[Debugify] Mark mir-check-debugify change nothing of input

[xiangzhangllvm]

llvm/lib/CodeGen/MachineCheckDebugify.cpp

109

LGTM, Preserves All analysis is more reasonable.

[pengfei]

LGTM.

llvm/lib/CodeGen/MachineCheckDebugify.cpp

30–31

By the way, I think it's better to move it below the check of NMD.

[skan]

Address review comments

llvm/lib/CodeGen/MachineCheckDebugify.cpp

 //===- MachineCheckDebugify.cpp - Check debug info ------------------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 ///

 #define DEBUG_TYPE "mir-check-debugify"
 
 using namespace llvm;
 
 namespace {
 
 struct CheckDebugMachineModule : public ModulePass {
   bool runOnModule(Module &M) override {
     MachineModuleInfo &MMI =
         getAnalysis<MachineModuleInfoWrapperPass>().getMMI();
 
     NamedMDNode *NMD = M.getNamedMetadata("llvm.mir.debugify");
     if (!NMD) {
       errs() << "WARNING: Please run mir-debugify to generate "
                 "llvm.mir.debugify metadata first.\n";
       return false;
     }
 
bool runOnModule(Module &M) override {
 
     return false;
   }
 
   CheckDebugMachineModule() : ModulePass(ID) {}
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.addRequired<MachineModuleInfoWrapperPass>();
-    AU.addPreserved<MachineModuleInfoWrapperPass>();
-    AU.setPreservesCFG();
+    AU.setPreservesAll();
   }
 
   static char ID; // Pass identification.
 };
 char CheckDebugMachineModule::ID = 0;
 
 } // end anonymous namespace
 
 INITIALIZE_PASS_BEGIN(CheckDebugMachineModule, DEBUG_TYPE,
                       "Machine Check Debug Module", false, false)
 INITIALIZE_PASS_END(CheckDebugMachineModule, DEBUG_TYPE,
                     "Machine Check Debug Module", false, false)
 
 ModulePass *llvm::createCheckDebugMachineModulePass() {
   return new CheckDebugMachineModule();
 }