1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
3 Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
4 1995, 1996, 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005 Free
5 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 2 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, write to the Free Software
21 Foundation, Inc., 59 Temple Place - Suite 330,
22 Boston, MA 02111-1307, USA. */
25 #include "gdb_string.h"
37 #include "gdb_assert.h"
41 /* Prototypes for exported functions. */
43 void _initialize_values (void);
45 /* Prototypes for local functions. */
47 static void show_values (char *, int);
49 static void show_convenience (char *, int);
52 /* The value-history records all the values printed
53 by print commands during this session. Each chunk
54 records 60 consecutive values. The first chunk on
55 the chain records the most recent values.
56 The total number of values is in value_history_count. */
58 #define VALUE_HISTORY_CHUNK 60
60 struct value_history_chunk
62 struct value_history_chunk
*next
;
63 struct value
*values
[VALUE_HISTORY_CHUNK
];
66 /* Chain of chunks now in use. */
68 static struct value_history_chunk
*value_history_chain
;
70 static int value_history_count
; /* Abs number of last entry stored */
72 /* List of all value objects currently allocated
73 (except for those released by calls to release_value)
74 This is so they can be freed after each command. */
76 static struct value
*all_values
;
78 /* Allocate a value that has the correct length for type TYPE. */
81 allocate_value (struct type
*type
)
84 struct type
*atype
= check_typedef (type
);
86 val
= (struct value
*) xzalloc (sizeof (struct value
) + TYPE_LENGTH (atype
));
87 val
->next
= all_values
;
90 val
->enclosing_type
= type
;
91 VALUE_LVAL (val
) = not_lval
;
92 VALUE_ADDRESS (val
) = 0;
93 VALUE_FRAME_ID (val
) = null_frame_id
;
97 VALUE_REGNUM (val
) = -1;
99 val
->optimized_out
= 0;
100 VALUE_EMBEDDED_OFFSET (val
) = 0;
101 VALUE_POINTED_TO_OFFSET (val
) = 0;
106 /* Allocate a value that has the correct length
107 for COUNT repetitions type TYPE. */
110 allocate_repeat_value (struct type
*type
, int count
)
112 int low_bound
= current_language
->string_lower_bound
; /* ??? */
113 /* FIXME-type-allocation: need a way to free this type when we are
115 struct type
*range_type
116 = create_range_type ((struct type
*) NULL
, builtin_type_int
,
117 low_bound
, count
+ low_bound
- 1);
118 /* FIXME-type-allocation: need a way to free this type when we are
120 return allocate_value (create_array_type ((struct type
*) NULL
,
124 /* Accessor methods. */
127 value_type (struct value
*value
)
133 value_offset (struct value
*value
)
135 return value
->offset
;
139 value_bitpos (struct value
*value
)
141 return value
->bitpos
;
145 value_bitsize (struct value
*value
)
147 return value
->bitsize
;
151 value_contents_raw (struct value
*value
)
153 return value
->aligner
.contents
+ value
->embedded_offset
;
157 value_contents_all_raw (struct value
*value
)
159 return value
->aligner
.contents
;
163 value_enclosing_type (struct value
*value
)
165 return value
->enclosing_type
;
169 value_contents_all (struct value
*value
)
172 value_fetch_lazy (value
);
173 return value
->aligner
.contents
;
177 value_lazy (struct value
*value
)
183 set_value_lazy (struct value
*value
, int val
)
189 value_contents (struct value
*value
)
191 return value_contents_writeable (value
);
195 value_contents_writeable (struct value
*value
)
198 value_fetch_lazy (value
);
199 return value
->aligner
.contents
;
203 value_optimized_out (struct value
*value
)
205 return value
->optimized_out
;
209 set_value_optimized_out (struct value
*value
, int val
)
211 value
->optimized_out
= val
;
214 /* Return a mark in the value chain. All values allocated after the
215 mark is obtained (except for those released) are subject to being freed
216 if a subsequent value_free_to_mark is passed the mark. */
223 /* Free all values allocated since MARK was obtained by value_mark
224 (except for those released). */
226 value_free_to_mark (struct value
*mark
)
231 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
239 /* Free all the values that have been allocated (except for those released).
