CodeGen: Remove pipeline dependencies on StackProtector; NFC

[rinon]

Summary

PrologEpilogInserter and StackColoring depend on the StackProtector analysis
being alive from the point it is run until PEI, which requires that they are all
scheduled in the same FunctionPassManager. Inserting a (machine) ModulePass
between StackProtector and PEI results in these passes being in separate
FunctionPassManagers and the StackProtector is not available for PEI.

PEI and StackColoring don't use much information from the StackProtector pass,
so transfering the required information to MachineFrameInfo is cleaner than
keeping the StackProtector pass around. This commit moves the SSP layout
information to MFI instead of keeping it in the pass.

This patch set (D37580, D37581, D37582, D37583, D37584, D37585, D37586, D37587)
is a first draft of the pagerando implementation described in
http://lists.llvm.org/pipermail/llvm-dev/2017-June/113794.html.

[rinon]

This patch set (D37580, D37581, D37582, D37583, D37584, D37585, D37586, D37587) is a first draft of the pagerando implementation described in http://lists.llvm.org/pipermail/llvm-dev/2017-June/113794.html.

[rinon]

Rebase

[peter.smith]

include/llvm/CodeGen/MachineFrameInfo.h

515

typo "layou" should be "layout"?

[rinon]

Fix typo

[rinon]

Rebase

[rinon]

Rebase

[MatzeB]

Ah nice, thanks for cleaning this up!
LGTM with nitpicks addressed:

• Add a "CodeGen: " prefix and a "; NFC" suffix to the commit title.

include/llvm/CodeGen/MachineFrameInfo.h

91

Don't repeat the enum name.

[MatzeB]

include/llvm/CodeGen/StackProtector.h

53

Maybe split this into a separate commit before pushing.

[rinon]

• Don't repeat enum name.
• Remove adjustForColoring since it is now unused.

[rinon]

include/llvm/CodeGen/StackProtector.h

53

I believe this needs to stay atomic with the rest of the changeset to avoid a bug between the changes. StackColoring used to call adjustForColoring() which would cause the StackProtector pass to update its mapping in the SSPLayoutMap before StackColoring RAUWed the old Alloca with a BitCast. This update is now done in the MFI without changing the StackProtector mapping. Without the change to this data type, the RAUW breaks the SSPLayoutMap since it can no longer refer to the replaced Alloca.

[MatzeB]

include/llvm/CodeGen/StackProtector.h

53

Makes sense.

[rinon]

Rebase

[rinon]

Rebase

[MatzeB]

(this patch is still good to go/accepted)

[rinon]

Rebase onto master, rather than other pagerando commits. Should fix arc patch
not being able to apply the patch.

[rinon]

Thanks. I don't have commit access, so if anyone would commit it on my behalf I'd appreciate it. Sorry, I should have mentioned this earlier.

[thegameg]

Thanks @rinon for this. Are you still interested in committing this? I would like to get this in to fix some X86 machine verifier issues.
Some comments below, other than that it LGTM, I can commit this for you after that.

include/llvm/CodeGen/StackProtector.h

41

This is now duplicated in MachineFrameInfo.h.

71

Is this still needed now that all the info is in MFI?

[MatzeB]

Sorry this fell to the cracks. I tried comitting it yesterday, but it needs some adaptation for GlobalISel now. I'm currently making some simple changes for that and will then commit...

[rinon]

In D37582#1160045, @thegameg wrote:

Thanks @rinon for this. Are you still interested in committing this? I would like to get this in to fix some X86 machine verifier issues.

Yep! I'll rebase and take a look at your MFI comments now, unless @MatzeB is already doing that.

[MatzeB]

In D37582#1160356, @rinon wrote:

In D37582#1160045, @thegameg wrote:

Thanks @rinon for this. Are you still interested in committing this? I would like to get this in to fix some X86 machine verifier issues.

Yep! I'll rebase and take a look at your MFI comments now, unless @MatzeB is already doing that.

I already have it rebased and slightly cleaned up. Just investigating a few GlobalISel failures now (GlobalISel probably wasn't enabled by default when this patch was created).

[rinon]

Thanks @MatzeB. Yes, I believe GlobalISel wasn't enabled yet when I last touched this patch. I'd be happy to take a look at those failures now, if you want.

include/llvm/CodeGen/StackProtector.h

41

Good point, this should probably use the MFI enum.

