1 /* Frame unwinder for frames using the libunwind library.
3 Copyright (C) 2003, 2004, 2006, 2007 Free Software Foundation, Inc.
5 Written by Jeff Johnston, contributed by Red Hat Inc.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 51 Franklin Street, Fifth Floor,
22 Boston, MA 02110-1301, USA. */
28 #include "frame-base.h"
29 #include "frame-unwind.h"
38 #include "gdb_assert.h"
39 #include "gdb_string.h"
41 #include "libunwind-frame.h"
43 #include "complaints.h"
45 static int libunwind_initialized
;
46 static struct gdbarch_data
*libunwind_descr_handle
;
48 /* Required function pointers from libunwind. */
49 static int (*unw_get_reg_p
) (unw_cursor_t
*, unw_regnum_t
, unw_word_t
*);
50 static int (*unw_get_fpreg_p
) (unw_cursor_t
*, unw_regnum_t
, unw_fpreg_t
*);
51 static int (*unw_get_saveloc_p
) (unw_cursor_t
*, unw_regnum_t
, unw_save_loc_t
*);
52 static int (*unw_is_signal_frame_p
) (unw_cursor_t
*);
53 static int (*unw_step_p
) (unw_cursor_t
*);
54 static int (*unw_init_remote_p
) (unw_cursor_t
*, unw_addr_space_t
, void *);
55 static unw_addr_space_t (*unw_create_addr_space_p
) (unw_accessors_t
*, int);
56 static int (*unw_search_unwind_table_p
) (unw_addr_space_t
, unw_word_t
, unw_dyn_info_t
*,
57 unw_proc_info_t
*, int, void *);
58 static unw_word_t (*unw_find_dyn_list_p
) (unw_addr_space_t
, unw_dyn_info_t
*,
62 struct libunwind_frame_cache
69 /* We need to qualify the function names with a platform-specific prefix to match
70 the names used by the libunwind library. The UNW_OBJ macro is provided by the
71 libunwind.h header file. */
72 #define STRINGIFY2(name) #name
73 #define STRINGIFY(name) STRINGIFY2(name)
76 #define LIBUNWIND_SO "libunwind-" STRINGIFY(UNW_TARGET) ".so"
79 static char *get_reg_name
= STRINGIFY(UNW_OBJ(get_reg
));
80 static char *get_fpreg_name
= STRINGIFY(UNW_OBJ(get_fpreg
));
81 static char *get_saveloc_name
= STRINGIFY(UNW_OBJ(get_save_loc
));
82 static char *is_signal_frame_name
= STRINGIFY(UNW_OBJ(is_signal_frame
));
83 static char *step_name
= STRINGIFY(UNW_OBJ(step
));
84 static char *init_remote_name
= STRINGIFY(UNW_OBJ(init_remote
));
85 static char *create_addr_space_name
= STRINGIFY(UNW_OBJ(create_addr_space
));
86 static char *search_unwind_table_name
= STRINGIFY(UNW_OBJ(search_unwind_table
));
87 static char *find_dyn_list_name
= STRINGIFY(UNW_OBJ(find_dyn_list
));
89 static struct libunwind_descr
*
90 libunwind_descr (struct gdbarch
*gdbarch
)
92 return gdbarch_data (gdbarch
, libunwind_descr_handle
);
96 libunwind_descr_init (struct gdbarch
*gdbarch
)
98 struct libunwind_descr
*descr
= GDBARCH_OBSTACK_ZALLOC (gdbarch
,
99 struct libunwind_descr
);
104 libunwind_frame_set_descr (struct gdbarch
*gdbarch
, struct libunwind_descr
*descr
)
106 struct libunwind_descr
*arch_descr
;
108 gdb_assert (gdbarch
!= NULL
);
110 arch_descr
= gdbarch_data (gdbarch
, libunwind_descr_handle
);
112 if (arch_descr
== NULL
)
114 /* First time here. Must initialize data area. */
115 arch_descr
= libunwind_descr_init (gdbarch
);
116 deprecated_set_gdbarch_data (gdbarch
, libunwind_descr_handle
, arch_descr
);
119 /* Copy new descriptor info into arch descriptor. */
120 arch_descr
->gdb2uw
= descr
->gdb2uw
;
121 arch_descr
->uw2gdb
= descr
->uw2gdb
;
122 arch_descr
->is_fpreg
= descr
->is_fpreg
;
123 arch_descr
->accessors
= descr
->accessors
;
124 arch_descr
->special_accessors
= descr
->special_accessors
;
127 static struct libunwind_frame_cache
*
128 libunwind_frame_cache (struct frame_info
*next_frame
, void **this_cache
)
130 unw_accessors_t
*acc
;
133 unw_regnum_t uw_sp_regnum
;
134 struct libunwind_frame_cache
*cache
;
135 struct libunwind_descr
*descr
;
141 /* Allocate a new cache. */
142 cache
= FRAME_OBSTACK_ZALLOC (struct libunwind_frame_cache
);
144 /* We can assume we are unwinding a normal frame. Even if this is
145 for a signal trampoline, ia64 signal "trampolines" use a normal
146 subroutine call to start the signal handler. */
147 cache
->func_addr
= frame_func_unwind (next_frame
, NORMAL_FRAME
);
148 if (cache
->func_addr
== 0
