Honour -ivfsoverlay in ASTUnit to match clang

This allows code indexing, etc. to use the VFS in the same way as the
compiler.

llvm-svn: 206309

3 files changed, 62 insertions, 33 deletions

diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index c4f7596e003..5035dac53cf 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -692,7 +692,8 @@ ASTUnit *ASTUnit::LoadFromASTFile(const std::string &Filename,
   AST->OnlyLocalDecls = OnlyLocalDecls;
   AST->CaptureDiagnostics = CaptureDiagnostics;
   AST->Diagnostics = Diags;
-  AST->FileMgr = new FileManager(FileSystemOpts);
+  IntrusiveRefCntPtr<vfs::FileSystem> VFS = vfs::getRealFileSystem();
+  AST->FileMgr = new FileManager(FileSystemOpts, VFS);
   AST->UserFilesAreVolatile = UserFilesAreVolatile;
   AST->SourceMgr = new SourceManager(AST->getDiagnostics(),
                                      AST->getFileManager(),
@@ -1093,10 +1094,9 @@ bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
          "IR inputs not support here!");
 
   // Configure the various subsystems.
-  // FIXME: Should we retain the previous file manager?
   LangOpts = &Clang->getLangOpts();
   FileSystemOpts = Clang->getFileSystemOpts();
-  FileMgr = new FileManager(FileSystemOpts);
+  // Re-use the existing FileManager
   SourceMgr = new SourceManager(getDiagnostics(), *FileMgr,
                                 UserFilesAreVolatile);
   TheSema.reset();
@@ -1598,9 +1598,14 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
   TopLevelDecls.clear();
   TopLevelDeclsInPreamble.clear();
   PreambleDiagnostics.clear();
-  
+
+  IntrusiveRefCntPtr<vfs::FileSystem> VFS =
+      createVFSFromCompilerInvocation(Clang->getInvocation(), getDiagnostics());
+  if (!VFS)
+    return nullptr;
+
   // Create a file manager object to provide access to and cache the filesystem.
-  Clang->setFileManager(new FileManager(Clang->getFileSystemOpts()));
+  Clang->setFileManager(new FileManager(Clang->getFileSystemOpts(), VFS));
   
   // Create the source manager.
   Clang->setSourceManager(new SourceManager(getDiagnostics(),
@@ -1758,7 +1763,11 @@ ASTUnit *ASTUnit::create(CompilerInvocation *CI,
   AST->Diagnostics = Diags;
   AST->Invocation = CI;
   AST->FileSystemOpts = CI->getFileSystemOpts();
-  AST->FileMgr = new FileManager(AST->FileSystemOpts);
+  IntrusiveRefCntPtr<vfs::FileSystem> VFS =
+      createVFSFromCompilerInvocation(*CI, *Diags);
+  if (!VFS)
+    return nullptr;
+  AST->FileMgr = new FileManager(AST->FileSystemOpts, VFS);
   AST->UserFilesAreVolatile = UserFilesAreVolatile;
   AST->SourceMgr = new SourceManager(AST->getDiagnostics(), *AST->FileMgr,
                                      UserFilesAreVolatile);
@@ -1781,6 +1790,8 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocationAction(
     // Create the AST unit.
     OwnAST.reset(create(CI, Diags, CaptureDiagnostics, UserFilesAreVolatile));
     AST = OwnAST.get();
+    if (!AST)
+      return nullptr;
   }
   
   if (!ResourceFilesPath.empty()) {
@@ -1950,7 +1961,11 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocation(CompilerInvocation *CI,
     = IncludeBriefCommentsInCodeCompletion;
   AST->Invocation = CI;
   AST->FileSystemOpts = CI->getFileSystemOpts();
-  AST->FileMgr = new FileManager(AST->FileSystemOpts);
+  IntrusiveRefCntPtr<vfs::FileSystem> VFS =
+      createVFSFromCompilerInvocation(*CI, *Diags);
+  if (!VFS)
+    return nullptr;
+  AST->FileMgr = new FileManager(AST->FileSystemOpts, VFS);
   AST->UserFilesAreVolatile = UserFilesAreVolatile;
   
