Restoring authorship annotation for <[email protected]>. Commit 1 of 2.

1 files changed, 900 insertions, 900 deletions

diff --git a/contrib/libs/llvm12/lib/CodeGen/SafeStack.cpp b/contrib/libs/llvm12/lib/CodeGen/SafeStack.cpp
index 31797631c97..5f9fd6e66ab 100644
--- a/contrib/libs/llvm12/lib/CodeGen/SafeStack.cpp
+++ b/contrib/libs/llvm12/lib/CodeGen/SafeStack.cpp
@@ -1,918 +1,918 @@
-//===- SafeStack.cpp - Safe Stack Insertion -------------------------------===//
-//
-// 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 pass splits the stack into the safe stack (kept as-is for LLVM backend)
-// and the unsafe stack (explicitly allocated and managed through the runtime
-// support library).
-//
-// http://clang.llvm.org/docs/SafeStack.html
-//
-//===----------------------------------------------------------------------===//
-
-#include "SafeStackLayout.h"
-#include "llvm/ADT/APInt.h"
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/BitVector.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/Analysis/AssumptionCache.h"
-#include "llvm/Analysis/BranchProbabilityInfo.h"
-#include "llvm/Analysis/InlineCost.h"
-#include "llvm/Analysis/LoopInfo.h"
-#include "llvm/Analysis/ScalarEvolution.h"
-#include "llvm/Analysis/ScalarEvolutionExpressions.h"
-#include "llvm/Analysis/StackLifetime.h"
-#include "llvm/Analysis/TargetLibraryInfo.h"
-#include "llvm/CodeGen/TargetLowering.h"
-#include "llvm/CodeGen/TargetPassConfig.h"
-#include "llvm/CodeGen/TargetSubtargetInfo.h"
-#include "llvm/IR/Argument.h"
-#include "llvm/IR/Attributes.h"
-#include "llvm/IR/ConstantRange.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/DIBuilder.h"
-#include "llvm/IR/DataLayout.h"
-#include "llvm/IR/DerivedTypes.h"
-#include "llvm/IR/Dominators.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/InstIterator.h"
-#include "llvm/IR/Instruction.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/IntrinsicInst.h"
-#include "llvm/IR/Intrinsics.h"
-#include "llvm/IR/MDBuilder.h"
-#include "llvm/IR/Module.h"
-#include "llvm/IR/Type.h"
-#include "llvm/IR/Use.h"
-#include "llvm/IR/User.h"
-#include "llvm/IR/Value.h"
-#include "llvm/InitializePasses.h"
-#include "llvm/Pass.h"
-#include "llvm/Support/Casting.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/MathExtras.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Target/TargetMachine.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Transforms/Utils/Cloning.h"
-#include "llvm/Transforms/Utils/Local.h"
-#include <algorithm>
-#include <cassert>
-#include <cstdint>
-#include <string>
-#include <utility>
-
-using namespace llvm;
-using namespace llvm::safestack;
-
-#define DEBUG_TYPE "safe-stack"
-
-namespace llvm {
-
-STATISTIC(NumFunctions, "Total number of functions");
-STATISTIC(NumUnsafeStackFunctions, "Number of functions with unsafe stack");
-STATISTIC(NumUnsafeStackRestorePointsFunctions,
-          "Number of functions that use setjmp or exceptions");
-
-STATISTIC(NumAllocas, "Total number of allocas");
-STATISTIC(NumUnsafeStaticAllocas, "Number of unsafe static allocas");
-STATISTIC(NumUnsafeDynamicAllocas, "Number of unsafe dynamic allocas");
-STATISTIC(NumUnsafeByValArguments, "Number of unsafe byval arguments");
-STATISTIC(NumUnsafeStackRestorePoints, "Number of setjmps and landingpads");
-
-} // namespace llvm
-
-/// Use __safestack_pointer_address even if the platform has a faster way of
-/// access safe stack pointer.
-static cl::opt<bool>
-    SafeStackUsePointerAddress("safestack-use-pointer-address",
-                                  cl::init(false), cl::Hidden);
-
-// Disabled by default due to PR32143.
-static cl::opt<bool> ClColoring("safe-stack-coloring",
-                                cl::desc("enable safe stack coloring"),
-                                cl::Hidden, cl::init(false));
-
-namespace {
-
-/// Rewrite an SCEV expression for a memory access address to an expression that
-/// represents offset from the given alloca.
-///
-/// The implementation simply replaces all mentions of the alloca with zero.
-class AllocaOffsetRewriter : public SCEVRewriteVisitor<AllocaOffsetRewriter> {
-  const Value *AllocaPtr;
-
-public:
-  AllocaOffsetRewriter(ScalarEvolution &SE, const Value *AllocaPtr)
-      : SCEVRewriteVisitor(SE), AllocaPtr(AllocaPtr) {}
-
-  const SCEV *visitUnknown(const SCEVUnknown *Expr) {
-    if (Expr->getValue() == AllocaPtr)
-      return SE.getZero(Expr->getType());
-    return Expr;
-  }
-};
-
-/// The SafeStack pass splits the stack of each function into the safe
-/// stack, which is only accessed through memory safe dereferences (as
-/// determined statically), and the unsafe stack, which contains all
-/// local variables that are accessed in ways that we can't prove to
-/// be safe.
-class SafeStack {
-  Function &F;
-  const TargetLoweringBase &TL;
-  const DataLayout &DL;
-  ScalarEvolution &SE;
-
-  Type *StackPtrTy;
-  Type *IntPtrTy;
-  Type *Int32Ty;
-  Type *Int8Ty;
-
-  Value *UnsafeStackPtr = nullptr;
-
-  /// Unsafe stack alignment. Each stack frame must ensure that the stack is
-  /// aligned to this value. We need to re-align the unsafe stack if the
-  /// alignment of any object on the stack exceeds this value.
-  ///
-  /// 16 seems like a reasonable upper bound on the alignment of objects that we
-  /// might expect to appear on the stack on most common targets.
-  enum { StackAlignment = 16 };
-
-  /// Return the value of the stack canary.
-  Value *getStackGuard(IRBuilder<> &IRB, Function &F);
-
-  /// Load stack guard from the frame and check if it has changed.
+//===- SafeStack.cpp - Safe Stack Insertion -------------------------------===// 
+// 
+// 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 pass splits the stack into the safe stack (kept as-is for LLVM backend) 
+// and the unsafe stack (explicitly allocated and managed through the runtime 
+// support library). 
+// 
+// http://clang.llvm.org/docs/SafeStack.html 
+// 
+//===----------------------------------------------------------------------===// 
+ 
+#include "SafeStackLayout.h" 
+#include "llvm/ADT/APInt.h" 
+#include "llvm/ADT/ArrayRef.h" 
+#include "llvm/ADT/BitVector.h" 
+#include "llvm/ADT/SmallPtrSet.h" 
+#include "llvm/ADT/SmallVector.h" 
+#include "llvm/ADT/Statistic.h" 
+#include "llvm/Analysis/AssumptionCache.h" 
+#include "llvm/Analysis/BranchProbabilityInfo.h" 
+#include "llvm/Analysis/InlineCost.h" 
+#include "llvm/Analysis/LoopInfo.h" 
+#include "llvm/Analysis/ScalarEvolution.h" 
+#include "llvm/Analysis/ScalarEvolutionExpressions.h" 
+#include "llvm/Analysis/StackLifetime.h" 
+#include "llvm/Analysis/TargetLibraryInfo.h" 
+#include "llvm/CodeGen/TargetLowering.h" 
+#include "llvm/CodeGen/TargetPassConfig.h" 
+#include "llvm/CodeGen/TargetSubtargetInfo.h" 
+#include "llvm/IR/Argument.h" 
+#include "llvm/IR/Attributes.h" 
+#include "llvm/IR/ConstantRange.h" 
+#include "llvm/IR/Constants.h" 
+#include "llvm/IR/DIBuilder.h" 
+#include "llvm/IR/DataLayout.h" 
+#include "llvm/IR/DerivedTypes.h" 
+#include "llvm/IR/Dominators.h" 
+#include "llvm/IR/Function.h" 
+#include "llvm/IR/IRBuilder.h" 
+#include "llvm/IR/InstIterator.h" 
+#include "llvm/IR/Instruction.h" 
+#include "llvm/IR/Instructions.h" 
+#include "llvm/IR/IntrinsicInst.h" 
+#include "llvm/IR/Intrinsics.h" 
+#include "llvm/IR/MDBuilder.h" 
+#include "llvm/IR/Module.h" 
+#include "llvm/IR/Type.h" 
+#include "llvm/IR/Use.h" 
+#include "llvm/IR/User.h" 
+#include "llvm/IR/Value.h" 
+#include "llvm/InitializePasses.h" 
+#include "llvm/Pass.h" 
+#include "llvm/Support/Casting.h" 
+#include "llvm/Support/Debug.h" 
+#include "llvm/Support/ErrorHandling.h" 
+#include "llvm/Support/MathExtras.h" 
+#include "llvm/Support/raw_ostream.h" 
+#include "llvm/Target/TargetMachine.h" 
+#include "llvm/Transforms/Utils/BasicBlockUtils.h" 
+#include "llvm/Transforms/Utils/Cloning.h" 
+#include "llvm/Transforms/Utils/Local.h" 
+#include <algorithm> 
+#include <cassert> 
+#include <cstdint> 
+#include <string> 
+#include <utility> 
+ 
+using namespace llvm; 
+using namespace llvm::safestack; 
+ 
+#define DEBUG_TYPE "safe-stack" 
+ 
+namespace llvm { 
+ 
+STATISTIC(NumFunctions, "Total number of functions"); 
+STATISTIC(NumUnsafeStackFunctions, "Number of functions with unsafe stack"); 
+STATISTIC(NumUnsafeStackRestorePointsFunctions, 
+          "Number of functions that use setjmp or exceptions"); 
+ 
+STATISTIC(NumAllocas, "Total number of allocas"); 
+STATISTIC(NumUnsafeStaticAllocas, "Number of unsafe static allocas"); 
+STATISTIC(NumUnsafeDynamicAllocas, "Number of unsafe dynamic allocas"); 
+STATISTIC(NumUnsafeByValArguments, "Number of unsafe byval arguments"); 
+STATISTIC(NumUnsafeStackRestorePoints, "Number of setjmps and landingpads"); 
+ 
+} // namespace llvm 
+ 
+/// Use __safestack_pointer_address even if the platform has a faster way of 
+/// access safe stack pointer. 
