Fix PR 30440

[arphaman]

Summary

This patch fixes PR 30440 by initializing CXXNameMangler's FunctionTypeDepth in the two constructors added in r274222 (The commit that caused this regression).

[DmitryPolukhin]

LGTM, added Richard in case he has something to add.

[DmitryPolukhin]

I think we need to fix this regression.

lib/AST/ItaniumMangle.cpp

public:
   CXXNameMangler(ItaniumMangleContextImpl &C, raw_ostream &Out_,
                  const CXXDestructorDecl *D, CXXDtorType Type)
     : Context(C), Out(Out_), Structor(getStructor(D)), StructorType(Type),
       SeqID(0), AbiTagsRoot(AbiTags) { }
 
   CXXNameMangler(CXXNameMangler &Outer, raw_ostream &Out_)
       : Context(Outer.Context), Out(Out_), NullOut(false),
         Structor(Outer.Structor), StructorType(Outer.StructorType),
-        SeqID(Outer.SeqID), AbiTagsRoot(AbiTags),
-        Substitutions(Outer.Substitutions) {}
+        SeqID(Outer.SeqID), FunctionTypeDepth(Outer.FunctionTypeDepth),
+        AbiTagsRoot(AbiTags), Substitutions(Outer.Substitutions) {}
 
   CXXNameMangler(CXXNameMangler &Outer, llvm::raw_null_ostream &Out_)
       : Context(Outer.Context), Out(Out_), NullOut(true),
         Structor(Outer.Structor), StructorType(Outer.StructorType),
-        SeqID(Outer.SeqID), AbiTagsRoot(AbiTags),
-        Substitutions(Outer.Substitutions) {}
+        SeqID(Outer.SeqID), FunctionTypeDepth(Outer.FunctionTypeDepth),
+        AbiTagsRoot(AbiTags), Substitutions(Outer.Substitutions) {}
 
 #if MANGLE_CHECKER
   ~CXXNameMangler() {
     if (Out.str()[0] == '\01')
       return;
 
     int status = 0;
     char *result = abi::__cxa_demangle(Out.str().str().c_str(), 0, 0, &status);

test/CodeGenCXX/mangle-abi-tag.cpp

namespace N19 {
   class C {};
 
   B foo(A, D);
 }
 void f19_test(N19::C<N19::A,  &N19::foo>, N19::F, N19::D) {
 }
 // f19_test(N19::C<N19::A, &N19::foo[abi:B]>, N19::F, N19::D)
 // CHECK-DAG: define void @_Z8f19_testN3N191CINS_1AEXadL_ZNS_3fooB1BES1_NS_1DEEEEENS_1FES2_(
+
+namespace pr30440 {
+
+template<class F> void g(F);
+template<class ...A> auto h(A ...a)->decltype (g (0, g < a > (a) ...)) {
+}
+// CHECK-DAG: define {{.*}} @_ZN7pr304401hIJEEEDTcl1gLi0Espcl1gIL_ZZNS_1hEDpT_E1aEEfp_EEES2_(
+
+void pr30440_test () {
+  h();
+}
+
+}