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llvm-project/clang/lib/Checker/CFRefCount.cpp

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// CFRefCount.cpp - Transfer functions for tracking simple values -*- 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 CFRefCount, which implements
// a reference count checker for Core Foundation (Mac OS X).
//
//===----------------------------------------------------------------------===//
#include "clang/AST/DeclObjC.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Checker/BugReporter/BugType.h"
#include "clang/Checker/BugReporter/PathDiagnostic.h"
#include "clang/Checker/Checkers/LocalCheckers.h"
#include "clang/Checker/DomainSpecific/CocoaConventions.h"
#include "clang/Checker/PathSensitive/CheckerVisitor.h"
#include "clang/Checker/PathSensitive/GRExprEngineBuilders.h"
#include "clang/Checker/PathSensitive/GRStateTrait.h"
#include "clang/Checker/PathSensitive/GRTransferFuncs.h"
#include "clang/Checker/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/StringExtras.h"
#include <stdarg.h>
using namespace clang;
using llvm::StringRef;
using llvm::StrInStrNoCase;
namespace {
class InstanceReceiver {
const ObjCMessageExpr *ME;
const LocationContext *LC;
public:
InstanceReceiver(const ObjCMessageExpr *me = 0,
const LocationContext *lc = 0) : ME(me), LC(lc) {}
bool isValid() const {
return ME && ME->isInstanceMessage();
}
operator bool() const {
return isValid();
}
SVal getSValAsScalarOrLoc(const GRState *state) {
assert(isValid());
// We have an expression for the receiver? Fetch the value
// of that expression.
if (const Expr *Ex = ME->getInstanceReceiver())
return state->getSValAsScalarOrLoc(Ex);
// Otherwise we are sending a message to super. In this case the
// object reference is the same as 'self'.
if (const ImplicitParamDecl *SelfDecl = LC->getSelfDecl())
return state->getSVal(state->getRegion(SelfDecl, LC));
return UnknownVal();
}
SourceRange getSourceRange() const {
assert(isValid());
if (const Expr *Ex = ME->getInstanceReceiver())
return Ex->getSourceRange();
// Otherwise we are sending a message to super.
SourceLocation L = ME->getSuperLoc();
assert(L.isValid());
return SourceRange(L, L);
}
};
}
static const ObjCMethodDecl*
ResolveToInterfaceMethodDecl(const ObjCMethodDecl *MD) {
const ObjCInterfaceDecl *ID = MD->getClassInterface();
return MD->isInstanceMethod()
? ID->lookupInstanceMethod(MD->getSelector())
: ID->lookupClassMethod(MD->getSelector());
}
namespace {
class GenericNodeBuilder {
GRStmtNodeBuilder *SNB;
const Stmt *S;
const void *tag;
GREndPathNodeBuilder *ENB;
public:
GenericNodeBuilder(GRStmtNodeBuilder &snb, const Stmt *s,
const void *t)
: SNB(&snb), S(s), tag(t), ENB(0) {}
GenericNodeBuilder(GREndPathNodeBuilder &enb)
: SNB(0), S(0), tag(0), ENB(&enb) {}
ExplodedNode *MakeNode(const GRState *state, ExplodedNode *Pred) {
if (SNB)
return SNB->generateNode(PostStmt(S, Pred->getLocationContext(), tag),
state, Pred);
assert(ENB);
return ENB->generateNode(state, Pred);
}
};
} // end anonymous namespace
//===----------------------------------------------------------------------===//
// Primitives used for constructing summaries for function/method calls.
//===----------------------------------------------------------------------===//
/// ArgEffect is used to summarize a function/method call's effect on a
/// particular argument.
enum ArgEffect { Autorelease, Dealloc, DecRef, DecRefMsg, DoNothing,
DoNothingByRef, IncRefMsg, IncRef, MakeCollectable, MayEscape,
NewAutoreleasePool, SelfOwn, StopTracking };
namespace llvm {
template <> struct FoldingSetTrait<ArgEffect> {
static inline void Profile(const ArgEffect X, FoldingSetNodeID& ID) {
ID.AddInteger((unsigned) X);
}
};
} // end llvm namespace
/// ArgEffects summarizes the effects of a function/method call on all of
/// its arguments.
typedef llvm::ImmutableMap<unsigned,ArgEffect> ArgEffects;
namespace {
/// RetEffect is used to summarize a function/method call's behavior with
/// respect to its return value.
class RetEffect {
public:
enum Kind { NoRet, Alias, OwnedSymbol, OwnedAllocatedSymbol,
NotOwnedSymbol, GCNotOwnedSymbol, ReceiverAlias,
OwnedWhenTrackedReceiver };
enum ObjKind { CF, ObjC, AnyObj };
private:
Kind K;
ObjKind O;
unsigned index;
RetEffect(Kind k, unsigned idx = 0) : K(k), O(AnyObj), index(idx) {}
RetEffect(Kind k, ObjKind o) : K(k), O(o), index(0) {}
public:
Kind getKind() const { return K; }
ObjKind getObjKind() const { return O; }
unsigned getIndex() const {
assert(getKind() == Alias);
return index;
}
bool isOwned() const {
return K == OwnedSymbol || K == OwnedAllocatedSymbol ||
K == OwnedWhenTrackedReceiver;
}
static RetEffect MakeOwnedWhenTrackedReceiver() {
return RetEffect(OwnedWhenTrackedReceiver, ObjC);
}
static RetEffect MakeAlias(unsigned Idx) {
return RetEffect(Alias, Idx);
}
static RetEffect MakeReceiverAlias() {
return RetEffect(ReceiverAlias);
}
static RetEffect MakeOwned(ObjKind o, bool isAllocated = false) {
return RetEffect(isAllocated ? OwnedAllocatedSymbol : OwnedSymbol, o);
}
static RetEffect MakeNotOwned(ObjKind o) {
return RetEffect(NotOwnedSymbol, o);
}
static RetEffect MakeGCNotOwned() {
return RetEffect(GCNotOwnedSymbol, ObjC);
}
static RetEffect MakeNoRet() {
return RetEffect(NoRet);
}
};
//===----------------------------------------------------------------------===//
// Reference-counting logic (typestate + counts).
//===----------------------------------------------------------------------===//
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
};
private:
Kind kind;
RetEffect::ObjKind okind;
unsigned Cnt;
unsigned ACnt;
QualType T;
RefVal(Kind k, RetEffect::ObjKind o, unsigned cnt, unsigned acnt, QualType t)
: kind(k), okind(o), Cnt(cnt), ACnt(acnt), T(t) {}
public:
Kind getKind() const { return kind; }
RetEffect::ObjKind getObjKind() const { return okind; }
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; }
bool isOwned() const {
return getKind() == Owned;
}
bool isNotOwned() const {
return getKind() == NotOwned;
}
bool isReturnedOwned() const {
return getKind() == ReturnedOwned;
}
bool isReturnedNotOwned() const {
return getKind() == ReturnedNotOwned;
}
static RefVal makeOwned(RetEffect::ObjKind o, QualType t,
unsigned Count = 1) {
return RefVal(Owned, o, Count, 0, t);
}
static RefVal makeNotOwned(RetEffect::ObjKind o, QualType t,
unsigned Count = 0) {
return RefVal(NotOwned, o, Count, 0, t);
}
// Comparison, profiling, and pretty-printing.
bool operator==(const RefVal& X) const {
return kind == X.kind && Cnt == X.Cnt && T == X.T && ACnt == X.ACnt;
}
RefVal operator-(size_t i) const {
return RefVal(getKind(), getObjKind(), getCount() - i,
getAutoreleaseCount(), getType());
}
RefVal operator+(size_t i) const {
return RefVal(getKind(), getObjKind(), getCount() + i,
getAutoreleaseCount(), getType());
}
RefVal operator^(Kind k) const {
return RefVal(k, getObjKind(), getCount(), getAutoreleaseCount(),
getType());
}
RefVal autorelease() const {
return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount()+1,
getType());
}
void Profile(llvm::FoldingSetNodeID& ID) const {
ID.AddInteger((unsigned) kind);
ID.AddInteger(Cnt);
ID.AddInteger(ACnt);
ID.Add(T);
}
void print(llvm::raw_ostream& Out) const;
};
void RefVal::print(llvm::raw_ostream& Out) const {
if (!T.isNull())
Out << "Tracked Type:" << T.getAsString() << '\n';
switch (getKind()) {
default: assert(false);
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;
}
if (ACnt) {
Out << " [ARC +" << ACnt << ']';
}
}
} //end anonymous namespace
//===----------------------------------------------------------------------===//
// RefBindings - State used to track object reference counts.
//===----------------------------------------------------------------------===//
typedef llvm::ImmutableMap<SymbolRef, RefVal> RefBindings;
namespace clang {
template<>
struct GRStateTrait<RefBindings> : public GRStatePartialTrait<RefBindings> {
static void* GDMIndex() {
static int RefBIndex = 0;
return &RefBIndex;
}
};
}
//===----------------------------------------------------------------------===//
// Summaries
//===----------------------------------------------------------------------===//
namespace {
class RetainSummary {
/// Args - an ordered vector 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, returns an
/// alias of one of the arguments in the call, and so on.
RetEffect Ret;
/// EndPath - Indicates that execution of this method/function should
/// terminate the simulation of a path.
bool EndPath;
public:
RetainSummary(ArgEffects A, RetEffect R, ArgEffect defaultEff,
ArgEffect ReceiverEff, bool endpath = false)
: Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R),
EndPath(endpath) {}
/// 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;
}
/// 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; }
/// isEndPath - Returns true if executing the given method/function should
/// terminate the path.
bool isEndPath() const { return EndPath; }
/// 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; }
};
} // 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() : 0), S(s) {}
ObjCSummaryKey(const ObjCInterfaceDecl* d, IdentifierInfo *ii, Selector s)
: II(d ? d->getIdentifier() : ii), S(s) {}
ObjCSummaryKey(Selector s)
: II(0), S(s) {}
IdentifierInfo* getIdentifier() const { return II; }
Selector getSelector() const { return S; }
};
}
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) {
return (DenseMapInfo<IdentifierInfo*>::getHashValue(V.getIdentifier())
& 0x88888888)
| (DenseMapInfo<Selector>::getHashValue(V.getSelector())
& 0x55555555);
}
static bool isEqual(const ObjCSummaryKey& LHS, const ObjCSummaryKey& RHS) {
return DenseMapInfo<IdentifierInfo*>::isEqual(LHS.getIdentifier(),
RHS.getIdentifier()) &&
DenseMapInfo<Selector>::isEqual(LHS.getSelector(),
RHS.getSelector());
}
};
template <>
struct isPodLike<ObjCSummaryKey> { static const bool value = true; };
} // end llvm namespace
namespace {
class ObjCSummaryCache {
typedef llvm::DenseMap<ObjCSummaryKey, RetainSummary*> MapTy;
MapTy M;
public:
ObjCSummaryCache() {}
RetainSummary* find(const ObjCInterfaceDecl* D, IdentifierInfo *ClsName,
Selector S) {
// Lookup the method using the decl for the class @interface. If we
// have no decl, lookup using the class name.
return D ? find(D, S) : find(ClsName, S);
}
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() || !D)
return I->second;
// 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 NULL;
}
// Cache the summary with original key to make the next lookup faster
// and return the iterator.
