C++ SILGenFunction::emitManagedRValueWithCleanup方法代码示例

static void buildBlockToFuncThunkBody(SILGenFunction &gen,
                                      SILLocation loc,
                                      CanSILFunctionType blockTy,
                                      CanSILFunctionType funcTy) {
  // Collect the native arguments, which should all be +1.
  Scope scope(gen.Cleanups, CleanupLocation::get(loc));

  assert(blockTy->getParameters().size()
           == funcTy->getParameters().size()
         && "block and function types don't match");

  SmallVector<ManagedValue, 4> args;
  SILBasicBlock *entry = &*gen.F.begin();
  for (unsigned i : indices(funcTy->getParameters())) {
    auto &param = funcTy->getParameters()[i];
    auto &blockParam = blockTy->getParameters()[i];

    auto &tl = gen.getTypeLowering(param.getSILType());
    assert((tl.isTrivial()
              ? param.getConvention() == ParameterConvention::Direct_Unowned
              : param.getConvention() == ParameterConvention::Direct_Owned)
           && "nonstandard conventions for native functions not implemented");
    SILValue v = new (gen.SGM.M) SILArgument(entry, param.getSILType());
    auto mv = gen.emitManagedRValueWithCleanup(v, tl);
    args.push_back(gen.emitNativeToBridgedValue(loc, mv,
                              SILFunctionTypeRepresentation::Block,
                              AbstractionPattern(param.getType()),
                              param.getType(),
                              blockParam.getType()));
  }

  // Add the block argument.
  SILValue blockV
    = new (gen.SGM.M) SILArgument(entry,
                                  SILType::getPrimitiveObjectType(blockTy));
  ManagedValue block = gen.emitManagedRValueWithCleanup(blockV);

  // Call the block.
  assert(!funcTy->hasIndirectResult()
         && "block thunking func with indirect result not supported");
  ManagedValue result = gen.emitMonomorphicApply(loc, block, args,
                         funcTy->getSILResult().getSwiftRValueType(),
                         ApplyOptions::None,
                         /*override CC*/ SILFunctionTypeRepresentation::Block,
                         /*foreign error*/ None);

  // Return the result at +1.
  auto &resultTL = gen.getTypeLowering(funcTy->getSILResult());
  auto convention = funcTy->getResult().getConvention();
  assert((resultTL.isTrivial()
           ? convention == ResultConvention::Unowned
           : convention == ResultConvention::Owned)
         && "nonstandard conventions for return not implemented");
  (void)convention;
  (void)resultTL;

  auto r = result.forward(gen);
  scope.pop();
  gen.B.createReturn(loc, r);
}

static RValue emitImplicitValueConstructorArg(SILGenFunction &SGF,
                                              SILLocation loc,
                                              CanType interfaceType,
                                              DeclContext *DC) {
  auto type = DC->mapTypeIntoContext(interfaceType)->getCanonicalType();

  // Restructure tuple arguments.
  if (auto tupleTy = dyn_cast<TupleType>(interfaceType)) {
    RValue tuple(type);
    for (auto fieldType : tupleTy.getElementTypes())
      tuple.addElement(emitImplicitValueConstructorArg(SGF, loc, fieldType, DC));
    return tuple;
  }

  auto &AC = SGF.getASTContext();
  auto VD = new (AC) ParamDecl(VarDecl::Specifier::Default, SourceLoc(), SourceLoc(),
                               AC.getIdentifier("$implicit_value"),
                               SourceLoc(),
                               AC.getIdentifier("$implicit_value"), Type(),
                               DC);
  VD->setInterfaceType(interfaceType);
  SILFunctionArgument *arg =
      SGF.F.begin()->createFunctionArgument(SGF.getLoweredType(type), VD);
  ManagedValue mvArg;
  if (arg->getArgumentConvention().isOwnedConvention()) {
    mvArg = SGF.emitManagedRValueWithCleanup(arg);
  } else {
    mvArg = ManagedValue::forUnmanaged(arg);
  }
  return RValue(SGF, loc, type, mvArg);
}

static RValue emitImplicitValueConstructorArg(SILGenFunction &gen,
                                              SILLocation loc,
                                              CanType interfaceType,
                                              DeclContext *DC) {
  auto type = DC->mapTypeIntoContext(interfaceType)->getCanonicalType();

