gdb/frame.h

   1 /* Definitions for dealing with stack frames, for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1996, 1997,
   4    1998, 1999, 2000, 2001, 2002, 2003, 2004, 2007, 2008, 2009
   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 3 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, see <http://www.gnu.org/licenses/>.  */
  21
  22 #if !defined (FRAME_H)
  23 #define FRAME_H 1
  24
  25 /* The following is the intended naming schema for frame functions.
  26    It isn't 100% consistent, but it is aproaching that.  Frame naming
  27    schema:
  28
  29    Prefixes:
  30
  31    get_frame_WHAT...(): Get WHAT from the THIS frame (functionaly
  32    equivalent to THIS->next->unwind->what)
  33
  34    frame_unwind_WHAT...(): Unwind THIS frame's WHAT from the NEXT
  35    frame.
  36
  37    put_frame_WHAT...(): Put a value into this frame (unsafe, need to
  38    invalidate the frame / regcache afterwards) (better name more
  39    strongly hinting at its unsafeness)
  40
  41    safe_....(): Safer version of various functions, doesn't throw an
  42    error (leave this for later?).  Returns non-zero / non-NULL if the
  43    request succeeds, zero / NULL otherwize.
  44
  45    Suffixes:
  46
  47    void /frame/_WHAT(): Read WHAT's value into the buffer parameter.
  48
  49    ULONGEST /frame/_WHAT_unsigned(): Return an unsigned value (the
  50    alternative is *frame_unsigned_WHAT).
  51
  52    LONGEST /frame/_WHAT_signed(): Return WHAT signed value.
  53
  54    What:
  55
  56    /frame/_memory* (frame, coreaddr, len [, buf]): Extract/return
  57    *memory.
  58
  59    /frame/_register* (frame, regnum [, buf]): extract/return register.
  60
  61    CORE_ADDR /frame/_{pc,sp,...} (frame): Resume address, innner most
  62    stack *address, ...
  63
  64    */
  65
  66 struct symtab_and_line;
  67 struct frame_unwind;
  68 struct frame_base;
  69 struct block;
  70 struct gdbarch;
  71 struct ui_file;
  72
  73 /* The frame object.  */
  74
  75 struct frame_info;
  76
  77 /* The frame object's ID.  This provides a per-frame unique identifier
  78    that can be used to relocate a `struct frame_info' after a target
  79    resume or a frame cache destruct.  It of course assumes that the
  80    inferior hasn't unwound the stack past that frame.  */
  81
  82 struct frame_id
  83 {
  84   /* The frame's stack address.  This shall be constant through out
  85      the lifetime of a frame.  Note that this requirement applies to
  86      not just the function body, but also the prologue and (in theory
  87      at least) the epilogue.  Since that value needs to fall either on
  88      the boundary, or within the frame's address range, the frame's
  89      outer-most address (the inner-most address of the previous frame)
  90      is used.  Watch out for all the legacy targets that still use the
  91      function pointer register or stack pointer register.  They are
  92      wrong.
  93
  94      This field is valid only if stack_addr_p is true.  Otherwise, this
  95      frame represents the null frame.  */
  96   CORE_ADDR stack_addr;
  97
  98   /* The frame's code address.  This shall be constant through out the
  99      lifetime of the frame.  While the PC (a.k.a. resume address)
 100      changes as the function is executed, this code address cannot.
 101      Typically, it is set to the address of the entry point of the
 102      frame's function (as returned by get_frame_func).
 103
 104      This field is valid only if code_addr_p is true.  Otherwise, this
 105      frame is considered to have a wildcard code address, i.e. one that
 106      matches every address value in frame comparisons.  */
 107   CORE_ADDR code_addr;
 108
 109   /* The frame's special address.  This shall be constant through out the
 110      lifetime of the frame.  This is used for architectures that may have
 111      frames that do not change the stack but are still distinct and have
 112      some form of distinct identifier (e.g. the ia64 which uses a 2nd
 113      stack for registers).  This field is treated as unordered - i.e. will
 114      not be used in frame ordering comparisons.
