Coverage Report

Created: 2019-07-24 05:18

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/include/llvm/Support/Process.h
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//===- llvm/Support/Process.h -----------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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/// \file
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///
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/// Provides a library for accessing information about this process and other
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/// processes on the operating system. Also provides means of spawning
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/// subprocess for commands. The design of this library is modeled after the
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/// proposed design of the Boost.Process library, and is design specifically to
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/// follow the style of standard libraries and potentially become a proposal
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/// for a standard library.
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///
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/// This file declares the llvm::sys::Process class which contains a collection
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/// of legacy static interfaces for extracting various information about the
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/// current process. The goal is to migrate users of this API over to the new
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/// interfaces.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_SUPPORT_PROCESS_H
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#define LLVM_SUPPORT_PROCESS_H
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#include "llvm/ADT/Optional.h"
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#include "llvm/Support/Allocator.h"
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#include "llvm/Support/Chrono.h"
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#include "llvm/Support/DataTypes.h"
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#include "llvm/Support/Error.h"
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#include <system_error>
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namespace llvm {
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template <typename T> class ArrayRef;
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class StringRef;
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namespace sys {
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/// A collection of legacy interfaces for querying information about the
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/// current executing process.
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class Process {
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public:
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  /// Get the process's page size.
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  /// This may fail if the underlying syscall returns an error. In most cases,
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  /// page size information is used for optimization, and this error can be
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  /// safely discarded by calling consumeError, and an estimated page size
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  /// substituted instead.
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  static Expected<unsigned> getPageSize();
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  /// Get the process's estimated page size.
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  /// This function always succeeds, but if the underlying syscall to determine
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  /// the page size fails then this will silently return an estimated page size.
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  /// The estimated page size is guaranteed to be a power of 2.
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  static unsigned getPageSizeEstimate() {
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    if (auto PageSize = getPageSize())
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      return *PageSize;
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0
    else {
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0
      consumeError(PageSize.takeError());
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0
      return 4096;
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0
    }
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  }
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  /// Return process memory usage.
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  /// This static function will return the total amount of memory allocated
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  /// by the process. This only counts the memory allocated via the malloc,
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  /// calloc and realloc functions and includes any "free" holes in the
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  /// allocated space.
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  static size_t GetMallocUsage();
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  /// This static function will set \p user_time to the amount of CPU time
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  /// spent in user (non-kernel) mode and \p sys_time to the amount of CPU
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  /// time spent in system (kernel) mode.  If the operating system does not
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  /// support collection of these metrics, a zero duration will be for both
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  /// values.
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  /// \param elapsed Returns the system_clock::now() giving current time
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  /// \param user_time Returns the current amount of user time for the process
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  /// \param sys_time Returns the current amount of system time for the process
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  static void GetTimeUsage(TimePoint<> &elapsed,
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                           std::chrono::nanoseconds &user_time,
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                           std::chrono::nanoseconds &sys_time);
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  /// This function makes the necessary calls to the operating system to
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  /// prevent core files or any other kind of large memory dumps that can
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  /// occur when a program fails.
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  /// Prevent core file generation.
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  static void PreventCoreFiles();
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  /// true if PreventCoreFiles has been called, false otherwise.
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  static bool AreCoreFilesPrevented();
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  // This function returns the environment variable \arg name's value as a UTF-8
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  // string. \arg Name is assumed to be in UTF-8 encoding too.
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  static Optional<std::string> GetEnv(StringRef name);
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  /// This function searches for an existing file in the list of directories
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  /// in a PATH like environment variable, and returns the first file found,
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  /// according to the order of the entries in the PATH like environment
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  /// variable.  If an ignore list is specified, then any folder which is in
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  /// the PATH like environment variable but is also in IgnoreList is not
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  /// considered.
