ESITypes.cpp

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//===- ESITypes.cpp - ESI types code defs -----------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Definitions for esi data types. Anything which doesn't have to be public
// should go in here.
//
//===----------------------------------------------------------------------===//
 
#include "circt/Dialect/ESI/ESITypes.h"
#include "circt/Dialect/HW/HWTypes.h"
#include "mlir/IR/Attributes.h"
#include "mlir/IR/DialectImplementation.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/TypeSwitch.h"
 
using namespace circt;
using namespace circt::esi;
 
AnyType AnyType::get(MLIRContext *context) { return Base::get(context); }
 
LogicalResult
WindowType::verify(llvm::function_ref<InFlightDiagnostic()> emitError,
                   StringAttr name, Type into,
                   ArrayRef<WindowFrameType> frames) {
  auto structInto = hw::type_dyn_cast<hw::StructType>(into);
  if (!structInto)
    return emitError() << "only windows into structs are currently supported";
 
  auto fields = structInto.getElements();
  for (auto frame : frames) {
    // Efficiently look up fields in the frame.
    DenseMap<StringAttr, WindowFieldType> frameFields;
    for (auto field : frame.getMembers())
      frameFields[field.getFieldName()] = field;
 
    // Iterate through the list of struct fields until we've encountered all the
    // fields listed in the frame.
    while (!fields.empty() && !frameFields.empty()) {
      hw::StructType::FieldInfo field = fields.front();
      fields = fields.drop_front();
      auto f = frameFields.find(field.name);
 
      // If a field in the struct isn't listed, it's being omitted from the
      // window so we just skip it.
      if (f == frameFields.end())
        continue;
 
      // If 'numItems' is specified, gotta run more checks.
      uint64_t numItems = f->getSecond().getNumItems();
      if (numItems > 0) {
        auto arrField = hw::type_dyn_cast<hw::ArrayType>(field.type);
        if (!arrField)
          return emitError() << "cannot specify num items on non-array field "
                             << field.name;
        if (numItems > arrField.getNumElements())
          return emitError() << "num items is larger than array size in field "
                             << field.name;
        if (frame.getMembers().size() != 1)
          return emitError()
                 << "array with size specified must be in their own frame (in "
                 << field.name << ")";
      }
      frameFields.erase(f);
    }
 
    // If there is anything left in the frame list, it either refers to a
    // non-existant field or said frame was already consumed by a previous
    // frame.
    if (!frameFields.empty())
      return emitError() << "invalid field name: "
                         << frameFields.begin()->getSecond().getFieldName();
  }
  return success();
}
 
hw::UnionType WindowType::getLoweredType() const {
  // Assemble a fast lookup of struct fields to types.
  auto into = hw::type_cast<hw::StructType>(getInto());
  SmallDenseMap<StringAttr, Type> intoFields;
  for (hw::StructType::FieldInfo field : into.getElements())
    intoFields[field.name] = field.type;
 
  // Build the union, frame by frame
  SmallVector<hw::UnionType::FieldInfo, 4> unionFields;
  for (WindowFrameType frame : getFrames()) {
 
    // ... field by field.
    SmallVector<hw::StructType::FieldInfo, 4> fields;
    for (WindowFieldType field : frame.getMembers()) {
      auto fieldTypeIter = intoFields.find(field.getFieldName());
      assert(fieldTypeIter != intoFields.end());
 
      // If the number of items isn't specified, just use the type.
      if (field.getNumItems() == 0) {
        fields.push_back({field.getFieldName(), fieldTypeIter->getSecond()});
      } else {
        // If the number of items is specified, we can assume that it's an array
        // type.
        auto array = hw::type_cast<hw::ArrayType>(fieldTypeIter->getSecond());
        assert(fields.empty()); // Checked by the validator.
 
        // The first union entry should be an array of length numItems.
        fields.push_back(
            {field.getFieldName(),
             hw::ArrayType::get(array.getElementType(), field.getNumItems())});
        unionFields.push_back(
            {frame.getName(), hw::StructType::get(getContext(), fields), 0});
        fields.clear();
 
        // If the array size is not a multiple of numItems, we need another
        // frame for the left overs.
        size_t leftOver = array.getNumElements() % field.getNumItems();
        if (leftOver) {
          fields.push_back(
              {field.getFieldName(),
               hw::ArrayType::get(array.getElementType(), leftOver)});
 
          unionFields.push_back(
              {StringAttr::get(getContext(),
                               Twine(frame.getName().getValue(), "_leftOver")),
               hw::StructType::get(getContext(), fields), 0});
          fields.clear();
        }
      }
    }
 
    if (!fields.empty())
      unionFields.push_back(
          {frame.getName(), hw::StructType::get(getContext(), fields), 0});
  }
 
  return hw::UnionType::get(getContext(), unionFields);
}
 
namespace mlir {
template <>
struct FieldParser<::BundledChannel, ::BundledChannel> {
  static FailureOr<::BundledChannel> parse(AsmParser &p) {
    ChannelType type;
    std::string name;
    if (p.parseType(type))
      return failure();
    auto dir = FieldParser<::ChannelDirection>::parse(p);
    if (failed(dir))
      return failure();
    if (p.parseKeywordOrString(&name))
      return failure();
    return BundledChannel{StringAttr::get(p.getContext(), name), *dir, type};
  }
};
} // namespace mlir
 
namespace llvm {
inline ::llvm::raw_ostream &operator<<(::llvm::raw_ostream &p,
                                       ::BundledChannel channel) {
  p << channel.type << " " << channel.direction << " " << channel.name;
  return p;
}
} // namespace llvm
 
ChannelBundleType ChannelBundleType::getReversed() const {
  SmallVector<BundledChannel, 4> reversed;
  for (auto channel : getChannels())
    reversed.push_back({channel.name, flip(channel.direction), channel.type});
  return ChannelBundleType::get(getContext(), reversed, getResettable());
}
 
#define GET_TYPEDEF_CLASSES
#include "circt/Dialect/ESI/ESITypes.cpp.inc"
 
void ESIDialect::registerTypes() {
  addTypes<
#define GET_TYPEDEF_LIST
#include "circt/Dialect/ESI/ESITypes.cpp.inc"
      >();
}
 
mlir::Type circt::esi::innerType(mlir::Type type) {
  circt::esi::ChannelType chan =
      type.dyn_cast_or_null<circt::esi::ChannelType>();
  if (chan) // Unwrap the channel if it's a channel.
    type = chan.getInner();
 
  return type;
}