It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/System/Unix/Path.inc b/lib/System/Unix/Path.inc
new file mode 100644
index 0000000..e4916ba
--- /dev/null
+++ b/lib/System/Unix/Path.inc
@@ -0,0 +1,721 @@
+//===- llvm/System/Unix/Path.cpp - Unix Path Implementation -----*- C++ -*-===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Reid Spencer and is distributed under the 
+// University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// This file implements the Unix specific portion of the Path class.
+//
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+//=== WARNING: Implementation here must contain only generic UNIX code that
+//===          is guaranteed to work on *all* UNIX variants.
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Config/alloca.h"
+#include "Unix.h"
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#if HAVE_FCNTL_H
+#include <fcntl.h>
+#endif
+#if HAVE_UTIME_H
+#include <utime.h>
+#endif
+#if HAVE_TIME_H
+#include <time.h>
+#endif
+#if HAVE_DIRENT_H
+# include <dirent.h>
+# define NAMLEN(dirent) strlen((dirent)->d_name)
+#else
+# define dirent direct
+# define NAMLEN(dirent) (dirent)->d_namlen
+# if HAVE_SYS_NDIR_H
+#  include <sys/ndir.h>
+# endif
+# if HAVE_SYS_DIR_H
+#  include <sys/dir.h>
+# endif
+# if HAVE_NDIR_H
+#  include <ndir.h>
+# endif
+#endif
+
+// Put in a hack for Cygwin which falsely reports that the mkdtemp function
+// is available when it is not.
+#ifdef __CYGWIN__
+# undef HAVE_MKDTEMP
+#endif
+
+namespace {
+inline bool lastIsSlash(const std::string& path) {
+  return !path.empty() && path[path.length() - 1] == '/';
+}
+
+}
+
+namespace llvm {
+using namespace sys;
+
+bool 
+Path::isValid() const {
+  // Check some obvious things
+  if (path.empty()) 
+    return false;
+  else if (path.length() >= MAXPATHLEN)
+    return false;
+
+  // Check that the characters are ascii chars
+  size_t len = path.length();
+  unsigned i = 0;
+  while (i < len && isascii(path[i])) 
+    ++i;
+  return i >= len; 
+}
+
+bool 
+Path::isAbsolute() const {
+  if (path.empty())
+    return false;
+  return path[0] == '/';
+} 
+Path
+Path::GetRootDirectory() {
+  Path result;
+  result.set("/");
+  return result;
+}
+
+Path
+Path::GetTemporaryDirectory(std::string* ErrMsg ) {
+#if defined(HAVE_MKDTEMP)
+  // The best way is with mkdtemp but that's not available on many systems, 
+  // Linux and FreeBSD have it. Others probably won't.
+  char pathname[MAXPATHLEN];
+  strcpy(pathname,"/tmp/llvm_XXXXXX");
+  if (0 == mkdtemp(pathname)) {
+    MakeErrMsg(ErrMsg, 
+      std::string(pathname) + ": can't create temporary directory");
+    return Path();
+  }
+  Path result;
+  result.set(pathname);
+  assert(result.isValid() && "mkdtemp didn't create a valid pathname!");
+  return result;
+#elif defined(HAVE_MKSTEMP)
+  // If no mkdtemp is available, mkstemp can be used to create a temporary file
+  // which is then removed and created as a directory. We prefer this over
+  // mktemp because of mktemp's inherent security and threading risks. We still
+  // have a slight race condition from the time the temporary file is created to
+  // the time it is re-created as a directoy. 
