C++ AnyFunctionRef::getCaptureInfo方法代码示例

ManagedValue
SILGenFunction::emitClosureValue(SILLocation loc, SILDeclRef constant,
                                 AnyFunctionRef TheClosure) {
  assert(((constant.uncurryLevel == 1 &&
           TheClosure.getCaptureInfo().hasLocalCaptures()) ||
          (constant.uncurryLevel == 0 &&
           !TheClosure.getCaptureInfo().hasLocalCaptures())) &&
         "curried local functions not yet supported");

  auto constantInfo = getConstantInfo(constant);
  SILValue functionRef = emitGlobalFunctionRef(loc, constant, constantInfo);
  SILType functionTy = functionRef->getType();

  auto expectedType =
    cast<FunctionType>(TheClosure.getType()->getCanonicalType());

  // Forward substitutions from the outer scope.

  auto pft = constantInfo.SILFnType;

  auto forwardSubs = constantInfo.getForwardingSubstitutions(getASTContext());

  bool wasSpecialized = false;
  if (pft->isPolymorphic() && !forwardSubs.empty()) {
    auto specialized = pft->substGenericArgs(F.getModule(),
                                             F.getModule().getSwiftModule(),
                                             forwardSubs);
    functionTy = SILType::getPrimitiveObjectType(specialized);
    wasSpecialized = true;
  }

  if (!TheClosure.getCaptureInfo().hasLocalCaptures() && !wasSpecialized) {
    auto result = ManagedValue::forUnmanaged(functionRef);
    return emitOrigToSubstValue(loc, result,
                                AbstractionPattern(expectedType),
                                expectedType);
  }

  SmallVector<ManagedValue, 4> capturedArgs;
  emitCaptures(loc, TheClosure, CaptureEmission::PartialApplication,
               capturedArgs);

  // The partial application takes ownership of the context parameters.
  SmallVector<SILValue, 4> forwardedArgs;
  for (auto capture : capturedArgs)
    forwardedArgs.push_back(capture.forward(*this));

  SILType closureTy =
    SILGenBuilder::getPartialApplyResultType(functionRef->getType(),
                                             capturedArgs.size(), SGM.M,
                                             forwardSubs);
  auto toClosure =
    B.createPartialApply(loc, functionRef, functionTy,
                         forwardSubs, forwardedArgs, closureTy);
  auto result = emitManagedRValueWithCleanup(toClosure);

  return emitOrigToSubstValue(loc, result,
                              AbstractionPattern(expectedType),
                              expectedType);
}

static unsigned getFuncNaturalUncurryLevel(AnyFunctionRef AFR) {
  assert(AFR.getParameterLists().size() >= 1 && "no arguments for func?!");
  unsigned Level = AFR.getParameterLists().size() - 1;
  // Functions with captures have an extra uncurry level for the capture
  // context.
  if (AFR.getCaptureInfo().hasLocalCaptures())
    Level += 1;
  return Level;
}

/// TODO: We should consult the cached LoweredLocalCaptures the SIL
/// TypeConverter calculates, but that would require plumbing SILModule&
/// through every SILDeclRef constructor. Since this is only used to determine
/// "natural uncurry level", and "uncurry level" is a concept we'd like to
/// phase out, it's not worth it.
static bool hasLoweredLocalCaptures(AnyFunctionRef AFR,
                                    llvm::DenseSet<AnyFunctionRef> &visited) {
  if (!AFR.getCaptureInfo().hasLocalCaptures())
    return false;
  
  // Scan for local, non-function captures.
  bool functionCapturesToRecursivelyCheck = false;
  auto addFunctionCapture = [&](AnyFunctionRef capture) {
    if (visited.find(capture) == visited.end())
      functionCapturesToRecursivelyCheck = true;
  };
  for (auto &capture : AFR.getCaptureInfo().getCaptures()) {
    if (!capture.getDecl()->getDeclContext()->isLocalContext())
      continue;
    // We transitively capture a local function's captures.
    if (auto func = dyn_cast<AbstractFunctionDecl>(capture.getDecl())) {
      addFunctionCapture(func);
      continue;
    }
    // We may either directly capture properties, or capture through their
    // accessors.
    if (auto var = dyn_cast<VarDecl>(capture.getDecl())) {
      switch (var->getStorageKind()) {
      case VarDecl::StoredWithTrivialAccessors:
        llvm_unreachable("stored local variable with trivial accessors?");

      case VarDecl::InheritedWithObservers:
        llvm_unreachable("inherited local variable?");

      case VarDecl::StoredWithObservers:
      case VarDecl::Addressed:
      case VarDecl::AddressedWithTrivialAccessors:
      case VarDecl::AddressedWithObservers:
      case VarDecl::ComputedWithMutableAddress:
        // Directly capture storage if we're supposed to.
        if (capture.isDirect())
          return true;

        // Otherwise, transitively capture the accessors.
        SWIFT_FALLTHROUGH;

      case VarDecl::Computed:
        addFunctionCapture(var->getGetter());
        if (auto setter = var->getSetter())
          addFunctionCapture(setter);
        continue;
      
      case VarDecl::Stored:
        return true;
      }
    }
    // Anything else is directly captured.
    return true;
  }
  
  // Recursively consider function captures, since we didn't have any direct
  // captures.
  auto captureHasLocalCaptures = [&](AnyFunctionRef capture) -> bool {
    if (visited.insert(capture).second)
      return hasLoweredLocalCaptures(capture, visited);
    return false;
  };
  
  if (functionCapturesToRecursivelyCheck) {
    for (auto &capture : AFR.getCaptureInfo().getCaptures()) {
      if (!capture.getDecl()->getDeclContext()->isLocalContext())
        continue;
      if (auto func = dyn_cast<AbstractFunctionDecl>(capture.getDecl())) {
        if (captureHasLocalCaptures(func))
          return true;
        continue;
      }
      if (auto var = dyn_cast<VarDecl>(capture.getDecl())) {
        switch (var->getStorageKind()) {
        case VarDecl::StoredWithTrivialAccessors:
          llvm_unreachable("stored local variable with trivial accessors?");
          
        case VarDecl::InheritedWithObservers:
          llvm_unreachable("inherited local variable?");
          
        case VarDecl::StoredWithObservers:
        case VarDecl::Addressed:
        case VarDecl::AddressedWithTrivialAccessors:
        case VarDecl::AddressedWithObservers:
        case VarDecl::ComputedWithMutableAddress:
          assert(!capture.isDirect() && "should have short circuited out");
          // Otherwise, transitively capture the accessors.
          SWIFT_FALLTHROUGH;
          
        case VarDecl::Computed:
          if (captureHasLocalCaptures(var->getGetter()))
            return true;
          if (auto setter = var->getSetter())
            if (captureHasLocalCaptures(setter))
              return true;
//.........这里部分代码省略.........