2018-06-14 Richard Biener <rguenther@suse.de>
[official-gcc.git] / libgcc / unwind-dw2-fde-dip.c
blobce6a46cfd453fdf978fc1d5720d3d05eab188996
1 /* Copyright (C) 2001-2018 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)
9 any later version.
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
27 DSO load/unload. */
29 #ifndef _GNU_SOURCE
30 #define _GNU_SOURCE 1
31 #endif
33 #include "tconfig.h"
34 #include "tsystem.h"
35 #if !defined(inhibit_libc) && !defined(__OpenBSD__)
36 #include <elf.h> /* Get DT_CONFIG. */
37 #endif
38 #include "coretypes.h"
39 #include "tm.h"
40 #include "libgcc_tm.h"
41 #include "dwarf2.h"
42 #include "unwind.h"
43 #define NO_BASE_OF_ENCODED_VALUE
44 #include "unwind-pe.h"
45 #include "unwind-dw2-fde.h"
46 #include "unwind-compat.h"
47 #include "gthr.h"
49 #if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
50 && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2) \
51 || (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && defined(DT_CONFIG)))
52 # define USE_PT_GNU_EH_FRAME
53 #endif
55 #if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
56 && defined(__BIONIC__)
57 # define USE_PT_GNU_EH_FRAME
58 #endif
60 #if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
61 && defined(TARGET_DL_ITERATE_PHDR) \
62 && defined(__linux__)
63 # define USE_PT_GNU_EH_FRAME
64 #endif
66 #if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
67 && defined(TARGET_DL_ITERATE_PHDR) \
68 && (defined(__DragonFly__) || defined(__FreeBSD__))
69 # define ElfW __ElfN
70 # define USE_PT_GNU_EH_FRAME
71 #endif
73 #if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
74 && (defined(__OpenBSD__) || defined(__NetBSD__))
75 # define ElfW(type) Elf_##type
76 # define USE_PT_GNU_EH_FRAME
77 #endif
79 #if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
80 && defined(TARGET_DL_ITERATE_PHDR) \
81 && defined(__sun__) && defined(__svr4__)
82 # define USE_PT_GNU_EH_FRAME
83 #endif
85 #if defined(USE_PT_GNU_EH_FRAME)
87 #include <link.h>
89 #ifndef __RELOC_POINTER
90 # define __RELOC_POINTER(ptr, base) ((ptr) + (base))
91 #endif
93 static const fde * _Unwind_Find_registered_FDE (void *pc, struct dwarf_eh_bases *bases);
95 #define _Unwind_Find_FDE _Unwind_Find_registered_FDE
96 #include "unwind-dw2-fde.c"
97 #undef _Unwind_Find_FDE
99 #ifndef PT_GNU_EH_FRAME
100 #define PT_GNU_EH_FRAME (PT_LOOS + 0x474e550)
101 #endif
103 struct unw_eh_callback_data
105 _Unwind_Ptr pc;
106 void *tbase;
107 void *dbase;
108 void *func;
109 const fde *ret;
110 int check_cache;
113 struct unw_eh_frame_hdr
115 unsigned char version;
116 unsigned char eh_frame_ptr_enc;
117 unsigned char fde_count_enc;
118 unsigned char table_enc;
121 #define FRAME_HDR_CACHE_SIZE 8
123 static struct frame_hdr_cache_element
125 _Unwind_Ptr pc_low;
126 _Unwind_Ptr pc_high;
127 #if defined __FRV_FDPIC__ || defined __BFIN_FDPIC__
128 struct elf32_fdpic_loadaddr load_base;
129 #else
130 _Unwind_Ptr load_base;
131 #endif
132 const ElfW(Phdr) *p_eh_frame_hdr;
133 const ElfW(Phdr) *p_dynamic;
134 struct frame_hdr_cache_element *link;
135 } frame_hdr_cache[FRAME_HDR_CACHE_SIZE];
137 static struct frame_hdr_cache_element *frame_hdr_cache_head;
139 /* Like base_of_encoded_value, but take the base from a struct