+static cl::opt<bool> 
+    SafeStackUsePointerAddress("safestack-use-pointer-address", 
+                                  cl::init(false), cl::Hidden); 
+ 
+// Disabled by default due to PR32143. 
+static cl::opt<bool> ClColoring("safe-stack-coloring", 
+                                cl::desc("enable safe stack coloring"), 
+                                cl::Hidden, cl::init(false)); 
+ 
+namespace { 
+ 
+/// Rewrite an SCEV expression for a memory access address to an expression that 
+/// represents offset from the given alloca. 
+/// 
+/// The implementation simply replaces all mentions of the alloca with zero. 
+class AllocaOffsetRewriter : public SCEVRewriteVisitor<AllocaOffsetRewriter> { 
+  const Value *AllocaPtr; 
+ 
+public: 
+  AllocaOffsetRewriter(ScalarEvolution &SE, const Value *AllocaPtr) 
+      : SCEVRewriteVisitor(SE), AllocaPtr(AllocaPtr) {} 
+ 
+  const SCEV *visitUnknown(const SCEVUnknown *Expr) { 
+    if (Expr->getValue() == AllocaPtr) 
+      return SE.getZero(Expr->getType()); 
+    return Expr; 
+  } 
+}; 
+ 
+/// The SafeStack pass splits the stack of each function into the safe 
+/// stack, which is only accessed through memory safe dereferences (as 
+/// determined statically), and the unsafe stack, which contains all 
+/// local variables that are accessed in ways that we can't prove to 
+/// be safe. 
+class SafeStack { 
+  Function &F; 
+  const TargetLoweringBase &TL; 
+  const DataLayout &DL; 
+  ScalarEvolution &SE; 
+ 
+  Type *StackPtrTy; 
+  Type *IntPtrTy; 
+  Type *Int32Ty; 
+  Type *Int8Ty; 
+ 
+  Value *UnsafeStackPtr = nullptr; 
+ 
+  /// Unsafe stack alignment. Each stack frame must ensure that the stack is 
+  /// aligned to this value. We need to re-align the unsafe stack if the 
+  /// alignment of any object on the stack exceeds this value. 
+  /// 
+  /// 16 seems like a reasonable upper bound on the alignment of objects that we 
+  /// might expect to appear on the stack on most common targets. 
+  enum { StackAlignment = 16 }; 
+ 
+  /// Return the value of the stack canary. 
+  Value *getStackGuard(IRBuilder<> &IRB, Function &F); 
+ 
+  /// Load stack guard from the frame and check if it has changed. 
   void checkStackGuard(IRBuilder<> &IRB, Function &F, Instruction &RI,
-                       AllocaInst *StackGuardSlot, Value *StackGuard);
-
-  /// Find all static allocas, dynamic allocas, return instructions and
-  /// stack restore points (exception unwind blocks and setjmp calls) in the
-  /// given function and append them to the respective vectors.
-  void findInsts(Function &F, SmallVectorImpl<AllocaInst *> &StaticAllocas,
-                 SmallVectorImpl<AllocaInst *> &DynamicAllocas,
-                 SmallVectorImpl<Argument *> &ByValArguments,
+                       AllocaInst *StackGuardSlot, Value *StackGuard); 
+ 
+  /// Find all static allocas, dynamic allocas, return instructions and 
+  /// stack restore points (exception unwind blocks and setjmp calls) in the 
+  /// given function and append them to the respective vectors. 
+  void findInsts(Function &F, SmallVectorImpl<AllocaInst *> &StaticAllocas, 
+                 SmallVectorImpl<AllocaInst *> &DynamicAllocas, 
+                 SmallVectorImpl<Argument *> &ByValArguments, 
                  SmallVectorImpl<Instruction *> &Returns,
-                 SmallVectorImpl<Instruction *> &StackRestorePoints);
-
-  /// Calculate the allocation size of a given alloca. Returns 0 if the
-  /// size can not be statically determined.
-  uint64_t getStaticAllocaAllocationSize(const AllocaInst* AI);
-
-  /// Allocate space for all static allocas in \p StaticAllocas,
+                 SmallVectorImpl<Instruction *> &StackRestorePoints); 
+ 
+  /// Calculate the allocation size of a given alloca. Returns 0 if the 
+  /// size can not be statically determined. 
+  uint64_t getStaticAllocaAllocationSize(const AllocaInst* AI); 
+ 
+  /// Allocate space for all static allocas in \p StaticAllocas, 
   /// replace allocas with pointers into the unsafe stack.
-  ///
-  /// \returns A pointer to the top of the unsafe stack after all unsafe static
-  /// allocas are allocated.
-  Value *moveStaticAllocasToUnsafeStack(IRBuilder<> &IRB, Function &F,
-                                        ArrayRef<AllocaInst *> StaticAllocas,
-                                        ArrayRef<Argument *> ByValArguments,
-                                        Instruction *BasePointer,
-                                        AllocaInst *StackGuardSlot);
-
-  /// Generate code to restore the stack after all stack restore points
-  /// in \p StackRestorePoints.
-  ///
-  /// \returns A local variable in which to maintain the dynamic top of the
-  /// unsafe stack if needed.
-  AllocaInst *
-  createStackRestorePoints(IRBuilder<> &IRB, Function &F,
-                           ArrayRef<Instruction *> StackRestorePoints,
-                           Value *StaticTop, bool NeedDynamicTop);
-
-  /// Replace all allocas in \p DynamicAllocas with code to allocate
-  /// space dynamically on the unsafe stack and store the dynamic unsafe stack
-  /// top to \p DynamicTop if non-null.
-  void moveDynamicAllocasToUnsafeStack(Function &F, Value *UnsafeStackPtr,
-                                       AllocaInst *DynamicTop,
-                                       ArrayRef<AllocaInst *> DynamicAllocas);
-
-  bool IsSafeStackAlloca(const Value *AllocaPtr, uint64_t AllocaSize);
-
-  bool IsMemIntrinsicSafe(const MemIntrinsic *MI, const Use &U,
-                          const Value *AllocaPtr, uint64_t AllocaSize);
-  bool IsAccessSafe(Value *Addr, uint64_t Size, const Value *AllocaPtr,
-                    uint64_t AllocaSize);
-
-  bool ShouldInlinePointerAddress(CallInst &CI);
-  void TryInlinePointerAddress();
-
-public:
-  SafeStack(Function &F, const TargetLoweringBase &TL, const DataLayout &DL,
-            ScalarEvolution &SE)
-      : F(F), TL(TL), DL(DL), SE(SE),
-        StackPtrTy(Type::getInt8PtrTy(F.getContext())),
-        IntPtrTy(DL.getIntPtrType(F.getContext())),
-        Int32Ty(Type::getInt32Ty(F.getContext())),
-        Int8Ty(Type::getInt8Ty(F.getContext())) {}
-
-  // Run the transformation on the associated function.
-  // Returns whether the function was changed.
-  bool run();
-};
-
-uint64_t SafeStack::getStaticAllocaAllocationSize(const AllocaInst* AI) {
-  uint64_t Size = DL.getTypeAllocSize(AI->getAllocatedType());
-  if (AI->isArrayAllocation()) {
-    auto C = dyn_cast<ConstantInt>(AI->getArraySize());
-    if (!C)
-      return 0;
-    Size *= C->getZExtValue();
-  }
-  return Size;
-}
-
-bool SafeStack::IsAccessSafe(Value *Addr, uint64_t AccessSize,
-                             const Value *AllocaPtr, uint64_t AllocaSize) {
-  AllocaOffsetRewriter Rewriter(SE, AllocaPtr);
-  const SCEV *Expr = Rewriter.visit(SE.getSCEV(Addr));
-
-  uint64_t BitWidth = SE.getTypeSizeInBits(Expr->getType());
-  ConstantRange AccessStartRange = SE.getUnsignedRange(Expr);
-  ConstantRange SizeRange =
-      ConstantRange(APInt(BitWidth, 0), APInt(BitWidth, AccessSize));
-  ConstantRange AccessRange = AccessStartRange.add(SizeRange);
-  ConstantRange AllocaRange =
-      ConstantRange(APInt(BitWidth, 0), APInt(BitWidth, AllocaSize));
-  bool Safe = AllocaRange.contains(AccessRange);
-
-  LLVM_DEBUG(
-      dbgs() << "[SafeStack] "
-             << (isa<AllocaInst>(AllocaPtr) ? "Alloca " : "ByValArgument ")
-             << *AllocaPtr << "\n"
-             << "            Access " << *Addr << "\n"
-             << "            SCEV " << *Expr
-             << " U: " << SE.getUnsignedRange(Expr)
-             << ", S: " << SE.getSignedRange(Expr) << "\n"
-             << "            Range " << AccessRange << "\n"
-             << "            AllocaRange " << AllocaRange << "\n"
-             << "            " << (Safe ? "safe" : "unsafe") << "\n");
-
-  return Safe;
-}
-
-bool SafeStack::IsMemIntrinsicSafe(const MemIntrinsic *MI, const Use &U,
-                                   const Value *AllocaPtr,
-                                   uint64_t AllocaSize) {
-  if (auto MTI = dyn_cast<MemTransferInst>(MI)) {
-    if (MTI->getRawSource() != U && MTI->getRawDest() != U)
-      return true;
-  } else {
-    if (MI->getRawDest() != U)
-      return true;
-  }
-
-  const auto *Len = dyn_cast<ConstantInt>(MI->getLength());
-  // Non-constant size => unsafe. FIXME: try SCEV getRange.
-  if (!Len) return false;
-  return IsAccessSafe(U, Len->getZExtValue(), AllocaPtr, AllocaSize);
-}
-
-/// Check whether a given allocation must be put on the safe
-/// stack or not. The function analyzes all uses of AI and checks whether it is
-/// only accessed in a memory safe way (as decided statically).
-bool SafeStack::IsSafeStackAlloca(const Value *AllocaPtr, uint64_t AllocaSize) {
-  // Go through all uses of this alloca and check whether all accesses to the
-  // allocated object are statically known to be memory safe and, hence, the
-  // object can be placed on the safe stack.
-  SmallPtrSet<const Value *, 16> Visited;
-  SmallVector<const Value *, 8> WorkList;
-  WorkList.push_back(AllocaPtr);
-
-  // A DFS search through all uses of the alloca in bitcasts/PHI/GEPs/etc.
-  while (!WorkList.empty()) {
-    const Value *V = WorkList.pop_back_val();
-    for (const Use &UI : V->uses()) {
-      auto I = cast<const Instruction>(UI.getUser());
-      assert(V == UI.get());
-
-      switch (I->getOpcode()) {
-      case Instruction::Load:
-        if (!IsAccessSafe(UI, DL.getTypeStoreSize(I->getType()), AllocaPtr,
-                          AllocaSize))
-          return false;
-        break;
-
-      case Instruction::VAArg:
-        // "va-arg" from a pointer is safe.
