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 "gdb_string.h"
34 #include "gdb_assert.h"
40 #include "cli/cli-decode.h"
42 #include "python/python.h"
44 /* Prototypes for exported functions. */
46 void _initialize_values (void);
48 /* Definition of a user function. */
49 struct internal_function
51 /* The name of the function. It is a bit odd to have this in the
52 function itself -- the user might use a differently-named
53 convenience variable to hold the function. */
57 internal_function_fn handler
;
59 /* User data for the handler. */
63 static struct cmd_list_element
*functionlist
;
67 /* Type of value; either not an lval, or one of the various
68 different possible kinds of lval. */
71 /* Is it modifiable? Only relevant if lval != not_lval. */
74 /* Location of value (if lval). */
77 /* If lval == lval_memory, this is the address in the inferior.
78 If lval == lval_register, this is the byte offset into the
79 registers structure. */
82 /* Pointer to internal variable. */
83 struct internalvar
*internalvar
;
85 /* If lval == lval_computed, this is a set of function pointers
86 to use to access and describe the value, and a closure pointer
90 struct lval_funcs
*funcs
; /* Functions to call. */
91 void *closure
; /* Closure for those functions to use. */
95 /* Describes offset of a value within lval of a structure in bytes.
96 If lval == lval_memory, this is an offset to the address. If
97 lval == lval_register, this is a further offset from
98 location.address within the registers structure. Note also the
99 member embedded_offset below. */
102 /* Only used for bitfields; number of bits contained in them. */
105 /* Only used for bitfields; position of start of field. For
106 gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
107 gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
110 /* Frame register value is relative to. This will be described in
111 the lval enum above as "lval_register". */
112 struct frame_id frame_id
;
114 /* Type of the value. */
117 /* If a value represents a C++ object, then the `type' field gives
118 the object's compile-time type. If the object actually belongs
119 to some class derived from `type', perhaps with other base
120 classes and additional members, then `type' is just a subobject
121 of the real thing, and the full object is probably larger than
122 `type' would suggest.
124 If `type' is a dynamic class (i.e. one with a vtable), then GDB
125 can actually determine the object's run-time type by looking at
126 the run-time type information in the vtable. When this
127 information is available, we may elect to read in the entire
128 object, for several reasons:
130 - When printing the value, the user would probably rather see the
131 full object, not just the limited portion apparent from the
134 - If `type' has virtual base classes, then even printing `type'
135 alone may require reaching outside the `type' portion of the
136 object to wherever the virtual base class has been stored.
138 When we store the entire object, `enclosing_type' is the run-time
139 type -- the complete object -- and `embedded_offset' is the
140 offset of `type' within that larger type, in bytes. The
141 value_contents() macro takes `embedded_offset' into account, so
142 most GDB code continues to see the `type' portion of the value,
143 just as the inferior would.
145 If `type' is a pointer to an object, then `enclosing_type' is a
146 pointer to the object's run-time type, and `pointed_to_offset' is
147 the offset in bytes from the full object to the pointed-to object
148 -- that is, the value `embedded_offset' would have if we followed
149 the pointer and fetched the complete object. (I don't really see
150 the point. Why not just determine the run-time type when you
151 indirect, and avoid the special case? The contents don't matter
152 until you indirect anyway.)
154 If we're not doing anything fancy, `enclosing_type' is equal to
155 `type', and `embedded_offset' is zero, so everything works
157 struct type
*enclosing_type
;
159 int pointed_to_offset
;
161 /* Values are stored in a chain, so that they can be deleted easily
162 over calls to the inferior. Values assigned to internal
163 variables, put into the value history or exposed to Python are
164 taken off this list. */
167 /* Register number if the value is from a register. */
170 /* If zero, contents of this value are in the contents field. If
171 nonzero, contents are in inferior. If the lval field is lval_memory,
172 the contents are in inferior memory at location.address plus offset.
173 The lval field may also be lval_register.
175 WARNING: This field is used by the code which handles watchpoints
176 (see breakpoint.c) to decide whether a particular value can be
177 watched by hardware watchpoints. If the lazy flag is set for
178 some member of a value chain, it is assumed that this member of
179 the chain doesn't need to be watched as part of watching the
180 value itself. This is how GDB avoids watching the entire struct
181 or array when the user wants to watch a single struct member or
182 array element. If you ever change the way lazy flag is set and
183 reset, be sure to consider this use as well! */
186 /* If nonzero, this is the value of a variable which does not
187 actually exist in the program. */
190 /* If value is a variable, is it initialized or not. */
193 /* Actual contents of the value. Target byte-order. NULL or not
194 valid if lazy is nonzero. */
198 /* Prototypes for local functions. */
200 static void show_values (char *, int);
202 static void show_convenience (char *, int);
205 /* The value-history records all the values printed
206 by print commands during this session. Each chunk
207 records 60 consecutive values. The first chunk on
208 the chain records the most recent values.
