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. */
883 struct internalvar
*next
;
887 /* True if this internalvar is the canonical name for a convenience
891 /* If this function is non-NULL, it is used to compute a fresh value
892 on every access to the internalvar. */
893 internalvar_make_value make_value
;
895 /* To reduce dependencies on target properties (like byte order) that
896 may change during the lifetime of an internal variable, we store
897 simple scalar values as host objects. */
898 union internalvar_data
901 struct internal_function
*f
;
907 static struct internalvar
*internalvars
;
909 /* If the variable does not already exist create it and give it the value given.
910 If no value is given then the default is zero. */
912 init_if_undefined_command (char* args
, int from_tty
)
914 struct internalvar
* intvar
;
916 /* Parse the expression - this is taken from set_command(). */
917 struct expression
*expr
= parse_expression (args
);
918 register struct cleanup
*old_chain
=
919 make_cleanup (free_current_contents
, &expr
);
921 /* Validate the expression.
922 Was the expression an assignment?
923 Or even an expression at all? */
924 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
925 error (_("Init-if-undefined requires an assignment expression."));
927 /* Extract the variable from the parsed expression.
928 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
929 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
930 error (_("The first parameter to init-if-undefined should be a GDB variable."));
931 intvar
= expr
->elts
[2].internalvar
;
933 /* Only evaluate the expression if the lvalue is void.
934 This may still fail if the expresssion is invalid. */
935 if (TYPE_CODE (intvar
->type
) == TYPE_CODE_VOID
)
936 evaluate_expression (expr
);
938 do_cleanups (old_chain
);
942 /* Look up an internal variable with name NAME. NAME should not
943 normally include a dollar sign.
945 If the specified internal variable does not exist,
946 the return value is NULL. */
949 lookup_only_internalvar (const char *name
)
951 struct internalvar
*var
;
953 for (var
= internalvars
; var
; var
= var
->next
)
954 if (strcmp (var
->name
, name
) == 0)
961 /* Create an internal variable with name NAME and with a void value.
962 NAME should not normally include a dollar sign. */
965 create_internalvar (const char *name
)
967 struct internalvar
*var
;
968 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
969 var
->name
= concat (name
, (char *)NULL
);
970 var
->type
= builtin_type_void
;
971 var
->make_value
= NULL
;
973 var
->next
= internalvars
;
978 /* Create an internal variable with name NAME and register FUN as the
979 function that value_of_internalvar uses to create a value whenever
980 this variable is referenced. NAME should not normally include a
984 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
986 struct internalvar
*var
= create_internalvar (name
);
987 var
->make_value
= fun
;
991 /* Look up an internal variable with name NAME. NAME should not
992 normally include a dollar sign.
994 If the specified internal variable does not exist,
995 one is created, with a void value. */
998 lookup_internalvar (const char *name
)
1000 struct internalvar
*var
;
1002 var
= lookup_only_internalvar (name
);
1006 return create_internalvar (name
);
1010 value_of_internalvar (struct internalvar
*var
)
1014 if (var
->make_value
!= NULL
)
1015 val
= (*var
->make_value
) (var
);
1018 switch (TYPE_CODE (var
->type
))
1020 case TYPE_CODE_VOID
:
1021 case TYPE_CODE_INTERNAL_FUNCTION
:
1022 val
= allocate_value (var
->type
);
1026 val
= value_from_longest (var
->type
, var
->u
.l
);
1030 val
= value_from_pointer (var
->type
, var
->u
.a
);
1034 val
= value_copy (var
->u
.v
);
1038 if (value_lazy (val
))
1039 value_fetch_lazy (val
);
1041 /* If the variable's value is a computed lvalue, we want
1042 references to it to produce another computed lvalue, where
1043 referencces and assignments actually operate through the
1044 computed value's functions.
