deprecated_value_internalvar_hack (struct value
*value
)
614 return &value
->location
.internalvar
;
618 deprecated_value_frame_id_hack (struct value
*value
)
620 return &value
->frame_id
;
624 deprecated_value_regnum_hack (struct value
*value
)
626 return &value
->regnum
;
630 deprecated_value_modifiable (struct value
*value
)
632 return value
->modifiable
;
635 deprecated_set_value_modifiable (struct value
*value
, int modifiable
)
637 value
->modifiable
= modifiable
;
640 /* Return a mark in the value chain. All values allocated after the
641 mark is obtained (except for those released) are subject to being freed
642 if a subsequent value_free_to_mark is passed the mark. */
649 /* Take a reference to VAL. VAL will not be deallocated until all
650 references are released. */
653 value_incref (struct value
*val
)
655 val
->reference_count
++;
658 /* Release a reference to VAL, which was acquired with value_incref.
659 This function is also called to deallocate values from the value
663 value_free (struct value
*val
)
667 gdb_assert (val
->reference_count
> 0);
668 val
->reference_count
--;
669 if (val
->reference_count
> 0)
672 /* If there's an associated parent value, drop our reference to
674 if (val
->parent
!= NULL
)
675 value_free (val
->parent
);
677 if (VALUE_LVAL (val
) == lval_computed
)
679 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
681 if (funcs
->free_closure
)
682 funcs
->free_closure (val
);
685 xfree (val
->contents
);
690 /* Free all values allocated since MARK was obtained by value_mark
691 (except for those released). */
693 value_free_to_mark (struct value
*mark
)
698 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
706 /* Free all the values that have been allocated (except for those released).
707 Call after each command, successful or not.
708 In practice this is called before each command, which is sufficient. */
711 free_all_values (void)
716 for (val
= all_values
; val
; val
= next
)
725 /* Frees all the elements in a chain of values. */
728 free_value_chain (struct value
*v
)
734 next
= value_next (v
);
739 /* Remove VAL from the chain all_values
740 so it will not be freed automatically. */
743 release_value (struct value
*val
)
747 if (all_values
== val
)
749 all_values
= val
->next
;
753 for (v
= all_values
; v
; v
= v
->next
)
763 /* Release all values up to mark */
765 value_release_to_mark (struct value
*mark
)
770 for (val
= next
= all_values
; next
; next
= next
->next
)
771 if (next
->next
== mark
)
773 all_values
= next
->next
;
781 /* Return a copy of the value ARG.
782 It contains the same contents, for same memory address,
783 but it's a different block of storage. */
786 value_copy (struct value
*arg
)
788 struct type
*encl_type
= value_enclosing_type (arg
);
791 if (value_lazy (arg
))
792 val
= allocate_value_lazy (encl_type
);
794 val
= allocate_value (encl_type
);
795 val
->type
= arg
->type
;
796 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
797 val
->location
= arg
->location
;
798 val
->offset
= arg
->offset
;
799 val
->bitpos
= arg
->bitpos
;
800 val
->bitsize
= arg
->bitsize
;
801 VALUE_FRAME_ID (val
) = VALUE_FRAME_ID (arg
);
802 VALUE_REGNUM (val
) = VALUE_REGNUM (arg
);
803 val
->lazy
= arg
->lazy
;
804 val
->optimized_out
= arg
->optimized_out
;
805 val
->embedded_offset
= value_embedded_offset (arg
);
806 val
->pointed_to_offset
= arg
->pointed_to_offset
;
807 val
->modifiable
= arg
->modifiable
;
808 if (!value_lazy (val
))
810 memcpy (value_contents_all_raw (val
), value_contents_all_raw (arg
),
811 TYPE_LENGTH (value_enclosing_type (arg
)));
814 val
->parent
= arg
->parent
;
816 value_incref (val
->parent
);
817 if (VALUE_LVAL (val
) == lval_computed
)
819 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
821 if (funcs
->copy_closure
)
822 val
->location
.computed
.closure
= funcs
->copy_closure (val
);
828 set_value_component_location (struct value
*component
,
829 const struct value
*whole
)
831 if (whole
->lval
== lval_internalvar
)
832 VALUE_LVAL (component
) = lval_internalvar_component
;
834 VALUE_LVAL (component
) = whole
->lval
;
836 component
->location
= whole
->location
;
837 if (whole
->lval
== lval_computed
)
839 struct lval_funcs
*funcs
= whole
->location
.computed
.funcs
;
841 if (funcs
->copy_closure
)
842 component
->location
.computed
.closure
= funcs
->copy_closure (whole
);
847 /* Access to the value history. */
849 /* Record a new value in the value history.
850 Returns the absolute history index of the entry.
851 Result of -1 indicates the value was not saved; otherwise it is the
852 value history index of this new item. */
855 record_latest_value (struct value
*val
)
859 /* We don't want this value to have anything to do with the inferior anymore.
860 In particular, "set $1 = 50" should not affect the variable from which
861 the value was taken, and fast watchpoints should be able to assume that
862 a value on the value history never changes. */
863 if (value_lazy (val
))
864 value_fetch_lazy (val
);
865 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
866 from. This is a bit dubious, because then *&$1 does not just return $1
867 but the current contents of that location. c'est la vie... */
871 /* Here we treat value_history_count as origin-zero
872 and applying to the value being stored now. */
874 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
877 struct value_history_chunk
*new
878 = (struct value_history_chunk
*)
880 xmalloc (sizeof (struct value_history_chunk
));
881 memset (new->values
, 0, sizeof new->values
);
882 new->next
= value_history_chain
;
883 value_history_chain
= new;
886 value_history_chain
->values
[i
] = val
;
888 /* Now we regard value_history_count as origin-one
889 and applying to the value just stored. */
891 return ++value_history_count
;
894 /* Return a copy of the value in the history with sequence number NUM. */
897 access_value_history (int num
)
899 struct value_history_chunk
*chunk
;
904 absnum
+= value_history_count
;
909 error (_("The history is empty."));
911 error (_("There is only one value in the history."));
913 error (_("History does not go back to $$%d."), -num
);
915 if (absnum
> value_history_count
)
916 error (_("History has not yet reached $%d."), absnum
);
920 /* Now absnum is always absolute and origin zero. */
922 chunk
= value_history_chain
;
923 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
927 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
931 show_values (char *num_exp
, int from_tty
)
939 /* "show values +" should print from the stored position.
