C++ SILFunction类代码示例

/// \brief Inlines all mandatory inlined functions into the body of a function,
/// first recursively inlining all mandatory apply instructions in those
/// functions into their bodies if necessary.
///
/// \param F the function to be processed
/// \param AI nullptr if this is being called from the top level; the relevant
///   ApplyInst requiring the recursive call when non-null
/// \param FullyInlinedSet the set of all functions already known to be fully
///   processed, to avoid processing them over again
/// \param SetFactory an instance of ImmutableFunctionSet::Factory
/// \param CurrentInliningSet the set of functions currently being inlined in
///   the current call stack of recursive calls
///
/// \returns true if successful, false if failed due to circular inlining.
static bool
runOnFunctionRecursively(SILFunction *F, FullApplySite AI,
                         SILModule::LinkingMode Mode,
                         DenseFunctionSet &FullyInlinedSet,
                         ImmutableFunctionSet::Factory &SetFactory,
                         ImmutableFunctionSet CurrentInliningSet,
                         ClassHierarchyAnalysis *CHA) {
  // Avoid reprocessing functions needlessly.
  if (FullyInlinedSet.count(F))
    return true;

  // Prevent attempt to circularly inline.
  if (CurrentInliningSet.contains(F)) {
    // This cannot happen on a top-level call, so AI should be non-null.
    assert(AI && "Cannot have circular inline without apply");
    SILLocation L = AI.getLoc();
    assert(L && "Must have location for transparent inline apply");
    diagnose(F->getModule().getASTContext(), L.getStartSourceLoc(),
             diag::circular_transparent);
    return false;
  }

  // Add to the current inlining set (immutably, so we only affect the set
  // during this call and recursive subcalls).
  CurrentInliningSet = SetFactory.add(CurrentInliningSet, F);

  SmallVector<SILValue, 16> CaptureArgs;
  SmallVector<SILValue, 32> FullArgs;

  for (auto FI = F->begin(), FE = F->end(); FI != FE; ++FI) {
    for (auto I = FI->begin(), E = FI->end(); I != E; ++I) {
      FullApplySite InnerAI = FullApplySite::isa(&*I);

      if (!InnerAI)
        continue;

      auto *ApplyBlock = InnerAI.getParent();

      auto NewInstPair = tryDevirtualizeApply(InnerAI, CHA);
      if (auto *NewInst = NewInstPair.first) {
        replaceDeadApply(InnerAI, NewInst);
        if (auto *II = dyn_cast<SILInstruction>(NewInst))
          I = II->getIterator();
        else
          I = NewInst->getParentBlock()->begin();
        auto NewAI = FullApplySite::isa(NewInstPair.second.getInstruction());
        if (!NewAI)
          continue;

        InnerAI = NewAI;
      }

      SILLocation Loc = InnerAI.getLoc();
      SILValue CalleeValue = InnerAI.getCallee();
      bool IsThick;
      PartialApplyInst *PAI;
      SILFunction *CalleeFunction = getCalleeFunction(InnerAI, IsThick,
                                                      CaptureArgs, FullArgs,
                                                      PAI,
                                                      Mode);
      if (!CalleeFunction ||
          CalleeFunction->isTransparent() == IsNotTransparent)
        continue;

      if (F->isFragile() &&
          !CalleeFunction->hasValidLinkageForFragileRef()) {
        if (!CalleeFunction->hasValidLinkageForFragileInline()) {
          llvm::errs() << "caller: " << F->getName() << "\n";
          llvm::errs() << "callee: " << CalleeFunction->getName() << "\n";
          llvm_unreachable("Should never be inlining a resilient function into "
                           "a fragile function");
        }
        continue;
      }

      // Then recursively process it first before trying to inline it.
      if (!runOnFunctionRecursively(CalleeFunction, InnerAI, Mode,
                                    FullyInlinedSet, SetFactory,
                                    CurrentInliningSet, CHA)) {
        // If we failed due to circular inlining, then emit some notes to
        // trace back the failure if we have more information.
        // FIXME: possibly it could be worth recovering and attempting other
        // inlines within this same recursive call rather than simply
        // propagating the failure.
        if (AI) {
          SILLocation L = AI.getLoc();
//.........这里部分代码省略.........

void MaterializeForSetEmitter::emit(SILGenFunction &gen, ManagedValue self,
                                    SILValue resultBuffer,
                                    SILValue callbackBuffer,
                                    ArrayRef<ManagedValue> indices) {
  SILLocation loc = Witness;
  loc.markAutoGenerated();

  // If there's an abstraction difference, we always need to use the
  // get/set pattern.
  AccessStrategy strategy;
  if (WitnessStorage->getType()->is<ReferenceStorageType>() ||
      (Conformance && RequirementStorageType != WitnessStorageType)) {
    strategy = AccessStrategy::DispatchToAccessor;
  } else {
    strategy = WitnessStorage->getAccessStrategy(TheAccessSemantics,
                                                 AccessKind::ReadWrite);
  }

  // Handle the indices.
  RValue indicesRV;
  if (isa<SubscriptDecl>(WitnessStorage)) {
    indicesRV = collectIndicesFromParameters(gen, loc, indices);
  } else {
    assert(indices.empty() && "indices for a non-subscript?");
  }

  // As above, assume that we don't need to reabstract 'self'.

  // Choose the right implementation.
  SILValue address;
  SILFunction *callbackFn = nullptr;
  switch (strategy) {
  case AccessStrategy::Storage:
    address = emitUsingStorage(gen, loc, self, std::move(indicesRV));
    break;

  case AccessStrategy::Addressor:
    address = emitUsingAddressor(gen, loc, self, std::move(indicesRV),
                                 callbackBuffer, callbackFn);
    break;

  case AccessStrategy::DirectToAccessor:
  case AccessStrategy::DispatchToAccessor:
    address = emitUsingGetterSetter(gen, loc, self, std::move(indicesRV),
                                    resultBuffer, callbackBuffer, callbackFn);
    break;
  }

  // Return the address as a Builtin.RawPointer.
  SILType rawPointerTy = SILType::getRawPointerType(gen.getASTContext());
  address = gen.B.createAddressToPointer(loc, address, rawPointerTy);

  SILType resultTupleTy = gen.F.mapTypeIntoContext(
                 gen.F.getLoweredFunctionType()->getResult().getSILType());
  SILType optCallbackTy = resultTupleTy.getTupleElementType(1);

  // Form the callback.
  SILValue callback;
  if (callbackFn) {
    // Make a reference to the function.
    callback = gen.B.createFunctionRef(loc, callbackFn);

