Revert "[ClangImporter] Merge Swift & Clang VFS"

include/swift/AST/DiagnosticsClangImporter.def

@@ -91,6 +91,10 @@ WARNING(implicit_bridging_header_imported_from_module,none,
         "is deprecated and will be removed in a later version of Swift",
         (StringRef, Identifier))
 
+WARNING(clang_vfs_overlay_is_ignored,none,
+        "ignoring '-ivfsoverlay' options provided to '-Xcc' in favor of "
+        "'-vfsoverlay'", ())
+
 #ifndef DIAG_NO_UNDEF
 # if defined(DIAG)
 #  undef DIAG

include/swift/Basic/SourceManager.h

@@ -23,16 +23,10 @@
 
 namespace swift {
 
-static inline llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem>
-getRealOverlayFileSystem() {
-  return llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem>(
-      new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem()));
-}
-
 /// This class manages and owns source buffers.
 class SourceManager {
   llvm::SourceMgr LLVMSourceMgr;
-  llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> FileSystem;
+  llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FileSystem;
   unsigned CodeCompletionBufferID = 0U;
   unsigned CodeCompletionOffset;
 
@@ -55,9 +49,9 @@ class SourceManager {
   mutable std::pair<const char *, const VirtualFile*> CachedVFile = {nullptr, nullptr};
 
 public:
-  SourceManager(llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> FS =
+  SourceManager(llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS =
-                    getRealOverlayFileSystem())
+                    llvm::vfs::getRealFileSystem())
-      : FileSystem(FS) {}
+    : FileSystem(FS) {}
 
   llvm::SourceMgr &getLLVMSourceMgr() {
     return LLVMSourceMgr;
@@ -66,12 +60,11 @@ public:
     return LLVMSourceMgr;
   }
 
-  void
+  void setFileSystem(llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS) {
-  setFileSystem(llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> FS) {
     FileSystem = FS;
   }
 
-  llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> getFileSystem() {
+  llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> getFileSystem() {
     return FileSystem;
   }
 
@@ -261,3 +254,4 @@ private:
 } // end namespace swift
 
 #endif // SWIFT_BASIC_SOURCEMANAGER_H
+

lib/ClangImporter/ClangImporter.cpp

@@ -1012,35 +1012,14 @@ ClangImporter::create(ASTContext &ctx,
 
   // Set up the file manager.
   {
-    if (instance.getHeaderSearchOpts().VFSOverlayFiles.empty()) {
+    if (!ctx.SearchPathOpts.VFSOverlayFiles.empty()) {
-      instance.setVirtualFileSystem(ctx.SourceMgr.getFileSystem());
+      // If the clang instance has overlays it means the user has provided
-    } else {
+      // -ivfsoverlay options and swift -vfsoverlay options.  We're going to
-      // Initialize the clang VFS from its compiler invocation.
+      // clobber their file system with our own, so warn about it.
-      instance.createFileManager();
+      if (!instance.getHeaderSearchOpts().VFSOverlayFiles.empty()) {
-
+        ctx.Diags.diagnose(SourceLoc(), diag::clang_vfs_overlay_is_ignored);
-      // Create a new overlay file system for the clang importer with the clang
-      // VFS as its root.
-      auto ClangImporterFS =
-          llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem>(
-              new llvm::vfs::OverlayFileSystem(
-                  &instance.getVirtualFileSystem()));
-
-      auto SwiftFS = ctx.SourceMgr.getFileSystem();
-      auto it = SwiftFS->overlays_rbegin();
-      auto end = SwiftFS->overlays_rend();
-
-      // The Swift file system is an overlay file system with the real file
-      // system as its root. Skip the root so we query the other overlays
-      // before falling back to the real file system.
-      it++;
-
-      // Add all remaining Swift overlay file systems to the new file system.
-      while (it != end) {
-        ClangImporterFS->pushOverlay(*it);
-        it++;
       }
-
+      instance.setVirtualFileSystem(ctx.SourceMgr.getFileSystem());
-      instance.setVirtualFileSystem(ClangImporterFS);
     }
     instance.createFileManager();
   }

lib/Frontend/Frontend.cpp

@@ -235,6 +235,9 @@ static bool loadAndValidateVFSOverlay(
     const llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> &BaseFS,
     const llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> &OverlayFS,
     DiagnosticEngine &Diag) {
+  // FIXME: It should be possible to allow chained lookup of later VFS overlays
+  // through the mapping defined by earlier overlays.
+  // See rdar://problem/39440687
   auto Buffer = BaseFS->getBufferForFile(File);
   if (!Buffer) {
     Diag.diagnose(SourceLoc(), diag::cannot_open_file, File,
@@ -261,7 +264,14 @@ bool CompilerInstance::setUpVirtualFileSystemOverlays() {
     hadAnyFailure |=
         loadAndValidateVFSOverlay(File, BaseFS, OverlayFS, Diagnostics);
   }
-  SourceMgr.setFileSystem(OverlayFS);
+
+  // If we successfully loaded all the overlays, let the source manager and
+  // diagnostic engine take advantage of the overlay file system.
+  if (!hadAnyFailure &&
+      (OverlayFS->overlays_begin() != OverlayFS->overlays_end())) {
+    SourceMgr.setFileSystem(OverlayFS);
+  }
+
   return hadAnyFailure;
 }
 

