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gerrit-public.fairphone.software / platform / external / clang / 927686fe8c968ca786fa44d2353eebf59c4f5b8a / . / lib / Analysis / CFRefCount.cpp
blob: 7a9d608b71ce496109a2734c09846eed4d8c1fb0 [file] [log] [blame]
// 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 "GRSimpleVals.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Analysis/PathSensitive/ValueState.h"
#include "clang/Analysis/PathDiagnostic.h"
#include "clang/Analysis/LocalCheckers.h"
#include "clang/Analysis/PathDiagnostic.h"
#include "clang/Analysis/PathSensitive/BugReporter.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/ImmutableMap.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/Compiler.h"
#include <ostream>
#include <sstream>
using namespace clang;
using llvm::CStrInCStrNoCase;
//===----------------------------------------------------------------------===//
// Utility functions.
//===----------------------------------------------------------------------===//
static inline Selector GetNullarySelector(const char* name, ASTContext& Ctx) {
IdentifierInfo* II = &Ctx.Idents.get(name);
return Ctx.Selectors.getSelector(0, &II);
}
static inline Selector GetUnarySelector(const char* name, ASTContext& Ctx) {
IdentifierInfo* II = &Ctx.Idents.get(name);
return Ctx.Selectors.getSelector(1, &II);
}
static bool isCFRefType(QualType T) {
if (!T->isPointerType())
return false;
// Check the typedef for the name "CF" and the substring "Ref".
TypedefType* TD = dyn_cast<TypedefType>(T.getTypePtr());
if (!TD)
return false;
const char* TDName = TD->getDecl()->getIdentifier()->getName();
assert (TDName);
if (TDName[0] != 'C' || TDName[1] != 'F')
return false;
if (strstr(TDName, "Ref") == 0)
return false;
return true;
}
static bool isNSType(QualType T) {
if (!T->isPointerType())
return false;
ObjCInterfaceType* OT = dyn_cast<ObjCInterfaceType>(T.getTypePtr());
if (!OT)
return false;
const char* ClsName = OT->getDecl()->getIdentifier()->getName();
assert (ClsName);
if (ClsName[0] != 'N' || ClsName[1] != 'S')
return false;
return true;
}
//===----------------------------------------------------------------------===//
// Symbolic Evaluation of Reference Counting Logic
//===----------------------------------------------------------------------===//
namespace {
enum ArgEffect { IncRef, DecRef, DoNothing, StopTracking };
typedef std::vector<std::pair<unsigned,ArgEffect> > ArgEffects;
}
namespace llvm {
template <> struct FoldingSetTrait<ArgEffects> {
static void Profile(const ArgEffects& X, FoldingSetNodeID& ID) {
for (ArgEffects::const_iterator I = X.begin(), E = X.end(); I!= E; ++I) {
ID.AddInteger(I->first);
ID.AddInteger((unsigned) I->second);
}
}
};
} // end llvm namespace
namespace {
class RetEffect {
public:
enum Kind { NoRet = 0x0, Alias = 0x1, OwnedSymbol = 0x2,
NotOwnedSymbol = 0x3, ReceiverAlias=0x4 };
private:
unsigned Data;
RetEffect(Kind k, unsigned D) { Data = (D << 3) | (unsigned) k; }
public:
Kind getKind() const { return (Kind) (Data & 0x7); }
unsigned getValue() const {
assert(getKind() == Alias);
return Data >> 3;
}
static RetEffect MakeAlias(unsigned Idx) { return RetEffect(Alias, Idx); }
static RetEffect MakeReceiverAlias() { return RetEffect(ReceiverAlias, 0); }
static RetEffect MakeOwned() { return RetEffect(OwnedSymbol, 0); }
static RetEffect MakeNotOwned() { return RetEffect(NotOwnedSymbol, 0); }
static RetEffect MakeNoRet() { return RetEffect(NoRet, 0); }
operator Kind() const { return getKind(); }
void Profile(llvm::FoldingSetNodeID& ID) const { ID.AddInteger(Data); }
};
class RetainSummary : public llvm::FoldingSetNode {
/// 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;
ArgEffect Receiver;
RetEffect Ret;
public:
RetainSummary(ArgEffects* A, RetEffect R, ArgEffect defaultEff,
ArgEffect ReceiverEff)
: Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R) {}
ArgEffect getArg(unsigned idx) const {
if (!Args)
return DefaultArgEffect;
// If Args is present, it is likely to contain only 1 element.
// Just do a linear search. Do it from the back because functions with
// large numbers of arguments will be tail heavy with respect to which
// argument they actually modify with respect to the reference count.
for (ArgEffects::reverse_iterator I=Args->rbegin(), E=Args->rend();
I!=E; ++I) {
if (idx > I->first)
return DefaultArgEffect;
if (idx == I->first)
return I->second;
}
return DefaultArgEffect;
}
RetEffect getRetEffect() const {
return Ret;
}
ArgEffect getReceiverEffect() const {
return Receiver;
}
typedef ArgEffects::const_iterator arg_iterator;
arg_iterator begin_args() const { return Args->begin(); }
arg_iterator end_args() const { return Args->end(); }
static void Profile(llvm::FoldingSetNodeID& ID, ArgEffects* A,
RetEffect RetEff, ArgEffect DefaultEff,
ArgEffect ReceiverEff) {
ID.AddPointer(A);
ID.Add(RetEff);
ID.AddInteger((unsigned) DefaultEff);
ID.AddInteger((unsigned) ReceiverEff);
}
void Profile(llvm::FoldingSetNodeID& ID) const {
Profile(ID, Args, Ret, DefaultArgEffect, Receiver);
}
};
class RetainSummaryManager {
//==-----------------------------------------------------------------==//
// Typedefs.
//==-----------------------------------------------------------------==//
typedef llvm::FoldingSet<llvm::FoldingSetNodeWrapper<ArgEffects> >
ArgEffectsSetTy;
typedef llvm::FoldingSet<RetainSummary>
SummarySetTy;
typedef llvm::DenseMap<FunctionDecl*, RetainSummary*>
FuncSummariesTy;
typedef llvm::DenseMap<Selector, RetainSummary*>
ObjCMethSummariesTy;
//==-----------------------------------------------------------------==//
// Data.
//==-----------------------------------------------------------------==//
// Ctx - The ASTContext object for the analyzed ASTs.
ASTContext& Ctx;
// GCEnabled - Records whether or not the analyzed code runs in GC mode.
const bool GCEnabled;
// SummarySet - A FoldingSet of uniqued summaries.
SummarySetTy SummarySet;
// FuncSummaries - A map from FunctionDecls to summaries.
FuncSummariesTy FuncSummaries;
// ObjCInstMethSummaries - A map from selectors (for instance methods)
// to summaries.
ObjCMethSummariesTy ObjCInstMethSummaries;
// ObjCMethSummaries - A map from selectors to summaries.
ObjCMethSummariesTy ObjCMethSummaries;
// ArgEffectsSet - A FoldingSet of uniqued ArgEffects.
ArgEffectsSetTy ArgEffectsSet;
// BPAlloc - A BumpPtrAllocator used for allocating summaries, ArgEffects,
// and all other data used by the checker.
llvm::BumpPtrAllocator BPAlloc;
// ScratchArgs - A holding buffer for construct ArgEffects.
ArgEffects ScratchArgs;
RetainSummary* StopSummary;
//==-----------------------------------------------------------------==//
// Methods.
//==-----------------------------------------------------------------==//
// getArgEffects - Returns a persistent ArgEffects object based on the
// data in ScratchArgs.
