diff --git a/llvm/lib/CodeGen/CMakeLists.txt b/llvm/lib/CodeGen/CMakeLists.txt
index 48bf3545e733..f0b2dfe365b7 100644
--- a/llvm/lib/CodeGen/CMakeLists.txt
+++ b/llvm/lib/CodeGen/CMakeLists.txt
@@ -22,6 +22,7 @@ add_llvm_library(LLVMCodeGen
   ForwardControlFlowIntegrity.cpp
   GCMetadata.cpp
   GCMetadataPrinter.cpp
+  GCRootLowering.cpp
   GCStrategy.cpp
   GlobalMerge.cpp
   IfConversion.cpp
diff --git a/llvm/lib/CodeGen/GCRootLowering.cpp b/llvm/lib/CodeGen/GCRootLowering.cpp
new file mode 100644
index 000000000000..4b788d3ffce1
--- /dev/null
+++ b/llvm/lib/CodeGen/GCRootLowering.cpp
@@ -0,0 +1,388 @@
+//===-- GCRootLowering.cpp - Garbage collection infrastructure ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the lowering for the gc.root mechanism.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/GCStrategy.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.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"
+
+using namespace llvm;
+
+namespace {
+
+  /// LowerIntrinsics - This pass rewrites calls to the llvm.gcread or
+  /// llvm.gcwrite intrinsics, replacing them with simple loads and stores as
+  /// directed by the GCStrategy. It also performs automatic root initialization
+  /// and custom intrinsic lowering.
+  class LowerIntrinsics : public FunctionPass {
+    static bool NeedsDefaultLoweringPass(const GCStrategy &C);
+    static bool NeedsCustomLoweringPass(const GCStrategy &C);
+    static bool CouldBecomeSafePoint(Instruction *I);
+    bool PerformDefaultLowering(Function &F, GCStrategy &Coll);
+    static bool InsertRootInitializers(Function &F,
+                                       AllocaInst **Roots, unsigned Count);
+
+  public:
+    static char ID;
+
+    LowerIntrinsics();
+    const char *getPassName() const override;
+    void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+    bool doInitialization(Module &M) override;
+    bool runOnFunction(Function &F) override;
+  };
+
+
+  /// GCMachineCodeAnalysis - This is a target-independent pass over the machine
+  /// function representation to identify safe points for the garbage collector
+  /// in the machine code. It inserts labels at safe points and populates a
+  /// GCMetadata record for each function.
+  class GCMachineCodeAnalysis : public MachineFunctionPass {
+    const TargetMachine *TM;
+    GCFunctionInfo *FI;
+    MachineModuleInfo *MMI;
+    const TargetInstrInfo *TII;
+
+    void FindSafePoints(MachineFunction &MF);
+    void VisitCallPoint(MachineBasicBlock::iterator MI);
+    MCSymbol *InsertLabel(MachineBasicBlock &MBB,
+                          MachineBasicBlock::iterator MI,
+                          DebugLoc DL) const;
+
+    void FindStackOffsets(MachineFunction &MF);
+
+  public:
+    static char ID;
+
+    GCMachineCodeAnalysis();
+    void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+    bool runOnMachineFunction(MachineFunction &MF) override;
+  };
+
+}
+
+// -----------------------------------------------------------------------------
+
+INITIALIZE_PASS_BEGIN(LowerIntrinsics, "gc-lowering", "GC Lowering",
+                      false, false)
+INITIALIZE_PASS_DEPENDENCY(GCModuleInfo)
+INITIALIZE_PASS_END(LowerIntrinsics, "gc-lowering", "GC Lowering", false, false)
+
+FunctionPass *llvm::createGCLoweringPass() {
+  return new LowerIntrinsics();
+}
+
+char LowerIntrinsics::ID = 0;
+
+LowerIntrinsics::LowerIntrinsics()
+  : FunctionPass(ID) {
+    initializeLowerIntrinsicsPass(*PassRegistry::getPassRegistry());
+  }
+
+const char *LowerIntrinsics::getPassName() const {
+  return "Lower Garbage Collection Instructions";
+}
+
+void LowerIntrinsics::getAnalysisUsage(AnalysisUsage &AU) const {
+  FunctionPass::getAnalysisUsage(AU);
+  AU.addRequired<GCModuleInfo>();
+  AU.addPreserved<DominatorTreeWrapperPass>();
+}
+
+/// doInitialization - If this module uses the GC intrinsics, find them now.
