Add lexing for example keyword and enum

Author: inbelic

clang/include/clang/Parse/HLSLRootSignatureTokenKinds.def

@@ -20,6 +20,17 @@
 #ifndef PUNCTUATOR
 #define PUNCTUATOR(X,Y) TOK(pu_ ## X)
 #endif
+#ifndef KEYWORD
+#define KEYWORD(X) TOK(kw_ ## X)
+#endif
+#ifndef ENUM
+#define ENUM(NAME, LIT) TOK(en_ ## NAME)
+#endif
+
+// Defines the various types of enum
+#ifndef DESCRIPTOR_RANGE_OFFSET_ENUM
+#define DESCRIPTOR_RANGE_OFFSET_ENUM(NAME, LIT) ENUM(NAME, LIT)
+#endif
 
 // General Tokens:
 TOK(invalid)
@@ -38,5 +49,14 @@ PUNCTUATOR(comma,   ',')
 PUNCTUATOR(or,      '|')
 PUNCTUATOR(equal,   '=')
 
+// RootElement Keywords:
+KEYWORD(DescriptorTable)
+
+// Descriptor Range Offset Enum:
+DESCRIPTOR_RANGE_OFFSET_ENUM(DescriptorRangeOffsetAppend, "DESCRIPTOR_RANGE_OFFSET_APPEND")
+
+#undef DESCRIPTOR_RANGE_OFFSET_ENUM
+#undef ENUM
+#undef KEYWORD
 #undef PUNCTUATOR
 #undef TOK

clang/include/clang/Parse/ParseHLSLRootSignature.h

@@ -20,6 +20,7 @@
 
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/StringSwitch.h"
 
 namespace clang {
 namespace hlsl {

clang/lib/Parse/ParseHLSLRootSignature.cpp

@@ -147,9 +147,26 @@ bool RootSignatureLexer::LexToken(RootSignatureToken &Result) {
     return false;
   }
 
-  // Unable to match on any token type
-  PP.getDiagnostics().Report(Result.TokLoc, diag::err_hlsl_invalid_token);
-  return true;
+  // Keywords and Enums:
+  StringRef TokSpelling =
+      Buffer.take_while([](char C) { return isalnum(C) || C == '_'; });
+
+  // Define a large string switch statement for all the keywords and enums
+  auto Switch = llvm::StringSwitch<TokenKind>(TokSpelling);
+#define KEYWORD(NAME) Switch.Case(#NAME, TokenKind::kw_##NAME);
+#define ENUM(NAME, LIT) Switch.CaseLower(LIT, TokenKind::en_##NAME);
+#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;
+  AdvanceBuffer(TokSpelling.size());
+  return false;
 }
 
 } // namespace hlsl

clang/unittests/Parse/ParseHLSLRootSignatureTest.cpp

@@ -147,6 +147,10 @@ TEST_F(ParseHLSLRootSignatureTest, ValidLexAllTokensTest) {
     b0 t43 u987 s234
 
     (),|=
+
+    DescriptorTable
+
+    DESCRIPTOR_RANGE_OFFSET_APPEND
   )cc";
 
   TrivialModuleLoader ModLoader;