RetainSummary *Summ = I->second;
M[K] = Summ;
return Summ;
}
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() ? NULL : I->second;
}
RetainSummary*& operator[](ObjCSummaryKey K) {
return M[K];
}
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*, RetainSummary*>
FuncSummariesTy;
typedef ObjCSummaryCache ObjCMethodSummariesTy;
//==-----------------------------------------------------------------==//
// Data.
//==-----------------------------------------------------------------==//
/// Ctx - The ASTContext object for the analyzed ASTs.
ASTContext& Ctx;
/// CFDictionaryCreateII - An IdentifierInfo* representing the indentifier
/// "CFDictionaryCreate".
IdentifierInfo* CFDictionaryCreateII;
/// GCEnabled - Records whether or not the analyzed code runs in GC mode.
const bool GCEnabled;
/// 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;
RetainSummary DefaultSummary;
RetainSummary* StopSummary;
//==-----------------------------------------------------------------==//
// Methods.
//==-----------------------------------------------------------------==//
/// getArgEffects - Returns a persistent ArgEffects object based on the
/// data in ScratchArgs.
ArgEffects getArgEffects();
enum UnaryFuncKind { cfretain, cfrelease, cfmakecollectable };
public:
RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; }
RetainSummary *getDefaultSummary() {
RetainSummary *Summ = (RetainSummary*) BPAlloc.Allocate<RetainSummary>();
return new (Summ) RetainSummary(DefaultSummary);
}
RetainSummary* getUnarySummary(const FunctionType* FT, UnaryFuncKind func);
RetainSummary* getCFSummaryCreateRule(const FunctionDecl* FD);
RetainSummary* getCFSummaryGetRule(const FunctionDecl* FD);
RetainSummary* getCFCreateGetRuleSummary(const FunctionDecl* FD,
StringRef FName);
RetainSummary* getPersistentSummary(ArgEffects AE, RetEffect RetEff,
ArgEffect ReceiverEff = DoNothing,
ArgEffect DefaultEff = MayEscape,
bool isEndPath = false);
RetainSummary* getPersistentSummary(RetEffect RE,
ArgEffect ReceiverEff = DoNothing,
ArgEffect DefaultEff = MayEscape) {
return getPersistentSummary(getArgEffects(), RE, ReceiverEff, DefaultEff);
}
RetainSummary *getPersistentStopSummary() {
if (StopSummary)
return StopSummary;
StopSummary = getPersistentSummary(RetEffect::MakeNoRet(),
StopTracking, StopTracking);
return StopSummary;
}
RetainSummary *getInitMethodSummary(QualType RetTy);
void InitializeClassMethodSummaries();
void InitializeMethodSummaries();
private:
void addNSObjectClsMethSummary(Selector S, RetainSummary *Summ) {
ObjCClassMethodSummaries[S] = Summ;
}
void addNSObjectMethSummary(Selector S, RetainSummary *Summ) {
ObjCMethodSummaries[S] = Summ;
}
void addClassMethSummary(const char* Cls, const char* nullaryName,
RetainSummary *Summ) {
IdentifierInfo* ClsII = &Ctx.Idents.get(Cls);
Selector S = GetNullarySelector(nullaryName, Ctx);
ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ;
}
void addInstMethSummary(const char* Cls, const char* nullaryName,
RetainSummary *Summ) {
IdentifierInfo* ClsII = &Ctx.Idents.get(Cls);
Selector S = GetNullarySelector(nullaryName, Ctx);
ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ;
}
Selector generateSelector(va_list argp) {
llvm::SmallVector<IdentifierInfo*, 10> II;
while (const char* s = va_arg(argp, const char*))
II.push_back(&Ctx.Idents.get(s));
return Ctx.Selectors.getSelector(II.size(), &II[0]);
}
void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy& Summaries,
RetainSummary* Summ, va_list argp) {
Selector S = generateSelector(argp);
Summaries[ObjCSummaryKey(ClsII, S)] = Summ;
}
void addInstMethSummary(const char* Cls, 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, RetainSummary* Summ, ...) {
va_list argp;
va_start(argp, Summ);
addMethodSummary(&Ctx.Idents.get(Cls),ObjCClassMethodSummaries, Summ, argp);
va_end(argp);
}
void addClsMethSummary(IdentifierInfo *II, RetainSummary* Summ, ...) {
va_list argp;
va_start(argp, Summ);
addMethodSummary(II, ObjCClassMethodSummaries, Summ, argp);
va_end(argp);
}
void addPanicSummary(const char* Cls, ...) {
RetainSummary* Summ = getPersistentSummary(AF.GetEmptyMap(),
RetEffect::MakeNoRet(),
DoNothing, DoNothing, true);
va_list argp;
va_start (argp, Cls);
addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, argp);
va_end(argp);
}
public:
RetainSummaryManager(ASTContext& ctx, bool gcenabled)
: Ctx(ctx),
CFDictionaryCreateII(&ctx.Idents.get("CFDictionaryCreate")),
GCEnabled(gcenabled), AF(BPAlloc), ScratchArgs(AF.GetEmptyMap()),
ObjCAllocRetE(gcenabled ? RetEffect::MakeGCNotOwned()
: RetEffect::MakeOwned(RetEffect::ObjC, true)),
ObjCInitRetE(gcenabled ? RetEffect::MakeGCNotOwned()
: RetEffect::MakeOwnedWhenTrackedReceiver()),
DefaultSummary(AF.GetEmptyMap() /* per-argument effects (none) */,
RetEffect::MakeNoRet() /* return effect */,
MayEscape, /* default argument effect */
DoNothing /* receiver effect */),
StopSummary(0) {
InitializeClassMethodSummaries();
InitializeMethodSummaries();
}
~RetainSummaryManager();
RetainSummary* getSummary(const FunctionDecl* FD);
RetainSummary *getInstanceMethodSummary(const ObjCMessageExpr *ME,
const GRState *state,
const LocationContext *LC);
RetainSummary* getInstanceMethodSummary(const ObjCMessageExpr* ME,
const ObjCInterfaceDecl* ID) {
return getInstanceMethodSummary(ME->getSelector(), 0,
ID, ME->getMethodDecl(), ME->getType());
}
RetainSummary* getInstanceMethodSummary(Selector S, IdentifierInfo *ClsName,
const ObjCInterfaceDecl* ID,
const ObjCMethodDecl *MD,
QualType RetTy);
RetainSummary *getClassMethodSummary(Selector S, IdentifierInfo *ClsName,
const ObjCInterfaceDecl *ID,
const ObjCMethodDecl *MD,
QualType RetTy);
RetainSummary *getClassMethodSummary(const ObjCMessageExpr *ME) {
ObjCInterfaceDecl *Class = 0;
switch (ME->getReceiverKind()) {
case ObjCMessageExpr::Class:
case ObjCMessageExpr::SuperClass:
Class = ME->getReceiverInterface();
break;
case ObjCMessageExpr::Instance:
case ObjCMessageExpr::SuperInstance:
break;
}
return getClassMethodSummary(ME->getSelector(),
Class? Class->getIdentifier() : 0,
Class,
ME->getMethodDecl(), ME->getType());
}
/// getMethodSummary - This version of getMethodSummary is used to query
/// the summary for the current method being analyzed.
RetainSummary *getMethodSummary(const ObjCMethodDecl *MD) {
// FIXME: Eventually this should be unneeded.
const ObjCInterfaceDecl *ID = MD->getClassInterface();
Selector S = MD->getSelector();
IdentifierInfo *ClsName = ID->getIdentifier();
QualType ResultTy = MD->getResultType();
// Resolve the method decl last.
if (const ObjCMethodDecl *InterfaceMD = ResolveToInterfaceMethodDecl(MD))
MD = InterfaceMD;
if (MD->isInstanceMethod())
return getInstanceMethodSummary(S, ClsName, ID, MD, ResultTy);
else
return getClassMethodSummary(S, ClsName, ID, MD, ResultTy);
}
RetainSummary* getCommonMethodSummary(const ObjCMethodDecl* MD,
Selector S, QualType RetTy);
void updateSummaryFromAnnotations(RetainSummary &Summ,
const ObjCMethodDecl *MD);
void updateSummaryFromAnnotations(RetainSummary &Summ,
const FunctionDecl *FD);
bool isGCEnabled() const { return GCEnabled; }
RetainSummary *copySummary(RetainSummary *OldSumm) {
RetainSummary *Summ = (RetainSummary*) BPAlloc.Allocate<RetainSummary>();
new (Summ) RetainSummary(*OldSumm);
return Summ;
}
};
} // end anonymous namespace
//===----------------------------------------------------------------------===//
// Implementation of checker data structures.
//===----------------------------------------------------------------------===//
RetainSummaryManager::~RetainSummaryManager() {}
ArgEffects RetainSummaryManager::getArgEffects() {
ArgEffects AE = ScratchArgs;
ScratchArgs = AF.GetEmptyMap();
return AE;
}
RetainSummary*
RetainSummaryManager::getPersistentSummary(ArgEffects AE, RetEffect RetEff,
ArgEffect ReceiverEff,
ArgEffect DefaultEff,
bool isEndPath) {
// Create the summary and return it.
RetainSummary *Summ = (RetainSummary*) BPAlloc.Allocate<RetainSummary>();
new (Summ) RetainSummary(AE, RetEff, DefaultEff, ReceiverEff, isEndPath);
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");
}
RetainSummary* RetainSummaryManager::getSummary(const FunctionDecl* FD) {
// 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.
RetainSummary *S = 0;
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->getResultType();
// FIXME: This should all be refactored into a chain of "summary lookup"
// filters.
assert(ScratchArgs.isEmpty());
if (FName == "pthread_create") {
// Part of: <rdar://problem/7299394>. This will be addressed
// better with IPA.