  // Restructure tuple arguments.
  if (CanTupleType tupleTy = dyn_cast<TupleType>(interfaceType)) {
    RValue tuple(type);
    for (auto fieldType : tupleTy.getElementTypes())
      tuple.addElement(emitImplicitValueConstructorArg(gen, loc, fieldType, DC));

    return tuple;
  } else {
    auto &AC = gen.getASTContext();
    auto VD = new (AC) ParamDecl(/*IsLet*/ true, SourceLoc(), SourceLoc(),
                                 AC.getIdentifier("$implicit_value"),
                                 SourceLoc(),
                                 AC.getIdentifier("$implicit_value"), Type(),
                                 DC);
    VD->setInterfaceType(interfaceType);
    SILValue arg =
        gen.F.begin()->createFunctionArgument(gen.getLoweredType(type), VD);
    return RValue(gen, loc, type, gen.emitManagedRValueWithCleanup(arg));
  }
}

static ManagedValue emitBridgeCollectionFromNative(SILGenFunction &gen,
                                                   SILLocation loc,
                                                   SILDeclRef bridgeFnRef,
                                                   ManagedValue collection,
                                                   SILType bridgedTy) {
  SILValue bridgeFn = gen.emitGlobalFunctionRef(loc, bridgeFnRef);

  // If the expected return is optional, we'll need to wrap it.
  OptionalTypeKind OTK = OTK_None;
  SILType origBridgedTy = bridgedTy;
  if (auto bridgedObjTy = bridgedTy.getAnyOptionalObjectType(gen.SGM.M, OTK)) {
    bridgedTy = bridgedObjTy;
  }

  // Figure out the type parameters.
  auto inputTy
    = collection.getType().getSwiftRValueType()->castTo<BoundGenericType>();
  auto subs = inputTy->getSubstitutions(gen.SGM.M.getSwiftModule(), nullptr);
  auto substFnType = bridgeFn.getType().substGenericArgs(gen.SGM.M, subs);
  SILValue bridged = gen.B.createApply(loc, bridgeFn,
                                       substFnType,
                                       bridgedTy,
                                       subs,
                                       { collection.forward(gen) });
  // Wrap the result if necessary.
  if (OTK != OTK_None) {
    bridged = gen.B.createEnum(loc, bridged,
                               gen.getASTContext().getOptionalSomeDecl(OTK),
                               origBridgedTy);
  }

  return gen.emitManagedRValueWithCleanup(bridged);
}

static ManagedValue emitBridgeCollectionToNative(SILGenFunction &gen,
                                                 SILLocation loc,
                                                 SILDeclRef bridgeFnRef,
                                                 ManagedValue collection,
                                                 SILType nativeTy) {
  SILValue bridgeFn = gen.emitGlobalFunctionRef(loc, bridgeFnRef);

  auto collectionTy = nativeTy.getSwiftRValueType()->castTo<BoundGenericType>();
  auto subs = collectionTy->getSubstitutions(gen.SGM.M.getSwiftModule(),
                                             nullptr);
  auto substFnType = bridgeFn.getType().substGenericArgs(gen.SGM.M, subs);

  Type inputType = collection.getType().getSwiftRValueType();
  if (!inputType->getOptionalObjectType()) {
    SILType loweredOptTy = gen.SGM.getLoweredType(OptionalType::get(inputType));
    auto *someDecl = gen.getASTContext().getOptionalSomeDecl();
    auto *enumInst = gen.B.createEnum(loc, collection.getValue(), someDecl,
                                      loweredOptTy);
    collection = ManagedValue(enumInst, collection.getCleanup());
  }

  SILValue result = gen.B.createApply(loc, bridgeFn,
                                      substFnType,
                                      nativeTy,
                                      subs,
                                      { collection.forward(gen) });

  return gen.emitManagedRValueWithCleanup(result);
}

/// Specialized emitter for Builtin.castReferenceFromBridgeObject.
static ManagedValue emitBuiltinCastReferenceFromBridgeObject(
                                                  SILGenFunction &gen,
                                                  SILLocation loc,
                                                  SubstitutionList subs,
                                                  ArrayRef<ManagedValue> args,
                                                  CanFunctionType formalApplyType,
                                                  SGFContext C) {
  assert(args.size() == 1 && "cast should have one argument");
  assert(subs.size() == 1 && "cast should have a type substitution");

  // The substitution determines the destination type.
  SILType destType = gen.getLoweredType(subs[0].getReplacement());
  