940 "show values <exp>" should print around value number <exp>. */
941 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
942 num
= parse_and_eval_long (num_exp
) - 5;
946 /* "show values" means print the last 10 values. */
947 num
= value_history_count
- 9;
953 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
955 struct value_print_options opts
;
957 val
= access_value_history (i
);
958 printf_filtered (("$%d = "), i
);
959 get_user_print_options (&opts
);
960 value_print (val
, gdb_stdout
, &opts
);
961 printf_filtered (("\n"));
964 /* The next "show values +" should start after what we just printed. */
967 /* Hitting just return after this command should do the same thing as
968 "show values +". If num_exp is null, this is unnecessary, since
969 "show values +" is not useful after "show values". */
970 if (from_tty
&& num_exp
)
977 /* Internal variables. These are variables within the debugger
978 that hold values assigned by debugger commands.
979 The user refers to them with a '$' prefix
980 that does not appear in the variable names stored internally. */
984 struct internalvar
*next
;
987 /* We support various different kinds of content of an internal variable.
988 enum internalvar_kind specifies the kind, and union internalvar_data
989 provides the data associated with this particular kind. */
991 enum internalvar_kind
993 /* The internal variable is empty. */
996 /* The value of the internal variable is provided directly as
997 a GDB value object. */
1000 /* A fresh value is computed via a call-back routine on every
1001 access to the internal variable. */
1002 INTERNALVAR_MAKE_VALUE
,
1004 /* The internal variable holds a GDB internal convenience function. */
1005 INTERNALVAR_FUNCTION
,
1007 /* The variable holds an integer value. */
1008 INTERNALVAR_INTEGER
,
1010 /* The variable holds a pointer value. */
1011 INTERNALVAR_POINTER
,
1013 /* The variable holds a GDB-provided string. */
1018 union internalvar_data
1020 /* A value object used with INTERNALVAR_VALUE. */
1021 struct value
*value
;
1023 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
1024 internalvar_make_value make_value
;
1026 /* The internal function used with INTERNALVAR_FUNCTION. */
1029 struct internal_function
*function
;
1030 /* True if this is the canonical name for the function. */
1034 /* An integer value used with INTERNALVAR_INTEGER. */
1037 /* If type is non-NULL, it will be used as the type to generate
1038 a value for this internal variable. If type is NULL, a default
1039 integer type for the architecture is used. */
1044 /* A pointer value used with INTERNALVAR_POINTER. */
1051 /* A string value used with INTERNALVAR_STRING. */
1056 static struct internalvar
*internalvars
;
1058 /* If the variable does not already exist create it and give it the value given.
1059 If no value is given then the default is zero. */
1061 init_if_undefined_command (char* args
, int from_tty
)
1063 struct internalvar
* intvar
;
1065 /* Parse the expression - this is taken from set_command(). */
1066 struct expression
*expr
= parse_expression (args
);
1067 register struct cleanup
*old_chain
=
1068 make_cleanup (free_current_contents
, &expr
);
1070 /* Validate the expression.
1071 Was the expression an assignment?
1072 Or even an expression at all? */
1073 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
1074 error (_("Init-if-undefined requires an assignment expression."));
1076 /* Extract the variable from the parsed expression.
1077 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
1078 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
1079 error (_("The first parameter to init-if-undefined should be a GDB variable."));
1080 intvar
= expr
->elts
[2].internalvar
;
1082 /* Only evaluate the expression if the lvalue is void.
1083 This may still fail if the expresssion is invalid. */
1084 if (intvar
->kind
== INTERNALVAR_VOID
)
1085 evaluate_expression (expr
);
1087 do_cleanups (old_chain
);
1091 /* Look up an internal variable with name NAME. NAME should not
1092 normally include a dollar sign.
1094 If the specified internal variable does not exist,
1095 the return value is NULL. */
1097 struct internalvar
*
1098 lookup_only_internalvar (const char *name
)
1100 struct internalvar
*var
;
1102 for (var
= internalvars
; var
; var
= var
->next
)
1103 if (strcmp (var
->name
, name
) == 0)
1110 /* Create an internal variable with name NAME and with a void value.
1111 NAME should not normally include a dollar sign. */
1113 struct internalvar
*
1114 create_internalvar (const char *name
)
1116 struct internalvar
*var
;
1118 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
1119 var
->name
= concat (name
, (char *)NULL
);
1120 var
->kind
= INTERNALVAR_VOID
;
1121 var
->next
= internalvars
;
1126 /* Create an internal variable with name NAME and register FUN as the
1127 function that value_of_internalvar uses to create a value whenever
1128 this variable is referenced. NAME should not normally include a
1131 struct internalvar
*
1132 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
1134 struct internalvar
*var
= create_internalvar (name
);
1136 var
->kind
= INTERNALVAR_MAKE_VALUE
;
1137 var
->u
.make_value
= fun
;
1141 /* Look up an internal variable with name NAME. NAME should not
1142 normally include a dollar sign.
