review: remove unique invalid_token lexing error

- similarily, we can let the unexpected_token diagnostics reporting
handle this error by passing up an invalid token and provide more
context

Author: inbelic

clang/include/clang/Basic/DiagnosticLexKinds.td

@@ -1023,7 +1023,6 @@ let CategoryName = "Root Signature Lexical Issue" in {
   def err_hlsl_expected_number_literal: Error<"expected numberic literal">;
   def err_hlsl_number_literal_overflow :
     Error<"integer literal '%0' is too large to be represented in a 32-bit integer type">;
-  def err_hlsl_invalid_token: Error<"unable to lex a valid Root Signature token">;
   def err_hlsl_invalid_register_literal: Error<"expected unsigned integer literal as part of register">;
 }
 

clang/lib/Parse/ParseHLSLRootSignature.cpp

@@ -88,8 +88,8 @@ bool RootSignatureLexer::LexToken(RootSignatureToken &Result) {
 
   // All following tokens require at least one additional character
   if (Buffer.size() <= 1) {
-    PP.getDiagnostics().Report(Result.TokLoc, diag::err_hlsl_invalid_token);
-    return true;
+    Result = RootSignatureToken(SourceLoc);
+    return false;
   }
 
   // Peek at the next character to deteremine token type
@@ -143,13 +143,7 @@ bool RootSignatureLexer::LexToken(RootSignatureToken &Result) {
 #include "clang/Parse/HLSLRootSignatureTokenKinds.def"
 
   // Then attempt to retreive a string from it
-  auto Kind = Switch.Default(TokenKind::invalid);
-  if (Kind == TokenKind::invalid) {
-    PP.getDiagnostics().Report(Result.TokLoc, diag::err_hlsl_invalid_token);
-    return true;
-  }
-
-  Result.Kind = Kind;
+  Result.Kind = Switch.Default(TokenKind::invalid);
   AdvanceBuffer(TokSpelling.size());
   return false;
 }

clang/unittests/Parse/ParseHLSLRootSignatureTest.cpp

@@ -325,23 +325,4 @@ TEST_F(ParseHLSLRootSignatureTest, InvalidLexRegNumberTest) {
   ASSERT_FALSE(Consumer->IsSatisfied());
 }
 
-TEST_F(ParseHLSLRootSignatureTest, InvalidLexIdentifierTest) {
-  // This test will check that the lexing fails due to no valid token
-  const llvm::StringLiteral Source = R"cc(
-    notAToken
-  )cc";
-
-  TrivialModuleLoader ModLoader;
-  auto PP = CreatePP(Source, ModLoader);
-  auto TokLoc = SourceLocation();
-
-  // Test correct diagnostic produced
-  Consumer->SetExpected(diag::err_hlsl_invalid_token);
-
-  hlsl::RootSignatureLexer Lexer(Source, TokLoc, *PP);
-
-  ASSERT_TRUE(Lexer.ConsumeToken());
-  ASSERT_TRUE(Consumer->IsSatisfied());
-}
-
 } // anonymous namespace