MFC r309124:

Upgrade our copies of clang, llvm, lldb, compiler-rt and libc++ to 3.9.0
release, and add lld 3.9.0.  Also completely revamp the build system for
clang, llvm, lldb and their related tools.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Release notes for llvm, clang and lld are available here:
<http://llvm.org/releases/3.9.0/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.9.0/tools/clang/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.9.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Bryan Drewery, Andrew Turner, Antoine Brodin and Jan
Beich for their help.

Relnotes:	yes

MFC r309147:

Pull in r282174 from upstream llvm trunk (by Krzysztof Parzyszek):

  [PPC] Set SP after loading data from stack frame, if no red zone is
  present

  Follow-up to r280705: Make sure that the SP is only restored after
  all data is loaded from the stack frame, if there is no red zone.

  This completes the fix for
  https://llvm.org/bugs/show_bug.cgi?id=26519.

  Differential Revision: https://reviews.llvm.org/D24466

Reported by:    Mark Millard
PR:             214433

MFC r309149:

Pull in r283060 from upstream llvm trunk (by Hal Finkel):

  [PowerPC] Refactor soft-float support, and enable PPC64 soft float

  This change enables soft-float for PowerPC64, and also makes
  soft-float disable all vector instruction sets for both 32-bit and
  64-bit modes. This latter part is necessary because the PPC backend
  canonicalizes many Altivec vector types to floating-point types, and
  so soft-float breaks scalarization support for many operations. Both
  for embedded targets and for operating-system kernels desiring
  soft-float support, it seems reasonable that disabling hardware
  floating-point also disables vector instructions (embedded targets
  without hardware floating point support are unlikely to have Altivec,
  etc. and operating system kernels desiring not to use floating-point
  registers to lower syscall cost are unlikely to want to use vector
  registers either). If someone needs this to work, we'll need to
  change the fact that we promote many Altivec operations to act on
  v4f32. To make it possible to disable Altivec when soft-float is
  enabled, hardware floating-point support needs to be expressed as a
  positive feature, like the others, and not a negative feature,
  because target features cannot have dependencies on the disabling of
  some other feature. So +soft-float has now become -hard-float.

  Fixes PR26970.

Pull in r283061 from upstream clang trunk (by Hal Finkel):

  [PowerPC] Enable soft-float for PPC64, and +soft-float -> -hard-float

  Enable soft-float support on PPC64, as the backend now supports it.
  Also, the backend now uses -hard-float instead of +soft-float, so set
  the target features accordingly.

  Fixes PR26970.

Reported by:	Mark Millard
PR:		214433

MFC r309212:

Add a few missed clang 3.9.0 files to OptionalObsoleteFiles.

MFC r309262:

Fix packaging for clang, lldb and lld 3.9.0

During the upgrade of clang/llvm etc to 3.9.0 in r309124, the PACKAGE
directive in the usr.bin/clang/*.mk files got dropped accidentally.

Restore it, with a few minor changes and additions:
* Correct license in clang.ucl to NCSA
* Add PACKAGE=clang for clang and most of the "ll" tools
* Put lldb in its own package
* Put lld in its own package

Reviewed by:	gjb, jmallett
Differential Revision: https://reviews.freebsd.org/D8666

MFC r309656:

During the bootstrap phase, when building the minimal llvm library on
PowerPC, add lib/Support/Atomic.cpp.  This is needed because upstream
llvm revision r271821 disabled the use of std::call_once, which causes
some fallback functions from Atomic.cpp to be used instead.

Reported by:	Mark Millard
PR:		214902

MFC r309835:

Tentatively apply https://reviews.llvm.org/D18730 to work around gcc PR
70528 (bogus error: constructor required before non-static data member).
This should fix buildworld with the external gcc package.

Reported by:	https://jenkins.freebsd.org/job/FreeBSD_HEAD_amd64_gcc/

MFC r310194:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
3.9.1 release.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/3.9.1/docs/ReleaseNotes.html>
<http://releases.llvm.org/3.9.1/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/3.9.1/tools/lld/docs/ReleaseNotes.html>

