[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

1071

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

bool DataFlowSanitizer::runImpl(Module &M) {
 
   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, {});
+  assert(DFS.ArgTLS);
 }
 
 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, {});
+  assert(DFS.RetvalTLS);
 }
 
 Value *DFSanFunction::getArgTLS(unsigned Idx, Instruction *Pos) {
   IRBuilder<> IRB(Pos);
   return IRB.CreateConstGEP2_64(ArrayType::get(DFS.ShadowTy, 64),
                                 getArgTLSPtr(), 0, Idx);
 }