Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===- ValueMap.h - Safe map from Values to data ----------------*- 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

//

//===----------------------------------------------------------------------===//

//

// This file defines the ValueMap class.  ValueMap maps Value* or any subclass

// to an arbitrary other type.  It provides the DenseMap interface but updates

// itself to remain safe when keys are RAUWed or deleted.  By default, when a

// key is RAUWed from V1 to V2, the old mapping V1->target is removed, and a new

// mapping V2->target is added.  If V2 already existed, its old target is

// overwritten.  When a key is deleted, its mapping is removed.

//

// You can override a ValueMap's Config parameter to control exactly what

// happens on RAUW and destruction and to get called back on each event.  It's

// legal to call back into the ValueMap from a Config's callbacks.  Config

// parameters should inherit from ValueMapConfig<KeyT> to get default

// implementations of all the methods ValueMap uses.  See ValueMapConfig for

// documentation of the functions you can override.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_IR_VALUEMAP_H

#define LLVM_IR_VALUEMAP_H

#include "llvm/ADT/DenseMap.h"

#include "llvm/ADT/DenseMapInfo.h"

#include "llvm/IR/TrackingMDRef.h"

#include "llvm/IR/ValueHandle.h"

#include "llvm/Support/Casting.h"

#include "llvm/Support/Mutex.h"

#include <algorithm>

#include <cassert>

#include <cstddef>

#include <iterator>

#include <mutex>

#include <optional>

#include <type_traits>

#include <utility>

namespace llvm {

template<typename KeyT, typename ValueT, typename Config>

class ValueMapCallbackVH;

template<typename DenseMapT, typename KeyT>

class ValueMapIterator;

template<typename DenseMapT, typename KeyT>

class ValueMapConstIterator;

/// This class defines the default behavior for configurable aspects of

/// ValueMap<>.  User Configs should inherit from this class to be as compatible

/// as possible with future versions of ValueMap.

template<typename KeyT, typename MutexT = sys::Mutex>

struct ValueMapConfig {

  using mutex_type = MutexT;

  /// If FollowRAUW is true, the ValueMap will update mappings on RAUW. If it's

  /// false, the ValueMap will leave the original mapping in place.

  enum { FollowRAUW = true };

  // All methods will be called with a first argument of type ExtraData.  The

  // default implementations in this class take a templated first argument so

  // that users' subclasses can use any type they want without having to

  // override all the defaults.

  struct ExtraData {};

  template<typename ExtraDataT>

  static void onRAUW(const ExtraDataT & /*Data*/, KeyT /*Old*/, KeyT /*New*/) {}

  template<typename ExtraDataT>

  static void onDelete(const ExtraDataT &/*Data*/, KeyT /*Old*/) {}

  /// Returns a mutex that should be acquired around any changes to the map.

  /// This is only acquired from the CallbackVH (and held around calls to onRAUW

  /// and onDelete) and not inside other ValueMap methods.  NULL means that no

  /// mutex is necessary.

  template<typename ExtraDataT>

  static mutex_type *getMutex(const ExtraDataT &/*Data*/) { return nullptr; }

};

/// See the file comment.

template<typename KeyT, typename ValueT, typename Config =ValueMapConfig<KeyT>>

class ValueMap {

  friend class ValueMapCallbackVH<KeyT, ValueT, Config>;

  using ValueMapCVH = ValueMapCallbackVH<KeyT, ValueT, Config>;

  using MapT = DenseMap<ValueMapCVH, ValueT, DenseMapInfo<ValueMapCVH>>;

  using MDMapT = DenseMap<const Metadata *, TrackingMDRef>;

  using ExtraData = typename Config::ExtraData;

  MapT Map;

  std::optional<MDMapT> MDMap;

  ExtraData Data;

public:

  using key_type = KeyT;

  using mapped_type = ValueT;

  using value_type = std::pair<KeyT, ValueT>;

  using size_type = unsigned;

  explicit ValueMap(unsigned NumInitBuckets = 64)

      : Map(NumInitBuckets), Data() {}

  explicit ValueMap(const ExtraData &Data, unsigned NumInitBuckets = 64)

      : Map(NumInitBuckets), Data(Data) {}

  // ValueMap can't be copied nor moved, because the callbacks store pointer to

  // it.

