Use -fms-compatibility to trigger lookup into dep. bases

Update the docs for -fms-extensions and -fms-compatibility to try to
clarify the difference between the two.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@191095 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/UsersManual.rst b/docs/UsersManual.rst
index 05d8f27..15bac1e 100644
--- a/docs/UsersManual.rst
+++ b/docs/UsersManual.rst
@@ -1216,12 +1216,15 @@
 clang has some experimental support for extensions from Microsoft Visual
 C++; to enable it, use the -fms-extensions command-line option. This is
 the default for Windows targets. Note that the support is incomplete;
-enabling Microsoft extensions will silently drop certain constructs
-(including ``__declspec`` and Microsoft-style asm statements).
+some constructs like dllexport on classes with inline methods will be
+ignored with a warning.
 
 clang has a -fms-compatibility flag that makes clang accept enough
-invalid C++ to be able to parse most Microsoft headers. This flag is
-enabled by default for Windows targets.
+invalid C++ to be able to parse most Microsoft headers. For example, it
+allows `unqualified lookup of dependent base class members
+<http://clang.llvm.org/compatibility.html#dep_lookup_bases>`, which is a
+common compatibility issue with clang. This flag is enabled by default
+for Windows targets.
 
 -fdelayed-template-parsing lets clang delay all template instantiation
 until the end of a translation unit. This flag is enabled by default for
diff --git a/lib/Sema/SemaCXXScopeSpec.cpp b/lib/Sema/SemaCXXScopeSpec.cpp
index f79ad2c..674411e 100644
--- a/lib/Sema/SemaCXXScopeSpec.cpp
+++ b/lib/Sema/SemaCXXScopeSpec.cpp
@@ -484,7 +484,7 @@
   
   // FIXME: Deal with ambiguities cleanly.
 
-  if (Found.empty() && !ErrorRecoveryLookup && !getLangOpts().MicrosoftExt) {
+  if (Found.empty() && !ErrorRecoveryLookup && !getLangOpts().MicrosoftMode) {
     // We haven't found anything, and we're not recovering from a
     // different kind of error, so look for typos.
     DeclarationName Name = Found.getLookupName();
@@ -644,7 +644,7 @@
   // public:
   //   void foo() { D::foo2(); }
   // };
-  if (getLangOpts().MicrosoftExt) {
+  if (getLangOpts().MicrosoftMode) {
     DeclContext *DC = LookupCtx ? LookupCtx : CurContext;
     if (DC->isDependentContext() && DC->isFunctionOrMethod()) {
       SS.Extend(Context, &Identifier, IdentifierLoc, CCLoc);
diff --git a/test/SemaTemplate/lookup-dependent-bases.cpp b/test/SemaTemplate/lookup-dependent-bases.cpp
index 4fcfbd1..61fca4a 100644
--- a/test/SemaTemplate/lookup-dependent-bases.cpp
+++ b/test/SemaTemplate/lookup-dependent-bases.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fms-extensions -fsyntax-only -verify %s
+// RUN: %clang_cc1 -fms-compatibility -fsyntax-only -verify %s
 // expected-no-diagnostics
 
 class C {