| 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(Key: "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(Target: MBB.getEHCatchretSymbol()); |
| 76 | EHContGuardCatchretTargets++; |
| 77 | Result = true; |
| 78 | } |
| 79 | } |
| 80 | |
| 81 | return Result; |
| 82 | } |
| 83 |