Relnotes:	yes

1 files changed, 0 insertions, 1066 deletions

diff --git a/contrib/llvm/lib/Target/WebAssembly/WebAssemblyPEI.cpp b/contrib/llvm/lib/Target/WebAssembly/WebAssemblyPEI.cpp
deleted file mode 100644
index d570d42..0000000
--- a/contrib/llvm/lib/Target/WebAssembly/WebAssemblyPEI.cpp
+++ /dev/null
@@ -1,1066 +0,0 @@
-//===-- WebAssemblyPEI.cpp - Insert Prolog/Epilog code in function --===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass is responsible for finalizing the functions frame layout, saving
-// callee saved registers, and for emitting prolog & epilog code for the
-// function.
-//
-// This pass must be run after register allocation.  After this pass is
-// executed, it is illegal to construct MO_FrameIndex operands.
-//
-// This is a copy of lib/CodeGen/PrologEpilogInserter.cpp except that it does
-// not assert that all virtual registers are gone (because WebAssembly currently
-// uses virtual rather than physical registers), and only runs
-// MRI.clearVirtRegs() if scavenging happened (which it never does). It also
-// uses a different class name so it can be registered via INITIALIZE_PASS.
-// It is otherwise unmodified, so any changes to the target-independent PEI
-// can be easily applied.
-//===----------------------------------------------------------------------===//
-
-#include "llvm/ADT/IndexedMap.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/SetVector.h"
-#include "llvm/ADT/SmallSet.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/CodeGen/MachineDominators.h"
-#include "llvm/CodeGen/MachineFrameInfo.h"
-#include "llvm/CodeGen/MachineInstr.h"
-#include "llvm/CodeGen/MachineLoopInfo.h"
-#include "llvm/CodeGen/MachineModuleInfo.h"
-#include "llvm/CodeGen/MachineRegisterInfo.h"
-#include "llvm/CodeGen/Passes.h"
-#include "llvm/CodeGen/RegisterScavenging.h"
-#include "llvm/CodeGen/StackProtector.h"
-#include "llvm/CodeGen/WinEHFuncInfo.h"
-#include "llvm/IR/DiagnosticInfo.h"
-#include "llvm/IR/InlineAsm.h"
-#include "llvm/IR/LLVMContext.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Compiler.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Target/TargetFrameLowering.h"
-#include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/Target/TargetMachine.h"
-#include "llvm/Target/TargetRegisterInfo.h"
-#include "llvm/Target/TargetSubtargetInfo.h"
-#include <climits>
-
-using namespace llvm;
-
-#define DEBUG_TYPE "pei"
-namespace llvm {
-void initializeWasmPEIPass(PassRegistry&);
-}
-namespace {
-class WasmPEI : public MachineFunctionPass {
-public:
-  static char ID;
-  WasmPEI() : MachineFunctionPass(ID) {
-    initializeWasmPEIPass(*PassRegistry::getPassRegistry());
-  }
-
-  void getAnalysisUsage(AnalysisUsage &AU) const override;
-
-  /// runOnMachineFunction - Insert prolog/epilog code and replace abstract
-  /// frame indexes with appropriate references.
-  ///
-  bool runOnMachineFunction(MachineFunction &Fn) override;
-
-private:
-  RegScavenger *RS;
-
-  // MinCSFrameIndex, MaxCSFrameIndex - Keeps the range of callee saved
-  // stack frame indexes.
-  unsigned MinCSFrameIndex, MaxCSFrameIndex;
-
-  // Save and Restore blocks of the current function. Typically there is a
-  // single save block, unless Windows EH funclets are involved.
-  SmallVector<MachineBasicBlock *, 1> SaveBlocks;
-  SmallVector<MachineBasicBlock *, 4> RestoreBlocks;
-
-  // Flag to control whether to use the register scavenger to resolve
-  // frame index materialization registers. Set according to
-  // TRI->requiresFrameIndexScavenging() for the current function.
-  bool FrameIndexVirtualScavenging;
-
-  void calculateSets(MachineFunction &Fn);
-  void calculateCallsInformation(MachineFunction &Fn);
-  void assignCalleeSavedSpillSlots(MachineFunction &Fn,
-                                   const BitVector &SavedRegs);
-  void insertCSRSpillsAndRestores(MachineFunction &Fn);
-  void calculateFrameObjectOffsets(MachineFunction &Fn);
-  void replaceFrameIndices(MachineFunction &Fn);
-  void replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &Fn,
-                           int &SPAdj);
-  void scavengeFrameVirtualRegs(MachineFunction &Fn);
-  void insertPrologEpilogCode(MachineFunction &Fn);
-};
-} // namespace
-
-char WasmPEI::ID = 0;
-
-namespace llvm {
-FunctionPass *createWebAssemblyPEI() {
-  return new WasmPEI();
-}
-}
-
-static cl::opt<unsigned>
-WarnStackSize("wasm-warn-stack-size", cl::Hidden, cl::init((unsigned)-1),
-              cl::desc("Warn for stack size bigger than the given"
-                       " number"));
-
-INITIALIZE_PASS_BEGIN(WasmPEI, "wasmprologepilog",
-                "Wasm Prologue/Epilogue Insertion", false, false)
-INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
-INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
-INITIALIZE_PASS_DEPENDENCY(StackProtector)
-INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
-INITIALIZE_PASS_END(WasmPEI, "wasmprologepilog",
-                    "Wasm Prologue/Epilogue Insertion & Frame Finalization",
-                    false, false)
-
-STATISTIC(NumScavengedRegs, "Number of frame index regs scavenged");
-STATISTIC(NumBytesStackSpace,
-          "Number of bytes used for stack in all functions");
-
-void WasmPEI::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.setPreservesCFG();
-  AU.addPreserved<MachineLoopInfo>();
-  AU.addPreserved<MachineDominatorTree>();
-  AU.addRequired<StackProtector>();
-  AU.addRequired<TargetPassConfig>();
-  MachineFunctionPass::getAnalysisUsage(AU);
-}
-
-/// Compute the set of return blocks
-void WasmPEI::calculateSets(MachineFunction &Fn) {
-  const MachineFrameInfo *MFI = Fn.getFrameInfo();
-
-  // Even when we do not change any CSR, we still want to insert the
-  // prologue and epilogue of the function.
-  // So set the save points for those.
-
-  // Use the points found by shrink-wrapping, if any.
-  if (MFI->getSavePoint()) {
-    SaveBlocks.push_back(MFI->getSavePoint());
-    assert(MFI->getRestorePoint() && "Both restore and save must be set");
-    MachineBasicBlock *RestoreBlock = MFI->getRestorePoint();
