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

via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Thu Jan 16 12:20:42 PST 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-directx

Author: None (joaosaffran)

<details>
<summary>Changes</summary>

Adding support for Root Signature Flags Element extraction and writing to DXContainer.
- Adding an analysis to deal with RootSignature metadata definition
- Adding validation for Flag
- writing RootSignature blob into DXIL

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


7 Files Affected:

- (modified) llvm/lib/Target/DirectX/CMakeLists.txt (+1-1) 
- (modified) llvm/lib/Target/DirectX/DXContainerGlobals.cpp (+22) 
- (added) llvm/lib/Target/DirectX/DXILRootSignature.cpp (+147) 
- (added) llvm/lib/Target/DirectX/DXILRootSignature.h (+74) 
- (modified) llvm/lib/Target/DirectX/DirectX.h (+3) 
- (modified) llvm/lib/Target/DirectX/DirectXTargetMachine.cpp (+1) 
- (added) llvm/test/CodeGen/DirectX/ContainerData/RootSignature-Flags.ll (+38) 


``````````diff
diff --git a/llvm/lib/Target/DirectX/CMakeLists.txt b/llvm/lib/Target/DirectX/CMakeLists.txt
index 26315db891b577..89fe494dea71cc 100644
--- a/llvm/lib/Target/DirectX/CMakeLists.txt
+++ b/llvm/lib/Target/DirectX/CMakeLists.txt
@@ -33,7 +33,7 @@ add_llvm_target(DirectXCodeGen
   DXILResourceAccess.cpp
   DXILShaderFlags.cpp
   DXILTranslateMetadata.cpp
-
+  DXILRootSignature.cpp
   LINK_COMPONENTS
   Analysis
   AsmPrinter
diff --git a/llvm/lib/Target/DirectX/DXContainerGlobals.cpp b/llvm/lib/Target/DirectX/DXContainerGlobals.cpp
index 7a0bd6a7c88692..ac70bd3771dadf 100644
--- a/llvm/lib/Target/DirectX/DXContainerGlobals.cpp
+++ b/llvm/lib/Target/DirectX/DXContainerGlobals.cpp
@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "DXILRootSignature.h"
 #include "DXILShaderFlags.h"
 #include "DirectX.h"
 #include "llvm/ADT/SmallVector.h"
@@ -26,6 +27,7 @@
 #include "llvm/Pass.h"
 #include "llvm/Support/MD5.h"
 #include "llvm/Transforms/Utils/ModuleUtils.h"
+#include <optional>
 
 using namespace llvm;
 using namespace llvm::dxil;
@@ -41,6 +43,7 @@ class DXContainerGlobals : public llvm::ModulePass {
   GlobalVariable *buildSignature(Module &M, Signature &Sig, StringRef Name,
                                  StringRef SectionName);
   void addSignature(Module &M, SmallVector<GlobalValue *> &Globals);
+  void addRootSignature(Module &M, SmallVector<GlobalValue *> &Globals);
   void addResourcesForPSV(Module &M, PSVRuntimeInfo &PSV);
   void addPipelineStateValidationInfo(Module &M,
                                       SmallVector<GlobalValue *> &Globals);
@@ -60,6 +63,7 @@ class DXContainerGlobals : public llvm::ModulePass {
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.setPreservesAll();
     AU.addRequired<ShaderFlagsAnalysisWrapper>();
+    AU.addRequired<RootSignatureAnalysisWrapper>();
     AU.addRequired<DXILMetadataAnalysisWrapperPass>();
     AU.addRequired<DXILResourceTypeWrapperPass>();
     AU.addRequired<DXILResourceBindingWrapperPass>();
@@ -73,6 +77,7 @@ bool DXContainerGlobals::runOnModule(Module &M) {
   Globals.push_back(getFeatureFlags(M));
   Globals.push_back(computeShaderHash(M));
   addSignature(M, Globals);
+  addRootSignature(M, Globals);
   addPipelineStateValidationInfo(M, Globals);
   appendToCompilerUsed(M, Globals);
   return true;
@@ -144,6 +149,23 @@ void DXContainerGlobals::addSignature(Module &M,
   Globals.emplace_back(buildSignature(M, OutputSig, "dx.osg1", "OSG1"));
 }
 
+void DXContainerGlobals::addRootSignature(Module &M,
+                                          SmallVector<GlobalValue *> &Globals) {
+
+  std::optional<ModuleRootSignature> MRS =
+      getAnalysis<RootSignatureAnalysisWrapper>().getRootSignature();
+  if (!MRS.has_value())
+    return;
+
+  SmallString<256> Data;
+  raw_svector_ostream OS(Data);
+  MRS->write(OS);
+
