1/* Definitions for values of C expressions, for GDB.
2
3   Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
4   1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003
5   Free Software Foundation, Inc.
6
7   This file is part of GDB.
8
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.
13
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.
18
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.  */
23
24#if !defined (VALUE_H)
25#define VALUE_H 1
26
27#include "doublest.h"
28#include "frame.h"		/* For struct frame_id.  */
29
30struct block;
31struct expression;
32struct regcache;
33struct symbol;
34struct type;
35struct ui_file;
36
37/* The structure which defines the type of a value.  It should never
38   be possible for a program lval value to survive over a call to the
39   inferior (i.e. to be put into the history list or an internal
40   variable).  */
41
42struct value
43{
44  /* Type of value; either not an lval, or one of the various
45     different possible kinds of lval.  */
46  enum lval_type lval;
47
48  /* Is it modifiable?  Only relevant if lval != not_lval.  */
49  int modifiable;
50
51  /* Location of value (if lval).  */
52  union
53  {
54    /* If lval == lval_memory, this is the address in the inferior.
55       If lval == lval_register, this is the byte offset into the
56       registers structure.  */
57    CORE_ADDR address;
58
59    /* Pointer to internal variable.  */
60    struct internalvar *internalvar;
61
62    /* Number of register.  Only used with lval_reg_frame_relative.  */
63    int regnum;
64  } location;
65
66  /* Describes offset of a value within lval of a structure in bytes.
67     If lval == lval_memory, this is an offset to the address.
68     If lval == lval_register, this is a further offset from
69     location.address within the registers structure.
70     Note also the member embedded_offset below.  */
71  int offset;
72
73  /* Only used for bitfields; number of bits contained in them.  */
74  int bitsize;
75
76  /* Only used for bitfields; position of start of field.
77     For BITS_BIG_ENDIAN=0 targets, it is the position of the LSB.
78     For BITS_BIG_ENDIAN=1 targets, it is the position of the MSB. */
79    int bitpos;
80
81  /* Frame value is relative to.  In practice, this ID is only used if
82     the value is stored in several registers in other than the
83     current frame, and these registers have not all been saved at the
84     same place in memory.  This will be described in the lval enum
85     above as "lval_reg_frame_relative".  */
86  struct frame_id frame_id;
87
88  /* Type of the value.  */
89  struct type *type;
90
91  /* If a value represents a C++ object, then the `type' field gives
92     the object's compile-time type.  If the object actually belongs
93     to some class derived from `type', perhaps with other base
94     classes and additional members, then `type' is just a subobject
95     of the real thing, and the full object is probably larger than
96     `type' would suggest.
97
98     If `type' is a dynamic class (i.e. one with a vtable), then GDB
99     can actually determine the object's run-time type by looking at
100     the run-time type information in the vtable.  When this
101     information is available, we may elect to read in the entire
102     object, for several reasons:
103
104     - When printing the value, the user would probably rather see the
105       full object, not just the limited portion apparent from the
106       compile-time type.
107
108     - If `type' has virtual base classes, then even printing `type'
109       alone may require reaching outside the `type' portion of the
110       object to wherever the virtual base class has been stored.
111
112     When we store the entire object, `enclosing_type' is the run-time
113     type -- the complete object -- and `embedded_offset' is the
114     offset of `type' within that larger type, in bytes.  The
115     VALUE_CONTENTS macro takes `embedded_offset' into account, so
116     most GDB code continues to see the `type' portion of the value,
117     just as the inferior would.
118
119     If `type' is a pointer to an object, then `enclosing_type' is a
120     pointer to the object's run-time type, and `pointed_to_offset' is
121     the offset in bytes from the full object to the pointed-to object
122     -- that is, the value `embedded_offset' would have if we
123     followed the pointer and fetched the complete object.  (I don't
124     really see the point.  Why not just determine the run-time type
125     when you indirect, and avoid the special case?  The contents
126     don't matter until you indirect anyway.)
