[deliverable/binutils-gdb.git] / gdb / dummy-frame.h

/* Code dealing with dummy stack frames, for GDB, the GNU debugger.

   Copyright 2002 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#if !defined (DUMMY_FRAME_H)
#define DUMMY_FRAME_H 1

struct frame_info;
struct regcache;

/* GENERIC DUMMY FRAMES
  
   The following code serves to maintain the dummy stack frames for
   inferior function calls (ie. when gdb calls into the inferior via
   call_function_by_hand).  This code saves the machine state before
   the call in host memory, so we must maintain an independent stack
   and keep it consistant etc.  I am attempting to make this code
   generic enough to be used by many targets.
 
   The cheapest and most generic way to do CALL_DUMMY on a new target
   is probably to define CALL_DUMMY to be empty, CALL_DUMMY_LENGTH to
   zero, and CALL_DUMMY_LOCATION to AT_ENTRY.  Then you must remember
   to define PUSH_RETURN_ADDRESS, because no call instruction will be
   being executed by the target.  Also FRAME_CHAIN_VALID as
   generic_{file,func}_frame_chain_valid and FIX_CALL_DUMMY as
   generic_fix_call_dummy.  */

/* Assuming that FRAME is a dummy, return a register value for the
   previous frame.  */

extern void dummy_frame_register_unwind (struct frame_info *frame,
					 void **unwind_cache,
					 int regnum,
					 int *optimized,
					 enum lval_type *lvalp,
					 CORE_ADDR *addrp,
					 int *realnump,
					 void *valuep);

/* Assuming that FRAME is a dummy, return the resume address for the
   previous frame.  */

extern CORE_ADDR dummy_frame_pc_unwind (struct frame_info *frame,
					void **unwind_cache);

/* Does the PC fall in a dummy frame?

   This function is used by "frame.c" when creating a new `struct
   frame_info'.

   Note that there is also very similar code in breakpoint.c (where
   the bpstat stop reason is computed).  It is looking for a PC
   falling on a dummy_frame breakpoint.  Perhaphs this, and that code
   should be combined?

   Architecture dependant code, that has access to a frame, should not
   use this function.  Instead (get_frame_type() == DUMMY_FRAME)
   should be used.

   Hmm, but what about threads?  When the dummy-frame code tries to
   relocate a dummy frame's saved registers it definitly needs to
   differentiate between threads (otherwize it will do things like
   clean-up the wrong threads frames).  However, when just trying to
   identify a dummy-frame that shouldn't matter.  The wost that can
   happen is that a thread is marked as sitting in a dummy frame when,
   in reality, its corrupted its stack, to the point that a PC is
   pointing into a dummy frame.  */

extern int pc_in_dummy_frame (CORE_ADDR pc);

/* Return the regcache that belongs to the dummy-frame identifed by PC
   and FP, or NULL if no such frame exists.  */
/* FIXME: cagney/2002-11-08: The function only exists because of
   deprecated_generic_get_saved_register.  Eliminate that function and
   this, to, can go.  */

extern struct regcache *generic_find_dummy_frame (CORE_ADDR pc,
						  CORE_ADDR fp);
#endif /* !defined (DUMMY_FRAME_H)  */
Commit	Line	Data
9c1412c1 AC	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
8779790c AC	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);
9c1412c1	56
f18c5a73 AC	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
5e0f933e AC	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
9c1412c1 AC	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);
9c1412c1	96	#endif /* !defined (DUMMY_FRAME_H) */