   // Recover resources if we crash before exiting this method.
@@ -2017,7 +2032,11 @@ ASTUnit *ASTUnit::LoadFromCommandLine(
   AST->Diagnostics = Diags;
   Diags = 0; // Zero out now to ease cleanup during crash recovery.
   AST->FileSystemOpts = CI->getFileSystemOpts();
-  AST->FileMgr = new FileManager(AST->FileSystemOpts);
+  IntrusiveRefCntPtr<vfs::FileSystem> VFS =
+      createVFSFromCompilerInvocation(*CI, *Diags);
+  if (!VFS)
+    return nullptr;
+  AST->FileMgr = new FileManager(AST->FileSystemOpts, VFS);
   AST->OnlyLocalDecls = OnlyLocalDecls;
   AST->CaptureDiagnostics = CaptureDiagnostics;
   AST->TUKind = TUKind;
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index b22ea9a07f6..6177a96fa7b 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -8,12 +8,12 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Frontend/CompilerInvocation.h"
-#include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/Version.h"
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/Options.h"
 #include "clang/Driver/Util.h"
+#include "clang/Frontend/FrontendDiagnostic.h"
 #include "clang/Frontend/LangStandard.h"
 #include "clang/Frontend/Utils.h"
 #include "clang/Lex/HeaderSearchOptions.h"
@@ -1907,4 +1907,31 @@ void BuryPointer(const void *Ptr) {
     return;
   GraveYard[Idx] = Ptr;
 }
+
+IntrusiveRefCntPtr<vfs::FileSystem>
+createVFSFromCompilerInvocation(const CompilerInvocation &CI,
+                                DiagnosticsEngine &Diags) {
+  if (CI.getHeaderSearchOpts().VFSOverlayFiles.empty())
+    return vfs::getRealFileSystem();
+
+  IntrusiveRefCntPtr<vfs::OverlayFileSystem>
+    Overlay(new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
+  // earlier vfs files are on the bottom
+  for (const std::string &File : CI.getHeaderSearchOpts().VFSOverlayFiles) {
+    std::unique_ptr<llvm::MemoryBuffer> Buffer;
+    if (llvm::errc::success != llvm::MemoryBuffer::getFile(File, Buffer)) {
+      Diags.Report(diag::err_missing_vfs_overlay_file) << File;
+      return IntrusiveRefCntPtr<vfs::FileSystem>();
+    }
+
+    IntrusiveRefCntPtr<vfs::FileSystem> FS =
+        vfs::getVFSFromYAML(Buffer.release(), /*DiagHandler*/0);
+    if (!FS.getPtr()) {
+      Diags.Report(diag::err_invalid_vfs_overlay) << File;
+      return IntrusiveRefCntPtr<vfs::FileSystem>();
+    }
+    Overlay->pushOverlay(FS);
+  }
+  return Overlay;
 }
+} // end namespace clang
diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index dc4dd89371a..dfe3d85ba73 100644
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -211,30 +211,13 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
     return true;
   }
 
-  if (!CI.getHeaderSearchOpts().VFSOverlayFiles.empty()) {
-    IntrusiveRefCntPtr<vfs::OverlayFileSystem>
-        Overlay(new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
-    // earlier vfs files are on the bottom
-    const std::vector<std::string> &Files =
-        CI.getHeaderSearchOpts().VFSOverlayFiles;
-    for (std::vector<std::string>::const_iterator I = Files.begin(),
-                                                  E = Files.end();
-         I != E; ++I) {
-      std::unique_ptr<llvm::MemoryBuffer> Buffer;
-      if (llvm::errc::success != llvm::MemoryBuffer::getFile(*I, Buffer)) {
-        CI.getDiagnostics().Report(diag::err_missing_vfs_overlay_file) << *I;
-        goto failure;
-      }
-
-      IntrusiveRefCntPtr<vfs::FileSystem> FS =
-          vfs::getVFSFromYAML(Buffer.release(), /*DiagHandler*/ 0);
-      if (!FS.getPtr()) {
-        CI.getDiagnostics().Report(diag::err_invalid_vfs_overlay) << *I;
-        goto failure;
-      }
-      Overlay->pushOverlay(FS);
-    }
-    CI.setVirtualFileSystem(Overlay);
+  if (!CI.hasVirtualFileSystem()) {
+    if (IntrusiveRefCntPtr<vfs::FileSystem> VFS =
+          createVFSFromCompilerInvocation(CI.getInvocation(),
+                                          CI.getDiagnostics()))
+      CI.setVirtualFileSystem(VFS);
+    else
+      goto failure;
   }
 
   // Set up the file and source managers, if needed.