+  char pathname[MAXPATHLEN];
+  strcpy(pathname, "/tmp/llvm_XXXXXX");
+  int fd = 0;
+  if (-1 == (fd = mkstemp(pathname))) {
+    MakeErrMsg(ErrMsg, 
+      std::string(pathname) + ": can't create temporary directory");
+    return Path();
+  }
+  ::close(fd);
+  ::unlink(pathname); // start race condition, ignore errors
+  if (-1 == ::mkdir(pathname, S_IRWXU)) { // end race condition
+    MakeErrMsg(ErrMsg, 
+      std::string(pathname) + ": can't create temporary directory");
+    return Path();
+  }
+  Path result;
+  result.set(pathname);
+  assert(result.isValid() && "mkstemp didn't create a valid pathname!");
+  return result;
+#elif defined(HAVE_MKTEMP)
+  // If a system doesn't have mkdtemp(3) or mkstemp(3) but it does have
+  // mktemp(3) then we'll assume that system (e.g. AIX) has a reasonable
+  // implementation of mktemp(3) and doesn't follow BSD 4.3's lead of replacing
+  // the XXXXXX with the pid of the process and a letter. That leads to only
+  // twenty six temporary files that can be generated.
+  char pathname[MAXPATHLEN];
+  strcpy(pathname, "/tmp/llvm_XXXXXX");
+  char *TmpName = ::mktemp(pathname);
+  if (TmpName == 0) {
+    MakeErrMsg(ErrMsg, 
+      std::string(TmpName) + ": can't create unique directory name");
+    return Path();
+  }
+  if (-1 == ::mkdir(TmpName, S_IRWXU)) {
+    MakeErrMsg(ErrMsg, 
+        std::string(TmpName) + ": can't create temporary directory");
+    return Path();
+  }
+  Path result;
+  result.set(TmpName);
+  assert(result.isValid() && "mktemp didn't create a valid pathname!");
+  return result;
+#else
+  // This is the worst case implementation. tempnam(3) leaks memory unless its
+  // on an SVID2 (or later) system. On BSD 4.3 it leaks. tmpnam(3) has thread
+  // issues. The mktemp(3) function doesn't have enough variability in the
+  // temporary name generated. So, we provide our own implementation that 
+  // increments an integer from a random number seeded by the current time. This
+  // should be sufficiently unique that we don't have many collisions between
+  // processes. Generally LLVM processes don't run very long and don't use very
+  // many temporary files so this shouldn't be a big issue for LLVM.
+  static time_t num = ::time(0);
+  char pathname[MAXPATHLEN];
+  do {
+    num++;
+    sprintf(pathname, "/tmp/llvm_%010u", unsigned(num));
+  } while ( 0 == access(pathname, F_OK ) );
+  if (-1 == ::mkdir(pathname, S_IRWXU)) {
+    MakeErrMsg(ErrMsg, 
+      std::string(pathname) + ": can't create temporary directory");
+    return Path();
+  }
+  Path result;
+  result.set(pathname);
+  assert(result.isValid() && "mkstemp didn't create a valid pathname!");
+  return result;
+#endif
+}
+
+static void getPathList(const char*path, std::vector<sys::Path>& Paths) {
+  const char* at = path;
+  const char* delim = strchr(at, ':');
+  Path tmpPath;
+  while( delim != 0 ) {
+    std::string tmp(at, size_t(delim-at));
+    if (tmpPath.set(tmp))
+      if (tmpPath.canRead())
+        Paths.push_back(tmpPath);
+    at = delim + 1;
+    delim = strchr(at, ':');
+  }
+  if (*at != 0)
+    if (tmpPath.set(std::string(at)))
+      if (tmpPath.canRead())
+        Paths.push_back(tmpPath);
+
+}
+
+void 
+Path::GetSystemLibraryPaths(std::vector<sys::Path>& Paths) {
+#ifdef LTDL_SHLIBPATH_VAR
+  char* env_var = getenv(LTDL_SHLIBPATH_VAR);
+  if (env_var != 0) {
+    getPathList(env_var,Paths);
+  }
+#endif
+  // FIXME: Should this look at LD_LIBRARY_PATH too?
