1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
3 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
4 1996, 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
5 2009 Free Software Foundation, Inc.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "arch-utils.h"
24 #include "gdb_string.h"
35 #include "gdb_assert.h"
41 #include "cli/cli-decode.h"
43 #include "python/python.h"
45 /* Prototypes for exported functions. */
47 void _initialize_values (void);
49 /* Definition of a user function. */
50 struct internal_function
52 /* The name of the function. It is a bit odd to have this in the
53 function itself -- the user might use a differently-named
54 convenience variable to hold the function. */
58 internal_function_fn handler
;
60 /* User data for the handler. */
64 static struct cmd_list_element
*functionlist
;
68 /* Type of value; either not an lval, or one of the various
69 different possible kinds of lval. */
72 /* Is it modifiable? Only relevant if lval != not_lval. */
75 /* Location of value (if lval). */
78 /* If lval == lval_memory, this is the address in the inferior.
79 If lval == lval_register, this is the byte offset into the
80 registers structure. */
83 /* Pointer to internal variable. */
84 struct internalvar
*internalvar
;
86 /* If lval == lval_computed, this is a set of function pointers
87 to use to access and describe the value, and a closure pointer
91 struct lval_funcs
*funcs
; /* Functions to call. */
92 void *closure
; /* Closure for those functions to use. */
96 /* Describes offset of a value within lval of a structure in bytes.
97 If lval == lval_memory, this is an offset to the address. If
98 lval == lval_register, this is a further offset from
99 location.address within the registers structure. Note also the
100 member embedded_offset below. */
103 /* Only used for bitfields; number of bits contained in them. */
106 /* Only used for bitfields; position of start of field. For
107 gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
108 gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
111 /* Only used for bitfields; the containing value. This allows a
112 single read from the target when displaying multiple
114 struct value
*parent
;
116 /* Frame register value is relative to. This will be described in
117 the lval enum above as "lval_register". */
118 struct frame_id frame_id
;
120 /* Type of the value. */
123 /* If a value represents a C++ object, then the `type' field gives
124 the object's compile-time type. If the object actually belongs
125 to some class derived from `type', perhaps with other base
126 classes and additional members, then `type' is just a subobject
127 of the real thing, and the full object is probably larger than
128 `type' would suggest.
130 If `type' is a dynamic class (i.e. one with a vtable), then GDB
131 can actually determine the object's run-time type by looking at
132 the run-time type information in the vtable. When this
133 information is available, we may elect to read in the entire
134 object, for several reasons:
136 - When printing the value, the user would probably rather see the
137 full object, not just the limited portion apparent from the
140 - If `type' has virtual base classes, then even printing `type'
141 alone may require reaching outside the `type' portion of the
142 object to wherever the virtual base class has been stored.
144 When we store the entire object, `enclosing_type' is the run-time
145 type -- the complete object -- and `embedded_offset' is the
146 offset of `type' within that larger type, in bytes. The
147 value_contents() macro takes `embedded_offset' into account, so
148 most GDB code continues to see the `type' portion of the value,
149 just as the inferior would.
151 If `type' is a pointer to an object, then `enclosing_type' is a
152 pointer to the object's run-time type, and `pointed_to_offset' is
153 the offset in bytes from the full object to the pointed-to object
154 -- that is, the value `embedded_offset' would have if we followed
155 the pointer and fetched the complete object. (I don't really see
156 the point. Why not just determine the run-time type when you
157 indirect, and avoid the special case? The contents don't matter
158 until you indirect anyway.)
160 If we're not doing anything fancy, `enclosing_type' is equal to
161 `type', and `embedded_offset' is zero, so everything works
163 struct type
*enclosing_type
;
165 int pointed_to_offset
;
167 /* Values are stored in a chain, so that they can be deleted easily
168 over calls to the inferior. Values assigned to internal
169 variables, put into the value history or exposed to Python are
170 taken off this list. */
173 /* Register number if the value is from a register. */
176 /* If zero, contents of this value are in the contents field. If
177 nonzero, contents are in inferior. If the lval field is lval_memory,
178 the contents are in inferior memory at location.address plus offset.
179 The lval field may also be lval_register.
181 WARNING: This field is used by the code which handles watchpoints
182 (see breakpoint.c) to decide whether a particular value can be
183 watched by hardware watchpoints. If the lazy flag is set for
184 some member of a value chain, it is assumed that this member of
185 the chain doesn't need to be watched as part of watching the
186 value itself. This is how GDB avoids watching the entire struct
187 or array when the user wants to watch a single struct member or
188 array element. If you ever change the way lazy flag is set and
189 reset, be sure to consider this use as well! */
192 /* If nonzero, this is the value of a variable which does not
193 actually exist in the program. */
196 /* If value is a variable, is it initialized or not. */
199 /* 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
)
257 struct type
*atype
= check_typedef (type
);
259 val
= (struct value
*) xzalloc (sizeof (struct value
));
260 val
->contents
= NULL
;
261 val
->next
= all_values
;
264 val
->enclosing_type
= type
;
265 VALUE_LVAL (val
) = not_lval
;
266 val
->location
.address
= 0;
267 VALUE_FRAME_ID (val
) = null_frame_id
;
271 VALUE_REGNUM (val
) = -1;
273 val
->optimized_out
= 0;
274 val
->embedded_offset
= 0;
275 val
->pointed_to_offset
= 0;
277 val
->initialized
= 1; /* Default to initialized. */
279 /* Values start out on the all_values chain. */
280 val
->reference_count
= 1;
285 /* Allocate the contents of VAL if it has not been allocated yet. */
288 allocate_value_contents (struct value
*val
)
291 val
->contents
= (gdb_byte
*) xzalloc (TYPE_LENGTH (val
->enclosing_type
));
294 /* Allocate a value and its contents for type TYPE. */
297 allocate_value (struct type
*type
)
299 struct value
*val
= allocate_value_lazy (type
);
300 allocate_value_contents (val
);
305 /* Allocate a value that has the correct length
306 for COUNT repetitions of type TYPE. */
309 allocate_repeat_value (struct type
*type
, int count
)
311 int low_bound
= current_language
->string_lower_bound
; /* ??? */
312 /* FIXME-type-allocation: need a way to free this type when we are
314 struct type
*array_type
315 = lookup_array_range_type (type
, low_bound
, count
+ low_bound
- 1);
316 return allocate_value (array_type
);
320 allocate_computed_value (struct type
*type
,
321 struct lval_funcs
*funcs
,
324 struct value
*v
= allocate_value (type
);
325 VALUE_LVAL (v
) = lval_computed
;
326 v
->location
.computed
.funcs
= funcs
;
327 v
->location
.computed
.closure
= closure
;
328 set_value_lazy (v
, 1);
333 /* Accessor methods. */
336 value_next (struct value
*value
)
342 value_type (struct value
*value
)
347 deprecated_set_value_type (struct value
*value
, struct type
*type
)
