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 /* Actual contents of the value. Target byte-order. NULL or not
200 valid if lazy is nonzero. */
203 /* The number of references to this value. When a value is created,
204 the value chain holds a reference, so REFERENCE_COUNT is 1. If
205 release_value is called, this value is removed from the chain but
206 the caller of release_value now has a reference to this value.
207 The caller must arrange for a call to value_free later. */
211 /* Prototypes for local functions. */
213 static void show_values (char *, int);
215 static void show_convenience (char *, int);
218 /* The value-history records all the values printed
219 by print commands during this session. Each chunk
220 records 60 consecutive values. The first chunk on
221 the chain records the most recent values.
222 The total number of values is in value_history_count. */
224 #define VALUE_HISTORY_CHUNK 60
226 struct value_history_chunk
228 struct value_history_chunk
*next
;
229 struct value
*values
[VALUE_HISTORY_CHUNK
];
232 /* Chain of chunks now in use. */
234 static struct value_history_chunk
*value_history_chain
;
236 static int value_history_count
; /* Abs number of last entry stored */
239 /* List of all value objects currently allocated
240 (except for those released by calls to release_value)
241 This is so they can be freed after each command. */
243 static struct value
*all_values
;
245 /* Allocate a lazy value for type TYPE. Its actual content is
246 "lazily" allocated too: the content field of the return value is
247 NULL; it will be allocated when it is fetched from the target. */
250 allocate_value_lazy (struct type
*type
)
253 struct type
*atype
= check_typedef (type
);
255 val
= (struct value
*) xzalloc (sizeof (struct value
));
256 val
->contents
= NULL
;
257 val
->next
= all_values
;
260 val
->enclosing_type
= type
;
261 VALUE_LVAL (val
) = not_lval
;
262 val
->location
.address
= 0;
263 VALUE_FRAME_ID (val
) = null_frame_id
;
267 VALUE_REGNUM (val
) = -1;
269 val
->optimized_out
= 0;
270 val
->embedded_offset
= 0;
271 val
->pointed_to_offset
= 0;
273 val
->initialized
= 1; /* Default to initialized. */
275 /* Values start out on the all_values chain. */
276 val
->reference_count
= 1;
281 /* Allocate the contents of VAL if it has not been allocated yet. */
284 allocate_value_contents (struct value
*val
)
287 val
->contents
= (gdb_byte
*) xzalloc (TYPE_LENGTH (val
->enclosing_type
));
290 /* Allocate a value and its contents for type TYPE. */
293 allocate_value (struct type
*type
)
295 struct value
*val
= allocate_value_lazy (type
);
296 allocate_value_contents (val
);
301 /* Allocate a value that has the correct length
302 for COUNT repetitions of type TYPE. */
305 allocate_repeat_value (struct type
*type
, int count
)
307 int low_bound
= current_language
->string_lower_bound
; /* ??? */
308 /* FIXME-type-allocation: need a way to free this type when we are
310 struct type
*array_type
311 = lookup_array_range_type (type
, low_bound
, count
+ low_bound
- 1);
312 return allocate_value (array_type
);
315 /* Needed if another module needs to maintain its on list of values. */
317 value_prepend_to_list (struct value
**head
, struct value
*val
)
323 /* Needed if another module needs to maintain its on list of values. */
325 value_remove_from_list (struct value
**head
, struct value
*val
)
330 *head
= (*head
)->next
;
332 for (prev
= *head
; prev
->next
; prev
= prev
->next
)
333 if (prev
->next
== val
)
335 prev
->next
= val
->next
;
341 allocate_computed_value (struct type
*type
,
342 struct lval_funcs
*funcs
,
345 struct value
*v
= allocate_value (type
);
346 VALUE_LVAL (v
) = lval_computed
;
347 v
->location
.computed
.funcs
= funcs
;
348 v
->location
.computed
.closure
= closure
;
349 set_value_lazy (v
, 1);
354 /* Accessor methods. */
357 value_next (struct value
*value
)
363 value_type (struct value
*value
)
368 deprecated_set_value_type (struct value
*value
, struct type
*type
)
374 value_offset (struct value
*value
)
376 return value
->offset
;
379 set_value_offset (struct value
*value
, int offset
)
381 value
->offset
= offset
;
385 value_bitpos (struct value
*value
)
387 return value
->bitpos
;
390 set_value_bitpos (struct value
*value
, int bit
)
396 value_bitsize (struct value
*value
)
398 return value
->bitsize
;
401 set_value_bitsize (struct value
*value
, int bit
)
403 value
->bitsize
= bit
;
407 value_parent (struct value
*value
)
409 return value
->parent
;
413 value_contents_raw (struct value
*value
)
415 allocate_value_contents (value
);
416 return value
->contents
+ value
->embedded_offset
;
420 value_contents_all_raw (struct value
*value
)
422 allocate_value_contents (value
);
423 return value
->contents
;
427 value_enclosing_type (struct value
*value
)
429 return value
->enclosing_type
;
433 value_contents_all (struct value
*value
)
436 value_fetch_lazy (value
);
437 return value
->contents
;
441 value_lazy (struct value
*value
)
447 set_value_lazy (struct value
*value
, int val
)
453 value_contents (struct value
*value
)
455 return value_contents_writeable (value
);
459 value_contents_writeable (struct value
*value
)
462 value_fetch_lazy (value
);
463 return value_contents_raw (value
);
466 /* Return non-zero if VAL1 and VAL2 have the same contents. Note that
467 this function is different from value_equal; in C the operator ==
468 can return 0 even if the two values being compared are equal. */
471 value_contents_equal (struct value
*val1
, struct value
*val2
)
477 type1
= check_typedef (value_type (val1
));
478 type2
= check_typedef (value_type (val2
));
479 len
= TYPE_LENGTH (type1
);
480 if (len
!= TYPE_LENGTH (type2
))
483 return (memcmp (value_contents (val1
), value_contents (val2
), len
) == 0);
487 value_optimized_out (struct value
*value
)
489 return value
->optimized_out
;
493 set_value_optimized_out (struct value
*value
, int val
)
495 value
->optimized_out
= val
;
499 value_embedded_offset (struct value
*value
)
501 return value
->embedded_offset
;
505 set_value_embedded_offset (struct value
*value
, int val
)
507 value
->embedded_offset
= val
;
511 value_pointed_to_offset (struct value
*value
)
513 return value
->pointed_to_offset
;
517 set_value_pointed_to_offset (struct value
*value
, int val
)
519 value
->pointed_to_offset
= val
;
523 value_computed_funcs (struct value
*v
)
525 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
527 return v
->location
.computed
.funcs
;
531 value_computed_closure (struct value
*v
)
533 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
535 return v
->location
.computed
.closure
;
539 deprecated_value_lval_hack (struct value
*value
)
545 value_address (struct value
*value
)
547 if (value
->lval
== lval_internalvar
548 || value
->lval
== lval_internalvar_component
)
550 return value
->location
.address
+ value
->offset
;
554 value_raw_address (struct value
*value
)
556 if (value
->lval
== lval_internalvar
557 || value
->lval
== lval_internalvar_component
)
559 return value
->location
.address
;
563 set_value_address (struct value
*value
, CORE_ADDR addr
)
565 gdb_assert (value
->lval
!= lval_internalvar
566 && value
->lval
!= lval_internalvar_component
);
567 value
->location
.address
= addr
;
570 struct internalvar
**
571 deprecated_value_internalvar_hack (struct value
*value
)
573 return &value
->location
.internalvar
;
577 deprecated_value_frame_id_hack (struct value
*value
)
579 return &value
->frame_id
;
583 deprecated_value_regnum_hack (struct value
*value
)
585 return &value
->regnum
;
589 deprecated_value_modifiable (struct value
*value
)
591 return value
->modifiable
;
594 deprecated_set_value_modifiable (struct value
*value
, int modifiable
)
596 value
->modifiable
= modifiable
;
599 /* Return a mark in the value chain. All values allocated after the
600 mark is obtained (except for those released) are subject to being freed
601 if a subsequent value_free_to_mark is passed the mark. */
608 /* Take a reference to VAL. VAL will not be deallocated until all
609 references are released. */
612 value_incref (struct value
*val
)
614 val
->reference_count
++;
617 /* Release a reference to VAL, which was acquired with value_incref.