1046 This means that internal variables with computed values
1047 behave a little differently from other internal variables:
1048 assignments to them don't just replace the previous value
1049 altogether. At the moment, this seems like the behavior we
1051 if (val
->lval
!= lval_computed
)
1053 VALUE_LVAL (val
) = lval_internalvar
;
1054 VALUE_INTERNALVAR (val
) = var
;
1062 get_internalvar_integer (struct internalvar
*var
, LONGEST
*result
)
1064 switch (TYPE_CODE (var
->type
))
1076 get_internalvar_function (struct internalvar
*var
,
1077 struct internal_function
**result
)
1079 switch (TYPE_CODE (var
->type
))
1081 case TYPE_CODE_INTERNAL_FUNCTION
:
1091 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1092 int bitsize
, struct value
*newval
)
1096 switch (TYPE_CODE (var
->type
))
1098 case TYPE_CODE_VOID
:
1099 case TYPE_CODE_INTERNAL_FUNCTION
:
1102 /* We can never get a component of a basic type. */
1103 internal_error (__FILE__
, __LINE__
, "set_internalvar_component");
1106 addr
= value_contents_writeable (var
->u
.v
);
1109 modify_field (addr
+ offset
,
1110 value_as_long (newval
), bitpos
, bitsize
);
1112 memcpy (addr
+ offset
, value_contents (newval
),
1113 TYPE_LENGTH (value_type (newval
)));
1119 set_internalvar (struct internalvar
*var
, struct value
*val
)
1121 struct type
*new_type
= check_typedef (value_type (val
));
1122 union internalvar_data new_data
= { 0 };
1125 error (_("Cannot overwrite convenience function %s"), var
->name
);
1127 /* Prepare new contents. */
1128 switch (TYPE_CODE (new_type
))
1130 case TYPE_CODE_VOID
:
1133 case TYPE_CODE_INTERNAL_FUNCTION
:
1134 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1135 get_internalvar_function (VALUE_INTERNALVAR (val
), &new_data
.f
);
1139 new_data
.l
= value_as_long (val
);
1143 new_data
.a
= value_as_address (val
);
1147 new_data
.v
= value_copy (val
);
1148 new_data
.v
->modifiable
= 1;
1150 /* Force the value to be fetched from the target now, to avoid problems
1151 later when this internalvar is referenced and the target is gone or
1153 if (value_lazy (new_data
.v
))
1154 value_fetch_lazy (new_data
.v
);
1156 /* Release the value from the value chain to prevent it from being
1157 deleted by free_all_values. From here on this function should not
1158 call error () until new_data is installed into the var->u to avoid
1160 release_value (new_data
.v
);
1164 /* Clean up old contents. */
1165 clear_internalvar (var
);
1168 var
->type
= new_type
;
1170 /* End code which must not call error(). */
1174 set_internalvar_integer (struct internalvar
*var
, LONGEST l
)
1176 /* Clean up old contents. */
1177 clear_internalvar (var
);
1179 /* Use a platform-independent 32-bit integer type. */
1180 var
->type
= builtin_type_int32
;
1185 set_internalvar_function (struct internalvar
*var
, struct internal_function
*f
)
1187 /* Clean up old contents. */
1188 clear_internalvar (var
);
1190 var
->type
= internal_fn_type
;
1195 clear_internalvar (struct internalvar
*var
)
1197 /* Clean up old contents. */
1198 switch (TYPE_CODE (var
->type
))
1200 case TYPE_CODE_VOID
:
1201 case TYPE_CODE_INTERNAL_FUNCTION
:
1207 value_free (var
->u
.v
);
1211 /* Set to void type. */
1212 var
->type
= builtin_type_void
;
1216 internalvar_name (struct internalvar
*var
)
1221 static struct internal_function
*
1222 create_internal_function (const char *name
,
1223 internal_function_fn handler
, void *cookie
)
1225 struct internal_function
*ifn
= XNEW (struct internal_function
);
1226 ifn
->name
= xstrdup (name
);
1227 ifn
->handler
= handler
;
1228 ifn
->cookie
= cookie
;
1233 value_internal_function_name (struct value
*val
)
1235 struct internal_function
*ifn
;
1238 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1239 result
= get_internalvar_function (VALUE_INTERNALVAR (val
), &ifn
);
1240 gdb_assert (result
);
1246 call_internal_function (struct value
*func
, int argc
, struct value
**argv
)
1248 struct internal_function
*ifn
;
1251 gdb_assert (VALUE_LVAL (func
) == lval_internalvar
);
1252 result
= get_internalvar_function (VALUE_INTERNALVAR (func
), &ifn
);
1253 gdb_assert (result
);
1255 return (*ifn
->handler
) (ifn
->cookie
, argc
, argv
);
