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, 2010, 2011
   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    frame_unwind_caller_WHAT...(): Unwind WHAT for NEXT stack frame's
  38    real caller.  Any inlined functions in NEXT's stack frame are
  39    skipped.  Use these to ignore any potentially inlined functions,
  40    e.g. inlined into the first instruction of a library trampoline.
  41
  42    get_stack_frame_WHAT...(): Get WHAT for THIS frame, but if THIS is
  43    inlined, skip to the containing stack frame.
  44
  45    put_frame_WHAT...(): Put a value into this frame (unsafe, need to
  46    invalidate the frame / regcache afterwards) (better name more
  47    strongly hinting at its unsafeness)
  48
  49    safe_....(): Safer version of various functions, doesn't throw an
  50    error (leave this for later?).  Returns non-zero / non-NULL if the
  51    request succeeds, zero / NULL otherwize.
  52
  53    Suffixes:
  54
  55    void /frame/_WHAT(): Read WHAT's value into the buffer parameter.
  56
  57    ULONGEST /frame/_WHAT_unsigned(): Return an unsigned value (the
  58    alternative is *frame_unsigned_WHAT).
  59
  60    LONGEST /frame/_WHAT_signed(): Return WHAT signed value.
  61
  62    What:
  63
  64    /frame/_memory* (frame, coreaddr, len [, buf]): Extract/return
  65    *memory.
  66
  67    /frame/_register* (frame, regnum [, buf]): extract/return register.
  68
  69    CORE_ADDR /frame/_{pc,sp,...} (frame): Resume address, innner most
  70    stack *address, ...
  71
  72    */
  73
  74 struct symtab_and_line;
  75 struct frame_unwind;
  76 struct frame_base;
  77 struct block;
  78 struct gdbarch;
  79 struct ui_file;
  80
  81 /* The frame object.  */
  82
  83 struct frame_info;
  84
  85 /* The frame object's ID.  This provides a per-frame unique identifier
  86    that can be used to relocate a `struct frame_info' after a target
  87    resume or a frame cache destruct.  It of course assumes that the
  88    inferior hasn't unwound the stack past that frame.  */
  89
  90 struct frame_id
  91 {
  92   /* The frame's stack address.  This shall be constant through out
  93      the lifetime of a frame.  Note that this requirement applies to
  94      not just the function body, but also the prologue and (in theory
  95      at least) the epilogue.  Since that value needs to fall either on
  96      the boundary, or within the frame's address range, the frame's
  97      outer-most address (the inner-most address of the previous frame)
  98      is used.  Watch out for all the legacy targets that still use the
  99      function pointer register or stack pointer register.  They are
 100      wrong.
 101
 102      This field is valid only if stack_addr_p is true.  Otherwise, this
 103      frame represents the null frame.  */
 104   CORE_ADDR stack_addr;
 105
 106   /* The frame's code address.  This shall be constant through out the
 107      lifetime of the frame.  While the PC (a.k.a. resume address)
 108      changes as the function is executed, this code address cannot.
 109      Typically, it is set to the address of the entry point of the
 110      frame's function (as returned by get_frame_func).
 111
 112      For inlined functions (INLINE_DEPTH != 0), this is the address of
 113      the first executed instruction in the block corresponding to the
 114      inlined function.
 115
 116      This field is valid only if code_addr_p is true.  Otherwise, this
 117      frame is considered to have a wildcard code address, i.e. one that
 118      matches every address value in frame comparisons.  */
 119   CORE_ADDR code_addr;
 120
 121   /* The frame's special address.  This shall be constant through out the
 122      lifetime of the frame.  This is used for architectures that may have
 123      frames that do not change the stack but are still distinct and have
 124      some form of distinct identifier (e.g. the ia64 which uses a 2nd
 125      stack for registers).  This field is treated as unordered - i.e. will
 126      not be used in frame ordering comparisons.
