[HLSL] Move DXIL validation version out of ModuleFlags

[python3kgae]

Summary

Put DXIL validation version into separate NamedMetadata to avoid update ModuleFlags.

Currently DXIL validation version is saved in ModuleFlags in clang codeGen.
Then in DirectX backend, the data will be extracted from ModuleFlags and cause rebuild of ModuleFlags.
This patch will build NamedMetadata for DXIL validation version and remove the code to rebuild ModuleFlags.

[beanz]

A few nitpicks, otherwise this looks good.

llvm/lib/Target/DirectX/DXILTranslateMetadata.cpp

60–61

Better to remove this function if it is empty. If we need it in the future we can re-introduce it.

78–79

nit: LLVM's coding conventions discourage blanket use of auto. This one is a bit on the edge of the convention. My preference would be for this to have the type because I think that is more clear.

see: https://llvm.org/docs/CodingStandards.html#use-auto-type-deduction-to-make-code-more-readable

79

This should definitely have the type, not auto.

[python3kgae]

Remove empty function and replace auto with correct type.

clang/lib/CodeGen/CGHLSLRuntime.cpp

void addDxilValVersion(StringRef ValVersionStr, llvm::Module &M) {
 
   uint64_t Major = Version.getMajor();
   uint64_t Minor = *Version.getMinor();
 
   auto &Ctx = M.getContext();
   IRBuilder<> B(M.getContext());
   MDNode *Val = MDNode::get(Ctx, {ConstantAsMetadata::get(B.getInt32(Major)),
                                   ConstantAsMetadata::get(B.getInt32(Minor))});
-  StringRef DxilValKey = "dx.valver";
-  M.addModuleFlag(llvm::Module::ModFlagBehavior::AppendUnique, DxilValKey, Val);
+  StringRef DXILValKey = "dx.valver";
+  auto *DXILValMD = M.getOrInsertNamedMetadata(DXILValKey);
+  DXILValMD->addOperand(Val);
 }
 } // namespace
 
 void CGHLSLRuntime::finishCodeGen() {
   auto &TargetOpts = CGM.getTarget().getTargetOpts();
-
   llvm::Module &M = CGM.getModule();
+  Triple T(M.getTargetTriple());
+  if (T.getArch() == Triple::ArchType::dxil)
     addDxilValVersion(TargetOpts.DxilValidatorVersion, M);
 }
 
 void CGHLSLRuntime::annotateHLSLResource(const VarDecl *D, GlobalVariable *GV) {
   const Type *Ty = D->getType()->getPointeeOrArrayElementType();
   if (!Ty)
     return;
   const auto *RD = Ty->getAsCXXRecordDecl();
   if (!RD)

clang/test/CodeGenHLSL/validator_version.hlsl

 // RUN: %clang -cc1 -S -triple dxil-pc-shadermodel6.3-library -S -emit-llvm -xhlsl -validator-version 1.1 -o - %s | FileCheck %s
+// RUN: %clang -cc1 -S -triple spirv32 -S -emit-llvm -xhlsl -validator-version 1.1 -o - %s | FileCheck %s --check-prefix=NOT_DXIL
 
-// CHECK:!"dx.valver", ![[valver:[0-9]+]]}
+// CHECK:!dx.valver = !{![[valver:[0-9]+]]}
 // CHECK:![[valver]] = !{i32 1, i32 1}
 
+// NOT_DXIL-NOT:!dx.valver
+
 float bar(float a, float b);
 
 float foo(float a, float b) {
   return bar(a, b);
 }

llvm/lib/Target/DirectX/DXILTranslateMetadata.cpp

 static VersionTuple loadDXILValidatorVersion(MDNode *ValVerMD) {
   if (ValVerMD->getNumOperands() != DXILVersionNumFields)
     return VersionTuple();
 
   unsigned Major = ConstMDToUint32(ValVerMD->getOperand(0));
   unsigned Minor = ConstMDToUint32(ValVerMD->getOperand(1));
   return VersionTuple(Major, Minor);
 }
 
