1 /* Frame unwinder for frames using the libunwind library.
3 Copyright (C) 2003, 2004, 2006, 2007, 2008, 2009, 2010
4 Free Software Foundation, Inc.
6 Written by Jeff Johnston, contributed by Red Hat Inc.
8 This file is part of GDB.
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program. If not, see <http://www.gnu.org/licenses/>. */
27 #include "frame-base.h"
28 #include "frame-unwind.h"
37 #include "gdb_assert.h"
38 #include "gdb_string.h"
40 #include "libunwind-frame.h"
42 #include "complaints.h"
44 static int libunwind_initialized
;
45 static struct gdbarch_data
*libunwind_descr_handle
;
47 /* Required function pointers from libunwind. */
48 static int (*unw_get_reg_p
) (unw_cursor_t
*, unw_regnum_t
, unw_word_t
*);
49 static int (*unw_get_fpreg_p
) (unw_cursor_t
*, unw_regnum_t
, unw_fpreg_t
*);
50 static int (*unw_get_saveloc_p
) (unw_cursor_t
*, unw_regnum_t
, unw_save_loc_t
*);
51 static int (*unw_is_signal_frame_p
) (unw_cursor_t
*);
52 static int (*unw_step_p
) (unw_cursor_t
*);
53 static int (*unw_init_remote_p
) (unw_cursor_t
*, unw_addr_space_t
, void *);
54 static unw_addr_space_t (*unw_create_addr_space_p
) (unw_accessors_t
*, int);
55 static void (*unw_destroy_addr_space_p
) (unw_addr_space_t
);
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
70 /* We need to qualify the function names with a platform-specific prefix
71 to match the names used by the libunwind library. The UNW_OBJ macro is
72 provided by the libunwind.h header file. */
73 #define STRINGIFY2(name) #name
74 #define STRINGIFY(name) STRINGIFY2(name)
77 /* Use the stable ABI major version number. `libunwind-ia64.so' is a link time
78 only library, not a runtime one. */
79 #define LIBUNWIND_SO "libunwind-" STRINGIFY(UNW_TARGET) ".so.7"
82 static char *get_reg_name
= STRINGIFY(UNW_OBJ(get_reg
));
83 static char *get_fpreg_name
= STRINGIFY(UNW_OBJ(get_fpreg
));
84 static char *get_saveloc_name
= STRINGIFY(UNW_OBJ(get_save_loc
));
85 static char *is_signal_frame_name
= STRINGIFY(UNW_OBJ(is_signal_frame
));
86 static char *step_name
= STRINGIFY(UNW_OBJ(step
));
87 static char *init_remote_name
= STRINGIFY(UNW_OBJ(init_remote
));
88 static char *create_addr_space_name
= STRINGIFY(UNW_OBJ(create_addr_space
));
89 static char *destroy_addr_space_name
= STRINGIFY(UNW_OBJ(destroy_addr_space
));
90 static char *search_unwind_table_name
= STRINGIFY(UNW_OBJ(search_unwind_table
));
91 static char *find_dyn_list_name
= STRINGIFY(UNW_OBJ(find_dyn_list
));
93 static struct libunwind_descr
*
94 libunwind_descr (struct gdbarch
*gdbarch
)
96 return gdbarch_data (gdbarch
, libunwind_descr_handle
);
100 libunwind_descr_init (struct gdbarch
*gdbarch
)
102 struct libunwind_descr
*descr
= GDBARCH_OBSTACK_ZALLOC (gdbarch
,
103 struct libunwind_descr
);
109 libunwind_frame_set_descr (struct gdbarch
*gdbarch
, struct libunwind_descr
*descr
)
111 struct libunwind_descr
*arch_descr
;
113 gdb_assert (gdbarch
!= NULL
);
115 arch_descr
= gdbarch_data (gdbarch
, libunwind_descr_handle
);
117 if (arch_descr
== NULL
)
119 /* First time here. Must initialize data area. */
120 arch_descr
= libunwind_descr_init (gdbarch
);
121 deprecated_set_gdbarch_data (gdbarch
, libunwind_descr_handle
, arch_descr
);
124 /* Copy new descriptor info into arch descriptor. */
125 arch_descr
->gdb2uw
= descr
->gdb2uw
;
126 arch_descr