1258 /* The 'function' command. This does nothing -- it is just a
1259 placeholder to let "help function NAME" work. This is also used as
1260 the implementation of the sub-command that is created when
1261 registering an internal function. */
1263 function_command (char *command
, int from_tty
)
1268 /* Clean up if an internal function's command is destroyed. */
1270 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1276 /* Add a new internal function. NAME is the name of the function; DOC
1277 is a documentation string describing the function. HANDLER is
1278 called when the function is invoked. COOKIE is an arbitrary
1279 pointer which is passed to HANDLER and is intended for "user
1282 add_internal_function (const char *name
, const char *doc
,
1283 internal_function_fn handler
, void *cookie
)
1285 struct cmd_list_element
*cmd
;
1286 struct internal_function
*ifn
;
1287 struct internalvar
*var
= lookup_internalvar (name
);
1289 ifn
= create_internal_function (name
, handler
, cookie
);
1290 set_internalvar_function (var
, ifn
);
1293 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1295 cmd
->destroyer
= function_destroyer
;
1298 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1299 prevent cycles / duplicates. */
1302 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1303 htab_t copied_types
)
1305 if (TYPE_OBJFILE (value
->type
) == objfile
)
1306 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1308 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1309 value
->enclosing_type
= copy_type_recursive (objfile
,
1310 value
->enclosing_type
,
1314 /* Update the internal variables and value history when OBJFILE is
1315 discarded; we must copy the types out of the objfile. New global types
1316 will be created for every convenience variable which currently points to
1317 this objfile's types, and the convenience variables will be adjusted to
1318 use the new global types. */
1321 preserve_values (struct objfile
*objfile
)
1323 htab_t copied_types
;
1324 struct value_history_chunk
*cur
;
1325 struct internalvar
*var
;
1329 /* Create the hash table. We allocate on the objfile's obstack, since
1330 it is soon to be deleted. */
1331 copied_types
= create_copied_types_hash (objfile
);
1333 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1334 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1336 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1338 for (var
= internalvars
; var
; var
= var
->next
)
1340 if (TYPE_OBJFILE (var
->type
) == objfile
)
1341 var
->type
= copy_type_recursive (objfile
, var
->type
, copied_types
);
1343 switch (TYPE_CODE (var
->type
))
1345 case TYPE_CODE_VOID
:
1346 case TYPE_CODE_INTERNAL_FUNCTION
:
1352 preserve_one_value (var
->u
.v
, objfile
, copied_types
);
1357 for (val
= values_in_python
; val
; val
= val
->next
)
1358 preserve_one_value (val
, objfile
, copied_types
);
1360 htab_delete (copied_types
);
1364 show_convenience (char *ignore
, int from_tty
)
1366 struct internalvar
*var
;
1368 struct value_print_options opts
;
1370 get_user_print_options (&opts
);
1371 for (var
= internalvars
; var
; var
= var
->next
)
1377 printf_filtered (("$%s = "), var
->name
);
1378 value_print (value_of_internalvar (var
), gdb_stdout
,
1380 printf_filtered (("\n"));
1383 printf_unfiltered (_("\
1384 No debugger convenience variables now defined.\n\
1385 Convenience variables have names starting with \"$\";\n\
1386 use \"set\" as in \"set $foo = 5\" to define them.\n"));
1389 /* Extract a value as a C number (either long or double).
1390 Knows how to convert fixed values to double, or
1391 floating values to long.
1392 Does not deallocate the value. */
1395 value_as_long (struct value
*val
)
1397 /* This coerces arrays and functions, which is necessary (e.g.
1398 in disassemble_command). It also dereferences references, which
1399 I suspect is the most logical thing to do. */
1400 val
= coerce_array (val
);
1401 return unpack_long (value_type (val
), value_contents (val
));
1405 value_as_double (struct value
*val
)
1410 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1412 error (_("Invalid floating value found in program."));
1416 /* Extract a value as a C pointer. Does not deallocate the value.
