[Attributor] [WIP] Introduce callbase context bridges.

[kuter]

Summary

This patch introduces the bridges between call base context and the callbase

[jdoerfert]

Can we include some code that triggers this so we can tests it?

[kuter]

In D83299#2140135, @jdoerfert wrote:

Can we include some code that triggers this so we can tests it?

D83744 uses this and has tests.

[kuter]

merged with D83744

llvm/lib/Transforms/IPO/AttributorAttributes.cpp

ChangeStatus clampStateAndIndicateChange(StateType &S, const StateType &R) {
   return Assumed == S.getAssumed() ? ChangeStatus::UNCHANGED
                                    : ChangeStatus::CHANGED;
 }
 
 /// Clamp the information known for all returned values of a function
 /// (identified by \p QueryingAA) into \p S.
 template <typename AAType, typename StateType = typename AAType::StateType>
 static void clampReturnedValueStates(Attributor &A, const AAType &QueryingAA,
-                                     StateType &S) {
+                                     StateType &S, const IRPosition::CallBaseContext *CBContext = nullptr) {
   LLVM_DEBUG(dbgs() << "[Attributor] Clamp return value states for "
                     << QueryingAA << " into " << S << "\n");
 
   assert((QueryingAA.getIRPosition().getPositionKind() ==
               IRPosition::IRP_RETURNED ||
           QueryingAA.getIRPosition().getPositionKind() ==
               IRPosition::IRP_CALL_SITE_RETURNED) &&
          "Can only clamp returned value states for a function returned or call "
          "site returned position!");
 
   // Use an optional state as there might not be any return values and we want
   // to join (IntegerState::operator&) the state of all there are.
   Optional<StateType> T;
 
   // Callback for each possibly returned value.
   auto CheckReturnValue = [&](Value &RV) -> bool {
-    const IRPosition &RVPos = IRPosition::value(RV);
+    const IRPosition &RVPos = IRPosition::value(RV, CBContext);
     const AAType &AA = A.getAAFor<AAType>(QueryingAA, RVPos);
     LLVM_DEBUG(dbgs() << "[Attributor] RV: " << RV << " AA: " << AA.getAsStr()
                       << " @ " << RVPos << "\n");
     const StateType &AAS = static_cast<const StateType &>(AA.getState());
     if (T.hasValue())
       *T &= AAS;
     else
       T = AAS;
     LLVM_DEBUG(dbgs() << "[Attributor] AA State: " << AAS << " RV State: " << T
                       << "\n");
     return T->isValidState();
   };
 
   if (!A.checkForAllReturnedValues(CheckReturnValue, QueryingAA))
     S.indicatePessimisticFixpoint();
   else if (T.hasValue())
     S ^= *T;
 }
 
 /// Helper class for generic deduction: return value -> returned position.
 template <typename AAType, typename BaseType,
-          typename StateType = typename BaseType::StateType>
+          typename StateType = typename BaseType::StateType, bool PropagateCallBaseContext = false>
 struct AAReturnedFromReturnedValues : public BaseType {
   AAReturnedFromReturnedValues(const IRPosition &IRP, Attributor &A)
       : BaseType(IRP, A) {}
 
   /// See AbstractAttribute::updateImpl(...).
   ChangeStatus updateImpl(Attributor &A) override {
     StateType S(StateType::getBestState(this->getState()));
-    clampReturnedValueStates<AAType, StateType>(A, *this, S);
+    clampReturnedValueStates<AAType, StateType>(A, *this, S, PropagateCallBaseContext ? this->getCallBaseContext() : nullptr);
     // TODO: If we know we visited all returned values, thus no are assumed
     // dead, we can take the known information from the state T.
     return clampStateAndIndicateChange<StateType>(this->getState(), S);
   }
 };
 
 /// Clamp the information known at all call sites for a given argument
 /// (identified by \p QueryingAA) into \p S.
static void clampCallSiteArgumentStates(Attributor &A, const AAType &QueryingAA,
   bool AllCallSitesKnown;
   if (!A.checkForAllCallSites(CallSiteCheck, QueryingAA, true,
                               AllCallSitesKnown))
     S.indicatePessimisticFixpoint();
   else if (T.hasValue())
     S ^= *T;
 }
 
