[SystemZ/ZOS] Add header file to encapsulate use of <sysexits.h>

[Kai]

Summary

The non-standard header file <sysexits.h> provides some return values.
EX_IOERR is used to as a special value to signal a broken pipe to the clang driver.
On z/OS Unix System Services, this header file does not exists. This patch

• adds a check for <sysexits.h>, removing the dependency on LLVM_ON_UNIX
• adds a new header file llvm/Support/ExitCodes, which either includes <sysexits.h> or defines EX_IOERR
• updates the users of EX_IOERR to include the new header file

[hubert.reinterpretcast]

llvm/include/llvm/Support/ExitCodes.h

23

Minor nits:
s/exists/exist/;
s/used value/value used/;

[Kai]

Fixed two typos in the comment.

[Kai]

Thank you for pointing out the typo!

[hubert.reinterpretcast]

LGTM from my end.

[mgorny]

llvm/include/llvm/Support/ExitCodes.h

20

This is a private LLVM header and it's not installed. Therefore, this installed header references uninstalled headers and breaks standalone builds of clang. Please use llvm-config.h instead.

clang/lib/Driver/Driver.cpp

 #include "llvm/Config/llvm-config.h"
 #include "llvm/Option/Arg.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Option/OptSpecifier.h"
 #include "llvm/Option/OptTable.h"
 #include "llvm/Option/Option.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/ExitCodes.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/FormatVariadic.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/Program.h"
 #include "llvm/Support/StringSaver.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
 #include <map>
 #include <memory>
 #include <utility>
 #if LLVM_ON_UNIX
 #include <unistd.h> // getpid
-#include <sysexits.h> // EX_IOERR
 #endif
 
 using namespace clang::driver;
 using namespace clang;
 using namespace llvm::opt;
 
 // static
 std::string Driver::GetResourcesPath(StringRef BinaryPath,

llvm/cmake/config-ix.cmake

 check_include_file(signal.h HAVE_SIGNAL_H)
 check_include_file(sys/ioctl.h HAVE_SYS_IOCTL_H)
 check_include_file(sys/mman.h HAVE_SYS_MMAN_H)
 check_include_file(sys/param.h HAVE_SYS_PARAM_H)
 check_include_file(sys/resource.h HAVE_SYS_RESOURCE_H)
 check_include_file(sys/stat.h HAVE_SYS_STAT_H)
 check_include_file(sys/time.h HAVE_SYS_TIME_H)
 check_include_file(sys/types.h HAVE_SYS_TYPES_H)
+check_include_file(sysexits.h HAVE_SYSEXITS_H)
 check_include_file(termios.h HAVE_TERMIOS_H)
 check_include_file(unistd.h HAVE_UNISTD_H)
 check_include_file(valgrind/valgrind.h HAVE_VALGRIND_VALGRIND_H)
 check_include_file(zlib.h HAVE_ZLIB_H)
 check_include_file(fenv.h HAVE_FENV_H)
 check_symbol_exists(FE_ALL_EXCEPT "fenv.h" HAVE_DECL_FE_ALL_EXCEPT)
 check_symbol_exists(FE_INEXACT "fenv.h" HAVE_DECL_FE_INEXACT)
 

llvm/include/llvm/Support/ExitCodes.h

+//===-- llvm/Support/ExitCodes.h - Exit codes for exit()  -------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains definitions of exit codes for exit() function. They are
+/// either defined by sysexits.h if it is supported, or defined here if
+/// sysexits.h is not supported.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_EXITCODES_H
+#define LLVM_SUPPORT_EXITCODES_H
+
+#if HAVE_SYSEXITS_H
+#include <sysexits.h>
+#elif __MVS__
+// <sysexits.h> does not exist on z/OS. The only value used in LLVM is
+// EX_IOERR, which is used to signal a special error condition (broken pipe).
+// Define the macro with its usual value from BSD systems, which is chosen to
+// not clash with more standard exit codes like 1.
+#define EX_IOERR 74
+#elif LLVM_ON_UNIX
+#error Exit code EX_IOERR not available
+#endif
+
+#endif

llvm/lib/Support/CrashRecoveryContext.cpp

 //===--- CrashRecoveryContext.cpp - Crash Recovery ------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/CrashRecoveryContext.h"
 #include "llvm/Config/llvm-config.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/ExitCodes.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/ThreadLocal.h"
 #include <mutex>
 #include <setjmp.h>
-#if LLVM_ON_UNIX
-#include <sysexits.h> // EX_IOERR
-#endif
 
 using namespace llvm;
 
 namespace {
 
 struct CrashRecoveryContextImpl;
 
 static ManagedStatic<

llvm/lib/Support/Unix/Signals.inc

 // being added.
 //
 //===----------------------------------------------------------------------===//
 
 #include "Unix.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Config/config.h"
 #include "llvm/Demangle/Demangle.h"
+#include "llvm/Support/ExitCodes.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/FileUtilities.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Mutex.h"
 #include "llvm/Support/Program.h"
 #include "llvm/Support/SaveAndRestore.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <string>
-#include <sysexits.h>
 #ifdef HAVE_BACKTRACE
 # include BACKTRACE_HEADER         // For backtrace().
 #endif
 #if HAVE_SIGNAL_H
 #include <signal.h>
 #endif
 #if HAVE_SYS_STAT_H
 #include <sys/stat.h>