 115
 116      This field is valid only if special_addr_p is true.  Otherwise, this
 117      frame is considered to have a wildcard special address, i.e. one that
 118      matches every address value in frame comparisons.  */
 119   CORE_ADDR special_addr;
 120
 121   /* Flags to indicate the above fields have valid contents.  */
 122   unsigned int stack_addr_p : 1;
 123   unsigned int code_addr_p : 1;
 124   unsigned int special_addr_p : 1;
 125 };
 126
 127 /* Methods for constructing and comparing Frame IDs.  */
 128
 129 /* For convenience.  All fields are zero.  */
 130 extern const struct frame_id null_frame_id;
 131
 132 /* Flag to control debugging.  */
 133
 134 extern int frame_debug;
 135
 136 /* Construct a frame ID.  The first parameter is the frame's constant
 137    stack address (typically the outer-bound), and the second the
 138    frame's constant code address (typically the entry point).
 139    The special identifier address is set to indicate a wild card.  */
 140 extern struct frame_id frame_id_build (CORE_ADDR stack_addr,
 141                                        CORE_ADDR code_addr);
 142
 143 /* Construct a special frame ID.  The first parameter is the frame's constant
 144    stack address (typically the outer-bound), the second is the
 145    frame's constant code address (typically the entry point),
 146    and the third parameter is the frame's special identifier address. */
 147 extern struct frame_id frame_id_build_special (CORE_ADDR stack_addr,
 148                                                CORE_ADDR code_addr,
 149                                                CORE_ADDR special_addr);
 150
 151 /* Construct a wild card frame ID.  The parameter is the frame's constant
 152    stack address (typically the outer-bound).  The code address as well
 153    as the special identifier address are set to indicate wild cards.  */
 154 extern struct frame_id frame_id_build_wild (CORE_ADDR stack_addr);
 155
 156 /* Returns non-zero when L is a valid frame (a valid frame has a
 157    non-zero .base).  */
 158 extern int frame_id_p (struct frame_id l);
 159
 160 /* Returns non-zero when L and R identify the same frame, or, if
 161    either L or R have a zero .func, then the same frame base.  */
 162 extern int frame_id_eq (struct frame_id l, struct frame_id r);
 163
 164 /* Write the internal representation of a frame ID on the specified
 165    stream.  */
 166 extern void fprint_frame_id (struct ui_file *file, struct frame_id id);
 167
 168
 169 /* Frame types.  Some are real, some are signal trampolines, and some
 170    are completely artificial (dummy).  */
 171
 172 enum frame_type
 173 {
 174   /* A true stack frame, created by the target program during normal
 175      execution.  */
 176   NORMAL_FRAME,
 177   /* A fake frame, created by GDB when performing an inferior function
 178      call.  */
 179   DUMMY_FRAME,
 180   /* In a signal handler, various OSs handle this in various ways.
 181      The main thing is that the frame may be far from normal.  */
 182   SIGTRAMP_FRAME,
 183   /* Sentinel or registers frame.  This frame obtains register values
 184      direct from the inferior's registers.  */
 185   SENTINEL_FRAME
 186 };
 187
 188 /* For every stopped thread, GDB tracks two frames: current and
 189    selected.  Current frame is the inner most frame of the selected
 190    thread.  Selected frame is the one being examined by the the GDB
 191    CLI (selected using `up', `down', ...).  The frames are created
 192    on-demand (via get_prev_frame()) and then held in a frame cache.  */
 193 /* FIXME: cagney/2002-11-28: Er, there is a lie here.  If you do the
 194    sequence: `thread 1; up; thread 2; thread 1' you lose thread 1's
 195    selected frame.  At present GDB only tracks the selected frame of
 196    the current thread.  But be warned, that might change.  */
 197 /* FIXME: cagney/2002-11-14: At any time, only one thread's selected
 198    and current frame can be active.  Switching threads causes gdb to
 199    discard all that cached frame information.  Ulgh!  Instead, current
 200    and selected frame should be bound to a thread.  */
 201
 202 /* On demand, create the inner most frame using information found in
 203    the inferior.  If the inner most frame can't be created, throw an
 204    error.  */
 205 extern struct frame_info *get_current_frame (void);
 206
 207 /* Does the current target interface have enough state to be able to
 208    query the current inferior for frame info, and is the inferior in a
 209    state where that is possible?  */
 210 extern int has_stack_frames (void);
 211
 212 /* Invalidates the frame cache (this function should have been called
 213    invalidate_cached_frames).