ArgEffects* getArgEffects();
enum UnaryFuncKind { cfretain, cfrelease, cfmakecollectable };
RetainSummary* getUnarySummary(FunctionDecl* FD, UnaryFuncKind func);
RetainSummary* getNSSummary(FunctionDecl* FD, const char* FName);
RetainSummary* getCFSummary(FunctionDecl* FD, const char* FName);
RetainSummary* getCFSummaryCreateRule(FunctionDecl* FD);
RetainSummary* getCFSummaryGetRule(FunctionDecl* FD);
RetainSummary* getPersistentSummary(ArgEffects* AE, RetEffect RetEff,
ArgEffect ReceiverEff = DoNothing,
ArgEffect DefaultEff = DoNothing);
RetainSummary* getPersistentSummary(RetEffect RE,
ArgEffect ReceiverEff = DoNothing,
ArgEffect DefaultEff = DoNothing) {
return getPersistentSummary(getArgEffects(), RE, ReceiverEff, DefaultEff);
}
RetainSummary* getPersistentStopSummary() {
if (StopSummary)
return StopSummary;
StopSummary = getPersistentSummary(RetEffect::MakeNoRet(),
StopTracking, StopTracking);
return StopSummary;
}
RetainSummary* getInitMethodSummary(Selector S);
void InitializeInstMethSummaries();
void InitializeMethSummaries();
public:
RetainSummaryManager(ASTContext& ctx, bool gcenabled)
: Ctx(ctx), GCEnabled(gcenabled), StopSummary(0) {
InitializeInstMethSummaries();
InitializeMethSummaries();
}
~RetainSummaryManager();
RetainSummary* getSummary(FunctionDecl* FD, ASTContext& Ctx);
RetainSummary* getMethodSummary(ObjCMessageExpr* ME);
RetainSummary* getInstanceMethodSummary(IdentifierInfo* ClsName, Selector S);
bool isGCEnabled() const { return GCEnabled; }
};
} // end anonymous namespace
//===----------------------------------------------------------------------===//
// Implementation of checker data structures.
//===----------------------------------------------------------------------===//
RetainSummaryManager::~RetainSummaryManager() {
// FIXME: The ArgEffects could eventually be allocated from BPAlloc,
// mitigating the need to do explicit cleanup of the
// Argument-Effect summaries.
for (ArgEffectsSetTy::iterator I = ArgEffectsSet.begin(),
E = ArgEffectsSet.end(); I!=E; ++I)
I->getValue().~ArgEffects();
}
ArgEffects* RetainSummaryManager::getArgEffects() {
if (ScratchArgs.empty())
return NULL;
// Compute a profile for a non-empty ScratchArgs.
llvm::FoldingSetNodeID profile;
profile.Add(ScratchArgs);
void* InsertPos;
// Look up the uniqued copy, or create a new one.
llvm::FoldingSetNodeWrapper<ArgEffects>* E =
ArgEffectsSet.FindNodeOrInsertPos(profile, InsertPos);
if (E) {
ScratchArgs.clear();
return &E->getValue();
}
E = (llvm::FoldingSetNodeWrapper<ArgEffects>*)
BPAlloc.Allocate<llvm::FoldingSetNodeWrapper<ArgEffects> >();
new (E) llvm::FoldingSetNodeWrapper<ArgEffects>(ScratchArgs);
ArgEffectsSet.InsertNode(E, InsertPos);
ScratchArgs.clear();
return &E->getValue();
}
RetainSummary*
RetainSummaryManager::getPersistentSummary(ArgEffects* AE, RetEffect RetEff,
ArgEffect ReceiverEff,
ArgEffect DefaultEff) {
// Generate a profile for the summary.
llvm::FoldingSetNodeID profile;
RetainSummary::Profile(profile, AE, RetEff, DefaultEff, ReceiverEff);
// Look up the uniqued summary, or create one if it doesn't exist.
void* InsertPos;
RetainSummary* Summ = SummarySet.FindNodeOrInsertPos(profile, InsertPos);
if (Summ)
return Summ;
// Create the summary and return it.
Summ = (RetainSummary*) BPAlloc.Allocate<RetainSummary>();
new (Summ) RetainSummary(AE, RetEff, DefaultEff, ReceiverEff);
SummarySet.InsertNode(Summ, InsertPos);
return Summ;
}
//===----------------------------------------------------------------------===//
// Summary creation for functions (largely uses of Core Foundation).
//===----------------------------------------------------------------------===//
RetainSummary* RetainSummaryManager::getSummary(FunctionDecl* FD,
ASTContext& Ctx) {
SourceLocation Loc = FD->getLocation();
if (!Loc.isFileID())
return NULL;
// Look up a summary in our cache of FunctionDecls -> Summaries.
FuncSummariesTy::iterator I = FuncSummaries.find(FD);
if (I != FuncSummaries.end())
return I->second;
// No summary. Generate one.
const char* FName = FD->getIdentifier()->getName();
RetainSummary *S = 0;
FunctionType* FT = dyn_cast<FunctionType>(FD->getType());
if (FT && isCFRefType(FT->getResultType()))
S = getCFSummary(FD, FName);
else if (FName[0] == 'C' && FName[1] == 'F')
S = getCFSummary(FD, FName);
else if (FName[0] == 'N' && FName[1] == 'S')
S = getNSSummary(FD, FName);
FuncSummaries[FD] = S;
return S;
}
RetainSummary* RetainSummaryManager::getNSSummary(FunctionDecl* FD,
const char* FName) {
FName += 2;
if (strcmp(FName, "MakeCollectable") == 0)
return getUnarySummary(FD, cfmakecollectable);
return 0;
}
RetainSummary* RetainSummaryManager::getCFSummary(FunctionDecl* FD,
const char* FName) {
if (FName[0] == 'C' && FName[1] == 'F')
FName += 2;
if (strcmp(FName, "Retain") == 0)
return getUnarySummary(FD, cfretain);
if (strcmp(FName, "Release") == 0)
return getUnarySummary(FD, cfrelease);
if (strcmp(FName, "MakeCollectable") == 0)
return getUnarySummary(FD, cfmakecollectable);
if (strstr(FName, "Create") || strstr(FName, "Copy"))
return getCFSummaryCreateRule(FD);
if (strstr(FName, "Get"))
return getCFSummaryGetRule(FD);
return 0;
}
RetainSummary*
RetainSummaryManager::getUnarySummary(FunctionDecl* FD, UnaryFuncKind func) {
FunctionTypeProto* FT =
dyn_cast<FunctionTypeProto>(FD->getType().getTypePtr());
if (FT) {
if (FT->getNumArgs() != 1)
return 0;
TypedefType* ArgT = dyn_cast<TypedefType>(FT->getArgType(0).getTypePtr());
if (!ArgT)
return 0;
if (!ArgT->isPointerType())
return NULL;
}
assert (ScratchArgs.empty());
switch (func) {
case cfretain: {
ScratchArgs.push_back(std::make_pair(0, IncRef));
return getPersistentSummary(RetEffect::MakeAlias(0));
}
case cfrelease: {
ScratchArgs.push_back(std::make_pair(0, DecRef));
return getPersistentSummary(RetEffect::MakeNoRet());
}
case cfmakecollectable: {
if (GCEnabled)
ScratchArgs.push_back(std::make_pair(0, DecRef));
return getPersistentSummary(RetEffect::MakeAlias(0));
}
default:
assert (false && "Not a supported unary function.");
}
}
RetainSummary* RetainSummaryManager::getCFSummaryCreateRule(FunctionDecl* FD) {
FunctionType* FT =
dyn_cast<FunctionType>(FD->getType().getTypePtr());
if (FT && !isCFRefType(FT->getResultType()))
return 0;
// FIXME: Add special-cases for functions that retain/release. For now
// just handle the default case.
assert (ScratchArgs.empty());
return getPersistentSummary(RetEffect::MakeOwned());
}
RetainSummary* RetainSummaryManager::getCFSummaryGetRule(FunctionDecl* FD) {
FunctionType* FT =
dyn_cast<FunctionType>(FD->getType().getTypePtr());
if (FT) {
QualType RetTy = FT->getResultType();
// FIXME: For now we assume that all pointer types returned are referenced
// counted. Since this is the "Get" rule, we assume non-ownership, which
// works fine for things that are not reference counted. We do this because
// some generic data structures return "void*". We need something better
// in the future.
if (!isCFRefType(RetTy) && !RetTy->isPointerType())
return 0;
}
// FIXME: Add special-cases for functions that retain/release. For now
// just handle the default case.
assert (ScratchArgs.empty());
return getPersistentSummary(RetEffect::MakeNotOwned());
}
//===----------------------------------------------------------------------===//
// Summary creation for Selectors.
