binutils-gdb/gdb/trad-frame.h
John Baldwin 498f740792 Add a helper function to trad_frame to support register cache maps.
Currently, signal frame handlers require explicitly coded calls to
trad_frame_set_reg_addr() to describe the location of saved registers
within a signal frame.  This change permits the regcache_map_entry
arrays used with regcache::supply_regset and regcache::collect_regset
to be used to describe a block of saved registers given an initial
address for the register block.

Some systems use the same layout for registers in core dump notes,
native register sets with ptrace(), and the register contexts saved in
signal frames.  On these systems, a single register map can now be
used to describe the layout of registers in all three places.

If a register map entry's size does not match the native size of a
register, try to match the semantics used by
regcache::transfer_regset.  If a register slot is too large, assume
that the register's value is stored in the first N bytes and ignore
the remaning bytes.  If the register slot is smaller than the
register, assume the slot holds the low N bytes of the register's
value.  Read these low N bytes from the target and zero-extend them to
generate a register value.

While here, document the semantics for both regcache::transfer_regset
and trad_frame with respect to register slot's whose size does not
match the register's size.

gdb/ChangeLog:

	* regcache.h (struct regcache_map_entry): Note that this type can
	be used with traditional frame caches.
	* trad-frame.c (trad_frame_set_reg_regmap): New.
	* trad-frame.h (trad_frame_set_reg_regmap): New.
2018-10-08 14:47:33 -07:00

128 lines
4.7 KiB
C

/* Traditional frame unwind support, for GDB the GNU Debugger.
Copyright (C) 2003-2018 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 3 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, see <http://www.gnu.org/licenses/>. */
#ifndef TRAD_FRAME_H
#define TRAD_FRAME_H
#include "frame.h" /* For "struct frame_id". */
struct frame_info;
struct regcache_map_entry;
struct trad_frame_cache;
/* A simple, or traditional frame cache.
The entire cache is populated in a single pass and then generic
routines are used to extract the various cache values. */
struct trad_frame_cache *trad_frame_cache_zalloc (struct frame_info *);
/* This frame's ID. */
void trad_frame_set_id (struct trad_frame_cache *this_trad_cache,
struct frame_id this_id);
void trad_frame_get_id (struct trad_frame_cache *this_trad_cache,
struct frame_id *this_id);
void trad_frame_set_this_base (struct trad_frame_cache *this_trad_cache,
CORE_ADDR this_base);
CORE_ADDR trad_frame_get_this_base (struct trad_frame_cache *this_trad_cache);
void trad_frame_set_reg_realreg (struct trad_frame_cache *this_trad_cache,
int regnum, int realreg);
void trad_frame_set_reg_addr (struct trad_frame_cache *this_trad_cache,
int regnum, CORE_ADDR addr);
void trad_frame_set_reg_regmap (struct trad_frame_cache *this_trad_cache,
const struct regcache_map_entry *regmap,
CORE_ADDR addr, size_t size);
void trad_frame_set_reg_value (struct trad_frame_cache *this_cache,
int regnum, LONGEST val);
struct value *trad_frame_get_register (struct trad_frame_cache *this_trad_cache,
struct frame_info *this_frame,
int regnum);
/* A traditional saved regs table, indexed by REGNUM, encoding where
the value of REGNUM for the previous frame can be found in this
frame.
The table is initialized with an identity encoding (ADDR == -1,
REALREG == REGNUM) indicating that the value of REGNUM in the
previous frame can be found in register REGNUM (== REALREG) in this
frame.
The initial encoding can then be changed:
Modify ADDR (REALREG >= 0, ADDR != -1) to indicate that the value
of register REGNUM in the previous frame can be found in memory at
ADDR in this frame (addr_p, !realreg_p, !value_p).
Modify REALREG (REALREG >= 0, ADDR == -1) to indicate that the
value of register REGNUM in the previous frame is found in register
REALREG in this frame (!addr_p, realreg_p, !value_p).
Call trad_frame_set_value (REALREG == -1) to indicate that the
value of register REGNUM in the previous frame is found in ADDR
(!addr_p, !realreg_p, value_p).
Call trad_frame_set_unknown (REALREG == -2) to indicate that the
register's value is not known. */
struct trad_frame_saved_reg
{
LONGEST addr; /* A CORE_ADDR fits in a longest. */
int realreg;
};
/* Encode REGNUM value in the trad-frame. */
void trad_frame_set_value (struct trad_frame_saved_reg this_saved_regs[],
int regnum, LONGEST val);
/* Encode REGNUM is in REALREG in the trad-frame. */
void trad_frame_set_realreg (struct trad_frame_saved_reg this_saved_regs[],
int regnum, int realreg);
/* Encode REGNUM is at address ADDR in the trad-frame. */
void trad_frame_set_addr (struct trad_frame_saved_reg this_trad_cache[],
int regnum, CORE_ADDR addr);
/* Mark REGNUM as unknown. */
void trad_frame_set_unknown (struct trad_frame_saved_reg this_saved_regs[],
int regnum);
/* Convenience functions, return non-zero if the register has been
encoded as specified. */
int trad_frame_value_p (struct trad_frame_saved_reg this_saved_regs[],
int regnum);
int trad_frame_addr_p (struct trad_frame_saved_reg this_saved_regs[],
int regnum);
int trad_frame_realreg_p (struct trad_frame_saved_reg this_saved_regs[],
int regnum);
/* Return a freshly allocated (and initialized) trad_frame array. */
struct trad_frame_saved_reg *trad_frame_alloc_saved_regs (struct frame_info *);
struct trad_frame_saved_reg *trad_frame_alloc_saved_regs (struct gdbarch *);
/* Given the trad_frame info, return the location of the specified
register. */
struct value *trad_frame_get_prev_register (struct frame_info *this_frame,
struct trad_frame_saved_reg this_saved_regs[],
int regnum);
#endif