 127
 128      This field is valid only if special_addr_p is true.  Otherwise, this
 129      frame is considered to have a wildcard special address, i.e. one that
 130      matches every address value in frame comparisons.  */
 131   CORE_ADDR special_addr;
 132
 133   /* Flags to indicate the above fields have valid contents.  */
 134   unsigned int stack_addr_p : 1;
 135   unsigned int code_addr_p : 1;
 136   unsigned int special_addr_p : 1;
 137
 138   /* The inline depth of this frame.  A frame representing a "called"
 139      inlined function will have this set to a nonzero value.  */
 140   int inline_depth;
 141 };
 142
 143 /* Methods for constructing and comparing Frame IDs.  */
 144
 145 /* For convenience.  All fields are zero.  This means "there is no frame".  */
 146 extern const struct frame_id null_frame_id;
 147
 148 /* This means "there is no frame ID, but there is a frame".  It should be
 149    replaced by best-effort frame IDs for the outermost frame, somehow.
 150    The implementation is only special_addr_p set.  */
 151 extern const struct frame_id outer_frame_id;
 152
 153 /* Flag to control debugging.  */
 154
 155 extern int frame_debug;
 156
 157 /* Construct a frame ID.  The first parameter is the frame's constant
 158    stack address (typically the outer-bound), and the second the
 159    frame's constant code address (typically the entry point).
 160    The special identifier address is set to indicate a wild card.  */
 161 extern struct frame_id frame_id_build (CORE_ADDR stack_addr,
 162                                        CORE_ADDR code_addr);
 163
 164 /* Construct a special frame ID.  The first parameter is the frame's constant
 165    stack address (typically the outer-bound), the second is the
 166    frame's constant code address (typically the entry point),
 167    and the third parameter is the frame's special identifier address.  */
 168 extern struct frame_id frame_id_build_special (CORE_ADDR stack_addr,
 169                                                CORE_ADDR code_addr,
 170                                                CORE_ADDR special_addr);
 171
 172 /* Construct a wild card frame ID.  The parameter is the frame's constant
 173    stack address (typically the outer-bound).  The code address as well
 174    as the special identifier address are set to indicate wild cards.  */
 175 extern struct frame_id frame_id_build_wild (CORE_ADDR stack_addr);
 176
 177 /* Returns non-zero when L is a valid frame (a valid frame has a
 178    non-zero .base).  The outermost frame is valid even without an
 179    ID.  */
 180 extern int frame_id_p (struct frame_id l);
 181
 182 /* Returns non-zero when L is a valid frame representing an inlined
 183    function.  */
 184 extern int frame_id_inlined_p (struct frame_id l);
 185
 186 /* Returns non-zero when L and R identify the same frame, or, if
 187    either L or R have a zero .func, then the same frame base.  */
 188 extern int frame_id_eq (struct frame_id l, struct frame_id r);
 189
 190 /* Write the internal representation of a frame ID on the specified
 191    stream.  */
 192 extern void fprint_frame_id (struct ui_file *file, struct frame_id id);
 193
 194
 195 /* Frame types.  Some are real, some are signal trampolines, and some
 196    are completely artificial (dummy).  */
 197
 198 enum frame_type
 199 {
 200   /* A true stack frame, created by the target program during normal
 201      execution.  */
 202   NORMAL_FRAME,
 203   /* A fake frame, created by GDB when performing an inferior function
 204      call.  */
 205   DUMMY_FRAME,
 206   /* A frame representing an inlined function, associated with an
 207      upcoming (prev, outer, older) NORMAL_FRAME.  */
 208   INLINE_FRAME,
 209   /* In a signal handler, various OSs handle this in various ways.
