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//==-- RetainCountChecker.cpp - Checks for leaks and other issues -*- C++ -*--//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the methods for RetainCountChecker, which implements
// a reference count checker for Core Foundation and Cocoa on (Mac OS X).
//
//===----------------------------------------------------------------------===//
#include "AllocationDiagnostics.h"
#include "ClangSACheckers.h"
#include "SelectorExtras.h"
#include "clang/AST/Attr.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/ParentMap.h"
#include "clang/Analysis/DomainSpecific/CocoaConventions.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/SourceManager.h"
#include "clang/StaticAnalyzer/Checkers/ObjCRetainCount.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/ImmutableList.h"
#include "llvm/ADT/ImmutableMap.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include <cstdarg>
#include <utility>
using namespace clang;
using namespace ento;
using namespace objc_retain;
using llvm::StrInStrNoCase;
//===----------------------------------------------------------------------===//
// Adapters for FoldingSet.
//===----------------------------------------------------------------------===//
namespace llvm {
template <> struct FoldingSetTrait<ArgEffect> {
static inline void Profile(const ArgEffect X, FoldingSetNodeID &ID) {
ID.AddInteger((unsigned) X);
}
};
template <> struct FoldingSetTrait<RetEffect> {
static inline void Profile(const RetEffect &X, FoldingSetNodeID &ID) {
ID.AddInteger((unsigned) X.getKind());
ID.AddInteger((unsigned) X.getObjKind());
}
};
} // end llvm namespace
//===----------------------------------------------------------------------===//
// Reference-counting logic (typestate + counts).
//===----------------------------------------------------------------------===//
/// ArgEffects summarizes the effects of a function/method call on all of
/// its arguments.
typedef llvm::ImmutableMap<unsigned,ArgEffect> ArgEffects;
namespace {
class RefVal {
public:
enum Kind {
Owned = 0, // Owning reference.
NotOwned, // Reference is not owned by still valid (not freed).
Released, // Object has been released.
ReturnedOwned, // Returned object passes ownership to caller.
ReturnedNotOwned, // Return object does not pass ownership to caller.
ERROR_START,
ErrorDeallocNotOwned, // -dealloc called on non-owned object.
ErrorDeallocGC, // Calling -dealloc with GC enabled.
ErrorUseAfterRelease, // Object used after released.
ErrorReleaseNotOwned, // Release of an object that was not owned.
ERROR_LEAK_START,
ErrorLeak, // A memory leak due to excessive reference counts.
ErrorLeakReturned, // A memory leak due to the returning method not having
// the correct naming conventions.
ErrorGCLeakReturned,
ErrorOverAutorelease,
ErrorReturnedNotOwned
};
/// Tracks how an object referenced by an ivar has been used.
///
/// This accounts for us not knowing if an arbitrary ivar is supposed to be
/// stored at +0 or +1.
enum class IvarAccessHistory {
None,
AccessedDirectly,
ReleasedAfterDirectAccess
};
private:
/// The number of outstanding retains.
unsigned Cnt;
/// The number of outstanding autoreleases.
unsigned ACnt;
/// The (static) type of the object at the time we started tracking it.
QualType T;
/// The current state of the object.
///
/// See the RefVal::Kind enum for possible values.
unsigned RawKind : 5;
/// The kind of object being tracked (CF or ObjC), if known.
///
/// See the RetEffect::ObjKind enum for possible values.
unsigned RawObjectKind : 2;
/// True if the current state and/or retain count may turn out to not be the
/// best possible approximation of the reference counting state.
///
/// If true, the checker may decide to throw away ("override") this state
/// in favor of something else when it sees the object being used in new ways.
///
/// This setting should not be propagated to state derived from this state.
/// Once we start deriving new states, it would be inconsistent to override
/// them.
unsigned RawIvarAccessHistory : 2;
RefVal(Kind k, RetEffect::ObjKind o, unsigned cnt, unsigned acnt, QualType t,
IvarAccessHistory IvarAccess)
: Cnt(cnt), ACnt(acnt), T(t), RawKind(static_cast<unsigned>(k)),
RawObjectKind(static_cast<unsigned>(o)),
RawIvarAccessHistory(static_cast<unsigned>(IvarAccess)) {
assert(getKind() == k && "not enough bits for the kind");
assert(getObjKind() == o && "not enough bits for the object kind");
assert(getIvarAccessHistory() == IvarAccess && "not enough bits");
}
public:
Kind getKind() const { return static_cast<Kind>(RawKind); }
RetEffect::ObjKind getObjKind() const {
return static_cast<RetEffect::ObjKind>(RawObjectKind);
}
unsigned getCount() const { return Cnt; }
unsigned getAutoreleaseCount() const { return ACnt; }
unsigned getCombinedCounts() const { return Cnt + ACnt; }
void clearCounts() {
Cnt = 0;
ACnt = 0;
}
void setCount(unsigned i) {
Cnt = i;
}
void setAutoreleaseCount(unsigned i) {
ACnt = i;
}
QualType getType() const { return T; }
/// Returns what the analyzer knows about direct accesses to a particular
/// instance variable.
///
/// If the object with this refcount wasn't originally from an Objective-C
/// ivar region, this should always return IvarAccessHistory::None.
IvarAccessHistory getIvarAccessHistory() const {
return static_cast<IvarAccessHistory>(RawIvarAccessHistory);
}
bool isOwned() const {
return getKind() == Owned;
}
bool isNotOwned() const {
return getKind() == NotOwned;
}
bool isReturnedOwned() const {
return getKind() == ReturnedOwned;
}
bool isReturnedNotOwned() const {
return getKind() == ReturnedNotOwned;
}
/// Create a state for an object whose lifetime is the responsibility of the
/// current function, at least partially.
///
/// Most commonly, this is an owned object with a retain count of +1.
static RefVal makeOwned(RetEffect::ObjKind o, QualType t,
unsigned Count = 1) {
return RefVal(Owned, o, Count, 0, t, IvarAccessHistory::None);
}
/// Create a state for an object whose lifetime is not the responsibility of
/// the current function.
///
/// Most commonly, this is an unowned object with a retain count of +0.
static RefVal makeNotOwned(RetEffect::ObjKind o, QualType t,
unsigned Count = 0) {
return RefVal(NotOwned, o, Count, 0, t, IvarAccessHistory::None);
}
RefVal operator-(size_t i) const {
return RefVal(getKind(), getObjKind(), getCount() - i,
getAutoreleaseCount(), getType(), getIvarAccessHistory());
}
RefVal operator+(size_t i) const {
return RefVal(getKind(), getObjKind(), getCount() + i,
getAutoreleaseCount(), getType(), getIvarAccessHistory());
}
RefVal operator^(Kind k) const {
return RefVal(k, getObjKind(), getCount(), getAutoreleaseCount(),
getType(), getIvarAccessHistory());
}
RefVal autorelease() const {
return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount()+1,
getType(), getIvarAccessHistory());
}
RefVal withIvarAccess() const {
assert(getIvarAccessHistory() == IvarAccessHistory::None);
return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount(),
getType(), IvarAccessHistory::AccessedDirectly);
}
RefVal releaseViaIvar() const {
assert(getIvarAccessHistory() == IvarAccessHistory::AccessedDirectly);
return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount(),
getType(), IvarAccessHistory::ReleasedAfterDirectAccess);
}
// Comparison, profiling, and pretty-printing.
bool hasSameState(const RefVal &X) const {
return getKind() == X.getKind() && Cnt == X.Cnt && ACnt == X.ACnt &&
getIvarAccessHistory() == X.getIvarAccessHistory();
}
bool operator==(const RefVal& X) const {
return T == X.T && hasSameState(X) && getObjKind() == X.getObjKind();
}
void Profile(llvm::FoldingSetNodeID& ID) const {
ID.Add(T);
ID.AddInteger(RawKind);
ID.AddInteger(Cnt);
ID.AddInteger(ACnt);
ID.AddInteger(RawObjectKind);
ID.AddInteger(RawIvarAccessHistory);
}
void print(raw_ostream &Out) const;
};
void RefVal::print(raw_ostream &Out) const {
if (!T.isNull())
Out << "Tracked " << T.getAsString() << '/';
switch (getKind()) {
default: llvm_unreachable("Invalid RefVal kind");
case Owned: {
Out << "Owned";
unsigned cnt = getCount();
if (cnt) Out << " (+ " << cnt << ")";
break;
}
case NotOwned: {
Out << "NotOwned";
unsigned cnt = getCount();
if (cnt) Out << " (+ " << cnt << ")";
break;
}
case ReturnedOwned: {
Out << "ReturnedOwned";
unsigned cnt = getCount();
if (cnt) Out << " (+ " << cnt << ")";
break;
}
case ReturnedNotOwned: {
Out << "ReturnedNotOwned";
unsigned cnt = getCount();
if (cnt) Out << " (+ " << cnt << ")";
break;
}
case Released:
Out << "Released";
break;
case ErrorDeallocGC:
Out << "-dealloc (GC)";
break;
case ErrorDeallocNotOwned:
Out << "-dealloc (not-owned)";
break;
case ErrorLeak:
Out << "Leaked";
break;
case ErrorLeakReturned:
Out << "Leaked (Bad naming)";
break;
case ErrorGCLeakReturned:
Out << "Leaked (GC-ed at return)";
break;
case ErrorUseAfterRelease:
Out << "Use-After-Release [ERROR]";
break;
case ErrorReleaseNotOwned:
Out << "Release of Not-Owned [ERROR]";
break;
case RefVal::ErrorOverAutorelease:
Out << "Over-autoreleased";
break;
case RefVal::ErrorReturnedNotOwned:
Out << "Non-owned object returned instead of owned";
break;
}
switch (getIvarAccessHistory()) {
case IvarAccessHistory::None:
break;
case IvarAccessHistory::AccessedDirectly:
Out << " [direct ivar access]";
break;
case IvarAccessHistory::ReleasedAfterDirectAccess:
Out << " [released after direct ivar access]";
}
if (ACnt) {
Out << " [autorelease -" << ACnt << ']';
}
}
} //end anonymous namespace
//===----------------------------------------------------------------------===//
// RefBindings - State used to track object reference counts.
//===----------------------------------------------------------------------===//
REGISTER_MAP_WITH_PROGRAMSTATE(RefBindings, SymbolRef, RefVal)
static inline const RefVal *getRefBinding(ProgramStateRef State,
SymbolRef Sym) {
return State->get<RefBindings>(Sym);
}
static inline ProgramStateRef setRefBinding(ProgramStateRef State,
SymbolRef Sym, RefVal Val) {
return State->set<RefBindings>(Sym, Val);
}
static ProgramStateRef removeRefBinding(ProgramStateRef State, SymbolRef Sym) {
return State->remove<RefBindings>(Sym);
}
//===----------------------------------------------------------------------===//
// Function/Method behavior summaries.
//===----------------------------------------------------------------------===//
namespace {
class RetainSummary {
/// Args - a map of (index, ArgEffect) pairs, where index
/// specifies the argument (starting from 0). This can be sparsely
/// populated; arguments with no entry in Args use 'DefaultArgEffect'.
ArgEffects Args;
/// DefaultArgEffect - The default ArgEffect to apply to arguments that
/// do not have an entry in Args.
ArgEffect DefaultArgEffect;
/// Receiver - If this summary applies to an Objective-C message expression,
/// this is the effect applied to the state of the receiver.
ArgEffect Receiver;
/// Ret - The effect on the return value. Used to indicate if the
/// function/method call returns a new tracked symbol.
RetEffect Ret;
public:
RetainSummary(ArgEffects A, RetEffect R, ArgEffect defaultEff,
ArgEffect ReceiverEff)
: Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R) {}
/// getArg - Return the argument effect on the argument specified by
/// idx (starting from 0).
ArgEffect getArg(unsigned idx) const {
if (const ArgEffect *AE = Args.lookup(idx))
return *AE;
return DefaultArgEffect;
}
void addArg(ArgEffects::Factory &af, unsigned idx, ArgEffect e) {
Args = af.add(Args, idx, e);
}
/// setDefaultArgEffect - Set the default argument effect.
void setDefaultArgEffect(ArgEffect E) {
DefaultArgEffect = E;
}
/// getRetEffect - Returns the effect on the return value of the call.
RetEffect getRetEffect() const { return Ret; }
/// setRetEffect - Set the effect of the return value of the call.
void setRetEffect(RetEffect E) { Ret = E; }
/// Sets the effect on the receiver of the message.
void setReceiverEffect(ArgEffect e) { Receiver = e; }
/// getReceiverEffect - Returns the effect on the receiver of the call.
/// This is only meaningful if the summary applies to an ObjCMessageExpr*.
ArgEffect getReceiverEffect() const { return Receiver; }
/// Test if two retain summaries are identical. Note that merely equivalent
/// summaries are not necessarily identical (for example, if an explicit
/// argument effect matches the default effect).
bool operator==(const RetainSummary &Other) const {
return Args == Other.Args && DefaultArgEffect == Other.DefaultArgEffect &&
Receiver == Other.Receiver && Ret == Other.Ret;
}
/// Profile this summary for inclusion in a FoldingSet.
void Profile(llvm::FoldingSetNodeID& ID) const {
ID.Add(Args);
ID.Add(DefaultArgEffect);
ID.Add(Receiver);
ID.Add(Ret);
}
/// A retain summary is simple if it has no ArgEffects other than the default.
bool isSimple() const {
return Args.isEmpty();
}
private:
ArgEffects getArgEffects() const { return Args; }
ArgEffect getDefaultArgEffect() const { return DefaultArgEffect; }
friend class RetainSummaryManager;
};
} // end anonymous namespace
//===----------------------------------------------------------------------===//
// Data structures for constructing summaries.
//===----------------------------------------------------------------------===//
namespace {
class ObjCSummaryKey {
IdentifierInfo* II;
Selector S;
public:
ObjCSummaryKey(IdentifierInfo* ii, Selector s)
: II(ii), S(s) {}
ObjCSummaryKey(const ObjCInterfaceDecl *d, Selector s)
: II(d ? d->getIdentifier() : nullptr), S(s) {}
ObjCSummaryKey(Selector s)
: II(nullptr), S(s) {}
IdentifierInfo *getIdentifier() const { return II; }
Selector getSelector() const { return S; }
};
} // end anonymous namespace
namespace llvm {
template <> struct DenseMapInfo<ObjCSummaryKey> {
static inline ObjCSummaryKey getEmptyKey() {
return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getEmptyKey(),
DenseMapInfo<Selector>::getEmptyKey());
}
static inline ObjCSummaryKey getTombstoneKey() {
return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getTombstoneKey(),
DenseMapInfo<Selector>::getTombstoneKey());
}
static unsigned getHashValue(const ObjCSummaryKey &V) {
typedef std::pair<IdentifierInfo*, Selector> PairTy;
return DenseMapInfo<PairTy>::getHashValue(PairTy(V.getIdentifier(),
V.getSelector()));
}
static bool isEqual(const ObjCSummaryKey& LHS, const ObjCSummaryKey& RHS) {
return LHS.getIdentifier() == RHS.getIdentifier() &&
LHS.getSelector() == RHS.getSelector();
}
};
} // end llvm namespace
namespace {
class ObjCSummaryCache {
typedef llvm::DenseMap<ObjCSummaryKey, const RetainSummary *> MapTy;
MapTy M;
public:
ObjCSummaryCache() {}
const RetainSummary * find(const ObjCInterfaceDecl *D, Selector S) {
// Do a lookup with the (D,S) pair. If we find a match return
// the iterator.
ObjCSummaryKey K(D, S);
MapTy::iterator I = M.find(K);
if (I != M.end())
return I->second;
if (!D)
return nullptr;
// Walk the super chain. If we find a hit with a parent, we'll end
// up returning that summary. We actually allow that key (null,S), as
// we cache summaries for the null ObjCInterfaceDecl* to allow us to
// generate initial summaries without having to worry about NSObject
// being declared.
// FIXME: We may change this at some point.
for (ObjCInterfaceDecl *C=D->getSuperClass() ;; C=C->getSuperClass()) {
if ((I = M.find(ObjCSummaryKey(C, S))) != M.end())
break;
if (!C)
return nullptr;
}
// Cache the summary with original key to make the next lookup faster
// and return the iterator.
const RetainSummary *Summ = I->second;
M[K] = Summ;
return Summ;
}
const RetainSummary *find(IdentifierInfo* II, Selector S) {
// FIXME: Class method lookup. Right now we dont' have a good way
// of going between IdentifierInfo* and the class hierarchy.