 214
 215    FIXME: cagney/2002-11-28: There should be two methods: one that
 216    reverts the thread's selected frame back to current frame (for when
 217    the inferior resumes) and one that does not (for when the user
 218    modifies the target invalidating the frame cache).  */
 219 extern void reinit_frame_cache (void);
 220
 221 /* On demand, create the selected frame and then return it.  If the
 222    selected frame can not be created, this function prints then throws
 223    an error.  When MESSAGE is non-NULL, use it for the error message,
 224    otherwize use a generic error message.  */
 225 /* FIXME: cagney/2002-11-28: At present, when there is no selected
 226    frame, this function always returns the current (inner most) frame.
 227    It should instead, when a thread has previously had its frame
 228    selected (but not resumed) and the frame cache invalidated, find
 229    and then return that thread's previously selected frame.  */
 230 extern struct frame_info *get_selected_frame (const char *message);
 231
 232 /* Select a specific frame.  NULL, apparently implies re-select the
 233    inner most frame.  */
 234 extern void select_frame (struct frame_info *);
 235
 236 /* Given a FRAME, return the next (more inner, younger) or previous
 237    (more outer, older) frame.  */
 238 extern struct frame_info *get_prev_frame (struct frame_info *);
 239 extern struct frame_info *get_next_frame (struct frame_info *);
 240
 241 /* Given a frame's ID, relocate the frame.  Returns NULL if the frame
 242    is not found.  */
 243 extern struct frame_info *frame_find_by_id (struct frame_id id);
 244
 245 /* Base attributes of a frame: */
 246
 247 /* The frame's `resume' address.  Where the program will resume in
 248    this frame.
 249
 250    This replaced: frame->pc; */
 251 extern CORE_ADDR get_frame_pc (struct frame_info *);
 252
 253 /* An address (not necessarily aligned to an instruction boundary)
 254    that falls within THIS frame's code block.
 255
 256    When a function call is the last statement in a block, the return
 257    address for the call may land at the start of the next block.
 258    Similarly, if a no-return function call is the last statement in
 259    the function, the return address may end up pointing beyond the
 260    function, and possibly at the start of the next function.
 261
 262    These methods make an allowance for this.  For call frames, this
 263    function returns the frame's PC-1 which "should" be an address in
 264    the frame's block.  */
 265
 266 extern CORE_ADDR get_frame_address_in_block (struct frame_info *this_frame);
 267
 268 /* The frame's inner-most bound.  AKA the stack-pointer.  Confusingly
 269    known as top-of-stack.  */
 270
 271 extern CORE_ADDR get_frame_sp (struct frame_info *);
 272
 273 /* Following on from the `resume' address.  Return the entry point
 274    address of the function containing that resume address, or zero if
 275    that function isn't known.  */
 276 extern CORE_ADDR get_frame_func (struct frame_info *fi);
 277
 278 /* Closely related to the resume address, various symbol table
 279    attributes that are determined by the PC.  Note that for a normal
 280    frame, the PC refers to the resume address after the return, and
 281    not the call instruction.  In such a case, the address is adjusted
 282    so that it (approximately) identifies the call site (and not the
 283    return site).
 284
 285    NOTE: cagney/2002-11-28: The frame cache could be used to cache the
 286    computed value.  Working on the assumption that the bottle-neck is
 287    in the single step code, and that code causes the frame cache to be
 288    constantly flushed, caching things in a frame is probably of little
 289    benefit.  As they say `show us the numbers'.
 290
 291    NOTE: cagney/2002-11-28: Plenty more where this one came from:
 292    find_frame_block(), find_frame_partial_function(),
 293    find_frame_symtab(), find_frame_function().  Each will need to be
 294    carefully considered to determine if the real intent was for it to
 295    apply to the PC or the adjusted PC.  */
 296 extern void find_frame_sal (struct frame_info *frame,
 297                             struct symtab_and_line *sal);
 298
 299 /* Set the current source and line to the location given by frame
 300    FRAME, if possible.  When CENTER is true, adjust so the relevant
 301    line is in the center of the next 'list'.  */
 302
 303 void set_current_sal_from_frame (struct frame_info *, int);
 304
 305 /* Return the frame base (what ever that is) (DEPRECATED).