 210      The main thing is that the frame may be far from normal.  */
 211   SIGTRAMP_FRAME,
 212   /* Fake frame representing a cross-architecture call.  */
 213   ARCH_FRAME,
 214   /* Sentinel or registers frame.  This frame obtains register values
 215      direct from the inferior's registers.  */
 216   SENTINEL_FRAME
 217 };
 218
 219 /* For every stopped thread, GDB tracks two frames: current and
 220    selected.  Current frame is the inner most frame of the selected
 221    thread.  Selected frame is the one being examined by the GDB
 222    CLI (selected using `up', `down', ...).  The frames are created
 223    on-demand (via get_prev_frame()) and then held in a frame cache.  */
 224 /* FIXME: cagney/2002-11-28: Er, there is a lie here.  If you do the
 225    sequence: `thread 1; up; thread 2; thread 1' you lose thread 1's
 226    selected frame.  At present GDB only tracks the selected frame of
 227    the current thread.  But be warned, that might change.  */
 228 /* FIXME: cagney/2002-11-14: At any time, only one thread's selected
 229    and current frame can be active.  Switching threads causes gdb to
 230    discard all that cached frame information.  Ulgh!  Instead, current
 231    and selected frame should be bound to a thread.  */
 232
 233 /* On demand, create the inner most frame using information found in
 234    the inferior.  If the inner most frame can't be created, throw an
 235    error.  */
 236 extern struct frame_info *get_current_frame (void);
 237
 238 /* Does the current target interface have enough state to be able to
 239    query the current inferior for frame info, and is the inferior in a
 240    state where that is possible?  */
 241 extern int has_stack_frames (void);
 242
 243 /* Invalidates the frame cache (this function should have been called
 244    invalidate_cached_frames).
 245
 246    FIXME: cagney/2002-11-28: There should be two methods: one that
 247    reverts the thread's selected frame back to current frame (for when
 248    the inferior resumes) and one that does not (for when the user
 249    modifies the target invalidating the frame cache).  */
 250 extern void reinit_frame_cache (void);
 251
 252 /* On demand, create the selected frame and then return it.  If the
 253    selected frame can not be created, this function prints then throws
 254    an error.  When MESSAGE is non-NULL, use it for the error message,
 255    otherwize use a generic error message.  */
 256 /* FIXME: cagney/2002-11-28: At present, when there is no selected
 257    frame, this function always returns the current (inner most) frame.
 258    It should instead, when a thread has previously had its frame
 259    selected (but not resumed) and the frame cache invalidated, find
 260    and then return that thread's previously selected frame.  */
 261 extern struct frame_info *get_selected_frame (const char *message);
 262
 263 /* If there is a selected frame, return it.  Otherwise, return NULL.  */
 264 extern struct frame_info *get_selected_frame_if_set (void);
 265
 266 /* Select a specific frame.  NULL, apparently implies re-select the
 267    inner most frame.  */
 268 extern void select_frame (struct frame_info *);
 269
 270 /* Given a FRAME, return the next (more inner, younger) or previous
 271    (more outer, older) frame.  */
 272 extern struct frame_info *get_prev_frame (struct frame_info *);
 273 extern struct frame_info *get_next_frame (struct frame_info *);
 274
 275 /* Given a frame's ID, relocate the frame.  Returns NULL if the frame
 276    is not found.  */
 277 extern struct frame_info *frame_find_by_id (struct frame_id id);
 278
 279 /* Base attributes of a frame: */
 280
 281 /* The frame's `resume' address.  Where the program will resume in
 282    this frame.
 283
 284    This replaced: frame->pc; */
 285 extern CORE_ADDR get_frame_pc (struct frame_info *);
 286
 287 /* Same as get_frame_pc, but return a boolean indication of whether
 288    the PC is actually available, instead of throwing an error.  */
 289
 290 extern int get_frame_pc_if_available (struct frame_info *frame,
 291                                       CORE_ADDR *pc);
 292
 293 /* An address (not necessarily aligned to an instruction boundary)
 294    that falls within THIS frame's code block.
 295
 296    When a function call is the last statement in a block, the return
 297    address for the call may land at the start of the next block.
 298    Similarly, if a no-return function call is the last statement in
 299    the function, the return address may end up pointing beyond the
 300    function, and possibly at the start of the next function.