618 This function is also called to deallocate values from the value
622 value_free (struct value
*val
)
626 gdb_assert (val
->reference_count
> 0);
627 val
->reference_count
--;
628 if (val
->reference_count
> 0)
631 /* If there's an associated parent value, drop our reference to
633 if (val
->parent
!= NULL
)
634 value_free (val
->parent
);
636 if (VALUE_LVAL (val
) == lval_computed
)
638 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
640 if (funcs
->free_closure
)
641 funcs
->free_closure (val
);
644 xfree (val
->contents
);
649 /* Free all values allocated since MARK was obtained by value_mark
650 (except for those released). */
652 value_free_to_mark (struct value
*mark
)
657 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
665 /* Free all the values that have been allocated (except for those released).
666 Called after each command, successful or not. */
669 free_all_values (void)
674 for (val
= all_values
; val
; val
= next
)
683 /* Remove VAL from the chain all_values
684 so it will not be freed automatically. */
687 release_value (struct value
*val
)
691 if (all_values
== val
)
693 all_values
= val
->next
;
697 for (v
= all_values
; v
; v
= v
->next
)
707 /* Release all values up to mark */
709 value_release_to_mark (struct value
*mark
)
714 for (val
= next
= all_values
; next
; next
= next
->next
)
715 if (next
->next
== mark
)
717 all_values
= next
->next
;
725 /* Return a copy of the value ARG.
726 It contains the same contents, for same memory address,
727 but it's a different block of storage. */
730 value_copy (struct value
*arg
)
732 struct type
*encl_type
= value_enclosing_type (arg
);
735 if (value_lazy (arg
))
736 val
= allocate_value_lazy (encl_type
);
738 val
= allocate_value (encl_type
);
739 val
->type
= arg
->type
;
740 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
741 val
->location
= arg
->location
;
742 val
->offset
= arg
->offset
;
743 val
->bitpos
= arg
->bitpos
;
744 val
->bitsize
= arg
->bitsize
;
745 VALUE_FRAME_ID (val
) = VALUE_FRAME_ID (arg
);
746 VALUE_REGNUM (val
) = VALUE_REGNUM (arg
);
747 val
->lazy
= arg
->lazy
;
748 val
->optimized_out
= arg
->optimized_out
;
749 val
->embedded_offset
= value_embedded_offset (arg
);
750 val
->pointed_to_offset
= arg
->pointed_to_offset
;
751 val
->modifiable
= arg
->modifiable
;
752 if (!value_lazy (val
))
754 memcpy (value_contents_all_raw (val
), value_contents_all_raw (arg
),
755 TYPE_LENGTH (value_enclosing_type (arg
)));
758 val
->parent
= arg
->parent
;
760 value_incref (val
->parent
);
761 if (VALUE_LVAL (val
) == lval_computed
)
763 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
765 if (funcs
->copy_closure
)
766 val
->location
.computed
.closure
= funcs
->copy_closure (val
);
772 set_value_component_location (struct value
*component
, struct value
*whole
)
774 if (VALUE_LVAL (whole
) == lval_internalvar
)
775 VALUE_LVAL (component
) = lval_internalvar_component
;
777 VALUE_LVAL (component
) = VALUE_LVAL (whole
);
779 component
->location
= whole
->location
;
780 if (VALUE_LVAL (whole
) == lval_computed
)
782 struct lval_funcs
*funcs
= whole
->location
.computed
.funcs
;
784 if (funcs
->copy_closure
)
785 component
->location
.computed
.closure
= funcs
->copy_closure (whole
);
790 /* Access to the value history. */
792 /* Record a new value in the value history.
793 Returns the absolute history index of the entry.
794 Result of -1 indicates the value was not saved; otherwise it is the
795 value history index of this new item. */
798 record_latest_value (struct value
*val
)
802 /* We don't want this value to have anything to do with the inferior anymore.
803 In particular, "set $1 = 50" should not affect the variable from which
804 the value was taken, and fast watchpoints should be able to assume that
805 a value on the value history never changes. */
806 if (value_lazy (val
))
807 value_fetch_lazy (val
);
808 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
809 from. This is a bit dubious, because then *&$1 does not just return $1
810 but the current contents of that location. c'est la vie... */
814 /* Here we treat value_history_count as origin-zero
815 and applying to the value being stored now. */
817 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
820 struct value_history_chunk
*new
821 = (struct value_history_chunk
*)
822 xmalloc (sizeof (struct value_history_chunk
));
823 memset (new->values
, 0, sizeof new->values
);
824 new->next
= value_history_chain
;
825 value_history_chain
= new;
828 value_history_chain
->values
[i
] = val
;
830 /* Now we regard value_history_count as origin-one
831 and applying to the value just stored. */
833 return ++value_history_count
;
836 /* Return a copy of the value in the history with sequence number NUM. */
839 access_value_history (int num
)
841 struct value_history_chunk
*chunk
;
846 absnum
+= value_history_count
;
851 error (_("The history is empty."));
853 error (_("There is only one value in the history."));
855 error (_("History does not go back to $$%d."), -num
);
857 if (absnum
> value_history_count
)
858 error (_("History has not yet reached $%d."), absnum
);
862 /* Now absnum is always absolute and origin zero. */
864 chunk
= value_history_chain
;
865 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
869 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
873 show_values (char *num_exp
, int from_tty
)
881 /* "show values +" should print from the stored position.