1144 If the specified internal variable does not exist,
1145 one is created, with a void value. */
1147 struct internalvar
*
1148 lookup_internalvar (const char *name
)
1150 struct internalvar
*var
;
1152 var
= lookup_only_internalvar (name
);
1156 return create_internalvar (name
);
1159 /* Return current value of internal variable VAR. For variables that
1160 are not inherently typed, use a value type appropriate for GDBARCH. */
1163 value_of_internalvar (struct gdbarch
*gdbarch
, struct internalvar
*var
)
1169 case INTERNALVAR_VOID
:
1170 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1173 case INTERNALVAR_FUNCTION
:
1174 val
= allocate_value (builtin_type (gdbarch
)->internal_fn
);
1177 case INTERNALVAR_INTEGER
:
1178 if (!var
->u
.integer
.type
)
1179 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
1180 var
->u
.integer
.val
);
1182 val
= value_from_longest (var
->u
.integer
.type
, var
->u
.integer
.val
);
1185 case INTERNALVAR_POINTER
:
1186 val
= value_from_pointer (var
->u
.pointer
.type
, var
->u
.pointer
.val
);
1189 case INTERNALVAR_STRING
:
1190 val
= value_cstring (var
->u
.string
, strlen (var
->u
.string
),
1191 builtin_type (gdbarch
)->builtin_char
);
1194 case INTERNALVAR_VALUE
:
1195 val
= value_copy (var
->u
.value
);
1196 if (value_lazy (val
))
1197 value_fetch_lazy (val
);
1200 case INTERNALVAR_MAKE_VALUE
:
1201 val
= (*var
->u
.make_value
) (gdbarch
, var
);
1205 internal_error (__FILE__
, __LINE__
, "bad kind");
1208 /* Change the VALUE_LVAL to lval_internalvar so that future operations
1209 on this value go back to affect the original internal variable.
1211 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
1212 no underlying modifyable state in the internal variable.
1214 Likewise, if the variable's value is a computed lvalue, we want
1215 references to it to produce another computed lvalue, where
1216 references and assignments actually operate through the
1217 computed value's functions.
1219 This means that internal variables with computed values
1220 behave a little differently from other internal variables:
1221 assignments to them don't just replace the previous value
1222 altogether. At the moment, this seems like the behavior we
1225 if (var
->kind
!= INTERNALVAR_MAKE_VALUE
1226 && val
->lval
!= lval_computed
)
1228 VALUE_LVAL (val
) = lval_internalvar
;
1229 VALUE_INTERNALVAR (val
) = var
;
1236 get_internalvar_integer (struct internalvar
*var
, LONGEST
*result
)
1240 case INTERNALVAR_INTEGER
:
1241 *result
= var
->u
.integer
.val
;
1250 get_internalvar_function (struct internalvar
*var
,
1251 struct internal_function
**result
)
1255 case INTERNALVAR_FUNCTION
:
1256 *result
= var
->u
.fn
.function
;
1265 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1266 int bitsize
, struct value
*newval
)
1272 case INTERNALVAR_VALUE
:
1273 addr
= value_contents_writeable (var
->u
.value
);
1276 modify_field (value_type (var
->u
.value
), addr
+ offset
,
1277 value_as_long (newval
), bitpos
, bitsize
);
1279 memcpy (addr
+ offset
, value_contents (newval
),
1280 TYPE_LENGTH (value_type (newval
)));
1284 /* We can never get a component of any other kind. */
1285 internal_error (__FILE__
, __LINE__
, "set_internalvar_component");
1290 set_internalvar (struct internalvar
*var
, struct value
*val
)
1292 enum internalvar_kind new_kind
;
1293 union internalvar_data new_data
= { 0 };
1295 if (var
->kind
== INTERNALVAR_FUNCTION
&& var
->u
.fn
.canonical
)
1296 error (_("Cannot overwrite convenience function %s"), var
->name
);
1298 /* Prepare new contents. */
1299 switch (TYPE_CODE (check_typedef (value_type (val
))))
1301 case TYPE_CODE_VOID
:
1302 new_kind
= INTERNALVAR_VOID
;
1305 case TYPE_CODE_INTERNAL_FUNCTION
:
1306 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1307 new_kind
= INTERNALVAR_FUNCTION
;
1308 get_internalvar_function (VALUE_INTERNALVAR (val
),
1309 &new_data
.fn
.function
);
1310 /* Copies created here are never canonical. */
1314 new_kind
= INTERNALVAR_INTEGER
;
1315 new_data
.integer
.type
= value_type (val
);
1316 new_data
.integer
.val
= value_as_long (val
);
1320 new_kind
= INTERNALVAR_POINTER
;
1321 new_data
.pointer
.type
= value_type (val
);
1322 new_data
.pointer
.val
= value_as_address (val
);
1326 new_kind
= INTERNALVAR_VALUE
;
1327 new_data
.value
= value_copy (val
);
1328 new_data
.value
->modifiable
= 1;
1330 /* Force the value to be fetched from the target now, to avoid problems
1331 later when this internalvar is referenced and the target is gone or
1333 if (value_lazy (new_data
.value
))
1334 value_fetch_lazy (new_data
.value
);
1336 /* Release the value from the value chain to prevent it from being
1337 deleted by free_all_values. From here on this function should not
1338 call error () until new_data is installed into the var->u to avoid
1340 release_value (new_data
.value
);
1344 /* Clean up old contents. */
1345 clear_internalvar (var
);
1348 var
->kind
= new_kind
;
1350 /* End code which must not call error(). */
1354 set_internalvar_integer (struct internalvar
*var
, LONGEST l
)
1356 /* Clean up old contents. */
1357 clear_internalvar (var
);
1359 var
->kind
= INTERNALVAR_INTEGER
;
1360 var
->u
.integer
.type
= NULL
;
1361 var
->u
.integer
.val
= l
;
1365 set_internalvar_string (struct internalvar
*var
, const char *string
)
1367 /* Clean up old contents. */
1368 clear_internalvar (var
);
1370 var
->kind
= INTERNALVAR_STRING
;
1371 var
->u
.string
= xstrdup (string
);
1375 set_internalvar_function (struct internalvar
*var
, struct internal_function
*f
)
1377 /* Clean up old contents. */
1378 clear_internalvar (var
);
1380 var
->kind
= INTERNALVAR_FUNCTION
