File Manager

003 File Manager

Current Path: /usr/src/contrib/llvm-project/llvm/lib/Target/X86

usr / src / contrib / llvm-project / llvm / lib / Target / X86 /

📁 ..
📁 AsmParser
📁 Disassembler
📄 ImmutableGraph.h(15.15 KB)
📁 MCTargetDesc
📁 TargetInfo
📄 X86.h(7.41 KB)
📄 X86.td(68.44 KB)
📄 X86AsmPrinter.cpp(27.18 KB)
📄 X86AsmPrinter.h(5.96 KB)
📄 X86AvoidStoreForwardingBlocks.cpp(27.94 KB)
📄 X86AvoidTrailingCall.cpp(4.91 KB)
📄 X86CallFrameOptimization.cpp(23.07 KB)
📄 X86CallLowering.cpp(17.62 KB)
📄 X86CallLowering.h(1.74 KB)
📄 X86CallingConv.cpp(13.34 KB)
📄 X86CallingConv.h(1.09 KB)
📄 X86CallingConv.td(46.15 KB)
📄 X86CmovConversion.cpp(34.07 KB)
📄 X86CondBrFolding.cpp(18.4 KB)
📄 X86DiscriminateMemOps.cpp(7.11 KB)
📄 X86DomainReassignment.cpp(25.87 KB)
📄 X86EvexToVex.cpp(8.8 KB)
📄 X86ExpandPseudo.cpp(16.95 KB)
📄 X86FastISel.cpp(139.28 KB)
📄 X86FixupBWInsts.cpp(18.09 KB)
📄 X86FixupLEAs.cpp(24.44 KB)
📄 X86FixupSetCC.cpp(4.44 KB)
📄 X86FlagsCopyLowering.cpp(40.36 KB)
📄 X86FloatingPoint.cpp(62.66 KB)
📄 X86FrameLowering.cpp(138.71 KB)
📄 X86FrameLowering.h(11.64 KB)
📄 X86GenRegisterBankInfo.def(3.32 KB)
📄 X86ISelDAGToDAG.cpp(208.37 KB)
📄 X86ISelLowering.cpp(1.94 MB)
📄 X86ISelLowering.h(60.88 KB)
📄 X86IndirectBranchTracking.cpp(6.17 KB)
📄 X86IndirectThunks.cpp(9.78 KB)
📄 X86InsertPrefetch.cpp(9.64 KB)
📄 X86InsertWait.cpp(4.47 KB)
📄 X86Instr3DNow.td(5.24 KB)
📄 X86InstrAMX.td(5.6 KB)
📄 X86InstrAVX512.td(653.76 KB)
📄 X86InstrArithmetic.td(75.61 KB)
📄 X86InstrBuilder.h(8.45 KB)
📄 X86InstrCMovSetCC.td(5.76 KB)
📄 X86InstrCompiler.td(95.78 KB)
📄 X86InstrControl.td(20.53 KB)
📄 X86InstrExtension.td(11.64 KB)
📄 X86InstrFMA.td(33.23 KB)
📄 X86InstrFMA3Info.cpp(6.21 KB)
📄 X86InstrFMA3Info.h(3.25 KB)
📄 X86InstrFPStack.td(39.52 KB)
📄 X86InstrFoldTables.cpp(393.01 KB)
📄 X86InstrFoldTables.h(3.03 KB)
📄 X86InstrFormats.td(41.05 KB)
📄 X86InstrFragmentsSIMD.td(61.14 KB)
📄 X86InstrInfo.cpp(322.72 KB)
📄 X86InstrInfo.h(29.34 KB)
📄 X86InstrInfo.td(169.76 KB)
📄 X86InstrMMX.td(29.55 KB)
📄 X86InstrMPX.td(3.63 KB)
📄 X86InstrSGX.td(1.12 KB)
📄 X86InstrSSE.td(385.01 KB)
📄 X86InstrSVM.td(2.16 KB)
📄 X86InstrShiftRotate.td(49.56 KB)
📄 X86InstrSystem.td(34.03 KB)
📄 X86InstrTSX.td(2.1 KB)
📄 X86InstrVMX.td(3.53 KB)
📄 X86InstrVecCompiler.td(21.09 KB)
📄 X86InstrXOP.td(23.81 KB)
📄 X86InstructionSelector.cpp(61.11 KB)
📄 X86InterleavedAccess.cpp(32.7 KB)
📄 X86IntrinsicsInfo.h(73.96 KB)
📄 X86LegalizerInfo.cpp(15.6 KB)
📄 X86LegalizerInfo.h(1.65 KB)
📄 X86LoadValueInjectionLoadHardening.cpp(32.4 KB)
📄 X86LoadValueInjectionRetHardening.cpp(4.93 KB)
📄 X86MCInstLower.cpp(96.53 KB)
📄 X86MachineFunctionInfo.cpp(1.1 KB)
📄 X86MachineFunctionInfo.h(8.87 KB)
📄 X86MacroFusion.cpp(2.62 KB)
📄 X86MacroFusion.h(992 B)
📄 X86OptimizeLEAs.cpp(27.47 KB)
📄 X86PadShortFunction.cpp(7.33 KB)
📄 X86PartialReduction.cpp(15.46 KB)
📄 X86PfmCounters.td(10.18 KB)
📄 X86RegisterBankInfo.cpp(10.55 KB)
📄 X86RegisterBankInfo.h(2.87 KB)
📄 X86RegisterBanks.td(629 B)
📄 X86RegisterInfo.cpp(29 KB)
📄 X86RegisterInfo.h(5.61 KB)
📄 X86RegisterInfo.td(26.07 KB)
📄 X86SchedBroadwell.td(69.45 KB)
📄 X86SchedHaswell.td(73.96 KB)
📄 X86SchedPredicates.td(4.23 KB)
📄 X86SchedSandyBridge.td(50 KB)
📄 X86SchedSkylakeClient.td(74.65 KB)
📄 X86SchedSkylakeServer.td(113.85 KB)
📄 X86Schedule.td(36.9 KB)
📄 X86ScheduleAtom.td(38.26 KB)
📄 X86ScheduleBdVer2.td(56.78 KB)
📄 X86ScheduleBtVer2.td(46.98 KB)
📄 X86ScheduleSLM.td(22.91 KB)
📄 X86ScheduleZnver1.td(48.97 KB)
📄 X86ScheduleZnver2.td(48.12 KB)
📄 X86SelectionDAGInfo.cpp(12.02 KB)
📄 X86SelectionDAGInfo.h(1.8 KB)
📄 X86ShuffleDecodeConstantPool.cpp(11.22 KB)
📄 X86ShuffleDecodeConstantPool.h(2.13 KB)
📄 X86SpeculativeExecutionSideEffectSuppression.cpp(6.97 KB)
📄 X86SpeculativeLoadHardening.cpp(93.16 KB)
📄 X86Subtarget.cpp(13.25 KB)
📄 X86Subtarget.h(32.08 KB)
📄 X86TargetMachine.cpp(18.88 KB)
📄 X86TargetMachine.h(2.04 KB)
📄 X86TargetObjectFile.cpp(2.61 KB)
📄 X86TargetObjectFile.h(2.13 KB)
📄 X86TargetTransformInfo.cpp(189.14 KB)
📄 X86TargetTransformInfo.h(9.63 KB)
📄 X86VZeroUpper.cpp(12.59 KB)
📄 X86WinAllocaExpander.cpp(9.54 KB)
📄 X86WinEHState.cpp(28.97 KB)