-    // If RestoreBlock does not have any successor and is not a return block
-    // then the end point is unreachable and we do not need to insert any
-    // epilogue.
-    if (!RestoreBlock->succ_empty() || RestoreBlock->isReturnBlock())
-      RestoreBlocks.push_back(RestoreBlock);
-    return;
-  }
-
-  // Save refs to entry and return blocks.
-  SaveBlocks.push_back(&Fn.front());
-  for (MachineBasicBlock &MBB : Fn) {
-    if (MBB.isEHFuncletEntry())
-      SaveBlocks.push_back(&MBB);
-    if (MBB.isReturnBlock())
-      RestoreBlocks.push_back(&MBB);
-  }
-}
-
-/// StackObjSet - A set of stack object indexes
-typedef SmallSetVector<int, 8> StackObjSet;
-
-/// runOnMachineFunction - Insert prolog/epilog code and replace abstract
-/// frame indexes with appropriate references.
-///
-bool WasmPEI::runOnMachineFunction(MachineFunction &Fn) {
-  const Function* F = Fn.getFunction();
-  const TargetRegisterInfo *TRI = Fn.getSubtarget().getRegisterInfo();
-  const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering();
-
-  // LOCALMOD: assert removed from target-independent PEI
-  //assert(!Fn.getRegInfo().getNumVirtRegs() && "Regalloc must assign all vregs");
-
-  RS = TRI->requiresRegisterScavenging(Fn) ? new RegScavenger() : nullptr;
-  FrameIndexVirtualScavenging = TRI->requiresFrameIndexScavenging(Fn);
-
-  // Calculate the MaxCallFrameSize and AdjustsStack variables for the
-  // function's frame information. Also eliminates call frame pseudo
-  // instructions.
-  calculateCallsInformation(Fn);
-
-  // Determine which of the registers in the callee save list should be saved.
-  BitVector SavedRegs;
-  TFI->determineCalleeSaves(Fn, SavedRegs, RS);
-
-  // Insert spill code for any callee saved registers that are modified.
-  assignCalleeSavedSpillSlots(Fn, SavedRegs);
-
-  // Determine placement of CSR spill/restore code:
-  // place all spills in the entry block, all restores in return blocks.
-  calculateSets(Fn);
-
-  // Add the code to save and restore the callee saved registers.
-  if (!F->hasFnAttribute(Attribute::Naked))
-    insertCSRSpillsAndRestores(Fn);
-
-  // Allow the target machine to make final modifications to the function
-  // before the frame layout is finalized.
-  TFI->processFunctionBeforeFrameFinalized(Fn, RS);
-
-  // Calculate actual frame offsets for all abstract stack objects...
-  calculateFrameObjectOffsets(Fn);
-
-  // Add prolog and epilog code to the function.  This function is required
-  // to align the stack frame as necessary for any stack variables or
-  // called functions.  Because of this, calculateCalleeSavedRegisters()
-  // must be called before this function in order to set the AdjustsStack
-  // and MaxCallFrameSize variables.
-  if (!F->hasFnAttribute(Attribute::Naked))
-    insertPrologEpilogCode(Fn);
-
-  // Replace all MO_FrameIndex operands with physical register references
-  // and actual offsets.
-  //
-  replaceFrameIndices(Fn);
-
-  // If register scavenging is needed, as we've enabled doing it as a
-  // post-pass, scavenge the virtual registers that frame index elimination
-  // inserted.
-  if (TRI->requiresRegisterScavenging(Fn) && FrameIndexVirtualScavenging) {
-    scavengeFrameVirtualRegs(Fn);
-    // Clear any vregs created by virtual scavenging.
-    // LOCALMOD: made this call conditional with scavengeFrameVirtualregs()
-    Fn.getRegInfo().clearVirtRegs();
-  }
-
-  // Warn on stack size when we exceeds the given limit.
-  MachineFrameInfo *MFI = Fn.getFrameInfo();
-  uint64_t StackSize = MFI->getStackSize();
-  if (WarnStackSize.getNumOccurrences() > 0 && WarnStackSize < StackSize) {
-    DiagnosticInfoStackSize DiagStackSize(*F, StackSize);
-    F->getContext().diagnose(DiagStackSize);
-  }
-
-  delete RS;
-  SaveBlocks.clear();
-  RestoreBlocks.clear();
-  return true;
-}
-
-/// calculateCallsInformation - Calculate the MaxCallFrameSize and AdjustsStack
-/// variables for the function's frame information and eliminate call frame
-/// pseudo instructions.
-void WasmPEI::calculateCallsInformation(MachineFunction &Fn) {
-  const TargetInstrInfo &TII = *Fn.getSubtarget().getInstrInfo();
-  const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering();
-  MachineFrameInfo *MFI = Fn.getFrameInfo();
-
-  unsigned MaxCallFrameSize = 0;
-  bool AdjustsStack = MFI->adjustsStack();
-
-  // Get the function call frame set-up and tear-down instruction opcode
-  unsigned FrameSetupOpcode = TII.getCallFrameSetupOpcode();
-  unsigned FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();
-
-  // Early exit for targets which have no call frame setup/destroy pseudo
-  // instructions.
-  if (FrameSetupOpcode == ~0u && FrameDestroyOpcode == ~0u)
-    return;
-
-  std::vector<MachineBasicBlock::iterator> FrameSDOps;
-  for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB)
-    for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ++I)
-      if (I->getOpcode() == FrameSetupOpcode ||
-          I->getOpcode() == FrameDestroyOpcode) {
-        assert(I->getNumOperands() >= 1 && "Call Frame Setup/Destroy Pseudo"
-               " instructions should have a single immediate argument!");
-        unsigned Size = I->getOperand(0).getImm();
-        if (Size > MaxCallFrameSize) MaxCallFrameSize = Size;
-        AdjustsStack = true;
-        FrameSDOps.push_back(I);
-      } else if (I->isInlineAsm()) {
-        // Some inline asm's need a stack frame, as indicated by operand 1.
-        unsigned ExtraInfo = I->getOperand(InlineAsm::MIOp_ExtraInfo).getImm();
-        if (ExtraInfo & InlineAsm::Extra_IsAlignStack)
-          AdjustsStack = true;
-      }
-
-  MFI->setAdjustsStack(AdjustsStack);
-  MFI->setMaxCallFrameSize(MaxCallFrameSize);
-
-  for (std::vector<MachineBasicBlock::iterator>::iterator
-         i = FrameSDOps.begin(), e = FrameSDOps.end(); i != e; ++i) {
-    MachineBasicBlock::iterator I = *i;
-
-    // If call frames are not being included as part of the stack frame, and
-    // the target doesn't indicate otherwise, remove the call frame pseudos
-    // here. The sub/add sp instruction pairs are still inserted, but we don't
