/* Traditional frame unwind support, for GDB the GNU Debugger. 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 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" struct trad_frame_cache { struct frame_info *this_frame; CORE_ADDR this_base; struct 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, struct trad_frame_saved_reg *regs) { int numregs = gdbarch_num_cooked_regs (gdbarch); for (int regnum = 0; regnum < numregs; regnum++) { regs[regnum].realreg = regnum; regs[regnum].addr = -1; } } struct trad_frame_saved_reg * trad_frame_alloc_saved_regs (struct gdbarch *gdbarch) { int numregs = gdbarch_num_cooked_regs (gdbarch); struct trad_frame_saved_reg *this_saved_regs = FRAME_OBSTACK_CALLOC (numregs, struct trad_frame_saved_reg); 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). */ struct 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); } enum { TF_REG_VALUE = -1, TF_REG_UNKNOWN = -2 }; int trad_frame_value_p (struct trad_frame_saved_reg this_saved_regs[], int regnum) { return (this_saved_regs[regnum].realreg == TF_REG_VALUE); } int trad_frame_addr_p (struct trad_frame_saved_reg this_saved_regs[], int regnum) { return (this_saved_regs[regnum].realreg >= 0 && this_saved_regs[regnum].addr != -1); } int trad_frame_realreg_p (struct trad_frame_saved_reg this_saved_regs[], int regnum) { return (this_saved_regs[regnum].realreg >= 0 && this_saved_regs[regnum].addr == -1); } void trad_frame_set_value (struct trad_frame_saved_reg this_saved_regs[], int regnum, LONGEST val) { /* Make the REALREG invalid, indicating that the ADDR contains the register's value. */ this_saved_regs[regnum].realreg = TF_REG_VALUE; this_saved_regs[regnum].addr = val; } /* See trad-frame.h. */ void trad_frame_set_realreg (struct trad_frame_saved_reg this_saved_regs[], int regnum, int realreg) { this_saved_regs[regnum].realreg = realreg; this_saved_regs[regnum].addr = -1; } /* See trad-frame.h. */ void trad_frame_set_addr (struct trad_frame_saved_reg this_saved_regs[], int regnum, CORE_ADDR addr) { this_saved_regs[regnum].realreg = regnum; this_saved_regs[regnum].addr = addr; } 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). */ trad_frame_set_value (this_trad_cache->prev_regs, regnum, val); } void trad_frame_set_reg_realreg (struct trad_frame_cache *this_trad_cache, int regnum, int realreg) { trad_frame_set_realreg (this_trad_cache->prev_regs, regnum, realreg); } void trad_frame_set_reg_addr (struct trad_frame_cache *this_trad_cache, int regnum, CORE_ADDR addr) { trad_frame_set_addr (this_trad_cache->prev_regs, regnum, 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); } } } } } void trad_frame_set_unknown (struct trad_frame_saved_reg this_saved_regs[], int regnum) { /* Make the REALREG invalid, indicating that the value is not known. */ this_saved_regs[regnum].realreg = TF_REG_UNKNOWN; this_saved_regs[regnum].addr = -1; } struct value * trad_frame_get_prev_register (struct frame_info *this_frame, struct trad_frame_saved_reg this_saved_regs[], int regnum) { if (trad_frame_addr_p (this_saved_regs, regnum)) /* The register was saved in memory. */ return frame_unwind_got_memory (this_frame, regnum, this_saved_regs[regnum].addr); else if (trad_frame_realreg_p (this_saved_regs, regnum)) return frame_unwind_got_register (this_frame, regnum, this_saved_regs[regnum].realreg); else if (trad_frame_value_p (this_saved_regs, regnum)) /* The register's value is available. */ return frame_unwind_got_constant (this_frame, regnum, this_saved_regs[regnum].addr); 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; }