[DirectX] Add DXIL metadata `dx.shaderModel`

[beanz]

Summary

This captures the target shader model and pipeline stage into the DXIL
metadata for consumption by the DirectX runtime.

[python3kgae]

llvm/test/CodeGen/DirectX/Metadata/shaderModel-vs.ll

6

Should we report an error for vs_0_0?

[beanz]

llvm/test/CodeGen/DirectX/Metadata/shaderModel-vs.ll

6

Not in the backend. I think we should catch this error in the driver before we start compilation, and in the validator later. The test cases here cover some odd edge cases to ensure the compiler doesn’t crash, but we shouldn’t rely on the backend for producing errors to users unless there are no other alternatives.

[python3kgae]

llvm/lib/Target/DirectX/DXILMetadata.cpp

68

Shall we add "dx.version" in the function too since it is just shader model with offset on major.

[beanz]

llvm/lib/Target/DirectX/DXILMetadata.cpp

68

Yea, that’s probably fair. There is a possibility the two versions may not always be in sync, but we can cross that when we get there.

[beanz]

llvm/lib/Target/DirectX/DXILMetadata.cpp

68

I'd like to have that come in through a separate metadata utility function just for code organization.

[python3kgae]

llvm/lib/Target/DirectX/DXILMetadata.cpp

64

assert for invalid shader profile?

[beanz]

Making unset environment unreachable, and removing cooresponding test case.

llvm/lib/Target/DirectX/DXILMetadata.h

 public:
   ValidatorVersionMD(Module &M);
 
   void update(VersionTuple ValidatorVer);
 
   bool isEmpty();
 };
 
+void createShaderModelMD(Module &M);
+
 } // namespace dxil
 } // namespace llvm
 
 #endif // LLVM_TARGET_DIRECTX_DXILMETADATA_H

llvm/lib/Target/DirectX/DXILMetadata.cpp

 //===- DXILMetadata.cpp - DXIL Metadata 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 for working with DXIL metadata.
 ///
 //===----------------------------------------------------------------------===//
 
 #include "DXILMetadata.h"
+#include "llvm/ADT/Triple.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Support/VersionTuple.h"
 
 using namespace llvm;
 using namespace llvm::dxil;
 
void ValidatorVersionMD::update(VersionTuple ValidatorVer) {
 
   if (isEmpty())
     Entry->addOperand(MDNode::get(Ctx, MDVals));
   else
     Entry->setOperand(0, MDNode::get(Ctx, MDVals));
 }
 
 bool ValidatorVersionMD::isEmpty() { return Entry->getNumOperands() == 0; }
+
+static StringRef getShortShaderStage(Triple::EnvironmentType Env) {
+  switch (Env) {
+  case Triple::Pixel:
+    return "ps";
+  case Triple::Vertex:
+    return "vs";
+  case Triple::Geometry:
+    return "gs";
+  case Triple::Hull:
+    return "hs";
+  case Triple::Domain:
+    return "ds";
+  case Triple::Compute:
+    return "cs";
+  case Triple::Library:
+    return "lib";
+  case Triple::Mesh:
+    return "ms";
+  case Triple::Amplification:
+    return "as";
+  default:
+    break;
+  }
+  llvm_unreachable("Unsupported environment for DXIL generation.");
+  return "";
+}
+
+void dxil::createShaderModelMD(Module &M) {
+  NamedMDNode *Entry = M.getOrInsertNamedMetadata("dx.shaderModel");
+  Triple TT(M.getTargetTriple());
+  VersionTuple Ver = TT.getOSVersion();
+  LLVMContext &Ctx = M.getContext();
+  IRBuilder<> B(Ctx);
+
+  Metadata *Vals[3];
+  Vals[0] = MDString::get(Ctx, getShortShaderStage(TT.getEnvironment()));
+  Vals[1] = ConstantAsMetadata::get(B.getInt32(Ver.getMajor()));
+  Vals[2] = ConstantAsMetadata::get(B.getInt32(Ver.getMinor().value_or(0)));
+  Entry->addOperand(MDNode::get(Ctx, Vals));
+}

llvm/lib/Target/DirectX/DXILTranslateMetadata.cpp

 
 } // namespace
 
 bool DXILTranslateMetadata::runOnModule(Module &M) {
 
   dxil::ValidatorVersionMD ValVerMD(M);
   if (ValVerMD.isEmpty())
     ValVerMD.update(VersionTuple(1, 0));
+  dxil::createShaderModelMD(M);
   return false;
 }
 
 char DXILTranslateMetadata::ID = 0;
 
