172 lines
6.9 KiB
C
172 lines
6.9 KiB
C
/* Definitions for a frame unwinder, for GDB, the GNU debugger.
|
|
|
|
Copyright 2003, 2004 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 (FRAME_UNWIND_H)
|
|
#define FRAME_UNWIND_H 1
|
|
|
|
struct frame_data;
|
|
struct frame_info;
|
|
struct frame_id;
|
|
struct frame_unwind;
|
|
struct gdbarch;
|
|
struct regcache;
|
|
|
|
#include "frame.h" /* For enum frame_type. */
|
|
|
|
/* The following unwind functions assume a chain of frames forming the
|
|
sequence: (outer) prev <-> this <-> next (inner). All the
|
|
functions are called with called with the next frame's `struct
|
|
frame_info' and and this frame's prologue cache.
|
|
|
|
THIS frame's register values can be obtained by unwinding NEXT
|
|
frame's registers (a recursive operation).
|
|
|
|
THIS frame's prologue cache can be used to cache information such
|
|
as where this frame's prologue stores the previous frame's
|
|
registers. */
|
|
|
|
/* Given the NEXT frame, take a wiff of THIS frame's registers (namely
|
|
the PC and attributes) and if SELF is the applicable unwinder,
|
|
return non-zero. Possibly also initialize THIS_PROLOGUE_CACHE. */
|
|
|
|
typedef int (frame_sniffer_ftype) (const struct frame_unwind *self,
|
|
struct frame_info *next_frame,
|
|
void **this_prologue_cache);
|
|
|
|
/* Assuming the frame chain: (outer) prev <-> this <-> next (inner);
|
|
use the NEXT frame, and its register unwind method, to determine
|
|
the frame ID of THIS frame.
|
|
|
|
A frame ID provides an invariant that can be used to re-identify an
|
|
instance of a frame. It is a combination of the frame's `base' and
|
|
the frame's function's code address.
|
|
|
|
Traditionally, THIS frame's ID was determined by examining THIS
|
|
frame's function's prologue, and identifying the register/offset
|
|
used as THIS frame's base.
|
|
|
|
Example: An examination of THIS frame's prologue reveals that, on
|
|
entry, it saves the PC(+12), SP(+8), and R1(+4) registers
|
|
(decrementing the SP by 12). Consequently, the frame ID's base can
|
|
be determined by adding 12 to the THIS frame's stack-pointer, and
|
|
the value of THIS frame's SP can be obtained by unwinding the NEXT
|
|
frame's SP.
|
|
|
|
THIS_PROLOGUE_CACHE can be used to share any prolog analysis data
|
|
with the other unwind methods. Memory for that cache should be
|
|
allocated using frame_obstack_zalloc(). */
|
|
|
|
typedef void (frame_this_id_ftype) (struct frame_info *next_frame,
|
|
void **this_prologue_cache,
|
|
struct frame_id *this_id);
|
|
|
|
/* Assuming the frame chain: (outer) prev <-> this <-> next (inner);
|
|
use the NEXT frame, and its register unwind method, to unwind THIS
|
|
frame's registers (returning the value of the specified register
|
|
REGNUM in the previous frame).
|
|
|
|
Traditionally, THIS frame's registers were unwound by examining
|
|
THIS frame's function's prologue and identifying which registers
|
|
that prolog code saved on the stack.
|
|
|
|
Example: An examination of THIS frame's prologue reveals that, on
|
|
entry, it saves the PC(+12), SP(+8), and R1(+4) registers
|
|
(decrementing the SP by 12). Consequently, the value of the PC
|
|
register in the previous frame is found in memory at SP+12, and
|
|
THIS frame's SP can be obtained by unwinding the NEXT frame's SP.
|
|
|
|
Why not pass in THIS_FRAME? By passing in NEXT frame and THIS
|
|
cache, the supplied parameters are consistent with the sibling
|
|
function THIS_ID.
|
|
|
|
Can the code call ``frame_register (get_prev_frame (NEXT_FRAME))''?
|
|
Won't the call frame_register (THIS_FRAME) be faster? Well,
|
|
ignoring the possability that the previous frame does not yet
|
|
exist, the ``frame_register (FRAME)'' function is expanded to
|
|
``frame_register_unwind (get_next_frame (FRAME)'' and hence that
|
|
call will expand to ``frame_register_unwind (get_next_frame
|
|
(get_prev_frame (NEXT_FRAME)))''. Might as well call
|
|
``frame_register_unwind (NEXT_FRAME)'' directly.
|
|
|
|
THIS_PROLOGUE_CACHE can be used to share any prolog analysis data
|
|
with the other unwind methods. Memory for that cache should be
|
|
allocated using frame_obstack_zalloc(). */
|
|
|
|
typedef void (frame_prev_register_ftype) (struct frame_info *next_frame,
|
|
void **this_prologue_cache,
|
|
int prev_regnum,
|
|
int *optimized,
|
|
enum lval_type * lvalp,
|
|
CORE_ADDR *addrp,
|
|
int *realnump, gdb_byte *valuep);
|
|
|
|
/* Assuming the frame chain: (outer) prev <-> this <-> next (inner);
|
|
use the NEXT frame, and its register unwind method, to return the PREV
|
|
frame's program-counter. */
|
|
|
|
typedef CORE_ADDR (frame_prev_pc_ftype) (struct frame_info *next_frame,
|
|
void **this_prologue_cache);
|
|
|
|
|
|
struct frame_unwind
|
|
{
|
|
/* The frame's type. Should this instead be a collection of
|
|
predicates that test the frame for various attributes? */
|
|
enum frame_type type;
|
|
/* Should an attribute indicating the frame's address-in-block go
|
|
here? */
|
|
frame_this_id_ftype *this_id;
|
|
frame_prev_register_ftype *prev_register;
|
|
const struct frame_data *unwind_data;
|
|
frame_sniffer_ftype *sniffer;
|
|
frame_prev_pc_ftype *prev_pc;
|
|
};
|
|
|
|
/* Register a frame unwinder, _prepending_ it to the front of the
|
|
search list (so it is sniffed before previously registered
|
|
unwinders). By using a prepend, later calls can install unwinders
|
|
that override earlier calls. This allows, for instance, an OSABI
|
|
to install a a more specific sigtramp unwinder that overrides the
|
|
traditional brute-force unwinder. */
|
|
extern void frame_unwind_prepend_unwinder (struct gdbarch *gdbarch,
|
|
const struct frame_unwind *unwinder);
|
|
|
|
/* Given the NEXT frame, take a wiff of THIS frame's registers (namely
|
|
the PC and attributes) and if it is the applicable unwinder return
|
|
the unwind methods, or NULL if it is not. */
|
|
|
|
typedef const struct frame_unwind *(frame_unwind_sniffer_ftype) (struct frame_info *next_frame);
|
|
|
|
/* Add a frame sniffer to the list. The predicates are polled in the
|
|
order that they are appended. The initial list contains the dummy
|
|
frame sniffer. */
|
|
|
|
extern void frame_unwind_append_sniffer (struct gdbarch *gdbarch,
|
|
frame_unwind_sniffer_ftype *sniffer);
|
|
|
|
/* Iterate through the next frame's sniffers until one returns with an
|
|
unwinder implementation. Possibly initialize THIS_CACHE. */
|
|
|
|
extern const struct frame_unwind *frame_unwind_find_by_frame (struct frame_info *next_frame,
|
|
void **this_cache);
|
|
|
|
#endif
|