71

Yes. initializeStackProtectorMap uses getSSPLayout which uses this map. It can be dropped when we are done with the analysis pass now, though.

[MatzeB]

Put an updated version of the patch here: https://reviews.llvm.org/D49256

[rinon]

Closing this review in favor of updated version @ D49256.

include/llvm/CodeGen/MachineFrameInfo.h

 ///
 /// When prolog/epilog code emission is performed, the final stack frame is
 /// built and the machine instructions are modified to refer to the actual
 /// stack offsets of the object, eliminating all MO_FrameIndex operands from
 /// the program.
 ///
 /// @brief Abstract Stack Frame Information
 class MachineFrameInfo {
+public:
+  /// SSPLayoutKind.  Stack Smashing Protection (SSP) rules require that
+  /// vulnerable stack allocations are located close the stack protector.
+  enum SSPLayoutKind {
+    SSPLK_None,       ///< Did not trigger a stack protector.  No effect on data
+                      ///< layout.
+    SSPLK_LargeArray, ///< Array or nested array >= SSP-buffer-size.  Closest
+                      ///< to the stack protector.
+    SSPLK_SmallArray, ///< Array or nested array < SSP-buffer-size. 2nd closest
+                      ///< to the stack protector.
+    SSPLK_AddrOf      ///< The address of this allocation is exposed and
+                      ///< triggered protection.  3rd closest to the protector.
+  };
 
+private:
   // Represent a single object allocated on the stack.
   struct StackObject {
     // The offset of this object from the stack pointer on entry to
     // the function.  This field has no meaning for a variable sized element.
     int64_t SPOffset;
 
     // The size of this object on the stack. 0 means a variable sized object,
     // ~0ULL means a dead object.
struct StackObject {
     bool isAliased;
 
     /// If true, the object has been zero-extended.
     bool isZExt;
 
     /// If true, the object has been zero-extended.
     bool isSExt;
 
+    MachineFrameInfo::SSPLayoutKind SSPLayout;
+
     StackObject(uint64_t Sz, unsigned Al, int64_t SP, bool IM,
                 bool isSS, const AllocaInst *Val, bool Aliased, uint8_t ID = 0)
       : SPOffset(SP), Size(Sz), Alignment(Al), isImmutable(IM),
         isSpillSlot(isSS), isStatepointSpillSlot(false), StackID(ID),
         Alloca(Val),
-        PreAllocated(false), isAliased(Aliased), isZExt(false), isSExt(false) {}
+        PreAllocated(false), isAliased(Aliased), isZExt(false), isSExt(false),
+        SSPLayout(SSPLK_None) {}
   };
 
   /// The alignment of the stack.
   unsigned StackAlignment;
 
   /// Can the stack be realigned. This can be false if the target does not
   /// support stack realignment, or if the user asks us not to realign the
   /// stack. In this situation, overaligned allocas are all treated as dynamic
public:
   void setObjectOffset(int ObjectIdx, int64_t SPOffset) {
     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
            "Invalid Object Idx!");
     assert(!isDeadObjectIndex(ObjectIdx) &&
            "Setting frame offset for a dead object?");
     Objects[ObjectIdx+NumFixedObjects].SPOffset = SPOffset;
   }
 
+  SSPLayoutKind getObjectSSPLayout(int ObjectIdx) const {
+    assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
+           "Invalid Object Idx!");
+    return Objects[ObjectIdx+NumFixedObjects].SSPLayout;
+  }
+
+  void setObjectSSPLayout(int ObjectIdx, SSPLayoutKind Kind) {
+    assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
+           "Invalid Object Idx!");
+    assert(!isDeadObjectIndex(ObjectIdx) &&
+           "Setting SSP layou for a dead object?");
+    Objects[ObjectIdx+NumFixedObjects].SSPLayout = Kind;
+  }
+
   /// Return the number of bytes that must be allocated to hold
   /// all of the fixed size frame objects.  This is only valid after
   /// Prolog/Epilog code insertion has finalized the stack frame layout.
   uint64_t getStackSize() const { return StackSize; }
 