1417 Note that val's type may not actually be a pointer; value_as_long
1418 handles all the cases. */
1420 value_as_address (struct value
*val
)
1422 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1423 whether we want this to be true eventually. */
1425 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1426 non-address (e.g. argument to "signal", "info break", etc.), or
1427 for pointers to char, in which the low bits *are* significant. */
1428 return gdbarch_addr_bits_remove (current_gdbarch
, value_as_long (val
));
1431 /* There are several targets (IA-64, PowerPC, and others) which
1432 don't represent pointers to functions as simply the address of
1433 the function's entry point. For example, on the IA-64, a
1434 function pointer points to a two-word descriptor, generated by
1435 the linker, which contains the function's entry point, and the
1436 value the IA-64 "global pointer" register should have --- to
1437 support position-independent code. The linker generates
1438 descriptors only for those functions whose addresses are taken.
1440 On such targets, it's difficult for GDB to convert an arbitrary
1441 function address into a function pointer; it has to either find
1442 an existing descriptor for that function, or call malloc and
1443 build its own. On some targets, it is impossible for GDB to
1444 build a descriptor at all: the descriptor must contain a jump
1445 instruction; data memory cannot be executed; and code memory
1448 Upon entry to this function, if VAL is a value of type `function'
1449 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1450 value_address (val) is the address of the function. This is what
1451 you'll get if you evaluate an expression like `main'. The call
1452 to COERCE_ARRAY below actually does all the usual unary
1453 conversions, which includes converting values of type `function'
1454 to `pointer to function'. This is the challenging conversion
1455 discussed above. Then, `unpack_long' will convert that pointer
1456 back into an address.
1458 So, suppose the user types `disassemble foo' on an architecture
1459 with a strange function pointer representation, on which GDB
1460 cannot build its own descriptors, and suppose further that `foo'
1461 has no linker-built descriptor. The address->pointer conversion
1462 will signal an error and prevent the command from running, even
1463 though the next step would have been to convert the pointer
1464 directly back into the same address.
1466 The following shortcut avoids this whole mess. If VAL is a
1467 function, just return its address directly. */
1468 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
1469 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
1470 return value_address (val
);
1472 val
= coerce_array (val
);
1474 /* Some architectures (e.g. Harvard), map instruction and data
1475 addresses onto a single large unified address space. For
1476 instance: An architecture may consider a large integer in the
1477 range 0x10000000 .. 0x1000ffff to already represent a data
1478 addresses (hence not need a pointer to address conversion) while
1479 a small integer would still need to be converted integer to
1480 pointer to address. Just assume such architectures handle all
1481 integer conversions in a single function. */
1485 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1486 must admonish GDB hackers to make sure its behavior matches the
1487 compiler's, whenever possible.
1489 In general, I think GDB should evaluate expressions the same way
1490 the compiler does. When the user copies an expression out of
1491 their source code and hands it to a `print' command, they should
1492 get the same value the compiler would have computed. Any
1493 deviation from this rule can cause major confusion and annoyance,
1494 and needs to be justified carefully. In other words, GDB doesn't
1495 really have the freedom to do these conversions in clever and
1498 AndrewC pointed out that users aren't complaining about how GDB
1499 casts integers to pointers; they are complaining that they can't
1500 take an address from a disassembly listing and give it to `x/i'.
1501 This is certainly important.
1503 Adding an architecture method like integer_to_address() certainly
1504 makes it possible for GDB to "get it right" in all circumstances
1505 --- the target has complete control over how things get done, so
1506 people can Do The Right Thing for their target without breaking
1507 anyone else. The standard doesn't specify how integers get
1508 converted to pointers; usually, the ABI doesn't either, but
1509 ABI-specific code is a more reasonable place to handle it. */
1511 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
1512 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
1513 && gdbarch_integer_to_address_p (current_gdbarch
))
1514 return gdbarch_integer_to_address (current_gdbarch
, value_type (val
),
1515 value_contents (val
));
1517 return unpack_long (value_type (val
), value_contents (val
));
1521 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1522 as a long, or as a double, assuming the raw data is described
1523 by type TYPE. Knows how to convert different sizes of values
1524 and can convert between fixed and floating point. We don't assume
1525 any alignment for the raw data. Return value is in host byte order.
