gdb/frame.h

   1 /* Definitions for dealing with stack frames, for GDB, the GNU debugger.
   2
   3    Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1996,
   4    1997, 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #if !defined (FRAME_H)
  24 #define FRAME_H 1
  25
  26 /* The frame object.  */
  27
  28 struct frame_info;
  29
  30 /* The frame object's ID.  This provides a per-frame unique identifier
  31    that can be used to relocate a `struct frame_info' after a target
  32    resume or a frame cache destruct (assuming the target hasn't
  33    unwound the stack past that frame - a problem handled elsewhere).  */
  34
  35 struct frame_id
  36 {
  37   /* The frame's address.  This should be constant through out the
  38      lifetime of a frame.  */
  39   /* NOTE: cagney/2002-11-16: The ia64 has two stacks and hence two
  40      frame bases.  This will need to be expanded to accomodate that.  */
  41   CORE_ADDR base;
  42   /* The frame's current PC.  While the PC within the function may
  43      change, the function that contains the PC does not.  Should this
  44      instead be the frame's function?  */
  45   CORE_ADDR pc;
  46 };
  47
  48 /* For every stopped thread, GDB tracks two frames: current and
  49    selected.  Current frame is the inner most frame of the selected
  50    thread.  Selected frame is the frame currently being examined via
  51    the GDB CLI (selected using `up', `down', ...).  The frames are
  52    created on-demand (via get_prev_frame()) and then held in a frame
  53    cache.  Provide mechanims for controlling these frames.  */
  54 /* FIXME: cagney/2002-11-14: At any time, only one thread's selected
  55    and current frame can be active.  Switching threads causes gdb to
  56    discard all that cached frame information.  Ulgh!  Instead, current
  57    and selected frame should be bound to a thread.  */
  58
  59 extern struct frame_info *selected_frame;
  60 extern void select_frame (struct frame_info *);
  61 extern void set_current_frame (struct frame_info *);
  62 extern struct frame_info *get_current_frame (void);
  63
  64 /* Invalidates the frame cache.  */
  65 extern void flush_cached_frames (void);
  66
  67 /* Flushes the frame cache and then selects the inner most (aka
  68    current) frame - it changes selected frame.  */
  69 /* FIXME: cagney/2002-11-14: Should this re-select the selected frame
  70    from before the flush?  */
  71 extern void reinit_frame_cache (void);
  72
  73 /* Given a FRAME, return the next (more inner, younger) or previous
  74    (more outer, older) frame.  */
  75 extern struct frame_info *get_prev_frame (struct frame_info *);
  76 extern struct frame_info *get_next_frame (struct frame_info *);
  77
  78 /* Given a frame's ID, relocate the frame.  Returns NULL if the frame
  79    is not found.  */
  80 extern struct frame_info *frame_find_by_id (struct frame_id id);
  81
  82 /* Base attributes of a frame: */
  83
  84 /* The frame's `resume' address.  Where the program will resume in
  85    this frame.  */
  86 extern CORE_ADDR get_frame_pc (struct frame_info *);
  87
  88 /* Return the frame address from FI.  Except in the machine-dependent
  89    *FRAME* macros, a frame address has no defined meaning other than
  90    as a magic cookie which identifies a frame over calls to the
  91    inferior (um, SEE NOTE BELOW).  The only known exception is
  92    inferior.h (PC_IN_CALL_DUMMY) [ON_STACK]; see comments there.  You
  93    cannot assume that a frame address contains enough information to
  94    reconstruct the frame; if you want more than just to identify the
  95    frame (e.g. be able to fetch variables relative to that frame),
  96    then save the whole struct frame_info (and the next struct
  97    frame_info, since the latter is used for fetching variables on some
  98    machines) (um, again SEE NOTE BELOW).
  99
 100    NOTE: cagney/2002-11-18: Actually, the frame address isn't
 101    sufficient for identifying a frame, and the counter examples are
 102    wrong!
 103
 104    Code that needs to (re)identify a frame must use get_frame_id() and
 105    frame_find_by_id() (and in the future, a frame_compare() function
 106    instead of INNER_THAN()).  Two reasons: an architecture (e.g.,
 107    ia64) can have more than one frame address (due to multiple stack
 108    pointers) (frame ID is going to be expanded to accomodate this);
 109    successive frameless function calls can only be differientated by
 110    comparing both the frame's base and the frame's enclosing function
 111    (frame_find_by_id() is going to be modified to perform this test).
