[llvm][NFC][CallSite] Remove CallSite from TypeMetadataUtils & related

[craig.topper]

llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp

356

Why the "= nullptr"?

470

Can we rename this variable while you're here? I'm not sure what CI was meant to stand for. And its shadowed by another CI inside the loop.

1281

Would Args.append(CB.arg_begin(), CB.arg_end()) work here?

[mtrofin]

feedback

llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp

356

Drive-by change. Lower chance of later maintainability issues, and it's easy and harmless to set it here (same for NumUnsafeUses)

[craig.topper]

LGTM

llvm/include/llvm/Analysis/TypeMetadataUtils.h

 // for devirtualization.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_ANALYSIS_TYPEMETADATAUTILS_H
 #define LLVM_ANALYSIS_TYPEMETADATAUTILS_H
 
 #include "llvm/ADT/SmallVector.h"
-#include "llvm/IR/CallSite.h"
+#include "llvm/IR/Instructions.h"
 
 namespace llvm {
 
 class DominatorTree;
 
 /// The type of CFI jumptable needed for a function.
 enum CfiFunctionLinkage {
   CFL_Definition = 0,
   CFL_Declaration = 1,
   CFL_WeakDeclaration = 2
 };
 
 /// A call site that could be devirtualized.
 struct DevirtCallSite {
   /// The offset from the address point to the virtual function.
   uint64_t Offset;
   /// The call site itself.
-  CallSite CS;
+  CallBase &CB;
 };
 
 /// Given a call to the intrinsic \@llvm.type.test, find all devirtualizable
 /// call sites based on the call and return them in DevirtCalls.
 void findDevirtualizableCallsForTypeTest(
     SmallVectorImpl<DevirtCallSite> &DevirtCalls,
     SmallVectorImpl<CallInst *> &Assumes, const CallInst *CI,
     DominatorTree &DT);

llvm/lib/Analysis/ModuleSummaryAnalysis.cpp

 #include "llvm/Analysis/BlockFrequencyInfo.h"
 #include "llvm/Analysis/BranchProbabilityInfo.h"
 #include "llvm/Analysis/IndirectCallPromotionAnalysis.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/ProfileSummaryInfo.h"
 #include "llvm/Analysis/TypeMetadataUtils.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/BasicBlock.h"
-#include "llvm/IR/CallSite.h"
 #include "llvm/IR/Constant.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/GlobalAlias.h"
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/IR/GlobalVariable.h"
 #include "llvm/IR/Instructions.h"
static bool findRefEdges(ModuleSummaryIndex &Index, const User *CurUser,
   Worklist.push_back(CurUser);
 
   while (!Worklist.empty()) {
     const User *U = Worklist.pop_back_val();
 
     if (!Visited.insert(U).second)
       continue;
 
-    ImmutableCallSite CS(U);
+    const auto *CB = dyn_cast<CallBase>(U);
 
     for (const auto &OI : U->operands()) {
       const User *Operand = dyn_cast<User>(OI);
       if (!Operand)
         continue;
       if (isa<BlockAddress>(Operand)) {
         HasBlockAddress = true;
         continue;
       }
       if (auto *GV = dyn_cast<GlobalValue>(Operand)) {
         // We have a reference to a global value. This should be added to
         // the reference set unless it is a callee. Callees are handled
         // specially by WriteFunction and are added to a separate list.
-        if (!(CS && CS.isCallee(&OI)))
+        if (!(CB && CB->isCallee(&OI)))
           RefEdges.insert(Index.getOrInsertValueInfo(GV));
         continue;
       }
       Worklist.push_back(Operand);
     }
   }
   return HasBlockAddress;
 }

