1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
3 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
4 1996, 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
5 2009 Free Software Foundation, Inc.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "arch-utils.h"
24 #include "gdb_string.h"
35 #include "gdb_assert.h"
41 #include "cli/cli-decode.h"
43 #include "python/python.h"
45 /* Prototypes for exported functions. */
47 void _initialize_values (void);
49 /* Definition of a user function. */
50 struct internal_function
52 /* The name of the function. It is a bit odd to have this in the
53 function itself -- the user might use a differently-named
54 convenience variable to hold the function. */
58 internal_function_fn handler
;
60 /* User data for the handler. */
64 static struct cmd_list_element
*functionlist
;
68 /* Type of value; either not an lval, or one of the various
69 different possible kinds of lval. */
72 /* Is it modifiable? Only relevant if lval != not_lval. */
75 /* Location of value (if lval). */
78 /* If lval == lval_memory, this is the address in the inferior.
79 If lval == lval_register, this is the byte offset into the
80 registers structure. */
83 /* Pointer to internal variable. */
84 struct internalvar
*internalvar
;
86 /* If lval == lval_computed, this is a set of function pointers
87 to use to access and describe the value, and a closure pointer
91 struct lval_funcs
*funcs
; /* Functions to call. */
92 void *closure
; /* Closure for those functions to use. */
96 /* Describes offset of a value within lval of a structure in bytes.
97 If lval == lval_memory, this is an offset to the address. If
98 lval == lval_register, this is a further offset from
99 location.address within the registers structure. Note also the
100 member embedded_offset below. */
103 /* Only used for bitfields; number of bits contained in them. */
106 /* Only used for bitfields; position of start of field. For
107 gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
108 gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
111 /* Frame register value is relative to. This will be described in
112 the lval enum above as "lval_register". */
113 struct frame_id frame_id
;
115 /* Type of the value. */
118 /* If a value represents a C++ object, then the `type' field gives
119 the object's compile-time type. If the object actually belongs
120 to some class derived from `type', perhaps with other base
121 classes and additional members, then `type' is just a subobject
122 of the real thing, and the full object is probably larger than
123 `type' would suggest.
125 If `type' is a dynamic class (i.e. one with a vtable), then GDB
126 can actually determine the object's run-time type by looking at
127 the run-time type information in the vtable. When this
128 information is available, we may elect to read in the entire
129 object, for several reasons:
131 - When printing the value, the user would probably rather see the
132 full object, not just the limited portion apparent from the
135 - If `type' has virtual base classes, then even printing `type'
136 alone may require reaching outside the `type' portion of the
137 object to wherever the virtual base class has been stored.
139 When we store the entire object, `enclosing_type' is the run-time
140 type -- the complete object -- and `embedded_offset' is the
141 offset of `type' within that larger type, in bytes. The
142 value_contents() macro takes `embedded_offset' into account, so
143 most GDB code continues to see the `type' portion of the value,
144 just as the inferior would.
146 If `type' is a pointer to an object, then `enclosing_type' is a
147 pointer to the object's run-time type, and `pointed_to_offset' is
148 the offset in bytes from the full object to the pointed-to object
149 -- that is, the value `embedded_offset' would have if we followed
150 the pointer and fetched the complete object. (I don't really see
151 the point. Why not just determine the run-time type when you
152 indirect, and avoid the special case? The contents don't matter
153 until you indirect anyway.)
155 If we're not doing anything fancy, `enclosing_type' is equal to
156 `type', and `embedded_offset' is zero, so everything works
158 struct type
*enclosing_type
;
160 int pointed_to_offset
;
162 /* Values are stored in a chain, so that they can be deleted easily
163 over calls to the inferior. Values assigned to internal
164 variables, put into the value history or exposed to Python are
165 taken off this list. */
168 /* Register number if the value is from a register. */
171 /* If zero, contents of this value are in the contents field. If
172 nonzero, contents are in inferior. If the lval field is lval_memory,
173 the contents are in inferior memory at location.address plus offset.
174 The lval field may also be lval_register.
176 WARNING: This field is used by the code which handles watchpoints
177 (see breakpoint.c) to decide whether a particular value can be
178 watched by hardware watchpoints. If the lazy flag is set for
179 some member of a value chain, it is assumed that this member of
180 the chain doesn't need to be watched as part of watching the
181 value itself. This is how GDB avoids watching the entire struct
182 or array when the user wants to watch a single struct member or
183 array element. If you ever change the way lazy flag is set and
184 reset, be sure to consider this use as well! */
187 /* If nonzero, this is the value of a variable which does not
188 actually exist in the program. */
191 /* If value is a variable, is it initialized or not. */
194 /* Actual contents of the value. Target byte-order. NULL or not
195 valid if lazy is nonzero. */
199 /* Prototypes for local functions. */
201 static void show_values (char *, int);
203 static void show_convenience (char *, int);
206 /* The value-history records all the values printed
207 by print commands during this session. Each chunk
208 records 60 consecutive values. The first chunk on
209 the chain records the most recent values.
