1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
2 Copyright 1986, 87, 89, 91, 93, 94, 95, 96, 97, 1998
3 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
23 #include "gdb_string.h"
36 /* Prototypes for exported functions. */
38 void _initialize_values PARAMS ((void));
40 /* Prototypes for local functions. */
42 static value_ptr value_headof PARAMS ((value_ptr, struct type *,
45 static void show_values PARAMS ((char *, int));
47 static void show_convenience PARAMS ((char *, int));
49 static int vb_match PARAMS ((struct type *, int, struct type *));
51 /* The value-history records all the values printed
52 by print commands during this session. Each chunk
53 records 60 consecutive values. The first chunk on
54 the chain records the most recent values.
55 The total number of values is in value_history_count. */
57 #define VALUE_HISTORY_CHUNK 60
59 struct value_history_chunk
61 struct value_history_chunk *next;
62 value_ptr values[VALUE_HISTORY_CHUNK];
65 /* Chain of chunks now in use. */
67 static struct value_history_chunk *value_history_chain;
69 static int value_history_count; /* Abs number of last entry stored */
71 /* List of all value objects currently allocated
72 (except for those released by calls to release_value)
73 This is so they can be freed after each command. */
75 static value_ptr all_values;
77 /* Allocate a value that has the correct length for type TYPE. */
83 register value_ptr val;
84 struct type *atype = check_typedef (type);
86 val = (struct value *) xmalloc (sizeof (struct value) + TYPE_LENGTH (atype));
87 VALUE_NEXT (val) = all_values;
89 VALUE_TYPE (val) = type;
90 VALUE_ENCLOSING_TYPE (val) = type;
91 VALUE_LVAL (val) = not_lval;
92 VALUE_ADDRESS (val) = 0;
93 VALUE_FRAME (val) = 0;
94 VALUE_OFFSET (val) = 0;
95 VALUE_BITPOS (val) = 0;
96 VALUE_BITSIZE (val) = 0;
97 VALUE_REGNO (val) = -1;
99 VALUE_OPTIMIZED_OUT (val) = 0;
100 VALUE_BFD_SECTION (val) = NULL;
101 VALUE_EMBEDDED_OFFSET (val) = 0;
102 VALUE_POINTED_TO_OFFSET (val) = 0;
107 /* Allocate a value that has the correct length
108 for COUNT repetitions type TYPE. */
111 allocate_repeat_value (type, count)
115 int low_bound = current_language->string_lower_bound; /* ??? */
116 /* FIXME-type-allocation: need a way to free this type when we are
118 struct type *range_type
119 = create_range_type ((struct type *) NULL, builtin_type_int,
120 low_bound, count + low_bound - 1);
121 /* FIXME-type-allocation: need a way to free this type when we are
123 return allocate_value (create_array_type ((struct type *) NULL,
127 /* Return a mark in the value chain. All values allocated after the
128 mark is obtained (except for those released) are subject to being freed
129 if a subsequent value_free_to_mark is passed the mark. */
136 /* Free all values allocated since MARK was obtained by value_mark
137 (except for those released). */
139 value_free_to_mark (mark)
144 for (val = all_values; val && val != mark; val = next)
146 next = VALUE_NEXT (val);
152 /* Free all the values that have been allocated (except for those released).
153 Called after each command, successful or not. */
158 register value_ptr val, next;
160 for (val = all_values; val; val = next)
162 next = VALUE_NEXT (val);
169 /* Remove VAL from the chain all_values
170 so it will not be freed automatically. */
174 register value_ptr val;
176 register value_ptr v;
178 if (all_values == val)
180 all_values = val->next;
184 for (v = all_values; v; v = v->next)
194 /* Release all values up to mark */
196 value_release_to_mark (mark)
201 for (val = next = all_values; next; next = VALUE_NEXT (next))
202 if (VALUE_NEXT (next) == mark)
204 all_values = VALUE_NEXT (next);
205 VALUE_NEXT (next) = 0;
212 /* Return a copy of the value ARG.
213 It contains the same contents, for same memory address,
214 but it's a different block of storage. */
220 register struct type *encl_type = VALUE_ENCLOSING_TYPE (arg);
221 register value_ptr val = allocate_value (encl_type);
222 VALUE_TYPE (val) = VALUE_TYPE (arg);
223 VALUE_LVAL (val) = VALUE_LVAL (arg);
224 VALUE_ADDRESS (val) = VALUE_ADDRESS (arg);
225 VALUE_OFFSET (val) = VALUE_OFFSET (arg);
226 VALUE_BITPOS (val) = VALUE_BITPOS (arg);
227 VALUE_BITSIZE (val) = VALUE_BITSIZE (arg);
228 VALUE_FRAME (val) = VALUE_FRAME (arg);
229 VALUE_REGNO (val) = VALUE_REGNO (arg);
230 VALUE_LAZY (val) = VALUE_LAZY (arg);
231 VALUE_OPTIMIZED_OUT (val) = VALUE_OPTIMIZED_OUT (arg);
232 VALUE_EMBEDDED_OFFSET (val) = VALUE_EMBEDDED_OFFSET (arg);
233 VALUE_POINTED_TO_OFFSET (val) = VALUE_POINTED_TO_OFFSET (arg);
234 VALUE_BFD_SECTION (val) = VALUE_BFD_SECTION (arg);
235 val->modifiable = arg->modifiable;
236 if (!VALUE_LAZY (val))
238 memcpy (VALUE_CONTENTS_ALL_RAW (val), VALUE_CONTENTS_ALL_RAW (arg),
239 TYPE_LENGTH (VALUE_ENCLOSING_TYPE (arg)));
245 /* Access to the value history. */
247 /* Record a new value in the value history.
248 Returns the absolute history index of the entry.
249 Result of -1 indicates the value was not saved; otherwise it is the
250 value history index of this new item. */
253 record_latest_value (val)
258 /* We don't want this value to have anything to do with the inferior anymore.