  ValueMap(const ValueMap &) = delete;

  ValueMap(ValueMap &&) = delete;

  ValueMap &operator=(const ValueMap &) = delete;

  ValueMap &operator=(ValueMap &&) = delete;

  bool hasMD() const { return bool(MDMap); }

  MDMapT &MD() {

    if (!MDMap)

      MDMap.emplace();

    return *MDMap;

  }

  std::optional<MDMapT> &getMDMap() { return MDMap; }

  /// Get the mapped metadata, if it's in the map.

  std::optional<Metadata *> getMappedMD(const Metadata *MD) const {

    if (!MDMap)

      return std::nullopt;

    auto Where = MDMap->find(MD);

    if (Where == MDMap->end())

      return std::nullopt;

    return Where->second.get();

  }

  using iterator = ValueMapIterator<MapT, KeyT>;

  using const_iterator = ValueMapConstIterator<MapT, KeyT>;

  inline iterator begin() { return iterator(Map.begin()); }

  inline iterator end() { return iterator(Map.end()); }

  inline const_iterator begin() const { return const_iterator(Map.begin()); }

  inline const_iterator end() const { return const_iterator(Map.end()); }

  bool empty() const { return Map.empty(); }

  size_type size() const { return Map.size(); }

  /// Grow the map so that it has at least Size buckets. Does not shrink

  void reserve(size_t Size) { Map.reserve(Size); }

  void clear() {

    Map.clear();

    MDMap.reset();

  }

  /// Return 1 if the specified key is in the map, 0 otherwise.

  size_type count(const KeyT &Val) const {

    return Map.find_as(Val) == Map.end() ? 0 : 1;

  }

  iterator find(const KeyT &Val) {

    return iterator(Map.find_as(Val));

  }

  const_iterator find(const KeyT &Val) const {

    return const_iterator(Map.find_as(Val));

  }

  /// lookup - Return the entry for the specified key, or a default

  /// constructed value if no such entry exists.

  ValueT lookup(const KeyT &Val) const {

    typename MapT::const_iterator I = Map.find_as(Val);

    return I != Map.end() ? I->second : ValueT();

  }

  // Inserts key,value pair into the map if the key isn't already in the map.

  // If the key is already in the map, it returns false and doesn't update the

  // value.

  std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) {

    auto MapResult = Map.insert(std::make_pair(Wrap(KV.first), KV.second));

    return std::make_pair(iterator(MapResult.first), MapResult.second);

  }

  std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &&KV) {

    auto MapResult =

        Map.insert(std::make_pair(Wrap(KV.first), std::move(KV.second)));

    return std::make_pair(iterator(MapResult.first), MapResult.second);

  }

  /// insert - Range insertion of pairs.

  template<typename InputIt>

  void insert(InputIt I, InputIt E) {

    for (; I != E; ++I)

      insert(*I);

  }

  bool erase(const KeyT &Val) {

    typename MapT::iterator I = Map.find_as(Val);

    if (I == Map.end())

      return false;

    Map.erase(I);

    return true;

  }

  void erase(iterator I) {

    return Map.erase(I.base());

  }

  value_type& FindAndConstruct(const KeyT &Key) {

    return Map.FindAndConstruct(Wrap(Key));

  }

  ValueT &operator[](const KeyT &Key) {

    return Map[Wrap(Key)];

  }

  /// isPointerIntoBucketsArray - Return true if the specified pointer points

  /// somewhere into the ValueMap's array of buckets (i.e. either to a key or

  /// value in the ValueMap).

  bool isPointerIntoBucketsArray(const void *Ptr) const {

    return Map.isPointerIntoBucketsArray(Ptr);

  }

  /// getPointerIntoBucketsArray() - Return an opaque pointer into the buckets

  /// array.  In conjunction with the previous method, this can be used to

  /// determine whether an insertion caused the ValueMap to reallocate.

  const void *getPointerIntoBucketsArray() const {

    return Map.getPointerIntoBucketsArray();

  }

private:

  // Takes a key being looked up in the map and wraps it into a

  // ValueMapCallbackVH, the actual key type of the map.  We use a helper

  // function because ValueMapCVH is constructed with a second parameter.