 301
 302    These methods make an allowance for this.  For call frames, this
 303    function returns the frame's PC-1 which "should" be an address in
 304    the frame's block.  */
 305
 306 extern CORE_ADDR get_frame_address_in_block (struct frame_info *this_frame);
 307
 308 /* Same as get_frame_address_in_block, but returns a boolean
 309    indication of whether the frame address is determinable (when the
 310    PC is unavailable, it will not be), instead of possibly throwing an
 311    error trying to read an unavailable PC.  */
 312
 313 extern int
 314   get_frame_address_in_block_if_available (struct frame_info *this_frame,
 315                                            CORE_ADDR *pc);
 316
 317 /* The frame's inner-most bound.  AKA the stack-pointer.  Confusingly
 318    known as top-of-stack.  */
 319
 320 extern CORE_ADDR get_frame_sp (struct frame_info *);
 321
 322 /* Following on from the `resume' address.  Return the entry point
 323    address of the function containing that resume address, or zero if
 324    that function isn't known.  */
 325 extern CORE_ADDR get_frame_func (struct frame_info *fi);
 326
 327 /* Same as get_frame_func, but returns a boolean indication of whether
 328    the frame function is determinable (when the PC is unavailable, it
 329    will not be), instead of possibly throwing an error trying to read
 330    an unavailable PC.  */
 331
 332 extern int get_frame_func_if_available (struct frame_info *fi, CORE_ADDR *);
 333
 334 /* Closely related to the resume address, various symbol table
 335    attributes that are determined by the PC.  Note that for a normal
 336    frame, the PC refers to the resume address after the return, and
 337    not the call instruction.  In such a case, the address is adjusted
 338    so that it (approximately) identifies the call site (and not the
 339    return site).
 340
 341    NOTE: cagney/2002-11-28: The frame cache could be used to cache the
 342    computed value.  Working on the assumption that the bottle-neck is
 343    in the single step code, and that code causes the frame cache to be
 344    constantly flushed, caching things in a frame is probably of little
 345    benefit.  As they say `show us the numbers'.
 346
 347    NOTE: cagney/2002-11-28: Plenty more where this one came from:
 348    find_frame_block(), find_frame_partial_function(),
 349    find_frame_symtab(), find_frame_function().  Each will need to be
 350    carefully considered to determine if the real intent was for it to
 351    apply to the PC or the adjusted PC.  */
 352 extern void find_frame_sal (struct frame_info *frame,
 353                             struct symtab_and_line *sal);
 354
 355 /* Set the current source and line to the location given by frame
 356    FRAME, if possible.  When CENTER is true, adjust so the relevant
 357    line is in the center of the next 'list'.  */
 358
 359 void set_current_sal_from_frame (struct frame_info *, int);
 360
 361 /* Return the frame base (what ever that is) (DEPRECATED).
 362
 363    Old code was trying to use this single method for two conflicting
 364    purposes.  Such code needs to be updated to use either of:
 365
 366    get_frame_id: A low level frame unique identifier, that consists of
 367    both a stack and a function address, that can be used to uniquely
 368    identify a frame.  This value is determined by the frame's
 369    low-level unwinder, the stack part [typically] being the
 370    top-of-stack of the previous frame, and the function part being the
 371    function's start address.  Since the correct identification of a
 372    frameless function requires both a stack and function address,
 373    the old get_frame_base method was not sufficient.
 374
 375    get_frame_base_address: get_frame_locals_address:
 376    get_frame_args_address: A set of high-level debug-info dependant
 377    addresses that fall within the frame.  These addresses almost
 378    certainly will not match the stack address part of a frame ID (as
 379    returned by get_frame_base).
 380
 381    This replaced: frame->frame; */
 382
 383 extern CORE_ADDR get_frame_base (struct frame_info *);