-    // need to track the SP adjustment for frame index elimination.
-    if (TFI->canSimplifyCallFramePseudos(Fn))
-      TFI->eliminateCallFramePseudoInstr(Fn, *I->getParent(), I);
-  }
-}
-
-void WasmPEI::assignCalleeSavedSpillSlots(MachineFunction &F,
-                                      const BitVector &SavedRegs) {
-  // These are used to keep track the callee-save area. Initialize them.
-  MinCSFrameIndex = INT_MAX;
-  MaxCSFrameIndex = 0;
-
-  if (SavedRegs.empty())
-    return;
-
-  const TargetRegisterInfo *RegInfo = F.getSubtarget().getRegisterInfo();
-  const MCPhysReg *CSRegs = RegInfo->getCalleeSavedRegs(&F);
-
-  std::vector<CalleeSavedInfo> CSI;
-  for (unsigned i = 0; CSRegs[i]; ++i) {
-    unsigned Reg = CSRegs[i];
-    if (SavedRegs.test(Reg))
-      CSI.push_back(CalleeSavedInfo(Reg));
-  }
-
-  const TargetFrameLowering *TFI = F.getSubtarget().getFrameLowering();
-  MachineFrameInfo *MFI = F.getFrameInfo();
-  if (!TFI->assignCalleeSavedSpillSlots(F, RegInfo, CSI)) {
-    // If target doesn't implement this, use generic code.
-
-    if (CSI.empty())
-      return; // Early exit if no callee saved registers are modified!
-
-    unsigned NumFixedSpillSlots;
-    const TargetFrameLowering::SpillSlot *FixedSpillSlots =
-        TFI->getCalleeSavedSpillSlots(NumFixedSpillSlots);
-
-    // Now that we know which registers need to be saved and restored, allocate
-    // stack slots for them.
-    for (std::vector<CalleeSavedInfo>::iterator I = CSI.begin(), E = CSI.end();
-         I != E; ++I) {
-      unsigned Reg = I->getReg();
-      const TargetRegisterClass *RC = RegInfo->getMinimalPhysRegClass(Reg);
-
-      int FrameIdx;
-      if (RegInfo->hasReservedSpillSlot(F, Reg, FrameIdx)) {
-        I->setFrameIdx(FrameIdx);
-        continue;
-      }
-
-      // Check to see if this physreg must be spilled to a particular stack slot
-      // on this target.
-      const TargetFrameLowering::SpillSlot *FixedSlot = FixedSpillSlots;
-      while (FixedSlot != FixedSpillSlots + NumFixedSpillSlots &&
-             FixedSlot->Reg != Reg)
-        ++FixedSlot;
-
-      if (FixedSlot == FixedSpillSlots + NumFixedSpillSlots) {
-        // Nope, just spill it anywhere convenient.
-        unsigned Align = RC->getAlignment();
-        unsigned StackAlign = TFI->getStackAlignment();
-
-        // We may not be able to satisfy the desired alignment specification of
-        // the TargetRegisterClass if the stack alignment is smaller. Use the
-        // min.
-        Align = std::min(Align, StackAlign);
-        FrameIdx = MFI->CreateStackObject(RC->getSize(), Align, true);
-        if ((unsigned)FrameIdx < MinCSFrameIndex) MinCSFrameIndex = FrameIdx;
-        if ((unsigned)FrameIdx > MaxCSFrameIndex) MaxCSFrameIndex = FrameIdx;
-      } else {
-        // Spill it to the stack where we must.
-        FrameIdx =
-            MFI->CreateFixedSpillStackObject(RC->getSize(), FixedSlot->Offset);
-      }
-
-      I->setFrameIdx(FrameIdx);
-    }
-  }
-
-  MFI->setCalleeSavedInfo(CSI);
-}
-
-/// Helper function to update the liveness information for the callee-saved
-/// registers.
-static void updateLiveness(MachineFunction &MF) {
-  MachineFrameInfo *MFI = MF.getFrameInfo();
-  // Visited will contain all the basic blocks that are in the region
-  // where the callee saved registers are alive:
-  // - Anything that is not Save or Restore -> LiveThrough.
-  // - Save -> LiveIn.
-  // - Restore -> LiveOut.
-  // The live-out is not attached to the block, so no need to keep
-  // Restore in this set.
-  SmallPtrSet<MachineBasicBlock *, 8> Visited;
-  SmallVector<MachineBasicBlock *, 8> WorkList;
-  MachineBasicBlock *Entry = &MF.front();
-  MachineBasicBlock *Save = MFI->getSavePoint();
-
-  if (!Save)
-    Save = Entry;
-
-  if (Entry != Save) {
-    WorkList.push_back(Entry);
-    Visited.insert(Entry);
-  }
-  Visited.insert(Save);
-
-  MachineBasicBlock *Restore = MFI->getRestorePoint();
-  if (Restore)
-    // By construction Restore cannot be visited, otherwise it
-    // means there exists a path to Restore that does not go
-    // through Save.
-    WorkList.push_back(Restore);
-
-  while (!WorkList.empty()) {
-    const MachineBasicBlock *CurBB = WorkList.pop_back_val();
-    // By construction, the region that is after the save point is
-    // dominated by the Save and post-dominated by the Restore.
-    if (CurBB == Save && Save != Restore)
-      continue;
-    // Enqueue all the successors not already visited.
-    // Those are by construction either before Save or after Restore.
-    for (MachineBasicBlock *SuccBB : CurBB->successors())
-      if (Visited.insert(SuccBB).second)
-        WorkList.push_back(SuccBB);
-  }
-
-  const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
-
-  for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
-    for (MachineBasicBlock *MBB : Visited) {
-      MCPhysReg Reg = CSI[i].getReg();
-      // Add the callee-saved register as live-in.
-      // It's killed at the spill.
-      if (!MBB->isLiveIn(Reg))
-        MBB->addLiveIn(Reg);
-    }
-  }
-}
-
-/// insertCSRSpillsAndRestores - Insert spill and restore code for
-/// callee saved registers used in the function.
-///
-void WasmPEI::insertCSRSpillsAndRestores(MachineFunction &Fn) {
-  // Get callee saved register information.
-  MachineFrameInfo *MFI = Fn.getFrameInfo();
-  const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
-
-  MFI->setCalleeSavedInfoValid(true);
-
-  // Early exit if no callee saved registers are modified!
-  if (CSI.empty())
-    return;
-
-  const TargetInstrInfo &TII = *Fn.getSubtarget().getInstrInfo();
-  const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering();
-  const TargetRegisterInfo *TRI = Fn.getSubtarget().getRegisterInfo();
-  MachineBasicBlock::iterator I;
-
-  // Spill using target interface.
-  for (MachineBasicBlock *SaveBlock : SaveBlocks) {
-    I = SaveBlock->begin();
-    if (!TFI->spillCalleeSavedRegisters(*SaveBlock, I, CSI, TRI)) {
-      for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