->uw2gdb
= descr
->uw2gdb
;
127 arch_descr
->is_fpreg
= descr
->is_fpreg
;
128 arch_descr
->accessors
= descr
->accessors
;
129 arch_descr
->special_accessors
= descr
->special_accessors
;
132 static struct libunwind_frame_cache
*
133 libunwind_frame_cache (struct frame_info
*this_frame
, void **this_cache
)
135 unw_accessors_t
*acc
;
138 unw_regnum_t uw_sp_regnum
;
139 struct libunwind_frame_cache
*cache
;
140 struct libunwind_descr
*descr
;
141 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
147 /* Allocate a new cache. */
148 cache
= FRAME_OBSTACK_ZALLOC (struct libunwind_frame_cache
);
150 /* We can assume we are unwinding a normal frame. Even if this is
151 for a signal trampoline, ia64 signal "trampolines" use a normal
152 subroutine call to start the signal handler. */
153 cache
->func_addr
= get_frame_func (this_frame
);
154 if (cache
->func_addr
== 0
155 && get_next_frame (this_frame
)
156 && get_frame_type (get_next_frame (this_frame
)) == NORMAL_FRAME
)
159 /* Get a libunwind cursor to the previous frame.
161 We do this by initializing a cursor. Libunwind treats a new cursor
162 as the top of stack and will get the current register set via the
163 libunwind register accessor. Now, we provide the platform-specific
164 accessors and we set up the register accessor to use the frame
165 register unwinding interfaces so that we properly get the registers
166 for the current frame rather than the top. We then use the unw_step
167 function to move the libunwind cursor back one frame. We can later
168 use this cursor to find previous registers via the unw_get_reg
169 interface which will invoke libunwind's special logic. */
170 descr
= libunwind_descr (gdbarch
);
171 acc
= descr
->accessors
;
172 as
= unw_create_addr_space_p (acc
,
173 gdbarch_byte_order (gdbarch
)
178 unw_init_remote_p (&cache
->cursor
, as
, this_frame
);
179 if (unw_step_p (&cache
->cursor
) < 0)
181 unw_destroy_addr_space_p (as
);
185 /* To get base address, get sp from previous frame. */
186 uw_sp_regnum
= descr
->gdb2uw (gdbarch_sp_regnum (gdbarch
));
187 ret
= unw_get_reg_p (&cache
->cursor
, uw_sp_regnum
, &fp
);
190 unw_destroy_addr_space_p (as
);
191 error (_("Can't get libunwind sp register."));
194 cache
->base
= (CORE_ADDR
)fp
;
202 libunwind_frame_dealloc_cache (struct frame_info
*self
, void *this_cache
)
204 struct libunwind_frame_cache
*cache
= this_cache
;
207 unw_destroy_addr_space_p (cache
->as
);
211 libunwind_find_dyn_list (unw_addr_space_t as
, unw_dyn_info_t
*di
, void *arg
)
213 return unw_find_dyn_list_p (as
, di
, arg
);
216 static const struct frame_unwind libunwind_frame_unwind
=
219 libunwind_frame_this_id
,
220 libunwind_frame_prev_register
,
222 libunwind_frame_sniffer
,
223 libunwind_frame_dealloc_cache
,
226 /* Verify if there is sufficient libunwind information for the frame to use
227 libunwind frame unwinding. */
229 libunwind_frame_sniffer (const struct frame_unwind
*self
,
230 struct frame_info
*this_frame
, void **this_cache
)
233 unw_accessors_t
*acc
;
235 struct libunwind_descr
*descr
;
236 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
239 /* To test for libunwind unwind support, initialize a cursor to
240 the current frame and try to back up. We use this same method
241 when setting up the frame cache (see libunwind_frame_cache()).
