1 /* Traditional frame unwind support, for GDB the GNU Debugger.
3 Copyright (C) 2003-2018 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
22 #include "trad-frame.h"
24 #include "frame-unwind.h"
28 struct trad_frame_cache
30 struct frame_info
*this_frame
;
32 struct trad_frame_saved_reg
*prev_regs
;
33 struct frame_id this_id
;
36 struct trad_frame_cache
*
37 trad_frame_cache_zalloc (struct frame_info
*this_frame
)
39 struct trad_frame_cache
*this_trad_cache
;
41 this_trad_cache
= FRAME_OBSTACK_ZALLOC (struct trad_frame_cache
);
42 this_trad_cache
->prev_regs
= trad_frame_alloc_saved_regs (this_frame
);
43 this_trad_cache
->this_frame
= this_frame
;
44 return this_trad_cache
;
47 struct trad_frame_saved_reg
*
48 trad_frame_alloc_saved_regs (struct gdbarch
*gdbarch
)
51 int numregs
= gdbarch_num_regs (gdbarch
) + gdbarch_num_pseudo_regs (gdbarch
);
52 struct trad_frame_saved_reg
*this_saved_regs
53 = FRAME_OBSTACK_CALLOC (numregs
, struct trad_frame_saved_reg
);
55 for (regnum
= 0; regnum
< numregs
; regnum
++)
57 this_saved_regs
[regnum
].realreg
= regnum
;
58 this_saved_regs
[regnum
].addr
= -1;
60 return this_saved_regs
;
63 /* A traditional frame is unwound by analysing the function prologue
64 and using the information gathered to track registers. For
65 non-optimized frames, the technique is reliable (just need to check
66 for all potential instruction sequences). */
68 struct trad_frame_saved_reg
*
69 trad_frame_alloc_saved_regs (struct frame_info
*this_frame
)
71 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
73 return trad_frame_alloc_saved_regs (gdbarch
);
76 enum { TF_REG_VALUE
= -1, TF_REG_UNKNOWN
= -2 };
79 trad_frame_value_p (struct trad_frame_saved_reg this_saved_regs
[], int regnum
)
81 return (this_saved_regs
[regnum
].realreg
== TF_REG_VALUE
);
85 trad_frame_addr_p (struct trad_frame_saved_reg this_saved_regs
[], int regnum
)
87 return (this_saved_regs
[regnum
].realreg
>= 0
88 && this_saved_regs
[regnum
].addr
!= -1);
92 trad_frame_realreg_p (struct trad_frame_saved_reg this_saved_regs
[],
95 return (this_saved_regs
[regnum
].realreg
>= 0
96 && this_saved_regs
[regnum
].addr
== -1);
100 trad_frame_set_value (struct trad_frame_saved_reg this_saved_regs
[],
101 int regnum
, LONGEST val
)
103 /* Make the REALREG invalid, indicating that the ADDR contains the
105 this_saved_regs
[regnum
].realreg
= TF_REG_VALUE
;
106 this_saved_regs
[regnum
].addr
= val
;
109 /* See trad-frame.h. */
112 trad_frame_set_realreg (struct trad_frame_saved_reg this_saved_regs
[],
113 int regnum
, int realreg
)
115 this_saved_regs
[regnum
].realreg
= realreg
;
116 this_saved_regs
[regnum
].addr
= -1;
119 /* See trad-frame.h. */
122 trad_frame_set_addr (struct trad_frame_saved_reg this_saved_regs
[],
123 int regnum
, CORE_ADDR addr
)
125 this_saved_regs
[regnum
].realreg
= regnum
;
126 this_saved_regs
[regnum
].addr
= addr
;
130 trad_frame_set_reg_value (struct trad_frame_cache
*this_trad_cache
,
131 int regnum
, LONGEST val
)
133 /* External interface for users of trad_frame_cache
134 (who cannot access the prev_regs object directly). */
135 trad_frame_set_value (this_trad_cache
->prev_regs
, regnum
, val
);
139 trad_frame_set_reg_realreg (struct trad_frame_cache
*this_trad_cache
,
140 int regnum
, int realreg
)
142 trad_frame_set_realreg (this_trad_cache
->prev_regs
, regnum
, realreg
);
146 trad_frame_set_reg_addr (struct trad_frame_cache
*this_trad_cache