240 Called after each command, successful or not. */
243 free_all_values (void)
248 for (val
= all_values
; val
; val
= next
)
257 /* Remove VAL from the chain all_values
258 so it will not be freed automatically. */
261 release_value (struct value
*val
)
265 if (all_values
== val
)
267 all_values
= val
->next
;
271 for (v
= all_values
; v
; v
= v
->next
)
281 /* Release all values up to mark */
283 value_release_to_mark (struct value
*mark
)
288 for (val
= next
= all_values
; next
; next
= next
->next
)
289 if (next
->next
== mark
)
291 all_values
= next
->next
;
299 /* Return a copy of the value ARG.
300 It contains the same contents, for same memory address,
301 but it's a different block of storage. */
304 value_copy (struct value
*arg
)
306 struct type
*encl_type
= value_enclosing_type (arg
);
307 struct value
*val
= allocate_value (encl_type
);
308 val
->type
= arg
->type
;
309 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
310 VALUE_ADDRESS (val
) = VALUE_ADDRESS (arg
);
311 val
->offset
= arg
->offset
;
312 val
->bitpos
= arg
->bitpos
;
313 val
->bitsize
= arg
->bitsize
;
314 VALUE_FRAME_ID (val
) = VALUE_FRAME_ID (arg
);
315 VALUE_REGNUM (val
) = VALUE_REGNUM (arg
);
316 val
->lazy
= arg
->lazy
;
317 val
->optimized_out
= arg
->optimized_out
;
318 VALUE_EMBEDDED_OFFSET (val
) = VALUE_EMBEDDED_OFFSET (arg
);
319 VALUE_POINTED_TO_OFFSET (val
) = VALUE_POINTED_TO_OFFSET (arg
);
320 val
->modifiable
= arg
->modifiable
;
321 if (!value_lazy (val
))
323 memcpy (value_contents_all_raw (val
), value_contents_all_raw (arg
),
324 TYPE_LENGTH (value_enclosing_type (arg
)));
330 /* Access to the value history. */
332 /* Record a new value in the value history.
333 Returns the absolute history index of the entry.
334 Result of -1 indicates the value was not saved; otherwise it is the
335 value history index of this new item. */
338 record_latest_value (struct value
*val
)
342 /* We don't want this value to have anything to do with the inferior anymore.
343 In particular, "set $1 = 50" should not affect the variable from which
344 the value was taken, and fast watchpoints should be able to assume that
345 a value on the value history never changes. */
346 if (value_lazy (val
))
347 value_fetch_lazy (val
);
348 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
349 from. This is a bit dubious, because then *&$1 does not just return $1
350 but the current contents of that location. c'est la vie... */
354 /* Here we treat value_history_count as origin-zero
355 and applying to the value being stored now. */
357 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
360 struct value_history_chunk
*new
361 = (struct value_history_chunk
*)
362 xmalloc (sizeof (struct value_history_chunk
));
363 memset (new->values
, 0, sizeof new->values
);
364 new->next
= value_history_chain
;
365 value_history_chain
= new;
368 value_history_chain
->values
[i
] = val
;
370 /* Now we regard value_history_count as origin-one
371 and applying to the value just stored. */
373 return ++value_history_count
;
376 /* Return a copy of the value in the history with sequence number NUM. */
379 access_value_history (int num
)
381 struct value_history_chunk
*chunk
;
386 absnum
+= value_history_count
;
391 error ("The history is empty.");
393 error ("There is only one value in the history.");
395 error ("History does not go back to $$%d.", -num
);
397 if (absnum
> value_history_count
)
398 error ("History has not yet reached $%d.", absnum
);
402 /* Now absnum is always absolute and origin zero. */
404 chunk
= value_history_chain
;
405 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
409 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
412 /* Clear the value history entirely.
413 Must be done when new symbol tables are loaded,
414 because the type pointers become invalid. */
417 clear_value_history (void)
419 struct value_history_chunk
*next
;
423 while (value_history_chain
)
425 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
426 if ((val
= value_history_chain
->values
[i
]) != NULL
)
428 next
= value_history_chain
->next
;
429 xfree (value_history_chain
);
430 value_history_chain
= next
;
432 value_history_count
= 0;
436 show_values (char *num_exp
, int from_tty
)
444 /* "info history +" should print from the stored position.
