1 //===- ARCRuntimeEntryPoints.h - ObjC ARC Optimization ----------*- 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 contains a class ARCRuntimeEntryPoints for use in
11 /// creating/managing references to entry points to the arc objective c runtime.
12 ///
13 /// WARNING: This file knows about certain library functions. It recognizes them
14 /// by name, and hardwires knowledge of their semantics.
15 ///
16 /// WARNING: This file knows about how certain Objective-C library functions are
17 /// used. Naive LLVM IR transformations which would otherwise be
18 /// behavior-preserving may break these assumptions.
19 //
20 //===----------------------------------------------------------------------===//
21 
22 #ifndef LLVM_LIB_TRANSFORMS_OBJCARC_ARCRUNTIMEENTRYPOINTS_H
23 #define LLVM_LIB_TRANSFORMS_OBJCARC_ARCRUNTIMEENTRYPOINTS_H
24 
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/IR/Attributes.h"
27 #include "llvm/IR/DerivedTypes.h"
28 #include "llvm/IR/Intrinsics.h"
29 #include "llvm/IR/Module.h"
30 #include "llvm/IR/Type.h"
31 #include "llvm/Support/ErrorHandling.h"
32 #include <cassert>
33 
34 namespace llvm {
35 
36 class Function;
37 class LLVMContext;
38 
39 namespace objcarc {
40 
41 enum class ARCRuntimeEntryPointKind {
42   AutoreleaseRV,
43   Release,
44   Retain,
45   RetainBlock,
46   Autorelease,
47   StoreStrong,
48   RetainRV,
49   RetainAutorelease,
50   RetainAutoreleaseRV,
51 };
52 
53 /// Declarations for ObjC runtime functions and constants. These are initialized
54 /// lazily to avoid cluttering up the Module with unused declarations.
55 class ARCRuntimeEntryPoints {
56 public:
57   ARCRuntimeEntryPoints() = default;
58 
59   void init(Module *M) {
60     TheModule = M;
61     AutoreleaseRV = nullptr;
62     Release = nullptr;
63     Retain = nullptr;
64     RetainBlock = nullptr;
65     Autorelease = nullptr;
66     StoreStrong = nullptr;
67     RetainRV = nullptr;
68     RetainAutorelease = nullptr;
69     RetainAutoreleaseRV = nullptr;
70   }
71 
72   Function *get(ARCRuntimeEntryPointKind kind) {
73     assert(TheModule != nullptr && "Not initialized.");
74 
75     switch (kind) {
76     case ARCRuntimeEntryPointKind::AutoreleaseRV:
77       return getIntrinsicEntryPoint(AutoreleaseRV,
78                                     Intrinsic::objc_autoreleaseReturnValue);
79     case ARCRuntimeEntryPointKind::Release:
80       return getIntrinsicEntryPoint(Release, Intrinsic::objc_release);
81     case ARCRuntimeEntryPointKind::Retain:
82       return getIntrinsicEntryPoint(Retain, Intrinsic::objc_retain);
83     case ARCRuntimeEntryPointKind::RetainBlock:
84       return getIntrinsicEntryPoint(RetainBlock, Intrinsic::objc_retainBlock);
85     case ARCRuntimeEntryPointKind::Autorelease:
86       return getIntrinsicEntryPoint(Autorelease, Intrinsic::objc_autorelease);
87     case ARCRuntimeEntryPointKind::StoreStrong:
88       return getIntrinsicEntryPoint(StoreStrong, Intrinsic::objc_storeStrong);
89     case ARCRuntimeEntryPointKind::RetainRV:
90       return getIntrinsicEntryPoint(RetainRV,
91                                 Intrinsic::objc_retainAutoreleasedReturnValue);
92     case ARCRuntimeEntryPointKind::RetainAutorelease:
93       return getIntrinsicEntryPoint(RetainAutorelease,
94                                     Intrinsic::objc_retainAutorelease);
95     case ARCRuntimeEntryPointKind::RetainAutoreleaseRV:
96       return getIntrinsicEntryPoint(RetainAutoreleaseRV,
97                                 Intrinsic::objc_retainAutoreleaseReturnValue);
98     }
99 
100     llvm_unreachable("Switch should be a covered switch.");
101   }
102 
103 private:
104   /// Cached reference to the module which we will insert declarations into.
105   Module *TheModule = nullptr;
106 
107   /// Declaration for ObjC runtime function objc_autoreleaseReturnValue.
108   Function *AutoreleaseRV = nullptr;
109 
110   /// Declaration for ObjC runtime function objc_release.
111   Function *Release = nullptr;
112 
113   /// Declaration for ObjC runtime function objc_retain.
114   Function *Retain = nullptr;
115 
116   /// Declaration for ObjC runtime function objc_retainBlock.
117   Function *RetainBlock = nullptr;
118 
119   /// Declaration for ObjC runtime function objc_autorelease.
120   Function *Autorelease = nullptr;
121 
122   /// Declaration for objc_storeStrong().
123   Function *StoreStrong = nullptr;
124 
125   /// Declaration for objc_retainAutoreleasedReturnValue().
126   Function *RetainRV = nullptr;
127 
128   /// Declaration for objc_retainAutorelease().
129   Function *RetainAutorelease = nullptr;
130 
131   /// Declaration for objc_retainAutoreleaseReturnValue().
132   Function *RetainAutoreleaseRV = nullptr;
133 
134   Function *getIntrinsicEntryPoint(Function *&Decl, Intrinsic::ID IntID) {
135     if (Decl)
136       return Decl;
137 
138     return Decl = Intrinsic::getDeclaration(TheModule, IntID);
139   }
140 };
141 
142 } // end namespace objcarc
143 
144 } // end namespace llvm
145 
146 #endif // LLVM_LIB_TRANSFORMS_OBJCARC_ARCRUNTIMEENTRYPOINTS_H
147