882 "show values <exp>" should print around value number <exp>. */
883 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
884 num
= parse_and_eval_long (num_exp
) - 5;
888 /* "show values" means print the last 10 values. */
889 num
= value_history_count
- 9;
895 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
897 struct value_print_options opts
;
898 val
= access_value_history (i
);
899 printf_filtered (("$%d = "), i
);
900 get_user_print_options (&opts
);
901 value_print (val
, gdb_stdout
, &opts
);
902 printf_filtered (("\n"));
905 /* The next "show values +" should start after what we just printed. */
908 /* Hitting just return after this command should do the same thing as
909 "show values +". If num_exp is null, this is unnecessary, since
910 "show values +" is not useful after "show values". */
911 if (from_tty
&& num_exp
)
918 /* Internal variables. These are variables within the debugger
919 that hold values assigned by debugger commands.
920 The user refers to them with a '$' prefix
921 that does not appear in the variable names stored internally. */
925 struct internalvar
*next
;
928 /* We support various different kinds of content of an internal variable.
929 enum internalvar_kind specifies the kind, and union internalvar_data
930 provides the data associated with this particular kind. */
932 enum internalvar_kind
934 /* The internal variable is empty. */
937 /* The value of the internal variable is provided directly as
938 a GDB value object. */
941 /* A fresh value is computed via a call-back routine on every
942 access to the internal variable. */
943 INTERNALVAR_MAKE_VALUE
,
945 /* The internal variable holds a GDB internal convenience function. */
946 INTERNALVAR_FUNCTION
,
948 /* The variable holds a simple scalar value. */
951 /* The variable holds a GDB-provided string. */
956 union internalvar_data
958 /* A value object used with INTERNALVAR_VALUE. */
961 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
962 internalvar_make_value make_value
;
964 /* The internal function used with INTERNALVAR_FUNCTION. */
967 struct internal_function
*function
;
968 /* True if this is the canonical name for the function. */
972 /* A scalar value used with INTERNALVAR_SCALAR. */
975 /* If type is non-NULL, it will be used as the type to generate
976 a value for this internal variable. If type is NULL, a default
977 integer type for the architecture is used. */
981 LONGEST l
; /* Used with TYPE_CODE_INT and NULL types. */
982 CORE_ADDR a
; /* Used with TYPE_CODE_PTR types. */
986 /* A string value used with INTERNALVAR_STRING. */
991 static struct internalvar
*internalvars
;
993 /* If the variable does not already exist create it and give it the value given.
994 If no value is given then the default is zero. */
996 init_if_undefined_command (char* args
, int from_tty
)
998 struct internalvar
* intvar
;
1000 /* Parse the expression - this is taken from set_command(). */
1001 struct expression
*expr
= parse_expression (args
);
1002 register struct cleanup
*old_chain
=
1003 make_cleanup (free_current_contents
, &expr
);
1005 /* Validate the expression.
1006 Was the expression an assignment?
1007 Or even an expression at all? */
1008 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
1009 error (_("Init-if-undefined requires an assignment expression."));
1011 /* Extract the variable from the parsed expression.
1012 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
1013 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
1014 error (_("The first parameter to init-if-undefined should be a GDB variable."));
1015 intvar
= expr
->elts
[2].internalvar
;
1017 /* Only evaluate the expression if the lvalue is void.
1018 This may still fail if the expresssion is invalid. */
1019 if (intvar
->kind
== INTERNALVAR_VOID
)
1020 evaluate_expression (expr
);
1022 do_cleanups (old_chain
);
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 the return value is NULL. */
1032 struct internalvar
*
1033 lookup_only_internalvar (const char *name
)
1035 struct internalvar
*var
;
1037 for (var
= internalvars
; var
; var
= var
->next
)
1038 if (strcmp (var
->name
, name
) == 0)
1045 /* Create an internal variable with name NAME and with a void value.
1046 NAME should not normally include a dollar sign. */
1048 struct internalvar
*
1049 create_internalvar (const char *name
)
1051 struct internalvar
*var
;
1052 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
1053 var
->name
= concat (name
, (char *)NULL
);
1054 var
->kind
= INTERNALVAR_VOID
;
1055 var
->next
= internalvars
;
1060 /* Create an internal variable with name NAME and register FUN as the
1061 function that value_of_internalvar uses to create a value whenever
1062 this variable is referenced. NAME should not normally include a
1065 struct internalvar
*
1066 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
1068 struct internalvar
*var
= create_internalvar (name
);
1069 var
->kind
= INTERNALVAR_MAKE_VALUE
;
1070 var
->u
.make_value
= fun
;
1074 /* Look up an internal variable with name NAME. NAME should not
1075 normally include a dollar sign.
1077 If the specified internal variable does not exist,
1078 one is created, with a void value. */
1080 struct internalvar
*
1081 lookup_internalvar (const char *name
)
1083 struct internalvar
*var
;
1085 var
= lookup_only_internalvar (name
);
1089 return create_internalvar (name
);
1092 /* Return current value of internal variable VAR. For variables that
1093 are not inherently typed, use a value type appropriate for GDBARCH. */
1096 value_of_internalvar (struct gdbarch
*gdbarch
, struct internalvar
*var
)
1102 case INTERNALVAR_VOID
:
1103 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1106 case INTERNALVAR_FUNCTION
:
1107 val
= allocate_value (builtin_type (gdbarch
)->internal_fn
);
1110 case INTERNALVAR_SCALAR
:
1111 if (!var
->u
.scalar
.type
)
1112 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
1113 var
->u
.scalar
.val
.l
);
1114 else if (TYPE_CODE (var
->u
.scalar
.type
) == TYPE_CODE_INT
)
1115 val
= value_from_longest (var
->u
.scalar
.type
, var
->u
.scalar
.val
.l
);
1116 else if (TYPE_CODE (var
->u
.scalar
.type
) == TYPE_CODE_PTR
)
1117 val
= value_from_pointer (var
->u
.scalar
.type
, var
->u
.scalar
.val
.a
);
1119 internal_error (__FILE__
, __LINE__
, "bad type");
1122 case INTERNALVAR_STRING
:
1123 val
= value_cstring (var
->u
.string
, strlen (var
->u
.string
),
1124 builtin_type (gdbarch
)->builtin_char
);
1127 case INTERNALVAR_VALUE
:
1128 val
= value_copy (var
->u
.value
);
1129 if (value_lazy (val
))
1130 value_fetch_lazy (val
);
1133 case INTERNALVAR_MAKE_VALUE
:
1134 val
= (*var
->u
.make_value
) (gdbarch
, var
);
1138 internal_error (__FILE__
, __LINE__
, "bad kind");
1141 /* Change the VALUE_LVAL to lval_internalvar so that future operations
1142 on this value go back to affect the original internal variable.
