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 /* Use the stable ABI major version number. `libunwind-ia64.so' is a link time
77 only library, not a runtime one. */
78 #define LIBUNWIND_SO "libunwind-" STRINGIFY(UNW_TARGET) ".so.7"
81 static char *get_reg_name
= STRINGIFY(UNW_OBJ(get_reg
));
82 static char *get_fpreg_name
= STRINGIFY(UNW_OBJ(get_fpreg
));
83 static char *get_saveloc_name
= STRINGIFY(UNW_OBJ(get_save_loc
));
84 static char *is_signal_frame_name
= STRINGIFY(UNW_OBJ(is_signal_frame
));
85 static char *step_name
= STRINGIFY(UNW_OBJ(step
));
86 static char *init_remote_name
= STRINGIFY(UNW_OBJ(init_remote
));
87 static char *create_addr_space_name
= STRINGIFY(UNW_OBJ(create_addr_space
));
88 static char *search_unwind_table_name
= STRINGIFY(UNW_OBJ(search_unwind_table
));
89 static char *find_dyn_list_name
= STRINGIFY(UNW_OBJ(find_dyn_list
));
91 static struct libunwind_descr
*
92 libunwind_descr (struct gdbarch
*gdbarch
)
94 return gdbarch_data (gdbarch
, libunwind_descr_handle
);
98 libunwind_descr_init (struct gdbarch
*gdbarch
)
100 struct libunwind_descr
*descr
= GDBARCH_OBSTACK_ZALLOC (gdbarch
,
101 struct libunwind_descr
);
106 libunwind_frame_set_descr (struct gdbarch
*gdbarch
, struct libunwind_descr
*descr
)
108 struct libunwind_descr
*arch_descr
;
110 gdb_assert (gdbarch
!= NULL
);
112 arch_descr
= gdbarch_data (gdbarch
, libunwind_descr_handle
);
114 if (arch_descr
== NULL
)
116 /* First time here. Must initialize data area. */
117 arch_descr
= libunwind_descr_init (gdbarch
);
118 deprecated_set_gdbarch_data (gdbarch
, libunwind_descr_handle
, arch_descr
);
121 /* Copy new descriptor info into arch descriptor. */
122 arch_descr
->gdb2uw
= descr
->gdb2uw
;
123 arch_descr
->uw2gdb
= descr
->uw2gdb
;
124 arch_descr
->is_fpreg
= descr
->is_fpreg
;
125 arch_descr
->accessors
= descr
->accessors
;
126 arch_descr
->special_accessors
= descr
->special_accessors
;
129 static struct libunwind_frame_cache
*
130 libunwind_frame_cache (struct frame_info
*next_frame
, void **this_cache
)
132 unw_accessors_t
*acc
;
135 unw_regnum_t uw_sp_regnum
;
136 struct libunwind_frame_cache
*cache
;
137 struct libunwind_descr
*descr
;
143 /* Allocate a new cache. */
144 cache
= FRAME_OBSTACK_ZALLOC (struct libunwind_frame_cache
);
146 /* We can assume we are unwinding a normal frame. Even if this is
147 for a signal trampoline, ia64 signal "trampolines" use a normal
148 subroutine call to start the signal handler. */
149 cache
->func_addr
= frame_func_unwind (next_frame
, NORMAL_FRAME
);
150 if (cache
->func_addr
== 0
151 && frame_relative_level (next_frame
) > 0
152 && get_frame_type (next_frame
) != SIGTRAMP_FRAME
)
155 /* Get a libunwind cursor to the previous frame. We do this by initializing
156 a cursor. Libunwind treats a new cursor as the top of stack and will get
157 the current register set via the libunwind register accessor. Now, we
158 provide the platform-specific accessors and we set up the register accessor to use
159 the frame register unwinding interfaces so that we properly get the registers for
160 the current frame rather than the top. We then use the unw_step function to
161 move the libunwind cursor back one frame. We can later use this cursor to find previous
162 registers via the unw_get_reg interface which will invoke libunwind's special logic. */
163 descr
= libunwind_descr (get_frame_arch (next_frame
));
164 acc
= descr
->accessors
;
165 as
= unw_create_addr_space_p (acc
,
166 gdbarch_byte_order (current_gdbarch
)
171 unw_init_remote_p (&cache
->cursor
, as
, next_frame
);
172 if (unw_step_p (&cache
->cursor
) < 0)
175 /* To get base address, get sp from previous frame. */
176 uw_sp_regnum
= descr
->gdb2uw (SP_REGNUM
);
177 ret
= unw_get_reg_p (&cache
->cursor
, uw_sp_regnum
, &fp
);
179 error (_("Can't get libunwind sp register."));
181 cache
->base
= (CORE_ADDR
)fp
;
188 libunwind_find_dyn_list (unw_addr_space_t as
, unw_dyn_info_t
*di
, void *arg
)
190 return unw_find_dyn_list_p (as
, di
, arg
);
193 static const struct frame_unwind libunwind_frame_unwind
=
196 libunwind_frame_this_id
,
197 libunwind_frame_prev_register
200 /* Verify if there is sufficient libunwind information for the frame to use
201 libunwind frame unwinding. */
202 const struct frame_unwind
*
203 libunwind_frame_sniffer (struct frame_info
*next_frame
)
206 unw_accessors_t
*acc
;
208 struct libunwind_descr
*descr
;
211 /* To test for libunwind unwind support, initialize a cursor to the current frame and try to back
212 up. We use this same method when setting up the frame cache (see libunwind_frame_cache()).