+bool LowerIntrinsics::doInitialization(Module &M) {
+  // FIXME: This is rather antisocial in the context of a JIT since it performs
+  //        work against the entire module. But this cannot be done at
+  //        runFunction time (initializeCustomLowering likely needs to change
+  //        the module).
+  GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
+  assert(MI && "LowerIntrinsics didn't require GCModuleInfo!?");
+  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
+    if (!I->isDeclaration() && I->hasGC())
+      MI->getFunctionInfo(*I); // Instantiate the GC strategy.
+
+  bool MadeChange = false;
+  for (GCModuleInfo::iterator I = MI->begin(), E = MI->end(); I != E; ++I)
+    if (NeedsCustomLoweringPass(**I))
+      if ((*I)->initializeCustomLowering(M))
+        MadeChange = true;
+
+  return MadeChange;
+}
+
+bool LowerIntrinsics::InsertRootInitializers(Function &F, AllocaInst **Roots,
+                                                          unsigned Count) {
+  // Scroll past alloca instructions.
+  BasicBlock::iterator IP = F.getEntryBlock().begin();
+  while (isa<AllocaInst>(IP)) ++IP;
+
+  // Search for initializers in the initial BB.
+  SmallPtrSet<AllocaInst*,16> InitedRoots;
+  for (; !CouldBecomeSafePoint(IP); ++IP)
+    if (StoreInst *SI = dyn_cast<StoreInst>(IP))
+      if (AllocaInst *AI =
+          dyn_cast<AllocaInst>(SI->getOperand(1)->stripPointerCasts()))
+        InitedRoots.insert(AI);
+
+  // Add root initializers.
+  bool MadeChange = false;
+
+  for (AllocaInst **I = Roots, **E = Roots + Count; I != E; ++I)
+    if (!InitedRoots.count(*I)) {
+      StoreInst* SI = new StoreInst(ConstantPointerNull::get(cast<PointerType>(
+                        cast<PointerType>((*I)->getType())->getElementType())),
+                        *I);
+      SI->insertAfter(*I);
+      MadeChange = true;
+    }
+
+  return MadeChange;
+}
+
+bool LowerIntrinsics::NeedsDefaultLoweringPass(const GCStrategy &C) {
+  // Default lowering is necessary only if read or write barriers have a default
+  // action. The default for roots is no action.
+  return !C.customWriteBarrier()
+      || !C.customReadBarrier()
+      || C.initializeRoots();
+}
+
+bool LowerIntrinsics::NeedsCustomLoweringPass(const GCStrategy &C) {
+  // Custom lowering is only necessary if enabled for some action.
+  return C.customWriteBarrier()
+      || C.customReadBarrier()
+      || C.customRoots();
+}
+
+/// CouldBecomeSafePoint - Predicate to conservatively determine whether the
+/// instruction could introduce a safe point.
+bool LowerIntrinsics::CouldBecomeSafePoint(Instruction *I) {
+  // The natural definition of instructions which could introduce safe points
+  // are:
+  //
+  //   - call, invoke (AfterCall, BeforeCall)
+  //   - phis (Loops)
+  //   - invoke, ret, unwind (Exit)
+  //
+  // However, instructions as seemingly inoccuous as arithmetic can become
+  // libcalls upon lowering (e.g., div i64 on a 32-bit platform), so instead
+  // it is necessary to take a conservative approach.
+
+  if (isa<AllocaInst>(I) || isa<GetElementPtrInst>(I) ||
+      isa<StoreInst>(I) || isa<LoadInst>(I))
+    return false;
+
+  // llvm.gcroot is safe because it doesn't do anything at runtime.