1144 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
1145 no underlying modifyable state in the internal variable.
1147 Likewise, if the variable's value is a computed lvalue, we want
1148 references to it to produce another computed lvalue, where
1149 references and assignments actually operate through the
1150 computed value's functions.
1152 This means that internal variables with computed values
1153 behave a little differently from other internal variables:
1154 assignments to them don't just replace the previous value
1155 altogether. At the moment, this seems like the behavior we
1158 if (var
->kind
!= INTERNALVAR_MAKE_VALUE
1159 && val
->lval
!= lval_computed
)
1161 VALUE_LVAL (val
) = lval_internalvar
;
1162 VALUE_INTERNALVAR (val
) = var
;
1169 get_internalvar_integer (struct internalvar
*var
, LONGEST
*result
)
1173 case INTERNALVAR_SCALAR
:
1174 if (var
->u
.scalar
.type
== NULL
1175 || TYPE_CODE (var
->u
.scalar
.type
) == TYPE_CODE_INT
)
1177 *result
= var
->u
.scalar
.val
.l
;
1188 get_internalvar_function (struct internalvar
*var
,
1189 struct internal_function
**result
)
1193 case INTERNALVAR_FUNCTION
:
1194 *result
= var
->u
.fn
.function
;
1203 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1204 int bitsize
, struct value
*newval
)
1210 case INTERNALVAR_VALUE
:
1211 addr
= value_contents_writeable (var
->u
.value
);
1214 modify_field (value_type (var
->u
.value
), addr
+ offset
,
1215 value_as_long (newval
), bitpos
, bitsize
);
1217 memcpy (addr
+ offset
, value_contents (newval
),
1218 TYPE_LENGTH (value_type (newval
)));
1222 /* We can never get a component of any other kind. */
1223 internal_error (__FILE__
, __LINE__
, "set_internalvar_component");
1228 set_internalvar (struct internalvar
*var
, struct value
*val
)
1230 enum internalvar_kind new_kind
;
1231 union internalvar_data new_data
= { 0 };
1233 if (var
->kind
== INTERNALVAR_FUNCTION
&& var
->u
.fn
.canonical
)
1234 error (_("Cannot overwrite convenience function %s"), var
->name
);
1236 /* Prepare new contents. */
1237 switch (TYPE_CODE (check_typedef (value_type (val
))))
1239 case TYPE_CODE_VOID
:
1240 new_kind
= INTERNALVAR_VOID
;
1243 case TYPE_CODE_INTERNAL_FUNCTION
:
1244 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1245 new_kind
= INTERNALVAR_FUNCTION
;
1246 get_internalvar_function (VALUE_INTERNALVAR (val
),
1247 &new_data
.fn
.function
);
1248 /* Copies created here are never canonical. */
1252 new_kind
= INTERNALVAR_SCALAR
;
1253 new_data
.scalar
.type
= value_type (val
);
1254 new_data
.scalar
.val
.l
= value_as_long (val
);
1258 new_kind
= INTERNALVAR_SCALAR
;
1259 new_data
.scalar
.type
= value_type (val
);
1260 new_data
.scalar
.val
.a
= value_as_address (val
);
1264 new_kind
= INTERNALVAR_VALUE
;
1265 new_data
.value
= value_copy (val
);
1266 new_data
.value
->modifiable
= 1;
1268 /* Force the value to be fetched from the target now, to avoid problems
1269 later when this internalvar is referenced and the target is gone or
1271 if (value_lazy (new_data
.value
))
1272 value_fetch_lazy (new_data
.value
);
1274 /* Release the value from the value chain to prevent it from being
1275 deleted by free_all_values. From here on this function should not
1276 call error () until new_data is installed into the var->u to avoid
1278 release_value (new_data
.value
);
1282 /* Clean up old contents. */
1283 clear_internalvar (var
);
1286 var
->kind
= new_kind
;
1288 /* End code which must not call error(). */
1292 set_internalvar_integer (struct internalvar
*var
, LONGEST l
)
1294 /* Clean up old contents. */
1295 clear_internalvar (var
);
1297 var
->kind
= INTERNALVAR_SCALAR
;
1298 var
->u
.scalar
.type
= NULL
;
1299 var
->u
.scalar
.val
.l
= l
;
1303 set_internalvar_string (struct internalvar
*var
, const char *string
)
1305 /* Clean up old contents. */
1306 clear_internalvar (var
);
1308 var
->kind
= INTERNALVAR_STRING
;
1309 var
->u
.string
= xstrdup (string
);
1313 set_internalvar_function (struct internalvar
*var
, struct internal_function
*f
)
1315 /* Clean up old contents. */
1316 clear_internalvar (var
);
1318 var
->kind
= INTERNALVAR_FUNCTION
;
1319 var
->u
.fn
.function
= f
;
1320 var
->u
.fn
.canonical
= 1;
1321 /* Variables installed here are always the canonical version. */
1325 clear_internalvar (struct internalvar
*var
)
1327 /* Clean up old contents. */
1330 case INTERNALVAR_VALUE
:
1331 value_free (var
->u
.value
);
1334 case INTERNALVAR_STRING
:
1335 xfree (var
->u
.string
);
1342 /* Reset to void kind. */
1343 var
->kind
= INTERNALVAR_VOID
;
1347 internalvar_name (struct internalvar
*var
)
1352 static struct internal_function
*
1353 create_internal_function (const char *name
,
1354 internal_function_fn handler
, void *cookie
)
1356 struct internal_function
*ifn
= XNEW (struct internal_function
);
1357 ifn
->name
= xstrdup (name
);
1358 ifn
->handler
= handler
;
1359 ifn
->cookie
= cookie
;
1364 value_internal_function_name (struct value
*val
)
1366 struct internal_function
*ifn
;
1369 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1370 result
= get_internalvar_function (VALUE_INTERNALVAR (val
), &ifn
);
1371 gdb_assert (result
);
1377 call_internal_function (struct gdbarch
*gdbarch
,
1378 const struct language_defn
*language
,
1379 struct value
*func
, int argc
, struct value
**argv
)
1381 struct internal_function
*ifn
;
1384 gdb_assert (VALUE_LVAL (func
) == lval_internalvar
);
1385 result
= get_internalvar_function (VALUE_INTERNALVAR (func
), &ifn
);
1386 gdb_assert (result
);
1388 return (*ifn
->handler
) (gdbarch
, language
, ifn
->cookie
, argc
, argv
);
1391 /* The 'function' command. This does nothing -- it is just a
1392 placeholder to let "help function NAME" work. This is also used as
1393 the implementation of the sub-command that is created when
1394 registering an internal function. */
1396 function_command (char *command
, int from_tty
)
1401 /* Clean up if an internal function's command is destroyed. */
1403 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1409 /* Add a new internal function. NAME is the name of the function; DOC