  ValueMapCVH Wrap(KeyT key) const {

    // The only way the resulting CallbackVH could try to modify *this (making

    // the const_cast incorrect) is if it gets inserted into the map.  But then

    // this function must have been called from a non-const method, making the

    // const_cast ok.

    return ValueMapCVH(key, const_cast<ValueMap*>(this));

  }

};

// This CallbackVH updates its ValueMap when the contained Value changes,

// according to the user's preferences expressed through the Config object.

template <typename KeyT, typename ValueT, typename Config>

class ValueMapCallbackVH final : public CallbackVH {

  friend class ValueMap<KeyT, ValueT, Config>;

  friend struct DenseMapInfo<ValueMapCallbackVH>;

  using ValueMapT = ValueMap<KeyT, ValueT, Config>;

  using KeySansPointerT = std::remove_pointer_t<KeyT>;

  ValueMapT *Map;

  ValueMapCallbackVH(KeyT Key, ValueMapT *Map)

      : CallbackVH(const_cast<Value*>(static_cast<const Value*>(Key))),

        Map(Map) {}

  // Private constructor used to create empty/tombstone DenseMap keys.

  ValueMapCallbackVH(Value *V) : CallbackVH(V), Map(nullptr) {}

public:

  KeyT Unwrap() const { return cast_or_null<KeySansPointerT>(getValPtr()); }

  void deleted() override {

    // Make a copy that won't get changed even when *this is destroyed.

    ValueMapCallbackVH Copy(*this);

    typename Config::mutex_type *M = Config::getMutex(Copy.Map->Data);

    std::unique_lock<typename Config::mutex_type> Guard;

    if (M)

      Guard = std::unique_lock<typename Config::mutex_type>(*M);

    Config::onDelete(Copy.Map->Data, Copy.Unwrap());  // May destroy *this.

    Copy.Map->Map.erase(Copy);  // Definitely destroys *this.

  }

  void allUsesReplacedWith(Value *new_key) override {

    assert(isa<KeySansPointerT>(new_key) &&

           "Invalid RAUW on key of ValueMap<>");

    // Make a copy that won't get changed even when *this is destroyed.

    ValueMapCallbackVH Copy(*this);

    typename Config::mutex_type *M = Config::getMutex(Copy.Map->Data);

    std::unique_lock<typename Config::mutex_type> Guard;

    if (M)

      Guard = std::unique_lock<typename Config::mutex_type>(*M);

    KeyT typed_new_key = cast<KeySansPointerT>(new_key);

    // Can destroy *this:

    Config::onRAUW(Copy.Map->Data, Copy.Unwrap(), typed_new_key);

    if (Config::FollowRAUW) {

      typename ValueMapT::MapT::iterator I = Copy.Map->Map.find(Copy);

      // I could == Copy.Map->Map.end() if the onRAUW callback already

      // removed the old mapping.

      if (I != Copy.Map->Map.end()) {

        ValueT Target(std::move(I->second));

        Copy.Map->Map.erase(I);  // Definitely destroys *this.

