FEntryInserter.cpp revision 360784 
1//===-- FEntryInsertion.cpp - Patchable prologues for LLVM -------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file edits function bodies to insert fentry calls.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/CodeGen/MachineFunction.h"
14#include "llvm/CodeGen/MachineFunctionPass.h"
15#include "llvm/CodeGen/MachineInstrBuilder.h"
16#include "llvm/CodeGen/Passes.h"
17#include "llvm/CodeGen/TargetFrameLowering.h"
18#include "llvm/CodeGen/TargetInstrInfo.h"
19#include "llvm/CodeGen/TargetSubtargetInfo.h"
20#include "llvm/IR/Function.h"
21#include "llvm/IR/Module.h"
22#include "llvm/InitializePasses.h"
23
24using namespace llvm;
25
26namespace {
27struct FEntryInserter : public MachineFunctionPass {
28  static char ID; // Pass identification, replacement for typeid
29  FEntryInserter() : MachineFunctionPass(ID) {
30    initializeFEntryInserterPass(*PassRegistry::getPassRegistry());
31  }
32
33  bool runOnMachineFunction(MachineFunction &F) override;
34};
35}
36
37bool FEntryInserter::runOnMachineFunction(MachineFunction &MF) {
38  const std::string FEntryName =
39      MF.getFunction().getFnAttribute("fentry-call").getValueAsString();
40  if (FEntryName != "true")
41    return false;
42
43  auto &FirstMBB = *MF.begin();
44  auto *TII = MF.getSubtarget().getInstrInfo();
45  BuildMI(FirstMBB, FirstMBB.begin(), DebugLoc(),
46          TII->get(TargetOpcode::FENTRY_CALL));
47  return true;
48}
49
50char FEntryInserter::ID = 0;
51char &llvm::FEntryInserterID = FEntryInserter::ID;
52INITIALIZE_PASS(FEntryInserter, "fentry-insert", "Insert fentry calls", false,
53                false)
54