1 /* Frame unwinder for frames using the libunwind library.
3 Copyright 2003 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., 59 Temple Place - Suite 330,
22 Boston, MA 02111-1307, 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;
49 #define LIBUNWIND_SO "libunwind.so"
52 /* Required function pointers from libunwind. */
53 static int (*unw_get_reg_p) (unw_cursor_t *, unw_regnum_t, unw_word_t *);
54 static int (*unw_get_fpreg_p) (unw_cursor_t *, unw_regnum_t, unw_fpreg_t *);
55 static int (*unw_get_saveloc_p) (unw_cursor_t *, unw_regnum_t, unw_save_loc_t *);
56 static int (*unw_step_p) (unw_cursor_t *);
57 static int (*unw_init_remote_p) (unw_cursor_t *, unw_addr_space_t, void *);
58 static unw_addr_space_t (*unw_create_addr_space_p) (unw_accessors_t *, int);
59 static int (*unw_search_unwind_table_p) (unw_addr_space_t, unw_word_t, unw_dyn_info_t *,
60 unw_proc_info_t *, int, void *);
61 static unw_word_t (*unw_find_dyn_list_p) (unw_addr_space_t, unw_dyn_info_t *,
65 struct libunwind_frame_cache
72 /* We need to qualify the function names with a platform-specific prefix to match
73 the names used by the libunwind library. The UNW_OBJ macro is provided by the
74 libunwind.h header file. */
75 #define STRINGIFY2(name) #name
76 #define STRINGIFY(name) STRINGIFY2(name)
78 static char *get_reg_name = STRINGIFY(UNW_OBJ(get_reg));
79 static char *get_fpreg_name = STRINGIFY(UNW_OBJ(get_fpreg));
80 static char *get_saveloc_name = STRINGIFY(UNW_OBJ(get_save_loc));
81 static char *step_name = STRINGIFY(UNW_OBJ(step));
82 static char *init_remote_name = STRINGIFY(UNW_OBJ(init_remote));
83 static char *create_addr_space_name = STRINGIFY(UNW_OBJ(create_addr_space));
84 static char *search_unwind_table_name = STRINGIFY(UNW_OBJ(search_unwind_table));
85 static char *find_dyn_list_name = STRINGIFY(UNW_OBJ(find_dyn_list));
87 static struct libunwind_descr *
88 libunwind_descr (struct gdbarch *gdbarch)
90 return gdbarch_data (gdbarch, libunwind_descr_handle);
94 libunwind_descr_init (struct gdbarch *gdbarch)
96 struct libunwind_descr *descr = GDBARCH_OBSTACK_ZALLOC (gdbarch,
97 struct libunwind_descr);
102 libunwind_frame_set_descr (struct gdbarch *gdbarch, struct libunwind_descr *descr)
104 struct libunwind_descr *arch_descr;
106 gdb_assert (gdbarch != NULL);
108 arch_descr = gdbarch_data (gdbarch, libunwind_descr_handle);
110 if (arch_descr == NULL)
112 /* First time here. Must initialize data area. */
113 arch_descr = libunwind_descr_init (gdbarch);
114 set_gdbarch_data (gdbarch, libunwind_descr_handle, arch_descr);
117 /* Copy new descriptor info into arch descriptor. */
118 arch_descr->gdb2uw = descr->gdb2uw;
119 arch_descr->uw2gdb = descr->uw2gdb;
120 arch_descr->is_fpreg = descr->is_fpreg;
121 arch_descr->accessors = descr->accessors;
124 static struct libunwind_frame_cache *
125 libunwind_frame_cache (struct frame_info *next_frame, void **this_cache)
127 unw_accessors_t *acc;
130 unw_regnum_t uw_sp_regnum;
131 struct libunwind_frame_cache *cache;
132 struct libunwind_descr *descr;
138 /* Allocate a new cache. */
139 cache = FRAME_OBSTACK_ZALLOC (struct libunwind_frame_cache);
141 cache->func_addr = frame_func_unwind (next_frame);
143 /* Get a libunwind cursor to the previous frame. We do this by initializing
144 a cursor. Libunwind treats a new cursor as the top of stack and will get
145 the current register set via the libunwind register accessor. Now, we
146 provide the platform-specific accessors and we set up the register accessor to use
147 the frame register unwinding interfaces so that we properly get the registers for
148 the current frame rather than the top. We then use the unw_step function to
149 move the libunwind cursor back one frame. We can later use this cursor to find previous
150 registers via the unw_get_reg interface which will invoke libunwind's special logic. */
151 descr = libunwind_descr (get_frame_arch (next_frame));
152 acc = descr->accessors;
153 as = unw_create_addr_space_p (acc,
154 TARGET_BYTE_ORDER == BFD_ENDIAN_BIG
158 unw_init_remote_p (&cache->cursor, as, next_frame);
159 unw_step_p (&cache->cursor);
161 /* To get base address, get sp from previous frame. */
162 uw_sp_regnum = descr->gdb2uw (SP_REGNUM);
163 ret = unw_get_reg_p (&cache->cursor, uw_sp_regnum, &fp);
165 error ("Can't get libunwind sp register.");
167 cache->base = (CORE_ADDR)fp;
174 libunwind_find_dyn_list (unw_addr_space_t as, unw_dyn_info_t *di, void *arg)
176 return unw_find_dyn_list_p (as, di, arg);
179 static const struct frame_unwind libunwind_frame_unwind =
182 libunwind_frame_this_id,
183 libunwind_frame_prev_register
186 /* Verify if there is sufficient libunwind information for the frame to use
187 libunwind frame unwinding. */
188 const struct frame_unwind *
189 libunwind_frame_sniffer (struct frame_info *next_frame)
192 unw_accessors_t *acc;
194 struct libunwind_descr *descr;
197 /* To test for libunwind unwind support, initialize a cursor to the current frame and try to back
198 up. We use this same method when setting up the frame cache (see libunwind_frame_cache()).