353 value_offset (struct value
*value
)
355 return value
->offset
;
358 set_value_offset (struct value
*value
, int offset
)
360 value
->offset
= offset
;
364 value_bitpos (struct value
*value
)
366 return value
->bitpos
;
369 set_value_bitpos (struct value
*value
, int bit
)
375 value_bitsize (struct value
*value
)
377 return value
->bitsize
;
380 set_value_bitsize (struct value
*value
, int bit
)
382 value
->bitsize
= bit
;
386 value_parent (struct value
*value
)
388 return value
->parent
;
392 value_contents_raw (struct value
*value
)
394 allocate_value_contents (value
);
395 return value
->contents
+ value
->embedded_offset
;
399 value_contents_all_raw (struct value
*value
)
401 allocate_value_contents (value
);
402 return value
->contents
;
406 value_enclosing_type (struct value
*value
)
408 return value
->enclosing_type
;
412 value_contents_all (struct value
*value
)
415 value_fetch_lazy (value
);
416 return value
->contents
;
420 value_lazy (struct value
*value
)
426 set_value_lazy (struct value
*value
, int val
)
432 value_stack (struct value
*value
)
438 set_value_stack (struct value
*value
, int val
)
444 value_contents (struct value
*value
)
446 return value_contents_writeable (value
);
450 value_contents_writeable (struct value
*value
)
453 value_fetch_lazy (value
);
454 return value_contents_raw (value
);
457 /* Return non-zero if VAL1 and VAL2 have the same contents. Note that
458 this function is different from value_equal; in C the operator ==
459 can return 0 even if the two values being compared are equal. */
462 value_contents_equal (struct value
*val1
, struct value
*val2
)
468 type1
= check_typedef (value_type (val1
));
469 type2
= check_typedef (value_type (val2
));
470 len
= TYPE_LENGTH (type1
);
471 if (len
!= TYPE_LENGTH (type2
))
474 return (memcmp (value_contents (val1
), value_contents (val2
), len
) == 0);
478 value_optimized_out (struct value
*value
)
480 return value
->optimized_out
;
484 set_value_optimized_out (struct value
*value
, int val
)
486 value
->optimized_out
= val
;
490 value_embedded_offset (struct value
*value
)
492 return value
->embedded_offset
;
496 set_value_embedded_offset (struct value
*value
, int val
)
498 value
->embedded_offset
= val
;
502 value_pointed_to_offset (struct value
*value
)
504 return value
->pointed_to_offset
;
508 set_value_pointed_to_offset (struct value
*value
, int val
)
510 value
->pointed_to_offset
= val
;
514 value_computed_funcs (struct value
*v
)
516 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
518 return v
->location
.computed
.funcs
;
522 value_computed_closure (struct value
*v
)
524 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
526 return v
->location
.computed
.closure
;
530 deprecated_value_lval_hack (struct value
*value
)
536 value_address (struct value
*value
)
538 if (value
->lval
== lval_internalvar
539 || value
->lval
== lval_internalvar_component
)
541 return value
->location
.address
+ value
->offset
;
545 value_raw_address (struct value
*value
)
547 if (value
->lval
== lval_internalvar
548 || value
->lval
== lval_internalvar_component
)
550 return value
->location
.address
;
554 set_value_address (struct value
*value
, CORE_ADDR addr
)
556 gdb_assert (value
->lval
!= lval_internalvar
557 && value
->lval
!= lval_internalvar_component
);
558 value
->location
.address
= addr
;
561 struct internalvar
**
562 deprecated_value_internalvar_hack (struct value
*value
)
564 return &value
->location
.internalvar
;
568 deprecated_value_frame_id_hack (struct value
*value
)
570 return &value
->frame_id
;
574 deprecated_value_regnum_hack (struct value
*value
)
576 return &value
->regnum
;
580 deprecated_value_modifiable (struct value
*value
)
582 return value
->modifiable
;
585 deprecated_set_value_modifiable (struct value
*value
, int modifiable
)
587 value
->modifiable
= modifiable
;
590 /* Return a mark in the value chain. All values allocated after the
591 mark is obtained (except for those released) are subject to being freed
592 if a subsequent value_free_to_mark is passed the mark. */
599 /* Take a reference to VAL. VAL will not be deallocated until all
600 references are released. */
603 value_incref (struct value
*val
)
605 val
->reference_count
++;
608 /* Release a reference to VAL, which was acquired with value_incref.
609 This function is also called to deallocate values from the value
613 value_free (struct value
*val
)
617 gdb_assert (val
->reference_count
> 0);
618 val
->reference_count
--;
619 if (val
->reference_count
> 0)
622 /* If there's an associated parent value, drop our reference to
624 if (val
->parent
!= NULL
)
625 value_free (val
->parent
);
627 if (VALUE_LVAL (val
) == lval_computed
)
629 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
631 if (funcs
->free_closure
)
632 funcs
->free_closure (val
);
635 xfree (val
->contents
);
640 /* Free all values allocated since MARK was obtained by value_mark
641 (except for those released). */
643 value_free_to_mark (struct value
*mark
)
648 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
656 /* Free all the values that have been allocated (except for those released).
657 Call after each command, successful or not.
658 In practice this is called before each command, which is sufficient. */
661 free_all_values (void)
666 for (val
= all_values
; val
; val
= next
)
675 /* Remove VAL from the chain all_values
676 so it will not be freed automatically. */
679 release_value (struct value
*val
)
683 if (all_values
== val
)
685 all_values
= val
->next
;
689 for (v
= all_values
; v
; v
= v
->next
)
699 /* Release all values up to mark */
701 value_release_to_mark (struct value
*mark
)
706 for (val
= next
= all_values
; next
; next
= next
->next
)
707 if (next
->next
== mark
)
709 all_values
= next
->next
;
717 /* Return a copy of the value ARG.
718 It contains the same contents, for same memory address,
719 but it's a different block of storage. */
722 value_copy (struct value
*arg
)
724 struct type
*encl_type
= value_enclosing_type (arg
);
727 if (value_lazy (arg
))
728 val
= allocate_value_lazy (encl_type
);
730 val
= allocate_value (encl_type
);
731 val
->type
= arg
->type
;
732 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
733 val
->location
= arg
->location
;
734 val
->offset
= arg
->offset
;
735 val
->bitpos
= arg
->bitpos
;
736 val
->bitsize
= arg
->bitsize
;
737 VALUE_FRAME_ID (val
) = VALUE_FRAME_ID (arg
);
738 VALUE_REGNUM (val
) = VALUE_REGNUM (arg
);
739 val
->lazy
= arg
->lazy
;
740 val
->optimized_out
= arg
->optimized_out
;
741 val
->embedded_offset
= value_embedded_offset (arg
);
742 val
->pointed_to_offset
= arg
->pointed_to_offset
;
743 val
->modifiable
= arg
->modifiable
;
744 if (!value_lazy (val
))
746 memcpy (value_contents_all_raw (val
), value_contents_all_raw (arg
),
747 TYPE_LENGTH (value_enclosing_type (arg
)));
750 val
->parent
= arg
->parent
;
752 value_incref (val
->parent
);
753 if (VALUE_LVAL (val
) == lval_computed
)
755 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
757 if (funcs
->copy_closure
)
758 val
->location
.computed
.closure
= funcs
->copy_closure (val
);
764 set_value_component_location (struct value
*component
, struct value
*whole
)
766 if (VALUE_LVAL (whole
) == lval_internalvar
)
767 VALUE_LVAL (component
) = lval_internalvar_component
;
769 VALUE_LVAL (component
) = VALUE_LVAL (whole
);
771 component
->location
= whole
->location
;
772 if (VALUE_LVAL (whole
) == lval_computed
)
774 struct lval_funcs
*funcs
= whole
->location
.computed
.funcs
;
776 if (funcs
->copy_closure
)
777 component
->location
.computed
.closure
= funcs
->copy_closure (whole
);
782 /* Access to the value history. */
784 /* Record a new value in the value history.