242 If libunwind returns success for this operation, it means that
243 it has found sufficient libunwind unwinding information to do so. */
245 descr
= libunwind_descr (gdbarch
);
246 acc
= descr
->accessors
;
247 as
= unw_create_addr_space_p (acc
,
248 gdbarch_byte_order (gdbarch
)
253 ret
= unw_init_remote_p (&cursor
, as
, this_frame
);
257 unw_destroy_addr_space_p (as
);
262 /* Check to see if we have libunwind info by checking if we are in a
263 signal frame. If it doesn't return an error, we have libunwind info
264 and can use libunwind. */
265 ret
= unw_is_signal_frame_p (&cursor
);
266 unw_destroy_addr_space_p (as
);
275 libunwind_frame_this_id (struct frame_info
*this_frame
, void **this_cache
,
276 struct frame_id
*this_id
)
278 struct libunwind_frame_cache
*cache
=
279 libunwind_frame_cache (this_frame
, this_cache
);
282 (*this_id
) = frame_id_build (cache
->base
, cache
->func_addr
);
286 libunwind_frame_prev_register (struct frame_info
*this_frame
,
287 void **this_cache
, int regnum
)
289 struct libunwind_frame_cache
*cache
=
290 libunwind_frame_cache (this_frame
, this_cache
);
291 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
299 unw_regnum_t uw_regnum
;
300 struct libunwind_descr
*descr
;
301 struct value
*val
= NULL
;
304 return frame_unwind_got_constant (this_frame
, regnum
, 0);
306 /* Convert from gdb register number to libunwind register number. */
307 descr
= libunwind_descr (get_frame_arch (this_frame
));
308 uw_regnum
= descr
->gdb2uw (regnum
);
310 gdb_assert (regnum
>= 0);
312 if (!target_has_registers
)
313 error (_("No registers."));
316 return frame_unwind_got_constant (this_frame
, regnum
, 0);
318 if (unw_get_saveloc_p (&cache
->cursor
, uw_regnum
, &sl
) < 0)
319 return frame_unwind_got_constant (this_frame
, regnum
, 0);
324 val
= frame_unwind_got_memory (this_frame
, regnum
, sl
.u
.addr
);
328 val
= frame_unwind_got_register (this_frame
, regnum
,
329 descr
->uw2gdb (sl
.u
.regnum
));
333 /* The register is not stored at a specific memory address nor
334 inside another register. So use libunwind to fetch the register
335 value for us, and create a constant value with the result. */
336 if (descr
->is_fpreg (uw_regnum
))
338 ret
= unw_get_fpreg_p (&cache
->cursor
, uw_regnum
, &fpval
);
340 return frame_unwind_got_constant (this_frame
, regnum
, 0);
341 val
= frame_unwind_got_bytes (this_frame
, regnum
,
342 (gdb_byte
*) &fpval
);
346 ret
= unw_get_reg_p (&cache
->cursor
, uw_regnum
, &intval
);
348 return frame_unwind_got_constant (this_frame
, regnum
, 0);
349 val
= frame_unwind_got_constant (this_frame
, regnum
, intval
);
359 libunwind_frame_base_address (struct frame_info
*this_frame
, void **this_cache
)
361 struct libunwind_frame_cache
*cache
=
362 libunwind_frame_cache (this_frame
, this_cache
);
365 return (CORE_ADDR
)NULL
;
369 /* The following is a glue routine to call the libunwind unwind table
370 search function to get unwind information for a specified ip address. */
372 libunwind_search_unwind_table (void *as
, long ip
, void *di
,
373 void *pi
, int need_unwind_info
, void *args
)
375 return unw_search_unwind_table_p (*(unw_addr_space_t
*)as
, (unw_word_t
)ip
,
376 di
, pi
, need_unwind_info
, args
);
379 /* Verify if we are in a sigtramp frame and we can use libunwind to unwind. */
381 libunwind_sigtramp_frame_sniffer (const struct frame_unwind
*self
,
382 struct frame_info
*this_frame
,
386 unw_accessors_t
*acc
;
388 struct libunwind_descr
*descr
;
389 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
392 /* To test for libunwind unwind support, initialize a cursor to the
393 current frame and try to back up. We use this same method when
394 setting up the frame cache (see libunwind_frame_cache()). If
395 libunwind returns success for this operation, it means that it
396 has found sufficient libunwind unwinding information to do
399 descr
= libunwind_descr (gdbarch
);
400 acc
= descr
->accessors
;
401 as
= unw_create_addr_space_p (acc
,
402 gdbarch_byte_order (gdbarch
)
407 ret
= unw_init_remote_p (&cursor
, as
, this_frame
);
411 unw_destroy_addr_space_p (as
);
415 /* Check to see if we are in a signal frame. */
416 ret
= unw_is_signal_frame_p (&cursor
);
417 unw_destroy_addr_space_p (as
);
424 /* The following routine is for accessing special registers of the top frame.
