-// Copyright 2000 - 2007 Google Inc.
+// Copyright (c) 2000 - 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.
+//
// Produce stack trace
#include <stdint.h> // for uintptr_t
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 **sp;
-#ifdef __i386__
- // Stack frame format:
- // sp[0] pointer to previous frame
- // sp[1] caller address
- // sp[2] first argument
- // ...
- sp = (void **)&pcs - 2;
-#endif
-
-#ifdef __x86_64__
- // __builtin_frame_address(0) can return the wrong address on gcc-4.1.0-k8
- unsigned long rbp;
- // Move the value of the register %rbp into the local variable rbp.
- // We need 'volatile' to prevent this instruction from getting moved
- // around during optimization to before function prologue is done.
- // An alternative way to achieve this
- // would be (before this __asm__ instruction) to call Noop() defined as
- // static void Noop() __attribute__ ((noinline)); // prevent inlining
- // static void Noop() { asm(""); } // prevent optimizing-away
- __asm__ volatile ("mov %%rbp, %0" : "=r" (rbp));
- // Arguments are passed in registers on x86-64, so we can't just
- // offset from &pcs
- sp = (void **) rbp;
-#endif
-
- int n = 0;
- while (sp && n < max_depth) {
- if (*(sp+1) == (void *)0) {
- // In 64-bit code, we often see a frame that
- // points to itself and has a return address of 0.
- break;
- }
- // The GetStackFrames routine is called when we are in some
- // informational context (the failure signal handler for example).
- // Use the non-strict unwinding rules to produce a stack trace
- // that is as complete as possible (even if it contains a few bogus
- // entries in some rare cases).
- void **next_sp = NextStackFrame<false>(sp);
- if (skip_count > 0) {
- skip_count--;
- } else {
- pcs[n] = *(sp+1);
- if (next_sp > sp) {
- sizes[n] = (uintptr_t)next_sp - (uintptr_t)sp;
- } else {
- // A frame-size of 0 is used to indicate unknown frame size.
- sizes[n] = 0;
- }
- n++;
- }
- sp = next_sp;
- }
- return n;
-}
-
_END_GOOGLE_NAMESPACE_
projects / platform / upstream / glog.git / blobdiff