1 //==-- ObjCRetainCount.h - Retain count summaries for Cocoa -------*- C++ -*--//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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
17 //===----------------------------------------------------------------------===//
19 #ifndef LLVM_CLANG_OBJCRETAINCOUNT_H
20 #define LLVM_CLANG_OBJCRETAINCOUNT_H
22 namespace clang { namespace ento { namespace objc_retain {
24 /// An ArgEffect summarizes the retain count behavior on an argument or receiver
25 /// to a function or method.
27 /// There is no effect.
30 /// The argument is treated as if an -autorelease message had been sent to
31 /// the referenced object.
34 /// The argument is treated as if an -dealloc message had been sent to
35 /// the referenced object.
38 /// The argument has its reference count decreased by 1. This is as
39 /// if CFRelease has been called on the argument.
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.
47 /// The argument has its reference count decreased by 1 to model
48 /// a transferred bridge cast under ARC.
49 DecRefBridgedTransferred,
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.
56 /// The argument has its reference count increased by 1. This is as
57 /// if CFRetain has been called on the argument.
60 /// The argument acts as if has been passed to CFMakeCollectable, which
61 /// transfers the object to the Garbage Collector under GC.
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.
69 /// All typestate tracking of the object ceases. This is usually employed
70 /// when the effect of the call is completely unknown.
73 /// All typestate tracking of the object ceases. Unlike StopTracking,
74 /// this is also enforced when the method body is inlined.
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.
82 /// Performs the combined functionality of DecRef and StopTrackingHard.
84 /// The models the effect that the called function decrements the reference
85 /// count of the argument and all typestate tracking on that argument
87 DecRefAndStopTrackingHard,
89 /// Performs the combined functionality of DecRefMsg and StopTrackingHard.
91 /// The models the effect that the called function decrements the reference
92 /// count of the argument and all typestate tracking on that argument
94 DecRefMsgAndStopTrackingHard
97 /// RetEffect summarizes a call's retain/release behavior with respect
98 /// to its return value.
102 /// Indicates that no retain count information is tracked for
103 /// the return value.
105 /// Indicates that the returned value is an owned (+1) symbol.
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.
114 /// Indicates that the object is not owned and controlled by the
115 /// Garbage collector.
117 /// Indicates that the object is not owned and controlled by ARC.
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
129 /// Determines the object kind of a tracked object.
131 /// Indicates that the tracked object is a CF object. This is
132 /// important between GC and non-GC code.
134 /// Indicates that the tracked object is an Objective-C object.
136 /// Indicates that the tracked object could be a CF or Objective-C object.
144 RetEffect(Kind k, ObjKind o = AnyObj) : K(k), O(o) {}
147 Kind getKind() const { return K; }
149 ObjKind getObjKind() const { return O; }
151 bool isOwned() const {
152 return K == OwnedSymbol || K == OwnedAllocatedSymbol ||
153 K == OwnedWhenTrackedReceiver;
156 bool notOwned() const {
157 return K == NotOwnedSymbol || K == ARCNotOwnedSymbol;
160 bool operator==(const RetEffect &Other) const {
161 return K == Other.K && O == Other.O;
164 static RetEffect MakeOwnedWhenTrackedReceiver() {
165 return RetEffect(OwnedWhenTrackedReceiver, ObjC);
168 static RetEffect MakeOwned(ObjKind o, bool isAllocated = false) {
169 return RetEffect(isAllocated ? OwnedAllocatedSymbol : OwnedSymbol, o);
171 static RetEffect MakeNotOwned(ObjKind o) {
172 return RetEffect(NotOwnedSymbol, o);
174 static RetEffect MakeGCNotOwned() {
175 return RetEffect(GCNotOwnedSymbol, ObjC);
177 static RetEffect MakeARCNotOwned() {
178 return RetEffect(ARCNotOwnedSymbol, ObjC);
180 static RetEffect MakeNoRet() {
181 return RetEffect(NoRet);
183 static RetEffect MakeNoRetHard() {
184 return RetEffect(NoRetHard);
188 /// Encapsulates the retain count semantics on the arguments, return value,
189 /// and receiver (if any) of a function/method call.
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.
197 llvm::SmallVector<ArgEffect, 10> Args;
201 CallEffects(const RetEffect &R) : Ret(R) {}
204 /// Returns the argument effects for a call.
205 llvm::ArrayRef<ArgEffect> getArgs() const { return Args; }
207 /// Returns the effects on the receiver.
208 ArgEffect getReceiver() const { return Receiver; }
210 /// Returns the effect on the return value.
211 RetEffect getReturnValue() const { return Ret; }
213 /// Return the CallEfect for a given Objective-C method.
214 static CallEffects getEffect(const ObjCMethodDecl *MD);
216 /// Return the CallEfect for a given C/C++ function.
217 static CallEffects getEffect(const FunctionDecl *FD);