209 The total number of values is in value_history_count. */
211 #define VALUE_HISTORY_CHUNK 60
213 struct value_history_chunk
215 struct value_history_chunk
*next
;
216 struct value
*values
[VALUE_HISTORY_CHUNK
];
219 /* Chain of chunks now in use. */
221 static struct value_history_chunk
*value_history_chain
;
223 static int value_history_count
; /* Abs number of last entry stored */
225 /* The type of internal functions. */
227 static struct type
*internal_fn_type
;
229 /* List of all value objects currently allocated
230 (except for those released by calls to release_value)
231 This is so they can be freed after each command. */
233 static struct value
*all_values
;
235 /* Allocate a lazy value for type TYPE. Its actual content is
236 "lazily" allocated too: the content field of the return value is
237 NULL; it will be allocated when it is fetched from the target. */
240 allocate_value_lazy (struct type
*type
)
243 struct type
*atype
= check_typedef (type
);
245 val
= (struct value
*) xzalloc (sizeof (struct value
));
246 val
->contents
= NULL
;
247 val
->next
= all_values
;
250 val
->enclosing_type
= type
;
251 VALUE_LVAL (val
) = not_lval
;
252 val
->location
.address
= 0;
253 VALUE_FRAME_ID (val
) = null_frame_id
;
257 VALUE_REGNUM (val
) = -1;
259 val
->optimized_out
= 0;
260 val
->embedded_offset
= 0;
261 val
->pointed_to_offset
= 0;
263 val
->initialized
= 1; /* Default to initialized. */
267 /* Allocate the contents of VAL if it has not been allocated yet. */
270 allocate_value_contents (struct value
*val
)
273 val
->contents
= (gdb_byte
*) xzalloc (TYPE_LENGTH (val
->enclosing_type
));
276 /* Allocate a value and its contents for type TYPE. */
279 allocate_value (struct type
*type
)
281 struct value
*val
= allocate_value_lazy (type
);
282 allocate_value_contents (val
);
287 /* Allocate a value that has the correct length
288 for COUNT repetitions of type TYPE. */
291 allocate_repeat_value (struct type
*type
, int count
)
293 int low_bound
= current_language
->string_lower_bound
; /* ??? */
294 /* FIXME-type-allocation: need a way to free this type when we are
296 struct type
*range_type
297 = create_range_type ((struct type
*) NULL
, builtin_type_int32
,
298 low_bound
, count
+ low_bound
- 1);
299 /* FIXME-type-allocation: need a way to free this type when we are
301 return allocate_value (create_array_type ((struct type
*) NULL
,
305 /* Needed if another module needs to maintain its on list of values. */
307 value_prepend_to_list (struct value
**head
, struct value
*val
)
313 /* Needed if another module needs to maintain its on list of values. */
315 value_remove_from_list (struct value
**head
, struct value
*val
)
320 *head
= (*head
)->next
;
322 for (prev
= *head
; prev
->next
; prev
= prev
->next
)
323 if (prev
->next
== val
)
325 prev
->next
= val
->next
;
331 allocate_computed_value (struct type
*type
,
332 struct lval_funcs
*funcs
,
335 struct value
*v
= allocate_value (type
);
336 VALUE_LVAL (v
) = lval_computed
;
337 v
->location
.computed
.funcs
= funcs
;
338 v
->location
.computed
.closure
= closure
;
339 set_value_lazy (v
, 1);
344 /* Accessor methods. */
347 value_next (struct value
*value
)
353 value_type (struct value
*value
)
358 deprecated_set_value_type (struct value
*value
, struct type
*type
)
364 value_offset (struct value
*value
)
366 return value
->offset
;
369 set_value_offset (struct value
*value
, int offset
)
371 value
->offset
= offset
;
375 value_bitpos (struct value
*value
)
377 return value
->bitpos
;
380 set_value_bitpos (struct value
*value
, int bit
)
386 value_bitsize (struct value
*value
)
388 return value
->bitsize
;
391 set_value_bitsize (struct value
*value
, int bit
)
393 value
->bitsize
= bit
;
397 value_contents_raw (struct value
*value
)
399 allocate_value_contents (value
);
400 return value
->contents
+ value
->embedded_offset
;
404 value_contents_all_raw (struct value
*value
)
406 allocate_value_contents (value
);
407 return value
->contents
;
411 value_enclosing_type (struct value
*value
)
413 return value
->enclosing_type
;
417 value_contents_all (struct value
*value
)
420 value_fetch_lazy (value
);
421 return value
->contents
;
425 value_lazy (struct value
*value
)
431 set_value_lazy (struct value
*value
, int val
)
437 value_contents (struct value
*value
)
439 return value_contents_writeable (value
);
443 value_contents_writeable (struct value
*value
)
446 value_fetch_lazy (value
);
447 return value_contents_raw (value
);
450 /* Return non-zero if VAL1 and VAL2 have the same contents. Note that
451 this function is different from value_equal; in C the operator ==
452 can return 0 even if the two values being compared are equal. */
455 value_contents_equal (struct value
*val1
, struct value
*val2
)
461 type1
= check_typedef (value_type (val1
));
462 type2
= check_typedef (value_type (val2
));
463 len
= TYPE_LENGTH (type1
);
464 if (len
!= TYPE_LENGTH (type2
))
467 return (memcmp (value_contents (val1
), value_contents (val2
), len
) == 0);
471 value_optimized_out (struct value
*value
)
473 return value
->optimized_out
;
477 set_value_optimized_out (struct value
*value
, int val
)
479 value
->optimized_out
= val
;
483 value_embedded_offset (struct value
*value
)
485 return value
->embedded_offset
;
489 set_value_embedded_offset (struct value
*value
, int val
)
491 value
->embedded_offset
= val
;
495 value_pointed_to_offset (struct value
*value
)
497 return value
->pointed_to_offset
;
501 set_value_pointed_to_offset (struct value
*value
, int val
)
503 value
->pointed_to_offset
= val
;
507 value_computed_funcs (struct value
*v
)
509 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
511 return v
->location
.computed
.funcs
;
515 value_computed_closure (struct value
*v
)
517 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
519 return v
->location
.computed
.closure
;
523 deprecated_value_lval_hack (struct value
*value
)
529 value_address (struct value
*value
)
531 if (value
->lval
== lval_internalvar
532 || value
->lval
== lval_internalvar_component
)
534 return value
->location
.address
+ value
->offset
;
538 value_raw_address (struct value
*value
)
540 if (value
->lval
== lval_internalvar
541 || value
->lval
== lval_internalvar_component
)
543 return value
->location
.address
;
547 set_value_address (struct value
*value
, CORE_ADDR addr
)
549 gdb_assert (value
->lval
!= lval_internalvar
550 && value
->lval
!= lval_internalvar_component
);
551 value
->location
.address
= addr
;
554 struct internalvar
**
555 deprecated_value_internalvar_hack (struct value
*value
)
557 return &value
->location
.internalvar
;
561 deprecated_value_frame_id_hack (struct value
*value
)
563 return &value
->frame_id
;
567 deprecated_value_regnum_hack (struct value
*value
)
569 return &value
->regnum
;
573 deprecated_value_modifiable (struct value
*value
)
575 return value
->modifiable
;
578 deprecated_set_value_modifiable (struct value
*value
, int modifiable
)
580 value
->modifiable
= modifiable
;
583 /* Return a mark in the value chain. All values allocated after the
584 mark is obtained (except for those released) are subject to being freed
585 if a subsequent value_free_to_mark is passed the mark. */
593 value_free (struct value
*val
)
597 if (VALUE_LVAL (val
) == lval_computed
)
599 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
601 if (funcs
->free_closure
)
602 funcs
->free_closure (val
);
605 xfree (val
->contents
);
610 /* Free all values allocated since MARK was obtained by value_mark
611 (except for those released). */
613 value_free_to_mark (struct value
*mark
)
618 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
626 /* Free all the values that have been allocated (except for those released).