S = getPersistentStopSummary();
} else if (FName == "NSMakeCollectable") {
// Handle: id NSMakeCollectable(CFTypeRef)
S = (RetTy->isObjCIdType())
? getUnarySummary(FT, cfmakecollectable)
: getPersistentStopSummary();
} else if (FName == "IOBSDNameMatching" ||
FName == "IOServiceMatching" ||
FName == "IOServiceNameMatching" ||
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);
}
// Did we get a summary?
if (S)
break;
// Enable this code once the semantics of NSDeallocateObject are resolved
// for GC. <rdar://problem/6619988>
#if 0
// Handle: NSDeallocateObject(id anObject);
// This method does allow 'nil' (although we don't check it now).
if (strcmp(FName, "NSDeallocateObject") == 0) {
return RetTy == Ctx.VoidTy
? getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, Dealloc)
: getPersistentStopSummary();
}
#endif
if (RetTy->isPointerType()) {
// For CoreFoundation ('CF') types.
if (cocoa::isRefType(RetTy, "CF", FName)) {
if (isRetain(FD, FName))
S = getUnarySummary(FT, cfretain);
else if (FName.find("MakeCollectable") != StringRef::npos)
S = getUnarySummary(FT, cfmakecollectable);
else
S = getCFCreateGetRuleSummary(FD, FName);
break;
}
// For CoreGraphics ('CG') types.
if (cocoa::isRefType(RetTy, "CG", FName)) {
if (isRetain(FD, FName))
S = getUnarySummary(FT, cfretain);
else
S = getCFCreateGetRuleSummary(FD, FName);
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, FName);
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 (!S)
S = getDefaultSummary();
// Annotations override defaults.
assert(S);
updateSummaryFromAnnotations(*S, FD);
FuncSummaries[FD] = S;
return S;
}
RetainSummary*
RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl* FD,
StringRef FName) {
if (FName.find("Create") != StringRef::npos ||
FName.find("Copy") != StringRef::npos)
return getCFSummaryCreateRule(FD);
if (FName.find("Get") != StringRef::npos)
return getCFSummaryGetRule(FD);
return getDefaultSummary();
}
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->getNumArgs() != 1)
return getPersistentStopSummary();
assert (ScratchArgs.isEmpty());
switch (func) {
case cfretain: {
ScratchArgs = AF.Add(ScratchArgs, 0, IncRef);
return getPersistentSummary(RetEffect::MakeAlias(0),
DoNothing, DoNothing);
}
case cfrelease: {
ScratchArgs = AF.Add(ScratchArgs, 0, DecRef);
return getPersistentSummary(RetEffect::MakeNoRet(),
DoNothing, DoNothing);
}
case cfmakecollectable: {
ScratchArgs = AF.Add(ScratchArgs, 0, MakeCollectable);
return getPersistentSummary(RetEffect::MakeAlias(0),DoNothing, DoNothing);
}
default:
assert (false && "Not a supported unary function.");
return getDefaultSummary();
}
}
RetainSummary*
RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl* FD) {
assert (ScratchArgs.isEmpty());
if (FD->getIdentifier() == CFDictionaryCreateII) {
ScratchArgs = AF.Add(ScratchArgs, 1, DoNothingByRef);
ScratchArgs = AF.Add(ScratchArgs, 2, DoNothingByRef);
}
return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true));
}
RetainSummary*
RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl* FD) {
assert (ScratchArgs.isEmpty());
return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF),
DoNothing, DoNothing);
}
//===----------------------------------------------------------------------===//
// Summary creation for Selectors.
//===----------------------------------------------------------------------===//
RetainSummary*
RetainSummaryManager::getInitMethodSummary(QualType RetTy) {
assert(ScratchArgs.isEmpty());
// 'init' methods conceptually return a newly allocated object and claim
// the receiver.
if (cocoa::isCocoaObjectRef(RetTy) || cocoa::isCFObjectRef(RetTy))
return getPersistentSummary(ObjCInitRetE, DecRefMsg);
return getDefaultSummary();
}
void
RetainSummaryManager::updateSummaryFromAnnotations(RetainSummary &Summ,
const FunctionDecl *FD) {
if (!FD)
return;
QualType RetTy = FD->getResultType();
// Determine if there is a special return effect for this method.
if (cocoa::isCocoaObjectRef(RetTy)) {
if (FD->getAttr<NSReturnsRetainedAttr>()) {
Summ.setRetEffect(ObjCAllocRetE);
}
else if (FD->getAttr<CFReturnsRetainedAttr>()) {
Summ.setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true));
}
else if (FD->getAttr<NSReturnsNotRetainedAttr>()) {
Summ.setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC));
}
else if (FD->getAttr<CFReturnsNotRetainedAttr>()) {
Summ.setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF));
}
}
else if (RetTy->getAs<PointerType>()) {
if (FD->getAttr<CFReturnsRetainedAttr>()) {
Summ.setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true));
}
}
}
void
RetainSummaryManager::updateSummaryFromAnnotations(RetainSummary &Summ,
const ObjCMethodDecl *MD) {
if (!MD)
return;
bool isTrackedLoc = false;
// Determine if there is a special return effect for this method.
if (cocoa::isCocoaObjectRef(MD->getResultType())) {
if (MD->getAttr<NSReturnsRetainedAttr>()) {
Summ.setRetEffect(ObjCAllocRetE);
return;
}
if (MD->getAttr<NSReturnsNotRetainedAttr>()) {
Summ.setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC));
return;
}
isTrackedLoc = true;
}
if (!isTrackedLoc)
isTrackedLoc = MD->getResultType()->getAs<PointerType>() != NULL;
if (isTrackedLoc) {
if (MD->getAttr<CFReturnsRetainedAttr>())
Summ.setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true));
else if (MD->getAttr<CFReturnsNotRetainedAttr>())
Summ.setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF));
}
}
RetainSummary*
RetainSummaryManager::getCommonMethodSummary(const ObjCMethodDecl* MD,
Selector S, QualType RetTy) {
if (MD) {
// Scan the method decl for 'void*' arguments. These should be treated
// as 'StopTracking' because they are often used with delegates.
// Delegates are a frequent form of false positives with the retain
// count checker.
unsigned i = 0;
for (ObjCMethodDecl::param_iterator I = MD->param_begin(),
E = MD->param_end(); I != E; ++I, ++i)
if (ParmVarDecl *PD = *I) {
QualType Ty = Ctx.getCanonicalType(PD->getType());
if (Ty.getLocalUnqualifiedType() == Ctx.VoidPtrTy)
ScratchArgs = AF.Add(ScratchArgs, i, StopTracking);
}
}
// Any special effect for the receiver?
ArgEffect ReceiverEff = DoNothing;
// 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()) {
const std::string &str = S.getAsString();
assert(!str.empty());
if (StrInStrNoCase(str, "delegate:") != StringRef::npos)
ReceiverEff = StopTracking;
}
// Look for methods that return an owned object.
if (cocoa::isCocoaObjectRef(RetTy)) {
// EXPERIMENTAL: Assume the Cocoa conventions for all objects returned
// by instance methods.
RetEffect E = cocoa::followsFundamentalRule(S)
? ObjCAllocRetE : RetEffect::MakeNotOwned(RetEffect::ObjC);
return getPersistentSummary(E, ReceiverEff, MayEscape);
}
// Look for methods that return an owned core foundation object.
if (cocoa::isCFObjectRef(RetTy)) {
RetEffect E = cocoa::followsFundamentalRule(S)
? RetEffect::MakeOwned(RetEffect::CF, true)
: RetEffect::MakeNotOwned(RetEffect::CF);
return getPersistentSummary(E, ReceiverEff, MayEscape);
}
if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing)
return getDefaultSummary();
return getPersistentSummary(RetEffect::MakeNoRet(), ReceiverEff, MayEscape);
}
RetainSummary*
RetainSummaryManager::getInstanceMethodSummary(const ObjCMessageExpr *ME,
const GRState *state,
const LocationContext *LC) {
// We need the type-information of the tracked receiver object
// Retrieve it from the state.
const Expr *Receiver = ME->getInstanceReceiver();
const ObjCInterfaceDecl* ID = 0;
// FIXME: Is this really working as expected? There are cases where
// we just use the 'ID' from the message expression.
SVal receiverV;
if (Receiver) {
receiverV = state->getSValAsScalarOrLoc(Receiver);
// FIXME: Eventually replace the use of state->get<RefBindings> with
// a generic API for reasoning about the Objective-C types of symbolic
// objects.
if (SymbolRef Sym = receiverV.getAsLocSymbol())
if (const RefVal *T = state->get<RefBindings>(Sym))
if (const ObjCObjectPointerType* PT =
T->getType()->getAs<ObjCObjectPointerType>())
ID = PT->getInterfaceDecl();
// FIXME: this is a hack. This may or may not be the actual method
// that is called.
if (!ID) {
if (const ObjCObjectPointerType *PT =
Receiver->getType()->getAs<ObjCObjectPointerType>())
ID = PT->getInterfaceDecl();
}
} else {
// FIXME: Hack for 'super'.
ID = ME->getReceiverInterface();
}
// FIXME: The receiver could be a reference to a class, meaning that
// we should use the class method.
RetainSummary *Summ = getInstanceMethodSummary(ME, ID);
// Special-case: are we sending a mesage to "self"?
// This is a hack. When we have full-IP this should be removed.
if (isa<ObjCMethodDecl>(LC->getDecl()) && Receiver) {
if (const loc::MemRegionVal *L = dyn_cast<loc::MemRegionVal>(&receiverV)) {
// Get the region associated with 'self'.
if (const ImplicitParamDecl *SelfDecl = LC->getSelfDecl()) {
SVal SelfVal = state->getSVal(state->getRegion(SelfDecl, LC));
if (L->StripCasts() == SelfVal.getAsRegion()) {
// Update the summary to make the default argument effect
// 'StopTracking'.
Summ = copySummary(Summ);
Summ->setDefaultArgEffect(StopTracking);
}
}
}
}
return Summ ? Summ : getDefaultSummary();
}
RetainSummary*
RetainSummaryManager::getInstanceMethodSummary(Selector S,
IdentifierInfo *ClsName,
const ObjCInterfaceDecl* ID,
const ObjCMethodDecl *MD,
QualType RetTy) {
// Look up a summary in our summary cache.
RetainSummary *Summ = ObjCMethodSummaries.find(ID, ClsName, S);
if (!Summ) {
assert(ScratchArgs.isEmpty());
// "initXXX": pass-through for receiver.
if (cocoa::deriveNamingConvention(S) == cocoa::InitRule)
Summ = getInitMethodSummary(RetTy);
else
Summ = getCommonMethodSummary(MD, S, RetTy);
// Annotations override defaults.
updateSummaryFromAnnotations(*Summ, MD);
// Memoize the summary.
ObjCMethodSummaries[ObjCSummaryKey(ID, ClsName, S)] = Summ;
}
return Summ;
}
RetainSummary*
RetainSummaryManager::getClassMethodSummary(Selector S, IdentifierInfo *ClsName,
const ObjCInterfaceDecl *ID,
const ObjCMethodDecl *MD,
QualType RetTy) {
assert(ClsName && "Class name must be specified.");
RetainSummary *Summ = ObjCClassMethodSummaries.find(ID, ClsName, S);
if (!Summ) {
Summ = getCommonMethodSummary(MD, S, RetTy);
// Annotations override defaults.
updateSummaryFromAnnotations(*Summ, MD);
// Memoize the summary.
ObjCClassMethodSummaries[ObjCSummaryKey(ID, ClsName, S)] = Summ;
}
return Summ;
}
void RetainSummaryManager::InitializeClassMethodSummaries() {
assert(ScratchArgs.isEmpty());
RetainSummary* Summ = getPersistentSummary(ObjCAllocRetE);
// Create the summaries for "alloc", "new", and "allocWithZone:" for
// NSObject and its derivatives.
addNSObjectClsMethSummary(GetNullarySelector("alloc", Ctx), Summ);
addNSObjectClsMethSummary(GetNullarySelector("new", Ctx), Summ);
addNSObjectClsMethSummary(GetUnarySelector("allocWithZone", Ctx), Summ);
// 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));
// Create a summary for [NSCursor dragCopyCursor].
addClassMethSummary("NSCursor", "dragCopyCursor",
getPersistentSummary(RetEffect::MakeNoRet(), DoNothing,
DoNothing));
// Create the summaries for [NSObject performSelector...]. We treat
// these as 'stop tracking' for the arguments because they are often
// used for delegates that can release the object. When we have better
// inter-procedural analysis we can potentially do something better. This
// workaround is to remove false positives.
Summ = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, StopTracking);
IdentifierInfo *NSObjectII = &Ctx.Idents.get("NSObject");
addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject",
"afterDelay", NULL);
addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject",
"afterDelay", "inModes", NULL);
addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread",
"withObject", "waitUntilDone", NULL);
addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread",
"withObject", "waitUntilDone", "modes", NULL);
addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread",
"withObject", "waitUntilDone", NULL);
addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread",
"withObject", "waitUntilDone", "modes", NULL);
addClsMethSummary(NSObjectII, Summ, "performSelectorInBackground",
"withObject", NULL);
// Specially handle NSData.