1527 If you want functions and arrays to be coerced to pointers, and
1528 references to be dereferenced, call value_as_long() instead.
1530 C++: It is assumed that the front-end has taken care of
1531 all matters concerning pointers to members. A pointer
1532 to member which reaches here is considered to be equivalent
1533 to an INT (or some size). After all, it is only an offset. */
1536 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
1538 enum type_code code
= TYPE_CODE (type
);
1539 int len
= TYPE_LENGTH (type
);
1540 int nosign
= TYPE_UNSIGNED (type
);
1544 case TYPE_CODE_TYPEDEF
:
1545 return unpack_long (check_typedef (type
), valaddr
);
1546 case TYPE_CODE_ENUM
:
1547 case TYPE_CODE_FLAGS
:
1548 case TYPE_CODE_BOOL
:
1550 case TYPE_CODE_CHAR
:
1551 case TYPE_CODE_RANGE
:
1552 case TYPE_CODE_MEMBERPTR
:
1554 return extract_unsigned_integer (valaddr
, len
);
1556 return extract_signed_integer (valaddr
, len
);
1559 return extract_typed_floating (valaddr
, type
);
1561 case TYPE_CODE_DECFLOAT
:
1562 /* libdecnumber has a function to convert from decimal to integer, but
1563 it doesn't work when the decimal number has a fractional part. */
1564 return decimal_to_doublest (valaddr
, len
);
1568 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1569 whether we want this to be true eventually. */
1570 return extract_typed_address (valaddr
, type
);
1573 error (_("Value can't be converted to integer."));
1575 return 0; /* Placate lint. */
1578 /* Return a double value from the specified type and address.
1579 INVP points to an int which is set to 0 for valid value,
1580 1 for invalid value (bad float format). In either case,
1581 the returned double is OK to use. Argument is in target
1582 format, result is in host format. */
1585 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
1587 enum type_code code
;
1591 *invp
= 0; /* Assume valid. */
1592 CHECK_TYPEDEF (type
);
1593 code
= TYPE_CODE (type
);
1594 len
= TYPE_LENGTH (type
);
1595 nosign
= TYPE_UNSIGNED (type
);
1596 if (code
== TYPE_CODE_FLT
)
1598 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1599 floating-point value was valid (using the macro
1600 INVALID_FLOAT). That test/macro have been removed.
1602 It turns out that only the VAX defined this macro and then
1603 only in a non-portable way. Fixing the portability problem
1604 wouldn't help since the VAX floating-point code is also badly
1605 bit-rotten. The target needs to add definitions for the
1606 methods gdbarch_float_format and gdbarch_double_format - these
1607 exactly describe the target floating-point format. The
1608 problem here is that the corresponding floatformat_vax_f and
1609 floatformat_vax_d values these methods should be set to are
1610 also not defined either. Oops!
1612 Hopefully someone will add both the missing floatformat
1613 definitions and the new cases for floatformat_is_valid (). */
1615 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
1621 return extract_typed_floating (valaddr
, type
);
1623 else if (code
== TYPE_CODE_DECFLOAT
)
1624 return decimal_to_doublest (valaddr
, len
);
1627 /* Unsigned -- be sure we compensate for signed LONGEST. */
1628 return (ULONGEST
) unpack_long (type
, valaddr
);
1632 /* Signed -- we are OK with unpack_long. */
1633 return unpack_long (type
, valaddr
);
1637 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1638 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1639 We don't assume any alignment for the raw data. Return value is in
1642 If you want functions and arrays to be coerced to pointers, and
1643 references to be dereferenced, call value_as_address() instead.