259 In particular, "set $1 = 50" should not affect the variable from which
260 the value was taken, and fast watchpoints should be able to assume that
261 a value on the value history never changes. */
262 if (VALUE_LAZY (val))
263 value_fetch_lazy (val);
264 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
265 from. This is a bit dubious, because then *&$1 does not just return $1
266 but the current contents of that location. c'est la vie... */
270 /* Here we treat value_history_count as origin-zero
271 and applying to the value being stored now. */
273 i = value_history_count % VALUE_HISTORY_CHUNK;
276 register struct value_history_chunk *new
277 = (struct value_history_chunk *)
278 xmalloc (sizeof (struct value_history_chunk));
279 memset (new->values, 0, sizeof new->values);
280 new->next = value_history_chain;
281 value_history_chain = new;
284 value_history_chain->values[i] = val;
286 /* Now we regard value_history_count as origin-one
287 and applying to the value just stored. */
289 return ++value_history_count;
292 /* Return a copy of the value in the history with sequence number NUM. */
295 access_value_history (num)
298 register struct value_history_chunk *chunk;
300 register int absnum = num;
303 absnum += value_history_count;
308 error ("The history is empty.");
310 error ("There is only one value in the history.");
312 error ("History does not go back to $$%d.", -num);
314 if (absnum > value_history_count)
315 error ("History has not yet reached $%d.", absnum);
319 /* Now absnum is always absolute and origin zero. */
321 chunk = value_history_chain;
322 for (i = (value_history_count - 1) / VALUE_HISTORY_CHUNK - absnum / VALUE_HISTORY_CHUNK;
326 return value_copy (chunk->values[absnum % VALUE_HISTORY_CHUNK]);
329 /* Clear the value history entirely.
330 Must be done when new symbol tables are loaded,
331 because the type pointers become invalid. */
334 clear_value_history ()
336 register struct value_history_chunk *next;
338 register value_ptr val;
340 while (value_history_chain)
342 for (i = 0; i < VALUE_HISTORY_CHUNK; i++)
343 if ((val = value_history_chain->values[i]) != NULL)
345 next = value_history_chain->next;
346 free ((PTR) value_history_chain);
347 value_history_chain = next;
349 value_history_count = 0;
353 show_values (num_exp, from_tty)
358 register value_ptr val;
363 /* "info history +" should print from the stored position.
364 "info history <exp>" should print around value number <exp>. */
365 if (num_exp[0] != '+' || num_exp[1] != '\0')
366 num = parse_and_eval_address (num_exp) - 5;
370 /* "info history" means print the last 10 values. */
371 num = value_history_count - 9;
377 for (i = num; i < num + 10 && i <= value_history_count; i++)
379 val = access_value_history (i);
380 printf_filtered ("$%d = ", i);
381 value_print (val, gdb_stdout, 0, Val_pretty_default);
382 printf_filtered ("\n");
385 /* The next "info history +" should start after what we just printed. */
388 /* Hitting just return after this command should do the same thing as
389 "info history +". If num_exp is null, this is unnecessary, since
390 "info history +" is not useful after "info history". */
391 if (from_tty && num_exp)
398 /* Internal variables. These are variables within the debugger
399 that hold values assigned by debugger commands.
400 The user refers to them with a '$' prefix
401 that does not appear in the variable names stored internally. */
403 static struct internalvar *internalvars;
405 /* Look up an internal variable with name NAME. NAME should not
406 normally include a dollar sign.
408 If the specified internal variable does not exist,
409 one is created, with a void value. */
412 lookup_internalvar (name)
415 register struct internalvar *var;
417 for (var = internalvars; var; var = var->next)
418 if (STREQ (var->name, name))
421 var = (struct internalvar *) xmalloc (sizeof (struct internalvar));
422 var->name = concat (name, NULL);
423 var->value = allocate_value (builtin_type_void);
424 release_value (var->value);
425 var->next = internalvars;
431 value_of_internalvar (var)
432 struct internalvar *var;
434 register value_ptr val;
436 #ifdef IS_TRAPPED_INTERNALVAR
437 if (IS_TRAPPED_INTERNALVAR (var->name))
438 return VALUE_OF_TRAPPED_INTERNALVAR (var);
441 val = value_copy (var->value);
442 if (VALUE_LAZY (val))
443 value_fetch_lazy (val);
444 VALUE_LVAL (val) = lval_internalvar;
445 VALUE_INTERNALVAR (val) = var;
450 set_internalvar_component (var, offset, bitpos, bitsize, newval)
451 struct internalvar *var;
452 int offset, bitpos, bitsize;
455 register char *addr = VALUE_CONTENTS (var->value) + offset;
457 #ifdef IS_TRAPPED_INTERNALVAR
458 if (IS_TRAPPED_INTERNALVAR (var->name))
459 SET_TRAPPED_INTERNALVAR (var, newval, bitpos, bitsize, offset);
463 modify_field (addr, value_as_long (newval),
466 memcpy (addr, VALUE_CONTENTS (newval), TYPE_LENGTH (VALUE_TYPE (newval)));
470 set_internalvar (var, val)
471 struct internalvar *var;
476 #ifdef IS_TRAPPED_INTERNALVAR
477 if (IS_TRAPPED_INTERNALVAR (var->name))
478 SET_TRAPPED_INTERNALVAR (var, val, 0, 0, 0);
481 newval = value_copy (val);
482 newval->modifiable = 1;
484 /* Force the value to be fetched from the target now, to avoid problems
485 later when this internalvar is referenced and the target is gone or
487 if (VALUE_LAZY (newval))
488 value_fetch_lazy (newval);
490 /* Begin code which must not call error(). If var->value points to
491 something free'd, an error() obviously leaves a dangling pointer.