MapTy::iterator I = M.find(ObjCSummaryKey(II, S));
if (I == M.end())
I = M.find(ObjCSummaryKey(S));
return I == M.end() ? nullptr : I->second;
}
const RetainSummary *& operator[](ObjCSummaryKey K) {
return M[K];
}
const RetainSummary *& operator[](Selector S) {
return M[ ObjCSummaryKey(S) ];
}
};
} // end anonymous namespace
//===----------------------------------------------------------------------===//
// Data structures for managing collections of summaries.
//===----------------------------------------------------------------------===//
namespace {
class RetainSummaryManager {
//==-----------------------------------------------------------------==//
// Typedefs.
//==-----------------------------------------------------------------==//
typedef llvm::DenseMap<const FunctionDecl*, const RetainSummary *>
FuncSummariesTy;
typedef ObjCSummaryCache ObjCMethodSummariesTy;
typedef llvm::FoldingSetNodeWrapper<RetainSummary> CachedSummaryNode;
//==-----------------------------------------------------------------==//
// Data.
//==-----------------------------------------------------------------==//
/// Ctx - The ASTContext object for the analyzed ASTs.
ASTContext &Ctx;
/// GCEnabled - Records whether or not the analyzed code runs in GC mode.
const bool GCEnabled;
/// Records whether or not the analyzed code runs in ARC mode.
const bool ARCEnabled;
/// FuncSummaries - A map from FunctionDecls to summaries.
FuncSummariesTy FuncSummaries;
/// ObjCClassMethodSummaries - A map from selectors (for instance methods)
/// to summaries.
ObjCMethodSummariesTy ObjCClassMethodSummaries;
/// ObjCMethodSummaries - A map from selectors to summaries.
ObjCMethodSummariesTy ObjCMethodSummaries;
/// BPAlloc - A BumpPtrAllocator used for allocating summaries, ArgEffects,
/// and all other data used by the checker.
llvm::BumpPtrAllocator BPAlloc;
/// AF - A factory for ArgEffects objects.
ArgEffects::Factory AF;
/// ScratchArgs - A holding buffer for construct ArgEffects.
ArgEffects ScratchArgs;
/// ObjCAllocRetE - Default return effect for methods returning Objective-C
/// objects.
RetEffect ObjCAllocRetE;
/// ObjCInitRetE - Default return effect for init methods returning
/// Objective-C objects.
RetEffect ObjCInitRetE;
/// SimpleSummaries - Used for uniquing summaries that don't have special
/// effects.
llvm::FoldingSet<CachedSummaryNode> SimpleSummaries;
//==-----------------------------------------------------------------==//
// Methods.
//==-----------------------------------------------------------------==//
/// getArgEffects - Returns a persistent ArgEffects object based on the
/// data in ScratchArgs.
ArgEffects getArgEffects();
enum UnaryFuncKind { cfretain, cfrelease, cfautorelease, cfmakecollectable };
const RetainSummary *getUnarySummary(const FunctionType* FT,
UnaryFuncKind func);
const RetainSummary *getCFSummaryCreateRule(const FunctionDecl *FD);
const RetainSummary *getCFSummaryGetRule(const FunctionDecl *FD);
const RetainSummary *getCFCreateGetRuleSummary(const FunctionDecl *FD);
const RetainSummary *getPersistentSummary(const RetainSummary &OldSumm);
const RetainSummary *getPersistentSummary(RetEffect RetEff,
ArgEffect ReceiverEff = DoNothing,
ArgEffect DefaultEff = MayEscape) {
RetainSummary Summ(getArgEffects(), RetEff, DefaultEff, ReceiverEff);
return getPersistentSummary(Summ);
}
const RetainSummary *getDoNothingSummary() {
return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
}
const RetainSummary *getDefaultSummary() {
return getPersistentSummary(RetEffect::MakeNoRet(),
DoNothing, MayEscape);
}
const RetainSummary *getPersistentStopSummary() {
return getPersistentSummary(RetEffect::MakeNoRet(),
StopTracking, StopTracking);
}
void InitializeClassMethodSummaries();
void InitializeMethodSummaries();
private:
void addNSObjectClsMethSummary(Selector S, const RetainSummary *Summ) {
ObjCClassMethodSummaries[S] = Summ;
}
void addNSObjectMethSummary(Selector S, const RetainSummary *Summ) {
ObjCMethodSummaries[S] = Summ;
}
void addClassMethSummary(const char* Cls, const char* name,
const RetainSummary *Summ, bool isNullary = true) {
IdentifierInfo* ClsII = &Ctx.Idents.get(Cls);
Selector S = isNullary ? GetNullarySelector(name, Ctx)
: GetUnarySelector(name, Ctx);
ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ;
}
void addInstMethSummary(const char* Cls, const char* nullaryName,
const RetainSummary *Summ) {
IdentifierInfo* ClsII = &Ctx.Idents.get(Cls);
Selector S = GetNullarySelector(nullaryName, Ctx);
ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ;
}
void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy &Summaries,
const RetainSummary *Summ, va_list argp) {
Selector S = getKeywordSelector(Ctx, argp);
Summaries[ObjCSummaryKey(ClsII, S)] = Summ;
}
void addInstMethSummary(const char* Cls, const RetainSummary * Summ, ...) {
va_list argp;
va_start(argp, Summ);
addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, argp);
va_end(argp);
}
void addClsMethSummary(const char* Cls, const RetainSummary * Summ, ...) {
va_list argp;
va_start(argp, Summ);
addMethodSummary(&Ctx.Idents.get(Cls),ObjCClassMethodSummaries, Summ, argp);
va_end(argp);
}
void addClsMethSummary(IdentifierInfo *II, const RetainSummary * Summ, ...) {
va_list argp;
va_start(argp, Summ);
addMethodSummary(II, ObjCClassMethodSummaries, Summ, argp);
va_end(argp);
}
public:
RetainSummaryManager(ASTContext &ctx, bool gcenabled, bool usesARC)
: Ctx(ctx),
GCEnabled(gcenabled),
ARCEnabled(usesARC),
AF(BPAlloc), ScratchArgs(AF.getEmptyMap()),
ObjCAllocRetE(gcenabled
? RetEffect::MakeGCNotOwned()
: (usesARC ? RetEffect::MakeNotOwned(RetEffect::ObjC)
: RetEffect::MakeOwned(RetEffect::ObjC, true))),
ObjCInitRetE(gcenabled
? RetEffect::MakeGCNotOwned()
: (usesARC ? RetEffect::MakeNotOwned(RetEffect::ObjC)
: RetEffect::MakeOwnedWhenTrackedReceiver())) {
InitializeClassMethodSummaries();
InitializeMethodSummaries();
}
const RetainSummary *getSummary(const CallEvent &Call,
ProgramStateRef State = nullptr);
const RetainSummary *getFunctionSummary(const FunctionDecl *FD);
const RetainSummary *getMethodSummary(Selector S, const ObjCInterfaceDecl *ID,
const ObjCMethodDecl *MD,
QualType RetTy,
ObjCMethodSummariesTy &CachedSummaries);
const RetainSummary *getInstanceMethodSummary(const ObjCMethodCall &M,
ProgramStateRef State);
const RetainSummary *getClassMethodSummary(const ObjCMethodCall &M) {
assert(!M.isInstanceMessage());
const ObjCInterfaceDecl *Class = M.getReceiverInterface();
return getMethodSummary(M.getSelector(), Class, M.getDecl(),
M.getResultType(), ObjCClassMethodSummaries);
}
/// getMethodSummary - This version of getMethodSummary is used to query
/// the summary for the current method being analyzed.
const RetainSummary *getMethodSummary(const ObjCMethodDecl *MD) {
const ObjCInterfaceDecl *ID = MD->getClassInterface();
Selector S = MD->getSelector();
QualType ResultTy = MD->getReturnType();
ObjCMethodSummariesTy *CachedSummaries;
if (MD->isInstanceMethod())
CachedSummaries = &ObjCMethodSummaries;
else
CachedSummaries = &ObjCClassMethodSummaries;
return getMethodSummary(S, ID, MD, ResultTy, *CachedSummaries);
}
const RetainSummary *getStandardMethodSummary(const ObjCMethodDecl *MD,
Selector S, QualType RetTy);
/// Determine if there is a special return effect for this function or method.
Optional<RetEffect> getRetEffectFromAnnotations(QualType RetTy,
const Decl *D);
void updateSummaryFromAnnotations(const RetainSummary *&Summ,
const ObjCMethodDecl *MD);
void updateSummaryFromAnnotations(const RetainSummary *&Summ,
const FunctionDecl *FD);
void updateSummaryForCall(const RetainSummary *&Summ,
const CallEvent &Call);
bool isGCEnabled() const { return GCEnabled; }
bool isARCEnabled() const { return ARCEnabled; }
bool isARCorGCEnabled() const { return GCEnabled || ARCEnabled; }
RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; }
friend class RetainSummaryTemplate;
};
// Used to avoid allocating long-term (BPAlloc'd) memory for default retain
// summaries. If a function or method looks like it has a default summary, but
// it has annotations, the annotations are added to the stack-based template
// and then copied into managed memory.
class RetainSummaryTemplate {
RetainSummaryManager &Manager;
const RetainSummary *&RealSummary;
RetainSummary ScratchSummary;
bool Accessed;
public:
RetainSummaryTemplate(const RetainSummary *&real, RetainSummaryManager &mgr)
: Manager(mgr), RealSummary(real), ScratchSummary(*real), Accessed(false) {}
~RetainSummaryTemplate() {
if (Accessed)
RealSummary = Manager.getPersistentSummary(ScratchSummary);
}
RetainSummary &operator*() {
Accessed = true;
return ScratchSummary;
}
RetainSummary *operator->() {
Accessed = true;
return &ScratchSummary;
}
};
} // end anonymous namespace
//===----------------------------------------------------------------------===//
// Implementation of checker data structures.
//===----------------------------------------------------------------------===//
ArgEffects RetainSummaryManager::getArgEffects() {
ArgEffects AE = ScratchArgs;
ScratchArgs = AF.getEmptyMap();
return AE;
}
const RetainSummary *
RetainSummaryManager::getPersistentSummary(const RetainSummary &OldSumm) {
// Unique "simple" summaries -- those without ArgEffects.
if (OldSumm.isSimple()) {
llvm::FoldingSetNodeID ID;
OldSumm.Profile(ID);
void *Pos;
CachedSummaryNode *N = SimpleSummaries.FindNodeOrInsertPos(ID, Pos);
if (!N) {
N = (CachedSummaryNode *) BPAlloc.Allocate<CachedSummaryNode>();
new (N) CachedSummaryNode(OldSumm);
SimpleSummaries.InsertNode(N, Pos);
}
return &N->getValue();
}
RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>();
new (Summ) RetainSummary(OldSumm);
return Summ;
}
//===----------------------------------------------------------------------===//
// Summary creation for functions (largely uses of Core Foundation).
//===----------------------------------------------------------------------===//
static bool isRetain(const FunctionDecl *FD, StringRef FName) {
return FName.endswith("Retain");
}
static bool isRelease(const FunctionDecl *FD, StringRef FName) {
return FName.endswith("Release");
}
static bool isAutorelease(const FunctionDecl *FD, StringRef FName) {
return FName.endswith("Autorelease");
}
static bool isMakeCollectable(const FunctionDecl *FD, StringRef FName) {
// FIXME: Remove FunctionDecl parameter.
// FIXME: Is it really okay if MakeCollectable isn't a suffix?
return FName.find("MakeCollectable") != StringRef::npos;
}
static ArgEffect getStopTrackingHardEquivalent(ArgEffect E) {
switch (E) {
case DoNothing:
case Autorelease:
case DecRefBridgedTransferred:
case IncRef:
case IncRefMsg:
case MakeCollectable:
case UnretainedOutParameter:
case RetainedOutParameter:
case MayEscape:
case StopTracking:
case StopTrackingHard:
return StopTrackingHard;
case DecRef:
case DecRefAndStopTrackingHard:
return DecRefAndStopTrackingHard;
case DecRefMsg:
case DecRefMsgAndStopTrackingHard:
return DecRefMsgAndStopTrackingHard;
case Dealloc:
return Dealloc;
}
llvm_unreachable("Unknown ArgEffect kind");
}
void RetainSummaryManager::updateSummaryForCall(const RetainSummary *&S,
const CallEvent &Call) {
if (Call.hasNonZeroCallbackArg()) {
ArgEffect RecEffect =
getStopTrackingHardEquivalent(S->getReceiverEffect());
ArgEffect DefEffect =
getStopTrackingHardEquivalent(S->getDefaultArgEffect());
ArgEffects CustomArgEffects = S->getArgEffects();
for (ArgEffects::iterator I = CustomArgEffects.begin(),
E = CustomArgEffects.end();
I != E; ++I) {
ArgEffect Translated = getStopTrackingHardEquivalent(I->second);
if (Translated != DefEffect)
ScratchArgs = AF.add(ScratchArgs, I->first, Translated);
}
RetEffect RE = RetEffect::MakeNoRetHard();
// Special cases where the callback argument CANNOT free the return value.
// This can generally only happen if we know that the callback will only be
// called when the return value is already being deallocated.
if (const SimpleFunctionCall *FC = dyn_cast<SimpleFunctionCall>(&Call)) {
if (IdentifierInfo *Name = FC->getDecl()->getIdentifier()) {
// When the CGBitmapContext is deallocated, the callback here will free
// the associated data buffer.
if (Name->isStr("CGBitmapContextCreateWithData"))
RE = S->getRetEffect();
}
}
S = getPersistentSummary(RE, RecEffect, DefEffect);
}
// Special case '[super init];' and '[self init];'
//
// Even though calling '[super init]' without assigning the result to self
// and checking if the parent returns 'nil' is a bad pattern, it is common.
// Additionally, our Self Init checker already warns about it. To avoid
// overwhelming the user with messages from both checkers, we model the case
// of '[super init]' in cases when it is not consumed by another expression
// as if the call preserves the value of 'self'; essentially, assuming it can
// never fail and return 'nil'.
// Note, we don't want to just stop tracking the value since we want the
// RetainCount checker to report leaks and use-after-free if SelfInit checker
// is turned off.
if (const ObjCMethodCall *MC = dyn_cast<ObjCMethodCall>(&Call)) {
if (MC->getMethodFamily() == OMF_init && MC->isReceiverSelfOrSuper()) {
// Check if the message is not consumed, we know it will not be used in
// an assignment, ex: "self = [super init]".
const Expr *ME = MC->getOriginExpr();
const LocationContext *LCtx = MC->getLocationContext();
ParentMap &PM = LCtx->getAnalysisDeclContext()->getParentMap();
if (!PM.isConsumedExpr(ME)) {
RetainSummaryTemplate ModifiableSummaryTemplate(S, *this);
ModifiableSummaryTemplate->setReceiverEffect(DoNothing);
ModifiableSummaryTemplate->setRetEffect(RetEffect::MakeNoRet());
}
}
}
}
const RetainSummary *
RetainSummaryManager::getSummary(const CallEvent &Call,
ProgramStateRef State) {
const RetainSummary *Summ;
switch (Call.getKind()) {
case CE_Function:
Summ = getFunctionSummary(cast<SimpleFunctionCall>(Call).getDecl());
break;
case CE_CXXMember:
case CE_CXXMemberOperator:
case CE_Block:
case CE_CXXConstructor:
case CE_CXXDestructor:
case CE_CXXAllocator:
// FIXME: These calls are currently unsupported.
return getPersistentStopSummary();
case CE_ObjCMessage: {
const ObjCMethodCall &Msg = cast<ObjCMethodCall>(Call);
if (Msg.isInstanceMessage())
Summ = getInstanceMethodSummary(Msg, State);
else
Summ = getClassMethodSummary(Msg);
break;
}
}
updateSummaryForCall(Summ, Call);
assert(Summ && "Unknown call type?");
return Summ;
}
const RetainSummary *
RetainSummaryManager::getFunctionSummary(const FunctionDecl *FD) {
// If we don't know what function we're calling, use our default summary.
if (!FD)
return getDefaultSummary();
// Look up a summary in our cache of FunctionDecls -> Summaries.