-        // Insert the spill to the stack frame.
-        unsigned Reg = CSI[i].getReg();
-        const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
-        TII.storeRegToStackSlot(*SaveBlock, I, Reg, true, CSI[i].getFrameIdx(),
-                                RC, TRI);
-      }
-    }
-    // Update the live-in information of all the blocks up to the save point.
-    updateLiveness(Fn);
-  }
-
-  // Restore using target interface.
-  for (MachineBasicBlock *MBB : RestoreBlocks) {
-    I = MBB->end();
-
-    // Skip over all terminator instructions, which are part of the return
-    // sequence.
-    MachineBasicBlock::iterator I2 = I;
-    while (I2 != MBB->begin() && (--I2)->isTerminator())
-      I = I2;
-
-    bool AtStart = I == MBB->begin();
-    MachineBasicBlock::iterator BeforeI = I;
-    if (!AtStart)
-      --BeforeI;
-
-    // Restore all registers immediately before the return and any
-    // terminators that precede it.
-    if (!TFI->restoreCalleeSavedRegisters(*MBB, I, CSI, TRI)) {
-      for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
-        unsigned Reg = CSI[i].getReg();
-        const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
-        TII.loadRegFromStackSlot(*MBB, I, Reg, CSI[i].getFrameIdx(), RC, TRI);
-        assert(I != MBB->begin() &&
-               "loadRegFromStackSlot didn't insert any code!");
-        // Insert in reverse order.  loadRegFromStackSlot can insert
-        // multiple instructions.
-        if (AtStart)
-          I = MBB->begin();
-        else {
-          I = BeforeI;
-          ++I;
-        }
-      }
-    }
-  }
-}
-
-/// AdjustStackOffset - Helper function used to adjust the stack frame offset.
-static inline void
-AdjustStackOffset(MachineFrameInfo *MFI, int FrameIdx,
-                  bool StackGrowsDown, int64_t &Offset,
-                  unsigned &MaxAlign, unsigned Skew) {
-  // If the stack grows down, add the object size to find the lowest address.
-  if (StackGrowsDown)
-    Offset += MFI->getObjectSize(FrameIdx);
-
-  unsigned Align = MFI->getObjectAlignment(FrameIdx);
-
-  // If the alignment of this object is greater than that of the stack, then
-  // increase the stack alignment to match.
-  MaxAlign = std::max(MaxAlign, Align);
-
-  // Adjust to alignment boundary.
-  Offset = RoundUpToAlignment(Offset, Align, Skew);
-
-  if (StackGrowsDown) {
-    DEBUG(dbgs() << "alloc FI(" << FrameIdx << ") at SP[" << -Offset << "]\n");
-    MFI->setObjectOffset(FrameIdx, -Offset); // Set the computed offset
-  } else {
-    DEBUG(dbgs() << "alloc FI(" << FrameIdx << ") at SP[" << Offset << "]\n");
-    MFI->setObjectOffset(FrameIdx, Offset);
-    Offset += MFI->getObjectSize(FrameIdx);
-  }
-}
-
-/// AssignProtectedObjSet - Helper function to assign large stack objects (i.e.,
-/// those required to be close to the Stack Protector) to stack offsets.
-static void
-AssignProtectedObjSet(const StackObjSet &UnassignedObjs,
-                      SmallSet<int, 16> &ProtectedObjs,
-                      MachineFrameInfo *MFI, bool StackGrowsDown,
-                      int64_t &Offset, unsigned &MaxAlign, unsigned Skew) {
-
-  for (StackObjSet::const_iterator I = UnassignedObjs.begin(),
-        E = UnassignedObjs.end(); I != E; ++I) {
-    int i = *I;
-    AdjustStackOffset(MFI, i, StackGrowsDown, Offset, MaxAlign, Skew);
-    ProtectedObjs.insert(i);
-  }
-}
-
-/// calculateFrameObjectOffsets - Calculate actual frame offsets for all of the
-/// abstract stack objects.
-///
-void WasmPEI::calculateFrameObjectOffsets(MachineFunction &Fn) {
-  const TargetFrameLowering &TFI = *Fn.getSubtarget().getFrameLowering();
-  StackProtector *SP = &getAnalysis<StackProtector>();
-
-  bool StackGrowsDown =
-    TFI.getStackGrowthDirection() == TargetFrameLowering::StackGrowsDown;
-
-  // Loop over all of the stack objects, assigning sequential addresses...
-  MachineFrameInfo *MFI = Fn.getFrameInfo();
-
-  // Start at the beginning of the local area.
-  // The Offset is the distance from the stack top in the direction
-  // of stack growth -- so it's always nonnegative.
-  int LocalAreaOffset = TFI.getOffsetOfLocalArea();
-  if (StackGrowsDown)
-    LocalAreaOffset = -LocalAreaOffset;
-  assert(LocalAreaOffset >= 0
-         && "Local area offset should be in direction of stack growth");
-  int64_t Offset = LocalAreaOffset;
-
-  // Skew to be applied to alignment.
-  unsigned Skew = TFI.getStackAlignmentSkew(Fn);
-
-  // If there are fixed sized objects that are preallocated in the local area,
-  // non-fixed objects can't be allocated right at the start of local area.
-  // We currently don't support filling in holes in between fixed sized
-  // objects, so we adjust 'Offset' to point to the end of last fixed sized
-  // preallocated object.
-  for (int i = MFI->getObjectIndexBegin(); i != 0; ++i) {
-    int64_t FixedOff;
-    if (StackGrowsDown) {
-      // The maximum distance from the stack pointer is at lower address of
-      // the object -- which is given by offset. For down growing stack
-      // the offset is negative, so we negate the offset to get the distance.
-      FixedOff = -MFI->getObjectOffset(i);
-    } else {
-      // The maximum distance from the start pointer is at the upper
-      // address of the object.
-      FixedOff = MFI->getObjectOffset(i) + MFI->getObjectSize(i);
-    }
-    if (FixedOff > Offset) Offset = FixedOff;
-  }
-
-  // First assign frame offsets to stack objects that are used to spill
-  // callee saved registers.
-  if (StackGrowsDown) {
-    for (unsigned i = MinCSFrameIndex; i <= MaxCSFrameIndex; ++i) {
-      // If the stack grows down, we need to add the size to find the lowest
-      // address of the object.
-      Offset += MFI->getObjectSize(i);
-
-      unsigned Align = MFI->getObjectAlignment(i);
-      // Adjust to alignment boundary
-      Offset = RoundUpToAlignment(Offset, Align, Skew);
-
-      MFI->setObjectOffset(i, -Offset);        // Set the computed offset
-    }
-  } else {
-    int MaxCSFI = MaxCSFrameIndex, MinCSFI = MinCSFrameIndex;