492 But we also get a danling pointer if var->value points to
493 something in the value chain (i.e., before release_value is
494 called), because after the error free_all_values will get called before
496 free ((PTR) var->value);
498 release_value (newval);
499 /* End code which must not call error(). */
503 internalvar_name (var)
504 struct internalvar *var;
509 /* Free all internalvars. Done when new symtabs are loaded,
510 because that makes the values invalid. */
513 clear_internalvars ()
515 register struct internalvar *var;
520 internalvars = var->next;
521 free ((PTR) var->name);
522 free ((PTR) var->value);
528 show_convenience (ignore, from_tty)
532 register struct internalvar *var;
535 for (var = internalvars; var; var = var->next)
537 #ifdef IS_TRAPPED_INTERNALVAR
538 if (IS_TRAPPED_INTERNALVAR (var->name))
545 printf_filtered ("$%s = ", var->name);
546 value_print (var->value, gdb_stdout, 0, Val_pretty_default);
547 printf_filtered ("\n");
550 printf_unfiltered ("No debugger convenience variables now defined.\n\
551 Convenience variables have names starting with \"$\";\n\
552 use \"set\" as in \"set $foo = 5\" to define them.\n");
555 /* Extract a value as a C number (either long or double).
556 Knows how to convert fixed values to double, or
557 floating values to long.
558 Does not deallocate the value. */
562 register value_ptr val;
564 /* This coerces arrays and functions, which is necessary (e.g.
565 in disassemble_command). It also dereferences references, which
566 I suspect is the most logical thing to do. */
568 return unpack_long (VALUE_TYPE (val), VALUE_CONTENTS (val));
572 value_as_double (val)
573 register value_ptr val;
578 foo = unpack_double (VALUE_TYPE (val), VALUE_CONTENTS (val), &inv);
580 error ("Invalid floating value found in program.");
583 /* Extract a value as a C pointer.
584 Does not deallocate the value. */
586 value_as_pointer (val)
589 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
590 whether we want this to be true eventually. */
592 /* ADDR_BITS_REMOVE is wrong if we are being called for a
593 non-address (e.g. argument to "signal", "info break", etc.), or
594 for pointers to char, in which the low bits *are* significant. */
595 return ADDR_BITS_REMOVE (value_as_long (val));
597 return value_as_long (val);
601 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
602 as a long, or as a double, assuming the raw data is described
603 by type TYPE. Knows how to convert different sizes of values
604 and can convert between fixed and floating point. We don't assume
605 any alignment for the raw data. Return value is in host byte order.
607 If you want functions and arrays to be coerced to pointers, and
608 references to be dereferenced, call value_as_long() instead.
610 C++: It is assumed that the front-end has taken care of
611 all matters concerning pointers to members. A pointer
612 to member which reaches here is considered to be equivalent
613 to an INT (or some size). After all, it is only an offset. */
616 unpack_long (type, valaddr)
620 register enum type_code code = TYPE_CODE (type);
621 register int len = TYPE_LENGTH (type);
622 register int nosign = TYPE_UNSIGNED (type);
624 if (current_language->la_language == language_scm
625 && is_scmvalue_type (type))
626 return scm_unpack (type, valaddr, TYPE_CODE_INT);
630 case TYPE_CODE_TYPEDEF:
631 return unpack_long (check_typedef (type), valaddr);
636 case TYPE_CODE_RANGE:
638 return extract_unsigned_integer (valaddr, len);
640 return extract_signed_integer (valaddr, len);
643 return extract_floating (valaddr, len);
647 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
648 whether we want this to be true eventually. */
649 if (GDB_TARGET_IS_D10V
651 return D10V_MAKE_DADDR (extract_address (valaddr, len));
652 return extract_address (valaddr, len);
654 case TYPE_CODE_MEMBER:
655 error ("not implemented: member types in unpack_long");
658 error ("Value can't be converted to integer.");
660 return 0; /* Placate lint. */
663 /* Return a double value from the specified type and address.
664 INVP points to an int which is set to 0 for valid value,
665 1 for invalid value (bad float format). In either case,
666 the returned double is OK to use. Argument is in target
667 format, result is in host format. */
670 unpack_double (type, valaddr, invp)
679 *invp = 0; /* Assume valid. */
680 CHECK_TYPEDEF (type);
681 code = TYPE_CODE (type);
682 len = TYPE_LENGTH (type);
683 nosign = TYPE_UNSIGNED (type);
684 if (code == TYPE_CODE_FLT)
687 if (INVALID_FLOAT (valaddr, len))
690 return 1.234567891011121314;
693 return extract_floating (valaddr, len);
697 /* Unsigned -- be sure we compensate for signed LONGEST. */
698 #if !defined (_MSC_VER) || (_MSC_VER > 900)
699 return (ULONGEST) unpack_long (type, valaddr);
701 /* FIXME!!! msvc22 doesn't support unsigned __int64 -> double */
702 return (LONGEST) unpack_long (type, valaddr);
703 #endif /* _MSC_VER */
707 /* Signed -- we are OK with unpack_long. */
708 return unpack_long (type, valaddr);
712 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
713 as a CORE_ADDR, assuming the raw data is described by type TYPE.
714 We don't assume any alignment for the raw data. Return value is in
717 If you want functions and arrays to be coerced to pointers, and
718 references to be dereferenced, call value_as_pointer() instead.
720 C++: It is assumed that the front-end has taken care of
721 all matters concerning pointers to members. A pointer
722 to member which reaches here is considered to be equivalent
723 to an INT (or some size). After all, it is only an offset. */
726 unpack_pointer (type, valaddr)
730 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
731 whether we want this to be true eventually. */
732 return unpack_long (type, valaddr);
735 /* Get the value of the FIELDN'th field (which must be static) of TYPE. */
738 value_static_field (type, fieldno)
744 if (TYPE_FIELD_STATIC_HAS_ADDR (type, fieldno))
746 addr = TYPE_FIELD_STATIC_PHYSADDR (type, fieldno);
751 char *phys_name = TYPE_FIELD_STATIC_PHYSNAME (type, fieldno);
752 struct symbol *sym = lookup_symbol (phys_name, 0, VAR_NAMESPACE, 0, NULL);
755 /* With some compilers, e.g. HP aCC, static data members are reported
756 as non-debuggable symbols */
757 struct minimal_symbol *msym = lookup_minimal_symbol (phys_name, NULL, NULL);
762 addr = SYMBOL_VALUE_ADDRESS (msym);
763 sect = SYMBOL_BFD_SECTION (msym);
768 addr = SYMBOL_VALUE_ADDRESS (sym);
769 sect = SYMBOL_BFD_SECTION (sym);
771 SET_FIELD_PHYSADDR (TYPE_FIELD (type, fieldno), addr);
773 return value_at (TYPE_FIELD_TYPE (type, fieldno), addr, sect);
776 /* Given a value ARG1 (offset by OFFSET bytes)
777 of a struct or union type ARG_TYPE,
778 extract and return the value of one of its (non-static) fields.