 112
 113    The generic dummy frame version of PC_IN_CALL_DUMMY() is able to
 114    identify a dummy frame using only the PC value.  So the frame
 115    address is not needed.  In fact, most PC_IN_CALL_DUMMY() calls now
 116    pass zero as the frame/sp values as the caller knows that those
 117    values won't be used.  Once all architectures are using generic
 118    dummy frames, PC_IN_CALL_DUMMY() can drop the sp/frame parameters.
 119    When it comes to finding a dummy frame, the next frame's frame ID
 120    (with out duing an unwind) can be used (ok, could if it wasn't for
 121    the need to change the way the PPC defined frame base in a strange
 122    way).
 123
 124    Modern architectures should be using something like dwarf2's
 125    location expression to describe where a variable lives.  Such
 126    expressions specify their own debug info centric frame address.
 127    Consequently, a generic frame address is pretty meaningless.  */
 128
 129 extern CORE_ADDR get_frame_base (struct frame_info *);
 130
 131 /* Return the per-frame unique identifer.  Can be used to relocate a
 132    frame after a frame cache flush (and other similar operations).  */
 133 extern void get_frame_id (struct frame_info *fi, struct frame_id *id);
 134
 135 /* The frame's level: 0 for innermost, 1 for its caller, ...; or -1
 136    for an invalid frame).  */
 137 extern int frame_relative_level (struct frame_info *fi);
 138
 139 /* Return the frame's type.  Some are real, some are signal
 140    trampolines, and some are completly artificial (dummy).  */
 141
 142 enum frame_type
 143 {
 144   /* A true stack frame, created by the target program during normal
 145      execution.  */
 146   NORMAL_FRAME,
 147   /* A fake frame, created by GDB when performing an inferior function
 148      call.  */
 149   DUMMY_FRAME,
 150   /* In a signal handler, various OSs handle this in various ways.
 151      The main thing is that the frame may be far from normal.  */
 152   SIGTRAMP_FRAME
 153 };
 154 extern enum frame_type get_frame_type (struct frame_info *);
 155
 156 /* FIXME: cagney/2002-11-10: Some targets want to directly mark a
 157    frame as being of a specific type.  This shouldn't be necessary.
 158    PC_IN_SIGTRAMP() indicates a SIGTRAMP_FRAME and PC_IN_CALL_DUMMY()
 159    indicates a DUMMY_FRAME.  I suspect the real problem here is that
 160    get_prev_frame() only sets initialized after INIT_EXTRA_FRAME_INFO
 161    as been called.  Consequently, some targets found that the frame's
 162    type was wrong and tried to fix it.  The correct fix is to modify
 163    get_prev_frame() so that it initializes the frame's type before
 164    calling any other functions.  */
 165 extern void deprecated_set_frame_type (struct frame_info *,
 166                                        enum frame_type type);
 167
 168 /* Unwind the stack frame so that the value of REGNUM, in the previous
 169    (up, older) frame is returned.  If VALUEP is NULL, don't
 170    fetch/compute the value.  Instead just return the location of the
 171    value.  */
 172 extern void frame_register_unwind (struct frame_info *frame, int regnum,
 173                                    int *optimizedp, enum lval_type *lvalp,
 174                                    CORE_ADDR *addrp, int *realnump,
 175                                    void *valuep);
 176
 177 /* More convenient interface to frame_register_unwind().  */
 178 /* NOTE: cagney/2002-09-13: Return void as one day these functions may
 179    be changed to return an indication that the read succeeded.  */
 180
 181 extern void frame_unwind_signed_register (struct frame_info *frame,
 182                                           int regnum, LONGEST *val);
 183
 184 extern void frame_unwind_unsigned_register (struct frame_info *frame,
 185                                             int regnum, ULONGEST *val);
 186
 187 /* Get the value of the register that belongs to this FRAME.  This
 188    function is a wrapper to the call sequence ``frame_unwind_register
 189    (get_next_frame (FRAME))''.  As per frame_register_unwind(), if
 190    VALUEP is NULL, the registers value is not fetched/computed.  */
 191
 192 extern void frame_register (struct frame_info *frame, int regnum,
 193                             int *optimizedp, enum lval_type *lvalp,
 194                             CORE_ADDR *addrp, int *realnump,
 195                             void *valuep);
 196
 197 /* More convenient interface to frame_register().  */
 198 /* NOTE: cagney/2002-09-13: Return void as one day these functions may
 199    be changed to return an indication that the read succeeded.  */
 200
 201 extern void frame_read_signed_register (struct frame_info *frame,
 202                                         int regnum, LONGEST *val);
 203
 204 extern void frame_read_unsigned_register (struct frame_info *frame,
 205                                           int regnum, ULONGEST *val);
 206
 207 /* Map between a frame register number and its name.  A frame register
 208    space is a superset of the cooked register space --- it also
 209    includes builtin registers.  */
 210
 211 extern int frame_map_name_to_regnum (const char *name, int strlen);
 212 extern const char *frame_map_regnum_to_name (int regnum);
 213
 214 /* Unwind the PC.  Strictly speaking return the resume address of the
 215    calling frame.  For GDB, `pc' is the resume address and not a
 216    specific register.  */
 217
 218 extern CORE_ADDR frame_pc_unwind (struct frame_info *frame);
 219
 220 \f
 221 /* Return the location (and possibly value) of REGNUM for the previous
 222    (older, up) frame.  All parameters except VALUEP can be assumed to
 223    be non NULL.  When VALUEP is NULL, just the location of the
 224    register should be returned.
