/* Definitions for a frame unwinder, for GDB, the GNU debugger.
- Copyright 2003 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., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, 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_data;
struct frame_info;
struct frame_id;
struct frame_unwind;
struct gdbarch;
struct regcache;
+struct value;
-/* Return the frame unwind methods for the function that contains PC,
- or NULL if this this unwinder can't handle this frame. */
+#include "frame.h" /* For enum frame_type. */
-typedef const struct frame_unwind *(frame_unwind_p_ftype) (CORE_ADDR pc);
+/* The following unwind functions assume a chain of frames forming the
+ sequence: (outer) prev <-> this <-> next (inner). All the
+ functions are called with this frame's `struct frame_info' and
+ prologue cache.
-/* 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. */
+ 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; 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 *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 void frame_unwind_append_predicate (struct gdbarch *gdbarch,
- frame_unwind_p_ftype *p);
+extern CORE_ADDR default_unwind_pc (struct gdbarch *gdbarch,
+ struct frame_info *next_frame);
-/* Iterate through the list of frame unwinders until one returns an
- implementation. */
+/* A default unwind_sp callback that simply unwinds the register identified
+ by GDBARCH_SP_REGNUM. */
-extern const struct frame_unwind *frame_unwind_find_by_pc (struct gdbarch
- *gdbarch,
- CORE_ADDR pc);
+extern CORE_ADDR default_unwind_sp (struct gdbarch *gdbarch,
+ struct frame_info *next_frame);
-/* 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.
+/* 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.
- 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().
+ 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.
- 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. */
+ 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.
-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);
+ 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.
-/* Same as for registers above, but return the address at which the
- calling frame would resume. */
+ 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 CORE_ADDR (frame_unwind_pc_ftype) (struct frame_info * frame,
- void **unwind_cache);
+typedef void (frame_this_id_ftype) (struct frame_info *this_frame,
+ void **this_prologue_cache,
+ struct frame_id *this_id);
-/* Same as for registers above, but return the ID of the frame that
- called this one. */
+/* 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).
-typedef void (frame_unwind_id_ftype) (struct frame_info * frame,
- void **unwind_cache,
- struct frame_id * id);
+ 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);
struct frame_unwind
{
- /* Should the frame's type go here? */
+ /* 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_unwind_pc_ftype *pc;
- frame_unwind_id_ftype *id;
- frame_unwind_reg_ftype *reg;
+ 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_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 more specific sigtramp unwinder that overrides the
+ traditional brute-force unwinder. */
+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_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);
+
+/* 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. */
+
+struct value *frame_unwind_got_address (struct frame_info *frame, int regnum,
+ CORE_ADDR addr);
+
#endif
projects / deliverable / binutils-gdb.git / blobdiff