 ModulePass *llvm::createDXILTranslateMetadataPass() {
   return new DXILTranslateMetadata();
 }
 
 INITIALIZE_PASS(DXILTranslateMetadata, "dxil-metadata-emit",
                 "DXIL Metadata Emit", false, false)

llvm/test/CodeGen/DirectX/Metadata/shaderModel-as.ll

+; RUN: opt -S -dxil-metadata-emit %s | FileCheck %s
+target triple = "dxil-pc-shadermodel6-amplification"
+
+; CHECK: !dx.shaderModel = !{![[SM:[0-9]+]]}
+; CHECK: ![[SM]] = !{!"as", i32 6, i32 0}

llvm/test/CodeGen/DirectX/Metadata/shaderModel-cs.ll

+; RUN: opt -S -dxil-metadata-emit %s | FileCheck %s
+target triple = "dxil-pc-shadermodel6.6-compute"
+
+; CHECK: !dx.shaderModel = !{![[SM:[0-9]+]]}
+; CHECK: ![[SM]] = !{!"cs", i32 6, i32 6}

llvm/test/CodeGen/DirectX/Metadata/shaderModel-gs.ll

+; RUN: opt -S -dxil-metadata-emit %s | FileCheck %s
+target triple = "dxil-pc-shadermodel6.6-geometry"
+
+; CHECK: !dx.shaderModel = !{![[SM:[0-9]+]]}
+; CHECK: ![[SM]] = !{!"gs", i32 6, i32 6}

llvm/test/CodeGen/DirectX/Metadata/shaderModel-hs.ll

+; RUN: opt -S -dxil-metadata-emit %s | FileCheck %s
+target triple = "dxil-pc-shadermodel6.6-hull"
+
+; CHECK: !dx.shaderModel = !{![[SM:[0-9]+]]}
+; CHECK: ![[SM]] = !{!"hs", i32 6, i32 6}

llvm/test/CodeGen/DirectX/Metadata/shaderModel-lib.ll

+; RUN: opt -S -dxil-metadata-emit %s | FileCheck %s
+target triple = "dxil-pc-shadermodel6.3-library"
+
+; CHECK: !dx.shaderModel = !{![[SM:[0-9]+]]}
+; CHECK: ![[SM]] = !{!"lib", i32 6, i32 3}

llvm/test/CodeGen/DirectX/Metadata/shaderModel-ms.ll

+; RUN: opt -S -dxil-metadata-emit %s | FileCheck %s
+target triple = "dxil-pc-shadermodel6.6-mesh"
+
+; CHECK: !dx.shaderModel = !{![[SM:[0-9]+]]}
+; CHECK: ![[SM]] = !{!"ms", i32 6, i32 6}

llvm/test/CodeGen/DirectX/Metadata/shaderModel-ps.ll

+; RUN: opt -S -dxil-metadata-emit %s | FileCheck %s
+target triple = "dxil-pc-shadermodel5.0-pixel"
+
+; CHECK: !dx.shaderModel = !{![[SM:[0-9]+]]}
+; CHECK: ![[SM]] = !{!"ps", i32 5, i32 0}

llvm/test/CodeGen/DirectX/Metadata/shaderModel-vs.ll

+; RUN: opt -S -dxil-metadata-emit %s | FileCheck %s
+target triple = "dxil-pc-shadermodel-vertex"
+
+; CHECK: !dx.shaderModel = !{![[SM:[0-9]+]]}
+; CHECK: ![[SM]] = !{!"vs", i32 0, i32 0}