210 The total number of values is in value_history_count. */
212 #define VALUE_HISTORY_CHUNK 60
214 struct value_history_chunk
216 struct value_history_chunk
*next
;
217 struct value
*values
[VALUE_HISTORY_CHUNK
];
220 /* Chain of chunks now in use. */
222 static struct value_history_chunk
*value_history_chain
;
224 static int value_history_count
; /* Abs number of last entry stored */
227 /* List of all value objects currently allocated
228 (except for those released by calls to release_value)
229 This is so they can be freed after each command. */
231 static struct value
*all_values
;
233 /* Allocate a lazy value for type TYPE. Its actual content is
234 "lazily" allocated too: the content field of the return value is
235 NULL; it will be allocated when it is fetched from the target. */
238 allocate_value_lazy (struct type
*type
)
241 struct type
*atype
= check_typedef (type
);
243 val
= (struct value
*) xzalloc (sizeof (struct value
));
244 val
->contents
= NULL
;
245 val
->next
= all_values
;
248 val
->enclosing_type
= type
;
249 VALUE_LVAL (val
) = not_lval
;
250 val
->location
.address
= 0;
251 VALUE_FRAME_ID (val
) = null_frame_id
;
255 VALUE_REGNUM (val
) = -1;
257 val
->optimized_out
= 0;
258 val
->embedded_offset
= 0;
259 val
->pointed_to_offset
= 0;
261 val
->initialized
= 1; /* Default to initialized. */
265 /* Allocate the contents of VAL if it has not been allocated yet. */
268 allocate_value_contents (struct value
*val
)
271 val
->contents
= (gdb_byte
*) xzalloc (TYPE_LENGTH (val
->enclosing_type
));
274 /* Allocate a value and its contents for type TYPE. */
277 allocate_value (struct type
*type
)
279 struct value
*val
= allocate_value_lazy (type
);
280 allocate_value_contents (val
);
285 /* Allocate a value that has the correct length
286 for COUNT repetitions of type TYPE. */
289 allocate_repeat_value (struct type
*type
, int count
)
291 int low_bound
= current_language
->string_lower_bound
; /* ??? */
292 /* FIXME-type-allocation: need a way to free this type when we are
294 struct type
*array_type
295 = lookup_array_range_type (type
, low_bound
, count
+ low_bound
- 1);
296 return allocate_value (array_type
);
299 /* Needed if another module needs to maintain its on list of values. */
301 value_prepend_to_list (struct value
**head
, struct value
*val
)
307 /* Needed if another module needs to maintain its on list of values. */
309 value_remove_from_list (struct value
**head
, struct value
*val
)
314 *head
= (*head
)->next
;
316 for (prev
= *head
; prev
->next
; prev
= prev
->next
)
317 if (prev
->next
== val
)
319 prev
->next
= val
->next
;
325 allocate_computed_value (struct type
*type
,
326 struct lval_funcs
*funcs
,
329 struct value
*v
= allocate_value (type
);
330 VALUE_LVAL (v
) = lval_computed
;
331 v
->location
.computed
.funcs
= funcs
;
332 v
->location
.computed
.closure
= closure
;
333 set_value_lazy (v
, 1);
338 /* Accessor methods. */
341 value_next (struct value
*value
)
347 value_type (struct value
*value
)
352 deprecated_set_value_type (struct value
*value
, struct type
*type
)
358 value_offset (struct value
*value
)
360 return value
->offset
;
363 set_value_offset (struct value
*value
, int offset
)
365 value
->offset
= offset
;
369 value_bitpos (struct value
*value
)
371 return value
->bitpos
;
374 set_value_bitpos (struct value
*value
, int bit
)
380 value_bitsize (struct value
*value
)
382 return value
->bitsize
;
385 set_value_bitsize (struct value
*value
, int bit
)
387 value
->bitsize
= bit
;
391 value_contents_raw (struct value
*value
)
393 allocate_value_contents (value
);
394 return value
->contents
+ value
->embedded_offset
;
398 value_contents_all_raw (struct value
*value
)
400 allocate_value_contents (value
);
401 return value
->contents
;
405 value_enclosing_type (struct value
*value
)
407 return value
->enclosing_type
;
411 value_contents_all (struct value
*value
)
414 value_fetch_lazy (value
);
415 return value
->contents
;
419 value_lazy (struct value
*value
)
425 set_value_lazy (struct value
*value
, int val
)
431 value_contents (struct value
*value
)
433 return value_contents_writeable (value
);
437 value_contents_writeable (struct value
*value
)
440 value_fetch_lazy (value
);
441 return value_contents_raw (value
);
444 /* Return non-zero if VAL1 and VAL2 have the same contents. Note that
445 this function is different from value_equal; in C the operator ==
446 can return 0 even if the two values being compared are equal. */
449 value_contents_equal (struct value
*val1
, struct value
*val2
)
455 type1
= check_typedef (value_type (val1
));
456 type2
= check_typedef (value_type (val2
));
457 len
= TYPE_LENGTH (type1
);
458 if (len
!= TYPE_LENGTH (type2
))
461 return (memcmp (value_contents (val1
), value_contents (val2
), len
) == 0);
465 value_optimized_out (struct value
*value
)
467 return value
->optimized_out
;
471 set_value_optimized_out (struct value
*value
, int val
)
473 value
->optimized_out
= val
;
477 value_embedded_offset (struct value
*value
)
479 return value
->embedded_offset
;
483 set_value_embedded_offset (struct value
*value
, int val
)
485 value
->embedded_offset
= val
;
489 value_pointed_to_offset (struct value
*value
)
491 return value
->pointed_to_offset
;
495 set_value_pointed_to_offset (struct value
*value
, int val
)
497 value
->pointed_to_offset
= val
;
501 value_computed_funcs (struct value
*v
)
503 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
505 return v
->location
.computed
.funcs
;
509 value_computed_closure (struct value
*v
)
511 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
513 return v
->location
.computed
.closure
;
517 deprecated_value_lval_hack (struct value
*value
)
523 value_address (struct value
*value
)
525 if (value
->lval
== lval_internalvar
526 || value
->lval
== lval_internalvar_component
)
528 return value
->location
.address
+ value
->offset
;
532 value_raw_address (struct value
*value
)
534 if (value
->lval
== lval_internalvar
535 || value
->lval
== lval_internalvar_component
)
537 return value
->location
.address
;
541 set_value_address (struct value
*value
, CORE_ADDR addr
)
543 gdb_assert (value
->lval
!= lval_internalvar
544 && value
->lval
!= lval_internalvar_component
);
545 value
->location
.address
= addr
;
548 struct internalvar
**
549 deprecated_value_internalvar_hack (struct value
*value
)
551 return &value
->location
.internalvar
;
555 deprecated_value_frame_id_hack (struct value
*value
)
557 return &value
->frame_id
;
561 deprecated_value_regnum_hack (struct value
*value
)
563 return &value
->regnum
;
567 deprecated_value_modifiable (struct value
*value
)
569 return value
->modifiable
;
572 deprecated_set_value_modifiable (struct value
*value
, int modifiable
)
574 value
->modifiable
= modifiable
;
577 /* Return a mark in the value chain. All values allocated after the
578 mark is obtained (except for those released) are subject to being freed
579 if a subsequent value_free_to_mark is passed the mark. */
587 value_free (struct value
*val
)
591 if (VALUE_LVAL (val
) == lval_computed
)
593 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
595 if (funcs
->free_closure
)
596 funcs
->free_closure (val
);
599 xfree (val
->contents
);
604 /* Free all values allocated since MARK was obtained by value_mark
605 (except for those released). */
607 value_free_to_mark (struct value
*mark
)
612 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
620 /* Free all the values that have been allocated (except for those released).
621 Called after each command, successful or not. */
624 free_all_values (void)
629 for (val
= all_values
; val
; val
= next
)
638 /* Remove VAL from the chain all_values
639 so it will not be freed automatically. */
642 release_value (struct value
*val
)
646 if (all_values
== val
)
648 all_values
= val
->next
;
652 for (v
= all_values
; v
; v
= v
->next
)
662 /* Release all values up to mark */
664 value_release_to_mark (struct value
*mark
)
669 for (val
= next
= all_values
; next
; next
= next
->next
)
670 if (next
->next
== mark
)
672 all_values
= next
->next
;
680 /* Return a copy of the value ARG.