-        break;
-      case Instruction::Store:
-        if (V == I->getOperand(0)) {
-          // Stored the pointer - conservatively assume it may be unsafe.
-          LLVM_DEBUG(dbgs()
-                     << "[SafeStack] Unsafe alloca: " << *AllocaPtr
-                     << "\n            store of address: " << *I << "\n");
-          return false;
-        }
-
-        if (!IsAccessSafe(UI, DL.getTypeStoreSize(I->getOperand(0)->getType()),
-                          AllocaPtr, AllocaSize))
-          return false;
-        break;
-
-      case Instruction::Ret:
-        // Information leak.
-        return false;
-
-      case Instruction::Call:
-      case Instruction::Invoke: {
-        const CallBase &CS = *cast<CallBase>(I);
-
-        if (I->isLifetimeStartOrEnd())
-          continue;
-
-        if (const MemIntrinsic *MI = dyn_cast<MemIntrinsic>(I)) {
-          if (!IsMemIntrinsicSafe(MI, UI, AllocaPtr, AllocaSize)) {
-            LLVM_DEBUG(dbgs()
-                       << "[SafeStack] Unsafe alloca: " << *AllocaPtr
-                       << "\n            unsafe memintrinsic: " << *I << "\n");
-            return false;
-          }
-          continue;
-        }
-
-        // LLVM 'nocapture' attribute is only set for arguments whose address
-        // is not stored, passed around, or used in any other non-trivial way.
-        // We assume that passing a pointer to an object as a 'nocapture
-        // readnone' argument is safe.
-        // FIXME: a more precise solution would require an interprocedural
-        // analysis here, which would look at all uses of an argument inside
-        // the function being called.
-        auto B = CS.arg_begin(), E = CS.arg_end();
-        for (auto A = B; A != E; ++A)
-          if (A->get() == V)
-            if (!(CS.doesNotCapture(A - B) && (CS.doesNotAccessMemory(A - B) ||
-                                               CS.doesNotAccessMemory()))) {
-              LLVM_DEBUG(dbgs() << "[SafeStack] Unsafe alloca: " << *AllocaPtr
-                                << "\n            unsafe call: " << *I << "\n");
-              return false;
-            }
-        continue;
-      }
-
-      default:
-        if (Visited.insert(I).second)
-          WorkList.push_back(cast<const Instruction>(I));
-      }
-    }
-  }
-
-  // All uses of the alloca are safe, we can place it on the safe stack.
-  return true;
-}
-
-Value *SafeStack::getStackGuard(IRBuilder<> &IRB, Function &F) {
-  Value *StackGuardVar = TL.getIRStackGuard(IRB);
-  if (!StackGuardVar)
-    StackGuardVar =
-        F.getParent()->getOrInsertGlobal("__stack_chk_guard", StackPtrTy);
-  return IRB.CreateLoad(StackPtrTy, StackGuardVar, "StackGuard");
-}
-
-void SafeStack::findInsts(Function &F,
-                          SmallVectorImpl<AllocaInst *> &StaticAllocas,
-                          SmallVectorImpl<AllocaInst *> &DynamicAllocas,
-                          SmallVectorImpl<Argument *> &ByValArguments,
+  /// 
+  /// \returns A pointer to the top of the unsafe stack after all unsafe static 
+  /// allocas are allocated. 
+  Value *moveStaticAllocasToUnsafeStack(IRBuilder<> &IRB, Function &F, 
+                                        ArrayRef<AllocaInst *> StaticAllocas, 
+                                        ArrayRef<Argument *> ByValArguments, 
+                                        Instruction *BasePointer, 
+                                        AllocaInst *StackGuardSlot); 
+ 
+  /// Generate code to restore the stack after all stack restore points 
+  /// in \p StackRestorePoints. 
+  /// 
+  /// \returns A local variable in which to maintain the dynamic top of the 
+  /// unsafe stack if needed. 
+  AllocaInst * 
+  createStackRestorePoints(IRBuilder<> &IRB, Function &F, 
+                           ArrayRef<Instruction *> StackRestorePoints, 
+                           Value *StaticTop, bool NeedDynamicTop); 
+ 
+  /// Replace all allocas in \p DynamicAllocas with code to allocate 
+  /// space dynamically on the unsafe stack and store the dynamic unsafe stack 
+  /// top to \p DynamicTop if non-null. 
+  void moveDynamicAllocasToUnsafeStack(Function &F, Value *UnsafeStackPtr, 
+                                       AllocaInst *DynamicTop, 
+                                       ArrayRef<AllocaInst *> DynamicAllocas); 
+ 
+  bool IsSafeStackAlloca(const Value *AllocaPtr, uint64_t AllocaSize); 
+ 
+  bool IsMemIntrinsicSafe(const MemIntrinsic *MI, const Use &U, 
+                          const Value *AllocaPtr, uint64_t AllocaSize); 
+  bool IsAccessSafe(Value *Addr, uint64_t Size, const Value *AllocaPtr, 
+                    uint64_t AllocaSize); 
+ 
+  bool ShouldInlinePointerAddress(CallInst &CI); 
+  void TryInlinePointerAddress(); 
+ 
+public: 
+  SafeStack(Function &F, const TargetLoweringBase &TL, const DataLayout &DL, 
+            ScalarEvolution &SE) 
+      : F(F), TL(TL), DL(DL), SE(SE), 
+        StackPtrTy(Type::getInt8PtrTy(F.getContext())), 
+        IntPtrTy(DL.getIntPtrType(F.getContext())), 
+        Int32Ty(Type::getInt32Ty(F.getContext())), 
+        Int8Ty(Type::getInt8Ty(F.getContext())) {} 
+ 
+  // Run the transformation on the associated function. 
+  // Returns whether the function was changed. 
+  bool run(); 
+}; 
+ 
+uint64_t SafeStack::getStaticAllocaAllocationSize(const AllocaInst* AI) { 
+  uint64_t Size = DL.getTypeAllocSize(AI->getAllocatedType()); 
+  if (AI->isArrayAllocation()) { 
+    auto C = dyn_cast<ConstantInt>(AI->getArraySize()); 
+    if (!C) 
+      return 0; 
+    Size *= C->getZExtValue(); 
+  } 
+  return Size; 
+} 
+ 
+bool SafeStack::IsAccessSafe(Value *Addr, uint64_t AccessSize, 
+                             const Value *AllocaPtr, uint64_t AllocaSize) { 
+  AllocaOffsetRewriter Rewriter(SE, AllocaPtr); 
+  const SCEV *Expr = Rewriter.visit(SE.getSCEV(Addr)); 
+ 
+  uint64_t BitWidth = SE.getTypeSizeInBits(Expr->getType()); 
+  ConstantRange AccessStartRange = SE.getUnsignedRange(Expr); 
+  ConstantRange SizeRange = 
+      ConstantRange(APInt(BitWidth, 0), APInt(BitWidth, AccessSize)); 
+  ConstantRange AccessRange = AccessStartRange.add(SizeRange); 
+  ConstantRange AllocaRange = 
+      ConstantRange(APInt(BitWidth, 0), APInt(BitWidth, AllocaSize)); 
+  bool Safe = AllocaRange.contains(AccessRange); 
+ 
+  LLVM_DEBUG( 
+      dbgs() << "[SafeStack] " 
+             << (isa<AllocaInst>(AllocaPtr) ? "Alloca " : "ByValArgument ") 
+             << *AllocaPtr << "\n" 
+             << "            Access " << *Addr << "\n" 
+             << "            SCEV " << *Expr 
+             << " U: " << SE.getUnsignedRange(Expr) 
+             << ", S: " << SE.getSignedRange(Expr) << "\n" 
+             << "            Range " << AccessRange << "\n" 
+             << "            AllocaRange " << AllocaRange << "\n" 
+             << "            " << (Safe ? "safe" : "unsafe") << "\n"); 
+ 
+  return Safe; 
+} 
+ 
+bool SafeStack::IsMemIntrinsicSafe(const MemIntrinsic *MI, const Use &U, 
+                                   const Value *AllocaPtr, 
+                                   uint64_t AllocaSize) { 
+  if (auto MTI = dyn_cast<MemTransferInst>(MI)) { 
+    if (MTI->getRawSource() != U && MTI->getRawDest() != U) 
+      return true; 
+  } else { 
+    if (MI->getRawDest() != U) 
+      return true; 
+  } 
+ 
+  const auto *Len = dyn_cast<ConstantInt>(MI->getLength()); 
+  // Non-constant size => unsafe. FIXME: try SCEV getRange. 
+  if (!Len) return false; 
+  return IsAccessSafe(U, Len->getZExtValue(), AllocaPtr, AllocaSize); 
+} 
+ 
+/// Check whether a given allocation must be put on the safe 
+/// stack or not. The function analyzes all uses of AI and checks whether it is 
+/// only accessed in a memory safe way (as decided statically). 
+bool SafeStack::IsSafeStackAlloca(const Value *AllocaPtr, uint64_t AllocaSize) { 
+  // Go through all uses of this alloca and check whether all accesses to the 
+  // allocated object are statically known to be memory safe and, hence, the 
+  // object can be placed on the safe stack. 
+  SmallPtrSet<const Value *, 16> Visited; 
+  SmallVector<const Value *, 8> WorkList; 
+  WorkList.push_back(AllocaPtr); 
+ 
+  // A DFS search through all uses of the alloca in bitcasts/PHI/GEPs/etc. 
+  while (!WorkList.empty()) { 
+    const Value *V = WorkList.pop_back_val(); 
+    for (const Use &UI : V->uses()) { 
+      auto I = cast<const Instruction>(UI.getUser()); 
+      assert(V == UI.get()); 
+ 
+      switch (I->getOpcode()) { 
+      case Instruction::Load: 
+        if (!IsAccessSafe(UI, DL.getTypeStoreSize(I->getType()), AllocaPtr, 
+                          AllocaSize)) 
+          return false; 
+        break; 
+ 
+      case Instruction::VAArg: 
+        // "va-arg" from a pointer is safe. 
+        break; 
+      case Instruction::Store: 
+        if (V == I->getOperand(0)) { 
+          // Stored the pointer - conservatively assume it may be unsafe. 