RetainSummary *dataWithBytesNoCopySumm =
getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC), DoNothing,
DoNothing);
addClsMethSummary("NSData", dataWithBytesNoCopySumm,
"dataWithBytesNoCopy", "length", NULL);
addClsMethSummary("NSData", dataWithBytesNoCopySumm,
"dataWithBytesNoCopy", "length", "freeWhenDone", NULL);
}
void RetainSummaryManager::InitializeMethodSummaries() {
assert (ScratchArgs.isEmpty());
// Create the "init" selector. It just acts as a pass-through for the
// receiver.
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.
RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE);
RetainSummary *CFAllocSumm =
getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true));
// Create the "copy" selector.
addNSObjectMethSummary(GetNullarySelector("copy", Ctx), AllocSumm);
// Create the "mutableCopy" selector.
addNSObjectMethSummary(GetNullarySelector("mutableCopy", Ctx), AllocSumm);
// Create the "retain" selector.
RetEffect E = RetEffect::MakeReceiverAlias();
RetainSummary *Summ = getPersistentSummary(E, IncRefMsg);
addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ);
// Create the "release" selector.
Summ = getPersistentSummary(E, DecRefMsg);
addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ);
// Create the "drain" selector.
Summ = getPersistentSummary(E, isGCEnabled() ? DoNothing : DecRef);
addNSObjectMethSummary(GetNullarySelector("drain", Ctx), Summ);
// Create the -dealloc summary.
Summ = getPersistentSummary(RetEffect::MakeNoRet(), Dealloc);
addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ);
// Create the "autorelease" selector.
Summ = getPersistentSummary(E, Autorelease);
addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ);
// Specially handle NSAutoreleasePool.
addInstMethSummary("NSAutoreleasePool", "init",
getPersistentSummary(RetEffect::MakeReceiverAlias(),
NewAutoreleasePool));
// 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.
RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(),
StopTracking,
StopTracking);
addClassMethSummary("NSWindow", "alloc", NoTrackYet);
#if 0
addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect",
"styleMask", "backing", "defer", NULL);
addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect",
"styleMask", "backing", "defer", "screen", NULL);
#endif
// 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);
#if 0
addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect",
"styleMask", "backing", "defer", NULL);
addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect",
"styleMask", "backing", "defer", "screen", NULL);
#endif
// Don't track allocated autorelease pools yet, as it is okay to prematurely
// exit a method.
addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet);
// Create NSAssertionHandler summaries.
addPanicSummary("NSAssertionHandler", "handleFailureInFunction", "file",
"lineNumber", "description", NULL);
addPanicSummary("NSAssertionHandler", "handleFailureInMethod", "object",
"file", "lineNumber", "description", NULL);
// Create summaries QCRenderer/QCView -createSnapShotImageOfType:
addInstMethSummary("QCRenderer", AllocSumm,
"createSnapshotImageOfType", NULL);
addInstMethSummary("QCView", AllocSumm,
"createSnapshotImageOfType", NULL);
// Create summaries for CIContext, 'createCGImage' and
// 'createCGLayerWithSize'. These objects are CF objects, and are not
// automatically garbage collected.
addInstMethSummary("CIContext", CFAllocSumm,
"createCGImage", "fromRect", NULL);
addInstMethSummary("CIContext", CFAllocSumm,
"createCGImage", "fromRect", "format", "colorSpace", NULL);
addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize",
"info", NULL);
}
//===----------------------------------------------------------------------===//
// AutoreleaseBindings - State used to track objects in autorelease pools.
//===----------------------------------------------------------------------===//
typedef llvm::ImmutableMap<SymbolRef, unsigned> ARCounts;
typedef llvm::ImmutableMap<SymbolRef, ARCounts> ARPoolContents;
typedef llvm::ImmutableList<SymbolRef> ARStack;
static int AutoRCIndex = 0;
static int AutoRBIndex = 0;
namespace { class AutoreleasePoolContents {}; }
namespace { class AutoreleaseStack {}; }
namespace clang {
template<> struct GRStateTrait<AutoreleaseStack>
: public GRStatePartialTrait<ARStack> {
static inline void* GDMIndex() { return &AutoRBIndex; }
};
template<> struct GRStateTrait<AutoreleasePoolContents>
: public GRStatePartialTrait<ARPoolContents> {
static inline void* GDMIndex() { return &AutoRCIndex; }
};
} // end clang namespace
static SymbolRef GetCurrentAutoreleasePool(const GRState* state) {
ARStack stack = state->get<AutoreleaseStack>();
return stack.isEmpty() ? SymbolRef() : stack.getHead();
}
static const GRState * SendAutorelease(const GRState *state,
ARCounts::Factory &F, SymbolRef sym) {
SymbolRef pool = GetCurrentAutoreleasePool(state);
const ARCounts *cnts = state->get<AutoreleasePoolContents>(pool);
ARCounts newCnts(0);
if (cnts) {
const unsigned *cnt = (*cnts).lookup(sym);
newCnts = F.Add(*cnts, sym, cnt ? *cnt + 1 : 1);
}
else
newCnts = F.Add(F.GetEmptyMap(), sym, 1);
return state->set<AutoreleasePoolContents>(pool, newCnts);
}
//===----------------------------------------------------------------------===//
// Transfer functions.
//===----------------------------------------------------------------------===//
namespace {
class CFRefCount : public GRTransferFuncs {
public:
class BindingsPrinter : public GRState::Printer {
public:
virtual void Print(llvm::raw_ostream& Out, const GRState* state,
const char* nl, const char* sep);
};
private:
typedef llvm::DenseMap<const ExplodedNode*, const RetainSummary*>
SummaryLogTy;
RetainSummaryManager Summaries;
SummaryLogTy SummaryLog;
const LangOptions& LOpts;
ARCounts::Factory ARCountFactory;
BugType *useAfterRelease, *releaseNotOwned;
BugType *deallocGC, *deallocNotOwned;
BugType *leakWithinFunction, *leakAtReturn;
BugType *overAutorelease;
BugType *returnNotOwnedForOwned;
BugReporter *BR;
const GRState * Update(const GRState * state, SymbolRef sym, RefVal V, ArgEffect E,
RefVal::Kind& hasErr);
void ProcessNonLeakError(ExplodedNodeSet& Dst,
GRStmtNodeBuilder& Builder,
const Expr* NodeExpr, SourceRange ErrorRange,
ExplodedNode* Pred,
const GRState* St,
RefVal::Kind hasErr, SymbolRef Sym);
const GRState * HandleSymbolDeath(const GRState * state, SymbolRef sid, RefVal V,
llvm::SmallVectorImpl<SymbolRef> &Leaked);
ExplodedNode* ProcessLeaks(const GRState * state,
llvm::SmallVectorImpl<SymbolRef> &Leaked,
GenericNodeBuilder &Builder,
GRExprEngine &Eng,
ExplodedNode *Pred = 0);
public:
CFRefCount(ASTContext& Ctx, bool gcenabled, const LangOptions& lopts)
: Summaries(Ctx, gcenabled),
LOpts(lopts), useAfterRelease(0), releaseNotOwned(0),
deallocGC(0), deallocNotOwned(0),
leakWithinFunction(0), leakAtReturn(0), overAutorelease(0),
returnNotOwnedForOwned(0), BR(0) {}
virtual ~CFRefCount() {}
void RegisterChecks(GRExprEngine &Eng);
virtual void RegisterPrinters(std::vector<GRState::Printer*>& Printers) {
Printers.push_back(new BindingsPrinter());
}
bool isGCEnabled() const { return Summaries.isGCEnabled(); }
const LangOptions& getLangOptions() const { return LOpts; }
const RetainSummary *getSummaryOfNode(const ExplodedNode *N) const {
SummaryLogTy::const_iterator I = SummaryLog.find(N);
return I == SummaryLog.end() ? 0 : I->second;
}
// Calls.
void EvalSummary(ExplodedNodeSet& Dst,
GRExprEngine& Eng,
GRStmtNodeBuilder& Builder,
const Expr* Ex,
InstanceReceiver Receiver,
const RetainSummary& Summ,
const MemRegion *Callee,
ConstExprIterator arg_beg, ConstExprIterator arg_end,
ExplodedNode* Pred, const GRState *state);
virtual void EvalCall(ExplodedNodeSet& Dst,
GRExprEngine& Eng,
GRStmtNodeBuilder& Builder,
const CallExpr* CE, SVal L,
ExplodedNode* Pred);
virtual void EvalObjCMessageExpr(ExplodedNodeSet& Dst,
GRExprEngine& Engine,
GRStmtNodeBuilder& Builder,
const ObjCMessageExpr* ME,
ExplodedNode* Pred,
const GRState *state);
// Stores.
virtual void EvalBind(GRStmtNodeBuilderRef& B, SVal location, SVal val);
// End-of-path.
virtual void EvalEndPath(GRExprEngine& Engine,
GREndPathNodeBuilder& Builder);
virtual void EvalDeadSymbols(ExplodedNodeSet& Dst,
GRExprEngine& Engine,
GRStmtNodeBuilder& Builder,
ExplodedNode* Pred,
const GRState* state,
SymbolReaper& SymReaper);
std::pair<ExplodedNode*, const GRState *>
HandleAutoreleaseCounts(const GRState * state, GenericNodeBuilder Bd,
ExplodedNode* Pred, GRExprEngine &Eng,
SymbolRef Sym, RefVal V, bool &stop);
// Return statements.
virtual void EvalReturn(ExplodedNodeSet& Dst,
GRExprEngine& Engine,
GRStmtNodeBuilder& Builder,
const ReturnStmt* S,
ExplodedNode* Pred);
// Assumptions.
virtual const GRState *EvalAssume(const GRState* state, SVal condition,
bool assumption);
};
} // end anonymous namespace
static void PrintPool(llvm::raw_ostream &Out, SymbolRef Sym,
const GRState *state) {
Out << ' ';
if (Sym)
Out << Sym->getSymbolID();
else
Out << "<pool>";
Out << ":{";
// Get the contents of the pool.
if (const ARCounts *cnts = state->get<AutoreleasePoolContents>(Sym))
for (ARCounts::iterator J=cnts->begin(), EJ=cnts->end(); J != EJ; ++J)
Out << '(' << J.getKey() << ',' << J.getData() << ')';
Out << '}';
}
void CFRefCount::BindingsPrinter::Print(llvm::raw_ostream& Out,
const GRState* state,
const char* nl, const char* sep) {
RefBindings B = state->get<RefBindings>();
if (!B.isEmpty())
Out << sep << nl;
for (RefBindings::iterator I=B.begin(), E=B.end(); I!=E; ++I) {
Out << (*I).first << " : ";
(*I).second.print(Out);
Out << nl;
}
// Print the autorelease stack.
Out << sep << nl << "AR pool stack:";
ARStack stack = state->get<AutoreleaseStack>();
PrintPool(Out, SymbolRef(), state); // Print the caller's pool.
for (ARStack::iterator I=stack.begin(), E=stack.end(); I!=E; ++I)
PrintPool(Out, *I, state);
Out << nl;
}
//===----------------------------------------------------------------------===//
// Error reporting.
