svn merge -r102224:107263 svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-3_4-branch
[official-gcc.git] / gcc / unwind-dw2-fde-glibc.c
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1 /* Copyright (C) 2001, 2002, 2003 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 2, 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 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 /* As a special exception, if you link this library with other files,
22 some of which are compiled with GCC, to produce an executable,
23 this library does not by itself cause the resulting executable
24 to be covered by the GNU General Public License.
25 This exception does not however invalidate any other reasons why
26 the executable file might be covered by the GNU General Public License. */
28 /* Locate the FDE entry for a given address, using PT_GNU_EH_FRAME ELF
29 segment and dl_iterate_phdr to avoid register/deregister calls at
30 DSO load/unload. */
32 #ifndef _GNU_SOURCE
33 #define _GNU_SOURCE 1
34 #endif
36 #include "auto-host.h" /* For HAVE_LD_EH_FRAME_HDR. */
37 #include "tconfig.h"
38 #include "tsystem.h"
39 #ifndef inhibit_libc
40 #include <link.h>
41 #endif
42 #include "coretypes.h"
43 #include "tm.h"
44 #include "dwarf2.h"
45 #include "unwind.h"
46 #define NO_BASE_OF_ENCODED_VALUE
47 #include "unwind-pe.h"
48 #include "unwind-dw2-fde.h"
49 #include "unwind-compat.h"
50 #include "gthr.h"
52 #if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
53 && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2) \
54 || (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && defined(DT_CONFIG)))
56 static const fde * _Unwind_Find_registered_FDE (void *pc, struct dwarf_eh_bases *bases);
58 #define _Unwind_Find_FDE _Unwind_Find_registered_FDE
59 #include "unwind-dw2-fde.c"
60 #undef _Unwind_Find_FDE
62 #ifndef PT_GNU_EH_FRAME
63 #define PT_GNU_EH_FRAME (PT_LOOS + 0x474e550)
64 #endif
66 struct unw_eh_callback_data
68 _Unwind_Ptr pc;
69 void *tbase;
70 void *dbase;
71 void *func;
72 const fde *ret;
75 struct unw_eh_frame_hdr
77 unsigned char version;
78 unsigned char eh_frame_ptr_enc;
79 unsigned char fde_count_enc;
80 unsigned char table_enc;
83 /* Like base_of_encoded_value, but take the base from a struct
84 unw_eh_callback_data instead of an _Unwind_Context. */
86 static _Unwind_Ptr
87 base_from_cb_data (unsigned char encoding, struct unw_eh_callback_data *data)
89 if (encoding == DW_EH_PE_omit)
90 return 0;
92 switch (encoding & 0x70)
94 case DW_EH_PE_absptr:
95 case DW_EH_PE_pcrel:
96 case DW_EH_PE_aligned:
97 return 0;
99 case DW_EH_PE_textrel:
100 return (_Unwind_Ptr) data->tbase;
101 case DW_EH_PE_datarel:
102 return (_Unwind_Ptr) data->dbase;
104 abort ();
107 static int
108 _Unwind_IteratePhdrCallback (struct dl_phdr_info *info, size_t size, void *ptr)
110 struct unw_eh_callback_data *data = (struct unw_eh_callback_data *) ptr;
111 const ElfW(Phdr) *phdr, *p_eh_frame_hdr, *p_dynamic;
112 long n, match;
113 _Unwind_Ptr load_base;
114 const unsigned char *p;
115 const struct unw_eh_frame_hdr *hdr;
116 _Unwind_Ptr eh_frame;
117 struct object ob;
119 /* Make sure struct dl_phdr_info is at least as big as we need. */
120 if (size < offsetof (struct dl_phdr_info, dlpi_phnum)
121 + sizeof (info->dlpi_phnum))
122 return -1;
124 match = 0;
125 phdr = info->dlpi_phdr;
126 load_base = info->dlpi_addr;
127 p_eh_frame_hdr = NULL;
128 p_dynamic = NULL;
130 /* See if PC falls into one of the loaded segments. Find the eh_frame
131 segment at the same time. */
132 for (n = info->dlpi_phnum; --n >= 0; phdr++)
134 if (phdr->p_type == PT_LOAD)
136 _Unwind_Ptr vaddr = phdr->p_vaddr + load_base;
137 if (data->pc >= vaddr && data->pc < vaddr + phdr->p_memsz)
138 match = 1;
140 else if (phdr->p_type == PT_GNU_EH_FRAME)
141 p_eh_frame_hdr = phdr;
142 else if (phdr->p_type == PT_DYNAMIC)
143 p_dynamic = phdr;
145 if (!match || !p_eh_frame_hdr)
146 return 0;
148 /* Read .eh_frame_hdr header. */
149 hdr = (const struct unw_eh_frame_hdr *)
150 (p_eh_frame_hdr->p_vaddr + load_base);
151 if (hdr->version != 1)
152 return 1;
154 #ifdef CRT_GET_RFIB_DATA
155 # ifdef __i386__
156 data->dbase = NULL;
157 if (p_dynamic)
159 /* For dynamically linked executables and shared libraries,
160 DT_PLTGOT is the gp value for that object. */
161 ElfW(Dyn) *dyn = (ElfW(Dyn) *) (p_dynamic->p_vaddr + load_base);
162 for (; dyn->d_tag != DT_NULL ; dyn++)
163 if (dyn->d_tag == DT_PLTGOT)
165 /* On IA-32, _DYNAMIC is writable and GLIBC has relocated it. */
166 data->dbase = (void *) dyn->d_un.d_ptr;
167 break;
170 # else
171 # error What is DW_EH_PE_datarel base on this platform?