785 Returns the absolute history index of the entry.
786 Result of -1 indicates the value was not saved; otherwise it is the
787 value history index of this new item. */
790 record_latest_value (struct value
*val
)
794 /* We don't want this value to have anything to do with the inferior anymore.
795 In particular, "set $1 = 50" should not affect the variable from which
796 the value was taken, and fast watchpoints should be able to assume that
797 a value on the value history never changes. */
798 if (value_lazy (val
))
799 value_fetch_lazy (val
);
800 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
801 from. This is a bit dubious, because then *&$1 does not just return $1
802 but the current contents of that location. c'est la vie... */
806 /* Here we treat value_history_count as origin-zero
807 and applying to the value being stored now. */
809 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
812 struct value_history_chunk
*new
813 = (struct value_history_chunk
*)
814 xmalloc (sizeof (struct value_history_chunk
));
815 memset (new->values
, 0, sizeof new->values
);
816 new->next
= value_history_chain
;
817 value_history_chain
= new;
820 value_history_chain
->values
[i
] = val
;
822 /* Now we regard value_history_count as origin-one
823 and applying to the value just stored. */
825 return ++value_history_count
;
828 /* Return a copy of the value in the history with sequence number NUM. */
831 access_value_history (int num
)
833 struct value_history_chunk
*chunk
;
838 absnum
+= value_history_count
;
843 error (_("The history is empty."));
845 error (_("There is only one value in the history."));
847 error (_("History does not go back to $$%d."), -num
);
849 if (absnum
> value_history_count
)
850 error (_("History has not yet reached $%d."), absnum
);
854 /* Now absnum is always absolute and origin zero. */
856 chunk
= value_history_chain
;
857 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
861 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
865 show_values (char *num_exp
, int from_tty
)
873 /* "show values +" should print from the stored position.
874 "show values <exp>" should print around value number <exp>. */
875 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
876 num
= parse_and_eval_long (num_exp
) - 5;
880 /* "show values" means print the last 10 values. */
881 num
= value_history_count
- 9;
887 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
889 struct value_print_options opts
;
890 val
= access_value_history (i
);
891 printf_filtered (("$%d = "), i
);
892 get_user_print_options (&opts
);
893 value_print (val
, gdb_stdout
, &opts
);
894 printf_filtered (("\n"));
897 /* The next "show values +" should start after what we just printed. */
900 /* Hitting just return after this command should do the same thing as
901 "show values +". If num_exp is null, this is unnecessary, since
902 "show values +" is not useful after "show values". */
903 if (from_tty
&& num_exp
)
910 /* Internal variables. These are variables within the debugger
911 that hold values assigned by debugger commands.
912 The user refers to them with a '$' prefix
913 that does not appear in the variable names stored internally. */
917 struct internalvar
*next
;
920 /* We support various different kinds of content of an internal variable.
921 enum internalvar_kind specifies the kind, and union internalvar_data
922 provides the data associated with this particular kind. */
924 enum internalvar_kind
926 /* The internal variable is empty. */
929 /* The value of the internal variable is provided directly as
930 a GDB value object. */
933 /* A fresh value is computed via a call-back routine on every
934 access to the internal variable. */
935 INTERNALVAR_MAKE_VALUE
,
937 /* The internal variable holds a GDB internal convenience function. */
938 INTERNALVAR_FUNCTION
,
940 /* The variable holds an integer value. */
943 /* The variable holds a pointer value. */
946 /* The variable holds a GDB-provided string. */
951 union internalvar_data
953 /* A value object used with INTERNALVAR_VALUE. */
956 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
957 internalvar_make_value make_value
;
959 /* The internal function used with INTERNALVAR_FUNCTION. */
962 struct internal_function
*function
;
963 /* True if this is the canonical name for the function. */
967 /* An integer value used with INTERNALVAR_INTEGER. */
970 /* If type is non-NULL, it will be used as the type to generate
971 a value for this internal variable. If type is NULL, a default
972 integer type for the architecture is used. */
977 /* A pointer value used with INTERNALVAR_POINTER. */
984 /* A string value used with INTERNALVAR_STRING. */
989 static struct internalvar
*internalvars
;
991 /* If the variable does not already exist create it and give it the value given.
992 If no value is given then the default is zero. */
994 init_if_undefined_command (char* args
, int from_tty
)
996 struct internalvar
* intvar
;
998 /* Parse the expression - this is taken from set_command(). */
999 struct expression
*expr
= parse_expression (args
);
1000 register struct cleanup
*old_chain
=
1001 make_cleanup (free_current_contents
, &expr
);
1003 /* Validate the expression.
1004 Was the expression an assignment?
1005 Or even an expression at all? */
1006 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
1007 error (_("Init-if-undefined requires an assignment expression."));
1009 /* Extract the variable from the parsed expression.
1010 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
1011 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
1012 error (_("The first parameter to init-if-undefined should be a GDB variable."));
1013 intvar
= expr
->elts
[2].internalvar
;
1015 /* Only evaluate the expression if the lvalue is void.
1016 This may still fail if the expresssion is invalid. */
1017 if (intvar
->kind
== INTERNALVAR_VOID
)
1018 evaluate_expression (expr
);
1020 do_cleanups (old_chain
);
1024 /* Look up an internal variable with name NAME. NAME should not
1025 normally include a dollar sign.
1027 If the specified internal variable does not exist,
1028 the return value is NULL. */
1030 struct internalvar
*
1031 lookup_only_internalvar (const char *name
)
1033 struct internalvar
*var
;
1035 for (var
= internalvars
; var
; var
= var
->next
)
1036 if (strcmp (var
->name
, name
) == 0)
1043 /* Create an internal variable with name NAME and with a void value.