627 Called after each command, successful or not. */
630 free_all_values (void)
635 for (val
= all_values
; val
; val
= next
)
644 /* Remove VAL from the chain all_values
645 so it will not be freed automatically. */
648 release_value (struct value
*val
)
652 if (all_values
== val
)
654 all_values
= val
->next
;
658 for (v
= all_values
; v
; v
= v
->next
)
668 /* Release all values up to mark */
670 value_release_to_mark (struct value
*mark
)
675 for (val
= next
= all_values
; next
; next
= next
->next
)
676 if (next
->next
== mark
)
678 all_values
= next
->next
;
686 /* Return a copy of the value ARG.
687 It contains the same contents, for same memory address,
688 but it's a different block of storage. */
691 value_copy (struct value
*arg
)
693 struct type
*encl_type
= value_enclosing_type (arg
);
696 if (value_lazy (arg
))
697 val
= allocate_value_lazy (encl_type
);
699 val
= allocate_value (encl_type
);
700 val
->type
= arg
->type
;
701 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
702 val
->location
= arg
->location
;
703 val
->offset
= arg
->offset
;
704 val
->bitpos
= arg
->bitpos
;
705 val
->bitsize
= arg
->bitsize
;
706 VALUE_FRAME_ID (val
) = VALUE_FRAME_ID (arg
);
707 VALUE_REGNUM (val
) = VALUE_REGNUM (arg
);
708 val
->lazy
= arg
->lazy
;
709 val
->optimized_out
= arg
->optimized_out
;
710 val
->embedded_offset
= value_embedded_offset (arg
);
711 val
->pointed_to_offset
= arg
->pointed_to_offset
;
712 val
->modifiable
= arg
->modifiable
;
713 if (!value_lazy (val
))
715 memcpy (value_contents_all_raw (val
), value_contents_all_raw (arg
),
716 TYPE_LENGTH (value_enclosing_type (arg
)));
719 if (VALUE_LVAL (val
) == lval_computed
)
721 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
723 if (funcs
->copy_closure
)
724 val
->location
.computed
.closure
= funcs
->copy_closure (val
);
730 set_value_component_location (struct value
*component
, struct value
*whole
)
732 if (VALUE_LVAL (whole
) == lval_internalvar
)
733 VALUE_LVAL (component
) = lval_internalvar_component
;
735 VALUE_LVAL (component
) = VALUE_LVAL (whole
);
737 component
->location
= whole
->location
;
738 if (VALUE_LVAL (whole
) == lval_computed
)
740 struct lval_funcs
*funcs
= whole
->location
.computed
.funcs
;
742 if (funcs
->copy_closure
)
743 component
->location
.computed
.closure
= funcs
->copy_closure (whole
);
748 /* Access to the value history. */
750 /* Record a new value in the value history.
751 Returns the absolute history index of the entry.
752 Result of -1 indicates the value was not saved; otherwise it is the
753 value history index of this new item. */
756 record_latest_value (struct value
*val
)
760 /* We don't want this value to have anything to do with the inferior anymore.
761 In particular, "set $1 = 50" should not affect the variable from which
762 the value was taken, and fast watchpoints should be able to assume that
763 a value on the value history never changes. */
764 if (value_lazy (val
))
765 value_fetch_lazy (val
);
766 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
767 from. This is a bit dubious, because then *&$1 does not just return $1
768 but the current contents of that location. c'est la vie... */
772 /* Here we treat value_history_count as origin-zero
773 and applying to the value being stored now. */
775 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
778 struct value_history_chunk
*new
779 = (struct value_history_chunk
*)
780 xmalloc (sizeof (struct value_history_chunk
));
781 memset (new->values
, 0, sizeof new->values
);
782 new->next
= value_history_chain
;
783 value_history_chain
= new;
786 value_history_chain
->values
[i
] = val
;
788 /* Now we regard value_history_count as origin-one
789 and applying to the value just stored. */
791 return ++value_history_count
;
794 /* Return a copy of the value in the history with sequence number NUM. */
797 access_value_history (int num
)
799 struct value_history_chunk
*chunk
;
804 absnum
+= value_history_count
;
809 error (_("The history is empty."));
811 error (_("There is only one value in the history."));
813 error (_("History does not go back to $$%d."), -num
);
815 if (absnum
> value_history_count
)
816 error (_("History has not yet reached $%d."), absnum
);
820 /* Now absnum is always absolute and origin zero. */
822 chunk
= value_history_chain
;
823 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
827 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
831 show_values (char *num_exp
, int from_tty
)
839 /* "show values +" should print from the stored position.
840 "show values <exp>" should print around value number <exp>. */
841 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
842 num
= parse_and_eval_long (num_exp
) - 5;
846 /* "show values" means print the last 10 values. */
847 num
= value_history_count
- 9;
853 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
855 struct value_print_options opts
;
856 val
= access_value_history (i
);
857 printf_filtered (("$%d = "), i
);
858 get_user_print_options (&opts
);
859 value_print (val
, gdb_stdout
, &opts
);
860 printf_filtered (("\n"));
863 /* The next "show values +" should start after what we just printed. */
866 /* Hitting just return after this command should do the same thing as
867 "show values +". If num_exp is null, this is unnecessary, since
868 "show values +" is not useful after "show values". */
869 if (from_tty
&& num_exp
)
876 /* Internal variables. These are variables within the debugger
877 that hold values assigned by debugger commands.
878 The user refers to them with a '$' prefix
879 that does not appear in the variable names stored internally. */
881 static struct internalvar
*internalvars
;
883 /* If the variable does not already exist create it and give it the value given.
884 If no value is given then the default is zero. */
886 init_if_undefined_command (char* args
, int from_tty
)
888 struct internalvar
* intvar
;
890 /* Parse the expression - this is taken from set_command(). */
891 struct expression
*expr
= parse_expression (args
);
892 register struct cleanup
*old_chain
=
893 make_cleanup (free_current_contents
, &expr
);
895 /* Validate the expression.