1410 is a documentation string describing the function. HANDLER is
1411 called when the function is invoked. COOKIE is an arbitrary
1412 pointer which is passed to HANDLER and is intended for "user
1415 add_internal_function (const char *name
, const char *doc
,
1416 internal_function_fn handler
, void *cookie
)
1418 struct cmd_list_element
*cmd
;
1419 struct internal_function
*ifn
;
1420 struct internalvar
*var
= lookup_internalvar (name
);
1422 ifn
= create_internal_function (name
, handler
, cookie
);
1423 set_internalvar_function (var
, ifn
);
1425 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1427 cmd
->destroyer
= function_destroyer
;
1430 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1431 prevent cycles / duplicates. */
1434 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1435 htab_t copied_types
)
1437 if (TYPE_OBJFILE (value
->type
) == objfile
)
1438 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1440 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1441 value
->enclosing_type
= copy_type_recursive (objfile
,
1442 value
->enclosing_type
,
1446 /* Likewise for internal variable VAR. */
1449 preserve_one_internalvar (struct internalvar
*var
, struct objfile
*objfile
,
1450 htab_t copied_types
)
1454 case INTERNALVAR_SCALAR
:
1455 if (var
->u
.scalar
.type
&& TYPE_OBJFILE (var
->u
.scalar
.type
) == objfile
)
1457 = copy_type_recursive (objfile
, var
->u
.scalar
.type
, copied_types
);
1460 case INTERNALVAR_VALUE
:
1461 preserve_one_value (var
->u
.value
, objfile
, copied_types
);
1466 /* Update the internal variables and value history when OBJFILE is
1467 discarded; we must copy the types out of the objfile. New global types
1468 will be created for every convenience variable which currently points to
1469 this objfile's types, and the convenience variables will be adjusted to
1470 use the new global types. */
1473 preserve_values (struct objfile
*objfile
)
1475 htab_t copied_types
;
1476 struct value_history_chunk
*cur
;
1477 struct internalvar
*var
;
1481 /* Create the hash table. We allocate on the objfile's obstack, since
1482 it is soon to be deleted. */
1483 copied_types
= create_copied_types_hash (objfile
);
1485 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1486 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1488 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1490 for (var
= internalvars
; var
; var
= var
->next
)
1491 preserve_one_internalvar (var
, objfile
, copied_types
);
1493 for (val
= values_in_python
; val
; val
= val
->next
)
1494 preserve_one_value (val
, objfile
, copied_types
);
1496 htab_delete (copied_types
);
1500 show_convenience (char *ignore
, int from_tty
)
1502 struct gdbarch
*gdbarch
= get_current_arch ();
1503 struct internalvar
*var
;
1505 struct value_print_options opts
;
1507 get_user_print_options (&opts
);
1508 for (var
= internalvars
; var
; var
= var
->next
)
1514 printf_filtered (("$%s = "), var
->name
);
1515 value_print (value_of_internalvar (gdbarch
, var
), gdb_stdout
,
1517 printf_filtered (("\n"));
1520 printf_unfiltered (_("\
1521 No debugger convenience variables now defined.\n\
1522 Convenience variables have names starting with \"$\";\n\
1523 use \"set\" as in \"set $foo = 5\" to define them.\n"));
1526 /* Extract a value as a C number (either long or double).
1527 Knows how to convert fixed values to double, or
1528 floating values to long.
1529 Does not deallocate the value. */
1532 value_as_long (struct value
*val
)
1534 /* This coerces arrays and functions, which is necessary (e.g.
1535 in disassemble_command). It also dereferences references, which
1536 I suspect is the most logical thing to do. */
1537 val
= coerce_array (val
);
1538 return unpack_long (value_type (val
), value_contents (val
));
1542 value_as_double (struct value
*val
)
1547 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1549 error (_("Invalid floating value found in program."));
1553 /* Extract a value as a C pointer. Does not deallocate the value.
1554 Note that val's type may not actually be a pointer; value_as_long
1555 handles all the cases. */
1557 value_as_address (struct value
*val
)
1559 struct gdbarch
*gdbarch
= get_type_arch (value_type (val
));
1561 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1562 whether we want this to be true eventually. */
1564 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1565 non-address (e.g. argument to "signal", "info break", etc.), or
1566 for pointers to char, in which the low bits *are* significant. */
1567 return gdbarch_addr_bits_remove (gdbarch
, value_as_long (val
));
1570 /* There are several targets (IA-64, PowerPC, and others) which
1571 don't represent pointers to functions as simply the address of
1572 the function's entry point. For example, on the IA-64, a
1573 function pointer points to a two-word descriptor, generated by
1574 the linker, which contains the function's entry point, and the
1575 value the IA-64 "global pointer" register should have --- to
1576 support position-independent code. The linker generates
1577 descriptors only for those functions whose addresses are taken.
1579 On such targets, it's difficult for GDB to convert an arbitrary
1580 function address into a function pointer; it has to either find
1581 an existing descriptor for that function, or call malloc and
1582 build its own. On some targets, it is impossible for GDB to
1583 build a descriptor at all: the descriptor must contain a jump
1584 instruction; data memory cannot be executed; and code memory
1587 Upon entry to this function, if VAL is a value of type `function'
1588 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1589 value_address (val) is the address of the function. This is what
1590 you'll get if you evaluate an expression like `main'. The call
1591 to COERCE_ARRAY below actually does all the usual unary
1592 conversions, which includes converting values of type `function'
1593 to `pointer to function'. This is the challenging conversion
1594 discussed above. Then, `unpack_long' will convert that pointer
1595 back into an address.
