Index: include/clang/AST/ASTContext.h
===================================================================
--- include/clang/AST/ASTContext.h
+++ include/clang/AST/ASTContext.h
@@ -791,6 +791,11 @@
     Comments.addComment(RC, LangOpts.CommentOpts, BumpAlloc);
   }
 
+  /// \brief Return the RawComment attached to a given declaration, if present.
+  /// Does not check redeclarations or bases.
+  /// Returns nullptr if no comment is attached.
+  const RawComment *getRawCommentForDecl(const Decl *D) const;
+
   /// \brief Return the documentation comment attached to a given declaration.
   /// Returns nullptr if no comment is attached.
   ///
@@ -806,13 +811,13 @@
   ///
   /// \param PP the Preprocessor used with this TU.  Could be nullptr if
   /// preprocessor is not available.
-  comments::FullComment *getCommentForDecl(const Decl *D,
-                                           const Preprocessor *PP) const;
+  comments::FullComment *
+  getParsedCommentForAnyRedecl(const Decl *D, const Preprocessor *PP) const;
 
-  /// Return parsed documentation comment attached to a given declaration.
-  /// Returns nullptr if no comment is attached. Does not look at any
-  /// redeclarations of the declaration.
-  comments::FullComment *getLocalCommentForDeclUncached(const Decl *D) const;
+  /// \brief Return parsed documentation comment attached to a given
+  /// declaration, and not update the cache. Returns nullptr if no comment
+  /// is attached. Does not look at any redeclarations of the declaration.
+  comments::FullComment *getParsedCommentForDeclUncached(const Decl *D) const;
 
   comments::FullComment *cloneFullComment(comments::FullComment *FC,
                                          const Decl *D) const;
Index: lib/AST/ASTContext.cpp
===================================================================
--- lib/AST/ASTContext.cpp
+++ lib/AST/ASTContext.cpp
@@ -407,6 +407,20 @@
   return Raw;
 }
 
+const RawComment *
+ASTContext::getRawCommentForDecl(const Decl *D) const {
+  const RawCommentAndCacheFlags &Raw = getRawCommentForDeclCached(D);
+  const RawComment *RC = Raw.getRaw();
+  if (RC) {
+    // Make sure this cache entry wasn't updated by getRawCommentForAnyRedecl.
+    if (Raw.getOriginalDecl() != D)
+      return nullptr;
+    return RC;
+  }
+  assert(Raw.getKind() == RawCommentAndCacheFlags::NoCommentInDecl);
+  return nullptr;
+}
+
 const RawComment *
 ASTContext::getRawCommentForAnyRedecl(const Decl *D,
                                       const Decl **OriginalDecl) const {
@@ -483,14 +497,15 @@
   return CFC;
 }
 
-comments::FullComment *ASTContext::getLocalCommentForDeclUncached(const Decl *D) const {
+comments::FullComment *
+ASTContext::getParsedCommentForDeclUncached(const Decl *D) const {
   const RawComment *RC = getRawCommentForDeclNoCache(D);
   return RC ? RC->parse(*this, nullptr, D) : nullptr;
 }
 
