1 //===- ObjCARCInstKind.h - ARC instruction equivalence classes --*- 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 #ifndef LLVM_ANALYSIS_OBJCARCINSTKIND_H
10 #define LLVM_ANALYSIS_OBJCARCINSTKIND_H
11
12 #include "llvm/IR/Instructions.h"
13
14 namespace llvm {
15 namespace objcarc {
16
17 /// \enum ARCInstKind
18 ///
19 /// Equivalence classes of instructions in the ARC Model.
20 ///
21 /// Since we do not have "instructions" to represent ARC concepts in LLVM IR,
22 /// we instead operate on equivalence classes of instructions.
23 ///
24 /// TODO: This should be split into two enums: a runtime entry point enum
25 /// (possibly united with the ARCRuntimeEntrypoint class) and an enum that deals
26 /// with effects of instructions in the ARC model (which would handle the notion
27 /// of a User or CallOrUser).
28 enum class ARCInstKind {
29 Retain, ///< objc_retain
30 RetainRV, ///< objc_retainAutoreleasedReturnValue
31 UnsafeClaimRV, ///< objc_unsafeClaimAutoreleasedReturnValue
32 RetainBlock, ///< objc_retainBlock
33 Release, ///< objc_release
34 Autorelease, ///< objc_autorelease
35 AutoreleaseRV, ///< objc_autoreleaseReturnValue
36 AutoreleasepoolPush, ///< objc_autoreleasePoolPush
37 AutoreleasepoolPop, ///< objc_autoreleasePoolPop
38 NoopCast, ///< objc_retainedObject, etc.
39 FusedRetainAutorelease, ///< objc_retainAutorelease
40 FusedRetainAutoreleaseRV, ///< objc_retainAutoreleaseReturnValue
41 LoadWeakRetained, ///< objc_loadWeakRetained (primitive)
42 StoreWeak, ///< objc_storeWeak (primitive)
43 InitWeak, ///< objc_initWeak (derived)
44 LoadWeak, ///< objc_loadWeak (derived)
45 MoveWeak, ///< objc_moveWeak (derived)
46 CopyWeak, ///< objc_copyWeak (derived)
47 DestroyWeak, ///< objc_destroyWeak (derived)
48 StoreStrong, ///< objc_storeStrong (derived)
49 IntrinsicUser, ///< llvm.objc.clang.arc.use
50 CallOrUser, ///< could call objc_release and/or "use" pointers
51 Call, ///< could call objc_release
52 User, ///< could "use" a pointer
53 None ///< anything that is inert from an ARC perspective.
54 };
55
56 raw_ostream &operator<<(raw_ostream &OS, const ARCInstKind Class);
57
58 /// Test if the given class is a kind of user.
59 bool IsUser(ARCInstKind Class);
60
61 /// Test if the given class is objc_retain or equivalent.
62 bool IsRetain(ARCInstKind Class);
63
64 /// Test if the given class is objc_autorelease or equivalent.
65 bool IsAutorelease(ARCInstKind Class);
66
67 /// Test if the given class represents instructions which return their
68 /// argument verbatim.
69 bool IsForwarding(ARCInstKind Class);
70
71 /// Test if the given class represents instructions which do nothing if
72 /// passed a null pointer.
73 bool IsNoopOnNull(ARCInstKind Class);
74
75 /// Test if the given class represents instructions which do nothing if
76 /// passed a global variable.
77 bool IsNoopOnGlobal(ARCInstKind Class);
78
79 /// Test if the given class represents instructions which are always safe
80 /// to mark with the "tail" keyword.
81 bool IsAlwaysTail(ARCInstKind Class);
82
83 /// Test if the given class represents instructions which are never safe
84 /// to mark with the "tail" keyword.
85 bool IsNeverTail(ARCInstKind Class);
86
87 /// Test if the given class represents instructions which are always safe
88 /// to mark with the nounwind attribute.
89 bool IsNoThrow(ARCInstKind Class);
90
91 /// Test whether the given instruction can autorelease any pointer or cause an
92 /// autoreleasepool pop.
93 bool CanInterruptRV(ARCInstKind Class);
94
95 /// Determine if F is one of the special known Functions. If it isn't,
96 /// return ARCInstKind::CallOrUser.
97 ARCInstKind GetFunctionClass(const Function *F);
98
99 /// Determine which objc runtime call instruction class V belongs to.
100 ///
101 /// This is similar to GetARCInstKind except that it only detects objc
102 /// runtime calls. This allows it to be faster.
103 ///
GetBasicARCInstKind(const Value * V)104 inline ARCInstKind GetBasicARCInstKind(const Value *V) {
105 if (const CallInst *CI = dyn_cast<CallInst>(V)) {
106 if (const Function *F = CI->getCalledFunction())
107 return GetFunctionClass(F);
108 // Otherwise, be conservative.
109 return ARCInstKind::CallOrUser;
110 }
111
112 // Otherwise, be conservative.
113 return isa<InvokeInst>(V) ? ARCInstKind::CallOrUser : ARCInstKind::User;
114 }
115
116 /// Map V to its ARCInstKind equivalence class.
117 ARCInstKind GetARCInstKind(const Value *V);
118
119 /// Returns false if conservatively we can prove that any instruction mapped to
120 /// this kind can not decrement ref counts. Returns true otherwise.
121 bool CanDecrementRefCount(ARCInstKind Kind);
122
123 } // end namespace objcarc
124 } // end namespace llvm
125
126 #endif
127