//===----------------------------------------------------------------------===//
namespace {
//===-------------===//
// Bug Descriptions. //
//===-------------===//
class CFRefBug : public BugType {
protected:
CFRefCount& TF;
CFRefBug(CFRefCount* tf, llvm::StringRef name)
: BugType(name, "Memory (Core Foundation/Objective-C)"), TF(*tf) {}
public:
CFRefCount& getTF() { return TF; }
// FIXME: Eventually remove.
virtual const char* getDescription() const = 0;
virtual bool isLeak() const { return false; }
};
class UseAfterRelease : public CFRefBug {
public:
UseAfterRelease(CFRefCount* tf)
: CFRefBug(tf, "Use-after-release") {}
const char* getDescription() const {
return "Reference-counted object is used after it is released";
}
};
class BadRelease : public CFRefBug {
public:
BadRelease(CFRefCount* tf) : CFRefBug(tf, "Bad release") {}
const char* getDescription() const {
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(CFRefCount *tf)
: CFRefBug(tf, "-dealloc called while using garbage collection") {}
const char *getDescription() const {
return "-dealloc called while using garbage collection";
}
};
class DeallocNotOwned : public CFRefBug {
public:
DeallocNotOwned(CFRefCount *tf)
: CFRefBug(tf, "-dealloc sent to non-exclusively owned object") {}
const char *getDescription() const {
return "-dealloc sent to object that may be referenced elsewhere";
}
};
class OverAutorelease : public CFRefBug {
public:
OverAutorelease(CFRefCount *tf) :
CFRefBug(tf, "Object sent -autorelease too many times") {}
const char *getDescription() const {
return "Object sent -autorelease too many times";
}
};
class ReturnedNotOwnedForOwned : public CFRefBug {
public:
ReturnedNotOwnedForOwned(CFRefCount *tf) :
CFRefBug(tf, "Method should return an owned object") {}
const char *getDescription() const {
return "Object with +0 retain counts returned to caller where a +1 "
"(owning) retain count is expected";
}
};
class Leak : public CFRefBug {
const bool isReturn;
protected:
Leak(CFRefCount* tf, llvm::StringRef name, bool isRet)
: CFRefBug(tf, name), isReturn(isRet) {}
public:
const char* getDescription() const { return ""; }
bool isLeak() const { return true; }
};
class LeakAtReturn : public Leak {
public:
LeakAtReturn(CFRefCount* tf, llvm::StringRef name)
: Leak(tf, name, true) {}
};
class LeakWithinFunction : public Leak {
public:
LeakWithinFunction(CFRefCount* tf, llvm::StringRef name)
: Leak(tf, name, false) {}
};
//===---------===//
// Bug Reports. //
//===---------===//
class CFRefReport : public RangedBugReport {
protected:
SymbolRef Sym;
const CFRefCount &TF;
public:
CFRefReport(CFRefBug& D, const CFRefCount &tf,
ExplodedNode *n, SymbolRef sym)
: RangedBugReport(D, D.getDescription(), n), Sym(sym), TF(tf) {}
CFRefReport(CFRefBug& D, const CFRefCount &tf,
ExplodedNode *n, SymbolRef sym, llvm::StringRef endText)
: RangedBugReport(D, D.getDescription(), endText, n), Sym(sym), TF(tf) {}
virtual ~CFRefReport() {}
CFRefBug& getBugType() {
return (CFRefBug&) RangedBugReport::getBugType();
}
virtual void getRanges(const SourceRange*& beg, const SourceRange*& end) {
if (!getBugType().isLeak())
RangedBugReport::getRanges(beg, end);
else
beg = end = 0;
}
SymbolRef getSymbol() const { return Sym; }
PathDiagnosticPiece* getEndPath(BugReporterContext& BRC,
const ExplodedNode* N);
std::pair<const char**,const char**> getExtraDescriptiveText();
PathDiagnosticPiece* VisitNode(const ExplodedNode* N,
const ExplodedNode* PrevN,
BugReporterContext& BRC);
};
class CFRefLeakReport : public CFRefReport {
SourceLocation AllocSite;
const MemRegion* AllocBinding;
public:
CFRefLeakReport(CFRefBug& D, const CFRefCount &tf,
ExplodedNode *n, SymbolRef sym,
GRExprEngine& Eng);
PathDiagnosticPiece* getEndPath(BugReporterContext& BRC,
const ExplodedNode* N);
SourceLocation getLocation() const { return AllocSite; }
};
} // end anonymous namespace
static const char* Msgs[] = {
// GC only
"Code is compiled to only use garbage collection",
// No GC.
"Code is compiled to use reference counts",
// Hybrid, with GC.
"Code is compiled to use either garbage collection (GC) or reference counts"
" (non-GC). The bug occurs with GC enabled",
// Hybrid, without GC
"Code is compiled to use either garbage collection (GC) or reference counts"
" (non-GC). The bug occurs in non-GC mode"
};
std::pair<const char**,const char**> CFRefReport::getExtraDescriptiveText() {
CFRefCount& TF = static_cast<CFRefBug&>(getBugType()).getTF();
switch (TF.getLangOptions().getGCMode()) {
default:
assert(false);
case LangOptions::GCOnly:
assert (TF.isGCEnabled());
return std::make_pair(&Msgs[0], &Msgs[0]+1);
case LangOptions::NonGC:
assert (!TF.isGCEnabled());
return std::make_pair(&Msgs[1], &Msgs[1]+1);
case LangOptions::HybridGC:
if (TF.isGCEnabled())
return std::make_pair(&Msgs[2], &Msgs[2]+1);
else
return std::make_pair(&Msgs[3], &Msgs[3]+1);
}
}
static inline bool contains(const llvm::SmallVectorImpl<ArgEffect>& V,
ArgEffect X) {
for (llvm::SmallVectorImpl<ArgEffect>::const_iterator I=V.begin(), E=V.end();
I!=E; ++I)
if (*I == X) return true;
return false;
}
PathDiagnosticPiece* CFRefReport::VisitNode(const ExplodedNode* N,
const ExplodedNode* PrevN,
BugReporterContext& BRC) {
if (!isa<PostStmt>(N->getLocation()))
return NULL;
// Check if the type state has changed.
const GRState *PrevSt = PrevN->getState();
const GRState *CurrSt = N->getState();
const RefVal* CurrT = CurrSt->get<RefBindings>(Sym);
if (!CurrT) return NULL;
const RefVal &CurrV = *CurrT;
const RefVal *PrevT = PrevSt->get<RefBindings>(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 = cast<PostStmt>(N->getLocation()).getStmt();
if (const CallExpr *CE = dyn_cast<CallExpr>(S)) {
// Get the name of the callee (if it is available).
SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee());
if (const FunctionDecl* FD = X.getAsFunctionDecl())
os << "Call to function '" << FD << '\'';
else
os << "function call";
}
else {
assert (isa<ObjCMessageExpr>(S));
os << "Method";
}
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 (owning reference).";
if (static_cast<CFRefBug&>(getBugType()).getTF().isGCEnabled()) {
assert(CurrV.getObjKind() == RetEffect::CF);
os << " "
"Core Foundation objects are not automatically garbage collected.";
}
}
else {
assert (CurrV.isNotOwned());
os << "+0 retain count (non-owning reference).";
}
PathDiagnosticLocation Pos(S, BRC.getSourceManager());
return new PathDiagnosticEventPiece(Pos, os.str());
}
// Gather up the effects that were performed on the object at this
// program point
llvm::SmallVector<ArgEffect, 2> AEffects;
if (const RetainSummary *Summ =
TF.getSummaryOfNode(BRC.getNodeResolver().getOriginalNode(N))) {
// We only have summaries attached to nodes after evaluating CallExpr and
// ObjCMessageExprs.
const Stmt* S = cast<PostStmt>(N->getLocation()).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).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).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 (!TF.isGCEnabled() && contains(AEffects, Dealloc)) {
// Determine if the object's reference count was pushed to zero.
assert(!(PrevV == CurrV) && "The typestate *must* 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 (contains(AEffects, MakeCollectable)) {
// Get the name of the function.
const Stmt* S = cast<PostStmt>(N->getLocation()).getStmt();
SVal X = CurrSt->getSValAsScalarOrLoc(cast<CallExpr>(S)->getCallee());
const FunctionDecl* FD = X.getAsFunctionDecl();
const std::string& FName = FD->getNameAsString();
if (TF.isGCEnabled()) {
// Determine if the object's reference count was pushed to zero.
assert(!(PrevV == CurrV) && "The typestate *must* have changed.");
os << "In GC mode a call to '" << FName
<< "' 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 '" << FName
<< "' has no effect on its argument.";
// Nothing more to say.
break;
}
// Determine if the typestate has changed.
if (!(PrevV == 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 0;
assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount());
os << "Object sent -autorelease message";
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(TF.isGCEnabled() && CurrV.getCount() > 0);
os << " The object is not eligible for garbage collection until the "
"retain count reaches 0 again.";
}
break;
case RefVal::Released:
os << "Object released.";
break;
case RefVal::ReturnedOwned:
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 (non-owning) retain count.";
break;
default:
return NULL;
}
// Emit any remaining diagnostics for the argument effects (if any).
for (llvm::SmallVectorImpl<ArgEffect>::iterator I=AEffects.begin(),
E=AEffects.end(); I != E; ++I) {
// A bunch of things have alternate behavior under GC.
if (TF.isGCEnabled())
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 0; // We have nothing to say!
const Stmt* S = cast<PostStmt>(N->getLocation()).getStmt();
PathDiagnosticLocation Pos(S, BRC.getSourceManager());
PathDiagnosticPiece* P = new PathDiagnosticEventPiece(Pos, os.str());
// Add the range by scanning the children of the statement for any bindings
// to Sym.
for (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end();
I!=E; ++I)
if (const Expr* Exp = dyn_cast_or_null<Expr>(*I))
if (CurrSt->getSValAsScalarOrLoc(Exp).getAsLocSymbol() == Sym) {
P->addRange(Exp->getSourceRange());
break;
}
return P;
}
namespace {
class FindUniqueBinding :
public StoreManager::BindingsHandler {
SymbolRef Sym;
const MemRegion* Binding;
bool First;
public:
FindUniqueBinding(SymbolRef sym) : Sym(sym), Binding(0), First(true) {}
bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R,
SVal val) {
SymbolRef SymV = val.getAsSymbol();
if (!SymV || SymV != Sym)
return true;
if (Binding) {
First = false;
return false;
}
else
Binding = R;
return true;
}
operator bool() { return First && Binding; }
const MemRegion* getRegion() { return Binding; }
};
}
static std::pair<const ExplodedNode*,const MemRegion*>
GetAllocationSite(GRStateManager& StateMgr, const ExplodedNode* N,
SymbolRef Sym) {
// Find both first node that referred to the tracked symbol and the
// memory location that value was store to.
const ExplodedNode* Last = N;
const MemRegion* FirstBinding = 0;
while (N) {
const GRState* St = N->getState();
RefBindings B = St->get<RefBindings>();
if (!B.lookup(Sym))
break;
FindUniqueBinding FB(Sym);
StateMgr.iterBindings(St, FB);
if (FB) FirstBinding = FB.getRegion();
Last = N;
N = N->pred_empty() ? NULL : *(N->pred_begin());
}
return std::make_pair(Last, FirstBinding);
}
PathDiagnosticPiece*
CFRefReport::getEndPath(BugReporterContext& BRC,
const ExplodedNode* EndN) {
// Tell the BugReporterContext to report cases when the tracked symbol is
// assigned to different variables, etc.