 comments::FullComment *
-ASTContext::getCommentForDecl(const Decl *D,
-                                    const Preprocessor *PP) const {
+ASTContext::getParsedCommentForAnyRedecl(const Decl *D,
+                                         const Preprocessor *PP) const {
   if (D->isInvalidDecl())
     return nullptr;
   D = adjustDeclToTemplate(D);
@@ -517,13 +532,15 @@
       const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D);
       if (OMD && OMD->isPropertyAccessor())
         if (const ObjCPropertyDecl *PDecl = OMD->findPropertyDecl())
-          if (comments::FullComment *FC = getCommentForDecl(PDecl, PP))
+          if (comments::FullComment *FC =
+                  getParsedCommentForAnyRedecl(PDecl, PP))
             return cloneFullComment(FC, D);
       if (OMD)
         addRedeclaredMethods(OMD, Overridden);
       getOverriddenMethods(dyn_cast<NamedDecl>(D), Overridden);
       for (unsigned i = 0, e = Overridden.size(); i < e; i++)
-        if (comments::FullComment *FC = getCommentForDecl(Overridden[i], PP))
+        if (comments::FullComment *FC =
+                getParsedCommentForAnyRedecl(Overridden[i], PP))
           return cloneFullComment(FC, D);
     }
     else if (const TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(D)) {
@@ -532,19 +549,19 @@
       QualType QT = TD->getUnderlyingType();
       if (const TagType *TT = QT->getAs<TagType>())
         if (const Decl *TD = TT->getDecl())
-          if (comments::FullComment *FC = getCommentForDecl(TD, PP))
+          if (comments::FullComment *FC = getParsedCommentForAnyRedecl(TD, PP))
             return cloneFullComment(FC, D);
     }
     else if (const ObjCInterfaceDecl *IC = dyn_cast<ObjCInterfaceDecl>(D)) {
       while (IC->getSuperClass()) {
         IC = IC->getSuperClass();
-        if (comments::FullComment *FC = getCommentForDecl(IC, PP))
+        if (comments::FullComment *FC = getParsedCommentForAnyRedecl(IC, PP))
           return cloneFullComment(FC, D);
       }
     }
     else if (const ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(D)) {
       if (const ObjCInterfaceDecl *IC = CD->getClassInterface())
-        if (comments::FullComment *FC = getCommentForDecl(IC, PP))
+        if (comments::FullComment *FC = getParsedCommentForAnyRedecl(IC, PP))
           return cloneFullComment(FC, D);
     }
     else if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) {
@@ -560,8 +577,9 @@
         if (const CXXRecordDecl *NonVirtualBase = Ty->getAsCXXRecordDecl()) {
           if (!(NonVirtualBase= NonVirtualBase->getDefinition()))
             continue;
-        
-          if (comments::FullComment *FC = getCommentForDecl((NonVirtualBase), PP))
+
+          if (comments::FullComment *FC =
+                  getParsedCommentForAnyRedecl((NonVirtualBase), PP))
             return cloneFullComment(FC, D);
         }
       }
@@ -575,7 +593,8 @@
         if (const CXXRecordDecl *VirtualBase = Ty->getAsCXXRecordDecl()) {
           if (!(VirtualBase= VirtualBase->getDefinition()))
             continue;
-          if (comments::FullComment *FC = getCommentForDecl((VirtualBase), PP))
+          if (comments::FullComment *FC =
+                  getParsedCommentForAnyRedecl((VirtualBase), PP))
             return cloneFullComment(FC, D);
         }
       }
@@ -588,7 +607,7 @@
   // because comments can contain references to parameter names which can be
   // different across redeclarations.
   if (D != OriginalDecl)
-    return getCommentForDecl(OriginalDecl, PP);
+    return getParsedCommentForAnyRedecl(OriginalDecl, PP);
 
   comments::FullComment *FC = RC->parse(*this, PP, D);
   ParsedComments[Canonical] = FC;
Index: lib/AST/ASTDumper.cpp
===================================================================
--- lib/AST/ASTDumper.cpp
+++ lib/AST/ASTDumper.cpp
@@ -1078,7 +1078,7 @@
       dumpAttr(*I);
 
     if (const FullComment *Comment =
-            D->getASTContext().getLocalCommentForDeclUncached(D))
+            D->getASTContext().getParsedCommentForDeclUncached(D))
       dumpFullComment(Comment);
 
     // Decls within functions are visited by the body.
Index: lib/Sema/SemaDecl.cpp
===================================================================
--- lib/Sema/SemaDecl.cpp
+++ lib/Sema/SemaDecl.cpp
@@ -11915,7 +11915,7 @@
     // the lookahead in the lexer: we've consumed the semicolon and looked
     // ahead through comments.
     for (unsigned i = 0, e = Group.size(); i != e; ++i)
-      Context.getCommentForDecl(Group[i], &PP);
+      Context.getParsedCommentForAnyRedecl(Group[i], &PP);
   }
 }
 
Index: tools/libclang/CXComment.cpp
===================================================================
--- tools/libclang/CXComment.cpp
+++ tools/libclang/CXComment.cpp
@@ -34,7 +34,8 @@
 
   const Decl *D = getCursorDecl(C);
   const ASTContext &Context = getCursorContext(C);
-  const FullComment *FC = Context.getCommentForDecl(D, /*PP=*/nullptr);
+  const FullComment *FC =
+      Context.getParsedCommentForAnyRedecl(D, /*PP=*/nullptr);
 
   return createCXComment(FC, getCursorTU(C));
 }
@@ -403,4 +404,3 @@
       ->convertCommentToXML(FC, XML, cxtu::getASTUnit(TU)->getASTContext());
   return cxstring::createDup(XML.str());
 }
-