swift-mirror/include/swift/AST/LifetimeDependence.h

//===--- LifetimeDependence.h ---------------------------------*- C++ -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2024 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file defines types and utilities related to Lifetime Dependence
//
//===----------------------------------------------------------------------===//

#ifndef SWIFT_AST_LIFETIMEDEPENDENCE_H
#define SWIFT_AST_LIFETIMEDEPENDENCE_H

#include "swift/AST/DeclContext.h"
#include "swift/AST/Identifier.h"
#include "swift/AST/IndexSubset.h"
#include "swift/AST/Ownership.h"
#include "swift/Basic/Debug.h"
#include "swift/Basic/OptionSet.h"
#include "swift/Basic/SourceLoc.h"

#include "llvm/ADT/ArrayRef.h"

namespace swift {

class AbstractFunctionDecl;
class FunctionTypeRepr;
class LifetimeDependentTypeRepr;
class SILParameterInfo;
class SILResultInfo;

enum class ParsedLifetimeDependenceKind : uint8_t {
  Default = 0,
  Scope,
  Inherit // Only used with deserialized decls
};

enum class LifetimeDependenceKind : uint8_t { Inherit = 0, Scope };

enum class LifetimeEntryKind { Named, Ordered, Self, Immortal };

class LifetimeEntry {
private:
  SourceLoc loc;
  LifetimeEntryKind lifetimeEntryKind;
  ParsedLifetimeDependenceKind parsedLifetimeDependenceKind;
  union Value {
    struct {
      Identifier name;
    } Named;
    struct {
      unsigned index;
    } Ordered;
    struct {
    } self;
    Value(Identifier name) : Named({name}) {}
    Value(unsigned index) : Ordered({index}) {}
    Value() {}
  } value;

  LifetimeEntry(SourceLoc loc, LifetimeEntryKind lifetimeEntryKind,
                ParsedLifetimeDependenceKind parsedLifetimeDependenceKind,
                Value value)
      : loc(loc), lifetimeEntryKind(lifetimeEntryKind),
        parsedLifetimeDependenceKind(parsedLifetimeDependenceKind),
        value(value) {}

public:
  static LifetimeEntry
  getNamedLifetimeEntry(SourceLoc loc, Identifier name,
                        ParsedLifetimeDependenceKind kind =
                            ParsedLifetimeDependenceKind::Default) {
    return {loc, LifetimeEntryKind::Named, kind, name};
  }

  static LifetimeEntry getImmortalLifetimeEntry(SourceLoc loc) {
    return {loc, LifetimeEntryKind::Immortal, {}, {}};
  }

  static LifetimeEntry
  getOrderedLifetimeEntry(SourceLoc loc, unsigned index,
                          ParsedLifetimeDependenceKind kind =
                              ParsedLifetimeDependenceKind::Default) {
    return {loc, LifetimeEntryKind::Ordered, kind, index};
  }

  static LifetimeEntry
  getSelfLifetimeEntry(SourceLoc loc,
                       ParsedLifetimeDependenceKind kind =
                           ParsedLifetimeDependenceKind::Default) {
    return {loc, LifetimeEntryKind::Self, kind, {}};
  }

  SourceLoc getLoc() const { return loc; }

  LifetimeEntryKind getLifetimeEntryKind() const { return lifetimeEntryKind; }

  ParsedLifetimeDependenceKind getParsedLifetimeDependenceKind() const {
    return parsedLifetimeDependenceKind;
  }

  Identifier getName() const {
    assert(lifetimeEntryKind == LifetimeEntryKind::Named);
    return value.Named.name;
  }

  unsigned getIndex() const {
    assert(lifetimeEntryKind == LifetimeEntryKind::Ordered);
    return value.Ordered.index;
  }

  std::string getParamString() const {
    switch (lifetimeEntryKind) {
    case LifetimeEntryKind::Named:
      return value.Named.name.str().str();
    case LifetimeEntryKind::Self:
      return "self";
    case LifetimeEntryKind::Ordered:
      return std::to_string(value.Ordered.index);
    case LifetimeEntryKind::Immortal:
      return "immortal";
    }
    llvm_unreachable("Invalid LifetimeEntryKind");
  }

  std::string getDependsOnString() const {
    switch (parsedLifetimeDependenceKind) {
    case ParsedLifetimeDependenceKind::Default:
      return "dependsOn(" + getParamString() + ")";
    case ParsedLifetimeDependenceKind::Scope:
      return "dependsOn(scoped " + getParamString() + ")";
    case ParsedLifetimeDependenceKind::Inherit:
      return "dependsOn(inherited " + getParamString() + ")";
    }
    llvm_unreachable("Invalid LifetimeEntry::ParsedLifetimeDependenceKind");
  }
};

class LifetimeDependenceInfo {
  IndexSubset *inheritLifetimeParamIndices;
  IndexSubset *scopeLifetimeParamIndices;
  unsigned targetIndex;
  bool immortal;

  static LifetimeDependenceInfo getForIndex(AbstractFunctionDecl *afd,
                                            unsigned targetIndex,
                                            unsigned sourceIndex,
                                            LifetimeDependenceKind kind);

