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cbafadeb88
* sentinel-frame.c (sentinel_frame_prev_pc): New function. (sentinel_frame_unwinder): Add the prev_pc method. * frame.c (frame_pc_unwind): Use the per-frame pc unwinder when available. Do not handle the sentinel-frame case. * frame-unwind.h (frame_prev_register_ftype): Define. (struct frame_unwind): Add prev_pc;
172 lines
6.9 KiB
C
172 lines
6.9 KiB
C
/* Definitions for a frame unwinder, for GDB, the GNU debugger.
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Copyright 2003, 2004 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#if !defined (FRAME_UNWIND_H)
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#define FRAME_UNWIND_H 1
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struct frame_data;
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struct frame_info;
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struct frame_id;
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struct frame_unwind;
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struct gdbarch;
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struct regcache;
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#include "frame.h" /* For enum frame_type. */
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/* The following unwind functions assume a chain of frames forming the
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sequence: (outer) prev <-> this <-> next (inner). All the
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functions are called with called with the next frame's `struct
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frame_info' and and this frame's prologue cache.
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THIS frame's register values can be obtained by unwinding NEXT
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frame's registers (a recursive operation).
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THIS frame's prologue cache can be used to cache information such
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as where this frame's prologue stores the previous frame's
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registers. */
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/* Given the NEXT frame, take a wiff of THIS frame's registers (namely
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the PC and attributes) and if SELF is the applicable unwinder,
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return non-zero. Possibly also initialize THIS_PROLOGUE_CACHE. */
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typedef int (frame_sniffer_ftype) (const struct frame_unwind *self,
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struct frame_info *next_frame,
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void **this_prologue_cache);
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/* Assuming the frame chain: (outer) prev <-> this <-> next (inner);
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use the NEXT frame, and its register unwind method, to determine
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the frame ID of THIS frame.
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A frame ID provides an invariant that can be used to re-identify an
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instance of a frame. It is a combination of the frame's `base' and
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the frame's function's code address.
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Traditionally, THIS frame's ID was determined by examining THIS
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frame's function's prologue, and identifying the register/offset
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used as THIS frame's base.
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Example: An examination of THIS frame's prologue reveals that, on
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entry, it saves the PC(+12), SP(+8), and R1(+4) registers
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(decrementing the SP by 12). Consequently, the frame ID's base can
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be determined by adding 12 to the THIS frame's stack-pointer, and
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the value of THIS frame's SP can be obtained by unwinding the NEXT
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frame's SP.
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THIS_PROLOGUE_CACHE can be used to share any prolog analysis data
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with the other unwind methods. Memory for that cache should be
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allocated using frame_obstack_zalloc(). */
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typedef void (frame_this_id_ftype) (struct frame_info *next_frame,
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void **this_prologue_cache,
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struct frame_id *this_id);
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/* Assuming the frame chain: (outer) prev <-> this <-> next (inner);
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use the NEXT frame, and its register unwind method, to unwind THIS
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frame's registers (returning the value of the specified register
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REGNUM in the previous frame).
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Traditionally, THIS frame's registers were unwound by examining
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THIS frame's function's prologue and identifying which registers
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that prolog code saved on the stack.
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Example: An examination of THIS frame's prologue reveals that, on
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entry, it saves the PC(+12), SP(+8), and R1(+4) registers
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(decrementing the SP by 12). Consequently, the value of the PC
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register in the previous frame is found in memory at SP+12, and
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THIS frame's SP can be obtained by unwinding the NEXT frame's SP.
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Why not pass in THIS_FRAME? By passing in NEXT frame and THIS
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cache, the supplied parameters are consistent with the sibling
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function THIS_ID.
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Can the code call ``frame_register (get_prev_frame (NEXT_FRAME))''?
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Won't the call frame_register (THIS_FRAME) be faster? Well,
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ignoring the possability that the previous frame does not yet
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exist, the ``frame_register (FRAME)'' function is expanded to
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``frame_register_unwind (get_next_frame (FRAME)'' and hence that
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call will expand to ``frame_register_unwind (get_next_frame
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(get_prev_frame (NEXT_FRAME)))''. Might as well call
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``frame_register_unwind (NEXT_FRAME)'' directly.
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THIS_PROLOGUE_CACHE can be used to share any prolog analysis data
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with the other unwind methods. Memory for that cache should be
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allocated using frame_obstack_zalloc(). */
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typedef void (frame_prev_register_ftype) (struct frame_info *next_frame,
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void **this_prologue_cache,
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int prev_regnum,
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int *optimized,
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enum lval_type * lvalp,
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CORE_ADDR *addrp,
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int *realnump, void *valuep);
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/* Assuming the frame chain: (outer) prev <-> this <-> next (inner);
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use the NEXT frame, and its register unwind method, to return the PREV
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frame's program-counter. */
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typedef CORE_ADDR (frame_prev_pc_ftype) (struct frame_info *next_frame,
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void **this_prologue_cache);
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struct frame_unwind
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{
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/* The frame's type. Should this instead be a collection of
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predicates that test the frame for various attributes? */
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enum frame_type type;
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/* Should an attribute indicating the frame's address-in-block go
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here? */
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frame_this_id_ftype *this_id;
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frame_prev_register_ftype *prev_register;
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const struct frame_data *unwind_data;
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frame_sniffer_ftype *sniffer;
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frame_prev_pc_ftype *prev_pc;
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};
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/* Register a frame unwinder, _prepending_ it to the front of the
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search list (so it is sniffed before previously registered
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unwinders). By using a prepend, later calls can install unwinders
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that override earlier calls. This allows, for instance, an OSABI
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to install a a more specific sigtramp unwinder that overrides the
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traditional brute-force unwinder. */
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extern void frame_unwind_prepend_unwinder (struct gdbarch *gdbarch,
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const struct frame_unwind *unwinder);
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/* Given the NEXT frame, take a wiff of THIS frame's registers (namely
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the PC and attributes) and if it is the applicable unwinder return
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the unwind methods, or NULL if it is not. */
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typedef const struct frame_unwind *(frame_unwind_sniffer_ftype) (struct frame_info *next_frame);
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/* Add a frame sniffer to the list. The predicates are polled in the
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order that they are appended. The initial list contains the dummy
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frame sniffer. */
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extern void frame_unwind_append_sniffer (struct gdbarch *gdbarch,
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frame_unwind_sniffer_ftype *sniffer);
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/* Iterate through the next frame's sniffers until one returns with an
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unwinder implementation. Possibly initialize THIS_CACHE. */
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extern const struct frame_unwind *frame_unwind_find_by_frame (struct frame_info *next_frame,
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void **this_cache);
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#endif
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