445 "info history <exp>" should print around value number <exp>. */
446 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
447 num
= parse_and_eval_long (num_exp
) - 5;
451 /* "info history" means print the last 10 values. */
452 num
= value_history_count
- 9;
458 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
460 val
= access_value_history (i
);
461 printf_filtered ("$%d = ", i
);
462 value_print (val
, gdb_stdout
, 0, Val_pretty_default
);
463 printf_filtered ("\n");
466 /* The next "info history +" should start after what we just printed. */
469 /* Hitting just return after this command should do the same thing as
470 "info history +". If num_exp is null, this is unnecessary, since
471 "info history +" is not useful after "info history". */
472 if (from_tty
&& num_exp
)
479 /* Internal variables. These are variables within the debugger
480 that hold values assigned by debugger commands.
481 The user refers to them with a '$' prefix
482 that does not appear in the variable names stored internally. */
484 static struct internalvar
*internalvars
;
486 /* Look up an internal variable with name NAME. NAME should not
487 normally include a dollar sign.
489 If the specified internal variable does not exist,
490 one is created, with a void value. */
493 lookup_internalvar (char *name
)
495 struct internalvar
*var
;
497 for (var
= internalvars
; var
; var
= var
->next
)
498 if (strcmp (var
->name
, name
) == 0)
501 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
502 var
->name
= concat (name
, NULL
);
503 var
->value
= allocate_value (builtin_type_void
);
504 release_value (var
->value
);
505 var
->next
= internalvars
;
511 value_of_internalvar (struct internalvar
*var
)
515 val
= value_copy (var
->value
);
516 if (value_lazy (val
))
517 value_fetch_lazy (val
);
518 VALUE_LVAL (val
) = lval_internalvar
;
519 VALUE_INTERNALVAR (val
) = var
;
524 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
525 int bitsize
, struct value
*newval
)
527 bfd_byte
*addr
= value_contents_writeable (var
->value
) + offset
;
530 modify_field (addr
, value_as_long (newval
),
533 memcpy (addr
, value_contents (newval
), TYPE_LENGTH (value_type (newval
)));
537 set_internalvar (struct internalvar
*var
, struct value
*val
)
539 struct value
*newval
;
541 newval
= value_copy (val
);
542 newval
->modifiable
= 1;
544 /* Force the value to be fetched from the target now, to avoid problems
545 later when this internalvar is referenced and the target is gone or
547 if (value_lazy (newval
))
548 value_fetch_lazy (newval
);
550 /* Begin code which must not call error(). If var->value points to
551 something free'd, an error() obviously leaves a dangling pointer.
552 But we also get a danling pointer if var->value points to
553 something in the value chain (i.e., before release_value is
554 called), because after the error free_all_values will get called before
558 release_value (newval
);
559 /* End code which must not call error(). */
563 internalvar_name (struct internalvar
*var
)
568 /* Free all internalvars. Done when new symtabs are loaded,
569 because that makes the values invalid. */
572 clear_internalvars (void)
574 struct internalvar
*var
;
579 internalvars
= var
->next
;
587 show_convenience (char *ignore
, int from_tty
)
589 struct internalvar
*var
;
592 for (var
= internalvars
; var
; var
= var
->next
)
598 printf_filtered ("$%s = ", var
->name
);
599 value_print (var
->value
, gdb_stdout
, 0, Val_pretty_default
);
600 printf_filtered ("\n");
603 printf_unfiltered ("No debugger convenience variables now defined.\n\
604 Convenience variables have names starting with \"$\";\n\
605 use \"set\" as in \"set $foo = 5\" to define them.\n");
608 /* Extract a value as a C number (either long or double).
609 Knows how to convert fixed values to double, or
610 floating values to long.
611 Does not deallocate the value. */
614 value_as_long (struct value
*val
)
616 /* This coerces arrays and functions, which is necessary (e.g.
617 in disassemble_command). It also dereferences references, which
618 I suspect is the most logical thing to do. */
619 val
= coerce_array (val
);
620 return unpack_long (value_type (val
), value_contents (val
));
624 value_as_double (struct value
*val
)
629 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
631 error ("Invalid floating value found in program.");
634 /* Extract a value as a C pointer. Does not deallocate the value.
