Support relative paths in VFSFromYAML

Use llvm::sys::fs::make_absolute to get an absolute path before
matching. Also, allow "." directories to enable testing.  ".." is still
not supported, and will require crossing file system boundaries to
implement correctly.

llvm-svn: 202903

2 files changed, 21 insertions, 3 deletions

diff --git a/clang/lib/Basic/VirtualFileSystem.cpp b/clang/lib/Basic/VirtualFileSystem.cpp
index 43b203a334e..dc0f52f72b4 100644
--- a/clang/lib/Basic/VirtualFileSystem.cpp
+++ b/clang/lib/Basic/VirtualFileSystem.cpp
@@ -733,8 +733,12 @@ VFSFromYAML *VFSFromYAML::create(MemoryBuffer *Buffer,
 }
 
 ErrorOr<Entry *> VFSFromYAML::lookupPath(const Twine &Path_) {
-  SmallVector<char, 256> Storage;
-  StringRef Path = Path_.toNullTerminatedStringRef(Storage);
+  SmallString<256> Path;
+  Path_.toVector(Path);
+
+  // Handle relative paths
+  if (error_code EC = sys::fs::make_absolute(Path))
+    return EC;
 
   if (Path.empty())
     return error_code(errc::invalid_argument, system_category());
@@ -753,7 +757,10 @@ ErrorOr<Entry *> VFSFromYAML::lookupPath(const Twine &Path_) {
 ErrorOr<Entry *> VFSFromYAML::lookupPath(sys::path::const_iterator Start,
                                          sys::path::const_iterator End,
                                          Entry *From) {
-  // FIXME: handle . and ..
+  if (Start->equals("."))
+    ++Start;
+
+  // FIXME: handle ..
   if (CaseSensitive ? !Start->equals(From->getName())
                     : !Start->equals_lower(From->getName()))
     // failure to match
diff --git a/clang/test/VFS/relative-path.c b/clang/test/VFS/relative-path.c
new file mode 100644
index 00000000000..e7101fb3a82
--- /dev/null
+++ b/clang/test/VFS/relative-path.c
@@ -0,0 +1,11 @@
+// RUN: mkdir -p %t
+// RUN: cd %t
+// RUN: sed -e "s:INPUT_DIR:%S/Inputs:g" -e "s:OUT_DIR:%t:g" %S/Inputs/vfsoverlay.yaml > %t.yaml
+// RUN: %clang_cc1 -Werror -I . -ivfsoverlay %t.yaml -fsyntax-only %s
+// REQUIRES: shell
+
+#include "not_real.h"
+
+void foo() {
+  bar();
+}