  // Bail if the source type is not a class reference of some kind.
  if (!subs[0].getReplacement()->isBridgeableObjectType()
      || !destType.isObject()) {
    gen.SGM.diagnose(loc, diag::invalid_sil_builtin,
                 "castReferenceFromBridgeObject dest must be an object type");
    // Recover by propagating an undef result.
    SILValue result = SILUndef::get(destType, gen.SGM.M);
    return ManagedValue::forUnmanaged(result);
  }
  
  SILValue result = gen.B.createBridgeObjectToRef(loc, args[0].forward(gen),
                                                  destType);
  return gen.emitManagedRValueWithCleanup(result);
}

/// Specialized emitter for Builtin.castReference.
static ManagedValue
emitBuiltinCastReference(SILGenFunction &gen,
                         SILLocation loc,
                         ArrayRef<Substitution> substitutions,
                         ArrayRef<ManagedValue> args,
                         CanFunctionType formalApplyType,
                         SGFContext C) {
  assert(args.size() == 1 && "castReference should be given one argument");
  assert(substitutions.size() == 2 && "castReference should have two subs");

  auto fromTy = substitutions[0].getReplacement();
  auto toTy = substitutions[1].getReplacement();
  auto &fromTL = gen.getTypeLowering(fromTy);
  auto &toTL = gen.getTypeLowering(toTy);
  assert(!fromTL.isTrivial() && !toTL.isTrivial() && "expected ref type");

  if (fromTL.isLoadable() || toTL.isLoadable()) { 
    if (auto refCast = gen.B.tryCreateUncheckedRefCast(loc, args[0].getValue(),
                                                       toTL.getLoweredType())) {
      // Create a reference cast, forwarding the cleanup.
      // The cast takes the source reference.
      return ManagedValue(refCast, args[0].getCleanup());
    }
  }
  // We are either casting between address-only types, or cannot promote to a
  // cast of reference values.
  //
  // If the from/to types are invalid, then use a cast that will fail at
  // runtime. We cannot catch these errors with SIL verification because they
  // may legitimately occur during code specialization on dynamically
  // unreachable paths.
  //
  // TODO: For now, we leave invalid casts in address form so that the runtime
  // will trap. We could emit a noreturn call here instead which would provide
  // more information to the optimizer.
  SILValue srcVal = args[0].forward(gen);
  SILValue fromAddr;
  if (fromTL.isLoadable()) {
    // Move the loadable value into a "source temp".  Since the source and
    // dest are RC identical, store the reference into the source temp without
    // a retain. The cast will load the reference from the source temp and
    // store it into a dest temp effectively forwarding the cleanup.
    fromAddr = gen.emitTemporaryAllocation(loc, srcVal->getType());
    gen.B.createStore(loc, srcVal, fromAddr);
  } else {
    // The cast loads directly from the source address.
    fromAddr = srcVal;
  }
  // Create a "dest temp" to hold the reference after casting it.
  SILValue toAddr = gen.emitTemporaryAllocation(loc, toTL.getLoweredType());
  gen.B.createUncheckedRefCastAddr(loc, fromAddr, fromTy->getCanonicalType(),
                                   toAddr, toTy->getCanonicalType());
  // Forward it along and register a cleanup.
  if (toTL.isAddressOnly())
    return gen.emitManagedBufferWithCleanup(toAddr);

  // Load the destination value.
  auto result = gen.B.createLoad(loc, toAddr);
  return gen.emitManagedRValueWithCleanup(result);
}

/// Emit a copy of this value with independent ownership.
ManagedValue ManagedValue::copy(SILGenFunction &gen, SILLocation l) {
  if (!cleanup.isValid()) {
    assert(gen.getTypeLowering(getType()).isTrivial());
    return *this;
  }
  
  auto &lowering = gen.getTypeLowering(getType());
  assert(!lowering.isTrivial() && "trivial value has cleanup?");
  
  if (!lowering.isAddressOnly()) {
    lowering.emitRetainValue(gen.B, l, getValue());
    return gen.emitManagedRValueWithCleanup(getValue(), lowering);
  }
  
  SILValue buf = gen.emitTemporaryAllocation(l, getType());
  gen.B.createCopyAddr(l, getValue(), buf, IsNotTake, IsInitialization);
  return gen.emitManagedRValueWithCleanup(buf, lowering);
}