199 If libunwind returns success for this operation, it means that it has found sufficient
200 libunwind unwinding information to do so. */
202 descr = libunwind_descr (get_frame_arch (next_frame));
203 acc = descr->accessors;
204 as = unw_create_addr_space_p (acc,
205 TARGET_BYTE_ORDER == BFD_ENDIAN_BIG
209 ret = unw_init_remote_p (&cursor, as, next_frame);
212 ret = unw_step_p (&cursor);
217 return &libunwind_frame_unwind;
221 libunwind_frame_this_id (struct frame_info *next_frame, void **this_cache,
222 struct frame_id *this_id)
224 struct libunwind_frame_cache *cache =
225 libunwind_frame_cache (next_frame, this_cache);
227 (*this_id) = frame_id_build (cache->base, cache->func_addr);
231 libunwind_frame_prev_register (struct frame_info *next_frame, void **this_cache,
232 int regnum, int *optimizedp,
233 enum lval_type *lvalp, CORE_ADDR *addrp,
234 int *realnump, void *valuep)
236 struct libunwind_frame_cache *cache =
237 libunwind_frame_cache (next_frame, this_cache);
245 unw_regnum_t uw_regnum;
246 struct libunwind_descr *descr;
248 /* Convert from gdb register number to libunwind register number. */
249 descr = libunwind_descr (get_frame_arch (next_frame));
250 uw_regnum = descr->gdb2uw (regnum);
252 gdb_assert (regnum >= 0);
254 if (!target_has_registers)
255 error ("No registers.");
262 memset (valuep, 0, register_size (current_gdbarch, regnum));
267 /* To get the previous register, we use the libunwind register APIs with
268 the cursor we have already pushed back to the previous frame. */
270 if (descr->is_fpreg (uw_regnum))
272 ret = unw_get_fpreg_p (&cache->cursor, uw_regnum, &fpval);
277 ret = unw_get_reg_p (&cache->cursor, uw_regnum, &intval);
284 memcpy (valuep, ptr, register_size (current_gdbarch, regnum));
286 if (unw_get_saveloc_p (&cache->cursor, uw_regnum, &sl) < 0)
296 *lvalp = lval_memory;
301 *lvalp = lval_register;
308 libunwind_frame_base_address (struct frame_info *next_frame, void **this_cache)
310 struct libunwind_frame_cache *cache =
311 libunwind_frame_cache (next_frame, this_cache);
316 /* The following is a glue routine to call the libunwind unwind table
317 search function to get unwind information for a specified ip address. */
319 libunwind_search_unwind_table (void *as, long ip, void *di,
320 void *pi, int need_unwind_info, void *args)
322 return unw_search_unwind_table_p (*(unw_addr_space_t *)as, (unw_word_t )ip,
323 di, pi, need_unwind_info, args);
327 libunwind_load (void)
331 handle = dlopen (LIBUNWIND_SO, RTLD_NOW);
335 /* Initialize pointers to the dynamic library functions we will use. */
337 unw_get_reg_p = dlsym (handle, get_reg_name);
338 if (unw_get_reg_p == NULL)
341 unw_get_fpreg_p = dlsym (handle, get_fpreg_name);
342 if (unw_get_fpreg_p == NULL)
345 unw_get_saveloc_p = dlsym (handle, get_saveloc_name);
346 if (unw_get_saveloc_p == NULL)
349 unw_step_p = dlsym (handle, step_name);
350 if (unw_step_p == NULL)
353 unw_init_remote_p = dlsym (handle, init_remote_name);
354 if (unw_init_remote_p == NULL)
357 unw_create_addr_space_p = dlsym (handle, create_addr_space_name);
358 if (unw_create_addr_space_p == NULL)
361 unw_search_unwind_table_p = dlsym (handle, search_unwind_table_name);
362 if (unw_search_unwind_table_p == NULL)
365 unw_find_dyn_list_p = dlsym (handle, find_dyn_list_name);
366 if (unw_find_dyn_list_p == NULL)
373 libunwind_is_initialized (void)
375 return libunwind_initialized;
378 /* Provide a prototype to silence -Wmissing-prototypes. */
379 void _initialize_libunwind_frame (void);
382 _initialize_libunwind_frame (void)
384 libunwind_descr_handle = register_gdbarch_data (libunwind_descr_init);
386 libunwind_initialized = libunwind_load ();