[llvm] Add a pass to calculate machine function's cfg hash to detect whether… (PR #84145)

[Rahman Lavaee via llvm-commits]

================
@@ -0,0 +1,57 @@
+//===-- MachineFunctionHashBuilder.h ----------------------------------*-
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the implementation of pass about calculating machine
+/// function hash.
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_MACHINE_FUNCTION_HASH_BUILDER_H
+#define LLVM_MACHINE_FUNCTION_HASH_BUILDER_H
+
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/InitializePasses.h"
+
+namespace llvm {
+
+class MachineFunctionHashBuilder : public MachineFunctionPass {
+public:
+  static char ID;
+
+  MachineFunctionHashBuilder() : MachineFunctionPass(ID) {
+    initializeMachineFunctionHashBuilderPass(*PassRegistry::getPassRegistry());
+  }
+
+  StringRef getPassName() const override {
+    return "Calculate machine function hash.";
+  }
+
+  bool runOnMachineFunction(MachineFunction &MF) override;
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.setPreservesAll();
+    MachineFunctionPass::getAnalysisUsage(AU);
+  }
+
+  uint64_t getCFGHash(StringRef Name) {
+    if (!CFGHash.count(Name)) {
----------------
rlavaee wrote:

`return CFGHash.lookup(Name);`

https://github.com/llvm/llvm-project/pull/84145