    // If it's polymorphic, cast to RawPointer and then back to the
    // right monomorphic type.  The safety of this cast relies on some
    // assumptions about what exactly IRGen can reconstruct from the
    // callback's thick type argument.
    if (callbackFn->getLoweredFunctionType()->isPolymorphic()) {
      callback = gen.B.createThinFunctionToPointer(loc, callback, rawPointerTy);

      OptionalTypeKind optKind;
      auto callbackTy = optCallbackTy.getAnyOptionalObjectType(SGM.M, optKind);
      callback = gen.B.createPointerToThinFunction(loc, callback, callbackTy);
    }

    callback = gen.B.createOptionalSome(loc, callback, optCallbackTy);
  } else {
    callback = gen.B.createOptionalNone(loc, optCallbackTy);
  }

  // Form the result and return.
  auto result = gen.B.createTuple(loc, resultTupleTy, { address, callback });
  gen.Cleanups.emitCleanupsForReturn(CleanupLocation::get(loc));
  gen.B.createReturn(loc, result);
}

/// \brief Make sure that all parameters are passed with a reference count
/// neutral parameter convention except for self.
bool swift::ArraySemanticsCall::isValidSignature() {
  assert(SemanticsCall && getKind() != ArrayCallKind::kNone &&
         "Need an array semantic call");
  FunctionRefInst *FRI = cast<FunctionRefInst>(SemanticsCall->getCallee());
  SILFunction *F = FRI->getReferencedFunction();
  auto FnTy = F->getLoweredFunctionType();
  auto &Mod = F->getModule();

  // Check whether we have a valid signature for semantic calls that we hoist.
  switch (getKind()) {
  // All other calls can be consider valid.
  default: break;
  case ArrayCallKind::kArrayPropsIsNativeTypeChecked: {
    // @guaranteed/@owned Self
    if (SemanticsCall->getNumArguments() != 1)
      return false;
    auto SelfConvention = FnTy->getSelfParameter().getConvention();
    return SelfConvention == ParameterConvention::Direct_Guaranteed ||
           SelfConvention == ParameterConvention::Direct_Owned;
  }
  case ArrayCallKind::kCheckIndex: {
    // Int, @guaranteed/@owned Self
    if (SemanticsCall->getNumArguments() != 2 ||
        !SemanticsCall->getArgument(0).getType().isTrivial(Mod))
      return false;
    auto SelfConvention = FnTy->getSelfParameter().getConvention();
    return SelfConvention == ParameterConvention::Direct_Guaranteed ||
           SelfConvention == ParameterConvention::Direct_Owned;
  }
  case ArrayCallKind::kCheckSubscript: {
    // Int, Bool, Self
    if (SemanticsCall->getNumArguments() != 3 ||
        !SemanticsCall->getArgument(0).getType().isTrivial(Mod))
      return false;
    if (!SemanticsCall->getArgument(1).getType().isTrivial(Mod))
      return false;
    auto SelfConvention = FnTy->getSelfParameter().getConvention();
    return SelfConvention == ParameterConvention::Direct_Guaranteed ||
           SelfConvention == ParameterConvention::Direct_Owned;
  }
  case ArrayCallKind::kMakeMutable: {
    auto SelfConvention = FnTy->getSelfParameter().getConvention();
    return SelfConvention == ParameterConvention::Indirect_Inout;
  }
  case ArrayCallKind::kArrayUninitialized: {
    // Make sure that if we are a _adoptStorage call that our storage is
    // uniquely referenced by us.
    SILValue Arg0 = SemanticsCall->getArgument(0);
    if (Arg0.getType().isExistentialType()) {
      auto *AllocBufferAI = dyn_cast<ApplyInst>(Arg0);
      if (!AllocBufferAI)
        return false;

      auto *AllocFn = AllocBufferAI->getCalleeFunction();
      if (!AllocFn)
        return false;

      StringRef AllocFuncName = AllocFn->getName();
      if (AllocFuncName != "swift_bufferAllocate" &&
          AllocFuncName != "swift_bufferAllocateOnStack")
        return false;

      if (!hasOneNonDebugUse(*AllocBufferAI))
        return false;
    }
    return true;
  }
  }

  return true;
}

bool Devirtualizer::devirtualizeAppliesInFunction(SILFunction &F,
                                                  ClassHierarchyAnalysis *CHA) {
  bool Changed = false;
  llvm::SmallVector<SILInstruction *, 8> DeadApplies;
  llvm::SmallVector<ApplySite, 8> NewApplies;

  for (auto &BB : F) {
    for (auto It = BB.begin(), End = BB.end(); It != End;) {
      auto &I = *It++;

      // Skip non-apply instructions.

      auto Apply = FullApplySite::isa(&I);
      if (!Apply)
        continue;

      auto NewInstPair = tryDevirtualizeApply(Apply, CHA);
      if (!NewInstPair.second)
        continue;

      Changed = true;

      auto *AI = Apply.getInstruction();
      if (!isa<TryApplyInst>(AI))
        AI->replaceAllUsesWith(NewInstPair.first);

      DeadApplies.push_back(AI);
      NewApplies.push_back(NewInstPair.second);
    }
  }

  // Remove all the now-dead applies.
  while (!DeadApplies.empty()) {
    auto *AI = DeadApplies.pop_back_val();
    recursivelyDeleteTriviallyDeadInstructions(AI, true);
  }

  // For each new apply, attempt to link in function bodies if we do
  // not already have them, then notify the pass manager of the new
  // functions.
  //
  // We do this after deleting the old applies because otherwise we
  // hit verification errors in the linking code due to having
  // non-cond_br critical edges.
  while (!NewApplies.empty()) {
    auto Apply = NewApplies.pop_back_val();

    auto *CalleeFn = Apply.getReferencedFunction();
    assert(CalleeFn && "Expected devirtualized callee!");

    // FIXME: Until we link everything in up front we need to ensure
    // that we link after devirtualizing in order to pull in
    // everything we reference from the stdlib. After we do that we
    // can move the notification code below back into the main loop
    // above.
    if (!CalleeFn->isDefinition())
      F.getModule().linkFunction(CalleeFn, SILModule::LinkingMode::LinkAll);

    // We may not have optimized these functions yet, and it could
    // be beneficial to rerun some earlier passes on the current
    // function now that we've made these direct references visible.
    if (CalleeFn->isDefinition() && CalleeFn->shouldOptimize())
      notifyPassManagerOfFunction(CalleeFn, nullptr);
  }

  return Changed;
}

SILFunction *SILModule::findFunction(StringRef Name, SILLinkage Linkage) {
  assert((Linkage == SILLinkage::Public ||
          Linkage == SILLinkage::PublicExternal) &&
         "Only a lookup of public functions is supported currently");