213 If libunwind returns success for this operation, it means that it has found sufficient
214 libunwind unwinding information to do so. */
216 descr
= libunwind_descr (get_frame_arch (next_frame
));
217 acc
= descr
->accessors
;
218 as
= unw_create_addr_space_p (acc
,
219 gdbarch_byte_order (current_gdbarch
)
224 ret
= unw_init_remote_p (&cursor
, as
, next_frame
);
230 /* Check to see if we have libunwind info by checking if we are in a
231 signal frame. If it doesn't return an error, we have libunwind info
232 and can use libunwind. */
233 ret
= unw_is_signal_frame_p (&cursor
);
238 return &libunwind_frame_unwind
;
242 libunwind_frame_this_id (struct frame_info
*next_frame
, void **this_cache
,
243 struct frame_id
*this_id
)
245 struct libunwind_frame_cache
*cache
=
246 libunwind_frame_cache (next_frame
, this_cache
);
249 (*this_id
) = frame_id_build (cache
->base
, cache
->func_addr
);
251 (*this_id
) = null_frame_id
;
255 libunwind_frame_prev_register (struct frame_info
*next_frame
, void **this_cache
,
256 int regnum
, int *optimizedp
,
257 enum lval_type
*lvalp
, CORE_ADDR
*addrp
,
258 int *realnump
, gdb_byte
*valuep
)
260 struct libunwind_frame_cache
*cache
=
261 libunwind_frame_cache (next_frame
, this_cache
);
269 unw_regnum_t uw_regnum
;
270 struct libunwind_descr
*descr
;
275 /* Convert from gdb register number to libunwind register number. */
276 descr
= libunwind_descr (get_frame_arch (next_frame
));
277 uw_regnum
= descr
->gdb2uw (regnum
);
279 gdb_assert (regnum
>= 0);
281 if (!target_has_registers
)
282 error (_("No registers."));
290 memset (valuep
, 0, register_size (current_gdbarch
, regnum
));
295 /* To get the previous register, we use the libunwind register APIs with
296 the cursor we have already pushed back to the previous frame. */
298 if (descr
->is_fpreg (uw_regnum
))
300 ret
= unw_get_fpreg_p (&cache
->cursor
, uw_regnum
, &fpval
);
305 ret
= unw_get_reg_p (&cache
->cursor
, uw_regnum
, &intval
);
313 memcpy (valuep
, ptr
, register_size (current_gdbarch
, regnum
));
315 if (unw_get_saveloc_p (&cache
->cursor
, uw_regnum
, &sl
) < 0)
325 *lvalp
= lval_memory
;
330 *lvalp
= lval_register
;
337 libunwind_frame_base_address (struct frame_info
*next_frame
, void **this_cache
)
339 struct libunwind_frame_cache
*cache
=
340 libunwind_frame_cache (next_frame
, this_cache
);
343 return (CORE_ADDR
)NULL
;
347 /* The following is a glue routine to call the libunwind unwind table
348 search function to get unwind information for a specified ip address. */
350 libunwind_search_unwind_table (void *as
, long ip
, void *di
,
351 void *pi
, int need_unwind_info
, void *args
)
353 return unw_search_unwind_table_p (*(unw_addr_space_t
*)as
, (unw_word_t
)ip
,
354 di
, pi
, need_unwind_info
, args
);
357 /* Verify if we are in a sigtramp frame and we can use libunwind to unwind. */
358 const struct frame_unwind
*
359 libunwind_sigtramp_frame_sniffer (struct frame_info
*next_frame
)
362 unw_accessors_t
*acc
;
364 struct libunwind_descr
*descr
;
367 /* To test for libunwind unwind support, initialize a cursor to the
368 current frame and try to back up. We use this same method when
369 setting up the frame cache (see libunwind_frame_cache()). If
370 libunwind returns success for this operation, it means that it
371 has found sufficient libunwind unwinding information to do
374 descr
= libunwind_descr (get_frame_arch (next_frame
));
375 acc
= descr
->accessors
;
376 as
= unw_create_addr_space_p (acc
,
377 gdbarch_byte_order (current_gdbarch
)
382 ret
= unw_init_remote_p (&cursor
, as
, next_frame
);
387 /* Check to see if we are in a signal frame. */
388 ret
= unw_is_signal_frame_p (&cursor
);
390 return &libunwind_frame_unwind
;
395 /* The following routine is for accessing special registers of the top frame.