 306
 307    Old code was trying to use this single method for two conflicting
 308    purposes.  Such code needs to be updated to use either of:
 309
 310    get_frame_id: A low level frame unique identifier, that consists of
 311    both a stack and a function address, that can be used to uniquely
 312    identify a frame.  This value is determined by the frame's
 313    low-level unwinder, the stack part [typically] being the
 314    top-of-stack of the previous frame, and the function part being the
 315    function's start address.  Since the correct identification of a
 316    frameless function requires both the a stack and function address,
 317    the old get_frame_base method was not sufficient.
 318
 319    get_frame_base_address: get_frame_locals_address:
 320    get_frame_args_address: A set of high-level debug-info dependant
 321    addresses that fall within the frame.  These addresses almost
 322    certainly will not match the stack address part of a frame ID (as
 323    returned by get_frame_base).
 324
 325    This replaced: frame->frame; */
 326
 327 extern CORE_ADDR get_frame_base (struct frame_info *);
 328
 329 /* Return the per-frame unique identifer.  Can be used to relocate a
 330    frame after a frame cache flush (and other similar operations).  If
 331    FI is NULL, return the null_frame_id.
 332
 333    NOTE: kettenis/20040508: These functions return a structure.  On
 334    platforms where structures are returned in static storage (vax,
 335    m68k), this may trigger compiler bugs in code like:
 336
 337    if (frame_id_eq (get_frame_id (l), get_frame_id (r)))
 338
 339    where the return value from the first get_frame_id (l) gets
 340    overwritten by the second get_frame_id (r).  Please avoid writing
 341    code like this.  Use code like:
 342
 343    struct frame_id id = get_frame_id (l);
 344    if (frame_id_eq (id, get_frame_id (r)))
 345
 346    instead, since that avoids the bug.  */
 347 extern struct frame_id get_frame_id (struct frame_info *fi);
 348 extern struct frame_id frame_unwind_id (struct frame_info *next_frame);
 349
 350 /* Assuming that a frame is `normal', return its base-address, or 0 if
 351    the information isn't available.  NOTE: This address is really only
 352    meaningful to the frame's high-level debug info.  */
 353 extern CORE_ADDR get_frame_base_address (struct frame_info *);
 354
 355 /* Assuming that a frame is `normal', return the base-address of the
 356    local variables, or 0 if the information isn't available.  NOTE:
 357    This address is really only meaningful to the frame's high-level
 358    debug info.  Typically, the argument and locals share a single
 359    base-address.  */
 360 extern CORE_ADDR get_frame_locals_address (struct frame_info *);
 361
 362 /* Assuming that a frame is `normal', return the base-address of the
 363    parameter list, or 0 if that information isn't available.  NOTE:
 364    This address is really only meaningful to the frame's high-level
 365    debug info.  Typically, the argument and locals share a single
 366    base-address.  */
 367 extern CORE_ADDR get_frame_args_address (struct frame_info *);
 368
 369 /* The frame's level: 0 for innermost, 1 for its caller, ...; or -1
 370    for an invalid frame).  */
 371 extern int frame_relative_level (struct frame_info *fi);
 372
 373 /* Return the frame's type.  */
 374
 375 extern enum frame_type get_frame_type (struct frame_info *);
 376
 377 /* For frames where we can not unwind further, describe why.  */
 378
 379 enum unwind_stop_reason
 380   {
 381     /* No particular reason; either we haven't tried unwinding yet,
 382        or we didn't fail.  */
 383     UNWIND_NO_REASON,
 384
 385     /* The previous frame's analyzer returns an invalid result
 386        from this_id.
