ObjCRetainCount.h revision 263508
1//==-- ObjCRetainCount.h - Retain count summaries for Cocoa -------*- 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// This file defines the core data structures for retain count "summaries" 11// for Objective-C and Core Foundation APIs. These summaries are used 12// by the static analyzer to summarize the retain/release effects of 13// function and method calls. This drives a path-sensitive typestate 14// analysis in the static analyzer, but can also potentially be used by 15// other clients. 16// 17//===----------------------------------------------------------------------===// 18 19#ifndef LLVM_CLANG_OBJCRETAINCOUNT_H 20#define LLVM_CLANG_OBJCRETAINCOUNT_H 21 22namespace clang { namespace ento { namespace objc_retain { 23 24/// An ArgEffect summarizes the retain count behavior on an argument or receiver 25/// to a function or method. 26enum ArgEffect { 27 /// There is no effect. 28 DoNothing, 29 30 /// The argument is treated as if an -autorelease message had been sent to 31 /// the referenced object. 32 Autorelease, 33 34 /// The argument is treated as if an -dealloc message had been sent to 35 /// the referenced object. 36 Dealloc, 37 38 /// The argument has its reference count decreased by 1. This is as 39 /// if CFRelease has been called on the argument. 40 DecRef, 41 42 /// The argument has its reference count decreased by 1. This is as 43 /// if a -release message has been sent to the argument. This differs 44 /// in behavior from DecRef when GC is enabled. 45 DecRefMsg, 46 47 /// The argument has its reference count decreased by 1 to model 48 /// a transferred bridge cast under ARC. 49 DecRefBridgedTransferred, 50 51 /// The argument has its reference count increased by 1. This is as 52 /// if a -retain message has been sent to the argument. This differs 53 /// in behavior from IncRef when GC is enabled. 54 IncRefMsg, 55 56 /// The argument has its reference count increased by 1. This is as 57 /// if CFRetain has been called on the argument. 58 IncRef, 59 60 /// The argument acts as if has been passed to CFMakeCollectable, which 61 /// transfers the object to the Garbage Collector under GC. 62 MakeCollectable, 63 64 /// The argument is treated as potentially escaping, meaning that 65 /// even when its reference count hits 0 it should be treated as still 66 /// possibly being alive as someone else *may* be holding onto the object. 67 MayEscape, 68 69 /// All typestate tracking of the object ceases. This is usually employed 70 /// when the effect of the call is completely unknown. 71 StopTracking, 72 73 /// All typestate tracking of the object ceases. Unlike StopTracking, 74 /// this is also enforced when the method body is inlined. 75 /// 76 /// In some cases, we obtain a better summary for this checker 77 /// by looking at the call site than by inlining the function. 78 /// Signifies that we should stop tracking the symbol even if 79 /// the function is inlined. 80 StopTrackingHard, 81 82 /// Performs the combined functionality of DecRef and StopTrackingHard. 83 /// 84 /// The models the effect that the called function decrements the reference 85 /// count of the argument and all typestate tracking on that argument 86 /// should cease. 87 DecRefAndStopTrackingHard, 88 89 /// Performs the combined functionality of DecRefMsg and StopTrackingHard. 90 /// 91 /// The models the effect that the called function decrements the reference 92 /// count of the argument and all typestate tracking on that argument 93 /// should cease. 94 DecRefMsgAndStopTrackingHard 95}; 96 97/// RetEffect summarizes a call's retain/release behavior with respect 98/// to its return value. 99class RetEffect { 100public: 101 enum Kind { 102 /// Indicates that no retain count information is tracked for 103 /// the return value. 104 NoRet, 105 /// Indicates that the returned value is an owned (+1) symbol. 