779 FIELDNO says which field. */
782 value_primitive_field (arg1, offset, fieldno, arg_type)
783 register value_ptr arg1;
785 register int fieldno;
786 register struct type *arg_type;
788 register value_ptr v;
789 register struct type *type;
791 CHECK_TYPEDEF (arg_type);
792 type = TYPE_FIELD_TYPE (arg_type, fieldno);
794 /* Handle packed fields */
796 if (TYPE_FIELD_BITSIZE (arg_type, fieldno))
798 v = value_from_longest (type,
799 unpack_field_as_long (arg_type,
800 VALUE_CONTENTS (arg1)
803 VALUE_BITPOS (v) = TYPE_FIELD_BITPOS (arg_type, fieldno) % 8;
804 VALUE_BITSIZE (v) = TYPE_FIELD_BITSIZE (arg_type, fieldno);
806 else if (fieldno < TYPE_N_BASECLASSES (arg_type))
808 /* This field is actually a base subobject, so preserve the
809 entire object's contents for later references to virtual
811 v = allocate_value (VALUE_ENCLOSING_TYPE (arg1));
812 VALUE_TYPE (v) = arg_type;
813 if (VALUE_LAZY (arg1))
816 memcpy (VALUE_CONTENTS_ALL_RAW (v), VALUE_CONTENTS_ALL_RAW (arg1),
817 TYPE_LENGTH (VALUE_ENCLOSING_TYPE (arg1)));
818 VALUE_OFFSET (v) = VALUE_OFFSET (arg1);
819 VALUE_EMBEDDED_OFFSET (v)
821 VALUE_EMBEDDED_OFFSET (arg1) +
822 TYPE_FIELD_BITPOS (arg_type, fieldno) / 8;
826 /* Plain old data member */
827 offset += TYPE_FIELD_BITPOS (arg_type, fieldno) / 8;
828 v = allocate_value (type);
829 if (VALUE_LAZY (arg1))
832 memcpy (VALUE_CONTENTS_RAW (v),
833 VALUE_CONTENTS_RAW (arg1) + offset,
835 VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset;
837 VALUE_LVAL (v) = VALUE_LVAL (arg1);
838 if (VALUE_LVAL (arg1) == lval_internalvar)
839 VALUE_LVAL (v) = lval_internalvar_component;
840 VALUE_ADDRESS (v) = VALUE_ADDRESS (arg1);
841 /* VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset
842 + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; */
846 /* Given a value ARG1 of a struct or union type,
847 extract and return the value of one of its (non-static) fields.
848 FIELDNO says which field. */
851 value_field (arg1, fieldno)
852 register value_ptr arg1;
853 register int fieldno;
855 return value_primitive_field (arg1, 0, fieldno, VALUE_TYPE (arg1));
858 /* Return a non-virtual function as a value.
859 F is the list of member functions which contains the desired method.
860 J is an index into F which provides the desired method. */
863 value_fn_field (arg1p, f, j, type, offset)
870 register value_ptr v;
871 register struct type *ftype = TYPE_FN_FIELD_TYPE (f, j);
874 sym = lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f, j),
875 0, VAR_NAMESPACE, 0, NULL);
879 error ("Internal error: could not find physical method named %s",
880 TYPE_FN_FIELD_PHYSNAME (f, j));
883 v = allocate_value (ftype);
884 VALUE_ADDRESS (v) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym));
885 VALUE_TYPE (v) = ftype;
889 if (type != VALUE_TYPE (*arg1p))
890 *arg1p = value_ind (value_cast (lookup_pointer_type (type),
891 value_addr (*arg1p)));
893 /* Move the `this' pointer according to the offset.
894 VALUE_OFFSET (*arg1p) += offset;
901 /* Return a virtual function as a value.
902 ARG1 is the object which provides the virtual function
903 table pointer. *ARG1P is side-effected in calling this function.
