[CrashReproducer] Add support for merging -ivfsoverlay

Merge all VFS mapped files inside -ivfsoverlay inputs into the vfs
overlay provided by the crash reproducer. This is the last missing piece
to allow crash reproducers to fully work with user frameworks; when
combined with headermaps, it allows clang to find additional frameworks.

rdar://problem/27913709

llvm-svn: 290326

1 files changed, 44 insertions, 3 deletions

diff --git a/clang/lib/Basic/VirtualFileSystem.cpp b/clang/lib/Basic/VirtualFileSystem.cpp
index 88d08b4b669..50fcb22faf5 100644
--- a/clang/lib/Basic/VirtualFileSystem.cpp
+++ b/clang/lib/Basic/VirtualFileSystem.cpp
@@ -887,9 +887,6 @@ private:
   RedirectingFileSystem(IntrusiveRefCntPtr<FileSystem> ExternalFS)
       : ExternalFS(std::move(ExternalFS)) {}
 
-  /// \brief Looks up \p Path in \c Roots.
-  ErrorOr<Entry *> lookupPath(const Twine &Path);
-
   /// \brief Looks up the path <tt>[Start, End)</tt> in \p From, possibly
   /// recursing into the contents of \p From if it is a directory.
   ErrorOr<Entry *> lookupPath(sys::path::const_iterator Start,
@@ -899,6 +896,9 @@ private:
   ErrorOr<Status> status(const Twine &Path, Entry *E);
 
 public:
+  /// \brief Looks up \p Path in \c Roots.
+  ErrorOr<Entry *> lookupPath(const Twine &Path);
+
   /// \brief Parses \p Buffer, which is expected to be in YAML format and
   /// returns a virtual file system representing its contents.
   static RedirectingFileSystem *
@@ -1606,6 +1606,47 @@ vfs::getVFSFromYAML(std::unique_ptr<MemoryBuffer> Buffer,
                                        std::move(ExternalFS));
 }
 
+static void getVFSEntries(Entry *SrcE, SmallVectorImpl<StringRef> &Path,
+                          SmallVectorImpl<YAMLVFSEntry> &Entries) {
+  auto Kind = SrcE->getKind();
+  if (Kind == EK_Directory) {
+    auto *DE = dyn_cast<RedirectingDirectoryEntry>(SrcE);
+    assert(DE && "Must be a directory");
+    for (std::unique_ptr<Entry> &SubEntry :
+         llvm::make_range(DE->contents_begin(), DE->contents_end())) {
+      Path.push_back(SubEntry->getName());
+      getVFSEntries(SubEntry.get(), Path, Entries);
+      Path.pop_back();
+    }
+    return;
+  }
+
+  assert(Kind == EK_File && "Must be a EK_File");
+  auto *FE = dyn_cast<RedirectingFileEntry>(SrcE);
+  assert(FE && "Must be a file");
+  SmallString<128> VPath;
+  for (auto &Comp : Path)
+    llvm::sys::path::append(VPath, Comp);
+  Entries.push_back(YAMLVFSEntry(VPath.c_str(), FE->getExternalContentsPath()));
+}
+
+void vfs::collectVFSFromYAML(std::unique_ptr<MemoryBuffer> Buffer,
+                             SourceMgr::DiagHandlerTy DiagHandler,
+                             StringRef YAMLFilePath,
+                             SmallVectorImpl<YAMLVFSEntry> &CollectedEntries,
+                             void *DiagContext,
+                             IntrusiveRefCntPtr<FileSystem> ExternalFS) {
+  RedirectingFileSystem *VFS = RedirectingFileSystem::create(
+      std::move(Buffer), DiagHandler, YAMLFilePath, DiagContext,
+      std::move(ExternalFS));
+  ErrorOr<Entry *> RootE = VFS->lookupPath("/");
+  if (!RootE)
+    return;
+  SmallVector<StringRef, 8> Components;
+  Components.push_back("/");
+  getVFSEntries(*RootE, Components, CollectedEntries);
+}
+
 UniqueID vfs::getNextVirtualUniqueID() {
   static std::atomic<unsigned> UID;
   unsigned ID = ++UID;