  /// Builds LifetimeDependenceInfo from @lifetime attribute
  static std::optional<ArrayRef<LifetimeDependenceInfo>>
  fromLifetimeAttribute(AbstractFunctionDecl *afd);

  /// Builds LifetimeDependenceInfo from dependsOn type modifier
  static std::optional<LifetimeDependenceInfo>
  fromDependsOn(AbstractFunctionDecl *afd, TypeRepr *targetRepr,
                Type targetType, unsigned targetIndex);

  /// Infer LifetimeDependenceInfo on result
  static std::optional<LifetimeDependenceInfo> infer(AbstractFunctionDecl *afd);

  /// Infer LifetimeDependenceInfo on setter
  static std::optional<LifetimeDependenceInfo>
  inferSetter(AbstractFunctionDecl *afd);

  /// Infer LifetimeDependenceInfo on mutating self
  static std::optional<LifetimeDependenceInfo>
  inferMutatingSelf(AbstractFunctionDecl *afd);

  /// Builds LifetimeDependenceInfo from SIL function type
  static std::optional<LifetimeDependenceInfo>
  fromDependsOn(LifetimeDependentTypeRepr *lifetimeDependentRepr,
                unsigned targetIndex, ArrayRef<SILParameterInfo> params,
                DeclContext *dc);

public:
  LifetimeDependenceInfo(IndexSubset *inheritLifetimeParamIndices,
                         IndexSubset *scopeLifetimeParamIndices,
                         unsigned targetIndex, bool isImmortal)
      : inheritLifetimeParamIndices(inheritLifetimeParamIndices),
        scopeLifetimeParamIndices(scopeLifetimeParamIndices),
        targetIndex(targetIndex), immortal(isImmortal) {
    assert(isImmortal || inheritLifetimeParamIndices ||
           scopeLifetimeParamIndices);
    assert(!inheritLifetimeParamIndices ||
           !inheritLifetimeParamIndices->isEmpty());
    assert(!scopeLifetimeParamIndices || !scopeLifetimeParamIndices->isEmpty());
  }

  operator bool() const { return !empty(); }

  bool empty() const {
    return !immortal && inheritLifetimeParamIndices == nullptr &&
           scopeLifetimeParamIndices == nullptr;
  }

  bool isImmortal() const { return immortal; }

  unsigned getTargetIndex() const { return targetIndex; }

  bool hasInheritLifetimeParamIndices() const {
    return inheritLifetimeParamIndices != nullptr;
  }
  bool hasScopeLifetimeParamIndices() const {
    return scopeLifetimeParamIndices != nullptr;
  }

  IndexSubset *getInheritIndices() const { return inheritLifetimeParamIndices; }

  IndexSubset *getScopeIndices() const { return scopeLifetimeParamIndices; }

  bool checkInherit(int index) const {
    return inheritLifetimeParamIndices
      && inheritLifetimeParamIndices->contains(index);
  }

  bool checkScope(int index) const {
    return scopeLifetimeParamIndices
      && scopeLifetimeParamIndices->contains(index);
  }

  std::string getString() const;
  void Profile(llvm::FoldingSetNodeID &ID) const;
  void getConcatenatedData(SmallVectorImpl<bool> &concatenatedData) const;

  /// Builds LifetimeDependenceInfo from a swift decl, either from the explicit
  /// lifetime dependence specifiers or by inference based on types and
  /// ownership modifiers.
  static std::optional<ArrayRef<LifetimeDependenceInfo>>
  get(AbstractFunctionDecl *decl);

  /// Builds LifetimeDependenceInfo from SIL
  static std::optional<llvm::ArrayRef<LifetimeDependenceInfo>>
  get(FunctionTypeRepr *funcRepr, ArrayRef<SILParameterInfo> params,
      ArrayRef<SILResultInfo> results, DeclContext *dc);

  bool operator==(const LifetimeDependenceInfo &other) const {
    return this->isImmortal() == other.isImmortal() &&
           this->getTargetIndex() == other.getTargetIndex() &&
           this->getInheritIndices() == other.getInheritIndices() &&
           this->getScopeIndices() == other.getScopeIndices();
  }

  bool operator!=(const LifetimeDependenceInfo &other) const {
    return this->isImmortal() != other.isImmortal() &&
           this->getTargetIndex() != other.getTargetIndex() &&
           this->getInheritIndices() != other.getInheritIndices() &&
           this->getScopeIndices() != other.getScopeIndices();
  }
};

std::optional<LifetimeDependenceInfo>
getLifetimeDependenceFor(ArrayRef<LifetimeDependenceInfo> lifetimeDependencies,
                         unsigned index);
} // namespace swift

#endif