gdb/dummy-frame.h

   1 /* Code dealing with dummy stack frames, for GDB, the GNU debugger.
   2
   3    Copyright 2002 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 2 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, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #if !defined (DUMMY_FRAME_H)
  23 #define DUMMY_FRAME_H 1
  24
  25 struct frame_info;
  26 struct regcache;
  27 struct frame_unwind;
  28 struct frame_id;
  29
  30 /* GENERIC DUMMY FRAMES
  31
  32    The following code serves to maintain the dummy stack frames for
  33    inferior function calls (ie. when gdb calls into the inferior via
  34    call_function_by_hand).  This code saves the machine state before
  35    the call in host memory, so we must maintain an independent stack
  36    and keep it consistant etc.  I am attempting to make this code
  37    generic enough to be used by many targets.
  38
  39    The cheapest and most generic way to do CALL_DUMMY on a new target
  40    is probably to define CALL_DUMMY to be empty, CALL_DUMMY_LENGTH to
  41    zero, and CALL_DUMMY_LOCATION to AT_ENTRY.  Then you must remember
  42    to define PUSH_RETURN_ADDRESS, because no call instruction will be
  43    being executed by the target.  Also DEPRECATED_FRAME_CHAIN_VALID as
  44    generic_{file,func}_frame_chain_valid and do not set
  45    FIX_CALL_DUMMY.  */
  46
  47 /* If the PC falls in a dummy frame, return a dummy frame
  48    unwinder.  */
  49
  50 extern const struct frame_unwind *dummy_frame_p (CORE_ADDR pc);
  51
  52 /* Does the PC fall in a dummy frame?
  53
  54    This function is used by "frame.c" when creating a new `struct
  55    frame_info'.
  56
  57    Note that there is also very similar code in breakpoint.c (where
  58    the bpstat stop reason is computed).  It is looking for a PC
  59    falling on a dummy_frame breakpoint.  Perhaphs this, and that code
  60    should be combined?
  61
  62    Architecture dependant code, that has access to a frame, should not
  63    use this function.  Instead (get_frame_type() == DUMMY_FRAME)
  64    should be used.
  65
  66    Hmm, but what about threads?  When the dummy-frame code tries to
  67    relocate a dummy frame's saved registers it definitly needs to
  68    differentiate between threads (otherwize it will do things like
  69    clean-up the wrong threads frames).  However, when just trying to
  70    identify a dummy-frame that shouldn't matter.  The wost that can
  71    happen is that a thread is marked as sitting in a dummy frame when,
  72    in reality, its corrupted its stack, to the point that a PC is
  73    pointing into a dummy frame.  */
  74
  75 extern int pc_in_dummy_frame (CORE_ADDR pc);
  76
  77 /* Return the regcache that belongs to the dummy-frame identifed by PC
  78    and FP, or NULL if no such frame exists.  */
  79 /* FIXME: cagney/2002-11-08: The function only exists because of
  80    deprecated_generic_get_saved_register.  Eliminate that function and
  81    this, to, can go.  */
  82
  83 extern struct regcache *generic_find_dummy_frame (CORE_ADDR pc,
  84                                                   CORE_ADDR fp);
  85 #endif /* !defined (DUMMY_FRAME_H)  */