1 /* Definitions for frame unwinder, for GDB, the GNU debugger.
3 Copyright (C) 2003-2020 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 "frame-unwind.h"
23 #include "dummy-frame.h"
24 #include "inline-frame.h"
27 #include "gdb_obstack.h"
31 static struct gdbarch_data
*frame_unwind_data
;
33 struct frame_unwind_table_entry
35 const struct frame_unwind
*unwinder
;
36 struct frame_unwind_table_entry
*next
;
39 struct frame_unwind_table
41 struct frame_unwind_table_entry
*list
;
42 /* The head of the OSABI part of the search list. */
43 struct frame_unwind_table_entry
**osabi_head
;
47 frame_unwind_init (struct obstack
*obstack
)
49 struct frame_unwind_table
*table
50 = OBSTACK_ZALLOC (obstack
, struct frame_unwind_table
);
52 /* Start the table out with a few default sniffers. OSABI code
53 can't override this. */
54 table
->list
= OBSTACK_ZALLOC (obstack
, struct frame_unwind_table_entry
);
55 table
->list
->unwinder
= &dummy_frame_unwind
;
56 table
->list
->next
= OBSTACK_ZALLOC (obstack
,
57 struct frame_unwind_table_entry
);
58 table
->list
->next
->unwinder
= &inline_frame_unwind
;
59 /* The insertion point for OSABI sniffers. */
60 table
->osabi_head
= &table
->list
->next
->next
;
65 frame_unwind_prepend_unwinder (struct gdbarch
*gdbarch
,
66 const struct frame_unwind
*unwinder
)
68 struct frame_unwind_table
*table
69 = (struct frame_unwind_table
*) gdbarch_data (gdbarch
, frame_unwind_data
);
70 struct frame_unwind_table_entry
*entry
;
72 /* Insert the new entry at the start of the list. */
73 entry
= GDBARCH_OBSTACK_ZALLOC (gdbarch
, struct frame_unwind_table_entry
);
74 entry
->unwinder
= unwinder
;
75 entry
->next
= (*table
->osabi_head
);
76 (*table
->osabi_head
) = entry
;
80 frame_unwind_append_unwinder (struct gdbarch
*gdbarch
,
81 const struct frame_unwind
*unwinder
)
83 struct frame_unwind_table
*table
84 = (struct frame_unwind_table
*) gdbarch_data (gdbarch
, frame_unwind_data
);
85 struct frame_unwind_table_entry
**ip
;
87 /* Find the end of the list and insert the new entry there. */
88 for (ip
= table
->osabi_head
; (*ip
) != NULL
; ip
= &(*ip
)->next
);
89 (*ip
) = GDBARCH_OBSTACK_ZALLOC (gdbarch
, struct frame_unwind_table_entry
);
90 (*ip
)->unwinder
= unwinder
;
93 /* Call SNIFFER from UNWINDER. If it succeeded set UNWINDER for
94 THIS_FRAME and return 1. Otherwise the function keeps THIS_FRAME
95 unchanged and returns 0. */
98 frame_unwind_try_unwinder (struct frame_info
*this_frame
, void **this_cache
,
99 const struct frame_unwind
*unwinder
)
103 frame_prepare_for_sniffer (this_frame
, unwinder
);
107 res
= unwinder
->sniffer (unwinder
, this_frame
, this_cache
);
109 catch (const gdb_exception
&ex
)
111 /* Catch all exceptions, caused by either interrupt or error.
