1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
3 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
4 1996, 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
5 2009, 2010 Free Software Foundation, Inc.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "arch-utils.h"
24 #include "gdb_string.h"
35 #include "gdb_assert.h"
41 #include "cli/cli-decode.h"
43 #include "python/python.h"
45 /* Prototypes for exported functions. */
47 void _initialize_values (void);
49 /* Definition of a user function. */
50 struct internal_function
52 /* The name of the function. It is a bit odd to have this in the
53 function itself -- the user might use a differently-named
54 convenience variable to hold the function. */
58 internal_function_fn handler
;
60 /* User data for the handler. */
64 static struct cmd_list_element
*functionlist
;
68 /* Type of value; either not an lval, or one of the various
69 different possible kinds of lval. */
72 /* Is it modifiable? Only relevant if lval != not_lval. */
75 /* Location of value (if lval). */
78 /* If lval == lval_memory, this is the address in the inferior.
79 If lval == lval_register, this is the byte offset into the
80 registers structure. */
83 /* Pointer to internal variable. */
84 struct internalvar
*internalvar
;
86 /* If lval == lval_computed, this is a set of function pointers
87 to use to access and describe the value, and a closure pointer
91 struct lval_funcs
*funcs
; /* Functions to call. */
92 void *closure
; /* Closure for those functions to use. */
96 /* Describes offset of a value within lval of a structure in bytes.
97 If lval == lval_memory, this is an offset to the address. If
98 lval == lval_register, this is a further offset from
99 location.address within the registers structure. Note also the
100 member embedded_offset below. */
103 /* Only used for bitfields; number of bits contained in them. */
106 /* Only used for bitfields; position of start of field. For
107 gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
108 gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
111 /* Only used for bitfields; the containing value. This allows a
112 single read from the target when displaying multiple
114 struct value
*parent
;
116 /* Frame register value is relative to. This will be described in
117 the lval enum above as "lval_register". */
118 struct frame_id frame_id
;
120 /* Type of the value. */
123 /* If a value represents a C++ object, then the `type' field gives
124 the object's compile-time type. If the object actually belongs
125 to some class derived from `type', perhaps with other base
126 classes and additional members, then `type' is just a subobject
127 of the real thing, and the full object is probably larger than
128 `type' would suggest.
130 If `type' is a dynamic class (i.e. one with a vtable), then GDB
131 can actually determine the object's run-time type by looking at
132 the run-time type information in the vtable. When this
133 information is available, we may elect to read in the entire
134 object, for several reasons:
136 - When printing the value, the user would probably rather see the
137 full object, not just the limited portion apparent from the
140 - If `type' has virtual base classes, then even printing `type'
141 alone may require reaching outside the `type' portion of the
142 object to wherever the virtual base class has been stored.
144 When we store the entire object, `enclosing_type' is the run-time
145 type -- the complete object -- and `embedded_offset' is the
146 offset of `type' within that larger type, in bytes. The
147 value_contents() macro takes `embedded_offset' into account, so
148 most GDB code continues to see the `type' portion of the value,
149 just as the inferior would.
151 If `type' is a pointer to an object, then `enclosing_type' is a
152 pointer to the object's run-time type, and `pointed_to_offset' is
153 the offset in bytes from the full object to the pointed-to object
154 -- that is, the value `embedded_offset' would have if we followed
155 the pointer and fetched the complete object. (I don't really see
156 the point. Why not just determine the run-time type when you
157 indirect, and avoid the special case? The contents don't matter
158 until you indirect anyway.)
160 If we're not doing anything fancy, `enclosing_type' is equal to
161 `type', and `embedded_offset' is zero, so everything works
163 struct type
*enclosing_type
;
165 int pointed_to_offset
;
167 /* Values are stored in a chain, so that they can be deleted easily
168 over calls to the inferior. Values assigned to internal
169 variables, put into the value history or exposed to Python are
170 taken off this list. */
173 /* Register number if the value is from a register. */
176 /* If zero, contents of this value are in the contents field. If
177 nonzero, contents are in inferior. If the lval field is lval_memory,
178 the contents are in inferior memory at location.address plus offset.
179 The lval field may also be lval_register.
181 WARNING: This field is used by the code which handles watchpoints
182 (see breakpoint.c) to decide whether a particular value can be
183 watched by hardware watchpoints. If the lazy flag is set for
184 some member of a value chain, it is assumed that this member of
185 the chain doesn't need to be watched as part of watching the
186 value itself. This is how GDB avoids watching the entire struct
187 or array when the user wants to watch a single struct member or
188 array element. If you ever change the way lazy flag is set and
189 reset, be sure to consider this use as well! */
192 /* If nonzero, this is the value of a variable which does not
193 actually exist in the program. */
196 /* If value is a variable, is it initialized or not. */
199 /* If value is from the stack. If this is set, read_stack will be
200 used instead of read_memory to enable extra caching. */
203 /* Actual contents of the value. Target byte-order. NULL or not
204 valid if lazy is nonzero. */
207 /* The number of references to this value. When a value is created,
208 the value chain holds a reference, so REFERENCE_COUNT is 1. If
209 release_value is called, this value is removed from the chain but
210 the caller of release_value now has a reference to this value.
211 The caller must arrange for a call to value_free later. */
215 /* Prototypes for local functions. */
217 static void show_values (char *, int);
219 static void show_convenience (char *, int);
222 /* The value-history records all the values printed
223 by print commands during this session. Each chunk
224 records 60 consecutive values. The first chunk on
225 the chain records the most recent values.
