forked from OSchip/llvm-project
549 lines
16 KiB
C++
549 lines
16 KiB
C++
//== BasicObjCFoundationChecks.cpp - Simple Apple-Foundation checks -*- C++ -*--
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines BasicObjCFoundationChecks, a class that encapsulates
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// a set of simple checks to run on Objective-C code using Apple's Foundation
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// classes.
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//
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//===----------------------------------------------------------------------===//
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#include "BasicObjCFoundationChecks.h"
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#include "clang/Analysis/PathSensitive/ExplodedGraph.h"
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#include "clang/Analysis/PathSensitive/GRSimpleAPICheck.h"
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#include "clang/Analysis/PathSensitive/GRExprEngine.h"
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#include "clang/Analysis/PathSensitive/GRState.h"
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#include "clang/Analysis/PathSensitive/BugReporter.h"
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#include "clang/Analysis/PathSensitive/MemRegion.h"
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#include "clang/Analysis/PathDiagnostic.h"
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#include "clang/Analysis/LocalCheckers.h"
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#include "clang/AST/DeclObjC.h"
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#include "clang/AST/Expr.h"
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#include "clang/AST/ExprObjC.h"
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#include "clang/AST/ASTContext.h"
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#include "llvm/Support/Compiler.h"
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using namespace clang;
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static const ObjCInterfaceType* GetReceiverType(const ObjCMessageExpr* ME) {
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const Expr* Receiver = ME->getReceiver();
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if (!Receiver)
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return NULL;
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if (const ObjCObjectPointerType *PT =
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Receiver->getType()->getAsObjCObjectPointerType())
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return PT->getInterfaceType();
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return NULL;
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}
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static const char* GetReceiverNameType(const ObjCMessageExpr* ME) {
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const ObjCInterfaceType *ReceiverType = GetReceiverType(ME);
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return ReceiverType ? ReceiverType->getDecl()->getIdentifier()->getName()
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: NULL;
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}
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namespace {
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class VISIBILITY_HIDDEN APIMisuse : public BugType {
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public:
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APIMisuse(const char* name) : BugType(name, "API Misuse (Apple)") {}
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};
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class VISIBILITY_HIDDEN BasicObjCFoundationChecks : public GRSimpleAPICheck {
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APIMisuse *BT;
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BugReporter& BR;
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ASTContext &Ctx;
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bool isNSString(const ObjCInterfaceType *T, const char* suffix);
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bool AuditNSString(NodeTy* N, const ObjCMessageExpr* ME);
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void Warn(NodeTy* N, const Expr* E, const std::string& s);
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void WarnNilArg(NodeTy* N, const Expr* E);
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bool CheckNilArg(NodeTy* N, unsigned Arg);
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public:
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BasicObjCFoundationChecks(ASTContext& ctx, BugReporter& br)
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: BT(0), BR(br), Ctx(ctx) {}
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bool Audit(ExplodedNode<GRState>* N, GRStateManager&);
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private:
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void WarnNilArg(NodeTy* N, const ObjCMessageExpr* ME, unsigned Arg) {
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std::string sbuf;
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llvm::raw_string_ostream os(sbuf);
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os << "Argument to '" << GetReceiverNameType(ME) << "' method '"
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<< ME->getSelector().getAsString() << "' cannot be nil.";
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// Lazily create the BugType object for NilArg. This will be owned
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// by the BugReporter object 'BR' once we call BR.EmitWarning.
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if (!BT) BT = new APIMisuse("nil argument");
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RangedBugReport *R = new RangedBugReport(*BT, os.str().c_str(), N);
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R->addRange(ME->getArg(Arg)->getSourceRange());
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BR.EmitReport(R);
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}
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};
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} // end anonymous namespace
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GRSimpleAPICheck*
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clang::CreateBasicObjCFoundationChecks(ASTContext& Ctx, BugReporter& BR) {
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return new BasicObjCFoundationChecks(Ctx, BR);
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}
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bool BasicObjCFoundationChecks::Audit(ExplodedNode<GRState>* N,
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GRStateManager&) {
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const ObjCMessageExpr* ME =
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cast<ObjCMessageExpr>(cast<PostStmt>(N->getLocation()).getStmt());
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const ObjCInterfaceType *ReceiverType = GetReceiverType(ME);
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if (!ReceiverType)
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return false;
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const char* name = ReceiverType->getDecl()->getIdentifier()->getName();
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if (!name)
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return false;
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if (name[0] != 'N' || name[1] != 'S')
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return false;
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name += 2;
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// FIXME: Make all of this faster.
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if (isNSString(ReceiverType, name))
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return AuditNSString(N, ME);
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return false;
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}
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static inline bool isNil(SVal X) {
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return isa<loc::ConcreteInt>(X);
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}
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//===----------------------------------------------------------------------===//
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// Error reporting.
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//===----------------------------------------------------------------------===//
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bool BasicObjCFoundationChecks::CheckNilArg(NodeTy* N, unsigned Arg) {
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const ObjCMessageExpr* ME =
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cast<ObjCMessageExpr>(cast<PostStmt>(N->getLocation()).getStmt());
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const Expr * E = ME->getArg(Arg);
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if (isNil(N->getState()->getSVal(E))) {
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WarnNilArg(N, ME, Arg);
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return true;
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}
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return false;
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}
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//===----------------------------------------------------------------------===//
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// NSString checking.
