[SemaCXX] add -Woverride-init alias to -Winitializer-overrides

Summary:
https://bugs.llvm.org/show_bug.cgi?id=40251
https://github.com/ClangBuiltLinux/linux/issues/307

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: cfe-commits, nathanchance, srhines

Differential Revision: https://reviews.llvm.org/D56522

llvm-svn: 350877

clang/docs/DiagnosticsReference.rst

@@ -7885,6 +7885,10 @@ This diagnostic is enabled by default.
 |                                                                                               |+---------------------+|
 +-----------------------------------------------------------------------------------------------+-----------------------+
 
+-Woverride-init
+--------------
+Synonym for `-Winitializer-overrides`_.
+
 
 -Woverride-module
 -----------------

clang/include/clang/Basic/DiagnosticGroups.td

@@ -365,6 +365,8 @@ def NullArithmetic : DiagGroup<"null-arithmetic">;
 def NullCharacter : DiagGroup<"null-character">;
 def NullDereference : DiagGroup<"null-dereference">;
 def InitializerOverrides : DiagGroup<"initializer-overrides">;
+// For compatibility with GCC; -Woverride-init = -Winitializer-overrides
+def : DiagGroup<"override-init", [InitializerOverrides]>;
 def NonNull : DiagGroup<"nonnull">;
 def NonPODVarargs : DiagGroup<"non-pod-varargs">;
 def ClassVarargs : DiagGroup<"class-varargs", [NonPODVarargs]>;

clang/test/SemaCXX/designated-initializers.cpp

@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify -Winitializer-overrides %s
+// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify -Woverride-init %s
 
 template <typename T> struct Foo {
   struct SubFoo {