 384
 385 /* Return the per-frame unique identifer.  Can be used to relocate a
 386    frame after a frame cache flush (and other similar operations).  If
 387    FI is NULL, return the null_frame_id.
 388
 389    NOTE: kettenis/20040508: These functions return a structure.  On
 390    platforms where structures are returned in static storage (vax,
 391    m68k), this may trigger compiler bugs in code like:
 392
 393    if (frame_id_eq (get_frame_id (l), get_frame_id (r)))
 394
 395    where the return value from the first get_frame_id (l) gets
 396    overwritten by the second get_frame_id (r).  Please avoid writing
 397    code like this.  Use code like:
 398
 399    struct frame_id id = get_frame_id (l);
 400    if (frame_id_eq (id, get_frame_id (r)))
 401
 402    instead, since that avoids the bug.  */
 403 extern struct frame_id get_frame_id (struct frame_info *fi);
 404 extern struct frame_id get_stack_frame_id (struct frame_info *fi);
 405 extern struct frame_id frame_unwind_caller_id (struct frame_info *next_frame);
 406
 407 /* Assuming that a frame is `normal', return its base-address, or 0 if
 408    the information isn't available.  NOTE: This address is really only
 409    meaningful to the frame's high-level debug info.  */
 410 extern CORE_ADDR get_frame_base_address (struct frame_info *);
 411
 412 /* Assuming that a frame is `normal', return the base-address of the
 413    local variables, or 0 if the information isn't available.  NOTE:
 414    This address is really only meaningful to the frame's high-level
 415    debug info.  Typically, the argument and locals share a single
 416    base-address.  */
 417 extern CORE_ADDR get_frame_locals_address (struct frame_info *);
 418
 419 /* Assuming that a frame is `normal', return the base-address of the
 420    parameter list, or 0 if that information isn't available.  NOTE:
 421    This address is really only meaningful to the frame's high-level
 422    debug info.  Typically, the argument and locals share a single
 423    base-address.  */
 424 extern CORE_ADDR get_frame_args_address (struct frame_info *);
 425
 426 /* The frame's level: 0 for innermost, 1 for its caller, ...; or -1
 427    for an invalid frame).  */
 428 extern int frame_relative_level (struct frame_info *fi);
 429
 430 /* Return the frame's type.  */
 431
 432 extern enum frame_type get_frame_type (struct frame_info *);
 433
 434 /* Return the frame's program space.  */
 435 extern struct program_space *get_frame_program_space (struct frame_info *);
 436
 437 /* Unwind THIS frame's program space from the NEXT frame.  */
 438 extern struct program_space *frame_unwind_program_space (struct frame_info *);
 439
 440 /* Return the frame's address space.  */
 441 extern struct address_space *get_frame_address_space (struct frame_info *);
 442
 443 /* For frames where we can not unwind further, describe why.  */
 444
 445 enum unwind_stop_reason
 446   {
 447     /* No particular reason; either we haven't tried unwinding yet,
 448        or we didn't fail.  */
 449     UNWIND_NO_REASON,
 450
 451     /* The previous frame's analyzer returns an invalid result
 452        from this_id.
 453
 454        FIXME drow/2006-08-16: This is how GDB used to indicate end of
 455        stack.  We should migrate to a model where frames always have a
 456        valid ID, and this becomes not just an error but an internal
 457        error.  But that's a project for another day.  */
 458     UNWIND_NULL_ID,
 459
 460     /* All the conditions after this point are considered errors;
 461        abnormal stack termination.  If a backtrace stops for one
 462        of these reasons, we'll let the user know.  This marker
 463        is not a valid stop reason.  */
 464     UNWIND_FIRST_ERROR,
 465
 466     /* This frame ID looks like it ought to belong to a NEXT frame,
 467        but we got it for a PREV frame.  Normally, this is a sign of
 468        unwinder failure.  It could also indicate stack corruption.  */
 469     UNWIND_INNER_ID,
 470
 471     /* This frame has the same ID as the previous one.  That means
 472        that unwinding further would almost certainly give us another
 473        frame with exactly the same ID, so break the chain.  Normally,
 474        this is a sign of unwinder failure.  It could also indicate
 475        stack corruption.  */
 476     UNWIND_SAME_ID,
 477
 478     /* The frame unwinder didn't find any saved PC, but we needed
 479        one to unwind further.  */
 480     UNWIND_NO_SAVED_PC,
 481   };
 482
 483 /* Return the reason why we can't unwind past this frame.  */
 484
 485 enum unwind_stop_reason get_frame_unwind_stop_reason (struct frame_info *);
 486
 487 /* Translate a reason code to an informative string.  */
 488
 489 const char *frame_stop_reason_string (enum unwind_stop_reason);
 490
 491 /* Unwind the stack frame so that the value of REGNUM, in the previous