;
1381 var
->u
.fn
.function
= f
;
1382 var
->u
.fn
.canonical
= 1;
1383 /* Variables installed here are always the canonical version. */
1387 clear_internalvar (struct internalvar
*var
)
1389 /* Clean up old contents. */
1392 case INTERNALVAR_VALUE
:
1393 value_free (var
->u
.value
);
1396 case INTERNALVAR_STRING
:
1397 xfree (var
->u
.string
);
1404 /* Reset to void kind. */
1405 var
->kind
= INTERNALVAR_VOID
;
1409 internalvar_name (struct internalvar
*var
)
1414 static struct internal_function
*
1415 create_internal_function (const char *name
,
1416 internal_function_fn handler
, void *cookie
)
1418 struct internal_function
*ifn
= XNEW (struct internal_function
);
1420 ifn
->name
= xstrdup (name
);
1421 ifn
->handler
= handler
;
1422 ifn
->cookie
= cookie
;
1427 value_internal_function_name (struct value
*val
)
1429 struct internal_function
*ifn
;
1432 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1433 result
= get_internalvar_function (VALUE_INTERNALVAR (val
), &ifn
);
1434 gdb_assert (result
);
1440 call_internal_function (struct gdbarch
*gdbarch
,
1441 const struct language_defn
*language
,
1442 struct value
*func
, int argc
, struct value
**argv
)
1444 struct internal_function
*ifn
;
1447 gdb_assert (VALUE_LVAL (func
) == lval_internalvar
);
1448 result
= get_internalvar_function (VALUE_INTERNALVAR (func
), &ifn
);
1449 gdb_assert (result
);
1451 return (*ifn
->handler
) (gdbarch
, language
, ifn
->cookie
, argc
, argv
);
1454 /* The 'function' command. This does nothing -- it is just a
1455 placeholder to let "help function NAME" work. This is also used as
1456 the implementation of the sub-command that is created when
1457 registering an internal function. */
1459 function_command (char *command
, int from_tty
)
1464 /* Clean up if an internal function's command is destroyed. */
1466 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1472 /* Add a new internal function. NAME is the name of the function; DOC
1473 is a documentation string describing the function. HANDLER is
1474 called when the function is invoked. COOKIE is an arbitrary
1475 pointer which is passed to HANDLER and is intended for "user
1478 add_internal_function (const char *name
, const char *doc
,
1479 internal_function_fn handler
, void *cookie
)
1481 struct cmd_list_element
*cmd
;
1482 struct internal_function
*ifn
;
1483 struct internalvar
*var
= lookup_internalvar (name
);
1485 ifn
= create_internal_function (name
, handler
, cookie
);
1486 set_internalvar_function (var
, ifn
);
1488 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1490 cmd
->destroyer
= function_destroyer
;
1493 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1494 prevent cycles / duplicates. */
1497 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1498 htab_t copied_types
)
1500 if (TYPE_OBJFILE (value
->type
) == objfile
)
1501 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1503 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1504 value
->enclosing_type
= copy_type_recursive (objfile
,
1505 value
->enclosing_type
,
1509 /* Likewise for internal variable VAR. */
1512 preserve_one_internalvar (struct internalvar
*var
, struct objfile
*objfile
,
1513 htab_t copied_types
)
1517 case INTERNALVAR_INTEGER
:
1518 if (var
->u
.integer
.type
&& TYPE_OBJFILE (var
->u
.integer
.type
) == objfile
)
1520 = copy_type_recursive (objfile
, var
->u
.integer
.type
, copied_types
);
1523 case INTERNALVAR_POINTER
:
1524 if (TYPE_OBJFILE (var
->u
.pointer
.type
) == objfile
)
1526 = copy_type_recursive (objfile
, var
->u
.pointer
.type
, copied_types
);
1529 case INTERNALVAR_VALUE
:
1530 preserve_one_value (var
->u
.value
, objfile
, copied_types
);
1535 /* Update the internal variables and value history when OBJFILE is
1536 discarded; we must copy the types out of the objfile. New global types
1537 will be created for every convenience variable which currently points to
1538 this objfile's types, and the convenience variables will be adjusted to
1539 use the new global types. */
1542 preserve_values (struct objfile
*objfile
)
1544 htab_t copied_types
;
1545 struct value_history_chunk
*cur
;
1546 struct internalvar
*var
;
1549 /* Create the hash table. We allocate on the objfile's obstack, since
1550 it is soon to be deleted. */
1551 copied_types
= create_copied_types_hash (objfile
);
1553 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1554 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1556 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1558 for (var
= internalvars
; var
; var
= var
->next
)
1559 preserve_one_internalvar (var
, objfile
, copied_types
);
1561 preserve_python_values (objfile
, copied_types
);
1563 htab_delete (copied_types
);
1567 show_convenience (char *ignore
, int from_tty
)
1569 struct gdbarch
*gdbarch
= get_current_arch ();
1570 struct internalvar
*var
;
1572 struct value_print_options opts
;
1574 get_user_print_options (&opts
);
1575 for (var
= internalvars
; var
; var
= var
->next
)
1581 printf_filtered (("$%s = "), var
->name
);
1582 value_print (value_of_internalvar (gdbarch
, var
), gdb_stdout
,
1584 printf_filtered (("\n"));
1587 printf_unfiltered (_("\
1588 No debugger convenience variables now defined.\n\
1589 Convenience variables have names starting with \"$\";\n\
1590 use \"set\" as in \"set $foo = 5\" to define them.\n"));
1593 /* Extract a value as a C number (either long or double).
1594 Knows how to convert fixed values to double, or
1595 floating values to long.
1596 Does not deallocate the value. */
1599 value_as_long (struct value
*val
)
1601 /* This coerces arrays and functions, which is necessary (e.g.