 225
 226    UNWIND_CACHE is provided as mechanism for implementing a per-frame
 227    local cache.  It's initial value being NULL.  Memory for that cache
 228    should be allocated using frame_obstack_alloc().
 229
 230    Register window architectures (eg SPARC) should note that REGNUM
 231    identifies the register for the previous frame.  For instance, a
 232    request for the value of "o1" for the previous frame would be found
 233    in the register "i1" in this FRAME.  */
 234
 235 typedef void (frame_register_unwind_ftype) (struct frame_info *frame,
 236                                             void **unwind_cache,
 237                                             int regnum,
 238                                             int *optimized,
 239                                             enum lval_type *lvalp,
 240                                             CORE_ADDR *addrp,
 241                                             int *realnump,
 242                                             void *valuep);
 243
 244 /* Same as for registers above, but return the address at which the
 245    calling frame would resume.  */
 246
 247 typedef CORE_ADDR (frame_pc_unwind_ftype) (struct frame_info *frame,
 248                                            void **unwind_cache);
 249
 250 /* Describe the saved registers of a frame.  */
 251
 252 #if defined (EXTRA_FRAME_INFO) || defined (FRAME_FIND_SAVED_REGS)
 253 /* XXXX - deprecated */
 254 struct frame_saved_regs
 255   {
 256     /* For each register R (except the SP), regs[R] is the address at
 257        which it was saved on entry to the frame, or zero if it was not
 258        saved on entry to this frame.  This includes special registers
 259        such as pc and fp saved in special ways in the stack frame.
 260
 261        regs[SP_REGNUM] is different.  It holds the actual SP, not the
 262        address at which it was saved.  */
 263
 264     CORE_ADDR regs[NUM_REGS];
 265   };
 266 #endif
 267
 268 /* We keep a cache of stack frames, each of which is a "struct
 269    frame_info".  The innermost one gets allocated (in
 270    wait_for_inferior) each time the inferior stops; current_frame
 271    points to it.  Additional frames get allocated (in
 272    get_prev_frame) as needed, and are chained through the next
 273    and prev fields.  Any time that the frame cache becomes invalid
 274    (most notably when we execute something, but also if we change how
 275    we interpret the frames (e.g. "set heuristic-fence-post" in
 276    mips-tdep.c, or anything which reads new symbols)), we should call
 277    reinit_frame_cache.  */
 278
 279 struct frame_info
 280   {
 281     /* Nominal address of the frame described.  See comments at
 282        get_frame_base() about what this means outside the *FRAME*
 283        macros; in the *FRAME* macros, it can mean whatever makes most
 284        sense for this machine.  */
 285     CORE_ADDR frame;
 286
 287     /* Address at which execution is occurring in this frame.
 288        For the innermost frame, it's the current pc.
 289        For other frames, it is a pc saved in the next frame.  */
 290     CORE_ADDR pc;
 291
 292     /* Level of this frame.  The inner-most (youngest) frame is at
 293        level 0.  As you move towards the outer-most (oldest) frame,
 294        the level increases.  This is a cached value.  It could just as
 295        easily be computed by counting back from the selected frame to
 296        the inner most frame.  */
 297     /* NOTE: cagney/2002-04-05: Perhaphs a level of ``-1'' should be
 298        reserved to indicate a bogus frame - one that has been created
 299        just to keep GDB happy (GDB always needs a frame).  For the
 300        moment leave this as speculation.  */
 301     int level;
 302
 303     /* The frame's type.  */
 304     enum frame_type type;
 305
 306     /* For each register, address of where it was saved on entry to
 307        the frame, or zero if it was not saved on entry to this frame.