BRC.addNotableSymbol(Sym);
return RangedBugReport::getEndPath(BRC, EndN);
}
PathDiagnosticPiece*
CFRefLeakReport::getEndPath(BugReporterContext& BRC,
const ExplodedNode* EndN){
// Tell the BugReporterContext to report cases when the tracked symbol is
// assigned to different variables, etc.
BRC.addNotableSymbol(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.
const ExplodedNode* AllocNode = 0;
const MemRegion* FirstBinding = 0;
llvm::tie(AllocNode, FirstBinding) =
GetAllocationSite(BRC.getStateManager(), EndN, Sym);
// Get the allocate site.
assert(AllocNode);
const Stmt* FirstStmt = cast<PostStmt>(AllocNode->getLocation()).getStmt();
SourceManager& SMgr = BRC.getSourceManager();
unsigned AllocLine =SMgr.getInstantiationLineNumber(FirstStmt->getLocStart());
// 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;
while (LeakN) {
ProgramPoint P = LeakN->getLocation();
if (const PostStmt *PS = dyn_cast<PostStmt>(&P)) {
L = PathDiagnosticLocation(PS->getStmt()->getLocStart(), SMgr);
break;
}
else if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P)) {
if (const Stmt* Term = BE->getSrc()->getTerminator()) {
L = PathDiagnosticLocation(Term->getLocStart(), SMgr);
break;
}
}
LeakN = LeakN->succ_empty() ? 0 : *(LeakN->succ_begin());
}
if (!L.isValid()) {
const Decl &D = EndN->getCodeDecl();
L = PathDiagnosticLocation(D.getBodyRBrace(), SMgr);
}
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
os << "Object allocated on line " << AllocLine;
if (FirstBinding)
os << " and stored into '" << FirstBinding->getString() << '\'';
// Get the retain count.
const RefVal* RV = EndN->getState()->get<RefBindings>(Sym);
if (RV->getKind() == RefVal::ErrorLeakReturned) {
// FIXME: Per comments in rdar://6320065, "create" only applies to CF
// ojbects. Only "copy", "alloc", "retain" and "new" transfer ownership
// to the caller for NS objects.
ObjCMethodDecl& MD = cast<ObjCMethodDecl>(EndN->getCodeDecl());
os << " is returned from a method whose name ('"
<< MD.getSelector().getAsString()
<< "') does not contain 'copy' or otherwise starts with"
" 'new' or 'alloc'. This violates the naming convention rules given"
" in the Memory Management Guide for Cocoa (object leaked)";
}
else if (RV->getKind() == RefVal::ErrorGCLeakReturned) {
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 no longer referenced after this point and has a retain count of"
" +" << RV->getCount() << " (object leaked)";
return new PathDiagnosticEventPiece(L, os.str());
}
CFRefLeakReport::CFRefLeakReport(CFRefBug& D, const CFRefCount &tf,
ExplodedNode *n,
SymbolRef sym, GRExprEngine& Eng)
: CFRefReport(D, tf, n, sym) {
// Most bug reports are cached at the location where they occured.
// 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 = 0;
llvm::tie(AllocNode, AllocBinding) = // Set AllocBinding.
GetAllocationSite(Eng.getStateManager(), getEndNode(), getSymbol());
// Get the SourceLocation for the allocation site.
ProgramPoint P = AllocNode->getLocation();
AllocSite = cast<PostStmt>(P).getStmt()->getLocStart();
// Fill in the description of the bug.
Description.clear();
llvm::raw_string_ostream os(Description);
SourceManager& SMgr = Eng.getContext().getSourceManager();
unsigned AllocLine = SMgr.getInstantiationLineNumber(AllocSite);
os << "Potential leak ";
if (tf.isGCEnabled()) {
os << "(when using garbage collection) ";
}
os << "of an object allocated on line " << AllocLine;
// FIXME: AllocBinding doesn't get populated for RegionStore yet.
if (AllocBinding)
os << " and stored into '" << AllocBinding->getString() << '\'';
}
//===----------------------------------------------------------------------===//
// Main checker logic.
//===----------------------------------------------------------------------===//
/// 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 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).
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;
}
void CFRefCount::EvalSummary(ExplodedNodeSet& Dst,
GRExprEngine& Eng,
GRStmtNodeBuilder& Builder,
const Expr* Ex,
InstanceReceiver Receiver,
const RetainSummary& Summ,
const MemRegion *Callee,
ConstExprIterator arg_beg,
ConstExprIterator arg_end,
ExplodedNode* Pred, const GRState *state) {
// Evaluate the effect of the arguments.
RefVal::Kind hasErr = (RefVal::Kind) 0;
unsigned idx = 0;
SourceRange ErrorRange;
SymbolRef ErrorSym = 0;
llvm::SmallVector<const MemRegion*, 10> RegionsToInvalidate;
// HACK: Symbols that have ref-count state that are referenced directly
// (not as structure or array elements, or via bindings) by an argument
// should not have their ref-count state stripped after we have
// done an invalidation pass.
llvm::DenseSet<SymbolRef> WhitelistedSymbols;
for (ConstExprIterator I = arg_beg; I != arg_end; ++I, ++idx) {
SVal V = state->getSValAsScalarOrLoc(*I);
SymbolRef Sym = V.getAsLocSymbol();
if (Sym)
if (RefBindings::data_type* T = state->get<RefBindings>(Sym)) {
WhitelistedSymbols.insert(Sym);
state = Update(state, Sym, *T, Summ.getArg(idx), hasErr);
if (hasErr) {
ErrorRange = (*I)->getSourceRange();
ErrorSym = Sym;
break;
}
}
tryAgain:
if (isa<Loc>(V)) {
if (loc::MemRegionVal* MR = dyn_cast<loc::MemRegionVal>(&V)) {
if (Summ.getArg(idx) == DoNothingByRef)
continue;
// Invalidate the value of the variable passed by reference.
const MemRegion *R = MR->getRegion();
// Are we dealing with an ElementRegion? If the element type is
// a basic integer type (e.g., char, int) and the underying region
// is a variable region then strip off the ElementRegion.
// FIXME: We really need to think about this for the general case
// as sometimes we are reasoning about arrays and other times
// about (char*), etc., is just a form of passing raw bytes.
// e.g., void *p = alloca(); foo((char*)p);
if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
// Checking for 'integral type' is probably too promiscuous, but
// we'll leave it in for now until we have a systematic way of
// handling all of these cases. Eventually we need to come up
// with an interface to StoreManager so that this logic can be
// approriately delegated to the respective StoreManagers while
// still allowing us to do checker-specific logic (e.g.,
// invalidating reference counts), probably via callbacks.
if (ER->getElementType()->isIntegralOrEnumerationType()) {
const MemRegion *superReg = ER->getSuperRegion();
if (isa<VarRegion>(superReg) || isa<FieldRegion>(superReg) ||
isa<ObjCIvarRegion>(superReg))
R = cast<TypedRegion>(superReg);
}
// FIXME: What about layers of ElementRegions?
}
// Mark this region for invalidation. We batch invalidate regions
// below for efficiency.
RegionsToInvalidate.push_back(R);
continue;
}
else {
// Nuke all other arguments passed by reference.
// FIXME: is this necessary or correct? This handles the non-Region
// cases. Is it ever valid to store to these?
state = state->unbindLoc(cast<Loc>(V));
}
}
else if (isa<nonloc::LocAsInteger>(V)) {
// If we are passing a location wrapped as an integer, unwrap it and
// invalidate the values referred by the location.
V = cast<nonloc::LocAsInteger>(V).getLoc();
goto tryAgain;
}
}
// Block calls result in all captured values passed-via-reference to be
// invalidated.
if (const BlockDataRegion *BR = dyn_cast_or_null<BlockDataRegion>(Callee)) {
RegionsToInvalidate.push_back(BR);
}
// Invalidate regions we designed for invalidation use the batch invalidation
// API.
// FIXME: We can have collisions on the conjured symbol if the
// expression *I also creates conjured symbols. We probably want
// to identify conjured symbols by an expression pair: the enclosing
// expression (the context) and the expression itself. This should
// disambiguate conjured symbols.
unsigned Count = Builder.getCurrentBlockCount();
StoreManager::InvalidatedSymbols IS;
// NOTE: Even if RegionsToInvalidate is empty, we must still invalidate
// global variables.
state = state->InvalidateRegions(RegionsToInvalidate.data(),
RegionsToInvalidate.data() +
RegionsToInvalidate.size(),
Ex, Count, &IS,
/* invalidateGlobals = */ true);
for (StoreManager::InvalidatedSymbols::iterator I = IS.begin(),
E = IS.end(); I!=E; ++I) {
SymbolRef sym = *I;
if (WhitelistedSymbols.count(sym))
continue;
// Remove any existing reference-count binding.
state = state->remove<RefBindings>(*I);
}
// Evaluate the effect on the message receiver.
if (!ErrorRange.isValid() && Receiver) {
SymbolRef Sym = Receiver.getSValAsScalarOrLoc(state).getAsLocSymbol();
if (Sym) {
if (const RefVal* T = state->get<RefBindings>(Sym)) {
state = Update(state, Sym, *T, Summ.getReceiverEffect(), hasErr);
if (hasErr) {
ErrorRange = Receiver.getSourceRange();
ErrorSym = Sym;
}
}
}
}
// Process any errors.
if (hasErr) {
ProcessNonLeakError(Dst, Builder, Ex, ErrorRange, Pred, state,
hasErr, ErrorSym);
return;
}
// Consult the summary for the return value.
RetEffect RE = Summ.getRetEffect();
if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) {
bool found = false;
if (Receiver) {
SVal V = Receiver.getSValAsScalarOrLoc(state);
if (SymbolRef Sym = V.getAsLocSymbol())
if (state->get<RefBindings>(Sym)) {
found = true;
RE = Summaries.getObjAllocRetEffect();
}
} // FIXME: Otherwise, this is a send-to-super instance message.
if (!found)
RE = RetEffect::MakeNoRet();
}
switch (RE.getKind()) {
default:
assert (false && "Unhandled RetEffect."); break;
case RetEffect::NoRet: {
// Make up a symbol for the return value (not reference counted).
// FIXME: Most of this logic is not specific to the retain/release
// checker.
// FIXME: We eventually should handle structs and other compound types
// that are returned by value.