Editing: X86IndirectBranchTracking.cpp

//===---- X86IndirectBranchTracking.cpp - Enables CET IBT mechanism -------===//
//
// 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 file defines a pass that enables Indirect Branch Tracking (IBT) as part
// of Control-Flow Enforcement Technology (CET).
// The pass adds ENDBR (End Branch) machine instructions at the beginning of
// each basic block or function that is referenced by an indrect jump/call
// instruction.
// The ENDBR instructions have a NOP encoding and as such are ignored in
// targets that do not support CET IBT mechanism.
//===----------------------------------------------------------------------===//

#include "X86.h"
#include "X86InstrInfo.h"
#include "X86Subtarget.h"
#include "X86TargetMachine.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineModuleInfo.h"

using namespace llvm;

#define DEBUG_TYPE "x86-indirect-branch-tracking"

static cl::opt<bool> IndirectBranchTracking(
    "x86-indirect-branch-tracking", cl::init(false), cl::Hidden,
    cl::desc("Enable X86 indirect branch tracking pass."));

STATISTIC(NumEndBranchAdded, "Number of ENDBR instructions added");

namespace {
class X86IndirectBranchTrackingPass : public MachineFunctionPass {
public:
  X86IndirectBranchTrackingPass() : MachineFunctionPass(ID) {}

StringRef getPassName() const override {
    return "X86 Indirect Branch Tracking";
  }

bool runOnMachineFunction(MachineFunction &MF) override;

private:
  static char ID;

/// Machine instruction info used throughout the class.
  const X86InstrInfo *TII = nullptr;

/// Endbr opcode for the current machine function.
  unsigned int EndbrOpcode = 0;

/// Adds a new ENDBR instruction to the beginning of the MBB.
  /// The function will not add it if already exists.
  /// It will add ENDBR32 or ENDBR64 opcode, depending on the target.
  /// \returns true if the ENDBR was added and false otherwise.
  bool addENDBR(MachineBasicBlock &MBB, MachineBasicBlock::iterator I) const;
};

