1 /* go-callers.c -- get callers for Go.
3 Copyright 2012 The Go Authors. All rights reserved.
4 Use of this source code is governed by a BSD-style
5 license that can be found in the LICENSE file. */
14 /* This is set to non-zero when calling backtrace_full. This is used
15 to avoid getting hanging on a recursive lock in dl_iterate_phdr on
16 older versions of glibc when a SIGPROF signal arrives while
17 collecting a backtrace. */
19 uint32 runtime_in_callers
;
21 /* Argument passed to callback function. */
32 /* Callback function for backtrace_full. Just collect the locations.
33 Return zero to continue, non-zero to stop. */
36 callback (void *data
, uintptr_t pc
, const char *filename
, int lineno
,
39 struct callers_data
*arg
= (struct callers_data
*) data
;
42 /* Skip split stack functions. */
48 if (__builtin_strncmp (p
, "___", 3) == 0)
50 if (__builtin_strncmp (p
, "__morestack_", 12) == 0)
53 else if (filename
!= NULL
)
57 p
= strrchr (filename
, '/');
60 if (__builtin_strncmp (p
, "/morestack.S", 12) == 0)
64 /* Skip thunks and recover functions. There is no equivalent to
65 these functions in the gc toolchain, so returning them here means
66 significantly different results for runtime.Caller(N). */
67 if (function
!= NULL
&& !arg
->keep_thunks
)
71 p
= __builtin_strchr (function
, '.');
72 if (p
!= NULL
&& __builtin_strncmp (p
+ 1, "$thunk", 6) == 0)
74 p
= __builtin_strrchr (function
, '$');
75 if (p
!= NULL
&& __builtin_strcmp(p
, "$recover") == 0)
85 loc
= &arg
->locbuf
[arg
->index
];
88 /* The libbacktrace library says that these strings might disappear,
89 but with the current implementation they won't. We can't easily
90 allocate memory here, so for now assume that we can save a
91 pointer to the strings. */
92 loc
->filename
= runtime_gostringnocopy ((const byte
*) filename
);
93 loc
->function
= runtime_gostringnocopy ((const byte
*) function
);
98 /* There is no point to tracing past certain runtime functions.
99 Stopping the backtrace here can avoid problems on systems that
100 don't provide proper unwind information for makecontext, such as
101 Solaris (http://gcc.gnu.org/PR52583 comment #21). */
102 if (function
!= NULL
)
104 if (__builtin_strcmp (function
, "makecontext") == 0)
106 if (filename
!= NULL
)
110 p
= strrchr (filename
, '/');
113 if (__builtin_strcmp (p
, "/proc.c") == 0)
115 if (__builtin_strcmp (function
, "kickoff") == 0
116 || __builtin_strcmp (function
, "runtime_mstart") == 0
117 || __builtin_strcmp (function
, "runtime_main") == 0)
123 return arg
->index
>= arg
->max
;
126 /* Error callback. */
129 error_callback (void *data
__attribute__ ((unused
)),
130 const char *msg
, int errnum
)
133 runtime_printf ("%s errno %d\n", msg
, errnum
);
137 /* Gather caller PC's. */
140 runtime_callers (int32 skip
, Location
*locbuf
, int32 m
, bool keep_thunks
)
142 struct callers_data data
;
144 data
.locbuf
= locbuf
;
145 data
.skip
= skip
+ 1;
148 data
.keep_thunks
= keep_thunks
;
149 runtime_xadd (&runtime_in_callers
, 1);
150 backtrace_full (__go_get_backtrace_state (), 0, callback
, error_callback
,
152 runtime_xadd (&runtime_in_callers
, -1);
156 int Callers (int, struct __go_open_array
)
157 __asm__ (GOSYM_PREFIX
"runtime.Callers");
160 Callers (int skip
, struct __go_open_array pc
)
166 locbuf
= (Location
*) runtime_mal (pc
.__count
* sizeof (Location
));
168 /* In the Go 1 release runtime.Callers has an off-by-one error,
169 which we can not correct because it would break backward
170 compatibility. Normally we would add 1 to SKIP here, but we
171 don't so that we are compatible. */
172 ret
= runtime_callers (skip
, locbuf
, pc
.__count
, false);
174 for (i
= 0; i
< ret
; i
++)
175 ((uintptr
*) pc
.__values
)[i
] = locbuf
[i
].pc
;