  SILFunction *F = nullptr;

  // First, check if there is a function with a required name in the
  // current module.
  SILFunction *CurF = lookUpFunction(Name);

  // Nothing to do if the current module has a required function
  // with a proper linkage already.
  if (CurF && CurF->getLinkage() == Linkage) {
    F = CurF;
  } else {
    assert((!CurF || CurF->getLinkage() != Linkage) &&
           "hasFunction should be only called for functions that are not "
           "contained in the SILModule yet or do not have a required linkage");
  }

  if (!F) {
    SILLinkerVisitor Visitor(*this, getSILLoader(),
                             SILModule::LinkingMode::LinkNormal);
    if (CurF) {
      // Perform this lookup only if a function with a given
      // name is present in the current module.
      // This is done to reduce the amount of IO from the
      // swift module file.
      if (!Visitor.hasFunction(Name, Linkage))
        return nullptr;
      // The function in the current module will be changed.
      F = CurF;
    }

    // If function with a given name wasn't seen anywhere yet
    // or if it is known to exist, perform a lookup.
    if (!F) {
      // Try to load the function from other modules.
      F = Visitor.lookupFunction(Name, Linkage);
      // Bail if nothing was found and we are not sure if
      // this function exists elsewhere.
      if (!F)
        return nullptr;
      assert(F && "SILFunction should be present in one of the modules");
      assert(F->getLinkage() == Linkage && "SILFunction has a wrong linkage");
    }
  }

  // If a function exists already and it is a non-optimizing
  // compilation, simply convert it into an external declaration,
  // so that a compiled version from the shared library is used.
  if (F->isDefinition() &&
      F->getModule().getOptions().Optimization <
          SILOptions::SILOptMode::Optimize) {
    F->convertToDeclaration();
  }
  if (F->isExternalDeclaration())
    F->setSerialized(IsSerialized_t::IsNotSerialized);
  F->setLinkage(Linkage);
  return F;
}

void FunctionSignatureTransform::ArgumentExplosionFinalizeOptimizedFunction() {
  SILFunction *NewF = TransformDescriptor.OptimizedFunction.get();
  SILBasicBlock *BB = &*NewF->begin();
  SILBuilder Builder(BB->begin());
  Builder.setCurrentDebugScope(BB->getParent()->getDebugScope());
  unsigned TotalArgIndex = 0;
  for (ArgumentDescriptor &AD : TransformDescriptor.ArgumentDescList) {
    // If this argument descriptor was dead and we removed it, just skip it. Do
    // not increment the argument index.
    if (AD.WasErased) {
      continue;
    }

    // Simply continue if do not explode.
    if (!AD.Explode) {
      TransformDescriptor.AIM[TotalArgIndex] = AD.Index;
      ++TotalArgIndex;
      continue;
    }

    assert(!AD.IsEntirelyDead &&
           "Should never see completely dead values here");

    // OK, we need to explode this argument.
    unsigned ArgOffset = ++TotalArgIndex;
    unsigned OldArgIndex = ArgOffset - 1;
    llvm::SmallVector<SILValue, 8> LeafValues;

    // We do this in the same order as leaf types since ProjTree expects that
    // the order of leaf values matches the order of leaf types.
    llvm::SmallVector<const ProjectionTreeNode *, 8> LeafNodes;
    AD.ProjTree.getLiveLeafNodes(LeafNodes);

    for (auto *Node : LeafNodes) {
      auto OwnershipKind = *AD.getTransformedOwnershipKind(Node->getType());
      LeafValues.push_back(
          BB->insertFunctionArgument(ArgOffset, Node->getType(), OwnershipKind,
                                     BB->getArgument(OldArgIndex)->getDecl()));
      TransformDescriptor.AIM[TotalArgIndex - 1] = AD.Index;
      ++ArgOffset;
      ++TotalArgIndex;
    }

    // Then go through the projection tree constructing aggregates and replacing
    // uses.
    AD.ProjTree.replaceValueUsesWithLeafUses(
        Builder, BB->getParent()->getLocation(), LeafValues);

    // We ignored debugvalue uses when we constructed the new arguments, in
    // order to preserve as much information as possible, we construct a new
    // value for OrigArg from the leaf values and use that in place of the
    // OrigArg.
    SILValue NewOrigArgValue = AD.ProjTree.computeExplodedArgumentValue(
        Builder, BB->getParent()->getLocation(), LeafValues);

    // Replace all uses of the original arg with the new value.
    SILArgument *OrigArg = BB->getArgument(OldArgIndex);
    OrigArg->replaceAllUsesWith(NewOrigArgValue);

    // Now erase the old argument since it does not have any uses. We also
    // decrement ArgOffset since we have one less argument now.
    BB->eraseArgument(OldArgIndex);
    --TotalArgIndex;
  }
}

// Returns the callee of an apply_inst if it is basically inlineable.
SILFunction *SILPerformanceInliner::getEligibleFunction(FullApplySite AI) {

  SILFunction *Callee = AI.getReferencedFunction();

  if (!Callee) {
    return nullptr;
  }

  // Don't inline functions that are marked with the @_semantics or @effects
  // attribute if the inliner is asked not to inline them.
  if (Callee->hasSemanticsAttrs() || Callee->hasEffectsKind()) {
    if (WhatToInline == InlineSelection::NoSemanticsAndGlobalInit) {
      return nullptr;
    }
    // The "availability" semantics attribute is treated like global-init.
    if (Callee->hasSemanticsAttrs() &&
        WhatToInline != InlineSelection::Everything &&
        Callee->hasSemanticsAttrThatStartsWith("availability")) {
      return nullptr;
    }
  } else if (Callee->isGlobalInit()) {
    if (WhatToInline != InlineSelection::Everything) {
      return nullptr;
    }
  }

  // We can't inline external declarations.
  if (Callee->empty() || Callee->isExternalDeclaration()) {
    return nullptr;
  }

  // Explicitly disabled inlining.
  if (Callee->getInlineStrategy() == NoInline) {
    return nullptr;
  }
  
  if (!Callee->shouldOptimize()) {
    return nullptr;
  }

  // We don't support this yet.
  if (AI.hasSubstitutions()) {
    return nullptr;
  }

  // We don't support inlining a function that binds dynamic self because we
  // have no mechanism to preserve the original function's local self metadata.
  if (computeMayBindDynamicSelf(Callee)) {
    return nullptr;
  }

  SILFunction *Caller = AI.getFunction();