+  if (CallInst *CI = dyn_cast<CallInst>(I))
+    if (Function *F = CI->getCalledFunction())
+      if (unsigned IID = F->getIntrinsicID())
+        if (IID == Intrinsic::gcroot)
+          return false;
+
+  return true;
+}
+
+/// runOnFunction - Replace gcread/gcwrite intrinsics with loads and stores.
+/// Leave gcroot intrinsics; the code generator needs to see those.
+bool LowerIntrinsics::runOnFunction(Function &F) {
+  // Quick exit for functions that do not use GC.
+  if (!F.hasGC())
+    return false;
+
+  GCFunctionInfo &FI = getAnalysis<GCModuleInfo>().getFunctionInfo(F);
+  GCStrategy &S = FI.getStrategy();
+
+  bool MadeChange = false;
+
+  if (NeedsDefaultLoweringPass(S))
+    MadeChange |= PerformDefaultLowering(F, S);
+
+  bool UseCustomLoweringPass = NeedsCustomLoweringPass(S);
+  if (UseCustomLoweringPass)
+    MadeChange |= S.performCustomLowering(F);
+
+  // Custom lowering may modify the CFG, so dominators must be recomputed.
+  if (UseCustomLoweringPass) {
+    if (DominatorTreeWrapperPass *DTWP =
+            getAnalysisIfAvailable<DominatorTreeWrapperPass>())
+      DTWP->getDomTree().recalculate(F);
+  }
+
+  return MadeChange;
+}
+
+bool LowerIntrinsics::PerformDefaultLowering(Function &F, GCStrategy &S) {
+  bool LowerWr = !S.customWriteBarrier();
+  bool LowerRd = !S.customReadBarrier();
+  bool InitRoots = S.initializeRoots();
+
+  SmallVector<AllocaInst*, 32> Roots;
+
+  bool MadeChange = false;
+  for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
+    for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E;) {
+      if (IntrinsicInst *CI = dyn_cast<IntrinsicInst>(II++)) {
+        Function *F = CI->getCalledFunction();
+        switch (F->getIntrinsicID()) {
+        case Intrinsic::gcwrite:
+          if (LowerWr) {
+            // Replace a write barrier with a simple store.
+            Value *St = new StoreInst(CI->getArgOperand(0),
+                                      CI->getArgOperand(2), CI);
+            CI->replaceAllUsesWith(St);
+            CI->eraseFromParent();
+          }
+          break;
+        case Intrinsic::gcread:
+          if (LowerRd) {
+            // Replace a read barrier with a simple load.
+            Value *Ld = new LoadInst(CI->getArgOperand(1), "", CI);
+            Ld->takeName(CI);
+            CI->replaceAllUsesWith(Ld);
+            CI->eraseFromParent();
+          }
+          break;
+        case Intrinsic::gcroot:
+          if (InitRoots) {
+            // Initialize the GC root, but do not delete the intrinsic. The
+            // backend needs the intrinsic to flag the stack slot.
+            Roots.push_back(cast<AllocaInst>(
+                              CI->getArgOperand(0)->stripPointerCasts()));
+          }
+          break;
+        default:
+          continue;
+        }
+
+        MadeChange = true;
+      }
+    }
+  }
+
+  if (Roots.size())
+    MadeChange |= InsertRootInitializers(F, Roots.begin(), Roots.size());
+
+  return MadeChange;
+}
+
+// -----------------------------------------------------------------------------
+
+char GCMachineCodeAnalysis::ID = 0;
+char &llvm::GCMachineCodeAnalysisID = GCMachineCodeAnalysis::ID;
+
+INITIALIZE_PASS(GCMachineCodeAnalysis, "gc-analysis",
+                "Analyze Machine Code For Garbage Collection", false, false)
+
+GCMachineCodeAnalysis::GCMachineCodeAnalysis()
+  : MachineFunctionPass(ID) {}
+
+void GCMachineCodeAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
+  MachineFunctionPass::getAnalysisUsage(AU);
+  AU.setPreservesAll();
+  AU.addRequired<MachineModuleInfo>();
+  AU.addRequired<GCModuleInfo>();
+}
+
+MCSymbol *GCMachineCodeAnalysis::InsertLabel(MachineBasicBlock &MBB,
+                                             MachineBasicBlock::iterator MI,
+                                             DebugLoc DL) const {
+  MCSymbol *Label = MBB.getParent()->getContext().CreateTempSymbol();
+  BuildMI(MBB, MI, DL, TII->get(TargetOpcode::GC_LABEL)).addSym(Label);
+  return Label;
+}
+
+void GCMachineCodeAnalysis::VisitCallPoint(MachineBasicBlock::iterator CI) {
+  // Find the return address (next instruction), too, so as to bracket the call
+  // instruction.