//===----------------------------------------------------------------------===//
RetainSummary*
RetainSummaryManager::getInitMethodSummary(Selector S) {
assert(ScratchArgs.empty());
RetainSummary* Summ =
getPersistentSummary(RetEffect::MakeReceiverAlias());
ObjCMethSummaries[S] = Summ;
return Summ;
}
RetainSummary*
RetainSummaryManager::getMethodSummary(ObjCMessageExpr* ME) {
Selector S = ME->getSelector();
// Look up a summary in our cache of Selectors -> Summaries.
ObjCMethSummariesTy::iterator I = ObjCMethSummaries.find(S);
if (I != ObjCMethSummaries.end())
return I->second;
#if 0
// Only generate real summaries for methods involving
// NSxxxx objects.
if (!isNSType(ME->getReceiver()->getType())) {
RetainSummary* Summ = getPersistentStopSummary();
ObjCMethSummaries[S] = Summ;
return Summ;
}
#endif
if (!ME->getType()->isPointerType())
return 0;
// "initXXX": pass-through for receiver.
const char* s = S.getIdentifierInfoForSlot(0)->getName();
assert (ScratchArgs.empty());
if (strncmp(s, "init", 4) == 0)
return getInitMethodSummary(S);
// "copyXXX", "createXXX", "newXXX": allocators.
if (!isNSType(ME->getReceiver()->getType()))
return 0;
if (CStrInCStrNoCase(s, "create") || CStrInCStrNoCase(s, "copy") ||
CStrInCStrNoCase(s, "new")) {
RetEffect E = isGCEnabled() ? RetEffect::MakeNoRet()
: RetEffect::MakeOwned();
RetainSummary* Summ = getPersistentSummary(E);
ObjCMethSummaries[S] = Summ;
return Summ;
}
return 0;
}
RetainSummary*
RetainSummaryManager::getInstanceMethodSummary(IdentifierInfo* ClsName,
Selector S) {
// Look up a summary in our cache of Selectors -> Summaries.
ObjCMethSummariesTy::iterator I = ObjCInstMethSummaries.find(S);
if (I != ObjCInstMethSummaries.end())
return I->second;
return 0;
#if 0
return 0;
// Don't track anything if using GC.
if (isGCEnabled())
return 0;
// Inspect the class name and selecrtor to determine if this method
// creates new objects.
const char* cls = ClsName->getName();
if (cls[0] == 'N' && cls[1] == 'S') // Ignore preceding "NS" (if present).
cls += 2;
// Heuristic: XXXwithYYY, where XXX is the class name with the "NS"
// stripped off is usually an allocation.
const char* s = S.getIdentifierInfoForSlot(0)->getName();
if (cls[0] == '\0' || s[0] == '\0' || tolower(cls[0]) != s[0])
return 0;
// Now look at the rest of the characters.
++cls; ++s;
unsigned len = strlen(cls);
// If the prefix doesn't match, don't generate a special summary.
if (strncmp(cls, s, len) != 0)
return 0;
// Look at the text after the prefix.
s += len;
if (!(s[0] == '\0' || strncmp(s, "With", 4) == 0))
return 0;
// Generate and return the summary.
assert (ScratchArgs.empty());
RetainSummary* Summ = getPersistentSummary(RetEffect::MakeOwned());
ObjCInstMethSummaries[S] = Summ;
return Summ;
#endif
}
void RetainSummaryManager::InitializeInstMethSummaries() {
assert (ScratchArgs.empty());
RetEffect E = isGCEnabled() ? RetEffect::MakeNoRet() : RetEffect::MakeOwned();
RetainSummary* Summ = getPersistentSummary(E);
// Create the "alloc" selector.
ObjCInstMethSummaries[ GetNullarySelector("alloc", Ctx) ] = Summ;
// Create the "new" selector.
ObjCInstMethSummaries[ GetNullarySelector("new", Ctx) ] = Summ;
// Create the "allocWithZone:" selector.
ObjCInstMethSummaries[ GetUnarySelector("allocWithZone", Ctx) ] = Summ;
}
void RetainSummaryManager::InitializeMethSummaries() {
assert (ScratchArgs.empty());
// Create the "init" selector. It just acts as a pass-through for the
// receiver.
RetainSummary* Summ = getPersistentSummary(RetEffect::MakeReceiverAlias());
ObjCMethSummaries[ GetNullarySelector("init", Ctx) ] = Summ;
// The next methods are allocators.
RetEffect E = isGCEnabled() ? RetEffect::MakeNoRet() : RetEffect::MakeOwned();
Summ = getPersistentSummary(E);
// Create the "copy" selector.
ObjCMethSummaries[ GetNullarySelector("copy", Ctx) ] = Summ;
// Create the "mutableCopy" selector.
ObjCMethSummaries[ GetNullarySelector("mutableCopy", Ctx) ] = Summ;
// Create the "retain" selector.
E = RetEffect::MakeReceiverAlias();
Summ = getPersistentSummary(E, isGCEnabled() ? DoNothing : IncRef);
ObjCMethSummaries[ GetNullarySelector("retain", Ctx) ] = Summ;
// Create the "release" selector.
Summ = getPersistentSummary(E, isGCEnabled() ? DoNothing : DecRef);
ObjCMethSummaries[ GetNullarySelector("release", Ctx) ] = Summ;
// Create the "drain" selector.
Summ = getPersistentSummary(E, isGCEnabled() ? DoNothing : DecRef);
ObjCMethSummaries[ GetNullarySelector("drain", Ctx) ] = Summ;
// Create the "autorelease" selector.
Summ = getPersistentSummary(E, isGCEnabled() ? DoNothing : StopTracking);
ObjCMethSummaries[ GetNullarySelector("autorelease", Ctx) ] = Summ;
}
//===----------------------------------------------------------------------===//
// Reference-counting logic (typestate + counts).
//===----------------------------------------------------------------------===//
namespace {
class VISIBILITY_HIDDEN 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.
ErrorUseAfterRelease, // Object used after released.
ErrorReleaseNotOwned, // Release of an object that was not owned.
ErrorLeak // A memory leak due to excessive reference counts.
