llvm/lib/CodeGen/FEntryInserter.cpp

   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/TargetInstrInfo.h"
  17 #include "llvm/CodeGen/TargetSubtargetInfo.h"
  18 #include "llvm/IR/Function.h"
  19 #include "llvm/InitializePasses.h"
  20
  21 using namespace llvm;
  22
  23 namespace {
  24 struct FEntryInserter : public MachineFunctionPass {
  25   static char ID; // Pass identification, replacement for typeid
  26   FEntryInserter() : MachineFunctionPass(ID) {
  27     initializeFEntryInserterPass(*PassRegistry::getPassRegistry());
  28   }
  29
  30   bool runOnMachineFunction(MachineFunction &F) override;
  31 };
  32 }
  33
  34 bool FEntryInserter::runOnMachineFunction(MachineFunction &MF) {
  35   const std::string FEntryName = std::string(
  36       MF.getFunction().getFnAttribute("fentry-call").getValueAsString());
  37   if (FEntryName != "true")
  38     return false;
  39
  40   auto &FirstMBB = *MF.begin();
  41   auto *TII = MF.getSubtarget().getInstrInfo();
  42   BuildMI(FirstMBB, FirstMBB.begin(), DebugLoc(),
  43           TII->get(TargetOpcode::FENTRY_CALL));
  44   return true;
  45 }
  46
  47 char FEntryInserter::ID = 0;
  48 char &llvm::FEntryInserterID = FEntryInserter::ID;
  49 INITIALIZE_PASS(FEntryInserter, "fentry-insert", "Insert fentry calls", false,
  50                 false)