+  MachineBasicBlock::iterator RAI = CI;
+  ++RAI;
+
+  if (FI->getStrategy().needsSafePoint(GC::PreCall)) {
+    MCSymbol* Label = InsertLabel(*CI->getParent(), CI, CI->getDebugLoc());
+    FI->addSafePoint(GC::PreCall, Label, CI->getDebugLoc());
+  }
+
+  if (FI->getStrategy().needsSafePoint(GC::PostCall)) {
+    MCSymbol* Label = InsertLabel(*CI->getParent(), RAI, CI->getDebugLoc());
+    FI->addSafePoint(GC::PostCall, Label, CI->getDebugLoc());
+  }
+}
+
+void GCMachineCodeAnalysis::FindSafePoints(MachineFunction &MF) {
+  for (MachineFunction::iterator BBI = MF.begin(),
+                                 BBE = MF.end(); BBI != BBE; ++BBI)
+    for (MachineBasicBlock::iterator MI = BBI->begin(),
+                                     ME = BBI->end(); MI != ME; ++MI)
+      if (MI->isCall())
+        VisitCallPoint(MI);
+}
+
+void GCMachineCodeAnalysis::FindStackOffsets(MachineFunction &MF) {
+  const TargetFrameLowering *TFI = TM->getSubtargetImpl()->getFrameLowering();
+  assert(TFI && "TargetRegisterInfo not available!");
+
+  for (GCFunctionInfo::roots_iterator RI = FI->roots_begin();
+       RI != FI->roots_end();) {
+    // If the root references a dead object, no need to keep it.
+    if (MF.getFrameInfo()->isDeadObjectIndex(RI->Num)) {
+      RI = FI->removeStackRoot(RI);
+    } else {
+      RI->StackOffset = TFI->getFrameIndexOffset(MF, RI->Num);
+      ++RI;
+    }
+  }
+}
+
+bool GCMachineCodeAnalysis::runOnMachineFunction(MachineFunction &MF) {
+  // Quick exit for functions that do not use GC.
+  if (!MF.getFunction()->hasGC())
+    return false;
+
+  FI = &getAnalysis<GCModuleInfo>().getFunctionInfo(*MF.getFunction());
+  if (!FI->getStrategy().needsSafePoints())
+    return false;
+
+  TM = &MF.getTarget();
+  MMI = &getAnalysis<MachineModuleInfo>();
+  TII = TM->getSubtargetImpl()->getInstrInfo();
+
+  // Find the size of the stack frame.
+  FI->setFrameSize(MF.getFrameInfo()->getStackSize());
+
+  // Find all safe points.
+  if (FI->getStrategy().customSafePoints()) {
+    FI->getStrategy().findCustomSafePoints(*FI, MF);
+  } else {
+    FindSafePoints(MF);
+  }
+
+  // Find the stack offsets for all roots.
+  FindStackOffsets(MF);
+
+  return false;
+}
diff --git a/llvm/lib/CodeGen/GCStrategy.cpp b/llvm/lib/CodeGen/GCStrategy.cpp
index 05c36fcb00d4..982402b8ce3e 100644
--- a/llvm/lib/CodeGen/GCStrategy.cpp
+++ b/llvm/lib/CodeGen/GCStrategy.cpp
@@ -1,4 +1,4 @@
-//===-- GCStrategy.cpp - Garbage collection infrastructure -----------------===//
+//===-- GCStrategy.cpp - Garbage Collector Description --------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -7,91 +7,15 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This file implements target- and collector-independent garbage collection
-// infrastructure.