635 Note that val's type may not actually be a pointer; value_as_long
636 handles all the cases. */
638 value_as_address (struct value
*val
)
640 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
641 whether we want this to be true eventually. */
643 /* ADDR_BITS_REMOVE is wrong if we are being called for a
644 non-address (e.g. argument to "signal", "info break", etc.), or
645 for pointers to char, in which the low bits *are* significant. */
646 return ADDR_BITS_REMOVE (value_as_long (val
));
649 /* There are several targets (IA-64, PowerPC, and others) which
650 don't represent pointers to functions as simply the address of
651 the function's entry point. For example, on the IA-64, a
652 function pointer points to a two-word descriptor, generated by
653 the linker, which contains the function's entry point, and the
654 value the IA-64 "global pointer" register should have --- to
655 support position-independent code. The linker generates
656 descriptors only for those functions whose addresses are taken.
658 On such targets, it's difficult for GDB to convert an arbitrary
659 function address into a function pointer; it has to either find
660 an existing descriptor for that function, or call malloc and
661 build its own. On some targets, it is impossible for GDB to
662 build a descriptor at all: the descriptor must contain a jump
663 instruction; data memory cannot be executed; and code memory
666 Upon entry to this function, if VAL is a value of type `function'
667 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
668 VALUE_ADDRESS (val) is the address of the function. This is what
669 you'll get if you evaluate an expression like `main'. The call
670 to COERCE_ARRAY below actually does all the usual unary
671 conversions, which includes converting values of type `function'
672 to `pointer to function'. This is the challenging conversion
673 discussed above. Then, `unpack_long' will convert that pointer
674 back into an address.
676 So, suppose the user types `disassemble foo' on an architecture
677 with a strange function pointer representation, on which GDB
678 cannot build its own descriptors, and suppose further that `foo'
679 has no linker-built descriptor. The address->pointer conversion
680 will signal an error and prevent the command from running, even
681 though the next step would have been to convert the pointer
682 directly back into the same address.
684 The following shortcut avoids this whole mess. If VAL is a
685 function, just return its address directly. */
686 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
687 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
688 return VALUE_ADDRESS (val
);
690 val
= coerce_array (val
);
692 /* Some architectures (e.g. Harvard), map instruction and data
693 addresses onto a single large unified address space. For
694 instance: An architecture may consider a large integer in the
695 range 0x10000000 .. 0x1000ffff to already represent a data
696 addresses (hence not need a pointer to address conversion) while
697 a small integer would still need to be converted integer to
698 pointer to address. Just assume such architectures handle all
699 integer conversions in a single function. */
703 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
704 must admonish GDB hackers to make sure its behavior matches the
705 compiler's, whenever possible.
707 In general, I think GDB should evaluate expressions the same way
708 the compiler does. When the user copies an expression out of
709 their source code and hands it to a `print' command, they should
710 get the same value the compiler would have computed. Any
711 deviation from this rule can cause major confusion and annoyance,
712 and needs to be justified carefully. In other words, GDB doesn't
713 really have the freedom to do these conversions in clever and
716 AndrewC pointed out that users aren't complaining about how GDB
717 casts integers to pointers; they are complaining that they can't
718 take an address from a disassembly listing and give it to `x/i'.
719 This is certainly important.
721 Adding an architecture method like integer_to_address() certainly
722 makes it possible for GDB to "get it right" in all circumstances
723 --- the target has complete control over how things get done, so
724 people can Do The Right Thing for their target without breaking
725 anyone else. The standard doesn't specify how integers get
726 converted to pointers; usually, the ABI doesn't either, but
727 ABI-specific code is a more reasonable place to handle it. */
729 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
730 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
731 && gdbarch_integer_to_address_p (current_gdbarch
))
732 return gdbarch_integer_to_address (current_gdbarch
, value_type (val
),
733 value_contents (val
));
735 return unpack_long (value_type (val
), value_contents (val
));
739 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
740 as a long, or as a double, assuming the raw data is described
741 by type TYPE. Knows how to convert different sizes of values
742 and can convert between fixed and floating point. We don't assume
743 any alignment for the raw data. Return value is in host byte order.
745 If you want functions and arrays to be coerced to pointers, and
746 references to be dereferenced, call value_as_long() instead.