+  Paths.push_back(sys::Path("/usr/local/lib/"));
+  Paths.push_back(sys::Path("/usr/X11R6/lib/"));
+  Paths.push_back(sys::Path("/usr/lib/"));
+  Paths.push_back(sys::Path("/lib/"));
+}
+
+void
+Path::GetBitcodeLibraryPaths(std::vector<sys::Path>& Paths) {
+  char * env_var = getenv("LLVM_LIB_SEARCH_PATH");
+  if (env_var != 0) {
+    getPathList(env_var,Paths);
+  }
+#ifdef LLVM_LIBDIR
+  {
+    Path tmpPath;
+    if (tmpPath.set(LLVM_LIBDIR))
+      if (tmpPath.canRead())
+        Paths.push_back(tmpPath);
+  }
+#endif
+  GetSystemLibraryPaths(Paths);
+}
+
+Path 
+Path::GetLLVMDefaultConfigDir() {
+  return Path("/etc/llvm/");
+}
+
+Path
+Path::GetUserHomeDirectory() {
+  const char* home = getenv("HOME");
+  if (home) {
+    Path result;
+    if (result.set(home))
+      return result;
+  }
+  return GetRootDirectory();
+}
+
+
+std::string
+Path::getBasename() const {
+  // Find the last slash
+  size_t slash = path.rfind('/');
+  if (slash == std::string::npos)
+    slash = 0;
+  else
+    slash++;
+
+  size_t dot = path.rfind('.');
+  if (dot == std::string::npos || dot < slash)
+    return path.substr(slash);
+  else
+    return path.substr(slash, dot - slash);
+}
+
+bool Path::getMagicNumber(std::string& Magic, unsigned len) const {
+  assert(len < 1024 && "Request for magic string too long");
+  char* buf = (char*) alloca(1 + len);
+  int fd = ::open(path.c_str(), O_RDONLY);
+  if (fd < 0)
+    return false;
+  ssize_t bytes_read = ::read(fd, buf, len);
+  ::close(fd);
+  if (ssize_t(len) != bytes_read) {
+    Magic.clear();
+    return false;
+  }
+  Magic.assign(buf,len);
+  return true;
+}
+
+bool
+Path::exists() const {
+  return 0 == access(path.c_str(), F_OK );
+}
+
+bool
+Path::canRead() const {
+  return 0 == access(path.c_str(), F_OK | R_OK );
+}
+
+bool
+Path::canWrite() const {
+  return 0 == access(path.c_str(), F_OK | W_OK );
+}
+
+bool
+Path::canExecute() const {
+  if (0 != access(path.c_str(), R_OK | X_OK ))
+    return false;
+  struct stat buf;
+  if (0 != stat(path.c_str(), &buf))
+    return false;
+  if (!S_ISREG(buf.st_mode))
+    return false;
+  return true;
+}
+
+std::string 
+Path::getLast() const {
+  // Find the last slash
+  size_t pos = path.rfind('/');
+
+  // Handle the corner cases
+  if (pos == std::string::npos)
+    return path;
+
+  // If the last character is a slash
+  if (pos == path.length()-1) {
+    // Find the second to last slash
+    size_t pos2 = path.rfind('/', pos-1);
+    if (pos2 == std::string::npos)
+      return path.substr(0,pos);
+    else
+      return path.substr(pos2+1,pos-pos2-1);
+  }
+  // Return everything after the last slash
+  return path.substr(pos+1);
+}
+
+const FileStatus *
+PathWithStatus::getFileStatus(bool update, std::string *ErrStr) const {
+  if (!fsIsValid || update) {
+    struct stat buf;
+    if (0 != stat(path.c_str(), &buf)) {
+      MakeErrMsg(ErrStr, path + ": can't get status of file");
+      return 0;
+    }
+    status.fileSize = buf.st_size;
+    status.modTime.fromEpochTime(buf.st_mtime);
+    status.mode = buf.st_mode;
+    status.user = buf.st_uid;
+    status.group = buf.st_gid;
+    status.uniqueID = uint64_t(buf.st_ino);
+    status.isDir  = S_ISDIR(buf.st_mode);
+    status.isFile = S_ISREG(buf.st_mode);
+    fsIsValid = true;
+  }
+  return &status;
+}
+
+static bool AddPermissionBits(const Path &File, int bits) {
+  // Get the umask value from the operating system.  We want to use it
+  // when changing the file's permissions. Since calling umask() sets
+  // the umask and returns its old value, we must call it a second
+  // time to reset it to the user's preference.
+  int mask = umask(0777); // The arg. to umask is arbitrary.
+  umask(mask);            // Restore the umask.
+
+  // Get the file's current mode.