 
 /// Determine whether this call has all constant integer arguments (excluding
 /// "this") and summarize it to VCalls or ConstVCalls as appropriate.
 static void addVCallToSet(DevirtCallSite Call, GlobalValue::GUID Guid,
                           SetVector<FunctionSummary::VFuncId> &VCalls,
                           SetVector<FunctionSummary::ConstVCall> &ConstVCalls) {
   std::vector<uint64_t> Args;
   // Start from the second argument to skip the "this" pointer.
-  for (auto &Arg : make_range(Call.CS.arg_begin() + 1, Call.CS.arg_end())) {
+  for (auto &Arg : make_range(Call.CB.arg_begin() + 1, Call.CB.arg_end())) {
     auto *CI = dyn_cast<ConstantInt>(Arg);
     if (!CI || CI->getBitWidth() > 64) {
       VCalls.insert({Guid, Call.Offset});
       return;
     }
     Args.push_back(CI->getZExtValue());
   }
   ConstVCalls.insert({{Guid, Call.Offset}, std::move(Args)});
for (const Instruction &I : BB) {
             // of calling it we should add GV to RefEdges directly.
             RefEdges.insert(Index.getOrInsertValueInfo(GV));
           else if (auto *U = dyn_cast<User>(Stored))
             findRefEdges(Index, U, RefEdges, Visited);
           continue;
         }
       }
       findRefEdges(Index, &I, RefEdges, Visited);
-      auto CS = ImmutableCallSite(&I);
-      if (!CS)
+      const auto *CB = dyn_cast<CallBase>(&I);
+      if (!CB)
         continue;
 
       const auto *CI = dyn_cast<CallInst>(&I);
       // Since we don't know exactly which local values are referenced in inline
       // assembly, conservatively mark the function as possibly referencing
       // a local value from inline assembly to ensure we don't export a
       // reference (which would require renaming and promotion of the
       // referenced value).
       if (HasLocalsInUsedOrAsm && CI && CI->isInlineAsm())
         HasInlineAsmMaybeReferencingInternal = true;
 
-      auto *CalledValue = CS.getCalledValue();
-      auto *CalledFunction = CS.getCalledFunction();
+      auto *CalledValue = CB->getCalledValue();
+      auto *CalledFunction = CB->getCalledFunction();
       if (CalledValue && !CalledFunction) {
         CalledValue = CalledValue->stripPointerCasts();
         // Stripping pointer casts can reveal a called function.
         CalledFunction = dyn_cast<Function>(CalledValue);
       }
       // Check if this is an alias to a function. If so, get the
       // called aliasee for the checks below.
       if (auto *GA = dyn_cast<GlobalAlias>(CalledValue)) {

llvm/lib/Analysis/TypeMetadataUtils.cpp

for (const Use &U : FPtr->uses()) {
     // after indirect call promotion and inlining, where we may have uses
     // of the vtable pointer guarded by a function pointer check, and a fallback
     // indirect call.
     if (!DT.dominates(CI, User))
       continue;
     if (isa<BitCastInst>(User)) {
       findCallsAtConstantOffset(DevirtCalls, HasNonCallUses, User, Offset, CI,
                                 DT);
-    } else if (auto CI = dyn_cast<CallInst>(User)) {
-      DevirtCalls.push_back({Offset, CI});
-    } else if (auto II = dyn_cast<InvokeInst>(User)) {
-      DevirtCalls.push_back({Offset, II});
+    } else if (auto *CI = dyn_cast<CallInst>(User)) {
+      DevirtCalls.push_back({Offset, *CI});
+    } else if (auto *II = dyn_cast<InvokeInst>(User)) {
+      DevirtCalls.push_back({Offset, *II});
     } else if (HasNonCallUses) {
       *HasNonCallUses = true;
     }
   }
 }
 
 // Search for virtual calls that load from VPtr and add them to DevirtCalls.
 static void findLoadCallsAtConstantOffset(

llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp

 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/BasicAliasAnalysis.h"
 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
 #include "llvm/Analysis/TypeMetadataUtils.h"
 #include "llvm/Bitcode/BitcodeReader.h"
 #include "llvm/Bitcode/BitcodeWriter.h"
-#include "llvm/IR/CallSite.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DebugLoc.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/GlobalAlias.h"
 #include "llvm/IR/GlobalVariable.h"

 
 } // end namespace llvm
 
 namespace {
 
 // A virtual call site. VTable is the loaded virtual table pointer, and CS is
 // the indirect virtual call.
 struct VirtualCallSite {
-  Value *VTable;
-  CallSite CS;
+  Value *VTable = nullptr;
+  CallBase &CB;
 