,
147 int regnum
, CORE_ADDR addr
)
149 trad_frame_set_addr (this_trad_cache
->prev_regs
, regnum
, addr
);
153 trad_frame_set_reg_regmap (struct trad_frame_cache
*this_trad_cache
,
154 const struct regcache_map_entry
*regmap
,
155 CORE_ADDR addr
, size_t size
)
157 struct gdbarch
*gdbarch
= get_frame_arch (this_trad_cache
->this_frame
);
160 for (; (count
= regmap
->count
) != 0; regmap
++)
162 int regno
= regmap
->regno
;
163 int slot_size
= regmap
->size
;
165 if (slot_size
== 0 && regno
!= REGCACHE_MAP_SKIP
)
166 slot_size
= register_size (gdbarch
, regno
);
168 if (offs
+ slot_size
> size
)
171 if (regno
== REGCACHE_MAP_SKIP
)
172 offs
+= count
* slot_size
;
174 for (; count
--; regno
++, offs
+= slot_size
)
176 /* Mimic the semantics of regcache::transfer_regset if a
177 register slot's size does not match the size of a
180 If a register slot is larger than a register, assume
181 the register's value is stored in the first N bytes of
182 the slot and ignore the remaining bytes.
184 If the register slot is smaller than the register,
185 assume that the slot contains the low N bytes of the
186 register's value. Since trad_frame assumes that
187 registers stored by address are sized according to the
188 register, read the low N bytes and zero-extend them to
189 generate a register value. */
190 if (slot_size
>= register_size (gdbarch
, regno
))
191 trad_frame_set_reg_addr (this_trad_cache
, regno
, addr
+ offs
);
194 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
195 gdb_byte buf
[slot_size
];
197 if (target_read_memory (addr
+ offs
, buf
, sizeof buf
) == 0)
200 = extract_unsigned_integer (buf
, sizeof buf
, byte_order
);
201 trad_frame_set_reg_value (this_trad_cache
, regno
, val
);
209 trad_frame_set_unknown (struct trad_frame_saved_reg this_saved_regs
[],
212 /* Make the REALREG invalid, indicating that the value is not known. */
213 this_saved_regs
[regnum
].realreg
= TF_REG_UNKNOWN
;
214 this_saved_regs
[regnum
].addr
= -1;
218 trad_frame_get_prev_register (struct frame_info
*this_frame
,
219 struct trad_frame_saved_reg this_saved_regs
[],
222 if (trad_frame_addr_p (this_saved_regs
, regnum
))
223 /* The register was saved in memory. */
224 return frame_unwind_got_memory (this_frame
, regnum
,
225 this_saved_regs
[regnum
].addr
);
226 else if (trad_frame_realreg_p (this_saved_regs
, regnum
))
227 return frame_unwind_got_register (this_frame
, regnum
,
228 this_saved_regs
[regnum
].realreg
);
229 else if (trad_frame_value_p (this_saved_regs
, regnum
))
230 /* The register's value is available. */
231 return frame_unwind_got_constant (this_frame
, regnum
,
232 this_saved_regs
[regnum
].addr
);
234 return frame_unwind_got_optimized (this_frame
, regnum
);
238 trad_frame_get_register (struct trad_frame_cache
*this_trad_cache
,
239 struct frame_info
*this_frame
,
242 return trad_frame_get_prev_register (this_frame
, this_trad_cache
->prev_regs
,
247 trad_frame_set_id (struct trad_frame_cache
*this_trad_cache
,
248 struct frame_id this_id
)
250 this_trad_cache
->this_id
= this_id
;
254 trad_frame_get_id (struct trad_frame_cache
*this_trad_cache
,
255 struct frame_id
*this_id
)
257 (*this_id
) = this_trad_cache
->this_id
;
261 trad_frame_set_this_base (struct trad_frame_cache
*this_trad_cache
,
264 this_trad_cache
->this_base
= this_base
;
268 trad_frame_get_this_base (struct trad_frame_cache
*this_trad_cache
)
270 return this_trad_cache
->this_base
;