FuncSummariesTy::iterator I = FuncSummaries.find(FD);
if (I != FuncSummaries.end())
return I->second;
// No summary? Generate one.
const RetainSummary *S = nullptr;
bool AllowAnnotations = true;
do {
// We generate "stop" summaries for implicitly defined functions.
if (FD->isImplicit()) {
S = getPersistentStopSummary();
break;
}
// [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the
// function's type.
const FunctionType* FT = FD->getType()->getAs<FunctionType>();
const IdentifierInfo *II = FD->getIdentifier();
if (!II)
break;
StringRef FName = II->getName();
// Strip away preceding '_'. Doing this here will effect all the checks
// down below.
FName = FName.substr(FName.find_first_not_of('_'));
// Inspect the result type.
QualType RetTy = FT->getReturnType();
// FIXME: This should all be refactored into a chain of "summary lookup"
// filters.
assert(ScratchArgs.isEmpty());
if (FName == "pthread_create" || FName == "pthread_setspecific") {
// Part of: <rdar://problem/7299394> and <rdar://problem/11282706>.
// This will be addressed better with IPA.
S = getPersistentStopSummary();
} else if (FName == "NSMakeCollectable") {
// Handle: id NSMakeCollectable(CFTypeRef)
S = (RetTy->isObjCIdType())
? getUnarySummary(FT, cfmakecollectable)
: getPersistentStopSummary();
// The headers on OS X 10.8 use cf_consumed/ns_returns_retained,
// but we can fully model NSMakeCollectable ourselves.
AllowAnnotations = false;
} else if (FName == "CFPlugInInstanceCreate") {
S = getPersistentSummary(RetEffect::MakeNoRet());
} else if (FName == "IOBSDNameMatching" ||
FName == "IOServiceMatching" ||
FName == "IOServiceNameMatching" ||
FName == "IORegistryEntrySearchCFProperty" ||
FName == "IORegistryEntryIDMatching" ||
FName == "IOOpenFirmwarePathMatching") {
// Part of <rdar://problem/6961230>. (IOKit)
// This should be addressed using a API table.
S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true),
DoNothing, DoNothing);
} else if (FName == "IOServiceGetMatchingService" ||
FName == "IOServiceGetMatchingServices") {
// FIXES: <rdar://problem/6326900>
// This should be addressed using a API table. This strcmp is also
// a little gross, but there is no need to super optimize here.
ScratchArgs = AF.add(ScratchArgs, 1, DecRef);
S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
} else if (FName == "IOServiceAddNotification" ||
FName == "IOServiceAddMatchingNotification") {
// Part of <rdar://problem/6961230>. (IOKit)
// This should be addressed using a API table.
ScratchArgs = AF.add(ScratchArgs, 2, DecRef);
S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
} else if (FName == "CVPixelBufferCreateWithBytes") {
// FIXES: <rdar://problem/7283567>
// Eventually this can be improved by recognizing that the pixel
// buffer passed to CVPixelBufferCreateWithBytes is released via
// a callback and doing full IPA to make sure this is done correctly.
// FIXME: This function has an out parameter that returns an
// allocated object.
ScratchArgs = AF.add(ScratchArgs, 7, StopTracking);
S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
} else if (FName == "CGBitmapContextCreateWithData") {
// FIXES: <rdar://problem/7358899>
// Eventually this can be improved by recognizing that 'releaseInfo'
// passed to CGBitmapContextCreateWithData is released via
// a callback and doing full IPA to make sure this is done correctly.
ScratchArgs = AF.add(ScratchArgs, 8, StopTracking);
S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true),
DoNothing, DoNothing);
} else if (FName == "CVPixelBufferCreateWithPlanarBytes") {
// FIXES: <rdar://problem/7283567>
// Eventually this can be improved by recognizing that the pixel
// buffer passed to CVPixelBufferCreateWithPlanarBytes is released
// via a callback and doing full IPA to make sure this is done
// correctly.
ScratchArgs = AF.add(ScratchArgs, 12, StopTracking);
S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
} else if (FName == "dispatch_set_context" ||
FName == "xpc_connection_set_context") {
// <rdar://problem/11059275> - The analyzer currently doesn't have
// a good way to reason about the finalizer function for libdispatch.
// If we pass a context object that is memory managed, stop tracking it.
// <rdar://problem/13783514> - Same problem, but for XPC.
// FIXME: this hack should possibly go away once we can handle
// libdispatch and XPC finalizers.
ScratchArgs = AF.add(ScratchArgs, 1, StopTracking);
S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
} else if (FName.startswith("NSLog")) {
S = getDoNothingSummary();
} else if (FName.startswith("NS") &&
(FName.find("Insert") != StringRef::npos)) {
// Whitelist NSXXInsertXX, for example NSMapInsertIfAbsent, since they can
// be deallocated by NSMapRemove. (radar://11152419)
ScratchArgs = AF.add(ScratchArgs, 1, StopTracking);
ScratchArgs = AF.add(ScratchArgs, 2, StopTracking);
S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
}
// Did we get a summary?
if (S)
break;
if (RetTy->isPointerType()) {
// For CoreFoundation ('CF') types.
if (cocoa::isRefType(RetTy, "CF", FName)) {
if (isRetain(FD, FName)) {
S = getUnarySummary(FT, cfretain);
} else if (isAutorelease(FD, FName)) {
S = getUnarySummary(FT, cfautorelease);
// The headers use cf_consumed, but we can fully model CFAutorelease
// ourselves.
AllowAnnotations = false;
} else if (isMakeCollectable(FD, FName)) {
S = getUnarySummary(FT, cfmakecollectable);
AllowAnnotations = false;
} else {
S = getCFCreateGetRuleSummary(FD);
}
break;
}
// For CoreGraphics ('CG') types.
if (cocoa::isRefType(RetTy, "CG", FName)) {
if (isRetain(FD, FName))
S = getUnarySummary(FT, cfretain);
else
S = getCFCreateGetRuleSummary(FD);
break;
}
// For the Disk Arbitration API (DiskArbitration/DADisk.h)
if (cocoa::isRefType(RetTy, "DADisk") ||
cocoa::isRefType(RetTy, "DADissenter") ||
cocoa::isRefType(RetTy, "DASessionRef")) {
S = getCFCreateGetRuleSummary(FD);
break;
}
if (FD->hasAttr<CFAuditedTransferAttr>()) {
S = getCFCreateGetRuleSummary(FD);
break;
}
break;
}
// Check for release functions, the only kind of functions that we care
// about that don't return a pointer type.
if (FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) {
// Test for 'CGCF'.
FName = FName.substr(FName.startswith("CGCF") ? 4 : 2);
if (isRelease(FD, FName))
S = getUnarySummary(FT, cfrelease);
else {
assert (ScratchArgs.isEmpty());
// Remaining CoreFoundation and CoreGraphics functions.
// We use to assume that they all strictly followed the ownership idiom
// and that ownership cannot be transferred. While this is technically
// correct, many methods allow a tracked object to escape. For example:
//
// CFMutableDictionaryRef x = CFDictionaryCreateMutable(...);
// CFDictionaryAddValue(y, key, x);
// CFRelease(x);
// ... it is okay to use 'x' since 'y' has a reference to it
//
// We handle this and similar cases with the follow heuristic. If the
// function name contains "InsertValue", "SetValue", "AddValue",
// "AppendValue", or "SetAttribute", then we assume that arguments may
// "escape." This means that something else holds on to the object,
// allowing it be used even after its local retain count drops to 0.
ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos||
StrInStrNoCase(FName, "AddValue") != StringRef::npos ||
StrInStrNoCase(FName, "SetValue") != StringRef::npos ||
StrInStrNoCase(FName, "AppendValue") != StringRef::npos||
StrInStrNoCase(FName, "SetAttribute") != StringRef::npos)
? MayEscape : DoNothing;
S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E);
}
}
}
while (0);
// If we got all the way here without any luck, use a default summary.
if (!S)
S = getDefaultSummary();
// Annotations override defaults.
if (AllowAnnotations)
updateSummaryFromAnnotations(S, FD);
FuncSummaries[FD] = S;
return S;
}
const RetainSummary *
RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD) {
if (coreFoundation::followsCreateRule(FD))
return getCFSummaryCreateRule(FD);
return getCFSummaryGetRule(FD);
}
const RetainSummary *
RetainSummaryManager::getUnarySummary(const FunctionType* FT,
UnaryFuncKind func) {
// Sanity check that this is *really* a unary function. This can
// happen if people do weird things.
const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT);
if (!FTP || FTP->getNumParams() != 1)
return getPersistentStopSummary();
assert (ScratchArgs.isEmpty());
ArgEffect Effect;
switch (func) {
case cfretain: Effect = IncRef; break;
case cfrelease: Effect = DecRef; break;
case cfautorelease: Effect = Autorelease; break;
case cfmakecollectable: Effect = MakeCollectable; break;
}
ScratchArgs = AF.add(ScratchArgs, 0, Effect);
return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
}
const RetainSummary *
RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) {
assert (ScratchArgs.isEmpty());
return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true));
}
const RetainSummary *
RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) {
assert (ScratchArgs.isEmpty());
return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF),
DoNothing, DoNothing);
}
//===----------------------------------------------------------------------===//
// Summary creation for Selectors.
//===----------------------------------------------------------------------===//
Optional<RetEffect>
RetainSummaryManager::getRetEffectFromAnnotations(QualType RetTy,
const Decl *D) {
if (cocoa::isCocoaObjectRef(RetTy)) {
if (D->hasAttr<NSReturnsRetainedAttr>())
return ObjCAllocRetE;
if (D->hasAttr<NSReturnsNotRetainedAttr>() ||
D->hasAttr<NSReturnsAutoreleasedAttr>())
return RetEffect::MakeNotOwned(RetEffect::ObjC);
} else if (!RetTy->isPointerType()) {
return None;
}
if (D->hasAttr<CFReturnsRetainedAttr>())
return RetEffect::MakeOwned(RetEffect::CF, true);
if (D->hasAttr<CFReturnsNotRetainedAttr>())
return RetEffect::MakeNotOwned(RetEffect::CF);
return None;
}
void
RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ,
const FunctionDecl *FD) {
if (!FD)
return;
assert(Summ && "Must have a summary to add annotations to.");
RetainSummaryTemplate Template(Summ, *this);
// Effects on the parameters.
unsigned parm_idx = 0;
for (FunctionDecl::param_const_iterator pi = FD->param_begin(),
pe = FD->param_end(); pi != pe; ++pi, ++parm_idx) {
const ParmVarDecl *pd = *pi;
if (pd->hasAttr<NSConsumedAttr>())
Template->addArg(AF, parm_idx, DecRefMsg);
else if (pd->hasAttr<CFConsumedAttr>())
Template->addArg(AF, parm_idx, DecRef);
else if (pd->hasAttr<CFReturnsRetainedAttr>()) {
QualType PointeeTy = pd->getType()->getPointeeType();
if (!PointeeTy.isNull())
if (coreFoundation::isCFObjectRef(PointeeTy))
Template->addArg(AF, parm_idx, RetainedOutParameter);
} else if (pd->hasAttr<CFReturnsNotRetainedAttr>()) {
QualType PointeeTy = pd->getType()->getPointeeType();
if (!PointeeTy.isNull())
if (coreFoundation::isCFObjectRef(PointeeTy))
Template->addArg(AF, parm_idx, UnretainedOutParameter);
}
}
QualType RetTy = FD->getReturnType();
if (Optional<RetEffect> RetE = getRetEffectFromAnnotations(RetTy, FD))
Template->setRetEffect(*RetE);
}
void
RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ,
const ObjCMethodDecl *MD) {
if (!MD)
return;
assert(Summ && "Must have a valid summary to add annotations to");
RetainSummaryTemplate Template(Summ, *this);
// Effects on the receiver.
if (MD->hasAttr<NSConsumesSelfAttr>())
Template->setReceiverEffect(DecRefMsg);
// Effects on the parameters.
unsigned parm_idx = 0;
for (ObjCMethodDecl::param_const_iterator
pi=MD->param_begin(), pe=MD->param_end();
pi != pe; ++pi, ++parm_idx) {
const ParmVarDecl *pd = *pi;
if (pd->hasAttr<NSConsumedAttr>())
Template->addArg(AF, parm_idx, DecRefMsg);
else if (pd->hasAttr<CFConsumedAttr>()) {
Template->addArg(AF, parm_idx, DecRef);
} else if (pd->hasAttr<CFReturnsRetainedAttr>()) {
QualType PointeeTy = pd->getType()->getPointeeType();
if (!PointeeTy.isNull())
if (coreFoundation::isCFObjectRef(PointeeTy))
Template->addArg(AF, parm_idx, RetainedOutParameter);
} else if (pd->hasAttr<CFReturnsNotRetainedAttr>()) {
QualType PointeeTy = pd->getType()->getPointeeType();
if (!PointeeTy.isNull())
if (coreFoundation::isCFObjectRef(PointeeTy))
Template->addArg(AF, parm_idx, UnretainedOutParameter);
}
}
QualType RetTy = MD->getReturnType();
if (Optional<RetEffect> RetE = getRetEffectFromAnnotations(RetTy, MD))
Template->setRetEffect(*RetE);
}
const RetainSummary *
RetainSummaryManager::getStandardMethodSummary(const ObjCMethodDecl *MD,
Selector S, QualType RetTy) {
// Any special effects?
ArgEffect ReceiverEff = DoNothing;
RetEffect ResultEff = RetEffect::MakeNoRet();
// Check the method family, and apply any default annotations.
switch (MD ? MD->getMethodFamily() : S.getMethodFamily()) {
case OMF_None:
case OMF_initialize:
case OMF_performSelector:
// Assume all Objective-C methods follow Cocoa Memory Management rules.
// FIXME: Does the non-threaded performSelector family really belong here?
// The selector could be, say, @selector(copy).
if (cocoa::isCocoaObjectRef(RetTy))
ResultEff = RetEffect::MakeNotOwned(RetEffect::ObjC);
else if (coreFoundation::isCFObjectRef(RetTy)) {
// ObjCMethodDecl currently doesn't consider CF objects as valid return
// values for alloc, new, copy, or mutableCopy, so we have to
// double-check with the selector. This is ugly, but there aren't that
// many Objective-C methods that return CF objects, right?
if (MD) {
switch (S.getMethodFamily()) {
case OMF_alloc:
case OMF_new:
case OMF_copy:
case OMF_mutableCopy:
ResultEff = RetEffect::MakeOwned(RetEffect::CF, true);
break;
default:
ResultEff = RetEffect::MakeNotOwned(RetEffect::CF);
break;
}
} else {
ResultEff = RetEffect::MakeNotOwned(RetEffect::CF);
}
}
break;
case OMF_init:
ResultEff = ObjCInitRetE;
ReceiverEff = DecRefMsg;
break;
case OMF_alloc:
case OMF_new:
case OMF_copy:
case OMF_mutableCopy:
if (cocoa::isCocoaObjectRef(RetTy))
ResultEff = ObjCAllocRetE;
else if (coreFoundation::isCFObjectRef(RetTy))
ResultEff = RetEffect::MakeOwned(RetEffect::CF, true);
break;
case OMF_autorelease:
ReceiverEff = Autorelease;
break;
case OMF_retain:
ReceiverEff = IncRefMsg;
break;
case OMF_release:
ReceiverEff = DecRefMsg;
break;
case OMF_dealloc:
ReceiverEff = Dealloc;
break;
case OMF_self:
// -self is handled specially by the ExprEngine to propagate the receiver.
break;
case OMF_retainCount:
case OMF_finalize:
// These methods don't return objects.
break;
}
// If one of the arguments in the selector has the keyword 'delegate' we
// should stop tracking the reference count for the receiver. This is
// because the reference count is quite possibly handled by a delegate
// method.
if (S.isKeywordSelector()) {
for (unsigned i = 0, e = S.getNumArgs(); i != e; ++i) {
StringRef Slot = S.getNameForSlot(i);
if (Slot.substr(Slot.size() - 8).equals_lower("delegate")) {
if (ResultEff == ObjCInitRetE)
ResultEff = RetEffect::MakeNoRetHard();
else
ReceiverEff = StopTrackingHard;
}
}
}
if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing &&
ResultEff.getKind() == RetEffect::NoRet)
return getDefaultSummary();
return getPersistentSummary(ResultEff, ReceiverEff, MayEscape);
}
const RetainSummary *
RetainSummaryManager::getInstanceMethodSummary(const ObjCMethodCall &Msg,
ProgramStateRef State) {
const ObjCInterfaceDecl *ReceiverClass = nullptr;
// We do better tracking of the type of the object than the core ExprEngine.