QualType T = Ex->getType();
// For CallExpr, use the result type to know if it returns a reference.
if (const CallExpr *CE = dyn_cast<CallExpr>(Ex)) {
const Expr *Callee = CE->getCallee();
if (const FunctionDecl *FD = state->getSVal(Callee).getAsFunctionDecl())
T = FD->getResultType();
}
else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(Ex)) {
if (const ObjCMethodDecl *MD = ME->getMethodDecl())
T = MD->getResultType();
}
if (Loc::IsLocType(T) || (T->isIntegerType() && T->isScalarType())) {
unsigned Count = Builder.getCurrentBlockCount();
ValueManager &ValMgr = Eng.getValueManager();
SVal X = ValMgr.getConjuredSymbolVal(NULL, Ex, T, Count);
state = state->BindExpr(Ex, X, false);
}
break;
}
case RetEffect::Alias: {
unsigned idx = RE.getIndex();
assert (arg_end >= arg_beg);
assert (idx < (unsigned) (arg_end - arg_beg));
SVal V = state->getSValAsScalarOrLoc(*(arg_beg+idx));
state = state->BindExpr(Ex, V, false);
break;
}
case RetEffect::ReceiverAlias: {
assert(Receiver);
SVal V = Receiver.getSValAsScalarOrLoc(state);
state = state->BindExpr(Ex, V, false);
break;
}
case RetEffect::OwnedAllocatedSymbol:
case RetEffect::OwnedSymbol: {
unsigned Count = Builder.getCurrentBlockCount();
ValueManager &ValMgr = Eng.getValueManager();
SymbolRef Sym = ValMgr.getConjuredSymbol(Ex, Count);
QualType RetT = GetReturnType(Ex, ValMgr.getContext());
state = state->set<RefBindings>(Sym, RefVal::makeOwned(RE.getObjKind(),
RetT));
state = state->BindExpr(Ex, ValMgr.makeLoc(Sym), false);
// FIXME: Add a flag to the checker where allocations are assumed to
// *not fail.
#if 0
if (RE.getKind() == RetEffect::OwnedAllocatedSymbol) {
bool isFeasible;
state = state.Assume(loc::SymbolVal(Sym), true, isFeasible);
assert(isFeasible && "Cannot assume fresh symbol is non-null.");
}
#endif
break;
}
case RetEffect::GCNotOwnedSymbol:
case RetEffect::NotOwnedSymbol: {
unsigned Count = Builder.getCurrentBlockCount();
ValueManager &ValMgr = Eng.getValueManager();
SymbolRef Sym = ValMgr.getConjuredSymbol(Ex, Count);
QualType RetT = GetReturnType(Ex, ValMgr.getContext());
state = state->set<RefBindings>(Sym, RefVal::makeNotOwned(RE.getObjKind(),
RetT));
state = state->BindExpr(Ex, ValMgr.makeLoc(Sym), false);
break;
}
}
// Generate a sink node if we are at the end of a path.
ExplodedNode *NewNode =
Summ.isEndPath() ? Builder.MakeSinkNode(Dst, Ex, Pred, state)
: Builder.MakeNode(Dst, Ex, Pred, state);
// Annotate the edge with summary we used.
if (NewNode) SummaryLog[NewNode] = &Summ;
}
void CFRefCount::EvalCall(ExplodedNodeSet& Dst,
GRExprEngine& Eng,
GRStmtNodeBuilder& Builder,
const CallExpr* CE, SVal L,
ExplodedNode* Pred) {
RetainSummary *Summ = 0;
// FIXME: Better support for blocks. For now we stop tracking anything
// that is passed to blocks.
// FIXME: Need to handle variables that are "captured" by the block.
if (dyn_cast_or_null<BlockDataRegion>(L.getAsRegion())) {
Summ = Summaries.getPersistentStopSummary();
}
else {
const FunctionDecl* FD = L.getAsFunctionDecl();
Summ = !FD ? Summaries.getDefaultSummary() :
Summaries.getSummary(FD);
}
assert(Summ);
EvalSummary(Dst, Eng, Builder, CE, 0, *Summ, L.getAsRegion(),
CE->arg_begin(), CE->arg_end(), Pred, Builder.GetState(Pred));
}
void CFRefCount::EvalObjCMessageExpr(ExplodedNodeSet& Dst,
GRExprEngine& Eng,
GRStmtNodeBuilder& Builder,
const ObjCMessageExpr* ME,
ExplodedNode* Pred,
const GRState *state) {
RetainSummary *Summ =
ME->isInstanceMessage()
? Summaries.getInstanceMethodSummary(ME, state,Pred->getLocationContext())
: Summaries.getClassMethodSummary(ME);
assert(Summ && "RetainSummary is null");
EvalSummary(Dst, Eng, Builder, ME,
InstanceReceiver(ME, Pred->getLocationContext()), *Summ, NULL,
ME->arg_begin(), ME->arg_end(), Pred, state);
}
namespace {
class StopTrackingCallback : public SymbolVisitor {
const GRState *state;
public:
StopTrackingCallback(const GRState *st) : state(st) {}
const GRState *getState() const { return state; }
bool VisitSymbol(SymbolRef sym) {
state = state->remove<RefBindings>(sym);
return true;
}
};
} // end anonymous namespace
void CFRefCount::EvalBind(GRStmtNodeBuilderRef& B, SVal location, SVal val) {
// Are we storing to something that causes the value to "escape"?
bool escapes = false;
// 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.
const GRState *state = B.getState();
if (!isa<loc::MemRegionVal>(location))
escapes = true;
else {
const MemRegion* R = cast<loc::MemRegionVal>(location).getRegion();
escapes = !R->hasStackStorage();
if (!escapes) {
// To test (3), generate a new state with the binding removed. If it is
// the same state, then it escapes (since the store cannot represent
// the binding).
escapes = (state == (state->bindLoc(cast<Loc>(location), UnknownVal())));
}
}
// 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.
B.MakeNode(state->scanReachableSymbols<StopTrackingCallback>(val).getState());
}
// Return statements.
void CFRefCount::EvalReturn(ExplodedNodeSet& Dst,
GRExprEngine& Eng,
GRStmtNodeBuilder& Builder,
const ReturnStmt* S,
ExplodedNode* Pred) {
const Expr* RetE = S->getRetValue();
if (!RetE)
return;
const GRState *state = Builder.GetState(Pred);
SymbolRef Sym = state->getSValAsScalarOrLoc(RetE).getAsLocSymbol();
if (!Sym)
return;
// Get the reference count binding (if any).
const RefVal* T = state->get<RefBindings>(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 = state->set<RefBindings>(Sym, X);
Pred = Builder.MakeNode(Dst, S, Pred, state);
// Did we cache out?
if (!Pred)
return;
// Update the autorelease counts.
static unsigned autoreleasetag = 0;
GenericNodeBuilder Bd(Builder, S, &autoreleasetag);
bool stop = false;
llvm::tie(Pred, state) = HandleAutoreleaseCounts(state , Bd, Pred, Eng, Sym,
X, stop);
// Did we cache out?
if (!Pred || stop)
return;
// Get the updated binding.
T = state->get<RefBindings>(Sym);
assert(T);
X = *T;
// Any leaks or other errors?
if (X.isReturnedOwned() && X.getCount() == 0) {
Decl const *CD = &Pred->getCodeDecl();
if (const ObjCMethodDecl* MD = dyn_cast<ObjCMethodDecl>(CD)) {
const RetainSummary &Summ = *Summaries.getMethodSummary(MD);
RetEffect RE = Summ.getRetEffect();
bool hasError = false;
if (RE.getKind() != RetEffect::NoRet) {
if (isGCEnabled() && 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.
static int ReturnOwnLeakTag = 0;
state = state->set<RefBindings>(Sym, X);
ExplodedNode *N =
Builder.generateNode(PostStmt(S, Pred->getLocationContext(),
&ReturnOwnLeakTag), state, Pred);
if (N) {
CFRefReport *report =
new CFRefLeakReport(*static_cast<CFRefBug*>(leakAtReturn), *this,
N, Sym, Eng);
BR->EmitReport(report);
}
}
}
}
else if (X.isReturnedNotOwned()) {
Decl const *CD = &Pred->getCodeDecl();
if (const ObjCMethodDecl* MD = dyn_cast<ObjCMethodDecl>(CD)) {
const RetainSummary &Summ = *Summaries.getMethodSummary(MD);
if (Summ.getRetEffect().isOwned()) {
// Trying to return a not owned object to a caller expecting an
// owned object.
static int ReturnNotOwnedForOwnedTag = 0;
state = state->set<RefBindings>(Sym, X ^ RefVal::ErrorReturnedNotOwned);
if (ExplodedNode *N =
Builder.generateNode(PostStmt(S, Pred->getLocationContext(),
&ReturnNotOwnedForOwnedTag),
state, Pred)) {
CFRefReport *report =
new CFRefReport(*static_cast<CFRefBug*>(returnNotOwnedForOwned),
*this, N, Sym);
BR->EmitReport(report);
}
}
}
}
}
// Assumptions.
const GRState* CFRefCount::EvalAssume(const GRState *state,
SVal Cond, bool Assumption) {
// 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.
RefBindings B = state->get<RefBindings>();
if (B.isEmpty())
return state;
bool changed = false;
RefBindings::Factory& RefBFactory = state->get_context<RefBindings>();
for (RefBindings::iterator I=B.begin(), E=B.end(); I!=E; ++I) {
// Check if the symbol is null (or equal to any constant).
// If this is the case, stop tracking the symbol.
if (state->getSymVal(I.getKey())) {
changed = true;
B = RefBFactory.Remove(B, I.getKey());
}
}
if (changed)
state = state->set<RefBindings>(B);
return state;
}
const GRState * CFRefCount::Update(const GRState * state, SymbolRef sym,
RefVal V, ArgEffect E,
RefVal::Kind& hasErr) {
// In GC mode [... release] and [... retain] do nothing.
switch (E) {
default: break;
case IncRefMsg: E = isGCEnabled() ? DoNothing : IncRef; break;
case DecRefMsg: E = isGCEnabled() ? DoNothing : DecRef; break;
case MakeCollectable: E = isGCEnabled() ? DecRef : DoNothing; break;
case NewAutoreleasePool: E = isGCEnabled() ? DoNothing :
NewAutoreleasePool; break;
}
// Handle all use-after-releases.
if (!isGCEnabled() && V.getKind() == RefVal::Released) {
V = V ^ RefVal::ErrorUseAfterRelease;
hasErr = V.getKind();
return state->set<RefBindings>(sym, V);
}
switch (E) {
default:
assert (false && "Unhandled CFRef transition.");
case Dealloc:
// Any use of -dealloc in GC is *bad*.
if (isGCEnabled()) {
V = V ^ RefVal::ErrorDeallocGC;
hasErr = V.getKind();
break;
}
switch (V.getKind()) {
default:
assert(false && "Invalid case.");
case RefVal::Owned:
// The object immediately transitions to the released state.
V = V ^ RefVal::Released;
V.clearCounts();
return state->set<RefBindings>(sym, V);
case RefVal::NotOwned:
V = V ^ RefVal::ErrorDeallocNotOwned;
hasErr = V.getKind();
break;
}
break;
case NewAutoreleasePool:
assert(!isGCEnabled());
return state->add<AutoreleaseStack>(sym);
case MayEscape:
if (V.getKind() == RefVal::Owned) {
V = V ^ RefVal::NotOwned;
break;
}
// Fall-through.
case DoNothingByRef:
case DoNothing:
return state;
case Autorelease:
if (isGCEnabled())
return state;
// Update the autorelease counts.
state = SendAutorelease(state, ARCountFactory, sym);
V = V.autorelease();
break;
case StopTracking:
return state->remove<RefBindings>(sym);
case IncRef:
switch (V.getKind()) {
default:
assert(false);
case RefVal::Owned:
case RefVal::NotOwned:
V = V + 1;
break;
case RefVal::Released:
// Non-GC cases are handled above.
assert(isGCEnabled());
V = (V ^ RefVal::Owned) + 1;
break;
}
break;
case SelfOwn:
V = V ^ RefVal::NotOwned;
// Fall-through.
case DecRef:
switch (V.getKind()) {
default:
// case 'RefVal::Released' handled above.
assert (false);
case RefVal::Owned:
assert(V.getCount() > 0);
if (V.getCount() == 1) V = V ^ RefVal::Released;
V = V - 1;
break;
case RefVal::NotOwned:
if (V.getCount() > 0)
V = V - 1;
else {
V = V ^ RefVal::ErrorReleaseNotOwned;
hasErr = V.getKind();
}
break;
case RefVal::Released:
// Non-GC cases are handled above.
assert(isGCEnabled());
V = V ^ RefVal::ErrorUseAfterRelease;
hasErr = V.getKind();
break;
}
break;
}
return state->set<RefBindings>(sym, V);
}
//===----------------------------------------------------------------------===//
// Handle dead symbols and end-of-path.