1044 NAME should not normally include a dollar sign. */
1046 struct internalvar
*
1047 create_internalvar (const char *name
)
1049 struct internalvar
*var
;
1050 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
1051 var
->name
= concat (name
, (char *)NULL
);
1052 var
->kind
= INTERNALVAR_VOID
;
1053 var
->next
= internalvars
;
1058 /* Create an internal variable with name NAME and register FUN as the
1059 function that value_of_internalvar uses to create a value whenever
1060 this variable is referenced. NAME should not normally include a
1063 struct internalvar
*
1064 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
1066 struct internalvar
*var
= create_internalvar (name
);
1067 var
->kind
= INTERNALVAR_MAKE_VALUE
;
1068 var
->u
.make_value
= fun
;
1072 /* Look up an internal variable with name NAME. NAME should not
1073 normally include a dollar sign.
1075 If the specified internal variable does not exist,
1076 one is created, with a void value. */
1078 struct internalvar
*
1079 lookup_internalvar (const char *name
)
1081 struct internalvar
*var
;
1083 var
= lookup_only_internalvar (name
);
1087 return create_internalvar (name
);
1090 /* Return current value of internal variable VAR. For variables that
1091 are not inherently typed, use a value type appropriate for GDBARCH. */
1094 value_of_internalvar (struct gdbarch
*gdbarch
, struct internalvar
*var
)
1100 case INTERNALVAR_VOID
:
1101 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1104 case INTERNALVAR_FUNCTION
:
1105 val
= allocate_value (builtin_type (gdbarch
)->internal_fn
);
1108 case INTERNALVAR_INTEGER
:
1109 if (!var
->u
.integer
.type
)
1110 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
1111 var
->u
.integer
.val
);
1113 val
= value_from_longest (var
->u
.integer
.type
, var
->u
.integer
.val
);
1116 case INTERNALVAR_POINTER
:
1117 val
= value_from_pointer (var
->u
.pointer
.type
, var
->u
.pointer
.val
);
1120 case INTERNALVAR_STRING
:
1121 val
= value_cstring (var
->u
.string
, strlen (var
->u
.string
),
1122 builtin_type (gdbarch
)->builtin_char
);
1125 case INTERNALVAR_VALUE
:
1126 val
= value_copy (var
->u
.value
);
1127 if (value_lazy (val
))
1128 value_fetch_lazy (val
);
1131 case INTERNALVAR_MAKE_VALUE
:
1132 val
= (*var
->u
.make_value
) (gdbarch
, var
);
1136 internal_error (__FILE__
, __LINE__
, "bad kind");
1139 /* Change the VALUE_LVAL to lval_internalvar so that future operations
1140 on this value go back to affect the original internal variable.
1142 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
1143 no underlying modifyable state in the internal variable.
1145 Likewise, if the variable's value is a computed lvalue, we want
1146 references to it to produce another computed lvalue, where
1147 references and assignments actually operate through the
1148 computed value's functions.
1150 This means that internal variables with computed values
1151 behave a little differently from other internal variables:
1152 assignments to them don't just replace the previous value
1153 altogether. At the moment, this seems like the behavior we
1156 if (var
->kind
!= INTERNALVAR_MAKE_VALUE
1157 && val
->lval
!= lval_computed
)
1159 VALUE_LVAL (val
) = lval_internalvar
;
1160 VALUE_INTERNALVAR (val
) = var
;
1167 get_internalvar_integer (struct internalvar
*var
, LONGEST
*result
)
1171 case INTERNALVAR_INTEGER
:
1172 *result
= var
->u
.integer
.val
;
1181 get_internalvar_function (struct internalvar
*var
,
1182 struct internal_function
**result
)
1186 case INTERNALVAR_FUNCTION
:
1187 *result
= var
->u
.fn
.function
;
1196 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1197 int bitsize
, struct value
*newval
)
1203 case INTERNALVAR_VALUE
:
1204 addr
= value_contents_writeable (var
->u
.value
);
1207 modify_field (value_type (var
->u
.value
), addr
+ offset
,
1208 value_as_long (newval
), bitpos
, bitsize
);
1210 memcpy (addr
+ offset
, value_contents (newval
),
1211 TYPE_LENGTH (value_type (newval
)));
1215 /* We can never get a component of any other kind. */
1216 internal_error (__FILE__
, __LINE__
, "set_internalvar_component");
1221 set_internalvar (struct internalvar
*var
, struct value
*val
)
1223 enum internalvar_kind new_kind
;
1224 union internalvar_data new_data
= { 0 };
1226 if (var
->kind
== INTERNALVAR_FUNCTION
&& var
->u
.fn
.canonical
)
1227 error (_("Cannot overwrite convenience function %s"), var
->name
);
1229 /* Prepare new contents. */
1230 switch (TYPE_CODE (check_typedef (value_type (val
))))
1232 case TYPE_CODE_VOID
:
1233 new_kind
= INTERNALVAR_VOID
;
1236 case TYPE_CODE_INTERNAL_FUNCTION
:
1237 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1238 new_kind
= INTERNALVAR_FUNCTION
;
1239 get_internalvar_function (VALUE_INTERNALVAR (val
),
1240 &new_data
.fn
.function
);
1241 /* Copies created here are never canonical. */
1245 new_kind
= INTERNALVAR_INTEGER
;
1246 new_data
.integer
.type
= value_type (val
);
1247 new_data
.integer
.val
= value_as_long (val
);
1251 new_kind
= INTERNALVAR_POINTER
;
1252 new_data
.pointer
.type
= value_type (val
);
1253 new_data
.pointer
.val
= value_as_address (val
);
1257 new_kind
= INTERNALVAR_VALUE
;
1258 new_data
.value
= value_copy (val
);
1259 new_data
.value
->modifiable
= 1;
1261 /* Force the value to be fetched from the target now, to avoid problems
1262 later when this internalvar is referenced and the target is gone or
1264 if (value_lazy (new_data
.value
))
1265 value_fetch_lazy (new_data
.value
);
1267 /* Release the value from the value chain to prevent it from being
1268 deleted by free_all_values. From here on this function should not
1269 call error () until new_data is installed into the var->u to avoid
1271 release_value (new_data
.value
);
1275 /* Clean up old contents. */
1276 clear_internalvar (var
);
1279 var
->kind
= new_kind
;
1281 /* End code which must not call error(). */
1285 set_internalvar_integer (struct internalvar
*var
, LONGEST l
)
1287 /* Clean up old contents. */
1288 clear_internalvar (var
);
1290 var
->kind
= INTERNALVAR_INTEGER
;
1291 var
->u
.integer
.type
= NULL
;
1292 var
->u
.integer
.val
= l
;
1296 set_internalvar_string (struct internalvar
*var
, const char *string
)
1298 /* Clean up old contents. */
1299 clear_internalvar (var
);
1301 var
->kind
= INTERNALVAR_STRING
;
1302 var
->u
.string
= xstrdup (string
);
1306 set_internalvar_function (struct internalvar
*var
, struct internal_function
*f
)
1308 /* Clean up old contents. */
1309 clear_internalvar (var
);
1311 var
->kind
= INTERNALVAR_FUNCTION
;
1312 var
->u
.fn
.function
= f
;
1313 var
->u
.fn
.canonical
= 1;
1314 /* Variables installed here are always the canonical version. */
1318 clear_internalvar (struct internalvar
*var
)
1320 /* Clean up old contents. */
1323 case INTERNALVAR_VALUE
:
1324 value_free (var
->u
.value
);
1327 case INTERNALVAR_STRING
:
1328 xfree (var
->u