   // If non-null, this field points to the associated unsafe use count stored in
   // the DevirtModule::NumUnsafeUsesForTypeTest map below. See the description
   // of that field for details.
-  unsigned *NumUnsafeUses;
+  unsigned *NumUnsafeUses = nullptr;
 
   void
   emitRemark(const StringRef OptName, const StringRef TargetName,
              function_ref<OptimizationRemarkEmitter &(Function *)> OREGetter) {
-    Function *F = CS.getCaller();
-    DebugLoc DLoc = CS->getDebugLoc();
-    BasicBlock *Block = CS.getParent();
+    Function *F = CB.getCaller();
+    DebugLoc DLoc = CB.getDebugLoc();
+    BasicBlock *Block = CB.getParent();
 
     using namespace ore;
     OREGetter(F).emit(OptimizationRemark(DEBUG_TYPE, OptName, DLoc, Block)
                       << NV("Optimization", OptName)
                       << ": devirtualized a call to "
                       << NV("FunctionName", TargetName));
   }
 
   void replaceAndErase(
       const StringRef OptName, const StringRef TargetName, bool RemarksEnabled,
       function_ref<OptimizationRemarkEmitter &(Function *)> OREGetter,
       Value *New) {
     if (RemarksEnabled)
       emitRemark(OptName, TargetName, OREGetter);
-    CS->replaceAllUsesWith(New);
-    if (auto II = dyn_cast<InvokeInst>(CS.getInstruction())) {
-      BranchInst::Create(II->getNormalDest(), CS.getInstruction());
+    CB.replaceAllUsesWith(New);
+    if (auto *II = dyn_cast<InvokeInst>(&CB)) {
+      BranchInst::Create(II->getNormalDest(), &CB);
       II->getUnwindDest()->removePredecessor(II->getParent());
     }
-    CS->eraseFromParent();
+    CB.eraseFromParent();
     // This use is no longer unsafe.
     if (NumUnsafeUses)
       --*NumUnsafeUses;
   }
 };
 
 // Call site information collected for a specific VTableSlot and possibly a list
 // of constant integer arguments. The grouping by arguments is handled by the
struct VTableSlotInfo {
   // The set of call sites which do not have all constant integer arguments
   // (excluding "this").
   CallSiteInfo CSInfo;
 
   // The set of call sites with all constant integer arguments (excluding
   // "this"), grouped by argument list.
   std::map<std::vector<uint64_t>, CallSiteInfo> ConstCSInfo;
 
-  void addCallSite(Value *VTable, CallSite CS, unsigned *NumUnsafeUses);
+  void addCallSite(Value *VTable, CallBase &CB, unsigned *NumUnsafeUses);
 
 private:
-  CallSiteInfo &findCallSiteInfo(CallSite CS);
+  CallSiteInfo &findCallSiteInfo(CallBase &CB);
 };
 
-CallSiteInfo &VTableSlotInfo::findCallSiteInfo(CallSite CS) {
+CallSiteInfo &VTableSlotInfo::findCallSiteInfo(CallBase &CB) {
   std::vector<uint64_t> Args;
-  auto *CI = dyn_cast<IntegerType>(CS.getType());
-  if (!CI || CI->getBitWidth() > 64 || CS.arg_empty())
+  auto *CI = dyn_cast<IntegerType>(CB.getType());
+  if (!CI || CI->getBitWidth() > 64 || CB.arg_empty())
     return CSInfo;
-  for (auto &&Arg : make_range(CS.arg_begin() + 1, CS.arg_end())) {
+  for (auto &&Arg : make_range(CB.arg_begin() + 1, CB.arg_end())) {
     auto *CI = dyn_cast<ConstantInt>(Arg);
     if (!CI || CI->getBitWidth() > 64)
       return CSInfo;
     Args.push_back(CI->getZExtValue());
   }
   return ConstCSInfo[Args];
 }
 