};
private:
Kind kind;
unsigned Cnt;
RefVal(Kind k, unsigned cnt) : kind(k), Cnt(cnt) {}
RefVal(Kind k) : kind(k), Cnt(0) {}
public:
Kind getKind() const { return kind; }
unsigned getCount() const { return Cnt; }
// Useful predicates.
static bool isError(Kind k) { return k >= ErrorUseAfterRelease; }
static bool isLeak(Kind k) { return k == ErrorLeak; }
bool isOwned() const {
return getKind() == Owned;
}
bool isNotOwned() const {
return getKind() == NotOwned;
}
bool isReturnedOwned() const {
return getKind() == ReturnedOwned;
}
bool isReturnedNotOwned() const {
return getKind() == ReturnedNotOwned;
}
bool isNonLeakError() const {
Kind k = getKind();
return isError(k) && !isLeak(k);
}
// State creation: normal state.
static RefVal makeOwned(unsigned Count = 0) {
return RefVal(Owned, Count);
}
static RefVal makeNotOwned(unsigned Count = 0) {
return RefVal(NotOwned, Count);
}
static RefVal makeReturnedOwned(unsigned Count) {
return RefVal(ReturnedOwned, Count);
}
static RefVal makeReturnedNotOwned() {
return RefVal(ReturnedNotOwned);
}
// State creation: errors.
static RefVal makeLeak(unsigned Count) { return RefVal(ErrorLeak, Count); }
static RefVal makeReleased() { return RefVal(Released); }
static RefVal makeUseAfterRelease() { return RefVal(ErrorUseAfterRelease); }
static RefVal makeReleaseNotOwned() { return RefVal(ErrorReleaseNotOwned); }
// Comparison, profiling, and pretty-printing.
bool operator==(const RefVal& X) const {
return kind == X.kind && Cnt == X.Cnt;
}
void Profile(llvm::FoldingSetNodeID& ID) const {
ID.AddInteger((unsigned) kind);
ID.AddInteger(Cnt);
}
void print(std::ostream& Out) const;
};
void RefVal::print(std::ostream& Out) const {
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 ErrorLeak:
Out << "Leaked";
break;
case ErrorUseAfterRelease:
Out << "Use-After-Release [ERROR]";
break;
case ErrorReleaseNotOwned:
Out << "Release of Not-Owned [ERROR]";
break;
}
}
static inline unsigned GetCount(RefVal V) {
switch (V.getKind()) {
default:
return V.getCount();
case RefVal::Owned:
return V.getCount()+1;
}
}
//===----------------------------------------------------------------------===//
// Transfer functions.
//===----------------------------------------------------------------------===//
class VISIBILITY_HIDDEN CFRefCount : public GRSimpleVals {
public:
// Type definitions.
typedef llvm::ImmutableMap<SymbolID, RefVal> RefBindings;
typedef RefBindings::Factory RefBFactoryTy;
typedef llvm::DenseMap<GRExprEngine::NodeTy*,std::pair<Expr*, SymbolID> >
ReleasesNotOwnedTy;
typedef ReleasesNotOwnedTy UseAfterReleasesTy;
typedef llvm::DenseMap<GRExprEngine::NodeTy*, std::vector<SymbolID>*>
LeaksTy;
class BindingsPrinter : public ValueState::CheckerStatePrinter {
public:
virtual void PrintCheckerState(std::ostream& Out, void* State,
const char* nl, const char* sep);
};
private:
// Instance variables.
RetainSummaryManager Summaries;
const bool EmitStandardWarnings;
const LangOptions& LOpts;
RefBFactoryTy RefBFactory;
UseAfterReleasesTy UseAfterReleases;
ReleasesNotOwnedTy ReleasesNotOwned;
LeaksTy Leaks;
BindingsPrinter Printer;
Selector RetainSelector;
Selector ReleaseSelector;
Selector AutoreleaseSelector;
public:
static RefBindings GetRefBindings(ValueState& StImpl) {
return RefBindings((RefBindings::TreeTy*) StImpl.CheckerState);
}
private:
static void SetRefBindings(ValueState& StImpl, RefBindings B) {
StImpl.CheckerState = B.getRoot();
}
RefBindings Remove(RefBindings B, SymbolID sym) {
return RefBFactory.Remove(B, sym);
}
RefBindings Update(RefBindings B, SymbolID sym, RefVal V, ArgEffect E,
RefVal::Kind& hasErr);
void ProcessNonLeakError(ExplodedNodeSet<ValueState>& Dst,
GRStmtNodeBuilder<ValueState>& Builder,
Expr* NodeExpr, Expr* ErrorExpr,
ExplodedNode<ValueState>* Pred,
ValueState* St,
RefVal::Kind hasErr, SymbolID Sym);
ValueState* HandleSymbolDeath(ValueStateManager& VMgr, ValueState* St,
SymbolID sid, RefVal V, bool& hasLeak);
ValueState* NukeBinding(ValueStateManager& VMgr, ValueState* St,
SymbolID sid);
public:
CFRefCount(ASTContext& Ctx, bool gcenabled, bool StandardWarnings,
const LangOptions& lopts)
: Summaries(Ctx, gcenabled),
EmitStandardWarnings(StandardWarnings),
LOpts(lopts),
RetainSelector(GetNullarySelector("retain", Ctx)),
ReleaseSelector(GetNullarySelector("release", Ctx)),
AutoreleaseSelector(GetNullarySelector("autorelease", Ctx)) {}
virtual ~CFRefCount() {
for (LeaksTy::iterator I = Leaks.begin(), E = Leaks.end(); I!=E; ++I)
delete I->second;
}
virtual void RegisterChecks(GRExprEngine& Eng);
virtual ValueState::CheckerStatePrinter* getCheckerStatePrinter() {
return &Printer;
}
bool isGCEnabled() const { return Summaries.isGCEnabled(); }
const LangOptions& getLangOptions() const { return LOpts; }
// Calls.
void EvalSummary(ExplodedNodeSet<ValueState>& Dst,
GRExprEngine& Eng,
GRStmtNodeBuilder<ValueState>& Builder,
Expr* Ex,
Expr* Receiver,
RetainSummary* Summ,
Expr** arg_beg, Expr** arg_end,
ExplodedNode<ValueState>* Pred);
virtual void EvalCall(ExplodedNodeSet<ValueState>& Dst,
GRExprEngine& Eng,
GRStmtNodeBuilder<ValueState>& Builder,
CallExpr* CE, RVal L,
ExplodedNode<ValueState>* Pred);
virtual void EvalObjCMessageExpr(ExplodedNodeSet<ValueState>& Dst,
GRExprEngine& Engine,
GRStmtNodeBuilder<ValueState>& Builder,
ObjCMessageExpr* ME,
ExplodedNode<ValueState>* Pred);
bool EvalObjCMessageExprAux(ExplodedNodeSet<ValueState>& Dst,
GRExprEngine& Engine,
GRStmtNodeBuilder<ValueState>& Builder,
ObjCMessageExpr* ME,
ExplodedNode<ValueState>* Pred);
// Stores.
virtual void EvalStore(ExplodedNodeSet<ValueState>& Dst,
GRExprEngine& Engine,
GRStmtNodeBuilder<ValueState>& Builder,
Expr* E, ExplodedNode<ValueState>* Pred,
ValueState* St, RVal TargetLV, RVal Val);
// End-of-path.
virtual void EvalEndPath(GRExprEngine& Engine,
GREndPathNodeBuilder<ValueState>& Builder);
virtual void EvalDeadSymbols(ExplodedNodeSet<ValueState>& Dst,
GRExprEngine& Engine,
GRStmtNodeBuilder<ValueState>& Builder,
ExplodedNode<ValueState>* Pred,
Stmt* S,
ValueState* St,
const ValueStateManager::DeadSymbolsTy& Dead);
// Return statements.
virtual void EvalReturn(ExplodedNodeSet<ValueState>& Dst,
GRExprEngine& Engine,
GRStmtNodeBuilder<ValueState>& Builder,
ReturnStmt* S,
ExplodedNode<ValueState>* Pred);
// Assumptions.
virtual ValueState* EvalAssume(GRExprEngine& Engine, ValueState* St,
RVal Cond, bool Assumption, bool& isFeasible);
// Error iterators.
