* stabs.texinfo (Stack Variables): Re-write.

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

/* Definitions for dealing with stack frames, for GDB, the GNU debugger.
   Copyright 1986, 1989, 1991, 1992 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., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#if !defined (FRAME_H)
#define FRAME_H 1

/* A FRAME identifies a specific stack frame.  It is not constant over
   calls to the inferior (frame addresses are, see below).

   This is implemented as a "struct frame_info *".  This file and
   blockframe.c are the only places which are allowed to use the
   equivalence between FRAME and struct frame_info *.  Exception:
   Prototypes in other files use "struct frame_info *" because this
   file might not be included.

   The distinction between a FRAME and a "struct frame_info *" is made
   with the idea of maybe someday changing a FRAME to be something else,
   but seems to me that a "struct frame_info *" is fully general (since
   any necessarily fields can be added; changing the meaning of existing
   fields is not helped by the FRAME distinction), and this distinction
   merely creates unnecessary hair.  -kingdon, 18 May 93.  */
typedef struct frame_info *FRAME;

/* Convert from a "struct frame_info *" into a FRAME.  */
#define FRAME_INFO_ID(f)	(f)

/* Convert from a FRAME into a "struct frame_info *".  */
extern struct frame_info *
get_frame_info PARAMS ((FRAME));

/* Type of the address of a frame.  It is widely assumed (at least in
   prototypes in headers which might not include this header) that
   this is the same as CORE_ADDR, and no one can think of a case in
   which it wouldn't be, so it might be best to remove this typedef.  */
typedef CORE_ADDR	FRAME_ADDR;

/* Convert from a FRAME into a frame address.  Except in the
   machine-dependent *FRAME* macros, a frame address has no defined
   meaning other than as a magic cookie which identifies a frame over
   calls to the inferior.  The only known exception is inferior.h
   (PC_IN_CALL_DUMMY) [ON_STACK]; see comments there.  You cannot
   assume that a frame address contains enough information to
   reconstruct the frame; if you want more than just to identify the
   frame (e.g. be able to fetch variables relative to that frame),
   then save the whole struct frame_info (and the next struct
   frame_info, since the latter is used for fetching variables on some
   machines).  */

#define FRAME_FP(fr)	((fr)->frame)

/* We keep a cache of stack frames, each of which is a "struct
   frame_info".  The innermost one gets allocated (in
   wait_for_inferior) each time the inferior stops; current_frame
   points to it.  Additional frames get allocated (in
   get_prev_frame_info) as needed, and are chained through the next
   and prev fields.  Any time that the frame cache becomes invalid
   (most notably when we execute something, but also if we change how
   we interpret the frames (e.g. "set heuristic-fence-post" in
   mips-tdep.c, or anything which reads new symbols)), we should call
   reinit_frame_cache.  */

struct frame_info
  {
    /* Nominal address of the frame described.  See comments at FRAME_FP
       about what this means outside the *FRAME* macros; in the *FRAME*
       macros, it can mean whatever makes most sense for this machine.  */
    FRAME_ADDR frame;

    /* Address at which execution is occurring in this frame.
       For the innermost frame, it's the current pc.
       For other frames, it is a pc saved in the next frame.  */
    CORE_ADDR pc;

    /* Nonzero if this is a frame associated with calling a signal handler.

       Set by machine-dependent code.  On some machines, if
       the machine-dependent code fails to check for this, the backtrace
       will look relatively normal.  For example, on the i386
         #3  0x158728 in sighold ()
       On other machines (e.g. rs6000), the machine-dependent code better
       set this to prevent us from trying to print it like a normal frame.  */
    int signal_handler_caller;

    /* Anything extra for this structure that may have been defined
       in the machine depedent files. */
#ifdef EXTRA_FRAME_INFO
    EXTRA_FRAME_INFO
#endif

    /* We should probably also store a "struct frame_saved_regs" here.
       This is already done by some machines (e.g. config/m88k/tm-m88k.h)
       but there is no reason it couldn't be general.  */

    /* Pointers to the next and previous frame_info's in the frame cache.  */
    FRAME next, prev;
  };

