gdb/frame.h

   1 /* Definitions for dealing with stack frames, for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2021 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #if !defined (FRAME_H)
  21 #define FRAME_H 1
  22
  23 /* The following is the intended naming schema for frame functions.
  24    It isn't 100% consistent, but it is approaching that.  Frame naming
  25    schema:
  26
  27    Prefixes:
  28
  29    get_frame_WHAT...(): Get WHAT from the THIS frame (functionally
  30    equivalent to THIS->next->unwind->what)
  31
  32    frame_unwind_WHAT...(): Unwind THIS frame's WHAT from the NEXT
  33    frame.
  34
  35    frame_unwind_caller_WHAT...(): Unwind WHAT for NEXT stack frame's
  36    real caller.  Any inlined functions in NEXT's stack frame are
  37    skipped.  Use these to ignore any potentially inlined functions,
  38    e.g. inlined into the first instruction of a library trampoline.
  39
  40    get_stack_frame_WHAT...(): Get WHAT for THIS frame, but if THIS is
  41    inlined, skip to the containing stack frame.
  42
  43    put_frame_WHAT...(): Put a value into this frame (unsafe, need to
  44    invalidate the frame / regcache afterwards) (better name more
  45    strongly hinting at its unsafeness)
  46
  47    safe_....(): Safer version of various functions, doesn't throw an
  48    error (leave this for later?).  Returns true / non-NULL if the request
  49    succeeds, false / NULL otherwise.
  50
  51    Suffixes:
  52
  53    void /frame/_WHAT(): Read WHAT's value into the buffer parameter.
  54
  55    ULONGEST /frame/_WHAT_unsigned(): Return an unsigned value (the
  56    alternative is *frame_unsigned_WHAT).
  57
  58    LONGEST /frame/_WHAT_signed(): Return WHAT signed value.
  59
  60    What:
  61
  62    /frame/_memory* (frame, coreaddr, len [, buf]): Extract/return
  63    *memory.
  64
  65    /frame/_register* (frame, regnum [, buf]): extract/return register.
  66
  67    CORE_ADDR /frame/_{pc,sp,...} (frame): Resume address, innner most
  68    stack *address, ...
  69
  70    */
  71
  72 #include "language.h"
  73 #include "cli/cli-option.h"
  74 #include "gdbsupport/common-debug.h"
  75
  76 struct symtab_and_line;
  77 struct frame_unwind;
  78 struct frame_base;
  79 struct block;
  80 struct gdbarch;
  81 struct ui_file;
  82 struct ui_out;
  83 struct frame_print_options;
  84
  85 /* Status of a given frame's stack.  */
  86
  87 enum frame_id_stack_status
  88 {
  89   /* Stack address is invalid.  */
  90   FID_STACK_INVALID = 0,
  91
  92   /* Stack address is valid, and is found in the stack_addr field.  */
  93   FID_STACK_VALID = 1,
  94
  95   /* Sentinel frame.  */
  96   FID_STACK_SENTINEL = 2,
  97
  98   /* Outer frame.  Since a frame's stack address is typically defined as the
  99      value the stack pointer had prior to the activation of the frame, an outer
 100      frame doesn't have a stack address.  The frame ids of frames inlined in the
 101      outer frame are also of this type.  */
 102   FID_STACK_OUTER = 3,
 103
 104   /* Stack address is unavailable.  I.e., there's a valid stack, but
 105      we don't know where it is (because memory or registers we'd
 106      compute it from were not collected).  */
 107   FID_STACK_UNAVAILABLE = -1
 108 };
 109
 110 /* The frame object.  */
 111
 112 struct frame_info;
 113
 114 /* The frame object's ID.  This provides a per-frame unique identifier
 115    that can be used to relocate a `struct frame_info' after a target
 116    resume or a frame cache destruct.  It of course assumes that the
 117    inferior hasn't unwound the stack past that frame.  */
 118
 119 struct frame_id
 120 {
 121   /* The frame's stack address.  This shall be constant through out
 122      the lifetime of a frame.  Note that this requirement applies to
 123      not just the function body, but also the prologue and (in theory
 124      at least) the epilogue.  Since that value needs to fall either on
 125      the boundary, or within the frame's address range, the frame's
 126      outer-most address (the inner-most address of the previous frame)
 127      is used.  Watch out for all the legacy targets that still use the
 128      function pointer register or stack pointer register.  They are
 129      wrong.
 130
 131      This field is valid only if frame_id.stack_status is
 132      FID_STACK_VALID.  It will be 0 for other
 133      FID_STACK_... statuses.  */
 134   CORE_ADDR stack_addr;
 135
 136   /* The frame's code address.  This shall be constant through out the
 137      lifetime of the frame.  While the PC (a.k.a. resume address)
 138      changes as the function is executed, this code address cannot.
 139      Typically, it is set to the address of the entry point of the
 140      frame's function (as returned by get_frame_func).
 141
 142      For inlined functions (INLINE_DEPTH != 0), this is the address of
 143      the first executed instruction in the block corresponding to the
 144      inlined function.
 145
 146      This field is valid only if code_addr_p is true.  Otherwise, this
 147      frame is considered to have a wildcard code address, i.e. one that
 148      matches every address value in frame comparisons.  */
 149   CORE_ADDR code_addr;
 150
 151   /* The frame's special address.  This shall be constant through out the
 152      lifetime of the frame.  This is used for architectures that may have
 153      frames that do not change the stack but are still distinct and have
 154      some form of distinct identifier (e.g. the ia64 which uses a 2nd
 155      stack for registers).  This field is treated as unordered - i.e. will
 156      not be used in frame ordering comparisons.
