LLVM  15.0.0git
Any.h
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1 //===- Any.h - Generic type erased holder of any type -----------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 ///
9 /// \file
10 /// This file provides Any, a non-template class modeled in the spirit of
11 /// std::any. The idea is to provide a type-safe replacement for C's void*.
12 /// It can hold a value of any copy-constructible copy-assignable type
13 ///
14 //===----------------------------------------------------------------------===//
15 
16 #ifndef LLVM_ADT_ANY_H
17 #define LLVM_ADT_ANY_H
18 
20 #include "llvm/Support/Compiler.h"
21 
22 #include <cassert>
23 #include <memory>
24 #include <type_traits>
25 
26 namespace llvm {
27 
29 
30  // The `Typeid<T>::Id` static data member below is a globally unique
31  // identifier for the type `T`. It is explicitly marked with default
32  // visibility so that when `-fvisibility=hidden` is used, the loader still
33  // merges duplicate definitions across DSO boundaries.
34  template <typename T> struct TypeId { static const char Id; };
35 
36  struct StorageBase {
37  virtual ~StorageBase() = default;
38  virtual std::unique_ptr<StorageBase> clone() const = 0;
39  virtual const void *id() const = 0;
40  };
41 
42  template <typename T> struct StorageImpl : public StorageBase {
43  explicit StorageImpl(const T &Value) : Value(Value) {}
44 
45  explicit StorageImpl(T &&Value) : Value(std::move(Value)) {}
46 
47  std::unique_ptr<StorageBase> clone() const override {
48  return std::make_unique<StorageImpl<T>>(Value);
49  }
50 
51  const void *id() const override { return &TypeId<T>::Id; }
52 
53  T Value;
54 
55  private:
56  StorageImpl &operator=(const StorageImpl &Other) = delete;
57  StorageImpl(const StorageImpl &Other) = delete;
58  };
59 
60 public:
61  Any() = default;
62 
63  Any(const Any &Other)
64  : Storage(Other.Storage ? Other.Storage->clone() : nullptr) {}
65 
66  // When T is Any or T is not copy-constructible we need to explicitly disable
67  // the forwarding constructor so that the copy constructor gets selected
68  // instead.
69  template <typename T,
70  std::enable_if_t<
73  // We also disable this overload when an `Any` object can be
74  // converted to the parameter type because in that case,
75  // this constructor may combine with that conversion during
76  // overload resolution for determining copy
77  // constructibility, and then when we try to determine copy
78  // constructibility below we may infinitely recurse. This is
79  // being evaluated by the standards committee as a potential
80  // DR in `std::any` as well, but we're going ahead and
81  // adopting it to work-around usage of `Any` with types that
82  // need to be implicitly convertible from an `Any`.
84  std::is_copy_constructible<std::decay_t<T>>>::value,
85  int> = 0>
86  Any(T &&Value) {
87  Storage =
88  std::make_unique<StorageImpl<std::decay_t<T>>>(std::forward<T>(Value));
89  }
90 
91  Any(Any &&Other) : Storage(std::move(Other.Storage)) {}
92 
93  Any &swap(Any &Other) {
94  std::swap(Storage, Other.Storage);
95  return *this;
96  }
97 
98  Any &operator=(Any Other) {
99  Storage = std::move(Other.Storage);
100  return *this;
101  }
102 
103  bool hasValue() const { return !!Storage; }
104 
105  void reset() { Storage.reset(); }
106 
107 private:
108  template <class T> friend T any_cast(const Any &Value);
109  template <class T> friend T any_cast(Any &Value);
110  template <class T> friend T any_cast(Any &&Value);
111  template <class T> friend const T *any_cast(const Any *Value);
112  template <class T> friend T *any_cast(Any *Value);
113  template <typename T> friend bool any_isa(const Any &Value);
114 
115  std::unique_ptr<StorageBase> Storage;
116 };
117 
118 template <typename T> const char Any::TypeId<T>::Id = 0;
119 
120 
121 template <typename T> bool any_isa(const Any &Value) {
122  if (!Value.Storage)
123  return false;
124  return Value.Storage->id() == &Any::TypeId<remove_cvref_t<T>>::Id;
125 }
126 
127 template <class T> T any_cast(const Any &Value) {
128  return static_cast<T>(*any_cast<remove_cvref_t<T>>(&Value));
129 }
130 
131 template <class T> T any_cast(Any &Value) {
132  return static_cast<T>(*any_cast<remove_cvref_t<T>>(&Value));
133 }
134 
135 template <class T> T any_cast(Any &&Value) {
136  return static_cast<T>(std::move(*any_cast<remove_cvref_t<T>>(&Value)));
137 }
138 
139 template <class T> const T *any_cast(const Any *Value) {
140  using U = remove_cvref_t<T>;
141  assert(Value && any_isa<T>(*Value) && "Bad any cast!");
142  if (!Value || !any_isa<U>(*Value))
143  return nullptr;
144  return &static_cast<Any::StorageImpl<U> &>(*Value->Storage).Value;
145 }
146 
147 template <class T> T *any_cast(Any *Value) {
148  using U = std::decay_t<T>;
149  assert(Value && any_isa<U>(*Value) && "Bad any cast!");
150  if (!Value || !any_isa<U>(*Value))
151  return nullptr;
152  return &static_cast<Any::StorageImpl<U> &>(*Value->Storage).Value;
153 }
154 
155 } // end namespace llvm
156 
157 #endif // LLVM_ADT_ANY_H
llvm::Any::hasValue
bool hasValue() const
Definition: Any.h:103
llvm
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:17
llvm::Any::Any
Any(T &&Value)
Definition: Any.h:86
llvm::Any::Any
Any(Any &&Other)
Definition: Any.h:91
T
#define T
Definition: Mips16ISelLowering.cpp:341
llvm::conjunction
Definition: STLForwardCompat.h:33
STLForwardCompat.h
llvm::Any::Any
Any(const Any &Other)
Definition: Any.h:63
LLVM_EXTERNAL_VISIBILITY
#define LLVM_EXTERNAL_VISIBILITY
Definition: Compiler.h:126
move
compiles ldr LCPI1_0 ldr ldr mov lsr tst moveq r1 ldr LCPI1_1 and r0 bx lr It would be better to do something like to fold the shift into the conditional move
Definition: README.txt:546
llvm::Any::operator=
Any & operator=(Any Other)
Definition: Any.h:98
assert
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
llvm::move
OutputIt move(R &&Range, OutputIt Out)
Provide wrappers to std::move which take ranges instead of having to pass begin/end explicitly.
Definition: STLExtras.h:1663
std::swap
void swap(llvm::BitVector &LHS, llvm::BitVector &RHS)
Implement std::swap in terms of BitVector swap.
Definition: BitVector.h:853
llvm::any_isa
bool any_isa(const Any &Value)
Definition: Any.h:121
remove_cvref_t
llvm::Any::reset
void reset()
Definition: Any.h:105
Compiler.h
llvm::Any
Definition: Any.h:28
std
Definition: BitVector.h:851
llvm::any_cast
T any_cast(const Any &Value)
Definition: Any.h:127
llvm::TargetStackID::Value
Value
Definition: TargetFrameLowering.h:27
llvm::Any::swap
Any & swap(Any &Other)
Definition: Any.h:93
llvm::negation
Definition: STLForwardCompat.h:29
llvm::AMDGPU::VGPRIndexMode::Id
Id
Definition: SIDefines.h:235
llvm::Value
LLVM Value Representation.
Definition: Value.h:74
Other
Optional< std::vector< StOtherPiece > > Other
Definition: ELFYAML.cpp:1225