//===- 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