 492    (up, older) frame is returned.  If VALUEP is NULL, don't
 493    fetch/compute the value.  Instead just return the location of the
 494    value.  */
 495 extern void frame_register_unwind (struct frame_info *frame, int regnum,
 496                                    int *optimizedp, int *unavailablep,
 497                                    enum lval_type *lvalp,
 498                                    CORE_ADDR *addrp, int *realnump,
 499                                    gdb_byte *valuep);
 500
 501 /* Fetch a register from this, or unwind a register from the next
 502    frame.  Note that the get_frame methods are wrappers to
 503    frame->next->unwind.  They all [potentially] throw an error if the
 504    fetch fails.  The value methods never return NULL, but usually
 505    do return a lazy value.  */
 506
 507 extern void frame_unwind_register (struct frame_info *frame,
 508                                    int regnum, gdb_byte *buf);
 509 extern void get_frame_register (struct frame_info *frame,
 510                                 int regnum, gdb_byte *buf);
 511
 512 struct value *frame_unwind_register_value (struct frame_info *frame,
 513                                            int regnum);
 514 struct value *get_frame_register_value (struct frame_info *frame,
 515                                         int regnum);
 516
 517 extern LONGEST frame_unwind_register_signed (struct frame_info *frame,
 518                                              int regnum);
 519 extern LONGEST get_frame_register_signed (struct frame_info *frame,
 520                                           int regnum);
 521 extern ULONGEST frame_unwind_register_unsigned (struct frame_info *frame,
 522                                                int regnum);
 523 extern ULONGEST get_frame_register_unsigned (struct frame_info *frame,
 524                                              int regnum);
 525
 526
 527 /* Get the value of the register that belongs to this FRAME.  This
 528    function is a wrapper to the call sequence ``frame_register_unwind
 529    (get_next_frame (FRAME))''.  As per frame_register_unwind(), if
 530    VALUEP is NULL, the registers value is not fetched/computed.  */
 531
 532 extern void frame_register (struct frame_info *frame, int regnum,
 533                             int *optimizedp, int *unavailablep,
 534                             enum lval_type *lvalp,
 535                             CORE_ADDR *addrp, int *realnump,
 536                             gdb_byte *valuep);
 537
 538 /* The reverse.  Store a register value relative to the specified
 539    frame.  Note: this call makes the frame's state undefined.  The
 540    register and frame caches must be flushed.  */
 541 extern void put_frame_register (struct frame_info *frame, int regnum,
 542                                 const gdb_byte *buf);
 543
 544 /* Read LEN bytes from one or multiple registers starting with REGNUM
 545    in frame FRAME, starting at OFFSET, into BUF.  If the register
 546    contents are optimized out or unavailable, set *OPTIMIZEDP,
 547    *UNAVAILABLEP accordingly.  */
 548 extern int get_frame_register_bytes (struct frame_info *frame, int regnum,
 549                                      CORE_ADDR offset, int len,
 550                                      gdb_byte *myaddr,
 551                                      int *optimizedp, int *unavailablep);
 552
 553 /* Write LEN bytes to one or multiple registers starting with REGNUM
 554    in frame FRAME, starting at OFFSET, into BUF.  */
 555 extern void put_frame_register_bytes (struct frame_info *frame, int regnum,
 556                                       CORE_ADDR offset, int len,
 557                                       const gdb_byte *myaddr);
 558
 559 /* Unwind the PC.  Strictly speaking return the resume address of the
 560    calling frame.  For GDB, `pc' is the resume address and not a
 561    specific register.  */
 562
 563 extern CORE_ADDR frame_unwind_caller_pc (struct frame_info *frame);
 564
 565 /* Same as frame_unwind_caller_pc, but returns a boolean indication of
 566    whether the caller PC is determinable (when the PC is unavailable,
 567    it will not be), instead of possibly throwing an error trying to
 568    read unavailable memory or registers.  */
 569
 570 extern int frame_unwind_caller_pc_if_available (struct frame_info *this_frame,
 571                                                 CORE_ADDR *pc);
 572
 573 /* Discard the specified frame.  Restoring the registers to the state
 574    of the caller.  */
 575 extern void frame_pop (struct frame_info *frame);
 576
 577 /* Return memory from the specified frame.  A frame knows its thread /
 578    LWP and hence can find its way down to a target.  The assumption
 579    here is that the current and previous frame share a common address
 580    space.