904 F is the list of member functions which contains the desired virtual
906 J is an index into F which provides the desired virtual function.
908 TYPE is the type in which F is located. */
910 value_virtual_fn_field (arg1p, f, j, type, offset)
917 value_ptr arg1 = *arg1p;
918 struct type *type1 = check_typedef (VALUE_TYPE (arg1));
920 if (TYPE_HAS_VTABLE (type))
922 /* Deal with HP/Taligent runtime model for virtual functions */
924 value_ptr argp; /* arg1 cast to base */
925 CORE_ADDR vfunc_addr; /* address of virtual method */
926 CORE_ADDR coreptr; /* pointer to target address */
927 int class_index; /* which class segment pointer to use */
928 struct type *ftype = TYPE_FN_FIELD_TYPE (f, j); /* method type */
930 argp = value_cast (type, *arg1p);
932 if (VALUE_ADDRESS (argp) == 0)
933 error ("Address of object is null; object may not have been created.");
935 /* pai: FIXME -- 32x64 possible problem? */
936 /* First word (4 bytes) in object layout is the vtable pointer */
937 coreptr = *(CORE_ADDR *) (VALUE_CONTENTS (argp)); /* pai: (temp) */
938 /* + offset + VALUE_EMBEDDED_OFFSET (argp)); */
941 error ("Virtual table pointer is null for object; object may not have been created.");
944 * FIXME: The code here currently handles only
945 * the non-RRBC case of the Taligent/HP runtime spec; when RRBC
946 * is introduced, the condition for the "if" below will have to
947 * be changed to be a test for the RRBC case. */
951 /* Non-RRBC case; the virtual function pointers are stored at fixed
952 * offsets in the virtual table. */
954 /* Retrieve the offset in the virtual table from the debug
955 * info. The offset of the vfunc's entry is in words from
956 * the beginning of the vtable; but first we have to adjust
957 * by HP_ACC_VFUNC_START to account for other entries */
959 /* pai: FIXME: 32x64 problem here, a word may be 8 bytes in
960 * which case the multiplier should be 8 and values should be long */
961 vp = value_at (builtin_type_int,
962 coreptr + 4 * (TYPE_FN_FIELD_VOFFSET (f, j) + HP_ACC_VFUNC_START), NULL);
964 coreptr = *(CORE_ADDR *) (VALUE_CONTENTS (vp));
965 /* coreptr now contains the address of the virtual function */
966 /* (Actually, it contains the pointer to the plabel for the function. */
970 /* RRBC case; the virtual function pointers are found by double
971 * indirection through the class segment tables. */
973 /* Choose class segment depending on type we were passed */
974 class_index = class_index_in_primary_list (type);
976 /* Find class segment pointer. These are in the vtable slots after
977 * some other entries, so adjust by HP_ACC_VFUNC_START for that. */
978 /* pai: FIXME 32x64 problem here, if words are 8 bytes long
979 * the multiplier below has to be 8 and value should be long. */
980 vp = value_at (builtin_type_int,
981 coreptr + 4 * (HP_ACC_VFUNC_START + class_index), NULL);
982 /* Indirect once more, offset by function index */
983 /* pai: FIXME 32x64 problem here, again multiplier could be 8 and value long */
984 coreptr = *(CORE_ADDR *) (VALUE_CONTENTS (vp) + 4 * TYPE_FN_FIELD_VOFFSET (f, j));
985 vp = value_at (builtin_type_int, coreptr, NULL);
986 coreptr = *(CORE_ADDR *) (VALUE_CONTENTS (vp));
988 /* coreptr now contains the address of the virtual function */
989 /* (Actually, it contains the pointer to the plabel for the function.) */
994 error ("Address of virtual function is null; error in virtual table?");
996 /* Wrap this addr in a value and return pointer */
997 vp = allocate_value (ftype);
998 VALUE_TYPE (vp) = ftype;
999 VALUE_ADDRESS (vp) = coreptr;
1001 /* pai: (temp) do we need the value_ind stuff in value_fn_field? */
1005 { /* Not using HP/Taligent runtime conventions; so try to
1006 * use g++ conventions for virtual table */
1008 struct type *entry_type;
1009 /* First, get the virtual function table pointer. That comes
1010 with a strange type, so cast it to type `pointer to long' (which
1011 should serve just fine as a function type). Then, index into
1012 the table, and convert final value to appropriate function type. */
1013 value_ptr entry, vfn, vtbl;
1014 value_ptr vi = value_from_longest (builtin_type_int,
1015 (LONGEST) TYPE_FN_FIELD_VOFFSET (f, j));
1016 struct type *fcontext = TYPE_FN_FIELD_FCONTEXT (f, j);
1017 struct type *context;
1018 if (fcontext == NULL)
1019 /* We don't have an fcontext (e.g. the program was compiled with
1020 g++ version 1). Try to get the vtbl from the TYPE_VPTR_BASETYPE.
1021 This won't work right for multiple inheritance, but at least we
1022 should do as well as GDB 3.x did. */
1023 fcontext = TYPE_VPTR_BASETYPE (type);
1024 context = lookup_pointer_type (fcontext);
1025 /* Now context is a pointer to the basetype containing the vtbl. */
1026 if (TYPE_TARGET_TYPE (context) != type1)
1028 value_ptr tmp = value_cast (context, value_addr (arg1));
1029 VALUE_POINTED_TO_OFFSET (tmp) = 0;
1030 arg1 = value_ind (tmp);
1031 type1 = check_typedef (VALUE_TYPE (arg1));
1035 /* Now context is the basetype containing the vtbl. */
1037 /* This type may have been defined before its virtual function table
1038 was. If so, fill in the virtual function table entry for the
1040 if (TYPE_VPTR_FIELDNO (context) < 0)
1041 fill_in_vptr_fieldno (context);
1043 /* The virtual function table is now an array of structures
1044 which have the form { int16 offset, delta; void *pfn; }. */
1045 vtbl = value_primitive_field (arg1, 0, TYPE_VPTR_FIELDNO (context),
1046 TYPE_VPTR_BASETYPE (context));
1048 /* With older versions of g++, the vtbl field pointed to an array
1049 of structures. Nowadays it points directly to the structure. */
1050 if (TYPE_CODE (VALUE_TYPE (vtbl)) == TYPE_CODE_PTR
1051 && TYPE_CODE (TYPE_TARGET_TYPE (VALUE_TYPE (vtbl))) == TYPE_CODE_ARRAY)
1053 /* Handle the case where the vtbl field points to an
1054 array of structures. */
1055 vtbl = value_ind (vtbl);
1057 /* Index into the virtual function table. This is hard-coded because
1058 looking up a field is not cheap, and it may be important to save
1059 time, e.g. if the user has set a conditional breakpoint calling
1060 a virtual function. */
1061 entry = value_subscript (vtbl, vi);
1065 /* Handle the case where the vtbl field points directly to a structure. */
1066 vtbl = value_add (vtbl, vi);
1067 entry = value_ind (vtbl);
1070 entry_type = check_typedef (VALUE_TYPE (entry));
1072 if (TYPE_CODE (entry_type) == TYPE_CODE_STRUCT)
1074 /* Move the `this' pointer according to the virtual function table. */
1075 VALUE_OFFSET (arg1) += value_as_long (value_field (entry, 0));
1077 if (!VALUE_LAZY (arg1))
1079 VALUE_LAZY (arg1) = 1;
1080 value_fetch_lazy (arg1);
1083 vfn = value_field (entry, 2);
1085 else if (TYPE_CODE (entry_type) == TYPE_CODE_PTR)
1088 error ("I'm confused: virtual function table has bad type");
1089 /* Reinstantiate the function pointer with the correct type. */
1090 VALUE_TYPE (vfn) = lookup_pointer_type (TYPE_FN_FIELD_TYPE (f, j));
1097 /* ARG is a pointer to an object we know to be at least
1098 a DTYPE. BTYPE is the most derived basetype that has
1099 already been searched (and need not be searched again).