681 It contains the same contents, for same memory address,
682 but it's a different block of storage. */
685 value_copy (struct value
*arg
)
687 struct type
*encl_type
= value_enclosing_type (arg
);
690 if (value_lazy (arg
))
691 val
= allocate_value_lazy (encl_type
);
693 val
= allocate_value (encl_type
);
694 val
->type
= arg
->type
;
695 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
696 val
->location
= arg
->location
;
697 val
->offset
= arg
->offset
;
698 val
->bitpos
= arg
->bitpos
;
699 val
->bitsize
= arg
->bitsize
;
700 VALUE_FRAME_ID (val
) = VALUE_FRAME_ID (arg
);
701 VALUE_REGNUM (val
) = VALUE_REGNUM (arg
);
702 val
->lazy
= arg
->lazy
;
703 val
->optimized_out
= arg
->optimized_out
;
704 val
->embedded_offset
= value_embedded_offset (arg
);
705 val
->pointed_to_offset
= arg
->pointed_to_offset
;
706 val
->modifiable
= arg
->modifiable
;
707 if (!value_lazy (val
))
709 memcpy (value_contents_all_raw (val
), value_contents_all_raw (arg
),
710 TYPE_LENGTH (value_enclosing_type (arg
)));
713 if (VALUE_LVAL (val
) == lval_computed
)
715 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
717 if (funcs
->copy_closure
)
718 val
->location
.computed
.closure
= funcs
->copy_closure (val
);
724 set_value_component_location (struct value
*component
, struct value
*whole
)
726 if (VALUE_LVAL (whole
) == lval_internalvar
)
727 VALUE_LVAL (component
) = lval_internalvar_component
;
729 VALUE_LVAL (component
) = VALUE_LVAL (whole
);
731 component
->location
= whole
->location
;
732 if (VALUE_LVAL (whole
) == lval_computed
)
734 struct lval_funcs
*funcs
= whole
->location
.computed
.funcs
;
736 if (funcs
->copy_closure
)
737 component
->location
.computed
.closure
= funcs
->copy_closure (whole
);
742 /* Access to the value history. */
744 /* Record a new value in the value history.
745 Returns the absolute history index of the entry.
746 Result of -1 indicates the value was not saved; otherwise it is the
747 value history index of this new item. */
750 record_latest_value (struct value
*val
)
754 /* We don't want this value to have anything to do with the inferior anymore.
755 In particular, "set $1 = 50" should not affect the variable from which
756 the value was taken, and fast watchpoints should be able to assume that
757 a value on the value history never changes. */
758 if (value_lazy (val
))
759 value_fetch_lazy (val
);
760 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
761 from. This is a bit dubious, because then *&$1 does not just return $1
762 but the current contents of that location. c'est la vie... */
766 /* Here we treat value_history_count as origin-zero
767 and applying to the value being stored now. */
769 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
772 struct value_history_chunk
*new
773 = (struct value_history_chunk
*)
774 xmalloc (sizeof (struct value_history_chunk
));
775 memset (new->values
, 0, sizeof new->values
);
776 new->next
= value_history_chain
;
777 value_history_chain
= new;
780 value_history_chain
->values
[i
] = val
;
782 /* Now we regard value_history_count as origin-one
783 and applying to the value just stored. */
785 return ++value_history_count
;
788 /* Return a copy of the value in the history with sequence number NUM. */
791 access_value_history (int num
)
793 struct value_history_chunk
*chunk
;
798 absnum
+= value_history_count
;
803 error (_("The history is empty."));
805 error (_("There is only one value in the history."));
807 error (_("History does not go back to $$%d."), -num
);
809 if (absnum
> value_history_count
)
810 error (_("History has not yet reached $%d."), absnum
);
814 /* Now absnum is always absolute and origin zero. */
816 chunk
= value_history_chain
;
817 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
821 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
825 show_values (char *num_exp
, int from_tty
)
833 /* "show values +" should print from the stored position.
834 "show values <exp>" should print around value number <exp>. */
835 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
836 num
= parse_and_eval_long (num_exp
) - 5;
840 /* "show values" means print the last 10 values. */
841 num
= value_history_count
- 9;
847 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
849 struct value_print_options opts
;
850 val
= access_value_history (i
);
851 printf_filtered (("$%d = "), i
);
852 get_user_print_options (&opts
);
853 value_print (val
, gdb_stdout
, &opts
);
854 printf_filtered (("\n"));
857 /* The next "show values +" should start after what we just printed. */
860 /* Hitting just return after this command should do the same thing as
861 "show values +". If num_exp is null, this is unnecessary, since
862 "show values +" is not useful after "show values". */
863 if (from_tty
&& num_exp
)
870 /* Internal variables. These are variables within the debugger
871 that hold values assigned by debugger commands.
872 The user refers to them with a '$' prefix
873 that does not appear in the variable names stored internally. */
877 struct internalvar
*next
;
880 /* We support various different kinds of content of an internal variable.
881 enum internalvar_kind specifies the kind, and union internalvar_data
882 provides the data associated with this particular kind. */
884 enum internalvar_kind
886 /* The internal variable is empty. */
889 /* The value of the internal variable is provided directly as
890 a GDB value object. */
893 /* A fresh value is computed via a call-back routine on every
894 access to the internal variable. */
895 INTERNALVAR_MAKE_VALUE
,
897 /* The internal variable holds a GDB internal convenience function. */
898 INTERNALVAR_FUNCTION
,
900 /* The variable holds a simple scalar value. */
903 /* The variable holds a GDB-provided string. */
908 union internalvar_data
910 /* A value object used with INTERNALVAR_VALUE. */
913 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
914 internalvar_make_value make_value
;
916 /* The internal function used with INTERNALVAR_FUNCTION. */
919 struct internal_function
*function
;
920 /* True if this is the canonical name for the function. */
924 /* A scalar value used with INTERNALVAR_SCALAR. */
927 /* If type is non-NULL, it will be used as the type to generate
928 a value for this internal variable. If type is NULL, a default
929 integer type for the architecture is used. */
933 LONGEST l
; /* Used with TYPE_CODE_INT and NULL types. */
934 CORE_ADDR a
; /* Used with TYPE_CODE_PTR types. */
938 /* A string value used with INTERNALVAR_STRING. */
943 static struct internalvar
*internalvars
;
945 /* If the variable does not already exist create it and give it the value given.
946 If no value is given then the default is zero. */
948 init_if_undefined_command (char* args
, int from_tty
)
950 struct internalvar
* intvar
;
952 /* Parse the expression - this is taken from set_command(). */
953 struct expression
*expr
= parse_expression (args
);
954 register struct cleanup
*old_chain
=
955 make_cleanup (free_current_contents
, &expr
);
957 /* Validate the expression.
958 Was the expression an assignment?
959 Or even an expression at all? */
960 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
961 error (_("Init-if-undefined requires an assignment expression."));
963 /* Extract the variable from the parsed expression.
964 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
965 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
966 error (_("The first parameter to init-if-undefined should be a GDB variable."));
967 intvar
= expr
->elts
[2].internalvar
;
969 /* Only evaluate the expression if the lvalue is void.
