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- /* Traditional frame unwind support, for GDB the GNU Debugger.
- Copyright (C) 2003-2022 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/>. */
- #include "defs.h"
- #include "frame.h"
- #include "trad-frame.h"
- #include "regcache.h"
- #include "frame-unwind.h"
- #include "target.h"
- #include "value.h"
- #include "gdbarch.h"
- #include "gdbsupport/traits.h"
- struct trad_frame_cache
- {
- struct frame_info *this_frame;
- CORE_ADDR this_base;
- trad_frame_saved_reg *prev_regs;
- struct frame_id this_id;
- };
- struct trad_frame_cache *
- trad_frame_cache_zalloc (struct frame_info *this_frame)
- {
- struct trad_frame_cache *this_trad_cache;
- this_trad_cache = FRAME_OBSTACK_ZALLOC (struct trad_frame_cache);
- this_trad_cache->prev_regs = trad_frame_alloc_saved_regs (this_frame);
- this_trad_cache->this_frame = this_frame;
- return this_trad_cache;
- }
- /* See trad-frame.h. */
- void
- trad_frame_reset_saved_regs (struct gdbarch *gdbarch,
- trad_frame_saved_reg *regs)
- {
- int numregs = gdbarch_num_cooked_regs (gdbarch);
- for (int regnum = 0; regnum < numregs; regnum++)
- regs[regnum].set_realreg (regnum);
- }
- trad_frame_saved_reg *
- trad_frame_alloc_saved_regs (struct gdbarch *gdbarch)
- {
- #ifdef HAVE_IS_TRIVIALLY_CONSTRUCTIBLE
- gdb_static_assert (std::is_trivially_constructible<trad_frame_saved_reg>::value);
- #endif
- int numregs = gdbarch_num_cooked_regs (gdbarch);
- trad_frame_saved_reg *this_saved_regs
- = FRAME_OBSTACK_CALLOC (numregs, trad_frame_saved_reg);
- /* For backwards compatibility, initialize all the register values to
- REALREG, with register 0 stored in 0, register 1 stored in 1 and so
- on. */
- trad_frame_reset_saved_regs (gdbarch, this_saved_regs);
- return this_saved_regs;
- }
- /* A traditional frame is unwound by analysing the function prologue
- and using the information gathered to track registers. For
- non-optimized frames, the technique is reliable (just need to check
- for all potential instruction sequences). */
- trad_frame_saved_reg *
- trad_frame_alloc_saved_regs (struct frame_info *this_frame)
- {
- struct gdbarch *gdbarch = get_frame_arch (this_frame);
- return trad_frame_alloc_saved_regs (gdbarch);
- }
- void
- trad_frame_set_reg_value (struct trad_frame_cache *this_trad_cache,
- int regnum, LONGEST val)
- {
- /* External interface for users of trad_frame_cache
- (who cannot access the prev_regs object directly). */
- this_trad_cache->prev_regs[regnum].set_value (val);
- }
- void
- trad_frame_set_reg_realreg (struct trad_frame_cache *this_trad_cache,
- int regnum, int realreg)
- {
- this_trad_cache->prev_regs[regnum].set_realreg (realreg);
- }
- void
- trad_frame_set_reg_addr (struct trad_frame_cache *this_trad_cache,
- int regnum, CORE_ADDR addr)
- {
- this_trad_cache->prev_regs[regnum].set_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)
- {
- struct gdbarch *gdbarch = get_frame_arch (this_trad_cache->this_frame);
- int offs = 0, count;
- for (; (count = regmap->count) != 0; regmap++)
- {
- int regno = regmap->regno;
- int slot_size = regmap->size;
- if (slot_size == 0 && regno != REGCACHE_MAP_SKIP)
- slot_size = register_size (gdbarch, regno);
- if (offs + slot_size > size)
- break;
- if (regno == REGCACHE_MAP_SKIP)
- offs += count * slot_size;
- else
- for (; count--; regno++, offs += slot_size)
- {
- /* Mimic the semantics of regcache::transfer_regset if a
- register slot's size does not match the size of a
- register.
- If a register slot is larger than a register, assume
- the register's value is stored in the first N bytes of
- the slot and ignore the remaining bytes.
- If the register slot is smaller than the register,
- assume that the slot contains the low N bytes of the
- register's value. Since trad_frame assumes that
- registers stored by address are sized according to the
- register, read the low N bytes and zero-extend them to
- generate a register value. */
- if (slot_size >= register_size (gdbarch, regno))
- trad_frame_set_reg_addr (this_trad_cache, regno, addr + offs);
- else
- {
- enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
- gdb_byte buf[slot_size];
- if (target_read_memory (addr + offs, buf, sizeof buf) == 0)
- {
- LONGEST val
- = extract_unsigned_integer (buf, sizeof buf, byte_order);
- trad_frame_set_reg_value (this_trad_cache, regno, val);
- }
- }
- }
- }
- }
- /* See trad-frame.h. */
- void
- trad_frame_set_reg_value_bytes (struct trad_frame_cache *this_trad_cache,
- int regnum,
- gdb::array_view<const gdb_byte> bytes)
- {
- /* External interface for users of trad_frame_cache
- (who cannot access the prev_regs object directly). */
- this_trad_cache->prev_regs[regnum].set_value_bytes (bytes);
- }
- struct value *
- trad_frame_get_prev_register (struct frame_info *this_frame,
- trad_frame_saved_reg this_saved_regs[],
- int regnum)
- {
- if (this_saved_regs[regnum].is_addr ())
- /* The register was saved in memory. */
- return frame_unwind_got_memory (this_frame, regnum,
- this_saved_regs[regnum].addr ());
- else if (this_saved_regs[regnum].is_realreg ())
- return frame_unwind_got_register (this_frame, regnum,
- this_saved_regs[regnum].realreg ());
- else if (this_saved_regs[regnum].is_value ())
- /* The register's value is available. */
- return frame_unwind_got_constant (this_frame, regnum,
- this_saved_regs[regnum].value ());
- else if (this_saved_regs[regnum].is_value_bytes ())
- /* The register's value is available as a sequence of bytes. */
- return frame_unwind_got_bytes (this_frame, regnum,
- this_saved_regs[regnum].value_bytes ());
- else
- return frame_unwind_got_optimized (this_frame, regnum);
- }
- struct value *
- trad_frame_get_register (struct trad_frame_cache *this_trad_cache,
- struct frame_info *this_frame,
- int regnum)
- {
- return trad_frame_get_prev_register (this_frame, this_trad_cache->prev_regs,
- regnum);
- }
- void
- trad_frame_set_id (struct trad_frame_cache *this_trad_cache,
- struct frame_id this_id)
- {
- this_trad_cache->this_id = this_id;
- }
- void
- trad_frame_get_id (struct trad_frame_cache *this_trad_cache,
- struct frame_id *this_id)
- {
- (*this_id) = this_trad_cache->this_id;
- }
- void
- trad_frame_set_this_base (struct trad_frame_cache *this_trad_cache,
- CORE_ADDR this_base)
- {
- this_trad_cache->this_base = this_base;
- }
- CORE_ADDR
- trad_frame_get_this_base (struct trad_frame_cache *this_trad_cache)
- {
- return this_trad_cache->this_base;
- }
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