396 A special set of accessors must be given that work without frame info.
397 This is used by ia64 to access the rse registers r32-r127. While they
398 are usually located at BOF, this is not always true and only the libunwind
399 info can decipher where they actually are. */
401 libunwind_get_reg_special (struct gdbarch
*gdbarch
, struct regcache
*regcache
,
402 int regnum
, void *buf
)
405 unw_accessors_t
*acc
;
407 struct libunwind_descr
*descr
;
409 unw_regnum_t uw_regnum
;
415 descr
= libunwind_descr (gdbarch
);
416 acc
= descr
->special_accessors
;
417 as
= unw_create_addr_space_p (acc
,
418 gdbarch_byte_order (current_gdbarch
)
423 ret
= unw_init_remote_p (&cursor
, as
, regcache
);
427 uw_regnum
= descr
->gdb2uw (regnum
);
429 if (descr
->is_fpreg (uw_regnum
))
431 ret
= unw_get_fpreg_p (&cursor
, uw_regnum
, &fpval
);
436 ret
= unw_get_reg_p (&cursor
, uw_regnum
, &intval
);
444 memcpy (buf
, ptr
, register_size (current_gdbarch
, regnum
));
450 libunwind_load (void)
454 handle
= dlopen (LIBUNWIND_SO
, RTLD_NOW
);
458 /* Initialize pointers to the dynamic library functions we will use. */
460 unw_get_reg_p
= dlsym (handle
, get_reg_name
);
461 if (unw_get_reg_p
== NULL
)
464 unw_get_fpreg_p
= dlsym (handle
, get_fpreg_name
);
465 if (unw_get_fpreg_p
== NULL
)
468 unw_get_saveloc_p
= dlsym (handle
, get_saveloc_name
);
469 if (unw_get_saveloc_p
== NULL
)
472 unw_is_signal_frame_p
= dlsym (handle
, is_signal_frame_name
);
473 if (unw_is_signal_frame_p
== NULL
)
476 unw_step_p
= dlsym (handle
, step_name
);
477 if (unw_step_p
== NULL
)
480 unw_init_remote_p
= dlsym (handle
, init_remote_name
);
481 if (unw_init_remote_p
== NULL
)
484 unw_create_addr_space_p
= dlsym (handle
, create_addr_space_name
);
485 if (unw_create_addr_space_p
== NULL
)
488 unw_search_unwind_table_p
= dlsym (handle
, search_unwind_table_name
);
489 if (unw_search_unwind_table_p
== NULL
)
492 unw_find_dyn_list_p
= dlsym (handle
, find_dyn_list_name
);
493 if (unw_find_dyn_list_p
== NULL
)
500 libunwind_is_initialized (void)
502 return libunwind_initialized
;
505 /* Provide a prototype to silence -Wmissing-prototypes. */
506 void _initialize_libunwind_frame (void);
509 _initialize_libunwind_frame (void)
511 libunwind_descr_handle
= gdbarch_data_register_post_init (libunwind_descr_init
);
513 libunwind_initialized
= libunwind_load ();