970 This may still fail if the expresssion is invalid. */
971 if (intvar
->kind
== INTERNALVAR_VOID
)
972 evaluate_expression (expr
);
974 do_cleanups (old_chain
);
978 /* Look up an internal variable with name NAME. NAME should not
979 normally include a dollar sign.
981 If the specified internal variable does not exist,
982 the return value is NULL. */
985 lookup_only_internalvar (const char *name
)
987 struct internalvar
*var
;
989 for (var
= internalvars
; var
; var
= var
->next
)
990 if (strcmp (var
->name
, name
) == 0)
997 /* Create an internal variable with name NAME and with a void value.
998 NAME should not normally include a dollar sign. */
1000 struct internalvar
*
1001 create_internalvar (const char *name
)
1003 struct internalvar
*var
;
1004 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
1005 var
->name
= concat (name
, (char *)NULL
);
1006 var
->kind
= INTERNALVAR_VOID
;
1007 var
->next
= internalvars
;
1012 /* Create an internal variable with name NAME and register FUN as the
1013 function that value_of_internalvar uses to create a value whenever
1014 this variable is referenced. NAME should not normally include a
1017 struct internalvar
*
1018 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
1020 struct internalvar
*var
= create_internalvar (name
);
1021 var
->kind
= INTERNALVAR_MAKE_VALUE
;
1022 var
->u
.make_value
= fun
;
1026 /* Look up an internal variable with name NAME. NAME should not
1027 normally include a dollar sign.
1029 If the specified internal variable does not exist,
1030 one is created, with a void value. */
1032 struct internalvar
*
1033 lookup_internalvar (const char *name
)
1035 struct internalvar
*var
;
1037 var
= lookup_only_internalvar (name
);
1041 return create_internalvar (name
);
1044 /* Return current value of internal variable VAR. For variables that
1045 are not inherently typed, use a value type appropriate for GDBARCH. */
1048 value_of_internalvar (struct gdbarch
*gdbarch
, struct internalvar
*var
)
1054 case INTERNALVAR_VOID
:
1055 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1058 case INTERNALVAR_FUNCTION
:
1059 val
= allocate_value (builtin_type (gdbarch
)->internal_fn
);
1062 case INTERNALVAR_SCALAR
:
1063 if (!var
->u
.scalar
.type
)
1064 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
1065 var
->u
.scalar
.val
.l
);
1066 else if (TYPE_CODE (var
->u
.scalar
.type
) == TYPE_CODE_INT
)
1067 val
= value_from_longest (var
->u
.scalar
.type
, var
->u
.scalar
.val
.l
);
1068 else if (TYPE_CODE (var
->u
.scalar
.type
) == TYPE_CODE_PTR
)
1069 val
= value_from_pointer (var
->u
.scalar
.type
, var
->u
.scalar
.val
.a
);
1071 internal_error (__FILE__
, __LINE__
, "bad type");
1074 case INTERNALVAR_STRING
:
1075 val
= value_cstring (var
->u
.string
, strlen (var
->u
.string
),
1076 builtin_type (gdbarch
)->builtin_char
);
1079 case INTERNALVAR_VALUE
:
1080 val
= value_copy (var
->u
.value
);
1081 if (value_lazy (val
))
1082 value_fetch_lazy (val
);
1085 case INTERNALVAR_MAKE_VALUE
:
1086 val
= (*var
->u
.make_value
) (gdbarch
, var
);
1090 internal_error (__FILE__
, __LINE__
, "bad kind");
1093 /* Change the VALUE_LVAL to lval_internalvar so that future operations
1094 on this value go back to affect the original internal variable.
1096 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
1097 no underlying modifyable state in the internal variable.
1099 Likewise, if the variable's value is a computed lvalue, we want
1100 references to it to produce another computed lvalue, where
1101 references and assignments actually operate through the
1102 computed value's functions.
1104 This means that internal variables with computed values
1105 behave a little differently from other internal variables:
1106 assignments to them don't just replace the previous value
1107 altogether. At the moment, this seems like the behavior we
1110 if (var
->kind
!= INTERNALVAR_MAKE_VALUE
1111 && val
->lval
!= lval_computed
)
1113 VALUE_LVAL (val
) = lval_internalvar
;
1114 VALUE_INTERNALVAR (val
) = var
;
1121 get_internalvar_integer (struct internalvar
*var
, LONGEST
*result
)
1125 case INTERNALVAR_SCALAR
:
1126 if (var
->u
.scalar
.type
== NULL
1127 || TYPE_CODE (var
->u
.scalar
.type
) == TYPE_CODE_INT
)
1129 *result
= var
->u
.scalar
.val
.l
;
1140 get_internalvar_function (struct internalvar
*var
,
1141 struct internal_function
**result
)
1145 case INTERNALVAR_FUNCTION
:
1146 *result
= var
->u
.fn
.function
;
1155 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1156 int bitsize
, struct value
*newval
)
1162 case INTERNALVAR_VALUE
:
1163 addr
= value_contents_writeable (var
->u
.value
);
1166 modify_field (value_type (var
->u
.value
), addr
+ offset
,
1167 value_as_long (newval
), bitpos
, bitsize
);
1169 memcpy (addr
+ offset
, value_contents (newval
),
1170 TYPE_LENGTH (value_type (newval
)));
1174 /* We can never get a component of any other kind. */
1175 internal_error (__FILE__
, __LINE__
, "set_internalvar_component");
1180 set_internalvar (struct internalvar
*var
, struct value
*val
)
1182 enum internalvar_kind new_kind
;
1183 union internalvar_data new_data
= { 0 };
1185 if (var
->kind
== INTERNALVAR_FUNCTION
&& var
->u
.fn
.canonical
)
1186 error (_("Cannot overwrite convenience function %s"), var
->name
);
1188 /* Prepare new contents. */
1189 switch (TYPE_CODE (check_typedef (value_type (val
))))
1191 case TYPE_CODE_VOID
:
1192 new_kind
= INTERNALVAR_VOID
;
1195 case TYPE_CODE_INTERNAL_FUNCTION
:
1196 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1197 new_kind
= INTERNALVAR_FUNCTION
;
1198 get_internalvar_function (VALUE_INTERNALVAR (val
),
1199 &new_data
.fn
.function
);
1200 /* Copies created here are never canonical. */
1204 new_kind
= INTERNALVAR_SCALAR
;
1205 new_data
.scalar
.type
= value_type (val
);
1206 new_data
.scalar
.val
.l
= value_as_long (val
);
1210 new_kind
= INTERNALVAR_SCALAR
;
1211 new_data
.scalar
.type
= value_type (val
);
1212 new_data
.scalar
.val
.a
= value_as_address (val
);
1216 new_kind
= INTERNALVAR_VALUE
;
1217 new_data
.value
= value_copy (val
);
1218 new_data
.value
->modifiable
= 1;
1220 /* Force the value to be fetched from the target now, to avoid problems
1221 later when this internalvar is referenced and the target is gone or
1223 if (value_lazy (new_data
.value
))
1224 value_fetch_lazy (new_data
.value