-static void cleanModuleFlags(Module &M) {
-  constexpr StringLiteral DeadKeys[] = {ValVerKey};
-  // Collect DeadKeys in ModuleFlags.
-  StringSet<> DeadKeySet;
-  for (auto &Key : DeadKeys) {
-    if (M.getModuleFlag(Key))
-      DeadKeySet.insert(Key);
-  }
-  if (DeadKeySet.empty())
-    return;
-
-  SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags;
-  M.getModuleFlagsMetadata(ModuleFlags);
-  NamedMDNode *MDFlags = M.getModuleFlagsMetadata();
-  MDFlags->eraseFromParent();
-  // Add ModuleFlag which not dead.
-  for (auto &Flag : ModuleFlags) {
-    StringRef Key = Flag.Key->getString();
-    if (DeadKeySet.contains(Key))
-      continue;
-    M.addModuleFlag(Flag.Behavior, Key, Flag.Val);
-  }
-}
-
-static void cleanModule(Module &M) { cleanModuleFlags(M); }
-
 namespace {
 class DXILTranslateMetadata : public ModulePass {
 public:
   static char ID; // Pass identification, replacement for typeid
   explicit DXILTranslateMetadata() : ModulePass(ID), ValidatorVer(1, 0) {}
 
   StringRef getPassName() const override { return "DXIL Metadata Emit"; }
 
   bool runOnModule(Module &M) override;
 
 private:
   VersionTuple ValidatorVer;
 };
 
 } // namespace
 
 bool DXILTranslateMetadata::runOnModule(Module &M) {
-  if (MDNode *ValVerMD = cast_or_null<MDNode>(M.getModuleFlag(ValVerKey))) {
-    auto ValVer = loadDXILValidatorVersion(ValVerMD);
+  if (NamedMDNode *ValVerMD = M.getNamedMetadata(ValVerKey)) {
+    VersionTuple ValVer = loadDXILValidatorVersion(ValVerMD->getOperand(0));
     if (!ValVer.empty())
       ValidatorVer = ValVer;
   }
   emitDXILValidatorVersion(M, ValidatorVer);
-  cleanModule(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/dxil_ver.ll

 ; RUN: opt -S -dxil-metadata-emit < %s | FileCheck %s
 target datalayout = "e-m:e-p:32:32-i1:32-i8:8-i16:16-i32:32-i64:64-f16:16-f32:32-f64:64-n8:16:32:64"
 target triple = "dxil-pc-shadermodel6.3-library"
 
 ; Make sure dx.valver metadata is generated.
-; CHECK:!dx.valver = !{![[valver:[0-9]+]]}
+; CHECK-DAG:!dx.valver = !{![[valver:[0-9]+]]}
 ; Make sure module flags still exist and only have 1 operand left.
-; CHECK:!llvm.module.flags = !{{{![0-9]}}}
+; CHECK-DAG:!llvm.module.flags = !{{{![0-9]}}}
 ; Make sure validator version is 1.1.
-; CHECK:![[valver]] = !{i32 1, i32 1}
+; CHECK-DAG:![[valver]] = !{i32 1, i32 1}
 ; Make sure wchar_size still exist.
-; CHECK:!{i32 1, !"wchar_size", i32 4}
+; CHECK-DAG:!{i32 1, !"wchar_size", i32 4}
 
-!llvm.module.flags = !{!0, !1}
-!llvm.ident = !{!3}
+!llvm.module.flags = !{!0}
+!dx.valver = !{!1}
+!llvm.ident = !{!2}
 
 !0 = !{i32 1, !"wchar_size", i32 4}
-!1 = !{i32 6, !"dx.valver", !2}
-!2 = !{i32 1, i32 1}
-!3 = !{!"clang version 15.0.0 (https://github.com/llvm/llvm-project 71de12113a0661649ecb2f533fba4a2818a1ad68)"}
+!1 = !{i32 1, i32 1}
+!2 = !{!"clang version 15.0.0 (https://github.com/llvm/llvm-project 71de12113a0661649ecb2f533fba4a2818a1ad68)"}