1100 After looking at the vtables between BTYPE and DTYPE,
1101 return the most derived type we find. The caller must
1102 be satisfied when the return value == DTYPE.
1104 FIXME-tiemann: should work with dossier entries as well. */
1107 value_headof (in_arg, btype, dtype)
1109 struct type *btype, *dtype;
1111 /* First collect the vtables we must look at for this object. */
1112 /* FIXME-tiemann: right now, just look at top-most vtable. */
1113 value_ptr arg, vtbl, entry, best_entry = 0;
1115 int offset, best_offset = 0;
1117 CORE_ADDR pc_for_sym;
1118 char *demangled_name;
1119 struct minimal_symbol *msymbol;
1121 btype = TYPE_VPTR_BASETYPE (dtype);
1122 CHECK_TYPEDEF (btype);
1125 arg = value_cast (lookup_pointer_type (btype), arg);
1126 vtbl = value_ind (value_field (value_ind (arg), TYPE_VPTR_FIELDNO (btype)));
1128 /* Check that VTBL looks like it points to a virtual function table. */
1129 msymbol = lookup_minimal_symbol_by_pc (VALUE_ADDRESS (vtbl));
1131 || (demangled_name = SYMBOL_NAME (msymbol)) == NULL
1132 || !VTBL_PREFIX_P (demangled_name))
1134 /* If we expected to find a vtable, but did not, let the user
1135 know that we aren't happy, but don't throw an error.
1136 FIXME: there has to be a better way to do this. */
1137 struct type *error_type = (struct type *) xmalloc (sizeof (struct type));
1138 memcpy (error_type, VALUE_TYPE (in_arg), sizeof (struct type));
1139 TYPE_NAME (error_type) = savestring ("suspicious *", sizeof ("suspicious *"));
1140 VALUE_TYPE (in_arg) = error_type;
1144 /* Now search through the virtual function table. */
1145 entry = value_ind (vtbl);
1146 nelems = longest_to_int (value_as_long (value_field (entry, 2)));
1147 for (i = 1; i <= nelems; i++)
1149 entry = value_subscript (vtbl, value_from_longest (builtin_type_int,
1151 /* This won't work if we're using thunks. */
1152 if (TYPE_CODE (check_typedef (VALUE_TYPE (entry))) != TYPE_CODE_STRUCT)
1154 offset = longest_to_int (value_as_long (value_field (entry, 0)));
1155 /* If we use '<=' we can handle single inheritance
1156 * where all offsets are zero - just use the first entry found. */
1157 if (offset <= best_offset)
1159 best_offset = offset;
1163 /* Move the pointer according to BEST_ENTRY's offset, and figure
1164 out what type we should return as the new pointer. */
1165 if (best_entry == 0)
1167 /* An alternative method (which should no longer be necessary).
1168 * But we leave it in for future use, when we will hopefully
1169 * have optimizes the vtable to use thunks instead of offsets. */
1170 /* Use the name of vtable itself to extract a base type. */
1171 demangled_name += 4; /* Skip _vt$ prefix. */
1175 pc_for_sym = value_as_pointer (value_field (best_entry, 2));
1176 sym = find_pc_function (pc_for_sym);
1177 demangled_name = cplus_demangle (SYMBOL_NAME (sym), DMGL_ANSI);
1178 *(strchr (demangled_name, ':')) = '\0';
1180 sym = lookup_symbol (demangled_name, 0, VAR_NAMESPACE, 0, 0);
1182 error ("could not find type declaration for `%s'", demangled_name);
1185 free (demangled_name);
1186 arg = value_add (value_cast (builtin_type_int, arg),
1187 value_field (best_entry, 0));
1191 VALUE_TYPE (arg) = lookup_pointer_type (SYMBOL_TYPE (sym));
1195 /* ARG is a pointer object of type TYPE. If TYPE has virtual
1196 function tables, probe ARG's tables (including the vtables
1197 of its baseclasses) to figure out the most derived type that ARG
1198 could actually be a pointer to. */
1201 value_from_vtable_info (arg, type)
1205 /* Take care of preliminaries. */
1206 if (TYPE_VPTR_FIELDNO (type) < 0)
1207 fill_in_vptr_fieldno (type);
1208 if (TYPE_VPTR_FIELDNO (type) < 0)
1211 return value_headof (arg, 0, type);
1214 /* Return true if the INDEXth field of TYPE is a virtual baseclass
1215 pointer which is for the base class whose type is BASECLASS. */
1218 vb_match (type, index, basetype)
1221 struct type *basetype;
1223 struct type *fieldtype;
1224 char *name = TYPE_FIELD_NAME (type, index);
1225 char *field_class_name = NULL;
1229 /* gcc 2.4 uses _vb$. */
1230 if (name[1] == 'v' && name[2] == 'b' && is_cplus_marker (name[3]))
1231 field_class_name = name + 4;
1232 /* gcc 2.5 will use __vb_. */
1233 if (name[1] == '_' && name[2] == 'v' && name[3] == 'b' && name[4] == '_')
1234 field_class_name = name + 5;
1236 if (field_class_name == NULL)
1237 /* This field is not a virtual base class pointer. */
1240 /* It's a virtual baseclass pointer, now we just need to find out whether
1241 it is for this baseclass. */
1242 fieldtype = TYPE_FIELD_TYPE (type, index);
1243 if (fieldtype == NULL
1244 || TYPE_CODE (fieldtype) != TYPE_CODE_PTR)
1245 /* "Can't happen". */
1248 /* What we check for is that either the types are equal (needed for
1249 nameless types) or have the same name. This is ugly, and a more
1250 elegant solution should be devised (which would probably just push
1251 the ugliness into symbol reading unless we change the stabs format). */
1252 if (TYPE_TARGET_TYPE (fieldtype) == basetype)
1255 if (TYPE_NAME (basetype) != NULL
1256 && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype)) != NULL
1257 && STREQ (TYPE_NAME (basetype),
1258 TYPE_NAME (TYPE_TARGET_TYPE (fieldtype))))
1263 /* Compute the offset of the baseclass which is
1264 the INDEXth baseclass of class TYPE,
1265 for value at VALADDR (in host) at ADDRESS (in target).