 157
 158      This field is valid only if special_addr_p is true.  Otherwise, this
 159      frame is considered to have a wildcard special address, i.e. one that
 160      matches every address value in frame comparisons.  */
 161   CORE_ADDR special_addr;
 162
 163   /* Flags to indicate the above fields have valid contents.  */
 164   ENUM_BITFIELD(frame_id_stack_status) stack_status : 3;
 165   unsigned int code_addr_p : 1;
 166   unsigned int special_addr_p : 1;
 167
 168   /* It is non-zero for a frame made up by GDB without stack data
 169      representation in inferior, such as INLINE_FRAME or TAILCALL_FRAME.
 170      Caller of inlined function will have it zero, each more inner called frame
 171      will have it increasingly one, two etc.  Similarly for TAILCALL_FRAME.  */
 172   int artificial_depth;
 173
 174   /* Return a string representation of this frame id.  */
 175   std::string to_string () const;
 176 };
 177
 178 /* Save and restore the currently selected frame.  */
 179
 180 class scoped_restore_selected_frame
 181 {
 182 public:
 183   /* Save the currently selected frame.  */
 184   scoped_restore_selected_frame ();
 185
 186   /* Restore the currently selected frame.  */
 187   ~scoped_restore_selected_frame ();
 188
 189   DISABLE_COPY_AND_ASSIGN (scoped_restore_selected_frame);
 190
 191 private:
 192
 193   /* The ID and level of the previously selected frame.  */
 194   struct frame_id m_fid;
 195   int m_level;
 196
 197   /* Save/restore the language as well, because selecting a frame
 198      changes the current language to the frame's language if "set
 199      language auto".  */
 200   enum language m_lang;
 201 };
 202
 203 /* Methods for constructing and comparing Frame IDs.  */
 204
 205 /* For convenience.  All fields are zero.  This means "there is no frame".  */
 206 extern const struct frame_id null_frame_id;
 207
 208 /* Sentinel frame.  */
 209 extern const struct frame_id sentinel_frame_id;
 210
 211 /* This means "there is no frame ID, but there is a frame".  It should be
 212    replaced by best-effort frame IDs for the outermost frame, somehow.
 213    The implementation is only special_addr_p set.  */
 214 extern const struct frame_id outer_frame_id;
 215
 216 /* Flag to control debugging.  */
 217
 218 extern bool frame_debug;
 219
 220 /* Print a "frame" debug statement.  */
 221
 222 #define frame_debug_printf(fmt, ...) \
 223   debug_prefixed_printf_cond (frame_debug, "frame", fmt, ##__VA_ARGS__)
 224
 225 /* Print "frame" enter/exit debug statements.  */
 226
 227 #define FRAME_SCOPED_DEBUG_ENTER_EXIT \
 228   scoped_debug_enter_exit (frame_debug, "frame")
 229
 230 /* Construct a frame ID.  The first parameter is the frame's constant
 231    stack address (typically the outer-bound), and the second the
 232    frame's constant code address (typically the entry point).
 233    The special identifier address is set to indicate a wild card.  */
 234 extern struct frame_id frame_id_build (CORE_ADDR stack_addr,
 235                                        CORE_ADDR code_addr);
 236
 237 /* Construct a special frame ID.  The first parameter is the frame's constant
 238    stack address (typically the outer-bound), the second is the
 239    frame's constant code address (typically the entry point),
 240    and the third parameter is the frame's special identifier address.  */
 241 extern struct frame_id frame_id_build_special (CORE_ADDR stack_addr,
 242                                                CORE_ADDR code_addr,
 243                                                CORE_ADDR special_addr);
 244
 245 /* Construct a frame ID representing a frame where the stack address
 246    exists, but is unavailable.  CODE_ADDR is the frame's constant code
 247    address (typically the entry point).  The special identifier
 248    address is set to indicate a wild card.  */
 249 extern struct frame_id frame_id_build_unavailable_stack (CORE_ADDR code_addr);
 250
 251 /* Construct a frame ID representing a frame where the stack address
 252    exists, but is unavailable.  CODE_ADDR is the frame's constant code
 253    address (typically the entry point).  SPECIAL_ADDR is the special
 254    identifier address.  */
 255 extern struct frame_id
 256   frame_id_build_unavailable_stack_special (CORE_ADDR code_addr,
 257                                             CORE_ADDR special_addr);
 258
 259 /* Construct a wild card frame ID.  The parameter is the frame's constant
 260    stack address (typically the outer-bound).  The code address as well
 261    as the special identifier address are set to indicate wild cards.  */
 262 extern struct frame_id frame_id_build_wild (CORE_ADDR stack_addr);
 263
 264 /* Returns true when L is a valid frame.  */
 265 extern bool frame_id_p (frame_id l);
 266
 267 /* Returns true when L is a valid frame representing a frame made up by GDB
 268    without stack data representation in inferior, such as INLINE_FRAME or
 269    TAILCALL_FRAME.  */
 270 extern bool frame_id_artificial_p (frame_id l);
 271
 272 /* Returns true when L and R identify the same frame.  */
 273 extern bool frame_id_eq (frame_id l, frame_id r);
 274
 275 /* Frame types.  Some are real, some are signal trampolines, and some
 276    are completely artificial (dummy).  */
 277
 278 enum frame_type
 279 {
 280   /* A true stack frame, created by the target program during normal
 281      execution.  */
 282   NORMAL_FRAME,
 283   /* A fake frame, created by GDB when performing an inferior function
 284      call.  */
 285   DUMMY_FRAME,
 286   /* A frame representing an inlined function, associated with an
 287      upcoming (prev, outer, older) NORMAL_FRAME.  */
 288   INLINE_FRAME,
 289   /* A virtual frame of a tail call - see dwarf2_tailcall_frame_unwind.  */
 290   TAILCALL_FRAME,
 291   /* In a signal handler, various OSs handle this in various ways.