+  Constant *Constant =
+      ConstantDataArray::getString(M.getContext(), Data, /*AddNull*/ false);
+  Globals.emplace_back(buildContainerGlobal(M, Constant, "dx.rts0", "RTS0"));
+}
+
 void DXContainerGlobals::addResourcesForPSV(Module &M, PSVRuntimeInfo &PSV) {
   const DXILBindingMap &DBM =
       getAnalysis<DXILResourceBindingWrapperPass>().getBindingMap();
diff --git a/llvm/lib/Target/DirectX/DXILRootSignature.cpp b/llvm/lib/Target/DirectX/DXILRootSignature.cpp
new file mode 100644
index 00000000000000..cabaec3671078e
--- /dev/null
+++ b/llvm/lib/Target/DirectX/DXILRootSignature.cpp
@@ -0,0 +1,147 @@
+//===- 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/BinaryFormat/DXContainer.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/IR/Module.h"
+#include <cassert>
+
+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) {
+  this->Version = Version;
+  bool HasError = false;
+
+  for (unsigned int Sid = 0; Sid < Root->getNumOperands(); Sid++) {
+    // This should be an if, for error handling
+    MDNode *Node = cast<MDNode>(Root->getOperand(Sid));
+
+    // Not sure what use this for...
+    // Metadata *Func = Node->getOperand(0).get();
+
+    MDNode *Elements = cast<MDNode>(Node->getOperand(1).get());
+    assert(Elements && "Invalid Metadata type on root signature");
+
+    for (unsigned int Eid = 0; Eid < Elements->getNumOperands(); Eid++) {
+      MDNode *Element = cast<MDNode>(Elements->getOperand(Eid));
+      assert(Element && "Invalid Metadata type on root element");
+
+      HasError = HasError || parseRootSignatureElement(this, Element);
+    }
+  }
+  return HasError;
+}
+
+void ModuleRootSignature::write(raw_ostream &OS) {
+  dxbc::RootSignatureDesc Out{this->Version, this->Flags};
+
+  if (sys::IsBigEndianHost) {
+    Out.swapBytes();
+  }
+
+  OS.write(reinterpret_cast<const char *>(&Out),
+           sizeof(dxbc::RootSignatureDesc));
+}
+
+AnalysisKey RootSignatureAnalysis::Key;
+
+ModuleRootSignature RootSignatureAnalysis::run(Module &M,
+                                               ModuleAnalysisManager &AM) {
+  ModuleRootSignature MRSI;
+
+  NamedMDNode *RootSignatureNode = M.getNamedMetadata("dx.rootsignatures");
+  if (RootSignatureNode) {
+    MRSI.parse(1, RootSignatureNode);
+  }
+
+  return MRSI;
+}
+
+//===----------------------------------------------------------------------===//
+bool RootSignatureAnalysisWrapper::runOnModule(Module &M) {
+  ModuleRootSignature MRS;
+
+  NamedMDNode *RootSignatureNode = M.getNamedMetadata("dx.rootsignatures");
+  if (RootSignatureNode) {
+    MRS.parse(1, RootSignatureNode);
+    this->MRS = MRS;
+  }
+
+  return false;
+}
+
+void RootSignatureAnalysisWrapper::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.setPreservesAll();
+}
+
+char RootSignatureAnalysisWrapper::ID = 0;
+
+INITIALIZE_PASS(RootSignatureAnalysisWrapper, "dx-root-signature-analysis",
+                "DXIL Root Signature Analysis", true, true)
diff --git a/llvm/lib/Target/DirectX/DXILRootSignature.h b/llvm/lib/Target/DirectX/DXILRootSignature.h
new file mode 100644
index 00000000000000..de82afcdc8c467
--- /dev/null
+++ b/llvm/lib/Target/DirectX/DXILRootSignature.h
@@ -0,0 +1,74 @@
+//===- DXILRootSignature.h - 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 "llvm/IR/Metadata.h"
+#include "llvm/IR/PassManager.h"
+#include "llvm/Pass.h"
+#include <optional>
+
+namespace llvm {
+namespace dxil {
+
+enum class RootSignatureElementKind {
+  None = 0,
+  RootFlags = 1,
+  RootConstants = 2,
+  RootDescriptor = 3,
+  DescriptorTable = 4,
+  StaticSampler = 5
+};
+
+struct ModuleRootSignature {
+  uint32_t Version;
+  uint32_t Flags;
+
+  ModuleRootSignature() = default;
+
+  bool parse(int32_t Version, NamedMDNode *Root);
+  void write(raw_ostream &OS);
+};
+
+class RootSignatureAnalysis : public AnalysisInfoMixin<RootSignatureAnalysis> {