172 # endif
173 #endif
175 p = read_encoded_value_with_base (hdr->eh_frame_ptr_enc,
176 base_from_cb_data (hdr->eh_frame_ptr_enc,
177 data),
178 (const unsigned char *) (hdr + 1),
179 &eh_frame);
181 /* We require here specific table encoding to speed things up.
182 Also, DW_EH_PE_datarel here means using PT_GNU_EH_FRAME start
183 as base, not the processor specific DW_EH_PE_datarel. */
184 if (hdr->fde_count_enc != DW_EH_PE_omit
185 && hdr->table_enc == (DW_EH_PE_datarel | DW_EH_PE_sdata4))
187 _Unwind_Ptr fde_count;
189 p = read_encoded_value_with_base (hdr->fde_count_enc,
190 base_from_cb_data (hdr->fde_count_enc,
191 data),
192 p, &fde_count);
193 /* Shouldn't happen. */
194 if (fde_count == 0)
195 return 1;
196 if ((((_Unwind_Ptr) p) & 3) == 0)
198 struct fde_table {
199 signed initial_loc __attribute__ ((mode (SI)));
200 signed fde __attribute__ ((mode (SI)));
202 const struct fde_table *table = (const struct fde_table *) p;
203 size_t lo, hi, mid;
204 _Unwind_Ptr data_base = (_Unwind_Ptr) hdr;
205 fde *f;
206 unsigned int f_enc, f_enc_size;
207 _Unwind_Ptr range;
209 mid = fde_count - 1;
210 if (data->pc < table[0].initial_loc + data_base)
211 return 1;
212 else if (data->pc < table[mid].initial_loc + data_base)
214 lo = 0;
215 hi = mid;
217 while (lo < hi)
219 mid = (lo + hi) / 2;
220 if (data->pc < table[mid].initial_loc + data_base)
221 hi = mid;
222 else if (data->pc >= table[mid + 1].initial_loc + data_base)
223 lo = mid + 1;
224 else
225 break;
228 if (lo >= hi)
229 __gxx_abort ();
232 f = (fde *) (table[mid].fde + data_base);
233 f_enc = get_fde_encoding (f);
234 f_enc_size = size_of_encoded_value (f_enc);
235 read_encoded_value_with_base (f_enc & 0x0f, 0,
236 &f->pc_begin[f_enc_size], &range);
237 if (data->pc < table[mid].initial_loc + data_base + range)
238 data->ret = f;
239 data->func = (void *) (table[mid].initial_loc + data_base);
240 return 1;
244 /* We have no sorted search table, so need to go the slow way.
245 As soon as GLIBC will provide API so to notify that a library has been
246 removed, we could cache this (and thus use search_object). */
247 ob.pc_begin = NULL;
248 ob.tbase = data->tbase;
249 ob.dbase = data->dbase;
250 ob.u.single = (fde *) eh_frame;
251 ob.s.i = 0;
252 ob.s.b.mixed_encoding = 1; /* Need to assume worst case. */
253 data->ret = linear_search_fdes (&ob, (fde *) eh_frame, (void *) data->pc);
254 if (data->ret != NULL)
256 unsigned int encoding = get_fde_encoding (data->ret);
257 read_encoded_value_with_base (encoding,
258 base_from_cb_data (encoding, data),
259 data->ret->pc_begin,
260 (_Unwind_Ptr *)&data->func);
262 return 1;
265 const fde *
266 _Unwind_Find_FDE (void *pc, struct dwarf_eh_bases *bases)
268 struct unw_eh_callback_data data;
269 const fde *ret;
271 ret = _Unwind_Find_registered_FDE (pc, bases);
272 if (ret != NULL)
273 return ret;
275 data.pc = (_Unwind_Ptr) pc;
276 data.tbase = NULL;
277 data.dbase = NULL;
278 data.func = NULL;
279 data.ret = NULL;
281 if (dl_iterate_phdr (_Unwind_IteratePhdrCallback, &data) < 0)
282 return NULL;
284 if (data.ret)
286 bases->tbase = data.tbase;
287 bases->dbase = data.dbase;
288 bases->func = data.func;
290 return data.ret;
293 #else
294 /* Prevent multiple include of header files. */
295 #define _Unwind_Find_FDE _Unwind_Find_FDE
296 #include "unwind-dw2-fde.c"
297 #endif
299 #if defined (USE_GAS_SYMVER) && defined (SHARED) && defined (USE_LIBUNWIND_EXCEPTIONS)
300 alias (_Unwind_Find_FDE);
301 #endif