+  struct stat buf;
+  if (0 != stat(File.toString().c_str(), &buf)) 
+    return false;
+  // Change the file to have whichever permissions bits from 'bits'
+  // that the umask would not disable.
+  if ((chmod(File.c_str(), (buf.st_mode | (bits & ~mask)))) == -1)
+      return false;
+  return true;
+}
+
+bool Path::makeReadableOnDisk(std::string* ErrMsg) {
+  if (!AddPermissionBits(*this, 0444)) 
+    return MakeErrMsg(ErrMsg, path + ": can't make file readable");
+  return false;
+}
+
+bool Path::makeWriteableOnDisk(std::string* ErrMsg) {
+  if (!AddPermissionBits(*this, 0222))
+    return MakeErrMsg(ErrMsg, path + ": can't make file writable");
+  return false;
+}
+
+bool Path::makeExecutableOnDisk(std::string* ErrMsg) {
+  if (!AddPermissionBits(*this, 0111))
+    return MakeErrMsg(ErrMsg, path + ": can't make file executable");
+  return false;
+}
+
+bool
+Path::getDirectoryContents(std::set<Path>& result, std::string* ErrMsg) const {
+  DIR* direntries = ::opendir(path.c_str());
+  if (direntries == 0)
+    return MakeErrMsg(ErrMsg, path + ": can't open directory");
+
+  std::string dirPath = path;
+  if (!lastIsSlash(dirPath))
+    dirPath += '/';
+
+  result.clear();
+  struct dirent* de = ::readdir(direntries);
+  for ( ; de != 0; de = ::readdir(direntries)) {
+    if (de->d_name[0] != '.') {
+      Path aPath(dirPath + (const char*)de->d_name);
+      struct stat st;
+      if (0 != lstat(aPath.path.c_str(), &st)) {
+        if (S_ISLNK(st.st_mode))
+          continue; // dangling symlink -- ignore
+        return MakeErrMsg(ErrMsg, 
+                          aPath.path +  ": can't determine file object type");
+      }
+      result.insert(aPath);
+    }
+  }
+  
+  closedir(direntries);
+  return false;
+}
+
+bool
+Path::set(const std::string& a_path) {
+  if (a_path.empty())
+    return false;
+  std::string save(path);
+  path = a_path;
+  if (!isValid()) {
+    path = save;
+    return false;
+  }
+  return true;
+}
+
+bool
+Path::appendComponent(const std::string& name) {
+  if (name.empty())
+    return false;
+  std::string save(path);
+  if (!lastIsSlash(path))
+    path += '/';
+  path += name;
+  if (!isValid()) {
+    path = save;
+    return false;
+  }
+  return true;
+}
+
+bool
+Path::eraseComponent() {
+  size_t slashpos = path.rfind('/',path.size());
+  if (slashpos == 0 || slashpos == std::string::npos) {
+    path.erase();
+    return true;
+  }
+  if (slashpos == path.size() - 1)
+    slashpos = path.rfind('/',slashpos-1);
+  if (slashpos == std::string::npos) {
+    path.erase();
+    return true;
+  }
+  path.erase(slashpos);
+  return true;
+}
+
+bool
+Path::appendSuffix(const std::string& suffix) {
+  std::string save(path);
+  path.append(".");
+  path.append(suffix);
+  if (!isValid()) {
+    path = save;
+    return false;
+  }
+  return true;
+}
+
+bool
+Path::eraseSuffix() {
+  std::string save = path;
+  size_t dotpos = path.rfind('.',path.size());
+  size_t slashpos = path.rfind('/',path.size());
+  if (dotpos != std::string::npos) {
+    if (slashpos == std::string::npos || dotpos > slashpos+1) {
+      path.erase(dotpos, path.size()-dotpos);
+      return true;
+    }
+  }