        Copy.Map->insert(std::make_pair(typed_new_key, std::move(Target)));

      }

    }

  }

};

template<typename KeyT, typename ValueT, typename Config>

struct DenseMapInfo<ValueMapCallbackVH<KeyT, ValueT, Config>> {

  using VH = ValueMapCallbackVH<KeyT, ValueT, Config>;

  static inline VH getEmptyKey() {

    return VH(DenseMapInfo<Value *>::getEmptyKey());

  }

  static inline VH getTombstoneKey() {

    return VH(DenseMapInfo<Value *>::getTombstoneKey());

  }

  static unsigned getHashValue(const VH &Val) {

    return DenseMapInfo<KeyT>::getHashValue(Val.Unwrap());

  }

  static unsigned getHashValue(const KeyT &Val) {

    return DenseMapInfo<KeyT>::getHashValue(Val);

  }

  static bool isEqual(const VH &LHS, const VH &RHS) {

    return LHS == RHS;

  }

  static bool isEqual(const KeyT &LHS, const VH &RHS) {

    return LHS == RHS.getValPtr();

  }

};

template <typename DenseMapT, typename KeyT> class ValueMapIterator {

  using BaseT = typename DenseMapT::iterator;

  using ValueT = typename DenseMapT::mapped_type;

  BaseT I;

public:

  using iterator_category = std::forward_iterator_tag;

  using value_type = std::pair<KeyT, typename DenseMapT::mapped_type>;

  using difference_type = std::ptrdiff_t;

  using pointer = value_type *;

  using reference = value_type &;

  ValueMapIterator() : I() {}

  ValueMapIterator(BaseT I) : I(I) {}

  BaseT base() const { return I; }

  struct ValueTypeProxy {

    const KeyT first;

    ValueT& second;

    ValueTypeProxy *operator->() { return this; }

    operator std::pair<KeyT, ValueT>() const {

      return std::make_pair(first, second);

    }

  };

  ValueTypeProxy operator*() const {

    ValueTypeProxy Result = {I->first.Unwrap(), I->second};

    return Result;

  }

  ValueTypeProxy operator->() const {

    return operator*();

  }

  bool operator==(const ValueMapIterator &RHS) const {

    return I == RHS.I;

  }

  bool operator!=(const ValueMapIterator &RHS) const {

    return I != RHS.I;

  }

  inline ValueMapIterator& operator++() {  // Preincrement

    ++I;

    return *this;

  }

  ValueMapIterator operator++(int) {  // Postincrement

    ValueMapIterator tmp = *this; ++*this; return tmp;

  }

};

template <typename DenseMapT, typename KeyT> class ValueMapConstIterator {

  using BaseT = typename DenseMapT::const_iterator;

  using ValueT = typename DenseMapT::mapped_type;

  BaseT I;

public:

  using iterator_category = std::forward_iterator_tag;

  using value_type = std::pair<KeyT, typename DenseMapT::mapped_type>;

  using difference_type = std::ptrdiff_t;

  using pointer = value_type *;

  using reference = value_type &;

  ValueMapConstIterator() : I() {}

  ValueMapConstIterator(BaseT I) : I(I) {}

  ValueMapConstIterator(ValueMapIterator<DenseMapT, KeyT> Other)

    : I(Other.base()) {}

  BaseT base() const { return I; }

  struct ValueTypeProxy {

    const KeyT first;

    const ValueT& second;

    ValueTypeProxy *operator->() { return this; }

    operator std::pair<KeyT, ValueT>() const {

      return std::make_pair(first, second);

    }

  };

  ValueTypeProxy operator*() const {

    ValueTypeProxy Result = {I->first.Unwrap(), I->second};

    return Result;

  }

  ValueTypeProxy operator->() const {

    return operator*();

  }

  bool operator==(const ValueMapConstIterator &RHS) const {

    return I == RHS.I;

  }

  bool operator!=(const ValueMapConstIterator &RHS) const {

    return I != RHS.I;

  }

  inline ValueMapConstIterator& operator++() {  // Preincrement

    ++I;

    return *this;

  }

  ValueMapConstIterator operator++(int) {  // Postincrement

    ValueMapConstIterator tmp = *this; ++*this; return tmp;

  }

};

} // end namespace llvm

#endif // LLVM_IR_VALUEMAP_H