// See if we have its type in our private state.
// FIXME: Eventually replace the use of state->get<RefBindings> with
// a generic API for reasoning about the Objective-C types of symbolic
// objects.
SVal ReceiverV = Msg.getReceiverSVal();
if (SymbolRef Sym = ReceiverV.getAsLocSymbol())
if (const RefVal *T = getRefBinding(State, Sym))
if (const ObjCObjectPointerType *PT =
T->getType()->getAs<ObjCObjectPointerType>())
ReceiverClass = PT->getInterfaceDecl();
// If we don't know what kind of object this is, fall back to its static type.
if (!ReceiverClass)
ReceiverClass = Msg.getReceiverInterface();
// FIXME: The receiver could be a reference to a class, meaning that
// we should use the class method.
// id x = [NSObject class];
// [x performSelector:... withObject:... afterDelay:...];
Selector S = Msg.getSelector();
const ObjCMethodDecl *Method = Msg.getDecl();
if (!Method && ReceiverClass)
Method = ReceiverClass->getInstanceMethod(S);
return getMethodSummary(S, ReceiverClass, Method, Msg.getResultType(),
ObjCMethodSummaries);
}
const RetainSummary *
RetainSummaryManager::getMethodSummary(Selector S, const ObjCInterfaceDecl *ID,
const ObjCMethodDecl *MD, QualType RetTy,
ObjCMethodSummariesTy &CachedSummaries) {
// Look up a summary in our summary cache.
const RetainSummary *Summ = CachedSummaries.find(ID, S);
if (!Summ) {
Summ = getStandardMethodSummary(MD, S, RetTy);
// Annotations override defaults.
updateSummaryFromAnnotations(Summ, MD);
// Memoize the summary.
CachedSummaries[ObjCSummaryKey(ID, S)] = Summ;
}
return Summ;
}
void RetainSummaryManager::InitializeClassMethodSummaries() {
assert(ScratchArgs.isEmpty());
// Create the [NSAssertionHandler currentHander] summary.
addClassMethSummary("NSAssertionHandler", "currentHandler",
getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC)));
// Create the [NSAutoreleasePool addObject:] summary.
ScratchArgs = AF.add(ScratchArgs, 0, Autorelease);
addClassMethSummary("NSAutoreleasePool", "addObject",
getPersistentSummary(RetEffect::MakeNoRet(),
DoNothing, Autorelease));
}
void RetainSummaryManager::InitializeMethodSummaries() {
assert (ScratchArgs.isEmpty());
// Create the "init" selector. It just acts as a pass-through for the
// receiver.
const RetainSummary *InitSumm = getPersistentSummary(ObjCInitRetE, DecRefMsg);
addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm);
// awakeAfterUsingCoder: behaves basically like an 'init' method. It
// claims the receiver and returns a retained object.
addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx),
InitSumm);
// The next methods are allocators.
const RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE);
const RetainSummary *CFAllocSumm =
getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true));
// Create the "retain" selector.
RetEffect NoRet = RetEffect::MakeNoRet();
const RetainSummary *Summ = getPersistentSummary(NoRet, IncRefMsg);
addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ);
// Create the "release" selector.
Summ = getPersistentSummary(NoRet, DecRefMsg);
addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ);
// Create the -dealloc summary.
Summ = getPersistentSummary(NoRet, Dealloc);
addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ);
// Create the "autorelease" selector.
Summ = getPersistentSummary(NoRet, Autorelease);
addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ);
// For NSWindow, allocated objects are (initially) self-owned.
// FIXME: For now we opt for false negatives with NSWindow, as these objects
// self-own themselves. However, they only do this once they are displayed.
// Thus, we need to track an NSWindow's display status.
// This is tracked in <rdar://problem/6062711>.
// See also http://llvm.org/bugs/show_bug.cgi?id=3714.
const RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(),
StopTracking,
StopTracking);
addClassMethSummary("NSWindow", "alloc", NoTrackYet);
// For NSPanel (which subclasses NSWindow), allocated objects are not
// self-owned.
// FIXME: For now we don't track NSPanels. object for the same reason
// as for NSWindow objects.
addClassMethSummary("NSPanel", "alloc", NoTrackYet);
// For NSNull, objects returned by +null are singletons that ignore
// retain/release semantics. Just don't track them.
// <rdar://problem/12858915>
addClassMethSummary("NSNull", "null", NoTrackYet);
// Don't track allocated autorelease pools, as it is okay to prematurely
// exit a method.
addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet);
addClassMethSummary("NSAutoreleasePool", "allocWithZone", NoTrackYet, false);
addClassMethSummary("NSAutoreleasePool", "new", NoTrackYet);
// Create summaries QCRenderer/QCView -createSnapShotImageOfType:
addInstMethSummary("QCRenderer", AllocSumm,
"createSnapshotImageOfType", nullptr);
addInstMethSummary("QCView", AllocSumm,
"createSnapshotImageOfType", nullptr);
// Create summaries for CIContext, 'createCGImage' and
// 'createCGLayerWithSize'. These objects are CF objects, and are not
// automatically garbage collected.
addInstMethSummary("CIContext", CFAllocSumm,
"createCGImage", "fromRect", nullptr);
addInstMethSummary("CIContext", CFAllocSumm, "createCGImage", "fromRect",
"format", "colorSpace", nullptr);
addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", "info",
nullptr);
}
//===----------------------------------------------------------------------===//
// Error reporting.
//===----------------------------------------------------------------------===//
namespace {
typedef llvm::DenseMap<const ExplodedNode *, const RetainSummary *>
SummaryLogTy;
//===-------------===//
// Bug Descriptions. //
//===-------------===//
class CFRefBug : public BugType {
protected:
CFRefBug(const CheckerBase *checker, StringRef name)
: BugType(checker, name, categories::MemoryCoreFoundationObjectiveC) {}
public:
// FIXME: Eventually remove.
virtual const char *getDescription() const = 0;
virtual bool isLeak() const { return false; }
};
class UseAfterRelease : public CFRefBug {
public:
UseAfterRelease(const CheckerBase *checker)
: CFRefBug(checker, "Use-after-release") {}
const char *getDescription() const override {
return "Reference-counted object is used after it is released";
}
};
class BadRelease : public CFRefBug {
public:
BadRelease(const CheckerBase *checker) : CFRefBug(checker, "Bad release") {}
const char *getDescription() const override {
return "Incorrect decrement of the reference count of an object that is "
"not owned at this point by the caller";
}
};
class DeallocGC : public CFRefBug {
public:
DeallocGC(const CheckerBase *checker)
: CFRefBug(checker, "-dealloc called while using garbage collection") {}
const char *getDescription() const override {
return "-dealloc called while using garbage collection";
}
};
class DeallocNotOwned : public CFRefBug {
public:
DeallocNotOwned(const CheckerBase *checker)
: CFRefBug(checker, "-dealloc sent to non-exclusively owned object") {}
const char *getDescription() const override {
return "-dealloc sent to object that may be referenced elsewhere";
}
};
class OverAutorelease : public CFRefBug {
public:
OverAutorelease(const CheckerBase *checker)
: CFRefBug(checker, "Object autoreleased too many times") {}
const char *getDescription() const override {
return "Object autoreleased too many times";
}
};
class ReturnedNotOwnedForOwned : public CFRefBug {
public:
ReturnedNotOwnedForOwned(const CheckerBase *checker)
: CFRefBug(checker, "Method should return an owned object") {}
const char *getDescription() const override {
return "Object with a +0 retain count returned to caller where a +1 "
"(owning) retain count is expected";
}
};
class Leak : public CFRefBug {
public:
Leak(const CheckerBase *checker, StringRef name) : CFRefBug(checker, name) {
// Leaks should not be reported if they are post-dominated by a sink.
setSuppressOnSink(true);
}
const char *getDescription() const override { return ""; }
bool isLeak() const override { return true; }
};
//===---------===//
// Bug Reports. //
//===---------===//
class CFRefReportVisitor : public BugReporterVisitorImpl<CFRefReportVisitor> {
protected:
SymbolRef Sym;
const SummaryLogTy &SummaryLog;
bool GCEnabled;
public:
CFRefReportVisitor(SymbolRef sym, bool gcEnabled, const SummaryLogTy &log)
: Sym(sym), SummaryLog(log), GCEnabled(gcEnabled) {}
void Profile(llvm::FoldingSetNodeID &ID) const override {
static int x = 0;
ID.AddPointer(&x);
ID.AddPointer(Sym);
}
PathDiagnosticPiece *VisitNode(const ExplodedNode *N,
const ExplodedNode *PrevN,
BugReporterContext &BRC,
BugReport &BR) override;
std::unique_ptr<PathDiagnosticPiece> getEndPath(BugReporterContext &BRC,
const ExplodedNode *N,
BugReport &BR) override;
};
class CFRefLeakReportVisitor : public CFRefReportVisitor {
public:
CFRefLeakReportVisitor(SymbolRef sym, bool GCEnabled,
const SummaryLogTy &log)
: CFRefReportVisitor(sym, GCEnabled, log) {}
std::unique_ptr<PathDiagnosticPiece> getEndPath(BugReporterContext &BRC,
const ExplodedNode *N,
BugReport &BR) override;
std::unique_ptr<BugReporterVisitor> clone() const override {
// The curiously-recurring template pattern only works for one level of
// subclassing. Rather than make a new template base for
// CFRefReportVisitor, we simply override clone() to do the right thing.
// This could be trouble someday if BugReporterVisitorImpl is ever
// used for something else besides a convenient implementation of clone().
return llvm::make_unique<CFRefLeakReportVisitor>(*this);
}
};
class CFRefReport : public BugReport {
void addGCModeDescription(const LangOptions &LOpts, bool GCEnabled);
public:
CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled,
const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym,
bool registerVisitor = true)
: BugReport(D, D.getDescription(), n) {
if (registerVisitor)
addVisitor(llvm::make_unique<CFRefReportVisitor>(sym, GCEnabled, Log));
addGCModeDescription(LOpts, GCEnabled);
}
CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled,
const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym,
StringRef endText)
: BugReport(D, D.getDescription(), endText, n) {
addVisitor(llvm::make_unique<CFRefReportVisitor>(sym, GCEnabled, Log));
addGCModeDescription(LOpts, GCEnabled);
}
llvm::iterator_range<ranges_iterator> getRanges() override {
const CFRefBug& BugTy = static_cast<CFRefBug&>(getBugType());
if (!BugTy.isLeak())
return BugReport::getRanges();
return llvm::make_range(ranges_iterator(), ranges_iterator());
}
};
class CFRefLeakReport : public CFRefReport {
const MemRegion* AllocBinding;
public:
CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled,
const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym,
CheckerContext &Ctx,
bool IncludeAllocationLine);
PathDiagnosticLocation getLocation(const SourceManager &SM) const override {
assert(Location.isValid());
return Location;
}
};
} // end anonymous namespace
void CFRefReport::addGCModeDescription(const LangOptions &LOpts,
bool GCEnabled) {
const char *GCModeDescription = nullptr;
switch (LOpts.getGC()) {
case LangOptions::GCOnly:
assert(GCEnabled);
GCModeDescription = "Code is compiled to only use garbage collection";
break;
case LangOptions::NonGC:
assert(!GCEnabled);
GCModeDescription = "Code is compiled to use reference counts";
break;
case LangOptions::HybridGC:
if (GCEnabled) {
GCModeDescription = "Code is compiled to use either garbage collection "
"(GC) or reference counts (non-GC). The bug occurs "
"with GC enabled";
break;
} else {
GCModeDescription = "Code is compiled to use either garbage collection "
"(GC) or reference counts (non-GC). The bug occurs "
"in non-GC mode";
break;
}
}
assert(GCModeDescription && "invalid/unknown GC mode");
addExtraText(GCModeDescription);
}
static bool isNumericLiteralExpression(const Expr *E) {
// FIXME: This set of cases was copied from SemaExprObjC.
return isa<IntegerLiteral>(E) ||
isa<CharacterLiteral>(E) ||
isa<FloatingLiteral>(E) ||
isa<ObjCBoolLiteralExpr>(E) ||
isa<CXXBoolLiteralExpr>(E);
}
/// Returns true if this stack frame is for an Objective-C method that is a
/// property getter or setter whose body has been synthesized by the analyzer.
static bool isSynthesizedAccessor(const StackFrameContext *SFC) {
auto Method = dyn_cast_or_null<ObjCMethodDecl>(SFC->getDecl());
if (!Method || !Method->isPropertyAccessor())
return false;
return SFC->getAnalysisDeclContext()->isBodyAutosynthesized();
}
PathDiagnosticPiece *CFRefReportVisitor::VisitNode(const ExplodedNode *N,
const ExplodedNode *PrevN,
BugReporterContext &BRC,
BugReport &BR) {
// FIXME: We will eventually need to handle non-statement-based events
// (__attribute__((cleanup))).
if (!N->getLocation().getAs<StmtPoint>())
return nullptr;
// Check if the type state has changed.
ProgramStateRef PrevSt = PrevN->getState();
ProgramStateRef CurrSt = N->getState();
const LocationContext *LCtx = N->getLocationContext();
const RefVal* CurrT = getRefBinding(CurrSt, Sym);
if (!CurrT) return nullptr;
const RefVal &CurrV = *CurrT;
const RefVal *PrevT = getRefBinding(PrevSt, Sym);
// Create a string buffer to constain all the useful things we want
// to tell the user.
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
// This is the allocation site since the previous node had no bindings
// for this symbol.
if (!PrevT) {
const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
if (isa<ObjCIvarRefExpr>(S) &&
isSynthesizedAccessor(LCtx->getCurrentStackFrame())) {
S = LCtx->getCurrentStackFrame()->getCallSite();
}
if (isa<ObjCArrayLiteral>(S)) {
os << "NSArray literal is an object with a +0 retain count";
}
else if (isa<ObjCDictionaryLiteral>(S)) {
os << "NSDictionary literal is an object with a +0 retain count";
}
else if (const ObjCBoxedExpr *BL = dyn_cast<ObjCBoxedExpr>(S)) {
if (isNumericLiteralExpression(BL->getSubExpr()))
os << "NSNumber literal is an object with a +0 retain count";
else {
const ObjCInterfaceDecl *BoxClass = nullptr;
if (const ObjCMethodDecl *Method = BL->getBoxingMethod())
BoxClass = Method->getClassInterface();
// We should always be able to find the boxing class interface,
// but consider this future-proofing.
if (BoxClass)
os << *BoxClass << " b";
else
os << "B";
os << "oxed expression produces an object with a +0 retain count";
}
}
else if (isa<ObjCIvarRefExpr>(S)) {
os << "Object loaded from instance variable";
}
else {
if (const CallExpr *CE = dyn_cast<CallExpr>(S)) {
// Get the name of the callee (if it is available).
SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee(), LCtx);
if (const FunctionDecl *FD = X.getAsFunctionDecl())
os << "Call to function '" << *FD << '\'';
else
os << "function call";
}
else {
assert(isa<ObjCMessageExpr>(S));
CallEventManager &Mgr = CurrSt->getStateManager().getCallEventManager();
CallEventRef<ObjCMethodCall> Call
= Mgr.getObjCMethodCall(cast<ObjCMessageExpr>(S), CurrSt, LCtx);
switch (Call->getMessageKind()) {
case OCM_Message:
os << "Method";
break;
case OCM_PropertyAccess:
os << "Property";
break;
case OCM_Subscript:
os << "Subscript";
break;
}
}
if (CurrV.getObjKind() == RetEffect::CF) {
os << " returns a Core Foundation object with a ";
}
else {
assert (CurrV.getObjKind() == RetEffect::ObjC);
os << " returns an Objective-C object with a ";
}
if (CurrV.isOwned()) {
os << "+1 retain count";
if (GCEnabled) {
assert(CurrV.getObjKind() == RetEffect::CF);
os << ". "
"Core Foundation objects are not automatically garbage collected.";
}
}
else {
assert (CurrV.isNotOwned());
os << "+0 retain count";
}
}
PathDiagnosticLocation Pos(S, BRC.getSourceManager(),
N->getLocationContext());
return new PathDiagnosticEventPiece(Pos, os.str());
}
// Gather up the effects that were performed on the object at this
// program point
SmallVector<ArgEffect, 2> AEffects;
const ExplodedNode *OrigNode = BRC.getNodeResolver().getOriginalNode(N);
if (const RetainSummary *Summ = SummaryLog.lookup(OrigNode)) {
// We only have summaries attached to nodes after evaluating CallExpr and
// ObjCMessageExprs.
const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
if (const CallExpr *CE = dyn_cast<CallExpr>(S)) {
// Iterate through the parameter expressions and see if the symbol
// was ever passed as an argument.
unsigned i = 0;
for (CallExpr::const_arg_iterator AI=CE->arg_begin(), AE=CE->arg_end();
AI!=AE; ++AI, ++i) {
// Retrieve the value of the argument. Is it the symbol
// we are interested in?
if (CurrSt->getSValAsScalarOrLoc(*AI, LCtx).getAsLocSymbol() != Sym)
continue;
// We have an argument. Get the effect!
