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

void ArgumentSource::forwardInto(SILGenFunction &SGF,
                                 AbstractionPattern origFormalType,
                                 Initialization *dest,
                                 const TypeLowering &destTL) && {
  auto substFormalType = getSubstType();
  assert(destTL.getLoweredType() ==
                        SGF.getLoweredType(origFormalType, substFormalType));

  // If there are no abstraction changes, we can just forward
  // normally.
  if (origFormalType.isExactType(substFormalType) ||
      destTL.getLoweredType() == SGF.getLoweredType(substFormalType)) {
    std::move(*this).forwardInto(SGF, dest);
    return;
  }

  // Otherwise, emit as a single independent value.
  SILLocation loc = getLocation();
  ManagedValue inputValue = std::move(*this).getAsSingleValue(SGF);

  // Reabstract.
  ManagedValue outputValue =
    SGF.emitSubstToOrigValue(loc, inputValue, origFormalType,
                             substFormalType, SGFContext(dest));
  if (outputValue.isInContext()) return;

  // Use RValue's forward-into-initialization code.  We have to lie to
  // RValue about the formal type (by using the lowered type) because
  // we're emitting into an abstracted value, which RValue doesn't
  // really handle.
  auto substLoweredType = destTL.getLoweredType().getSwiftRValueType();
  RValue(SGF, loc, substLoweredType, outputValue).forwardInto(SGF, dest, loc);
}

ManagedValue ArgumentSource::getAsSingleValue(SILGenFunction &gen,
                                              AbstractionPattern origFormalType,
                                              SGFContext C) && {
  auto loc = getLocation();
  auto substFormalType = getSubstType();
  ManagedValue outputValue = std::move(*this).getAsSingleValue(gen);
  return gen.emitSubstToOrigValue(loc,
                                  outputValue, origFormalType,
                                  substFormalType, C);
}

static ManagedValue
adjustForConditionalCheckedCastOperand(SILLocation loc, ManagedValue src,
                                       CanType sourceType, CanType targetType,
                                       SILGenFunction &SGF) {
  // Reabstract to the most general abstraction, and put it into a
  // temporary if necessary.
  
  // Figure out if we need the value to be in a temporary.
  bool requiresAddress =
    !canUseScalarCheckedCastInstructions(SGF.SGM.M, sourceType, targetType);
  
  AbstractionPattern abstraction = SGF.SGM.M.Types.getMostGeneralAbstraction();
  auto &srcAbstractTL = SGF.getTypeLowering(abstraction, sourceType);
  
  bool hasAbstraction = (src.getType() != srcAbstractTL.getLoweredType());
  
  // Fast path: no re-abstraction required.
  if (!hasAbstraction && (!requiresAddress || src.getType().isAddress())) {
    return src;
  }
  
  std::unique_ptr<TemporaryInitialization> init;
  SGFContext ctx;
  if (requiresAddress) {
    init = SGF.emitTemporary(loc, srcAbstractTL);
    
    // Okay, if all we need to do is drop the value in an address,
    // this is easy.
    if (!hasAbstraction) {
      SGF.B.createStore(loc, src.forward(SGF), init->getAddress());
      init->finishInitialization(SGF);
      return init->getManagedAddress();
    }
    
    ctx = SGFContext(init.get());
  }
  
  assert(hasAbstraction);
  assert(src.getType().isObject() &&
         "address-only type with abstraction difference?");
  
  // Produce the value at +1.
  return SGF.emitSubstToOrigValue(loc, src, abstraction, sourceType);
}

RValue Lowering::emitConditionalCheckedCast(SILGenFunction &SGF,
                                            SILLocation loc,
                                            ManagedValue operand,
                                            Type operandType,
                                            Type optTargetType,
                                            CheckedCastKind castKind,
                                            SGFContext C) {
  // Drill into the result type.
  OptionalTypeKind optKind;
  CanType resultObjectType =
    optTargetType->getCanonicalType().getAnyOptionalObjectType(optKind);
  assert(resultObjectType);