226 The total number of values is in value_history_count. */
228 #define VALUE_HISTORY_CHUNK 60
230 struct value_history_chunk
232 struct value_history_chunk
*next
;
233 struct value
*values
[VALUE_HISTORY_CHUNK
];
236 /* Chain of chunks now in use. */
238 static struct value_history_chunk
*value_history_chain
;
240 static int value_history_count
; /* Abs number of last entry stored */
243 /* List of all value objects currently allocated
244 (except for those released by calls to release_value)
245 This is so they can be freed after each command. */
247 static struct value
*all_values
;
249 /* Allocate a lazy value for type TYPE. Its actual content is
250 "lazily" allocated too: the content field of the return value is
251 NULL; it will be allocated when it is fetched from the target. */
254 allocate_value_lazy (struct type
*type
)
258 /* Call check_typedef on our type to make sure that, if TYPE
259 is a TYPE_CODE_TYPEDEF, its length is set to the length
260 of the target type instead of zero. However, we do not
261 replace the typedef type by the target type, because we want
262 to keep the typedef in order to be able to set the VAL's type
263 description correctly. */
264 check_typedef (type
);
266 val
= (struct value
*) xzalloc (sizeof (struct value
));
267 val
->contents
= NULL
;
268 val
->next
= all_values
;
271 val
->enclosing_type
= type
;
272 VALUE_LVAL (val
) = not_lval
;
273 val
->location
.address
= 0;
274 VALUE_FRAME_ID (val
) = null_frame_id
;
278 VALUE_REGNUM (val
) = -1;
280 val
->optimized_out
= 0;
281 val
->embedded_offset
= 0;
282 val
->pointed_to_offset
= 0;
284 val
->initialized
= 1; /* Default to initialized. */
286 /* Values start out on the all_values chain. */
287 val
->reference_count
= 1;
292 /* Allocate the contents of VAL if it has not been allocated yet. */
295 allocate_value_contents (struct value
*val
)
298 val
->contents
= (gdb_byte
*) xzalloc (TYPE_LENGTH (val
->enclosing_type
));
301 /* Allocate a value and its contents for type TYPE. */
304 allocate_value (struct type
*type
)
306 struct value
*val
= allocate_value_lazy (type
);
307 allocate_value_contents (val
);
312 /* Allocate a value that has the correct length
313 for COUNT repetitions of type TYPE. */
316 allocate_repeat_value (struct type
*type
, int count
)
318 int low_bound
= current_language
->string_lower_bound
; /* ??? */
319 /* FIXME-type-allocation: need a way to free this type when we are
321 struct type
*array_type
322 = lookup_array_range_type (type
, low_bound
, count
+ low_bound
- 1);
323 return allocate_value (array_type
);
327 allocate_computed_value (struct type
*type
,
328 struct lval_funcs
*funcs
,
331 struct value
*v
= allocate_value (type
);
332 VALUE_LVAL (v
) = lval_computed
;
333 v
->location
.computed
.funcs
= funcs
;
334 v
->location
.computed
.closure
= closure
;
335 set_value_lazy (v
, 1);
340 /* Accessor methods. */
343 value_next (struct value
*value
)
349 value_type (struct value
*value
)
354 deprecated_set_value_type (struct value
*value
, struct type
*type
)
360 value_offset (struct value
*value
)
362 return value
->offset
;
365 set_value_offset (struct value
*value
, int offset
)
367 value
->offset
= offset
;
371 value_bitpos (struct value
*value
)
373 return value
->bitpos
;
376 set_value_bitpos (struct value
*value
, int bit
)
382 value_bitsize (struct value
*value
)
384 return value
->bitsize
;
387 set_value_bitsize (struct value
*value
, int bit
)
389 value
->bitsize
= bit
;
393 value_parent (struct value
*value
)
395 return value
->parent
;
399 value_contents_raw (struct value
*value
)
401 allocate_value_contents (value
);
402 return value
->contents
+ value
->embedded_offset
;
406 value_contents_all_raw (struct value
*value
)
408 allocate_value_contents (value
);
409 return value
->contents
;
413 value_enclosing_type (struct value
*value
)
415 return value
->enclosing_type
;
419 value_contents_all (struct value
*value
)
422 value_fetch_lazy (value
);
423 return value
->contents
;
427 value_lazy (struct value
*value
)
433 set_value_lazy (struct value
*value
, int val
)
439 value_stack (struct value
*value
)
445 set_value_stack (struct value
*value
, int val
)
451 value_contents (struct value
*value
)
453 return value_contents_writeable (value
);
457 value_contents_writeable (struct value
*value
)
460 value_fetch_lazy (value
);
461 return value_contents_raw (value
);
464 /* Return non-zero if VAL1 and VAL2 have the same contents. Note that
465 this function is different from value_equal; in C the operator ==
466 can return 0 even if the two values being compared are equal. */
469 value_contents_equal (struct value
*val1
, struct value
*val2
)
475 type1
= check_typedef (value_type (val1
));
476 type2
= check_typedef (value_type (val2
));
477 len
= TYPE_LENGTH (type1
);
478 if (len
!= TYPE_LENGTH (type2
))
481 return (memcmp (value_contents (val1
), value_contents (val2
), len
) == 0);
485 value_optimized_out (struct value
*value
)
487 return value
->optimized_out
;
491 set_value_optimized_out (struct value
*value
, int val
)
493 value
->optimized_out
= val
;
497 value_embedded_offset (struct value
*value
)
499 return value
->embedded_offset
;
503 set_value_embedded_offset (struct value
*value
, int val
)
505 value
->embedded_offset
= val
;
509 value_pointed_to_offset (struct value
*value
)
511 return value
->pointed_to_offset
;
515 set_value_pointed_to_offset (struct value
*value
, int val
)
517 value
->pointed_to_offset
= val
;
521 value_computed_funcs (struct value
*v
)
523 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
525 return v
->location
.computed
.funcs
;
529 value_computed_closure (struct value
*v
)
531 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
533 return v
->location
.computed
.closure
;
537 deprecated_value_lval_hack (struct value
*value
)
543 value_address (struct value
*value
)
545 if (value
->lval
== lval_internalvar
546 || value
->lval
== lval_internalvar_component
)
548 return value
->location
.address
+ value
->offset
;
552 value_raw_address (struct value
*value
)
554 if (value
->lval
== lval_internalvar
555 || value
->lval
== lval_internalvar_component
)
557 return value
->location
.address
;
561 set_value_address (struct value
*value
, CORE_ADDR addr
)
563 gdb_assert (value
->lval
!= lval_internalvar
564 && value
->lval
!= lval_internalvar_component
);
565 value
->location
.address
= addr
;
568 struct internalvar
**
569 deprecated_value_internalvar_hack (struct value
*value
)
571 return &value
->location
.internalvar
;
575 deprecated_value_frame_id_hack (struct value
*value
)
577 return &value
->frame_id
;
581 deprecated_value_regnum_hack (struct value
*value
)
583 return &value
->regnum
;
587 deprecated_value_modifiable (struct value
*value
)
589 return value
->modifiable
;
592 deprecated_set_value_modifiable (struct value
*value
, int modifiable
)
594 value
->modifiable
= modifiable
;
597 /* Return a mark in the value chain. All values allocated after the
598 mark is obtained (except for those released) are subject to being freed
599 if a subsequent value_free_to_mark is passed the mark. */
606 /* Take a reference to VAL. VAL will not be deallocated until all
607 references are released. */
610 value_incref (struct value
*val
)
612 val
->reference_count
++;
615 /* Release a reference to VAL, which was acquired with value_incref.
616 This function is also called to deallocate values from the value
620 value_free (struct value
*val
)
624 gdb_assert (val
->reference_count
> 0);
625 val
->reference_count
--;
626 if (val
->reference_count
> 0)
629 /* If there's an associated parent value, drop our reference to
631 if (val
->parent
!= NULL
)
632 value_free (val
->parent
);
634 if (VALUE_LVAL (val
) == lval_computed
)
636 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
638 if (funcs
->free_closure
)
639 funcs
->free_closure (val
);
642 xfree (val
->contents
);
647 /* Free all values allocated since MARK was obtained by value_mark
648 (except for those released). */
650 value_free_to_mark (struct value
*mark
)
655 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
663 /* Free all the values that have been allocated (except for those released).
664 Call after each command, successful or not.
665 In practice this is called before each command, which is sufficient. */
668 free_all_values (void)
673 for (val
= all_values
; val
; val
= next
)
682 /* Remove VAL from the chain all_values
683 so it will not be freed automatically. */
686 release_value (struct value
*val
)
690 if (all_values
== val
)
692 all_values
= val
->next
;
696 for (v
= all_values
; v
; v
= v
->next
)
706 /* Release all values up to mark */
708 value_release_to_mark (struct value
*mark
)
713 for (val
= next
= all_values
; next
; next
= next
->next
)
714 if (next
->next
== mark
)
716 all_values
= next
->next
;
724 /* Return a copy of the value ARG.