AEffects.push_back(Summ->getArg(i));
}
}
else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) {
if (const Expr *receiver = ME->getInstanceReceiver())
if (CurrSt->getSValAsScalarOrLoc(receiver, LCtx)
.getAsLocSymbol() == Sym) {
// The symbol we are tracking is the receiver.
AEffects.push_back(Summ->getReceiverEffect());
}
}
}
do {
// Get the previous type state.
RefVal PrevV = *PrevT;
// Specially handle -dealloc.
if (!GCEnabled && std::find(AEffects.begin(), AEffects.end(), Dealloc) !=
AEffects.end()) {
// Determine if the object's reference count was pushed to zero.
assert(!PrevV.hasSameState(CurrV) && "The state should have changed.");
// We may not have transitioned to 'release' if we hit an error.
// This case is handled elsewhere.
if (CurrV.getKind() == RefVal::Released) {
assert(CurrV.getCombinedCounts() == 0);
os << "Object released by directly sending the '-dealloc' message";
break;
}
}
// Specially handle CFMakeCollectable and friends.
if (std::find(AEffects.begin(), AEffects.end(), MakeCollectable) !=
AEffects.end()) {
// Get the name of the function.
const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
SVal X =
CurrSt->getSValAsScalarOrLoc(cast<CallExpr>(S)->getCallee(), LCtx);
const FunctionDecl *FD = X.getAsFunctionDecl();
if (GCEnabled) {
// Determine if the object's reference count was pushed to zero.
assert(!PrevV.hasSameState(CurrV) && "The state should have changed.");
os << "In GC mode a call to '" << *FD
<< "' decrements an object's retain count and registers the "
"object with the garbage collector. ";
if (CurrV.getKind() == RefVal::Released) {
assert(CurrV.getCount() == 0);
os << "Since it now has a 0 retain count the object can be "
"automatically collected by the garbage collector.";
}
else
os << "An object must have a 0 retain count to be garbage collected. "
"After this call its retain count is +" << CurrV.getCount()
<< '.';
}
else
os << "When GC is not enabled a call to '" << *FD
<< "' has no effect on its argument.";
// Nothing more to say.
break;
}
// Determine if the typestate has changed.
if (!PrevV.hasSameState(CurrV))
switch (CurrV.getKind()) {
case RefVal::Owned:
case RefVal::NotOwned:
if (PrevV.getCount() == CurrV.getCount()) {
// Did an autorelease message get sent?
if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount())
return nullptr;
assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount());
os << "Object autoreleased";
break;
}
if (PrevV.getCount() > CurrV.getCount())
os << "Reference count decremented.";
else
os << "Reference count incremented.";
if (unsigned Count = CurrV.getCount())
os << " The object now has a +" << Count << " retain count.";
if (PrevV.getKind() == RefVal::Released) {
assert(GCEnabled && CurrV.getCount() > 0);
os << " The object is not eligible for garbage collection until "
"the retain count reaches 0 again.";
}
break;
case RefVal::Released:
if (CurrV.getIvarAccessHistory() ==
RefVal::IvarAccessHistory::ReleasedAfterDirectAccess &&
CurrV.getIvarAccessHistory() != PrevV.getIvarAccessHistory()) {
os << "Strong instance variable relinquished. ";
}
os << "Object released.";
break;
case RefVal::ReturnedOwned:
// Autoreleases can be applied after marking a node ReturnedOwned.
if (CurrV.getAutoreleaseCount())
return nullptr;
os << "Object returned to caller as an owning reference (single "
"retain count transferred to caller)";
break;
case RefVal::ReturnedNotOwned:
os << "Object returned to caller with a +0 retain count";
break;
default:
return nullptr;
}
// Emit any remaining diagnostics for the argument effects (if any).
for (SmallVectorImpl<ArgEffect>::iterator I=AEffects.begin(),
E=AEffects.end(); I != E; ++I) {
// A bunch of things have alternate behavior under GC.
if (GCEnabled)
switch (*I) {
default: break;
case Autorelease:
os << "In GC mode an 'autorelease' has no effect.";
continue;
case IncRefMsg:
os << "In GC mode the 'retain' message has no effect.";
continue;
case DecRefMsg:
os << "In GC mode the 'release' message has no effect.";
continue;
}
}
} while (0);
if (os.str().empty())
return nullptr; // We have nothing to say!
const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
PathDiagnosticLocation Pos(S, BRC.getSourceManager(),
N->getLocationContext());
PathDiagnosticPiece *P = new PathDiagnosticEventPiece(Pos, os.str());
// Add the range by scanning the children of the statement for any bindings
// to Sym.
for (const Stmt *Child : S->children())
if (const Expr *Exp = dyn_cast_or_null<Expr>(Child))
if (CurrSt->getSValAsScalarOrLoc(Exp, LCtx).getAsLocSymbol() == Sym) {
P->addRange(Exp->getSourceRange());
break;
}
return P;
}
namespace {
// Find the first node in the current function context that referred to the
// tracked symbol and the memory location that value was stored to. Note, the
// value is only reported if the allocation occurred in the same function as
// the leak. The function can also return a location context, which should be
// treated as interesting.
struct AllocationInfo {
const ExplodedNode* N;
const MemRegion *R;
const LocationContext *InterestingMethodContext;
AllocationInfo(const ExplodedNode *InN,
const MemRegion *InR,
const LocationContext *InInterestingMethodContext) :
N(InN), R(InR), InterestingMethodContext(InInterestingMethodContext) {}
};
} // end anonymous namespace
static AllocationInfo
GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N,
SymbolRef Sym) {
const ExplodedNode *AllocationNode = N;
const ExplodedNode *AllocationNodeInCurrentOrParentContext = N;
const MemRegion *FirstBinding = nullptr;
const LocationContext *LeakContext = N->getLocationContext();
// The location context of the init method called on the leaked object, if
// available.
const LocationContext *InitMethodContext = nullptr;
while (N) {
ProgramStateRef St = N->getState();
const LocationContext *NContext = N->getLocationContext();
if (!getRefBinding(St, Sym))
break;
StoreManager::FindUniqueBinding FB(Sym);
StateMgr.iterBindings(St, FB);
if (FB) {
const MemRegion *R = FB.getRegion();
const VarRegion *VR = R->getBaseRegion()->getAs<VarRegion>();
// Do not show local variables belonging to a function other than
// where the error is reported.
if (!VR || VR->getStackFrame() == LeakContext->getCurrentStackFrame())
FirstBinding = R;
}
// AllocationNode is the last node in which the symbol was tracked.
AllocationNode = N;
// AllocationNodeInCurrentContext, is the last node in the current or
// parent context in which the symbol was tracked.
//
// Note that the allocation site might be in the parent conext. For example,
// the case where an allocation happens in a block that captures a reference
// to it and that reference is overwritten/dropped by another call to
// the block.
if (NContext == LeakContext || NContext->isParentOf(LeakContext))
AllocationNodeInCurrentOrParentContext = N;
// Find the last init that was called on the given symbol and store the
// init method's location context.
if (!InitMethodContext)
if (Optional<CallEnter> CEP = N->getLocation().getAs<CallEnter>()) {
const Stmt *CE = CEP->getCallExpr();
if (const ObjCMessageExpr *ME = dyn_cast_or_null<ObjCMessageExpr>(CE)) {
const Stmt *RecExpr = ME->getInstanceReceiver();
if (RecExpr) {
SVal RecV = St->getSVal(RecExpr, NContext);
if (ME->getMethodFamily() == OMF_init && RecV.getAsSymbol() == Sym)
InitMethodContext = CEP->getCalleeContext();
}
}
}
N = N->pred_empty() ? nullptr : *(N->pred_begin());
}
// If we are reporting a leak of the object that was allocated with alloc,
// mark its init method as interesting.
const LocationContext *InterestingMethodContext = nullptr;
if (InitMethodContext) {
const ProgramPoint AllocPP = AllocationNode->getLocation();
if (Optional<StmtPoint> SP = AllocPP.getAs<StmtPoint>())
if (const ObjCMessageExpr *ME = SP->getStmtAs<ObjCMessageExpr>())
if (ME->getMethodFamily() == OMF_alloc)
InterestingMethodContext = InitMethodContext;
}
// If allocation happened in a function different from the leak node context,
// do not report the binding.
assert(N && "Could not find allocation node");
if (N->getLocationContext() != LeakContext) {
FirstBinding = nullptr;
}
return AllocationInfo(AllocationNodeInCurrentOrParentContext,
FirstBinding,
InterestingMethodContext);
}
std::unique_ptr<PathDiagnosticPiece>
CFRefReportVisitor::getEndPath(BugReporterContext &BRC,
const ExplodedNode *EndN, BugReport &BR) {
BR.markInteresting(Sym);
return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR);
}
std::unique_ptr<PathDiagnosticPiece>
CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC,
const ExplodedNode *EndN, BugReport &BR) {
// Tell the BugReporterContext to report cases when the tracked symbol is
// assigned to different variables, etc.
BR.markInteresting(Sym);
// We are reporting a leak. Walk up the graph to get to the first node where
// the symbol appeared, and also get the first VarDecl that tracked object
// is stored to.
AllocationInfo AllocI =
GetAllocationSite(BRC.getStateManager(), EndN, Sym);
const MemRegion* FirstBinding = AllocI.R;
BR.markInteresting(AllocI.InterestingMethodContext);
SourceManager& SM = BRC.getSourceManager();
// Compute an actual location for the leak. Sometimes a leak doesn't
// occur at an actual statement (e.g., transition between blocks; end
// of function) so we need to walk the graph and compute a real location.
const ExplodedNode *LeakN = EndN;
PathDiagnosticLocation L = PathDiagnosticLocation::createEndOfPath(LeakN, SM);
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
os << "Object leaked: ";
if (FirstBinding) {
os << "object allocated and stored into '"
<< FirstBinding->getString() << '\'';
}
else
os << "allocated object";
// Get the retain count.
const RefVal* RV = getRefBinding(EndN->getState(), Sym);
assert(RV);
if (RV->getKind() == RefVal::ErrorLeakReturned) {
// FIXME: Per comments in rdar://6320065, "create" only applies to CF
// objects. Only "copy", "alloc", "retain" and "new" transfer ownership
// to the caller for NS objects.
const Decl *D = &EndN->getCodeDecl();
os << (isa<ObjCMethodDecl>(D) ? " is returned from a method "
: " is returned from a function ");
if (D->hasAttr<CFReturnsNotRetainedAttr>())
os << "that is annotated as CF_RETURNS_NOT_RETAINED";
else if (D->hasAttr<NSReturnsNotRetainedAttr>())
os << "that is annotated as NS_RETURNS_NOT_RETAINED";
else {
if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
os << "whose name ('" << MD->getSelector().getAsString()
<< "') does not start with 'copy', 'mutableCopy', 'alloc' or 'new'."
" This violates the naming convention rules"
" given in the Memory Management Guide for Cocoa";
}
else {
const FunctionDecl *FD = cast<FunctionDecl>(D);
os << "whose name ('" << *FD
<< "') does not contain 'Copy' or 'Create'. This violates the naming"
" convention rules given in the Memory Management Guide for Core"
" Foundation";
}
}
}
else if (RV->getKind() == RefVal::ErrorGCLeakReturned) {
const ObjCMethodDecl &MD = cast<ObjCMethodDecl>(EndN->getCodeDecl());
os << " and returned from method '" << MD.getSelector().getAsString()
<< "' is potentially leaked when using garbage collection. Callers "
"of this method do not expect a returned object with a +1 retain "
"count since they expect the object to be managed by the garbage "
"collector";
}
else
os << " is not referenced later in this execution path and has a retain "
"count of +" << RV->getCount();
return llvm::make_unique<PathDiagnosticEventPiece>(L, os.str());
}
CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts,
bool GCEnabled, const SummaryLogTy &Log,
ExplodedNode *n, SymbolRef sym,
CheckerContext &Ctx,
bool IncludeAllocationLine)
: CFRefReport(D, LOpts, GCEnabled, Log, n, sym, false) {
// Most bug reports are cached at the location where they occurred.
// With leaks, we want to unique them by the location where they were
// allocated, and only report a single path. To do this, we need to find
// the allocation site of a piece of tracked memory, which we do via a
// call to GetAllocationSite. This will walk the ExplodedGraph backwards.
// Note that this is *not* the trimmed graph; we are guaranteed, however,
// that all ancestor nodes that represent the allocation site have the
// same SourceLocation.
const ExplodedNode *AllocNode = nullptr;
const SourceManager& SMgr = Ctx.getSourceManager();
AllocationInfo AllocI =
GetAllocationSite(Ctx.getStateManager(), getErrorNode(), sym);
AllocNode = AllocI.N;
AllocBinding = AllocI.R;
markInteresting(AllocI.InterestingMethodContext);
// Get the SourceLocation for the allocation site.
// FIXME: This will crash the analyzer if an allocation comes from an
// implicit call (ex: a destructor call).
// (Currently there are no such allocations in Cocoa, though.)
const Stmt *AllocStmt = nullptr;
ProgramPoint P = AllocNode->getLocation();
if (Optional<CallExitEnd> Exit = P.getAs<CallExitEnd>())
AllocStmt = Exit->getCalleeContext()->getCallSite();
else
AllocStmt = P.castAs<PostStmt>().getStmt();
assert(AllocStmt && "Cannot find allocation statement");
PathDiagnosticLocation AllocLocation =
PathDiagnosticLocation::createBegin(AllocStmt, SMgr,
AllocNode->getLocationContext());
Location = AllocLocation;
// Set uniqieing info, which will be used for unique the bug reports. The
// leaks should be uniqued on the allocation site.
UniqueingLocation = AllocLocation;
UniqueingDecl = AllocNode->getLocationContext()->getDecl();
// Fill in the description of the bug.
Description.clear();
llvm::raw_string_ostream os(Description);
os << "Potential leak ";
if (GCEnabled)
os << "(when using garbage collection) ";
os << "of an object";
if (AllocBinding) {
os << " stored into '" << AllocBinding->getString() << '\'';
if (IncludeAllocationLine) {
FullSourceLoc SL(AllocStmt->getLocStart(), Ctx.getSourceManager());
os << " (allocated on line " << SL.getSpellingLineNumber() << ")";
}
}
addVisitor(llvm::make_unique<CFRefLeakReportVisitor>(sym, GCEnabled, Log));
}
//===----------------------------------------------------------------------===//
// Main checker logic.
