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
  28 /* GENERIC DUMMY FRAMES
  29
  30    The following code serves to maintain the dummy stack frames for
  31    inferior function calls (ie. when gdb calls into the inferior via
  32    call_function_by_hand).  This code saves the machine state before
  33    the call in host memory, so we must maintain an independent stack
  34    and keep it consistant etc.  I am attempting to make this code
  35    generic enough to be used by many targets.
  36
  37    The cheapest and most generic way to do CALL_DUMMY on a new target
  38    is probably to define CALL_DUMMY to be empty, CALL_DUMMY_LENGTH to
  39    zero, and CALL_DUMMY_LOCATION to AT_ENTRY.  Then you must remember
  40    to define PUSH_RETURN_ADDRESS, because no call instruction will be
  41    being executed by the target.  Also FRAME_CHAIN_VALID as
  42    generic_{file,func}_frame_chain_valid and FIX_CALL_DUMMY as
  43    generic_fix_call_dummy.  */
  44
  45 /* Assuming that FRAME is a dummy, return a register value for the
  46    previous frame.  */
  47
  48 extern void dummy_frame_register_unwind (struct frame_info *frame,
  49                                          void **unwind_cache,
  50                                          int regnum,
  51                                          int *optimized,
  52                                          enum lval_type *lvalp,
  53                                          CORE_ADDR *addrp,
  54                                          int *realnump,
  55                                          void *valuep);
  56
  57 /* Assuming that FRAME is a dummy, return the resume address for the
  58    previous frame.  */
  59
  60 extern CORE_ADDR dummy_frame_pc_unwind (struct frame_info *frame,
  61                                         void **unwind_cache);
  62
  63 /* Does the PC fall in a dummy frame?
  64
  65    This function is used by "frame.c" when creating a new `struct
  66    frame_info'.
  67
  68    Note that there is also very similar code in breakpoint.c (where
  69    the bpstat stop reason is computed).  It is looking for a PC
  70    falling on a dummy_frame breakpoint.  Perhaphs this, and that code
  71    should be combined?
  72
  73    Architecture dependant code, that has access to a frame, should not
  74    use this function.  Instead (get_frame_type() == DUMMY_FRAME)
  75    should be used.
  76
  77    Hmm, but what about threads?  When the dummy-frame code tries to
  78    relocate a dummy frame's saved registers it definitly needs to
  79    differentiate between threads (otherwize it will do things like
  80    clean-up the wrong threads frames).  However, when just trying to
  81    identify a dummy-frame that shouldn't matter.  The wost that can
  82    happen is that a thread is marked as sitting in a dummy frame when,
  83    in reality, its corrupted its stack, to the point that a PC is
  84    pointing into a dummy frame.  */
  85
  86 extern int pc_in_dummy_frame (CORE_ADDR pc);
  87
  88 /* Return the regcache that belongs to the dummy-frame identifed by PC
  89    and FP, or NULL if no such frame exists.  */
  90 /* FIXME: cagney/2002-11-08: The function only exists because of
  91    deprecated_generic_get_saved_register.  Eliminate that function and
  92    this, to, can go.  */
  93
  94 extern struct regcache *generic_find_dummy_frame (CORE_ADDR pc,
  95                                                   CORE_ADDR fp);
  96 #endif /* !defined (DUMMY_FRAME_H)  */