 387
 388        FIXME drow/2006-08-16: This is how GDB used to indicate end of
 389        stack.  We should migrate to a model where frames always have a
 390        valid ID, and this becomes not just an error but an internal
 391        error.  But that's a project for another day.  */
 392     UNWIND_NULL_ID,
 393
 394     /* All the conditions after this point are considered errors;
 395        abnormal stack termination.  If a backtrace stops for one
 396        of these reasons, we'll let the user know.  This marker
 397        is not a valid stop reason.  */
 398     UNWIND_FIRST_ERROR,
 399
 400     /* This frame ID looks like it ought to belong to a NEXT frame,
 401        but we got it for a PREV frame.  Normally, this is a sign of
 402        unwinder failure.  It could also indicate stack corruption.  */
 403     UNWIND_INNER_ID,
 404
 405     /* This frame has the same ID as the previous one.  That means
 406        that unwinding further would almost certainly give us another
 407        frame with exactly the same ID, so break the chain.  Normally,
 408        this is a sign of unwinder failure.  It could also indicate
 409        stack corruption.  */
 410     UNWIND_SAME_ID,
 411
 412     /* The frame unwinder didn't find any saved PC, but we needed
 413        one to unwind further.  */
 414     UNWIND_NO_SAVED_PC,
 415   };
 416
 417 /* Return the reason why we can't unwind past this frame.  */
 418
 419 enum unwind_stop_reason get_frame_unwind_stop_reason (struct frame_info *);
 420
 421 /* Translate a reason code to an informative string.  */
 422
 423 const char *frame_stop_reason_string (enum unwind_stop_reason);
 424
 425 /* Unwind the stack frame so that the value of REGNUM, in the previous
 426    (up, older) frame is returned.  If VALUEP is NULL, don't
 427    fetch/compute the value.  Instead just return the location of the
 428    value.  */
 429 extern void frame_register_unwind (struct frame_info *frame, int regnum,
 430                                    int *optimizedp, enum lval_type *lvalp,
 431                                    CORE_ADDR *addrp, int *realnump,
 432                                    gdb_byte *valuep);
 433
 434 /* Fetch a register from this, or unwind a register from the next
 435    frame.  Note that the get_frame methods are wrappers to
 436    frame->next->unwind.  They all [potentially] throw an error if the
 437    fetch fails.  The value methods never return NULL, but usually
 438    do return a lazy value.  */
 439
 440 extern void frame_unwind_register (struct frame_info *frame,
 441                                    int regnum, gdb_byte *buf);
 442 extern void get_frame_register (struct frame_info *frame,
 443                                 int regnum, gdb_byte *buf);
 444
 445 struct value *frame_unwind_register_value (struct frame_info *frame,
 446                                            int regnum);
 447 struct value *get_frame_register_value (struct frame_info *frame,
 448                                         int regnum);
 449
 450 extern LONGEST frame_unwind_register_signed (struct frame_info *frame,
 451                                              int regnum);
 452 extern LONGEST get_frame_register_signed (struct frame_info *frame,
 453                                           int regnum);
 454 extern ULONGEST frame_unwind_register_unsigned (struct frame_info *frame,
 455                                                int regnum);
 456 extern ULONGEST get_frame_register_unsigned (struct frame_info *frame,
 457                                              int regnum);
 458
 459
 460 /* Get the value of the register that belongs to this FRAME.  This
 461    function is a wrapper to the call sequence ``frame_register_unwind
 462    (get_next_frame (FRAME))''.  As per frame_register_unwind(), if
 463    VALUEP is NULL, the registers value is not fetched/computed.  */
 464
 465 extern void frame_register (struct frame_info *frame, int regnum,
 466                             int *optimizedp, enum lval_type *lvalp,
 467                             CORE_ADDR *addrp, int *realnump,
 468                             gdb_byte *valuep);
 469
 470 /* The reverse.  Store a register value relative to the specified
 471    frame.  Note: this call makes the frame's state undefined.  The
 472    register and frame caches must be flushed.  */
 473 extern void put_frame_register (struct frame_info *frame, int regnum,
 474                                 const gdb_byte *buf);
 475
 476 /* Read LEN bytes from one or multiple registers starting with REGNUM
 477    in frame FRAME, starting at OFFSET, into BUF.  */
 478 extern int get_frame_register_bytes (struct frame_info *frame, int regnum,
 479                                      CORE_ADDR offset, int len,
 480                                      gdb_byte *myaddr);
 481
 482 /* Write LEN bytes to one or multiple registers starting with REGNUM
 483    in frame FRAME, starting at OFFSET, into BUF.  */
 484 extern void put_frame_register_bytes (struct frame_info *frame, int regnum,
 485                                       CORE_ADDR offset, int len,
 486                                       const gdb_byte *myaddr);
 487
 488 /* Unwind the PC.  Strictly speaking return the resume address of the
 489    calling frame.  For GDB, `pc' is the resume address and not a
 490    specific register.  */
 491
 492 extern CORE_ADDR frame_pc_unwind (struct frame_info *frame);
 493
 494 /* Discard the specified frame.  Restoring the registers to the state
 495    of the caller.  */
 496 extern void frame_pop (struct frame_info *frame);
 497
 498 /* Return memory from the specified frame.  A frame knows its thread /
 499    LWP and hence can find its way down to a target.  The assumption
 500    here is that the current and previous frame share a common address
 501    space.