896 Was the expression an assignment?
897 Or even an expression at all? */
898 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
899 error (_("Init-if-undefined requires an assignment expression."));
901 /* Extract the variable from the parsed expression.
902 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
903 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
904 error (_("The first parameter to init-if-undefined should be a GDB variable."));
905 intvar
= expr
->elts
[2].internalvar
;
907 /* Only evaluate the expression if the lvalue is void.
908 This may still fail if the expresssion is invalid. */
909 if (TYPE_CODE (value_type (intvar
->value
)) == TYPE_CODE_VOID
)
910 evaluate_expression (expr
);
912 do_cleanups (old_chain
);
916 /* Look up an internal variable with name NAME. NAME should not
917 normally include a dollar sign.
919 If the specified internal variable does not exist,
920 the return value is NULL. */
923 lookup_only_internalvar (const char *name
)
925 struct internalvar
*var
;
927 for (var
= internalvars
; var
; var
= var
->next
)
928 if (strcmp (var
->name
, name
) == 0)
935 /* Create an internal variable with name NAME and with a void value.
936 NAME should not normally include a dollar sign. */
939 create_internalvar (const char *name
)
941 struct internalvar
*var
;
942 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
943 var
->name
= concat (name
, (char *)NULL
);
944 var
->value
= allocate_value (builtin_type_void
);
945 var
->endian
= gdbarch_byte_order (current_gdbarch
);
946 var
->make_value
= NULL
;
948 release_value (var
->value
);
949 var
->next
= internalvars
;
954 /* Create an internal variable with name NAME and register FUN as the
955 function that value_of_internalvar uses to create a value whenever
956 this variable is referenced. NAME should not normally include a
960 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
962 struct internalvar
*var
;
963 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
964 var
->name
= concat (name
, (char *)NULL
);
966 var
->make_value
= fun
;
967 var
->endian
= gdbarch_byte_order (current_gdbarch
);
968 var
->next
= internalvars
;
973 /* Look up an internal variable with name NAME. NAME should not
974 normally include a dollar sign.
976 If the specified internal variable does not exist,
977 one is created, with a void value. */
980 lookup_internalvar (const char *name
)
982 struct internalvar
*var
;
984 var
= lookup_only_internalvar (name
);
988 return create_internalvar (name
);
992 value_of_internalvar (struct internalvar
*var
)
998 if (var
->make_value
!= NULL
)
999 val
= (*var
->make_value
) (var
);
1002 val
= value_copy (var
->value
);
1003 if (value_lazy (val
))
1004 value_fetch_lazy (val
);
1006 /* If the variable's value is a computed lvalue, we want
1007 references to it to produce another computed lvalue, where
1008 referencces and assignments actually operate through the
1009 computed value's functions.
1011 This means that internal variables with computed values
1012 behave a little differently from other internal variables:
1013 assignments to them don't just replace the previous value
1014 altogether. At the moment, this seems like the behavior we
1016 if (var
->value
->lval
== lval_computed
)
1017 VALUE_LVAL (val
) = lval_computed
;
1020 VALUE_LVAL (val
) = lval_internalvar
;
1021 VALUE_INTERNALVAR (val
) = var
;
1025 /* Values are always stored in the target's byte order. When connected to a
1026 target this will most likely always be correct, so there's normally no
1027 need to worry about it.
1029 However, internal variables can be set up before the target endian is
1030 known and so may become out of date. Fix it up before anybody sees.
1032 Internal variables usually hold simple scalar values, and we can
1033 correct those. More complex values (e.g. structures and floating
1034 point types) are left alone, because they would be too complicated
1037 if (var
->endian
!= gdbarch_byte_order (current_gdbarch
))
1039 gdb_byte
*array
= value_contents_raw (val
);
1040 struct type
*type
= check_typedef (value_enclosing_type (val
));
1041 switch (TYPE_CODE (type
))
1045 /* Reverse the bytes. */
1046 for (i
= 0, j
= TYPE_LENGTH (type
) - 1; i
< j
; i
++, j
--)
1049 array
[j
] = array
[i
];
1060 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1061 int bitsize
, struct value
*newval
)
1063 gdb_byte
*addr
= value_contents_writeable (var
->value
) + offset
;
1066 modify_field (addr
, value_as_long (newval
),
1069 memcpy (addr
, value_contents (newval
), TYPE_LENGTH (value_type (newval
)));
1073 set_internalvar (struct internalvar
*var
, struct value
*val
)
1075 struct value
*newval
;
1078 error (_("Cannot overwrite convenience function %s"), var
->name
);
1080 newval
= value_copy (val
);
1081 newval
->modifiable
= 1;
1083 /* Force the value to be fetched from the target now, to avoid problems
1084 later when this internalvar is referenced and the target is gone or
1086 if (value_lazy (newval
))
1087 value_fetch_lazy (newval
);
1089 /* Begin code which must not call error(). If var->value points to
1090 something free'd, an error() obviously leaves a dangling pointer.
