llvm-undname: Yet more coverage for error paths

- For error returns in demangleSpecialTableNode(),
  demangleLocalStaticGuard(), RTTITypeDescriptor,
  demangleRttiBaseClassDescriptorNode(), demangleUnsigned(),
  demangleUntypedVariable() (via RttiBaseClassArray)

- For ?_A and ?_P which are handled at early levels of the
  demangler but are not implemented in a later stage; this
  is now more obvious

- Replace a "default:" with an explicit list of cases, to
  get -Wswitch check we list all cases

llvm-svn: 362520

llvm/lib/Demangle/MicrosoftDemangle.cpp

@@ -429,10 +429,10 @@ FunctionSymbolNode *Demangler::demangleInitFiniStub(StringView &MangledName,
 
 SymbolNode *Demangler::demangleSpecialIntrinsic(StringView &MangledName) {
   SpecialIntrinsicKind SIK = consumeSpecialIntrinsicKind(MangledName);
-  if (SIK == SpecialIntrinsicKind::None)
-    return nullptr;
 
   switch (SIK) {
+  case SpecialIntrinsicKind::None:
+    return nullptr;
   case SpecialIntrinsicKind::StringLiteralSymbol:
     return demangleStringLiteral(MangledName);
   case SpecialIntrinsicKind::Vftable:
@@ -468,8 +468,13 @@ SymbolNode *Demangler::demangleSpecialIntrinsic(StringView &MangledName) {
     return demangleInitFiniStub(MangledName, false);
   case SpecialIntrinsicKind::DynamicAtexitDestructor:
     return demangleInitFiniStub(MangledName, true);
-  default:
+  case SpecialIntrinsicKind::Typeof:
+  case SpecialIntrinsicKind::UdtReturning:
+    // It's unclear which tools produces these manglings, so demangling
+    // support is not (yet?) implemented.
     break;
+  case SpecialIntrinsicKind::Unknown:
+    DEMANGLE_UNREACHABLE; // Never returned by consumeSpecialIntrinsicKind.
   }
   Error = true;
   return nullptr;

llvm/test/Demangle/invalid-manglings.test

@@ -309,3 +309,48 @@
 ; CHECK-EMPTY:
 ; CHECK-NEXT: ?foo@?0?
 ; CHECK-NEXT: error: Invalid mangled name
+
+??_Sfoo@@1Abar@@
+; CHECK-EMPTY:
+; CHECK-NEXT: ??_Sfoo@@1Abar@@
+; CHECK-NEXT: error: Invalid mangled name
+
+??_Bfoo@@1
+; CHECK-EMPTY:
+; CHECK-NEXT: ??_Bfoo@@1
+; CHECK-NEXT: error: Invalid mangled name
+
+??_R0
+; CHECK-EMPTY:
+; CHECK-NEXT: ??_R0
+; CHECK-NEXT: error: Invalid mangled name
+
+??_R0H
+; CHECK-EMPTY:
+; CHECK-NEXT: ??_R0H
+; CHECK-NEXT: error: Invalid mangled name
+
+??_R0H@8foo
+; CHECK-EMPTY:
+; CHECK-NEXT: ??_R0H@8foo
+; CHECK-NEXT: error: Invalid mangled name
+
+??_R1012?3foo@@
+; CHECK-EMPTY:
+; CHECK-NEXT: ??_R1012?3foo@@
+; CHECK-NEXT: error: Invalid mangled name
+
+??_R2foo@@1
+; CHECK-EMPTY:
+; CHECK-NEXT: ??_R2foo@@1
+; CHECK-NEXT: error: Invalid mangled name
+
+??_A
+; CHECK-EMPTY:
+; CHECK-NEXT: ??_A
+; CHECK-NEXT: error: Invalid mangled name
+
+??_P
+; CHECK-EMPTY:
+; CHECK-NEXT: ??_P
+; CHECK-NEXT: error: Invalid mangled name