1 /* Definitions for frame unwinder, for GDB, the GNU debugger.
3 Copyright (C) 2003-2015 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
= gdbarch_data (gdbarch
, frame_unwind_data
);
68 struct frame_unwind_table_entry
*entry
;
70 /* Insert the new entry at the start of the list. */
71 entry
= GDBARCH_OBSTACK_ZALLOC (gdbarch
, struct frame_unwind_table_entry
);
72 entry
->unwinder
= unwinder
;
73 entry
->next
= (*table
->osabi_head
);
74 (*table
->osabi_head
) = entry
;
78 frame_unwind_append_unwinder (struct gdbarch
*gdbarch
,
79 const struct frame_unwind
*unwinder
)
81 struct frame_unwind_table
*table
= gdbarch_data (gdbarch
, frame_unwind_data
);
82 struct frame_unwind_table_entry
**ip
;
84 /* Find the end of the list and insert the new entry there. */
85 for (ip
= table
->osabi_head
; (*ip
) != NULL
; ip
= &(*ip
)->next
);
86 (*ip
) = GDBARCH_OBSTACK_ZALLOC (gdbarch
, struct frame_unwind_table_entry
);
87 (*ip
)->unwinder
= unwinder
;
90 /* Call SNIFFER from UNWINDER. If it succeeded set UNWINDER for
91 THIS_FRAME and return 1. Otherwise the function keeps THIS_FRAME
92 unchanged and returns 0. */
95 frame_unwind_try_unwinder (struct frame_info
*this_frame
, void **this_cache
,
96 const struct frame_unwind
*unwinder
)
98 struct cleanup
*old_cleanup
;
99 volatile struct gdb_exception ex
;
102 old_cleanup
= frame_prepare_for_sniffer (this_frame
, unwinder
);
104 TRY_CATCH (ex
, RETURN_MASK_ERROR
)
106 res
= unwinder
->sniffer (unwinder
, this_frame
, this_cache
);
108 if (ex
.reason
< 0 && ex
.error
== NOT_AVAILABLE_ERROR
)
110 /* This usually means that not even the PC is available,
111 thus most unwinders aren't able to determine if they're
112 the best fit. Keep trying. Fallback prologue unwinders
113 should always accept the frame. */
114 do_cleanups (old_cleanup
);
117 else if (ex
.reason
< 0)
118 throw_exception (ex
);
121 discard_cleanups (old_cleanup
);
126 do_cleanups (old_cleanup
);
129 gdb_assert_not_reached ("frame_unwind_try_unwinder");
132 /* Iterate through sniffers for THIS_FRAME frame until one returns with an
133 unwinder implementation. THIS_FRAME->UNWIND must be NULL, it will get set
134 by this function. Possibly initialize THIS_CACHE. */
137 frame_unwind_find_by_frame (struct frame_info
*this_frame
, void **this_cache
)
139 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
140 struct frame_unwind_table
*table
= gdbarch_data (gdbarch
, frame_unwind_data
);
141 struct frame_unwind_table_entry
*entry
;
142 const struct frame_unwind
*unwinder_from_target
;
144 unwinder_from_target
= target_get_unwinder ();
145 if (unwinder_from_target
!= NULL
146 && frame_unwind_try_unwinder (this_frame
, this_cache
,
147 unwinder_from_target
))
150 unwinder_from_target
= target_get_tailcall_unwinder ();
151 if (unwinder_from_target
!= NULL
152 && frame_unwind_try_unwinder (this_frame
, this_cache
,
153 unwinder_from_target
))
156 for (entry
= table
->list
; entry
!= NULL
; entry
= entry
->next
)
157 if (frame_unwind_try_unwinder (this_frame
, this_cache
, entry
->unwinder
))
160 internal_error (__FILE__
, __LINE__
, _("frame_unwind_find_by_frame failed"));
163 /* A default frame sniffer which always accepts the frame. Used by
164 fallback prologue unwinders. */
167 default_frame_sniffer (const struct frame_unwind
*self
,
168 struct frame_info
*this_frame
,
169 void **this_prologue_cache
)
174 /* The default frame unwinder stop_reason callback. */
176 enum unwind_stop_reason
177 default_frame_unwind_stop_reason (struct frame_info
*this_frame
,
180 struct frame_id this_id
= get_frame_id (this_frame
);
182 if (frame_id_eq (this_id
, outer_frame_id
))
183 return UNWIND_OUTERMOST
;
185 return UNWIND_NO_REASON
;
188 /* Helper functions for value-based register unwinding. These return
189 a (possibly lazy) value of the appropriate type. */
191 /* Return a value which indicates that FRAME did not save REGNUM. */
194 frame_unwind_got_optimized (struct frame_info
*frame
, int regnum
)
196 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
197 struct type
*type
= register_type (gdbarch
, regnum
);
200 /* Return an lval_register value, so that we print it as
202 val
= allocate_value_lazy (type
);
203 set_value_lazy (val
, 0);
204 mark_value_bytes_optimized_out (val
, 0, TYPE_LENGTH (type
));
205 VALUE_LVAL (val
) = lval_register
;
206 VALUE_REGNUM (val
) = regnum
;
207 VALUE_FRAME_ID (val
) = get_frame_id (frame
);
211 /* Return a value which indicates that FRAME copied REGNUM into
212 register NEW_REGNUM. */
215 frame_unwind_got_register (struct frame_info
*frame
,
216 int regnum
, int new_regnum
)
218 return value_of_register_lazy (frame
, new_regnum
);
221 /* Return a value which indicates that FRAME saved REGNUM in memory at
225 frame_unwind_got_memory (struct frame_info
*frame
, int regnum
, CORE_ADDR addr
)
227 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
228 struct value
*v
= value_at_lazy (register_type (gdbarch
, regnum
), addr
);
230 set_value_stack (v
, 1);
234 /* Return a value which indicates that FRAME's saved version of
235 REGNUM has a known constant (computed) value of VAL. */
238 frame_unwind_got_constant (struct frame_info
*frame
, int regnum
,
241 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
242 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
243 struct value
*reg_val
;
245 reg_val
= value_zero (register_type (gdbarch
, regnum
), not_lval
);
246 store_unsigned_integer (value_contents_writeable (reg_val
),
247 register_size (gdbarch
, regnum
), byte_order
, val
);
252 frame_unwind_got_bytes (struct frame_info
*frame
, int regnum
, gdb_byte
*buf
)
254 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
255 struct value
*reg_val
;
257 reg_val
= value_zero (register_type (gdbarch
, regnum
), not_lval
);
258 memcpy (value_contents_raw (reg_val
), buf
, register_size (gdbarch
, regnum
));
262 /* Return a value which indicates that FRAME's saved version of REGNUM
263 has a known constant (computed) value of ADDR. Convert the
264 CORE_ADDR to a target address if necessary. */
267 frame_unwind_got_address (struct frame_info
*frame
, int regnum
,
270 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
271 struct value
*reg_val
;
273 reg_val
= value_zero (register_type (gdbarch
, regnum
), not_lval
);
274 pack_long (value_contents_writeable (reg_val
),
275 register_type (gdbarch
, regnum
), addr
);
279 /* -Wmissing-prototypes */
280 extern initialize_file_ftype _initialize_frame_unwind
;
283 _initialize_frame_unwind (void)
285 frame_unwind_data
= gdbarch_data_register_pre_init (frame_unwind_init
);