[Attributor][NFC] Make `createShallowWrapper()` available outside of Attributor

[sstefan1]

Summary

D85703 will need to create shallow wrappers in order to track the spmd icv. We need to make it available.

[jdoerfert]

llvm/include/llvm/Transforms/IPO/Attributor.h

1596

No need to move the code in the header, right? Just move the declaration here.

[sstefan1]

llvm/include/llvm/Transforms/IPO/Attributor.h

1596

Right...rushed this a bit, will update shortly.

[sstefan1]

Only move the declaration

[jdoerfert]

LGTM

llvm/include/llvm/Transforms/IPO/Attributor.h

struct Attributor {
   /// Check \p Pred on all Read/Write instructions.
   ///
   /// This method will evaluate \p Pred on all instructions that read or write
   /// to memory present in the information cache and return true if \p Pred
   /// holds on all of them.
   bool checkForAllReadWriteInstructions(function_ref<bool(Instruction &)> Pred,
                                         AbstractAttribute &QueryingAA);
 
+  /// Create a shallow wrapper for \p F such that \p F has internal linkage
+  /// afterwards. It also sets the original \p F 's name to anonymous
+  ///
+  /// A wrapper is a function with the same type (and attributes) as \p F
+  /// that will only call \p F and return the result, if any.
+  ///
+  /// Assuming the declaration of looks like:
+  ///   rty F(aty0 arg0, ..., atyN argN);
+  ///
+  /// The wrapper will then look as follows:
+  ///   rty wrapper(aty0 arg0, ..., atyN argN) {
+  ///     return F(arg0, ..., argN);
+  ///   }
+  ///
+  static void createShallowWrapper(Function &F) {
+    assert(!F.isDeclaration() &&
+           "Cannot create a wrapper around a declaration!");
+
+    Module &M = *F.getParent();
+    LLVMContext &Ctx = M.getContext();
+    FunctionType *FnTy = F.getFunctionType();
+
+    Function *Wrapper = Function::Create(FnTy, F.getLinkage(),
+                                         F.getAddressSpace(), F.getName());
+    F.setName(""); // set the inside function anonymous
+    M.getFunctionList().insert(F.getIterator(), Wrapper);
+
+    F.setLinkage(GlobalValue::InternalLinkage);
+
+    F.replaceAllUsesWith(Wrapper);
+    assert(F.use_empty() && "Uses remained after wrapper was created!");
+
+    // Move the COMDAT section to the wrapper.
+    // TODO: Check if we need to keep it for F as well.
+    Wrapper->setComdat(F.getComdat());
+    F.setComdat(nullptr);
+
+    // Copy all metadata and attributes but keep them on F as well.
+    SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
+    F.getAllMetadata(MDs);
+    for (auto MDIt : MDs)
+      Wrapper->addMetadata(MDIt.first, *MDIt.second);
+    Wrapper->setAttributes(F.getAttributes());
+
+    // Create the call in the wrapper.
+    BasicBlock *EntryBB = BasicBlock::Create(Ctx, "entry", Wrapper);
+
+    SmallVector<Value *, 8> Args;
+    Argument *FArgIt = F.arg_begin();
+    for (Argument &Arg : Wrapper->args()) {
+      Args.push_back(&Arg);
+      Arg.setName((FArgIt++)->getName());
+    }
+
+    CallInst *CI = CallInst::Create(&F, Args, "", EntryBB);
+    CI->setTailCall(true);
+    CI->addAttribute(AttributeList::FunctionIndex, Attribute::NoInline);
+    ReturnInst::Create(Ctx, CI->getType()->isVoidTy() ? nullptr : CI, EntryBB);
+  }
+
   /// Return the data layout associated with the anchor scope.
   const DataLayout &getDataLayout() const { return InfoCache.DL; }
 
   /// The allocator used to allocate memory, e.g. for `AbstractAttribute`s.
   BumpPtrAllocator &Allocator;
 
 private:
   /// This method will do fixpoint iteration until fixpoint or the

llvm/lib/Transforms/IPO/Attributor.cpp

 
 #define DEBUG_TYPE "attributor"
 