-//
-// GCMachineCodeAnalysis identifies the GC safe points in the machine code.
-// Roots are identified in SelectionDAGISel.
+// This file implements the policy object GCStrategy which describes the
+// behavior of a given garbage collector.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/CodeGen/GCStrategy.h"
-#include "llvm/CodeGen/MachineFrameInfo.h"
-#include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineInstrBuilder.h"
-#include "llvm/CodeGen/MachineModuleInfo.h"
-#include "llvm/CodeGen/Passes.h"
-#include "llvm/IR/Dominators.h"
-#include "llvm/IR/IntrinsicInst.h"
-#include "llvm/IR/Module.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/ErrorHandling.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"
 
 using namespace llvm;
 
-namespace {
-
-  /// LowerIntrinsics - This pass rewrites calls to the llvm.gcread or
-  /// llvm.gcwrite intrinsics, replacing them with simple loads and stores as
-  /// directed by the GCStrategy. It also performs automatic root initialization
-  /// and custom intrinsic lowering.
-  class LowerIntrinsics : public FunctionPass {
-    static bool NeedsDefaultLoweringPass(const GCStrategy &C);
-    static bool NeedsCustomLoweringPass(const GCStrategy &C);
-    static bool CouldBecomeSafePoint(Instruction *I);
-    bool PerformDefaultLowering(Function &F, GCStrategy &Coll);
-    static bool InsertRootInitializers(Function &F,
-                                       AllocaInst **Roots, unsigned Count);
-
-  public:
-    static char ID;
-
-    LowerIntrinsics();
-    const char *getPassName() const override;
-    void getAnalysisUsage(AnalysisUsage &AU) const override;
-
-    bool doInitialization(Module &M) override;
-    bool runOnFunction(Function &F) override;
-  };
-
-
-  /// GCMachineCodeAnalysis - This is a target-independent pass over the machine
-  /// function representation to identify safe points for the garbage collector
-  /// in the machine code. It inserts labels at safe points and populates a
-  /// GCMetadata record for each function.
-  class GCMachineCodeAnalysis : public MachineFunctionPass {
-    const TargetMachine *TM;
-    GCFunctionInfo *FI;
-    MachineModuleInfo *MMI;
-    const TargetInstrInfo *TII;
-
-    void FindSafePoints(MachineFunction &MF);
-    void VisitCallPoint(MachineBasicBlock::iterator MI);
-    MCSymbol *InsertLabel(MachineBasicBlock &MBB,
-                          MachineBasicBlock::iterator MI,
-                          DebugLoc DL) const;
-
-    void FindStackOffsets(MachineFunction &MF);
-
-  public:
-    static char ID;
-
-    GCMachineCodeAnalysis();
-    void getAnalysisUsage(AnalysisUsage &AU) const override;
-
-    bool runOnMachineFunction(MachineFunction &MF) override;
-  };
-
-}
-
-// -----------------------------------------------------------------------------
-
 GCStrategy::GCStrategy() :
   UseStatepoints(false),
   NeededSafePoints(0),
@@ -102,304 +26,3 @@ GCStrategy::GCStrategy() :
   InitRoots(true),
   UsesMetadata(false)
 {}
-
-// -----------------------------------------------------------------------------
-
-INITIALIZE_PASS_BEGIN(LowerIntrinsics, "gc-lowering", "GC Lowering",
-                      false, false)
-INITIALIZE_PASS_DEPENDENCY(GCModuleInfo)
-INITIALIZE_PASS_END(LowerIntrinsics, "gc-lowering", "GC Lowering", false, false)
-
-FunctionPass *llvm::createGCLoweringPass() {
-  return new LowerIntrinsics();
-}
-
-char LowerIntrinsics::ID = 0;
-
-LowerIntrinsics::LowerIntrinsics()
-  : FunctionPass(ID) {
-    initializeLowerIntrinsicsPass(*PassRegistry::getPassRegistry());
-  }
-
-const char *LowerIntrinsics::getPassName() const {
-  return "Lower Garbage Collection Instructions";
-}
-
-void LowerIntrinsics::getAnalysisUsage(AnalysisUsage &AU) const {
-  FunctionPass::getAnalysisUsage(AU);
-  AU.addRequired<GCModuleInfo>();
-  AU.addPreserved<DominatorTreeWrapperPass>();
-}
-
-/// doInitialization - If this module uses the GC intrinsics, find them now.