);
1226 /* Release the value from the value chain to prevent it from being
1227 deleted by free_all_values. From here on this function should not
1228 call error () until new_data is installed into the var->u to avoid
1230 release_value (new_data
.value
);
1234 /* Clean up old contents. */
1235 clear_internalvar (var
);
1238 var
->kind
= new_kind
;
1240 /* End code which must not call error(). */
1244 set_internalvar_integer (struct internalvar
*var
, LONGEST l
)
1246 /* Clean up old contents. */
1247 clear_internalvar (var
);
1249 var
->kind
= INTERNALVAR_SCALAR
;
1250 var
->u
.scalar
.type
= NULL
;
1251 var
->u
.scalar
.val
.l
= l
;
1255 set_internalvar_string (struct internalvar
*var
, const char *string
)
1257 /* Clean up old contents. */
1258 clear_internalvar (var
);
1260 var
->kind
= INTERNALVAR_STRING
;
1261 var
->u
.string
= xstrdup (string
);
1265 set_internalvar_function (struct internalvar
*var
, struct internal_function
*f
)
1267 /* Clean up old contents. */
1268 clear_internalvar (var
);
1270 var
->kind
= INTERNALVAR_FUNCTION
;
1271 var
->u
.fn
.function
= f
;
1272 var
->u
.fn
.canonical
= 1;
1273 /* Variables installed here are always the canonical version. */
1277 clear_internalvar (struct internalvar
*var
)
1279 /* Clean up old contents. */
1282 case INTERNALVAR_VALUE
:
1283 value_free (var
->u
.value
);
1286 case INTERNALVAR_STRING
:
1287 xfree (var
->u
.string
);
1294 /* Reset to void kind. */
1295 var
->kind
= INTERNALVAR_VOID
;
1299 internalvar_name (struct internalvar
*var
)
1304 static struct internal_function
*
1305 create_internal_function (const char *name
,
1306 internal_function_fn handler
, void *cookie
)
1308 struct internal_function
*ifn
= XNEW (struct internal_function
);
1309 ifn
->name
= xstrdup (name
);
1310 ifn
->handler
= handler
;
1311 ifn
->cookie
= cookie
;
1316 value_internal_function_name (struct value
*val
)
1318 struct internal_function
*ifn
;
1321 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1322 result
= get_internalvar_function (VALUE_INTERNALVAR (val
), &ifn
);
1323 gdb_assert (result
);
1329 call_internal_function (struct value
*func
, int argc
, struct value
**argv
)
1331 struct internal_function
*ifn
;
1334 gdb_assert (VALUE_LVAL (func
) == lval_internalvar
);
1335 result
= get_internalvar_function (VALUE_INTERNALVAR (func
), &ifn
);
1336 gdb_assert (result
);
1338 return (*ifn
->handler
) (ifn
->cookie
, argc
, argv
);
1341 /* The 'function' command. This does nothing -- it is just a
1342 placeholder to let "help function NAME" work. This is also used as
1343 the implementation of the sub-command that is created when
1344 registering an internal function. */
1346 function_command (char *command
, int from_tty
)
1351 /* Clean up if an internal function's command is destroyed. */
1353 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1359 /* Add a new internal function. NAME is the name of the function; DOC
1360 is a documentation string describing the function. HANDLER is
1361 called when the function is invoked. COOKIE is an arbitrary
1362 pointer which is passed to HANDLER and is intended for "user
1365 add_internal_function (const char *name
, const char *doc
,
1366 internal_function_fn handler
, void *cookie
)
1368 struct cmd_list_element
*cmd
;
1369 struct internal_function
*ifn
;
1370 struct internalvar
*var
= lookup_internalvar (name
);
1372 ifn
= create_internal_function (name
, handler
, cookie
);
1373 set_internalvar_function (var
, ifn
);
1375 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1377 cmd
->destroyer
= function_destroyer
;
1380 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1381 prevent cycles / duplicates. */
1384 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1385 htab_t copied_types
)
1387 if (TYPE_OBJFILE (value
->type
) == objfile
)
1388 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1390 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1391 value
->enclosing_type
= copy_type_recursive (objfile
,
1392 value
->enclosing_type
,
1396 /* Likewise for internal variable VAR. */
1399 preserve_one_internalvar (struct internalvar
*var
, struct objfile
*objfile
,
1400 htab_t copied_types
)
1404 case INTERNALVAR_SCALAR
:
1405 if (var
->u
.scalar
.type
&& TYPE_OBJFILE (var
->u
.scalar
.type
) == objfile
)
1407 = copy_type_recursive (objfile
, var
->u
.scalar
.type
, copied_types
);
1410 case INTERNALVAR_VALUE
:
1411 preserve_one_value (var
->u
.value
, objfile
, copied_types
);
1416 /* Update the internal variables and value history when OBJFILE is
1417 discarded; we must copy the types out of the objfile. New global types
1418 will be created for every convenience variable which currently points to
1419 this objfile's types, and the convenience variables will be adjusted to
1420 use the new global types. */
1423 preserve_values (struct objfile
*objfile
)
1425 htab_t copied_types
;
1426 struct value_history_chunk
*cur
;
1427 struct internalvar
*var
;
1431 /* Create the hash table. We allocate on the objfile's obstack, since
1432 it is soon to be deleted. */
1433 copied_types
= create_copied_types_hash (objfile
);
1435 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1436 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1438 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1440 for (var
= internalvars
; var
; var
= var
->next
)
1441 preserve_one_internalvar (var
, objfile
, copied_types
);
1443 for (val
= values_in_python
; val
; val
= val
->next
)
1444 preserve_one_value (val
, objfile
, copied_types
);
1446 htab_delete (copied_types
);
1450 show_convenience (char *ignore
, int from_tty
)
1452 struct gdbarch
*gdbarch
= get_current_arch ();
1453 struct internalvar
*var
;
1455 struct value_print_options opts
;
1457 get_user_print_options (&opts
);
1458 for (var
= internalvars
; var
; var
= var
->next
)
1464 printf_filtered (("$%s = "), var
->name
);
1465 value_print (value_of_internalvar (gdbarch
, var
), gdb_stdout
,
1467 printf_filtered (("\n"));
1470 printf_unfiltered (_("\
1471 No debugger convenience variables now defined.\n\
1472 Convenience variables have names starting with \"$\";\n\
1473 use \"set\" as in \"set $foo = 5\" to define them.\n"));
1476 /* Extract a value as a C number (either long or double).
1477 Knows how to convert fixed values to double, or
1478 floating values to long.
