1 /* Definitions for frame unwinder, for GDB, the GNU debugger.
3 Copyright (C) 2003-2017 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"
30 static struct gdbarch_data
*frame_unwind_data
;
32 struct frame_unwind_table_entry
34 const struct frame_unwind
*unwinder
;
35 struct frame_unwind_table_entry
*next
;
38 struct frame_unwind_table
40 struct frame_unwind_table_entry
*list
;
41 /* The head of the OSABI part of the search list. */
42 struct frame_unwind_table_entry
**osabi_head
;
46 frame_unwind_init (struct obstack
*obstack
)
48 struct frame_unwind_table
*table
49 = OBSTACK_ZALLOC (obstack
, struct frame_unwind_table
);
51 /* Start the table out with a few default sniffers. OSABI code
52 can't override this. */
53 table
->list
= OBSTACK_ZALLOC (obstack
, struct frame_unwind_table_entry
);
54 table
->list
->unwinder
= &dummy_frame_unwind
;
55 table
->list
->next
= OBSTACK_ZALLOC (obstack
,
56 struct frame_unwind_table_entry
);
57 table
->list
->next
->unwinder
= &inline_frame_unwind
;
58 /* The insertion point for OSABI sniffers. */
59 table
->osabi_head
= &table
->list
->next
->next
;
64 frame_unwind_prepend_unwinder (struct gdbarch
*gdbarch
,
65 const struct frame_unwind
*unwinder
)
67 struct frame_unwind_table
*table
68 = (struct frame_unwind_table
*) gdbarch_data (gdbarch
, frame_unwind_data
);
69 struct frame_unwind_table_entry
*entry
;
71 /* Insert the new entry at the start of the list. */
72 entry
= GDBARCH_OBSTACK_ZALLOC (gdbarch
, struct frame_unwind_table_entry
);
73 entry
->unwinder
= unwinder
;
74 entry
->next
= (*table
->osabi_head
);
75 (*table
->osabi_head
) = entry
;
79 frame_unwind_append_unwinder (struct gdbarch
*gdbarch
,
80 const struct frame_unwind
*unwinder
)
82 struct frame_unwind_table
*table
83 = (struct frame_unwind_table
*) gdbarch_data (gdbarch
, frame_unwind_data
);
84 struct frame_unwind_table_entry
**ip
;
86 /* Find the end of the list and insert the new entry there. */
87 for (ip
= table
->osabi_head
; (*ip
) != NULL
; ip
= &(*ip
)->next
);
88 (*ip
) = GDBARCH_OBSTACK_ZALLOC (gdbarch
, struct frame_unwind_table_entry
);
89 (*ip
)->unwinder
= unwinder
;
92 /* Call SNIFFER from UNWINDER. If it succeeded set UNWINDER for
93 THIS_FRAME and return 1. Otherwise the function keeps THIS_FRAME
94 unchanged and returns 0. */
97 frame_unwind_try_unwinder (struct frame_info
*this_frame
, void **this_cache
,
98 const struct frame_unwind
*unwinder
)
102 frame_prepare_for_sniffer (this_frame
, unwinder
);
106 res
= unwinder
->sniffer (unwinder
, this_frame
, this_cache
);
108 CATCH (ex
, RETURN_MASK_ALL
)
110 /* Catch all exceptions, caused by either interrupt or error.
