Location.h

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//===- Location.h - MLIR Location Classes -----------------------*- 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
//
//===----------------------------------------------------------------------===//
//
// These classes provide the ability to relate MLIR objects back to source
// location position information.
//
//===----------------------------------------------------------------------===//
 
#ifndef MLIR_IR_LOCATION_H
#define MLIR_IR_LOCATION_H
 
#include "mlir/IR/Attributes.h"
#include "llvm/Support/PointerLikeTypeTraits.h"
 
namespace mlir {
 
class Location;
class WalkResult;
 
//===----------------------------------------------------------------------===//
// LocationAttr
//===----------------------------------------------------------------------===//
 
/// Location objects represent source locations information in MLIR.
/// LocationAttr acts as the anchor for all Location based attributes.
class LocationAttr : public Attribute {
public:
  using Attribute::Attribute;
 
  /// Walk all of the locations nested under, and including, the current.
  WalkResult walk(function_ref<WalkResult(Location)> walkFn);
 
  /// Return an instance of the given location type if one is nested under the
  /// current location. Returns nullptr if one could not be found.
  template <typename T>
  T findInstanceOf() {
    T result = {};
    walk([&](auto loc) {
      if (auto typedLoc = llvm::dyn_cast<T>(loc)) {
        result = typedLoc;
        return WalkResult::interrupt();
      }
      return WalkResult::advance();
    });
    return result;
  }
 
  /// Methods for support type inquiry through isa, cast, and dyn_cast.
  static bool classof(Attribute attr);
};
 
//===----------------------------------------------------------------------===//
// Location
//===----------------------------------------------------------------------===//
 
/// This class defines the main interface for locations in MLIR and acts as a
/// non-nullable wrapper around a LocationAttr.
class Location {
public:
  Location(LocationAttr loc) : impl(loc) {
    assert(loc && "location should never be null.");
  }
  Location(const LocationAttr::ImplType *impl) : impl(impl) {
    assert(impl && "location should never be null.");
  }
 
  /// Return the context this location is uniqued in.
  MLIRContext *getContext() const { return impl.getContext(); }
 
  /// Access the impl location attribute.
  operator LocationAttr() const { return impl; }
  LocationAttr *operator->() const { return const_cast<LocationAttr *>(&impl); }
 
  /// Type casting utilities on the underlying location.
  template <typename U>
  bool isa() const {
    return llvm::isa<U>(*this);
  }
  template <typename U>
  U dyn_cast() const {
    return llvm::dyn_cast<U>(*this);
  }
  template <typename U>
  U cast() const {
    return llvm::cast<U>(*this);
  }
 
  /// Comparison operators.
  bool operator==(Location rhs) const { return impl == rhs.impl; }
  bool operator!=(Location rhs) const { return !(*this == rhs); }
 
  /// Print the location.
  void print(raw_ostream &os) const { impl.print(os); }
  void dump() const { impl.dump(); }
 
  friend ::llvm::hash_code hash_value(Location arg);
 
  /// Methods for supporting PointerLikeTypeTraits.
  const void *getAsOpaquePointer() const { return impl.getAsOpaquePointer(); }
  static Location getFromOpaquePointer(const void *pointer) {
    return LocationAttr(reinterpret_cast<const AttributeStorage *>(pointer));
  }
 
  /// Support llvm style casting.
  static bool classof(Attribute attr) { return llvm::isa<LocationAttr>(attr); }
 
protected:
  /// The internal backing location attribute.
  LocationAttr impl;
};
 
inline raw_ostream &operator<<(raw_ostream &os, const Location &loc) {
  loc.print(os);
  return os;
}
 
// Make Location hashable.
inline ::llvm::hash_code hash_value(Location arg) {
  return hash_value(arg.impl);
}
 
} // namespace mlir
 
//===----------------------------------------------------------------------===//
// Tablegen Attribute Declarations
//===----------------------------------------------------------------------===//
 
#define GET_ATTRDEF_CLASSES
#include "mlir/IR/BuiltinLocationAttributes.h.inc"
 
namespace mlir {
 
//===----------------------------------------------------------------------===//
// FusedLoc
//===----------------------------------------------------------------------===//
 
/// This class represents a fused location whose metadata is known to be an
/// instance of the given type.
template <typename MetadataT>
class FusedLocWith : public FusedLoc {
public:
  using FusedLoc::FusedLoc;
 