140 unw_eh_callback_data instead of an _Unwind_Context. */
142 static _Unwind_Ptr
143 base_from_cb_data (unsigned char encoding, struct unw_eh_callback_data *data)
145 if (encoding == DW_EH_PE_omit)
146 return 0;
148 switch (encoding & 0x70)
150 case DW_EH_PE_absptr:
151 case DW_EH_PE_pcrel:
152 case DW_EH_PE_aligned:
153 return 0;
155 case DW_EH_PE_textrel:
156 return (_Unwind_Ptr) data->tbase;
157 case DW_EH_PE_datarel:
158 return (_Unwind_Ptr) data->dbase;
159 default:
160 gcc_unreachable ();
164 static int
165 _Unwind_IteratePhdrCallback (struct dl_phdr_info *info, size_t size, void *ptr)
167 struct unw_eh_callback_data *data = (struct unw_eh_callback_data *) ptr;
168 const ElfW(Phdr) *phdr, *p_eh_frame_hdr, *p_dynamic;
169 long n, match;
170 #if defined __FRV_FDPIC__ || defined __BFIN_FDPIC__
171 struct elf32_fdpic_loadaddr load_base;
172 #else
173 _Unwind_Ptr load_base;
174 #endif
175 const unsigned char *p;
176 const struct unw_eh_frame_hdr *hdr;
177 _Unwind_Ptr eh_frame;
178 struct object ob;
179 _Unwind_Ptr pc_low = 0, pc_high = 0;
181 struct ext_dl_phdr_info
183 ElfW(Addr) dlpi_addr;
184 const char *dlpi_name;
185 const ElfW(Phdr) *dlpi_phdr;
186 ElfW(Half) dlpi_phnum;
187 unsigned long long int dlpi_adds;
188 unsigned long long int dlpi_subs;
191 match = 0;
192 phdr = info->dlpi_phdr;
193 load_base = info->dlpi_addr;
194 p_eh_frame_hdr = NULL;
195 p_dynamic = NULL;
197 struct frame_hdr_cache_element *prev_cache_entry = NULL,
198 *last_cache_entry = NULL;
200 if (data->check_cache && size >= sizeof (struct ext_dl_phdr_info))
202 static unsigned long long adds = -1ULL, subs;
203 struct ext_dl_phdr_info *einfo = (struct ext_dl_phdr_info *) info;
205 /* We use a least recently used cache replacement policy. Also,
206 the most recently used cache entries are placed at the head
207 of the search chain. */
209 if (einfo->dlpi_adds == adds && einfo->dlpi_subs == subs)
211 /* Find data->pc in shared library cache.
212 Set load_base, p_eh_frame_hdr and p_dynamic
213 plus match from the cache and goto
214 "Read .eh_frame_hdr header." below. */
216 struct frame_hdr_cache_element *cache_entry;
218 for (cache_entry = frame_hdr_cache_head;
219 cache_entry;
220 cache_entry = cache_entry->link)
222 if (data->pc >= cache_entry->pc_low
223 && data->pc < cache_entry->pc_high)
225 load_base = cache_entry->load_base;
226 p_eh_frame_hdr = cache_entry->p_eh_frame_hdr;
227 p_dynamic = cache_entry->p_dynamic;
229 /* And move the entry we're using to the head. */
230 if (cache_entry != frame_hdr_cache_head)
232 prev_cache_entry->link = cache_entry->link;
233 cache_entry->link = frame_hdr_cache_head;
234 frame_hdr_cache_head = cache_entry;
236 goto found;
239 last_cache_entry = cache_entry;
240 /* Exit early if we found an unused entry. */
241 if ((cache_entry->pc_low | cache_entry->pc_high) == 0)
242 break;
243 if (cache_entry->link != NULL)
244 prev_cache_entry = cache_entry;
247 else
249 adds = einfo->dlpi_adds;
250 subs = einfo->dlpi_subs;
251 /* Initialize the cache. Create a chain of cache entries,
252 with the final one terminated by a NULL link. */
253 int i;
254 for (i = 0; i < FRAME_HDR_CACHE_SIZE; i++)
256 frame_hdr_cache[i].pc_low = 0;
257 frame_hdr_cache[i].pc_high = 0;
