[dfsan] Remove deadcode from DFSanFunction::get*TLS*()

[stephan.yichao.zhao]

Summary

clean more deadcode after D84704

[stephan.yichao.zhao]

update

[morehouse]

llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp

1054

Since these functions are now just assigning and returning variables, can we completely remove the functions and the *TLSPtr variables, and just use DFS.*TLS directly?

[stephan.yichao.zhao]

addressed comments

[GMNGeoffrey]

FYI this results in unused private fields which causes diagnostic errors for -Wunused-private-field.

llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp:365:13: error: private field 'GetArgTLS' is not used [-Werror,-Wunused-private-field]
  Constant *GetArgTLS;
            ^
llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp:366:13: error: private field 'GetRetvalTLS' is not used [-Werror,-Wunused-private-field]
  Constant *GetRetvalTLS;

[GMNGeoffrey]

In D91762#2406552, @GMNGeoffrey wrote:

FYI this results in unused private fields which causes diagnostic errors for -Wunused-private-field.

llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp:365:13: error: private field 'GetArgTLS' is not used [-Werror,-Wunused-private-field]
  Constant *GetArgTLS;
            ^
llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp:366:13: error: private field 'GetRetvalTLS' is not used [-Werror,-Wunused-private-field]
  Constant *GetRetvalTLS;

Fixed in https://reviews.llvm.org/D91820/

llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp

class DataFlowSanitizer {
   IntegerType *ShadowTy;
   PointerType *ShadowPtrTy;
   IntegerType *IntptrTy;
   ConstantInt *ZeroShadow;
   ConstantInt *ShadowPtrMask;
   ConstantInt *ShadowPtrMul;
   Constant *ArgTLS;
   Constant *RetvalTLS;
-  FunctionType *GetArgTLSTy;
-  FunctionType *GetRetvalTLSTy;
   Constant *GetArgTLS;
   Constant *GetRetvalTLS;
   Constant *ExternalShadowMask;
   FunctionType *DFSanUnionFnTy;
   FunctionType *DFSanUnionLoadFnTy;
   FunctionType *DFSanUnimplementedFnTy;
   FunctionType *DFSanSetLabelFnTy;
   FunctionType *DFSanNonzeroLabelFnTy;

 };
 
 struct DFSanFunction {
   DataFlowSanitizer &DFS;
   Function *F;
   DominatorTree DT;
   DataFlowSanitizer::InstrumentedABI IA;
   bool IsNativeABI;
-  Value *ArgTLSPtr = nullptr;
-  Value *RetvalTLSPtr = nullptr;
   AllocaInst *LabelReturnAlloca = nullptr;
   DenseMap<Value *, Value *> ValShadowMap;
   DenseMap<AllocaInst *, AllocaInst *> AllocaShadowMap;
   std::vector<std::pair<PHINode *, PHINode *>> PHIFixups;
   DenseSet<Instruction *> SkipInsts;
   std::vector<Value *> NonZeroChecks;
   bool AvoidNewBlocks;
 
   struct CachedCombinedShadow {
     BasicBlock *Block;
     Value *Shadow;
   };
   DenseMap<std::pair<Value *, Value *>, CachedCombinedShadow>
       CachedCombinedShadows;
   DenseMap<Value *, std::set<Value *>> ShadowElements;
 
   DFSanFunction(DataFlowSanitizer &DFS, Function *F, bool IsNativeABI)
       : DFS(DFS), F(F), IA(DFS.getInstrumentedABI()), IsNativeABI(IsNativeABI) {
     DT.recalculate(*F);
     // FIXME: Need to track down the register allocator issue which causes poor
     // performance in pathological cases with large numbers of basic blocks.
     AvoidNewBlocks = F->size() > 1000;
   }
 
-  Value *getArgTLSPtr();
   Value *getArgTLS(unsigned Index, Instruction *Pos);
-  Value *getRetvalTLS();
   Value *getShadow(Value *V);
   void setShadow(Instruction *I, Value *Shadow);
   Value *combineShadows(Value *V1, Value *V2, Instruction *Pos);
   Value *combineOperandShadows(Instruction *Inst);
   Value *loadShadow(Value *ShadowAddr, uint64_t Size, uint64_t Align,
                     Instruction *Pos);
   void storeShadow(Value *Addr, uint64_t Size, Align Alignment, Value *Shadow,
                    Instruction *Pos);
if (ClDebugNonzeroLabels) {
       }
     }
   }
 
   return Changed || !FnsToInstrument.empty() ||
          M.global_size() != InitialGlobalSize || M.size() != InitialModuleSize;
 }
 