106 OwnedSymbol, 107 /// Indicates that the returned value is an owned (+1) symbol and 108 /// that it should be treated as freshly allocated. 109 OwnedAllocatedSymbol, 110 /// Indicates that the returned value is an object with retain count 111 /// semantics but that it is not owned (+0). This is the default 112 /// for getters, etc. 113 NotOwnedSymbol, 114 /// Indicates that the object is not owned and controlled by the 115 /// Garbage collector. 116 GCNotOwnedSymbol, 117 /// Indicates that the object is not owned and controlled by ARC. 118 ARCNotOwnedSymbol, 119 /// Indicates that the return value is an owned object when the 120 /// receiver is also a tracked object. 121 OwnedWhenTrackedReceiver, 122 // Treat this function as returning a non-tracked symbol even if 123 // the function has been inlined. This is used where the call 124 // site summary is more presise than the summary indirectly produced 125 // by inlining the function 126 NoRetHard 127 }; 128 129 /// Determines the object kind of a tracked object. 130 enum ObjKind { 131 /// Indicates that the tracked object is a CF object. This is 132 /// important between GC and non-GC code. 133 CF, 134 /// Indicates that the tracked object is an Objective-C object. 135 ObjC, 136 /// Indicates that the tracked object could be a CF or Objective-C object. 137 AnyObj 138 }; 139 140private: 141 Kind K; 142 ObjKind O; 143 144 RetEffect(Kind k, ObjKind o = AnyObj) : K(k), O(o) {} 145 146public: 147 Kind getKind() const { return K; } 148 149 ObjKind getObjKind() const { return O; } 150 151 bool isOwned() const { 152 return K == OwnedSymbol || K == OwnedAllocatedSymbol || 153 K == OwnedWhenTrackedReceiver; 154 } 155 156 bool notOwned() const { 157 return K == NotOwnedSymbol || K == ARCNotOwnedSymbol; 158 } 159 160 bool operator==(const RetEffect &Other) const { 161 return K == Other.K && O == Other.O; 162 } 163 164 static RetEffect MakeOwnedWhenTrackedReceiver() { 165 return RetEffect(OwnedWhenTrackedReceiver, ObjC); 166 } 167 168 static RetEffect MakeOwned(ObjKind o, bool isAllocated = false) { 169 return RetEffect(isAllocated ? OwnedAllocatedSymbol : OwnedSymbol, o); 170 } 171 static RetEffect MakeNotOwned(ObjKind o) { 172 return RetEffect(NotOwnedSymbol, o); 173 } 174 static RetEffect MakeGCNotOwned() { 175 return RetEffect(GCNotOwnedSymbol, ObjC); 176 } 177 static RetEffect MakeARCNotOwned() { 178 return RetEffect(ARCNotOwnedSymbol, ObjC); 179 } 180 static RetEffect MakeNoRet() { 181 return RetEffect(NoRet); 182 } 183 static RetEffect MakeNoRetHard() { 184 return RetEffect(NoRetHard); 185 } 186}; 187 188/// Encapsulates the retain count semantics on the arguments, return value, 189/// and receiver (if any) of a function/method call. 190/// 191/// Note that construction of these objects is not highly efficient. That 192/// is okay for clients where creating these objects isn't really a bottleneck. 193/// The purpose of the API is to provide something simple. The actual 194/// static analyzer checker that implements retain/release typestate 195/// tracking uses something more efficient. 196class CallEffects { 197 llvm::SmallVector<ArgEffect, 10> Args; 198 RetEffect Ret; 199 ArgEffect Receiver; 200 201 CallEffects(const RetEffect &R) : Ret(R) {} 202 203public: 204 /// Returns the argument effects for a call. 205 llvm::ArrayRef<ArgEffect> getArgs() const { return Args; } 206 207 /// Returns the effects on the receiver. 208 ArgEffect getReceiver() const { return Receiver; } 209 210 /// Returns the effect on the return value. 211 RetEffect getReturnValue() const { return Ret; } 212 213 /// Return the CallEfect for a given Objective-C method. 214 static CallEffects getEffect(const ObjCMethodDecl *MD); 215 216 /// Return the CallEfect for a given C/C++ function. 217 static CallEffects getEffect(const FunctionDecl *FD); 218}; 219 220}}} 221 222#endif 223 224