1 /* Return backtrace of current program state.
2 Copyright (C) 2008-2015 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Kazu Hirata <kazu@codesourcery.com>, 2008.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library 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 GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library. If not, see
18 <http://www.gnu.org/licenses/>. */
20 #include <libc-lock.h>
33 static _Unwind_Reason_Code (*unwind_backtrace
) (_Unwind_Trace_Fn
, void *);
34 static _Unwind_VRS_Result (*unwind_vrs_get
) (_Unwind_Context
*,
37 _Unwind_VRS_DataRepresentation
,
40 static void *libgcc_handle
;
45 libgcc_handle
= __libc_dlopen ("libgcc_s.so.1");
47 if (libgcc_handle
== NULL
)
50 unwind_backtrace
= __libc_dlsym (libgcc_handle
, "_Unwind_Backtrace");
51 unwind_vrs_get
= __libc_dlsym (libgcc_handle
, "_Unwind_VRS_Get");
52 if (unwind_vrs_get
== NULL
)
53 unwind_backtrace
= NULL
;
56 /* This function is identical to "_Unwind_GetGR", except that it uses
57 "unwind_vrs_get" instead of "_Unwind_VRS_Get". */
58 static inline _Unwind_Word
59 unwind_getgr (_Unwind_Context
*context
, int regno
)
62 unwind_vrs_get (context
, _UVRSC_CORE
, regno
, _UVRSD_UINT32
, &val
);
66 /* This macro is identical to the _Unwind_GetIP macro, except that it
67 uses "unwind_getgr" instead of "_Unwind_GetGR". */
68 # define unwind_getip(context) \
69 (unwind_getgr (context, 15) & ~(_Unwind_Word)1)
71 # define unwind_backtrace _Unwind_Backtrace
72 # define unwind_getip _Unwind_GetIP
75 static _Unwind_Reason_Code
76 backtrace_helper (struct _Unwind_Context
*ctx
, void *a
)
78 struct trace_arg
*arg
= a
;
80 /* We are first called with address in the __backtrace function.
83 arg
->array
[arg
->cnt
] = (void *) unwind_getip (ctx
);
84 if (++arg
->cnt
== arg
->size
)
85 return _URC_END_OF_STACK
;
86 return _URC_NO_REASON
;
90 __backtrace (array
, size
)
94 struct trace_arg arg
= { .array
= array
, .size
= size
, .cnt
= -1 };
100 __libc_once_define (static, once
);
102 __libc_once (once
, init
);
103 if (unwind_backtrace
== NULL
)
107 unwind_backtrace (backtrace_helper
, &arg
);
109 if (arg
.cnt
> 1 && arg
.array
[arg
.cnt
- 1] == NULL
)
111 return arg
.cnt
!= -1 ? arg
.cnt
: 0;
113 weak_alias (__backtrace
, backtrace
)
114 libc_hidden_def (__backtrace
)
118 /* Free all resources if necessary. */
119 libc_freeres_fn (free_mem
)
121 unwind_backtrace
= NULL
;
122 if (libgcc_handle
!= NULL
)
124 __libc_dlclose (libgcc_handle
);
125 libgcc_handle
= NULL
;