725 It contains the same contents, for same memory address,
726 but it's a different block of storage. */
729 value_copy (struct value
*arg
)
731 struct type
*encl_type
= value_enclosing_type (arg
);
734 if (value_lazy (arg
))
735 val
= allocate_value_lazy (encl_type
);
737 val
= allocate_value (encl_type
);
738 val
->type
= arg
->type
;
739 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
740 val
->location
= arg
->location
;
741 val
->offset
= arg
->offset
;
742 val
->bitpos
= arg
->bitpos
;
743 val
->bitsize
= arg
->bitsize
;
744 VALUE_FRAME_ID (val
) = VALUE_FRAME_ID (arg
);
745 VALUE_REGNUM (val
) = VALUE_REGNUM (arg
);
746 val
->lazy
= arg
->lazy
;
747 val
->optimized_out
= arg
->optimized_out
;
748 val
->embedded_offset
= value_embedded_offset (arg
);
749 val
->pointed_to_offset
= arg
->pointed_to_offset
;
750 val
->modifiable
= arg
->modifiable
;
751 if (!value_lazy (val
))
753 memcpy (value_contents_all_raw (val
), value_contents_all_raw (arg
),
754 TYPE_LENGTH (value_enclosing_type (arg
)));
757 val
->parent
= arg
->parent
;
759 value_incref (val
->parent
);
760 if (VALUE_LVAL (val
) == lval_computed
)
762 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
764 if (funcs
->copy_closure
)
765 val
->location
.computed
.closure
= funcs
->copy_closure (val
);
771 set_value_component_location (struct value
*component
, struct value
*whole
)
773 if (VALUE_LVAL (whole
) == lval_internalvar
)
774 VALUE_LVAL (component
) = lval_internalvar_component
;
776 VALUE_LVAL (component
) = VALUE_LVAL (whole
);
778 component
->location
= whole
->location
;
779 if (VALUE_LVAL (whole
) == lval_computed
)
781 struct lval_funcs
*funcs
= whole
->location
.computed
.funcs
;
783 if (funcs
->copy_closure
)
784 component
->location
.computed
.closure
= funcs
->copy_closure (whole
);
789 /* Access to the value history. */
791 /* Record a new value in the value history.
792 Returns the absolute history index of the entry.
793 Result of -1 indicates the value was not saved; otherwise it is the
794 value history index of this new item. */
797 record_latest_value (struct value
*val
)
801 /* We don't want this value to have anything to do with the inferior anymore.
802 In particular, "set $1 = 50" should not affect the variable from which
803 the value was taken, and fast watchpoints should be able to assume that
804 a value on the value history never changes. */
805 if (value_lazy (val
))
806 value_fetch_lazy (val
);
807 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
808 from. This is a bit dubious, because then *&$1 does not just return $1
809 but the current contents of that location. c'est la vie... */
813 /* Here we treat value_history_count as origin-zero
814 and applying to the value being stored now. */
816 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
819 struct value_history_chunk
*new
820 = (struct value_history_chunk
*)
821 xmalloc (sizeof (struct value_history_chunk
));
822 memset (new->values
, 0, sizeof new->values
);
823 new->next
= value_history_chain
;
824 value_history_chain
= new;
827 value_history_chain
->values
[i
] = val
;
829 /* Now we regard value_history_count as origin-one
830 and applying to the value just stored. */
832 return ++value_history_count
;
835 /* Return a copy of the value in the history with sequence number NUM. */
838 access_value_history (int num
)
840 struct value_history_chunk
*chunk
;
845 absnum
+= value_history_count
;
850 error (_("The history is empty."));
852 error (_("There is only one value in the history."));
854 error (_("History does not go back to $$%d."), -num
);
856 if (absnum
> value_history_count
)
857 error (_("History has not yet reached $%d."), absnum
);
861 /* Now absnum is always absolute and origin zero. */
863 chunk
= value_history_chain
;
864 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
868 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
872 show_values (char *num_exp
, int from_tty
)
880 /* "show values +" should print from the stored position.
881 "show values <exp>" should print around value number <exp>. */
882 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
883 num
= parse_and_eval_long (num_exp
) - 5;
887 /* "show values" means print the last 10 values. */
888 num
= value_history_count
- 9;
894 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
896 struct value_print_options opts
;
897 val
= access_value_history (i
);
898 printf_filtered (("$%d = "), i
);
899 get_user_print_options (&opts
);
900 value_print (val
, gdb_stdout
, &opts
);
901 printf_filtered (("\n"));
904 /* The next "show values +" should start after what we just printed. */
907 /* Hitting just return after this command should do the same thing as
908 "show values +". If num_exp is null, this is unnecessary, since
909 "show values +" is not useful after "show values". */
910 if (from_tty
&& num_exp
)
917 /* Internal variables. These are variables within the debugger
918 that hold values assigned by debugger commands.
919 The user refers to them with a '$' prefix
920 that does not appear in the variable names stored internally. */
924 struct internalvar
*next
;
927 /* We support various different kinds of content of an internal variable.
928 enum internalvar_kind specifies the kind, and union internalvar_data
929 provides the data associated with this particular kind. */
931 enum internalvar_kind
933 /* The internal variable is empty. */
936 /* The value of the internal variable is provided directly as
937 a GDB value object. */
940 /* A fresh value is computed via a call-back routine on every
941 access to the internal variable. */
942 INTERNALVAR_MAKE_VALUE
,
944 /* The internal variable holds a GDB internal convenience function. */
945 INTERNALVAR_FUNCTION
,
947 /* The variable holds an integer value. */
950 /* The variable holds a pointer value. */
953 /* The variable holds a GDB-provided string. */
958 union internalvar_data
960 /* A value object used with INTERNALVAR_VALUE. */
963 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
964 internalvar_make_value make_value
;
966 /* The internal function used with INTERNALVAR_FUNCTION. */
969 struct internal_function
*function
;
970 /* True if this is the canonical name for the function. */
974 /* An integer value used with INTERNALVAR_INTEGER. */
977 /* If type is non-NULL, it will be used as the type to generate
978 a value for this internal variable. If type is NULL, a default
979 integer type for the architecture is used. */
984 /* A pointer value used with INTERNALVAR_POINTER. */
991 /* A string value used with INTERNALVAR_STRING. */
996 static struct internalvar
*internalvars
;
998 /* If the variable does not already exist create it and give it the value given.
999 If no value is given then the default is zero. */
1001 init_if_undefined_command (char* args
, int from_tty
)
1003 struct internalvar
* intvar
;
1005 /* Parse the expression - this is taken from set_command(). */
1006 struct expression
*expr
= parse_expression (args
);
1007 register struct cleanup
*old_chain
=
1008 make_cleanup (free_current_contents
, &expr
);
1010 /* Validate the expression.
1011 Was the expression an assignment?
1012 Or even an expression at all? */
1013 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
1014 error (_("Init-if-undefined requires an assignment expression."));
1016 /* Extract the variable from the parsed expression.
1017 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
1018 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
1019 error (_("The first parameter to init-if-undefined should be a GDB variable."));
1020 intvar
= expr
->elts
[2].internalvar
;
1022 /* Only evaluate the expression if the lvalue is void.
