1 //===-- EHContGuardCatchret.cpp - Catchret target symbols -------*- C++ -*-===// 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 /// \file 10 /// This file contains a machine function pass to insert a symbol before each 11 /// valid catchret target and store this in the MachineFunction's 12 /// CatchRetTargets vector. This will be used to emit the table of valid targets 13 /// used by EHCont Guard. 14 /// 15 //===----------------------------------------------------------------------===// 16 17 #include "llvm/ADT/Statistic.h" 18 #include "llvm/CodeGen/MachineBasicBlock.h" 19 #include "llvm/CodeGen/MachineFunctionPass.h" 20 #include "llvm/CodeGen/MachineInstr.h" 21 #include "llvm/CodeGen/MachineModuleInfo.h" 22 #include "llvm/CodeGen/MachineOperand.h" 23 #include "llvm/CodeGen/Passes.h" 24 #include "llvm/InitializePasses.h" 25 26 using namespace llvm; 27 28 #define DEBUG_TYPE "ehcontguard-catchret" 29 30 STATISTIC(EHContGuardCatchretTargets, 31 "Number of EHCont Guard catchret targets"); 32 33 namespace { 34 35 /// MachineFunction pass to insert a symbol before each valid catchret target 36 /// and store these in the MachineFunction's CatchRetTargets vector. 37 class EHContGuardCatchret : public MachineFunctionPass { 38 public: 39 static char ID; 40 41 EHContGuardCatchret() : MachineFunctionPass(ID) { 42 initializeEHContGuardCatchretPass(*PassRegistry::getPassRegistry()); 43 } 44 45 StringRef getPassName() const override { 46 return "EH Cont Guard catchret targets"; 47 } 48 49 bool runOnMachineFunction(MachineFunction &MF) override; 50 }; 51 52 } // end anonymous namespace 53 54 char EHContGuardCatchret::ID = 0; 55 56 INITIALIZE_PASS(EHContGuardCatchret, "EHContGuardCatchret", 57 "Insert symbols at valid catchret targets for /guard:ehcont", 58 false, false) 59 FunctionPass *llvm::createEHContGuardCatchretPass() { 60 return new EHContGuardCatchret(); 61 } 62 63 bool EHContGuardCatchret::runOnMachineFunction(MachineFunction &MF) { 64 65 // Skip modules for which the ehcontguard flag is not set. 66 if (!MF.getMMI().getModule()->getModuleFlag("ehcontguard")) 67 return false; 68 69 // Skip functions that do not have catchret 70 if (!MF.hasEHCatchret()) 71 return false; 72 73 bool Result = false; 74 75 for (MachineBasicBlock &MBB : MF) { 76 if (MBB.isEHCatchretTarget()) { 77 MF.addCatchretTarget(MBB.getEHCatchretSymbol()); 78 EHContGuardCatchretTargets++; 79 Result = true; 80 } 81 } 82 83 return Result; 84 } 85