[HLSL][RootSignature] Add optional parameter for RootConstants

- extends `parseRootConstantParams` and the struct to include the
optional parameters of a RootConstant

- adds corresponding unit tests

Author: inbelic

clang/include/clang/Parse/ParseHLSLRootSignature.h

@@ -82,6 +82,8 @@ class RootSignatureParser {
   struct ParsedConstantParams {
     std::optional<llvm::hlsl::rootsig::Register> Reg;
     std::optional<uint32_t> Num32BitConstants;
+    std::optional<uint32_t> Space;
+    std::optional<llvm::hlsl::rootsig::ShaderVisibility> Visibility;
   };
   std::optional<ParsedConstantParams> parseRootConstantParams();
 

clang/lib/Parse/ParseHLSLRootSignature.cpp

@@ -78,6 +78,13 @@ std::optional<RootConstants> RootSignatureParser::parseRootConstants() {
 
   Constants.Reg = Params->Reg.value();
 
+  // Fill in optional parameters
+  if (Params->Visibility.has_value())
+    Constants.Visibility = Params->Visibility.value();
+
+  if (Params->Space.has_value())
+    Constants.Space = Params->Space.value();
+
   if (consumeExpectedToken(TokenKind::pu_r_paren,
                            diag::err_hlsl_unexpected_end_of_params,
                            /*param of=*/TokenKind::kw_RootConstants))
@@ -247,6 +254,40 @@ RootSignatureParser::parseRootConstantParams() {
         return std::nullopt;
       Params.Reg = Reg;
     }
+
+    // `space` `=` POS_INT
+    if (tryConsumeExpectedToken(TokenKind::kw_space)) {
+      if (Params.Space.has_value()) {
+        getDiags().Report(CurToken.TokLoc, diag::err_hlsl_rootsig_repeat_param)
+            << CurToken.TokKind;
+        return std::nullopt;
+      }
+
+      if (consumeExpectedToken(TokenKind::pu_equal))
+        return std::nullopt;
+
+      auto Space = parseUIntParam();
+      if (!Space.has_value())
+        return std::nullopt;
+      Params.Space = Space;
+    }
+
+    // `visibility` `=` SHADER_VISIBILITY
+    if (tryConsumeExpectedToken(TokenKind::kw_visibility)) {
+      if (Params.Visibility.has_value()) {
+        getDiags().Report(CurToken.TokLoc, diag::err_hlsl_rootsig_repeat_param)
+            << CurToken.TokKind;
+        return std::nullopt;
+      }
+
+      if (consumeExpectedToken(TokenKind::pu_equal))
+        return std::nullopt;
+
+      auto Visibility = parseShaderVisibility();
+      if (!Visibility.has_value())
+        return std::nullopt;
+      Params.Visibility = Visibility;
+    }
   } while (tryConsumeExpectedToken(TokenKind::pu_comma));
 
   return Params;

clang/unittests/Parse/ParseHLSLRootSignatureTest.cpp

@@ -255,7 +255,9 @@ TEST_F(ParseHLSLRootSignatureTest, ValidSamplerFlagsTest) {
 TEST_F(ParseHLSLRootSignatureTest, ValidParseRootConsantsTest) {
   const llvm::StringLiteral Source = R"cc(
     RootConstants(num32BitConstants = 1, b0),
-    RootConstants(b42, num32BitConstants = 4294967295)
+    RootConstants(b42, space = 3, num32BitConstants = 4294967295,
+      visibility = SHADER_VISIBILITY_HULL
+    )
   )cc";
 
   TrivialModuleLoader ModLoader;
@@ -278,12 +280,16 @@ TEST_F(ParseHLSLRootSignatureTest, ValidParseRootConsantsTest) {
   ASSERT_EQ(std::get<RootConstants>(Elem).Num32BitConstants, 1u);
   ASSERT_EQ(std::get<RootConstants>(Elem).Reg.ViewType, RegisterType::BReg);
   ASSERT_EQ(std::get<RootConstants>(Elem).Reg.Number, 0u);
+  ASSERT_EQ(std::get<RootConstants>(Elem).Space, 0u);
+  ASSERT_EQ(std::get<RootConstants>(Elem).Visibility, ShaderVisibility::All);
 
   Elem = Elements[1];
   ASSERT_TRUE(std::holds_alternative<RootConstants>(Elem));
   ASSERT_EQ(std::get<RootConstants>(Elem).Num32BitConstants, 4294967295u);
   ASSERT_EQ(std::get<RootConstants>(Elem).Reg.ViewType, RegisterType::BReg);
   ASSERT_EQ(std::get<RootConstants>(Elem).Reg.Number, 42u);
+  ASSERT_EQ(std::get<RootConstants>(Elem).Space, 3u);
+  ASSERT_EQ(std::get<RootConstants>(Elem).Visibility, ShaderVisibility::Hull);
 
   ASSERT_TRUE(Consumer->isSatisfied());
 }

llvm/include/llvm/Frontend/HLSL/HLSLRootSignature.h

@@ -58,6 +58,8 @@ struct Register {
 struct RootConstants {
   uint32_t Num32BitConstants;
   Register Reg;
+  uint32_t Space = 0;
+  ShaderVisibility Visibility = ShaderVisibility::All;
 };
 
 // Models the end of a descriptor table and stores its visibility