Fix case-sensitivity of inferred framework modules

Just because we can open a directory named "COcoa.framework" doesn't
mean we should provide a "COcoa" module on a case-insensitive filesystem.

llvm-svn: 212975

clang/lib/Lex/ModuleMap.cpp

@@ -624,6 +624,12 @@ ModuleMap::inferFrameworkModule(StringRef ModuleName,
     StringRef FrameworkDirName
       = SourceMgr.getFileManager().getCanonicalName(FrameworkDir);
 
+    // In case this is a case-insensitive filesystem, make sure the canonical
+    // directory name matches ModuleName exactly. Modules are case-sensitive.
+    // FIXME: we should be able to give a fix-it hint for the correct spelling.
+    if (llvm::sys::path::stem(FrameworkDirName) != ModuleName)
+      return nullptr;
+
     bool canInfer = false;
     if (llvm::sys::path::has_parent_path(FrameworkDirName)) {
       // Figure out the parent path.

clang/test/Modules/inferred-framework-case.m

@@ -0,0 +1,5 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -fmodules-cache-path=%t -fmodules -F %S/Inputs %s -verify -DA
+
+@import MOdule; // expected-error{{module 'MOdule' not found}}
+@import Module;