 502
 503    If the memory read fails, these methods throw an error.
 504
 505    NOTE: cagney/2003-06-03: Should there be unwind versions of these
 506    methods?  That isn't clear.  Can code, for instance, assume that
 507    this and the previous frame's memory or architecture are identical?
 508    If architecture / memory changes are always separated by special
 509    adaptor frames this should be ok.  */
 510
 511 extern void get_frame_memory (struct frame_info *this_frame, CORE_ADDR addr,
 512                               gdb_byte *buf, int len);
 513 extern LONGEST get_frame_memory_signed (struct frame_info *this_frame,
 514                                         CORE_ADDR memaddr, int len);
 515 extern ULONGEST get_frame_memory_unsigned (struct frame_info *this_frame,
 516                                            CORE_ADDR memaddr, int len);
 517
 518 /* Same as above, but return non-zero when the entire memory read
 519    succeeds, zero otherwize.  */
 520 extern int safe_frame_unwind_memory (struct frame_info *this_frame,
 521                                      CORE_ADDR addr, gdb_byte *buf, int len);
 522
 523 /* Return this frame's architecture.  */
 524
 525 extern struct gdbarch *get_frame_arch (struct frame_info *this_frame);
 526
 527
 528 /* Values for the source flag to be used in print_frame_info_base().  */
 529 enum print_what
 530   {
 531     /* Print only the source line, like in stepi. */
 532     SRC_LINE = -1,
 533     /* Print only the location, i.e. level, address (sometimes)
 534        function, args, file, line, line num. */
 535     LOCATION,
 536     /* Print both of the above. */
 537     SRC_AND_LOC,
 538     /* Print location only, but always include the address. */
 539     LOC_AND_ADDRESS
 540   };
 541
 542 /* Allocate zero initialized memory from the frame cache obstack.
 543    Appendices to the frame info (such as the unwind cache) should
 544    allocate memory using this method.  */
 545
 546 extern void *frame_obstack_zalloc (unsigned long size);
 547 #define FRAME_OBSTACK_ZALLOC(TYPE) ((TYPE *) frame_obstack_zalloc (sizeof (TYPE)))
 548 #define FRAME_OBSTACK_CALLOC(NUMBER,TYPE) ((TYPE *) frame_obstack_zalloc ((NUMBER) * sizeof (TYPE)))
 549
 550 /* Create a regcache, and copy the frame's registers into it.  */
 551 struct regcache *frame_save_as_regcache (struct frame_info *this_frame);
 552
 553 extern struct block *get_frame_block (struct frame_info *,
 554                                       CORE_ADDR *addr_in_block);
 555
 556 /* Return the `struct block' that belongs to the selected thread's
 557    selected frame.  If the inferior has no state, return NULL.
 558
 559    NOTE: cagney/2002-11-29:
 560
 561    No state?  Does the inferior have any execution state (a core file
 562    does, an executable does not).  At present the code tests
 563    `target_has_stack' but I'm left wondering if it should test
 564    `target_has_registers' or, even, a merged target_has_state.
 565
 566    Should it look at the most recently specified SAL?  If the target
 567    has no state, should this function try to extract a block from the
 568    most recently selected SAL?  That way `list foo' would give it some
 569    sort of reference point.  Then again, perhaps that would confuse
 570    things.