.string
);
1335 /* Reset to void kind. */
1336 var
->kind
= INTERNALVAR_VOID
;
1340 internalvar_name (struct internalvar
*var
)
1345 static struct internal_function
*
1346 create_internal_function (const char *name
,
1347 internal_function_fn handler
, void *cookie
)
1349 struct internal_function
*ifn
= XNEW (struct internal_function
);
1350 ifn
->name
= xstrdup (name
);
1351 ifn
->handler
= handler
;
1352 ifn
->cookie
= cookie
;
1357 value_internal_function_name (struct value
*val
)
1359 struct internal_function
*ifn
;
1362 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1363 result
= get_internalvar_function (VALUE_INTERNALVAR (val
), &ifn
);
1364 gdb_assert (result
);
1370 call_internal_function (struct gdbarch
*gdbarch
,
1371 const struct language_defn
*language
,
1372 struct value
*func
, int argc
, struct value
**argv
)
1374 struct internal_function
*ifn
;
1377 gdb_assert (VALUE_LVAL (func
) == lval_internalvar
);
1378 result
= get_internalvar_function (VALUE_INTERNALVAR (func
), &ifn
);
1379 gdb_assert (result
);
1381 return (*ifn
->handler
) (gdbarch
, language
, ifn
->cookie
, argc
, argv
);
1384 /* The 'function' command. This does nothing -- it is just a
1385 placeholder to let "help function NAME" work. This is also used as
1386 the implementation of the sub-command that is created when
1387 registering an internal function. */
1389 function_command (char *command
, int from_tty
)
1394 /* Clean up if an internal function's command is destroyed. */
1396 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1402 /* Add a new internal function. NAME is the name of the function; DOC
1403 is a documentation string describing the function. HANDLER is
1404 called when the function is invoked. COOKIE is an arbitrary
1405 pointer which is passed to HANDLER and is intended for "user
1408 add_internal_function (const char *name
, const char *doc
,
1409 internal_function_fn handler
, void *cookie
)
1411 struct cmd_list_element
*cmd
;
1412 struct internal_function
*ifn
;
1413 struct internalvar
*var
= lookup_internalvar (name
);
1415 ifn
= create_internal_function (name
, handler
, cookie
);
1416 set_internalvar_function (var
, ifn
);
1418 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1420 cmd
->destroyer
= function_destroyer
;
1423 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1424 prevent cycles / duplicates. */
1427 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1428 htab_t copied_types
)
1430 if (TYPE_OBJFILE (value
->type
) == objfile
)
1431 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1433 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1434 value
->enclosing_type
= copy_type_recursive (objfile
,
1435 value
->enclosing_type
,
1439 /* Likewise for internal variable VAR. */
1442 preserve_one_internalvar (struct internalvar
*var
, struct objfile
*objfile
,
1443 htab_t copied_types
)
1447 case INTERNALVAR_INTEGER
:
1448 if (var
->u
.integer
.type
&& TYPE_OBJFILE (var
->u
.integer
.type
) == objfile
)
1450 = copy_type_recursive (objfile
, var
->u
.integer
.type
, copied_types
);
1453 case INTERNALVAR_POINTER
:
1454 if (TYPE_OBJFILE (var
->u
.pointer
.type
) == objfile
)
1456 = copy_type_recursive (objfile
, var
->u
.pointer
.type
, copied_types
);
1459 case INTERNALVAR_VALUE
:
1460 preserve_one_value (var
->u
.value
, objfile
, copied_types
);
1465 /* Update the internal variables and value history when OBJFILE is
1466 discarded; we must copy the types out of the objfile. New global types
1467 will be created for every convenience variable which currently points to
1468 this objfile's types, and the convenience variables will be adjusted to
1469 use the new global types. */
1472 preserve_values (struct objfile
*objfile
)
1474 htab_t copied_types
;
1475 struct value_history_chunk
*cur
;
1476 struct internalvar
*var
;
1480 /* Create the hash table. We allocate on the objfile's obstack, since
1481 it is soon to be deleted. */
1482 copied_types
= create_copied_types_hash (objfile
);
1484 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1485 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1487 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1489 for (var
= internalvars
; var
; var
= var
->next
)
1490 preserve_one_internalvar (var
, objfile
, copied_types
);
1492 preserve_python_values (objfile
, copied_types
);
1494 htab_delete (copied_types
);
1498 show_convenience (char *ignore
, int from_tty
)
1500 struct gdbarch
*gdbarch
= get_current_arch ();
1501 struct internalvar
*var
;
1503 struct value_print_options opts
;
1505 get_user_print_options (&opts
);
1506 for (var
= internalvars
; var
; var
= var
->next
)
1512 printf_filtered (("$%s = "), var
->name
);
1513 value_print (value_of_internalvar (gdbarch
, var
), gdb_stdout
,
1515 printf_filtered (("\n"));
1518 printf_unfiltered (_("\
1519 No debugger convenience variables now defined.\n\
1520 Convenience variables have names starting with \"$\";\n\
1521 use \"set\" as in \"set $foo = 5\" to define them.\n"));
1524 /* Extract a value as a C number (either long or double).
1525 Knows how to convert fixed values to double, or
1526 floating values to long.
1527 Does not deallocate the value. */
1530 value_as_long (struct value
*val
)
1532 /* This coerces arrays and functions, which is necessary (e.g.
1533 in disassemble_command). It also dereferences references, which
1534 I suspect is the most logical thing to do. */
1535 val
= coerce_array (val
);
1536 return unpack_long (value_type (val
), value_contents (val
));
1540 value_as_double (struct value
*val
)
1545 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1547 error (_("Invalid floating value found in program."));
1551 /* Extract a value as a C pointer. Does not deallocate the value.
1552 Note that val's type may not actually be a pointer; value_as_long
1553 handles all the cases. */
1555 value_as_address (struct value
*val
)
1557 struct gdbarch
*gdbarch
= get_type_arch (value_type (val
));
1559 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1560 whether we want this to be true eventually. */
1562 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1563 non-address (e.g. argument to "signal", "info break", etc.), or
1564 for pointers to char, in which the low bits *are* significant. */
1565 return gdbarch_addr_bits_remove (gdbarch
, value_as_long (val
));
1568 /* There are several targets (IA-64, PowerPC, and others) which
1569 don't represent pointers to functions as simply the address of
1570 the function's entry point. For example, on the IA-64, a
1571 function pointer points to a two-word descriptor, generated by
1572 the linker, which contains the function's entry point, and the
1573 value the IA-64 "global pointer" register should have --- to
1574 support position-independent code. The linker generates
1575 descriptors only for those functions whose addresses are taken.