1602 in disassemble_command). It also dereferences references, which
1603 I suspect is the most logical thing to do. */
1604 val
= coerce_array (val
);
1605 return unpack_long (value_type (val
), value_contents (val
));
1609 value_as_double (struct value
*val
)
1614 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1616 error (_("Invalid floating value found in program."));
1620 /* Extract a value as a C pointer. Does not deallocate the value.
1621 Note that val's type may not actually be a pointer; value_as_long
1622 handles all the cases. */
1624 value_as_address (struct value
*val
)
1626 struct gdbarch
*gdbarch
= get_type_arch (value_type (val
));
1628 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1629 whether we want this to be true eventually. */
1631 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1632 non-address (e.g. argument to "signal", "info break", etc.), or
1633 for pointers to char, in which the low bits *are* significant. */
1634 return gdbarch_addr_bits_remove (gdbarch
, value_as_long (val
));
1637 /* There are several targets (IA-64, PowerPC, and others) which
1638 don't represent pointers to functions as simply the address of
1639 the function's entry point. For example, on the IA-64, a
1640 function pointer points to a two-word descriptor, generated by
1641 the linker, which contains the function's entry point, and the
1642 value the IA-64 "global pointer" register should have --- to
1643 support position-independent code. The linker generates
1644 descriptors only for those functions whose addresses are taken.
1646 On such targets, it's difficult for GDB to convert an arbitrary
1647 function address into a function pointer; it has to either find
1648 an existing descriptor for that function, or call malloc and
1649 build its own. On some targets, it is impossible for GDB to
1650 build a descriptor at all: the descriptor must contain a jump
1651 instruction; data memory cannot be executed; and code memory
1654 Upon entry to this function, if VAL is a value of type `function'
1655 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1656 value_address (val) is the address of the function. This is what
1657 you'll get if you evaluate an expression like `main'. The call
1658 to COERCE_ARRAY below actually does all the usual unary
1659 conversions, which includes converting values of type `function'
1660 to `pointer to function'. This is the challenging conversion
1661 discussed above. Then, `unpack_long' will convert that pointer
1662 back into an address.
1664 So, suppose the user types `disassemble foo' on an architecture
1665 with a strange function pointer representation, on which GDB
1666 cannot build its own descriptors, and suppose further that `foo'
1667 has no linker-built descriptor. The address->pointer conversion
1668 will signal an error and prevent the command from running, even
1669 though the next step would have been to convert the pointer
1670 directly back into the same address.
1672 The following shortcut avoids this whole mess. If VAL is a
1673 function, just return its address directly. */
1674 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
1675 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
1676 return value_address (val
);
1678 val
= coerce_array (val
);
1680 /* Some architectures (e.g. Harvard), map instruction and data
1681 addresses onto a single large unified address space. For
1682 instance: An architecture may consider a large integer in the
1683 range 0x10000000 .. 0x1000ffff to already represent a data
1684 addresses (hence not need a pointer to address conversion) while
1685 a small integer would still need to be converted integer to
1686 pointer to address. Just assume such architectures handle all
1687 integer conversions in a single function. */
1691 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1692 must admonish GDB hackers to make sure its behavior matches the
1693 compiler's, whenever possible.
1695 In general, I think GDB should evaluate expressions the same way
1696 the compiler does. When the user copies an expression out of
1697 their source code and hands it to a `print' command, they should
1698 get the same value the compiler would have computed. Any
1699 deviation from this rule can cause major confusion and annoyance,
1700 and needs to be justified carefully. In other words, GDB doesn't
1701 really have the freedom to do these conversions in clever and
1704 AndrewC pointed out that users aren't complaining about how GDB
1705 casts integers to pointers; they are complaining that they can't
1706 take an address from a disassembly listing and give it to `x/i'.
1707 This is certainly important.
1709 Adding an architecture method like integer_to_address() certainly
1710 makes it possible for GDB to "get it right" in all circumstances
1711 --- the target has complete control over how things get done, so
1712 people can Do The Right Thing for their target without breaking
1713 anyone else. The standard doesn't specify how integers get
1714 converted to pointers; usually, the ABI doesn't either, but
1715 ABI-specific code is a more reasonable place to handle it. */
1717 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
1718 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
1719 && gdbarch_integer_to_address_p (gdbarch
))
1720 return gdbarch_integer_to_address (gdbarch
, value_type (val
),
1721 value_contents (val
));
1723 return unpack_long (value_type (val
), value_contents (val
));
1727 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1728 as a long, or as a double, assuming the raw data is described
1729 by type TYPE. Knows how to convert different sizes of values
1730 and can convert between fixed and floating point. We don't assume
1731 any alignment for the raw data. Return value is in host byte order.
1733 If you want functions and arrays to be coerced to pointers, and
1734 references to be dereferenced, call value_as_long() instead.
1736 C++: It is assumed that the front-end has taken care of
1737 all matters concerning pointers to members. A pointer
1738 to member which reaches here is considered to be equivalent
1739 to an INT (or some size). After all, it is only an offset. */
1742 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
1744 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1745 enum type_code code
= TYPE_CODE (type
);
1746 int len
= TYPE_LENGTH (type
);
1747 int nosign
= TYPE_UNSIGNED (type
);
1751 case TYPE_CODE_TYPEDEF
:
1752 return unpack_long (check_typedef (type
), valaddr
);
1753 case TYPE_CODE_ENUM
:
1754 case TYPE_CODE_FLAGS
:
1755 case TYPE_CODE_BOOL
:
1757 case TYPE_CODE_CHAR
:
1758 case TYPE_CODE_RANGE
:
1759 case TYPE_CODE_MEMBERPTR
:
1761 return extract_unsigned_integer (valaddr
, len
, byte_order
);
1763 return extract_signed_integer (valaddr
, len
, byte_order
);
1766 return extract_typed_floating (valaddr
, type
);
1768 case TYPE_CODE_DECFLOAT
:
1769 /* libdecnumber has a function to convert from decimal to integer, but
1770 it doesn't work when the decimal number has a fractional part. */
1771 return decimal_to_doublest (valaddr
, len
, byte_order
);
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 extract_typed_address (valaddr
, type
);
1780 error (_("Value can't be converted to integer."));
1782 return 0; /* Placate lint. */
1785 /* Return a double value from the specified type and address.