  // Detect self-recursive calls.
  if (Caller == Callee) {
    return nullptr;
  }

  // A non-fragile function may not be inlined into a fragile function.
  if (Caller->isFragile() && !Callee->isFragile()) {
    return nullptr;
  }

  // Inlining self-recursive functions into other functions can result
  // in excessive code duplication since we run the inliner multiple
  // times in our pipeline
  if (calleeIsSelfRecursive(Callee)) {
    return nullptr;
  }

  return Callee;
}

/// Remove retain/release pairs around builtin "unsafeGuaranteed" instruction
/// sequences.
static bool removeGuaranteedRetainReleasePairs(SILFunction &F,
                                               RCIdentityFunctionInfo &RCIA) {
  DEBUG(llvm::dbgs() << "Running on function " << F.getName() << "\n");
  bool Changed = false;
  for (auto &BB : F) {
    auto It = BB.begin(), End = BB.end();
    llvm::DenseMap<SILValue, SILInstruction *> LastRetain;
    while (It != End) {
      auto *CurInst = &*It;
      ++It;

      // Memorize the last retain.
      if (isa<StrongRetainInst>(CurInst) || isa<RetainValueInst>(CurInst)) {
        LastRetain[RCIA.getRCIdentityRoot(CurInst->getOperand(0))] = CurInst;
        continue;
      }

      // Look for a builtin "unsafeGuaranteed" instruction.
      auto *UnsafeGuaranteedI = dyn_cast<BuiltinInst>(CurInst);
      if (!UnsafeGuaranteedI || !UnsafeGuaranteedI->getBuiltinKind() ||
          *UnsafeGuaranteedI->getBuiltinKind() !=
              BuiltinValueKind::UnsafeGuaranteed)
        continue;

      auto Opd = UnsafeGuaranteedI->getOperand(0);
      auto RCIdOpd = RCIA.getRCIdentityRoot(UnsafeGuaranteedI->getOperand(0));
      if (!LastRetain.count(RCIdOpd)) {
        DEBUG(llvm::dbgs() << "LastRetain failed\n");
        continue;
      }

      // This code is very conservative. Check that there is a matching retain
      // before the unsafeGuaranteed builtin with only retains inbetween.
      auto *LastRetainInst = LastRetain[RCIdOpd];
      auto NextInstIter = std::next(SILBasicBlock::iterator(LastRetainInst));
      while (NextInstIter != BB.end() && &*NextInstIter != CurInst &&
             (isa<RetainValueInst>(*NextInstIter) ||
              isa<StrongRetainInst>(*NextInstIter) ||
              !NextInstIter->mayHaveSideEffects() ||
              isa<DebugValueInst>(*NextInstIter) ||
              isa<DebugValueAddrInst>(*NextInstIter)))
       ++NextInstIter;
      if (&*NextInstIter != CurInst) {
        DEBUG(llvm::dbgs() << "Last retain right before match failed\n");
        continue;
      }

      DEBUG(llvm::dbgs() << "Saw " << *UnsafeGuaranteedI);
      DEBUG(llvm::dbgs() << "  with operand " << *Opd);

      // Match the reference and token result.
      //  %4 = builtin "unsafeGuaranteed"<Foo>(%0 : $Foo)
      //  %5 = tuple_extract %4 : $(Foo, Builtin.Int8), 0
      //  %6 = tuple_extract %4 : $(Foo, Builtin.Int8), 1
      SILInstruction *UnsafeGuaranteedValue;
      SILInstruction *UnsafeGuaranteedToken;
      std::tie(UnsafeGuaranteedValue, UnsafeGuaranteedToken) =
          getSingleUnsafeGuaranteedValueResult(UnsafeGuaranteedI);

      if (!UnsafeGuaranteedValue) {
        DEBUG(llvm::dbgs() << "  no single unsafeGuaranteed value use\n");
        continue;
      }

      // Look for a builtin "unsafeGuaranteedEnd" instruction that uses the
      // token.
      //   builtin "unsafeGuaranteedEnd"(%6 : $Builtin.Int8) : $()
      BuiltinInst *UnsafeGuaranteedEndI = nullptr;
      for (auto *Operand : getNonDebugUses(UnsafeGuaranteedToken)) {
        if (UnsafeGuaranteedEndI) {
          DEBUG(llvm::dbgs() << "  multiple unsafeGuaranteedEnd users\n");
          UnsafeGuaranteedEndI = nullptr;
          break;
        }
        auto *BI = dyn_cast<BuiltinInst>(Operand->getUser());
        if (!BI || !BI->getBuiltinKind() ||
            *BI->getBuiltinKind() != BuiltinValueKind::UnsafeGuaranteedEnd) {
          DEBUG(llvm::dbgs() << "  wrong unsafeGuaranteed token user "
                             << *Operand->getUser());
          break;
        }

        UnsafeGuaranteedEndI = BI;
      }

      if (!UnsafeGuaranteedEndI) {
        DEBUG(llvm::dbgs() << "  no single unsafeGuaranteedEnd use found\n");
        continue;
      }

      if (SILBasicBlock::iterator(UnsafeGuaranteedEndI) ==
          UnsafeGuaranteedEndI->getParent()->end())
        continue;

      // Find the release to match with the unsafeGuaranteedValue.
      auto &UnsafeGuaranteedEndBB = *UnsafeGuaranteedEndI->getParent();
      auto LastRelease = findReleaseToMatchUnsafeGuaranteedValue(
          UnsafeGuaranteedEndI, UnsafeGuaranteedI, UnsafeGuaranteedValue,
//.........这里部分代码省略.........

/// Bridge argument types and adjust retain count conventions for an ObjC thunk.
static SILFunctionType *emitObjCThunkArguments(SILGenFunction &gen,
                                               SILLocation loc,
                                               SILDeclRef thunk,
                                               SmallVectorImpl<SILValue> &args,
                                               SILValue &foreignErrorSlot,
                              Optional<ForeignErrorConvention> &foreignError) {
  SILDeclRef native = thunk.asForeign(false);

  auto mod = gen.SGM.M.getSwiftModule();
  auto subs = gen.F.getForwardingSubstitutions();

  auto objcInfo = gen.SGM.Types.getConstantInfo(thunk);
  auto objcFnTy = objcInfo.SILFnType->substGenericArgs(gen.SGM.M, mod, subs);

  auto swiftInfo = gen.SGM.Types.getConstantInfo(native);
  auto swiftFnTy = swiftInfo.SILFnType->substGenericArgs(gen.SGM.M, mod, subs);