1479 Does not deallocate the value. */
1482 value_as_long (struct value
*val
)
1484 /* This coerces arrays and functions, which is necessary (e.g.
1485 in disassemble_command). It also dereferences references, which
1486 I suspect is the most logical thing to do. */
1487 val
= coerce_array (val
);
1488 return unpack_long (value_type (val
), value_contents (val
));
1492 value_as_double (struct value
*val
)
1497 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1499 error (_("Invalid floating value found in program."));
1503 /* Extract a value as a C pointer. Does not deallocate the value.
1504 Note that val's type may not actually be a pointer; value_as_long
1505 handles all the cases. */
1507 value_as_address (struct value
*val
)
1509 struct gdbarch
*gdbarch
= get_type_arch (value_type (val
));
1511 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1512 whether we want this to be true eventually. */
1514 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1515 non-address (e.g. argument to "signal", "info break", etc.), or
1516 for pointers to char, in which the low bits *are* significant. */
1517 return gdbarch_addr_bits_remove (gdbarch
, value_as_long (val
));
1520 /* There are several targets (IA-64, PowerPC, and others) which
1521 don't represent pointers to functions as simply the address of
1522 the function's entry point. For example, on the IA-64, a
1523 function pointer points to a two-word descriptor, generated by
1524 the linker, which contains the function's entry point, and the
1525 value the IA-64 "global pointer" register should have --- to
1526 support position-independent code. The linker generates
1527 descriptors only for those functions whose addresses are taken.
1529 On such targets, it's difficult for GDB to convert an arbitrary
1530 function address into a function pointer; it has to either find
1531 an existing descriptor for that function, or call malloc and
1532 build its own. On some targets, it is impossible for GDB to
1533 build a descriptor at all: the descriptor must contain a jump
1534 instruction; data memory cannot be executed; and code memory
1537 Upon entry to this function, if VAL is a value of type `function'
1538 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1539 value_address (val) is the address of the function. This is what
1540 you'll get if you evaluate an expression like `main'. The call
1541 to COERCE_ARRAY below actually does all the usual unary
1542 conversions, which includes converting values of type `function'
1543 to `pointer to function'. This is the challenging conversion
1544 discussed above. Then, `unpack_long' will convert that pointer
1545 back into an address.
1547 So, suppose the user types `disassemble foo' on an architecture
1548 with a strange function pointer representation, on which GDB
1549 cannot build its own descriptors, and suppose further that `foo'
1550 has no linker-built descriptor. The address->pointer conversion
1551 will signal an error and prevent the command from running, even
1552 though the next step would have been to convert the pointer
1553 directly back into the same address.
1555 The following shortcut avoids this whole mess. If VAL is a
1556 function, just return its address directly. */
1557 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
1558 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
1559 return value_address (val
);
1561 val
= coerce_array (val
);
1563 /* Some architectures (e.g. Harvard), map instruction and data
1564 addresses onto a single large unified address space. For
1565 instance: An architecture may consider a large integer in the
1566 range 0x10000000 .. 0x1000ffff to already represent a data
1567 addresses (hence not need a pointer to address conversion) while
1568 a small integer would still need to be converted integer to
1569 pointer to address. Just assume such architectures handle all
1570 integer conversions in a single function. */
1574 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1575 must admonish GDB hackers to make sure its behavior matches the
1576 compiler's, whenever possible.
1578 In general, I think GDB should evaluate expressions the same way
1579 the compiler does. When the user copies an expression out of
1580 their source code and hands it to a `print' command, they should
1581 get the same value the compiler would have computed. Any
1582 deviation from this rule can cause major confusion and annoyance,
1583 and needs to be justified carefully. In other words, GDB doesn't
1584 really have the freedom to do these conversions in clever and
1587 AndrewC pointed out that users aren't complaining about how GDB
1588 casts integers to pointers; they are complaining that they can't
1589 take an address from a disassembly listing and give it to `x/i'.
1590 This is certainly important.
1592 Adding an architecture method like integer_to_address() certainly
1593 makes it possible for GDB to "get it right" in all circumstances
1594 --- the target has complete control over how things get done, so
1595 people can Do The Right Thing for their target without breaking
1596 anyone else. The standard doesn't specify how integers get
1597 converted to pointers; usually, the ABI doesn't either, but
1598 ABI-specific code is a more reasonable place to handle it. */
1600 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
1601 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
1602 && gdbarch_integer_to_address_p (gdbarch
))
1603 return gdbarch_integer_to_address (gdbarch
, value_type (val
),
1604 value_contents (val
));
1606 return unpack_long (value_type (val
), value_contents (val
));
1610 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1611 as a long, or as a double, assuming the raw data is described
1612 by type TYPE. Knows how to convert different sizes of values
1613 and can convert between fixed and floating point. We don't assume
1614 any alignment for the raw data. Return value is in host byte order.
1616 If you want functions and arrays to be coerced to pointers, and
1617 references to be dereferenced, call value_as_long() instead.
1619 C++: It is assumed that the front-end has taken care of
1620 all matters concerning pointers to members. A pointer
1621 to member which reaches here is considered to be equivalent
1622 to an INT (or some size). After all, it is only an offset. */
1625 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
1627 enum type_code code
= TYPE_CODE (type
);
1628 int len
= TYPE_LENGTH (type
);
1629 int nosign
= TYPE_UNSIGNED (type
);
1633 case TYPE_CODE_TYPEDEF
:
1634 return unpack_long (check_typedef (type
), valaddr
);
1635 case TYPE_CODE_ENUM
:
1636 case TYPE_CODE_FLAGS
:
1637 case TYPE_CODE_BOOL
:
1639 case TYPE_CODE_CHAR
:
1640 case TYPE_CODE_RANGE
:
1641 case TYPE_CODE_MEMBERPTR
:
1643 return extract_unsigned_integer (valaddr
, len
);
1645 return extract_signed_integer (valaddr
, len
);
1648 return extract_typed_floating (valaddr
, type
);
1650 case TYPE_CODE_DECFLOAT
:
1651 /* libdecnumber has a function to convert from decimal to integer, but
1652 it doesn't work when the decimal number has a fractional part. */
1653 return decimal_to_doublest (valaddr
, len
);
1657 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1658 whether we want this to be true eventually. */
1659 return extract_typed_address (valaddr
, type
);
1662 error (_("Value can't be converted to integer."));
1664 return 0; /* Placate lint. */
1667 /* Return a double value from the specified type and address.
