100 lines
3.8 KiB
C++
100 lines
3.8 KiB
C++
// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*-
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// Copyright (c) 2005, Google Inc.
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// ---
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// Author: Craig Silverstein
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//
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// This is an internal header file used by profiler.cc. It defines
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// the single (inline) function GetPC. GetPC is used in a signal
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// handler to figure out the instruction that was being executed when
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// the signal-handler was triggered.
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//
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// To get this, we use the ucontext_t argument to the signal-handler
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// callback, which holds the full context of what was going on when
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// the signal triggered. How to get from a ucontext_t to a Program
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// Counter is OS-dependent.
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#ifndef BASE_GETPC_H_
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#define BASE_GETPC_H_
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// Note: we include this from one of configure script C++ tests as
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// part of verifying that we're able to build CPU profiler. I.e. we
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// cannot include config.h as we normally do, since it isn't produced
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// yet, but those HAVE_XYZ defines are available, so including
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// ucontext etc stuff works. It's usage from profiler.cc (and
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// stacktrace_generic_fp-inl.h) is after config.h is included.
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// On many linux systems, we may need _GNU_SOURCE to get access to
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// the defined constants that define the register we want to see (eg
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// REG_EIP). Note this #define must come first!
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#define _GNU_SOURCE 1
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#ifdef HAVE_ASM_PTRACE_H
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#include <asm/ptrace.h>
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#endif
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#if HAVE_SYS_UCONTEXT_H
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#include <sys/ucontext.h>
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#elif HAVE_UCONTEXT_H
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#include <ucontext.h> // for ucontext_t (and also mcontext_t)
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#elif defined(HAVE_CYGWIN_SIGNAL_H)
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#include <cygwin/signal.h>
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typedef ucontext ucontext_t;
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#endif
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namespace tcmalloc {
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namespace getpc {
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// std::void_t is C++ 14. So we steal this from
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// https://en.cppreference.com/w/cpp/types/void_t
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template<typename... Ts>
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struct make_void { typedef void type; };
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template <typename... Ts>
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using void_t = typename make_void<Ts...>::type;
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#include "getpc-inl.h"
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} // namespace getpc
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} // namespace tcmalloc
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// If this doesn't compile, you need to figure out the right value for
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// your system, and add it to the list above.
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inline void* GetPC(const ucontext_t& signal_ucontext) {
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void* retval = tcmalloc::getpc::internal::RawUCToPC(&signal_ucontext);
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#if defined(__s390__) && !defined(__s390x__)
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// Mask out the AMODE31 bit from the PC recorded in the context.
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retval = (void*)((unsigned long)retval & 0x7fffffffUL);
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#endif
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return retval;
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}
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#endif // BASE_GETPC_H_
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