-    for (int i = MaxCSFI; i >= MinCSFI ; --i) {
-      unsigned Align = MFI->getObjectAlignment(i);
-      // Adjust to alignment boundary
-      Offset = RoundUpToAlignment(Offset, Align, Skew);
-
-      MFI->setObjectOffset(i, Offset);
-      Offset += MFI->getObjectSize(i);
-    }
-  }
-
-  unsigned MaxAlign = MFI->getMaxAlignment();
-
-  // Make sure the special register scavenging spill slot is closest to the
-  // incoming stack pointer if a frame pointer is required and is closer
-  // to the incoming rather than the final stack pointer.
-  const TargetRegisterInfo *RegInfo = Fn.getSubtarget().getRegisterInfo();
-  bool EarlyScavengingSlots = (TFI.hasFP(Fn) &&
-                               TFI.isFPCloseToIncomingSP() &&
-                               RegInfo->useFPForScavengingIndex(Fn) &&
-                               !RegInfo->needsStackRealignment(Fn));
-  if (RS && EarlyScavengingSlots) {
-    SmallVector<int, 2> SFIs;
-    RS->getScavengingFrameIndices(SFIs);
-    for (SmallVectorImpl<int>::iterator I = SFIs.begin(),
-           IE = SFIs.end(); I != IE; ++I)
-      AdjustStackOffset(MFI, *I, StackGrowsDown, Offset, MaxAlign, Skew);
-  }
-
-  // FIXME: Once this is working, then enable flag will change to a target
-  // check for whether the frame is large enough to want to use virtual
-  // frame index registers. Functions which don't want/need this optimization
-  // will continue to use the existing code path.
-  if (MFI->getUseLocalStackAllocationBlock()) {
-    unsigned Align = MFI->getLocalFrameMaxAlign();
-
-    // Adjust to alignment boundary.
-    Offset = RoundUpToAlignment(Offset, Align, Skew);
-
-    DEBUG(dbgs() << "Local frame base offset: " << Offset << "\n");
-
-    // Resolve offsets for objects in the local block.
-    for (unsigned i = 0, e = MFI->getLocalFrameObjectCount(); i != e; ++i) {
-      std::pair<int, int64_t> Entry = MFI->getLocalFrameObjectMap(i);
-      int64_t FIOffset = (StackGrowsDown ? -Offset : Offset) + Entry.second;
-      DEBUG(dbgs() << "alloc FI(" << Entry.first << ") at SP[" <<
-            FIOffset << "]\n");
-      MFI->setObjectOffset(Entry.first, FIOffset);
-    }
-    // Allocate the local block
-    Offset += MFI->getLocalFrameSize();
-
-    MaxAlign = std::max(Align, MaxAlign);
-  }
-
-  // Make sure that the stack protector comes before the local variables on the
-  // stack.
-  SmallSet<int, 16> ProtectedObjs;
-  if (MFI->getStackProtectorIndex() >= 0) {
-    StackObjSet LargeArrayObjs;
-    StackObjSet SmallArrayObjs;
-    StackObjSet AddrOfObjs;
-
-    AdjustStackOffset(MFI, MFI->getStackProtectorIndex(), StackGrowsDown,
-                      Offset, MaxAlign, Skew);
-
-    // Assign large stack objects first.
-    for (unsigned i = 0, e = MFI->getObjectIndexEnd(); i != e; ++i) {
-      if (MFI->isObjectPreAllocated(i) &&
-          MFI->getUseLocalStackAllocationBlock())
-        continue;
-      if (i >= MinCSFrameIndex && i <= MaxCSFrameIndex)
-        continue;
-      if (RS && RS->isScavengingFrameIndex((int)i))
-        continue;
-      if (MFI->isDeadObjectIndex(i))
-        continue;
-      if (MFI->getStackProtectorIndex() == (int)i)
-        continue;
-
-      switch (SP->getSSPLayout(MFI->getObjectAllocation(i))) {
-      case StackProtector::SSPLK_None:
-        continue;
-      case StackProtector::SSPLK_SmallArray:
-        SmallArrayObjs.insert(i);
-        continue;
-      case StackProtector::SSPLK_AddrOf:
-        AddrOfObjs.insert(i);
-        continue;
-      case StackProtector::SSPLK_LargeArray:
-        LargeArrayObjs.insert(i);
-        continue;
-      }
-      llvm_unreachable("Unexpected SSPLayoutKind.");
-    }
-
-    AssignProtectedObjSet(LargeArrayObjs, ProtectedObjs, MFI, StackGrowsDown,
-                          Offset, MaxAlign, Skew);
-    AssignProtectedObjSet(SmallArrayObjs, ProtectedObjs, MFI, StackGrowsDown,
-                          Offset, MaxAlign, Skew);
-    AssignProtectedObjSet(AddrOfObjs, ProtectedObjs, MFI, StackGrowsDown,
-                          Offset, MaxAlign, Skew);
-  }
-
-  // Then assign frame offsets to stack objects that are not used to spill
-  // callee saved registers.
-  for (unsigned i = 0, e = MFI->getObjectIndexEnd(); i != e; ++i) {
-    if (MFI->isObjectPreAllocated(i) &&
-        MFI->getUseLocalStackAllocationBlock())
-      continue;
-    if (i >= MinCSFrameIndex && i <= MaxCSFrameIndex)
-      continue;
-    if (RS && RS->isScavengingFrameIndex((int)i))
-      continue;
-    if (MFI->isDeadObjectIndex(i))
-      continue;
-    if (MFI->getStackProtectorIndex() == (int)i)
-      continue;
-    if (ProtectedObjs.count(i))
-      continue;
-
-    AdjustStackOffset(MFI, i, StackGrowsDown, Offset, MaxAlign, Skew);
-  }
-
-  // Make sure the special register scavenging spill slot is closest to the
-  // stack pointer.
-  if (RS && !EarlyScavengingSlots) {
-    SmallVector<int, 2> SFIs;
-    RS->getScavengingFrameIndices(SFIs);
-    for (SmallVectorImpl<int>::iterator I = SFIs.begin(),
-           IE = SFIs.end(); I != IE; ++I)
-      AdjustStackOffset(MFI, *I, StackGrowsDown, Offset, MaxAlign, Skew);
-  }
-
-  if (!TFI.targetHandlesStackFrameRounding()) {
-    // If we have reserved argument space for call sites in the function
-    // immediately on entry to the current function, count it as part of the
-    // overall stack size.
-    if (MFI->adjustsStack() && TFI.hasReservedCallFrame(Fn))
-      Offset += MFI->getMaxCallFrameSize();
-
-    // Round up the size to a multiple of the alignment.  If the function has
-    // any calls or alloca's, align to the target's StackAlignment value to
-    // ensure that the callee's frame or the alloca data is suitably aligned;
-    // otherwise, for leaf functions, align to the TransientStackAlignment
-    // value.
-    unsigned StackAlign;
-    if (MFI->adjustsStack() || MFI->hasVarSizedObjects() ||
-        (RegInfo->needsStackRealignment(Fn) && MFI->getObjectIndexEnd() != 0))
-      StackAlign = TFI.getStackAlignment();
-    else
-      StackAlign = TFI.getTransientStackAlignment();