111 Reset *THIS_CACHE. */
113 if (ex
.error
== NOT_AVAILABLE_ERROR
)
115 /* This usually means that not even the PC is available,
116 thus most unwinders aren't able to determine if they're
117 the best fit. Keep trying. Fallback prologue unwinders
118 should always accept the frame. */
119 frame_cleanup_after_sniffer (this_frame
);
122 throw_exception (ex
);
130 /* Don't set *THIS_CACHE to NULL here, because sniffer has to do
132 frame_cleanup_after_sniffer (this_frame
);
135 gdb_assert_not_reached ("frame_unwind_try_unwinder");
138 /* Iterate through sniffers for THIS_FRAME frame until one returns with an
139 unwinder implementation. THIS_FRAME->UNWIND must be NULL, it will get set
140 by this function. Possibly initialize THIS_CACHE. */
143 frame_unwind_find_by_frame (struct frame_info
*this_frame
, void **this_cache
)
145 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
146 struct frame_unwind_table
*table
147 = (struct frame_unwind_table
*) gdbarch_data (gdbarch
, frame_unwind_data
);
148 struct frame_unwind_table_entry
*entry
;
149 const struct frame_unwind
*unwinder_from_target
;
151 unwinder_from_target
= target_get_unwinder ();
152 if (unwinder_from_target
!= NULL
153 && frame_unwind_try_unwinder (this_frame
, this_cache
,
154 unwinder_from_target
))
157 unwinder_from_target
= target_get_tailcall_unwinder ();
158 if (unwinder_from_target
!= NULL
159 && frame_unwind_try_unwinder (this_frame
, this_cache
,
160 unwinder_from_target
))
163 for (entry
= table
->list
; entry
!= NULL
; entry
= entry
->next
)
164 if (frame_unwind_try_unwinder (this_frame
, this_cache
, entry
->unwinder
))
167 internal_error (__FILE__
, __LINE__
, _("frame_unwind_find_by_frame failed"));
170 /* A default frame sniffer which always accepts the frame. Used by
171 fallback prologue unwinders. */
174 default_frame_sniffer (const struct frame_unwind
*self
,
175 struct frame_info
*this_frame
,
176 void **this_prologue_cache
)
181 /* The default frame unwinder stop_reason callback. */
183 enum unwind_stop_reason
184 default_frame_unwind_stop_reason (struct frame_info
*this_frame
,
187 struct frame_id this_id
= get_frame_id (this_frame
);
189 if (frame_id_eq (this_id
, outer_frame_id
))
190 return UNWIND_OUTERMOST
;
192 return UNWIND_NO_REASON
;
195 /* Helper functions for value-based register unwinding. These return
196 a (possibly lazy) value of the appropriate type. */
198 /* Return a value which indicates that FRAME did not save REGNUM. */
201 frame_unwind_got_optimized (struct frame_info
*frame
, int regnum
)
203 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
204 struct type
*type
= register_type (gdbarch
, regnum
);
207 /* Return an lval_register value, so that we print it as
209 val
= allocate_value_lazy (type
);
210 set_value_lazy (val
, 0);
211 mark_value_bytes_optimized_out (val
, 0, TYPE_LENGTH (type
));
212 VALUE_LVAL (val
) = lval_register
;
213 VALUE_REGNUM (val
) = regnum
;
214 VALUE_NEXT_FRAME_ID (val
)
215 = get_frame_id (get_next_frame_sentinel_okay (frame
));
219 /* Return a value which indicates that FRAME copied REGNUM into
220 register NEW_REGNUM. */
223 frame_unwind_got_register (struct frame_info
*frame
,
224 int regnum
, int new_regnum
)
226 return value_of_register_lazy (frame
, new_regnum
);
229 /* Return a value which indicates that FRAME saved REGNUM in memory at
233 frame_unwind_got_memory (struct frame_info
*frame
, int regnum
, CORE_ADDR addr
)
235 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
236 struct value
*v
= value_at_lazy (register_type (gdbarch
, regnum
), addr
);
238 set_value_stack (v
, 1);
242 /* Return a value which indicates that FRAME's saved version of
243 REGNUM has a known constant (computed) value of VAL. */
246 frame_unwind_got_constant (struct frame_info
*frame
, int regnum
,
249 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
250 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
251 struct value
*reg_val
;
253 reg_val
= value_zero (register_type (gdbarch
, regnum
), not_lval
);
254 store_unsigned_integer (value_contents_writeable (reg_val
),
255 register_size (gdbarch
, regnum
), byte_order
, val
);
260 frame_unwind_got_bytes (struct frame_info
*frame
, int regnum
, gdb_byte
*buf
)
262 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
263 struct value
*reg_val
;
265 reg_val
= value_zero (register_type (gdbarch
, regnum
), not_lval
);
266 memcpy (value_contents_raw (reg_val
), buf
, register_size (gdbarch
, regnum
));
270 /* Return a value which indicates that FRAME's saved version of REGNUM
271 has a known constant (computed) value of ADDR. Convert the
272 CORE_ADDR to a target address if necessary. */
275 frame_unwind_got_address (struct frame_info
*frame
, int regnum
,
278 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
279 struct value
*reg_val
;
281 reg_val
= value_zero (register_type (gdbarch
, regnum
), not_lval
);
282 pack_long (value_contents_writeable (reg_val
),
283 register_type (gdbarch
, regnum
), addr
);
288 _initialize_frame_unwind (void)
290 frame_unwind_data
= gdbarch_data_register_pre_init (frame_unwind_init
);
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