 581
 582    If the memory read fails, these methods throw an error.
 583
 584    NOTE: cagney/2003-06-03: Should there be unwind versions of these
 585    methods?  That isn't clear.  Can code, for instance, assume that
 586    this and the previous frame's memory or architecture are identical?
 587    If architecture / memory changes are always separated by special
 588    adaptor frames this should be ok.  */
 589
 590 extern void get_frame_memory (struct frame_info *this_frame, CORE_ADDR addr,
 591                               gdb_byte *buf, int len);
 592 extern LONGEST get_frame_memory_signed (struct frame_info *this_frame,
 593                                         CORE_ADDR memaddr, int len);
 594 extern ULONGEST get_frame_memory_unsigned (struct frame_info *this_frame,
 595                                            CORE_ADDR memaddr, int len);
 596
 597 /* Same as above, but return non-zero when the entire memory read
 598    succeeds, zero otherwize.  */
 599 extern int safe_frame_unwind_memory (struct frame_info *this_frame,
 600                                      CORE_ADDR addr, gdb_byte *buf, int len);
 601
 602 /* Return this frame's architecture.  */
 603 extern struct gdbarch *get_frame_arch (struct frame_info *this_frame);
 604
 605 /* Return the previous frame's architecture.  */
 606 extern struct gdbarch *frame_unwind_arch (struct frame_info *frame);
 607
 608 /* Return the previous frame's architecture, skipping inline functions.  */
 609 extern struct gdbarch *frame_unwind_caller_arch (struct frame_info *frame);
 610
 611
 612 /* Values for the source flag to be used in print_frame_info_base().  */
 613 enum print_what
 614   {
 615     /* Print only the source line, like in stepi.  */
 616     SRC_LINE = -1,
 617     /* Print only the location, i.e. level, address (sometimes)
 618        function, args, file, line, line num.  */
 619     LOCATION,
 620     /* Print both of the above.  */
 621     SRC_AND_LOC,
 622     /* Print location only, but always include the address.  */
 623     LOC_AND_ADDRESS
 624   };
 625
 626 /* Allocate zero initialized memory from the frame cache obstack.
 627    Appendices to the frame info (such as the unwind cache) should
 628    allocate memory using this method.  */
 629
 630 extern void *frame_obstack_zalloc (unsigned long size);
 631 #define FRAME_OBSTACK_ZALLOC(TYPE) \
 632   ((TYPE *) frame_obstack_zalloc (sizeof (TYPE)))
 633 #define FRAME_OBSTACK_CALLOC(NUMBER,TYPE) \
 634   ((TYPE *) frame_obstack_zalloc ((NUMBER) * sizeof (TYPE)))
 635
 636 /* Create a regcache, and copy the frame's registers into it.  */
 637 struct regcache *frame_save_as_regcache (struct frame_info *this_frame);
 638
 639 extern struct block *get_frame_block (struct frame_info *,
 640                                       CORE_ADDR *addr_in_block);
 641
 642 /* Return the `struct block' that belongs to the selected thread's
 643    selected frame.  If the inferior has no state, return NULL.
 644
 645    NOTE: cagney/2002-11-29:
 646
 647    No state?  Does the inferior have any execution state (a core file
 648    does, an executable does not).  At present the code tests
 649    `target_has_stack' but I'm left wondering if it should test
 650    `target_has_registers' or, even, a merged target_has_state.
 651
 652    Should it look at the most recently specified SAL?  If the target
 653    has no state, should this function try to extract a block from the
 654    most recently selected SAL?  That way `list foo' would give it some
 655    sort of reference point.  Then again, perhaps that would confuse
 656    things.
 657
 658    Calls to this function can be broken down into two categories: Code
 659    that uses the selected block as an additional, but optional, data
 660    point; Code that uses the selected block as a prop, when it should
 661    have the relevant frame/block/pc explicitly passed in.