1023 This may still fail if the expresssion is invalid. */
1024 if (intvar
->kind
== INTERNALVAR_VOID
)
1025 evaluate_expression (expr
);
1027 do_cleanups (old_chain
);
1031 /* Look up an internal variable with name NAME. NAME should not
1032 normally include a dollar sign.
1034 If the specified internal variable does not exist,
1035 the return value is NULL. */
1037 struct internalvar
*
1038 lookup_only_internalvar (const char *name
)
1040 struct internalvar
*var
;
1042 for (var
= internalvars
; var
; var
= var
->next
)
1043 if (strcmp (var
->name
, name
) == 0)
1050 /* Create an internal variable with name NAME and with a void value.
1051 NAME should not normally include a dollar sign. */
1053 struct internalvar
*
1054 create_internalvar (const char *name
)
1056 struct internalvar
*var
;
1057 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
1058 var
->name
= concat (name
, (char *)NULL
);
1059 var
->kind
= INTERNALVAR_VOID
;
1060 var
->next
= internalvars
;
1065 /* Create an internal variable with name NAME and register FUN as the
1066 function that value_of_internalvar uses to create a value whenever
1067 this variable is referenced. NAME should not normally include a
1070 struct internalvar
*
1071 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
1073 struct internalvar
*var
= create_internalvar (name
);
1074 var
->kind
= INTERNALVAR_MAKE_VALUE
;
1075 var
->u
.make_value
= fun
;
1079 /* Look up an internal variable with name NAME. NAME should not
1080 normally include a dollar sign.
1082 If the specified internal variable does not exist,
1083 one is created, with a void value. */
1085 struct internalvar
*
1086 lookup_internalvar (const char *name
)
1088 struct internalvar
*var
;
1090 var
= lookup_only_internalvar (name
);
1094 return create_internalvar (name
);
1097 /* Return current value of internal variable VAR. For variables that
1098 are not inherently typed, use a value type appropriate for GDBARCH. */
1101 value_of_internalvar (struct gdbarch
*gdbarch
, struct internalvar
*var
)
1107 case INTERNALVAR_VOID
:
1108 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1111 case INTERNALVAR_FUNCTION
:
1112 val
= allocate_value (builtin_type (gdbarch
)->internal_fn
);
1115 case INTERNALVAR_INTEGER
:
1116 if (!var
->u
.integer
.type
)
1117 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
1118 var
->u
.integer
.val
);
1120 val
= value_from_longest (var
->u
.integer
.type
, var
->u
.integer
.val
);
1123 case INTERNALVAR_POINTER
:
1124 val
= value_from_pointer (var
->u
.pointer
.type
, var
->u
.pointer
.val
);
1127 case INTERNALVAR_STRING
:
1128 val
= value_cstring (var
->u
.string
, strlen (var
->u
.string
),
1129 builtin_type (gdbarch
)->builtin_char
);
1132 case INTERNALVAR_VALUE
:
1133 val
= value_copy (var
->u
.value
);
1134 if (value_lazy (val
))
1135 value_fetch_lazy (val
);
1138 case INTERNALVAR_MAKE_VALUE
:
1139 val
= (*var
->u
.make_value
) (gdbarch
, var
);
1143 internal_error (__FILE__
, __LINE__
, "bad kind");
1146 /* Change the VALUE_LVAL to lval_internalvar so that future operations
1147 on this value go back to affect the original internal variable.
1149 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
1150 no underlying modifyable state in the internal variable.
1152 Likewise, if the variable's value is a computed lvalue, we want
1153 references to it to produce another computed lvalue, where
1154 references and assignments actually operate through the
1155 computed value's functions.
1157 This means that internal variables with computed values
1158 behave a little differently from other internal variables:
1159 assignments to them don't just replace the previous value
1160 altogether. At the moment, this seems like the behavior we
1163 if (var
->kind
!= INTERNALVAR_MAKE_VALUE
1164 && val
->lval
!= lval_computed
)
1166 VALUE_LVAL (val
) = lval_internalvar
;
1167 VALUE_INTERNALVAR (val
) = var
;
1174 get_internalvar_integer (struct internalvar
*var
, LONGEST
*result
)
1178 case INTERNALVAR_INTEGER
:
1179 *result
= var
->u
.integer
.val
;
1188 get_internalvar_function (struct internalvar
*var
,
1189 struct internal_function
**result
)
1193 case INTERNALVAR_FUNCTION
:
1194 *result
= var
->u
.fn
.function
;
1203 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1204 int bitsize
, struct value
*newval
)
1210 case INTERNALVAR_VALUE
:
1211 addr
= value_contents_writeable (var
->u
.value
);
1214 modify_field (value_type (var
->u
.value
), addr
+ offset
,
1215 value_as_long (newval
), bitpos
, bitsize
);
1217 memcpy (addr
+ offset
, value_contents (newval
),
1218 TYPE_LENGTH (value_type (newval
)));
1222 /* We can never get a component of any other kind. */
1223 internal_error (__FILE__
, __LINE__
, "set_internalvar_component");
1228 set_internalvar (struct internalvar
*var
, struct value
*val
)
1230 enum internalvar_kind new_kind
;
1231 union internalvar_data new_data
= { 0 };
1233 if (var
->kind
== INTERNALVAR_FUNCTION
&& var
->u
.fn
.canonical
)
1234 error (_("Cannot overwrite convenience function %s"), var
->name
);
1236 /* Prepare new contents. */
1237 switch (TYPE_CODE (check_typedef (value_type (val
))))
1239 case TYPE_CODE_VOID
:
1240 new_kind
= INTERNALVAR_VOID
;
1243 case TYPE_CODE_INTERNAL_FUNCTION
:
1244 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1245 new_kind
= INTERNALVAR_FUNCTION
;
1246 get_internalvar_function (VALUE_INTERNALVAR (val
),
1247 &new_data
.fn
.function
);
1248 /* Copies created here are never canonical. */
1252 new_kind
= INTERNALVAR_INTEGER
;
1253 new_data
.integer
.type
= value_type (val
);
1254 new_data
.integer
.val
= value_as_long (val
);
1258 new_kind
= INTERNALVAR_POINTER
;
1259 new_data
.pointer
.type
= value_type (val
);
1260 new_data
.pointer
.val
= value_as_address (val
);
1264 new_kind
= INTERNALVAR_VALUE
;
1265 new_data
.value
= value_copy (val
);
1266 new_data
.value
->modifiable
= 1;
1268 /* Force the value to be fetched from the target now, to avoid problems
1269 later when this internalvar is referenced and the target is gone or
1271 if (value_lazy (new_data
.value
))
1272 value_fetch_lazy (new_data
.value
);
1274 /* Release the value from the value chain to prevent it from being
1275 deleted by free_all_values. From here on this function should not
1276 call error () until new_data is installed into the var->u to avoid
1278 release_value (new_data
.value
);
1282 /* Clean up old contents. */
1283 clear_internalvar (var
);
1286 var
->kind
= new_kind
;
1288 /* End code which must not call error(). */
1292 set_internalvar_integer (struct internalvar
*var
, LONGEST l
)
1294 /* Clean up old contents. */