748 C++: It is assumed that the front-end has taken care of
749 all matters concerning pointers to members. A pointer
750 to member which reaches here is considered to be equivalent
751 to an INT (or some size). After all, it is only an offset. */
754 unpack_long (struct type
*type
, const char *valaddr
)
756 enum type_code code
= TYPE_CODE (type
);
757 int len
= TYPE_LENGTH (type
);
758 int nosign
= TYPE_UNSIGNED (type
);
760 if (current_language
->la_language
== language_scm
761 && is_scmvalue_type (type
))
762 return scm_unpack (type
, valaddr
, TYPE_CODE_INT
);
766 case TYPE_CODE_TYPEDEF
:
767 return unpack_long (check_typedef (type
), valaddr
);
772 case TYPE_CODE_RANGE
:
774 return extract_unsigned_integer (valaddr
, len
);
776 return extract_signed_integer (valaddr
, len
);
779 return extract_typed_floating (valaddr
, type
);
783 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
784 whether we want this to be true eventually. */
785 return extract_typed_address (valaddr
, type
);
787 case TYPE_CODE_MEMBER
:
788 error ("not implemented: member types in unpack_long");
791 error ("Value can't be converted to integer.");
793 return 0; /* Placate lint. */
796 /* Return a double value from the specified type and address.
797 INVP points to an int which is set to 0 for valid value,
798 1 for invalid value (bad float format). In either case,
799 the returned double is OK to use. Argument is in target
800 format, result is in host format. */
803 unpack_double (struct type
*type
, const char *valaddr
, int *invp
)
809 *invp
= 0; /* Assume valid. */
810 CHECK_TYPEDEF (type
);
811 code
= TYPE_CODE (type
);
812 len
= TYPE_LENGTH (type
);
813 nosign
= TYPE_UNSIGNED (type
);
814 if (code
== TYPE_CODE_FLT
)
816 /* NOTE: cagney/2002-02-19: There was a test here to see if the
817 floating-point value was valid (using the macro
818 INVALID_FLOAT). That test/macro have been removed.
820 It turns out that only the VAX defined this macro and then
821 only in a non-portable way. Fixing the portability problem
822 wouldn't help since the VAX floating-point code is also badly
823 bit-rotten. The target needs to add definitions for the
824 methods TARGET_FLOAT_FORMAT and TARGET_DOUBLE_FORMAT - these
825 exactly describe the target floating-point format. The
826 problem here is that the corresponding floatformat_vax_f and
827 floatformat_vax_d values these methods should be set to are
828 also not defined either. Oops!
830 Hopefully someone will add both the missing floatformat
831 definitions and the new cases for floatformat_is_valid (). */
833 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
839 return extract_typed_floating (valaddr
, type
);
843 /* Unsigned -- be sure we compensate for signed LONGEST. */
844 return (ULONGEST
) unpack_long (type
, valaddr
);
848 /* Signed -- we are OK with unpack_long. */
849 return unpack_long (type
, valaddr
);
853 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
854 as a CORE_ADDR, assuming the raw data is described by type TYPE.
855 We don't assume any alignment for the raw data. Return value is in
858 If you want functions and arrays to be coerced to pointers, and
859 references to be dereferenced, call value_as_address() instead.
861 C++: It is assumed that the front-end has taken care of
862 all matters concerning pointers to members. A pointer
863 to member which reaches here is considered to be equivalent
864 to an INT (or some size). After all, it is only an offset. */
867 unpack_pointer (struct type
*type
, const char *valaddr
)
869 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
870 whether we want this to be true eventually. */
871 return unpack_long (type
, valaddr
);
875 /* Get the value of the FIELDN'th field (which must be static) of
876 TYPE. Return NULL if the field doesn't exist or has been
880 value_static_field (struct type
*type
, int fieldno
)
882 struct value
*retval
;
884 if (TYPE_FIELD_STATIC_HAS_ADDR (type
, fieldno
))
886 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
887 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
891 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
892 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0, NULL
);
895 /* With some compilers, e.g. HP aCC, static data members are reported
896 as non-debuggable symbols */
897 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
, NULL
, NULL
);
902 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
903 SYMBOL_VALUE_ADDRESS (msym
));
908 /* SYM should never have a SYMBOL_CLASS which will require
909 read_var_value to use the FRAME parameter. */
910 if (symbol_read_needs_frame (sym
))
911 warning ("static field's value depends on the current "
912 "frame - bad debug info?");
913 retval
= read_var_value (sym
, NULL
);
915 if (retval
&& VALUE_LVAL (retval
) == lval_memory
)
916 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
),
917 VALUE_ADDRESS (retval
));
922 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
923 You have to be careful here, since the size of the data area for the value
924 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
925 than the old enclosing type, you have to allocate more space for the data.