   /// Set the size of the stack.
   void setStackSize(uint64_t Size) { StackSize = Size; }
 

include/llvm/CodeGen/StackProtector.h

 class TargetLoweringBase;
 class TargetMachine;
 class Type;
 
 class StackProtector : public FunctionPass {
 public:
   /// SSPLayoutKind.  Stack Smashing Protection (SSP) rules require that
   /// vulnerable stack allocations are located close the stack protector.
   enum SSPLayoutKind {
     SSPLK_None,       ///< Did not trigger a stack protector.  No effect on data
                       ///< layout.
     SSPLK_LargeArray, ///< Array or nested array >= SSP-buffer-size.  Closest
                       ///< to the stack protector.
     SSPLK_SmallArray, ///< Array or nested array < SSP-buffer-size. 2nd closest
                       ///< to the stack protector.
     SSPLK_AddrOf      ///< The address of this allocation is exposed and
                       ///< triggered protection.  3rd closest to the protector.
   };
 
   /// A mapping of AllocaInsts to their required SSP layout.
-  using SSPLayoutMap = ValueMap<const AllocaInst *, SSPLayoutKind>;
+  using SSPLayoutMap = DenseMap<const AllocaInst *, SSPLayoutKind>;
 
 private:
   const TargetMachine *TM = nullptr;
 
   /// TLI - Keep a pointer of a TargetLowering to consult for determining
   /// target type sizes.
   const TargetLoweringBase *TLI = nullptr;
   Triple Trip;
 
   Function *F;
   Module *M;
 
   DominatorTree *DT;
 
   /// Layout - Mapping of allocations to the required SSPLayoutKind.
   /// StackProtector analysis will update this map when determining if an
   /// AllocaInst triggers a stack protector.
   SSPLayoutMap Layout;
 
   /// \brief The minimum size of buffers that will receive stack smashing
   /// protection when -fstack-protection is used.
   unsigned SSPBufferSize = 0;
 
   /// VisitedPHIs - The set of PHI nodes visited when determining
   /// if a variable's reference has been taken.  This set
   /// is maintained to ensure we don't visit the same PHI node multiple

lib/CodeGen/LocalStackSlotAllocation.cpp

public:
     static char ID; // Pass identification, replacement for typeid
     explicit LocalStackSlotPass() : MachineFunctionPass(ID) {
       initializeLocalStackSlotPassPass(*PassRegistry::getPassRegistry());
     }
     bool runOnMachineFunction(MachineFunction &MF) override;
 
     void getAnalysisUsage(AnalysisUsage &AU) const override {
       AU.setPreservesCFG();
-      AU.addRequired<StackProtector>();
       MachineFunctionPass::getAnalysisUsage(AU);
     }
 
   private:
   };
 } // end anonymous namespace
 
 char LocalStackSlotPass::ID = 0;
 char &llvm::LocalStackSlotAllocationID = LocalStackSlotPass::ID;
-INITIALIZE_PASS_BEGIN(LocalStackSlotPass, DEBUG_TYPE,
-                      "Local Stack Slot Allocation", false, false)
-INITIALIZE_PASS_DEPENDENCY(StackProtector)
-INITIALIZE_PASS_END(LocalStackSlotPass, DEBUG_TYPE,
-                    "Local Stack Slot Allocation", false, false)
+INITIALIZE_PASS(LocalStackSlotPass, DEBUG_TYPE,
 
 
 bool LocalStackSlotPass::runOnMachineFunction(MachineFunction &MF) {
   MachineFrameInfo &MFI = MF.getFrameInfo();
   const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
   unsigned LocalObjectCount = MFI.getObjectIndexEnd();
 
   // If the target doesn't want/need this pass, or if there are no locals

 void LocalStackSlotPass::calculateFrameObjectOffsets(MachineFunction &Fn) {
   // Loop over all of the stack objects, assigning sequential addresses...
   MachineFrameInfo &MFI = Fn.getFrameInfo();
   const TargetFrameLowering &TFI = *Fn.getSubtarget().getFrameLowering();
   bool StackGrowsDown =
     TFI.getStackGrowthDirection() == TargetFrameLowering::StackGrowsDown;
   int64_t Offset = 0;
   unsigned MaxAlign = 0;
-  StackProtector *SP = &getAnalysis<StackProtector>();
 