+          LLVM_DEBUG(dbgs() 
+                     << "[SafeStack] Unsafe alloca: " << *AllocaPtr 
+                     << "\n            store of address: " << *I << "\n"); 
+          return false; 
+        } 
+ 
+        if (!IsAccessSafe(UI, DL.getTypeStoreSize(I->getOperand(0)->getType()), 
+                          AllocaPtr, AllocaSize)) 
+          return false; 
+        break; 
+ 
+      case Instruction::Ret: 
+        // Information leak. 
+        return false; 
+ 
+      case Instruction::Call: 
+      case Instruction::Invoke: { 
+        const CallBase &CS = *cast<CallBase>(I); 
+ 
+        if (I->isLifetimeStartOrEnd()) 
+          continue; 
+ 
+        if (const MemIntrinsic *MI = dyn_cast<MemIntrinsic>(I)) { 
+          if (!IsMemIntrinsicSafe(MI, UI, AllocaPtr, AllocaSize)) { 
+            LLVM_DEBUG(dbgs() 
+                       << "[SafeStack] Unsafe alloca: " << *AllocaPtr 
+                       << "\n            unsafe memintrinsic: " << *I << "\n"); 
+            return false; 
+          } 
+          continue; 
+        } 
+ 
+        // LLVM 'nocapture' attribute is only set for arguments whose address 
+        // is not stored, passed around, or used in any other non-trivial way. 
+        // We assume that passing a pointer to an object as a 'nocapture 
+        // readnone' argument is safe. 
+        // FIXME: a more precise solution would require an interprocedural 
+        // analysis here, which would look at all uses of an argument inside 
+        // the function being called. 
+        auto B = CS.arg_begin(), E = CS.arg_end(); 
+        for (auto A = B; A != E; ++A) 
+          if (A->get() == V) 
+            if (!(CS.doesNotCapture(A - B) && (CS.doesNotAccessMemory(A - B) || 
+                                               CS.doesNotAccessMemory()))) { 
+              LLVM_DEBUG(dbgs() << "[SafeStack] Unsafe alloca: " << *AllocaPtr 
+                                << "\n            unsafe call: " << *I << "\n"); 
+              return false; 
+            } 
+        continue; 
+      } 
+ 
+      default: 
+        if (Visited.insert(I).second) 
+          WorkList.push_back(cast<const Instruction>(I)); 
+      } 
+    } 
+  } 
+ 
+  // All uses of the alloca are safe, we can place it on the safe stack. 
+  return true; 
+} 
+ 
+Value *SafeStack::getStackGuard(IRBuilder<> &IRB, Function &F) { 
+  Value *StackGuardVar = TL.getIRStackGuard(IRB); 
+  if (!StackGuardVar) 
+    StackGuardVar = 
+        F.getParent()->getOrInsertGlobal("__stack_chk_guard", StackPtrTy); 
+  return IRB.CreateLoad(StackPtrTy, StackGuardVar, "StackGuard"); 
+} 
+ 
+void SafeStack::findInsts(Function &F, 
+                          SmallVectorImpl<AllocaInst *> &StaticAllocas, 
+                          SmallVectorImpl<AllocaInst *> &DynamicAllocas, 
+                          SmallVectorImpl<Argument *> &ByValArguments, 
                           SmallVectorImpl<Instruction *> &Returns,
-                          SmallVectorImpl<Instruction *> &StackRestorePoints) {
-  for (Instruction &I : instructions(&F)) {
-    if (auto AI = dyn_cast<AllocaInst>(&I)) {
-      ++NumAllocas;
-
-      uint64_t Size = getStaticAllocaAllocationSize(AI);
-      if (IsSafeStackAlloca(AI, Size))
-        continue;
-
-      if (AI->isStaticAlloca()) {
-        ++NumUnsafeStaticAllocas;
-        StaticAllocas.push_back(AI);
-      } else {
-        ++NumUnsafeDynamicAllocas;
-        DynamicAllocas.push_back(AI);
-      }
-    } else if (auto RI = dyn_cast<ReturnInst>(&I)) {
+                          SmallVectorImpl<Instruction *> &StackRestorePoints) { 
+  for (Instruction &I : instructions(&F)) { 
+    if (auto AI = dyn_cast<AllocaInst>(&I)) { 
+      ++NumAllocas; 
+ 
+      uint64_t Size = getStaticAllocaAllocationSize(AI); 
+      if (IsSafeStackAlloca(AI, Size)) 
+        continue; 
+ 
+      if (AI->isStaticAlloca()) { 
+        ++NumUnsafeStaticAllocas; 
+        StaticAllocas.push_back(AI); 
+      } else { 
+        ++NumUnsafeDynamicAllocas; 
+        DynamicAllocas.push_back(AI); 
+      } 
+    } else if (auto RI = dyn_cast<ReturnInst>(&I)) { 
       if (CallInst *CI = I.getParent()->getTerminatingMustTailCall())
         Returns.push_back(CI);
       else
         Returns.push_back(RI);
-    } else if (auto CI = dyn_cast<CallInst>(&I)) {
-      // setjmps require stack restore.
-      if (CI->getCalledFunction() && CI->canReturnTwice())
-        StackRestorePoints.push_back(CI);
-    } else if (auto LP = dyn_cast<LandingPadInst>(&I)) {
-      // Exception landing pads require stack restore.
-      StackRestorePoints.push_back(LP);
-    } else if (auto II = dyn_cast<IntrinsicInst>(&I)) {
-      if (II->getIntrinsicID() == Intrinsic::gcroot)
-        report_fatal_error(
-            "gcroot intrinsic not compatible with safestack attribute");
-    }
-  }
-  for (Argument &Arg : F.args()) {
-    if (!Arg.hasByValAttr())
-      continue;
-    uint64_t Size =
-        DL.getTypeStoreSize(Arg.getType()->getPointerElementType());
-    if (IsSafeStackAlloca(&Arg, Size))
-      continue;
-
-    ++NumUnsafeByValArguments;
-    ByValArguments.push_back(&Arg);
-  }
-}
-
-AllocaInst *
-SafeStack::createStackRestorePoints(IRBuilder<> &IRB, Function &F,
-                                    ArrayRef<Instruction *> StackRestorePoints,
-                                    Value *StaticTop, bool NeedDynamicTop) {
-  assert(StaticTop && "The stack top isn't set.");
-
-  if (StackRestorePoints.empty())
-    return nullptr;
-
-  // We need the current value of the shadow stack pointer to restore
-  // after longjmp or exception catching.
-
-  // FIXME: On some platforms this could be handled by the longjmp/exception
-  // runtime itself.
-
-  AllocaInst *DynamicTop = nullptr;
-  if (NeedDynamicTop) {
-    // If we also have dynamic alloca's, the stack pointer value changes
-    // throughout the function. For now we store it in an alloca.
-    DynamicTop = IRB.CreateAlloca(StackPtrTy, /*ArraySize=*/nullptr,
-                                  "unsafe_stack_dynamic_ptr");
-    IRB.CreateStore(StaticTop, DynamicTop);
-  }
-
-  // Restore current stack pointer after longjmp/exception catch.
-  for (Instruction *I : StackRestorePoints) {
-    ++NumUnsafeStackRestorePoints;
-
-    IRB.SetInsertPoint(I->getNextNode());
-    Value *CurrentTop =
-        DynamicTop ? IRB.CreateLoad(StackPtrTy, DynamicTop) : StaticTop;
-    IRB.CreateStore(CurrentTop, UnsafeStackPtr);
-  }
-
-  return DynamicTop;
-}
-
+    } else if (auto CI = dyn_cast<CallInst>(&I)) { 
+      // setjmps require stack restore. 
+      if (CI->getCalledFunction() && CI->canReturnTwice()) 
+        StackRestorePoints.push_back(CI); 
+    } else if (auto LP = dyn_cast<LandingPadInst>(&I)) { 
+      // Exception landing pads require stack restore. 
+      StackRestorePoints.push_back(LP); 
+    } else if (auto II = dyn_cast<IntrinsicInst>(&I)) { 
+      if (II->getIntrinsicID() == Intrinsic::gcroot) 
+        report_fatal_error( 
+            "gcroot intrinsic not compatible with safestack attribute"); 
+    } 
+  } 
+  for (Argument &Arg : F.args()) { 
+    if (!Arg.hasByValAttr()) 
+      continue; 
+    uint64_t Size = 
+        DL.getTypeStoreSize(Arg.getType()->getPointerElementType()); 
+    if (IsSafeStackAlloca(&Arg, Size)) 
+      continue; 
+ 
+    ++NumUnsafeByValArguments; 
+    ByValArguments.push_back(&Arg); 
+  } 
+} 
+ 
+AllocaInst * 
+SafeStack::createStackRestorePoints(IRBuilder<> &IRB, Function &F, 
+                                    ArrayRef<Instruction *> StackRestorePoints, 
+                                    Value *StaticTop, bool NeedDynamicTop) { 
+  assert(StaticTop && "The stack top isn't set."); 
+ 
+  if (StackRestorePoints.empty()) 
+    return nullptr; 
+ 
+  // We need the current value of the shadow stack pointer to restore 
+  // after longjmp or exception catching. 
+ 
+  // FIXME: On some platforms this could be handled by the longjmp/exception 
+  // runtime itself. 
+ 
+  AllocaInst *DynamicTop = nullptr; 
+  if (NeedDynamicTop) { 
+    // If we also have dynamic alloca's, the stack pointer value changes 
+    // throughout the function. For now we store it in an alloca. 
+    DynamicTop = IRB.CreateAlloca(StackPtrTy, /*ArraySize=*/nullptr, 
+                                  "unsafe_stack_dynamic_ptr"); 
+    IRB.CreateStore(StaticTop, DynamicTop); 
+  } 
+ 
+  // Restore current stack pointer after longjmp/exception catch. 
+  for (Instruction *I : StackRestorePoints) { 
+    ++NumUnsafeStackRestorePoints; 
+ 
+    IRB.SetInsertPoint(I->getNextNode()); 
+    Value *CurrentTop = 
+        DynamicTop ? IRB.CreateLoad(StackPtrTy, DynamicTop) : StaticTop; 
+    IRB.CreateStore(CurrentTop, UnsafeStackPtr); 
+  } 
+ 
+  return DynamicTop; 
+} 
+ 
 void SafeStack::checkStackGuard(IRBuilder<> &IRB, Function &F, Instruction &RI,
-                                AllocaInst *StackGuardSlot, Value *StackGuard) {
-  Value *V = IRB.CreateLoad(StackPtrTy, StackGuardSlot);
-  Value *Cmp = IRB.CreateICmpNE(StackGuard, V);
-
-  auto SuccessProb = BranchProbabilityInfo::getBranchProbStackProtector(true);
-  auto FailureProb = BranchProbabilityInfo::getBranchProbStackProtector(false);
-  MDNode *Weights = MDBuilder(F.getContext())
-                        .createBranchWeights(SuccessProb.getNumerator(),
-                                             FailureProb.getNumerator());
-  Instruction *CheckTerm =
-      SplitBlockAndInsertIfThen(Cmp, &RI,
-                                /* Unreachable */ true, Weights);
-  IRBuilder<> IRBFail(CheckTerm);
-  // FIXME: respect -fsanitize-trap / -ftrap-function here?
