1 /* Copyright (C) 2001, 2002, 2003, 2004, 2005, 2009 Free Software Foundation, Inc.
2 Contributed by Jakub Jelinek <jakub@redhat.com>.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
11 GCC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 Under Section 7 of GPL version 3, you are granted additional
17 permissions described in the GCC Runtime Library Exception, version
18 3.1, as published by the Free Software Foundation.
20 You should have received a copy of the GNU General Public License and
21 a copy of the GCC Runtime Library Exception along with this program;
22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 <http://www.gnu.org/licenses/>. */
25 /* Locate the FDE entry for a given address, using PT_GNU_EH_FRAME ELF
26 segment and dl_iterate_phdr to avoid register/deregister calls at
36 #include <elf.h> /* Get DT_CONFIG. */
38 #include "coretypes.h"
42 #define NO_BASE_OF_ENCODED_VALUE
43 #include "unwind-pe.h"
44 #include "unwind-dw2-fde.h"
45 #include "unwind-compat.h"
48 #if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
49 && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2) \
50 || (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && defined(DT_CONFIG)))
51 # define USE_PT_GNU_EH_FRAME
54 #if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
55 && defined(__FreeBSD__) && __FreeBSD__ >= 7
57 # define USE_PT_GNU_EH_FRAME
60 #if defined(USE_PT_GNU_EH_FRAME)
64 #ifndef __RELOC_POINTER
65 # define __RELOC_POINTER(ptr, base) ((ptr) + (base))
68 static const fde
* _Unwind_Find_registered_FDE (void *pc
, struct dwarf_eh_bases
*bases
);
70 #define _Unwind_Find_FDE _Unwind_Find_registered_FDE
71 #include "unwind-dw2-fde.c"
72 #undef _Unwind_Find_FDE
74 #ifndef PT_GNU_EH_FRAME
75 #define PT_GNU_EH_FRAME (PT_LOOS + 0x474e550)
78 struct unw_eh_callback_data
88 struct unw_eh_frame_hdr
90 unsigned char version
;
91 unsigned char eh_frame_ptr_enc
;
92 unsigned char fde_count_enc
;
93 unsigned char table_enc
;
96 #define FRAME_HDR_CACHE_SIZE 8
98 static struct frame_hdr_cache_element
102 _Unwind_Ptr load_base
;
103 const ElfW(Phdr
) *p_eh_frame_hdr
;
104 const ElfW(Phdr
) *p_dynamic
;
105 struct frame_hdr_cache_element
*link
;
106 } frame_hdr_cache
[FRAME_HDR_CACHE_SIZE
];
108 static struct frame_hdr_cache_element
*frame_hdr_cache_head
;
110 /* Like base_of_encoded_value, but take the base from a struct
111 unw_eh_callback_data instead of an _Unwind_Context. */
114 base_from_cb_data (unsigned char encoding
, struct unw_eh_callback_data
*data
)
116 if (encoding
== DW_EH_PE_omit
)
119 switch (encoding
& 0x70)
121 case DW_EH_PE_absptr
:
123 case DW_EH_PE_aligned
:
126 case DW_EH_PE_textrel
:
127 return (_Unwind_Ptr
) data
->tbase
;
128 case DW_EH_PE_datarel
:
129 return (_Unwind_Ptr
) data
->dbase
;
136 _Unwind_IteratePhdrCallback (struct dl_phdr_info
*info
, size_t size
, void *ptr
)
138 struct unw_eh_callback_data
*data
= (struct unw_eh_callback_data
*) ptr
;
139 const ElfW(Phdr
) *phdr
, *p_eh_frame_hdr
, *p_dynamic
;
142 struct elf32_fdpic_loadaddr load_base
;
144 _Unwind_Ptr load_base
;
146 const unsigned char *p
;
147 const struct unw_eh_frame_hdr
*hdr
;
148 _Unwind_Ptr eh_frame
;
150 _Unwind_Ptr pc_low
= 0, pc_high
= 0;
152 struct ext_dl_phdr_info
154 ElfW(Addr
) dlpi_addr
;
155 const char *dlpi_name
;
156 const ElfW(Phdr
) *dlpi_phdr
;
157 ElfW(Half
) dlpi_phnum
;
158 unsigned long long int dlpi_adds
;
159 unsigned long long int dlpi_subs
;
163 phdr
= info
->dlpi_phdr
;
164 load_base
= info
->dlpi_addr
;
165 p_eh_frame_hdr
= NULL
;
168 struct frame_hdr_cache_element
*prev_cache_entry
= NULL
,
169 *last_cache_entry
= NULL
;
171 if (data
->check_cache
&& size
>= sizeof (struct ext_dl_phdr_info
))
173 static unsigned long long adds
= -1ULL, subs
;
174 struct ext_dl_phdr_info
*einfo
= (struct ext_dl_phdr_info
*) info
;
176 /* We use a least recently used cache replacement policy. Also,
177 the most recently used cache entries are placed at the head
178 of the search chain. */
180 if (einfo
->dlpi_adds
== adds
&& einfo
->dlpi_subs
== subs
)
182 /* Find data->pc in shared library cache.