1266 The result is the offset of the baseclass value relative
1267 to (the address of)(ARG) + OFFSET.
1269 -1 is returned on error. */
1272 baseclass_offset (type, index, valaddr, address)
1278 struct type *basetype = TYPE_BASECLASS (type, index);
1280 if (BASETYPE_VIA_VIRTUAL (type, index))
1282 /* Must hunt for the pointer to this virtual baseclass. */
1283 register int i, len = TYPE_NFIELDS (type);
1284 register int n_baseclasses = TYPE_N_BASECLASSES (type);
1286 /* First look for the virtual baseclass pointer
1288 for (i = n_baseclasses; i < len; i++)
1290 if (vb_match (type, i, basetype))
1293 = unpack_pointer (TYPE_FIELD_TYPE (type, i),
1294 valaddr + (TYPE_FIELD_BITPOS (type, i) / 8));
1296 return addr - (LONGEST) address;
1299 /* Not in the fields, so try looking through the baseclasses. */
1300 for (i = index + 1; i < n_baseclasses; i++)
1303 baseclass_offset (type, i, valaddr, address);
1311 /* Baseclass is easily computed. */
1312 return TYPE_BASECLASS_BITPOS (type, index) / 8;
1315 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
1318 Extracting bits depends on endianness of the machine. Compute the
1319 number of least significant bits to discard. For big endian machines,
1320 we compute the total number of bits in the anonymous object, subtract
1321 off the bit count from the MSB of the object to the MSB of the
1322 bitfield, then the size of the bitfield, which leaves the LSB discard
1323 count. For little endian machines, the discard count is simply the
1324 number of bits from the LSB of the anonymous object to the LSB of the
1327 If the field is signed, we also do sign extension. */
1330 unpack_field_as_long (type, valaddr, fieldno)
1337 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
1338 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
1340 struct type *field_type;
1342 val = extract_unsigned_integer (valaddr + bitpos / 8, sizeof (val));
1343 field_type = TYPE_FIELD_TYPE (type, fieldno);
1344 CHECK_TYPEDEF (field_type);
1346 /* Extract bits. See comment above. */
1348 if (BITS_BIG_ENDIAN)
1349 lsbcount = (sizeof val * 8 - bitpos % 8 - bitsize);
1351 lsbcount = (bitpos % 8);
1354 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
1355 If the field is signed, and is negative, then sign extend. */
1357 if ((bitsize > 0) && (bitsize < 8 * (int) sizeof (val)))
1359 valmask = (((ULONGEST) 1) << bitsize) - 1;
1361 if (!TYPE_UNSIGNED (field_type))
1363 if (val & (valmask ^ (valmask >> 1)))
1372 /* Modify the value of a bitfield. ADDR points to a block of memory in
1373 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
1374 is the desired value of the field, in host byte order. BITPOS and BITSIZE
1375 indicate which bits (in target bit order) comprise the bitfield. */
1378 modify_field (addr, fieldval, bitpos, bitsize)
1381 int bitpos, bitsize;
1385 /* If a negative fieldval fits in the field in question, chop
1386 off the sign extension bits. */
1387 if (bitsize < (8 * (int) sizeof (fieldval))
1388 && (~fieldval & ~((1 << (bitsize - 1)) - 1)) == 0)
1389 fieldval = fieldval & ((1 << bitsize) - 1);
1391 /* Warn if value is too big to fit in the field in question. */
1392 if (bitsize < (8 * (int) sizeof (fieldval))
1393 && 0 != (fieldval & ~((1 << bitsize) - 1)))
1395 /* FIXME: would like to include fieldval in the message, but
1396 we don't have a sprintf_longest. */
1397 warning ("Value does not fit in %d bits.", bitsize);
1399 /* Truncate it, otherwise adjoining fields may be corrupted. */
1400 fieldval = fieldval & ((1 << bitsize) - 1);
1403 oword = extract_signed_integer (addr, sizeof oword);
1405 /* Shifting for bit field depends on endianness of the target machine. */
1406 if (BITS_BIG_ENDIAN)
1407 bitpos = sizeof (oword) * 8 - bitpos - bitsize;
1409 /* Mask out old value, while avoiding shifts >= size of oword */
1410 if (bitsize < 8 * (int) sizeof (oword))
1411 oword &= ~(((((ULONGEST) 1) << bitsize) - 1) << bitpos);
1413 oword &= ~((~(ULONGEST) 0) << bitpos);
1414 oword |= fieldval << bitpos;
1416 store_signed_integer (addr, sizeof oword, oword);
1419 /* Convert C numbers into newly allocated values */
1422 value_from_longest (type, num)
1424 register LONGEST num;
1426 register value_ptr val = allocate_value (type);
1427 register enum type_code code;
1430 code = TYPE_CODE (type);
1431 len = TYPE_LENGTH (type);
1435 case TYPE_CODE_TYPEDEF:
1436 type = check_typedef (type);
1439 case TYPE_CODE_CHAR:
1440 case TYPE_CODE_ENUM:
1441 case TYPE_CODE_BOOL:
1442 case TYPE_CODE_RANGE:
1443 store_signed_integer (VALUE_CONTENTS_RAW (val), len, num);
1448 /* This assumes that all pointers of a given length
1449 have the same form. */
1450 store_address (VALUE_CONTENTS_RAW (val), len, (CORE_ADDR) num);
1454 error ("Unexpected type (%d) encountered for integer constant.", code);
1459 /* Create a value for a string constant to be stored locally
1460 (not in the inferior's memory space, but in GDB memory).