-
-    // If the frame pointer is eliminated, all frame offsets will be relative to
-    // SP not FP. Align to MaxAlign so this works.
-    StackAlign = std::max(StackAlign, MaxAlign);
-    Offset = RoundUpToAlignment(Offset, StackAlign, Skew);
-  }
-
-  // Update frame info to pretend that this is part of the stack...
-  int64_t StackSize = Offset - LocalAreaOffset;
-  MFI->setStackSize(StackSize);
-  NumBytesStackSpace += StackSize;
-}
-
-/// insertPrologEpilogCode - Scan the function for modified callee saved
-/// registers, insert spill code for these callee saved registers, then add
-/// prolog and epilog code to the function.
-///
-void WasmPEI::insertPrologEpilogCode(MachineFunction &Fn) {
-  const TargetFrameLowering &TFI = *Fn.getSubtarget().getFrameLowering();
-
-  // Add prologue to the function...
-  for (MachineBasicBlock *SaveBlock : SaveBlocks)
-    TFI.emitPrologue(Fn, *SaveBlock);
-
-  // Add epilogue to restore the callee-save registers in each exiting block.
-  for (MachineBasicBlock *RestoreBlock : RestoreBlocks)
-    TFI.emitEpilogue(Fn, *RestoreBlock);
-
-  for (MachineBasicBlock *SaveBlock : SaveBlocks)
-    TFI.inlineStackProbe(Fn, *SaveBlock);
-
-  // Emit additional code that is required to support segmented stacks, if
-  // we've been asked for it.  This, when linked with a runtime with support
-  // for segmented stacks (libgcc is one), will result in allocating stack
-  // space in small chunks instead of one large contiguous block.
-  if (Fn.shouldSplitStack()) {
-    for (MachineBasicBlock *SaveBlock : SaveBlocks)
-      TFI.adjustForSegmentedStacks(Fn, *SaveBlock);
-  }
-
-  // Emit additional code that is required to explicitly handle the stack in
-  // HiPE native code (if needed) when loaded in the Erlang/OTP runtime. The
-  // approach is rather similar to that of Segmented Stacks, but it uses a
-  // different conditional check and another BIF for allocating more stack
-  // space.
-  if (Fn.getFunction()->getCallingConv() == CallingConv::HiPE)
-    for (MachineBasicBlock *SaveBlock : SaveBlocks)
-      TFI.adjustForHiPEPrologue(Fn, *SaveBlock);
-}
-
-/// replaceFrameIndices - Replace all MO_FrameIndex operands with physical
-/// register references and actual offsets.
-///
-void WasmPEI::replaceFrameIndices(MachineFunction &Fn) {
-  const TargetFrameLowering &TFI = *Fn.getSubtarget().getFrameLowering();
-  if (!TFI.needsFrameIndexResolution(Fn)) return;
-
-  // Store SPAdj at exit of a basic block.
-  SmallVector<int, 8> SPState;
-  SPState.resize(Fn.getNumBlockIDs());
-  SmallPtrSet<MachineBasicBlock*, 8> Reachable;
-
-  // Iterate over the reachable blocks in DFS order.
-  for (auto DFI = df_ext_begin(&Fn, Reachable), DFE = df_ext_end(&Fn, Reachable);
-       DFI != DFE; ++DFI) {
-    int SPAdj = 0;
-    // Check the exit state of the DFS stack predecessor.
-    if (DFI.getPathLength() >= 2) {
-      MachineBasicBlock *StackPred = DFI.getPath(DFI.getPathLength() - 2);
-      assert(Reachable.count(StackPred) &&
-             "DFS stack predecessor is already visited.\n");
-      SPAdj = SPState[StackPred->getNumber()];
-    }
-    MachineBasicBlock *BB = *DFI;
-    replaceFrameIndices(BB, Fn, SPAdj);
-    SPState[BB->getNumber()] = SPAdj;
-  }
-
-  // Handle the unreachable blocks.
-  for (auto &BB : Fn) {
-    if (Reachable.count(&BB))
-      // Already handled in DFS traversal.
-      continue;
-    int SPAdj = 0;
-    replaceFrameIndices(&BB, Fn, SPAdj);
-  }
-}
-
-void WasmPEI::replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &Fn,
-                              int &SPAdj) {
-  assert(Fn.getSubtarget().getRegisterInfo() &&
-         "getRegisterInfo() must be implemented!");
-  const TargetInstrInfo &TII = *Fn.getSubtarget().getInstrInfo();
-  const TargetRegisterInfo &TRI = *Fn.getSubtarget().getRegisterInfo();
-  const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering();
-  unsigned FrameSetupOpcode = TII.getCallFrameSetupOpcode();
-  unsigned FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();
-
-  if (RS && !FrameIndexVirtualScavenging) RS->enterBasicBlock(BB);
-
-  bool InsideCallSequence = false;
-
-  for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
-
-    if (I->getOpcode() == FrameSetupOpcode ||
-        I->getOpcode() == FrameDestroyOpcode) {
-      InsideCallSequence = (I->getOpcode() == FrameSetupOpcode);
-      SPAdj += TII.getSPAdjust(I);
-
-      MachineBasicBlock::iterator PrevI = BB->end();
-      if (I != BB->begin()) PrevI = std::prev(I);
-      TFI->eliminateCallFramePseudoInstr(Fn, *BB, I);
-
-      // Visit the instructions created by eliminateCallFramePseudoInstr().
-      if (PrevI == BB->end())
-        I = BB->begin();     // The replaced instr was the first in the block.
-      else
-        I = std::next(PrevI);
-      continue;
-    }
-
-    MachineInstr *MI = I;
-    bool DoIncr = true;
-    for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
-      if (!MI->getOperand(i).isFI())
-        continue;
-
-      // Frame indices in debug values are encoded in a target independent
-      // way with simply the frame index and offset rather than any
-      // target-specific addressing mode.
-      if (MI->isDebugValue()) {
-        assert(i == 0 && "Frame indices can only appear as the first "
-                         "operand of a DBG_VALUE machine instruction");
-        unsigned Reg;
-        MachineOperand &Offset = MI->getOperand(1);
-        Offset.setImm(Offset.getImm() +
-                      TFI->getFrameIndexReference(
-                          Fn, MI->getOperand(0).getIndex(), Reg));
-        MI->getOperand(0).ChangeToRegister(Reg, false /*isDef*/);
-        continue;
-      }
-
-      // TODO: This code should be commoned with the code for
-      // PATCHPOINT. There's no good reason for the difference in
-      // implementation other than historical accident.  The only
-      // remaining difference is the unconditional use of the stack
-      // pointer as the base register.
-      if (MI->getOpcode() == TargetOpcode::STATEPOINT) {
