1 //===- ObjCARCInstKind.h - ARC instruction equivalence classes --*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #ifndef LLVM_ANALYSIS_OBJCARCINSTKIND_H
11 #define LLVM_ANALYSIS_OBJCARCINSTKIND_H
12
13 #include "llvm/IR/Function.h"
14 #include "llvm/IR/Intrinsics.h"
15 #include "llvm/IR/Instructions.h"
16
17 namespace llvm {
18 namespace objcarc {
19
20 /// \enum ARCInstKind
21 ///
22 /// Equivalence classes of instructions in the ARC Model.
23 ///
24 /// Since we do not have "instructions" to represent ARC concepts in LLVM IR,
25 /// we instead operate on equivalence classes of instructions.
26 ///
27 /// TODO: This should be split into two enums: a runtime entry point enum
28 /// (possibly united with the ARCRuntimeEntrypoint class) and an enum that deals
29 /// with effects of instructions in the ARC model (which would handle the notion
30 /// of a User or CallOrUser).
31 enum class ARCInstKind {
32 Retain, ///< objc_retain
33 RetainRV, ///< objc_retainAutoreleasedReturnValue
34 ClaimRV, ///< objc_unsafeClaimAutoreleasedReturnValue
35 RetainBlock, ///< objc_retainBlock
36 Release, ///< objc_release
37 Autorelease, ///< objc_autorelease
38 AutoreleaseRV, ///< objc_autoreleaseReturnValue
39 AutoreleasepoolPush, ///< objc_autoreleasePoolPush
40 AutoreleasepoolPop, ///< objc_autoreleasePoolPop
41 NoopCast, ///< objc_retainedObject, etc.
42 FusedRetainAutorelease, ///< objc_retainAutorelease
43 FusedRetainAutoreleaseRV, ///< objc_retainAutoreleaseReturnValue
44 LoadWeakRetained, ///< objc_loadWeakRetained (primitive)
45 StoreWeak, ///< objc_storeWeak (primitive)
46 InitWeak, ///< objc_initWeak (derived)
47 LoadWeak, ///< objc_loadWeak (derived)
48 MoveWeak, ///< objc_moveWeak (derived)
49 CopyWeak, ///< objc_copyWeak (derived)
50 DestroyWeak, ///< objc_destroyWeak (derived)
51 StoreStrong, ///< objc_storeStrong (derived)
52 IntrinsicUser, ///< llvm.objc.clang.arc.use
53 CallOrUser, ///< could call objc_release and/or "use" pointers
54 Call, ///< could call objc_release
55 User, ///< could "use" a pointer
56 None ///< anything that is inert from an ARC perspective.
57 };
58
59 raw_ostream &operator<<(raw_ostream &OS, const ARCInstKind Class);
60
61 /// Test if the given class is a kind of user.
62 bool IsUser(ARCInstKind Class);
63
64 /// Test if the given class is objc_retain or equivalent.
65 bool IsRetain(ARCInstKind Class);
66
67 /// Test if the given class is objc_autorelease or equivalent.
68 bool IsAutorelease(ARCInstKind Class);
69
70 /// Test if the given class represents instructions which return their
71 /// argument verbatim.
72 bool IsForwarding(ARCInstKind Class);
73
74 /// Test if the given class represents instructions which do nothing if
75 /// passed a null pointer.
76 bool IsNoopOnNull(ARCInstKind Class);
77
78 /// Test if the given class represents instructions which are always safe
79 /// to mark with the "tail" keyword.
80 bool IsAlwaysTail(ARCInstKind Class);
81
82 /// Test if the given class represents instructions which are never safe
83 /// to mark with the "tail" keyword.
84 bool IsNeverTail(ARCInstKind Class);
85
86 /// Test if the given class represents instructions which are always safe
87 /// to mark with the nounwind attribute.
88 bool IsNoThrow(ARCInstKind Class);
89
90 /// Test whether the given instruction can autorelease any pointer or cause an
91 /// autoreleasepool pop.
92 bool CanInterruptRV(ARCInstKind Class);
93
94 /// Determine if F is one of the special known Functions. If it isn't,
95 /// return ARCInstKind::CallOrUser.
96 ARCInstKind GetFunctionClass(const Function *F);
97
98 /// Determine which objc runtime call instruction class V belongs to.
99 ///
100 /// This is similar to GetARCInstKind except that it only detects objc
101 /// runtime calls. This allows it to be faster.
102 ///
GetBasicARCInstKind(const Value * V)103 inline ARCInstKind GetBasicARCInstKind(const Value *V) {
104 if (const CallInst *CI = dyn_cast<CallInst>(V)) {
105 if (const Function *F = CI->getCalledFunction())
106 return GetFunctionClass(F);
107 // Otherwise, be conservative.
108 return ARCInstKind::CallOrUser;
109 }
110
111 // Otherwise, be conservative.
112 return isa<InvokeInst>(V) ? ARCInstKind::CallOrUser : ARCInstKind::User;
113 }
114
115 /// Map V to its ARCInstKind equivalence class.
116 ARCInstKind GetARCInstKind(const Value *V);
117
118 /// Returns false if conservatively we can prove that any instruction mapped to
119 /// this kind can not decrement ref counts. Returns true otherwise.
120 bool CanDecrementRefCount(ARCInstKind Kind);
121
122 } // end namespace objcarc
123 } // end namespace llvm
124
125 #endif
126