1295 clear_internalvar (var
);
1297 var
->kind
= INTERNALVAR_INTEGER
;
1298 var
->u
.integer
.type
= NULL
;
1299 var
->u
.integer
.val
= l
;
1303 set_internalvar_string (struct internalvar
*var
, const char *string
)
1305 /* Clean up old contents. */
1306 clear_internalvar (var
);
1308 var
->kind
= INTERNALVAR_STRING
;
1309 var
->u
.string
= xstrdup (string
);
1313 set_internalvar_function (struct internalvar
*var
, struct internal_function
*f
)
1315 /* Clean up old contents. */
1316 clear_internalvar (var
);
1318 var
->kind
= INTERNALVAR_FUNCTION
;
1319 var
->u
.fn
.function
= f
;
1320 var
->u
.fn
.canonical
= 1;
1321 /* Variables installed here are always the canonical version. */
1325 clear_internalvar (struct internalvar
*var
)
1327 /* Clean up old contents. */
1330 case INTERNALVAR_VALUE
:
1331 value_free (var
->u
.value
);
1334 case INTERNALVAR_STRING
:
1335 xfree (var
->u
.string
);
1342 /* Reset to void kind. */
1343 var
->kind
= INTERNALVAR_VOID
;
1347 internalvar_name (struct internalvar
*var
)
1352 static struct internal_function
*
1353 create_internal_function (const char *name
,
1354 internal_function_fn handler
, void *cookie
)
1356 struct internal_function
*ifn
= XNEW (struct internal_function
);
1357 ifn
->name
= xstrdup (name
);
1358 ifn
->handler
= handler
;
1359 ifn
->cookie
= cookie
;
1364 value_internal_function_name (struct value
*val
)
1366 struct internal_function
*ifn
;
1369 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1370 result
= get_internalvar_function (VALUE_INTERNALVAR (val
), &ifn
);
1371 gdb_assert (result
);
1377 call_internal_function (struct gdbarch
*gdbarch
,
1378 const struct language_defn
*language
,
1379 struct value
*func
, int argc
, struct value
**argv
)
1381 struct internal_function
*ifn
;
1384 gdb_assert (VALUE_LVAL (func
) == lval_internalvar
);
1385 result
= get_internalvar_function (VALUE_INTERNALVAR (func
), &ifn
);
1386 gdb_assert (result
);
1388 return (*ifn
->handler
) (gdbarch
, language
, ifn
->cookie
, argc
, argv
);
1391 /* The 'function' command. This does nothing -- it is just a
1392 placeholder to let "help function NAME" work. This is also used as
1393 the implementation of the sub-command that is created when
1394 registering an internal function. */
1396 function_command (char *command
, int from_tty
)
1401 /* Clean up if an internal function's command is destroyed. */
1403 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1409 /* Add a new internal function. NAME is the name of the function; DOC
1410 is a documentation string describing the function. HANDLER is
1411 called when the function is invoked. COOKIE is an arbitrary
1412 pointer which is passed to HANDLER and is intended for "user
1415 add_internal_function (const char *name
, const char *doc
,
1416 internal_function_fn handler
, void *cookie
)
1418 struct cmd_list_element
*cmd
;
1419 struct internal_function
*ifn
;
1420 struct internalvar
*var
= lookup_internalvar (name
);
1422 ifn
= create_internal_function (name
, handler
, cookie
);
1423 set_internalvar_function (var
, ifn
);
1425 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1427 cmd
->destroyer
= function_destroyer
;
1430 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1431 prevent cycles / duplicates. */
1434 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1435 htab_t copied_types
)
1437 if (TYPE_OBJFILE (value
->type
) == objfile
)
1438 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1440 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1441 value
->enclosing_type
= copy_type_recursive (objfile
,
1442 value
->enclosing_type
,
1446 /* Likewise for internal variable VAR. */
1449 preserve_one_internalvar (struct internalvar
*var
, struct objfile
*objfile
,
1450 htab_t copied_types
)
1454 case INTERNALVAR_INTEGER
:
1455 if (var
->u
.integer
.type
&& TYPE_OBJFILE (var
->u
.integer
.type
) == objfile
)
1457 = copy_type_recursive (objfile
, var
->u
.integer
.type
, copied_types
);
1460 case INTERNALVAR_POINTER
:
1461 if (TYPE_OBJFILE (var
->u
.pointer
.type
) == objfile
)
1463 = copy_type_recursive (objfile
, var
->u
.pointer
.type
, copied_types
);
1466 case INTERNALVAR_VALUE
:
1467 preserve_one_value (var
->u
.value
, objfile
, copied_types
);
1472 /* Update the internal variables and value history when OBJFILE is
1473 discarded; we must copy the types out of the objfile. New global types
1474 will be created for every convenience variable which currently points to
1475 this objfile's types, and the convenience variables will be adjusted to
1476 use the new global types. */
1479 preserve_values (struct objfile
*objfile
)
1481 htab_t copied_types
;
1482 struct value_history_chunk
*cur
;
1483 struct internalvar
*var
;
1486 /* Create the hash table. We allocate on the objfile's obstack, since
1487 it is soon to be deleted. */
1488 copied_types
= create_copied_types_hash (objfile
);
1490 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1491 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1493 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1495 for (var
= internalvars
; var
; var
= var
->next
)
1496 preserve_one_internalvar (var
, objfile
, copied_types
);
1498 preserve_python_values (objfile
, copied_types
);
1500 htab_delete (copied_types
);
1504 show_convenience (char *ignore
, int from_tty
)
1506 struct gdbarch
*gdbarch
= get_current_arch ();
1507 struct internalvar
*var
;
1509 struct value_print_options opts
;
1511 get_user_print_options (&opts
);
1512 for (var
= internalvars
; var
; var
= var
->next
)
1518 printf_filtered (("$%s = "), var
->name
);
1519 value_print (value_of_internalvar (gdbarch
, var
), gdb_stdout
,
1521 printf_filtered (("\n"));
1524 printf_unfiltered (_("\
1525 No debugger convenience variables now defined.\n\
1526 Convenience variables have names starting with \"$\";\n\
1527 use \"set\" as in \"set $foo = 5\" to define them.\n"));
1530 /* Extract a value as a C number (either long or double).
1531 Knows how to convert fixed values to double, or
1532 floating values to long.
1533 Does not deallocate the value. */
1536 value_as_long (struct value
*val
)
1538 /* This coerces arrays and functions, which is necessary (e.g.
1539 in disassemble_command). It also dereferences references, which
1540 I suspect is the most logical thing to do. */
1541 val
= coerce_array (val
);
1542 return unpack_long (value_type (val
), value_contents (val
));
1546 value_as_double (struct value
*val
)
1551 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1553 error (_("Invalid floating value found in program."));
1557 /* Extract a value as a C pointer. Does not deallocate the value.
