carbon-lang/toolchain/sem_ir/generic.h

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

#ifndef CARBON_TOOLCHAIN_SEM_IR_GENERIC_H_
#define CARBON_TOOLCHAIN_SEM_IR_GENERIC_H_

#include "common/set.h"
#include "toolchain/sem_ir/ids.h"

namespace Carbon::SemIR {

// Information for a generic entity, such as a generic class, a generic
// interface, or generic function.
//
// Note that this includes both checked generics and template generics.
struct Generic : public Printable<Generic> {
  auto Print(llvm::raw_ostream& out) const -> void {
    out << "{decl: " << decl_id << ", bindings: " << bindings_id << "}";
  }

  // The following members always have values, and do not change throughout the
  // lifetime of the generic.

  // The first declaration of the generic entity.
  InstId decl_id;
  // A block containing the IDs of compile time bindings in this generic scope.
  // The index in this block will match the `bind_index` in the name binding
  // instruction's `BindNameInfo`.
  InstBlockId bindings_id;
};

// An instance of a generic entity, such as an instance of a generic function.
// For each construct that depends on a compile-time parameter in the generic
// entity, this contains the corresponding non-generic value. This includes
// values for the compile-time parameters themselves.
struct GenericInstance : Printable<GenericInstance> {
  auto Print(llvm::raw_ostream& out) const -> void {
    out << "{generic: " << generic_id << ", args: " << args_id << "}";
  }

  // The generic that this is an instance of.
  GenericId generic_id;
  // Argument values, corresponding to the bindings in `Generic::bindings_id`.
  InstBlockId args_id;
};

// Provides storage for deduplicated instances of generics.
class GenericInstanceStore : public Yaml::Printable<GenericInstanceStore> {
 public:
  // Adds a new generic instance, or gets the existing generic instance for a
  // specified generic and argument list. Returns the ID of the generic
  // instance. The argument IDs must be for instructions in the constant block,
  // and must be a canonical instruction block ID.
  auto GetOrAdd(GenericId generic_id, InstBlockId args_id) -> GenericInstanceId;

  // Gets the specified generic instance.
  auto Get(GenericInstanceId instance_id) const -> const GenericInstance& {
    return generic_instances_.Get(instance_id);
  }

  // Gets the specified generic instance.
  auto Get(GenericInstanceId instance_id) -> GenericInstance& {
    return generic_instances_.Get(instance_id);
  }

  // These are to support printable structures, and are not guaranteed.
  auto OutputYaml() const -> Yaml::OutputMapping {
    return generic_instances_.OutputYaml();
  }

 private:
  // Context for hashing keys.
  class KeyContext;

  ValueStore<GenericInstanceId> generic_instances_;
  Carbon::Set<GenericInstanceId, 0, KeyContext> lookup_table_;
};

}  // namespace Carbon::SemIR

#endif  // CARBON_TOOLCHAIN_SEM_IR_GENERIC_H_