  /// Return the metadata associated with this fused location.
  MetadataT getMetadata() const {
    return FusedLoc::getMetadata().template cast<MetadataT>();
  }
 
  /// Support llvm style casting.
  static bool classof(Attribute attr) {
    auto fusedLoc = attr.dyn_cast<FusedLoc>();
    return fusedLoc && fusedLoc.getMetadata().isa_and_nonnull<MetadataT>();
  }
};
 
//===----------------------------------------------------------------------===//
// OpaqueLoc
//===----------------------------------------------------------------------===//
 
/// Returns an instance of opaque location which contains a given pointer to
/// an object. The corresponding MLIR location is set to UnknownLoc.
template <typename T>
inline OpaqueLoc OpaqueLoc::get(T underlyingLocation, MLIRContext *context) {
  return get(reinterpret_cast<uintptr_t>(underlyingLocation), TypeID::get<T>(),
             UnknownLoc::get(context));
}
 
//===----------------------------------------------------------------------===//
// SubElements
//===----------------------------------------------------------------------===//
 
/// Enable locations to be introspected as sub-elements.
template <>
struct AttrTypeSubElementHandler<Location> {
  static void walk(Location param, AttrTypeImmediateSubElementWalker &walker) {
    walker.walk(param);
  }
  static Location replace(Location param, AttrSubElementReplacements &attrRepls,
                          TypeSubElementReplacements &typeRepls) {
    return cast<LocationAttr>(attrRepls.take_front(1)[0]);
  }
};
 
} // namespace mlir
 
//===----------------------------------------------------------------------===//
// LLVM Utilities
//===----------------------------------------------------------------------===//
 
namespace llvm {
 
// Type hash just like pointers.
template <>
struct DenseMapInfo<mlir::Location> {
  static mlir::Location getEmptyKey() {
    auto *pointer = llvm::DenseMapInfo<void *>::getEmptyKey();
    return mlir::Location::getFromOpaquePointer(pointer);
  }
  static mlir::Location getTombstoneKey() {
    auto *pointer = llvm::DenseMapInfo<void *>::getTombstoneKey();
    return mlir::Location::getFromOpaquePointer(pointer);
  }
  static unsigned getHashValue(mlir::Location val) {
    return mlir::hash_value(val);
  }
  static bool isEqual(mlir::Location LHS, mlir::Location RHS) {
    return LHS == RHS;
  }
};
 
/// We align LocationStorage by 8, so allow LLVM to steal the low bits.
template <>
struct PointerLikeTypeTraits<mlir::Location> {
public:
  static inline void *getAsVoidPointer(mlir::Location I) {
    return const_cast<void *>(I.getAsOpaquePointer());
  }
  static inline mlir::Location getFromVoidPointer(void *P) {
    return mlir::Location::getFromOpaquePointer(P);
  }
  static constexpr int NumLowBitsAvailable =
      PointerLikeTypeTraits<mlir::Attribute>::NumLowBitsAvailable;
};
 
/// The constructors in mlir::Location ensure that the class is a non-nullable
/// wrapper around mlir::LocationAttr. Override default behavior and always
/// return true for isPresent().
template <>
struct ValueIsPresent<mlir::Location> {
  using UnwrappedType = mlir::Location;
  static inline bool isPresent(const mlir::Location &location) { return true; }
};
 
/// Add support for llvm style casts. We provide a cast between To and From if
/// From is mlir::Location or derives from it.
template <typename To, typename From>
struct CastInfo<To, From,
                std::enable_if_t<
                    std::is_same_v<mlir::Location, std::remove_const_t<From>> ||
                    std::is_base_of_v<mlir::Location, From>>>
    : DefaultDoCastIfPossible<To, From, CastInfo<To, From>> {
 
  static inline bool isPossible(mlir::Location location) {
    /// Return a constant true instead of a dynamic true when casting to self or
    /// up the hierarchy. Additionally, all casting info is deferred to the
    /// wrapped mlir::LocationAttr instance stored in mlir::Location.
    return std::is_same_v<To, std::remove_const_t<From>> ||
           isa<To>(static_cast<mlir::LocationAttr>(location));
  }
 
  static inline To castFailed() { return To(); }
 
  static inline To doCast(mlir::Location location) {
    return To(location->getImpl());
  }
};
 
} // namespace llvm
 
#endif