/// This is the same operation as 'copy', but works on +0 values that don't
/// have cleanups.  It returns a +1 value with one.
ManagedValue ManagedValue::copyUnmanaged(SILGenFunction &SGF, SILLocation loc) {
  if (getType().isObject()) {
    return SGF.B.createCopyValue(loc, *this);
  }

  SILValue result = SGF.emitTemporaryAllocation(loc, getType());
  SGF.B.createCopyAddr(loc, getValue(), result, IsNotTake, IsInitialization);
  return SGF.emitManagedRValueWithCleanup(result);
}

static void boxIndirectEnumPayload(SILGenFunction &gen,
                                   ManagedValue &payload,
                                   SILLocation loc,
                                   EnumElementDecl *element) {
  // If the payload is indirect, we'll need to box it.
  if (payload && (element->isIndirect() ||
                  element->getParentEnum()->isIndirect())) {
    auto box = gen.B.createAllocBox(loc, payload.getType());
    payload.forwardInto(gen, loc, box->getAddressResult());
    payload = gen.emitManagedRValueWithCleanup(box);
  }
}

static SILValue emitBridgeReturnValue(SILGenFunction &gen,
                                      SILLocation loc,
                                      SILValue result,
                                      SILFunctionTypeRepresentation fnTypeRepr,
                                      CanType bridgedTy) {
  Scope scope(gen.Cleanups, CleanupLocation::get(loc));

  ManagedValue native = gen.emitManagedRValueWithCleanup(result);
  ManagedValue bridged = gen.emitNativeToBridgedValue(loc, native, fnTypeRepr,
                                      bridgedTy);
  return bridged.forward(gen);
}

/// Emit a copy of this value with independent ownership.
ManagedValue ManagedValue::copy(SILGenFunction &SGF, SILLocation loc) {
  auto &lowering = SGF.getTypeLowering(getType());
  if (lowering.isTrivial())
    return *this;

  if (getType().isObject()) {
    return SGF.B.createCopyValue(loc, *this, lowering);
  }

  SILValue buf = SGF.emitTemporaryAllocation(loc, getType());
  SGF.B.createCopyAddr(loc, getValue(), buf, IsNotTake, IsInitialization);
  return SGF.emitManagedRValueWithCleanup(buf, lowering);
}

static ManagedValue emitBridgeStringToNSString(SILGenFunction &gen,
                                               SILLocation loc,
                                               ManagedValue str) {
  // func _convertStringToNSString(String) -> NSString
  SILValue stringToNSStringFn
    = gen.emitGlobalFunctionRef(loc, gen.SGM.getStringToNSStringFn());

  SILValue nsstr = gen.B.createApply(loc, stringToNSStringFn,
                           stringToNSStringFn.getType(),
                           gen.getLoweredType(gen.SGM.Types.getNSStringType()),
                           {}, str.forward(gen));
  return gen.emitManagedRValueWithCleanup(nsstr);
}

static ManagedValue emitBridgeForeignBoolToBool(SILGenFunction &gen,
                                                SILLocation loc,
                                                ManagedValue foreignBool,
                                                SILDeclRef bridgingFnRef) {
  // func _convertObjCBoolToBool(ObjCBool) -> Bool
  SILValue bridgingFn = gen.emitGlobalFunctionRef(loc, bridgingFnRef);

  SILType resultTy = gen.getLoweredLoadableType(gen.SGM.Types.getBoolType());

  SILValue result = gen.B.createApply(loc, bridgingFn, bridgingFn->getType(),
                                      resultTy, {}, foreignBool.forward(gen));
  return gen.emitManagedRValueWithCleanup(result);
}

static ManagedValue emitBridgeBoolToObjCBool(SILGenFunction &gen,
                                             SILLocation loc,
                                             ManagedValue swiftBool) {
  // func _convertBoolToObjCBool(Bool) -> ObjCBool
  SILValue boolToObjCBoolFn
    = gen.emitGlobalFunctionRef(loc, gen.SGM.getBoolToObjCBoolFn());

  SILType resultTy =gen.getLoweredLoadableType(gen.SGM.Types.getObjCBoolType());

  SILValue result = gen.B.createApply(loc, boolToObjCBoolFn,
                                      boolToObjCBoolFn->getType(),
                                      resultTy, {}, swiftBool.forward(gen));
  return gen.emitManagedRValueWithCleanup(result);
}