//===----------------------------------------------------------------------===//
namespace {
class RetainCountChecker
: public Checker< check::Bind,
check::DeadSymbols,
check::EndAnalysis,
check::EndFunction,
check::PostStmt<BlockExpr>,
check::PostStmt<CastExpr>,
check::PostStmt<ObjCArrayLiteral>,
check::PostStmt<ObjCDictionaryLiteral>,
check::PostStmt<ObjCBoxedExpr>,
check::PostStmt<ObjCIvarRefExpr>,
check::PostCall,
check::PreStmt<ReturnStmt>,
check::RegionChanges,
eval::Assume,
eval::Call > {
mutable std::unique_ptr<CFRefBug> useAfterRelease, releaseNotOwned;
mutable std::unique_ptr<CFRefBug> deallocGC, deallocNotOwned;
mutable std::unique_ptr<CFRefBug> overAutorelease, returnNotOwnedForOwned;
mutable std::unique_ptr<CFRefBug> leakWithinFunction, leakAtReturn;
mutable std::unique_ptr<CFRefBug> leakWithinFunctionGC, leakAtReturnGC;
typedef llvm::DenseMap<SymbolRef, const CheckerProgramPointTag *> SymbolTagMap;
// This map is only used to ensure proper deletion of any allocated tags.
mutable SymbolTagMap DeadSymbolTags;
mutable std::unique_ptr<RetainSummaryManager> Summaries;
mutable std::unique_ptr<RetainSummaryManager> SummariesGC;
mutable SummaryLogTy SummaryLog;
mutable bool ShouldResetSummaryLog;
/// Optional setting to indicate if leak reports should include
/// the allocation line.
mutable bool IncludeAllocationLine;
public:
RetainCountChecker(AnalyzerOptions &AO)
: ShouldResetSummaryLog(false),
IncludeAllocationLine(shouldIncludeAllocationSiteInLeakDiagnostics(AO)) {}
~RetainCountChecker() override { DeleteContainerSeconds(DeadSymbolTags); }
void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR,
ExprEngine &Eng) const {
// FIXME: This is a hack to make sure the summary log gets cleared between
// analyses of different code bodies.
//
// Why is this necessary? Because a checker's lifetime is tied to a
// translation unit, but an ExplodedGraph's lifetime is just a code body.
// Once in a blue moon, a new ExplodedNode will have the same address as an
// old one with an associated summary, and the bug report visitor gets very
// confused. (To make things worse, the summary lifetime is currently also
// tied to a code body, so we get a crash instead of incorrect results.)
//
// Why is this a bad solution? Because if the lifetime of the ExplodedGraph
// changes, things will start going wrong again. Really the lifetime of this
// log needs to be tied to either the specific nodes in it or the entire
// ExplodedGraph, not to a specific part of the code being analyzed.
//
// (Also, having stateful local data means that the same checker can't be
// used from multiple threads, but a lot of checkers have incorrect
// assumptions about that anyway. So that wasn't a priority at the time of
// this fix.)
//
// This happens at the end of analysis, but bug reports are emitted /after/
// this point. So we can't just clear the summary log now. Instead, we mark
// that the next time we access the summary log, it should be cleared.
// If we never reset the summary log during /this/ code body analysis,
// there were no new summaries. There might still have been summaries from
// the /last/ analysis, so clear them out to make sure the bug report
// visitors don't get confused.
if (ShouldResetSummaryLog)
SummaryLog.clear();
ShouldResetSummaryLog = !SummaryLog.empty();
}
CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts,
bool GCEnabled) const {
if (GCEnabled) {
if (!leakWithinFunctionGC)
leakWithinFunctionGC.reset(new Leak(this, "Leak of object when using "
"garbage collection"));
return leakWithinFunctionGC.get();
} else {
if (!leakWithinFunction) {
if (LOpts.getGC() == LangOptions::HybridGC) {
leakWithinFunction.reset(new Leak(this,
"Leak of object when not using "
"garbage collection (GC) in "
"dual GC/non-GC code"));
} else {
leakWithinFunction.reset(new Leak(this, "Leak"));
}
}
return leakWithinFunction.get();
}
}
CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts, bool GCEnabled) const {
if (GCEnabled) {
if (!leakAtReturnGC)
leakAtReturnGC.reset(new Leak(this,
"Leak of returned object when using "
"garbage collection"));
return leakAtReturnGC.get();
} else {
if (!leakAtReturn) {
if (LOpts.getGC() == LangOptions::HybridGC) {
leakAtReturn.reset(new Leak(this,
"Leak of returned object when not using "
"garbage collection (GC) in dual "
"GC/non-GC code"));
} else {
leakAtReturn.reset(new Leak(this, "Leak of returned object"));
}
}
return leakAtReturn.get();
}
}
RetainSummaryManager &getSummaryManager(ASTContext &Ctx,
bool GCEnabled) const {
// FIXME: We don't support ARC being turned on and off during one analysis.
// (nor, for that matter, do we support changing ASTContexts)
bool ARCEnabled = (bool)Ctx.getLangOpts().ObjCAutoRefCount;
if (GCEnabled) {
if (!SummariesGC)
SummariesGC.reset(new RetainSummaryManager(Ctx, true, ARCEnabled));
else
assert(SummariesGC->isARCEnabled() == ARCEnabled);
return *SummariesGC;
} else {
if (!Summaries)
Summaries.reset(new RetainSummaryManager(Ctx, false, ARCEnabled));
else
assert(Summaries->isARCEnabled() == ARCEnabled);
return *Summaries;
}
}
RetainSummaryManager &getSummaryManager(CheckerContext &C) const {
return getSummaryManager(C.getASTContext(), C.isObjCGCEnabled());
}
void printState(raw_ostream &Out, ProgramStateRef State,
const char *NL, const char *Sep) const override;
void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const;
void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const;
void checkPostStmt(const CastExpr *CE, CheckerContext &C) const;
void checkPostStmt(const ObjCArrayLiteral *AL, CheckerContext &C) const;
void checkPostStmt(const ObjCDictionaryLiteral *DL, CheckerContext &C) const;
void checkPostStmt(const ObjCBoxedExpr *BE, CheckerContext &C) const;
void checkPostStmt(const ObjCIvarRefExpr *IRE, CheckerContext &C) const;
void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
void checkSummary(const RetainSummary &Summ, const CallEvent &Call,
CheckerContext &C) const;
void processSummaryOfInlined(const RetainSummary &Summ,
const CallEvent &Call,
CheckerContext &C) const;
bool evalCall(const CallExpr *CE, CheckerContext &C) const;
ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond,
bool Assumption) const;
ProgramStateRef
checkRegionChanges(ProgramStateRef state,
const InvalidatedSymbols *invalidated,
ArrayRef<const MemRegion *> ExplicitRegions,
ArrayRef<const MemRegion *> Regions,
const CallEvent *Call) const;
bool wantsRegionChangeUpdate(ProgramStateRef state) const {
return true;
}
void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const;
void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C,
ExplodedNode *Pred, RetEffect RE, RefVal X,
SymbolRef Sym, ProgramStateRef state) const;
void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const;
void checkEndFunction(CheckerContext &C) const;
ProgramStateRef updateSymbol(ProgramStateRef state, SymbolRef sym,
RefVal V, ArgEffect E, RefVal::Kind &hasErr,
CheckerContext &C) const;
void processNonLeakError(ProgramStateRef St, SourceRange ErrorRange,
RefVal::Kind ErrorKind, SymbolRef Sym,
CheckerContext &C) const;
void processObjCLiterals(CheckerContext &C, const Expr *Ex) const;
const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const;
ProgramStateRef handleSymbolDeath(ProgramStateRef state,
SymbolRef sid, RefVal V,
SmallVectorImpl<SymbolRef> &Leaked) const;
ProgramStateRef
handleAutoreleaseCounts(ProgramStateRef state, ExplodedNode *Pred,
const ProgramPointTag *Tag, CheckerContext &Ctx,
SymbolRef Sym, RefVal V) const;
ExplodedNode *processLeaks(ProgramStateRef state,
SmallVectorImpl<SymbolRef> &Leaked,
CheckerContext &Ctx,
ExplodedNode *Pred = nullptr) const;
};
} // end anonymous namespace
namespace {
class StopTrackingCallback final : public SymbolVisitor {
ProgramStateRef state;
public:
StopTrackingCallback(ProgramStateRef st) : state(std::move(st)) {}
ProgramStateRef getState() const { return state; }
bool VisitSymbol(SymbolRef sym) override {
state = state->remove<RefBindings>(sym);
return true;
}
};
} // end anonymous namespace
//===----------------------------------------------------------------------===//
// Handle statements that may have an effect on refcounts.
//===----------------------------------------------------------------------===//
void RetainCountChecker::checkPostStmt(const BlockExpr *BE,
CheckerContext &C) const {
// Scan the BlockDecRefExprs for any object the retain count checker
// may be tracking.
if (!BE->getBlockDecl()->hasCaptures())
return;
ProgramStateRef state = C.getState();
const BlockDataRegion *R =
cast<BlockDataRegion>(state->getSVal(BE,
C.getLocationContext()).getAsRegion());
BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(),
E = R->referenced_vars_end();
if (I == E)
return;
// FIXME: For now we invalidate the tracking of all symbols passed to blocks
// via captured variables, even though captured variables result in a copy
// and in implicit increment/decrement of a retain count.
SmallVector<const MemRegion*, 10> Regions;
const LocationContext *LC = C.getLocationContext();
MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager();
for ( ; I != E; ++I) {
const VarRegion *VR = I.getCapturedRegion();
if (VR->getSuperRegion() == R) {
VR = MemMgr.getVarRegion(VR->getDecl(), LC);
}
Regions.push_back(VR);
}
state =
state->scanReachableSymbols<StopTrackingCallback>(Regions.data(),
Regions.data() + Regions.size()).getState();
C.addTransition(state);
}
void RetainCountChecker::checkPostStmt(const CastExpr *CE,
CheckerContext &C) const {
const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE);
if (!BE)
return;
ArgEffect AE = IncRef;
switch (BE->getBridgeKind()) {
case clang::OBC_Bridge:
// Do nothing.
return;
case clang::OBC_BridgeRetained:
AE = IncRef;
break;
case clang::OBC_BridgeTransfer:
AE = DecRefBridgedTransferred;
break;
}
ProgramStateRef state = C.getState();
SymbolRef Sym = state->getSVal(CE, C.getLocationContext()).getAsLocSymbol();
if (!Sym)
return;
const RefVal* T = getRefBinding(state, Sym);
if (!T)
return;
RefVal::Kind hasErr = (RefVal::Kind) 0;
state = updateSymbol(state, Sym, *T, AE, hasErr, C);
if (hasErr) {
// FIXME: If we get an error during a bridge cast, should we report it?
return;
}
C.addTransition(state);
}
void RetainCountChecker::processObjCLiterals(CheckerContext &C,
const Expr *Ex) const {
ProgramStateRef state = C.getState();
const ExplodedNode *pred = C.getPredecessor();
for (const Stmt *Child : Ex->children()) {
SVal V = state->getSVal(Child, pred->getLocationContext());
if (SymbolRef sym = V.getAsSymbol())
if (const RefVal* T = getRefBinding(state, sym)) {
RefVal::Kind hasErr = (RefVal::Kind) 0;
state = updateSymbol(state, sym, *T, MayEscape, hasErr, C);
if (hasErr) {
processNonLeakError(state, Child->getSourceRange(), hasErr, sym, C);
return;
}
}
}
// Return the object as autoreleased.
// RetEffect RE = RetEffect::MakeNotOwned(RetEffect::ObjC);
if (SymbolRef sym =
state->getSVal(Ex, pred->getLocationContext()).getAsSymbol()) {
QualType ResultTy = Ex->getType();
state = setRefBinding(state, sym,
RefVal::makeNotOwned(RetEffect::ObjC, ResultTy));
}
C.addTransition(state);
}
void RetainCountChecker::checkPostStmt(const ObjCArrayLiteral *AL,
CheckerContext &C) const {
// Apply the 'MayEscape' to all values.
processObjCLiterals(C, AL);
}
void RetainCountChecker::checkPostStmt(const ObjCDictionaryLiteral *DL,
CheckerContext &C) const {
// Apply the 'MayEscape' to all keys and values.
processObjCLiterals(C, DL);
}
void RetainCountChecker::checkPostStmt(const ObjCBoxedExpr *Ex,
CheckerContext &C) const {
const ExplodedNode *Pred = C.getPredecessor();
const LocationContext *LCtx = Pred->getLocationContext();
ProgramStateRef State = Pred->getState();
if (SymbolRef Sym = State->getSVal(Ex, LCtx).getAsSymbol()) {
QualType ResultTy = Ex->getType();
State = setRefBinding(State, Sym,
RefVal::makeNotOwned(RetEffect::ObjC, ResultTy));
}
C.addTransition(State);
}
void RetainCountChecker::checkPostStmt(const ObjCIvarRefExpr *IRE,
CheckerContext &C) const {
Optional<Loc> IVarLoc = C.getSVal(IRE).getAs<Loc>();
if (!IVarLoc)
return;
ProgramStateRef State = C.getState();
SymbolRef Sym = State->getSVal(*IVarLoc).getAsSymbol();
if (!Sym || !dyn_cast_or_null<ObjCIvarRegion>(Sym->getOriginRegion()))
return;
// Accessing an ivar directly is unusual. If we've done that, be more
// forgiving about what the surrounding code is allowed to do.
QualType Ty = Sym->getType();
RetEffect::ObjKind Kind;
if (Ty->isObjCRetainableType())
Kind = RetEffect::ObjC;
else if (coreFoundation::isCFObjectRef(Ty))
Kind = RetEffect::CF;
else
return;
// If the value is already known to be nil, don't bother tracking it.
ConstraintManager &CMgr = State->getConstraintManager();
if (CMgr.isNull(State, Sym).isConstrainedTrue())
return;
if (const RefVal *RV = getRefBinding(State, Sym)) {
// If we've seen this symbol before, or we're only seeing it now because
// of something the analyzer has synthesized, don't do anything.
if (RV->getIvarAccessHistory() != RefVal::IvarAccessHistory::None ||
isSynthesizedAccessor(C.getStackFrame())) {
return;
}
// Note that this value has been loaded from an ivar.
C.addTransition(setRefBinding(State, Sym, RV->withIvarAccess()));
return;
}
RefVal PlusZero = RefVal::makeNotOwned(Kind, Ty);
// In a synthesized accessor, the effective retain count is +0.
if (isSynthesizedAccessor(C.getStackFrame())) {
C.addTransition(setRefBinding(State, Sym, PlusZero));
return;
}
State = setRefBinding(State, Sym, PlusZero.withIvarAccess());
C.addTransition(State);
}
void RetainCountChecker::checkPostCall(const CallEvent &Call,
CheckerContext &C) const {
RetainSummaryManager &Summaries = getSummaryManager(C);
const RetainSummary *Summ = Summaries.getSummary(Call, C.getState());
if (C.wasInlined) {
processSummaryOfInlined(*Summ, Call, C);
return;
}
checkSummary(*Summ, Call, C);
}
/// GetReturnType - Used to get the return type of a message expression or
/// function call with the intention of affixing that type to a tracked symbol.
/// While the return type can be queried directly from RetEx, when
/// invoking class methods we augment to the return type to be that of
/// a pointer to the class (as opposed it just being id).
// FIXME: We may be able to do this with related result types instead.
// This function is probably overestimating.
static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) {
QualType RetTy = RetE->getType();
// If RetE is not a message expression just return its type.
// If RetE is a message expression, return its types if it is something
/// more specific than id.
if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE))
if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>())
if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() ||
PT->isObjCClassType()) {
// At this point we know the return type of the message expression is
// id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this
// is a call to a class method whose type we can resolve. In such
// cases, promote the return type to XXX* (where XXX is the class).
const ObjCInterfaceDecl *D = ME->getReceiverInterface();
return !D ? RetTy :
Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D));
}
return RetTy;
}
// We don't always get the exact modeling of the function with regards to the
// retain count checker even when the function is inlined. For example, we need
// to stop tracking the symbols which were marked with StopTrackingHard.
void RetainCountChecker::processSummaryOfInlined(const RetainSummary &Summ,
const CallEvent &CallOrMsg,
CheckerContext &C) const {
ProgramStateRef state = C.getState();
// Evaluate the effect of the arguments.
for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) {
if (Summ.getArg(idx) == StopTrackingHard) {
SVal V = CallOrMsg.getArgSVal(idx);
if (SymbolRef Sym = V.getAsLocSymbol()) {
state = removeRefBinding(state, Sym);
}
}
}
// Evaluate the effect on the message receiver.
const ObjCMethodCall *MsgInvocation = dyn_cast<ObjCMethodCall>(&CallOrMsg);
if (MsgInvocation) {
if (SymbolRef Sym = MsgInvocation->getReceiverSVal().getAsLocSymbol()) {
if (Summ.getReceiverEffect() == StopTrackingHard) {
state = removeRefBinding(state, Sym);
}
}
}
// Consult the summary for the return value.