 308        This includes special registers such as pc and fp saved in
 309        special ways in the stack frame.  The SP_REGNUM is even more
 310        special, the address here is the sp for the previous frame, not
 311        the address where the sp was saved.  */
 312     /* Allocated by frame_saved_regs_zalloc () which is called /
 313        initialized by FRAME_INIT_SAVED_REGS(). */
 314     CORE_ADDR *saved_regs;      /*NUM_REGS + NUM_PSEUDO_REGS*/
 315
 316 #ifdef EXTRA_FRAME_INFO
 317     /* XXXX - deprecated */
 318     /* Anything extra for this structure that may have been defined
 319        in the machine dependent files. */
 320       EXTRA_FRAME_INFO
 321 #endif
 322
 323     /* Anything extra for this structure that may have been defined
 324        in the machine dependent files. */
 325     /* Allocated by frame_obstack_alloc () which is called /
 326        initialized by INIT_EXTRA_FRAME_INFO */
 327     struct frame_extra_info *extra_info;
 328
 329     /* If dwarf2 unwind frame informations is used, this structure holds all
 330        related unwind data.  */
 331     struct context *context;
 332
 333     /* Unwind cache shared between the unwind functions - they had
 334        better all agree as to the contents.  */
 335     void *unwind_cache;
 336
 337     /* See description above.  The previous frame's registers.  */
 338     frame_register_unwind_ftype *register_unwind;
 339
 340     /* See description above.  The previous frame's resume address.
 341        Save the previous PC in a local cache.  */
 342     frame_pc_unwind_ftype *pc_unwind;
 343     int pc_unwind_cache_p;
 344     CORE_ADDR pc_unwind_cache;
 345
 346     /* Pointers to the next (down, inner, younger) and previous (up,
 347        outer, older) frame_info's in the frame cache.  */
 348     struct frame_info *next; /* down, inner, younger */
 349     int prev_p;
 350     struct frame_info *prev; /* up, outer, older */
 351   };
 352
 353 /* Values for the source flag to be used in print_frame_info_base(). */
 354 enum print_what
 355   {
 356     /* Print only the source line, like in stepi. */
 357     SRC_LINE = -1,
 358     /* Print only the location, i.e. level, address (sometimes)
 359        function, args, file, line, line num. */
 360     LOCATION,
 361     /* Print both of the above. */
 362     SRC_AND_LOC,
 363     /* Print location only, but always include the address. */
 364     LOC_AND_ADDRESS
 365   };
 366
 367 /* Allocate additional space for appendices to a struct frame_info.
 368    NOTE: Much of GDB's code works on the assumption that the allocated
 369    saved_regs[] array is the size specified below.  If you try to make
 370    that array smaller, GDB will happily walk off its end. */
 371
 372 #ifdef SIZEOF_FRAME_SAVED_REGS
 373 #error "SIZEOF_FRAME_SAVED_REGS can not be re-defined"
 374 #endif
 375 #define SIZEOF_FRAME_SAVED_REGS \
 376         (sizeof (CORE_ADDR) * (NUM_REGS+NUM_PSEUDO_REGS))
 377
 378 extern void *frame_obstack_alloc (unsigned long size);
 379 extern void frame_saved_regs_zalloc (struct frame_info *);
 380
 381 /* Define a default FRAME_CHAIN_VALID, in the form that is suitable for most
 382    targets.  If FRAME_CHAIN_VALID returns zero it means that the given frame
 383    is the outermost one and has no caller.