149 && frame_relative_level (next_frame
) > 0
150 && get_frame_type (next_frame
) != SIGTRAMP_FRAME
)
153 /* Get a libunwind cursor to the previous frame. We do this by initializing
154 a cursor. Libunwind treats a new cursor as the top of stack and will get
155 the current register set via the libunwind register accessor. Now, we
156 provide the platform-specific accessors and we set up the register accessor to use
157 the frame register unwinding interfaces so that we properly get the registers for
158 the current frame rather than the top. We then use the unw_step function to
159 move the libunwind cursor back one frame. We can later use this cursor to find previous
160 registers via the unw_get_reg interface which will invoke libunwind's special logic. */
161 descr
= libunwind_descr (get_frame_arch (next_frame
));
162 acc
= descr
->accessors
;
163 as
= unw_create_addr_space_p (acc
,
164 TARGET_BYTE_ORDER
== BFD_ENDIAN_BIG
168 unw_init_remote_p (&cache
->cursor
, as
, next_frame
);
169 if (unw_step_p (&cache
->cursor
) < 0)
172 /* To get base address, get sp from previous frame. */
173 uw_sp_regnum
= descr
->gdb2uw (SP_REGNUM
);
174 ret
= unw_get_reg_p (&cache
->cursor
, uw_sp_regnum
, &fp
);
176 error (_("Can't get libunwind sp register."));
178 cache
->base
= (CORE_ADDR
)fp
;
185 libunwind_find_dyn_list (unw_addr_space_t as
, unw_dyn_info_t
*di
, void *arg
)
187 return unw_find_dyn_list_p (as
, di
, arg
);
190 static const struct frame_unwind libunwind_frame_unwind
=
193 libunwind_frame_this_id
,
194 libunwind_frame_prev_register
197 /* Verify if there is sufficient libunwind information for the frame to use
198 libunwind frame unwinding. */
199 const struct frame_unwind
*
200 libunwind_frame_sniffer (struct frame_info
*next_frame
)
203 unw_accessors_t
*acc
;
205 struct libunwind_descr
*descr
;
208 /* To test for libunwind unwind support, initialize a cursor to the current frame and try to back
209 up. We use this same method when setting up the frame cache (see libunwind_frame_cache()).
210 If libunwind returns success for this operation, it means that it has found sufficient
211 libunwind unwinding information to do so. */
213 descr
= libunwind_descr (get_frame_arch (next_frame
));
214 acc
= descr
->accessors
;
215 as
= unw_create_addr_space_p (acc
,
216 TARGET_BYTE_ORDER
== BFD_ENDIAN_BIG
220 ret
= unw_init_remote_p (&cursor
, as
, next_frame
);
226 /* Check to see if we have libunwind info by checking if we are in a
227 signal frame. If it doesn't return an error, we have libunwind info
228 and can use libunwind. */
229 ret
= unw_is_signal_frame_p (&cursor
);
234 return &libunwind_frame_unwind
;
238 libunwind_frame_this_id (struct frame_info
*next_frame
, void **this_cache
,
239 struct frame_id
*this_id
)
241 struct libunwind_frame_cache
*cache
=
242 libunwind_frame_cache (next_frame
, this_cache
);
245 (*this_id
) = frame_id_build (cache
->base
, cache
->func_addr
);
247 (*this_id
) = null_frame_id
;
251 libunwind_frame_prev_register (struct frame_info
*next_frame
, void **this_cache
,
252 int regnum
, int *optimizedp
,
253 enum lval_type
*lvalp
, CORE_ADDR
*addrp
,
254 int *realnump
, gdb_byte
*valuep
)
256 struct libunwind_frame_cache
*cache
=
257 libunwind_frame_cache (next_frame
, this_cache
);
265 unw_regnum_t uw_regnum
;
266 struct libunwind_descr
*descr
;
271 /* Convert from gdb register number to libunwind register number. */
272 descr
= libunwind_descr (get_frame_arch (next_frame
));
273 uw_regnum
= descr
->gdb2uw (regnum
);
275 gdb_assert (regnum
>= 0);
277 if (!target_has_registers
)
278 error (_("No registers."));
286 memset (valuep
, 0, register_size (current_gdbarch
, regnum
));
291 /* To get the previous register, we use the libunwind register APIs with
292 the cursor we have already pushed back to the previous frame. */
294 if (descr
->is_fpreg (uw_regnum
))
296 ret
= unw_get_fpreg_p (&cache
->cursor
, uw_regnum
, &fpval
);
301 ret
= unw_get_reg_p (&cache
->cursor
, uw_regnum
, &intval
);
309 memcpy (valuep
, ptr
, register_size (current_gdbarch
, regnum
));