926 The return value is a pointer to the new version of this value structure. */
929 value_change_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
931 if (TYPE_LENGTH (new_encl_type
) <= TYPE_LENGTH (value_enclosing_type (val
)))
933 val
->enclosing_type
= new_encl_type
;
938 struct value
*new_val
;
941 new_val
= (struct value
*) xrealloc (val
, sizeof (struct value
) + TYPE_LENGTH (new_encl_type
));
943 new_val
->enclosing_type
= new_encl_type
;
945 /* We have to make sure this ends up in the same place in the value
946 chain as the original copy, so it's clean-up behavior is the same.
947 If the value has been released, this is a waste of time, but there
948 is no way to tell that in advance, so... */
950 if (val
!= all_values
)
952 for (prev
= all_values
; prev
!= NULL
; prev
= prev
->next
)
954 if (prev
->next
== val
)
956 prev
->next
= new_val
;
966 /* Given a value ARG1 (offset by OFFSET bytes)
967 of a struct or union type ARG_TYPE,
968 extract and return the value of one of its (non-static) fields.
969 FIELDNO says which field. */
972 value_primitive_field (struct value
*arg1
, int offset
,
973 int fieldno
, struct type
*arg_type
)
978 CHECK_TYPEDEF (arg_type
);
979 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
981 /* Handle packed fields */
983 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
985 v
= value_from_longest (type
,
986 unpack_field_as_long (arg_type
,
987 value_contents (arg1
)
990 v
->bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
) % 8;
991 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
992 v
->offset
= value_offset (arg1
) + offset
993 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
995 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
997 /* This field is actually a base subobject, so preserve the
998 entire object's contents for later references to virtual
1000 v
= allocate_value (value_enclosing_type (arg1
));
1002 if (value_lazy (arg1
))
1003 set_value_lazy (v
, 1);
1005 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
1006 TYPE_LENGTH (value_enclosing_type (arg1
)));
1007 v
->offset
= value_offset (arg1
);
1008 VALUE_EMBEDDED_OFFSET (v
)
1010 VALUE_EMBEDDED_OFFSET (arg1
) +
1011 TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1015 /* Plain old data member */
1016 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1017 v
= allocate_value (type
);
1018 if (value_lazy (arg1
))
1019 set_value_lazy (v
, 1);
1021 memcpy (value_contents_raw (v
),
1022 value_contents_raw (arg1
) + offset
,
1023 TYPE_LENGTH (type
));
1024 v
->offset
= (value_offset (arg1
) + offset
1025 + VALUE_EMBEDDED_OFFSET (arg1
));
1027 VALUE_LVAL (v
) = VALUE_LVAL (arg1
);
1028 if (VALUE_LVAL (arg1
) == lval_internalvar
)
1029 VALUE_LVAL (v
) = lval_internalvar_component
;
1030 VALUE_ADDRESS (v
) = VALUE_ADDRESS (arg1
);
1031 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
1032 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
1033 /* VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset
1034 + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; */
1038 /* Given a value ARG1 of a struct or union type,
1039 extract and return the value of one of its (non-static) fields.
1040 FIELDNO says which field. */
1043 value_field (struct value
*arg1
, int fieldno
)
1045 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
1048 /* Return a non-virtual function as a value.
1049 F is the list of member functions which contains the desired method.
1050 J is an index into F which provides the desired method.
1052 We only use the symbol for its address, so be happy with either a
1053 full symbol or a minimal symbol.
1057 value_fn_field (struct value
**arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
1061 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
1062 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
1064 struct minimal_symbol
*msym
;
1066 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0, NULL
);
1073 gdb_assert (sym
== NULL
);
1074 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
1079 v
= allocate_value (ftype
);
1082 VALUE_ADDRESS (v
) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym
));
1086 VALUE_ADDRESS (v
) = SYMBOL_VALUE_ADDRESS (msym
);
1091 if (type
!= value_type (*arg1p
))
1092 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
1093 value_addr (*arg1p
)));
1095 /* Move the `this' pointer according to the offset.