1577 On such targets, it's difficult for GDB to convert an arbitrary
1578 function address into a function pointer; it has to either find
1579 an existing descriptor for that function, or call malloc and
1580 build its own. On some targets, it is impossible for GDB to
1581 build a descriptor at all: the descriptor must contain a jump
1582 instruction; data memory cannot be executed; and code memory
1585 Upon entry to this function, if VAL is a value of type `function'
1586 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1587 value_address (val) is the address of the function. This is what
1588 you'll get if you evaluate an expression like `main'. The call
1589 to COERCE_ARRAY below actually does all the usual unary
1590 conversions, which includes converting values of type `function'
1591 to `pointer to function'. This is the challenging conversion
1592 discussed above. Then, `unpack_long' will convert that pointer
1593 back into an address.
1595 So, suppose the user types `disassemble foo' on an architecture
1596 with a strange function pointer representation, on which GDB
1597 cannot build its own descriptors, and suppose further that `foo'
1598 has no linker-built descriptor. The address->pointer conversion
1599 will signal an error and prevent the command from running, even
1600 though the next step would have been to convert the pointer
1601 directly back into the same address.
1603 The following shortcut avoids this whole mess. If VAL is a
1604 function, just return its address directly. */
1605 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
1606 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
1607 return value_address (val
);
1609 val
= coerce_array (val
);
1611 /* Some architectures (e.g. Harvard), map instruction and data
1612 addresses onto a single large unified address space. For
1613 instance: An architecture may consider a large integer in the
1614 range 0x10000000 .. 0x1000ffff to already represent a data
1615 addresses (hence not need a pointer to address conversion) while
1616 a small integer would still need to be converted integer to
1617 pointer to address. Just assume such architectures handle all
1618 integer conversions in a single function. */
1622 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1623 must admonish GDB hackers to make sure its behavior matches the
1624 compiler's, whenever possible.
1626 In general, I think GDB should evaluate expressions the same way
1627 the compiler does. When the user copies an expression out of
1628 their source code and hands it to a `print' command, they should
1629 get the same value the compiler would have computed. Any
1630 deviation from this rule can cause major confusion and annoyance,
1631 and needs to be justified carefully. In other words, GDB doesn't
1632 really have the freedom to do these conversions in clever and
1635 AndrewC pointed out that users aren't complaining about how GDB
1636 casts integers to pointers; they are complaining that they can't
1637 take an address from a disassembly listing and give it to `x/i'.
1638 This is certainly important.
1640 Adding an architecture method like integer_to_address() certainly
1641 makes it possible for GDB to "get it right" in all circumstances
1642 --- the target has complete control over how things get done, so
1643 people can Do The Right Thing for their target without breaking
1644 anyone else. The standard doesn't specify how integers get
1645 converted to pointers; usually, the ABI doesn't either, but
1646 ABI-specific code is a more reasonable place to handle it. */
1648 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
1649 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
1650 && gdbarch_integer_to_address_p (gdbarch
))
1651 return gdbarch_integer_to_address (gdbarch
, value_type (val
),
1652 value_contents (val
));
1654 return unpack_long (value_type (val
), value_contents (val
));
1658 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1659 as a long, or as a double, assuming the raw data is described
1660 by type TYPE. Knows how to convert different sizes of values
1661 and can convert between fixed and floating point. We don't assume
1662 any alignment for the raw data. Return value is in host byte order.
1664 If you want functions and arrays to be coerced to pointers, and
1665 references to be dereferenced, call value_as_long() instead.
1667 C++: It is assumed that the front-end has taken care of
1668 all matters concerning pointers to members. A pointer
1669 to member which reaches here is considered to be equivalent
1670 to an INT (or some size). After all, it is only an offset. */
1673 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
1675 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1676 enum type_code code
= TYPE_CODE (type
);
1677 int len
= TYPE_LENGTH (type
);
1678 int nosign
= TYPE_UNSIGNED (type
);
1682 case TYPE_CODE_TYPEDEF
:
1683 return unpack_long (check_typedef (type
), valaddr
);
1684 case TYPE_CODE_ENUM
:
1685 case TYPE_CODE_FLAGS
:
1686 case TYPE_CODE_BOOL
:
1688 case TYPE_CODE_CHAR
:
1689 case TYPE_CODE_RANGE
:
1690 case TYPE_CODE_MEMBERPTR
:
1692 return extract_unsigned_integer (valaddr
, len
, byte_order
);
1694 return extract_signed_integer (valaddr
, len
, byte_order
);
1697 return extract_typed_floating (valaddr
, type
);
1699 case TYPE_CODE_DECFLOAT
:
1700 /* libdecnumber has a function to convert from decimal to integer, but
1701 it doesn't work when the decimal number has a fractional part. */
1702 return decimal_to_doublest (valaddr
, len
, byte_order
);
1706 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1707 whether we want this to be true eventually. */
1708 return extract_typed_address (valaddr
, type
);
1711 error (_("Value can't be converted to integer."));
1713 return 0; /* Placate lint. */
1716 /* Return a double value from the specified type and address.
1717 INVP points to an int which is set to 0 for valid value,
1718 1 for invalid value (bad float format). In either case,
1719 the returned double is OK to use. Argument is in target
1720 format, result is in host format. */
1723 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
1725 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1726 enum type_code code
;
1730 *invp
= 0; /* Assume valid. */
1731 CHECK_TYPEDEF (type
);
1732 code
= TYPE_CODE (type
);
1733 len
= TYPE_LENGTH (type
);
1734 nosign
= TYPE_UNSIGNED (type
);
1735 if (code
== TYPE_CODE_FLT
)
1737 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1738 floating-point value was valid (using the macro
1739 INVALID_FLOAT). That test/macro have been removed.
1741 It turns out that only the VAX defined this macro and then
1742 only in a non-portable way. Fixing the portability problem
1743 wouldn't help since the VAX floating-point code is also badly
1744 bit-rotten. The target needs to add definitions for the
1745 methods gdbarch_float_format and gdbarch_double_format - these
1746 exactly describe the target floating-point format. The
1747 problem here is that the corresponding floatformat_vax_f and
1748 floatformat_vax_d values these methods should be set to are
1749 also not defined either. Oops!
1751 Hopefully someone will add both the missing floatformat
1752 definitions and the new cases for floatformat_is_valid (). */
1754 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
1760 return extract_typed_floating (valaddr
, type
);
1762 else if (code
== TYPE_CODE_DECFLOAT
)
1763 return decimal_to_doublest (valaddr
, len
, byte_order
);
1766 /* Unsigned -- be sure we compensate for signed LONGEST. */
1767 return (ULONGEST
) unpack_long (type
, valaddr
);
1771 /* Signed -- we are OK with unpack_long. */
1772 return unpack_long (type
, valaddr
);
1776 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1777 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1778 We don't assume any alignment for the raw data. Return value is in
1781 If you want functions and arrays to be coerced to pointers, and
1782 references to be dereferenced, call value_as_address() instead.
