LLVM  3.7.0
Program.h
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1 //===- llvm/Support/Program.h ------------------------------------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file declares the llvm::sys::Program class.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_SUPPORT_PROGRAM_H
15 #define LLVM_SUPPORT_PROGRAM_H
16 
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/Support/ErrorOr.h"
19 #include <system_error>
20 
21 namespace llvm {
22 class StringRef;
23 
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 (LLVM_ON_WIN32)
31  const char EnvPathSeparator = ';';
32 #endif
33 
34 /// @brief This struct encapsulates information about a process.
35 struct ProcessInfo {
36 #if defined(LLVM_ON_UNIX)
37  typedef pid_t ProcessId;
38 #elif defined(LLVM_ON_WIN32)
39  typedef unsigned long ProcessId; // Must match the type of DWORD on Windows.
40  typedef void * HANDLE; // Must match the type of HANDLE on Windows.
41  /// The handle to the process (available on Windows only).
42  HANDLE ProcessHandle;
43 #else
44 #error "ProcessInfo is not defined for this platform!"
45 #endif
46 
47  /// The process identifier.
48  ProcessId Pid;
49 
50  /// The return code, set after execution.
52 
53  ProcessInfo();
54 };
55 
56  /// \brief Find the first executable file \p Name in \p Paths.
57  ///
58  /// This does not perform hashing as a shell would but instead stats each PATH
59  /// entry individually so should generally be avoided. Core LLVM library
60  /// functions and options should instead require fully specified paths.
61  ///
62  /// \param Name name of the executable to find. If it contains any system
63  /// slashes, it will be returned as is.
64  /// \param Paths optional list of paths to search for \p Name. If empty it
65  /// will use the system PATH environment instead.
66  ///
67  /// \returns The fully qualified path to the first \p Name in \p Paths if it
68  /// exists. \p Name if \p Name has slashes in it. Otherwise an error.
72 
73  // These functions change the specified standard stream (stdin or stdout) to
74  // binary mode. They return errc::success if the specified stream
75  // was changed. Otherwise a platform dependent error is returned.
76  std::error_code ChangeStdinToBinary();
77  std::error_code ChangeStdoutToBinary();
78 
79  /// This function executes the program using the arguments provided. The
80  /// invoked program will inherit the stdin, stdout, and stderr file
81  /// descriptors, the environment and other configuration settings of the
82  /// invoking program.
83  /// This function waits for the program to finish, so should be avoided in
84  /// library functions that aren't expected to block. Consider using
85  /// ExecuteNoWait() instead.
86  /// @returns an integer result code indicating the status of the program.
87  /// A zero or positive value indicates the result code of the program.
88  /// -1 indicates failure to execute
89  /// -2 indicates a crash during execution or timeout
90  int ExecuteAndWait(
91  StringRef Program, ///< Path of the program to be executed. It is
92  /// presumed this is the result of the findProgramByName method.
93  const char **args, ///< A vector of strings that are passed to the
94  ///< program. The first element should be the name of the program.
95  ///< The list *must* be terminated by a null char* entry.
96  const char **env = nullptr, ///< An optional vector of strings to use for
97  ///< the program's environment. If not provided, the current program's
98  ///< environment will be used.
99  const StringRef **redirects = nullptr, ///< An optional array of pointers
100  ///< to paths. If the array is null, no redirection is done. The array
101  ///< should have a size of at least three. The inferior process's
102  ///< stdin(0), stdout(1), and stderr(2) will be redirected to the
103  ///< corresponding paths.
104  ///< When an empty path is passed in, the corresponding file
105  ///< descriptor will be disconnected (ie, /dev/null'd) in a portable
106  ///< way.
107  unsigned secondsToWait = 0, ///< If non-zero, this specifies the amount
108  ///< of time to wait for the child process to exit. If the time
109  ///< expires, the child is killed and this call returns. If zero,
110  ///< this function will wait until the child finishes or forever if
111  ///< it doesn't.
112  unsigned memoryLimit = 0, ///< If non-zero, this specifies max. amount
113  ///< of memory can be allocated by process. If memory usage will be
114  ///< higher limit, the child is killed and this call returns. If zero
115  ///< - no memory limit.
116  std::string *ErrMsg = nullptr, ///< If non-zero, provides a pointer to a
117  ///< string instance in which error messages will be returned. If the
118  ///< string is non-empty upon return an error occurred while invoking the
119  ///< program.
120  bool *ExecutionFailed = nullptr);
121 
122  /// Similar to ExecuteAndWait, but returns immediately.
123  /// @returns The \see ProcessInfo of the newly launced process.
124  /// \note On Microsoft Windows systems, users will need to either call \see
125  /// Wait until the process finished execution or win32 CloseHandle() API on
126  /// ProcessInfo.ProcessHandle to avoid memory leaks.