  // Handle collection downcasts directly; they have specific library
  // entry points.
  if (castKind == CheckedCastKind::ArrayDowncast ||
      castKind == CheckedCastKind::DictionaryDowncast ||
      castKind == CheckedCastKind::SetDowncast) {
    return emitCollectionDowncastExpr(SGF, operand, operandType, loc,
                                      resultObjectType, C,
                                      /*conditional=*/true);
  }

  operand = adjustForConditionalCheckedCastOperand(loc, operand,
                                               operandType->getCanonicalType(),
                                                   resultObjectType, SGF);

  auto someDecl = SGF.getASTContext().getOptionalSomeDecl(optKind);
  auto &resultTL = SGF.getTypeLowering(optTargetType);

  // Optional<T> currently fully abstracts its object.
  auto abstraction = SGF.SGM.Types.getMostGeneralAbstraction();
  auto &abstractResultObjectTL =
    SGF.getTypeLowering(abstraction, resultObjectType);
  auto &resultObjectTL = SGF.getTypeLowering(resultObjectType);
  bool hasAbstraction =
    (resultObjectTL.getLoweredType() != abstractResultObjectTL.getLoweredType());

  // Set up a result buffer if desirable/required.
  SILValue resultBuffer;
  SILValue resultObjectBuffer;
  Optional<TemporaryInitialization> resultObjectTemp;
  SGFContext resultObjectCtx;
  if (resultTL.isAddressOnly() ||
      (!hasAbstraction && C.getEmitInto() &&
       C.getEmitInto()->getAddressOrNull())) {
    resultBuffer = SGF.getBufferForExprResult(loc, resultTL.getLoweredType(), C);
    resultObjectBuffer =
      SGF.B.createInitEnumDataAddr(loc, resultBuffer, someDecl,
                     abstractResultObjectTL.getLoweredType().getAddressType());
    resultObjectTemp.emplace(resultObjectBuffer, CleanupHandle::invalid());

    if (!hasAbstraction)
      resultObjectCtx = SGFContext(&resultObjectTemp.getValue());
  }

  // Prepare a jump destination here.
  ExitableFullExpr scope(SGF, CleanupLocation::get(loc));

  auto operandCMV = ConsumableManagedValue::forOwned(operand);
  SGF.emitCheckedCastBranch(loc, operandCMV, operandType,
                            resultObjectType, resultObjectCtx,
    // The success path.
    [&](ManagedValue objectValue) {
      // If we're not emitting into a temporary, just wrap up the result
      // in Some and go to the continuation block.
      if (!resultObjectTemp) {
        if (hasAbstraction)
          objectValue = SGF.emitSubstToOrigValue(loc, objectValue, abstraction,
                                                 resultObjectType);
        auto some = SGF.B.createEnum(loc, objectValue.forward(SGF),
                                     someDecl, resultTL.getLoweredType());
        SGF.Cleanups.emitBranchAndCleanups(scope.getExitDest(), loc, { some });
        return;
      }

      // Otherwise, make sure the value is in the context.
      if (!objectValue.isInContext() && hasAbstraction) {
        objectValue = SGF.emitSubstToOrigValue(loc, objectValue, abstraction,
                                               resultObjectType,
                                   SGFContext(&resultObjectTemp.getValue()));
      }
      if (!objectValue.isInContext()) {
        objectValue.forwardInto(SGF, loc, resultObjectBuffer);
      }
      SGF.B.createInjectEnumAddr(loc, resultBuffer, someDecl);
      SGF.Cleanups.emitBranchAndCleanups(scope.getExitDest(), loc);
    },
    // The failure path.
    [&] {
      auto noneDecl = SGF.getASTContext().getOptionalNoneDecl(optKind);

      // If we're not emitting into a temporary, just wrap up the result
      // in None and go to the continuation block.
      if (!resultObjectTemp) {
        auto none =
          SGF.B.createEnum(loc, nullptr, noneDecl, resultTL.getLoweredType());
        SGF.Cleanups.emitBranchAndCleanups(scope.getExitDest(), loc, { none });

      // Just construct the enum directly in the context.
//.........这里部分代码省略.........