include/llvm/Support/Program.h

   1 //===- llvm/Support/Program.h ------------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file declares the llvm::sys::Program class.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifndef LLVM_SUPPORT_PROGRAM_H
  14 #define LLVM_SUPPORT_PROGRAM_H
  15
  16 #include "llvm/ADT/ArrayRef.h"
  17 #include "llvm/ADT/Optional.h"
  18 #include "llvm/ADT/StringRef.h"
  19 #include "llvm/Config/llvm-config.h"
  20 #include "llvm/Support/ErrorOr.h"
  21 #include <system_error>
  22
  23 namespace llvm {
  24 namespace sys {
  25
  26   /// This is the OS-specific separator for PATH like environment variables:
  27   // a colon on Unix or a semicolon on Windows.
  28 #if defined(LLVM_ON_UNIX)
  29   const char EnvPathSeparator = ':';
  30 #elif defined (_WIN32)
  31   const char EnvPathSeparator = ';';
  32 #endif
  33
  34 #if defined(_WIN32)
  35   typedef unsigned long procid_t; // Must match the type of DWORD on Windows.
  36   typedef void *process_t;        // Must match the type of HANDLE on Windows.
  37 #else
  38   typedef pid_t procid_t;
  39   typedef procid_t process_t;
  40 #endif
  41
  42   /// This struct encapsulates information about a process.
  43   struct ProcessInfo {
  44     enum : procid_t { InvalidPid = 0 };
  45
  46     procid_t Pid;      /// The process identifier.
  47     process_t Process; /// Platform-dependent process object.
  48
  49     /// The return code, set after execution.
  50     int ReturnCode;
  51
  52     ProcessInfo();
  53   };
  54
  55   /// Find the first executable file \p Name in \p Paths.
  56   ///
  57   /// This does not perform hashing as a shell would but instead stats each PATH
  58   /// entry individually so should generally be avoided. Core LLVM library
  59   /// functions and options should instead require fully specified paths.
  60   ///
  61   /// \param Name name of the executable to find. If it contains any system
  62   ///   slashes, it will be returned as is.
  63   /// \param Paths optional list of paths to search for \p Name. If empty it
  64   ///   will use the system PATH environment instead.
  65   ///
  66   /// \returns The fully qualified path to the first \p Name in \p Paths if it
  67   ///   exists. \p Name if \p Name has slashes in it. Otherwise an error.
  68   ErrorOr<std::string>
  69   findProgramByName(StringRef Name, ArrayRef<StringRef> Paths = {});
  70
  71   // These functions change the specified standard stream (stdin or stdout) to
  72   // binary mode. They return errc::success if the specified stream
  73   // was changed. Otherwise a platform dependent error is returned.
  74   std::error_code ChangeStdinToBinary();
  75   std::error_code ChangeStdoutToBinary();
  76
  77   /// This function executes the program using the arguments provided.  The
  78   /// invoked program will inherit the stdin, stdout, and stderr file
  79   /// descriptors, the environment and other configuration settings of the
  80   /// invoking program.
  81   /// This function waits for the program to finish, so should be avoided in
  82   /// library functions that aren't expected to block. Consider using
  83   /// ExecuteNoWait() instead.
  84   /// \returns an integer result code indicating the status of the program.
  85   /// A zero or positive value indicates the result code of the program.
  86   /// -1 indicates failure to execute
  87   /// -2 indicates a crash during execution or timeout
  88   int ExecuteAndWait(
  89       StringRef Program, ///< Path of the program to be executed. It is
  90       ///< presumed this is the result of the findProgramByName method.
  91       ArrayRef<StringRef> Args, ///< An array of strings that are passed to the
  92       ///< program.  The first element should be the name of the program.
  93       ///< The array should **not** be terminated by an empty StringRef.
  94       Optional<ArrayRef<StringRef>> Env = None, ///< An optional vector of
  95       ///< strings to use for the program's environment. If not provided, the
  96       ///< current program's environment will be used.  If specified, the
  97       ///< vector should **not** be terminated by an empty StringRef.
  98       ArrayRef<Optional<StringRef>> Redirects = {}, ///<
  99       ///< An array of optional paths. Should have a size of zero or three.
 100       ///< If the array is empty, no redirections are performed.
 101       ///< Otherwise, the inferior process's stdin(0), stdout(1), and stderr(2)
 102       ///< will be redirected to the corresponding paths, if the optional path
 103       ///< is present (not \c llvm::None).
 104       ///< When an empty path is passed in, the corresponding file descriptor
 105       ///< will be disconnected (ie, /dev/null'd) in a portable way.
 106       unsigned SecondsToWait = 0, ///< If non-zero, this specifies the amount
 107       ///< of time to wait for the child process to exit. If the time
 108       ///< expires, the child is killed and this call returns. If zero,
 109       ///< this function will wait until the child finishes or forever if
 110       ///< it doesn't.