1558 Note that val's type may not actually be a pointer; value_as_long
1559 handles all the cases. */
1561 value_as_address (struct value
*val
)
1563 struct gdbarch
*gdbarch
= get_type_arch (value_type (val
));
1565 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1566 whether we want this to be true eventually. */
1568 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1569 non-address (e.g. argument to "signal", "info break", etc.), or
1570 for pointers to char, in which the low bits *are* significant. */
1571 return gdbarch_addr_bits_remove (gdbarch
, value_as_long (val
));
1574 /* There are several targets (IA-64, PowerPC, and others) which
1575 don't represent pointers to functions as simply the address of
1576 the function's entry point. For example, on the IA-64, a
1577 function pointer points to a two-word descriptor, generated by
1578 the linker, which contains the function's entry point, and the
1579 value the IA-64 "global pointer" register should have --- to
1580 support position-independent code. The linker generates
1581 descriptors only for those functions whose addresses are taken.
1583 On such targets, it's difficult for GDB to convert an arbitrary
1584 function address into a function pointer; it has to either find
1585 an existing descriptor for that function, or call malloc and
1586 build its own. On some targets, it is impossible for GDB to
1587 build a descriptor at all: the descriptor must contain a jump
1588 instruction; data memory cannot be executed; and code memory
1591 Upon entry to this function, if VAL is a value of type `function'
1592 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1593 value_address (val) is the address of the function. This is what
1594 you'll get if you evaluate an expression like `main'. The call
1595 to COERCE_ARRAY below actually does all the usual unary
1596 conversions, which includes converting values of type `function'
1597 to `pointer to function'. This is the challenging conversion
1598 discussed above. Then, `unpack_long' will convert that pointer
1599 back into an address.
1601 So, suppose the user types `disassemble foo' on an architecture
1602 with a strange function pointer representation, on which GDB
1603 cannot build its own descriptors, and suppose further that `foo'
1604 has no linker-built descriptor. The address->pointer conversion
1605 will signal an error and prevent the command from running, even
1606 though the next step would have been to convert the pointer
1607 directly back into the same address.
1609 The following shortcut avoids this whole mess. If VAL is a
1610 function, just return its address directly. */
1611 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
1612 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
1613 return value_address (val
);
1615 val
= coerce_array (val
);
1617 /* Some architectures (e.g. Harvard), map instruction and data
1618 addresses onto a single large unified address space. For
1619 instance: An architecture may consider a large integer in the
1620 range 0x10000000 .. 0x1000ffff to already represent a data
1621 addresses (hence not need a pointer to address conversion) while
1622 a small integer would still need to be converted integer to
1623 pointer to address. Just assume such architectures handle all
1624 integer conversions in a single function. */
1628 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1629 must admonish GDB hackers to make sure its behavior matches the
1630 compiler's, whenever possible.
1632 In general, I think GDB should evaluate expressions the same way
1633 the compiler does. When the user copies an expression out of
1634 their source code and hands it to a `print' command, they should
1635 get the same value the compiler would have computed. Any
1636 deviation from this rule can cause major confusion and annoyance,
1637 and needs to be justified carefully. In other words, GDB doesn't
1638 really have the freedom to do these conversions in clever and
1641 AndrewC pointed out that users aren't complaining about how GDB
1642 casts integers to pointers; they are complaining that they can't
1643 take an address from a disassembly listing and give it to `x/i'.
1644 This is certainly important.
1646 Adding an architecture method like integer_to_address() certainly
1647 makes it possible for GDB to "get it right" in all circumstances
1648 --- the target has complete control over how things get done, so
1649 people can Do The Right Thing for their target without breaking
1650 anyone else. The standard doesn't specify how integers get
1651 converted to pointers; usually, the ABI doesn't either, but
1652 ABI-specific code is a more reasonable place to handle it. */
1654 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
1655 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
1656 && gdbarch_integer_to_address_p (gdbarch
))
1657 return gdbarch_integer_to_address (gdbarch
, value_type (val
),
1658 value_contents (val
));
1660 return unpack_long (value_type (val
), value_contents (val
));
1664 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1665 as a long, or as a double, assuming the raw data is described
1666 by type TYPE. Knows how to convert different sizes of values
1667 and can convert between fixed and floating point. We don't assume
1668 any alignment for the raw data. Return value is in host byte order.
1670 If you want functions and arrays to be coerced to pointers, and
1671 references to be dereferenced, call value_as_long() instead.
1673 C++: It is assumed that the front-end has taken care of
1674 all matters concerning pointers to members. A pointer
1675 to member which reaches here is considered to be equivalent
1676 to an INT (or some size). After all, it is only an offset. */
1679 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
1681 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1682 enum type_code code
= TYPE_CODE (type
);
1683 int len
= TYPE_LENGTH (type
);
1684 int nosign
= TYPE_UNSIGNED (type
);
1688 case TYPE_CODE_TYPEDEF
:
1689 return unpack_long (check_typedef (type
), valaddr
);
1690 case TYPE_CODE_ENUM
:
1691 case TYPE_CODE_FLAGS
:
1692 case TYPE_CODE_BOOL
:
1694 case TYPE_CODE_CHAR
:
1695 case TYPE_CODE_RANGE
:
1696 case TYPE_CODE_MEMBERPTR
:
1698 return extract_unsigned_integer (valaddr
, len
, byte_order
);
1700 return extract_signed_integer (valaddr
, len
, byte_order
);
1703 return extract_typed_floating (valaddr
, type
);
1705 case TYPE_CODE_DECFLOAT
:
1706 /* libdecnumber has a function to convert from decimal to integer, but
1707 it doesn't work when the decimal number has a fractional part. */
1708 return decimal_to_doublest (valaddr
, len
, byte_order
);
1712 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1713 whether we want this to be true eventually. */
1714 return extract_typed_address (valaddr
, type
);
1717 error (_("Value can't be converted to integer."));
1719 return 0; /* Placate lint. */
1722 /* Return a double value from the specified type and address.
1723 INVP points to an int which is set to 0 for valid value,
1724 1 for invalid value (bad float format). In either case,
1725 the returned double is OK to use. Argument is in target
1726 format, result is in host format. */
1729 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
1731 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1732 enum type_code code
;
1736 *invp
= 0; /* Assume valid. */
1737 CHECK_TYPEDEF (type
);
1738 code
= TYPE_CODE (type
);
1739 len
= TYPE_LENGTH (type
);
1740 nosign
= TYPE_UNSIGNED (type
);
1741 if (code
== TYPE_CODE_FLT
)
1743 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1744 floating-point value was valid (using the macro
1745 INVALID_FLOAT). That test/macro have been removed.
1747 It turns out that only the VAX defined this macro and then
1748 only in a non-portable way. Fixing the portability problem
1749 wouldn't help since the VAX floating-point code is also badly
1750 bit-rotten. The target needs to add definitions for the
1751 methods gdbarch_float_format and gdbarch_double_format - these
1752 exactly describe the target floating-point format. The
1753 problem here is that the corresponding floatformat_vax_f and
1754 floatformat_vax_d values these methods should be set to are
1755 also not defined either. Oops!
1757 Hopefully someone will add both the missing floatformat
1758 definitions and the new cases for floatformat_is_valid (). */
1760 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
1766 return extract_typed_floating (valaddr
, type
);
1768 else if (code
== TYPE_CODE_DECFLOAT
)
1769 return decimal_to_doublest (valaddr
, len
, byte_order
);
1772 /* Unsigned -- be sure we compensate for signed LONGEST. */
1773 return (ULONGEST
) unpack_long (type
, valaddr
);
1777 /* Signed -- we are OK with unpack_long. */
1778 return unpack_long (type
, valaddr
);
1782 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1783 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1784 We don't assume any alignment for the raw data. Return value is in
1787 If you want functions and arrays to be coerced to pointers, and
1788 references to be dereferenced, call value_as_address() instead.