} // end anonymous namespace

char X86IndirectBranchTrackingPass::ID = 0;

FunctionPass *llvm::createX86IndirectBranchTrackingPass() {
  return new X86IndirectBranchTrackingPass();
}

bool X86IndirectBranchTrackingPass::addENDBR(
    MachineBasicBlock &MBB, MachineBasicBlock::iterator I) const {
  assert(TII && "Target instruction info was not initialized");
  assert((X86::ENDBR64 == EndbrOpcode || X86::ENDBR32 == EndbrOpcode) &&
         "Unexpected Endbr opcode");

// If the MBB/I is empty or the current instruction is not ENDBR,
  // insert ENDBR instruction to the location of I.
  if (I == MBB.end() || I->getOpcode() != EndbrOpcode) {
    BuildMI(MBB, I, MBB.findDebugLoc(I), TII->get(EndbrOpcode));
    ++NumEndBranchAdded;
    return true;
  }
  return false;
}

static bool IsCallReturnTwice(llvm::MachineOperand &MOp) {
  if (!MOp.isGlobal())
    return false;
  auto *CalleeFn = dyn_cast<Function>(MOp.getGlobal());
  if (!CalleeFn)
    return false;
  AttributeList Attrs = CalleeFn->getAttributes();
  return Attrs.hasFnAttribute(Attribute::ReturnsTwice);
}

bool X86IndirectBranchTrackingPass::runOnMachineFunction(MachineFunction &MF) {
  const X86Subtarget &SubTarget = MF.getSubtarget<X86Subtarget>();

// Check that the cf-protection-branch is enabled.
  Metadata *isCFProtectionSupported =
      MF.getMMI().getModule()->getModuleFlag("cf-protection-branch");
  // NB: We need to enable IBT in jitted code if JIT compiler is CET
  // enabled.
  const X86TargetMachine *TM =
      static_cast<const X86TargetMachine *>(&MF.getTarget());
#ifdef __CET__
  bool isJITwithCET = TM->isJIT();
#else
  bool isJITwithCET = false;
#endif
  if (!isCFProtectionSupported && !IndirectBranchTracking && !isJITwithCET)
    return false;

// True if the current MF was changed and false otherwise.
  bool Changed = false;

TII = SubTarget.getInstrInfo();
  EndbrOpcode = SubTarget.is64Bit() ? X86::ENDBR64 : X86::ENDBR32;

// Large code model, non-internal function or function whose address
  // was taken, can be accessed through indirect calls. Mark the first
  // BB with ENDBR instruction unless nocf_check attribute is used.
  if ((TM->getCodeModel() == CodeModel::Large ||
       MF.getFunction().hasAddressTaken() ||
       !MF.getFunction().hasLocalLinkage()) &&
      !MF.getFunction().doesNoCfCheck()) {
    auto MBB = MF.begin();
    Changed |= addENDBR(*MBB, MBB->begin());
  }

for (auto &MBB : MF) {
    // Find all basic blocks that their address was taken (for example
    // in the case of indirect jump) and add ENDBR instruction.
    if (MBB.hasAddressTaken())
      Changed |= addENDBR(MBB, MBB.begin());

for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end(); ++I) {
      if (I->isCall() && IsCallReturnTwice(I->getOperand(0)))
        Changed |= addENDBR(MBB, std::next(I));
    }

// Exception handle may indirectly jump to catch pad, So we should add
    // ENDBR before catch pad instructions. For SjLj exception model, it will
    // create a new BB(new landingpad) indirectly jump to the old landingpad.
    if (TM->Options.ExceptionModel == ExceptionHandling::SjLj) {
      for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end(); ++I) {
        // New Landingpad BB without EHLabel.
        if (MBB.isEHPad()) {
          if (I->isDebugInstr())
            continue;
          Changed |= addENDBR(MBB, I);
          break;
        } else if (I->isEHLabel()) {
          // Old Landingpad BB (is not Landingpad now) with
          // the the old "callee" EHLabel.
          MCSymbol *Sym = I->getOperand(0).getMCSymbol();
          if (!MF.hasCallSiteLandingPad(Sym))
            continue;
          Changed |= addENDBR(MBB, std::next(I));
          break;
        }
      }
    } else if (MBB.isEHPad()){
      for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end(); ++I) {
        if (!I->isEHLabel())
          continue;
        Changed |= addENDBR(MBB, std::next(I));
        break;
      }
    }
  }
  return Changed;
}

003 File Manager

Editing: X86IndirectBranchTracking.cpp

Upload File

Create Folder