[MSVC Compat] Fix typo correction for inclusion directives.

In MSVC compatibility mode we were checking not the typo corrected
filename but the original filename.

Reviewers: christylee, compnerd

Reviewed By: christylee

Subscribers: jkorous, dexonsmith, sammccall, hokein, cfe-commits

Differential Revision: https://reviews.llvm.org/D56631

llvm-svn: 351232

clang/lib/Lex/PPDirectives.cpp

@@ -1813,9 +1813,17 @@ void Preprocessor::HandleIncludeDirective(SourceLocation HashLoc,
           return Filename;
         };
         StringRef TypoCorrectionName = CorrectTypoFilename(Filename);
+        SmallString<128> NormalizedTypoCorrectionPath;
+        if (LangOpts.MSVCCompat) {
+          NormalizedTypoCorrectionPath = TypoCorrectionName.str();
+#ifndef _WIN32
+          llvm::sys::path::native(NormalizedTypoCorrectionPath);
+#endif
+        }
         File = LookupFile(
             FilenameLoc,
-            LangOpts.MSVCCompat ? NormalizedPath.c_str() : TypoCorrectionName,
+            LangOpts.MSVCCompat ? NormalizedTypoCorrectionPath.c_str()
+                                : TypoCorrectionName,
             isAngled, LookupFrom, LookupFromFile, CurDir,
             Callbacks ? &SearchPath : nullptr,
             Callbacks ? &RelativePath : nullptr, &SuggestedModule, &IsMapped);

clang/test/Preprocessor/include-likely-typo.c

@@ -1,3 +1,4 @@
 // RUN: %clang_cc1 %s -verify
+// RUN: %clang_cc1 -fms-compatibility %s -verify
 
 #include "<empty_file_to_include.h>" // expected-error {{'<empty_file_to_include.h>' file not found, did you mean 'empty_file_to_include.h'?}}