-Value *DFSanFunction::getArgTLSPtr() {
-  if (ArgTLSPtr)
-    return ArgTLSPtr;
-  if (DFS.ArgTLS)
-    return ArgTLSPtr = DFS.ArgTLS;
-
-  IRBuilder<> IRB(&F->getEntryBlock().front());
-  return ArgTLSPtr = IRB.CreateCall(DFS.GetArgTLSTy, DFS.GetArgTLS, {});
-}
-
-Value *DFSanFunction::getRetvalTLS() {
-  if (RetvalTLSPtr)
-    return RetvalTLSPtr;
-  if (DFS.RetvalTLS)
-    return RetvalTLSPtr = DFS.RetvalTLS;
-
-  IRBuilder<> IRB(&F->getEntryBlock().front());
-  return RetvalTLSPtr =
-             IRB.CreateCall(DFS.GetRetvalTLSTy, DFS.GetRetvalTLS, {});
-}
-
 Value *DFSanFunction::getArgTLS(unsigned Idx, Instruction *Pos) {
   IRBuilder<> IRB(Pos);
-  return IRB.CreateConstGEP2_64(ArrayType::get(DFS.ShadowTy, 64),
-                                getArgTLSPtr(), 0, Idx);
+  return IRB.CreateConstGEP2_64(ArrayType::get(DFS.ShadowTy, 64), DFS.ArgTLS, 0,
+                                Idx);
 }
 
 Value *DFSanFunction::getShadow(Value *V) {
   if (!isa<Argument>(V) && !isa<Instruction>(V))
     return DFS.ZeroShadow;
   Value *&Shadow = ValShadowMap[V];
   if (!Shadow) {
     if (Argument *A = dyn_cast<Argument>(V)) {
       if (IsNativeABI)
         return DFS.ZeroShadow;
       switch (IA) {
       case DataFlowSanitizer::IA_TLS: {
-        Value *ArgTLSPtr = getArgTLSPtr();
+        Value *ArgTLSPtr = DFS.ArgTLS;
         Instruction *ArgTLSPos =
             DFS.ArgTLS ? &*F->getEntryBlock().begin()
                        : cast<Instruction>(ArgTLSPtr)->getNextNode();
         IRBuilder<> IRB(ArgTLSPos);
         Shadow =
             IRB.CreateLoad(DFS.ShadowTy, getArgTLS(A->getArgNo(), ArgTLSPos));
         break;
       }

 }
 
 void DFSanVisitor::visitReturnInst(ReturnInst &RI) {
   if (!DFSF.IsNativeABI && RI.getReturnValue()) {
     switch (DFSF.IA) {
     case DataFlowSanitizer::IA_TLS: {
       Value *S = DFSF.getShadow(RI.getReturnValue());
       IRBuilder<> IRB(&RI);
-      IRB.CreateStore(S, DFSF.getRetvalTLS());
+      IRB.CreateStore(S, DFSF.DFS.RetvalTLS);
       break;
     }
     case DataFlowSanitizer::IA_Args: {
       IRBuilder<> IRB(&RI);
       Type *RT = DFSF.F->getFunctionType()->getReturnType();
       Value *InsVal =
           IRB.CreateInsertValue(UndefValue::get(RT), RI.getReturnValue(), 0);
       Value *InsShadow =
if (InvokeInst *II = dyn_cast<InvokeInst>(&CB)) {
       }
     } else {
       assert(CB.getIterator() != CB.getParent()->end());
       Next = CB.getNextNode();
     }
 
     if (DFSF.DFS.getInstrumentedABI() == DataFlowSanitizer::IA_TLS) {
       IRBuilder<> NextIRB(Next);
-      LoadInst *LI = NextIRB.CreateLoad(DFSF.DFS.ShadowTy, DFSF.getRetvalTLS());
+      LoadInst *LI = NextIRB.CreateLoad(DFSF.DFS.ShadowTy, DFSF.DFS.RetvalTLS);
       DFSF.SkipInsts.insert(LI);
       DFSF.setShadow(&CB, LI);
       DFSF.NonZeroChecks.push_back(LI);
     }
   }
 
   // Do all instrumentation for IA_Args down here to defer tampering with the
   // CFG in a way that SplitEdge may be able to detect.