112 Reset *THIS_CACHE. */
114 frame_cleanup_after_sniffer (this_frame
);
116 if (ex
.error
== NOT_AVAILABLE_ERROR
)
118 /* This usually means that not even the PC is available,
119 thus most unwinders aren't able to determine if they're
120 the best fit. Keep trying. Fallback prologue unwinders
121 should always accept the frame. */
131 /* Don't set *THIS_CACHE to NULL here, because sniffer has to do
133 frame_cleanup_after_sniffer (this_frame
);
136 gdb_assert_not_reached ("frame_unwind_try_unwinder");
139 /* Iterate through sniffers for THIS_FRAME frame until one returns with an
140 unwinder implementation. THIS_FRAME->UNWIND must be NULL, it will get set
141 by this function. Possibly initialize THIS_CACHE. */
144 frame_unwind_find_by_frame (struct frame_info
*this_frame
, void **this_cache
)
146 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
147 struct frame_unwind_table
*table
148 = (struct frame_unwind_table
*) gdbarch_data (gdbarch
, frame_unwind_data
);
149 struct frame_unwind_table_entry
*entry
;
150 const struct frame_unwind
*unwinder_from_target
;
152 unwinder_from_target
= target_get_unwinder ();
153 if (unwinder_from_target
!= NULL
154 && frame_unwind_try_unwinder (this_frame
, this_cache
,
155 unwinder_from_target
))
158 unwinder_from_target
= target_get_tailcall_unwinder ();
159 if (unwinder_from_target
!= NULL
160 && frame_unwind_try_unwinder (this_frame
, this_cache
,
161 unwinder_from_target
))
164 for (entry
= table
->list
; entry
!= NULL
; entry
= entry
->next
)
165 if (frame_unwind_try_unwinder (this_frame
, this_cache
, entry
->unwinder
))
168 internal_error (__FILE__
, __LINE__
, _("frame_unwind_find_by_frame failed"));
171 /* A default frame sniffer which always accepts the frame. Used by
172 fallback prologue unwinders. */
175 default_frame_sniffer (const struct frame_unwind
*self
,
176 struct frame_info
*this_frame
,
177 void **this_prologue_cache
)
182 /* The default frame unwinder stop_reason callback. */
184 enum unwind_stop_reason
185 default_frame_unwind_stop_reason (struct frame_info
*this_frame
,
188 struct frame_id this_id
= get_frame_id (this_frame
);
190 if (frame_id_eq (this_id
, outer_frame_id
))
191 return UNWIND_OUTERMOST
;
193 return UNWIND_NO_REASON
;
196 /* See frame-unwind.h. */
199 default_unwind_pc (struct gdbarch
*gdbarch
, struct frame_info
*next_frame
)
201 int pc_regnum
= gdbarch_pc_regnum (gdbarch
);
202 CORE_ADDR pc
= frame_unwind_register_unsigned (next_frame
, pc_regnum
);
203 pc
= gdbarch_addr_bits_remove (gdbarch
, pc
);
207 /* See frame-unwind.h. */
210 default_unwind_sp (struct gdbarch
*gdbarch
, struct frame_info
*next_frame
)
212 int sp_regnum
= gdbarch_sp_regnum (gdbarch
);
213 return frame_unwind_register_unsigned (next_frame
, sp_regnum
);
216 /* Helper functions for value-based register unwinding. These return
217 a (possibly lazy) value of the appropriate type. */
219 /* Return a value which indicates that FRAME did not save REGNUM. */
222 frame_unwind_got_optimized (struct frame_info
*frame
, int regnum
)
224 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
225 struct type
*type
= register_type (gdbarch
, regnum
);
228 /* Return an lval_register value, so that we print it as
230 val
= allocate_value_lazy (type
);
231 set_value_lazy (val
, 0);
232 mark_value_bytes_optimized_out (val
, 0, TYPE_LENGTH (type
));
233 VALUE_LVAL (val
) = lval_register
;
234 VALUE_REGNUM (val
) = regnum
;
235 VALUE_NEXT_FRAME_ID (val
)
236 = get_frame_id (get_next_frame_sentinel_okay (frame
));
240 /* Return a value which indicates that FRAME copied REGNUM into
241 register NEW_REGNUM. */
244 frame_unwind_got_register (struct frame_info
*frame
,
245 int regnum
, int new_regnum
)
247 return value_of_register_lazy (frame
, new_regnum
);
250 /* Return a value which indicates that FRAME saved REGNUM in memory at
254 frame_unwind_got_memory (struct frame_info
*frame
, int regnum
, CORE_ADDR addr
)
256 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
257 struct value
*v
= value_at_lazy (register_type (gdbarch
, regnum
), addr
);
259 set_value_stack (v
, 1);
263 /* Return a value which indicates that FRAME's saved version of
264 REGNUM has a known constant (computed) value of VAL. */
267 frame_unwind_got_constant (struct frame_info
*frame
, int regnum
,
270 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
271 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
272 struct value
*reg_val
;
274 reg_val
= value_zero (register_type (gdbarch
, regnum
), not_lval
);
275 store_unsigned_integer (value_contents_writeable (reg_val
),
276 register_size (gdbarch
, regnum
), byte_order
, val
);
281 frame_unwind_got_bytes (struct frame_info
*frame
, int regnum
, gdb_byte
*buf
)
283 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
284 struct value
*reg_val
;
286 reg_val
= value_zero (register_type (gdbarch
, regnum
), not_lval
);
287 memcpy (value_contents_raw (reg_val
), buf
, register_size (gdbarch
, regnum
));
291 /* Return a value which indicates that FRAME's saved version of REGNUM
292 has a known constant (computed) value of ADDR. Convert the
293 CORE_ADDR to a target address if necessary. */
296 frame_unwind_got_address (struct frame_info
*frame
, int regnum
,
299 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
300 struct value
*reg_val
;
302 reg_val
= value_zero (register_type (gdbarch
, regnum
), not_lval
);
303 pack_long (value_contents_writeable (reg_val
),
304 register_type (gdbarch
, regnum
), addr
);
309 _initialize_frame_unwind (void)
311 frame_unwind_data
= gdbarch_data_register_pre_init (frame_unwind_init
);
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