-/// Helper class for generic deduction: call site argument -> argument position.
+/// This function is the bridge between argument position and the call base
+/// context.
 template <typename AAType, typename BaseType,
           typename StateType = typename AAType::StateType>
+bool getArgumentStateFromCallBaseContext(Attributor &A,
+                                         BaseType &QueryingAttribute,
+                                         IRPosition &Pos, StateType &State) {
+  assert((Pos.getPositionKind() == IRPosition::IRP_ARGUMENT) &&
+         "Expected a 'argument' position !");
+  const CallBase *CBContext = Pos.getCallBaseContext();
+  if (!CBContext)
+    return false;
+  int ArgNo = Pos.getArgNo();
+  if (ArgNo < 0)
+    return false;
+  Value *Val = CBContext->getArgOperand(ArgNo);
+  assert(Val && "CBContext argument value must not be nullptr!");
+
+  const StateType &CBArgumentState =
+      (const StateType &)A
+          .getAAFor<AAType>(QueryingAttribute, IRPosition::value(*Val))
+          .getState();
+
+  LLVM_DEBUG(dbgs() << "[Attributor] Briding Call site context to argument"
+                    << "Position:" << Pos << " Argument Value: " << Val
+                    << "CB Arg state:" << CBArgumentState << "\n");
+
+  // NOTE: If we want to do call site grouping it should happen here.
+  State ^= CBArgumentState;
+  return true;
+}
+
+/// Helper class for generic deduction: call site argument -> argument position.
+template <typename AAType, typename BaseType,
+          typename StateType = typename AAType::StateType,
+          bool BridgeCallBaseContext = false>
 struct AAArgumentFromCallSiteArguments : public BaseType {
   AAArgumentFromCallSiteArguments(const IRPosition &IRP, Attributor &A)
       : BaseType(IRP, A) {}
 
   /// See AbstractAttribute::updateImpl(...).
   ChangeStatus updateImpl(Attributor &A) override {
-    StateType S(StateType::getBestState(this->getState()));
+    StateType S = StateType::getBestState(this->getState());
+
+    if (BridgeCallBaseContext) {
+      bool Succsess =
+          getArgumentStateFromCallBaseContext<AAType, BaseType, StateType>(
+              A, *this, this->getIRPosition(), S);
+      if (Succsess)
+        return clampStateAndIndicateChange<StateType>(this->getState(), S);
+    }
     clampCallSiteArgumentStates<AAType, StateType>(A, *this, S);
+
     // TODO: If we know we visited all incoming values, thus no are assumed
     // dead, we can take the known information from the state T.
     return clampStateAndIndicateChange<StateType>(this->getState(), S);
   }
 };
 
 /// Helper class for generic replication: function returned -> cs returned.
 template <typename AAType, typename BaseType,
-          typename StateType = typename BaseType::StateType>
+          typename StateType = typename BaseType::StateType, bool IntroduceCallBaseContext = false>
 struct AACallSiteReturnedFromReturned : public BaseType {
   AACallSiteReturnedFromReturned(const IRPosition &IRP, Attributor &A)
       : BaseType(IRP, A) {}
 
   /// See AbstractAttribute::updateImpl(...).
   ChangeStatus updateImpl(Attributor &A) override {
     assert(this->getIRPosition().getPositionKind() ==
                IRPosition::IRP_CALL_SITE_RETURNED &&
            "Can only wrap function returned positions for call site returned "
            "positions!");
     auto &S = this->getState();
 
     const Function *AssociatedFunction =
         this->getIRPosition().getAssociatedFunction();
     if (!AssociatedFunction)
       return S.indicatePessimisticFixpoint();
 
-    IRPosition FnPos = IRPosition::returned(*AssociatedFunction);
+    CallBase *CBContext = (CallBase*)&this->getAnchorValue();
+    if (IntroduceCallBaseContext)
+      LLVM_DEBUG(dbgs() << "[Attributor] Introducing call base context:" << *CBContext << "\n");
+
+    IRPosition FnPos = IRPosition::returned(*AssociatedFunction, IntroduceCallBaseContext ? CBContext : nullptr);
     const AAType &AA = A.getAAFor<AAType>(*this, FnPos);
     return clampStateAndIndicateChange(
         S, static_cast<const StateType &>(AA.getState()));
   }
 };
 
 /// Helper function to accumulate uses.
 template <class AAType, typename StateType = typename AAType::StateType>