1597 So, suppose the user types `disassemble foo' on an architecture
1598 with a strange function pointer representation, on which GDB
1599 cannot build its own descriptors, and suppose further that `foo'
1600 has no linker-built descriptor. The address->pointer conversion
1601 will signal an error and prevent the command from running, even
1602 though the next step would have been to convert the pointer
1603 directly back into the same address.
1605 The following shortcut avoids this whole mess. If VAL is a
1606 function, just return its address directly. */
1607 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
1608 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
1609 return value_address (val
);
1611 val
= coerce_array (val
);
1613 /* Some architectures (e.g. Harvard), map instruction and data
1614 addresses onto a single large unified address space. For
1615 instance: An architecture may consider a large integer in the
1616 range 0x10000000 .. 0x1000ffff to already represent a data
1617 addresses (hence not need a pointer to address conversion) while
1618 a small integer would still need to be converted integer to
1619 pointer to address. Just assume such architectures handle all
1620 integer conversions in a single function. */
1624 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1625 must admonish GDB hackers to make sure its behavior matches the
1626 compiler's, whenever possible.
1628 In general, I think GDB should evaluate expressions the same way
1629 the compiler does. When the user copies an expression out of
1630 their source code and hands it to a `print' command, they should
1631 get the same value the compiler would have computed. Any
1632 deviation from this rule can cause major confusion and annoyance,
1633 and needs to be justified carefully. In other words, GDB doesn't
1634 really have the freedom to do these conversions in clever and
1637 AndrewC pointed out that users aren't complaining about how GDB
1638 casts integers to pointers; they are complaining that they can't
1639 take an address from a disassembly listing and give it to `x/i'.
1640 This is certainly important.
1642 Adding an architecture method like integer_to_address() certainly
1643 makes it possible for GDB to "get it right" in all circumstances
1644 --- the target has complete control over how things get done, so
1645 people can Do The Right Thing for their target without breaking
1646 anyone else. The standard doesn't specify how integers get
1647 converted to pointers; usually, the ABI doesn't either, but
1648 ABI-specific code is a more reasonable place to handle it. */
1650 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
1651 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
1652 && gdbarch_integer_to_address_p (gdbarch
))
1653 return gdbarch_integer_to_address (gdbarch
, value_type (val
),
1654 value_contents (val
));
1656 return unpack_long (value_type (val
), value_contents (val
));
1660 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1661 as a long, or as a double, assuming the raw data is described
1662 by type TYPE. Knows how to convert different sizes of values
1663 and can convert between fixed and floating point. We don't assume
1664 any alignment for the raw data. Return value is in host byte order.
1666 If you want functions and arrays to be coerced to pointers, and
1667 references to be dereferenced, call value_as_long() instead.
1669 C++: It is assumed that the front-end has taken care of
1670 all matters concerning pointers to members. A pointer
1671 to member which reaches here is considered to be equivalent
1672 to an INT (or some size). After all, it is only an offset. */
1675 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
1677 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1678 enum type_code code
= TYPE_CODE (type
);
1679 int len
= TYPE_LENGTH (type
);
1680 int nosign
= TYPE_UNSIGNED (type
);
1684 case TYPE_CODE_TYPEDEF
:
1685 return unpack_long (check_typedef (type
), valaddr
);
1686 case TYPE_CODE_ENUM
:
1687 case TYPE_CODE_FLAGS
:
1688 case TYPE_CODE_BOOL
:
1690 case TYPE_CODE_CHAR
:
1691 case TYPE_CODE_RANGE
:
1692 case TYPE_CODE_MEMBERPTR
:
1694 return extract_unsigned_integer (valaddr
, len
, byte_order
);
1696 return extract_signed_integer (valaddr
, len
, byte_order
);
1699 return extract_typed_floating (valaddr
, type
);
1701 case TYPE_CODE_DECFLOAT
:
1702 /* libdecnumber has a function to convert from decimal to integer, but
1703 it doesn't work when the decimal number has a fractional part. */
1704 return decimal_to_doublest (valaddr
, len
, byte_order
);
1708 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1709 whether we want this to be true eventually. */
1710 return extract_typed_address (valaddr
, type
);
1713 error (_("Value can't be converted to integer."));
1715 return 0; /* Placate lint. */
1718 /* Return a double value from the specified type and address.
1719 INVP points to an int which is set to 0 for valid value,
1720 1 for invalid value (bad float format). In either case,
1721 the returned double is OK to use. Argument is in target
1722 format, result is in host format. */
1725 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
1727 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1728 enum type_code code
;
1732 *invp
= 0; /* Assume valid. */
1733 CHECK_TYPEDEF (type
);
1734 code
= TYPE_CODE (type
);
1735 len
= TYPE_LENGTH (type
);
1736 nosign
= TYPE_UNSIGNED (type
);
1737 if (code
== TYPE_CODE_FLT
)
1739 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1740 floating-point value was valid (using the macro
1741 INVALID_FLOAT). That test/macro have been removed.
1743 It turns out that only the VAX defined this macro and then
1744 only in a non-portable way. Fixing the portability problem
1745 wouldn't help since the VAX floating-point code is also badly
1746 bit-rotten. The target needs to add definitions for the
1747 methods gdbarch_float_format and gdbarch_double_format - these
1748 exactly describe the target floating-point format. The
1749 problem here is that the corresponding floatformat_vax_f and
1750 floatformat_vax_d values these methods should be set to are
1751 also not defined either. Oops!
1753 Hopefully someone will add both the missing floatformat
1754 definitions and the new cases for floatformat_is_valid (). */
1756 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
1762 return extract_typed_floating (valaddr
, type
);
1764 else if (code
== TYPE_CODE_DECFLOAT
)
1765 return decimal_to_doublest (valaddr
, len
, byte_order
);
1768 /* Unsigned -- be sure we compensate for signed LONGEST. */
1769 return (ULONGEST
) unpack_long (type
, valaddr
);
1773 /* Signed -- we are OK with unpack_long. */
1774 return unpack_long (type
, valaddr
);
1778 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1779 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1780 We don't assume any alignment for the raw data. Return value is in
1783 If you want functions and arrays to be coerced to pointers, and
1784 references to be dereferenced, call value_as_address() instead.