 292      The main thing is that the frame may be far from normal.  */
 293   SIGTRAMP_FRAME,
 294   /* Fake frame representing a cross-architecture call.  */
 295   ARCH_FRAME,
 296   /* Sentinel or registers frame.  This frame obtains register values
 297      direct from the inferior's registers.  */
 298   SENTINEL_FRAME
 299 };
 300
 301 /* For every stopped thread, GDB tracks two frames: current and
 302    selected.  Current frame is the inner most frame of the selected
 303    thread.  Selected frame is the one being examined by the GDB
 304    CLI (selected using `up', `down', ...).  The frames are created
 305    on-demand (via get_prev_frame()) and then held in a frame cache.  */
 306 /* FIXME: cagney/2002-11-28: Er, there is a lie here.  If you do the
 307    sequence: `thread 1; up; thread 2; thread 1' you lose thread 1's
 308    selected frame.  At present GDB only tracks the selected frame of
 309    the current thread.  But be warned, that might change.  */
 310 /* FIXME: cagney/2002-11-14: At any time, only one thread's selected
 311    and current frame can be active.  Switching threads causes gdb to
 312    discard all that cached frame information.  Ulgh!  Instead, current
 313    and selected frame should be bound to a thread.  */
 314
 315 /* On demand, create the inner most frame using information found in
 316    the inferior.  If the inner most frame can't be created, throw an
 317    error.  */
 318 extern struct frame_info *get_current_frame (void);
 319
 320 /* Does the current target interface have enough state to be able to
 321    query the current inferior for frame info, and is the inferior in a
 322    state where that is possible?  */
 323 extern bool has_stack_frames ();
 324
 325 /* Invalidates the frame cache (this function should have been called
 326    invalidate_cached_frames).
 327
 328    FIXME: cagney/2002-11-28: There should be two methods: one that
 329    reverts the thread's selected frame back to current frame (for when
 330    the inferior resumes) and one that does not (for when the user
 331    modifies the target invalidating the frame cache).  */
 332 extern void reinit_frame_cache (void);
 333
 334 /* Return the selected frame.  Always returns non-NULL.  If there
 335    isn't an inferior sufficient for creating a frame, an error is
 336    thrown.  When MESSAGE is non-NULL, use it for the error message,
 337    otherwise use a generic error message.  */
 338 /* FIXME: cagney/2002-11-28: At present, when there is no selected
 339    frame, this function always returns the current (inner most) frame.
 340    It should instead, when a thread has previously had its frame
 341    selected (but not resumed) and the frame cache invalidated, find
 342    and then return that thread's previously selected frame.  */
 343 extern struct frame_info *get_selected_frame (const char *message = nullptr);
 344
 345 /* Select a specific frame.  NULL implies re-select the inner most
 346    frame.  */
 347 extern void select_frame (struct frame_info *);
 348
 349 /* Save the frame ID and frame level of the selected frame in FRAME_ID
 350    and FRAME_LEVEL, to be restored later with restore_selected_frame.
 351
 352    This is preferred over getting the same info out of
 353    get_selected_frame directly because this function does not create
 354    the selected-frame's frame_info object if it hasn't been created
 355    yet, and thus is more efficient and doesn't throw.  */
 356 extern void save_selected_frame (frame_id *frame_id, int *frame_level)
 357   noexcept;
 358
 359 /* Restore selected frame as saved with save_selected_frame.
 360
 361    Does not try to find the corresponding frame_info object.  Instead
 362    the next call to get_selected_frame will look it up and cache the
 363    result.
 364
 365    This function does not throw.  It is designed to be safe to called
 366    from the destructors of RAII types.  */
 367 extern void restore_selected_frame (frame_id frame_id, int frame_level)
 368   noexcept;
 369
 370 /* Lookup the frame_info object for the selected frame FRAME_ID /
 371    FRAME_LEVEL and cache the result.
 372
 373    If FRAME_LEVEL > 0 and the originally selected frame isn't found,
 374    warn and select the innermost (current) frame.  */
 375 extern void lookup_selected_frame (frame_id frame_id, int frame_level);
 376
 377 /* Given a FRAME, return the next (more inner, younger) or previous
 378    (more outer, older) frame.  */
 379 extern struct frame_info *get_prev_frame (struct frame_info *);
 380 extern struct frame_info *get_next_frame (struct frame_info *);
 381
 382 /* Like get_next_frame(), but allows return of the sentinel frame.  NULL
 383    is never returned.  */
 384 extern struct frame_info *get_next_frame_sentinel_okay (struct frame_info *);
 385
 386 /* Return a "struct frame_info" corresponding to the frame that called
 387    THIS_FRAME.  Returns NULL if there is no such frame.
 388
 389    Unlike get_prev_frame, this function always tries to unwind the
 390    frame.  */
 391 extern struct frame_info *get_prev_frame_always (struct frame_info *);
 392
 393 /* Given a frame's ID, relocate the frame.  Returns NULL if the frame
 394    is not found.  */
 395 extern struct frame_info *frame_find_by_id (struct frame_id id);
 396
 397 /* Given a frame's ID, find the previous frame's ID.  Returns null_frame_id
 398    if the frame is not found.  */
 399 extern struct frame_id get_prev_frame_id_by_id (struct frame_id id);
 400
 401 /* Base attributes of a frame: */
 402
 403 /* The frame's `resume' address.  Where the program will resume in
 404    this frame.