lib/Frontend/ParseableInterfaceModuleLoader.cpp

@@ -273,7 +273,7 @@ static Optional<StringRef> getRelativeDepPath(StringRef DepPath,
 /// output path.
 /// \note Needs to be in the swift namespace so CompilerInvocation can see it.
 class swift::ParseableInterfaceBuilder {
-  llvm::vfs::OverlayFileSystem &fs;
+  llvm::vfs::FileSystem &fs;
   DiagnosticEngine &diags;
   const StringRef interfacePath;
   const StringRef moduleName;
@@ -765,7 +765,7 @@ class ParseableInterfaceModuleLoaderImpl {
   using AccessPathElem = std::pair<Identifier, SourceLoc>;
   friend class swift::ParseableInterfaceModuleLoader;
   ASTContext &ctx;
-  llvm::vfs::OverlayFileSystem &fs;
+  llvm::vfs::FileSystem &fs;
   DiagnosticEngine &diags;
   ModuleRebuildInfo rebuildInfo;
   const StringRef modulePath;

test/Frontend/Inputs/vfs/a-modulemap

@@ -1,7 +1,3 @@
 module VFSMappedModule {
   header "VFSMappedModule.h"
 }
-
-module YetAnotherVFSMappedModule {
-  header "YetAnotherVFSMappedModule.h"
-}

test/Frontend/Inputs/vfs/b-header

@@ -1 +0,0 @@
-#define MAJOR_SUCCESS 1

test/Frontend/Inputs/vfs/quaternary-vfsoverlay.yaml

@@ -1,17 +0,0 @@
-{
-  'version': 0,
-  'use-external-names': false,
-  'roots': [
-    {
-      'name': 'OUT_DIR', 'type': 'directory',
-      'contents': [
-        { 'name': 'YetAnotherVFSMappedModule.h', 'type': 'file',
-          'external-contents': 'INPUT_DIR/vfs/b-header'
-        },
-        { 'name': 'YetAnotherVFSMappedModule.framework/Headers/VFSMappedModule.h', 'type': 'file',
-          'external-contents': 'INPUT_DIR/vfs/b-header'
-        },
-      ]
-    },
-  ]
-}

test/Frontend/vfs.swift

@@ -2,7 +2,6 @@
 // RUN: sed -e "s|INPUT_DIR|%/S/Inputs|g" -e "s|OUT_DIR|%/t|g" %S/Inputs/vfs/vfsoverlay.yaml > %t/overlay.yaml
 // RUN: sed -e "s|INPUT_DIR|%/S/Inputs|g" -e "s|OUT_DIR|%/t|g" %S/Inputs/vfs/secondary-vfsoverlay.yaml > %t/secondary-overlay.yaml
 // RUN: sed -e "s|INPUT_DIR|%/S/Inputs|g" -e "s|OUT_DIR|%/t|g" %S/Inputs/vfs/tertiary-vfsoverlay.yaml > %t/tertiary-overlay.yaml
-// RUN: sed -e "s|INPUT_DIR|%/S/Inputs|g" -e "s|OUT_DIR|%/t|g" %S/Inputs/vfs/quaternary-vfsoverlay.yaml > %t/quaternary-vfsoverlay.yaml
 
 // RUN: not %target-swift-frontend -vfsoverlay %/t/overlay.yaml -typecheck %s %/t/mapped-file.swift -serialize-diagnostics-path %/t/basic.dia 2>&1 | %FileCheck -check-prefix=BASIC_MAPPING_ERROR %s
 // RUN: c-index-test -read-diagnostics %/t/basic.dia 2>&1 | %FileCheck -check-prefix=BASIC_MAPPING_ERROR %s
@@ -21,11 +20,10 @@
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %/t -DTEST_VFS_CLANG_IMPORTER -Xcc -ivfsoverlay -Xcc %/t/overlay.yaml -typecheck %/s
 
 // If we see -ivfsoverlay and -vfsoverlay, we'll clobber Clang's VFS with our own.
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %/t -DTEST_VFS_CLANG_IMPORTER -DTEST_VFS_CLANG_IMPORTER_MERGE -vfsoverlay %/t/overlay.yaml -Xcc -ivfsoverlay -Xcc %/t/quaternary-vfsoverlay.yaml -typecheck %/s  2>&1
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %/t -DTEST_VFS_CLANG_IMPORTER -vfsoverlay %/t/overlay.yaml -Xcc -ivfsoverlay -Xcc %/t/overlay.yaml -typecheck %/s  2>&1 | %FileCheck -check-prefix=WARN_VFS_CLOBBERED %s
+
+// WARN_VFS_CLOBBERED: warning: ignoring '-ivfsoverlay' options provided to '-Xcc' in favor of '-vfsoverlay'
 
 #if TEST_VFS_CLANG_IMPORTER
 import VFSMappedModule
-#if TEST_VFS_CLANG_IMPORTER_MERGE
-import YetAnotherVFSMappedModule
-#endif
 #endif

unittests/FrontendTool/ModuleLoadingTests.cpp

@@ -87,10 +87,8 @@ protected:
     SourceManager sourceMgr;
 
     // Create a file system that tracks how many times a file has been opened.
-    llvm::IntrusiveRefCntPtr<OpenTrackingFileSystem> baseFS(
+    llvm::IntrusiveRefCntPtr<OpenTrackingFileSystem> fs(
-        new OpenTrackingFileSystem(sourceMgr.getFileSystem()));
+      new OpenTrackingFileSystem(sourceMgr.getFileSystem()));
-    auto fs = llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem>(
-        new llvm::vfs::OverlayFileSystem(baseFS));
 
     sourceMgr.setFileSystem(fs);
     PrintingDiagnosticConsumer printingConsumer;
@@ -128,7 +126,7 @@ protected:
     ASSERT_TRUE(fs->exists(cachedModulePath));
 
     // Assert that we've only opened this file once, to write it.
-    ASSERT_EQ((unsigned)1, baseFS->numberOfOpens(cachedModulePath));
+    ASSERT_EQ((unsigned)1, fs->numberOfOpens(cachedModulePath));
 
     auto bufOrErr = fs->getBufferForFile(cachedModulePath);
     ASSERT_TRUE(bufOrErr);