-void VTableSlotInfo::addCallSite(Value *VTable, CallSite CS,
+void VTableSlotInfo::addCallSite(Value *VTable, CallBase &CB,
                                  unsigned *NumUnsafeUses) {
-  auto &CSI = findCallSiteInfo(CS);
+  auto &CSI = findCallSiteInfo(CB);
   CSI.AllCallSitesDevirted = false;
-  CSI.CallSites.push_back({VTable, CS, NumUnsafeUses});
+  CSI.CallSites.push_back({VTable, CB, NumUnsafeUses});
 }
 
 struct DevirtModule {
   Module &M;
   function_ref<AAResults &(Function &)> AARGetter;
   function_ref<DominatorTree &(Function &)> LookupDomTree;
 
   ModuleSummaryIndex *ExportSummary;

 
 void DevirtModule::applySingleImplDevirt(VTableSlotInfo &SlotInfo,
                                          Constant *TheFn, bool &IsExported) {
   auto Apply = [&](CallSiteInfo &CSInfo) {
     for (auto &&VCallSite : CSInfo.CallSites) {
       if (RemarksEnabled)
         VCallSite.emitRemark("single-impl",
                              TheFn->stripPointerCasts()->getName(), OREGetter);
-      VCallSite.CS.setCalledFunction(ConstantExpr::getBitCast(
-          TheFn, VCallSite.CS.getCalledValue()->getType()));
+      VCallSite.CB.setCalledOperand(ConstantExpr::getBitCast(
+          TheFn, VCallSite.CB.getCalledValue()->getType()));
       // This use is no longer unsafe.
       if (VCallSite.NumUnsafeUses)
         --*VCallSite.NumUnsafeUses;
     }
     if (CSInfo.isExported())
       IsExported = true;
     CSInfo.markDevirt();
   };

 void DevirtModule::applyICallBranchFunnel(VTableSlotInfo &SlotInfo,
                                           Constant *JT, bool &IsExported) {
   auto Apply = [&](CallSiteInfo &CSInfo) {
     if (CSInfo.isExported())
       IsExported = true;
     if (CSInfo.AllCallSitesDevirted)
       return;
     for (auto &&VCallSite : CSInfo.CallSites) {
-      CallSite CS = VCallSite.CS;
+      CallBase &CB = VCallSite.CB;
 
       // Jump tables are only profitable if the retpoline mitigation is enabled.
-      Attribute FSAttr = CS.getCaller()->getFnAttribute("target-features");
+      Attribute FSAttr = CB.getCaller()->getFnAttribute("target-features");
       if (FSAttr.hasAttribute(Attribute::None) ||
           !FSAttr.getValueAsString().contains("+retpoline"))
         continue;
 
       if (RemarksEnabled)
         VCallSite.emitRemark("branch-funnel",
                              JT->stripPointerCasts()->getName(), OREGetter);
 
       // Pass the address of the vtable in the nest register, which is r10 on
       // x86_64.
       std::vector<Type *> NewArgs;
       NewArgs.push_back(Int8PtrTy);
-      for (Type *T : CS.getFunctionType()->params())
+      for (Type *T : CB.getFunctionType()->params())
         NewArgs.push_back(T);
       FunctionType *NewFT =
-          FunctionType::get(CS.getFunctionType()->getReturnType(), NewArgs,
-                            CS.getFunctionType()->isVarArg());
+          FunctionType::get(CB.getFunctionType()->getReturnType(), NewArgs,
+                            CB.getFunctionType()->isVarArg());
       PointerType *NewFTPtr = PointerType::getUnqual(NewFT);
 
-      IRBuilder<> IRB(CS.getInstruction());
+      IRBuilder<> IRB(&CB);
       std::vector<Value *> Args;
       Args.push_back(IRB.CreateBitCast(VCallSite.VTable, Int8PtrTy));
-      for (unsigned I = 0; I != CS.getNumArgOperands(); ++I)
-        Args.push_back(CS.getArgOperand(I));
+      for (unsigned I = 0; I != CB.getNumArgOperands(); ++I)
+        Args.push_back(CB.getArgOperand(I));
 
