-/* Add a frame unwinder to the list. The predicates are polled in the
- order that they are appended. The initial list contains the dummy
- frame's predicate. */
-
-extern void frame_unwind_append_predicate (struct gdbarch *gdbarch,
- frame_unwind_p_ftype *p);
-
-/* Iterate through the list of frame unwinders until one returns an
- implementation. */
-
-extern const struct frame_unwind *frame_unwind_find_by_pc (struct gdbarch
- *gdbarch,
- CORE_ADDR pc);
-
-/* Return the location (and possibly value) of REGNUM for the previous
- (older, up) frame. All parameters except VALUEP can be assumed to
- be non NULL. When VALUEP is NULL, just the location of the
- register should be returned.
-
- UNWIND_CACHE is provided as mechanism for implementing a per-frame
- local cache. It's initial value being NULL. Memory for that cache
- should be allocated using frame_obstack_zalloc().
-
- Register window architectures (eg SPARC) should note that REGNUM
- identifies the register for the previous frame. For instance, a
- request for the value of "o1" for the previous frame would be found
- in the register "i1" in this FRAME. */
-
-typedef void (frame_unwind_reg_ftype) (struct frame_info * frame,
- void **unwind_cache,
- int regnum,
- int *optimized,
- enum lval_type * lvalp,
- CORE_ADDR *addrp,
- int *realnump, void *valuep);
-
-/* Same as for registers above, but return the address at which the
- calling frame would resume. */
-
-typedef CORE_ADDR (frame_unwind_pc_ftype) (struct frame_info * frame,
- void **unwind_cache);
-
-/* Same as for registers above, but return the ID of the frame that
- called this one. */
-
-typedef void (frame_unwind_id_ftype) (struct frame_info * frame,
- void **unwind_cache,
- struct frame_id * id);
-
-/* Discard the frame by restoring the registers (in regcache) back to
- that of the caller. */
-/* NOTE: cagney/2003-01-19: While at present the callers all pop each
- frame in turn, the implementor should try to code things so that
- any frame can be popped directly. */
-/* FIXME: cagney/2003-01-19: Since both FRAME and REGCACHE refer to a
- common register cache, care must be taken when restoring the
- registers. The `correct fix' is to first first save the registers
- in a scratch cache, and second write that scratch cache back to to
- the real register cache. */
-
-typedef void (frame_unwind_pop_ftype) (struct frame_info *frame,
- void **unwind_cache,
- struct regcache *regcache);
+ 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 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. */
+
+typedef int (frame_sniffer_ftype) (const struct frame_unwind *self,
+ 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);
+
+/* Assuming the frame chain: (outer) prev <-> this <-> next (inner);
+ 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
+ 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 *this_frame,
+ void **this_prologue_cache,
+ struct frame_id *this_id);
+
+/* Assuming the frame chain: (outer) prev <-> this <-> next (inner);
+ 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
+ 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.
+
+ 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).
+
+ 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 struct value * (frame_prev_register_ftype)
+ (struct frame_info *this_frame, void **this_prologue_cache,
+ int regnum);
+
+/* Deallocate extra memory associated with the frame cache if any. */
+
+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);