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diff --git a/llvm/lib/Target/X86/X86IndirectBranchTracking.cpp b/llvm/lib/Target/X86/X86IndirectBranchTracking.cpp
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+++ b/llvm/lib/Target/X86/X86IndirectBranchTracking.cpp
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+//===---- X86IndirectBranchTracking.cpp - Enables CET IBT mechanism -------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// 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 "llvm/ADT/Statistic.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineJumpTableInfo.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;
+
+  /// Endbr opcode for the current machine function.
+  unsigned int EndbrOpcode;
+
+  /// The function looks for an indirect jump terminator in MBB predecessors.
+  ///
+  /// Jump tables are generated when lowering switch-case statements or
+  /// setjmp/longjump functions.
+  /// As a result only indirect jumps use jump tables.
+  /// The function verifies this assumption.
+  ///
+  /// \return true if the input \p MBB has a predecessor MBB with indirect
+  /// branch terminator or false otherwise.
+  bool verifyIndirectJump(const MachineBasicBlock *MBB) const;
+
+  /// Adds a new ENDBR instruction to the begining of the MBB.
+  /// The function will not add it if already exists.
+  /// It will add ENDBR32 or ENDBR64 opcode, depending on the target.
+  void addENDBR(MachineBasicBlock &MBB) const;
+};
+
+} // end anonymous namespace
+
+char X86IndirectBranchTrackingPass::ID = 0;
+
+FunctionPass *llvm::createX86IndirectBranchTrackingPass() {
+  return new X86IndirectBranchTrackingPass();
+}
+
+bool X86IndirectBranchTrackingPass::verifyIndirectJump(
+    const MachineBasicBlock *MBB) const {
+  for (auto &PredMBB : MBB->predecessors())
+    for (auto &TermI : PredMBB->terminators())
+      if (TermI.isIndirectBranch())
+        return true;
+
+  return false;
+}
+
+void X86IndirectBranchTrackingPass::addENDBR(MachineBasicBlock &MBB) const {
+  assert(TII && "Target instruction info was not initialized");
+  assert((X86::ENDBR64 == EndbrOpcode || X86::ENDBR32 == EndbrOpcode) &&
+         "Unexpected Endbr opcode");
+
+  auto MI = MBB.begin();
+  // If the MBB is empty or the first instruction is not ENDBR,
+  // add the ENDBR instruction to the beginning of the MBB.
+  if (MI == MBB.end() || EndbrOpcode != MI->getOpcode()) {
+    BuildMI(MBB, MI, MBB.findDebugLoc(MI), TII->get(EndbrOpcode));
+    NumEndBranchAdded++;
+  }
+}
+
+bool X86IndirectBranchTrackingPass::runOnMachineFunction(MachineFunction &MF) {
+  const X86Subtarget &SubTarget = MF.getSubtarget<X86Subtarget>();
+
+  // Make sure that the target supports ENDBR instruction.
+  if (!SubTarget.hasIBT())
+    return false;
+
+  // Check that the cf-protection-branch is enabled.
+  Metadata *isCFProtectionSupported =
+      MF.getMMI().getModule()->getModuleFlag("cf-protection-branch");
+  if (!isCFProtectionSupported && !IndirectBranchTracking)
+    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;
+
+  // Non-internal function or function whose address was taken, can be
+  // invoked through indirect calls. Mark the first BB with ENDBR instruction.
+  // TODO: Do not add ENDBR instruction in case notrack attribute is used.
+  if (MF.getFunction().hasAddressTaken() ||
+      !MF.getFunction().hasLocalLinkage()) {
+    auto MBB = MF.begin();
+    addENDBR(*MBB);
+    Changed = true;
+  }
+
+  for (auto &MBB : MF) {
+    // Find all basic blocks that thier address was taken (for example
+    // in the case of indirect jump) and add ENDBR instruction.
+    if (MBB.hasAddressTaken()) {
+      addENDBR(MBB);
+      Changed = true;
+    }
+  }
+
+  // Adds ENDBR instructions to MBB destinations of the jump table.
+  // TODO: In case of more than 50 destinations, do not add ENDBR and
+  // instead add DS_PREFIX.
+  if (MachineJumpTableInfo *JTI = MF.getJumpTableInfo()) {
+    for (const auto &JT : JTI->getJumpTables()) {
+      for (auto *MBB : JT.MBBs) {
+        // This assert verifies the assumption that this MBB has an indirect
+        // jump terminator in one of its predecessor.
+        assert(verifyIndirectJump(MBB) &&
+               "The MBB is not the destination of an indirect jump");
+
+        addENDBR(*MBB);
+        Changed = true;
+      }
+    }
+  }
+
+  return Changed;
+}