+  if (!isValid())
+    path = save;
+  return false;
+}
+
+bool
+Path::createDirectoryOnDisk( bool create_parents, std::string* ErrMsg ) {
+  // Get a writeable copy of the path name
+  char pathname[MAXPATHLEN];
+  path.copy(pathname,MAXPATHLEN);
+
+  // Null-terminate the last component
+  int lastchar = path.length() - 1 ; 
+  if (pathname[lastchar] == '/') 
+    pathname[lastchar] = 0;
+  else 
+    pathname[lastchar+1] = 0;
+
+  // If we're supposed to create intermediate directories
+  if ( create_parents ) {
+    // Find the end of the initial name component
+    char * next = strchr(pathname,'/');
+    if ( pathname[0] == '/') 
+      next = strchr(&pathname[1],'/');
+
+    // Loop through the directory components until we're done 
+    while ( next != 0 ) {
+      *next = 0;
+      if (0 != access(pathname, F_OK | R_OK | W_OK))
+        if (0 != mkdir(pathname, S_IRWXU | S_IRWXG)) {
+          return MakeErrMsg(ErrMsg, 
+                            std::string(pathname) + ": can't create directory");
+        }
+      char* save = next;
+      next = strchr(next+1,'/');
+      *save = '/';
+    }
+  } 
+
+  if (0 != access(pathname, F_OK | R_OK))
+    if (0 != mkdir(pathname, S_IRWXU | S_IRWXG)) {
+      return MakeErrMsg(ErrMsg, 
+                        std::string(pathname) + ": can't create directory");
+    }
+  return false;
+}
+
+bool
+Path::createFileOnDisk(std::string* ErrMsg) {
+  // Create the file
+  int fd = ::creat(path.c_str(), S_IRUSR | S_IWUSR);
+  if (fd < 0)
+    return MakeErrMsg(ErrMsg, path + ": can't create file");
+  ::close(fd);
+  return false;
+}
+
+bool
+Path::createTemporaryFileOnDisk(bool reuse_current, std::string* ErrMsg) {
+  // Make this into a unique file name
+  if (makeUnique( reuse_current, ErrMsg ))
+    return true;
+
+  // create the file
+  int fd = ::open(path.c_str(), O_WRONLY|O_CREAT|O_TRUNC, 0666);
+  if (fd < 0) 
+    return MakeErrMsg(ErrMsg, path + ": can't create temporary file");
+  ::close(fd);
+  return false;
+}
+
+bool
+Path::eraseFromDisk(bool remove_contents, std::string *ErrStr) const {
+  // Get the status so we can determin if its a file or directory
+  struct stat buf;
+  if (0 != stat(path.c_str(), &buf)) {
+    MakeErrMsg(ErrStr, path + ": can't get status of file");
+    return true;
+  }
+
+  // Note: this check catches strange situations. In all cases, LLVM should 
+  // only be involved in the creation and deletion of regular files.  This 
+  // check ensures that what we're trying to erase is a regular file. It 
+  // effectively prevents LLVM from erasing things like /dev/null, any block 
+  // special file, or other things that aren't "regular" files. 
+  if (S_ISREG(buf.st_mode)) {
+    if (unlink(path.c_str()) != 0)
+      return MakeErrMsg(ErrStr, path + ": can't destroy file");
+    return false;
+  }
+  
+  if (!S_ISDIR(buf.st_mode)) {
+    if (ErrStr) *ErrStr = "not a file or directory";
+    return true;
+  }
+
+  if (remove_contents) {
+    // Recursively descend the directory to remove its contents.
+    std::string cmd = "/bin/rm -rf " + path;
+    system(cmd.c_str());
+    return false;
+  }
+
+  // Otherwise, try to just remove the one directory.
