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