  // We must have the same context archetypes as the unthunked function.
  assert(objcInfo.ContextGenericParams == swiftInfo.ContextGenericParams);

  SmallVector<ManagedValue, 8> bridgedArgs;
  bridgedArgs.reserve(objcFnTy->getParameters().size());

  SILFunction *orig = gen.SGM.getFunction(native, NotForDefinition);

  // Find the foreign error convention if we have one.
  if (orig->getLoweredFunctionType()->hasErrorResult()) {
    auto func = cast<AbstractFunctionDecl>(thunk.getDecl());
    foreignError = func->getForeignErrorConvention();
    assert(foreignError && "couldn't find foreign error convention!");
  }

  // Emit the indirect result arguments, if any.
  // FIXME: we're just assuming that these match up exactly?
  for (auto indirectResult : objcFnTy->getIndirectResults()) {
    SILType argTy = gen.F.mapTypeIntoContext(indirectResult.getSILType());
    auto arg = new (gen.F.getModule()) SILArgument(gen.F.begin(), argTy);
    args.push_back(arg);
  }

  // Emit the other arguments, taking ownership of arguments if necessary.
  auto inputs = objcFnTy->getParameters();
  auto nativeInputs = swiftFnTy->getParameters();
  assert(inputs.size() ==
           nativeInputs.size() + unsigned(foreignError.hasValue()));
  for (unsigned i = 0, e = inputs.size(); i < e; ++i) {
    SILType argTy = gen.F.mapTypeIntoContext(inputs[i].getSILType());
    SILValue arg = new(gen.F.getModule()) SILArgument(gen.F.begin(), argTy);

    // If this parameter is the foreign error slot, pull it out.
    // It does not correspond to a native argument.
    if (foreignError && i == foreignError->getErrorParameterIndex()) {
      foreignErrorSlot = arg;
      continue;
    }

    // If this parameter is deallocating, emit an unmanaged rvalue and
    // continue. The object has the deallocating bit set so retain, release is
    // irrelevant.
    if (inputs[i].isDeallocating()) {
      bridgedArgs.push_back(ManagedValue::forUnmanaged(arg));
      continue;
    }

    // If the argument is a block, copy it.
    if (argTy.isBlockPointerCompatible()) {
      auto copy = gen.B.createCopyBlock(loc, arg);
      // If the argument is consumed, we're still responsible for releasing the
      // original.
      if (inputs[i].isConsumed())
        gen.emitManagedRValueWithCleanup(arg);
      arg = copy;
    }
    // Convert the argument to +1 if necessary.
    else if (!inputs[i].isConsumed()) {
      arg = emitObjCUnconsumedArgument(gen, loc, arg);
    }

    auto managedArg = gen.emitManagedRValueWithCleanup(arg);

    bridgedArgs.push_back(managedArg);
  }

  assert(bridgedArgs.size() + unsigned(foreignError.hasValue())
           == objcFnTy->getParameters().size() &&
         "objc inputs don't match number of arguments?!");
  assert(bridgedArgs.size() == swiftFnTy->getNumSILArguments() &&
         "swift inputs don't match number of arguments?!");
  assert((foreignErrorSlot || !foreignError) &&
         "didn't find foreign error slot");

  // Bridge the input types.
  Scope scope(gen.Cleanups, CleanupLocation::get(loc));
  assert(bridgedArgs.size() == nativeInputs.size());
  for (unsigned i = 0, size = bridgedArgs.size(); i < size; ++i) {
    SILType argTy = gen.F.mapTypeIntoContext(
                           swiftFnTy->getParameters()[i].getSILType());
    ManagedValue native =
      gen.emitBridgedToNativeValue(loc,
//.........这里部分代码省略.........

// Returns the callee of an apply_inst if it is basically inlineable.
SILFunction *SILPerformanceInliner::getEligibleFunction(FullApplySite AI) {

  SILFunction *Callee = AI.getReferencedFunction();

  if (!Callee) {
    return nullptr;
  }

  // Don't inline functions that are marked with the @_semantics or @effects
  // attribute if the inliner is asked not to inline them.
  if (Callee->hasSemanticsAttrs() || Callee->hasEffectsKind()) {
    if (WhatToInline == InlineSelection::NoSemanticsAndGlobalInit) {
      return nullptr;
    }
    // The "availability" semantics attribute is treated like global-init.
    if (Callee->hasSemanticsAttrs() &&
        WhatToInline != InlineSelection::Everything &&
        Callee->hasSemanticsAttrThatStartsWith("availability")) {
      return nullptr;
    }
  } else if (Callee->isGlobalInit()) {
    if (WhatToInline != InlineSelection::Everything) {
      return nullptr;
    }
  }

  // We can't inline external declarations.
  if (Callee->empty() || Callee->isExternalDeclaration()) {
    return nullptr;
  }

  // Explicitly disabled inlining.
  if (Callee->getInlineStrategy() == NoInline) {
    return nullptr;
  }
  
  if (!Callee->shouldOptimize()) {
    return nullptr;
  }

  // We don't support this yet.
  if (AI.hasSubstitutions())
    return nullptr;

  SILFunction *Caller = AI.getFunction();

  // We don't support inlining a function that binds dynamic self because we
  // have no mechanism to preserve the original function's local self metadata.
  if (mayBindDynamicSelf(Callee)) {
    // Check if passed Self is the same as the Self of the caller.
    // In this case, it is safe to inline because both functions
    // use the same Self.
    if (AI.hasSelfArgument() && Caller->hasSelfParam()) {
      auto CalleeSelf = stripCasts(AI.getSelfArgument());
      auto CallerSelf = Caller->getSelfArgument();
      if (CalleeSelf != SILValue(CallerSelf))
        return nullptr;
    } else
      return nullptr;
  }

  // Detect self-recursive calls.
  if (Caller == Callee) {
    return nullptr;
  }

  // A non-fragile function may not be inlined into a fragile function.
  if (Caller->isFragile() &&
      !Callee->hasValidLinkageForFragileInline()) {
    if (!Callee->hasValidLinkageForFragileRef()) {
      llvm::errs() << "caller: " << Caller->getName() << "\n";
      llvm::errs() << "callee: " << Callee->getName() << "\n";
      llvm_unreachable("Should never be inlining a resilient function into "
                       "a fragile function");
    }
    return nullptr;
  }