1091 But we also get a dangling pointer if var->value points to
1092 something in the value chain (i.e., before release_value is
1093 called), because after the error free_all_values will get called before
1095 value_free (var
->value
);
1096 var
->value
= newval
;
1097 var
->endian
= gdbarch_byte_order (current_gdbarch
);
1098 release_value (newval
);
1099 /* End code which must not call error(). */
1103 internalvar_name (struct internalvar
*var
)
1108 static struct value
*
1109 value_create_internal_function (const char *name
,
1110 internal_function_fn handler
,
1113 struct value
*result
= allocate_value (internal_fn_type
);
1114 gdb_byte
*addr
= value_contents_writeable (result
);
1115 struct internal_function
**fnp
= (struct internal_function
**) addr
;
1116 struct internal_function
*ifn
= XNEW (struct internal_function
);
1117 ifn
->name
= xstrdup (name
);
1118 ifn
->handler
= handler
;
1119 ifn
->cookie
= cookie
;
1125 value_internal_function_name (struct value
*val
)
1127 gdb_byte
*addr
= value_contents_writeable (val
);
1128 struct internal_function
*ifn
= * (struct internal_function
**) addr
;
1133 call_internal_function (struct value
*func
, int argc
, struct value
**argv
)
1135 gdb_byte
*addr
= value_contents_writeable (func
);
1136 struct internal_function
*ifn
= * (struct internal_function
**) addr
;
1137 return (*ifn
->handler
) (ifn
->cookie
, argc
, argv
);
1140 /* The 'function' command. This does nothing -- it is just a
1141 placeholder to let "help function NAME" work. This is also used as
1142 the implementation of the sub-command that is created when
1143 registering an internal function. */
1145 function_command (char *command
, int from_tty
)
1150 /* Clean up if an internal function's command is destroyed. */
1152 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1158 /* Add a new internal function. NAME is the name of the function; DOC
1159 is a documentation string describing the function. HANDLER is
1160 called when the function is invoked. COOKIE is an arbitrary
1161 pointer which is passed to HANDLER and is intended for "user
1164 add_internal_function (const char *name
, const char *doc
,
1165 internal_function_fn handler
, void *cookie
)
1167 struct cmd_list_element
*cmd
;
1168 struct internalvar
*var
= lookup_internalvar (name
);
1169 struct value
*fnval
= value_create_internal_function (name
, handler
, cookie
);
1170 set_internalvar (var
, fnval
);
1173 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1175 cmd
->destroyer
= function_destroyer
;
1178 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1179 prevent cycles / duplicates. */
1182 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1183 htab_t copied_types
)
1185 if (TYPE_OBJFILE (value
->type
) == objfile
)
1186 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1188 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1189 value
->enclosing_type
= copy_type_recursive (objfile
,
1190 value
->enclosing_type
,
1194 /* Update the internal variables and value history when OBJFILE is
1195 discarded; we must copy the types out of the objfile. New global types
1196 will be created for every convenience variable which currently points to
1197 this objfile's types, and the convenience variables will be adjusted to
1198 use the new global types. */
1201 preserve_values (struct objfile
*objfile
)
1203 htab_t copied_types
;
1204 struct value_history_chunk
*cur
;
1205 struct internalvar
*var
;
1209 /* Create the hash table. We allocate on the objfile's obstack, since
1210 it is soon to be deleted. */
1211 copied_types
= create_copied_types_hash (objfile
);
1213 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1214 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1216 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1218 for (var
= internalvars
; var
; var
= var
->next
)
1220 preserve_one_value (var
->value
, objfile
, copied_types
);
1222 for (val
= values_in_python
; val
; val
= val
->next
)
1223 preserve_one_value (val
, objfile
, copied_types
);
1225 htab_delete (copied_types
);
1229 show_convenience (char *ignore
, int from_tty
)
1231 struct internalvar
*var
;
1233 struct value_print_options opts
;
1235 get_user_print_options (&opts
);
1236 for (var
= internalvars
; var
; var
= var
->next
)
1242 printf_filtered (("$%s = "), var
->name
);
1243 value_print (value_of_internalvar (var
), gdb_stdout
,
1245 printf_filtered (("\n"));
1248 printf_unfiltered (_("\
1249 No debugger convenience variables now defined.\n\
1250 Convenience variables have names starting with \"$\";\n\
1251 use \"set\" as in \"set $foo = 5\" to define them.\n"));
1254 /* Extract a value as a C number (either long or double).
1255 Knows how to convert fixed values to double, or
1256 floating values to long.
1257 Does not deallocate the value. */
1260 value_as_long (struct value
*val
)
1262 /* This coerces arrays and functions, which is necessary (e.g.
1263 in disassemble_command). It also dereferences references, which
1264 I suspect is the most logical thing to do. */
1265 val
= coerce_array (val
);
1266 return unpack_long (value_type (val
), value_contents (val
));
1270 value_as_double (struct value
*val
)
1275 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1277 error (_("Invalid floating value found in program."));
1281 /* Extract a value as a C pointer. Does not deallocate the value.
1282 Note that val's type may not actually be a pointer; value_as_long
1283 handles all the cases. */
1285 value_as_address (struct value
*val
)
1287 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1288 whether we want this to be true eventually. */
1290 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1291 non-address (e.g. argument to "signal", "info break", etc.), or
1292 for pointers to char, in which the low bits *are* significant. */
1293 return gdbarch_addr_bits_remove (current_gdbarch
, value_as_long (val
));
1296 /* There are several targets (IA-64, PowerPC, and others) which
1297 don't represent pointers to functions as simply the address of
1298 the function's entry point. For example, on the IA-64, a
1299 function pointer points to a two-word descriptor, generated by
1300 the linker, which contains the function's entry point, and the
1301 value the IA-64 "global pointer" register should have --- to
1302 support position-independent code. The linker generates
1303 descriptors only for those functions whose addresses are taken.
1305 On such targets, it's difficult for GDB to convert an arbitrary
1306 function address into a function pointer; it has to either find
1307 an existing descriptor for that function, or call malloc and
1308 build its own. On some targets, it is impossible for GDB to
1309 build a descriptor at all: the descriptor must contain a jump
1310 instruction; data memory cannot be executed; and code memory
1313 Upon entry to this function, if VAL is a value of type `function'
1314 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1315 value_address (val) is the address of the function. This is what
1316 you'll get if you evaluate an expression like `main'. The call
1317 to COERCE_ARRAY below actually does all the usual unary
1318 conversions, which includes converting values of type `function'
1319 to `pointer to function'. This is the challenging conversion
1320 discussed above. Then, `unpack_long' will convert that pointer
1321 back into an address.
1323 So, suppose the user types `disassemble foo' on an architecture
1324 with a strange function pointer representation, on which GDB
1325 cannot build its own descriptors, and suppose further that `foo'
1326 has no linker-built descriptor. The address->pointer conversion
1327 will signal an error and prevent the command from running, even
1328 though the next step would have been to convert the pointer
1329 directly back into the same address.