1645 C++: It is assumed that the front-end has taken care of
1646 all matters concerning pointers to members. A pointer
1647 to member which reaches here is considered to be equivalent
1648 to an INT (or some size). After all, it is only an offset. */
1651 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
1653 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1654 whether we want this to be true eventually. */
1655 return unpack_long (type
, valaddr
);
1659 /* Get the value of the FIELDN'th field (which must be static) of
1660 TYPE. Return NULL if the field doesn't exist or has been
1664 value_static_field (struct type
*type
, int fieldno
)
1666 struct value
*retval
;
1668 if (TYPE_FIELD_LOC_KIND (type
, fieldno
) == FIELD_LOC_KIND_PHYSADDR
)
1670 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1671 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1675 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1676 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1679 /* With some compilers, e.g. HP aCC, static data members are reported
1680 as non-debuggable symbols */
1681 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
, NULL
, NULL
);
1686 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1687 SYMBOL_VALUE_ADDRESS (msym
));
1692 /* SYM should never have a SYMBOL_CLASS which will require
1693 read_var_value to use the FRAME parameter. */
1694 if (symbol_read_needs_frame (sym
))
1695 warning (_("static field's value depends on the current "
1696 "frame - bad debug info?"));
1697 retval
= read_var_value (sym
, NULL
);
1699 if (retval
&& VALUE_LVAL (retval
) == lval_memory
)
1700 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
),
1701 value_address (retval
));
1706 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1707 You have to be careful here, since the size of the data area for the value
1708 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1709 than the old enclosing type, you have to allocate more space for the data.
1710 The return value is a pointer to the new version of this value structure. */
1713 value_change_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
1715 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
1717 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
1719 val
->enclosing_type
= new_encl_type
;
1723 /* Given a value ARG1 (offset by OFFSET bytes)
1724 of a struct or union type ARG_TYPE,
1725 extract and return the value of one of its (non-static) fields.
1726 FIELDNO says which field. */
1729 value_primitive_field (struct value
*arg1
, int offset
,
1730 int fieldno
, struct type
*arg_type
)
1735 CHECK_TYPEDEF (arg_type
);
1736 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
1738 /* Handle packed fields */
1740 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
1742 v
= value_from_longest (type
,
1743 unpack_field_as_long (arg_type
,
1744 value_contents (arg1
)
1747 v
->bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
) % 8;
1748 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
1749 v
->offset
= value_offset (arg1
) + offset
1750 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1752 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
1754 /* This field is actually a base subobject, so preserve the
1755 entire object's contents for later references to virtual
1758 /* Lazy register values with offsets are not supported. */
1759 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1760 value_fetch_lazy (arg1
);
1762 if (value_lazy (arg1
))
1763 v
= allocate_value_lazy (value_enclosing_type (arg1
));
1766 v
= allocate_value (value_enclosing_type (arg1
));
1767 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
1768 TYPE_LENGTH (value_enclosing_type (arg1
)));
1771 v
->offset
= value_offset (arg1
);
1772 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
1773 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
1777 /* Plain old data member */
1778 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1780 /* Lazy register values with offsets are not supported. */
1781 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1782 value_fetch_lazy (arg1
);
1784 if (value_lazy (arg1
))
1785 v
= allocate_value_lazy (type
);
1788 v
= allocate_value (type
);
1789 memcpy (value_contents_raw (v
),
1790 value_contents_raw (arg1
) + offset
,
1791 TYPE_LENGTH (type
));
1793 v
->offset
= (value_offset (arg1
) + offset
1794 + value_embedded_offset (arg1
));
1796 set_value_component_location (v
, arg1
);
1797 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
1798 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
1802 /* Given a value ARG1 of a struct or union type,
1803 extract and return the value of one of its (non-static) fields.
1804 FIELDNO says which field. */
1807 value_field (struct value
*arg1
, int fieldno
)
1809 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
1812 /* Return a non-virtual function as a value.
1813 F is the list of member functions which contains the desired method.
1814 J is an index into F which provides the desired method.
1816 We only use the symbol for its address, so be happy with either a
1817 full symbol or a minimal symbol.
1821 value_fn_field (struct value
**arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
1825 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
1826 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
1828 struct minimal_symbol
*msym
;
1830 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
1837 gdb_assert (sym
== NULL
);
1838 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
1843 v
= allocate_value (ftype
);
1846 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
1850 /* The minimal symbol might point to a function descriptor;
1851 resolve it to the actual code address instead. */
1852 struct objfile
*objfile
= msymbol_objfile (msym
);
1853 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
1855 set_value_address (v
,
1856 gdbarch_convert_from_func_ptr_addr
1857 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
1862 if (type
!= value_type (*arg1p
))
1863 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
1864 value_addr (*arg1p
)));
1866 /* Move the `this' pointer according to the offset.
