MS ABI: Don't be so hasty to judge an inheritance model

If we are in the middle of defining the class, don't attempt to
validate previously annotated declarations.  We may not have seen base
specifiers or virtual method declarations yet.

llvm-svn: 200959

clang/lib/Sema/SemaDecl.cpp

@@ -12150,7 +12150,7 @@ void Sema::ActOnFields(Scope *S, SourceLocation RecLoc, Decl *EnclosingDecl,
     if (Record->hasAttrs()) {
       CheckAlignasUnderalignment(Record);
 
-      if (MSInheritanceAttr *IA = Record->getAttr<MSInheritanceAttr>())
+      if (const MSInheritanceAttr *IA = Record->getAttr<MSInheritanceAttr>())
         checkMSInheritanceAttrOnDefinition(cast<CXXRecordDecl>(Record),
                                            IA->getRange(),
                                            IA->getSemanticSpelling());

clang/lib/Sema/SemaDeclAttr.cpp

@@ -2877,16 +2877,23 @@ bool Sema::checkMSInheritanceAttrOnDefinition(
     MSInheritanceAttr::Spelling SemanticSpelling) {
   assert(RD->hasDefinition() && "RD has no definition!");
 
-  if (SemanticSpelling != MSInheritanceAttr::Keyword_unspecified_inheritance &&
-      RD->calculateInheritanceModel() != SemanticSpelling) {
-    Diag(Range.getBegin(), diag::err_mismatched_ms_inheritance)
-        << 0 /*definition*/;
-    Diag(RD->getDefinition()->getLocation(), diag::note_defined_here)
-        << RD->getNameAsString();
-    return true;
-  }
+  // We may not have seen base specifiers or any virtual methods yet.  We will
+  // have to wait until the record is defined to catch any mismatches.
+  if (!RD->getDefinition()->isCompleteDefinition())
+    return false;
 
-  return false;
+  // The unspecified model never matches what a definition could need.
+  if (SemanticSpelling == MSInheritanceAttr::Keyword_unspecified_inheritance)
+    return false;
+
+  if (RD->calculateInheritanceModel() == SemanticSpelling)
+    return false;
+
+  Diag(Range.getBegin(), diag::err_mismatched_ms_inheritance)
+      << 0 /*definition*/;
+  Diag(RD->getDefinition()->getLocation(), diag::note_defined_here)
+      << RD->getNameAsString();
+  return true;
 }
 
 /// handleModeAttr - This attribute modifies the width of a decl with primitive

clang/test/SemaCXX/member-pointer-ms.cpp

@@ -198,4 +198,7 @@ struct __multiple_inheritance B; // expected-error{{inheritance model does not m
 
 struct __multiple_inheritance C {}; // expected-error{{inheritance model does not match definition}}
  // expected-note@-1 {{C defined here}}
+
+struct __virtual_inheritance D;
+struct D : virtual B {};
 }