-      CallSite NewCS;
-      if (CS.isCall())
+      CallBase *NewCS = nullptr;
+      if (isa<CallInst>(CB))
         NewCS = IRB.CreateCall(NewFT, IRB.CreateBitCast(JT, NewFTPtr), Args);
       else
-        NewCS = IRB.CreateInvoke(
-            NewFT, IRB.CreateBitCast(JT, NewFTPtr),
-            cast<InvokeInst>(CS.getInstruction())->getNormalDest(),
-            cast<InvokeInst>(CS.getInstruction())->getUnwindDest(), Args);
-      NewCS.setCallingConv(CS.getCallingConv());
+        NewCS = IRB.CreateInvoke(NewFT, IRB.CreateBitCast(JT, NewFTPtr),
+                                 cast<InvokeInst>(CB).getNormalDest(),
+                                 cast<InvokeInst>(CB).getUnwindDest(), Args);
+      NewCS->setCallingConv(CB.getCallingConv());
 
-      AttributeList Attrs = CS.getAttributes();
+      AttributeList Attrs = CB.getAttributes();
       std::vector<AttributeSet> NewArgAttrs;
       NewArgAttrs.push_back(AttributeSet::get(
           M.getContext(), ArrayRef<Attribute>{Attribute::get(
                               M.getContext(), Attribute::Nest)}));
       for (unsigned I = 0; I + 2 <  Attrs.getNumAttrSets(); ++I)
         NewArgAttrs.push_back(Attrs.getParamAttributes(I));
-      NewCS.setAttributes(
+      NewCS->setAttributes(
           AttributeList::get(M.getContext(), Attrs.getFnAttributes(),
                              Attrs.getRetAttributes(), NewArgAttrs));
 
-      CS->replaceAllUsesWith(NewCS.getInstruction());
-      CS->eraseFromParent();
+      CB.replaceAllUsesWith(NewCS);
+      CB.eraseFromParent();
 
       // This use is no longer unsafe.
       if (VCallSite.NumUnsafeUses)
         --*VCallSite.NumUnsafeUses;
     }
     // Don't mark as devirtualized because there may be callers compiled without
     // retpoline mitigation, which would mean that they are lowered to
     // llvm.type.test and therefore require an llvm.type.test resolution for the
bool DevirtModule::tryEvaluateFunctionsWithArgs(
   return true;
 }
 
 void DevirtModule::applyUniformRetValOpt(CallSiteInfo &CSInfo, StringRef FnName,
                                          uint64_t TheRetVal) {
   for (auto Call : CSInfo.CallSites)
     Call.replaceAndErase(
         "uniform-ret-val", FnName, RemarksEnabled, OREGetter,
-        ConstantInt::get(cast<IntegerType>(Call.CS.getType()), TheRetVal));
+        ConstantInt::get(cast<IntegerType>(Call.CB.getType()), TheRetVal));
   CSInfo.markDevirt();
 }
 
 bool DevirtModule::tryUniformRetValOpt(
     MutableArrayRef<VirtualCallTarget> TargetsForSlot, CallSiteInfo &CSInfo,
     WholeProgramDevirtResolution::ByArg *Res) {
   // Uniform return value optimization. If all functions return the same
   // constant, replace all calls with that constant.
else
     SetAbsRange(0, 1ull << AbsWidth);
   return C;
 }
 
 void DevirtModule::applyUniqueRetValOpt(CallSiteInfo &CSInfo, StringRef FnName,
                                         bool IsOne,
                                         Constant *UniqueMemberAddr) {
   for (auto &&Call : CSInfo.CallSites) {
-    IRBuilder<> B(Call.CS.getInstruction());
+    IRBuilder<> B(&Call.CB);
     Value *Cmp =
         B.CreateICmp(IsOne ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE, Call.VTable,
                      B.CreateBitCast(UniqueMemberAddr, Call.VTable->getType()));
-    Cmp = B.CreateZExt(Cmp, Call.CS->getType());
+    Cmp = B.CreateZExt(Cmp, Call.CB.getType());
     Call.replaceAndErase("unique-ret-val", FnName, RemarksEnabled, OREGetter,
                          Cmp);
   }
   CSInfo.markDevirt();
 }
 