1867 VALUE_OFFSET (*arg1p) += offset;
1875 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
1878 Extracting bits depends on endianness of the machine. Compute the
1879 number of least significant bits to discard. For big endian machines,
1880 we compute the total number of bits in the anonymous object, subtract
1881 off the bit count from the MSB of the object to the MSB of the
1882 bitfield, then the size of the bitfield, which leaves the LSB discard
1883 count. For little endian machines, the discard count is simply the
1884 number of bits from the LSB of the anonymous object to the LSB of the
1887 If the field is signed, we also do sign extension. */
1890 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
1894 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
1895 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
1897 struct type
*field_type
;
1899 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8, sizeof (val
));
1900 field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
1901 CHECK_TYPEDEF (field_type
);
1903 /* Extract bits. See comment above. */
1905 if (gdbarch_bits_big_endian (current_gdbarch
))
1906 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
1908 lsbcount
= (bitpos
% 8);
1911 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
1912 If the field is signed, and is negative, then sign extend. */
1914 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
1916 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
1918 if (!TYPE_UNSIGNED (field_type
))
1920 if (val
& (valmask
^ (valmask
>> 1)))
1929 /* Modify the value of a bitfield. ADDR points to a block of memory in
1930 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
1931 is the desired value of the field, in host byte order. BITPOS and BITSIZE
1932 indicate which bits (in target bit order) comprise the bitfield.
1933 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS+BITSIZE <= lbits, and
1934 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
1937 modify_field (gdb_byte
*addr
, LONGEST fieldval
, int bitpos
, int bitsize
)
1940 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
1942 /* If a negative fieldval fits in the field in question, chop
1943 off the sign extension bits. */
1944 if ((~fieldval
& ~(mask
>> 1)) == 0)
1947 /* Warn if value is too big to fit in the field in question. */
1948 if (0 != (fieldval
& ~mask
))
1950 /* FIXME: would like to include fieldval in the message, but
1951 we don't have a sprintf_longest. */
1952 warning (_("Value does not fit in %d bits."), bitsize
);
1954 /* Truncate it, otherwise adjoining fields may be corrupted. */
1958 oword
= extract_unsigned_integer (addr
, sizeof oword
);
1960 /* Shifting for bit field depends on endianness of the target machine. */
1961 if (gdbarch_bits_big_endian (current_gdbarch
))
1962 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
1964 oword
&= ~(mask
<< bitpos
);
1965 oword
|= fieldval
<< bitpos
;
1967 store_unsigned_integer (addr
, sizeof oword
, oword
);
1970 /* Pack NUM into BUF using a target format of TYPE. */
1973 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
1977 type
= check_typedef (type
);
1978 len
= TYPE_LENGTH (type
);
1980 switch (TYPE_CODE (type
))
1983 case TYPE_CODE_CHAR
:
1984 case TYPE_CODE_ENUM
:
1985 case TYPE_CODE_FLAGS
:
1986 case TYPE_CODE_BOOL
:
1987 case TYPE_CODE_RANGE
:
1988 case TYPE_CODE_MEMBERPTR
:
1989 store_signed_integer (buf
, len
, num
);
1994 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
1998 error (_("Unexpected type (%d) encountered for integer constant."),
2004 /* Convert C numbers into newly allocated values. */
2007 value_from_longest (struct type
*type
, LONGEST num
)
2009 struct value
*val
= allocate_value (type
);
2011 pack_long (value_contents_raw (val
), type
, num
);
2017 /* Create a value representing a pointer of type TYPE to the address
2020 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
2022 struct value
*val
= allocate_value (type
);
2023 store_typed_address (value_contents_raw (val
), type
, addr
);
2028 /* Create a value for a string constant to be stored locally
2029 (not in the inferior's memory space, but in GDB memory).
