add support for DescriptorTableClauses

Author: inbelic

clang/test/CodeGenHLSL/RootSignature.hlsl

@@ -5,11 +5,13 @@
 [numthreads(1,1,1)]
 void FirstEntry() {}
 
+// CHECK-DAG: ![[#CBV:]] = !{!"CBV", i32 1, i32 0, i32 0, i32 -1, i32 4}
 // CHECK-DAG: ![[#TABLE:]] = !{!"DescriptorTable"}
 // CHECK-DAG: ![[#SECOND_RS:]] = !{![[#TABLE]]}
 
 #define SampleDescriptorTable \
   "DescriptorTable( " \
+  "  CBV(b0) " \
   ")"
 [shader("compute"), RootSignature(SampleDescriptorTable)]
 [numthreads(1,1,1)]

llvm/lib/Frontend/HLSL/HLSLRootSignature.cpp

@@ -200,7 +200,16 @@ MDNode *MetadataBuilder::BuildDescriptorTable(const DescriptorTable &Table) {
 }
 
 MDNode *MetadataBuilder::BuildDescriptorTableClause(const DescriptorTableClause &Clause) {
-  return MDNode::get(Ctx, {ClauseTypeToName(Ctx, Clause.Type)});
+  IRBuilder<> B(Ctx);
+  return MDNode::get(Ctx, {
+    ClauseTypeToName(Ctx, Clause.Type),
+    ConstantAsMetadata::get(B.getInt32(Clause.NumDescriptors)),
+    ConstantAsMetadata::get(B.getInt32(Clause.Reg.Number)),
+    ConstantAsMetadata::get(B.getInt32(Clause.Space)),
+    ConstantAsMetadata::get(B.getInt32(Clause.Offset)),
+    ConstantAsMetadata::get(
+      B.getInt32(llvm::to_underlying(Clause.Flags))),
+  });
 }
 
 } // namespace rootsig