1 /****************************************************************************
2 * *
3 * GNAT RUN-TIME COMPONENTS *
4 * *
5 * T R A C E B A C K - G C C t a b l e s *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 2004-2012, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 3, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. *
17 * *
18 * As a special exception under Section 7 of GPL version 3, you are granted *
19 * additional permissions described in the GCC Runtime Library Exception, *
20 * version 3.1, as published by the Free Software Foundation. *
21 * *
22 * You should have received a copy of the GNU General Public License and *
23 * a copy of the GCC Runtime Library Exception along with this program; *
24 * see the files COPYING3 and COPYING.RUNTIME respectively. If not, see *
25 * <http://www.gnu.org/licenses/>. *
26 * *
27 * GNAT was originally developed by the GNAT team at New York University. *
28 * Extensive contributions were provided by Ada Core Technologies Inc. *
29 * *
30 ****************************************************************************/
31
32 /* This is an implementation of the __gnat_backtrace routine using the
33 underlying GCC unwinding support associated with the exception handling
34 infrastructure. This will only work for ZCX based applications. */
35
36 #include <unwind.h>
37
38 /* The implementation boils down to a call to _Unwind_Backtrace with a
39 tailored callback and carried-on data structure to keep track of the
40 input parameters we got as well as of the basic processing state. */
41
42 /******************
43 * trace_callback *
44 ******************/
45
46 #if !defined (__USING_SJLJ_EXCEPTIONS__)
47
48 typedef struct {
49 void ** traceback;
50 int max_len;
51 void * exclude_min;
52 void * exclude_max;
53 int n_frames_to_skip;
54 int n_frames_skipped;
55 int n_entries_filled;
56 } uw_data_t;
57
58 #if defined (__ia64__) && defined (__hpux__)
59 #include <uwx.h>
60 #endif
61
62 static _Unwind_Reason_Code
trace_callback(struct _Unwind_Context * uw_context,uw_data_t * uw_data)63 trace_callback (struct _Unwind_Context * uw_context, uw_data_t * uw_data)
64 {
65 char * pc;
66
67 #if defined (__ia64__) && defined (__hpux__) && defined (USE_LIBUNWIND_EXCEPTIONS)
68 /* Work around problem with _Unwind_GetIP on ia64 HP-UX. */
69 uwx_get_reg ((struct uwx_env *) uw_context, UWX_REG_IP, (uint64_t *) &pc);
70 #else
71 pc = (char *) _Unwind_GetIP (uw_context);
72 #endif
73
74 if (uw_data->n_frames_skipped < uw_data->n_frames_to_skip)
75 {
76 uw_data->n_frames_skipped ++;
77 return _URC_NO_REASON;
78 }
79
80 if (uw_data->n_entries_filled >= uw_data->max_len)
81 return _URC_NORMAL_STOP;
82
83 if (pc < (char *)uw_data->exclude_min || pc > (char *)uw_data->exclude_max)
84 uw_data->traceback [uw_data->n_entries_filled ++] = pc + PC_ADJUST;
85
86 return _URC_NO_REASON;
87 }
88
89 #endif
90
91 /********************
92 * __gnat_backtrace *
93 ********************/
94
95 int
__gnat_backtrace(void ** traceback,int max_len,void * exclude_min,void * exclude_max,int skip_frames)96 __gnat_backtrace (void ** traceback __attribute__((unused)),
97 int max_len __attribute__((unused)),
98 void * exclude_min __attribute__((unused)),
99 void * exclude_max __attribute__((unused)),
100 int skip_frames __attribute__((unused)))
101 {
102 #if defined (__USING_SJLJ_EXCEPTIONS__)
103 /* We have no unwind material (tables) at hand with sjlj eh, and no
104 way to retrieve complete and accurate call chain information from
105 the context stack we maintain. */
106 return 0;
107 #else
108 uw_data_t uw_data;
109 /* State carried over during the whole unwinding process. */
110
111 uw_data.traceback = traceback;
112 uw_data.max_len = max_len;
113 uw_data.exclude_min = exclude_min;
114 uw_data.exclude_max = exclude_max;
115
116 uw_data.n_frames_to_skip = skip_frames;
117
118 uw_data.n_frames_skipped = 0;
119 uw_data.n_entries_filled = 0;
120
121 _Unwind_Backtrace ((_Unwind_Trace_Fn)trace_callback, &uw_data);
122
123 return uw_data.n_entries_filled;
124 #endif
125 }
126