typedef UseAfterReleasesTy::iterator use_after_iterator;
typedef ReleasesNotOwnedTy::iterator bad_release_iterator;
typedef LeaksTy::iterator leaks_iterator;
use_after_iterator use_after_begin() { return UseAfterReleases.begin(); }
use_after_iterator use_after_end() { return UseAfterReleases.end(); }
bad_release_iterator bad_release_begin() { return ReleasesNotOwned.begin(); }
bad_release_iterator bad_release_end() { return ReleasesNotOwned.end(); }
leaks_iterator leaks_begin() { return Leaks.begin(); }
leaks_iterator leaks_end() { return Leaks.end(); }
};
} // end anonymous namespace
void CFRefCount::BindingsPrinter::PrintCheckerState(std::ostream& Out,
void* State, const char* nl,
const char* sep) {
RefBindings B((RefBindings::TreeTy*) State);
if (State)
Out << sep << nl;
for (RefBindings::iterator I=B.begin(), E=B.end(); I!=E; ++I) {
Out << (*I).first << " : ";
(*I).second.print(Out);
Out << nl;
}
}
static inline ArgEffect GetArgE(RetainSummary* Summ, unsigned idx) {
return Summ ? Summ->getArg(idx) : DoNothing;
}
static inline RetEffect GetRetEffect(RetainSummary* Summ) {
return Summ ? Summ->getRetEffect() : RetEffect::MakeNoRet();
}
static inline ArgEffect GetReceiverE(RetainSummary* Summ) {
return Summ ? Summ->getReceiverEffect() : DoNothing;
}
void CFRefCount::ProcessNonLeakError(ExplodedNodeSet<ValueState>& Dst,
GRStmtNodeBuilder<ValueState>& Builder,
Expr* NodeExpr, Expr* ErrorExpr,
ExplodedNode<ValueState>* Pred,
ValueState* St,
RefVal::Kind hasErr, SymbolID Sym) {
Builder.BuildSinks = true;
GRExprEngine::NodeTy* N = Builder.MakeNode(Dst, NodeExpr, Pred, St);
if (!N) return;
switch (hasErr) {
default: assert(false);
case RefVal::ErrorUseAfterRelease:
UseAfterReleases[N] = std::make_pair(ErrorExpr, Sym);
break;
case RefVal::ErrorReleaseNotOwned:
ReleasesNotOwned[N] = std::make_pair(ErrorExpr, Sym);
break;
}
}
void CFRefCount::EvalSummary(ExplodedNodeSet<ValueState>& Dst,
GRExprEngine& Eng,
GRStmtNodeBuilder<ValueState>& Builder,
Expr* Ex,
Expr* Receiver,
RetainSummary* Summ,
Expr** arg_beg, Expr** arg_end,
ExplodedNode<ValueState>* Pred) {
// Get the state.
ValueStateManager& StateMgr = Eng.getStateManager();
ValueState* St = Builder.GetState(Pred);
// Evaluate the effect of the arguments.
ValueState StVals = *St;
RefVal::Kind hasErr = (RefVal::Kind) 0;
unsigned idx = 0;
Expr* ErrorExpr = NULL;
SymbolID ErrorSym = 0;
for (Expr **I = arg_beg, **E = arg_end; I != E; ++I, ++idx) {
RVal V = StateMgr.GetRVal(St, *I);
if (isa<lval::SymbolVal>(V)) {
SymbolID Sym = cast<lval::SymbolVal>(V).getSymbol();
RefBindings B = GetRefBindings(StVals);
if (RefBindings::TreeTy* T = B.SlimFind(Sym)) {
B = Update(B, Sym, T->getValue().second, GetArgE(Summ, idx), hasErr);
SetRefBindings(StVals, B);
if (hasErr) {
ErrorExpr = *I;
ErrorSym = T->getValue().first;
break;
}
}
}
else if (isa<LVal>(V)) {
// Nuke all arguments passed by reference.
StateMgr.Unbind(StVals, cast<LVal>(V));
}
else if (isa<nonlval::LValAsInteger>(V))
StateMgr.Unbind(StVals, cast<nonlval::LValAsInteger>(V).getLVal());
}
// Evaluate the effect on the message receiver.
if (!ErrorExpr && Receiver) {
RVal V = StateMgr.GetRVal(St, Receiver);
if (isa<lval::SymbolVal>(V)) {
SymbolID Sym = cast<lval::SymbolVal>(V).getSymbol();
RefBindings B = GetRefBindings(StVals);
if (RefBindings::TreeTy* T = B.SlimFind(Sym)) {
B = Update(B, Sym, T->getValue().second, GetReceiverE(Summ), hasErr);
SetRefBindings(StVals, B);
if (hasErr) {
ErrorExpr = Receiver;
ErrorSym = T->getValue().first;
}
}
}
}
// Get the persistent state.
St = StateMgr.getPersistentState(StVals);
// Process any errors.
if (hasErr) {
ProcessNonLeakError(Dst, Builder, Ex, ErrorExpr, Pred, St,
hasErr, ErrorSym);
return;
}
// Finally, consult the summary for the return value.
RetEffect RE = GetRetEffect(Summ);
switch (RE.getKind()) {
default:
assert (false && "Unhandled RetEffect."); break;
case RetEffect::NoRet:
// Make up a symbol for the return value (not reference counted).
// FIXME: This is basically copy-and-paste from GRSimpleVals. We
// should compose behavior, not copy it.
if (Ex->getType() != Eng.getContext().VoidTy) {
unsigned Count = Builder.getCurrentBlockCount();
SymbolID Sym = Eng.getSymbolManager().getConjuredSymbol(Ex, Count);
RVal X = Ex->getType()->isPointerType()
? cast<RVal>(lval::SymbolVal(Sym))
: cast<RVal>(nonlval::SymbolVal(Sym));
St = StateMgr.SetRVal(St, Ex, X, Eng.getCFG().isBlkExpr(Ex), false);
}
break;
case RetEffect::Alias: {
unsigned idx = RE.getValue();
assert ((arg_end - arg_beg) >= 0);
assert (idx < (unsigned) (arg_end - arg_beg));
RVal V = StateMgr.GetRVal(St, arg_beg[idx]);
St = StateMgr.SetRVal(St, Ex, V, Eng.getCFG().isBlkExpr(Ex), false);
break;
}
case RetEffect::ReceiverAlias: {
assert (Receiver);
RVal V = StateMgr.GetRVal(St, Receiver);
St = StateMgr.SetRVal(St, Ex, V, Eng.getCFG().isBlkExpr(Ex), false);
break;
}
case RetEffect::OwnedSymbol: {
unsigned Count = Builder.getCurrentBlockCount();
SymbolID Sym = Eng.getSymbolManager().getConjuredSymbol(Ex, Count);
ValueState StImpl = *St;
RefBindings B = GetRefBindings(StImpl);
SetRefBindings(StImpl, RefBFactory.Add(B, Sym, RefVal::makeOwned()));
St = StateMgr.SetRVal(StateMgr.getPersistentState(StImpl),
Ex, lval::SymbolVal(Sym),
Eng.getCFG().isBlkExpr(Ex), false);
break;
}
case RetEffect::NotOwnedSymbol: {
unsigned Count = Builder.getCurrentBlockCount();
SymbolID Sym = Eng.getSymbolManager().getConjuredSymbol(Ex, Count);
ValueState StImpl = *St;
RefBindings B = GetRefBindings(StImpl);
SetRefBindings(StImpl, RefBFactory.Add(B, Sym, RefVal::makeNotOwned()));
St = StateMgr.SetRVal(StateMgr.getPersistentState(StImpl),
Ex, lval::SymbolVal(Sym),
Eng.getCFG().isBlkExpr(Ex), false);
break;
}
}
Builder.MakeNode(Dst, Ex, Pred, St);
}
void CFRefCount::EvalCall(ExplodedNodeSet<ValueState>& Dst,
GRExprEngine& Eng,
GRStmtNodeBuilder<ValueState>& Builder,
CallExpr* CE, RVal L,
ExplodedNode<ValueState>* Pred) {
RetainSummary* Summ = NULL;
// Get the summary.