258 frame_hdr_cache[i].link = &frame_hdr_cache[i+1];
260 frame_hdr_cache[i-1].link = NULL;
261 frame_hdr_cache_head = &frame_hdr_cache[0];
262 data->check_cache = 0;
266 /* Make sure struct dl_phdr_info is at least as big as we need. */
267 if (size < offsetof (struct dl_phdr_info, dlpi_phnum)
268 + sizeof (info->dlpi_phnum))
269 return -1;
271 /* See if PC falls into one of the loaded segments. Find the eh_frame
272 segment at the same time. */
273 for (n = info->dlpi_phnum; --n >= 0; phdr++)
275 if (phdr->p_type == PT_LOAD)
277 _Unwind_Ptr vaddr = (_Unwind_Ptr)
278 __RELOC_POINTER (phdr->p_vaddr, load_base);
279 if (data->pc >= vaddr && data->pc < vaddr + phdr->p_memsz)
281 match = 1;
282 pc_low = vaddr;
283 pc_high = vaddr + phdr->p_memsz;
286 else if (phdr->p_type == PT_GNU_EH_FRAME)
287 p_eh_frame_hdr = phdr;
288 #ifdef PT_SUNW_UNWIND
289 /* Sun ld emits PT_SUNW_UNWIND .eh_frame_hdr sections instead of
290 PT_SUNW_EH_FRAME/PT_GNU_EH_FRAME, so accept them as well. */
291 else if (phdr->p_type == PT_SUNW_UNWIND)
292 p_eh_frame_hdr = phdr;
293 #endif
294 else if (phdr->p_type == PT_DYNAMIC)
295 p_dynamic = phdr;
298 if (!match)
299 return 0;
301 if (size >= sizeof (struct ext_dl_phdr_info))
303 /* Move the cache entry we're about to overwrite to the head of
304 the list. If either last_cache_entry or prev_cache_entry are
305 NULL, that cache entry is already at the head. */
306 if (last_cache_entry != NULL && prev_cache_entry != NULL)
308 prev_cache_entry->link = last_cache_entry->link;
309 last_cache_entry->link = frame_hdr_cache_head;
310 frame_hdr_cache_head = last_cache_entry;
313 frame_hdr_cache_head->load_base = load_base;
314 frame_hdr_cache_head->p_eh_frame_hdr = p_eh_frame_hdr;
315 frame_hdr_cache_head->p_dynamic = p_dynamic;
316 frame_hdr_cache_head->pc_low = pc_low;
317 frame_hdr_cache_head->pc_high = pc_high;
320 found:
322 if (!p_eh_frame_hdr)
323 return 0;
325 /* Read .eh_frame_hdr header. */
326 hdr = (const struct unw_eh_frame_hdr *)
327 __RELOC_POINTER (p_eh_frame_hdr->p_vaddr, load_base);
328 if (hdr->version != 1)
329 return 1;
331 #ifdef CRT_GET_RFIB_DATA
332 # ifdef __i386__
333 data->dbase = NULL;
334 if (p_dynamic)
336 /* For dynamically linked executables and shared libraries,
337 DT_PLTGOT is the gp value for that object. */
338 ElfW(Dyn) *dyn = (ElfW(Dyn) *)
339 __RELOC_POINTER (p_dynamic->p_vaddr, load_base);
340 for (; dyn->d_tag != DT_NULL ; dyn++)
341 if (dyn->d_tag == DT_PLTGOT)
343 data->dbase = (void *) dyn->d_un.d_ptr;
344 #if defined __linux__
345 /* On IA-32 Linux, _DYNAMIC is writable and GLIBC has
346 relocated it. */
347 #elif defined __sun__ && defined __svr4__
348 /* On Solaris 2/x86, we need to do this ourselves. */
349 data->dbase += load_base;
350 #endif
351 break;
354 # elif (defined __FRV_FDPIC__ || defined __BFIN_FDPIC__) && defined __linux__
355 data->dbase = load_base.got_value;
356 # else
357 # error What is DW_EH_PE_datarel base on this platform?
358 # endif
359 #endif
361 p = read_encoded_value_with_base (hdr->eh_frame_ptr_enc,
362 base_from_cb_data (hdr->eh_frame_ptr_enc,
363 data),
364 (const unsigned char *) (hdr + 1),
365 &eh_frame);
367 /* We require here specific table encoding to speed things up.