1784 C++: It is assumed that the front-end has taken care of
1785 all matters concerning pointers to members. A pointer
1786 to member which reaches here is considered to be equivalent
1787 to an INT (or some size). After all, it is only an offset. */
1790 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
1792 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1793 whether we want this to be true eventually. */
1794 return unpack_long (type
, valaddr
);
1798 /* Get the value of the FIELDN'th field (which must be static) of
1799 TYPE. Return NULL if the field doesn't exist or has been
1803 value_static_field (struct type
*type
, int fieldno
)
1805 struct value
*retval
;
1807 if (TYPE_FIELD_LOC_KIND (type
, fieldno
) == FIELD_LOC_KIND_PHYSADDR
)
1809 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1810 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1814 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1815 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1818 /* With some compilers, e.g. HP aCC, static data members are reported
1819 as non-debuggable symbols */
1820 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
, NULL
, NULL
);
1825 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1826 SYMBOL_VALUE_ADDRESS (msym
));
1831 /* SYM should never have a SYMBOL_CLASS which will require
1832 read_var_value to use the FRAME parameter. */
1833 if (symbol_read_needs_frame (sym
))
1834 warning (_("static field's value depends on the current "
1835 "frame - bad debug info?"));
1836 retval
= read_var_value (sym
, NULL
);
1838 if (retval
&& VALUE_LVAL (retval
) == lval_memory
)
1839 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
),
1840 value_address (retval
));
1845 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1846 You have to be careful here, since the size of the data area for the value
1847 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1848 than the old enclosing type, you have to allocate more space for the data.
1849 The return value is a pointer to the new version of this value structure. */
1852 value_change_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
1854 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
1856 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
1858 val
->enclosing_type
= new_encl_type
;
1862 /* Given a value ARG1 (offset by OFFSET bytes)
1863 of a struct or union type ARG_TYPE,
1864 extract and return the value of one of its (non-static) fields.
1865 FIELDNO says which field. */
1868 value_primitive_field (struct value
*arg1
, int offset
,
1869 int fieldno
, struct type
*arg_type
)
1874 CHECK_TYPEDEF (arg_type
);
1875 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
1877 /* Handle packed fields */
1879 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
1881 /* Create a new value for the bitfield, with bitpos and bitsize
1882 set. If possible, arrange offset and bitpos so that we can
1883 do a single aligned read of the size of the containing type.
1884 Otherwise, adjust offset to the byte containing the first
1885 bit. Assume that the address, offset, and embedded offset
1886 are sufficiently aligned. */
1887 int bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
);
1888 int container_bitsize
= TYPE_LENGTH (type
) * 8;
1890 v
= allocate_value_lazy (type
);
1891 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
1892 if ((bitpos
% container_bitsize
) + v
->bitsize
<= container_bitsize
1893 && TYPE_LENGTH (type
) <= (int) sizeof (LONGEST
))
1894 v
->bitpos
= bitpos
% container_bitsize
;
1896 v
->bitpos
= bitpos
% 8;
1897 v
->offset
= value_embedded_offset (arg1
)
1898 + (bitpos
- v
->bitpos
) / 8;
1900 value_incref (v
->parent
);
1901 if (!value_lazy (arg1
))
1902 value_fetch_lazy (v
);
1904 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
1906 /* This field is actually a base subobject, so preserve the
1907 entire object's contents for later references to virtual
1910 /* Lazy register values with offsets are not supported. */
1911 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1912 value_fetch_lazy (arg1
);
1914 if (value_lazy (arg1
))
1915 v
= allocate_value_lazy (value_enclosing_type (arg1
));
1918 v
= allocate_value (value_enclosing_type (arg1
));
1919 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
1920 TYPE_LENGTH (value_enclosing_type (arg1
)));
1923 v
->offset
= value_offset (arg1
);
1924 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
1925 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
1929 /* Plain old data member */
1930 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1932 /* Lazy register values with offsets are not supported. */
1933 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1934 value_fetch_lazy (arg1
);
1936 if (value_lazy (arg1
))
1937 v
= allocate_value_lazy (type
);
1940 v
= allocate_value (type
);
1941 memcpy (value_contents_raw (v
),
1942 value_contents_raw (arg1
) + offset
,
1943 TYPE_LENGTH (type
));
1945 v
->offset
= (value_offset (arg1
) + offset
1946 + value_embedded_offset (arg1
));
1948 set_value_component_location (v
, arg1
);
1949 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
1950 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
1954 /* Given a value ARG1 of a struct or union type,
1955 extract and return the value of one of its (non-static) fields.
1956 FIELDNO says which field. */
1959 value_field (struct value
*arg1
, int fieldno
)
1961 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
1964 /* Return a non-virtual function as a value.
1965 F is the list of member functions which contains the desired method.
1966 J is an index into F which provides the desired method.
1968 We only use the symbol for its address, so be happy with either a
1969 full symbol or a minimal symbol.
1973 value_fn_field (struct value
**arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
1977 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
1978 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
1980 struct minimal_symbol
*msym
;
1982 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
1989 gdb_assert (sym
== NULL
);
1990 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
1995 v
= allocate_value (ftype
);
1998 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
2002 /* The minimal symbol might point to a function descriptor;
2003 resolve it to the actual code address instead. */
2004 struct objfile
*objfile
= msymbol_objfile (msym
);
2005 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
2007 set_value_address (v
,
2008 gdbarch_convert_from_func_ptr_addr
2009 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
2014 if (type
!= value_type (*arg1p
))
2015 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
2016 value_addr (*arg1p
)));
2018 /* Move the `this' pointer according to the offset.
2019 VALUE_OFFSET (*arg1p) += offset;
2027 /* Unpack a bitfield of the specified FIELD_TYPE, from the anonymous
2028 object at VALADDR. The bitfield starts at BITPOS bits and contains
2031 Extracting bits depends on endianness of the machine. Compute the
2032 number of least significant bits to discard. For big endian machines,
2033 we compute the total number of bits in the anonymous object, subtract
2034 off the bit count from the MSB of the object to the MSB of the
2035 bitfield, then the size of the bitfield, which leaves the LSB discard
2036 count. For little endian machines, the discard count is simply the
2037 number of bits from the LSB of the anonymous object to the LSB of the
2040 If the field is signed, we also do sign extension. */
2043 unpack_bits_as_long (struct type
*field_type
, const gdb_byte
*valaddr
,
2044 int bitpos
, int bitsize
)
2046 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (field_type
));
2052 /* Read the minimum number of bytes required; there may not be
2053 enough bytes to read an entire ULONGEST. */
2054 CHECK_TYPEDEF (field_type
);
2056 bytes_read
= ((bitpos
% 8) + bitsize
+ 7) / 8;
2058 bytes_read
= TYPE_LENGTH (field_type
);
2060 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8,
2061 bytes_read
, byte_order
);
2063 /* Extract bits. See comment above. */
2065 if (gdbarch_bits_big_endian (get_type_arch (field_type
)))
2066 lsbcount
= (bytes_read
* 8 - bitpos
% 8 - bitsize
);
2068 lsbcount
= (bitpos
% 8);
2071 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
2072 If the field is signed, and is negative, then sign extend. */
2074 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
2076 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
2078 if (!TYPE_UNSIGNED (field_type
))
2080 if (val
& (valmask
^ (valmask
>> 1)))
2089 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
2090 VALADDR. See unpack_bits_as_long for more details. */
2093 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
2095 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
2096 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
2097 struct type
*field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
2099 return unpack_bits_as_long (field_type
, valaddr
, bitpos
, bitsize
);
2102 /* Modify the value of a bitfield. ADDR points to a block of memory in
2103 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
2104 is the desired value of the field, in host byte order. BITPOS and BITSIZE
2105 indicate which bits (in target bit order) comprise the bitfield.