   // Make sure that the stack protector comes before the local variables on the
   // stack.
   SmallSet<int, 16> ProtectedObjs;
   if (MFI.getStackProtectorIndex() >= 0) {
     StackObjSet LargeArrayObjs;
     StackObjSet SmallArrayObjs;
     StackObjSet AddrOfObjs;
 
     AdjustStackOffset(MFI, MFI.getStackProtectorIndex(), Offset,
                       StackGrowsDown, MaxAlign);
 
     // Assign large stack objects first.
     for (unsigned i = 0, e = MFI.getObjectIndexEnd(); i != e; ++i) {
       if (MFI.isDeadObjectIndex(i))
         continue;
       if (MFI.getStackProtectorIndex() == (int)i)
         continue;
 
-      switch (SP->getSSPLayout(MFI.getObjectAllocation(i))) {
-      case StackProtector::SSPLK_None:
+      switch (MFI.getObjectSSPLayout(i)) {
+      case MachineFrameInfo::SSPLK_None:
         continue;
-      case StackProtector::SSPLK_SmallArray:
+      case MachineFrameInfo::SSPLK_SmallArray:
         SmallArrayObjs.insert(i);
         continue;
-      case StackProtector::SSPLK_AddrOf:
+      case MachineFrameInfo::SSPLK_AddrOf:
         AddrOfObjs.insert(i);
         continue;
-      case StackProtector::SSPLK_LargeArray:
+      case MachineFrameInfo::SSPLK_LargeArray:
         LargeArrayObjs.insert(i);
         continue;
       }
       llvm_unreachable("Unexpected SSPLayoutKind.");
     }
 
     AssignProtectedObjSet(LargeArrayObjs, ProtectedObjs, MFI, StackGrowsDown,
                           Offset, MaxAlign);

lib/CodeGen/PrologEpilogInserter.cpp

 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineInstr.h"
 #include "llvm/CodeGen/MachineLoopInfo.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/RegisterScavenging.h"
-#include "llvm/CodeGen/StackProtector.h"
 #include "llvm/CodeGen/WinEHFuncInfo.h"
 #include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/InlineAsm.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"

 WarnStackSize("warn-stack-size", cl::Hidden, cl::init((unsigned)-1),
               cl::desc("Warn for stack size bigger than the given"
                        " number"));
 
 INITIALIZE_PASS_BEGIN(PEI, DEBUG_TYPE, "Prologue/Epilogue Insertion", false,
                       false)
 INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
 INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
-INITIALIZE_PASS_DEPENDENCY(StackProtector)
 INITIALIZE_PASS_DEPENDENCY(MachineOptimizationRemarkEmitterPass)
 INITIALIZE_PASS_END(PEI, DEBUG_TYPE,
                     "Prologue/Epilogue Insertion & Frame Finalization", false,
                     false)
 
 MachineFunctionPass *llvm::createPrologEpilogInserterPass() {
   return new PEI();
 }
 
 STATISTIC(NumBytesStackSpace,
           "Number of bytes used for stack in all functions");
 
 void PEI::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesCFG();
   AU.addPreserved<MachineLoopInfo>();
   AU.addPreserved<MachineDominatorTree>();
-  AU.addRequired<StackProtector>();
   AU.addRequired<MachineOptimizationRemarkEmitterPass>();
   MachineFunctionPass::getAnalysisUsage(AU);
 }
 
 
 /// StackObjSet - A set of stack object indexes
 typedef SmallSetVector<int, 8> StackObjSet;
 
AssignProtectedObjSet(const StackObjSet &UnassignedObjs,
   }
 }
 
 /// calculateFrameObjectOffsets - Calculate actual frame offsets for all of the
 /// abstract stack objects.
 ///
 void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) {
   const TargetFrameLowering &TFI = *Fn.getSubtarget().getFrameLowering();
-  StackProtector *SP = &getAnalysis<StackProtector>();
 
   bool StackGrowsDown =
     TFI.getStackGrowthDirection() == TargetFrameLowering::StackGrowsDown;
 
   // Loop over all of the stack objects, assigning sequential addresses...
   MachineFrameInfo &MFI = Fn.getFrameInfo();
 
