1 /* Copyright (C) 2001 Free Software Foundation, Inc.
2 Contributed by Jakub Jelinek <jakub@redhat.com>.
4 This file is part of GNU CC.
6 GNU CC 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)
11 GNU CC 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 GNU CC; 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
32 #include "auto-host.h" /* For HAVE_LD_EH_FRAME_HDR. */
40 #define NO_BASE_OF_ENCODED_VALUE
41 #include "unwind-pe.h"
42 #include "unwind-dw2-fde.h"
45 #if defined(HAVE_LD_EH_FRAME_HDR) \
46 && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2) \
47 || (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && defined(DT_CONFIG)))
49 static fde
* _Unwind_Find_registered_FDE (void *pc
, struct dwarf_eh_bases
*bases
);
51 #define _Unwind_Find_FDE _Unwind_Find_registered_FDE
52 #include "unwind-dw2-fde.c"
53 #undef _Unwind_Find_FDE
55 #ifndef PT_GNU_EH_FRAME
56 #define PT_GNU_EH_FRAME (PT_LOOS + 0x474e550)
59 struct unw_eh_callback_data
68 struct unw_eh_frame_hdr
70 unsigned char version
;
71 unsigned char eh_frame_ptr_enc
;
72 unsigned char fde_count_enc
;
73 unsigned char table_enc
;
76 /* Like base_of_encoded_value, but take the base from a struct object
77 instead of an _Unwind_Context. */
80 base_from_cb_data (unsigned char encoding
, struct unw_eh_callback_data
*data
)
82 if (encoding
== DW_EH_PE_omit
)
85 switch (encoding
& 0x70)
89 case DW_EH_PE_aligned
:
92 case DW_EH_PE_textrel
:
93 return (_Unwind_Ptr
) data
->tbase
;
94 case DW_EH_PE_datarel
:
95 return (_Unwind_Ptr
) data
->dbase
;
101 _Unwind_IteratePhdrCallback (struct dl_phdr_info
*info
, size_t size
, void *ptr
)
103 struct unw_eh_callback_data
*data
= (struct unw_eh_callback_data
*) ptr
;
104 const ElfW(Phdr
) *phdr
, *p_eh_frame_hdr
, *p_dynamic
;
106 _Unwind_Ptr load_base
;
107 const unsigned char *p
;
108 const struct unw_eh_frame_hdr
*hdr
;
109 _Unwind_Ptr eh_frame
;
112 /* Make sure struct dl_phdr_info is at least as big as we need. */
113 if (size
< offsetof (struct dl_phdr_info
, dlpi_phnum
)
114 + sizeof (info
->dlpi_phnum
))
118 phdr
= info
->dlpi_phdr
;
119 load_base
= info
->dlpi_addr
;
120 p_eh_frame_hdr
= NULL
;
123 /* See if PC falls into one of the loaded segments. Find the eh_frame
124 segment at the same time. */
125 for (n
= info
->dlpi_phnum
; --n
>= 0; phdr
++)
127 if (phdr
->p_type
== PT_LOAD
)
129 _Unwind_Ptr vaddr
= phdr
->p_vaddr
+ load_base
;
130 if (data
->pc
>= vaddr
&& data
->pc
< vaddr
+ phdr
->p_memsz
)
133 else if (phdr
->p_type
== PT_GNU_EH_FRAME
)
134 p_eh_frame_hdr
= phdr
;
135 else if (phdr
->p_type
== PT_DYNAMIC
)
138 if (!match
|| !p_eh_frame_hdr
)
141 /* Read .eh_frame_hdr header. */
142 hdr
= (const struct unw_eh_frame_hdr
*)
143 (p_eh_frame_hdr
->p_vaddr
+ load_base
);
144 if (hdr
->version
!= 1)
147 #ifdef CRT_GET_RFIB_DATA
152 /* For dynamicly linked executables and shared libraries,
153 DT_PLTGOT is the gp value for that object. */
154 ElfW(Dyn
) *dyn
= (ElfW(Dyn
) *)(p_dynamic
->p_vaddr
+ load_base
);
155 for (; dyn
->d_tag
!= DT_NULL
; dyn
++)
156 if (dyn
->d_tag
== DT_PLTGOT
)
158 /* On IA-32, _DYNAMIC is writable and GLIBC has relocated it. */
159 data
->dbase
= (void *) dyn
->d_un
.d_ptr
;
164 # error What is DW_EH_PE_datarel base on this platform?
