Initial checkin of c-language parser

llvm-svn: 38539

1 files changed, 136 insertions, 0 deletions

diff --git a/clang/Basic/FileManager.cpp b/clang/Basic/FileManager.cpp
new file mode 100644
index 00000000000..7044a70465f
--- /dev/null
+++ b/clang/Basic/FileManager.cpp
@@ -0,0 +1,136 @@
+//===--- FileManager.cpp - File System Probing and Caching ----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Chris Lattner and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements the FileManager interface.
+//
+//===----------------------------------------------------------------------===//
+//
+// TODO: This should index all interesting directories with dirent calls.
+//  getdirentries ?
+//  opendir/readdir_r/closedir ?
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Basic/FileManager.h"
+#include <iostream>
+using namespace llvm;
+using namespace clang;
+
+// FIXME: Enhance libsystem to support inode and other fields.
+#include <sys/stat.h>
+
+/// getDirectory - Lookup, cache, and verify the specified directory.  This
+/// returns null if the directory doesn't exist.
+/// 
+const DirectoryEntry *FileManager::getDirectory(const std::string &Filename) {
+  ++NumDirLookups;
+  // See if there is already an entry in the map.
+  std::map<std::string, DirectoryEntry*>::iterator I = 
+    DirEntries.lower_bound(Filename);
+  if (I != DirEntries.end() && I->first == Filename)
+    return I->second;
+  
+  ++NumDirCacheMisses;
+  
+  // By default, zero initialize it.
+  DirectoryEntry *&Ent =
+    DirEntries.insert(I, std::make_pair(Filename, (DirectoryEntry*)0))->second;
+  
+  // Nope, there isn't.  Check to see if the directory exists.
+  struct stat StatBuf;
+  if (stat(Filename.c_str(), &StatBuf) ||   // Error stat'ing.
+      !S_ISDIR(StatBuf.st_mode))            // Not a directory?
+    return 0;
+  
+  // It exists.  See if we have already opened a directory with the same inode.
+  // This occurs when one dir is symlinked to another, for example.
+  DirectoryEntry *&UDE = 
+    UniqueDirs[std::make_pair(StatBuf.st_dev, StatBuf.st_ino)];
+  
+  if (UDE)  // Already have an entry with this inode, return it.
+    return Ent = UDE;
+  
+  // Otherwise, we don't have this directory yet, add it.
+  DirectoryEntry *DE = new DirectoryEntry();
+  DE->Name           = Filename;
+  return Ent = UDE = DE;
+}
+
+/// getFile - Lookup, cache, and verify the specified file.  This returns null
+/// if the file doesn't exist.
+/// 
+const FileEntry *FileManager::getFile(const std::string &Filename) {
+  ++NumFileLookups;
+  
+  // See if there is already an entry in the map.
+  std::map<std::string, FileEntry*>::iterator I = 
+    FileEntries.lower_bound(Filename);
+  if (I != FileEntries.end() && I->first == Filename)
+    return I->second;
+
+  ++NumFileCacheMisses;
+
+  // By default, zero initialize it.
+  FileEntry *&Ent =
+    FileEntries.insert(I, std::make_pair(Filename, (FileEntry*)0))->second;
+
+  // Figure out what directory it is in.
+  std::string DirName;
+  
+  // If the string contains a / in it, strip off everything after it.
+  // FIXME: this logic should be in sys::Path.
+  std::string::size_type SlashPos = Filename.find_last_of('/');
+  if (SlashPos == std::string::npos)
+    DirName = ".";  // Use the current directory if file has no path component.
+  else if (SlashPos == Filename.size()-1)
+    return 0;       // If filename ends with a /, it's a directory.
+  else
+    DirName = std::string(Filename.begin(), Filename.begin()+SlashPos);
+
+  const DirectoryEntry *DirInfo = getDirectory(DirName);
+  if (DirInfo == 0)  // Directory doesn't exist, file can't exist.
+    return 0;
+  
+  // FIXME: Use the directory info to prune this, before doing the stat syscall.
+  // FIXME: This will reduce the # syscalls.
+  
+  // Nope, there isn't.  Check to see if the file exists.
+  struct stat StatBuf;
+  if (stat(Filename.c_str(), &StatBuf) ||   // Error stat'ing.
+      S_ISDIR(StatBuf.st_mode))             // A directory?
+    return 0;
+  
+  // It exists.  See if we have already opened a directory with the same inode.
+  // This occurs when one dir is symlinked to another, for example.
+  FileEntry *&UFE = 
+    UniqueFiles[std::make_pair(StatBuf.st_dev, StatBuf.st_ino)];
+  
+  if (UFE)  // Already have an entry with this inode, return it.
+    return Ent = UFE;
+  
+  // Otherwise, we don't have this directory yet, add it.
+  FileEntry *FE = new FileEntry();
+  FE->Size      = StatBuf.st_size;
+  FE->Name      = Filename;
+  FE->Dir       = DirInfo;
+  FE->UID       = NextFileUID++;
+  return Ent = UFE = FE;
+}
+
+void FileManager::PrintStats() const {
+  std::cerr << "\n*** File Manager Stats:\n";
+  std::cerr << UniqueFiles.size() << " files found, "
+            << UniqueDirs.size() << " dirs found.\n";
+  std::cerr << NumDirLookups << " dir lookups, "
+            << NumDirCacheMisses << " dir cache misses.\n";
+  std::cerr << NumFileLookups << " file lookups, "
+            << NumFileCacheMisses << " file cache misses.\n";
+  
+  //std::cerr << PagesMapped << BytesOfPagesMapped << FSLookups;
+}