127
128     If we're not doing anything fancy, `enclosing_type' is equal to
129     `type', and `embedded_offset' is zero, so everything works
130     normally.  */
131    struct type *enclosing_type;
132    int embedded_offset;
133    int pointed_to_offset;
134
135    /* Values are stored in a chain, so that they can be deleted
136       easily over calls to the inferior.  Values assigned to internal
137       variables or put into the value history are taken off this
138       list.  */
139    struct value *next;
140
141    /* Register number if the value is from a register.  */
142    short regno;
143
144    /* If zero, contents of this value are in the contents field.  If
145       nonzero, contents are in inferior memory at address in the
146       location.address field plus the offset field (and the lval
147       field should be lval_memory).
148
149       WARNING: This field is used by the code which handles
150       watchpoints (see breakpoint.c) to decide whether a particular
151       value can be watched by hardware watchpoints.  If the lazy flag
152       is set for some member of a value chain, it is assumed that
153       this member of the chain doesn't need to be watched as part of
154       watching the value itself.  This is how GDB avoids watching the
155       entire struct or array when the user wants to watch a single
156       struct member or array element.  If you ever change the way
157       lazy flag is set and reset, be sure to consider this use as
158       well!  */
159    char lazy;
160
161    /* If nonzero, this is the value of a variable which does not
162       actually exist in the program.  */
163    char optimized_out;
164
165    /* The BFD section associated with this value.  */
166    asection *bfd_section;
167
168    /* If value is a variable, is it initialized or not.  */
169    int initialized;
170
171    /* Actual contents of the value.  For use of this value; setting
172       it uses the stuff above.  Not valid if lazy is nonzero.
173       Target byte-order.  We force it to be aligned properly for any
174       possible value.  Note that a value therefore extends beyond
175       what is declared here.  */
176    union
177    {
178      long contents[1];
179      DOUBLEST force_doublest_align;
180      LONGEST force_longest_align;
181      CORE_ADDR force_core_addr_align;
182      void *force_pointer_align;
183    } aligner;
184    /* Do not add any new members here -- contents above will trash them.  */
185};
186
187#define VALUE_TYPE(val) (val)->type
188#define VALUE_ENCLOSING_TYPE(val) (val)->enclosing_type
189#define VALUE_LAZY(val) (val)->lazy
190
191/* VALUE_CONTENTS and VALUE_CONTENTS_RAW both return the address of
192   the gdb buffer used to hold a copy of the contents of the lval.
193   VALUE_CONTENTS is used when the contents of the buffer are needed
194   -- it uses value_fetch_lazy() to load the buffer from the process
195   being debugged if it hasn't already been loaded.
196   VALUE_CONTENTS_RAW is used when data is being stored into the
197   buffer, or when it is certain that the contents of the buffer are
198   valid.
199
200   Note: The contents pointer is adjusted by the offset required to
201   get to the real subobject, if the value happens to represent
202   something embedded in a larger run-time object.  */
203
204#define VALUE_CONTENTS_RAW(val) \
205 ((char *) (val)->aligner.contents + (val)->embedded_offset)
206#define VALUE_CONTENTS(val) \
207 ((void)(VALUE_LAZY(val) && value_fetch_lazy(val)), VALUE_CONTENTS_RAW(val))
208
209/* The ALL variants of the above two macros do not adjust the returned
210   pointer by the embedded_offset value.  */
211
212#define VALUE_CONTENTS_ALL_RAW(val) ((char *) (val)->aligner.contents)
213#define VALUE_CONTENTS_ALL(val) \
214  ((void) (VALUE_LAZY(val) && value_fetch_lazy(val)), \
215   VALUE_CONTENTS_ALL_RAW(val))
216
217extern int value_fetch_lazy (struct value *val);
218
219#define VALUE_LVAL(val) (val)->lval
220#define VALUE_ADDRESS(val) (val)->location.address
221#define VALUE_INTERNALVAR(val) (val)->location.internalvar
222#define VALUE_FRAME_REGNUM(val) ((val)->location.regnum)
223#define VALUE_FRAME_ID(val) ((val)->frame_id)
224#define VALUE_OFFSET(val) (val)->offset
225#define VALUE_BITSIZE(val) (val)->bitsize
226#define VALUE_BITPOS(val) (val)->bitpos
227#define VALUE_NEXT(val) (val)->next
228#define VALUE_REGNO(val) (val)->regno
229#define VALUE_OPTIMIZED_OUT(val) ((val)->optimized_out)
230#define VALUE_EMBEDDED_OFFSET(val) ((val)->embedded_offset)
231#define VALUE_POINTED_TO_OFFSET(val) ((val)->pointed_to_offset)
232#define VALUE_BFD_SECTION(val) ((val)->bfd_section)
233
234/* Convert a REF to the object referenced.  */
235
236#define COERCE_REF(arg) \
237  do {									\
238    struct type *value_type_arg_tmp = check_typedef (VALUE_TYPE (arg));	\
239    if (TYPE_CODE (value_type_arg_tmp) == TYPE_CODE_REF)		\
240      arg = value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp),	\
241                           unpack_pointer (VALUE_TYPE (arg),		\
242                                           VALUE_CONTENTS (arg)),	\
243			                   VALUE_BFD_SECTION (arg));	\
244  } while (0)
245
246/* If ARG is an array, convert it to a pointer.