 405
 406    This replaced: frame->pc; */
 407 extern CORE_ADDR get_frame_pc (struct frame_info *);
 408
 409 /* Same as get_frame_pc, but return a boolean indication of whether
 410    the PC is actually available, instead of throwing an error.  */
 411
 412 extern bool get_frame_pc_if_available (frame_info *frame, CORE_ADDR *pc);
 413
 414 /* An address (not necessarily aligned to an instruction boundary)
 415    that falls within THIS frame's code block.
 416
 417    When a function call is the last statement in a block, the return
 418    address for the call may land at the start of the next block.
 419    Similarly, if a no-return function call is the last statement in
 420    the function, the return address may end up pointing beyond the
 421    function, and possibly at the start of the next function.
 422
 423    These methods make an allowance for this.  For call frames, this
 424    function returns the frame's PC-1 which "should" be an address in
 425    the frame's block.  */
 426
 427 extern CORE_ADDR get_frame_address_in_block (struct frame_info *this_frame);
 428
 429 /* Same as get_frame_address_in_block, but returns a boolean
 430    indication of whether the frame address is determinable (when the
 431    PC is unavailable, it will not be), instead of possibly throwing an
 432    error trying to read an unavailable PC.  */
 433
 434 extern bool get_frame_address_in_block_if_available (frame_info *this_frame,
 435                                                      CORE_ADDR *pc);
 436
 437 /* The frame's inner-most bound.  AKA the stack-pointer.  Confusingly
 438    known as top-of-stack.  */
 439
 440 extern CORE_ADDR get_frame_sp (struct frame_info *);
 441
 442 /* Following on from the `resume' address.  Return the entry point
 443    address of the function containing that resume address, or zero if
 444    that function isn't known.  */
 445 extern CORE_ADDR get_frame_func (struct frame_info *fi);
 446
 447 /* Same as get_frame_func, but returns a boolean indication of whether
 448    the frame function is determinable (when the PC is unavailable, it
 449    will not be), instead of possibly throwing an error trying to read
 450    an unavailable PC.  */
 451
 452 extern bool get_frame_func_if_available (frame_info *fi, CORE_ADDR *);
 453
 454 /* Closely related to the resume address, various symbol table
 455    attributes that are determined by the PC.  Note that for a normal
 456    frame, the PC refers to the resume address after the return, and
 457    not the call instruction.  In such a case, the address is adjusted
 458    so that it (approximately) identifies the call site (and not the
 459    return site).
 460
 461    NOTE: cagney/2002-11-28: The frame cache could be used to cache the
 462    computed value.  Working on the assumption that the bottle-neck is
 463    in the single step code, and that code causes the frame cache to be
 464    constantly flushed, caching things in a frame is probably of little
 465    benefit.  As they say `show us the numbers'.
 466
 467    NOTE: cagney/2002-11-28: Plenty more where this one came from:
 468    find_frame_block(), find_frame_partial_function(),
 469    find_frame_symtab(), find_frame_function().  Each will need to be
 470    carefully considered to determine if the real intent was for it to
 471    apply to the PC or the adjusted PC.  */
 472 extern symtab_and_line find_frame_sal (frame_info *frame);
 473
 474 /* Set the current source and line to the location given by frame
 475    FRAME, if possible.  */
 476
 477 void set_current_sal_from_frame (struct frame_info *);
 478
 479 /* Return the frame base (what ever that is) (DEPRECATED).
 480
 481    Old code was trying to use this single method for two conflicting
 482    purposes.  Such code needs to be updated to use either of:
 483
 484    get_frame_id: A low level frame unique identifier, that consists of
 485    both a stack and a function address, that can be used to uniquely
 486    identify a frame.  This value is determined by the frame's
 487    low-level unwinder, the stack part [typically] being the
 488    top-of-stack of the previous frame, and the function part being the
 489    function's start address.  Since the correct identification of a
 490    frameless function requires both a stack and function address,
 491    the old get_frame_base method was not sufficient.
 492
 493    get_frame_base_address: get_frame_locals_address:
 494    get_frame_args_address: A set of high-level debug-info dependant
 495    addresses that fall within the frame.  These addresses almost
 496    certainly will not match the stack address part of a frame ID (as
 497    returned by get_frame_base).