1331 The following shortcut avoids this whole mess. If VAL is a
1332 function, just return its address directly. */
1333 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
1334 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
1335 return value_address (val
);
1337 val
= coerce_array (val
);
1339 /* Some architectures (e.g. Harvard), map instruction and data
1340 addresses onto a single large unified address space. For
1341 instance: An architecture may consider a large integer in the
1342 range 0x10000000 .. 0x1000ffff to already represent a data
1343 addresses (hence not need a pointer to address conversion) while
1344 a small integer would still need to be converted integer to
1345 pointer to address. Just assume such architectures handle all
1346 integer conversions in a single function. */
1350 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1351 must admonish GDB hackers to make sure its behavior matches the
1352 compiler's, whenever possible.
1354 In general, I think GDB should evaluate expressions the same way
1355 the compiler does. When the user copies an expression out of
1356 their source code and hands it to a `print' command, they should
1357 get the same value the compiler would have computed. Any
1358 deviation from this rule can cause major confusion and annoyance,
1359 and needs to be justified carefully. In other words, GDB doesn't
1360 really have the freedom to do these conversions in clever and
1363 AndrewC pointed out that users aren't complaining about how GDB
1364 casts integers to pointers; they are complaining that they can't
1365 take an address from a disassembly listing and give it to `x/i'.
1366 This is certainly important.
1368 Adding an architecture method like integer_to_address() certainly
1369 makes it possible for GDB to "get it right" in all circumstances
1370 --- the target has complete control over how things get done, so
1371 people can Do The Right Thing for their target without breaking
1372 anyone else. The standard doesn't specify how integers get
1373 converted to pointers; usually, the ABI doesn't either, but
1374 ABI-specific code is a more reasonable place to handle it. */
1376 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
1377 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
1378 && gdbarch_integer_to_address_p (current_gdbarch
))
1379 return gdbarch_integer_to_address (current_gdbarch
, value_type (val
),
1380 value_contents (val
));
1382 return unpack_long (value_type (val
), value_contents (val
));
1386 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1387 as a long, or as a double, assuming the raw data is described
1388 by type TYPE. Knows how to convert different sizes of values
1389 and can convert between fixed and floating point. We don't assume
1390 any alignment for the raw data. Return value is in host byte order.
1392 If you want functions and arrays to be coerced to pointers, and
1393 references to be dereferenced, call value_as_long() instead.
1395 C++: It is assumed that the front-end has taken care of
1396 all matters concerning pointers to members. A pointer
1397 to member which reaches here is considered to be equivalent
1398 to an INT (or some size). After all, it is only an offset. */
1401 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
1403 enum type_code code
= TYPE_CODE (type
);
1404 int len
= TYPE_LENGTH (type
);
1405 int nosign
= TYPE_UNSIGNED (type
);
1409 case TYPE_CODE_TYPEDEF
:
1410 return unpack_long (check_typedef (type
), valaddr
);
1411 case TYPE_CODE_ENUM
:
1412 case TYPE_CODE_FLAGS
:
1413 case TYPE_CODE_BOOL
:
1415 case TYPE_CODE_CHAR
:
1416 case TYPE_CODE_RANGE
:
1417 case TYPE_CODE_MEMBERPTR
:
1419 return extract_unsigned_integer (valaddr
, len
);
1421 return extract_signed_integer (valaddr
, len
);
1424 return extract_typed_floating (valaddr
, type
);
1426 case TYPE_CODE_DECFLOAT
:
1427 /* libdecnumber has a function to convert from decimal to integer, but
1428 it doesn't work when the decimal number has a fractional part. */
1429 return decimal_to_doublest (valaddr
, len
);
1433 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1434 whether we want this to be true eventually. */
1435 return extract_typed_address (valaddr
, type
);
1438 error (_("Value can't be converted to integer."));
1440 return 0; /* Placate lint. */
1443 /* Return a double value from the specified type and address.
1444 INVP points to an int which is set to 0 for valid value,
1445 1 for invalid value (bad float format). In either case,
1446 the returned double is OK to use. Argument is in target
1447 format, result is in host format. */
1450 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
1452 enum type_code code
;
1456 *invp
= 0; /* Assume valid. */
1457 CHECK_TYPEDEF (type
);
1458 code
= TYPE_CODE (type
);
1459 len
= TYPE_LENGTH (type
);
1460 nosign
= TYPE_UNSIGNED (type
);
1461 if (code
== TYPE_CODE_FLT
)
1463 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1464 floating-point value was valid (using the macro
1465 INVALID_FLOAT). That test/macro have been removed.
1467 It turns out that only the VAX defined this macro and then
1468 only in a non-portable way. Fixing the portability problem
1469 wouldn't help since the VAX floating-point code is also badly
1470 bit-rotten. The target needs to add definitions for the
1471 methods gdbarch_float_format and gdbarch_double_format - these
1472 exactly describe the target floating-point format. The
1473 problem here is that the corresponding floatformat_vax_f and
1474 floatformat_vax_d values these methods should be set to are
1475 also not defined either. Oops!
1477 Hopefully someone will add both the missing floatformat
1478 definitions and the new cases for floatformat_is_valid (). */
1480 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
1486 return extract_typed_floating (valaddr
, type
);
1488 else if (code
== TYPE_CODE_DECFLOAT
)
1489 return decimal_to_doublest (valaddr
, len
);
1492 /* Unsigned -- be sure we compensate for signed LONGEST. */
1493 return (ULONGEST
) unpack_long (type
, valaddr
);
1497 /* Signed -- we are OK with unpack_long. */
1498 return unpack_long (type
, valaddr
);
1502 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1503 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1504 We don't assume any alignment for the raw data. Return value is in
1507 If you want functions and arrays to be coerced to pointers, and
1508 references to be dereferenced, call value_as_address() instead.