1461 This is analogous to value_from_longest, which also does not
1462 use inferior memory. String shall NOT contain embedded nulls. */
1465 value_from_string (ptr)
1469 int len = strlen (ptr);
1470 int lowbound = current_language->string_lower_bound;
1471 struct type *rangetype =
1472 create_range_type ((struct type *) NULL,
1474 lowbound, len + lowbound - 1);
1475 struct type *stringtype =
1476 create_array_type ((struct type *) NULL,
1477 *current_language->string_char_type,
1480 val = allocate_value (stringtype);
1481 memcpy (VALUE_CONTENTS_RAW (val), ptr, len);
1486 value_from_double (type, num)
1490 register value_ptr val = allocate_value (type);
1491 struct type *base_type = check_typedef (type);
1492 register enum type_code code = TYPE_CODE (base_type);
1493 register int len = TYPE_LENGTH (base_type);
1495 if (code == TYPE_CODE_FLT)
1497 store_floating (VALUE_CONTENTS_RAW (val), len, num);
1500 error ("Unexpected type encountered for floating constant.");
1505 /* Deal with the value that is "about to be returned". */
1507 /* Return the value that a function returning now
1508 would be returning to its caller, assuming its type is VALTYPE.
1509 RETBUF is where we look for what ought to be the contents
1510 of the registers (in raw form). This is because it is often
1511 desirable to restore old values to those registers
1512 after saving the contents of interest, and then call
1513 this function using the saved values.
1514 struct_return is non-zero when the function in question is
1515 using the structure return conventions on the machine in question;
1516 0 when it is using the value returning conventions (this often
1517 means returning pointer to where structure is vs. returning value). */
1520 value_being_returned (valtype, retbuf, struct_return)
1521 register struct type *valtype;
1526 register value_ptr val;
1529 /* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */
1530 if (EXTRACT_STRUCT_VALUE_ADDRESS_P)
1533 addr = EXTRACT_STRUCT_VALUE_ADDRESS (retbuf);
1535 error ("Function return value unknown");
1536 return value_at (valtype, addr, NULL);
1539 val = allocate_value (valtype);
1540 CHECK_TYPEDEF (valtype);
1541 EXTRACT_RETURN_VALUE (valtype, retbuf, VALUE_CONTENTS_RAW (val));
1546 /* Should we use EXTRACT_STRUCT_VALUE_ADDRESS instead of
1547 EXTRACT_RETURN_VALUE? GCC_P is true if compiled with gcc
1548 and TYPE is the type (which is known to be struct, union or array).
1550 On most machines, the struct convention is used unless we are
1551 using gcc and the type is of a special size. */
1552 /* As of about 31 Mar 93, GCC was changed to be compatible with the
1553 native compiler. GCC 2.3.3 was the last release that did it the
1554 old way. Since gcc2_compiled was not changed, we have no
1555 way to correctly win in all cases, so we just do the right thing
1556 for gcc1 and for gcc2 after this change. Thus it loses for gcc
1557 2.0-2.3.3. This is somewhat unfortunate, but changing gcc2_compiled
1558 would cause more chaos than dealing with some struct returns being
1562 generic_use_struct_convention (gcc_p, value_type)
1564 struct type *value_type;
1566 return !((gcc_p == 1)
1567 && (TYPE_LENGTH (value_type) == 1
1568 || TYPE_LENGTH (value_type) == 2
1569 || TYPE_LENGTH (value_type) == 4
1570 || TYPE_LENGTH (value_type) == 8));
1573 #ifndef USE_STRUCT_CONVENTION
1574 #define USE_STRUCT_CONVENTION(gcc_p,type) generic_use_struct_convention (gcc_p, type)
1577 /* Some fundamental types (such as long double) are returned on the stack for
1578 certain architectures. This macro should return true for any type besides
1579 struct, union or array that gets returned on the stack. */
1581 #ifndef RETURN_VALUE_ON_STACK
1582 #define RETURN_VALUE_ON_STACK(TYPE) 0
1585 /* Return true if the function specified is using the structure returning
1586 convention on this machine to return arguments, or 0 if it is using
1587 the value returning convention. FUNCTION is the value representing
1588 the function, FUNCADDR is the address of the function, and VALUE_TYPE
1589 is the type returned by the function. GCC_P is nonzero if compiled
1593 using_struct_return (function, funcaddr, value_type, gcc_p)
1596 struct type *value_type;
1600 register enum type_code code = TYPE_CODE (value_type);
1602 if (code == TYPE_CODE_ERROR)
1603 error ("Function return type unknown.");
1605 if (code == TYPE_CODE_STRUCT
1606 || code == TYPE_CODE_UNION
1607 || code == TYPE_CODE_ARRAY
1608 || RETURN_VALUE_ON_STACK (value_type))
1609 return USE_STRUCT_CONVENTION (gcc_p, value_type);
1614 /* Store VAL so it will be returned if a function returns now.
1615 Does not verify that VAL's type matches what the current
1616 function wants to return. */
1619 set_return_value (val)
1622 struct type *type = check_typedef (VALUE_TYPE (val));
1623 register enum type_code code = TYPE_CODE (type);
1625 if (code == TYPE_CODE_ERROR)
1626 error ("Function return type unknown.");
1628 if (code == TYPE_CODE_STRUCT
1629 || code == TYPE_CODE_UNION) /* FIXME, implement struct return. */
1630 error ("GDB does not support specifying a struct or union return value.");
1632 STORE_RETURN_VALUE (type, VALUE_CONTENTS (val));
1636 _initialize_values ()
1638 add_cmd ("convenience", no_class, show_convenience,
1639 "Debugger convenience (\"$foo\") variables.\n\
1640 These variables are created when you assign them values;\n\
1641 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\n\
1642 A few convenience variables are given values automatically:\n\
1643 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
1644 \"$__\" holds the contents of the last address examined with \"x\".",
1647 add_cmd ("values", no_class, show_values,
1648 "Elements of value history around item number IDX (or last ten).",