 571
 572    Calls to this function can be broken down into two categories: Code
 573    that uses the selected block as an additional, but optional, data
 574    point; Code that uses the selected block as a prop, when it should
 575    have the relevant frame/block/pc explicitly passed in.
 576
 577    The latter can be eliminated by correctly parameterizing the code,
 578    the former though is more interesting.  Per the "address" command,
 579    it occurs in the CLI code and makes it possible for commands to
 580    work, even when the inferior has no state.  */
 581
 582 extern struct block *get_selected_block (CORE_ADDR *addr_in_block);
 583
 584 extern struct symbol *get_frame_function (struct frame_info *);
 585
 586 extern CORE_ADDR get_pc_function_start (CORE_ADDR);
 587
 588 extern struct frame_info *find_relative_frame (struct frame_info *, int *);
 589
 590 extern void show_and_print_stack_frame (struct frame_info *fi, int print_level,
 591                                         enum print_what print_what);
 592
 593 extern void print_stack_frame (struct frame_info *, int print_level,
 594                                enum print_what print_what);
 595
 596 extern void print_frame_info (struct frame_info *, int print_level,
 597                               enum print_what print_what, int args);
 598
 599 extern struct frame_info *block_innermost_frame (struct block *);
 600
 601 extern int deprecated_pc_in_call_dummy (struct gdbarch *gdbarch, CORE_ADDR pc);
 602
 603 /* FIXME: cagney/2003-02-02: Should be deprecated or replaced with a
 604    function called get_frame_register_p().  This slightly weird (and
 605    older) variant of get_frame_register() returns zero (indicating the
 606    register is unavailable) if either: the register isn't cached; or
 607    the register has been optimized out.  Problem is, neither check is
 608    exactly correct.  A register can't be optimized out (it may not
 609    have been saved as part of a function call); The fact that a
 610    register isn't in the register cache doesn't mean that the register
 611    isn't available (it could have been fetched from memory).  */
 612
 613 extern int frame_register_read (struct frame_info *frame, int regnum,
 614                                 gdb_byte *buf);
 615
 616 /* From stack.c.  */
 617 extern void args_info (char *, int);
 618
 619 extern void locals_info (char *, int);
 620
 621 extern void (*deprecated_selected_frame_level_changed_hook) (int);
 622
 623 extern void return_command (char *, int);
 624
 625 /* Set FRAME's unwinder temporarily, so that we can call a sniffer.
 626    Return a cleanup which should be called if unwinding fails, and
 627    discarded if it succeeds.  */
 628
 629 struct cleanup *frame_prepare_for_sniffer (struct frame_info *frame,
 630                                            const struct frame_unwind *unwind);
 631
 632 /* Notes (cagney/2002-11-27, drow/2003-09-06):
 633
 634    You might think that calls to this function can simply be replaced by a
 635    call to get_selected_frame().
 636
 637    Unfortunately, it isn't that easy.
 638
 639    The relevant code needs to be audited to determine if it is
 640    possible (or practical) to instead pass the applicable frame in as a
 641    parameter.  For instance, DEPRECATED_DO_REGISTERS_INFO() relied on
 642    the deprecated_selected_frame global, while its replacement,
 643    PRINT_REGISTERS_INFO(), is parameterized with the selected frame.
 644    The only real exceptions occur at the edge (in the CLI code) where
 645    user commands need to pick up the selected frame before proceeding.
 646
 647    There are also some functions called with a NULL frame meaning either "the
 648    program is not running" or "use the selected frame".
 649
 650    This is important.  GDB is trying to stamp out the hack:
 651
 652    saved_frame = deprecated_safe_get_selected_frame ();
 653    select_frame (...);
 654    hack_using_global_selected_frame ();
 655    select_frame (saved_frame);
 656
 657    Take care!
 658
 659    This function calls get_selected_frame if the inferior should have a
 660    frame, or returns NULL otherwise.  */
 661
 662 extern struct frame_info *deprecated_safe_get_selected_frame (void);
 663
 664 /* Create a frame using the specified BASE and PC.  */
 665
 666 extern struct frame_info *create_new_frame (CORE_ADDR base, CORE_ADDR pc);
 667
 668 #endif /* !defined (FRAME_H)  */