1668 INVP points to an int which is set to 0 for valid value,
1669 1 for invalid value (bad float format). In either case,
1670 the returned double is OK to use. Argument is in target
1671 format, result is in host format. */
1674 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
1676 enum type_code code
;
1680 *invp
= 0; /* Assume valid. */
1681 CHECK_TYPEDEF (type
);
1682 code
= TYPE_CODE (type
);
1683 len
= TYPE_LENGTH (type
);
1684 nosign
= TYPE_UNSIGNED (type
);
1685 if (code
== TYPE_CODE_FLT
)
1687 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1688 floating-point value was valid (using the macro
1689 INVALID_FLOAT). That test/macro have been removed.
1691 It turns out that only the VAX defined this macro and then
1692 only in a non-portable way. Fixing the portability problem
1693 wouldn't help since the VAX floating-point code is also badly
1694 bit-rotten. The target needs to add definitions for the
1695 methods gdbarch_float_format and gdbarch_double_format - these
1696 exactly describe the target floating-point format. The
1697 problem here is that the corresponding floatformat_vax_f and
1698 floatformat_vax_d values these methods should be set to are
1699 also not defined either. Oops!
1701 Hopefully someone will add both the missing floatformat
1702 definitions and the new cases for floatformat_is_valid (). */
1704 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
1710 return extract_typed_floating (valaddr
, type
);
1712 else if (code
== TYPE_CODE_DECFLOAT
)
1713 return decimal_to_doublest (valaddr
, len
);
1716 /* Unsigned -- be sure we compensate for signed LONGEST. */
1717 return (ULONGEST
) unpack_long (type
, valaddr
);
1721 /* Signed -- we are OK with unpack_long. */
1722 return unpack_long (type
, valaddr
);
1726 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1727 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1728 We don't assume any alignment for the raw data. Return value is in
1731 If you want functions and arrays to be coerced to pointers, and
1732 references to be dereferenced, call value_as_address() instead.
1734 C++: It is assumed that the front-end has taken care of
1735 all matters concerning pointers to members. A pointer
1736 to member which reaches here is considered to be equivalent
1737 to an INT (or some size). After all, it is only an offset. */
1740 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
1742 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1743 whether we want this to be true eventually. */
1744 return unpack_long (type
, valaddr
);
1748 /* Get the value of the FIELDN'th field (which must be static) of
1749 TYPE. Return NULL if the field doesn't exist or has been
1753 value_static_field (struct type
*type
, int fieldno
)
1755 struct value
*retval
;
1757 if (TYPE_FIELD_LOC_KIND (type
, fieldno
) == FIELD_LOC_KIND_PHYSADDR
)
1759 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1760 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1764 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1765 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1768 /* With some compilers, e.g. HP aCC, static data members are reported
1769 as non-debuggable symbols */
1770 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
, NULL
, NULL
);
1775 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1776 SYMBOL_VALUE_ADDRESS (msym
));
1781 /* SYM should never have a SYMBOL_CLASS which will require
1782 read_var_value to use the FRAME parameter. */
1783 if (symbol_read_needs_frame (sym
))
1784 warning (_("static field's value depends on the current "
1785 "frame - bad debug info?"));
1786 retval
= read_var_value (sym
, NULL
);
1788 if (retval
&& VALUE_LVAL (retval
) == lval_memory
)
1789 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
),
1790 value_address (retval
));
1795 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1796 You have to be careful here, since the size of the data area for the value
1797 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1798 than the old enclosing type, you have to allocate more space for the data.
1799 The return value is a pointer to the new version of this value structure. */
1802 value_change_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
1804 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
1806 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
1808 val
->enclosing_type
= new_encl_type
;
1812 /* Given a value ARG1 (offset by OFFSET bytes)
1813 of a struct or union type ARG_TYPE,
1814 extract and return the value of one of its (non-static) fields.
1815 FIELDNO says which field. */
1818 value_primitive_field (struct value
*arg1
, int offset
,
1819 int fieldno
, struct type
*arg_type
)
1824 CHECK_TYPEDEF (arg_type
);
1825 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
1827 /* Handle packed fields */
1829 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
1831 v
= value_from_longest (type
,
1832 unpack_field_as_long (arg_type
,
1833 value_contents (arg1
)
1836 v
->bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
) % 8;
1837 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
1838 v
->offset
= value_offset (arg1
) + offset
1839 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1841 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
1843 /* This field is actually a base subobject, so preserve the
1844 entire object's contents for later references to virtual
1847 /* Lazy register values with offsets are not supported. */
1848 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1849 value_fetch_lazy (arg1
);
1851 if (value_lazy (arg1
))
1852 v
= allocate_value_lazy (value_enclosing_type (arg1
));
1855 v
= allocate_value (value_enclosing_type (arg1
));
1856 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
1857 TYPE_LENGTH (value_enclosing_type (arg1
)));
1860 v
->offset
= value_offset (arg1
);
1861 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
1862 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
1866 /* Plain old data member */
1867 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1869 /* Lazy register values with offsets are not supported. */
1870 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1871 value_fetch_lazy (arg1
);
1873 if (value_lazy (arg1
))
1874 v
= allocate_value_lazy (type
);
1877 v
= allocate_value (type
);
1878 memcpy (value_contents_raw (v
),
1879 value_contents_raw (arg1
) + offset
,
1880 TYPE_LENGTH (type
));
1882 v
->offset
= (value_offset (arg1
) + offset
1883 + value_embedded_offset (arg1
));
1885 set_value_component_location (v
, arg1
);
1886 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
1887 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
1891 /* Given a value ARG1 of a struct or union type,
1892 extract and return the value of one of its (non-static) fields.
1893 FIELDNO says which field. */
1896 value_field (struct value
*arg1
, int fieldno
)
1898 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
1901 /* Return a non-virtual function as a value.
1902 F is the list of member functions which contains the desired method.
1903 J is an index into F which provides the desired method.
1905 We only use the symbol for its address, so be happy with either a
1906 full symbol or a minimal symbol.
1910 value_fn_field (struct value
**arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
1914 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
1915 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
1917 struct minimal_symbol
*msym
;
1919 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
1926 gdb_assert (sym
== NULL
);
1927 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
1932 v
= allocate_value (ftype
);
1935 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
1939 /* The minimal symbol might point to a function descriptor;
1940 resolve it to the actual code address instead. */
1941 struct objfile
*objfile
= msymbol_objfile (msym
);
1942 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
1944 set_value_address (v
,
1945 gdbarch_convert_from_func_ptr_addr
1946 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
1951 if (type
!= value_type (*arg1p
))
1952 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
1953 value_addr (*arg1p
)));
1955 /* Move the `this' pointer according to the offset.