-bool LowerIntrinsics::doInitialization(Module &M) {
-  // FIXME: This is rather antisocial in the context of a JIT since it performs
-  //        work against the entire module. But this cannot be done at
-  //        runFunction time (initializeCustomLowering likely needs to change
-  //        the module).
-  GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
-  assert(MI && "LowerIntrinsics didn't require GCModuleInfo!?");
-  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
-    if (!I->isDeclaration() && I->hasGC())
-      MI->getFunctionInfo(*I); // Instantiate the GC strategy.
-
-  bool MadeChange = false;
-  for (GCModuleInfo::iterator I = MI->begin(), E = MI->end(); I != E; ++I)
-    if (NeedsCustomLoweringPass(**I))
-      if ((*I)->initializeCustomLowering(M))
-        MadeChange = true;
-
-  return MadeChange;
-}
-
-bool LowerIntrinsics::InsertRootInitializers(Function &F, AllocaInst **Roots,
-                                                          unsigned Count) {
-  // Scroll past alloca instructions.
-  BasicBlock::iterator IP = F.getEntryBlock().begin();
-  while (isa<AllocaInst>(IP)) ++IP;
-
-  // Search for initializers in the initial BB.
-  SmallPtrSet<AllocaInst*,16> InitedRoots;
-  for (; !CouldBecomeSafePoint(IP); ++IP)
-    if (StoreInst *SI = dyn_cast<StoreInst>(IP))
-      if (AllocaInst *AI =
-          dyn_cast<AllocaInst>(SI->getOperand(1)->stripPointerCasts()))
-        InitedRoots.insert(AI);
-
-  // Add root initializers.
-  bool MadeChange = false;
-
-  for (AllocaInst **I = Roots, **E = Roots + Count; I != E; ++I)
-    if (!InitedRoots.count(*I)) {
-      StoreInst* SI = new StoreInst(ConstantPointerNull::get(cast<PointerType>(
-                        cast<PointerType>((*I)->getType())->getElementType())),
-                        *I);
-      SI->insertAfter(*I);
-      MadeChange = true;
-    }
-
-  return MadeChange;
-}
-
-bool LowerIntrinsics::NeedsDefaultLoweringPass(const GCStrategy &C) {
-  // Default lowering is necessary only if read or write barriers have a default
-  // action. The default for roots is no action.
-  return !C.customWriteBarrier()
-      || !C.customReadBarrier()
-      || C.initializeRoots();
-}
-
-bool LowerIntrinsics::NeedsCustomLoweringPass(const GCStrategy &C) {
-  // Custom lowering is only necessary if enabled for some action.
-  return C.customWriteBarrier()
-      || C.customReadBarrier()
-      || C.customRoots();
-}
-
-/// CouldBecomeSafePoint - Predicate to conservatively determine whether the
-/// instruction could introduce a safe point.
-bool LowerIntrinsics::CouldBecomeSafePoint(Instruction *I) {
-  // The natural definition of instructions which could introduce safe points
-  // are:
-  //
-  //   - call, invoke (AfterCall, BeforeCall)
-  //   - phis (Loops)
-  //   - invoke, ret, unwind (Exit)
-  //
-  // However, instructions as seemingly inoccuous as arithmetic can become
-  // libcalls upon lowering (e.g., div i64 on a 32-bit platform), so instead
-  // it is necessary to take a conservative approach.