167 #ifdef CRT_GET_RFIB_TEXT
168 # error What is DW_EH_PE_textrel base on this platform?
171 p
= read_encoded_value_with_base (hdr
->eh_frame_ptr_enc
,
172 base_from_cb_data (hdr
->eh_frame_ptr_enc
,
174 (const unsigned char *) (hdr
+ 1),
177 /* We require here specific table encoding to speed things up.
178 Also, DW_EH_PE_datarel here means using PT_GNU_EH_FRAME start
179 as base, not the processor specific DW_EH_PE_datarel. */
180 if (hdr
->fde_count_enc
!= DW_EH_PE_omit
181 && hdr
->table_enc
== (DW_EH_PE_datarel
| DW_EH_PE_sdata4
))
183 _Unwind_Ptr fde_count
;
185 p
= read_encoded_value_with_base (hdr
->fde_count_enc
,
186 base_from_cb_data (hdr
->fde_count_enc
,
189 /* Shouldn't happen. */
192 if ((((_Unwind_Ptr
) p
) & 3) == 0)
195 signed initial_loc
__attribute__ ((mode (SI
)));
196 signed fde
__attribute__ ((mode (SI
)));
198 const struct fde_table
*table
= (const struct fde_table
*) p
;
200 _Unwind_Ptr data_base
= (_Unwind_Ptr
) hdr
;
202 unsigned int f_enc
, f_enc_size
;
206 if (data
->pc
< table
[0].initial_loc
+ data_base
)
208 else if (data
->pc
< table
[mid
].initial_loc
+ data_base
)
216 if (data
->pc
< table
[mid
].initial_loc
+ data_base
)
218 else if (data
->pc
>= table
[mid
+ 1].initial_loc
+ data_base
)
228 f
= (fde
*) (table
[mid
].fde
+ data_base
);
229 f_enc
= get_fde_encoding (f
);
230 f_enc_size
= size_of_encoded_value (f_enc
);
231 read_encoded_value_with_base (f_enc
& 0x0f, 0,
232 &f
->pc_begin
[f_enc_size
], &range
);
233 if (data
->pc
< table
[mid
].initial_loc
+ data_base
+ range
)
235 data
->func
= (void *) (table
[mid
].initial_loc
+ data_base
);
240 /* We have no sorted search table, so need to go the slow way.
241 As soon as GLIBC will provide API so to notify that a library has been
242 removed, we could cache this (and thus use search_object). */
244 ob
.tbase
= data
->tbase
;
245 ob
.dbase
= data
->dbase
;
246 ob
.u
.single
= (fde
*) eh_frame
;
248 ob
.s
.b
.mixed_encoding
= 1; /* Need to assume worst case. */
249 data
->ret
= linear_search_fdes (&ob
, (fde
*) eh_frame
, (void *) data
->pc
);
250 if (data
->ret
!= NULL
)
252 unsigned int encoding
= get_fde_encoding (data
->ret
);
253 read_encoded_value_with_base (encoding
,
254 base_from_cb_data (encoding
, data
),
256 (_Unwind_Ptr
*)&data
->func
);
262 _Unwind_Find_FDE (void *pc
, struct dwarf_eh_bases
*bases
)
264 struct unw_eh_callback_data data
;
267 ret
= _Unwind_Find_registered_FDE (pc
, bases
);
271 data
.pc
= (_Unwind_Ptr
) pc
;
277 if (dl_iterate_phdr (_Unwind_IteratePhdrCallback
, &data
) < 0)
282 bases
->tbase
= data
.tbase
;
283 bases
->dbase
= data
.dbase
;
284 bases
->func
= data
.func
;
290 #include "unwind-dw2-fde.c"