  // Inlining self-recursive functions into other functions can result
  // in excessive code duplication since we run the inliner multiple
  // times in our pipeline
  if (calleeIsSelfRecursive(Callee)) {
    return nullptr;
  }

  return Callee;
}

bool SILPerformanceInliner::isProfitableToInline(FullApplySite AI,
                                                 Weight CallerWeight,
                                                 ConstantTracker &callerTracker,
                                                 int &NumCallerBlocks,
                                                 bool IsGeneric) {
  SILFunction *Callee = AI.getReferencedFunction();
  SILLoopInfo *LI = LA->get(Callee);
  ShortestPathAnalysis *SPA = getSPA(Callee, LI);
  assert(SPA->isValid());

  ConstantTracker constTracker(Callee, &callerTracker, AI);
  DominanceInfo *DT = DA->get(Callee);
  SILBasicBlock *CalleeEntry = &Callee->front();
  DominanceOrder domOrder(CalleeEntry, DT, Callee->size());

  // Calculate the inlining cost of the callee.
  int CalleeCost = 0;
  int Benefit = 0;
  
  // Start with a base benefit.
  int BaseBenefit = RemovedCallBenefit;
  const SILOptions &Opts = Callee->getModule().getOptions();
  
  // For some reason -Ounchecked can accept a higher base benefit without
  // increasing the code size too much.
  if (Opts.Optimization == SILOptions::SILOptMode::OptimizeUnchecked)
    BaseBenefit *= 2;

  CallerWeight.updateBenefit(Benefit, BaseBenefit);

  // Go through all blocks of the function, accumulate the cost and find
  // benefits.
  while (SILBasicBlock *block = domOrder.getNext()) {
    constTracker.beginBlock();
    Weight BlockW = SPA->getWeight(block, CallerWeight);

    for (SILInstruction &I : *block) {
      constTracker.trackInst(&I);
      
      CalleeCost += (int)instructionInlineCost(I);

      if (FullApplySite AI = FullApplySite::isa(&I)) {
        
        // Check if the callee is passed as an argument. If so, increase the
        // threshold, because inlining will (probably) eliminate the closure.
        SILInstruction *def = constTracker.getDefInCaller(AI.getCallee());
        if (def && (isa<FunctionRefInst>(def) || isa<PartialApplyInst>(def)))
          BlockW.updateBenefit(Benefit, RemovedClosureBenefit);
      } else if (auto *LI = dyn_cast<LoadInst>(&I)) {
        // Check if it's a load from a stack location in the caller. Such a load
        // might be optimized away if inlined.
        if (constTracker.isStackAddrInCaller(LI->getOperand()))
          BlockW.updateBenefit(Benefit, RemovedLoadBenefit);
      } else if (auto *SI = dyn_cast<StoreInst>(&I)) {
        // Check if it's a store to a stack location in the caller. Such a load
        // might be optimized away if inlined.
        if (constTracker.isStackAddrInCaller(SI->getDest()))
          BlockW.updateBenefit(Benefit, RemovedStoreBenefit);
      } else if (isa<StrongReleaseInst>(&I) || isa<ReleaseValueInst>(&I)) {
        SILValue Op = stripCasts(I.getOperand(0));
        if (SILArgument *Arg = dyn_cast<SILArgument>(Op)) {
          if (Arg->isFunctionArg() && Arg->getArgumentConvention() ==
              SILArgumentConvention::Direct_Guaranteed) {
            BlockW.updateBenefit(Benefit, RefCountBenefit);
          }
        }
      } else if (auto *BI = dyn_cast<BuiltinInst>(&I)) {
        if (BI->getBuiltinInfo().ID == BuiltinValueKind::OnFastPath)
          BlockW.updateBenefit(Benefit, FastPathBuiltinBenefit);
      }
    }
    // Don't count costs in blocks which are dead after inlining.
    SILBasicBlock *takenBlock = constTracker.getTakenBlock(block->getTerminator());
    if (takenBlock) {
      BlockW.updateBenefit(Benefit, RemovedTerminatorBenefit);
      domOrder.pushChildrenIf(block, [=] (SILBasicBlock *child) {
        return child->getSinglePredecessor() != block || child == takenBlock;
      });
    } else {
      domOrder.pushChildren(block);
    }
  }

  if (AI.getFunction()->isThunk()) {
    // Only inline trivial functions into thunks (which will not increase the
    // code size).
    if (CalleeCost > TrivialFunctionThreshold)
      return false;

    DEBUG(
      
      dumpCaller(AI.getFunction());
      llvm::dbgs() << "    decision {" << CalleeCost << " into thunk} " <<
          Callee->getName() << '\n';
    );
    return true;
  }

/// Specialize a partial_apply by promoting the parameters indicated by
/// indices. We expect these parameters to be replaced by stack address
/// references.
static PartialApplyInst *
specializePartialApply(PartialApplyInst *PartialApply,
                       ParamIndexList &PromotedParamIndices,
                       bool &CFGChanged) {
  auto *FRI = cast<FunctionRefInst>(PartialApply->getCallee());
  assert(FRI && "Expected a direct partial_apply!");
  auto *F = FRI->getReferencedFunction();
  assert(F && "Expected a referenced function!");

  IsFragile_t Fragile = IsNotFragile;
  if (PartialApply->getFunction()->isFragile() && F->isFragile())
    Fragile = IsFragile;

  std::string ClonedName = getClonedName(F, Fragile, PromotedParamIndices);

  auto &M = PartialApply->getModule();

  SILFunction *ClonedFn;
  if (auto *PrevFn = M.lookUpFunction(ClonedName)) {
    assert(PrevFn->isFragile() == Fragile);
    ClonedFn = PrevFn;
  } else {
    // Clone the function the existing partial_apply references.
    PromotedParamCloner Cloner(F, Fragile, PromotedParamIndices, ClonedName);
    Cloner.populateCloned();
    ClonedFn = Cloner.getCloned();
  }

  // Now create the new partial_apply using the cloned function.
  llvm::SmallVector<SILValue, 16> Args;

  ValueLifetimeAnalysis::Frontier PAFrontier;

  // Promote the arguments that need promotion.
  for (auto &O : PartialApply->getArgumentOperands()) {
    auto ParamIndex = getParameterIndexForOperand(&O);
    if (!count(PromotedParamIndices, ParamIndex)) {
      Args.push_back(O.get());
      continue;
    }

    // If this argument is promoted, it is a box that we're
    // turning into an address because we've proven we can
    // keep this value on the stack. The partial_apply had ownership
    // of this box so we must now release it explicitly when the
    // partial_apply is released.
    auto box = cast<AllocBoxInst>(O.get());

