Avoid failure to canonicalize '..'.

Also fix completely broken and untested code which was hiding the
primary bug. The !LLVM_ON_UNIX branch of the ifdef was actually a no-op.

I ran into this in the wild. It was causing failures in our SDK build.

Ideally we'd have a perfect llvm::sys::fs::canonical, but at least this
is a step in the right direction, and fixes an obviously broken case.
In some sense the test case I've added here is an integration test. We
should have these routines thoroughly unit tested in llvm::sys::fs.

llvm-svn: 243597

1 files changed, 11 insertions, 8 deletions

diff --git a/clang/lib/Basic/FileManager.cpp b/clang/lib/Basic/FileManager.cpp
index d4927443aa9..3d160569bc8 100644
--- a/clang/lib/Basic/FileManager.cpp
+++ b/clang/lib/Basic/FileManager.cpp
@@ -514,7 +514,7 @@ void FileManager::modifyFileEntry(FileEntry *File,
   File->ModTime = ModificationTime;
 }
 
-/// Remove '.' path components from the given absolute path.
+/// Remove '.' and '..' path components from the given absolute path.
 /// \return \c true if any changes were made.
 // FIXME: Move this to llvm::sys::path.
 bool FileManager::removeDotPaths(SmallVectorImpl<char> &Path) {
@@ -525,24 +525,24 @@ bool FileManager::removeDotPaths(SmallVectorImpl<char> &Path) {
 
   // Skip the root path, then look for traversal in the components.
   StringRef Rel = path::relative_path(P);
-  bool AnyDots = false;
   for (StringRef C : llvm::make_range(path::begin(Rel), path::end(Rel))) {
-    if (C == ".") {
-      AnyDots = true;
+    if (C == ".")
+      continue;
+    if (C == "..") {
+      if (!ComponentStack.empty())
+        ComponentStack.pop_back();
       continue;
     }
     ComponentStack.push_back(C);
   }
 
-  if (!AnyDots)
-    return false;
-
   SmallString<256> Buffer = path::root_path(P);
   for (StringRef C : ComponentStack)
     path::append(Buffer, C);
 
+  bool Changed = (Path != Buffer);
   Path.swap(Buffer);
-  return true;
+  return Changed;
 }
 
 StringRef FileManager::getCanonicalName(const DirectoryEntry *Dir) {
@@ -567,6 +567,9 @@ StringRef FileManager::getCanonicalName(const DirectoryEntry *Dir) {
   llvm::sys::fs::make_absolute(CanonicalNameBuf);
   llvm::sys::path::native(CanonicalNameBuf);
   removeDotPaths(CanonicalNameBuf);
+  char *Mem = CanonicalNameStorage.Allocate<char>(CanonicalNameBuf.size());
+  memcpy(Mem, CanonicalNameBuf.data(), CanonicalNameBuf.size());
+  CanonicalName = StringRef(Mem, CanonicalNameBuf.size());
 #endif
 
   CanonicalDirNames.insert(std::make_pair(Dir, CanonicalName));