Since we're stuck with realpath for the header <-> module mapping,

factor the realpath calls into FileManager::getCanonicalName() so we
can cache the results of this epically slow operation. 5% speedup on
my modules test, and realpath drops out of the profile.

llvm-svn: 173542

1 files changed, 5 insertions, 6 deletions

diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index 14d44cc3da2..64329255184 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -268,6 +268,10 @@ const FileEntry *DirectoryLookup::LookupFile(
   return Result;
 }
 
+/// FIXME: HACK HACK HACK!
+static llvm::DenseMap<const DirectoryEntry *, const DirectoryEntry *>
+  TopFrameworkDirs;
+
 /// \brief Given a framework directory, find the top-most framework directory.
 ///
 /// \param FileMgr The file manager to use for directory lookups.
@@ -280,7 +284,6 @@ getTopFrameworkDir(FileManager &FileMgr, StringRef DirName,
   assert(llvm::sys::path::extension(DirName) == ".framework" &&
          "Not a framework directory");
 
-#ifdef LLVM_ON_UNIX
   // Note: as an egregious but useful hack we use the real path here, because
   // frameworks moving between top-level frameworks to embedded frameworks tend
   // to be symlinked, and we base the logical structure of modules on the
@@ -295,12 +298,8 @@ getTopFrameworkDir(FileManager &FileMgr, StringRef DirName,
   //
   // Similar issues occur when a top-level framework has moved into an
   // embedded framework.
-  char RealDirName[PATH_MAX];
-  if (realpath(DirName.str().c_str(), RealDirName))
-    DirName = RealDirName;
-#endif
-
   const DirectoryEntry *TopFrameworkDir = FileMgr.getDirectory(DirName);
+  DirName = FileMgr.getCanonicalName(TopFrameworkDir);
   do {
     // Get the parent directory name.
     DirName = llvm::sys::path::parent_path(DirName);