RetEffect RE = Summ.getRetEffect();
if (RE.getKind() == RetEffect::NoRetHard) {
SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol();
if (Sym)
state = removeRefBinding(state, Sym);
}
C.addTransition(state);
}
static ProgramStateRef updateOutParameter(ProgramStateRef State,
SVal ArgVal,
ArgEffect Effect) {
auto *ArgRegion = dyn_cast_or_null<TypedValueRegion>(ArgVal.getAsRegion());
if (!ArgRegion)
return State;
QualType PointeeTy = ArgRegion->getValueType();
if (!coreFoundation::isCFObjectRef(PointeeTy))
return State;
SVal PointeeVal = State->getSVal(ArgRegion);
SymbolRef Pointee = PointeeVal.getAsLocSymbol();
if (!Pointee)
return State;
switch (Effect) {
case UnretainedOutParameter:
State = setRefBinding(State, Pointee,
RefVal::makeNotOwned(RetEffect::CF, PointeeTy));
break;
case RetainedOutParameter:
// Do nothing. Retained out parameters will either point to a +1 reference
// or NULL, but the way you check for failure differs depending on the API.
// Consequently, we don't have a good way to track them yet.
break;
default:
llvm_unreachable("only for out parameters");
}
return State;
}
void RetainCountChecker::checkSummary(const RetainSummary &Summ,
const CallEvent &CallOrMsg,
CheckerContext &C) const {
ProgramStateRef state = C.getState();
// Evaluate the effect of the arguments.
RefVal::Kind hasErr = (RefVal::Kind) 0;
SourceRange ErrorRange;
SymbolRef ErrorSym = nullptr;
for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) {
SVal V = CallOrMsg.getArgSVal(idx);
ArgEffect Effect = Summ.getArg(idx);
if (Effect == RetainedOutParameter || Effect == UnretainedOutParameter) {
state = updateOutParameter(state, V, Effect);
} else if (SymbolRef Sym = V.getAsLocSymbol()) {
if (const RefVal *T = getRefBinding(state, Sym)) {
state = updateSymbol(state, Sym, *T, Effect, hasErr, C);
if (hasErr) {
ErrorRange = CallOrMsg.getArgSourceRange(idx);
ErrorSym = Sym;
break;
}
}
}
}
// Evaluate the effect on the message receiver.
bool ReceiverIsTracked = false;
if (!hasErr) {
const ObjCMethodCall *MsgInvocation = dyn_cast<ObjCMethodCall>(&CallOrMsg);
if (MsgInvocation) {
if (SymbolRef Sym = MsgInvocation->getReceiverSVal().getAsLocSymbol()) {
if (const RefVal *T = getRefBinding(state, Sym)) {
ReceiverIsTracked = true;
state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(),
hasErr, C);
if (hasErr) {
ErrorRange = MsgInvocation->getOriginExpr()->getReceiverRange();
ErrorSym = Sym;
}
}
}
}
}
// Process any errors.
if (hasErr) {
processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C);
return;
}
// Consult the summary for the return value.
RetEffect RE = Summ.getRetEffect();
if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) {
if (ReceiverIsTracked)
RE = getSummaryManager(C).getObjAllocRetEffect();
else
RE = RetEffect::MakeNoRet();
}
switch (RE.getKind()) {
default:
llvm_unreachable("Unhandled RetEffect.");
case RetEffect::NoRet:
case RetEffect::NoRetHard:
// No work necessary.
break;
case RetEffect::OwnedAllocatedSymbol:
case RetEffect::OwnedSymbol: {
SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol();
if (!Sym)
break;
// Use the result type from the CallEvent as it automatically adjusts
// for methods/functions that return references.
QualType ResultTy = CallOrMsg.getResultType();
state = setRefBinding(state, Sym, RefVal::makeOwned(RE.getObjKind(),
ResultTy));
// FIXME: Add a flag to the checker where allocations are assumed to
// *not* fail.
break;
}
case RetEffect::GCNotOwnedSymbol:
case RetEffect::NotOwnedSymbol: {
const Expr *Ex = CallOrMsg.getOriginExpr();
SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol();
if (!Sym)
break;
assert(Ex);
// Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *.
QualType ResultTy = GetReturnType(Ex, C.getASTContext());
state = setRefBinding(state, Sym, RefVal::makeNotOwned(RE.getObjKind(),
ResultTy));
break;
}
}
// This check is actually necessary; otherwise the statement builder thinks
// we've hit a previously-found path.
// Normally addTransition takes care of this, but we want the node pointer.
ExplodedNode *NewNode;
if (state == C.getState()) {
NewNode = C.getPredecessor();
} else {
NewNode = C.addTransition(state);
}
// Annotate the node with summary we used.
if (NewNode) {
// FIXME: This is ugly. See checkEndAnalysis for why it's necessary.
if (ShouldResetSummaryLog) {
SummaryLog.clear();
ShouldResetSummaryLog = false;
}
SummaryLog[NewNode] = &Summ;
}
}
ProgramStateRef
RetainCountChecker::updateSymbol(ProgramStateRef state, SymbolRef sym,
RefVal V, ArgEffect E, RefVal::Kind &hasErr,
CheckerContext &C) const {
// In GC mode [... release] and [... retain] do nothing.
// In ARC mode they shouldn't exist at all, but we just ignore them.
bool IgnoreRetainMsg = C.isObjCGCEnabled();
if (!IgnoreRetainMsg)
IgnoreRetainMsg = (bool)C.getASTContext().getLangOpts().ObjCAutoRefCount;
switch (E) {
default:
break;
case IncRefMsg:
E = IgnoreRetainMsg ? DoNothing : IncRef;
break;
case DecRefMsg:
E = IgnoreRetainMsg ? DoNothing : DecRef;
break;
case DecRefMsgAndStopTrackingHard:
E = IgnoreRetainMsg ? StopTracking : DecRefAndStopTrackingHard;
break;
case MakeCollectable:
E = C.isObjCGCEnabled() ? DecRef : DoNothing;
break;
}
// Handle all use-after-releases.
if (!C.isObjCGCEnabled() && V.getKind() == RefVal::Released) {
V = V ^ RefVal::ErrorUseAfterRelease;
hasErr = V.getKind();
return setRefBinding(state, sym, V);
}
switch (E) {
case DecRefMsg:
case IncRefMsg:
case MakeCollectable:
case DecRefMsgAndStopTrackingHard:
llvm_unreachable("DecRefMsg/IncRefMsg/MakeCollectable already converted");
case UnretainedOutParameter:
case RetainedOutParameter:
llvm_unreachable("Applies to pointer-to-pointer parameters, which should "
"not have ref state.");
case Dealloc:
// Any use of -dealloc in GC is *bad*.
if (C.isObjCGCEnabled()) {
V = V ^ RefVal::ErrorDeallocGC;
hasErr = V.getKind();
break;
}
switch (V.getKind()) {
default:
llvm_unreachable("Invalid RefVal state for an explicit dealloc.");
case RefVal::Owned:
// The object immediately transitions to the released state.
V = V ^ RefVal::Released;
V.clearCounts();
return setRefBinding(state, sym, V);
case RefVal::NotOwned:
V = V ^ RefVal::ErrorDeallocNotOwned;
hasErr = V.getKind();
break;
}
break;
case MayEscape:
if (V.getKind() == RefVal::Owned) {
V = V ^ RefVal::NotOwned;
break;
}
// Fall-through.
case DoNothing:
return state;
case Autorelease:
if (C.isObjCGCEnabled())
return state;
// Update the autorelease counts.
V = V.autorelease();
break;
case StopTracking:
case StopTrackingHard:
return removeRefBinding(state, sym);
case IncRef:
switch (V.getKind()) {
default:
llvm_unreachable("Invalid RefVal state for a retain.");
case RefVal::Owned:
case RefVal::NotOwned:
V = V + 1;
break;
case RefVal::Released:
// Non-GC cases are handled above.
assert(C.isObjCGCEnabled());
V = (V ^ RefVal::Owned) + 1;
break;
}
break;
case DecRef:
case DecRefBridgedTransferred:
case DecRefAndStopTrackingHard:
switch (V.getKind()) {
default:
// case 'RefVal::Released' handled above.
llvm_unreachable("Invalid RefVal state for a release.");
case RefVal::Owned:
assert(V.getCount() > 0);
if (V.getCount() == 1) {
if (E == DecRefBridgedTransferred ||
V.getIvarAccessHistory() ==
RefVal::IvarAccessHistory::AccessedDirectly)
V = V ^ RefVal::NotOwned;
else
V = V ^ RefVal::Released;
} else if (E == DecRefAndStopTrackingHard) {
return removeRefBinding(state, sym);
}
V = V - 1;
break;
case RefVal::NotOwned:
if (V.getCount() > 0) {
if (E == DecRefAndStopTrackingHard)
return removeRefBinding(state, sym);
V = V - 1;
} else if (V.getIvarAccessHistory() ==
RefVal::IvarAccessHistory::AccessedDirectly) {
// Assume that the instance variable was holding on the object at
// +1, and we just didn't know.
if (E == DecRefAndStopTrackingHard)
return removeRefBinding(state, sym);
V = V.releaseViaIvar() ^ RefVal::Released;
} else {
V = V ^ RefVal::ErrorReleaseNotOwned;
hasErr = V.getKind();
}
break;
case RefVal::Released:
// Non-GC cases are handled above.
assert(C.isObjCGCEnabled());
V = V ^ RefVal::ErrorUseAfterRelease;
hasErr = V.getKind();
break;
}
break;
}
return setRefBinding(state, sym, V);
}
void RetainCountChecker::processNonLeakError(ProgramStateRef St,
SourceRange ErrorRange,
RefVal::Kind ErrorKind,
SymbolRef Sym,
CheckerContext &C) const {
// HACK: Ignore retain-count issues on values accessed through ivars,
// because of cases like this:
// [_contentView retain];
// [_contentView removeFromSuperview];
// [self addSubview:_contentView]; // invalidates 'self'
// [_contentView release];
if (const RefVal *RV = getRefBinding(St, Sym))
if (RV->getIvarAccessHistory() != RefVal::IvarAccessHistory::None)
return;
ExplodedNode *N = C.generateErrorNode(St);
if (!N)
return;
CFRefBug *BT;
switch (ErrorKind) {
default:
llvm_unreachable("Unhandled error.");
case RefVal::ErrorUseAfterRelease:
if (!useAfterRelease)
useAfterRelease.reset(new UseAfterRelease(this));
BT = useAfterRelease.get();
break;
case RefVal::ErrorReleaseNotOwned:
if (!releaseNotOwned)
releaseNotOwned.reset(new BadRelease(this));
BT = releaseNotOwned.get();
break;
case RefVal::ErrorDeallocGC:
if (!deallocGC)
deallocGC.reset(new DeallocGC(this));
BT = deallocGC.get();
break;
case RefVal::ErrorDeallocNotOwned:
if (!deallocNotOwned)
deallocNotOwned.reset(new DeallocNotOwned(this));
BT = deallocNotOwned.get();
break;
}
assert(BT);
auto report = std::unique_ptr<BugReport>(
new CFRefReport(*BT, C.getASTContext().getLangOpts(), C.isObjCGCEnabled(),
SummaryLog, N, Sym));
report->addRange(ErrorRange);
C.emitReport(std::move(report));
}
//===----------------------------------------------------------------------===//
// Handle the return values of retain-count-related functions.
//===----------------------------------------------------------------------===//
bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const {
// Get the callee. We're only interested in simple C functions.
ProgramStateRef state = C.getState();
const FunctionDecl *FD = C.getCalleeDecl(CE);
if (!FD)
return false;
IdentifierInfo *II = FD->getIdentifier();
if (!II)
return false;
// For now, we're only handling the functions that return aliases of their
// arguments: CFRetain and CFMakeCollectable (and their families).
// Eventually we should add other functions we can model entirely,
// such as CFRelease, which don't invalidate their arguments or globals.
if (CE->getNumArgs() != 1)
return false;
// Get the name of the function.
StringRef FName = II->getName();
FName = FName.substr(FName.find_first_not_of('_'));
// See if it's one of the specific functions we know how to eval.
bool canEval = false;
QualType ResultTy = CE->getCallReturnType(C.getASTContext());
if (ResultTy->isObjCIdType()) {
// Handle: id NSMakeCollectable(CFTypeRef)
canEval = II->isStr("NSMakeCollectable");
} else if (ResultTy->isPointerType()) {
// Handle: (CF|CG)Retain
// CFAutorelease
// CFMakeCollectable
// It's okay to be a little sloppy here (CGMakeCollectable doesn't exist).
if (cocoa::isRefType(ResultTy, "CF", FName) ||
cocoa::isRefType(ResultTy, "CG", FName)) {
canEval = isRetain(FD, FName) || isAutorelease(FD, FName) ||
isMakeCollectable(FD, FName);
}
}
if (!canEval)
return false;
// Bind the return value.
const LocationContext *LCtx = C.getLocationContext();
SVal RetVal = state->getSVal(CE->getArg(0), LCtx);
if (RetVal.isUnknown()) {
// If the receiver is unknown, conjure a return value.
SValBuilder &SVB = C.getSValBuilder();
RetVal = SVB.conjureSymbolVal(nullptr, CE, LCtx, ResultTy, C.blockCount());
}
state = state->BindExpr(CE, LCtx, RetVal, false);
// FIXME: This should not be necessary, but otherwise the argument seems to be
// considered alive during the next statement.
if (const MemRegion *ArgRegion = RetVal.getAsRegion()) {
// Save the refcount status of the argument.
SymbolRef Sym = RetVal.getAsLocSymbol();
const RefVal *Binding = nullptr;
if (Sym)
Binding = getRefBinding(state, Sym);
// Invalidate the argument region.
state = state->invalidateRegions(ArgRegion, CE, C.blockCount(), LCtx,
/*CausesPointerEscape*/ false);
// Restore the refcount status of the argument.
if (Binding)
state = setRefBinding(state, Sym, *Binding);
}
C.addTransition(state);
return true;
}
//===----------------------------------------------------------------------===//
// Handle return statements.
//===----------------------------------------------------------------------===//
void RetainCountChecker::checkPreStmt(const ReturnStmt *S,
CheckerContext &C) const {
// Only adjust the reference count if this is the top-level call frame,
// and not the result of inlining. In the future, we should do
// better checking even for inlined calls, and see if they match
// with their expected semantics (e.g., the method should return a retained
// object, etc.).
if (!C.inTopFrame())
return;
const Expr *RetE = S->getRetValue();
if (!RetE)
return;
ProgramStateRef state = C.getState();
SymbolRef Sym =
state->getSValAsScalarOrLoc(RetE, C.getLocationContext()).getAsLocSymbol();
if (!Sym)
return;
// Get the reference count binding (if any).
const RefVal *T = getRefBinding(state, Sym);
if (!T)
return;
// Change the reference count.
RefVal X = *T;
switch (X.getKind()) {
case RefVal::Owned: {
unsigned cnt = X.getCount();
assert(cnt > 0);
X.setCount(cnt - 1);
X = X ^ RefVal::ReturnedOwned;
break;
}
case RefVal::NotOwned: {
unsigned cnt = X.getCount();
if (cnt) {
X.setCount(cnt - 1);
X = X ^ RefVal::ReturnedOwned;
}
else {
X = X ^ RefVal::ReturnedNotOwned;
}
break;
}
default:
return;
}
// Update the binding.
state = setRefBinding(state, Sym, X);
ExplodedNode *Pred = C.addTransition(state);
// At this point we have updated the state properly.
// Everything after this is merely checking to see if the return value has
// been over- or under-retained.
// Did we cache out?
if (!Pred)
return;
// Update the autorelease counts.
static CheckerProgramPointTag AutoreleaseTag(this, "Autorelease");
state = handleAutoreleaseCounts(state, Pred, &AutoreleaseTag, C, Sym, X);
// Did we cache out?
if (!state)
return;
// Get the updated binding.
T = getRefBinding(state, Sym);
assert(T);
X = *T;
// Consult the summary of the enclosing method.