1786 C++: It is assumed that the front-end has taken care of
1787 all matters concerning pointers to members. A pointer
1788 to member which reaches here is considered to be equivalent
1789 to an INT (or some size). After all, it is only an offset. */
1792 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
1794 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1795 whether we want this to be true eventually. */
1796 return unpack_long (type
, valaddr
);
1800 /* Get the value of the FIELDN'th field (which must be static) of
1801 TYPE. Return NULL if the field doesn't exist or has been
1805 value_static_field (struct type
*type
, int fieldno
)
1807 struct value
*retval
;
1809 if (TYPE_FIELD_LOC_KIND (type
, fieldno
) == FIELD_LOC_KIND_PHYSADDR
)
1811 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1812 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1816 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1817 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1820 /* With some compilers, e.g. HP aCC, static data members are reported
1821 as non-debuggable symbols */
1822 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
, NULL
, NULL
);
1827 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1828 SYMBOL_VALUE_ADDRESS (msym
));
1833 /* SYM should never have a SYMBOL_CLASS which will require
1834 read_var_value to use the FRAME parameter. */
1835 if (symbol_read_needs_frame (sym
))
1836 warning (_("static field's value depends on the current "
1837 "frame - bad debug info?"));
1838 retval
= read_var_value (sym
, NULL
);
1840 if (retval
&& VALUE_LVAL (retval
) == lval_memory
)
1841 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
),
1842 value_address (retval
));
1847 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1848 You have to be careful here, since the size of the data area for the value
1849 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1850 than the old enclosing type, you have to allocate more space for the data.
1851 The return value is a pointer to the new version of this value structure. */
1854 value_change_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
1856 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
1858 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
1860 val
->enclosing_type
= new_encl_type
;
1864 /* Given a value ARG1 (offset by OFFSET bytes)
1865 of a struct or union type ARG_TYPE,
1866 extract and return the value of one of its (non-static) fields.
1867 FIELDNO says which field. */
1870 value_primitive_field (struct value
*arg1
, int offset
,
1871 int fieldno
, struct type
*arg_type
)
1876 CHECK_TYPEDEF (arg_type
);
1877 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
1879 /* Handle packed fields */
1881 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
1883 /* Create a new value for the bitfield, with bitpos and bitsize
1884 set. If possible, arrange offset and bitpos so that we can
1885 do a single aligned read of the size of the containing type.
1886 Otherwise, adjust offset to the byte containing the first
1887 bit. Assume that the address, offset, and embedded offset
1888 are sufficiently aligned. */
1889 int bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
);
1890 int container_bitsize
= TYPE_LENGTH (type
) * 8;
1892 v
= allocate_value_lazy (type
);
1893 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
1894 if ((bitpos
% container_bitsize
) + v
->bitsize
<= container_bitsize
1895 && TYPE_LENGTH (type
) <= (int) sizeof (LONGEST
))
1896 v
->bitpos
= bitpos
% container_bitsize
;
1898 v
->bitpos
= bitpos
% 8;
1899 v
->offset
= value_offset (arg1
) + value_embedded_offset (arg1
)
1900 + (bitpos
- v
->bitpos
) / 8;
1902 value_incref (v
->parent
);
1903 if (!value_lazy (arg1
))
1904 value_fetch_lazy (v
);
1906 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
1908 /* This field is actually a base subobject, so preserve the
1909 entire object's contents for later references to virtual
1912 /* Lazy register values with offsets are not supported. */
1913 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1914 value_fetch_lazy (arg1
);
1916 if (value_lazy (arg1
))
1917 v
= allocate_value_lazy (value_enclosing_type (arg1
));
1920 v
= allocate_value (value_enclosing_type (arg1
));
1921 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
1922 TYPE_LENGTH (value_enclosing_type (arg1
)));
1925 v
->offset
= value_offset (arg1
);
1926 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
1927 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
1931 /* Plain old data member */
1932 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1934 /* Lazy register values with offsets are not supported. */
1935 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1936 value_fetch_lazy (arg1
);
1938 if (value_lazy (arg1
))
1939 v
= allocate_value_lazy (type
);
1942 v
= allocate_value (type
);
1943 memcpy (value_contents_raw (v
),
1944 value_contents_raw (arg1
) + offset
,
1945 TYPE_LENGTH (type
));
1947 v
->offset
= (value_offset (arg1
) + offset
1948 + value_embedded_offset (arg1
));
1950 set_value_component_location (v
, arg1
);
1951 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
1952 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
1956 /* Given a value ARG1 of a struct or union type,
1957 extract and return the value of one of its (non-static) fields.
1958 FIELDNO says which field. */
1961 value_field (struct value
*arg1
, int fieldno
)
1963 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
1966 /* Return a non-virtual function as a value.
1967 F is the list of member functions which contains the desired method.
1968 J is an index into F which provides the desired method.
1970 We only use the symbol for its address, so be happy with either a
1971 full symbol or a minimal symbol.
1975 value_fn_field (struct value
**arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
1979 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
1980 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
1982 struct minimal_symbol
*msym
;
1984 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
1991 gdb_assert (sym
== NULL
);
1992 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
1997 v
= allocate_value (ftype
);
2000 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
2004 /* The minimal symbol might point to a function descriptor;
2005 resolve it to the actual code address instead. */
2006 struct objfile
*objfile
= msymbol_objfile (msym
);
2007 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
2009 set_value_address (v
,
2010 gdbarch_convert_from_func_ptr_addr
2011 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
2016 if (type
!= value_type (*arg1p
))
2017 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
2018 value_addr (*arg1p
)));
2020 /* Move the `this' pointer according to the offset.
2021 VALUE_OFFSET (*arg1p) += offset;
2029 /* Unpack a bitfield of the specified FIELD_TYPE, from the anonymous
2030 object at VALADDR. The bitfield starts at BITPOS bits and contains
2033 Extracting bits depends on endianness of the machine. Compute the
2034 number of least significant bits to discard. For big endian machines,
2035 we compute the total number of bits in the anonymous object, subtract
2036 off the bit count from the MSB of the object to the MSB of the
2037 bitfield, then the size of the bitfield, which leaves the LSB discard
2038 count. For little endian machines, the discard count is simply the
2039 number of bits from the LSB of the anonymous object to the LSB of the
2042 If the field is signed, we also do sign extension. */
2045 unpack_bits_as_long (struct type
*field_type
, const gdb_byte
*valaddr
,
2046 int bitpos
, int bitsize
)
2048 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (field_type
));
2053 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8,
2054 sizeof (val
), byte_order
);
2055 CHECK_TYPEDEF (field_type
);
2057 /* Extract bits. See comment above. */
2059 if (gdbarch_bits_big_endian (get_type_arch (field_type
)))
2060 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
2062 lsbcount
= (bitpos
% 8);
2065 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
2066 If the field is signed, and is negative, then sign extend. */
2068 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
2070 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
2072 if (!TYPE_UNSIGNED (field_type
))
2074 if (val
& (valmask
^ (valmask
>> 1)))
2083 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
2084 VALADDR. See unpack_bits_as_long for more details. */
2087 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
2089 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
2090 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
2091 struct type
*field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
2093 return unpack_bits_as_long (field_type
, valaddr
, bitpos
, bitsize
);
2096 /* Modify the value of a bitfield. ADDR points to a block of memory in
2097 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
2098 is the desired value of the field, in host byte order. BITPOS and BITSIZE
2099 indicate which bits (in target bit order) comprise the bitfield.