311 if (unw_get_saveloc_p (&cache
->cursor
, uw_regnum
, &sl
) < 0)
321 *lvalp
= lval_memory
;
326 *lvalp
= lval_register
;
333 libunwind_frame_base_address (struct frame_info
*next_frame
, void **this_cache
)
335 struct libunwind_frame_cache
*cache
=
336 libunwind_frame_cache (next_frame
, this_cache
);
339 return (CORE_ADDR
)NULL
;
343 /* The following is a glue routine to call the libunwind unwind table
344 search function to get unwind information for a specified ip address. */
346 libunwind_search_unwind_table (void *as
, long ip
, void *di
,
347 void *pi
, int need_unwind_info
, void *args
)
349 return unw_search_unwind_table_p (*(unw_addr_space_t
*)as
, (unw_word_t
)ip
,
350 di
, pi
, need_unwind_info
, args
);
353 /* Verify if we are in a sigtramp frame and we can use libunwind to unwind. */
354 const struct frame_unwind
*
355 libunwind_sigtramp_frame_sniffer (struct frame_info
*next_frame
)
358 unw_accessors_t
*acc
;
360 struct libunwind_descr
*descr
;
363 /* To test for libunwind unwind support, initialize a cursor to the
364 current frame and try to back up. We use this same method when
365 setting up the frame cache (see libunwind_frame_cache()). If
366 libunwind returns success for this operation, it means that it
367 has found sufficient libunwind unwinding information to do
370 descr
= libunwind_descr (get_frame_arch (next_frame
));
371 acc
= descr
->accessors
;
372 as
= unw_create_addr_space_p (acc
,
373 TARGET_BYTE_ORDER
== BFD_ENDIAN_BIG
377 ret
= unw_init_remote_p (&cursor
, as
, next_frame
);
382 /* Check to see if we are in a signal frame. */
383 ret
= unw_is_signal_frame_p (&cursor
);
385 return &libunwind_frame_unwind
;
390 /* The following routine is for accessing special registers of the top frame.
391 A special set of accessors must be given that work without frame info.
392 This is used by ia64 to access the rse registers r32-r127. While they
393 are usually located at BOF, this is not always true and only the libunwind
394 info can decipher where they actually are. */
396 libunwind_get_reg_special (struct gdbarch
*gdbarch
, int regnum
, void *buf
)
399 unw_accessors_t
*acc
;
401 struct libunwind_descr
*descr
;
403 unw_regnum_t uw_regnum
;
409 descr
= libunwind_descr (gdbarch
);
410 acc
= descr
->special_accessors
;
411 as
= unw_create_addr_space_p (acc
,
412 TARGET_BYTE_ORDER
== BFD_ENDIAN_BIG
416 ret
= unw_init_remote_p (&cursor
, as
, NULL
);
420 uw_regnum
= descr
->gdb2uw (regnum
);
422 if (descr
->is_fpreg (uw_regnum
))
424 ret
= unw_get_fpreg_p (&cursor
, uw_regnum
, &fpval
);
429 ret
= unw_get_reg_p (&cursor
, uw_regnum
, &intval
);
437 memcpy (buf
, ptr
, register_size (current_gdbarch
, regnum
));
443 libunwind_load (void)
447 handle
= dlopen (LIBUNWIND_SO
, RTLD_NOW
);
451 /* Initialize pointers to the dynamic library functions we will use. */
453 unw_get_reg_p
= dlsym (handle
, get_reg_name
);
454 if (unw_get_reg_p
== NULL
)
457 unw_get_fpreg_p
= dlsym (handle
, get_fpreg_name
);
458 if (unw_get_fpreg_p
== NULL
)
461 unw_get_saveloc_p
= dlsym (handle
, get_saveloc_name
);
462 if (unw_get_saveloc_p
== NULL
)
465 unw_is_signal_frame_p
= dlsym (handle
, is_signal_frame_name
);
466 if (unw_is_signal_frame_p
== NULL
)
469 unw_step_p
= dlsym (handle
, step_name
);
470 if (unw_step_p
== NULL
)
473 unw_init_remote_p
= dlsym (handle
, init_remote_name
);
474 if (unw_init_remote_p
== NULL
)
477 unw_create_addr_space_p
= dlsym (handle
, create_addr_space_name
);
478 if (unw_create_addr_space_p
== NULL
)
481 unw_search_unwind_table_p
= dlsym (handle
, search_unwind_table_name
);
482 if (unw_search_unwind_table_p
== NULL
)
485 unw_find_dyn_list_p
= dlsym (handle
, find_dyn_list_name
);
486 if (unw_find_dyn_list_p
== NULL
)
493 libunwind_is_initialized (void)
495 return libunwind_initialized
;
498 /* Provide a prototype to silence -Wmissing-prototypes. */
499 void _initialize_libunwind_frame (void);
502 _initialize_libunwind_frame (void)
504 libunwind_descr_handle
= gdbarch_data_register_post_init (libunwind_descr_init
);
506 libunwind_initialized
= libunwind_load ();