/* Describe the saved registers of a frame.  */

struct frame_saved_regs
  {

    /* For each register, address of where it was saved on entry to
       the frame, or zero if it was not saved on entry to this frame.
       This includes special registers such as pc and fp saved in
       special ways in the stack frame.  The SP_REGNUM is even more
       special, the address here is the sp for the next frame, not the
       address where the sp was saved.  */

    CORE_ADDR regs[NUM_REGS];
  };

/* Define a default FRAME_CHAIN_VALID, in the form that is suitable for most
   targets.  If FRAME_CHAIN_VALID returns zero it means that the given frame
   is the outermost one and has no caller.

   If a particular target needs a different definition, then it can override
   the definition here by providing one in the tm file. */

#if !defined (FRAME_CHAIN_VALID)

#if defined (FRAME_CHAIN_VALID_ALTERNATE)

/* Use the alternate method of avoiding running up off the end of the frame
   chain or following frames back into the startup code.  See the comments
   in objfiles.h. */
   
#define FRAME_CHAIN_VALID(chain, thisframe)	\
  ((chain) != 0					\
   && !inside_main_func ((thisframe) -> pc)	\
   && !inside_entry_func ((thisframe) -> pc))

#else

#define FRAME_CHAIN_VALID(chain, thisframe)	\
  ((chain) != 0					\
   && !inside_entry_file (FRAME_SAVED_PC (thisframe)))

#endif	/* FRAME_CHAIN_VALID_ALTERNATE */

#endif	/* FRAME_CHAIN_VALID */

/* If we encounter a request to use base register addressing of variables
   on a machine for which gdb has not been configured to support such
   access, report the failure to support this access mode. */

#if !defined (FRAME_GET_BASEREG_VALUE)

#define FRAME_GET_BASEREG_VALUE(frame, regno) \
  (error ("Missing valid method for finding contents of base register."),0)

#endif

/* The stack frame that the user has specified for commands to act on.
   Note that one cannot assume this is the address of valid data.  */

extern FRAME selected_frame;

/* Level of the selected frame:
   0 for innermost, 1 for its caller, ...
   or -1 for frame specified by address with no defined level.  */

extern int selected_frame_level;

extern struct frame_info *
get_prev_frame_info PARAMS ((FRAME));

extern FRAME
create_new_frame PARAMS ((FRAME_ADDR, CORE_ADDR));

extern void
flush_cached_frames PARAMS ((void));

extern void
reinit_frame_cache PARAMS ((void));

extern void
get_frame_saved_regs PARAMS ((struct frame_info *, struct frame_saved_regs *));

extern void
set_current_frame PARAMS ((FRAME));

extern FRAME
get_prev_frame PARAMS ((FRAME));

extern FRAME
get_current_frame PARAMS ((void));

extern FRAME
get_next_frame PARAMS ((FRAME));

extern struct block *
get_frame_block PARAMS ((FRAME));

extern struct block *
get_current_block PARAMS ((void));

extern struct block *
get_selected_block PARAMS ((void));

extern struct symbol *
get_frame_function PARAMS ((FRAME));

extern CORE_ADDR
get_frame_pc PARAMS ((FRAME));

extern CORE_ADDR
get_pc_function_start PARAMS ((CORE_ADDR));

extern struct block *
block_for_pc PARAMS ((CORE_ADDR));

extern int
frameless_look_for_prologue PARAMS ((FRAME));

extern void
print_frame_args PARAMS ((struct symbol *, struct frame_info *, int, FILE *));

extern FRAME
find_relative_frame PARAMS ((FRAME, int*));

extern void
print_stack_frame PARAMS ((FRAME, int, int));

extern void
select_frame PARAMS ((FRAME, int));

extern void
record_selected_frame PARAMS ((FRAME_ADDR *, int *));

extern void
print_frame_info PARAMS ((struct frame_info *, int, int, int));

extern CORE_ADDR
find_saved_register PARAMS ((FRAME, int));

extern CORE_ADDR
sigtramp_saved_pc PARAMS ((FRAME));

#endif /* !defined (FRAME_H)  */