2106 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS+BITSIZE <= lbits, and
2107 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
2110 modify_field (struct type
*type
, gdb_byte
*addr
,
2111 LONGEST fieldval
, int bitpos
, int bitsize
)
2113 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2115 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
2117 /* If a negative fieldval fits in the field in question, chop
2118 off the sign extension bits. */
2119 if ((~fieldval
& ~(mask
>> 1)) == 0)
2122 /* Warn if value is too big to fit in the field in question. */
2123 if (0 != (fieldval
& ~mask
))
2125 /* FIXME: would like to include fieldval in the message, but
2126 we don't have a sprintf_longest. */
2127 warning (_("Value does not fit in %d bits."), bitsize
);
2129 /* Truncate it, otherwise adjoining fields may be corrupted. */
2133 oword
= extract_unsigned_integer (addr
, sizeof oword
, byte_order
);
2135 /* Shifting for bit field depends on endianness of the target machine. */
2136 if (gdbarch_bits_big_endian (get_type_arch (type
)))
2137 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
2139 oword
&= ~(mask
<< bitpos
);
2140 oword
|= fieldval
<< bitpos
;
2142 store_unsigned_integer (addr
, sizeof oword
, byte_order
, oword
);
2145 /* Pack NUM into BUF using a target format of TYPE. */
2148 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
2150 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2153 type
= check_typedef (type
);
2154 len
= TYPE_LENGTH (type
);
2156 switch (TYPE_CODE (type
))
2159 case TYPE_CODE_CHAR
:
2160 case TYPE_CODE_ENUM
:
2161 case TYPE_CODE_FLAGS
:
2162 case TYPE_CODE_BOOL
:
2163 case TYPE_CODE_RANGE
:
2164 case TYPE_CODE_MEMBERPTR
:
2165 store_signed_integer (buf
, len
, byte_order
, num
);
2170 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2174 error (_("Unexpected type (%d) encountered for integer constant."),
2180 /* Convert C numbers into newly allocated values. */
2183 value_from_longest (struct type
*type
, LONGEST num
)
2185 struct value
*val
= allocate_value (type
);
2187 pack_long (value_contents_raw (val
), type
, num
);
2193 /* Create a value representing a pointer of type TYPE to the address
2196 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
2198 struct value
*val
= allocate_value (type
);
2199 store_typed_address (value_contents_raw (val
), check_typedef (type
), addr
);
2204 /* Create a value of type TYPE whose contents come from VALADDR, if it
2205 is non-null, and whose memory address (in the inferior) is
2209 value_from_contents_and_address (struct type
*type
,
2210 const gdb_byte
*valaddr
,
2213 struct value
*v
= allocate_value (type
);
2214 if (valaddr
== NULL
)
2215 set_value_lazy (v
, 1);
2217 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
2218 set_value_address (v
, address
);
2219 VALUE_LVAL (v
) = lval_memory
;
2224 value_from_double (struct type
*type
, DOUBLEST num
)
2226 struct value
*val
= allocate_value (type
);
2227 struct type
*base_type
= check_typedef (type
);
2228 enum type_code code
= TYPE_CODE (base_type
);
2229 int len
= TYPE_LENGTH (base_type
);
2231 if (code
== TYPE_CODE_FLT
)
2233 store_typed_floating (value_contents_raw (val
), base_type
, num
);
2236 error (_("Unexpected type encountered for floating constant."));
2242 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
2244 struct value
*val
= allocate_value (type
);
2246 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
2252 coerce_ref (struct value
*arg
)
2254 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
2255 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
2256 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
2257 unpack_pointer (value_type (arg
),
2258 value_contents (arg
)));
2263 coerce_array (struct value
*arg
)
2267 arg
= coerce_ref (arg
);
2268 type
= check_typedef (value_type (arg
));
2270 switch (TYPE_CODE (type
))
2272 case TYPE_CODE_ARRAY
:
2273 if (current_language
->c_style_arrays
)
2274 arg
= value_coerce_array (arg
);
2276 case TYPE_CODE_FUNC
:
2277 arg
= value_coerce_function (arg
);
2284 /* Return true if the function returning the specified type is using
2285 the convention of returning structures in memory (passing in the
2286 address as a hidden first parameter). */
2289 using_struct_return (struct gdbarch
*gdbarch
,
2290 struct type
*func_type
, struct type
*value_type
)
2292 enum type_code code
= TYPE_CODE (value_type
);
2294 if (code
== TYPE_CODE_ERROR
)
2295 error (_("Function return type unknown."));
2297 if (code
== TYPE_CODE_VOID
)
2298 /* A void return value is never in memory. See also corresponding
2299 code in "print_return_value". */
2302 /* Probe the architecture for the return-value convention. */
2303 return (gdbarch_return_value (gdbarch
, func_type
, value_type
,
2305 != RETURN_VALUE_REGISTER_CONVENTION
);
2308 /* Set the initialized field in a value struct. */
2311 set_value_initialized (struct value
*val
, int status
)
2313 val
->initialized
= status
;
2316 /* Return the initialized field in a value struct. */
2319 value_initialized (struct value
*val
)
2321 return val
->initialized
;
2325 _initialize_values (void)
2327 add_cmd ("convenience", no_class
, show_convenience
, _("\
2328 Debugger convenience (\"$foo\") variables.\n\
2329 These variables are created when you assign them values;\n\
2330 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2332 A few convenience variables are given values automatically:\n\
2333 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2334 \"$__\" holds the contents of the last address examined with \"x\"."),
2337 add_cmd ("values", no_class
, show_values
,
2338 _("Elements of value history around item number IDX (or last ten)."),
2341 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2342 Initialize a convenience variable if necessary.\n\
2343 init-if-undefined VARIABLE = EXPRESSION\n\
2344 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2345 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2346 VARIABLE is already initialized."));
2348 add_prefix_cmd ("function", no_class
, function_command
, _("\
2349 Placeholder command for showing help on convenience functions."),
2350 &functionlist
, "function ", 0, &cmdlist
);