 498
 499    This replaced: frame->frame; */
 500
 501 extern CORE_ADDR get_frame_base (struct frame_info *);
 502
 503 /* Return the per-frame unique identifer.  Can be used to relocate a
 504    frame after a frame cache flush (and other similar operations).  If
 505    FI is NULL, return the null_frame_id.
 506
 507    NOTE: kettenis/20040508: These functions return a structure.  On
 508    platforms where structures are returned in static storage (vax,
 509    m68k), this may trigger compiler bugs in code like:
 510
 511    if (frame_id_eq (get_frame_id (l), get_frame_id (r)))
 512
 513    where the return value from the first get_frame_id (l) gets
 514    overwritten by the second get_frame_id (r).  Please avoid writing
 515    code like this.  Use code like:
 516
 517    struct frame_id id = get_frame_id (l);
 518    if (frame_id_eq (id, get_frame_id (r)))
 519
 520    instead, since that avoids the bug.  */
 521 extern struct frame_id get_frame_id (struct frame_info *fi);
 522 extern struct frame_id get_stack_frame_id (struct frame_info *fi);
 523 extern struct frame_id frame_unwind_caller_id (struct frame_info *next_frame);
 524
 525 /* Assuming that a frame is `normal', return its base-address, or 0 if
 526    the information isn't available.  NOTE: This address is really only
 527    meaningful to the frame's high-level debug info.  */
 528 extern CORE_ADDR get_frame_base_address (struct frame_info *);
 529
 530 /* Assuming that a frame is `normal', return the base-address of the
 531    local variables, or 0 if the information isn't available.  NOTE:
 532    This address is really only meaningful to the frame's high-level
 533    debug info.  Typically, the argument and locals share a single
 534    base-address.  */
 535 extern CORE_ADDR get_frame_locals_address (struct frame_info *);
 536
 537 /* Assuming that a frame is `normal', return the base-address of the
 538    parameter list, or 0 if that information isn't available.  NOTE:
 539    This address is really only meaningful to the frame's high-level
 540    debug info.  Typically, the argument and locals share a single
 541    base-address.  */
 542 extern CORE_ADDR get_frame_args_address (struct frame_info *);
 543
 544 /* The frame's level: 0 for innermost, 1 for its caller, ...; or -1
 545    for an invalid frame).  */
 546 extern int frame_relative_level (struct frame_info *fi);
 547
 548 /* Return the frame's type.  */
 549
 550 extern enum frame_type get_frame_type (struct frame_info *);
 551
 552 /* Return the frame's program space.  */
 553 extern struct program_space *get_frame_program_space (struct frame_info *);
 554
 555 /* Unwind THIS frame's program space from the NEXT frame.  */
 556 extern struct program_space *frame_unwind_program_space (struct frame_info *);
 557
 558 class address_space;
 559
 560 /* Return the frame's address space.  */
 561 extern const address_space *get_frame_address_space (struct frame_info *);
 562
 563 /* For frames where we can not unwind further, describe why.  */
 564
 565 enum unwind_stop_reason
 566   {
 567 #define SET(name, description) name,
 568 #define FIRST_ENTRY(name) UNWIND_FIRST = name,
 569 #define LAST_ENTRY(name) UNWIND_LAST = name,
 570 #define FIRST_ERROR(name) UNWIND_FIRST_ERROR = name,
 571
 572 #include "unwind_stop_reasons.def"
 573 #undef SET
 574 #undef FIRST_ENTRY
 575 #undef LAST_ENTRY
 576 #undef FIRST_ERROR
 577   };
 578
 579 /* Return the reason why we can't unwind past this frame.  */
 580
 581 enum unwind_stop_reason get_frame_unwind_stop_reason (struct frame_info *);
 582
 583 /* Translate a reason code to an informative string.  This converts the
 584    generic stop reason codes into a generic string describing the code.
 585    For a possibly frame specific string explaining the stop reason, use
 586    FRAME_STOP_REASON_STRING instead.  */
 587
 588 const char *unwind_stop_reason_to_string (enum unwind_stop_reason);
 589
 590 /* Return a possibly frame specific string explaining why the unwind
 591    stopped here.  E.g., if unwinding tripped on a memory error, this
 592    will return the error description string, which includes the address
 593    that we failed to access.  If there's no specific reason stored for
 594    a frame then a generic reason string will be returned.
 595
 596    Should only be called for frames that don't have a previous frame.  */
 597
 598 const char *frame_stop_reason_string (struct frame_info *);
 599
 600 /* Unwind the stack frame so that the value of REGNUM, in the previous
 601    (up, older) frame is returned.  If VALUEP is NULL, don't
 602    fetch/compute the value.  Instead just return the location of the
 603    value.  */
 604 extern void frame_register_unwind (frame_info *frame, int regnum,
 605                                    int *optimizedp, int *unavailablep,
 606                                    enum lval_type *lvalp,
 607                                    CORE_ADDR *addrp, int *realnump,
 608                                    gdb_byte *valuep);
 609
 610 /* Fetch a register from this, or unwind a register from the next
 611    frame.  Note that the get_frame methods are wrappers to
 612    frame->next->unwind.  They all [potentially] throw an error if the
 613    fetch fails.  The value methods never return NULL, but usually
 614    do return a lazy value.  */
 615
 616 extern void frame_unwind_register (frame_info *next_frame,
 617                                    int regnum, gdb_byte *buf);
 618 extern void get_frame_register (struct frame_info *frame,
 619                                 int regnum, gdb_byte *buf);
 620
 621 struct value *frame_unwind_register_value (frame_info *next_frame,
 622                                            int regnum);
 623 struct value *get_frame_register_value (struct frame_info *frame,
 624                                         int regnum);
 625
 626 extern LONGEST frame_unwind_register_signed (frame_info *next_frame,
 627                                              int regnum);