2030 This is analogous to value_from_longest, which also does not
2031 use inferior memory. String shall NOT contain embedded nulls. */
2034 value_from_string (char *ptr
)
2037 int len
= strlen (ptr
);
2038 int lowbound
= current_language
->string_lower_bound
;
2039 struct type
*string_char_type
;
2040 struct type
*rangetype
;
2041 struct type
*stringtype
;
2043 rangetype
= create_range_type ((struct type
*) NULL
,
2045 lowbound
, len
+ lowbound
- 1);
2046 string_char_type
= language_string_char_type (current_language
,
2048 stringtype
= create_array_type ((struct type
*) NULL
,
2051 val
= allocate_value (stringtype
);
2052 memcpy (value_contents_raw (val
), ptr
, len
);
2056 /* Create a value of type TYPE whose contents come from VALADDR, if it
2057 is non-null, and whose memory address (in the inferior) is
2061 value_from_contents_and_address (struct type
*type
,
2062 const gdb_byte
*valaddr
,
2065 struct value
*v
= allocate_value (type
);
2066 if (valaddr
== NULL
)
2067 set_value_lazy (v
, 1);
2069 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
2070 set_value_address (v
, address
);
2071 VALUE_LVAL (v
) = lval_memory
;
2076 value_from_double (struct type
*type
, DOUBLEST num
)
2078 struct value
*val
= allocate_value (type
);
2079 struct type
*base_type
= check_typedef (type
);
2080 enum type_code code
= TYPE_CODE (base_type
);
2081 int len
= TYPE_LENGTH (base_type
);
2083 if (code
== TYPE_CODE_FLT
)
2085 store_typed_floating (value_contents_raw (val
), base_type
, num
);
2088 error (_("Unexpected type encountered for floating constant."));
2094 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
2096 struct value
*val
= allocate_value (type
);
2098 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
2104 coerce_ref (struct value
*arg
)
2106 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
2107 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
2108 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
2109 unpack_pointer (value_type (arg
),
2110 value_contents (arg
)));
2115 coerce_array (struct value
*arg
)
2119 arg
= coerce_ref (arg
);
2120 type
= check_typedef (value_type (arg
));
2122 switch (TYPE_CODE (type
))
2124 case TYPE_CODE_ARRAY
:
2125 if (current_language
->c_style_arrays
)
2126 arg
= value_coerce_array (arg
);
2128 case TYPE_CODE_FUNC
:
2129 arg
= value_coerce_function (arg
);
2136 /* Return true if the function returning the specified type is using
2137 the convention of returning structures in memory (passing in the
2138 address as a hidden first parameter). */
2141 using_struct_return (struct type
*func_type
, struct type
*value_type
)
2143 enum type_code code
= TYPE_CODE (value_type
);
2145 if (code
== TYPE_CODE_ERROR
)
2146 error (_("Function return type unknown."));
2148 if (code
== TYPE_CODE_VOID
)
2149 /* A void return value is never in memory. See also corresponding
2150 code in "print_return_value". */
2153 /* Probe the architecture for the return-value convention. */
2154 return (gdbarch_return_value (current_gdbarch
, func_type
, value_type
,
2156 != RETURN_VALUE_REGISTER_CONVENTION
);
2159 /* Set the initialized field in a value struct. */
2162 set_value_initialized (struct value
*val
, int status
)
2164 val
->initialized
= status
;
2167 /* Return the initialized field in a value struct. */
2170 value_initialized (struct value
*val
)
2172 return val
->initialized
;
2176 _initialize_values (void)
2178 add_cmd ("convenience", no_class
, show_convenience
, _("\
2179 Debugger convenience (\"$foo\") variables.\n\
2180 These variables are created when you assign them values;\n\
2181 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2183 A few convenience variables are given values automatically:\n\
2184 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2185 \"$__\" holds the contents of the last address examined with \"x\"."),
2188 add_cmd ("values", no_class
, show_values
,
2189 _("Elements of value history around item number IDX (or last ten)."),
2192 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2193 Initialize a convenience variable if necessary.\n\
2194 init-if-undefined VARIABLE = EXPRESSION\n\
2195 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2196 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2197 VARIABLE is already initialized."));
2199 add_prefix_cmd ("function", no_class
, function_command
, _("\
2200 Placeholder command for showing help on convenience functions."),
2201 &functionlist
, "function ", 0, &cmdlist
);
2203 internal_fn_type
= alloc_type (NULL
);
2204 TYPE_CODE (internal_fn_type
) = TYPE_CODE_INTERNAL_FUNCTION
;
2205 TYPE_NAME (internal_fn_type
) = "<internal function>";