-  FunctionCallee StackChkFail =
-      F.getParent()->getOrInsertFunction("__stack_chk_fail", IRB.getVoidTy());
-  IRBFail.CreateCall(StackChkFail, {});
-}
-
-/// We explicitly compute and set the unsafe stack layout for all unsafe
-/// static alloca instructions. We save the unsafe "base pointer" in the
-/// prologue into a local variable and restore it in the epilogue.
-Value *SafeStack::moveStaticAllocasToUnsafeStack(
-    IRBuilder<> &IRB, Function &F, ArrayRef<AllocaInst *> StaticAllocas,
+                                AllocaInst *StackGuardSlot, Value *StackGuard) { 
+  Value *V = IRB.CreateLoad(StackPtrTy, StackGuardSlot); 
+  Value *Cmp = IRB.CreateICmpNE(StackGuard, V); 
+ 
+  auto SuccessProb = BranchProbabilityInfo::getBranchProbStackProtector(true); 
+  auto FailureProb = BranchProbabilityInfo::getBranchProbStackProtector(false); 
+  MDNode *Weights = MDBuilder(F.getContext()) 
+                        .createBranchWeights(SuccessProb.getNumerator(), 
+                                             FailureProb.getNumerator()); 
+  Instruction *CheckTerm = 
+      SplitBlockAndInsertIfThen(Cmp, &RI, 
+                                /* Unreachable */ true, Weights); 
+  IRBuilder<> IRBFail(CheckTerm); 
+  // FIXME: respect -fsanitize-trap / -ftrap-function here? 
+  FunctionCallee StackChkFail = 
+      F.getParent()->getOrInsertFunction("__stack_chk_fail", IRB.getVoidTy()); 
+  IRBFail.CreateCall(StackChkFail, {}); 
+} 
+ 
+/// We explicitly compute and set the unsafe stack layout for all unsafe 
+/// static alloca instructions. We save the unsafe "base pointer" in the 
+/// prologue into a local variable and restore it in the epilogue. 
+Value *SafeStack::moveStaticAllocasToUnsafeStack( 
+    IRBuilder<> &IRB, Function &F, ArrayRef<AllocaInst *> StaticAllocas, 
     ArrayRef<Argument *> ByValArguments, Instruction *BasePointer,
     AllocaInst *StackGuardSlot) {
-  if (StaticAllocas.empty() && ByValArguments.empty())
-    return BasePointer;
-
-  DIBuilder DIB(*F.getParent());
-
-  StackLifetime SSC(F, StaticAllocas, StackLifetime::LivenessType::May);
-  static const StackLifetime::LiveRange NoColoringRange(1, true);
-  if (ClColoring)
-    SSC.run();
-
-  for (auto *I : SSC.getMarkers()) {
-    auto *Op = dyn_cast<Instruction>(I->getOperand(1));
-    const_cast<IntrinsicInst *>(I)->eraseFromParent();
-    // Remove the operand bitcast, too, if it has no more uses left.
-    if (Op && Op->use_empty())
-      Op->eraseFromParent();
-  }
-
-  // Unsafe stack always grows down.
-  StackLayout SSL(StackAlignment);
-  if (StackGuardSlot) {
-    Type *Ty = StackGuardSlot->getAllocatedType();
-    unsigned Align =
-        std::max(DL.getPrefTypeAlignment(Ty), StackGuardSlot->getAlignment());
-    SSL.addObject(StackGuardSlot, getStaticAllocaAllocationSize(StackGuardSlot),
-                  Align, SSC.getFullLiveRange());
-  }
-
-  for (Argument *Arg : ByValArguments) {
-    Type *Ty = Arg->getType()->getPointerElementType();
-    uint64_t Size = DL.getTypeStoreSize(Ty);
-    if (Size == 0)
-      Size = 1; // Don't create zero-sized stack objects.
-
-    // Ensure the object is properly aligned.
-    unsigned Align = std::max((unsigned)DL.getPrefTypeAlignment(Ty),
-                              Arg->getParamAlignment());
-    SSL.addObject(Arg, Size, Align, SSC.getFullLiveRange());
-  }
-
-  for (AllocaInst *AI : StaticAllocas) {
-    Type *Ty = AI->getAllocatedType();
-    uint64_t Size = getStaticAllocaAllocationSize(AI);
-    if (Size == 0)
-      Size = 1; // Don't create zero-sized stack objects.
-
-    // Ensure the object is properly aligned.
-    unsigned Align =
-        std::max((unsigned)DL.getPrefTypeAlignment(Ty), AI->getAlignment());
-
-    SSL.addObject(AI, Size, Align,
-                  ClColoring ? SSC.getLiveRange(AI) : NoColoringRange);
-  }
-
-  SSL.computeLayout();
-  unsigned FrameAlignment = SSL.getFrameAlignment();
-
-  // FIXME: tell SSL that we start at a less-then-MaxAlignment aligned location
-  // (AlignmentSkew).
-  if (FrameAlignment > StackAlignment) {
-    // Re-align the base pointer according to the max requested alignment.
-    assert(isPowerOf2_32(FrameAlignment));
-    IRB.SetInsertPoint(BasePointer->getNextNode());
-    BasePointer = cast<Instruction>(IRB.CreateIntToPtr(
-        IRB.CreateAnd(IRB.CreatePtrToInt(BasePointer, IntPtrTy),
-                      ConstantInt::get(IntPtrTy, ~uint64_t(FrameAlignment - 1))),
-        StackPtrTy));
-  }
-
-  IRB.SetInsertPoint(BasePointer->getNextNode());
-
-  if (StackGuardSlot) {
-    unsigned Offset = SSL.getObjectOffset(StackGuardSlot);
-    Value *Off = IRB.CreateGEP(Int8Ty, BasePointer, // BasePointer is i8*
-                               ConstantInt::get(Int32Ty, -Offset));
-    Value *NewAI =
-        IRB.CreateBitCast(Off, StackGuardSlot->getType(), "StackGuardSlot");
-
-    // Replace alloc with the new location.
-    StackGuardSlot->replaceAllUsesWith(NewAI);
-    StackGuardSlot->eraseFromParent();
-  }
-
-  for (Argument *Arg : ByValArguments) {
-    unsigned Offset = SSL.getObjectOffset(Arg);
-    MaybeAlign Align(SSL.getObjectAlignment(Arg));
-    Type *Ty = Arg->getType()->getPointerElementType();
-
-    uint64_t Size = DL.getTypeStoreSize(Ty);
-    if (Size == 0)
-      Size = 1; // Don't create zero-sized stack objects.
-
-    Value *Off = IRB.CreateGEP(Int8Ty, BasePointer, // BasePointer is i8*
-                               ConstantInt::get(Int32Ty, -Offset));
-    Value *NewArg = IRB.CreateBitCast(Off, Arg->getType(),
-                                     Arg->getName() + ".unsafe-byval");
-
-    // Replace alloc with the new location.
-    replaceDbgDeclare(Arg, BasePointer, DIB, DIExpression::ApplyOffset,
-                      -Offset);
-    Arg->replaceAllUsesWith(NewArg);
-    IRB.SetInsertPoint(cast<Instruction>(NewArg)->getNextNode());
-    IRB.CreateMemCpy(Off, Align, Arg, Arg->getParamAlign(), Size);
-  }
-
-  // Allocate space for every unsafe static AllocaInst on the unsafe stack.
-  for (AllocaInst *AI : StaticAllocas) {
-    IRB.SetInsertPoint(AI);
-    unsigned Offset = SSL.getObjectOffset(AI);
-
-    replaceDbgDeclare(AI, BasePointer, DIB, DIExpression::ApplyOffset, -Offset);
-    replaceDbgValueForAlloca(AI, BasePointer, DIB, -Offset);
-
-    // Replace uses of the alloca with the new location.
-    // Insert address calculation close to each use to work around PR27844.
-    std::string Name = std::string(AI->getName()) + ".unsafe";
-    while (!AI->use_empty()) {
-      Use &U = *AI->use_begin();
-      Instruction *User = cast<Instruction>(U.getUser());
-
-      Instruction *InsertBefore;
-      if (auto *PHI = dyn_cast<PHINode>(User))
-        InsertBefore = PHI->getIncomingBlock(U)->getTerminator();
-      else
-        InsertBefore = User;
-
-      IRBuilder<> IRBUser(InsertBefore);
-      Value *Off = IRBUser.CreateGEP(Int8Ty, BasePointer, // BasePointer is i8*
-                                     ConstantInt::get(Int32Ty, -Offset));
-      Value *Replacement = IRBUser.CreateBitCast(Off, AI->getType(), Name);
-
-      if (auto *PHI = dyn_cast<PHINode>(User))
-        // PHI nodes may have multiple incoming edges from the same BB (why??),
-        // all must be updated at once with the same incoming value.
-        PHI->setIncomingValueForBlock(PHI->getIncomingBlock(U), Replacement);
-      else
-        U.set(Replacement);
-    }
-
-    AI->eraseFromParent();
-  }
-
-  // Re-align BasePointer so that our callees would see it aligned as
-  // expected.
-  // FIXME: no need to update BasePointer in leaf functions.
-  unsigned FrameSize = alignTo(SSL.getFrameSize(), StackAlignment);
-
-  // Update shadow stack pointer in the function epilogue.
-  IRB.SetInsertPoint(BasePointer->getNextNode());
-
-  Value *StaticTop =
-      IRB.CreateGEP(Int8Ty, BasePointer, ConstantInt::get(Int32Ty, -FrameSize),
-                    "unsafe_stack_static_top");
-  IRB.CreateStore(StaticTop, UnsafeStackPtr);
-  return StaticTop;
-}
-
-void SafeStack::moveDynamicAllocasToUnsafeStack(
-    Function &F, Value *UnsafeStackPtr, AllocaInst *DynamicTop,
-    ArrayRef<AllocaInst *> DynamicAllocas) {
-  DIBuilder DIB(*F.getParent());
-
-  for (AllocaInst *AI : DynamicAllocas) {
-    IRBuilder<> IRB(AI);
-
-    // Compute the new SP value (after AI).