if (isa<lval::FuncVal>(L)) {
lval::FuncVal FV = cast<lval::FuncVal>(L);
FunctionDecl* FD = FV.getDecl();
Summ = Summaries.getSummary(FD, Eng.getContext());
}
EvalSummary(Dst, Eng, Builder, CE, 0, Summ,
CE->arg_begin(), CE->arg_end(), Pred);
}
void CFRefCount::EvalObjCMessageExpr(ExplodedNodeSet<ValueState>& Dst,
GRExprEngine& Eng,
GRStmtNodeBuilder<ValueState>& Builder,
ObjCMessageExpr* ME,
ExplodedNode<ValueState>* Pred) {
RetainSummary* Summ;
if (ME->getReceiver())
Summ = Summaries.getMethodSummary(ME);
else
Summ = Summaries.getInstanceMethodSummary(ME->getClassName(),
ME->getSelector());
EvalSummary(Dst, Eng, Builder, ME, ME->getReceiver(), Summ,
ME->arg_begin(), ME->arg_end(), Pred);
}
// Stores.
void CFRefCount::EvalStore(ExplodedNodeSet<ValueState>& Dst,
GRExprEngine& Eng,
GRStmtNodeBuilder<ValueState>& Builder,
Expr* E, ExplodedNode<ValueState>* Pred,
ValueState* St, RVal TargetLV, RVal Val) {
// Check if we have a binding for "Val" and if we are storing it to something
// we don't understand or otherwise the value "escapes" the function.
if (!isa<lval::SymbolVal>(Val))
return;
// Are we storing to something that causes the value to "escape"?
bool escapes = false;
if (!isa<lval::DeclVal>(TargetLV))
escapes = true;
else
escapes = cast<lval::DeclVal>(TargetLV).getDecl()->hasGlobalStorage();
if (!escapes)
return;
SymbolID Sym = cast<lval::SymbolVal>(Val).getSymbol();
RefBindings B = GetRefBindings(*St);
RefBindings::TreeTy* T = B.SlimFind(Sym);
if (!T)
return;
// Nuke the binding.
St = NukeBinding(Eng.getStateManager(), St, Sym);
// Hand of the remaining logic to the parent implementation.
GRSimpleVals::EvalStore(Dst, Eng, Builder, E, Pred, St, TargetLV, Val);
}
ValueState* CFRefCount::NukeBinding(ValueStateManager& VMgr, ValueState* St,
SymbolID sid) {
ValueState StImpl = *St;
RefBindings B = GetRefBindings(StImpl);
StImpl.CheckerState = RefBFactory.Remove(B, sid).getRoot();
return VMgr.getPersistentState(StImpl);
}
// End-of-path.
ValueState* CFRefCount::HandleSymbolDeath(ValueStateManager& VMgr,
ValueState* St, SymbolID sid,
RefVal V, bool& hasLeak) {
hasLeak = V.isOwned() ||
((V.isNotOwned() || V.isReturnedOwned()) && V.getCount() > 0);
if (!hasLeak)
return NukeBinding(VMgr, St, sid);
RefBindings B = GetRefBindings(*St);
ValueState StImpl = *St;
StImpl.CheckerState =
RefBFactory.Add(B, sid, RefVal::makeLeak(GetCount(V))).getRoot();
return VMgr.getPersistentState(StImpl);
}
void CFRefCount::EvalEndPath(GRExprEngine& Eng,
GREndPathNodeBuilder<ValueState>& Builder) {
ValueState* St = Builder.getState();
RefBindings B = GetRefBindings(*St);
llvm::SmallVector<SymbolID, 10> Leaked;
for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) {
bool hasLeak = false;
St = HandleSymbolDeath(Eng.getStateManager(), St,
(*I).first, (*I).second, hasLeak);
if (hasLeak) Leaked.push_back((*I).first);
}
if (Leaked.empty())
return;
ExplodedNode<ValueState>* N = Builder.MakeNode(St);
if (!N)
return;
std::vector<SymbolID>*& LeaksAtNode = Leaks[N];
assert (!LeaksAtNode);
LeaksAtNode = new std::vector<SymbolID>();
for (llvm::SmallVector<SymbolID, 10>::iterator I=Leaked.begin(),
E = Leaked.end(); I != E; ++I)
(*LeaksAtNode).push_back(*I);
}
// Dead symbols.
void CFRefCount::EvalDeadSymbols(ExplodedNodeSet<ValueState>& Dst,
GRExprEngine& Eng,
GRStmtNodeBuilder<ValueState>& Builder,
ExplodedNode<ValueState>* Pred,
Stmt* S,
ValueState* St,
const ValueStateManager::DeadSymbolsTy& Dead) {
// FIXME: a lot of copy-and-paste from EvalEndPath. Refactor.
RefBindings B = GetRefBindings(*St);
llvm::SmallVector<SymbolID, 10> Leaked;
for (ValueStateManager::DeadSymbolsTy::const_iterator
I=Dead.begin(), E=Dead.end(); I!=E; ++I) {
RefBindings::TreeTy* T = B.SlimFind(*I);
if (!T)
continue;
bool hasLeak = false;
St = HandleSymbolDeath(Eng.getStateManager(), St,
*I, T->getValue().second, hasLeak);
if (hasLeak) Leaked.push_back(*I);
}
if (Leaked.empty())
return;
ExplodedNode<ValueState>* N = Builder.MakeNode(Dst, S, Pred, St);
if (!N)
return;
std::vector<SymbolID>*& LeaksAtNode = Leaks[N];
assert (!LeaksAtNode);
LeaksAtNode = new std::vector<SymbolID>();
for (llvm::SmallVector<SymbolID, 10>::iterator I=Leaked.begin(),
E = Leaked.end(); I != E; ++I)
(*LeaksAtNode).push_back(*I);
}
// Return statements.
void CFRefCount::EvalReturn(ExplodedNodeSet<ValueState>& Dst,
GRExprEngine& Eng,
GRStmtNodeBuilder<ValueState>& Builder,
ReturnStmt* S,
ExplodedNode<ValueState>* Pred) {
Expr* RetE = S->getRetValue();
if (!RetE) return;
ValueStateManager& StateMgr = Eng.getStateManager();
ValueState* St = Builder.GetState(Pred);
RVal V = StateMgr.GetRVal(St, RetE);
if (!isa<lval::SymbolVal>(V))
return;
// Get the reference count binding (if any).
SymbolID Sym = cast<lval::SymbolVal>(V).getSymbol();
RefBindings B = GetRefBindings(*St);
RefBindings::TreeTy* T = B.SlimFind(Sym);
if (!T)
return;
// Change the reference count.
RefVal X = T->getValue().second;
switch (X.getKind()) {
case RefVal::Owned: {
unsigned cnt = X.getCount();
X = RefVal::makeReturnedOwned(cnt);
break;
}
case RefVal::NotOwned: {
unsigned cnt = X.getCount();
X = cnt ? RefVal::makeReturnedOwned(cnt - 1)
: RefVal::makeReturnedNotOwned();
break;
}
default:
return;
}
// Update the binding.
ValueState StImpl = *St;
StImpl.CheckerState = RefBFactory.Add(B, Sym, X).getRoot();
Builder.MakeNode(Dst, S, Pred, StateMgr.getPersistentState(StImpl));
}
// Assumptions.