1786 INVP points to an int which is set to 0 for valid value,
1787 1 for invalid value (bad float format). In either case,
1788 the returned double is OK to use. Argument is in target
1789 format, result is in host format. */
1792 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
1794 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1795 enum type_code code
;
1799 *invp
= 0; /* Assume valid. */
1800 CHECK_TYPEDEF (type
);
1801 code
= TYPE_CODE (type
);
1802 len
= TYPE_LENGTH (type
);
1803 nosign
= TYPE_UNSIGNED (type
);
1804 if (code
== TYPE_CODE_FLT
)
1806 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1807 floating-point value was valid (using the macro
1808 INVALID_FLOAT). That test/macro have been removed.
1810 It turns out that only the VAX defined this macro and then
1811 only in a non-portable way. Fixing the portability problem
1812 wouldn't help since the VAX floating-point code is also badly
1813 bit-rotten. The target needs to add definitions for the
1814 methods gdbarch_float_format and gdbarch_double_format - these
1815 exactly describe the target floating-point format. The
1816 problem here is that the corresponding floatformat_vax_f and
1817 floatformat_vax_d values these methods should be set to are
1818 also not defined either. Oops!
1820 Hopefully someone will add both the missing floatformat
1821 definitions and the new cases for floatformat_is_valid (). */
1823 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
1829 return extract_typed_floating (valaddr
, type
);
1831 else if (code
== TYPE_CODE_DECFLOAT
)
1832 return decimal_to_doublest (valaddr
, len
, byte_order
);
1835 /* Unsigned -- be sure we compensate for signed LONGEST. */
1836 return (ULONGEST
) unpack_long (type
, valaddr
);
1840 /* Signed -- we are OK with unpack_long. */
1841 return unpack_long (type
, valaddr
);
1845 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1846 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1847 We don't assume any alignment for the raw data. Return value is in
1850 If you want functions and arrays to be coerced to pointers, and
1851 references to be dereferenced, call value_as_address() instead.
1853 C++: It is assumed that the front-end has taken care of
1854 all matters concerning pointers to members. A pointer
1855 to member which reaches here is considered to be equivalent
1856 to an INT (or some size). After all, it is only an offset. */
1859 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
1861 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1862 whether we want this to be true eventually. */
1863 return unpack_long (type
, valaddr
);
1867 /* Get the value of the FIELDNO'th field (which must be static) of
1868 TYPE. Return NULL if the field doesn't exist or has been
1872 value_static_field (struct type
*type
, int fieldno
)
1874 struct value
*retval
;
1876 switch (TYPE_FIELD_LOC_KIND (type
, fieldno
))
1878 case FIELD_LOC_KIND_PHYSADDR
:
1879 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
1880 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1882 case FIELD_LOC_KIND_PHYSNAME
:
1884 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1885 /*TYPE_FIELD_NAME (type, fieldno);*/
1886 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1890 /* With some compilers, e.g. HP aCC, static data members are
1891 reported as non-debuggable symbols */
1892 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
,
1899 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
1900 SYMBOL_VALUE_ADDRESS (msym
));
1905 /* SYM should never have a SYMBOL_CLASS which will require
1906 read_var_value to use the FRAME parameter. */
1907 if (symbol_read_needs_frame (sym
))
1908 warning (_("static field's value depends on the current "
1909 "frame - bad debug info?"));
1910 retval
= read_var_value (sym
, NULL
);
1912 if (retval
&& VALUE_LVAL (retval
) == lval_memory
)
1913 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
),
1914 value_address (retval
));
1924 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1925 You have to be careful here, since the size of the data area for the value
1926 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1927 than the old enclosing type, you have to allocate more space for the data.
1928 The return value is a pointer to the new version of this value structure. */
1931 value_change_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
1933 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
1935 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
1937 val
->enclosing_type
= new_encl_type
;
1941 /* Given a value ARG1 (offset by OFFSET bytes)
1942 of a struct or union type ARG_TYPE,
1943 extract and return the value of one of its (non-static) fields.
1944 FIELDNO says which field. */
1947 value_primitive_field (struct value
*arg1
, int offset
,
1948 int fieldno
, struct type
*arg_type
)
1953 CHECK_TYPEDEF (arg_type
);
1954 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
1956 /* Call check_typedef on our type to make sure that, if TYPE
1957 is a TYPE_CODE_TYPEDEF, its length is set to the length
1958 of the target type instead of zero. However, we do not
1959 replace the typedef type by the target type, because we want
1960 to keep the typedef in order to be able to print the type
1961 description correctly. */
1962 check_typedef (type
);
1964 /* Handle packed fields */
1966 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
1968 /* Create a new value for the bitfield, with bitpos and bitsize
1969 set. If possible, arrange offset and bitpos so that we can
1970 do a single aligned read of the size of the containing type.
