llvm/llvm/lib/Target/X86/X86WinFixupBufferSecurityCheck.cpp

//===- X86WinFixupBufferSecurityCheck.cpp Fix Buffer Security Check Call -===//
//
// 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
//
//===----------------------------------------------------------------------===//
// Buffer Security Check implementation inserts windows specific callback into
// code. On windows, __security_check_cookie call gets call everytime function
// is return without fixup. Since this function is defined in runtime library,
// it incures cost of call in dll which simply does comparison and returns most
// time. With Fixup, We selective move to call in DLL only if comparison fails.
//===----------------------------------------------------------------------===//

#include "X86.h"
#include "X86FrameLowering.h"
#include "X86InstrInfo.h"
#include "X86Subtarget.h"
#include "llvm/CodeGen/LivePhysRegs.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/IR/Module.h"
#include <iterator>

usingnamespacellvm;

#define DEBUG_TYPE …

namespace {

class X86WinFixupBufferSecurityCheckPass : public MachineFunctionPass { … };
} // end anonymous namespace

char X86WinFixupBufferSecurityCheckPass::ID = …;

INITIALIZE_PASS(…)

FunctionPass *llvm::createX86WinFixupBufferSecurityCheckPass() { … }

void X86WinFixupBufferSecurityCheckPass::SplitBasicBlock(
    MachineBasicBlock *CurMBB, MachineBasicBlock *NewRetMBB,
    MachineBasicBlock::iterator SplitIt) { … }

std::pair<MachineBasicBlock *, MachineInstr *>
X86WinFixupBufferSecurityCheckPass::getSecurityCheckerBasicBlock(
    MachineFunction &MF) { … }

void X86WinFixupBufferSecurityCheckPass::getGuardCheckSequence(
    MachineBasicBlock *CurMBB, MachineInstr *CheckCall,
    MachineInstr *SeqMI[5]) { … }

std::pair<MachineInstr *, MachineInstr *>
X86WinFixupBufferSecurityCheckPass::CreateFailCheckSequence(
    MachineBasicBlock *CurMBB, MachineBasicBlock *FailMBB,
    MachineInstr *SeqMI[5]) { … }

void X86WinFixupBufferSecurityCheckPass::FinishBlock(MachineBasicBlock *MBB) { … }

void X86WinFixupBufferSecurityCheckPass::FinishFunction(
    MachineBasicBlock *FailMBB, MachineBasicBlock *NewRetMBB) { … }

bool X86WinFixupBufferSecurityCheckPass::runOnMachineFunction(
    MachineFunction &MF) { … }