+  char pathname[MAXPATHLEN];
+  path.copy(pathname, MAXPATHLEN);
+  int lastchar = path.length() - 1 ; 
+  if (pathname[lastchar] == '/') 
+    pathname[lastchar] = 0;
+  else
+    pathname[lastchar+1] = 0;
+    
+  if (rmdir(pathname) != 0)
+    return MakeErrMsg(ErrStr, 
+      std::string(pathname) + ": can't erase directory");
+  return false;
+}
+
+bool
+Path::renamePathOnDisk(const Path& newName, std::string* ErrMsg) {
+  if (0 != ::rename(path.c_str(), newName.c_str()))
+    return MakeErrMsg(ErrMsg, std::string("can't rename '") + path + "' as '" + 
+               newName.toString() + "' ");
+  return false;
+}
+
+bool 
+Path::setStatusInfoOnDisk(const FileStatus &si, std::string *ErrStr) const {
+  struct utimbuf utb;
+  utb.actime = si.modTime.toPosixTime();
+  utb.modtime = utb.actime;
+  if (0 != ::utime(path.c_str(),&utb))
+    return MakeErrMsg(ErrStr, path + ": can't set file modification time");
+  if (0 != ::chmod(path.c_str(),si.mode))
+    return MakeErrMsg(ErrStr, path + ": can't set mode");
+  return false;
+}
+
+bool 
+sys::CopyFile(const sys::Path &Dest, const sys::Path &Src, std::string* ErrMsg){
+  int inFile = -1;
+  int outFile = -1;
+  inFile = ::open(Src.c_str(), O_RDONLY);
+  if (inFile == -1)
+    return MakeErrMsg(ErrMsg, Src.toString() + 
+      ": can't open source file to copy");
+
+  outFile = ::open(Dest.c_str(), O_WRONLY|O_CREAT, 0666);
+  if (outFile == -1) {
+    ::close(inFile);
+    return MakeErrMsg(ErrMsg, Dest.toString() +
+      ": can't create destination file for copy");
+  }
+
+  char Buffer[16*1024];
+  while (ssize_t Amt = ::read(inFile, Buffer, 16*1024)) {
+    if (Amt == -1) {
+      if (errno != EINTR && errno != EAGAIN) {
+        ::close(inFile);
+        ::close(outFile);
+        return MakeErrMsg(ErrMsg, Src.toString()+": can't read source file: ");
+      }
+    } else {
+      char *BufPtr = Buffer;
+      while (Amt) {
+        ssize_t AmtWritten = ::write(outFile, BufPtr, Amt);
+        if (AmtWritten == -1) {
+          if (errno != EINTR && errno != EAGAIN) {
+            ::close(inFile);
+            ::close(outFile);
+            return MakeErrMsg(ErrMsg, Dest.toString() + 
+              ": can't write destination file: ");
+          }
+        } else {
+          Amt -= AmtWritten;
+          BufPtr += AmtWritten;
+        }
+      }
+    }
+  }
+  ::close(inFile);
+  ::close(outFile);
+  return false;
+}
+
+bool 
+Path::makeUnique(bool reuse_current, std::string* ErrMsg) {
+  if (reuse_current && !exists())
+    return false; // File doesn't exist already, just use it!
+
+  // Append an XXXXXX pattern to the end of the file for use with mkstemp, 
+  // mktemp or our own implementation.
+  char *FNBuffer = (char*) alloca(path.size()+8);
+  path.copy(FNBuffer,path.size());
+  strcpy(FNBuffer+path.size(), "-XXXXXX");
+
+#if defined(HAVE_MKSTEMP)
+  int TempFD;
+  if ((TempFD = mkstemp(FNBuffer)) == -1)
+    return MakeErrMsg(ErrMsg, path + ": can't make unique filename");
+
+  // We don't need to hold the temp file descriptor... we will trust that no one
+  // will overwrite/delete the file before we can open it again.
+  close(TempFD);
+
+  // Save the name
+  path = FNBuffer;
+#elif defined(HAVE_MKTEMP)
+  // If we don't have mkstemp, use the old and obsolete mktemp function.
+  if (mktemp(FNBuffer) == 0)
+    return MakeErrMsg(ErrMsg, path + ": can't make unique filename");
+
+  // Save the name
+  path = FNBuffer;
+#else
+  // Okay, looks like we have to do it all by our lonesome.
+  static unsigned FCounter = 0;
+  unsigned offset = path.size() + 1;
+  while ( FCounter < 999999 && exists()) {
+    sprintf(FNBuffer+offset,"%06u",++FCounter);
+    path = FNBuffer;
+  }
+  if (FCounter > 999999)
+    return MakeErrMsg(ErrMsg, 
+      path + ": can't make unique filename: too many files");
+#endif
+  return false;
+}
+
+} // end llvm namespace
+