1971 Otherwise, adjust offset to the byte containing the first
1972 bit. Assume that the address, offset, and embedded offset
1973 are sufficiently aligned. */
1974 int bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
);
1975 int container_bitsize
= TYPE_LENGTH (type
) * 8;
1977 v
= allocate_value_lazy (type
);
1978 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
1979 if ((bitpos
% container_bitsize
) + v
->bitsize
<= container_bitsize
1980 && TYPE_LENGTH (type
) <= (int) sizeof (LONGEST
))
1981 v
->bitpos
= bitpos
% container_bitsize
;
1983 v
->bitpos
= bitpos
% 8;
1984 v
->offset
= value_embedded_offset (arg1
)
1985 + (bitpos
- v
->bitpos
) / 8;
1987 value_incref (v
->parent
);
1988 if (!value_lazy (arg1
))
1989 value_fetch_lazy (v
);
1991 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
1993 /* This field is actually a base subobject, so preserve the
1994 entire object's contents for later references to virtual
1997 /* Lazy register values with offsets are not supported. */
1998 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1999 value_fetch_lazy (arg1
);
2001 if (value_lazy (arg1
))
2002 v
= allocate_value_lazy (value_enclosing_type (arg1
));
2005 v
= allocate_value (value_enclosing_type (arg1
));
2006 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
2007 TYPE_LENGTH (value_enclosing_type (arg1
)));
2010 v
->offset
= value_offset (arg1
);
2011 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
2012 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
2016 /* Plain old data member */
2017 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
2019 /* Lazy register values with offsets are not supported. */
2020 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
2021 value_fetch_lazy (arg1
);
2023 if (value_lazy (arg1
))
2024 v
= allocate_value_lazy (type
);
2027 v
= allocate_value (type
);
2028 memcpy (value_contents_raw (v
),
2029 value_contents_raw (arg1
) + offset
,
2030 TYPE_LENGTH (type
));
2032 v
->offset
= (value_offset (arg1
) + offset
2033 + value_embedded_offset (arg1
));
2035 set_value_component_location (v
, arg1
);
2036 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
2037 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
2041 /* Given a value ARG1 of a struct or union type,
2042 extract and return the value of one of its (non-static) fields.
2043 FIELDNO says which field. */
2046 value_field (struct value
*arg1
, int fieldno
)
2048 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
2051 /* Return a non-virtual function as a value.
2052 F is the list of member functions which contains the desired method.
2053 J is an index into F which provides the desired method.
2055 We only use the symbol for its address, so be happy with either a
2056 full symbol or a minimal symbol.
2060 value_fn_field (struct value
**arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
2064 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
2065 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
2067 struct minimal_symbol
*msym
;
2069 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
2076 gdb_assert (sym
== NULL
);
2077 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
2082 v
= allocate_value (ftype
);
2085 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
2089 /* The minimal symbol might point to a function descriptor;
2090 resolve it to the actual code address instead. */
2091 struct objfile
*objfile
= msymbol_objfile (msym
);
2092 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
2094 set_value_address (v
,
2095 gdbarch_convert_from_func_ptr_addr
2096 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
2101 if (type
!= value_type (*arg1p
))
2102 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
2103 value_addr (*arg1p
)));
2105 /* Move the `this' pointer according to the offset.
2106 VALUE_OFFSET (*arg1p) += offset;
2114 /* Unpack a bitfield of the specified FIELD_TYPE, from the anonymous
2115 object at VALADDR. The bitfield starts at BITPOS bits and contains
2118 Extracting bits depends on endianness of the machine. Compute the
2119 number of least significant bits to discard. For big endian machines,
2120 we compute the total number of bits in the anonymous object, subtract
2121 off the bit count from the MSB of the object to the MSB of the
2122 bitfield, then the size of the bitfield, which leaves the LSB discard
2123 count. For little endian machines, the discard count is simply the
2124 number of bits from the LSB of the anonymous object to the LSB of the
2127 If the field is signed, we also do sign extension. */
2130 unpack_bits_as_long (struct type
*field_type
, const gdb_byte
*valaddr
,
2131 int bitpos
, int bitsize
)
2133 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (field_type
));
2139 /* Read the minimum number of bytes required; there may not be
2140 enough bytes to read an entire ULONGEST. */
2141 CHECK_TYPEDEF (field_type
);
2143 bytes_read
= ((bitpos
% 8) + bitsize
+ 7) / 8;
2145 bytes_read
= TYPE_LENGTH (field_type
);
2147 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8,
2148 bytes_read
, byte_order
);
2150 /* Extract bits. See comment above. */
2152 if (gdbarch_bits_big_endian (get_type_arch (field_type
)))
2153 lsbcount
= (bytes_read
* 8 - bitpos
% 8 - bitsize
);
2155 lsbcount
= (bitpos
% 8);
2158 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
2159 If the field is signed, and is negative, then sign extend. */
2161 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
2163 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
2165 if (!TYPE_UNSIGNED (field_type
))
2167 if (val
& (valmask
^ (valmask
>> 1)))
2176 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
2177 VALADDR. See unpack_bits_as_long for more details. */
2180 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
2182 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
2183 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
2184 struct type
*field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
2186 return unpack_bits_as_long (field_type
, valaddr
, bitpos
, bitsize
);
2189 /* Modify the value of a bitfield. ADDR points to a block of memory in
2190 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
2191 is the desired value of the field, in host byte order. BITPOS and BITSIZE
2192 indicate which bits (in target bit order) comprise the bitfield.