 STATISTIC(NumFnDeleted, "Number of function deleted");
 STATISTIC(NumFnWithExactDefinition,
           "Number of functions with exact definitions");
 STATISTIC(NumFnWithoutExactDefinition,
           "Number of functions without exact definitions");
-STATISTIC(NumFnShallowWrapperCreated, "Number of shallow wrappers created");
+STATISTIC(NumFnShallowWrappersCreated, "Number of shallow wrappers created");
 STATISTIC(NumAttributesTimedOut,
           "Number of abstract attributes timed out before fixpoint");
 STATISTIC(NumAttributesValidFixpoint,
           "Number of abstract attributes in a valid fixpoint state");
 STATISTIC(NumAttributesManifested,
           "Number of abstract attributes manifested in IR");
 STATISTIC(NumAttributesFixedDueToRequiredDependences,
           "Number of abstract attributes fixed due to required dependences");
ChangeStatus Attributor::updateAA(AbstractAttribute &AA) {
   // put there earlier.
   DependenceVector *PoppedDV = DependenceStack.pop_back_val();
   (void)PoppedDV;
   assert(PoppedDV == &DV && "Inconsistent usage of the dependence stack!");
 
   return CS;
 }
 
-/// Create a shallow wrapper for \p F such that \p F has internal linkage
-/// afterwards. It also sets the original \p F 's name to anonymous
-///
-/// A wrapper is a function with the same type (and attributes) as \p F
-/// that will only call \p F and return the result, if any.
-///
-/// Assuming the declaration of looks like:
-///   rty F(aty0 arg0, ..., atyN argN);
-///
-/// The wrapper will then look as follows:
-///   rty wrapper(aty0 arg0, ..., atyN argN) {
-///     return F(arg0, ..., argN);
-///   }
-///
-static void createShallowWrapper(Function &F) {
-  assert(AllowShallowWrappers &&
-         "Cannot create a wrapper if it is not allowed!");
-  assert(!F.isDeclaration() && "Cannot create a wrapper around a declaration!");
-
-  Module &M = *F.getParent();
-  LLVMContext &Ctx = M.getContext();
-  FunctionType *FnTy = F.getFunctionType();
-
-  Function *Wrapper =
-      Function::Create(FnTy, F.getLinkage(), F.getAddressSpace(), F.getName());
-  F.setName(""); // set the inside function anonymous
-  M.getFunctionList().insert(F.getIterator(), Wrapper);
-
-  F.setLinkage(GlobalValue::InternalLinkage);
-
-  F.replaceAllUsesWith(Wrapper);
-  assert(F.use_empty() && "Uses remained after wrapper was created!");
-
-  // Move the COMDAT section to the wrapper.
-  // TODO: Check if we need to keep it for F as well.
-  Wrapper->setComdat(F.getComdat());
-  F.setComdat(nullptr);
-
-  // Copy all metadata and attributes but keep them on F as well.
-  SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
-  F.getAllMetadata(MDs);
-  for (auto MDIt : MDs)
-    Wrapper->addMetadata(MDIt.first, *MDIt.second);
-  Wrapper->setAttributes(F.getAttributes());
-
-  // Create the call in the wrapper.
-  BasicBlock *EntryBB = BasicBlock::Create(Ctx, "entry", Wrapper);
-
-  SmallVector<Value *, 8> Args;
-  Argument *FArgIt = F.arg_begin();
-  for (Argument &Arg : Wrapper->args()) {
-    Args.push_back(&Arg);
-    Arg.setName((FArgIt++)->getName());
-  }
-
-  CallInst *CI = CallInst::Create(&F, Args, "", EntryBB);
-  CI->setTailCall(true);
-  CI->addAttribute(AttributeList::FunctionIndex, Attribute::NoInline);
-  ReturnInst::Create(Ctx, CI->getType()->isVoidTy() ? nullptr : CI, EntryBB);
-
-  NumFnShallowWrapperCreated++;
-}
-
 /// Make another copy of the function \p F such that the copied version has
 /// internal linkage afterwards and can be analysed. Then we replace all uses
 /// of the original function to the copied one
 ///
 /// Only non-exactly defined functions that have `linkonce_odr` or `weak_odr`
 /// linkage can be internalized because these linkages guarantee that other
 /// definitions with the same name have the same semantics as this one
 ///
static bool runAttributorOnFunctions(InformationCache &InfoCache,
   LLVM_DEBUG(dbgs() << "[Attributor] Run on module with " << Functions.size()
                     << " functions.\n");
 
   // Create an Attributor and initially empty information cache that is filled
   // while we identify default attribute opportunities.
   Attributor A(Functions, InfoCache, CGUpdater);
 
   // Create shallow wrappers for all functions that are not IPO amendable
-  if (AllowShallowWrappers)
-    for (Function *F : Functions)
-      if (!A.isFunctionIPOAmendable(*F))
-        createShallowWrapper(*F);
+  if (AllowShallowWrappers) {
+    for (Function *F : Functions) {
+      if (!A.isFunctionIPOAmendable(*F)) {
+        Attributor::createShallowWrapper(*F);
+        NumFnShallowWrappersCreated++;
+      }
+    }
+  }
 
   // Internalize non-exact functions
   // TODO: for now we eagerly internalize functions without calculating the
   //       cost, we need a cost interface to determine whether internalizing
   //       a function is "benefitial"
   if (AllowDeepWrapper) {
     unsigned FunSize = Functions.size();
     for (unsigned u = 0; u < FunSize; u++) {