llvm/llvm/lib/Target/AArch64/AArch64BranchTargets.cpp

//===-- AArch64BranchTargets.cpp -- Harden code using v8.5-A BTI extension -==//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This pass inserts BTI instructions at the start of every function and basic
// block which could be indirectly called. The hardware will (when enabled)
// trap when an indirect branch or call instruction targets an instruction
// which is not a valid BTI instruction. This is intended to guard against
// control-flow hijacking attacks. Note that this does not do anything for RET
// instructions, as they can be more precisely protected by return address
// signing.
//
//===----------------------------------------------------------------------===//

#include "AArch64MachineFunctionInfo.h"
#include "AArch64Subtarget.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/Support/Debug.h"

usingnamespacellvm;

#define DEBUG_TYPE …
#define AARCH64_BRANCH_TARGETS_NAME …

namespace {
class AArch64BranchTargets : public MachineFunctionPass { … };
} // end anonymous namespace

char AArch64BranchTargets::ID = …;

INITIALIZE_PASS(…)

void AArch64BranchTargets::getAnalysisUsage(AnalysisUsage &AU) const { … }

FunctionPass *llvm::createAArch64BranchTargetsPass() { … }

bool AArch64BranchTargets::runOnMachineFunction(MachineFunction &MF) { … }

void AArch64BranchTargets::addBTI(MachineBasicBlock &MBB, bool CouldCall,
                                  bool CouldJump, bool HasWinCFI) { … }