================
@@ -0,0 +1,159 @@
+//===- 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/ADT/Twine.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Module.h"
+#include <cstdint>
+
+using namespace llvm;
+using namespace llvm::dxil;
+
+static bool reportError(Twine Message) {
+ report_fatal_error(Message, false);
+ return true;
+}
+
+static bool parseRootFlags(ModuleRootSignature *MRS, MDNode *RootFlagNode) {
+
+ if (RootFlagNode->getNumOperands() != 2)
+ return reportError("Invalid format for RootFlag Element");
+
+ auto *Flag = mdconst::extract<ConstantInt>(RootFlagNode->getOperand(1));
+ uint32_t 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
+ if ((Value & ~0x80000fff) != 0)
+ return reportError("Invalid flag value for RootFlag");
+
+ MRS->Flags = Value;
+ return false;
+}
+
+static bool parseRootSignatureElement(ModuleRootSignature *MRS,
+ MDNode *Element) {
+ MDString *ElementText = cast<MDString>(Element->getOperand(0));
+ if (ElementText == nullptr)
+ return reportError("Invalid format for Root Element");
+
+ 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:
+ return reportError("Invalid Root Element: " + ElementText->getString());
+ break;
+ }
+
+ return true;
+}
+
+bool ModuleRootSignature::parse(int32_t Version, NamedMDNode *Root) {
+ this->Version = Version;
+ bool HasError = false;
+
+ /** Root Signature are specified as following in the metadata:
+
+ !dx.rootsignatures = !{!2} ; list of function/root signature pairs
+ !2 = !{ ptr @main, !3 } ; function, root signature
+ !3 = !{ !4, !5, !6, !7 } ; list of root signature elements
+
+ So for each MDNode inside dx.rootsignatures NamedMDNode
+ (the Root parameter of this function), the parsing process needs
+ to loop through each of it's operand and process the pairs function
+ signature pair.
+ */
+
+ for (unsigned int Sid = 0; Sid < Root->getNumOperands(); Sid++) {
+ MDNode *Node = dyn_cast<MDNode>(Root->getOperand(Sid));
+
+ if (Node == nullptr || Node->getNumOperands() != 2)
----------------
damyanp wrote:
```
if (Node == nullptr || Node->getNumOperands() != 2)
```
Can `Node` really ever be nullptr? I'm not sure it can.
https://github.com/llvm/llvm-project/pull/123147
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