ValueState* CFRefCount::EvalAssume(GRExprEngine& Eng, ValueState* St,
RVal Cond, bool Assumption,
bool& isFeasible) {
// 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 = GetRefBindings(*St);
if (B.isEmpty())
return St;
bool changed = false;
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 (St->getSymVal(I.getKey())) {
changed = true;
B = RefBFactory.Remove(B, I.getKey());
}
}
if (!changed)
return St;
ValueState StImpl = *St;
StImpl.CheckerState = B.getRoot();
return Eng.getStateManager().getPersistentState(StImpl);
}
CFRefCount::RefBindings CFRefCount::Update(RefBindings B, SymbolID sym,
RefVal V, ArgEffect E,
RefVal::Kind& hasErr) {
// FIXME: This dispatch can potentially be sped up by unifiying it into
// a single switch statement. Opt for simplicity for now.
switch (E) {
default:
assert (false && "Unhandled CFRef transition.");
case DoNothing:
if (!isGCEnabled() && V.getKind() == RefVal::Released) {
V = RefVal::makeUseAfterRelease();
hasErr = V.getKind();
break;
}
return B;
case StopTracking:
return RefBFactory.Remove(B, sym);
case IncRef:
switch (V.getKind()) {
default:
assert(false);
case RefVal::Owned:
V = RefVal::makeOwned(V.getCount()+1);
break;
case RefVal::NotOwned:
V = RefVal::makeNotOwned(V.getCount()+1);
break;
case RefVal::Released:
if (isGCEnabled())
V = RefVal::makeOwned();
else {
V = RefVal::makeUseAfterRelease();
hasErr = V.getKind();
}
break;
}
break;
case DecRef:
switch (V.getKind()) {
default:
assert (false);
case RefVal::Owned: {
unsigned Count = V.getCount();
V = Count > 0 ? RefVal::makeOwned(Count - 1) : RefVal::makeReleased();
break;
}
case RefVal::NotOwned: {
unsigned Count = V.getCount();
if (Count > 0)
V = RefVal::makeNotOwned(Count - 1);
else {
V = RefVal::makeReleaseNotOwned();
hasErr = V.getKind();
}
break;
}
case RefVal::Released:
V = RefVal::makeUseAfterRelease();
hasErr = V.getKind();
break;
}
break;
}
return RefBFactory.Add(B, sym, V);
}
//===----------------------------------------------------------------------===//
// Error reporting.
//===----------------------------------------------------------------------===//
namespace {
//===-------------===//
// Bug Descriptions. //
//===-------------===//
class VISIBILITY_HIDDEN CFRefBug : public BugTypeCacheLocation {
protected:
CFRefCount& TF;
public:
CFRefBug(CFRefCount& tf) : TF(tf) {}
CFRefCount& getTF() { return TF; }
const CFRefCount& getTF() const { return TF; }
virtual bool isLeak() const { return false; }
};
class VISIBILITY_HIDDEN UseAfterRelease : public CFRefBug {
public:
UseAfterRelease(CFRefCount& tf) : CFRefBug(tf) {}
virtual const char* getName() const {
return "Use-After-Release";
}
virtual const char* getDescription() const {
return "Reference-counted object is used"
" after it is released.";
}
virtual void EmitWarnings(BugReporter& BR);
};
class VISIBILITY_HIDDEN BadRelease : public CFRefBug {
public:
BadRelease(CFRefCount& tf) : CFRefBug(tf) {}
virtual const char* getName() const {
return "Bad Release";
}
virtual const char* getDescription() const {
return "Incorrect decrement of the reference count of a "
"CoreFoundation object: "
"The object is not owned at this point by the caller.";
}
virtual void EmitWarnings(BugReporter& BR);
};
class VISIBILITY_HIDDEN Leak : public CFRefBug {
public:
Leak(CFRefCount& tf) : CFRefBug(tf) {}
virtual const char* getName() const {
if (getTF().isGCEnabled())
return "Memory Leak (GC)";
if (getTF().getLangOptions().getGCMode() == LangOptions::HybridGC)
return "Memory Leak (Hybrid MM, non-GC)";
assert (getTF().getLangOptions().getGCMode() == LangOptions::NonGC);
return "Memory Leak";
}
virtual const char* getDescription() const {
return "Object leaked.";
}
virtual void EmitWarnings(BugReporter& BR);
virtual void GetErrorNodes(std::vector<ExplodedNode<ValueState>*>& Nodes);
virtual bool isLeak() const { return true; }
};
//===---------===//
// Bug Reports. //
//===---------===//
class VISIBILITY_HIDDEN CFRefReport : public RangedBugReport {
SymbolID Sym;
public:
CFRefReport(CFRefBug& D, ExplodedNode<ValueState> *n, SymbolID sym)
: RangedBugReport(D, n), Sym(sym) {}
virtual ~CFRefReport() {}
CFRefBug& getBugType() {
return (CFRefBug&) RangedBugReport::getBugType();
}
const CFRefBug& getBugType() const {
return (const CFRefBug&) RangedBugReport::getBugType();
}
virtual void getRanges(BugReporter& BR, const SourceRange*& beg,
const SourceRange*& end) {
if (!getBugType().isLeak())
RangedBugReport::getRanges(BR, beg, end);
else {
beg = 0;
end = 0;
}
}
virtual PathDiagnosticPiece* getEndPath(BugReporter& BR,
ExplodedNode<ValueState>* N);
virtual std::pair<const char**,const char**> getExtraDescriptiveText();
virtual PathDiagnosticPiece* VisitNode(ExplodedNode<ValueState>* N,
ExplodedNode<ValueState>* PrevN,
ExplodedGraph<ValueState>& G,
BugReporter& BR);
};
} // end anonymous namespace
void CFRefCount::RegisterChecks(GRExprEngine& Eng) {
if (EmitStandardWarnings) GRSimpleVals::RegisterChecks(Eng);
Eng.Register(new UseAfterRelease(*this));
Eng.Register(new BadRelease(*this));
Eng.Register(new Leak(*this));
}
static const char* Msgs[] = {
"Code is compiled in garbage collection only mode" // GC only
" (the bug occurs with garbage collection enabled).",
"Code is compiled without garbage collection.", // No GC.
"Code is compiled for use with and without garbage collection (GC)."
" The bug occurs with GC enabled.", // Hybrid, with GC.
"Code is compiled for use with and without garbage collection (GC)."
" The bug occurs in non-GC mode." // Hyrbird, without GC/
};
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);
}
}
PathDiagnosticPiece* CFRefReport::VisitNode(ExplodedNode<ValueState>* N,
ExplodedNode<ValueState>* PrevN,
ExplodedGraph<ValueState>& G,
BugReporter& BR) {
// Check if the type state has changed.
ValueState* PrevSt = PrevN->getState();
ValueState* CurrSt = N->getState();
CFRefCount::RefBindings PrevB = CFRefCount::GetRefBindings(*PrevSt);
CFRefCount::RefBindings CurrB = CFRefCount::GetRefBindings(*CurrSt);
CFRefCount::RefBindings::TreeTy* PrevT = PrevB.SlimFind(Sym);
CFRefCount::RefBindings::TreeTy* CurrT = CurrB.SlimFind(Sym);
if (!CurrT)
return NULL;
const char* Msg = NULL;
RefVal CurrV = CurrB.SlimFind(Sym)->getValue().second;
if (!PrevT) {
Stmt* S = cast<PostStmt>(N->getLocation()).getStmt();
if (CurrV.isOwned()) {
if (isa<CallExpr>(S))
Msg = "Function call returns an object with a +1 retain count"
" (owning reference).";
else {
assert (isa<ObjCMessageExpr>(S));
Msg = "Method returns an object with a +1 retain count"
" (owning reference).";
}
}
else {
assert (CurrV.isNotOwned());
if (isa<CallExpr>(S))
Msg = "Function call returns an object with a +0 retain count"
" (non-owning reference).";
else {
assert (isa<ObjCMessageExpr>(S));
Msg = "Method returns an object with a +0 retain count"
" (non-owning reference).";
}
}
FullSourceLoc Pos(S->getLocStart(), BR.getContext().getSourceManager());
PathDiagnosticPiece* P = new PathDiagnosticPiece(Pos, Msg);
if (Expr* Exp = dyn_cast<Expr>(S))
P->addRange(Exp->getSourceRange());
return P;
}
// Determine if the typestate has changed.