1510 C++: It is assumed that the front-end has taken care of
1511 all matters concerning pointers to members. A pointer
1512 to member which reaches here is considered to be equivalent
1513 to an INT (or some size). After all, it is only an offset. */
1516 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
1518 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1519 whether we want this to be true eventually. */
1520 return unpack_long (type
, valaddr
);
1524 /* Get the value of the FIELDN'th field (which must be static) of
1525 TYPE. Return NULL if the field doesn't exist or has been
1529 value_static_field (struct type
*type
, int fieldno
)
1531 struct value
*retval
;
1533 if (TYPE_FIELD_LOC_KIND (type
, fieldno
) == FIELD_LOC_KIND_PHYSADDR
)
1535 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1536 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1540 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1541 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1544 /* With some compilers, e.g. HP aCC, static data members are reported
1545 as non-debuggable symbols */
1546 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
, NULL
, NULL
);
1551 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1552 SYMBOL_VALUE_ADDRESS (msym
));
1557 /* SYM should never have a SYMBOL_CLASS which will require
1558 read_var_value to use the FRAME parameter. */
1559 if (symbol_read_needs_frame (sym
))
1560 warning (_("static field's value depends on the current "
1561 "frame - bad debug info?"));
1562 retval
= read_var_value (sym
, NULL
);
1564 if (retval
&& VALUE_LVAL (retval
) == lval_memory
)
1565 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
),
1566 value_address (retval
));
1571 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1572 You have to be careful here, since the size of the data area for the value
1573 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1574 than the old enclosing type, you have to allocate more space for the data.
1575 The return value is a pointer to the new version of this value structure. */
1578 value_change_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
1580 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
1582 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
1584 val
->enclosing_type
= new_encl_type
;
1588 /* Given a value ARG1 (offset by OFFSET bytes)
1589 of a struct or union type ARG_TYPE,
1590 extract and return the value of one of its (non-static) fields.
1591 FIELDNO says which field. */
1594 value_primitive_field (struct value
*arg1
, int offset
,
1595 int fieldno
, struct type
*arg_type
)
1600 CHECK_TYPEDEF (arg_type
);
1601 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
1603 /* Handle packed fields */
1605 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
1607 v
= value_from_longest (type
,
1608 unpack_field_as_long (arg_type
,
1609 value_contents (arg1
)
1612 v
->bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
) % 8;
1613 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
1614 v
->offset
= value_offset (arg1
) + offset
1615 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1617 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
1619 /* This field is actually a base subobject, so preserve the
1620 entire object's contents for later references to virtual
1623 /* Lazy register values with offsets are not supported. */
1624 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1625 value_fetch_lazy (arg1
);
1627 if (value_lazy (arg1
))
1628 v
= allocate_value_lazy (value_enclosing_type (arg1
));
1631 v
= allocate_value (value_enclosing_type (arg1
));
1632 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
1633 TYPE_LENGTH (value_enclosing_type (arg1
)));
1636 v
->offset
= value_offset (arg1
);
1637 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
1638 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
1642 /* Plain old data member */
1643 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1645 /* Lazy register values with offsets are not supported. */
1646 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1647 value_fetch_lazy (arg1
);
1649 if (value_lazy (arg1
))
1650 v
= allocate_value_lazy (type
);
1653 v
= allocate_value (type
);
1654 memcpy (value_contents_raw (v
),
1655 value_contents_raw (arg1
) + offset
,
1656 TYPE_LENGTH (type
));
1658 v
->offset
= (value_offset (arg1
) + offset
1659 + value_embedded_offset (arg1
));
1661 set_value_component_location (v
, arg1
);
1662 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
1663 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
1667 /* Given a value ARG1 of a struct or union type,
1668 extract and return the value of one of its (non-static) fields.
1669 FIELDNO says which field. */
1672 value_field (struct value
*arg1
, int fieldno
)
1674 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
1677 /* Return a non-virtual function as a value.
1678 F is the list of member functions which contains the desired method.
1679 J is an index into F which provides the desired method.
1681 We only use the symbol for its address, so be happy with either a
1682 full symbol or a minimal symbol.
1686 value_fn_field (struct value
**arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
1690 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
1691 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
1693 struct minimal_symbol
*msym
;
1695 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
1702 gdb_assert (sym
== NULL
);
1703 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
1708 v
= allocate_value (ftype
);
1711 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
1715 /* The minimal symbol might point to a function descriptor;
1716 resolve it to the actual code address instead. */
1717 struct objfile
*objfile
= msymbol_objfile (msym
);
1718 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
1720 set_value_address (v
,
1721 gdbarch_convert_from_func_ptr_addr
1722 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
1727 if (type
!= value_type (*arg1p
))
1728 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
1729 value_addr (*arg1p
)));
1731 /* Move the `this' pointer according to the offset.
1732 VALUE_OFFSET (*arg1p) += offset;
1740 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
1743 Extracting bits depends on endianness of the machine. Compute the
1744 number of least significant bits to discard. For big endian machines,
1745 we compute the total number of bits in the anonymous object, subtract
1746 off the bit count from the MSB of the object to the MSB of the
1747 bitfield, then the size of the bitfield, which leaves the LSB discard
1748 count. For little endian machines, the discard count is simply the
1749 number of bits from the LSB of the anonymous object to the LSB of the
1752 If the field is signed, we also do sign extension. */
1755 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
1759 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
1760 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
1762 struct type
*field_type
;
1764 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8, sizeof (val
));
1765 field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
1766 CHECK_TYPEDEF (field_type
);
1768 /* Extract bits. See comment above. */
1770 if (gdbarch_bits_big_endian (current_gdbarch
))
1771 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
1773 lsbcount
= (bitpos
% 8);
1776 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
1777 If the field is signed, and is negative, then sign extend. */
1779 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
1781 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
1783 if (!TYPE_UNSIGNED (field_type
))
1785 if (val
& (valmask
^ (valmask
>> 1)))
1794 /* Modify the value of a bitfield. ADDR points to a block of memory in
1795 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
1796 is the desired value of the field, in host byte order. BITPOS and BITSIZE
1797 indicate which bits (in target bit order) comprise the bitfield.