247   If ARG is an enum, convert it to an integer.
248   If ARG is a function, convert it to a function pointer.
249
250   References are dereferenced.  */
251
252#define COERCE_ARRAY(arg) \
253  do {									\
254    COERCE_REF(arg);							\
255    if (current_language->c_style_arrays				\
256        && TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_ARRAY)		\
257      arg = value_coerce_array (arg);					\
258    if (TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_FUNC)			\
259      arg = value_coerce_function (arg);				\
260  } while (0)
261
262#define COERCE_NUMBER(arg) \
263  do { COERCE_ARRAY(arg); COERCE_ENUM(arg); } while (0)
264
265/* NOTE: cagney/2002-12-17: This macro was handling a chill language
266   problem but that language has gone away.  */
267#define COERCE_VARYING_ARRAY(arg, real_arg_type)
268
269/* If ARG is an enum, convert it to an integer.  */
270
271#define COERCE_ENUM(arg) \
272  do {									\
273    if (TYPE_CODE (check_typedef (VALUE_TYPE (arg))) == TYPE_CODE_ENUM)	\
274      arg = value_cast (builtin_type_unsigned_int, arg);		\
275  } while (0)
276
277/* Internal variables (variables for convenience of use of debugger)
278   are recorded as a chain of these structures.  */
279
280struct internalvar
281{
282  struct internalvar *next;
283  char *name;
284  struct value *value;
285};
286
287/* Pointer to member function.  Depends on compiler implementation.  */
288
289#define METHOD_PTR_IS_VIRTUAL(ADDR)  ((ADDR) & 0x80000000)
290#define METHOD_PTR_FROM_VOFFSET(OFFSET) (0x80000000 + (OFFSET))
291#define METHOD_PTR_TO_VOFFSET(ADDR) (~0x80000000 & (ADDR))
292
293
294#include "symtab.h"
295#include "gdbtypes.h"
296#include "expression.h"
297
298struct frame_info;
299struct fn_field;
300
301extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
302
303extern LONGEST value_as_long (struct value *val);
304extern DOUBLEST value_as_double (struct value *val);
305extern CORE_ADDR value_as_address (struct value *val);
306
307extern LONGEST unpack_long (struct type *type, const char *valaddr);
308extern DOUBLEST unpack_double (struct type *type, const char *valaddr,
309			       int *invp);
310extern CORE_ADDR unpack_pointer (struct type *type, const char *valaddr);
311extern LONGEST unpack_field_as_long (struct type *type, const char *valaddr,
312				     int fieldno);
313
314extern struct value *value_from_longest (struct type *type, LONGEST num);
315extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
316extern struct value *value_from_double (struct type *type, DOUBLEST num);
317extern struct value *value_from_string (char *string);
318
319extern struct value *value_at (struct type *type, CORE_ADDR addr,
320			       asection * sect);
321extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr,
322				    asection * sect);
323
324extern struct value *value_from_register (struct type *type, int regnum,
325					  struct frame_info *frame);
326
327extern struct value *value_of_variable (struct symbol *var, struct block *b);
328
329extern struct value *value_of_register (int regnum,
330					struct frame_info *frame);
331
332extern int symbol_read_needs_frame (struct symbol *);
333
334extern struct value *read_var_value (struct symbol *var,
335				     struct frame_info *frame);
336
337extern struct value *locate_var_value (struct symbol *var,
338				       struct frame_info *frame);
339
340extern struct value *allocate_value (struct type *type);
341
342extern struct value *allocate_repeat_value (struct type *type, int count);
343
344extern struct value *value_change_enclosing_type (struct value *val,
345						  struct type *new_type);
346
347extern struct value *value_mark (void);
348
349extern void value_free_to_mark (struct value *mark);
350
351extern struct value *value_string (char *ptr, int len);
352extern struct value *value_bitstring (char *ptr, int len);
353