    // If the box address has a MUI, route accesses through it so DI still
    // works.
    SILInstruction *promoted = nullptr;
    int numAddrUses = 0;
    for (Operand *BoxUse : box->getUses()) {
      if (auto *PBI = dyn_cast<ProjectBoxInst>(BoxUse->getUser())) {
        for (auto PBIUse : PBI->getUses()) {
          numAddrUses++;
          if (auto MUI = dyn_cast<MarkUninitializedInst>(PBIUse->getUser()))
            promoted = MUI;
        }
      }
    }
    assert((!promoted || numAddrUses == 1) &&
           "box value used by mark_uninitialized but not exclusively!");
    
    // We only reuse an existing project_box if it directly follows the
    // alloc_box. This makes sure that the project_box dominates the
    // partial_apply.
    if (!promoted)
      promoted = getOrCreateProjectBox(box);

    Args.push_back(promoted);

    if (PAFrontier.empty()) {
      ValueLifetimeAnalysis VLA(PartialApply);
      CFGChanged |= !VLA.computeFrontier(PAFrontier,
                                      ValueLifetimeAnalysis::AllowToModifyCFG);
      assert(!PAFrontier.empty() && "partial_apply must have at least one use "
                                    "to release the returned function");
    }

    // Insert releases after each point where the partial_apply becomes dead.
    for (SILInstruction *FrontierInst : PAFrontier) {
      SILBuilderWithScope Builder(FrontierInst);
      Builder.emitStrongReleaseAndFold(PartialApply->getLoc(), O.get());
    }
  }

  SILBuilderWithScope Builder(PartialApply);

  // Build the function_ref and partial_apply.
  SILValue FunctionRef = Builder.createFunctionRef(PartialApply->getLoc(),
                                                   ClonedFn);
  CanSILFunctionType CanFnTy = ClonedFn->getLoweredFunctionType();
  auto const &Subs = PartialApply->getSubstitutions();
  CanSILFunctionType SubstCalleeTy = CanFnTy->substGenericArgs(M,
                                                             M.getSwiftModule(),
                                                             Subs);
//.........这里部分代码省略.........

/// Analyze the destructor for the class of ARI to see if any instructions in it
/// could have side effects on the program outside the destructor. If it does
/// not, then we can eliminate the destructor.
static bool doesDestructorHaveSideEffects(AllocRefInst *ARI) {
  SILFunction *Fn = getDestructor(ARI);
  // If we can't find a constructor then assume it has side effects.
  if (!Fn)
    return true;

  // A destructor only has one argument, self.
  assert(Fn->begin()->getNumArguments() == 1 &&
         "Destructor should have only one argument, self.");
  SILArgument *Self = Fn->begin()->getArgument(0);

  LLVM_DEBUG(llvm::dbgs() << "    Analyzing destructor.\n");

  // For each BB in the destructor...
  for (auto &BB : *Fn)
    // For each instruction I in BB...
    for (auto &I : BB) {
      LLVM_DEBUG(llvm::dbgs() << "        Visiting: " << I);

      // If I has no side effects, we can ignore it.
      if (!I.mayHaveSideEffects()) {
        LLVM_DEBUG(llvm::dbgs() << "            SAFE! Instruction has no side "
                   "effects.\n");
        continue;
      }

      // RefCounting operations on Self are ok since we are already in the
      // destructor. RefCountingOperations on other instructions could have side
      // effects though.
      if (auto *RefInst = dyn_cast<RefCountingInst>(&I)) {
        if (stripCasts(RefInst->getOperand(0)) == Self) {
          // For now all ref counting insts have 1 operand. Put in an assert
          // just in case.
          assert(RefInst->getNumOperands() == 1 &&
                 "Make sure RefInst only has one argument.");
          LLVM_DEBUG(llvm::dbgs() << "            SAFE! Ref count operation on "
                     "Self.\n");
          continue;
        } else {
          LLVM_DEBUG(llvm::dbgs() << "            UNSAFE! Ref count operation "
                     "not on self.\n");
          return true;
        }
      }

      // dealloc_stack can be ignored.
      if (isa<DeallocStackInst>(I)) {
        LLVM_DEBUG(llvm::dbgs() << "            SAFE! dealloc_stack can be "
                   "ignored.\n");
        continue;
      }

      // dealloc_ref on self can be ignored, but dealloc_ref on anything else
      // cannot be eliminated.
      if (auto *DeallocRef = dyn_cast<DeallocRefInst>(&I)) {
        if (stripCasts(DeallocRef->getOperand()) == Self) {
          LLVM_DEBUG(llvm::dbgs() <<"            SAFE! dealloc_ref on self.\n");
          continue;
        } else {
          LLVM_DEBUG(llvm::dbgs() << "            UNSAFE! dealloc_ref on value "
                     "besides self.\n");
          return true;
        }
      }

      // Storing into the object can be ignored.
      if (auto *SI = dyn_cast<StoreInst>(&I))
        if (stripAddressProjections(SI->getDest()) == Self) {
          LLVM_DEBUG(llvm::dbgs() << "            SAFE! Instruction is a store "
                     "into self.\n");
          continue;
        }

      LLVM_DEBUG(llvm::dbgs() << "            UNSAFE! Unknown instruction.\n");
      // Otherwise, we can't remove the deallocation completely.
      return true;
    }

  // We didn't find any side effects.
  return false;
}

/// Specialize a partial_apply by promoting the parameters indicated by
/// indices. We expect these parameters to be replaced by stack address
/// references.
static PartialApplyInst *
specializePartialApply(PartialApplyInst *PartialApply,
                       ParamIndexList &PromotedParamIndices) {
  auto *FRI = cast<FunctionRefInst>(PartialApply->getCallee());
  assert(FRI && "Expected a direct partial_apply!");
  auto *F = FRI->getReferencedFunction();
  assert(F && "Expected a referenced function!");

  std::string ClonedName = getClonedName(F, PromotedParamIndices);

  auto &M = PartialApply->getModule();

  SILFunction *ClonedFn;
  if (auto *PrevFn = M.lookUpFunction(ClonedName)) {
    ClonedFn = PrevFn;
  } else {
    // Clone the function the existing partial_apply references.
    PromotedParamCloner Cloner(F, PromotedParamIndices, ClonedName);
    Cloner.populateCloned();
    ClonedFn = Cloner.getCloned();
  }

  // Now create the new partial_apply using the cloned function.
  llvm::SmallVector<SILValue, 16> Args;

  LifetimeTracker Lifetime(PartialApply);

  // Promote the arguments that need promotion.
  for (auto &O : PartialApply->getArgumentOperands()) {
    auto ParamIndex = getParameterIndexForOperand(&O);
    if (!std::count(PromotedParamIndices.begin(), PromotedParamIndices.end(),
                    ParamIndex)) {
      Args.push_back(O.get());
      continue;
    }

    auto Endpoints = Lifetime.getEndpoints();

