forked from OSchip/llvm-project
90 lines
3.0 KiB
C++
90 lines
3.0 KiB
C++
//===-- Process.cpp - Implement OS Process Concept --------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This header file implements the operating system Process concept.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Config/config.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/Process.h"
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using namespace llvm;
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using namespace sys;
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//===----------------------------------------------------------------------===//
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//=== WARNING: Implementation here must contain only TRULY operating system
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//=== independent code.
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//===----------------------------------------------------------------------===//
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// Empty virtual destructor to anchor the vtable for the process class.
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process::~process() {}
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self_process *process::get_self() {
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// Use a function local static for thread safe initialization and allocate it
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// as a raw pointer to ensure it is never destroyed.
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static self_process *SP = new self_process();
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return SP;
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}
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#if defined(_MSC_VER)
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// Visual Studio complains that the self_process destructor never exits. This
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// doesn't make much sense, as that's the whole point of calling abort... Just
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// silence this warning.
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#pragma warning(push)
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#pragma warning(disable:4722)
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#endif
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// The destructor for the self_process subclass must never actually be
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// executed. There should be at most one instance of this class, and that
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// instance should live until the process terminates to avoid the potential for
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// racy accesses during shutdown.
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self_process::~self_process() {
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llvm_unreachable("This destructor must never be executed!");
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}
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/// \brief A helper function to compute the elapsed wall-time since the program
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/// started.
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///
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/// Note that this routine actually computes the elapsed wall time since the
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/// first time it was called. However, we arrange to have it called during the
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/// startup of the process to get approximately correct results.
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static TimeValue getElapsedWallTime() {
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static TimeValue &StartTime = *new TimeValue(TimeValue::now());
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return TimeValue::now() - StartTime;
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}
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/// \brief A special global variable to ensure we call \c getElapsedWallTime
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/// during global initialization of the program.
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///
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/// Note that this variable is never referenced elsewhere. Doing so could
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/// create race conditions during program startup or shutdown.
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static volatile TimeValue DummyTimeValue = getElapsedWallTime();
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// Implement this routine by using the static helpers above. They're already
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// portable.
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TimeValue self_process::get_wall_time() const {
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return getElapsedWallTime();
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}
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#if defined(_MSC_VER)
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#pragma warning(pop)
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#endif
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// Include the platform-specific parts of this class.
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#ifdef LLVM_ON_UNIX
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#include "Unix/Process.inc"
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#endif
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#ifdef LLVM_ON_WIN32
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#include "Windows/Process.inc"
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#endif
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