[llvm-branch-commits] [llvm] [DXIL] Add support for root signature flag element in DXContainer (PR #123147)

[via llvm-branch-commits]

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@@ -0,0 +1,134 @@
+//===- DXILRootSignature.cpp - DXIL Root Signature helper objects
+//---------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file This file contains helper objects and APIs for working with DXIL
+///       Root Signatures.
+///
+//===----------------------------------------------------------------------===//
+#include "DXILRootSignature.h"
+#include "DirectX.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/IR/Module.h"
+
+using namespace llvm;
+using namespace llvm::dxil;
+
+static bool parseRootFlags(ModuleRootSignature *MRS, MDNode *RootFlagNode) {
+
+  assert(RootFlagNode->getNumOperands() == 2 &&
+         "Invalid format for RootFlag Element");
+  auto *Flag = mdconst::extract<ConstantInt>(RootFlagNode->getOperand(1));
+  auto Value = Flag->getZExtValue();
+
+  // Root Element validation, as specified:
+  // https://github.com/llvm/wg-hlsl/blob/main/proposals/0002-root-signature-in-clang.md#validations-during-dxil-generation
+  assert((Value & ~0x80000fff) == 0 && "Invalid flag for RootFlag Element");
+
+  MRS->Flags = Value;
+  return false;
+}
+
+static bool parseRootSignatureElement(ModuleRootSignature *MRS,
+                                      MDNode *Element) {
+  MDString *ElementText = cast<MDString>(Element->getOperand(0));
+  assert(ElementText != nullptr &&
+         "First preoperty of element is not a string");
+
+  RootSignatureElementKind ElementKind =
+      StringSwitch<RootSignatureElementKind>(ElementText->getString())
+          .Case("RootFlags", RootSignatureElementKind::RootFlags)
+          .Case("RootConstants", RootSignatureElementKind::RootConstants)
+          .Case("RootCBV", RootSignatureElementKind::RootDescriptor)
+          .Case("RootSRV", RootSignatureElementKind::RootDescriptor)
+          .Case("RootUAV", RootSignatureElementKind::RootDescriptor)
+          .Case("Sampler", RootSignatureElementKind::RootDescriptor)
+          .Case("DescriptorTable", RootSignatureElementKind::DescriptorTable)
+          .Case("StaticSampler", RootSignatureElementKind::StaticSampler)
+          .Default(RootSignatureElementKind::None);
+
+  switch (ElementKind) {
+
+  case RootSignatureElementKind::RootFlags: {
+    return parseRootFlags(MRS, Element);
+    break;
+  }
+
+  case RootSignatureElementKind::RootConstants:
+  case RootSignatureElementKind::RootDescriptor:
+  case RootSignatureElementKind::DescriptorTable:
+  case RootSignatureElementKind::StaticSampler:
+  case RootSignatureElementKind::None:
+    llvm_unreachable("Not Implemented yet");
+    break;
+  }
+
+  return true;
+}
+
+bool ModuleRootSignature::parse(int32_t Version, NamedMDNode *Root) {
----------------
joaosaffran wrote:

Root flags are the same regardless of root signature version. The version is required, but currently there is no specified way to change it in the metadata. This will be needed to be address in the future, but I am planing ahead to make it easier in the future. 

https://github.com/llvm/llvm-project/pull/123147