1798 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS+BITSIZE <= lbits, and
1799 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
1802 modify_field (gdb_byte
*addr
, LONGEST fieldval
, int bitpos
, int bitsize
)
1805 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
1807 /* If a negative fieldval fits in the field in question, chop
1808 off the sign extension bits. */
1809 if ((~fieldval
& ~(mask
>> 1)) == 0)
1812 /* Warn if value is too big to fit in the field in question. */
1813 if (0 != (fieldval
& ~mask
))
1815 /* FIXME: would like to include fieldval in the message, but
1816 we don't have a sprintf_longest. */
1817 warning (_("Value does not fit in %d bits."), bitsize
);
1819 /* Truncate it, otherwise adjoining fields may be corrupted. */
1823 oword
= extract_unsigned_integer (addr
, sizeof oword
);
1825 /* Shifting for bit field depends on endianness of the target machine. */
1826 if (gdbarch_bits_big_endian (current_gdbarch
))
1827 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
1829 oword
&= ~(mask
<< bitpos
);
1830 oword
|= fieldval
<< bitpos
;
1832 store_unsigned_integer (addr
, sizeof oword
, oword
);
1835 /* Pack NUM into BUF using a target format of TYPE. */
1838 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
1842 type
= check_typedef (type
);
1843 len
= TYPE_LENGTH (type
);
1845 switch (TYPE_CODE (type
))
1848 case TYPE_CODE_CHAR
:
1849 case TYPE_CODE_ENUM
:
1850 case TYPE_CODE_FLAGS
:
1851 case TYPE_CODE_BOOL
:
1852 case TYPE_CODE_RANGE
:
1853 case TYPE_CODE_MEMBERPTR
:
1854 store_signed_integer (buf
, len
, num
);
1859 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
1863 error (_("Unexpected type (%d) encountered for integer constant."),
1869 /* Convert C numbers into newly allocated values. */
1872 value_from_longest (struct type
*type
, LONGEST num
)
1874 struct value
*val
= allocate_value (type
);
1876 pack_long (value_contents_raw (val
), type
, num
);
1882 /* Create a value representing a pointer of type TYPE to the address
1885 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
1887 struct value
*val
= allocate_value (type
);
1888 store_typed_address (value_contents_raw (val
), type
, addr
);
1893 /* Create a value for a string constant to be stored locally
1894 (not in the inferior's memory space, but in GDB memory).
1895 This is analogous to value_from_longest, which also does not
1896 use inferior memory. String shall NOT contain embedded nulls. */
1899 value_from_string (char *ptr
)
1902 int len
= strlen (ptr
);
1903 int lowbound
= current_language
->string_lower_bound
;
1904 struct type
*string_char_type
;
1905 struct type
*rangetype
;
1906 struct type
*stringtype
;
1908 rangetype
= create_range_type ((struct type
*) NULL
,
1910 lowbound
, len
+ lowbound
- 1);
1911 string_char_type
= language_string_char_type (current_language
,
1913 stringtype
= create_array_type ((struct type
*) NULL
,
1916 val
= allocate_value (stringtype
);
1917 memcpy (value_contents_raw (val
), ptr
, len
);
1921 /* Create a value of type TYPE whose contents come from VALADDR, if it
1922 is non-null, and whose memory address (in the inferior) is
1926 value_from_contents_and_address (struct type
*type
,
1927 const gdb_byte
*valaddr
,
1930 struct value
*v
= allocate_value (type
);
1931 if (valaddr
== NULL
)
1932 set_value_lazy (v
, 1);
1934 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
1935 set_value_address (v
, address
);
1936 VALUE_LVAL (v
) = lval_memory
;
1941 value_from_double (struct type
*type
, DOUBLEST num
)
1943 struct value
*val
= allocate_value (type
);
1944 struct type
*base_type
= check_typedef (type
);
1945 enum type_code code
= TYPE_CODE (base_type
);
1946 int len
= TYPE_LENGTH (base_type
);
1948 if (code
== TYPE_CODE_FLT
)
1950 store_typed_floating (value_contents_raw (val
), base_type
, num
);
1953 error (_("Unexpected type encountered for floating constant."));
1959 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
1961 struct value
*val
= allocate_value (type
);
1963 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
1969 coerce_ref (struct value
*arg
)
1971 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
1972 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
1973 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
1974 unpack_pointer (value_type (arg
),
1975 value_contents (arg
)));
1980 coerce_array (struct value
*arg
)
1984 arg
= coerce_ref (arg
);
1985 type
= check_typedef (value_type (arg
));
1987 switch (TYPE_CODE (type
))
1989 case TYPE_CODE_ARRAY
:
1990 if (current_language
->c_style_arrays
)
1991 arg
= value_coerce_array (arg
);
1993 case TYPE_CODE_FUNC
:
1994 arg
= value_coerce_function (arg
);
2001 /* Return true if the function returning the specified type is using
2002 the convention of returning structures in memory (passing in the
2003 address as a hidden first parameter). */
2006 using_struct_return (struct type
*func_type
, struct type
*value_type
)
2008 enum type_code code
= TYPE_CODE (value_type
);
2010 if (code
== TYPE_CODE_ERROR
)
2011 error (_("Function return type unknown."));
2013 if (code
== TYPE_CODE_VOID
)
2014 /* A void return value is never in memory. See also corresponding
2015 code in "print_return_value". */
2018 /* Probe the architecture for the return-value convention. */
2019 return (gdbarch_return_value (current_gdbarch
, func_type
, value_type
,
2021 != RETURN_VALUE_REGISTER_CONVENTION
);
2024 /* Set the initialized field in a value struct. */
2027 set_value_initialized (struct value
*val
, int status
)
2029 val
->initialized
= status
;
2032 /* Return the initialized field in a value struct. */
2035 value_initialized (struct value
*val
)
2037 return val
->initialized
;
2041 _initialize_values (void)
2043 add_cmd ("convenience", no_class
, show_convenience
, _("\
2044 Debugger convenience (\"$foo\") variables.\n\
2045 These variables are created when you assign them values;\n\
2046 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2048 A few convenience variables are given values automatically:\n\
2049 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2050 \"$__\" holds the contents of the last address examined with \"x\"."),
2053 add_cmd ("values", no_class
, show_values
,
2054 _("Elements of value history around item number IDX (or last ten)."),
2057 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2058 Initialize a convenience variable if necessary.\n\
2059 init-if-undefined VARIABLE = EXPRESSION\n\
2060 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2061 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2062 VARIABLE is already initialized."));
2064 add_prefix_cmd ("function", no_class
, function_command
, _("\
2065 Placeholder command for showing help on convenience functions."),
2066 &functionlist
, "function ", 0, &cmdlist
);
2068 internal_fn_type
= alloc_type (NULL
);
2069 TYPE_CODE (internal_fn_type
) = TYPE_CODE_INTERNAL_FUNCTION
;
2070 TYPE_LENGTH (internal_fn_type
) = sizeof (struct internal_function
*);
2071 TYPE_NAME (internal_fn_type
) = "<internal function>";