1096 VALUE_OFFSET (*arg1p) += offset;
1104 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
1107 Extracting bits depends on endianness of the machine. Compute the
1108 number of least significant bits to discard. For big endian machines,
1109 we compute the total number of bits in the anonymous object, subtract
1110 off the bit count from the MSB of the object to the MSB of the
1111 bitfield, then the size of the bitfield, which leaves the LSB discard
1112 count. For little endian machines, the discard count is simply the
1113 number of bits from the LSB of the anonymous object to the LSB of the
1116 If the field is signed, we also do sign extension. */
1119 unpack_field_as_long (struct type
*type
, const char *valaddr
, int fieldno
)
1123 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
1124 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
1126 struct type
*field_type
;
1128 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8, sizeof (val
));
1129 field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
1130 CHECK_TYPEDEF (field_type
);
1132 /* Extract bits. See comment above. */
1134 if (BITS_BIG_ENDIAN
)
1135 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
1137 lsbcount
= (bitpos
% 8);
1140 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
1141 If the field is signed, and is negative, then sign extend. */
1143 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
1145 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
1147 if (!TYPE_UNSIGNED (field_type
))
1149 if (val
& (valmask
^ (valmask
>> 1)))
1158 /* Modify the value of a bitfield. ADDR points to a block of memory in
1159 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
1160 is the desired value of the field, in host byte order. BITPOS and BITSIZE
1161 indicate which bits (in target bit order) comprise the bitfield.
1162 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS+BITSIZE <= lbits, and
1163 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
1166 modify_field (char *addr
, LONGEST fieldval
, int bitpos
, int bitsize
)
1169 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
1171 /* If a negative fieldval fits in the field in question, chop
1172 off the sign extension bits. */
1173 if ((~fieldval
& ~(mask
>> 1)) == 0)
1176 /* Warn if value is too big to fit in the field in question. */
1177 if (0 != (fieldval
& ~mask
))
1179 /* FIXME: would like to include fieldval in the message, but
1180 we don't have a sprintf_longest. */
1181 warning ("Value does not fit in %d bits.", bitsize
);
1183 /* Truncate it, otherwise adjoining fields may be corrupted. */
1187 oword
= extract_unsigned_integer (addr
, sizeof oword
);
1189 /* Shifting for bit field depends on endianness of the target machine. */
1190 if (BITS_BIG_ENDIAN
)
1191 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
1193 oword
&= ~(mask
<< bitpos
);
1194 oword
|= fieldval
<< bitpos
;
1196 store_unsigned_integer (addr
, sizeof oword
, oword
);
1199 /* Convert C numbers into newly allocated values */
1202 value_from_longest (struct type
*type
, LONGEST num
)
1204 struct value
*val
= allocate_value (type
);
1205 enum type_code code
;
1208 code
= TYPE_CODE (type
);
1209 len
= TYPE_LENGTH (type
);
1213 case TYPE_CODE_TYPEDEF
:
1214 type
= check_typedef (type
);
1217 case TYPE_CODE_CHAR
:
1218 case TYPE_CODE_ENUM
:
1219 case TYPE_CODE_BOOL
:
1220 case TYPE_CODE_RANGE
:
1221 store_signed_integer (value_contents_raw (val
), len
, num
);
1226 store_typed_address (value_contents_raw (val
), type
, (CORE_ADDR
) num
);
1230 error ("Unexpected type (%d) encountered for integer constant.", code
);
1236 /* Create a value representing a pointer of type TYPE to the address
1239 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
1241 struct value
*val
= allocate_value (type
);
1242 store_typed_address (value_contents_raw (val
), type
, addr
);
1247 /* Create a value for a string constant to be stored locally
1248 (not in the inferior's memory space, but in GDB memory).
