[dfsan] Refactor runtime functions checking

[stephan.yichao.zhao]

Summary

This is a part of https://reviews.llvm.org/D95835.

[morehouse]

LGTM

llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp

class DataFlowSanitizer {
   FunctionCallee DFSanUnimplementedFn;
   FunctionCallee DFSanSetLabelFn;
   FunctionCallee DFSanNonzeroLabelFn;
   FunctionCallee DFSanVarargWrapperFn;
   FunctionCallee DFSanLoadCallbackFn;
   FunctionCallee DFSanStoreCallbackFn;
   FunctionCallee DFSanMemTransferCallbackFn;
   FunctionCallee DFSanCmpCallbackFn;
+  SmallPtrSet<Value *, 12> DFSanRuntimeFunctions;
   MDNode *ColdCallWeights;
   DFSanABIList ABIList;
   DenseMap<Value *, Function *> UnwrappedFnMap;
   AttrBuilder ReadOnlyNoneAttrs;
   bool DFSanRuntimeShadowMask = false;
 
   Value *getShadowAddress(Value *Addr, Instruction *Pos);
   bool isInstrumented(const Function *F);
DFSanUnimplementedFn =
     AL = AL.addParamAttribute(M.getContext(), 0, Attribute::ZExt);
     DFSanSetLabelFn =
         Mod->getOrInsertFunction("__dfsan_set_label", DFSanSetLabelFnTy, AL);
   }
   DFSanNonzeroLabelFn =
       Mod->getOrInsertFunction("__dfsan_nonzero_label", DFSanNonzeroLabelFnTy);
   DFSanVarargWrapperFn = Mod->getOrInsertFunction("__dfsan_vararg_wrapper",
                                                   DFSanVarargWrapperFnTy);
+
+  DFSanRuntimeFunctions.insert(DFSanUnionFn.getCallee()->stripPointerCasts());
+  DFSanRuntimeFunctions.insert(
+      DFSanCheckedUnionFn.getCallee()->stripPointerCasts());
+  DFSanRuntimeFunctions.insert(
+      DFSanUnionLoadFn.getCallee()->stripPointerCasts());
+  DFSanRuntimeFunctions.insert(
+      DFSanUnionLoadFast16LabelsFn.getCallee()->stripPointerCasts());
+  DFSanRuntimeFunctions.insert(
+      DFSanUnimplementedFn.getCallee()->stripPointerCasts());
+  DFSanRuntimeFunctions.insert(
+      DFSanSetLabelFn.getCallee()->stripPointerCasts());
+  DFSanRuntimeFunctions.insert(
+      DFSanNonzeroLabelFn.getCallee()->stripPointerCasts());
+  DFSanRuntimeFunctions.insert(
+      DFSanVarargWrapperFn.getCallee()->stripPointerCasts());
+  DFSanRuntimeFunctions.insert(
+      DFSanLoadCallbackFn.getCallee()->stripPointerCasts());
+  DFSanRuntimeFunctions.insert(
+      DFSanStoreCallbackFn.getCallee()->stripPointerCasts());
+  DFSanRuntimeFunctions.insert(
+      DFSanMemTransferCallbackFn.getCallee()->stripPointerCasts());
+  DFSanRuntimeFunctions.insert(
+      DFSanCmpCallbackFn.getCallee()->stripPointerCasts());
 }
 
 // Initializes event callback functions and declare them in the module
 void DataFlowSanitizer::initializeCallbackFunctions(Module &M) {
   DFSanLoadCallbackFn = Mod->getOrInsertFunction("__dfsan_load_callback",
                                                  DFSanLoadStoreCallbackFnTy);
   DFSanStoreCallbackFn = Mod->getOrInsertFunction("__dfsan_store_callback",
                                                   DFSanLoadStoreCallbackFnTy);
bool DataFlowSanitizer::runImpl(Module &M) {
   ExternalShadowMask =
       Mod->getOrInsertGlobal(kDFSanExternShadowPtrMask, IntptrTy);
 
   initializeCallbackFunctions(M);
   initializeRuntimeFunctions(M);
 
   std::vector<Function *> FnsToInstrument;
   SmallPtrSet<Function *, 2> FnsWithNativeABI;
-  for (Function &i : M) {
-    if (!i.isIntrinsic() &&
-        &i != DFSanUnionFn.getCallee()->stripPointerCasts() &&
-        &i != DFSanCheckedUnionFn.getCallee()->stripPointerCasts() &&
-        &i != DFSanUnionLoadFn.getCallee()->stripPointerCasts() &&
-        &i != DFSanUnionLoadFast16LabelsFn.getCallee()->stripPointerCasts() &&
-        &i != DFSanUnimplementedFn.getCallee()->stripPointerCasts() &&
-        &i != DFSanSetLabelFn.getCallee()->stripPointerCasts() &&
-        &i != DFSanNonzeroLabelFn.getCallee()->stripPointerCasts() &&
-        &i != DFSanVarargWrapperFn.getCallee()->stripPointerCasts() &&
-        &i != DFSanLoadCallbackFn.getCallee()->stripPointerCasts() &&
-        &i != DFSanStoreCallbackFn.getCallee()->stripPointerCasts() &&
-        &i != DFSanMemTransferCallbackFn.getCallee()->stripPointerCasts() &&
-        &i != DFSanCmpCallbackFn.getCallee()->stripPointerCasts())
+  for (Function &i : M)
+    if (!i.isIntrinsic() && !DFSanRuntimeFunctions.contains(&i))
       FnsToInstrument.push_back(&i);
-  }
 
   // Give function aliases prefixes when necessary, and build wrappers where the
   // instrumentedness is inconsistent.
   for (Module::alias_iterator i = M.alias_begin(), e = M.alias_end(); i != e;) {
     GlobalAlias *GA = &*i;
     ++i;
     // Don't stop on weak.  We assume people aren't playing games with the
     // instrumentedness of overridden weak aliases.