183 Set load_base, p_eh_frame_hdr and p_dynamic
184 plus match from the cache and goto
185 "Read .eh_frame_hdr header." below. */
187 struct frame_hdr_cache_element
*cache_entry
;
189 for (cache_entry
= frame_hdr_cache_head
;
191 cache_entry
= cache_entry
->link
)
193 if (data
->pc
>= cache_entry
->pc_low
194 && data
->pc
< cache_entry
->pc_high
)
196 load_base
= cache_entry
->load_base
;
197 p_eh_frame_hdr
= cache_entry
->p_eh_frame_hdr
;
198 p_dynamic
= cache_entry
->p_dynamic
;
200 /* And move the entry we're using to the head. */
201 if (cache_entry
!= frame_hdr_cache_head
)
203 prev_cache_entry
->link
= cache_entry
->link
;
204 cache_entry
->link
= frame_hdr_cache_head
;
205 frame_hdr_cache_head
= cache_entry
;
210 last_cache_entry
= cache_entry
;
211 /* Exit early if we found an unused entry. */
212 if ((cache_entry
->pc_low
| cache_entry
->pc_high
) == 0)
214 if (cache_entry
->link
!= NULL
)
215 prev_cache_entry
= cache_entry
;
220 adds
= einfo
->dlpi_adds
;
221 subs
= einfo
->dlpi_subs
;
222 /* Initialize the cache. Create a chain of cache entries,
223 with the final one terminated by a NULL link. */
225 for (i
= 0; i
< FRAME_HDR_CACHE_SIZE
; i
++)
227 frame_hdr_cache
[i
].pc_low
= 0;
228 frame_hdr_cache
[i
].pc_high
= 0;
229 frame_hdr_cache
[i
].link
= &frame_hdr_cache
[i
+1];
231 frame_hdr_cache
[i
-1].link
= NULL
;
232 frame_hdr_cache_head
= &frame_hdr_cache
[0];
233 data
->check_cache
= 0;
237 /* Make sure struct dl_phdr_info is at least as big as we need. */
238 if (size
< offsetof (struct dl_phdr_info
, dlpi_phnum
)
239 + sizeof (info
->dlpi_phnum
))
242 /* See if PC falls into one of the loaded segments. Find the eh_frame
243 segment at the same time. */
244 for (n
= info
->dlpi_phnum
; --n
>= 0; phdr
++)
246 if (phdr
->p_type
== PT_LOAD
)
248 _Unwind_Ptr vaddr
= (_Unwind_Ptr
)
249 __RELOC_POINTER (phdr
->p_vaddr
, load_base
);
250 if (data
->pc
>= vaddr
&& data
->pc
< vaddr
+ phdr
->p_memsz
)
254 pc_high
= vaddr
+ phdr
->p_memsz
;
257 else if (phdr
->p_type
== PT_GNU_EH_FRAME
)
258 p_eh_frame_hdr
= phdr
;
259 else if (phdr
->p_type
== PT_DYNAMIC
)
266 if (size
>= sizeof (struct ext_dl_phdr_info
))
268 /* Move the cache entry we're about to overwrite to the head of
269 the list. If either last_cache_entry or prev_cache_entry are
270 NULL, that cache entry is already at the head. */
271 if (last_cache_entry
!= NULL
&& prev_cache_entry
!= NULL
)
273 prev_cache_entry
->link
= last_cache_entry
->link
;
274 last_cache_entry
->link
= frame_hdr_cache_head
;
275 frame_hdr_cache_head
= last_cache_entry
;
278 frame_hdr_cache_head
->load_base
= load_base
;
279 frame_hdr_cache_head
->p_eh_frame_hdr
= p_eh_frame_hdr
;
280 frame_hdr_cache_head
->p_dynamic
= p_dynamic
;
281 frame_hdr_cache_head
->pc_low
= pc_low
;
282 frame_hdr_cache_head
->pc_high
= pc_high
;
290 /* Read .eh_frame_hdr header. */
291 hdr
= (const struct unw_eh_frame_hdr
*)
292 __RELOC_POINTER (p_eh_frame_hdr
->p_vaddr
, load_base
);
293 if (hdr
->version
!= 1)
296 #ifdef CRT_GET_RFIB_DATA
301 /* For dynamically linked executables and shared libraries,
302 DT_PLTGOT is the gp value for that object. */
303 ElfW(Dyn
) *dyn
= (ElfW(Dyn
) *)
304 __RELOC_POINTER (p_dynamic
->p_vaddr
, load_base
);
305 for (; dyn
->d_tag
!= DT_NULL
; dyn
++)
306 if (dyn
->d_tag
== DT_PLTGOT
)
308 /* On IA-32, _DYNAMIC is writable and GLIBC has relocated it. */
309 data
->dbase
= (void *) dyn
->d_un
.d_ptr
;
313 # elif defined __FRV_FDPIC__ && defined __linux__
314 data
->dbase
= load_base
.got_value
;
316 # error What is DW_EH_PE_datarel base on this platform?