1790 C++: It is assumed that the front-end has taken care of
1791 all matters concerning pointers to members. A pointer
1792 to member which reaches here is considered to be equivalent
1793 to an INT (or some size). After all, it is only an offset. */
1796 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
1798 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1799 whether we want this to be true eventually. */
1800 return unpack_long (type
, valaddr
);
1804 /* Get the value of the FIELDN'th field (which must be static) of
1805 TYPE. Return NULL if the field doesn't exist or has been
1809 value_static_field (struct type
*type
, int fieldno
)
1811 struct value
*retval
;
1813 if (TYPE_FIELD_LOC_KIND (type
, fieldno
) == FIELD_LOC_KIND_PHYSADDR
)
1815 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
1816 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1820 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1821 /*TYPE_FIELD_NAME (type, fieldno);*/
1822 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1826 /* With some compilers, e.g. HP aCC, static data members are reported
1827 as non-debuggable symbols */
1828 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
, NULL
, NULL
);
1833 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
1834 SYMBOL_VALUE_ADDRESS (msym
));
1839 /* SYM should never have a SYMBOL_CLASS which will require
1840 read_var_value to use the FRAME parameter. */
1841 if (symbol_read_needs_frame (sym
))
1842 warning (_("static field's value depends on the current "
1843 "frame - bad debug info?"));
1844 retval
= read_var_value (sym
, NULL
);
1846 if (retval
&& VALUE_LVAL (retval
) == lval_memory
)
1847 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
),
1848 value_address (retval
));
1853 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1854 You have to be careful here, since the size of the data area for the value
1855 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1856 than the old enclosing type, you have to allocate more space for the data.
1857 The return value is a pointer to the new version of this value structure. */
1860 value_change_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
1862 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
1864 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
1866 val
->enclosing_type
= new_encl_type
;
1870 /* Given a value ARG1 (offset by OFFSET bytes)
1871 of a struct or union type ARG_TYPE,
1872 extract and return the value of one of its (non-static) fields.
1873 FIELDNO says which field. */
1876 value_primitive_field (struct value
*arg1
, int offset
,
1877 int fieldno
, struct type
*arg_type
)
1882 CHECK_TYPEDEF (arg_type
);
1883 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
1885 /* Call check_typedef on our type to make sure that, if TYPE
1886 is a TYPE_CODE_TYPEDEF, its length is set to the length
1887 of the target type instead of zero. However, we do not
1888 replace the typedef type by the target type, because we want
1889 to keep the typedef in order to be able to print the type
1890 description correctly. */
1891 check_typedef (type
);
1893 /* Handle packed fields */
1895 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
1897 /* Create a new value for the bitfield, with bitpos and bitsize
1898 set. If possible, arrange offset and bitpos so that we can
1899 do a single aligned read of the size of the containing type.
1900 Otherwise, adjust offset to the byte containing the first
1901 bit. Assume that the address, offset, and embedded offset
1902 are sufficiently aligned. */
1903 int bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
);
1904 int container_bitsize
= TYPE_LENGTH (type
) * 8;
1906 v
= allocate_value_lazy (type
);
1907 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
1908 if ((bitpos
% container_bitsize
) + v
->bitsize
<= container_bitsize
1909 && TYPE_LENGTH (type
) <= (int) sizeof (LONGEST
))
1910 v
->bitpos
= bitpos
% container_bitsize
;
1912 v
->bitpos
= bitpos
% 8;
1913 v
->offset
= value_embedded_offset (arg1
)
1914 + (bitpos
- v
->bitpos
) / 8;
1916 value_incref (v
->parent
);
1917 if (!value_lazy (arg1
))
1918 value_fetch_lazy (v
);
1920 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
1922 /* This field is actually a base subobject, so preserve the
1923 entire object's contents for later references to virtual
1926 /* Lazy register values with offsets are not supported. */
1927 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1928 value_fetch_lazy (arg1
);
1930 if (value_lazy (arg1
))
1931 v
= allocate_value_lazy (value_enclosing_type (arg1
));
1934 v
= allocate_value (value_enclosing_type (arg1
));
1935 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
1936 TYPE_LENGTH (value_enclosing_type (arg1
)));
1939 v
->offset
= value_offset (arg1
);
1940 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
1941 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
1945 /* Plain old data member */
1946 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1948 /* Lazy register values with offsets are not supported. */
1949 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1950 value_fetch_lazy (arg1
);
1952 if (value_lazy (arg1
))
1953 v
= allocate_value_lazy (type
);
1956 v
= allocate_value (type
);
1957 memcpy (value_contents_raw (v
),
1958 value_contents_raw (arg1
) + offset
,
1959 TYPE_LENGTH (type
));
1961 v
->offset
= (value_offset (arg1
) + offset
1962 + value_embedded_offset (arg1
));
1964 set_value_component_location (v
, arg1
);
1965 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
1966 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
1970 /* Given a value ARG1 of a struct or union type,
1971 extract and return the value of one of its (non-static) fields.
1972 FIELDNO says which field. */
1975 value_field (struct value
*arg1
, int fieldno
)
1977 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
1980 /* Return a non-virtual function as a value.
1981 F is the list of member functions which contains the desired method.
1982 J is an index into F which provides the desired method.
1984 We only use the symbol for its address, so be happy with either a
1985 full symbol or a minimal symbol.
1989 value_fn_field (struct value
**arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
1993 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
1994 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
1996 struct minimal_symbol
*msym
;
1998 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
2005 gdb_assert (sym
== NULL
);
2006 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
2011 v
= allocate_value (ftype
);
2014 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
2018 /* The minimal symbol might point to a function descriptor;
2019 resolve it to the actual code address instead. */
2020 struct objfile
*objfile
= msymbol_objfile (msym
);
2021 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
2023 set_value_address (v
,
2024 gdbarch_convert_from_func_ptr_addr
2025 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
2030 if (type
!= value_type (*arg1p
))
2031 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
2032 value_addr (*arg1p
)));
2034 /* Move the `this' pointer according to the offset.