 628 extern LONGEST get_frame_register_signed (struct frame_info *frame,
 629                                           int regnum);
 630 extern ULONGEST frame_unwind_register_unsigned (frame_info *frame,
 631                                                 int regnum);
 632 extern ULONGEST get_frame_register_unsigned (struct frame_info *frame,
 633                                              int regnum);
 634
 635 /* Read a register from this, or unwind a register from the next
 636    frame.  Note that the read_frame methods are wrappers to
 637    get_frame_register_value, that do not throw if the result is
 638    optimized out or unavailable.  */
 639
 640 extern bool read_frame_register_unsigned (frame_info *frame,
 641                                           int regnum, ULONGEST *val);
 642
 643 /* Get the value of the register that belongs to this FRAME.  This
 644    function is a wrapper to the call sequence ``frame_register_unwind
 645    (get_next_frame (FRAME))''.  As per frame_register_unwind(), if
 646    VALUEP is NULL, the registers value is not fetched/computed.  */
 647
 648 extern void frame_register (struct frame_info *frame, int regnum,
 649                             int *optimizedp, int *unavailablep,
 650                             enum lval_type *lvalp,
 651                             CORE_ADDR *addrp, int *realnump,
 652                             gdb_byte *valuep);
 653
 654 /* The reverse.  Store a register value relative to the specified
 655    frame.  Note: this call makes the frame's state undefined.  The
 656    register and frame caches must be flushed.  */
 657 extern void put_frame_register (struct frame_info *frame, int regnum,
 658                                 const gdb_byte *buf);
 659
 660 /* Read LEN bytes from one or multiple registers starting with REGNUM
 661    in frame FRAME, starting at OFFSET, into BUF.  If the register
 662    contents are optimized out or unavailable, set *OPTIMIZEDP,
 663    *UNAVAILABLEP accordingly.  */
 664 extern bool get_frame_register_bytes (frame_info *frame, int regnum,
 665                                       CORE_ADDR offset,
 666                                       gdb::array_view<gdb_byte> buffer,
 667                                       int *optimizedp, int *unavailablep);
 668
 669 /* Write bytes from BUFFER to one or multiple registers starting with REGNUM
 670    in frame FRAME, starting at OFFSET.  */
 671 extern void put_frame_register_bytes (struct frame_info *frame, int regnum,
 672                                       CORE_ADDR offset,
 673                                       gdb::array_view<const gdb_byte> buffer);
 674
 675 /* Unwind the PC.  Strictly speaking return the resume address of the
 676    calling frame.  For GDB, `pc' is the resume address and not a
 677    specific register.  */
 678
 679 extern CORE_ADDR frame_unwind_caller_pc (struct frame_info *frame);
 680
 681 /* Discard the specified frame.  Restoring the registers to the state
 682    of the caller.  */
 683 extern void frame_pop (struct frame_info *frame);
 684
 685 /* Return memory from the specified frame.  A frame knows its thread /
 686    LWP and hence can find its way down to a target.  The assumption
 687    here is that the current and previous frame share a common address
 688    space.
 689
 690    If the memory read fails, these methods throw an error.
 691
 692    NOTE: cagney/2003-06-03: Should there be unwind versions of these
 693    methods?  That isn't clear.  Can code, for instance, assume that
 694    this and the previous frame's memory or architecture are identical?
 695    If architecture / memory changes are always separated by special
 696    adaptor frames this should be ok.  */
 697
 698 extern void get_frame_memory (struct frame_info *this_frame, CORE_ADDR addr,
 699                               gdb::array_view<gdb_byte> buffer);
 700 extern LONGEST get_frame_memory_signed (struct frame_info *this_frame,
 701                                         CORE_ADDR memaddr, int len);
 702 extern ULONGEST get_frame_memory_unsigned (struct frame_info *this_frame,
 703                                            CORE_ADDR memaddr, int len);
 704
 705 /* Same as above, but return true zero when the entire memory read
 706    succeeds, false otherwise.  */
 707 extern bool safe_frame_unwind_memory (frame_info *this_frame, CORE_ADDR addr,
 708                                       gdb::array_view<gdb_byte> buffer);
 709
 710 /* Return this frame's architecture.  */
 711 extern struct gdbarch *get_frame_arch (struct frame_info *this_frame);
 712
 713 /* Return the previous frame's architecture.  */
 714 extern struct gdbarch *frame_unwind_arch (frame_info *next_frame);
 715
 716 /* Return the previous frame's architecture, skipping inline functions.  */
 717 extern struct gdbarch *frame_unwind_caller_arch (struct frame_info *frame);
 718
 719
 720 /* Values for the source flag to be used in print_frame_info ().
 721    For all the cases below, the address is never printed if
 722    'set print address' is off.  When 'set print address' is on,
 723    the address is printed if the program counter is not at the
 724    beginning of the source line of the frame
 725    and PRINT_WHAT is != LOC_AND_ADDRESS.  */
 726 enum print_what
 727   {
 728     /* Print only the address, source line, like in stepi.  */
 729     SRC_LINE = -1,
 730     /* Print only the location, i.e. level, address,
 731        function, args (as controlled by 'set print frame-arguments'),
 732        file, line, line num.  */
 733     LOCATION,
 734     /* Print both of the above.  */
 735     SRC_AND_LOC,
 736     /* Print location only, print the address even if the program counter
 737        is at the beginning of the source line.  */
 738     LOC_AND_ADDRESS,
 739     /* Print only level and function,
 740        i.e. location only, without address, file, line, line num.  */
 741     SHORT_LOCATION
 742   };
 743
 744 /* Allocate zero initialized memory from the frame cache obstack.