 384
 385    XXXX - both default and alternate frame_chain_valid functions are
 386    deprecated.  New code should use dummy frames and one of the
 387    generic functions. */
 388
 389 extern int file_frame_chain_valid (CORE_ADDR, struct frame_info *);
 390 extern int func_frame_chain_valid (CORE_ADDR, struct frame_info *);
 391 extern int nonnull_frame_chain_valid (CORE_ADDR, struct frame_info *);
 392 extern int generic_file_frame_chain_valid (CORE_ADDR, struct frame_info *);
 393 extern int generic_func_frame_chain_valid (CORE_ADDR, struct frame_info *);
 394 extern void generic_save_dummy_frame_tos (CORE_ADDR sp);
 395
 396 extern struct frame_info *create_new_frame (CORE_ADDR, CORE_ADDR);
 397
 398
 399 #ifdef FRAME_FIND_SAVED_REGS
 400 /* XXX - deprecated */
 401 #define FRAME_INIT_SAVED_REGS(FI) get_frame_saved_regs (FI, NULL)
 402 extern void get_frame_saved_regs (struct frame_info *,
 403                                   struct frame_saved_regs *);
 404 #endif
 405
 406 extern struct block *get_frame_block (struct frame_info *,
 407                                       CORE_ADDR *addr_in_block);
 408
 409 extern struct block *get_current_block (CORE_ADDR *addr_in_block);
 410
 411 extern struct block *get_selected_block (CORE_ADDR *addr_in_block);
 412
 413 extern struct symbol *get_frame_function (struct frame_info *);
 414
 415 extern CORE_ADDR frame_address_in_block (struct frame_info *);
 416
 417 extern CORE_ADDR get_pc_function_start (CORE_ADDR);
 418
 419 extern struct block *block_for_pc (CORE_ADDR);
 420
 421 extern struct block *block_for_pc_sect (CORE_ADDR, asection *);
 422
 423 extern int frameless_look_for_prologue (struct frame_info *);
 424
 425 extern void print_frame_args (struct symbol *, struct frame_info *,
 426                               int, struct ui_file *);
 427
 428 extern struct frame_info *find_relative_frame (struct frame_info *, int *);
 429
 430 extern void show_and_print_stack_frame (struct frame_info *fi, int level,
 431                                         int source);
 432
 433 extern void print_stack_frame (struct frame_info *, int, int);
 434
 435 extern void print_only_stack_frame (struct frame_info *, int, int);
 436
 437 extern void show_stack_frame (struct frame_info *);
 438
 439 extern void print_frame_info (struct frame_info *, int, int, int);
 440
 441 extern void show_frame_info (struct frame_info *, int, int, int);
 442
 443 extern struct frame_info *block_innermost_frame (struct block *);
 444
 445 /* NOTE: cagney/2002-09-13: There is no need for this function.
 446    Instead either of frame_unwind_signed_register() or
 447    frame_unwind_unsigned_register() can be used.  */
 448 extern CORE_ADDR deprecated_read_register_dummy (CORE_ADDR pc,
 449                                                  CORE_ADDR fp, int);
 450 extern void generic_push_dummy_frame (void);
 451 extern void generic_pop_current_frame (void (*)(struct frame_info *));
 452 extern void generic_pop_dummy_frame (void);
 453
 454 extern int generic_pc_in_call_dummy (CORE_ADDR pc,
 455                                      CORE_ADDR sp, CORE_ADDR fp);
 456
 457 /* NOTE: cagney/2002-06-26: Targets should no longer use this
 458    function.  Instead, the contents of a dummy frames registers can be
 459    obtained by applying: frame_register_unwind to the dummy frame; or
 460    get_saved_register to the next outer frame.  */
 461
 462 extern char *deprecated_generic_find_dummy_frame (CORE_ADDR pc, CORE_ADDR fp);
 463
 464 extern void generic_fix_call_dummy (char *dummy, CORE_ADDR pc, CORE_ADDR fun,
 465                                     int nargs, struct value **args,
 466                                     struct type *type, int gcc_p);
 467
 468 /* The function generic_get_saved_register() has been made obsolete.
 469    GET_SAVED_REGISTER now defaults to the recursive equivalent -
 470    generic_unwind_get_saved_register() - so there is no need to even
 471    set GET_SAVED_REGISTER.  Architectures that need to override the
 472    register unwind mechanism should modify frame->unwind().  */
 473 extern void deprecated_generic_get_saved_register (char *, int *, CORE_ADDR *,
 474                                                    struct frame_info *, int,
 475                                                    enum lval_type *);
 476
 477 extern void generic_save_call_dummy_addr (CORE_ADDR lo, CORE_ADDR hi);
 478
 479 extern void get_saved_register (char *raw_buffer, int *optimized,
 480                                 CORE_ADDR * addrp,
 481                                 struct frame_info *frame,
 482                                 int regnum, enum lval_type *lval);
 483
 484 extern int frame_register_read (struct frame_info *frame, int regnum,
 485                                 void *buf);
 486
 487 /* From stack.c.  */
 488 extern void args_info (char *, int);
 489
 490 extern void locals_info (char *, int);
 491
 492 extern void (*selected_frame_level_changed_hook) (int);
 493
 494 extern void return_command (char *, int);
 495
 496 #endif /* !defined (FRAME_H)  */