354extern struct value *value_array (int lowbound, int highbound,
355				  struct value ** elemvec);
356
357extern struct value *value_concat (struct value *arg1, struct value *arg2);
358
359extern struct value *value_binop (struct value *arg1, struct value *arg2,
360				  enum exp_opcode op);
361
362extern struct value *value_add (struct value *arg1, struct value *arg2);
363
364extern struct value *value_sub (struct value *arg1, struct value *arg2);
365
366extern struct value *value_coerce_array (struct value *arg1);
367
368extern struct value *value_coerce_function (struct value *arg1);
369
370extern struct value *value_ind (struct value *arg1);
371
372extern struct value *value_addr (struct value *arg1);
373
374extern struct value *value_assign (struct value *toval, struct value *fromval);
375
376extern struct value *value_neg (struct value *arg1);
377
378extern struct value *value_complement (struct value *arg1);
379
380extern struct value *value_struct_elt (struct value **argp,
381				       struct value **args,
382				       char *name, int *static_memfuncp,
383				       char *err);
384
385extern struct value *value_aggregate_elt (struct type *curtype,
386					  char *name,
387					  enum noside noside);
388
389extern struct value *value_static_field (struct type *type, int fieldno);
390
391extern struct fn_field *value_find_oload_method_list (struct value **, char *,
392						      int, int *,
393						      struct type **, int *);
394
395extern int find_overload_match (struct type **arg_types, int nargs,
396				char *name, int method, int lax,
397				struct value **objp, struct symbol *fsym,
398				struct value **valp, struct symbol **symp,
399				int *staticp);
400
401extern struct value *value_field (struct value *arg1, int fieldno);
402
403extern struct value *value_primitive_field (struct value *arg1, int offset,
404					    int fieldno,
405					    struct type *arg_type);
406
407
408extern struct type *value_rtti_target_type (struct value *, int *, int *,
409					    int *);
410
411extern struct value *value_full_object (struct value *, struct type *, int,
412					int, int);
413
414extern struct value *value_cast (struct type *type, struct value *arg2);
415
416extern struct value *value_zero (struct type *type, enum lval_type lv);
417
418extern struct value *value_repeat (struct value *arg1, int count);
419
420extern struct value *value_subscript (struct value *array, struct value *idx);
421
422extern struct value *register_value_being_returned (struct type *valtype,
423						    struct regcache *retbuf);
424
425extern struct value *value_in (struct value *element, struct value *set);
426
427extern int value_bit_index (struct type *type, char *addr, int index);
428
429extern int using_struct_return (struct type *value_type, int gcc_p);
430
431extern struct value *evaluate_expression (struct expression *exp);
432
433extern struct value *evaluate_type (struct expression *exp);
434
435extern struct value *evaluate_subexp_with_coercion (struct expression *,
436						    int *, enum noside);
437
438extern struct value *parse_and_eval (char *exp);
439
440extern struct value *parse_to_comma_and_eval (char **expp);
441
442extern struct type *parse_and_eval_type (char *p, int length);
443
444extern CORE_ADDR parse_and_eval_address (char *exp);
445
446extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
447
448extern LONGEST parse_and_eval_long (char *exp);
449
450extern struct value *access_value_history (int num);
451
452extern struct value *value_of_internalvar (struct internalvar *var);
453
454extern void set_internalvar (struct internalvar *var, struct value *val);
455
456extern void set_internalvar_component (struct internalvar *var,
457				       int offset,
458				       int bitpos, int bitsize,
459				       struct value *newvalue);
460
461extern struct internalvar *lookup_internalvar (char *name);
