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//===-- EHContGuardTargets.cpp - EH continuation target symbols -*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file contains a machine function pass to insert a symbol before each
/// valid target where the unwinder in Windows may continue exectution after an
/// exception is thrown and store this in the MachineFunction's EHContTargets
/// vector. This will be used to emit the table of valid targets used by Windows
/// EH Continuation Guard.
///
//===----------------------------------------------------------------------===//
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/IR/Module.h"
#include "llvm/InitializePasses.h"
using namespace llvm;
#define DEBUG_TYPE "ehcontguard-catchret"
STATISTIC(EHContGuardTargetsFound, "Number of EHCont Guard targets");
namespace {
/// MachineFunction pass to insert a symbol before each valid catchret target
/// and store these in the MachineFunction's CatchRetTargets vector.
class EHContGuardTargets : public MachineFunctionPass {
public:
static char ID;
EHContGuardTargets() : MachineFunctionPass(ID) {
initializeEHContGuardTargetsPass(*PassRegistry::getPassRegistry());
}
StringRef getPassName() const override {
return "EH Cont Guard catchret targets";
}
bool runOnMachineFunction(MachineFunction &MF) override;
};
} // end anonymous namespace
char EHContGuardTargets::ID = 0;
INITIALIZE_PASS(EHContGuardTargets, "EHContGuardTargets",
"Insert symbols at valid targets for /guard:ehcont", false,
false)
FunctionPass *llvm::createEHContGuardTargetsPass() {
return new EHContGuardTargets();
}
bool EHContGuardTargets::runOnMachineFunction(MachineFunction &MF) {
// Skip modules for which the ehcontguard flag is not set.
if (!MF.getFunction().getParent()->getModuleFlag("ehcontguard"))
return false;
// Skip functions that do not have targets
if (!MF.hasEHContTarget())
return false;
bool Result = false;
for (MachineBasicBlock &MBB : MF) {
if (MBB.isEHContTarget()) {
MF.addEHContTarget(MBB.getEHContSymbol());
EHContGuardTargetsFound++;
Result = true;
}
}
return Result;
}
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