/* Definitions for a frame unwinder, for GDB, the GNU debugger.
- Copyright (C) 2003, 2004 Free Software Foundation, Inc.
+ Copyright (C) 2003-2020 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
+ the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
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., 51 Franklin Street, Fifth Floor,
- Boston, MA 02110-1301, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#if !defined (FRAME_UNWIND_H)
#define FRAME_UNWIND_H 1
struct frame_unwind;
struct gdbarch;
struct regcache;
+struct value;
#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.
+ functions are called with this frame's `struct frame_info' and
+ prologue cache.
THIS frame's register values can be obtained by unwinding NEXT
frame's registers (a recursive operation).
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
+/* Given THIS frame, take a whiff of its registers (namely
the PC and attributes) and if SELF is the applicable unwinder,
- return non-zero. Possibly also initialize THIS_PROLOGUE_CACHE. */
+ return non-zero. Possibly also initialize THIS_PROLOGUE_CACHE; but
+ only if returning 1. Initializing THIS_PROLOGUE_CACHE in other
+ cases (0 return) is invalid. In case of exception, the caller has
+ to set *THIS_PROLOGUE_CACHE to NULL. */
typedef int (frame_sniffer_ftype) (const struct frame_unwind *self,
- struct frame_info *next_frame,
+ struct frame_info *this_frame,
void **this_prologue_cache);
+typedef enum unwind_stop_reason (frame_unwind_stop_reason_ftype)
+ (struct frame_info *this_frame, void **this_prologue_cache);
+
+/* A default frame sniffer which always accepts the frame. Used by
+ fallback prologue unwinders. */
+
+int default_frame_sniffer (const struct frame_unwind *self,
+ struct frame_info *this_frame,
+ void **this_prologue_cache);
+
+/* A default stop_reason callback which always claims the frame is
+ unwindable. */
+
+enum unwind_stop_reason
+ default_frame_unwind_stop_reason (struct frame_info *this_frame,
+ void **this_cache);
+
+/* A default unwind_pc callback that simply unwinds the register identified
+ by GDBARCH_PC_REGNUM. */
+
+extern CORE_ADDR default_unwind_pc (struct gdbarch *gdbarch,
+ struct frame_info *next_frame);
+
+/* A default unwind_sp callback that simply unwinds the register identified
+ by GDBARCH_SP_REGNUM. */
+
+extern CORE_ADDR default_unwind_sp (struct gdbarch *gdbarch,
+ struct frame_info *next_frame);
+
/* 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.
+ use THIS frame, and through it the NEXT frame's 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
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,
+typedef void (frame_this_id_ftype) (struct frame_info *this_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).
+ use THIS frame, and implicitly the NEXT frame's 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
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.
+ This function takes THIS_FRAME as an argument. It can find the
+ values of registers in THIS frame by calling get_frame_register
+ (THIS_FRAME), and reinvoke itself to find other registers in the
+ PREVIOUS frame by calling frame_unwind_register (THIS_FRAME).
- 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.
+ The result is a GDB value object describing the register value. It
+ may be a lazy reference to memory, a lazy reference to the value of
+ a register in THIS frame, or a non-lvalue.
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);
+typedef struct value * (frame_prev_register_ftype)
+ (struct frame_info *this_frame, void **this_prologue_cache,
+ int regnum);
-/* 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. */
+/* Deallocate extra memory associated with the frame cache if any. */
-typedef CORE_ADDR (frame_prev_pc_ftype) (struct frame_info *next_frame,
- void **this_prologue_cache);
+typedef void (frame_dealloc_cache_ftype) (struct frame_info *self,
+ void *this_cache);
+/* Assuming the frame chain: (outer) prev <-> this <-> next (inner);
+ use THIS frame, and implicitly the NEXT frame's register unwind
+ method, return PREV frame's architecture. */
+
+typedef struct gdbarch *(frame_prev_arch_ftype) (struct frame_info *this_frame,
+ void **this_prologue_cache);
struct frame_unwind
{
enum frame_type type;
/* Should an attribute indicating the frame's address-in-block go
here? */
+ frame_unwind_stop_reason_ftype *stop_reason;
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;
+ frame_dealloc_cache_ftype *dealloc_cache;
+ frame_prev_arch_ftype *prev_arch;
};
/* 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
+ to install 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);
+extern void frame_unwind_prepend_unwinder (struct gdbarch *,
+ const struct frame_unwind *);
/* 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);
+extern void frame_unwind_append_unwinder (struct gdbarch *gdbarch,
+ const struct frame_unwind *unwinder);
+
+/* Iterate through sniffers for THIS_FRAME frame until one returns with an
+ unwinder implementation. THIS_FRAME->UNWIND must be NULL, it will get set
+ by this function. Possibly initialize THIS_CACHE. */
+
+extern void frame_unwind_find_by_frame (struct frame_info *this_frame,
+ void **this_cache);
+
+/* Helper functions for value-based register unwinding. These return
+ a (possibly lazy) value of the appropriate type. */
+
+/* Return a value which indicates that FRAME did not save REGNUM. */
+
+struct value *frame_unwind_got_optimized (struct frame_info *frame,
+ int regnum);
+
+/* Return a value which indicates that FRAME copied REGNUM into
+ register NEW_REGNUM. */
+
+struct value *frame_unwind_got_register (struct frame_info *frame, int regnum,
+ int new_regnum);
+
+/* Return a value which indicates that FRAME saved REGNUM in memory at
+ ADDR. */
+
+struct value *frame_unwind_got_memory (struct frame_info *frame, int regnum,
+ CORE_ADDR addr);
+
+/* Return a value which indicates that FRAME's saved version of
+ REGNUM has a known constant (computed) value of VAL. */
+
+struct value *frame_unwind_got_constant (struct frame_info *frame, int regnum,
+ ULONGEST val);
+
+/* Return a value which indicates that FRAME's saved version of
+ REGNUM has a known constant (computed) value which is stored
+ inside BUF. */
+
+struct value *frame_unwind_got_bytes (struct frame_info *frame, int regnum,
+ gdb_byte *buf);
-/* Iterate through the next frame's sniffers until one returns with an
- unwinder implementation. Possibly initialize THIS_CACHE. */
+/* Return a value which indicates that FRAME's saved version of REGNUM
+ has a known constant (computed) value of ADDR. Convert the
+ CORE_ADDR to a target address if necessary. */
-extern const struct frame_unwind *frame_unwind_find_by_frame (struct frame_info *next_frame,
- void **this_cache);
+struct value *frame_unwind_got_address (struct frame_info *frame, int regnum,
+ CORE_ADDR addr);
#endif
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