Downgrade err_mismatched_exception_spec to a ExtWarning in Microsoft mode. MSVC doesn't do any validation on exception specifications.

This remove 1 error when parsing MSVC stl lib with clang.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@127961 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaExceptionSpec.cpp b/lib/Sema/SemaExceptionSpec.cpp
index 490934c..1512a25 100644
--- a/lib/Sema/SemaExceptionSpec.cpp
+++ b/lib/Sema/SemaExceptionSpec.cpp
@@ -100,7 +100,11 @@
   bool IsOperatorNew = OO == OO_New || OO == OO_Array_New;
   bool MissingExceptionSpecification = false;
   bool MissingEmptyExceptionSpecification = false;
-  if (!CheckEquivalentExceptionSpec(PDiag(diag::err_mismatched_exception_spec),
+  unsigned DiagID = diag::err_mismatched_exception_spec;
+  if (getLangOptions().Microsoft)
+    DiagID = diag::war_mismatched_exception_spec; 
+  
+  if (!CheckEquivalentExceptionSpec(PDiag(DiagID),
                                     PDiag(diag::note_previous_declaration),
                                     Old->getType()->getAs<FunctionProtoType>(),
                                     Old->getLocation(),
@@ -247,7 +251,7 @@
     return false;    
   }
 
-  Diag(New->getLocation(), diag::err_mismatched_exception_spec);
+  Diag(New->getLocation(), DiagID);
   Diag(Old->getLocation(), diag::note_previous_declaration);
   return true;
 }
@@ -259,8 +263,11 @@
 bool Sema::CheckEquivalentExceptionSpec(
     const FunctionProtoType *Old, SourceLocation OldLoc,
     const FunctionProtoType *New, SourceLocation NewLoc) {
+  unsigned DiagID = diag::err_mismatched_exception_spec;
+  if (getLangOptions().Microsoft)
+    DiagID = diag::war_mismatched_exception_spec; 
   return CheckEquivalentExceptionSpec(
-                                    PDiag(diag::err_mismatched_exception_spec),
+                                      PDiag(DiagID),
                                       PDiag(diag::note_previous_declaration),
                                       Old, OldLoc, New, NewLoc);
 }
@@ -339,14 +346,6 @@
     return true;
   }
 
-  if (getLangOptions().Microsoft) {
-    // Treat throw(whatever) as throw(...) to be compatible with MS headers.
-    if (OldEST == EST_Dynamic)
-      OldEST = EST_MSAny;
-    if (NewEST == EST_Dynamic)
-      NewEST = EST_MSAny;
-  }
-
   // The MS extension throw(...) is compatible with itself.
   if (OldEST == EST_MSAny && NewEST == EST_MSAny)
     return false;