Frontend: Remove CompilerInstance::VirtualFileSystem, NFC

Remove CompilerInstance::VirtualFileSystem and
CompilerInstance::setVirtualFileSystem, instead relying on the VFS in
the FileManager.  CompilerInstance and its clients already went to some
trouble to make these match.  Now they are guaranteed to match.

As part of this, I added a VFS parameter (defaults to nullptr) to
CompilerInstance::createFileManager, to avoid repeating construction
logic in clients that just wanted to customize the VFS.

https://reviews.llvm.org/D59377

llvm-svn: 357037

1 files changed, 8 insertions, 13 deletions

diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index e7385962994..6c82a6e9532 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -89,10 +89,6 @@ void CompilerInstance::setAuxTarget(TargetInfo *Value) { AuxTarget = Value; }
 
 void CompilerInstance::setFileManager(FileManager *Value) {
   FileMgr = Value;
-  if (Value)
-    VirtualFileSystem = Value->getVirtualFileSystem();
-  else
-    VirtualFileSystem.reset();
 }
 
 void CompilerInstance::setSourceManager(SourceManager *Value) {
@@ -297,13 +293,14 @@ CompilerInstance::createDiagnostics(DiagnosticOptions *Opts,
 
 // File Manager
 
-FileManager *CompilerInstance::createFileManager() {
-  if (!hasVirtualFileSystem()) {
-    IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS =
-        createVFSFromCompilerInvocation(getInvocation(), getDiagnostics());
-    setVirtualFileSystem(VFS);
-  }
-  FileMgr = new FileManager(getFileSystemOpts(), VirtualFileSystem);
+FileManager *CompilerInstance::createFileManager(
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
+  if (!VFS)
+    VFS = FileMgr ? FileMgr->getVirtualFileSystem()
+                  : createVFSFromCompilerInvocation(getInvocation(),
+                                                    getDiagnostics());
+  assert(VFS && "FileManager has no VFS?");
+  FileMgr = new FileManager(getFileSystemOpts(), std::move(VFS));
   return FileMgr.get();
 }
 
@@ -1101,8 +1098,6 @@ compileModuleImpl(CompilerInstance &ImportingInstance, SourceLocation ImportLoc,
                                    ImportingInstance.getDiagnosticClient()),
                              /*ShouldOwnClient=*/true);
 
-  Instance.setVirtualFileSystem(&ImportingInstance.getVirtualFileSystem());
-
   // Note that this module is part of the module build stack, so that we
   // can detect cycles in the module graph.
   Instance.setFileManager(&ImportingInstance.getFileManager());