1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
|
/* go-callers.c -- get callers for Go.
Copyright 2012 The Go Authors. All rights reserved.
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file. */
#include "config.h"
#include "backtrace.h"
#include "runtime.h"
#include "array.h"
/* This is set to non-zero when calling backtrace_full. This is used
to avoid getting hanging on a recursive lock in dl_iterate_phdr on
older versions of glibc when a SIGPROF signal arrives while
collecting a backtrace. */
uint32 runtime_in_callers;
/* Argument passed to callback function. */
struct callers_data
{
Location *locbuf;
int skip;
int index;
int max;
int keep_thunks;
};
/* Callback function for backtrace_full. Just collect the locations.
Return zero to continue, non-zero to stop. */
static int
callback (void *data, uintptr_t pc, const char *filename, int lineno,
const char *function)
{
struct callers_data *arg = (struct callers_data *) data;
Location *loc;
/* Skip split stack functions. */
if (function != NULL)
{
const char *p;
p = function;
if (__builtin_strncmp (p, "___", 3) == 0)
++p;
if (__builtin_strncmp (p, "__morestack_", 12) == 0)
return 0;
}
else if (filename != NULL)
{
const char *p;
p = strrchr (filename, '/');
if (p == NULL)
p = filename;
if (__builtin_strncmp (p, "/morestack.S", 12) == 0)
return 0;
}
/* Skip thunks and recover functions. There is no equivalent to
these functions in the gc toolchain, so returning them here means
significantly different results for runtime.Caller(N). */
if (function != NULL && !arg->keep_thunks)
{
const char *p;
p = __builtin_strchr (function, '.');
if (p != NULL && __builtin_strncmp (p + 1, "$thunk", 6) == 0)
return 0;
p = __builtin_strrchr (function, '$');
if (p != NULL && __builtin_strcmp(p, "$recover") == 0)
return 0;
}
if (arg->skip > 0)
{
--arg->skip;
return 0;
}
loc = &arg->locbuf[arg->index];
loc->pc = pc;
/* The libbacktrace library says that these strings might disappear,
but with the current implementation they won't. We can't easily
allocate memory here, so for now assume that we can save a
pointer to the strings. */
loc->filename = runtime_gostringnocopy ((const byte *) filename);
loc->function = runtime_gostringnocopy ((const byte *) function);
loc->lineno = lineno;
++arg->index;
/* There is no point to tracing past certain runtime functions.
Stopping the backtrace here can avoid problems on systems that
don't provide proper unwind information for makecontext, such as
Solaris (http://gcc.gnu.org/PR52583 comment #21). */
if (function != NULL)
{
if (__builtin_strcmp (function, "makecontext") == 0)
return 1;
if (filename != NULL)
{
const char *p;
p = strrchr (filename, '/');
if (p == NULL)
p = filename;
if (__builtin_strcmp (p, "/proc.c") == 0)
{
if (__builtin_strcmp (function, "kickoff") == 0
|| __builtin_strcmp (function, "runtime_mstart") == 0
|| __builtin_strcmp (function, "runtime_main") == 0)
return 1;
}
}
}
return arg->index >= arg->max;
}
/* Error callback. */
static void
error_callback (void *data __attribute__ ((unused)),
const char *msg, int errnum)
{
if (errnum == -1)
{
/* No debug info available. Carry on as best we can. */
return;
}
if (errnum != 0)
runtime_printf ("%s errno %d\n", msg, errnum);
runtime_throw (msg);
}
/* Gather caller PC's. */
int32
runtime_callers (int32 skip, Location *locbuf, int32 m, bool keep_thunks)
{
struct callers_data data;
data.locbuf = locbuf;
data.skip = skip + 1;
data.index = 0;
data.max = m;
data.keep_thunks = keep_thunks;
runtime_xadd (&runtime_in_callers, 1);
backtrace_full (__go_get_backtrace_state (), 0, callback, error_callback,
&data);
runtime_xadd (&runtime_in_callers, -1);
return data.index;
}
int Callers (int, struct __go_open_array)
__asm__ (GOSYM_PREFIX "runtime.Callers");
int
Callers (int skip, struct __go_open_array pc)
{
Location *locbuf;
int ret;
int i;
locbuf = (Location *) runtime_mal (pc.__count * sizeof (Location));
/* In the Go 1 release runtime.Callers has an off-by-one error,
which we can not correct because it would break backward
compatibility. Normally we would add 1 to SKIP here, but we
don't so that we are compatible. */
ret = runtime_callers (skip, locbuf, pc.__count, false);
for (i = 0; i < ret; i++)
((uintptr *) pc.__values)[i] = locbuf[i].pc;
return ret;
}
|