    // If this argument is promoted, it is a box that we're
    // turning into an address because we've proven we can
    // keep this value on the stack. The partial_apply had ownership
    // of this box so we must now release it explicitly when the
    // partial_apply is released.
    auto box = cast<AllocBoxInst>(O.get());

    // If the box address has a MUI, route accesses through it so DI still
    // works.
    SILInstruction *promoted = nullptr;
    int numAddrUses = 0;
    for (Operand *BoxUse : box->getUses()) {
      if (auto *PBI = dyn_cast<ProjectBoxInst>(BoxUse->getUser())) {
        for (auto PBIUse : PBI->getUses()) {
          numAddrUses++;
          if (auto MUI = dyn_cast<MarkUninitializedInst>(PBIUse->getUser()))
            promoted = MUI;
        }
      }
    }
    assert((!promoted || numAddrUses == 1) &&
           "box value used by mark_uninitialized but not exclusively!");
    
    // We only reuse an existing project_box if it directly follows the
    // alloc_box. This makes sure that the project_box dominates the
    // partial_apply.
    if (!promoted)
      promoted = getOrCreateProjectBox(box);

    Args.push_back(promoted);

    // If the partial_apply is dead, insert a release after it.
    if (Endpoints.begin() == Endpoints.end()) {
      emitStrongReleaseAfter(O.get(), PartialApply);
      continue;
    }

    // Otherwise insert releases after each point where the
    // partial_apply becomes dead.
    for (auto *User : Endpoints) {
      assert((isa<StrongReleaseInst>(User) || isa<ApplyInst>(User)) &&
             "Unexpected end of lifetime for partial_apply!");
      emitStrongReleaseAfter(O.get(), User);
    }
  }

  SILBuilderWithScope Builder(PartialApply);

  // Build the function_ref and partial_apply.
  SILValue FunctionRef = Builder.createFunctionRef(PartialApply->getLoc(),
                                                   ClonedFn);
  CanSILFunctionType CanFnTy = ClonedFn->getLoweredFunctionType();
  auto const &Subs = PartialApply->getSubstitutions();
  CanSILFunctionType SubstCalleeTy = CanFnTy->substGenericArgs(M,
                                                             M.getSwiftModule(),
                                                             Subs);
  return Builder.createPartialApply(PartialApply->getLoc(), FunctionRef,
                                 SILType::getPrimitiveObjectType(SubstCalleeTy),
                                    PartialApply->getSubstitutions(), Args,
//.........这里部分代码省略.........

void ClosureSpecializer::gatherCallSites(
    SILFunction *Caller,
    llvm::SmallVectorImpl<ClosureInfo*> &ClosureCandidates,
    llvm::DenseSet<FullApplySite> &MultipleClosureAI) {

  // A set of apply inst that we have associated with a closure. We use this to
  // make sure that we do not handle call sites with multiple closure arguments.
  llvm::DenseSet<FullApplySite> VisitedAI;

  // For each basic block BB in Caller...
  for (auto &BB : *Caller) {

    // For each instruction II in BB...
    for (auto &II : BB) {
      // If II is not a closure that we support specializing, skip it...
      if (!isSupportedClosure(&II))
        continue;

      ClosureInfo *CInfo = nullptr;

      // Go through all uses of our closure.
      for (auto *Use : II.getUses()) {
        // If this use is not an apply inst or an apply inst with
        // substitutions, there is nothing interesting for us to do, so
        // continue...
        auto AI = FullApplySite::isa(Use->getUser());
        if (!AI || AI.hasSubstitutions())
          continue;

        // Check if we have already associated this apply inst with a closure to
        // be specialized. We do not handle applies that take in multiple
        // closures at this time.
        if (!VisitedAI.insert(AI).second) {
          MultipleClosureAI.insert(AI);
          continue;
        }

        // If AI does not have a function_ref definition as its callee, we can
        // not do anything here... so continue...
        SILFunction *ApplyCallee = AI.getReferencedFunction();
        if (!ApplyCallee || ApplyCallee->isExternalDeclaration())
          continue;

        // Ok, we know that we can perform the optimization but not whether or
        // not the optimization is profitable. Find the index of the argument
        // corresponding to our partial apply.
        Optional<unsigned> ClosureIndex;
        for (unsigned i = 0, e = AI.getNumArguments(); i != e; ++i) {
          if (AI.getArgument(i) != SILValue(&II))
            continue;
          ClosureIndex = i;
          DEBUG(llvm::dbgs() << "    Found callsite with closure argument at "
                << i << ": " << *AI.getInstruction());
          break;
        }

        // If we did not find an index, there is nothing further to do,
        // continue.
        if (!ClosureIndex.hasValue())
          continue;

        // Make sure that the Closure is invoked in the Apply's callee. We only
        // want to perform closure specialization if we know that we will be
        // able to change a partial_apply into an apply.
        //
        // TODO: Maybe just call the function directly instead of moving the
        // partial apply?
        SILValue Arg = ApplyCallee->getArgument(ClosureIndex.getValue());
        if (std::none_of(Arg->use_begin(), Arg->use_end(),
                         [&Arg](Operand *Op) -> bool {
                           auto UserAI = FullApplySite::isa(Op->getUser());
                           return UserAI && UserAI.getCallee() == Arg;
                         })) {
          continue;
        }

        auto NumIndirectResults =
          AI.getSubstCalleeType()->getNumIndirectResults();
        assert(ClosureIndex.getValue() >= NumIndirectResults);
        auto ClosureParamIndex = ClosureIndex.getValue() - NumIndirectResults;

        auto ParamInfo = AI.getSubstCalleeType()->getParameters();
        SILParameterInfo ClosureParamInfo = ParamInfo[ClosureParamIndex];

        // Get all non-failure exit BBs in the Apply Callee if our partial apply
        // is guaranteed. If we do not understand one of the exit BBs, bail.
        //
        // We need this to make sure that we insert a release in the appropriate
        // locations to balance the +1 from the creation of the partial apply.
        llvm::TinyPtrVector<SILBasicBlock *> NonFailureExitBBs;
        if (ClosureParamInfo.isGuaranteed() &&
            !findAllNonFailureExitBBs(ApplyCallee, NonFailureExitBBs)) {
          continue;
        }

        // Compute the final release points of the closure. We will insert
        // release of the captured arguments here.
        if (!CInfo) {
          CInfo = new ClosureInfo(&II);
          ValueLifetimeAnalysis VLA(CInfo->Closure);
//.........这里部分代码省略.........