Lift VFS from clang to llvm (NFC)

This patch moves the virtual file system form clang to llvm so it can be
used by more projects.

Concretely the patch:
 - Moves VirtualFileSystem.{h|cpp} from clang/Basic to llvm/Support.
 - Moves the corresponding unit test from clang to llvm.
 - Moves the vfs namespace from clang::vfs to llvm::vfs.
 - Formats the lines affected by this change, mostly this is the result of
   the added llvm namespace.

RFC on the mailing list:
http://lists.llvm.org/pipermail/llvm-dev/2018-October/126657.html

Differential revision: https://reviews.llvm.org/D52783

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@344140 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 19 insertions, 15 deletions

diff --git a/lib/Lex/HeaderSearch.cpp b/lib/Lex/HeaderSearch.cpp
index c475336ca5..27eca0a81c 100644
--- a/lib/Lex/HeaderSearch.cpp
+++ b/lib/Lex/HeaderSearch.cpp
@@ -17,7 +17,6 @@
 #include "clang/Basic/IdentifierTable.h"
 #include "clang/Basic/Module.h"
 #include "clang/Basic/SourceManager.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Lex/DirectoryLookup.h"
 #include "clang/Lex/ExternalPreprocessorSource.h"
 #include "clang/Lex/HeaderMap.h"
@@ -35,6 +34,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <algorithm>
 #include <cassert>
 #include <cstddef>
@@ -1571,8 +1571,9 @@ void HeaderSearch::collectAllModules(SmallVectorImpl<Module *> &Modules) {
                                 DirNative);
 
         // Search each of the ".framework" directories to load them as modules.
-        vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
-        for (vfs::directory_iterator Dir = FS.dir_begin(DirNative, EC), DirEnd;
+        llvm::vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
+        for (llvm::vfs::directory_iterator Dir = FS.dir_begin(DirNative, EC),
+                                           DirEnd;
              Dir != DirEnd && !EC; Dir.increment(EC)) {
           if (llvm::sys::path::extension(Dir->path()) != ".framework")
             continue;
@@ -1639,8 +1640,8 @@ void HeaderSearch::loadSubdirectoryModuleMaps(DirectoryLookup &SearchDir) {
   std::error_code EC;
   SmallString<128> DirNative;
   llvm::sys::path::native(SearchDir.getDir()->getName(), DirNative);
-  vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
-  for (vfs::directory_iterator Dir = FS.dir_begin(DirNative, EC), DirEnd;
+  llvm::vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
+  for (llvm::vfs::directory_iterator Dir = FS.dir_begin(DirNative, EC), DirEnd;
        Dir != DirEnd && !EC; Dir.increment(EC)) {
     bool IsFramework = llvm::sys::path::extension(Dir->path()) == ".framework";
     if (IsFramework == SearchDir.isFramework())
diff --git a/lib/Lex/ModuleMap.cpp b/lib/Lex/ModuleMap.cpp
index b6a6e26d6a..d44bf124ff 100644
--- a/lib/Lex/ModuleMap.cpp
+++ b/lib/Lex/ModuleMap.cpp
@@ -22,7 +22,6 @@
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/TargetInfo.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/HeaderSearchOptions.h"
 #include "clang/Lex/LexDiagnostic.h"
@@ -43,6 +42,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cassert>
@@ -1020,9 +1020,10 @@ Module *ModuleMap::inferFrameworkModule(const DirectoryEntry *FrameworkDir,
     = StringRef(FrameworkDir->getName());
   llvm::sys::path::append(SubframeworksDirName, "Frameworks");
   llvm::sys::path::native(SubframeworksDirName);
-  vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
-  for (vfs::directory_iterator Dir = FS.dir_begin(SubframeworksDirName, EC),
-                               DirEnd;
+  llvm::vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
+  for (llvm::vfs::directory_iterator
+           Dir = FS.dir_begin(SubframeworksDirName, EC),
+           DirEnd;
        Dir != DirEnd && !EC; Dir.increment(EC)) {
     if (!StringRef(Dir->path()).endswith(".framework"))
       continue;
@@ -2394,8 +2395,9 @@ void ModuleMapParser::parseUmbrellaDirDecl(SourceLocation UmbrellaLoc) {
     // uncommonly used Tcl module on Darwin platforms.
     std::error_code EC;
     SmallVector<Module::Header, 6> Headers;
-    vfs::FileSystem &FS = *SourceMgr.getFileManager().getVirtualFileSystem();
-    for (vfs::recursive_directory_iterator I(FS, Dir->getName(), EC), E;
+    llvm::vfs::FileSystem &FS =
+        *SourceMgr.getFileManager().getVirtualFileSystem();
+    for (llvm::vfs::recursive_directory_iterator I(FS, Dir->getName(), EC), E;
          I != E && !EC; I.increment(EC)) {
       if (const FileEntry *FE = SourceMgr.getFileManager().getFile(I->path())) {
 
diff --git a/lib/Lex/PPLexerChange.cpp b/lib/Lex/PPLexerChange.cpp
index 2ec075fa34..76ccfb73fd 100644
--- a/lib/Lex/PPLexerChange.cpp
+++ b/lib/Lex/PPLexerChange.cpp
@@ -304,9 +304,10 @@ void Preprocessor::diagnoseMissingHeaderInUmbrellaDir(const Module &Mod) {
 
   ModuleMap &ModMap = getHeaderSearchInfo().getModuleMap();
   const DirectoryEntry *Dir = Mod.getUmbrellaDir().Entry;
-  vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
+  llvm::vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
   std::error_code EC;
-  for (vfs::recursive_directory_iterator Entry(FS, Dir->getName(), EC), End;
+  for (llvm::vfs::recursive_directory_iterator Entry(FS, Dir->getName(), EC),
+       End;
        Entry != End && !EC; Entry.increment(EC)) {
     using llvm::StringSwitch;
 
diff --git a/lib/Lex/PTHLexer.cpp b/lib/Lex/PTHLexer.cpp
index 45cff56dca..74c7c5ea7e 100644
--- a/lib/Lex/PTHLexer.cpp
+++ b/lib/Lex/PTHLexer.cpp
@@ -715,8 +715,8 @@ public:
               FL.getBase()) {}
 
   LookupResult getStat(StringRef Path, FileData &Data, bool isFile,
-                       std::unique_ptr<vfs::File> *F,
-                       vfs::FileSystem &FS) override {
+                       std::unique_ptr<llvm::vfs::File> *F,
+                       llvm::vfs::FileSystem &FS) override {
     // Do the lookup for the file's data in the PTH file.
     CacheTy::iterator I = Cache.find(Path);