1 /* Definitions for frame unwinder, for GDB, the GNU debugger.
3 Copyright (C) 2003-2013 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 "exceptions.h"
28 #include "gdb_assert.h"
29 #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
= 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
= gdbarch_data (gdbarch
, frame_unwind_data
);
83 struct frame_unwind_table_entry
**ip
;
85 /* Find the end of the list and insert the new entry there. */
86 for (ip
= table
->osabi_head
; (*ip
) != NULL
; ip
= &(*ip
)->next
);
87 (*ip
) = GDBARCH_OBSTACK_ZALLOC (gdbarch
, struct frame_unwind_table_entry
);
88 (*ip
)->unwinder
= unwinder
;
91 /* Iterate through sniffers for THIS_FRAME frame until one returns with an
92 unwinder implementation. THIS_FRAME->UNWIND must be NULL, it will get set
93 by this function. Possibly initialize THIS_CACHE. */
96 frame_unwind_find_by_frame (struct frame_info
*this_frame
, void **this_cache
)
98 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
99 struct frame_unwind_table
*table
= gdbarch_data (gdbarch
, frame_unwind_data
);
100 struct frame_unwind_table_entry
*entry
;
102 for (entry
= table
->list
; entry
!= NULL
; entry
= entry
->next
)
104 struct cleanup
*old_cleanup
;
105 volatile struct gdb_exception ex
;
108 old_cleanup
= frame_prepare_for_sniffer (this_frame
, entry
->unwinder
);
110 TRY_CATCH (ex
, RETURN_MASK_ERROR
)
112 res
= entry
->unwinder
->sniffer (entry
->unwinder
, this_frame
,
115 if (ex
.reason
< 0 && ex
.error
== NOT_AVAILABLE_ERROR
)
117 /* This usually means that not even the PC is available,
118 thus most unwinders aren't able to determine if they're
119 the best fit. Keep trying. Fallback prologue unwinders
120 should always accept the frame. */
122 else if (ex
.reason
< 0)
123 throw_exception (ex
);
126 discard_cleanups (old_cleanup
);
130 do_cleanups (old_cleanup
);
132 internal_error (__FILE__
, __LINE__
, _("frame_unwind_find_by_frame failed"));
135 /* A default frame sniffer which always accepts the frame. Used by
136 fallback prologue unwinders. */
139 default_frame_sniffer (const struct frame_unwind
*self
,
140 struct frame_info
*this_frame
,
141 void **this_prologue_cache
)
146 /* The default frame unwinder stop_reason callback. */
148 enum unwind_stop_reason
149 default_frame_unwind_stop_reason (struct frame_info
*this_frame
,
152 struct frame_id this_id
= get_frame_id (this_frame
);
154 if (frame_id_eq (this_id
, outer_frame_id
))
155 return UNWIND_OUTERMOST
;
157 return UNWIND_NO_REASON
;
160 /* Helper functions for value-based register unwinding. These return
161 a (possibly lazy) value of the appropriate type. */
163 /* Return a value which indicates that FRAME did not save REGNUM. */
166 frame_unwind_got_optimized (struct frame_info
*frame
, int regnum
)
168 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
169 struct type
*type
= register_type (gdbarch
, regnum
);
172 /* Return an lval_register value, so that we print it as
174 val
= allocate_value_lazy (type
);
175 set_value_lazy (val
, 0);
176 set_value_optimized_out (val
, 1);
177 VALUE_LVAL (val
) = lval_register
;
178 VALUE_REGNUM (val
) = regnum
;
179 VALUE_FRAME_ID (val
) = get_frame_id (frame
);
183 /* Return a value which indicates that FRAME copied REGNUM into
184 register NEW_REGNUM. */
187 frame_unwind_got_register (struct frame_info
*frame
,
188 int regnum
, int new_regnum
)
190 return value_of_register_lazy (frame
, new_regnum
);
193 /* Return a value which indicates that FRAME saved REGNUM in memory at
197 frame_unwind_got_memory (struct frame_info
*frame
, int regnum
, CORE_ADDR addr
)
199 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
200 struct value
*v
= value_at_lazy (register_type (gdbarch
, regnum
), addr
);
202 set_value_stack (v
, 1);
206 /* Return a value which indicates that FRAME's saved version of
207 REGNUM has a known constant (computed) value of VAL. */
210 frame_unwind_got_constant (struct frame_info
*frame
, int regnum
,
213 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
214 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
215 struct value
*reg_val
;
217 reg_val
= value_zero (register_type (gdbarch
, regnum
), not_lval
);
218 store_unsigned_integer (value_contents_writeable (reg_val
),
219 register_size (gdbarch
, regnum
), byte_order
, val
);
224 frame_unwind_got_bytes (struct frame_info
*frame
, int regnum
, gdb_byte
*buf
)
226 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
227 struct value
*reg_val
;
229 reg_val
= value_zero (register_type (gdbarch
, regnum
), not_lval
);
230 memcpy (value_contents_raw (reg_val
), buf
, register_size (gdbarch
, regnum
));
234 /* Return a value which indicates that FRAME's saved version of REGNUM
235 has a known constant (computed) value of ADDR. Convert the
236 CORE_ADDR to a target address if necessary. */
239 frame_unwind_got_address (struct frame_info
*frame
, int regnum
,
242 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
243 struct value
*reg_val
;
245 reg_val
= value_zero (register_type (gdbarch
, regnum
), not_lval
);
246 pack_long (value_contents_writeable (reg_val
),
247 register_type (gdbarch
, regnum
), addr
);
251 /* -Wmissing-prototypes */
252 extern initialize_file_ftype _initialize_frame_unwind
;
255 _initialize_frame_unwind (void)
257 frame_unwind_data
= gdbarch_data_register_pre_init (frame_unwind_init
);