Add "randomize_layout" attribute

Author: connorkuehl

clang/include/clang/Basic/Attr.td

@@ -3186,3 +3186,10 @@ def ObjCExternallyRetained : InheritableAttr {
   let Subjects = SubjectList<[NonParmVar, Function, Block, ObjCMethod]>;
   let Documentation = [ObjCExternallyRetainedDocs];
 }
+
+def Randomized : InheritableAttr {
+  let Spellings = [GCC<"randomize_layout">, Declspec<"randomize_layout">,
+    Keyword<"randomize_layout">];
+  let Subjects = SubjectList<[Record]>;
+  let Documentation = [Undocumented];
+}

clang/lib/Sema/SemaDeclAttr.cpp

@@ -6788,6 +6788,9 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
     handleSimpleAttributeWithExclusions<NoSpeculativeLoadHardeningAttr,
                                         SpeculativeLoadHardeningAttr>(S, D, AL);
     break;
+  case ParsedAttr::AT_Randomized:
+    handleSimpleAttribute<RandomizedAttr>(S, D, AL);
+    break;
   case ParsedAttr::AT_CodeSeg:
     handleCodeSegAttr(S, D, AL);
     break;