   // Start at the beginning of the local area.
for (unsigned i = 0, e = MFI.getObjectIndexEnd(); i != e; ++i) {
       if (RS && RS->isScavengingFrameIndex((int)i))
         continue;
       if (MFI.isDeadObjectIndex(i))
         continue;
       if (MFI.getStackProtectorIndex() == (int)i ||
           EHRegNodeFrameIndex == (int)i)
         continue;
 
-      switch (SP->getSSPLayout(MFI.getObjectAllocation(i))) {
-      case StackProtector::SSPLK_None:
+      switch (MFI.getObjectSSPLayout(i)) {
+      case MachineFrameInfo::SSPLK_None:
         continue;
-      case StackProtector::SSPLK_SmallArray:
+      case MachineFrameInfo::SSPLK_SmallArray:
         SmallArrayObjs.insert(i);
         continue;
-      case StackProtector::SSPLK_AddrOf:
+      case MachineFrameInfo::SSPLK_AddrOf:
         AddrOfObjs.insert(i);
         continue;
-      case StackProtector::SSPLK_LargeArray:
+      case MachineFrameInfo::SSPLK_LargeArray:
         LargeArrayObjs.insert(i);
         continue;
       }
       llvm_unreachable("Unexpected SSPLayoutKind.");
     }
 
     AssignProtectedObjSet(LargeArrayObjs, ProtectedObjs, MFI, StackGrowsDown,
                           Offset, MaxAlign, Skew);

lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

// A return in a swiferror returning function is a use.
       unsigned VReg; bool CreatedReg;
       std::tie(VReg, CreatedReg) = FuncInfo->getOrCreateSwiftErrorVRegUseAt(
           R, FuncInfo->MBB, FuncInfo->SwiftErrorArg);
       assert(CreatedReg);
     }
   }
 }
 
+static void intializeStackProtectorMap(StackProtector &SP, MachineFrameInfo &MFI) {
+  for (int i = 0, e = MFI.getObjectIndexEnd(); i != e; ++i) {
+    if (MFI.isDeadObjectIndex(i))
+      continue;
+
+    switch (SP.getSSPLayout(MFI.getObjectAllocation(i))) {
+    case StackProtector::SSPLK_None:
+      continue;
+    case StackProtector::SSPLK_SmallArray:
+      MFI.setObjectSSPLayout(i, MachineFrameInfo::SSPLK_SmallArray);
+      continue;
+    case StackProtector::SSPLK_AddrOf:
+      MFI.setObjectSSPLayout(i, MachineFrameInfo::SSPLK_AddrOf);
+      continue;
+    case StackProtector::SSPLK_LargeArray:
+      MFI.setObjectSSPLayout(i, MachineFrameInfo::SSPLK_LargeArray);
+      continue;
+    }
+    llvm_unreachable("Unexpected SSPLayoutKind.");
+  }
+}
+
 void SelectionDAGISel::SelectAllBasicBlocks(const Function &Fn) {
   FastISelFailed = false;
   // Initialize the Fast-ISel state, if needed.
   FastISel *FastIS = nullptr;
   if (TM.Options.EnableFastISel)
     FastIS = TLI->createFastISel(*FuncInfo, LibInfo);
 
   setupSwiftErrorVals(Fn, TLI, FuncInfo);
if (FastIS) {
 
         NumFastIselFailures += NumFastIselRemaining;
         break;
       }
 
       FastIS->recomputeInsertPt();
     }
 
-    if (getAnalysis<StackProtector>().shouldEmitSDCheck(*LLVMBB)) {
+    StackProtector &SP = getAnalysis<StackProtector>();
+    if (SP.shouldEmitSDCheck(*LLVMBB)) {
       bool FunctionBasedInstrumentation =
           TLI->getSSPStackGuardCheck(*Fn.getParent());
       SDB->SPDescriptor.initialize(LLVMBB, FuncInfo->MBBMap[LLVMBB],
                                    FunctionBasedInstrumentation);
+
+      intializeStackProtectorMap(SP, MF->getFrameInfo());
     }
 
     if (Begin != BI)
       ++NumDAGBlocks;
     else
       ++NumFastIselBlocks;
 
