-// Copyright 2005 - 2007 Google Inc.
+// Copyright (c) 2005 - 2007, Google Inc.
// All rights reserved.
//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
// Author: Arun Sharma
//
// Produce stack trace using libunwind
+#include "utilities.h"
+
extern "C" {
+#define UNW_LOCAL_ONLY
#include <libunwind.h>
}
-#include "base/stacktrace.h"
-#include "base/raw_logging.h"
-#include "base/spinlock.h"
+#include "glog/raw_logging.h"
+#include "stacktrace.h"
_START_GOOGLE_NAMESPACE_
// Sometimes, we can try to get a stack trace from within a stack
-// trace, because libunwind can call mmap/sbrk (maybe indirectly via
-// malloc), and that mmap gets trapped and causes a stack-trace
-// request. If were to try to honor that recursive request, we'd end
-// up with infinite recursion or deadlock. Luckily, it's safe to
-// ignore those subsequent traces. In such cases, we return 0 to
-// indicate the situation.
-static SpinLock libunwind_lock(SpinLock::LINKER_INITIALIZED);
+// trace, because libunwind can call mmap (maybe indirectly via an
+// internal mmap based memory allocator), and that mmap gets trapped
+// and causes a stack-trace request. If were to try to honor that
+// recursive request, we'd end up with infinite recursion or deadlock.
+// Luckily, it's safe to ignore those subsequent traces. In such
+// cases, we return 0 to indicate the situation.
+static bool g_now_entering = false;
// If you change this function, also change GetStackFrames below.
int GetStackTrace(void** result, int max_depth, int skip_count) {
unw_cursor_t cursor;
unw_context_t uc;
- if (!libunwind_lock.TryLock()) {
+ if (sync_val_compare_and_swap(&g_now_entering, false, true)) {
return 0;
}
break;
}
- libunwind_lock.Unlock();
- return n;
-}
-
-// If you change this function, also change GetStackTrace above:
-//
-// This GetStackFrames routine shares a lot of code with GetStackTrace
-// above. This code could have been refactored into a common routine,
-// and then both GetStackTrace/GetStackFrames could call that routine.
-// There are two problems with that:
-//
-// (1) The performance of the refactored-code suffers substantially - the
-// refactored needs to be able to record the stack trace when called
-// from GetStackTrace, and both the stack trace and stack frame sizes,
-// when called from GetStackFrames - this introduces enough new
-// conditionals that GetStackTrace performance can degrade by as much
-// as 50%.
-//
-// (2) Whether the refactored routine gets inlined into GetStackTrace and
-// GetStackFrames depends on the compiler, and we can't guarantee the
-// behavior either-way, even with "__attribute__ ((always_inline))"
-// or "__attribute__ ((noinline))". But we need this guarantee or the
-// frame counts may be off by one.
-//
-// Both (1) and (2) can be addressed without this code duplication, by
-// clever use of template functions, and by defining GetStackTrace and
-// GetStackFrames as macros that expand to these template functions.
-// However, this approach comes with its own set of problems - namely,
-// macros and preprocessor trouble - for example, if GetStackTrace
-// and/or GetStackFrames is ever defined as a member functions in some
-// class, we are in trouble.
-int GetStackFrames(void** pcs, int* sizes, int max_depth, int skip_count) {
- void *ip;
- int n = 0;
- unw_cursor_t cursor;
- unw_context_t uc;
- unw_word_t sp = 0, next_sp = 0;
-
- if (!libunwind_lock.TryLock()) {
- return 0;
- }
-
- unw_getcontext(&uc);
- RAW_CHECK(unw_init_local(&cursor, &uc) >= 0, "unw_init_local failed");
- skip_count++; // Do not include the "GetStackFrames" frame
-
- while (skip_count--) {
- if (unw_step(&cursor) <= 0 ||
- unw_get_reg(&cursor, UNW_REG_SP, &next_sp) < 0) {
- goto out;
- }
- }
- while (n < max_depth) {
- sp = next_sp;
- if (unw_get_reg(&cursor, UNW_REG_IP, (unw_word_t *) &ip) < 0)
- break;
- if (unw_step(&cursor) <= 0 ||
- unw_get_reg(&cursor, UNW_REG_SP, &next_sp)) {
- // We couldn't step any further (possibly because we reached _start).
- // Provide the last good PC we've got, and get out.
- sizes[n] = 0;
- pcs[n++] = ip;
- break;
- }
- sizes[n] = next_sp - sp;
- pcs[n++] = ip;
- }
- out:
- libunwind_lock.Unlock();
+ g_now_entering = false;
return n;
}
projects / platform / upstream / glog.git / blobdiff