1249 This is analogous to value_from_longest, which also does not
1250 use inferior memory. String shall NOT contain embedded nulls. */
1253 value_from_string (char *ptr
)
1256 int len
= strlen (ptr
);
1257 int lowbound
= current_language
->string_lower_bound
;
1258 struct type
*string_char_type
;
1259 struct type
*rangetype
;
1260 struct type
*stringtype
;
1262 rangetype
= create_range_type ((struct type
*) NULL
,
1264 lowbound
, len
+ lowbound
- 1);
1265 string_char_type
= language_string_char_type (current_language
,
1267 stringtype
= create_array_type ((struct type
*) NULL
,
1270 val
= allocate_value (stringtype
);
1271 memcpy (value_contents_raw (val
), ptr
, len
);
1276 value_from_double (struct type
*type
, DOUBLEST num
)
1278 struct value
*val
= allocate_value (type
);
1279 struct type
*base_type
= check_typedef (type
);
1280 enum type_code code
= TYPE_CODE (base_type
);
1281 int len
= TYPE_LENGTH (base_type
);
1283 if (code
== TYPE_CODE_FLT
)
1285 store_typed_floating (value_contents_raw (val
), base_type
, num
);
1288 error ("Unexpected type encountered for floating constant.");
1294 coerce_ref (struct value
*arg
)
1296 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
1297 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
1298 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
1299 unpack_pointer (value_type (arg
),
1300 value_contents (arg
)));
1305 coerce_array (struct value
*arg
)
1307 arg
= coerce_ref (arg
);
1308 if (current_language
->c_style_arrays
1309 && TYPE_CODE (value_type (arg
)) == TYPE_CODE_ARRAY
)
1310 arg
= value_coerce_array (arg
);
1311 if (TYPE_CODE (value_type (arg
)) == TYPE_CODE_FUNC
)
1312 arg
= value_coerce_function (arg
);
1317 coerce_number (struct value
*arg
)
1319 arg
= coerce_array (arg
);
1320 arg
= coerce_enum (arg
);
1325 coerce_enum (struct value
*arg
)
1327 if (TYPE_CODE (check_typedef (value_type (arg
))) == TYPE_CODE_ENUM
)
1328 arg
= value_cast (builtin_type_unsigned_int
, arg
);
1333 /* Should we use DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS instead of
1334 EXTRACT_RETURN_VALUE? GCC_P is true if compiled with gcc and TYPE
1335 is the type (which is known to be struct, union or array).
1337 On most machines, the struct convention is used unless we are
1338 using gcc and the type is of a special size. */
1339 /* As of about 31 Mar 93, GCC was changed to be compatible with the
1340 native compiler. GCC 2.3.3 was the last release that did it the
1341 old way. Since gcc2_compiled was not changed, we have no
1342 way to correctly win in all cases, so we just do the right thing
1343 for gcc1 and for gcc2 after this change. Thus it loses for gcc
1344 2.0-2.3.3. This is somewhat unfortunate, but changing gcc2_compiled
1345 would cause more chaos than dealing with some struct returns being
1347 /* NOTE: cagney/2004-06-13: Deleted check for "gcc_p". GCC 1.x is
1351 generic_use_struct_convention (int gcc_p
, struct type
*value_type
)
1353 return !(TYPE_LENGTH (value_type
) == 1
1354 || TYPE_LENGTH (value_type
) == 2
1355 || TYPE_LENGTH (value_type
) == 4
1356 || TYPE_LENGTH (value_type
) == 8);
1359 /* Return true if the function returning the specified type is using
1360 the convention of returning structures in memory (passing in the
1361 address as a hidden first parameter). GCC_P is nonzero if compiled
1365 using_struct_return (struct type
*value_type
, int gcc_p
)
1367 enum type_code code
= TYPE_CODE (value_type
);
1369 if (code
== TYPE_CODE_ERROR
)
1370 error ("Function return type unknown.");
1372 if (code
== TYPE_CODE_VOID
)
1373 /* A void return value is never in memory. See also corresponding
1374 code in "print_return_value". */
1377 /* Probe the architecture for the return-value convention. */
1378 return (gdbarch_return_value (current_gdbarch
, value_type
,
1380 != RETURN_VALUE_REGISTER_CONVENTION
);
1384 _initialize_values (void)
1386 add_cmd ("convenience", no_class
, show_convenience
,
1387 "Debugger convenience (\"$foo\") variables.\n\
1388 These variables are created when you assign them values;\n\
1389 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\n\
1390 A few convenience variables are given values automatically:\n\
1391 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
1392 \"$__\" holds the contents of the last address examined with \"x\".",
1395 add_cmd ("values", no_class
, show_values
,
1396 "Elements of value history around item number IDX (or last ten).",