RetainSummaryManager &Summaries = getSummaryManager(C);
const Decl *CD = &Pred->getCodeDecl();
RetEffect RE = RetEffect::MakeNoRet();
// FIXME: What is the convention for blocks? Is there one?
if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) {
const RetainSummary *Summ = Summaries.getMethodSummary(MD);
RE = Summ->getRetEffect();
} else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) {
if (!isa<CXXMethodDecl>(FD)) {
const RetainSummary *Summ = Summaries.getFunctionSummary(FD);
RE = Summ->getRetEffect();
}
}
checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state);
}
void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S,
CheckerContext &C,
ExplodedNode *Pred,
RetEffect RE, RefVal X,
SymbolRef Sym,
ProgramStateRef state) const {
// HACK: Ignore retain-count issues on values accessed through ivars,
// because of cases like this:
// [_contentView retain];
// [_contentView removeFromSuperview];
// [self addSubview:_contentView]; // invalidates 'self'
// [_contentView release];
if (X.getIvarAccessHistory() != RefVal::IvarAccessHistory::None)
return;
// Any leaks or other errors?
if (X.isReturnedOwned() && X.getCount() == 0) {
if (RE.getKind() != RetEffect::NoRet) {
bool hasError = false;
if (C.isObjCGCEnabled() && RE.getObjKind() == RetEffect::ObjC) {
// Things are more complicated with garbage collection. If the
// returned object is suppose to be an Objective-C object, we have
// a leak (as the caller expects a GC'ed object) because no
// method should return ownership unless it returns a CF object.
hasError = true;
X = X ^ RefVal::ErrorGCLeakReturned;
}
else if (!RE.isOwned()) {
// Either we are using GC and the returned object is a CF type
// or we aren't using GC. In either case, we expect that the
// enclosing method is expected to return ownership.
hasError = true;
X = X ^ RefVal::ErrorLeakReturned;
}
if (hasError) {
// Generate an error node.
state = setRefBinding(state, Sym, X);
static CheckerProgramPointTag ReturnOwnLeakTag(this, "ReturnsOwnLeak");
ExplodedNode *N = C.addTransition(state, Pred, &ReturnOwnLeakTag);
if (N) {
const LangOptions &LOpts = C.getASTContext().getLangOpts();
bool GCEnabled = C.isObjCGCEnabled();
C.emitReport(std::unique_ptr<BugReport>(new CFRefLeakReport(
*getLeakAtReturnBug(LOpts, GCEnabled), LOpts, GCEnabled,
SummaryLog, N, Sym, C, IncludeAllocationLine)));
}
}
}
} else if (X.isReturnedNotOwned()) {
if (RE.isOwned()) {
if (X.getIvarAccessHistory() ==
RefVal::IvarAccessHistory::AccessedDirectly) {
// Assume the method was trying to transfer a +1 reference from a
// strong ivar to the caller.
state = setRefBinding(state, Sym,
X.releaseViaIvar() ^ RefVal::ReturnedOwned);
} else {
// Trying to return a not owned object to a caller expecting an
// owned object.
state = setRefBinding(state, Sym, X ^ RefVal::ErrorReturnedNotOwned);
static CheckerProgramPointTag
ReturnNotOwnedTag(this, "ReturnNotOwnedForOwned");
ExplodedNode *N = C.addTransition(state, Pred, &ReturnNotOwnedTag);
if (N) {
if (!returnNotOwnedForOwned)
returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned(this));
C.emitReport(std::unique_ptr<BugReport>(new CFRefReport(
*returnNotOwnedForOwned, C.getASTContext().getLangOpts(),
C.isObjCGCEnabled(), SummaryLog, N, Sym)));
}
}
}
}
}
//===----------------------------------------------------------------------===//
// Check various ways a symbol can be invalidated.
//===----------------------------------------------------------------------===//
void RetainCountChecker::checkBind(SVal loc, SVal val, const Stmt *S,
CheckerContext &C) const {
// Are we storing to something that causes the value to "escape"?
bool escapes = true;
// A value escapes in three possible cases (this may change):
//
// (1) we are binding to something that is not a memory region.
// (2) we are binding to a memregion that does not have stack storage
// (3) we are binding to a memregion with stack storage that the store
// does not understand.
ProgramStateRef state = C.getState();
if (Optional<loc::MemRegionVal> regionLoc = loc.getAs<loc::MemRegionVal>()) {
escapes = !regionLoc->getRegion()->hasStackStorage();
if (!escapes) {
// To test (3), generate a new state with the binding added. If it is
// the same state, then it escapes (since the store cannot represent
// the binding).
// Do this only if we know that the store is not supposed to generate the
// same state.
SVal StoredVal = state->getSVal(regionLoc->getRegion());
if (StoredVal != val)
escapes = (state == (state->bindLoc(*regionLoc, val)));
}
if (!escapes) {
// Case 4: We do not currently model what happens when a symbol is
// assigned to a struct field, so be conservative here and let the symbol
// go. TODO: This could definitely be improved upon.
escapes = !isa<VarRegion>(regionLoc->getRegion());
}
}
// If we are storing the value into an auto function scope variable annotated
// with (__attribute__((cleanup))), stop tracking the value to avoid leak
// false positives.
if (const VarRegion *LVR = dyn_cast_or_null<VarRegion>(loc.getAsRegion())) {
const VarDecl *VD = LVR->getDecl();
if (VD->hasAttr<CleanupAttr>()) {
escapes = true;
}
}
// If our store can represent the binding and we aren't storing to something
// that doesn't have local storage then just return and have the simulation
// state continue as is.
if (!escapes)
return;
// Otherwise, find all symbols referenced by 'val' that we are tracking
// and stop tracking them.
state = state->scanReachableSymbols<StopTrackingCallback>(val).getState();
C.addTransition(state);
}
ProgramStateRef RetainCountChecker::evalAssume(ProgramStateRef state,
SVal Cond,
bool Assumption) const {
// FIXME: We may add to the interface of evalAssume the list of symbols
// whose assumptions have changed. For now we just iterate through the
// bindings and check if any of the tracked symbols are NULL. This isn't
// too bad since the number of symbols we will track in practice are
// probably small and evalAssume is only called at branches and a few
// other places.
RefBindingsTy B = state->get<RefBindings>();
if (B.isEmpty())
return state;
bool changed = false;
RefBindingsTy::Factory &RefBFactory = state->get_context<RefBindings>();
for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) {
// Check if the symbol is null stop tracking the symbol.
ConstraintManager &CMgr = state->getConstraintManager();
ConditionTruthVal AllocFailed = CMgr.isNull(state, I.getKey());
if (AllocFailed.isConstrainedTrue()) {
changed = true;
B = RefBFactory.remove(B, I.getKey());
}
}
if (changed)
state = state->set<RefBindings>(B);
return state;
}
ProgramStateRef
RetainCountChecker::checkRegionChanges(ProgramStateRef state,
const InvalidatedSymbols *invalidated,
ArrayRef<const MemRegion *> ExplicitRegions,
ArrayRef<const MemRegion *> Regions,
const CallEvent *Call) const {
if (!invalidated)
return state;
llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols;
for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(),
E = ExplicitRegions.end(); I != E; ++I) {
if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>())
WhitelistedSymbols.insert(SR->getSymbol());
}
for (InvalidatedSymbols::const_iterator I=invalidated->begin(),
E = invalidated->end(); I!=E; ++I) {
SymbolRef sym = *I;
if (WhitelistedSymbols.count(sym))
continue;
// Remove any existing reference-count binding.
state = removeRefBinding(state, sym);
}
return state;
}
//===----------------------------------------------------------------------===//
// Handle dead symbols and end-of-path.
//===----------------------------------------------------------------------===//
ProgramStateRef
RetainCountChecker::handleAutoreleaseCounts(ProgramStateRef state,
ExplodedNode *Pred,
const ProgramPointTag *Tag,
CheckerContext &Ctx,
SymbolRef Sym, RefVal V) const {
unsigned ACnt = V.getAutoreleaseCount();
// No autorelease counts? Nothing to be done.
if (!ACnt)
return state;
assert(!Ctx.isObjCGCEnabled() && "Autorelease counts in GC mode?");
unsigned Cnt = V.getCount();
// FIXME: Handle sending 'autorelease' to already released object.
if (V.getKind() == RefVal::ReturnedOwned)
++Cnt;
// If we would over-release here, but we know the value came from an ivar,
// assume it was a strong ivar that's just been relinquished.
if (ACnt > Cnt &&
V.getIvarAccessHistory() == RefVal::IvarAccessHistory::AccessedDirectly) {
V = V.releaseViaIvar();
--ACnt;
}
if (ACnt <= Cnt) {
if (ACnt == Cnt) {
V.clearCounts();
if (V.getKind() == RefVal::ReturnedOwned)
V = V ^ RefVal::ReturnedNotOwned;
else
V = V ^ RefVal::NotOwned;
} else {
V.setCount(V.getCount() - ACnt);
V.setAutoreleaseCount(0);
}
return setRefBinding(state, Sym, V);
}
// HACK: Ignore retain-count issues on values accessed through ivars,
// because of cases like this:
// [_contentView retain];
// [_contentView removeFromSuperview];
// [self addSubview:_contentView]; // invalidates 'self'
// [_contentView release];
if (V.getIvarAccessHistory() != RefVal::IvarAccessHistory::None)
return state;
// Woah! More autorelease counts then retain counts left.
// Emit hard error.
V = V ^ RefVal::ErrorOverAutorelease;
state = setRefBinding(state, Sym, V);
ExplodedNode *N = Ctx.generateSink(state, Pred, Tag);
if (N) {
SmallString<128> sbuf;
llvm::raw_svector_ostream os(sbuf);
os << "Object was autoreleased ";
if (V.getAutoreleaseCount() > 1)
os << V.getAutoreleaseCount() << " times but the object ";
else
os << "but ";
os << "has a +" << V.getCount() << " retain count";
if (!overAutorelease)
overAutorelease.reset(new OverAutorelease(this));
const LangOptions &LOpts = Ctx.getASTContext().getLangOpts();
Ctx.emitReport(std::unique_ptr<BugReport>(
new CFRefReport(*overAutorelease, LOpts, /* GCEnabled = */ false,
SummaryLog, N, Sym, os.str())));
}
return nullptr;
}
ProgramStateRef
RetainCountChecker::handleSymbolDeath(ProgramStateRef state,
SymbolRef sid, RefVal V,
SmallVectorImpl<SymbolRef> &Leaked) const {
bool hasLeak;
// HACK: Ignore retain-count issues on values accessed through ivars,
// because of cases like this:
// [_contentView retain];
// [_contentView removeFromSuperview];
// [self addSubview:_contentView]; // invalidates 'self'
// [_contentView release];
if (V.getIvarAccessHistory() != RefVal::IvarAccessHistory::None)
hasLeak = false;
else if (V.isOwned())
hasLeak = true;
else if (V.isNotOwned() || V.isReturnedOwned())
hasLeak = (V.getCount() > 0);
else
hasLeak = false;
if (!hasLeak)
return removeRefBinding(state, sid);
Leaked.push_back(sid);
return setRefBinding(state, sid, V ^ RefVal::ErrorLeak);
}
ExplodedNode *
RetainCountChecker::processLeaks(ProgramStateRef state,
SmallVectorImpl<SymbolRef> &Leaked,
CheckerContext &Ctx,
ExplodedNode *Pred) const {
// Generate an intermediate node representing the leak point.
ExplodedNode *N = Ctx.addTransition(state, Pred);
if (N) {
for (SmallVectorImpl<SymbolRef>::iterator
I = Leaked.begin(), E = Leaked.end(); I != E; ++I) {
const LangOptions &LOpts = Ctx.getASTContext().getLangOpts();
bool GCEnabled = Ctx.isObjCGCEnabled();
CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts, GCEnabled)
: getLeakAtReturnBug(LOpts, GCEnabled);
assert(BT && "BugType not initialized.");
Ctx.emitReport(std::unique_ptr<BugReport>(
new CFRefLeakReport(*BT, LOpts, GCEnabled, SummaryLog, N, *I, Ctx,
IncludeAllocationLine)));
}
}
return N;
}
void RetainCountChecker::checkEndFunction(CheckerContext &Ctx) const {
ProgramStateRef state = Ctx.getState();
RefBindingsTy B = state->get<RefBindings>();
ExplodedNode *Pred = Ctx.getPredecessor();
// Don't process anything within synthesized bodies.
const LocationContext *LCtx = Pred->getLocationContext();
if (LCtx->getAnalysisDeclContext()->isBodyAutosynthesized()) {
assert(LCtx->getParent());
return;
}
for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) {
state = handleAutoreleaseCounts(state, Pred, /*Tag=*/nullptr, Ctx,
I->first, I->second);
if (!state)
return;
}
// If the current LocationContext has a parent, don't check for leaks.
// We will do that later.
// FIXME: we should instead check for imbalances of the retain/releases,
// and suggest annotations.
if (LCtx->getParent())
return;
B = state->get<RefBindings>();
SmallVector<SymbolRef, 10> Leaked;
for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I)
state = handleSymbolDeath(state, I->first, I->second, Leaked);
processLeaks(state, Leaked, Ctx, Pred);
}
const ProgramPointTag *
RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const {
const CheckerProgramPointTag *&tag = DeadSymbolTags[sym];
if (!tag) {
SmallString<64> buf;
llvm::raw_svector_ostream out(buf);
out << "Dead Symbol : ";
sym->dumpToStream(out);
tag = new CheckerProgramPointTag(this, out.str());
}
return tag;
}
void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper,
CheckerContext &C) const {
ExplodedNode *Pred = C.getPredecessor();
ProgramStateRef state = C.getState();
RefBindingsTy B = state->get<RefBindings>();
SmallVector<SymbolRef, 10> Leaked;
// Update counts from autorelease pools
for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(),
E = SymReaper.dead_end(); I != E; ++I) {
SymbolRef Sym = *I;
if (const RefVal *T = B.lookup(Sym)){
// Use the symbol as the tag.
// FIXME: This might not be as unique as we would like.
const ProgramPointTag *Tag = getDeadSymbolTag(Sym);
state = handleAutoreleaseCounts(state, Pred, Tag, C, Sym, *T);
if (!state)
return;
// Fetch the new reference count from the state, and use it to handle
// this symbol.
state = handleSymbolDeath(state, *I, *getRefBinding(state, Sym), Leaked);
}
}
if (Leaked.empty()) {
C.addTransition(state);
return;
}
Pred = processLeaks(state, Leaked, C, Pred);
// Did we cache out?
if (!Pred)
return;
// Now generate a new node that nukes the old bindings.
// The only bindings left at this point are the leaked symbols.
RefBindingsTy::Factory &F = state->get_context<RefBindings>();
B = state->get<RefBindings>();
for (SmallVectorImpl<SymbolRef>::iterator I = Leaked.begin(),
E = Leaked.end();
I != E; ++I)
B = F.remove(B, *I);
state = state->set<RefBindings>(B);
C.addTransition(state, Pred);
}
void RetainCountChecker::printState(raw_ostream &Out, ProgramStateRef State,
const char *NL, const char *Sep) const {
RefBindingsTy B = State->get<RefBindings>();
if (B.isEmpty())
return;
Out << Sep << NL;
for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) {
Out << I->first << " : ";
I->second.print(Out);
Out << NL;
}
}
//===----------------------------------------------------------------------===//
// Checker registration.
//===----------------------------------------------------------------------===//
void ento::registerRetainCountChecker(CheckerManager &Mgr) {
Mgr.registerChecker<RetainCountChecker>(Mgr.getAnalyzerOptions());
}
//===----------------------------------------------------------------------===//
// Implementation of the CallEffects API.
//===----------------------------------------------------------------------===//
namespace clang {
namespace ento {
namespace objc_retain {
// This is a bit gross, but it allows us to populate CallEffects without
// creating a bunch of accessors. This kind is very localized, so the
// damage of this macro is limited.
#define createCallEffect(D, KIND)\
ASTContext &Ctx = D->getASTContext();\
LangOptions L = Ctx.getLangOpts();\
RetainSummaryManager M(Ctx, L.GCOnly, L.ObjCAutoRefCount);\
const RetainSummary *S = M.get ## KIND ## Summary(D);\
CallEffects CE(S->getRetEffect());\
CE.Receiver = S->getReceiverEffect();\
unsigned N = D->param_size();\
for (unsigned i = 0; i < N; ++i) {\
CE.Args.push_back(S->getArg(i));\
}
CallEffects CallEffects::getEffect(const ObjCMethodDecl *MD) {
createCallEffect(MD, Method);
return CE;
}
CallEffects CallEffects::getEffect(const FunctionDecl *FD) {
createCallEffect(FD, Function);
return CE;
}
#undef createCallEffect
} // end namespace objc_retain
} // end namespace ento
} // end namespace clang