 Constant *DevirtModule::getMemberAddr(const TypeMemberInfo *M) {
   Constant *C = ConstantExpr::getBitCast(M->Bits->GV, Int8PtrTy);
if (tryUniqueRetValOptFor(false))
       return true;
   }
   return false;
 }
 
 void DevirtModule::applyVirtualConstProp(CallSiteInfo &CSInfo, StringRef FnName,
                                          Constant *Byte, Constant *Bit) {
   for (auto Call : CSInfo.CallSites) {
-    auto *RetType = cast<IntegerType>(Call.CS.getType());
-    IRBuilder<> B(Call.CS.getInstruction());
+    auto *RetType = cast<IntegerType>(Call.CB.getType());
+    IRBuilder<> B(&Call.CB);
     Value *Addr =
         B.CreateGEP(Int8Ty, B.CreateBitCast(Call.VTable, Int8PtrTy), Byte);
     if (RetType->getBitWidth() == 1) {
       Value *Bits = B.CreateLoad(Int8Ty, Addr);
       Value *BitsAndBit = B.CreateAnd(Bits, Bit);
       auto IsBitSet = B.CreateICmpNE(BitsAndBit, ConstantInt::get(Int8Ty, 0));
       Call.replaceAndErase("virtual-const-prop-1-bit", FnName, RemarksEnabled,
                            OREGetter, IsBitSet);

 }
 
 void DevirtModule::scanTypeTestUsers(Function *TypeTestFunc) {
   // Find all virtual calls via a virtual table pointer %p under an assumption
   // of the form llvm.assume(llvm.type.test(%p, %md)). This indicates that %p
   // points to a member of the type identifier %md. Group calls by (type ID,
   // offset) pair (effectively the identity of the virtual function) and store
   // to CallSlots.
-  DenseSet<CallSite> SeenCallSites;
+  DenseSet<CallBase *> SeenCallSites;
   for (auto I = TypeTestFunc->use_begin(), E = TypeTestFunc->use_end();
        I != E;) {
     auto CI = dyn_cast<CallInst>(I->getUser());
     ++I;
     if (!CI)
       continue;
 
     // Search for virtual calls based on %p and add them to DevirtCalls.
     SmallVector<DevirtCallSite, 1> DevirtCalls;
     SmallVector<CallInst *, 1> Assumes;
     auto &DT = LookupDomTree(*CI->getFunction());
     findDevirtualizableCallsForTypeTest(DevirtCalls, Assumes, CI, DT);
 
     // If we found any, add them to CallSlots.
     if (!Assumes.empty()) {
       Metadata *TypeId =
           cast<MetadataAsValue>(CI->getArgOperand(1))->getMetadata();
       Value *Ptr = CI->getArgOperand(0)->stripPointerCasts();
       for (DevirtCallSite Call : DevirtCalls) {
         // Only add this CallSite if we haven't seen it before. The vtable
         // pointer may have been CSE'd with pointers from other call sites,
         // and we don't want to process call sites multiple times. We can't
         // just skip the vtable Ptr if it has been seen before, however, since
         // it may be shared by type tests that dominate different calls.
-        if (SeenCallSites.insert(Call.CS).second)
-          CallSlots[{TypeId, Call.Offset}].addCallSite(Ptr, Call.CS, nullptr);
+        if (SeenCallSites.insert(&Call.CB).second)
+          CallSlots[{TypeId, Call.Offset}].addCallSite(Ptr, Call.CB, nullptr);
       }
     }
 
     // We no longer need the assumes or the type test.
     for (auto Assume : Assumes)
       Assume->eraseFromParent();
     // We can't use RecursivelyDeleteTriviallyDeadInstructions here because we
     // may use the vtable argument later.
for (auto I = TypeCheckedLoadFunc->use_begin(),
     NumUnsafeUses = DevirtCalls.size();
 
     // If the function pointer has a non-call user, we cannot eliminate the type
     // check, as one of those users may eventually call the pointer. Increment
     // the unsafe use count to make sure it cannot reach zero.
     if (HasNonCallUses)
       ++NumUnsafeUses;
     for (DevirtCallSite Call : DevirtCalls) {
-      CallSlots[{TypeId, Call.Offset}].addCallSite(Ptr, Call.CS,
+      CallSlots[{TypeId, Call.Offset}].addCallSite(Ptr, Call.CB,
                                                    &NumUnsafeUses);
     }
 
     CI->eraseFromParent();
   }
 }
 
 void DevirtModule::importResolution(VTableSlot Slot, VTableSlotInfo &SlotInfo) {