[DirectX backend] When cleanup module flags only remove unused flags.

[python3kgae]

Summary

Only remove dx.valver from module flags when cleanup module flags in DXILTranslateMetadataPass.

[beanz]

llvm/test/CodeGen/DirectX/dxil_ver.ll

8

You should verify that the module flags array only has one element.

[python3kgae]

Update test to make sure only 1 operand left for module flags.

[beanz]

LGTM.

llvm/lib/Target/DirectX/DXILTranslateMetadata.cpp

 //===- DXILTranslateMetadata.cpp - Pass to emit DXIL metadata ---*- C++ -*-===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 ///
 //===----------------------------------------------------------------------===//
 
 #include "DirectX.h"
+#include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/Metadata.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Pass.h"
 
 using namespace llvm;
 
 static uint32_t ConstMDToUint32(const MDOperand &MDO) {
   ConstantInt *pConst = mdconst::extract<ConstantInt>(MDO);
   return (uint32_t)pConst->getZExtValue();
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 cleanModule(Module &M) {
-  M.getOrInsertModuleFlagsMetadata()->eraseFromParent();
+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"; }

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]+]]}
+; Make sure module flags still exist and only have 1 operand left.
+; CHECK:!llvm.module.flags = !{{{![0-9]}}}
+; Make sure validator version is 1.1.
 ; CHECK:![[valver]] = !{i32 1, i32 1}
+; Make sure wchar_size still exist.
+; CHECK:!{i32 1, !"wchar_size", i32 4}
 
 !llvm.module.flags = !{!0, !1}
 !llvm.ident = !{!3}
 
 !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)"}