-
-  if (isa<AllocaInst>(I) || isa<GetElementPtrInst>(I) ||
-      isa<StoreInst>(I) || isa<LoadInst>(I))
-    return false;
-
-  // llvm.gcroot is safe because it doesn't do anything at runtime.
-  if (CallInst *CI = dyn_cast<CallInst>(I))
-    if (Function *F = CI->getCalledFunction())
-      if (unsigned IID = F->getIntrinsicID())
-        if (IID == Intrinsic::gcroot)
-          return false;
-
-  return true;
-}
-
-/// runOnFunction - Replace gcread/gcwrite intrinsics with loads and stores.
-/// Leave gcroot intrinsics; the code generator needs to see those.
-bool LowerIntrinsics::runOnFunction(Function &F) {
-  // Quick exit for functions that do not use GC.
-  if (!F.hasGC())
-    return false;
-
-  GCFunctionInfo &FI = getAnalysis<GCModuleInfo>().getFunctionInfo(F);
-  GCStrategy &S = FI.getStrategy();
-
-  bool MadeChange = false;
-
-  if (NeedsDefaultLoweringPass(S))
-    MadeChange |= PerformDefaultLowering(F, S);
-
-  bool UseCustomLoweringPass = NeedsCustomLoweringPass(S);
-  if (UseCustomLoweringPass)
-    MadeChange |= S.performCustomLowering(F);
-
-  // Custom lowering may modify the CFG, so dominators must be recomputed.
-  if (UseCustomLoweringPass) {
-    if (DominatorTreeWrapperPass *DTWP =
-            getAnalysisIfAvailable<DominatorTreeWrapperPass>())
-      DTWP->getDomTree().recalculate(F);
-  }
-
-  return MadeChange;
-}
-
-bool LowerIntrinsics::PerformDefaultLowering(Function &F, GCStrategy &S) {
-  bool LowerWr = !S.customWriteBarrier();
-  bool LowerRd = !S.customReadBarrier();
-  bool InitRoots = S.initializeRoots();
-
-  SmallVector<AllocaInst*, 32> Roots;
-
-  bool MadeChange = false;
-  for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
-    for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E;) {
-      if (IntrinsicInst *CI = dyn_cast<IntrinsicInst>(II++)) {
-        Function *F = CI->getCalledFunction();
-        switch (F->getIntrinsicID()) {
-        case Intrinsic::gcwrite:
-          if (LowerWr) {
-            // Replace a write barrier with a simple store.
-            Value *St = new StoreInst(CI->getArgOperand(0),
-                                      CI->getArgOperand(2), CI);
-            CI->replaceAllUsesWith(St);
-            CI->eraseFromParent();
-          }
-          break;
-        case Intrinsic::gcread:
-          if (LowerRd) {
-            // Replace a read barrier with a simple load.
-            Value *Ld = new LoadInst(CI->getArgOperand(1), "", CI);
-            Ld->takeName(CI);
-            CI->replaceAllUsesWith(Ld);
-            CI->eraseFromParent();
-          }
-          break;
-        case Intrinsic::gcroot:
-          if (InitRoots) {
-            // Initialize the GC root, but do not delete the intrinsic. The
-            // backend needs the intrinsic to flag the stack slot.