2193 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS+BITSIZE <= lbits, and
2194 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
2197 modify_field (struct type
*type
, gdb_byte
*addr
,
2198 LONGEST fieldval
, int bitpos
, int bitsize
)
2200 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2202 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
2204 /* If a negative fieldval fits in the field in question, chop
2205 off the sign extension bits. */
2206 if ((~fieldval
& ~(mask
>> 1)) == 0)
2209 /* Warn if value is too big to fit in the field in question. */
2210 if (0 != (fieldval
& ~mask
))
2212 /* FIXME: would like to include fieldval in the message, but
2213 we don't have a sprintf_longest. */
2214 warning (_("Value does not fit in %d bits."), bitsize
);
2216 /* Truncate it, otherwise adjoining fields may be corrupted. */
2220 oword
= extract_unsigned_integer (addr
, sizeof oword
, byte_order
);
2222 /* Shifting for bit field depends on endianness of the target machine. */
2223 if (gdbarch_bits_big_endian (get_type_arch (type
)))
2224 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
2226 oword
&= ~(mask
<< bitpos
);
2227 oword
|= fieldval
<< bitpos
;
2229 store_unsigned_integer (addr
, sizeof oword
, byte_order
, oword
);
2232 /* Pack NUM into BUF using a target format of TYPE. */
2235 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
2237 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2240 type
= check_typedef (type
);
2241 len
= TYPE_LENGTH (type
);
2243 switch (TYPE_CODE (type
))
2246 case TYPE_CODE_CHAR
:
2247 case TYPE_CODE_ENUM
:
2248 case TYPE_CODE_FLAGS
:
2249 case TYPE_CODE_BOOL
:
2250 case TYPE_CODE_RANGE
:
2251 case TYPE_CODE_MEMBERPTR
:
2252 store_signed_integer (buf
, len
, byte_order
, num
);
2257 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2261 error (_("Unexpected type (%d) encountered for integer constant."),
2267 /* Pack NUM into BUF using a target format of TYPE. */
2270 pack_unsigned_long (gdb_byte
*buf
, struct type
*type
, ULONGEST num
)
2273 enum bfd_endian byte_order
;
2275 type
= check_typedef (type
);
2276 len
= TYPE_LENGTH (type
);
2277 byte_order
= gdbarch_byte_order (get_type_arch (type
));
2279 switch (TYPE_CODE (type
))
2282 case TYPE_CODE_CHAR
:
2283 case TYPE_CODE_ENUM
:
2284 case TYPE_CODE_FLAGS
:
2285 case TYPE_CODE_BOOL
:
2286 case TYPE_CODE_RANGE
:
2287 case TYPE_CODE_MEMBERPTR
:
2288 store_unsigned_integer (buf
, len
, byte_order
, num
);
2293 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2298 Unexpected type (%d) encountered for unsigned integer constant."),
2304 /* Convert C numbers into newly allocated values. */
2307 value_from_longest (struct type
*type
, LONGEST num
)
2309 struct value
*val
= allocate_value (type
);
2311 pack_long (value_contents_raw (val
), type
, num
);
2316 /* Convert C unsigned numbers into newly allocated values. */
2319 value_from_ulongest (struct type
*type
, ULONGEST num
)
2321 struct value
*val
= allocate_value (type
);
2323 pack_unsigned_long (value_contents_raw (val
), type
, num
);
2329 /* Create a value representing a pointer of type TYPE to the address
2332 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
2334 struct value
*val
= allocate_value (type
);
2336 store_typed_address (value_contents_raw (val
), check_typedef (type
), addr
);
2341 /* Create a value of type TYPE whose contents come from VALADDR, if it
2342 is non-null, and whose memory address (in the inferior) is
2346 value_from_contents_and_address (struct type
*type
,
2347 const gdb_byte
*valaddr
,
2350 struct value
*v
= allocate_value (type
);
2352 if (valaddr
== NULL
)
2353 set_value_lazy (v
, 1);
2355 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
2356 set_value_address (v
, address
);
2357 VALUE_LVAL (v
) = lval_memory
;
2362 value_from_double (struct type
*type
, DOUBLEST num
)
2364 struct value
*val
= allocate_value (type
);
2365 struct type
*base_type
= check_typedef (type
);
2366 enum type_code code
= TYPE_CODE (base_type
);
2368 if (code
== TYPE_CODE_FLT
)
2370 store_typed_floating (value_contents_raw (val
), base_type
, num
);
2373 error (_("Unexpected type encountered for floating constant."));
2379 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
2381 struct value
*val
= allocate_value (type
);
2383 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
2388 coerce_ref (struct value
*arg
)
2390 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
2392 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
2393 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
2394 unpack_pointer (value_type (arg
),
2395 value_contents (arg
)));
2400 coerce_array (struct value
*arg
)
2404 arg
= coerce_ref (arg
);
2405 type
= check_typedef (value_type (arg
));
2407 switch (TYPE_CODE (type
))
2409 case TYPE_CODE_ARRAY
:
2410 if (current_language
->c_style_arrays
)
2411 arg
= value_coerce_array (arg
);
2413 case TYPE_CODE_FUNC
:
2414 arg
= value_coerce_function (arg
);
2421 /* Return true if the function returning the specified type is using
2422 the convention of returning structures in memory (passing in the
2423 address as a hidden first parameter). */
2426 using_struct_return (struct gdbarch
*gdbarch
,
2427 struct type
*func_type
, struct type
*value_type
)
2429 enum type_code code
= TYPE_CODE (value_type
);
2431 if (code
== TYPE_CODE_ERROR
)
2432 error (_("Function return type unknown."));
2434 if (code
== TYPE_CODE_VOID
)
2435 /* A void return value is never in memory. See also corresponding
2436 code in "print_return_value". */
2439 /* Probe the architecture for the return-value convention. */
2440 return (gdbarch_return_value (gdbarch
, func_type
, value_type
,
2442 != RETURN_VALUE_REGISTER_CONVENTION
);
2445 /* Set the initialized field in a value struct. */
2448 set_value_initialized (struct value
*val
, int status
)
2450 val
->initialized
= status
;
2453 /* Return the initialized field in a value struct. */
2456 value_initialized (struct value
*val
)
2458 return val
->initialized
;
2462 _initialize_values (void)
2464 add_cmd ("convenience", no_class
, show_convenience
, _("\
2465 Debugger convenience (\"$foo\") variables.\n\
2466 These variables are created when you assign them values;\n\
2467 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2469 A few convenience variables are given values automatically:\n\
2470 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2471 \"$__\" holds the contents of the last address examined with \"x\"."),
2474 add_cmd ("values", no_class
, show_values
,
2475 _("Elements of value history around item number IDX (or last ten)."),
2478 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2479 Initialize a convenience variable if necessary.\n\
2480 init-if-undefined VARIABLE = EXPRESSION\n\
2481 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2482 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2483 VARIABLE is already initialized."));
2485 add_prefix_cmd ("function", no_class
, function_command
, _("\
2486 Placeholder command for showing help on convenience functions."),
2487 &functionlist
, "function ", 0, &cmdlist
);