 745    Appendices to the frame info (such as the unwind cache) should
 746    allocate memory using this method.  */
 747
 748 extern void *frame_obstack_zalloc (unsigned long size);
 749 #define FRAME_OBSTACK_ZALLOC(TYPE) \
 750   ((TYPE *) frame_obstack_zalloc (sizeof (TYPE)))
 751 #define FRAME_OBSTACK_CALLOC(NUMBER,TYPE) \
 752   ((TYPE *) frame_obstack_zalloc ((NUMBER) * sizeof (TYPE)))
 753
 754 class readonly_detached_regcache;
 755 /* Create a regcache, and copy the frame's registers into it.  */
 756 std::unique_ptr<readonly_detached_regcache> frame_save_as_regcache
 757     (struct frame_info *this_frame);
 758
 759 extern const struct block *get_frame_block (struct frame_info *,
 760                                             CORE_ADDR *addr_in_block);
 761
 762 /* Return the `struct block' that belongs to the selected thread's
 763    selected frame.  If the inferior has no state, return NULL.
 764
 765    NOTE: cagney/2002-11-29:
 766
 767    No state?  Does the inferior have any execution state (a core file
 768    does, an executable does not).  At present the code tests
 769    `target_has_stack' but I'm left wondering if it should test
 770    `target_has_registers' or, even, a merged target_has_state.
 771
 772    Should it look at the most recently specified SAL?  If the target
 773    has no state, should this function try to extract a block from the
 774    most recently selected SAL?  That way `list foo' would give it some
 775    sort of reference point.  Then again, perhaps that would confuse
 776    things.
 777
 778    Calls to this function can be broken down into two categories: Code
 779    that uses the selected block as an additional, but optional, data
 780    point; Code that uses the selected block as a prop, when it should
 781    have the relevant frame/block/pc explicitly passed in.
 782
 783    The latter can be eliminated by correctly parameterizing the code,
 784    the former though is more interesting.  Per the "address" command,
 785    it occurs in the CLI code and makes it possible for commands to
 786    work, even when the inferior has no state.  */
 787
 788 extern const struct block *get_selected_block (CORE_ADDR *addr_in_block);
 789
 790 extern struct symbol *get_frame_function (struct frame_info *);
 791
 792 extern CORE_ADDR get_pc_function_start (CORE_ADDR);
 793
 794 extern struct frame_info *find_relative_frame (struct frame_info *, int *);
 795
 796 /* Wrapper over print_stack_frame modifying current_uiout with UIOUT for
 797    the function call.  */
 798
 799 extern void print_stack_frame_to_uiout (struct ui_out *uiout,
 800                                         struct frame_info *, int print_level,
 801                                         enum print_what print_what,
 802                                         int set_current_sal);
 803
 804 extern void print_stack_frame (struct frame_info *, int print_level,
 805                                enum print_what print_what,
 806                                int set_current_sal);
 807
 808 extern void print_frame_info (const frame_print_options &fp_opts,
 809                               struct frame_info *, int print_level,
 810                               enum print_what print_what, int args,
 811                               int set_current_sal);
 812
 813 extern struct frame_info *block_innermost_frame (const struct block *);
 814
 815 extern bool deprecated_frame_register_read (frame_info *frame, int regnum,
 816                                             gdb_byte *buf);
 817
 818 /* From stack.c.  */
 819
 820 /* The possible choices of "set print frame-arguments".  */
 821 extern const char print_frame_arguments_all[];
 822 extern const char print_frame_arguments_scalars[];
 823 extern const char print_frame_arguments_none[];
 824
 825 /* The possible choices of "set print frame-info".  */
 826 extern const char print_frame_info_auto[];
 827 extern const char print_frame_info_source_line[];
 828 extern const char print_frame_info_location[];
 829 extern const char print_frame_info_source_and_location[];
 830 extern const char print_frame_info_location_and_address[];
 831 extern const char print_frame_info_short_location[];
 832
 833 /* The possible choices of "set print entry-values".  */
 834 extern const char print_entry_values_no[];
 835 extern const char print_entry_values_only[];
 836 extern const char print_entry_values_preferred[];
 837 extern const char print_entry_values_if_needed[];
 838 extern const char print_entry_values_both[];
 839 extern const char print_entry_values_compact[];
 840 extern const char print_entry_values_default[];
 841
 842 /* Data for the frame-printing "set print" settings exposed as command
 843    options.  */
 844
 845 struct frame_print_options
 846 {
 847   const char *print_frame_arguments = print_frame_arguments_scalars;
 848   const char *print_frame_info = print_frame_info_auto;
 849   const char *print_entry_values = print_entry_values_default;
 850
 851   /* If true, don't invoke pretty-printers for frame
 852      arguments.  */
 853   bool print_raw_frame_arguments;
 854 };
 855
 856 /* The values behind the global "set print ..." settings.  */
 857 extern frame_print_options user_frame_print_options;
 858
 859 /* Inferior function parameter value read in from a frame.  */
 860
 861 struct frame_arg
 862 {
 863   /* Symbol for this parameter used for example for its name.  */
 864   struct symbol *sym = nullptr;
 865
 866   /* Value of the parameter.  It is NULL if ERROR is not NULL; if both VAL and
 867      ERROR are NULL this parameter's value should not be printed.  */
 868   struct value *val = nullptr;
 869
 870   /* String containing the error message, it is more usually NULL indicating no
 871      error occured reading this parameter.  */
 872   gdb::unique_xmalloc_ptr<char> error;
 873
 874   /* One of the print_entry_values_* entries as appropriate specifically for
 875      this frame_arg.  It will be different from print_entry_values.  With
 876      print_entry_values_no this frame_arg should be printed as a normal
 877      parameter.  print_entry_values_only says it should be printed as entry
 878      value parameter.  print_entry_values_compact says it should be printed as
 879      both as a normal parameter and entry values parameter having the same
 880      value - print_entry_values_compact is not permitted fi ui_out_is_mi_like_p
 881      (in such case print_entry_values_no and print_entry_values_only is used
 882      for each parameter kind specifically.  */
 883   const char *entry_kind = nullptr;
 884 };
 885
 886 extern void read_frame_arg (const frame_print_options &fp_opts,
 887                             symbol *sym, frame_info *frame,
 888                             struct frame_arg *argp,
 889                             struct frame_arg *entryargp);
 890 extern void read_frame_local (struct symbol *sym, struct frame_info *frame,
 891                               struct frame_arg *argp);
 892
 893 extern void info_args_command (const char *, int);
 894
 895 extern void info_locals_command (const char *, int);
 896
 897 extern void return_command (const char *, int);
 898
 899 /* Set FRAME's unwinder temporarily, so that we can call a sniffer.