 662
 663    The latter can be eliminated by correctly parameterizing the code,
 664    the former though is more interesting.  Per the "address" command,
 665    it occurs in the CLI code and makes it possible for commands to
 666    work, even when the inferior has no state.  */
 667
 668 extern struct block *get_selected_block (CORE_ADDR *addr_in_block);
 669
 670 extern struct symbol *get_frame_function (struct frame_info *);
 671
 672 extern CORE_ADDR get_pc_function_start (CORE_ADDR);
 673
 674 extern struct frame_info *find_relative_frame (struct frame_info *, int *);
 675
 676 extern void show_and_print_stack_frame (struct frame_info *fi, int print_level,
 677                                         enum print_what print_what);
 678
 679 extern void print_stack_frame (struct frame_info *, int print_level,
 680                                enum print_what print_what);
 681
 682 extern void print_frame_info (struct frame_info *, int print_level,
 683                               enum print_what print_what, int args);
 684
 685 extern struct frame_info *block_innermost_frame (struct block *);
 686
 687 extern int deprecated_pc_in_call_dummy (struct gdbarch *gdbarch, CORE_ADDR pc);
 688
 689 /* FIXME: cagney/2003-02-02: Should be deprecated or replaced with a
 690    function called get_frame_register_p().  This slightly weird (and
 691    older) variant of get_frame_register() returns zero (indicating the
 692    register value is unavailable/invalid) if either: the register
 693    isn't cached; or the register has been optimized out; or the
 694    register contents are unavailable (because they haven't been
 695    collected in a traceframe).  Problem is, neither check is exactly
 696    correct.  A register can't be optimized out (it may not have been
 697    saved as part of a function call); The fact that a register isn't
 698    in the register cache doesn't mean that the register isn't
 699    available (it could have been fetched from memory).  */
 700
 701 extern int frame_register_read (struct frame_info *frame, int regnum,
 702                                 gdb_byte *buf);
 703
 704 /* From stack.c.  */
 705 extern void args_info (char *, int);
 706
 707 extern void locals_info (char *, int);
 708
 709 extern void (*deprecated_selected_frame_level_changed_hook) (int);
 710
 711 extern void return_command (char *, int);
 712
 713 /* Set FRAME's unwinder temporarily, so that we can call a sniffer.
 714    Return a cleanup which should be called if unwinding fails, and
 715    discarded if it succeeds.  */
 716
 717 struct cleanup *frame_prepare_for_sniffer (struct frame_info *frame,
 718                                            const struct frame_unwind *unwind);
 719
 720 /* Notes (cagney/2002-11-27, drow/2003-09-06):
 721
 722    You might think that calls to this function can simply be replaced by a
 723    call to get_selected_frame().
 724
 725    Unfortunately, it isn't that easy.
 726
 727    The relevant code needs to be audited to determine if it is
 728    possible (or practical) to instead pass the applicable frame in as a
 729    parameter.  For instance, DEPRECATED_DO_REGISTERS_INFO() relied on
 730    the deprecated_selected_frame global, while its replacement,
 731    PRINT_REGISTERS_INFO(), is parameterized with the selected frame.
 732    The only real exceptions occur at the edge (in the CLI code) where
 733    user commands need to pick up the selected frame before proceeding.
 734
 735    There are also some functions called with a NULL frame meaning either "the
 736    program is not running" or "use the selected frame".
 737
 738    This is important.  GDB is trying to stamp out the hack:
 739
 740    saved_frame = deprecated_safe_get_selected_frame ();
 741    select_frame (...);
 742    hack_using_global_selected_frame ();
 743    select_frame (saved_frame);
 744
 745    Take care!
 746
 747    This function calls get_selected_frame if the inferior should have a
 748    frame, or returns NULL otherwise.  */
 749
 750 extern struct frame_info *deprecated_safe_get_selected_frame (void);
 751
 752 /* Create a frame using the specified BASE and PC.  */
 753
 754 extern struct frame_info *create_new_frame (CORE_ADDR base, CORE_ADDR pc);
 755
 756 /* Return true if the frame unwinder for frame FI is UNWINDER; false
 757    otherwise.  */
 758
 759 extern int frame_unwinder_is (struct frame_info *fi,
 760                               const struct frame_unwind *unwinder);
 761
 762 #endif /* !defined (FRAME_H)  */