-        assert((!MI->isDebugValue() || i == 0) &&
-               "Frame indicies can only appear as the first operand of a "
-               "DBG_VALUE machine instruction");
-        unsigned Reg;
-        MachineOperand &Offset = MI->getOperand(i + 1);
-        const unsigned refOffset =
-          TFI->getFrameIndexReferenceFromSP(Fn, MI->getOperand(i).getIndex(),
-                                            Reg);
-
-        Offset.setImm(Offset.getImm() + refOffset);
-        MI->getOperand(i).ChangeToRegister(Reg, false /*isDef*/);
-        continue;
-      }
-
-      // Some instructions (e.g. inline asm instructions) can have
-      // multiple frame indices and/or cause eliminateFrameIndex
-      // to insert more than one instruction. We need the register
-      // scavenger to go through all of these instructions so that
-      // it can update its register information. We keep the
-      // iterator at the point before insertion so that we can
-      // revisit them in full.
-      bool AtBeginning = (I == BB->begin());
-      if (!AtBeginning) --I;
-
-      // If this instruction has a FrameIndex operand, we need to
-      // use that target machine register info object to eliminate
-      // it.
-      TRI.eliminateFrameIndex(MI, SPAdj, i,
-                              FrameIndexVirtualScavenging ?  nullptr : RS);
-
-      // Reset the iterator if we were at the beginning of the BB.
-      if (AtBeginning) {
-        I = BB->begin();
-        DoIncr = false;
-      }
-
-      MI = nullptr;
-      break;
-    }
-
-    // If we are looking at a call sequence, we need to keep track of
-    // the SP adjustment made by each instruction in the sequence.
-    // This includes both the frame setup/destroy pseudos (handled above),
-    // as well as other instructions that have side effects w.r.t the SP.
-    // Note that this must come after eliminateFrameIndex, because 
-    // if I itself referred to a frame index, we shouldn't count its own
-    // adjustment.
-    if (MI && InsideCallSequence)
-      SPAdj += TII.getSPAdjust(MI);
-
-    if (DoIncr && I != BB->end()) ++I;
-
-    // Update register states.
-    if (RS && !FrameIndexVirtualScavenging && MI) RS->forward(MI);
-  }
-}
-
-/// scavengeFrameVirtualRegs - Replace all frame index virtual registers
-/// with physical registers. Use the register scavenger to find an
-/// appropriate register to use.
-///
-/// FIXME: Iterating over the instruction stream is unnecessary. We can simply
-/// iterate over the vreg use list, which at this point only contains machine
-/// operands for which eliminateFrameIndex need a new scratch reg.
-void
-WasmPEI::scavengeFrameVirtualRegs(MachineFunction &Fn) {
-  // Run through the instructions and find any virtual registers.
-  for (MachineFunction::iterator BB = Fn.begin(),
-       E = Fn.end(); BB != E; ++BB) {
-    RS->enterBasicBlock(&*BB);
-
-    int SPAdj = 0;
-
-    // The instruction stream may change in the loop, so check BB->end()
-    // directly.
-    for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
-      // We might end up here again with a NULL iterator if we scavenged a
-      // register for which we inserted spill code for definition by what was
-      // originally the first instruction in BB.
-      if (I == MachineBasicBlock::iterator(nullptr))
-        I = BB->begin();
-
-      MachineInstr *MI = I;
-      MachineBasicBlock::iterator J = std::next(I);
-      MachineBasicBlock::iterator P =
-                         I == BB->begin() ? MachineBasicBlock::iterator(nullptr)
-                                          : std::prev(I);
-
-      // RS should process this instruction before we might scavenge at this
-      // location. This is because we might be replacing a virtual register
-      // defined by this instruction, and if so, registers killed by this
-      // instruction are available, and defined registers are not.
-      RS->forward(I);
-
-      for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
-        if (MI->getOperand(i).isReg()) {
-          MachineOperand &MO = MI->getOperand(i);
-          unsigned Reg = MO.getReg();
-          if (Reg == 0)
-            continue;
-          if (!TargetRegisterInfo::isVirtualRegister(Reg))
-            continue;
-
-          // When we first encounter a new virtual register, it
-          // must be a definition.
-          assert(MI->getOperand(i).isDef() &&
-                 "frame index virtual missing def!");
-          // Scavenge a new scratch register
-          const TargetRegisterClass *RC = Fn.getRegInfo().getRegClass(Reg);
-          unsigned ScratchReg = RS->scavengeRegister(RC, J, SPAdj);
-
-          ++NumScavengedRegs;
-
-          // Replace this reference to the virtual register with the
-          // scratch register.
-          assert (ScratchReg && "Missing scratch register!");
-          Fn.getRegInfo().replaceRegWith(Reg, ScratchReg);
-          
-          // Because this instruction was processed by the RS before this
-          // register was allocated, make sure that the RS now records the
-          // register as being used.
-          RS->setRegUsed(ScratchReg);
-        }
-      }
-
-      // If the scavenger needed to use one of its spill slots, the
-      // spill code will have been inserted in between I and J. This is a
-      // problem because we need the spill code before I: Move I to just
-      // prior to J.
-      if (I != std::prev(J)) {
-        BB->splice(J, &*BB, I);
-
-        // Before we move I, we need to prepare the RS to visit I again.
-        // Specifically, RS will assert if it sees uses of registers that
-        // it believes are undefined. Because we have already processed
-        // register kills in I, when it visits I again, it will believe that
-        // those registers are undefined. To avoid this situation, unprocess
-        // the instruction I.
-        assert(RS->getCurrentPosition() == I &&
-          "The register scavenger has an unexpected position");
-        I = P;
-        RS->unprocess(P);
-      } else
-        ++I;
-    }
-  }
-}