+  friend AnalysisInfoMixin<RootSignatureAnalysis>;
+  static AnalysisKey Key;
+
+public:
+  RootSignatureAnalysis() = default;
+
+  using Result = ModuleRootSignature;
+
+  ModuleRootSignature run(Module &M, ModuleAnalysisManager &AM);
+};
+
+/// Wrapper pass for the legacy pass manager.
+///
+/// This is required because the passes that will depend on this are codegen
+/// passes which run through the legacy pass manager.
+class RootSignatureAnalysisWrapper : public ModulePass {
+  std::optional<ModuleRootSignature> MRS;
+
+public:
+  static char ID;
+
+  RootSignatureAnalysisWrapper() : ModulePass(ID) {}
+
+  const std::optional<ModuleRootSignature> &getRootSignature() { return MRS; }
+
+  bool runOnModule(Module &M) override;
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
+};
+
+} // namespace dxil
+} // namespace llvm
diff --git a/llvm/lib/Target/DirectX/DirectX.h b/llvm/lib/Target/DirectX/DirectX.h
index add23587de7d58..953ac3eb820987 100644
--- a/llvm/lib/Target/DirectX/DirectX.h
+++ b/llvm/lib/Target/DirectX/DirectX.h
@@ -77,6 +77,9 @@ void initializeDXILPrettyPrinterLegacyPass(PassRegistry &);
 /// Initializer for dxil::ShaderFlagsAnalysisWrapper pass.
 void initializeShaderFlagsAnalysisWrapperPass(PassRegistry &);
 
+/// Initializer for dxil::RootSignatureAnalysisWrapper pass.
+void initializeRootSignatureAnalysisWrapperPass(PassRegistry &);
+
 /// Initializer for DXContainerGlobals pass.
 void initializeDXContainerGlobalsPass(PassRegistry &);
 
diff --git a/llvm/lib/Target/DirectX/DirectXTargetMachine.cpp b/llvm/lib/Target/DirectX/DirectXTargetMachine.cpp
index ecb1bf775f8578..93745d7a5cb0d2 100644
--- a/llvm/lib/Target/DirectX/DirectXTargetMachine.cpp
+++ b/llvm/lib/Target/DirectX/DirectXTargetMachine.cpp
@@ -61,6 +61,7 @@ extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeDirectXTarget() {
   initializeDXILTranslateMetadataLegacyPass(*PR);
   initializeDXILResourceMDWrapperPass(*PR);
   initializeShaderFlagsAnalysisWrapperPass(*PR);
+  initializeRootSignatureAnalysisWrapperPass(*PR);
   initializeDXILFinalizeLinkageLegacyPass(*PR);
 }
 
diff --git a/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-Flags.ll b/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-Flags.ll
new file mode 100644
index 00000000000000..ffbf5e9ffd1d32
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/ContainerData/RootSignature-Flags.ll
@@ -0,0 +1,38 @@
+; RUN: opt %s -dxil-embed -dxil-globals -S -o - | FileCheck %s
+; RUN: llc %s --filetype=obj -o - | obj2yaml | FileCheck %s --check-prefix=DXC
+
+target triple = "dxil-unknown-shadermodel6.0-compute"
+
+; CHECK: @dx.rts0 = private constant [8 x i8]  c"{{.*}}", section "RTS0", align 4
+
+
+define void @main() #0 {
+entry:
+  ret void
+}
+
+attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
+
+
+!dx.rootsignatures = !{!2} ; list of function/root signature pairs
+!2 = !{ ptr @main, !3 } ; function, root signature
+!3 = !{ !4 } ; list of root signature elements
+!4 = !{ !"RootFlags", i32 1 } ; 1 = allow_input_assembler_input_layout
+
+
+; DXC:    - Name: RTS0
+; DXC-NEXT: Size: 8
+; DXC-NEXT: RootSignature:
+; DXC-NEXT:   Version: 1
+; DXC-NEXT:   AllowInputAssemblerInputLayout: true
+; DXC-NEXT:   DenyVertexShaderRootAccess: false
+; DXC-NEXT:   DenyHullShaderRootAccess: false
+; DXC-NEXT:   DenyDomainShaderRootAccess: false
+; DXC-NEXT:   DenyGeometryShaderRootAccess: false
+; DXC-NEXT:   DenyPixelShaderRootAccess: false
+; DXC-NEXT:   AllowStreamOutput: false
+; DXC-NEXT:   LocalRootSignature: false
+; DXC-NEXT:   DenyAmplificationShaderRootAccess: false
+; DXC-NEXT:   DenyMeshShaderRootAccess: false
+; DXC-NEXT:   CBVSRVUAVHeapDirectlyIndexed: false
+; DXC-NEXT:   SamplerHeapDirectlyIndexed: false

``````````

</details>


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


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