320 p
= read_encoded_value_with_base (hdr
->eh_frame_ptr_enc
,
321 base_from_cb_data (hdr
->eh_frame_ptr_enc
,
323 (const unsigned char *) (hdr
+ 1),
326 /* We require here specific table encoding to speed things up.
327 Also, DW_EH_PE_datarel here means using PT_GNU_EH_FRAME start
328 as base, not the processor specific DW_EH_PE_datarel. */
329 if (hdr
->fde_count_enc
!= DW_EH_PE_omit
330 && hdr
->table_enc
== (DW_EH_PE_datarel
| DW_EH_PE_sdata4
))
332 _Unwind_Ptr fde_count
;
334 p
= read_encoded_value_with_base (hdr
->fde_count_enc
,
335 base_from_cb_data (hdr
->fde_count_enc
,
338 /* Shouldn't happen. */
341 if ((((_Unwind_Ptr
) p
) & 3) == 0)
344 signed initial_loc
__attribute__ ((mode (SI
)));
345 signed fde
__attribute__ ((mode (SI
)));
347 const struct fde_table
*table
= (const struct fde_table
*) p
;
349 _Unwind_Ptr data_base
= (_Unwind_Ptr
) hdr
;
351 unsigned int f_enc
, f_enc_size
;
355 if (data
->pc
< table
[0].initial_loc
+ data_base
)
357 else if (data
->pc
< table
[mid
].initial_loc
+ data_base
)
365 if (data
->pc
< table
[mid
].initial_loc
+ data_base
)
367 else if (data
->pc
>= table
[mid
+ 1].initial_loc
+ data_base
)
373 gcc_assert (lo
< hi
);
376 f
= (fde
*) (table
[mid
].fde
+ data_base
);
377 f_enc
= get_fde_encoding (f
);
378 f_enc_size
= size_of_encoded_value (f_enc
);
379 read_encoded_value_with_base (f_enc
& 0x0f, 0,
380 &f
->pc_begin
[f_enc_size
], &range
);
381 if (data
->pc
< table
[mid
].initial_loc
+ data_base
+ range
)
383 data
->func
= (void *) (table
[mid
].initial_loc
+ data_base
);
388 /* We have no sorted search table, so need to go the slow way.
389 As soon as GLIBC will provide API so to notify that a library has been
390 removed, we could cache this (and thus use search_object). */
392 ob
.tbase
= data
->tbase
;
393 ob
.dbase
= data
->dbase
;
394 ob
.u
.single
= (fde
*) eh_frame
;
396 ob
.s
.b
.mixed_encoding
= 1; /* Need to assume worst case. */
397 data
->ret
= linear_search_fdes (&ob
, (fde
*) eh_frame
, (void *) data
->pc
);
398 if (data
->ret
!= NULL
)
401 unsigned int encoding
= get_fde_encoding (data
->ret
);
403 read_encoded_value_with_base (encoding
,
404 base_from_cb_data (encoding
, data
),
405 data
->ret
->pc_begin
, &func
);
406 data
->func
= (void *) func
;
412 _Unwind_Find_FDE (void *pc
, struct dwarf_eh_bases
*bases
)
414 struct unw_eh_callback_data data
;
417 ret
= _Unwind_Find_registered_FDE (pc
, bases
);
421 data
.pc
= (_Unwind_Ptr
) pc
;
426 data
.check_cache
= 1;
428 if (dl_iterate_phdr (_Unwind_IteratePhdrCallback
, &data
) < 0)
433 bases
->tbase
= data
.tbase
;
434 bases
->dbase
= data
.dbase
;
435 bases
->func
= data
.func
;
441 /* Prevent multiple include of header files. */
442 #define _Unwind_Find_FDE _Unwind_Find_FDE
443 #include "unwind-dw2-fde.c"
446 #if defined (USE_GAS_SYMVER) && defined (SHARED) && defined (USE_LIBUNWIND_EXCEPTIONS)
447 alias (_Unwind_Find_FDE
);