//===----------------------------------------------------------------------===//
std::pair<ExplodedNode*, const GRState *>
CFRefCount::HandleAutoreleaseCounts(const GRState * state, GenericNodeBuilder Bd,
ExplodedNode* Pred,
GRExprEngine &Eng,
SymbolRef Sym, RefVal V, bool &stop) {
unsigned ACnt = V.getAutoreleaseCount();
stop = false;
// No autorelease counts? Nothing to be done.
if (!ACnt)
return std::make_pair(Pred, state);
assert(!isGCEnabled() && "Autorelease counts in GC mode?");
unsigned Cnt = V.getCount();
// FIXME: Handle sending 'autorelease' to already released object.
if (V.getKind() == RefVal::ReturnedOwned)
++Cnt;
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(Cnt - ACnt);
V.setAutoreleaseCount(0);
}
state = state->set<RefBindings>(Sym, V);
ExplodedNode *N = Bd.MakeNode(state, Pred);
stop = (N == 0);
return std::make_pair(N, state);
}
// Woah! More autorelease counts then retain counts left.
// Emit hard error.
stop = true;
V = V ^ RefVal::ErrorOverAutorelease;
state = state->set<RefBindings>(Sym, V);
if (ExplodedNode *N = Bd.MakeNode(state, Pred)) {
N->markAsSink();
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
os << "Object over-autoreleased: object was sent -autorelease";
if (V.getAutoreleaseCount() > 1)
os << V.getAutoreleaseCount() << " times";
os << " but the object has ";
if (V.getCount() == 0)
os << "zero (locally visible)";
else
os << "+" << V.getCount();
os << " retain counts";
CFRefReport *report =
new CFRefReport(*static_cast<CFRefBug*>(overAutorelease),
*this, N, Sym, os.str());
BR->EmitReport(report);
}
return std::make_pair((ExplodedNode*)0, state);
}
const GRState *
CFRefCount::HandleSymbolDeath(const GRState * state, SymbolRef sid, RefVal V,
llvm::SmallVectorImpl<SymbolRef> &Leaked) {
bool hasLeak = V.isOwned() ||
((V.isNotOwned() || V.isReturnedOwned()) && V.getCount() > 0);
if (!hasLeak)
return state->remove<RefBindings>(sid);
Leaked.push_back(sid);
return state->set<RefBindings>(sid, V ^ RefVal::ErrorLeak);
}
ExplodedNode*
CFRefCount::ProcessLeaks(const GRState * state,
llvm::SmallVectorImpl<SymbolRef> &Leaked,
GenericNodeBuilder &Builder,
GRExprEngine& Eng,
ExplodedNode *Pred) {
if (Leaked.empty())
return Pred;
// Generate an intermediate node representing the leak point.
ExplodedNode *N = Builder.MakeNode(state, Pred);
if (N) {
for (llvm::SmallVectorImpl<SymbolRef>::iterator
I = Leaked.begin(), E = Leaked.end(); I != E; ++I) {
CFRefBug *BT = static_cast<CFRefBug*>(Pred ? leakWithinFunction
: leakAtReturn);
assert(BT && "BugType not initialized.");
CFRefLeakReport* report = new CFRefLeakReport(*BT, *this, N, *I, Eng);
BR->EmitReport(report);
}
}
return N;
}
void CFRefCount::EvalEndPath(GRExprEngine& Eng,
GREndPathNodeBuilder& Builder) {
const GRState *state = Builder.getState();
GenericNodeBuilder Bd(Builder);
RefBindings B = state->get<RefBindings>();
ExplodedNode *Pred = 0;
for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) {
bool stop = false;
llvm::tie(Pred, state) = HandleAutoreleaseCounts(state, Bd, Pred, Eng,
(*I).first,
(*I).second, stop);
if (stop)
return;
}
B = state->get<RefBindings>();
llvm::SmallVector<SymbolRef, 10> Leaked;
for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I)
state = HandleSymbolDeath(state, (*I).first, (*I).second, Leaked);
ProcessLeaks(state, Leaked, Bd, Eng, Pred);
}
void CFRefCount::EvalDeadSymbols(ExplodedNodeSet& Dst,
GRExprEngine& Eng,
GRStmtNodeBuilder& Builder,
ExplodedNode* Pred,
const GRState* state,
SymbolReaper& SymReaper) {
const Stmt *S = Builder.getStmt();
RefBindings B = state->get<RefBindings>();
// 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.
GenericNodeBuilder Bd(Builder, S, Sym);
bool stop = false;
llvm::tie(Pred, state) = HandleAutoreleaseCounts(state, Bd, Pred, Eng,
Sym, *T, stop);
if (stop)
return;
}
}
B = state->get<RefBindings>();
llvm::SmallVector<SymbolRef, 10> Leaked;
for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(),
E = SymReaper.dead_end(); I != E; ++I) {
if (const RefVal* T = B.lookup(*I))
state = HandleSymbolDeath(state, *I, *T, Leaked);
}
static unsigned LeakPPTag = 0;
{
GenericNodeBuilder Bd(Builder, S, &LeakPPTag);
Pred = ProcessLeaks(state, Leaked, Bd, Eng, Pred);
}
// Did we cache out?
if (!Pred)
return;
// Now generate a new node that nukes the old bindings.
RefBindings::Factory& F = state->get_context<RefBindings>();
for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(),
E = SymReaper.dead_end(); I!=E; ++I) B = F.Remove(B, *I);
state = state->set<RefBindings>(B);
Builder.MakeNode(Dst, S, Pred, state);
}
void CFRefCount::ProcessNonLeakError(ExplodedNodeSet& Dst,
GRStmtNodeBuilder& Builder,
const Expr* NodeExpr,
SourceRange ErrorRange,
ExplodedNode* Pred,
const GRState* St,
RefVal::Kind hasErr, SymbolRef Sym) {
Builder.BuildSinks = true;
ExplodedNode *N = Builder.MakeNode(Dst, NodeExpr, Pred, St);
if (!N)
return;
CFRefBug *BT = 0;
switch (hasErr) {
default:
assert(false && "Unhandled error.");
return;
case RefVal::ErrorUseAfterRelease:
BT = static_cast<CFRefBug*>(useAfterRelease);
break;
case RefVal::ErrorReleaseNotOwned:
BT = static_cast<CFRefBug*>(releaseNotOwned);
break;
case RefVal::ErrorDeallocGC:
BT = static_cast<CFRefBug*>(deallocGC);
break;
case RefVal::ErrorDeallocNotOwned:
BT = static_cast<CFRefBug*>(deallocNotOwned);
break;
}
CFRefReport *report = new CFRefReport(*BT, *this, N, Sym);
report->addRange(ErrorRange);
BR->EmitReport(report);
}
//===----------------------------------------------------------------------===//
// Pieces of the retain/release checker implemented using a CheckerVisitor.
// More pieces of the retain/release checker will be migrated to this interface
// (ideally, all of it some day).
//===----------------------------------------------------------------------===//
namespace {
class RetainReleaseChecker
: public CheckerVisitor<RetainReleaseChecker> {
CFRefCount *TF;
public:
RetainReleaseChecker(CFRefCount *tf) : TF(tf) {}
static void* getTag() { static int x = 0; return &x; }
void PostVisitBlockExpr(CheckerContext &C, const BlockExpr *BE);
};
} // end anonymous namespace
void RetainReleaseChecker::PostVisitBlockExpr(CheckerContext &C,
const BlockExpr *BE) {
// Scan the BlockDecRefExprs for any object the retain/release checker
// may be tracking.
if (!BE->hasBlockDeclRefExprs())
return;
const GRState *state = C.getState();
const BlockDataRegion *R =
cast<BlockDataRegion>(state->getSVal(BE).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.
llvm::SmallVector<const MemRegion*, 10> Regions;
const LocationContext *LC = C.getPredecessor()->getLocationContext();
MemRegionManager &MemMgr = C.getValueManager().getRegionManager();
for ( ; I != E; ++I) {
const VarRegion *VR = *I;
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);
}
//===----------------------------------------------------------------------===//
// Transfer function creation for external clients.
//===----------------------------------------------------------------------===//
void CFRefCount::RegisterChecks(GRExprEngine& Eng) {
BugReporter &BR = Eng.getBugReporter();
useAfterRelease = new UseAfterRelease(this);
BR.Register(useAfterRelease);
releaseNotOwned = new BadRelease(this);
BR.Register(releaseNotOwned);
deallocGC = new DeallocGC(this);
BR.Register(deallocGC);
deallocNotOwned = new DeallocNotOwned(this);
BR.Register(deallocNotOwned);
overAutorelease = new OverAutorelease(this);
BR.Register(overAutorelease);
returnNotOwnedForOwned = new ReturnedNotOwnedForOwned(this);
BR.Register(returnNotOwnedForOwned);
// First register "return" leaks.
const char* name = 0;
if (isGCEnabled())
name = "Leak of returned object when using garbage collection";
else if (getLangOptions().getGCMode() == LangOptions::HybridGC)
name = "Leak of returned object when not using garbage collection (GC) in "
"dual GC/non-GC code";
else {
assert(getLangOptions().getGCMode() == LangOptions::NonGC);
name = "Leak of returned object";
}
// Leaks should not be reported if they are post-dominated by a sink.
leakAtReturn = new LeakAtReturn(this, name);
leakAtReturn->setSuppressOnSink(true);
BR.Register(leakAtReturn);
// Second, register leaks within a function/method.
if (isGCEnabled())
name = "Leak of object when using garbage collection";
else if (getLangOptions().getGCMode() == LangOptions::HybridGC)
name = "Leak of object when not using garbage collection (GC) in "
"dual GC/non-GC code";
else {
assert(getLangOptions().getGCMode() == LangOptions::NonGC);
name = "Leak";
}
// Leaks should not be reported if they are post-dominated by sinks.
leakWithinFunction = new LeakWithinFunction(this, name);
leakWithinFunction->setSuppressOnSink(true);
BR.Register(leakWithinFunction);
// Save the reference to the BugReporter.
this->BR = &BR;
// Register the RetainReleaseChecker with the GRExprEngine object.
// Functionality in CFRefCount will be migrated to RetainReleaseChecker
// over time.
Eng.registerCheck(new RetainReleaseChecker(this));
}
GRTransferFuncs* clang::MakeCFRefCountTF(ASTContext& Ctx, bool GCEnabled,
const LangOptions& lopts) {
return new CFRefCount(Ctx, GCEnabled, lopts);
}
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