368 Also, DW_EH_PE_datarel here means using PT_GNU_EH_FRAME start
369 as base, not the processor specific DW_EH_PE_datarel. */
370 if (hdr->fde_count_enc != DW_EH_PE_omit
371 && hdr->table_enc == (DW_EH_PE_datarel | DW_EH_PE_sdata4))
373 _Unwind_Ptr fde_count;
375 p = read_encoded_value_with_base (hdr->fde_count_enc,
376 base_from_cb_data (hdr->fde_count_enc,
377 data),
378 p, &fde_count);
379 /* Shouldn't happen. */
380 if (fde_count == 0)
381 return 1;
382 if ((((_Unwind_Ptr) p) & 3) == 0)
384 struct fde_table {
385 signed initial_loc __attribute__ ((mode (SI)));
386 signed fde __attribute__ ((mode (SI)));
388 const struct fde_table *table = (const struct fde_table *) p;
389 size_t lo, hi, mid;
390 _Unwind_Ptr data_base = (_Unwind_Ptr) hdr;
391 fde *f;
392 unsigned int f_enc, f_enc_size;
393 _Unwind_Ptr range;
395 mid = fde_count - 1;
396 if (data->pc < table[0].initial_loc + data_base)
397 return 1;
398 else if (data->pc < table[mid].initial_loc + data_base)
400 lo = 0;
401 hi = mid;
403 while (lo < hi)
405 mid = (lo + hi) / 2;
406 if (data->pc < table[mid].initial_loc + data_base)
407 hi = mid;
408 else if (data->pc >= table[mid + 1].initial_loc + data_base)
409 lo = mid + 1;
410 else
411 break;
414 gcc_assert (lo < hi);
417 f = (fde *) (table[mid].fde + data_base);
418 f_enc = get_fde_encoding (f);
419 f_enc_size = size_of_encoded_value (f_enc);
420 read_encoded_value_with_base (f_enc & 0x0f, 0,
421 &f->pc_begin[f_enc_size], &range);
422 if (data->pc < table[mid].initial_loc + data_base + range)
423 data->ret = f;
424 data->func = (void *) (table[mid].initial_loc + data_base);
425 return 1;
429 /* We have no sorted search table, so need to go the slow way.
430 As soon as GLIBC will provide API so to notify that a library has been
431 removed, we could cache this (and thus use search_object). */
432 ob.pc_begin = NULL;
433 ob.tbase = data->tbase;
434 ob.dbase = data->dbase;
435 ob.u.single = (fde *) eh_frame;
436 ob.s.i = 0;
437 ob.s.b.mixed_encoding = 1; /* Need to assume worst case. */
438 data->ret = linear_search_fdes (&ob, (fde *) eh_frame, (void *) data->pc);
439 if (data->ret != NULL)
441 _Unwind_Ptr func;
442 unsigned int encoding = get_fde_encoding (data->ret);
444 read_encoded_value_with_base (encoding,
445 base_from_cb_data (encoding, data),
446 data->ret->pc_begin, &func);
447 data->func = (void *) func;
449 return 1;
452 const fde *
453 _Unwind_Find_FDE (void *pc, struct dwarf_eh_bases *bases)
455 struct unw_eh_callback_data data;
456 const fde *ret;
458 ret = _Unwind_Find_registered_FDE (pc, bases);
459 if (ret != NULL)
460 return ret;
462 data.pc = (_Unwind_Ptr) pc;
463 data.tbase = NULL;
464 data.dbase = NULL;
465 data.func = NULL;
466 data.ret = NULL;
467 data.check_cache = 1;
469 if (dl_iterate_phdr (_Unwind_IteratePhdrCallback, &data) < 0)
470 return NULL;
472 if (data.ret)
474 bases->tbase = data.tbase;
475 bases->dbase = data.dbase;
476 bases->func = data.func;
478 return data.ret;
481 #else
482 /* Prevent multiple include of header files. */
483 #define _Unwind_Find_FDE _Unwind_Find_FDE
484 #include "unwind-dw2-fde.c"
485 #endif
487 #if defined (USE_GAS_SYMVER) && defined (SHARED) && defined (USE_LIBUNWIND_EXCEPTIONS)
488 alias (_Unwind_Find_FDE);
489 #endif