     if (Begin != BI) {

lib/CodeGen/StackColoring.cpp

 #include "llvm/CodeGen/MachineLoopInfo.h"
 #include "llvm/CodeGen/MachineMemOperand.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/PseudoSourceValue.h"
 #include "llvm/CodeGen/SelectionDAGNodes.h"
 #include "llvm/CodeGen/SlotIndexes.h"
-#include "llvm/CodeGen/StackProtector.h"
 #include "llvm/CodeGen/WinEHFuncInfo.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
class StackColoring : public MachineFunctionPass {
   /// values are either dead or `undef` and they will not be written to.
   SmallVector<std::unique_ptr<LiveInterval>, 16> Intervals;
   /// Maps slots to the points where they can become in-use.
   SmallVector<SmallVector<SlotIndex, 4>, 16> LiveStarts;
   /// VNInfo is used for the construction of LiveIntervals.
   VNInfo::Allocator VNInfoAllocator;
   /// SlotIndex analysis object.
   SlotIndexes *Indexes;
-  /// The stack protector object.
-  StackProtector *SP;
 
   /// The list of lifetime markers found. These markers are to be removed
   /// once the coloring is done.
   SmallVector<MachineInstr*, 8> Markers;
 
   /// Record the FI slots for which we have seen some sort of
   /// lifetime marker (either start or end).
   BitVector InterestingSlots;

 } // end anonymous namespace
 
 char StackColoring::ID = 0;
 char &llvm::StackColoringID = StackColoring::ID;
 
 INITIALIZE_PASS_BEGIN(StackColoring, DEBUG_TYPE,
                       "Merge disjoint stack slots", false, false)
 INITIALIZE_PASS_DEPENDENCY(SlotIndexes)
-INITIALIZE_PASS_DEPENDENCY(StackProtector)
 INITIALIZE_PASS_END(StackColoring, DEBUG_TYPE,
                     "Merge disjoint stack slots", false, false)
 
 void StackColoring::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.addRequired<SlotIndexes>();
-  AU.addRequired<StackProtector>();
   MachineFunctionPass::getAnalysisUsage(AU);
 }
 
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 LLVM_DUMP_METHOD void StackColoring::dumpBV(const char *tag,
                                             const BitVector &BV) const {
   dbgs() << tag << " : { ";
   for (unsigned I = 0, E = BV.size(); I != E; ++I)
if (From->getType() != To->getType()) {
       Cast->insertAfter(Inst);
       Inst = Cast;
     }
 
     // We keep both slots to maintain AliasAnalysis metadata later.
     MergedAllocas.insert(From);
     MergedAllocas.insert(To);
 
-    // Allow the stack protector to adjust its value map to account for the
-    // upcoming replacement.
-    SP->adjustForColoring(From, To);
+    // Transfer the stack protector layout tag, but make sure that SSPLK_AddrOf
+    // does not overwrite SSPLK_SmallArray or SSPLK_LargeArray, and make sure
+    // that SSPLK_SmallArray does not overwrite SSPLK_LargeArray.
+    if (MFI->getObjectSSPLayout(SI.second) != MachineFrameInfo::SSPLK_LargeArray &&
+        MFI->getObjectSSPLayout(SI.first) != MachineFrameInfo::SSPLK_AddrOf)
+      MFI->setObjectSSPLayout(SI.second, MFI->getObjectSSPLayout(SI.first));
 
     // The new alloca might not be valid in a llvm.dbg.declare for this
     // variable, so undef out the use to make the verifier happy.
     AllocaInst *FromAI = const_cast<AllocaInst *>(From);
     if (FromAI->isUsedByMetadata())
       ValueAsMetadata::handleRAUW(FromAI, UndefValue::get(FromAI->getType()));
     for (auto &Use : FromAI->uses()) {
       if (BitCastInst *BCI = dyn_cast<BitCastInst>(Use.get()))

 
 bool StackColoring::runOnMachineFunction(MachineFunction &Func) {
   DEBUG(dbgs() << "********** Stack Coloring **********\n"
                << "********** Function: "
                << ((const Value*)Func.getFunction())->getName() << '\n');
   MF = &Func;
   MFI = &MF->getFrameInfo();
   Indexes = &getAnalysis<SlotIndexes>();
-  SP = &getAnalysis<StackProtector>();
   BlockLiveness.clear();
   BasicBlocks.clear();
   BasicBlockNumbering.clear();
   Markers.clear();
   Intervals.clear();
   LiveStarts.clear();
   VNInfoAllocator.Reset();