gcc/
[official-gcc.git] / libgfortran / runtime / backtrace.c
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1 /* Copyright (C) 2006-2018 Free Software Foundation, Inc.
2 Contributed by François-Xavier Coudert
4 This file is part of the GNU Fortran runtime library (libgfortran).
6 Libgfortran 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 Libgfortran 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 #include "libgfortran.h"
27 #include <gthr.h>
29 #include <string.h>
30 #include <errno.h>
32 #ifdef HAVE_UNISTD_H
33 #include <unistd.h>
34 #endif
36 #include "backtrace-supported.h"
37 #include "backtrace.h"
40 /* Store our own state while backtracing. */
41 struct mystate
43 int frame;
44 bool try_simple;
45 bool in_signal_handler;
49 /* Does a function name have "_gfortran_" or "_gfortrani_" prefix, possibly
50 with additional underscore(s) at the beginning? Cannot use strncmp()
51 because we might be called from a signal handler. */
53 static int
54 has_gfortran_prefix (const char *s)
56 if (!s)
57 return 0;
59 while (*s == '_')
60 s++;
62 return (s[0] == 'g' && s[1] == 'f' && s[2] == 'o' && s[3] == 'r'
63 && s[4] == 't' && s[5] == 'r' && s[6] == 'a' && s[7] == 'n'
64 && (s[8] == '_' || (s[8] == 'i' && s[9] == '_')));
67 static void
68 error_callback (void *data, const char *msg, int errnum)
70 struct mystate *state = (struct mystate *) data;
71 struct iovec iov[5];
72 #define ERRHDR "\nCould not print backtrace: "
74 if (errnum < 0)
76 state->try_simple = true;
77 return;
79 else if (errnum == 0)
81 iov[0].iov_base = (char*) ERRHDR;
82 iov[0].iov_len = strlen (ERRHDR);
83 iov[1].iov_base = (char*) msg;
84 iov[1].iov_len = strlen (msg);
85 iov[2].iov_base = (char*) "\n";
86 iov[2].iov_len = 1;
87 estr_writev (iov, 3);
89 else
91 char errbuf[256];
92 if (state->in_signal_handler)
94 iov[0].iov_base = (char*) ERRHDR;
95 iov[0].iov_len = strlen (ERRHDR);
96 iov[1].iov_base = (char*) msg;
97 iov[1].iov_len = strlen (msg);
98 iov[2].iov_base = (char*) ", errno: ";
99 iov[2].iov_len = strlen (iov[2].iov_base);
100 const char *p = gfc_itoa (errnum, errbuf, sizeof (errbuf));
101 iov[3].iov_base = (char*) p;
102 iov[3].iov_len = strlen (p);
103 iov[4].iov_base = (char*) "\n";
104 iov[4].iov_len = 1;
105 estr_writev (iov, 5);
107 else
108 st_printf (ERRHDR "%s: %s\n", msg,
109 gf_strerror (errnum, errbuf, sizeof (errbuf)));
113 static int
114 simple_callback (void *data, uintptr_t pc)
116 struct mystate *state = (struct mystate *) data;
117 st_printf ("#%d 0x%lx\n", state->frame, (unsigned long) pc);
118 (state->frame)++;
119 return 0;
122 static int
123 full_callback (void *data, uintptr_t pc, const char *filename,
124 int lineno, const char *function)
126 struct mystate *state = (struct mystate *) data;
128 if (has_gfortran_prefix (function))
129 return 0;
131 st_printf ("#%d 0x%lx in %s\n", state->frame,
132 (unsigned long) pc, function == NULL ? "???" : function);
133 if (filename || lineno != 0)
134 st_printf ("\tat %s:%d\n", filename == NULL ? "???" : filename, lineno);
135 (state->frame)++;
137 if (function != NULL && strcmp (function, "main") == 0)
138 return 1;
140 return 0;
144 /* Display the backtrace. */
146 void
147 show_backtrace (bool in_signal_handler)
149 struct backtrace_state *lbstate;
150 struct mystate state = { 0, false, in_signal_handler };
152 lbstate = backtrace_create_state (NULL, __gthread_active_p (),
153 error_callback, NULL);
155 if (lbstate == NULL)
156 return;
158 if (!BACKTRACE_SUPPORTED || (in_signal_handler && BACKTRACE_USES_MALLOC))
160 /* If symbolic backtrace is not supported on this target, or would
161 require malloc() and we are in a signal handler, go with a
162 simple backtrace. */
164 backtrace_simple (lbstate, 0, simple_callback, error_callback, &state);
166 else
168 /* libbacktrace uses mmap, which is safe to call from a signal handler
169 (in practice, if not in theory). Thus we can generate a symbolic
170 backtrace, if debug symbols are available. */
172 backtrace_full (lbstate, 0, full_callback, error_callback, &state);
173 if (state.try_simple)
174 backtrace_simple (lbstate, 0, simple_callback, error_callback, &state);
180 /* Function called by the front-end translating the BACKTRACE intrinsic. */
182 extern void backtrace (void);
183 export_proto (backtrace);
185 void
186 backtrace (void)
188 show_backtrace (false);