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
)
100 struct cleanup
*old_cleanup
;
103 old_cleanup
= frame_prepare_for_sniffer (this_frame
, unwinder
);
107 res
= unwinder
->sniffer (unwinder
, this_frame
, this_cache
);
109 CATCH (ex
, RETURN_MASK_ALL
)
111 /* Catch all exceptions, caused by either interrupt or error.
112 Reset *THIS_CACHE. */
114 if (ex
.error
== NOT_AVAILABLE_ERROR
)
116 /* This usually means that not even the PC is available,
117 thus most unwinders aren't able to determine if they're
118 the best fit. Keep trying. Fallback prologue unwinders
119 should always accept the frame. */
120 do_cleanups (old_cleanup
);
123 throw_exception (ex
);
129 discard_cleanups (old_cleanup
);
134 /* Don't set *THIS_CACHE to NULL here, because sniffer has to do
136 do_cleanups (old_cleanup
);
139 gdb_assert_not_reached ("frame_unwind_try_unwinder");
142 /* Iterate through sniffers for THIS_FRAME frame until one returns with an
143 unwinder implementation. THIS_FRAME->UNWIND must be NULL, it will get set
144 by this function. Possibly initialize THIS_CACHE. */
147 frame_unwind_find_by_frame (struct frame_info
*this_frame
, void **this_cache
)
149 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
150 struct frame_unwind_table
*table
151 = (struct frame_unwind_table
*) gdbarch_data (gdbarch
, frame_unwind_data
);
152 struct frame_unwind_table_entry
*entry
;
153 const struct frame_unwind
*unwinder_from_target
;
155 unwinder_from_target
= target_get_unwinder ();
156 if (unwinder_from_target
!= NULL
157 && frame_unwind_try_unwinder (this_frame
, this_cache
,
158 unwinder_from_target
))
161 unwinder_from_target
= target_get_tailcall_unwinder ();
162 if (unwinder_from_target
!= NULL
163 && frame_unwind_try_unwinder (this_frame
, this_cache
,
164 unwinder_from_target
))
167 for (entry
= table
->list
; entry
!= NULL
; entry
= entry
->next
)
168 if (frame_unwind_try_unwinder (this_frame
, this_cache
, entry
->unwinder
))
171 internal_error (__FILE__
, __LINE__
, _("frame_unwind_find_by_frame failed"));
174 /* A default frame sniffer which always accepts the frame. Used by
175 fallback prologue unwinders. */
178 default_frame_sniffer (const struct frame_unwind
*self
,
179 struct frame_info
*this_frame
,
180 void **this_prologue_cache
)
185 /* The default frame unwinder stop_reason callback. */
187 enum unwind_stop_reason
188 default_frame_unwind_stop_reason (struct frame_info
*this_frame
,
191 struct frame_id this_id
= get_frame_id (this_frame
);
193 if (frame_id_eq (this_id
, outer_frame_id
))
194 return UNWIND_OUTERMOST
;
196 return UNWIND_NO_REASON
;
199 /* Helper functions for value-based register unwinding. These return
200 a (possibly lazy) value of the appropriate type. */
202 /* Return a value which indicates that FRAME did not save REGNUM. */
205 frame_unwind_got_optimized (struct frame_info
*frame
, int regnum
)
207 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
208 struct type
*type
= register_type (gdbarch
, regnum
);
211 /* Return an lval_register value, so that we print it as
213 val
= allocate_value_lazy (type
);
214 set_value_lazy (val
, 0);
215 mark_value_bytes_optimized_out (val
, 0, TYPE_LENGTH (type
));
216 VALUE_LVAL (val
) = lval_register
;
217 VALUE_REGNUM (val
) = regnum
;
218 VALUE_NEXT_FRAME_ID (val
)
219 = get_frame_id (get_next_frame_sentinel_okay (frame
));
223 /* Return a value which indicates that FRAME copied REGNUM into
224 register NEW_REGNUM. */
227 frame_unwind_got_register (struct frame_info
*frame
,
228 int regnum
, int new_regnum
)
230 return value_of_register_lazy (frame
, new_regnum
);
233 /* Return a value which indicates that FRAME saved REGNUM in memory at
237 frame_unwind_got_memory (struct frame_info
*frame
, int regnum
, CORE_ADDR addr
)
239 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
240 struct value
*v
= value_at_lazy (register_type (gdbarch
, regnum
), addr
);
242 set_value_stack (v
, 1);
246 /* Return a value which indicates that FRAME's saved version of
247 REGNUM has a known constant (computed) value of VAL. */
250 frame_unwind_got_constant (struct frame_info
*frame
, int regnum
,
253 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
254 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
255 struct value
*reg_val
;
257 reg_val
= value_zero (register_type (gdbarch
, regnum
), not_lval
);
258 store_unsigned_integer (value_contents_writeable (reg_val
),
259 register_size (gdbarch
, regnum
), byte_order
, val
);
264 frame_unwind_got_bytes (struct frame_info
*frame
, int regnum
, gdb_byte
*buf
)
266 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
267 struct value
*reg_val
;
269 reg_val
= value_zero (register_type (gdbarch
, regnum
), not_lval
);
270 memcpy (value_contents_raw (reg_val
), buf
, register_size (gdbarch
, regnum
));
274 /* Return a value which indicates that FRAME's saved version of REGNUM
275 has a known constant (computed) value of ADDR. Convert the
276 CORE_ADDR to a target address if necessary. */
279 frame_unwind_got_address (struct frame_info
*frame
, int regnum
,
282 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
283 struct value
*reg_val
;
285 reg_val
= value_zero (register_type (gdbarch
, regnum
), not_lval
);
286 pack_long (value_contents_writeable (reg_val
),
287 register_type (gdbarch
, regnum
), addr
);
292 _initialize_frame_unwind (void)
294 frame_unwind_data
= gdbarch_data_register_pre_init (frame_unwind_init
);
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