1956 VALUE_OFFSET (*arg1p) += offset;
1964 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
1967 Extracting bits depends on endianness of the machine. Compute the
1968 number of least significant bits to discard. For big endian machines,
1969 we compute the total number of bits in the anonymous object, subtract
1970 off the bit count from the MSB of the object to the MSB of the
1971 bitfield, then the size of the bitfield, which leaves the LSB discard
1972 count. For little endian machines, the discard count is simply the
1973 number of bits from the LSB of the anonymous object to the LSB of the
1976 If the field is signed, we also do sign extension. */
1979 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
1983 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
1984 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
1986 struct type
*field_type
;
1988 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8, sizeof (val
));
1989 field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
1990 CHECK_TYPEDEF (field_type
);
1992 /* Extract bits. See comment above. */
1994 if (gdbarch_bits_big_endian (get_type_arch (type
)))
1995 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
1997 lsbcount
= (bitpos
% 8);
2000 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
2001 If the field is signed, and is negative, then sign extend. */
2003 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
2005 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
2007 if (!TYPE_UNSIGNED (field_type
))
2009 if (val
& (valmask
^ (valmask
>> 1)))
2018 /* Modify the value of a bitfield. ADDR points to a block of memory in
2019 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
2020 is the desired value of the field, in host byte order. BITPOS and BITSIZE
2021 indicate which bits (in target bit order) comprise the bitfield.
2022 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS+BITSIZE <= lbits, and
2023 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
2026 modify_field (struct type
*type
, gdb_byte
*addr
,
2027 LONGEST fieldval
, int bitpos
, int bitsize
)
2030 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
2032 /* If a negative fieldval fits in the field in question, chop
2033 off the sign extension bits. */
2034 if ((~fieldval
& ~(mask
>> 1)) == 0)
2037 /* Warn if value is too big to fit in the field in question. */
2038 if (0 != (fieldval
& ~mask
))
2040 /* FIXME: would like to include fieldval in the message, but
2041 we don't have a sprintf_longest. */
2042 warning (_("Value does not fit in %d bits."), bitsize
);
2044 /* Truncate it, otherwise adjoining fields may be corrupted. */
2048 oword
= extract_unsigned_integer (addr
, sizeof oword
);
2050 /* Shifting for bit field depends on endianness of the target machine. */
2051 if (gdbarch_bits_big_endian (get_type_arch (type
)))
2052 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
2054 oword
&= ~(mask
<< bitpos
);
2055 oword
|= fieldval
<< bitpos
;
2057 store_unsigned_integer (addr
, sizeof oword
, oword
);
2060 /* Pack NUM into BUF using a target format of TYPE. */
2063 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
2067 type
= check_typedef (type
);
2068 len
= TYPE_LENGTH (type
);
2070 switch (TYPE_CODE (type
))
2073 case TYPE_CODE_CHAR
:
2074 case TYPE_CODE_ENUM
:
2075 case TYPE_CODE_FLAGS
:
2076 case TYPE_CODE_BOOL
:
2077 case TYPE_CODE_RANGE
:
2078 case TYPE_CODE_MEMBERPTR
:
2079 store_signed_integer (buf
, len
, num
);
2084 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2088 error (_("Unexpected type (%d) encountered for integer constant."),
2094 /* Convert C numbers into newly allocated values. */
2097 value_from_longest (struct type
*type
, LONGEST num
)
2099 struct value
*val
= allocate_value (type
);
2101 pack_long (value_contents_raw (val
), type
, num
);
2107 /* Create a value representing a pointer of type TYPE to the address
2110 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
2112 struct value
*val
= allocate_value (type
);
2113 store_typed_address (value_contents_raw (val
), type
, addr
);
2118 /* Create a value of type TYPE whose contents come from VALADDR, if it
2119 is non-null, and whose memory address (in the inferior) is
2123 value_from_contents_and_address (struct type
*type
,
2124 const gdb_byte
*valaddr
,
2127 struct value
*v
= allocate_value (type
);
2128 if (valaddr
== NULL
)
2129 set_value_lazy (v
, 1);
2131 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
2132 set_value_address (v
, address
);
2133 VALUE_LVAL (v
) = lval_memory
;
2138 value_from_double (struct type
*type
, DOUBLEST num
)
2140 struct value
*val
= allocate_value (type
);
2141 struct type
*base_type
= check_typedef (type
);
2142 enum type_code code
= TYPE_CODE (base_type
);
2143 int len
= TYPE_LENGTH (base_type
);
2145 if (code
== TYPE_CODE_FLT
)
2147 store_typed_floating (value_contents_raw (val
), base_type
, num
);
2150 error (_("Unexpected type encountered for floating constant."));
2156 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
2158 struct value
*val
= allocate_value (type
);
2160 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
2166 coerce_ref (struct value
*arg
)
2168 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
2169 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
2170 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
2171 unpack_pointer (value_type (arg
),
2172 value_contents (arg
)));
2177 coerce_array (struct value
*arg
)
2181 arg
= coerce_ref (arg
);
2182 type
= check_typedef (value_type (arg
));
2184 switch (TYPE_CODE (type
))
2186 case TYPE_CODE_ARRAY
:
2187 if (current_language
->c_style_arrays
)
2188 arg
= value_coerce_array (arg
);
2190 case TYPE_CODE_FUNC
:
2191 arg
= value_coerce_function (arg
);
2198 /* Return true if the function returning the specified type is using
2199 the convention of returning structures in memory (passing in the
2200 address as a hidden first parameter). */
2203 using_struct_return (struct gdbarch
*gdbarch
,
2204 struct type
*func_type
, struct type
*value_type
)
2206 enum type_code code
= TYPE_CODE (value_type
);
2208 if (code
== TYPE_CODE_ERROR
)
2209 error (_("Function return type unknown."));
2211 if (code
== TYPE_CODE_VOID
)
2212 /* A void return value is never in memory. See also corresponding
2213 code in "print_return_value". */
2216 /* Probe the architecture for the return-value convention. */
2217 return (gdbarch_return_value (gdbarch
, func_type
, value_type
,
2219 != RETURN_VALUE_REGISTER_CONVENTION
);
2222 /* Set the initialized field in a value struct. */
2225 set_value_initialized (struct value
*val
, int status
)
2227 val
->initialized
= status
;
2230 /* Return the initialized field in a value struct. */
2233 value_initialized (struct value
*val
)
2235 return val
->initialized
;
2239 _initialize_values (void)
2241 add_cmd ("convenience", no_class
, show_convenience
, _("\
2242 Debugger convenience (\"$foo\") variables.\n\
2243 These variables are created when you assign them values;\n\
2244 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2246 A few convenience variables are given values automatically:\n\
2247 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2248 \"$__\" holds the contents of the last address examined with \"x\"."),
2251 add_cmd ("values", no_class
, show_values
,
2252 _("Elements of value history around item number IDX (or last ten)."),
2255 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2256 Initialize a convenience variable if necessary.\n\
2257 init-if-undefined VARIABLE = EXPRESSION\n\
2258 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2259 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2260 VARIABLE is already initialized."));
2262 add_prefix_cmd ("function", no_class
, function_command
, _("\
2263 Placeholder command for showing help on convenience functions."),
2264 &functionlist
, "function ", 0, &cmdlist
);