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  static Optional<std::string> FindInEnvPath(StringRef EnvName,
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                                             StringRef FileName,
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                                             ArrayRef<std::string> IgnoreList);
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  static Optional<std::string> FindInEnvPath(StringRef EnvName,
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                                             StringRef FileName);
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  // This functions ensures that the standard file descriptors (input, output,
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  // and error) are properly mapped to a file descriptor before we use any of
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  // them.  This should only be called by standalone programs, library
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  // components should not call this.
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  static std::error_code FixupStandardFileDescriptors();
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  // This function safely closes a file descriptor.  It is not safe to retry
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  // close(2) when it returns with errno equivalent to EINTR; this is because
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  // *nixen cannot agree if the file descriptor is, in fact, closed when this
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  // occurs.
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  //
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  // N.B. Some operating systems, due to thread cancellation, cannot properly
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  // guarantee that it will or will not be closed one way or the other!
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  static std::error_code SafelyCloseFileDescriptor(int FD);
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  /// This function determines if the standard input is connected directly
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  /// to a user's input (keyboard probably), rather than coming from a file
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  /// or pipe.
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  static bool StandardInIsUserInput();
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  /// This function determines if the standard output is connected to a
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  /// "tty" or "console" window. That is, the output would be displayed to
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  /// the user rather than being put on a pipe or stored in a file.
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  static bool StandardOutIsDisplayed();
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  /// This function determines if the standard error is connected to a
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  /// "tty" or "console" window. That is, the output would be displayed to
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  /// the user rather than being put on a pipe or stored in a file.
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  static bool StandardErrIsDisplayed();
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  /// This function determines if the given file descriptor is connected to
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  /// a "tty" or "console" window. That is, the output would be displayed to
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  /// the user rather than being put on a pipe or stored in a file.
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  static bool FileDescriptorIsDisplayed(int fd);
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  /// This function determines if the given file descriptor is displayd and
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  /// supports colors.
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  static bool FileDescriptorHasColors(int fd);
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  /// This function determines the number of columns in the window
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  /// if standard output is connected to a "tty" or "console"
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  /// window. If standard output is not connected to a tty or
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  /// console, or if the number of columns cannot be determined,
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  /// this routine returns zero.
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  static unsigned StandardOutColumns();
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  /// This function determines the number of columns in the window
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  /// if standard error is connected to a "tty" or "console"
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  /// window. If standard error is not connected to a tty or
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  /// console, or if the number of columns cannot be determined,
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  /// this routine returns zero.
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  static unsigned StandardErrColumns();
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  /// This function determines whether the terminal connected to standard
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  /// output supports colors. If standard output is not connected to a
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  /// terminal, this function returns false.
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  static bool StandardOutHasColors();
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  /// This function determines whether the terminal connected to standard
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  /// error supports colors. If standard error is not connected to a
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  /// terminal, this function returns false.
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  static bool StandardErrHasColors();
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  /// Enables or disables whether ANSI escape sequences are used to output
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  /// colors. This only has an effect on Windows.
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  /// Note: Setting this option is not thread-safe and should only be done
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  /// during initialization.
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  static void UseANSIEscapeCodes(bool enable);
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  /// Whether changing colors requires the output to be flushed.
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  /// This is needed on systems that don't support escape sequences for
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  /// changing colors.
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  static bool ColorNeedsFlush();
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  /// This function returns the colorcode escape sequences.
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  /// If ColorNeedsFlush() is true then this function will change the colors
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  /// and return an empty escape sequence. In that case it is the
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  /// responsibility of the client to flush the output stream prior to
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  /// calling this function.
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  static const char *OutputColor(char c, bool bold, bool bg);
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  /// Same as OutputColor, but only enables the bold attribute.
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  static const char *OutputBold(bool bg);
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  /// This function returns the escape sequence to reverse forground and
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  /// background colors.
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  static const char *OutputReverse();
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  /// Resets the terminals colors, or returns an escape sequence to do so.
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  static const char *ResetColor();
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  /// Get the result of a process wide random number generator. The
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  /// generator will be automatically seeded in non-deterministic fashion.
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  static unsigned GetRandomNumber();
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};
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}
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}
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#endif