-            Roots.push_back(cast<AllocaInst>(
-                              CI->getArgOperand(0)->stripPointerCasts()));
-          }
-          break;
-        default:
-          continue;
-        }
-
-        MadeChange = true;
-      }
-    }
-  }
-
-  if (Roots.size())
-    MadeChange |= InsertRootInitializers(F, Roots.begin(), Roots.size());
-
-  return MadeChange;
-}
-
-// -----------------------------------------------------------------------------
-
-char GCMachineCodeAnalysis::ID = 0;
-char &llvm::GCMachineCodeAnalysisID = GCMachineCodeAnalysis::ID;
-
-INITIALIZE_PASS(GCMachineCodeAnalysis, "gc-analysis",
-                "Analyze Machine Code For Garbage Collection", false, false)
-
-GCMachineCodeAnalysis::GCMachineCodeAnalysis()
-  : MachineFunctionPass(ID) {}
-
-void GCMachineCodeAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
-  MachineFunctionPass::getAnalysisUsage(AU);
-  AU.setPreservesAll();
-  AU.addRequired<MachineModuleInfo>();
-  AU.addRequired<GCModuleInfo>();
-}
-
-MCSymbol *GCMachineCodeAnalysis::InsertLabel(MachineBasicBlock &MBB,
-                                             MachineBasicBlock::iterator MI,
-                                             DebugLoc DL) const {
-  MCSymbol *Label = MBB.getParent()->getContext().CreateTempSymbol();
-  BuildMI(MBB, MI, DL, TII->get(TargetOpcode::GC_LABEL)).addSym(Label);
-  return Label;
-}
-
-void GCMachineCodeAnalysis::VisitCallPoint(MachineBasicBlock::iterator CI) {
-  // Find the return address (next instruction), too, so as to bracket the call
-  // instruction.
-  MachineBasicBlock::iterator RAI = CI;
-  ++RAI;
-
-  if (FI->getStrategy().needsSafePoint(GC::PreCall)) {
-    MCSymbol* Label = InsertLabel(*CI->getParent(), CI, CI->getDebugLoc());
-    FI->addSafePoint(GC::PreCall, Label, CI->getDebugLoc());
-  }
-
-  if (FI->getStrategy().needsSafePoint(GC::PostCall)) {
-    MCSymbol* Label = InsertLabel(*CI->getParent(), RAI, CI->getDebugLoc());
-    FI->addSafePoint(GC::PostCall, Label, CI->getDebugLoc());
-  }
-}
-
-void GCMachineCodeAnalysis::FindSafePoints(MachineFunction &MF) {
-  for (MachineFunction::iterator BBI = MF.begin(),
-                                 BBE = MF.end(); BBI != BBE; ++BBI)
-    for (MachineBasicBlock::iterator MI = BBI->begin(),
-                                     ME = BBI->end(); MI != ME; ++MI)
-      if (MI->isCall())
-        VisitCallPoint(MI);
-}
-
-void GCMachineCodeAnalysis::FindStackOffsets(MachineFunction &MF) {
-  const TargetFrameLowering *TFI = TM->getSubtargetImpl()->getFrameLowering();
-  assert(TFI && "TargetRegisterInfo not available!");
-
-  for (GCFunctionInfo::roots_iterator RI = FI->roots_begin();
-       RI != FI->roots_end();) {
-    // If the root references a dead object, no need to keep it.
-    if (MF.getFrameInfo()->isDeadObjectIndex(RI->Num)) {
-      RI = FI->removeStackRoot(RI);
-    } else {
-      RI->StackOffset = TFI->getFrameIndexOffset(MF, RI->Num);
-      ++RI;
-    }
-  }
-}
-
-bool GCMachineCodeAnalysis::runOnMachineFunction(MachineFunction &MF) {
-  // Quick exit for functions that do not use GC.
-  if (!MF.getFunction()->hasGC())
-    return false;
-
-  FI = &getAnalysis<GCModuleInfo>().getFunctionInfo(*MF.getFunction());
-  if (!FI->getStrategy().needsSafePoints())
-    return false;
-
-  TM = &MF.getTarget();
-  MMI = &getAnalysis<MachineModuleInfo>();
-  TII = TM->getSubtargetImpl()->getInstrInfo();
-
-  // Find the size of the stack frame.
-  FI->setFrameSize(MF.getFrameInfo()->getStackSize());
-
-  // Find all safe points.
-  if (FI->getStrategy().customSafePoints()) {
-    FI->getStrategy().findCustomSafePoints(*FI, MF);
-  } else {
-    FindSafePoints(MF);
-  }
-
-  // Find the stack offsets for all roots.
-  FindStackOffsets(MF);
-
-  return false;
-}