2035 VALUE_OFFSET (*arg1p) += offset;
2043 /* Unpack a bitfield of the specified FIELD_TYPE, from the anonymous
2044 object at VALADDR. The bitfield starts at BITPOS bits and contains
2047 Extracting bits depends on endianness of the machine. Compute the
2048 number of least significant bits to discard. For big endian machines,
2049 we compute the total number of bits in the anonymous object, subtract
2050 off the bit count from the MSB of the object to the MSB of the
2051 bitfield, then the size of the bitfield, which leaves the LSB discard
2052 count. For little endian machines, the discard count is simply the
2053 number of bits from the LSB of the anonymous object to the LSB of the
2056 If the field is signed, we also do sign extension. */
2059 unpack_bits_as_long (struct type
*field_type
, const gdb_byte
*valaddr
,
2060 int bitpos
, int bitsize
)
2062 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (field_type
));
2068 /* Read the minimum number of bytes required; there may not be
2069 enough bytes to read an entire ULONGEST. */
2070 CHECK_TYPEDEF (field_type
);
2072 bytes_read
= ((bitpos
% 8) + bitsize
+ 7) / 8;
2074 bytes_read
= TYPE_LENGTH (field_type
);
2076 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8,
2077 bytes_read
, byte_order
);
2079 /* Extract bits. See comment above. */
2081 if (gdbarch_bits_big_endian (get_type_arch (field_type
)))
2082 lsbcount
= (bytes_read
* 8 - bitpos
% 8 - bitsize
);
2084 lsbcount
= (bitpos
% 8);
2087 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
2088 If the field is signed, and is negative, then sign extend. */
2090 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
2092 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
2094 if (!TYPE_UNSIGNED (field_type
))
2096 if (val
& (valmask
^ (valmask
>> 1)))
2105 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
2106 VALADDR. See unpack_bits_as_long for more details. */
2109 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
2111 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
2112 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
2113 struct type
*field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
2115 return unpack_bits_as_long (field_type
, valaddr
, bitpos
, bitsize
);
2118 /* Modify the value of a bitfield. ADDR points to a block of memory in
2119 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
2120 is the desired value of the field, in host byte order. BITPOS and BITSIZE
2121 indicate which bits (in target bit order) comprise the bitfield.
2122 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS+BITSIZE <= lbits, and
2123 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
2126 modify_field (struct type
*type
, gdb_byte
*addr
,
2127 LONGEST fieldval
, int bitpos
, int bitsize
)
2129 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2131 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
2133 /* If a negative fieldval fits in the field in question, chop
2134 off the sign extension bits. */
2135 if ((~fieldval
& ~(mask
>> 1)) == 0)
2138 /* Warn if value is too big to fit in the field in question. */
2139 if (0 != (fieldval
& ~mask
))
2141 /* FIXME: would like to include fieldval in the message, but
2142 we don't have a sprintf_longest. */
2143 warning (_("Value does not fit in %d bits."), bitsize
);
2145 /* Truncate it, otherwise adjoining fields may be corrupted. */
2149 oword
= extract_unsigned_integer (addr
, sizeof oword
, byte_order
);
2151 /* Shifting for bit field depends on endianness of the target machine. */
2152 if (gdbarch_bits_big_endian (get_type_arch (type
)))
2153 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
2155 oword
&= ~(mask
<< bitpos
);
2156 oword
|= fieldval
<< bitpos
;
2158 store_unsigned_integer (addr
, sizeof oword
, byte_order
, oword
);
2161 /* Pack NUM into BUF using a target format of TYPE. */
2164 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
2166 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2169 type
= check_typedef (type
);
2170 len
= TYPE_LENGTH (type
);
2172 switch (TYPE_CODE (type
))
2175 case TYPE_CODE_CHAR
:
2176 case TYPE_CODE_ENUM
:
2177 case TYPE_CODE_FLAGS
:
2178 case TYPE_CODE_BOOL
:
2179 case TYPE_CODE_RANGE
:
2180 case TYPE_CODE_MEMBERPTR
:
2181 store_signed_integer (buf
, len
, byte_order
, num
);
2186 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2190 error (_("Unexpected type (%d) encountered for integer constant."),
2196 /* Convert C numbers into newly allocated values. */
2199 value_from_longest (struct type
*type
, LONGEST num
)
2201 struct value
*val
= allocate_value (type
);
2203 pack_long (value_contents_raw (val
), type
, num
);
2209 /* Create a value representing a pointer of type TYPE to the address
2212 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
2214 struct value
*val
= allocate_value (type
);
2215 store_typed_address (value_contents_raw (val
), check_typedef (type
), addr
);
2220 /* Create a value of type TYPE whose contents come from VALADDR, if it
2221 is non-null, and whose memory address (in the inferior) is
2225 value_from_contents_and_address (struct type
*type
,
2226 const gdb_byte
*valaddr
,
2229 struct value
*v
= allocate_value (type
);
2230 if (valaddr
== NULL
)
2231 set_value_lazy (v
, 1);
2233 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
2234 set_value_address (v
, address
);
2235 VALUE_LVAL (v
) = lval_memory
;
2240 value_from_double (struct type
*type
, DOUBLEST num
)
2242 struct value
*val
= allocate_value (type
);
2243 struct type
*base_type
= check_typedef (type
);
2244 enum type_code code
= TYPE_CODE (base_type
);
2246 if (code
== TYPE_CODE_FLT
)
2248 store_typed_floating (value_contents_raw (val
), base_type
, num
);
2251 error (_("Unexpected type encountered for floating constant."));
2257 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
2259 struct value
*val
= allocate_value (type
);
2261 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
2267 coerce_ref (struct value
*arg
)
2269 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
2270 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
2271 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
2272 unpack_pointer (value_type (arg
),
2273 value_contents (arg
)));
2278 coerce_array (struct value
*arg
)
2282 arg
= coerce_ref (arg
);
2283 type
= check_typedef (value_type (arg
));
2285 switch (TYPE_CODE (type
))
2287 case TYPE_CODE_ARRAY
:
2288 if (current_language
->c_style_arrays
)
2289 arg
= value_coerce_array (arg
);
2291 case TYPE_CODE_FUNC
:
2292 arg
= value_coerce_function (arg
);
2299 /* Return true if the function returning the specified type is using
2300 the convention of returning structures in memory (passing in the
2301 address as a hidden first parameter). */
2304 using_struct_return (struct gdbarch
*gdbarch
,
2305 struct type
*func_type
, struct type
*value_type
)
2307 enum type_code code
= TYPE_CODE (value_type
);
2309 if (code
== TYPE_CODE_ERROR
)
2310 error (_("Function return type unknown."));
2312 if (code
== TYPE_CODE_VOID
)
2313 /* A void return value is never in memory. See also corresponding
2314 code in "print_return_value". */
2317 /* Probe the architecture for the return-value convention. */
2318 return (gdbarch_return_value (gdbarch
, func_type
, value_type
,
2320 != RETURN_VALUE_REGISTER_CONVENTION
);
2323 /* Set the initialized field in a value struct. */
2326 set_value_initialized (struct value
*val
, int status
)
2328 val
->initialized
= status
;
2331 /* Return the initialized field in a value struct. */
2334 value_initialized (struct value
*val
)
2336 return val
->initialized
;
2340 _initialize_values (void)
2342 add_cmd ("convenience", no_class
, show_convenience
, _("\
2343 Debugger convenience (\"$foo\") variables.\n\
2344 These variables are created when you assign them values;\n\
2345 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2347 A few convenience variables are given values automatically:\n\
2348 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2349 \"$__\" holds the contents of the last address examined with \"x\"."),
2352 add_cmd ("values", no_class
, show_values
,
2353 _("Elements of value history around item number IDX (or last ten)."),
2356 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2357 Initialize a convenience variable if necessary.\n\
2358 init-if-undefined VARIABLE = EXPRESSION\n\
2359 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2360 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2361 VARIABLE is already initialized."));
2363 add_prefix_cmd ("function", no_class
, function_command
, _("\
2364 Placeholder command for showing help on convenience functions."),
2365 &functionlist
, "function ", 0, &cmdlist
);