462
463extern int value_equal (struct value *arg1, struct value *arg2);
464
465extern int value_less (struct value *arg1, struct value *arg2);
466
467extern int value_logical_not (struct value *arg1);
468
469/* C++ */
470
471extern struct value *value_of_this (int complain);
472
473extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
474				    enum exp_opcode op,
475				    enum exp_opcode otherop,
476				    enum noside noside);
477
478extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
479				   enum noside noside);
480
481extern struct value *value_fn_field (struct value ** arg1p, struct fn_field *f,
482				     int j, struct type *type, int offset);
483
484extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
485				 struct value *arg2);
486
487extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
488
489extern int destructor_name_p (const char *name, const struct type *type);
490
491#define value_free(val) xfree (val)
492
493extern void free_all_values (void);
494
495extern void release_value (struct value *val);
496
497extern int record_latest_value (struct value *val);
498
499extern void modify_field (char *addr, LONGEST fieldval, int bitpos,
500			  int bitsize);
501
502extern void type_print (struct type * type, char *varstring,
503			struct ui_file * stream, int show);
504
505extern char *baseclass_addr (struct type *type, int index, char *valaddr,
506			     struct value **valuep, int *errp);
507
508extern void print_longest (struct ui_file * stream, int format,
509			   int use_local, LONGEST val);
510
511extern void print_floating (char *valaddr, struct type * type,
512			    struct ui_file * stream);
513
514extern int value_print (struct value *val, struct ui_file *stream, int format,
515			enum val_prettyprint pretty);
516
517extern void value_print_array_elements (struct value *val,
518					struct ui_file *stream, int format,
519					enum val_prettyprint pretty);
520
521extern struct value *value_release_to_mark (struct value *mark);
522
523extern int val_print (struct type * type, char *valaddr,
524		      int embedded_offset, CORE_ADDR address,
525		      struct ui_file * stream, int format,
526		      int deref_ref, int recurse,
527		      enum val_prettyprint pretty);
528
529extern int common_val_print (struct value *val,
530			     struct ui_file *stream, int format,
531			     int deref_ref, int recurse,
532			     enum val_prettyprint pretty);
533
534extern int val_print_string (CORE_ADDR addr, int len, int width, struct ui_file *stream);
535
536extern void print_variable_value (struct symbol * var,
537				  struct frame_info * frame,
538				  struct ui_file *stream);
539
540extern int check_field (struct value *, const char *);
541
542extern void typedef_print (struct type * type, struct symbol * news,
543			     struct ui_file * stream);
544
545extern char *internalvar_name (struct internalvar *var);
546
547extern void clear_value_history (void);
548
549extern void clear_internalvars (void);
550
551/* From values.c */
552
553extern struct value *value_copy (struct value *);
554
555/* From valops.c */
556
557extern struct value *varying_to_slice (struct value *);
558
559extern struct value *value_slice (struct value *, int, int);
560
561extern struct value *value_literal_complex (struct value *, struct value *,
562					    struct type *);
563
564extern void find_rt_vbase_offset (struct type *, struct type *, char *, int,
565				  int *, int *);
566
567extern struct value *find_function_in_inferior (const char *);
568
569extern struct value *value_allocate_space_in_inferior (int);
570
571extern CORE_ADDR legacy_push_arguments (int nargs, struct value ** args,
572					CORE_ADDR sp, int struct_return,
573					CORE_ADDR struct_addr);
574
575extern struct value *value_of_local (const char *name, int complain);
576
577#endif /* !defined (VALUE_H) */
578