 111       unsigned MemoryLimit = 0, ///< If non-zero, this specifies max. amount
 112       ///< of memory can be allocated by process. If memory usage will be
 113       ///< higher limit, the child is killed and this call returns. If zero
 114       ///< - no memory limit.
 115       std::string *ErrMsg = nullptr, ///< If non-zero, provides a pointer to a
 116       ///< string instance in which error messages will be returned. If the
 117       ///< string is non-empty upon return an error occurred while invoking the
 118       ///< program.
 119       bool *ExecutionFailed = nullptr);
 120
 121   /// Similar to ExecuteAndWait, but returns immediately.
 122   /// @returns The \see ProcessInfo of the newly launced process.
 123   /// \note On Microsoft Windows systems, users will need to either call
 124   /// \see Wait until the process finished execution or win32 CloseHandle() API
 125   /// on ProcessInfo.ProcessHandle to avoid memory leaks.
 126   ProcessInfo ExecuteNoWait(StringRef Program, ArrayRef<StringRef> Args,
 127                             Optional<ArrayRef<StringRef>> Env,
 128                             ArrayRef<Optional<StringRef>> Redirects = {},
 129                             unsigned MemoryLimit = 0,
 130                             std::string *ErrMsg = nullptr,
 131                             bool *ExecutionFailed = nullptr);
 132
 133   /// Return true if the given arguments fit within system-specific
 134   /// argument length limits.
 135   bool commandLineFitsWithinSystemLimits(StringRef Program,
 136                                          ArrayRef<StringRef> Args);
 137
 138   /// Return true if the given arguments fit within system-specific
 139   /// argument length limits.
 140   bool commandLineFitsWithinSystemLimits(StringRef Program,
 141                                          ArrayRef<const char *> Args);
 142
 143   /// File encoding options when writing contents that a non-UTF8 tool will
 144   /// read (on Windows systems). For UNIX, we always use UTF-8.
 145   enum WindowsEncodingMethod {
 146     /// UTF-8 is the LLVM native encoding, being the same as "do not perform
 147     /// encoding conversion".
 148     WEM_UTF8,
 149     WEM_CurrentCodePage,
 150     WEM_UTF16
 151   };
 152
 153   /// Saves the UTF8-encoded \p contents string into the file \p FileName
 154   /// using a specific encoding.
 155   ///
 156   /// This write file function adds the possibility to choose which encoding
 157   /// to use when writing a text file. On Windows, this is important when
 158   /// writing files with internationalization support with an encoding that is
 159   /// different from the one used in LLVM (UTF-8). We use this when writing
 160   /// response files, since GCC tools on MinGW only understand legacy code
 161   /// pages, and VisualStudio tools only understand UTF-16.
 162   /// For UNIX, using different encodings is silently ignored, since all tools
 163   /// work well with UTF-8.
 164   /// This function assumes that you only use UTF-8 *text* data and will convert
 165   /// it to your desired encoding before writing to the file.
 166   ///
 167   /// FIXME: We use EM_CurrentCodePage to write response files for GNU tools in
 168   /// a MinGW/MinGW-w64 environment, which has serious flaws but currently is
 169   /// our best shot to make gcc/ld understand international characters. This
 170   /// should be changed as soon as binutils fix this to support UTF16 on mingw.
 171   ///
 172   /// \returns non-zero error_code if failed
 173   std::error_code
 174   writeFileWithEncoding(StringRef FileName, StringRef Contents,
 175                         WindowsEncodingMethod Encoding = WEM_UTF8);
 176
 177   /// This function waits for the process specified by \p PI to finish.
 178   /// \returns A \see ProcessInfo struct with Pid set to:
 179   /// \li The process id of the child process if the child process has changed
 180   /// state.
 181   /// \li 0 if the child process has not changed state.
 182   /// \note Users of this function should always check the ReturnCode member of
 183   /// the \see ProcessInfo returned from this function.
 184   ProcessInfo Wait(
 185       const ProcessInfo &PI, ///< The child process that should be waited on.
 186       unsigned SecondsToWait, ///< If non-zero, this specifies the amount of
 187       ///< time to wait for the child process to exit. If the time expires, the
 188       ///< child is killed and this function returns. If zero, this function
 189       ///< will perform a non-blocking wait on the child process.
 190       bool WaitUntilTerminates, ///< If true, ignores \p SecondsToWait and waits
 191       ///< until child has terminated.
 192       std::string *ErrMsg = nullptr ///< If non-zero, provides a pointer to a
 193       ///< string instance in which error messages will be returned. If the
 194       ///< string is non-empty upon return an error occurred while invoking the
 195       ///< program.
 196       );
 197
 198 #if defined(_WIN32)
 199   /// Given a list of command line arguments, quote and escape them as necessary
 200   /// to build a single flat command line appropriate for calling CreateProcess
 201   /// on
 202   /// Windows.
 203   std::string flattenWindowsCommandLine(ArrayRef<StringRef> Args);
 204 #endif
 205   }
 206 }
 207
 208 #endif