-    Value *ArraySize = AI->getArraySize();
-    if (ArraySize->getType() != IntPtrTy)
-      ArraySize = IRB.CreateIntCast(ArraySize, IntPtrTy, false);
-
-    Type *Ty = AI->getAllocatedType();
-    uint64_t TySize = DL.getTypeAllocSize(Ty);
-    Value *Size = IRB.CreateMul(ArraySize, ConstantInt::get(IntPtrTy, TySize));
-
-    Value *SP = IRB.CreatePtrToInt(IRB.CreateLoad(StackPtrTy, UnsafeStackPtr),
-                                   IntPtrTy);
-    SP = IRB.CreateSub(SP, Size);
-
-    // Align the SP value to satisfy the AllocaInst, type and stack alignments.
-    unsigned Align = std::max(
-        std::max((unsigned)DL.getPrefTypeAlignment(Ty), AI->getAlignment()),
-        (unsigned)StackAlignment);
-
-    assert(isPowerOf2_32(Align));
-    Value *NewTop = IRB.CreateIntToPtr(
-        IRB.CreateAnd(SP, ConstantInt::get(IntPtrTy, ~uint64_t(Align - 1))),
-        StackPtrTy);
-
-    // Save the stack pointer.
-    IRB.CreateStore(NewTop, UnsafeStackPtr);
-    if (DynamicTop)
-      IRB.CreateStore(NewTop, DynamicTop);
-
-    Value *NewAI = IRB.CreatePointerCast(NewTop, AI->getType());
-    if (AI->hasName() && isa<Instruction>(NewAI))
-      NewAI->takeName(AI);
-
-    replaceDbgDeclare(AI, NewAI, DIB, DIExpression::ApplyOffset, 0);
-    AI->replaceAllUsesWith(NewAI);
-    AI->eraseFromParent();
-  }
-
-  if (!DynamicAllocas.empty()) {
-    // Now go through the instructions again, replacing stacksave/stackrestore.
-    for (inst_iterator It = inst_begin(&F), Ie = inst_end(&F); It != Ie;) {
-      Instruction *I = &*(It++);
-      auto II = dyn_cast<IntrinsicInst>(I);
-      if (!II)
-        continue;
-
-      if (II->getIntrinsicID() == Intrinsic::stacksave) {
-        IRBuilder<> IRB(II);
-        Instruction *LI = IRB.CreateLoad(StackPtrTy, UnsafeStackPtr);
-        LI->takeName(II);
-        II->replaceAllUsesWith(LI);
-        II->eraseFromParent();
-      } else if (II->getIntrinsicID() == Intrinsic::stackrestore) {
-        IRBuilder<> IRB(II);
-        Instruction *SI = IRB.CreateStore(II->getArgOperand(0), UnsafeStackPtr);
-        SI->takeName(II);
-        assert(II->use_empty());
-        II->eraseFromParent();
-      }
-    }
-  }
-}
-
-bool SafeStack::ShouldInlinePointerAddress(CallInst &CI) {
-  Function *Callee = CI.getCalledFunction();
-  if (CI.hasFnAttr(Attribute::AlwaysInline) &&
-      isInlineViable(*Callee).isSuccess())
-    return true;
-  if (Callee->isInterposable() || Callee->hasFnAttribute(Attribute::NoInline) ||
-      CI.isNoInline())
-    return false;
-  return true;
-}
-
-void SafeStack::TryInlinePointerAddress() {
-  auto *CI = dyn_cast<CallInst>(UnsafeStackPtr);
-  if (!CI)
-    return;
-
-  if(F.hasOptNone())
-    return;
-
-  Function *Callee = CI->getCalledFunction();
-  if (!Callee || Callee->isDeclaration())
-    return;
-
-  if (!ShouldInlinePointerAddress(*CI))
-    return;
-
-  InlineFunctionInfo IFI;
-  InlineFunction(*CI, IFI);
-}
-
-bool SafeStack::run() {
-  assert(F.hasFnAttribute(Attribute::SafeStack) &&
-         "Can't run SafeStack on a function without the attribute");
-  assert(!F.isDeclaration() && "Can't run SafeStack on a function declaration");
-
-  ++NumFunctions;
-
-  SmallVector<AllocaInst *, 16> StaticAllocas;
-  SmallVector<AllocaInst *, 4> DynamicAllocas;
-  SmallVector<Argument *, 4> ByValArguments;
+  if (StaticAllocas.empty() && ByValArguments.empty()) 
+    return BasePointer; 
+ 
+  DIBuilder DIB(*F.getParent()); 
+ 
+  StackLifetime SSC(F, StaticAllocas, StackLifetime::LivenessType::May); 
+  static const StackLifetime::LiveRange NoColoringRange(1, true); 
+  if (ClColoring) 
+    SSC.run(); 
+ 
+  for (auto *I : SSC.getMarkers()) { 
+    auto *Op = dyn_cast<Instruction>(I->getOperand(1)); 
+    const_cast<IntrinsicInst *>(I)->eraseFromParent(); 
+    // Remove the operand bitcast, too, if it has no more uses left. 
+    if (Op && Op->use_empty()) 
+      Op->eraseFromParent(); 
+  } 
+ 
+  // Unsafe stack always grows down. 
+  StackLayout SSL(StackAlignment); 
+  if (StackGuardSlot) { 
+    Type *Ty = StackGuardSlot->getAllocatedType(); 
+    unsigned Align = 
+        std::max(DL.getPrefTypeAlignment(Ty), StackGuardSlot->getAlignment()); 
+    SSL.addObject(StackGuardSlot, getStaticAllocaAllocationSize(StackGuardSlot), 
+                  Align, SSC.getFullLiveRange()); 
+  } 
+ 
+  for (Argument *Arg : ByValArguments) { 
+    Type *Ty = Arg->getType()->getPointerElementType(); 
+    uint64_t Size = DL.getTypeStoreSize(Ty); 
+    if (Size == 0) 
+      Size = 1; // Don't create zero-sized stack objects. 
+ 
+    // Ensure the object is properly aligned. 
+    unsigned Align = std::max((unsigned)DL.getPrefTypeAlignment(Ty), 
+                              Arg->getParamAlignment()); 
+    SSL.addObject(Arg, Size, Align, SSC.getFullLiveRange()); 
+  } 
+ 
+  for (AllocaInst *AI : StaticAllocas) { 
+    Type *Ty = AI->getAllocatedType(); 
+    uint64_t Size = getStaticAllocaAllocationSize(AI); 
+    if (Size == 0) 
+      Size = 1; // Don't create zero-sized stack objects. 
+ 
+    // Ensure the object is properly aligned. 
+    unsigned Align = 
+        std::max((unsigned)DL.getPrefTypeAlignment(Ty), AI->getAlignment()); 
+ 
+    SSL.addObject(AI, Size, Align, 
+                  ClColoring ? SSC.getLiveRange(AI) : NoColoringRange); 
+  } 
+ 
+  SSL.computeLayout(); 
+  unsigned FrameAlignment = SSL.getFrameAlignment(); 
+ 
+  // FIXME: tell SSL that we start at a less-then-MaxAlignment aligned location 
+  // (AlignmentSkew). 
+  if (FrameAlignment > StackAlignment) { 
+    // Re-align the base pointer according to the max requested alignment. 
+    assert(isPowerOf2_32(FrameAlignment)); 
+    IRB.SetInsertPoint(BasePointer->getNextNode()); 
+    BasePointer = cast<Instruction>(IRB.CreateIntToPtr( 
+        IRB.CreateAnd(IRB.CreatePtrToInt(BasePointer, IntPtrTy), 
+                      ConstantInt::get(IntPtrTy, ~uint64_t(FrameAlignment - 1))), 
+        StackPtrTy)); 
+  } 
+ 
+  IRB.SetInsertPoint(BasePointer->getNextNode()); 
+ 
+  if (StackGuardSlot) { 
+    unsigned Offset = SSL.getObjectOffset(StackGuardSlot); 
+    Value *Off = IRB.CreateGEP(Int8Ty, BasePointer, // BasePointer is i8* 
+                               ConstantInt::get(Int32Ty, -Offset)); 
+    Value *NewAI = 
+        IRB.CreateBitCast(Off, StackGuardSlot->getType(), "StackGuardSlot"); 
+ 
+    // Replace alloc with the new location. 
+    StackGuardSlot->replaceAllUsesWith(NewAI); 
+    StackGuardSlot->eraseFromParent(); 
+  } 
+ 
+  for (Argument *Arg : ByValArguments) { 
+    unsigned Offset = SSL.getObjectOffset(Arg); 
+    MaybeAlign Align(SSL.getObjectAlignment(Arg)); 
+    Type *Ty = Arg->getType()->getPointerElementType(); 
+ 
+    uint64_t Size = DL.getTypeStoreSize(Ty); 
+    if (Size == 0) 
+      Size = 1; // Don't create zero-sized stack objects. 
+ 
+    Value *Off = IRB.CreateGEP(Int8Ty, BasePointer, // BasePointer is i8* 
+                               ConstantInt::get(Int32Ty, -Offset)); 
+    Value *NewArg = IRB.CreateBitCast(Off, Arg->getType(), 
+                                     Arg->getName() + ".unsafe-byval"); 
+ 
+    // Replace alloc with the new location. 
+    replaceDbgDeclare(Arg, BasePointer, DIB, DIExpression::ApplyOffset, 
+                      -Offset); 
+    Arg->replaceAllUsesWith(NewArg); 
+    IRB.SetInsertPoint(cast<Instruction>(NewArg)->getNextNode()); 
+    IRB.CreateMemCpy(Off, Align, Arg, Arg->getParamAlign(), Size); 
+  } 
+ 
+  // Allocate space for every unsafe static AllocaInst on the unsafe stack. 
+  for (AllocaInst *AI : StaticAllocas) { 
+    IRB.SetInsertPoint(AI); 
+    unsigned Offset = SSL.getObjectOffset(AI); 
+ 
+    replaceDbgDeclare(AI, BasePointer, DIB, DIExpression::ApplyOffset, -Offset); 
+    replaceDbgValueForAlloca(AI, BasePointer, DIB, -Offset); 
+ 
+    // Replace uses of the alloca with the new location. 
+    // Insert address calculation close to each use to work around PR27844. 