 900    If sniffing fails, the caller should be sure to call
 901    frame_cleanup_after_sniffer.  */
 902
 903 extern void frame_prepare_for_sniffer (struct frame_info *frame,
 904                                        const struct frame_unwind *unwind);
 905
 906 /* Clean up after a failed (wrong unwinder) attempt to unwind past
 907    FRAME.  */
 908
 909 extern void frame_cleanup_after_sniffer (struct frame_info *frame);
 910
 911 /* Notes (cagney/2002-11-27, drow/2003-09-06):
 912
 913    You might think that calls to this function can simply be replaced by a
 914    call to get_selected_frame().
 915
 916    Unfortunately, it isn't that easy.
 917
 918    The relevant code needs to be audited to determine if it is
 919    possible (or practical) to instead pass the applicable frame in as a
 920    parameter.  For instance, DEPRECATED_DO_REGISTERS_INFO() relied on
 921    the deprecated_selected_frame global, while its replacement,
 922    PRINT_REGISTERS_INFO(), is parameterized with the selected frame.
 923    The only real exceptions occur at the edge (in the CLI code) where
 924    user commands need to pick up the selected frame before proceeding.
 925
 926    There are also some functions called with a NULL frame meaning either "the
 927    program is not running" or "use the selected frame".
 928
 929    This is important.  GDB is trying to stamp out the hack:
 930
 931    saved_frame = deprecated_safe_get_selected_frame ();
 932    select_frame (...);
 933    hack_using_global_selected_frame ();
 934    select_frame (saved_frame);
 935
 936    Take care!
 937
 938    This function calls get_selected_frame if the inferior should have a
 939    frame, or returns NULL otherwise.  */
 940
 941 extern struct frame_info *deprecated_safe_get_selected_frame (void);
 942
 943 /* Create a frame using the specified BASE and PC.  */
 944
 945 extern struct frame_info *create_new_frame (CORE_ADDR base, CORE_ADDR pc);
 946
 947 /* Return true if the frame unwinder for frame FI is UNWINDER; false
 948    otherwise.  */
 949
 950 extern bool frame_unwinder_is (frame_info *fi, const frame_unwind *unwinder);
 951
 952 /* Return the language of FRAME.  */
 953
 954 extern enum language get_frame_language (struct frame_info *frame);
 955
 956 /* Return the first non-tailcall frame above FRAME or FRAME if it is not a
 957    tailcall frame.  Return NULL if FRAME is the start of a tailcall-only
 958    chain.  */
 959
 960 extern struct frame_info *skip_tailcall_frames (struct frame_info *frame);
 961
 962 /* Return the first frame above FRAME or FRAME of which the code is
 963    writable.  */
 964
 965 extern struct frame_info *skip_unwritable_frames (struct frame_info *frame);
 966
 967 /* Data for the "set backtrace" settings.  */
 968
 969 struct set_backtrace_options
 970 {
 971   /* Flag to indicate whether backtraces should continue past
 972      main.  */
 973   bool backtrace_past_main = false;
 974
 975   /* Flag to indicate whether backtraces should continue past
 976      entry.  */
 977   bool backtrace_past_entry = false;
 978
 979   /* Upper bound on the number of backtrace levels.  Note this is not
 980      exposed as a command option, because "backtrace" and "frame
 981      apply" already have other means to set a frame count limit.  */
 982   unsigned int backtrace_limit = UINT_MAX;
 983 };
 984
 985 /* The corresponding option definitions.  */
 986 extern const gdb::option::option_def set_backtrace_option_defs[2];
 987
 988 /* The values behind the global "set backtrace ..." settings.  */
 989 extern set_backtrace_options user_set_backtrace_options;
 990
 991 /* Get the number of calls to reinit_frame_cache.  */
 992
 993 unsigned int get_frame_cache_generation ();
 994
 995 /* Mark that the PC value is masked for the previous frame.  */
 996
 997 extern void set_frame_previous_pc_masked (struct frame_info *frame);
 998
 999 /* Get whether the PC value is masked for the given frame.  */
1000
1001 extern bool get_frame_pc_masked (const struct frame_info *frame);
1002
1003
1004 #endif /* !defined (FRAME_H)  */