425 A special set of accessors must be given that work without frame info.
426 This is used by ia64 to access the rse registers r32-r127. While they
427 are usually located at BOF, this is not always true and only the libunwind
428 info can decipher where they actually are. */
430 libunwind_get_reg_special (struct gdbarch
*gdbarch
, struct regcache
*regcache
,
431 int regnum
, void *buf
)
434 unw_accessors_t
*acc
;
436 struct libunwind_descr
*descr
;
438 unw_regnum_t uw_regnum
;
444 descr
= libunwind_descr (gdbarch
);
445 acc
= descr
->special_accessors
;
446 as
= unw_create_addr_space_p (acc
,
447 gdbarch_byte_order (gdbarch
)
452 ret
= unw_init_remote_p (&cursor
, as
, regcache
);
455 unw_destroy_addr_space_p (as
);
459 uw_regnum
= descr
->gdb2uw (regnum
);
461 if (descr
->is_fpreg (uw_regnum
))
463 ret
= unw_get_fpreg_p (&cursor
, uw_regnum
, &fpval
);
468 ret
= unw_get_reg_p (&cursor
, uw_regnum
, &intval
);
472 unw_destroy_addr_space_p (as
);
478 memcpy (buf
, ptr
, register_size (gdbarch
, regnum
));
484 libunwind_load (void)
488 handle
= dlopen (LIBUNWIND_SO
, RTLD_NOW
);
492 /* Initialize pointers to the dynamic library functions we will use. */
494 unw_get_reg_p
= dlsym (handle
, get_reg_name
);
495 if (unw_get_reg_p
== NULL
)
498 unw_get_fpreg_p
= dlsym (handle
, get_fpreg_name
);
499 if (unw_get_fpreg_p
== NULL
)
502 unw_get_saveloc_p
= dlsym (handle
, get_saveloc_name
);
503 if (unw_get_saveloc_p
== NULL
)
506 unw_is_signal_frame_p
= dlsym (handle
, is_signal_frame_name
);
507 if (unw_is_signal_frame_p
== NULL
)
510 unw_step_p
= dlsym (handle
, step_name
);
511 if (unw_step_p
== NULL
)
514 unw_init_remote_p
= dlsym (handle
, init_remote_name
);
515 if (unw_init_remote_p
== NULL
)
518 unw_create_addr_space_p
= dlsym (handle
, create_addr_space_name
);
519 if (unw_create_addr_space_p
== NULL
)
522 unw_destroy_addr_space_p
= dlsym (handle
, destroy_addr_space_name
);
523 if (unw_destroy_addr_space_p
== NULL
)
526 unw_search_unwind_table_p
= dlsym (handle
, search_unwind_table_name
);
527 if (unw_search_unwind_table_p
== NULL
)
530 unw_find_dyn_list_p
= dlsym (handle
, find_dyn_list_name
);
531 if (unw_find_dyn_list_p
== NULL
)
538 libunwind_is_initialized (void)
540 return libunwind_initialized
;
543 /* Provide a prototype to silence -Wmissing-prototypes. */
544 void _initialize_libunwind_frame (void);
547 _initialize_libunwind_frame (void)
549 libunwind_descr_handle
= gdbarch_data_register_post_init (libunwind_descr_init
);
551 libunwind_initialized
= libunwind_load ();