+    std::string Name = std::string(AI->getName()) + ".unsafe"; 
+    while (!AI->use_empty()) { 
+      Use &U = *AI->use_begin(); 
+      Instruction *User = cast<Instruction>(U.getUser()); 
+ 
+      Instruction *InsertBefore; 
+      if (auto *PHI = dyn_cast<PHINode>(User)) 
+        InsertBefore = PHI->getIncomingBlock(U)->getTerminator(); 
+      else 
+        InsertBefore = User; 
+ 
+      IRBuilder<> IRBUser(InsertBefore); 
+      Value *Off = IRBUser.CreateGEP(Int8Ty, BasePointer, // BasePointer is i8* 
+                                     ConstantInt::get(Int32Ty, -Offset)); 
+      Value *Replacement = IRBUser.CreateBitCast(Off, AI->getType(), Name); 
+ 
+      if (auto *PHI = dyn_cast<PHINode>(User)) 
+        // PHI nodes may have multiple incoming edges from the same BB (why??), 
+        // all must be updated at once with the same incoming value. 
+        PHI->setIncomingValueForBlock(PHI->getIncomingBlock(U), Replacement); 
+      else 
+        U.set(Replacement); 
+    } 
+ 
+    AI->eraseFromParent(); 
+  } 
+ 
+  // Re-align BasePointer so that our callees would see it aligned as 
+  // expected. 
+  // FIXME: no need to update BasePointer in leaf functions. 
+  unsigned FrameSize = alignTo(SSL.getFrameSize(), StackAlignment); 
+ 
+  // Update shadow stack pointer in the function epilogue. 
+  IRB.SetInsertPoint(BasePointer->getNextNode()); 
+ 
+  Value *StaticTop = 
+      IRB.CreateGEP(Int8Ty, BasePointer, ConstantInt::get(Int32Ty, -FrameSize), 
+                    "unsafe_stack_static_top"); 
+  IRB.CreateStore(StaticTop, UnsafeStackPtr); 
+  return StaticTop; 
+} 
+ 
+void SafeStack::moveDynamicAllocasToUnsafeStack( 
+    Function &F, Value *UnsafeStackPtr, AllocaInst *DynamicTop, 
+    ArrayRef<AllocaInst *> DynamicAllocas) { 
+  DIBuilder DIB(*F.getParent()); 
+ 
+  for (AllocaInst *AI : DynamicAllocas) { 
+    IRBuilder<> IRB(AI); 
+ 
+    // Compute the new SP value (after AI). 
+    Value *ArraySize = AI->getArraySize(); 
+    if (ArraySize->getType() != IntPtrTy) 
+      ArraySize = IRB.CreateIntCast(ArraySize, IntPtrTy, false); 
+ 
+    Type *Ty = AI->getAllocatedType(); 
+    uint64_t TySize = DL.getTypeAllocSize(Ty); 
+    Value *Size = IRB.CreateMul(ArraySize, ConstantInt::get(IntPtrTy, TySize)); 
+ 
+    Value *SP = IRB.CreatePtrToInt(IRB.CreateLoad(StackPtrTy, UnsafeStackPtr), 
+                                   IntPtrTy); 
+    SP = IRB.CreateSub(SP, Size); 
+ 
+    // Align the SP value to satisfy the AllocaInst, type and stack alignments. 
+    unsigned Align = std::max( 
+        std::max((unsigned)DL.getPrefTypeAlignment(Ty), AI->getAlignment()), 
+        (unsigned)StackAlignment); 
+ 
+    assert(isPowerOf2_32(Align)); 
+    Value *NewTop = IRB.CreateIntToPtr( 
+        IRB.CreateAnd(SP, ConstantInt::get(IntPtrTy, ~uint64_t(Align - 1))), 
+        StackPtrTy); 
+ 
+    // Save the stack pointer. 
+    IRB.CreateStore(NewTop, UnsafeStackPtr); 
+    if (DynamicTop) 
+      IRB.CreateStore(NewTop, DynamicTop); 
+ 
+    Value *NewAI = IRB.CreatePointerCast(NewTop, AI->getType()); 
+    if (AI->hasName() && isa<Instruction>(NewAI)) 
+      NewAI->takeName(AI); 
+ 
+    replaceDbgDeclare(AI, NewAI, DIB, DIExpression::ApplyOffset, 0); 
+    AI->replaceAllUsesWith(NewAI); 
+    AI->eraseFromParent(); 
+  } 
+ 
+  if (!DynamicAllocas.empty()) { 
+    // Now go through the instructions again, replacing stacksave/stackrestore. 
+    for (inst_iterator It = inst_begin(&F), Ie = inst_end(&F); It != Ie;) { 
+      Instruction *I = &*(It++); 
+      auto II = dyn_cast<IntrinsicInst>(I); 
+      if (!II) 
+        continue; 
+ 
+      if (II->getIntrinsicID() == Intrinsic::stacksave) { 
+        IRBuilder<> IRB(II); 
+        Instruction *LI = IRB.CreateLoad(StackPtrTy, UnsafeStackPtr); 
+        LI->takeName(II); 
+        II->replaceAllUsesWith(LI); 
+        II->eraseFromParent(); 
+      } else if (II->getIntrinsicID() == Intrinsic::stackrestore) { 
+        IRBuilder<> IRB(II); 
+        Instruction *SI = IRB.CreateStore(II->getArgOperand(0), UnsafeStackPtr); 
+        SI->takeName(II); 
+        assert(II->use_empty()); 
+        II->eraseFromParent(); 
+      } 
+    } 
+  } 
+} 
+ 
+bool SafeStack::ShouldInlinePointerAddress(CallInst &CI) { 
+  Function *Callee = CI.getCalledFunction(); 
+  if (CI.hasFnAttr(Attribute::AlwaysInline) && 
+      isInlineViable(*Callee).isSuccess()) 
+    return true; 
+  if (Callee->isInterposable() || Callee->hasFnAttribute(Attribute::NoInline) || 
+      CI.isNoInline()) 
+    return false; 
+  return true; 
+} 
+ 
+void SafeStack::TryInlinePointerAddress() { 
+  auto *CI = dyn_cast<CallInst>(UnsafeStackPtr); 
+  if (!CI) 
+    return; 
+ 
+  if(F.hasOptNone()) 
+    return; 
+ 
+  Function *Callee = CI->getCalledFunction(); 
+  if (!Callee || Callee->isDeclaration()) 
+    return; 
+ 
+  if (!ShouldInlinePointerAddress(*CI)) 
+    return; 
+ 
+  InlineFunctionInfo IFI; 
+  InlineFunction(*CI, IFI); 
+} 
+ 
+bool SafeStack::run() { 
+  assert(F.hasFnAttribute(Attribute::SafeStack) && 
+         "Can't run SafeStack on a function without the attribute"); 
+  assert(!F.isDeclaration() && "Can't run SafeStack on a function declaration"); 
+ 
+  ++NumFunctions; 
+ 
+  SmallVector<AllocaInst *, 16> StaticAllocas; 
+  SmallVector<AllocaInst *, 4> DynamicAllocas; 
+  SmallVector<Argument *, 4> ByValArguments; 
   SmallVector<Instruction *, 4> Returns;
-
-  // Collect all points where stack gets unwound and needs to be restored
-  // This is only necessary because the runtime (setjmp and unwind code) is
-  // not aware of the unsafe stack and won't unwind/restore it properly.
-  // To work around this problem without changing the runtime, we insert
-  // instrumentation to restore the unsafe stack pointer when necessary.
-  SmallVector<Instruction *, 4> StackRestorePoints;
-
-  // Find all static and dynamic alloca instructions that must be moved to the
-  // unsafe stack, all return instructions and stack restore points.
-  findInsts(F, StaticAllocas, DynamicAllocas, ByValArguments, Returns,
-            StackRestorePoints);
-
-  if (StaticAllocas.empty() && DynamicAllocas.empty() &&
-      ByValArguments.empty() && StackRestorePoints.empty())
-    return false; // Nothing to do in this function.
-
-  if (!StaticAllocas.empty() || !DynamicAllocas.empty() ||
-      !ByValArguments.empty())
-    ++NumUnsafeStackFunctions; // This function has the unsafe stack.
-
-  if (!StackRestorePoints.empty())
-    ++NumUnsafeStackRestorePointsFunctions;
-
-  IRBuilder<> IRB(&F.front(), F.begin()->getFirstInsertionPt());
-  // Calls must always have a debug location, or else inlining breaks. So
-  // we explicitly set a artificial debug location here.
-  if (DISubprogram *SP = F.getSubprogram())
+ 
+  // Collect all points where stack gets unwound and needs to be restored 
+  // This is only necessary because the runtime (setjmp and unwind code) is 
+  // not aware of the unsafe stack and won't unwind/restore it properly. 
+  // To work around this problem without changing the runtime, we insert 
+  // instrumentation to restore the unsafe stack pointer when necessary. 
+  SmallVector<Instruction *, 4> StackRestorePoints; 
+ 
+  // Find all static and dynamic alloca instructions that must be moved to the 
+  // unsafe stack, all return instructions and stack restore points. 
+  findInsts(F, StaticAllocas, DynamicAllocas, ByValArguments, Returns, 
+            StackRestorePoints); 
+ 
+  if (StaticAllocas.empty() && DynamicAllocas.empty() && 
+      ByValArguments.empty() && StackRestorePoints.empty()) 
+    return false; // Nothing to do in this function. 
+ 
+  if (!StaticAllocas.empty() || !DynamicAllocas.empty() || 
+      !ByValArguments.empty()) 
+    ++NumUnsafeStackFunctions; // This function has the unsafe stack. 
+ 
+  if (!StackRestorePoints.empty()) 
+    ++NumUnsafeStackRestorePointsFunctions; 
+ 
+  IRBuilder<> IRB(&F.front(), F.begin()->getFirstInsertionPt()); 
+  // Calls must always have a debug location, or else inlining breaks. So 
+  // we explicitly set a artificial debug location here. 
+  if (DISubprogram *SP = F.getSubprogram()) 
     IRB.SetCurrentDebugLocation(
         DILocation::get(SP->getContext(), SP->getScopeLine(), 0, SP));
-  if (SafeStackUsePointerAddress) {
-    FunctionCallee Fn = F.getParent()->getOrInsertFunction(
-        "__safestack_pointer_address", StackPtrTy->getPointerTo(0));
-    UnsafeStackPtr = IRB.CreateCall(Fn);
-  } else {
-    UnsafeStackPtr = TL.getSafeStackPointerLocation(IRB);
-  }
-
-  // Load the current stack pointer (we'll also use it as a base pointer).
-  // FIXME: use a dedicated register for it ?