128  ExecuteNoWait(StringRef Program, const char **args, const char **env = nullptr,
129  const StringRef **redirects = nullptr, unsigned memoryLimit = 0,
130  std::string *ErrMsg = nullptr, bool *ExecutionFailed = nullptr);
131 
132  /// Return true if the given arguments fit within system-specific
133  /// argument length limits.
135 
136  /// File encoding options when writing contents that a non-UTF8 tool will
137  /// read (on Windows systems). For UNIX, we always use UTF-8.
139  /// UTF-8 is the LLVM native encoding, being the same as "do not perform
140  /// encoding conversion".
144  };
145 
146  /// Saves the UTF8-encoded \p contents string into the file \p FileName
147  /// using a specific encoding.
148  ///
149  /// This write file function adds the possibility to choose which encoding
150  /// to use when writing a text file. On Windows, this is important when
151  /// writing files with internationalization support with an encoding that is
152  /// different from the one used in LLVM (UTF-8). We use this when writing
153  /// response files, since GCC tools on MinGW only understand legacy code
154  /// pages, and VisualStudio tools only understand UTF-16.
155  /// For UNIX, using different encodings is silently ignored, since all tools
156  /// work well with UTF-8.
157  /// This function assumes that you only use UTF-8 *text* data and will convert
158  /// it to your desired encoding before writing to the file.
159  ///
160  /// FIXME: We use EM_CurrentCodePage to write response files for GNU tools in
161  /// a MinGW/MinGW-w64 environment, which has serious flaws but currently is
162  /// our best shot to make gcc/ld understand international characters. This
163  /// should be changed as soon as binutils fix this to support UTF16 on mingw.
164  ///
165  /// \returns non-zero error_code if failed
166  std::error_code
167  writeFileWithEncoding(StringRef FileName, StringRef Contents,
168  WindowsEncodingMethod Encoding = WEM_UTF8);
169 
170  /// This function waits for the process specified by \p PI to finish.
171  /// \returns A \see ProcessInfo struct with Pid set to:
172  /// \li The process id of the child process if the child process has changed
173  /// state.
174  /// \li 0 if the child process has not changed state.
175  /// \note Users of this function should always check the ReturnCode member of
176  /// the \see ProcessInfo returned from this function.
178  const ProcessInfo &PI, ///< The child process that should be waited on.
179  unsigned SecondsToWait, ///< If non-zero, this specifies the amount of
180  ///< time to wait for the child process to exit. If the time expires, the
181  ///< child is killed and this function returns. If zero, this function
182  ///< will perform a non-blocking wait on the child process.
183  bool WaitUntilTerminates, ///< If true, ignores \p SecondsToWait and waits
184  ///< until child has terminated.
185  std::string *ErrMsg = nullptr ///< If non-zero, provides a pointer to a
186  ///< string instance in which error messages will be returned. If the
187  ///< string is non-empty upon return an error occurred while invoking the
188  ///< program.
189  );
190  }
191 }
192 
193 #endif
Represents either an error or a value T.
Definition: ErrorOr.h:82
std::error_code ChangeStdoutToBinary()
UTF-8 is the LLVM native encoding, being the same as "do not perform encoding conversion"...
Definition: Program.h:141
ProcessInfo ExecuteNoWait(StringRef Program, const char **args, const char **env=nullptr, const StringRef **redirects=nullptr, unsigned memoryLimit=0, std::string *ErrMsg=nullptr, bool *ExecutionFailed=nullptr)
Similar to ExecuteAndWait, but returns immediately.
Definition: Program.cpp:49
bool argumentsFitWithinSystemLimits(ArrayRef< const char * > Args)
Return true if the given arguments fit within system-specific argument length limits.
ErrorOr< std::string > findProgramByName(StringRef Name, ArrayRef< StringRef > Paths=ArrayRef< StringRef >())
Find the first executable file Name in Paths.
ProcessId Pid
The process identifier.
Definition: Program.h:48
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory)...
Definition: ArrayRef.h:31
int ExecuteAndWait(StringRef Program, const char **args, const char **env=nullptr, const StringRef **redirects=nullptr, unsigned secondsToWait=0, unsigned memoryLimit=0, std::string *ErrMsg=nullptr, bool *ExecutionFailed=nullptr)
This function executes the program using the arguments provided.
Definition: Program.cpp:30
std::error_code writeFileWithEncoding(StringRef FileName, StringRef Contents, WindowsEncodingMethod Encoding=WEM_UTF8)
Saves the UTF8-encoded contents string into the file FileName using a specific encoding.
WindowsEncodingMethod
File encoding options when writing contents that a non-UTF8 tool will read (on Windows systems)...
Definition: Program.h:138
int ReturnCode
The return code, set after execution.
Definition: Program.h:51
std::error_code ChangeStdinToBinary()
This is the OS-specific separator for PATH like environment variables:
Definition: Program.h:35
Provides ErrorOr<T> smart pointer.
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:40
ProcessInfo Wait(const ProcessInfo &PI, unsigned SecondsToWait, bool WaitUntilTerminates, std::string *ErrMsg=nullptr)
This function waits for the process specified by PI to finish.