2100 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS+BITSIZE <= lbits, and
2101 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
2104 modify_field (struct type
*type
, gdb_byte
*addr
,
2105 LONGEST fieldval
, int bitpos
, int bitsize
)
2107 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2109 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
2111 /* If a negative fieldval fits in the field in question, chop
2112 off the sign extension bits. */
2113 if ((~fieldval
& ~(mask
>> 1)) == 0)
2116 /* Warn if value is too big to fit in the field in question. */
2117 if (0 != (fieldval
& ~mask
))
2119 /* FIXME: would like to include fieldval in the message, but
2120 we don't have a sprintf_longest. */
2121 warning (_("Value does not fit in %d bits."), bitsize
);
2123 /* Truncate it, otherwise adjoining fields may be corrupted. */
2127 oword
= extract_unsigned_integer (addr
, sizeof oword
, byte_order
);
2129 /* Shifting for bit field depends on endianness of the target machine. */
2130 if (gdbarch_bits_big_endian (get_type_arch (type
)))
2131 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
2133 oword
&= ~(mask
<< bitpos
);
2134 oword
|= fieldval
<< bitpos
;
2136 store_unsigned_integer (addr
, sizeof oword
, byte_order
, oword
);
2139 /* Pack NUM into BUF using a target format of TYPE. */
2142 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
2144 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2147 type
= check_typedef (type
);
2148 len
= TYPE_LENGTH (type
);
2150 switch (TYPE_CODE (type
))
2153 case TYPE_CODE_CHAR
:
2154 case TYPE_CODE_ENUM
:
2155 case TYPE_CODE_FLAGS
:
2156 case TYPE_CODE_BOOL
:
2157 case TYPE_CODE_RANGE
:
2158 case TYPE_CODE_MEMBERPTR
:
2159 store_signed_integer (buf
, len
, byte_order
, num
);
2164 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2168 error (_("Unexpected type (%d) encountered for integer constant."),
2174 /* Convert C numbers into newly allocated values. */
2177 value_from_longest (struct type
*type
, LONGEST num
)
2179 struct value
*val
= allocate_value (type
);
2181 pack_long (value_contents_raw (val
), type
, num
);
2187 /* Create a value representing a pointer of type TYPE to the address
2190 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
2192 struct value
*val
= allocate_value (type
);
2193 store_typed_address (value_contents_raw (val
), type
, addr
);
2198 /* Create a value of type TYPE whose contents come from VALADDR, if it
2199 is non-null, and whose memory address (in the inferior) is
2203 value_from_contents_and_address (struct type
*type
,
2204 const gdb_byte
*valaddr
,
2207 struct value
*v
= allocate_value (type
);
2208 if (valaddr
== NULL
)
2209 set_value_lazy (v
, 1);
2211 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
2212 set_value_address (v
, address
);
2213 VALUE_LVAL (v
) = lval_memory
;
2218 value_from_double (struct type
*type
, DOUBLEST num
)
2220 struct value
*val
= allocate_value (type
);
2221 struct type
*base_type
= check_typedef (type
);
2222 enum type_code code
= TYPE_CODE (base_type
);
2223 int len
= TYPE_LENGTH (base_type
);
2225 if (code
== TYPE_CODE_FLT
)
2227 store_typed_floating (value_contents_raw (val
), base_type
, num
);
2230 error (_("Unexpected type encountered for floating constant."));
2236 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
2238 struct value
*val
= allocate_value (type
);
2240 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
2246 coerce_ref (struct value
*arg
)
2248 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
2249 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
2250 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
2251 unpack_pointer (value_type (arg
),
2252 value_contents (arg
)));
2257 coerce_array (struct value
*arg
)
2261 arg
= coerce_ref (arg
);
2262 type
= check_typedef (value_type (arg
));
2264 switch (TYPE_CODE (type
))
2266 case TYPE_CODE_ARRAY
:
2267 if (current_language
->c_style_arrays
)
2268 arg
= value_coerce_array (arg
);
2270 case TYPE_CODE_FUNC
:
2271 arg
= value_coerce_function (arg
);
2278 /* Return true if the function returning the specified type is using
2279 the convention of returning structures in memory (passing in the
2280 address as a hidden first parameter). */
2283 using_struct_return (struct gdbarch
*gdbarch
,
2284 struct type
*func_type
, struct type
*value_type
)
2286 enum type_code code
= TYPE_CODE (value_type
);
2288 if (code
== TYPE_CODE_ERROR
)
2289 error (_("Function return type unknown."));
2291 if (code
== TYPE_CODE_VOID
)
2292 /* A void return value is never in memory. See also corresponding
2293 code in "print_return_value". */
2296 /* Probe the architecture for the return-value convention. */
2297 return (gdbarch_return_value (gdbarch
, func_type
, value_type
,
2299 != RETURN_VALUE_REGISTER_CONVENTION
);
2302 /* Set the initialized field in a value struct. */
2305 set_value_initialized (struct value
*val
, int status
)
2307 val
->initialized
= status
;
2310 /* Return the initialized field in a value struct. */
2313 value_initialized (struct value
*val
)
2315 return val
->initialized
;
2319 _initialize_values (void)
2321 add_cmd ("convenience", no_class
, show_convenience
, _("\
2322 Debugger convenience (\"$foo\") variables.\n\
2323 These variables are created when you assign them values;\n\
2324 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2326 A few convenience variables are given values automatically:\n\
2327 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2328 \"$__\" holds the contents of the last address examined with \"x\"."),
2331 add_cmd ("values", no_class
, show_values
,
2332 _("Elements of value history around item number IDX (or last ten)."),
2335 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2336 Initialize a convenience variable if necessary.\n\
2337 init-if-undefined VARIABLE = EXPRESSION\n\
2338 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2339 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2340 VARIABLE is already initialized."));
2342 add_prefix_cmd ("function", no_class
, function_command
, _("\
2343 Placeholder command for showing help on convenience functions."),
2344 &functionlist
, "function ", 0, &cmdlist
);