-  Instruction *BasePointer =
-      IRB.CreateLoad(StackPtrTy, UnsafeStackPtr, false, "unsafe_stack_ptr");
-  assert(BasePointer->getType() == StackPtrTy);
-
-  AllocaInst *StackGuardSlot = nullptr;
-  // FIXME: implement weaker forms of stack protector.
-  if (F.hasFnAttribute(Attribute::StackProtect) ||
-      F.hasFnAttribute(Attribute::StackProtectStrong) ||
-      F.hasFnAttribute(Attribute::StackProtectReq)) {
-    Value *StackGuard = getStackGuard(IRB, F);
-    StackGuardSlot = IRB.CreateAlloca(StackPtrTy, nullptr);
-    IRB.CreateStore(StackGuard, StackGuardSlot);
-
+  if (SafeStackUsePointerAddress) { 
+    FunctionCallee Fn = F.getParent()->getOrInsertFunction( 
+        "__safestack_pointer_address", StackPtrTy->getPointerTo(0)); 
+    UnsafeStackPtr = IRB.CreateCall(Fn); 
+  } else { 
+    UnsafeStackPtr = TL.getSafeStackPointerLocation(IRB); 
+  } 
+ 
+  // Load the current stack pointer (we'll also use it as a base pointer). 
+  // FIXME: use a dedicated register for it ? 
+  Instruction *BasePointer = 
+      IRB.CreateLoad(StackPtrTy, UnsafeStackPtr, false, "unsafe_stack_ptr"); 
+  assert(BasePointer->getType() == StackPtrTy); 
+ 
+  AllocaInst *StackGuardSlot = nullptr; 
+  // FIXME: implement weaker forms of stack protector. 
+  if (F.hasFnAttribute(Attribute::StackProtect) || 
+      F.hasFnAttribute(Attribute::StackProtectStrong) || 
+      F.hasFnAttribute(Attribute::StackProtectReq)) { 
+    Value *StackGuard = getStackGuard(IRB, F); 
+    StackGuardSlot = IRB.CreateAlloca(StackPtrTy, nullptr); 
+    IRB.CreateStore(StackGuard, StackGuardSlot); 
+ 
     for (Instruction *RI : Returns) {
-      IRBuilder<> IRBRet(RI);
-      checkStackGuard(IRBRet, F, *RI, StackGuardSlot, StackGuard);
-    }
-  }
-
-  // The top of the unsafe stack after all unsafe static allocas are
-  // allocated.
+      IRBuilder<> IRBRet(RI); 
+      checkStackGuard(IRBRet, F, *RI, StackGuardSlot, StackGuard); 
+    } 
+  } 
+ 
+  // The top of the unsafe stack after all unsafe static allocas are 
+  // allocated. 
   Value *StaticTop = moveStaticAllocasToUnsafeStack(
       IRB, F, StaticAllocas, ByValArguments, BasePointer, StackGuardSlot);
-
-  // Safe stack object that stores the current unsafe stack top. It is updated
-  // as unsafe dynamic (non-constant-sized) allocas are allocated and freed.
-  // This is only needed if we need to restore stack pointer after longjmp
-  // or exceptions, and we have dynamic allocations.
-  // FIXME: a better alternative might be to store the unsafe stack pointer
-  // before setjmp / invoke instructions.
-  AllocaInst *DynamicTop = createStackRestorePoints(
-      IRB, F, StackRestorePoints, StaticTop, !DynamicAllocas.empty());
-
-  // Handle dynamic allocas.
-  moveDynamicAllocasToUnsafeStack(F, UnsafeStackPtr, DynamicTop,
-                                  DynamicAllocas);
-
-  // Restore the unsafe stack pointer before each return.
+ 
+  // Safe stack object that stores the current unsafe stack top. It is updated 
+  // as unsafe dynamic (non-constant-sized) allocas are allocated and freed. 
+  // This is only needed if we need to restore stack pointer after longjmp 
+  // or exceptions, and we have dynamic allocations. 
+  // FIXME: a better alternative might be to store the unsafe stack pointer 
+  // before setjmp / invoke instructions. 
+  AllocaInst *DynamicTop = createStackRestorePoints( 
+      IRB, F, StackRestorePoints, StaticTop, !DynamicAllocas.empty()); 
+ 
+  // Handle dynamic allocas. 
+  moveDynamicAllocasToUnsafeStack(F, UnsafeStackPtr, DynamicTop, 
+                                  DynamicAllocas); 
+ 
+  // Restore the unsafe stack pointer before each return. 
   for (Instruction *RI : Returns) {
-    IRB.SetInsertPoint(RI);
-    IRB.CreateStore(BasePointer, UnsafeStackPtr);
-  }
-
-  TryInlinePointerAddress();
-
-  LLVM_DEBUG(dbgs() << "[SafeStack]     safestack applied\n");
-  return true;
-}
-
-class SafeStackLegacyPass : public FunctionPass {
-  const TargetMachine *TM = nullptr;
-
-public:
-  static char ID; // Pass identification, replacement for typeid..
-
-  SafeStackLegacyPass() : FunctionPass(ID) {
-    initializeSafeStackLegacyPassPass(*PassRegistry::getPassRegistry());
-  }
-
-  void getAnalysisUsage(AnalysisUsage &AU) const override {
-    AU.addRequired<TargetPassConfig>();
-    AU.addRequired<TargetLibraryInfoWrapperPass>();
-    AU.addRequired<AssumptionCacheTracker>();
-  }
-
-  bool runOnFunction(Function &F) override {
-    LLVM_DEBUG(dbgs() << "[SafeStack] Function: " << F.getName() << "\n");
-
-    if (!F.hasFnAttribute(Attribute::SafeStack)) {
-      LLVM_DEBUG(dbgs() << "[SafeStack]     safestack is not requested"
-                           " for this function\n");
-      return false;
-    }
-
-    if (F.isDeclaration()) {
-      LLVM_DEBUG(dbgs() << "[SafeStack]     function definition"
-                           " is not available\n");
-      return false;
-    }
-
-    TM = &getAnalysis<TargetPassConfig>().getTM<TargetMachine>();
-    auto *TL = TM->getSubtargetImpl(F)->getTargetLowering();
-    if (!TL)
-      report_fatal_error("TargetLowering instance is required");
-
-    auto *DL = &F.getParent()->getDataLayout();
-    auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
-    auto &ACT = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
-
-    // Compute DT and LI only for functions that have the attribute.
-    // This is only useful because the legacy pass manager doesn't let us
-    // compute analyzes lazily.
-    // In the backend pipeline, nothing preserves DT before SafeStack, so we
-    // would otherwise always compute it wastefully, even if there is no
-    // function with the safestack attribute.
-    DominatorTree DT(F);
-    LoopInfo LI(DT);
-
-    ScalarEvolution SE(F, TLI, ACT, DT, LI);
-
-    return SafeStack(F, *TL, *DL, SE).run();
-  }
-};
-
-} // end anonymous namespace
-
-char SafeStackLegacyPass::ID = 0;
-
-INITIALIZE_PASS_BEGIN(SafeStackLegacyPass, DEBUG_TYPE,
-                      "Safe Stack instrumentation pass", false, false)
-INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
-INITIALIZE_PASS_END(SafeStackLegacyPass, DEBUG_TYPE,
-                    "Safe Stack instrumentation pass", false, false)
-
-FunctionPass *llvm::createSafeStackPass() { return new SafeStackLegacyPass(); }
+    IRB.SetInsertPoint(RI); 
+    IRB.CreateStore(BasePointer, UnsafeStackPtr); 
+  } 
+ 
+  TryInlinePointerAddress(); 
+ 
+  LLVM_DEBUG(dbgs() << "[SafeStack]     safestack applied\n"); 
+  return true; 
+} 
+ 
+class SafeStackLegacyPass : public FunctionPass { 
+  const TargetMachine *TM = nullptr; 
+ 
+public: 
+  static char ID; // Pass identification, replacement for typeid.. 
+ 
+  SafeStackLegacyPass() : FunctionPass(ID) { 
+    initializeSafeStackLegacyPassPass(*PassRegistry::getPassRegistry()); 
+  } 
+ 
+  void getAnalysisUsage(AnalysisUsage &AU) const override { 
+    AU.addRequired<TargetPassConfig>(); 
+    AU.addRequired<TargetLibraryInfoWrapperPass>(); 
+    AU.addRequired<AssumptionCacheTracker>(); 
+  } 
+ 
+  bool runOnFunction(Function &F) override { 
+    LLVM_DEBUG(dbgs() << "[SafeStack] Function: " << F.getName() << "\n"); 
+ 
+    if (!F.hasFnAttribute(Attribute::SafeStack)) { 
+      LLVM_DEBUG(dbgs() << "[SafeStack]     safestack is not requested" 
+                           " for this function\n"); 
+      return false; 
+    } 
+ 
+    if (F.isDeclaration()) { 
+      LLVM_DEBUG(dbgs() << "[SafeStack]     function definition" 
+                           " is not available\n"); 
+      return false; 
+    } 
+ 
+    TM = &getAnalysis<TargetPassConfig>().getTM<TargetMachine>(); 
+    auto *TL = TM->getSubtargetImpl(F)->getTargetLowering(); 
+    if (!TL) 
+      report_fatal_error("TargetLowering instance is required"); 
+ 
+    auto *DL = &F.getParent()->getDataLayout(); 
+    auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F); 
+    auto &ACT = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F); 
+ 
+    // Compute DT and LI only for functions that have the attribute. 
+    // This is only useful because the legacy pass manager doesn't let us 
+    // compute analyzes lazily. 
+    // In the backend pipeline, nothing preserves DT before SafeStack, so we 
+    // would otherwise always compute it wastefully, even if there is no 
+    // function with the safestack attribute. 
+    DominatorTree DT(F); 
+    LoopInfo LI(DT); 
+ 
+    ScalarEvolution SE(F, TLI, ACT, DT, LI); 
+ 
+    return SafeStack(F, *TL, *DL, SE).run(); 
+  } 
+}; 
+ 
+} // end anonymous namespace 
+ 
+char SafeStackLegacyPass::ID = 0; 
+ 
+INITIALIZE_PASS_BEGIN(SafeStackLegacyPass, DEBUG_TYPE, 
+                      "Safe Stack instrumentation pass", false, false) 
+INITIALIZE_PASS_DEPENDENCY(TargetPassConfig) 
+INITIALIZE_PASS_END(SafeStackLegacyPass, DEBUG_TYPE, 
+                    "Safe Stack instrumentation pass", false, false) 
+ 
+FunctionPass *llvm::createSafeStackPass() { return new SafeStackLegacyPass(); }