RefVal PrevV = PrevB.SlimFind(Sym)->getValue().second;
if (PrevV == CurrV)
return NULL;
// The typestate has changed.
std::ostringstream os;
switch (CurrV.getKind()) {
case RefVal::Owned:
case RefVal::NotOwned:
assert (PrevV.getKind() == CurrV.getKind());
if (PrevV.getCount() > CurrV.getCount())
os << "Reference count decremented.";
else
os << "Reference count incremented.";
if (unsigned Count = GetCount(CurrV)) {
os << " Object has +" << Count;
if (Count > 1)
os << " retain counts.";
else
os << " retain count.";
}
Msg = os.str().c_str();
break;
case RefVal::Released:
Msg = "Object released.";
break;
case RefVal::ReturnedOwned:
Msg = "Object returned to caller as owning reference (single retain count"
" transferred to caller).";
break;
case RefVal::ReturnedNotOwned:
Msg = "Object returned to caller with a +0 (non-owning) retain count.";
break;
default:
return NULL;
}
Stmt* S = cast<PostStmt>(N->getLocation()).getStmt();
FullSourceLoc Pos(S->getLocStart(), BR.getContext().getSourceManager());
PathDiagnosticPiece* P = new PathDiagnosticPiece(Pos, Msg);
// Add the range by scanning the children of the statement for any bindings
// to Sym.
ValueStateManager& VSM = BR.getEngine().getStateManager();
for (Stmt::child_iterator I = S->child_begin(), E = S->child_end(); I!=E; ++I)
if (Expr* Exp = dyn_cast_or_null<Expr>(*I)) {
RVal X = VSM.GetRVal(CurrSt, Exp);
if (lval::SymbolVal* SV = dyn_cast<lval::SymbolVal>(&X))
if (SV->getSymbol() == Sym) {
P->addRange(Exp->getSourceRange()); break;
}
}
return P;
}
PathDiagnosticPiece* CFRefReport::getEndPath(BugReporter& BR,
ExplodedNode<ValueState>* EndN) {
if (!getBugType().isLeak())
return RangedBugReport::getEndPath(BR, EndN);
typedef CFRefCount::RefBindings RefBindings;
// Get the retain count.
unsigned long RetCount = 0;
{
ValueState* St = EndN->getState();
RefBindings B = RefBindings((RefBindings::TreeTy*) St->CheckerState);
RefBindings::TreeTy* T = B.SlimFind(Sym);
assert (T);
RetCount = GetCount(T->getValue().second);
}
// We are a leak. Walk up the graph to get to the first node where the
// symbol appeared.
ExplodedNode<ValueState>* N = EndN;
ExplodedNode<ValueState>* Last = N;
// Find the first node that referred to the tracked symbol. We also
// try and find the first VarDecl the value was stored to.
VarDecl* FirstDecl = 0;
while (N) {
ValueState* St = N->getState();
RefBindings B = RefBindings((RefBindings::TreeTy*) St->CheckerState);
RefBindings::TreeTy* T = B.SlimFind(Sym);
if (!T)
break;
VarDecl* VD = 0;
// Determine if there is an LVal binding to the symbol.
for (ValueState::vb_iterator I=St->vb_begin(), E=St->vb_end(); I!=E; ++I) {
if (!isa<lval::SymbolVal>(I->second) // Is the value a symbol?
|| cast<lval::SymbolVal>(I->second).getSymbol() != Sym)
continue;
if (VD) { // Multiple decls map to this symbol.
VD = 0;
break;
}
VD = I->first;
}
if (VD) FirstDecl = VD;
Last = N;
N = N->pred_empty() ? NULL : *(N->pred_begin());
}
// Get the allocate site.
assert (Last);
Stmt* FirstStmt = cast<PostStmt>(Last->getLocation()).getStmt();
SourceManager& SMgr = BR.getContext().getSourceManager();
unsigned AllocLine = SMgr.getLogicalLineNumber(FirstStmt->getLocStart());
// Get the leak site. We may have multiple ExplodedNodes (one with the
// leak) that occur on the same line number; if the node with the leak
// has any immediate predecessor nodes with the same line number, find
// any transitive-successors that have a different statement and use that
// line number instead. This avoids emiting a diagnostic like:
//
// // 'y' is leaked.
// int x = foo(y);
//
// instead we want:
//
// int x = foo(y);
// // 'y' is leaked.
Stmt* S = getStmt(BR); // This is the statement where the leak occured.
assert (S);
unsigned EndLine = SMgr.getLogicalLineNumber(S->getLocStart());
// Look in the *trimmed* graph at the immediate predecessor of EndN. Does
// it occur on the same line?
PathDiagnosticPiece::DisplayHint Hint = PathDiagnosticPiece::Above;
assert (!EndN->pred_empty()); // Not possible to have 0 predecessors.
ExplodedNode<ValueState> *Pred = *(EndN->pred_begin());
ProgramPoint PredPos = Pred->getLocation();
if (PostStmt* PredPS = dyn_cast<PostStmt>(&PredPos)) {
Stmt* SPred = PredPS->getStmt();
// Predecessor at same line?
if (SMgr.getLogicalLineNumber(SPred->getLocStart()) != EndLine) {
Hint = PathDiagnosticPiece::Below;
S = SPred;
}
}
// Generate the diagnostic.
FullSourceLoc L( S->getLocStart(), SMgr);
std::ostringstream os;
os << "Object allocated on line " << AllocLine;
if (FirstDecl)
os << " and stored into '" << FirstDecl->getName() << '\'';
os << " is no longer referenced after this point and has a retain count of +"
<< RetCount << " (object leaked).";
return new PathDiagnosticPiece(L, os.str(), Hint);
}
void UseAfterRelease::EmitWarnings(BugReporter& BR) {
for (CFRefCount::use_after_iterator I = TF.use_after_begin(),
E = TF.use_after_end(); I != E; ++I) {
CFRefReport report(*this, I->first, I->second.second);
report.addRange(I->second.first->getSourceRange());
BR.EmitWarning(report);
}
}
void BadRelease::EmitWarnings(BugReporter& BR) {
for (CFRefCount::bad_release_iterator I = TF.bad_release_begin(),
E = TF.bad_release_end(); I != E; ++I) {
CFRefReport report(*this, I->first, I->second.second);
report.addRange(I->second.first->getSourceRange());
BR.EmitWarning(report);
}
}
void Leak::EmitWarnings(BugReporter& BR) {
for (CFRefCount::leaks_iterator I = TF.leaks_begin(),
E = TF.leaks_end(); I != E; ++I) {
std::vector<SymbolID>& SymV = *(I->second);
unsigned n = SymV.size();
for (unsigned i = 0; i < n; ++i) {
CFRefReport report(*this, I->first, SymV[i]);
BR.EmitWarning(report);
}
}
}
void Leak::GetErrorNodes(std::vector<ExplodedNode<ValueState>*>& Nodes) {
for (CFRefCount::leaks_iterator I=TF.leaks_begin(), E=TF.leaks_end();
I!=E; ++I)
Nodes.push_back(I->first);
}
//===----------------------------------------------------------------------===//
// Transfer function creation for external clients.
//===----------------------------------------------------------------------===//
GRTransferFuncs* clang::MakeCFRefCountTF(ASTContext& Ctx, bool GCEnabled,
bool StandardWarnings,
const LangOptions& lopts) {
return new CFRefCount(Ctx, GCEnabled, StandardWarnings, lopts);
}