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//===----------------------------------------------------------------------===//
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bool BasicObjCFoundationChecks::isNSString(const ObjCInterfaceType *T,
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const char* suffix) {
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return !strcmp("String", suffix) || !strcmp("MutableString", suffix);
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}
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bool BasicObjCFoundationChecks::AuditNSString(NodeTy* N,
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const ObjCMessageExpr* ME) {
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Selector S = ME->getSelector();
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if (S.isUnarySelector())
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return false;
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// FIXME: This is going to be really slow doing these checks with
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// lexical comparisons.
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std::string name = S.getAsString();
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assert (!name.empty());
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const char* cstr = &name[0];
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unsigned len = name.size();
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switch (len) {
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default:
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break;
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case 8:
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if (!strcmp(cstr, "compare:"))
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return CheckNilArg(N, 0);
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break;
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case 15:
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// FIXME: Checking for initWithFormat: will not work in most cases
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// yet because [NSString alloc] returns id, not NSString*. We will
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// need support for tracking expected-type information in the analyzer
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// to find these errors.
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if (!strcmp(cstr, "initWithFormat:"))
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return CheckNilArg(N, 0);
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break;
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case 16:
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if (!strcmp(cstr, "compare:options:"))
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return CheckNilArg(N, 0);
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break;
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case 22:
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if (!strcmp(cstr, "compare:options:range:"))
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return CheckNilArg(N, 0);
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break;
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case 23:
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if (!strcmp(cstr, "caseInsensitiveCompare:"))
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return CheckNilArg(N, 0);
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break;
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case 29:
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if (!strcmp(cstr, "compare:options:range:locale:"))
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return CheckNilArg(N, 0);
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break;
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case 37:
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if (!strcmp(cstr, "componentsSeparatedByCharactersInSet:"))
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return CheckNilArg(N, 0);
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break;
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}
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return false;
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}
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//===----------------------------------------------------------------------===//
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// Error reporting.
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//===----------------------------------------------------------------------===//
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namespace {
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class VISIBILITY_HIDDEN AuditCFNumberCreate : public GRSimpleAPICheck {
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APIMisuse* BT;
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// FIXME: Either this should be refactored into GRSimpleAPICheck, or
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// it should always be passed with a call to Audit. The latter
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// approach makes this class more stateless.
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ASTContext& Ctx;
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IdentifierInfo* II;
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BugReporter& BR;
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public:
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AuditCFNumberCreate(ASTContext& ctx, BugReporter& br)
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: BT(0), Ctx(ctx), II(&Ctx.Idents.get("CFNumberCreate")), BR(br){}
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~AuditCFNumberCreate() {}
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bool Audit(ExplodedNode<GRState>* N, GRStateManager&);
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private:
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void AddError(const TypedRegion* R, const Expr* Ex, ExplodedNode<GRState> *N,
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uint64_t SourceSize, uint64_t TargetSize, uint64_t NumberKind);
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};
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} // end anonymous namespace
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enum CFNumberType {
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kCFNumberSInt8Type = 1,
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kCFNumberSInt16Type = 2,
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kCFNumberSInt32Type = 3,
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kCFNumberSInt64Type = 4,
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kCFNumberFloat32Type = 5,
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kCFNumberFloat64Type = 6,
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kCFNumberCharType = 7,
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kCFNumberShortType = 8,
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kCFNumberIntType = 9,
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kCFNumberLongType = 10,
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kCFNumberLongLongType = 11,
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kCFNumberFloatType = 12,
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kCFNumberDoubleType = 13,
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kCFNumberCFIndexType = 14,
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kCFNumberNSIntegerType = 15,
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kCFNumberCGFloatType = 16
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};
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namespace {
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template<typename T>
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class Optional {
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bool IsKnown;
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T Val;
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public:
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Optional() : IsKnown(false), Val(0) {}
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Optional(const T& val) : IsKnown(true), Val(val) {}
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bool isKnown() const { return IsKnown; }
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const T& getValue() const {
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assert (isKnown());
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return Val;
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}
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operator const T&() const {
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return getValue();
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}
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};
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}
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static Optional<uint64_t> GetCFNumberSize(ASTContext& Ctx, uint64_t i) {
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static unsigned char FixedSize[] = { 8, 16, 32, 64, 32, 64 };
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if (i < kCFNumberCharType)
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return FixedSize[i-1];
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QualType T;
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switch (i) {
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case kCFNumberCharType: T = Ctx.CharTy; break;
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case kCFNumberShortType: T = Ctx.ShortTy; break;
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case kCFNumberIntType: T = Ctx.IntTy; break;
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case kCFNumberLongType: T = Ctx.LongTy; break;
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case kCFNumberLongLongType: T = Ctx.LongLongTy; break;
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case kCFNumberFloatType: T = Ctx.FloatTy; break;
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case kCFNumberDoubleType: T = Ctx.DoubleTy; break;
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case kCFNumberCFIndexType:
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case kCFNumberNSIntegerType:
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case kCFNumberCGFloatType:
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// FIXME: We need a way to map from names to Type*.
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default:
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return Optional<uint64_t>();
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}
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return Ctx.getTypeSize(T);
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}
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#if 0
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static const char* GetCFNumberTypeStr(uint64_t i) {
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static const char* Names[] = {
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"kCFNumberSInt8Type",
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"kCFNumberSInt16Type",
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"kCFNumberSInt32Type",
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"kCFNumberSInt64Type",
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"kCFNumberFloat32Type",
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"kCFNumberFloat64Type",
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"kCFNumberCharType",
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"kCFNumberShortType",
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"kCFNumberIntType",
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"kCFNumberLongType",
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"kCFNumberLongLongType",
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"kCFNumberFloatType",
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"kCFNumberDoubleType",
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"kCFNumberCFIndexType",
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"kCFNumberNSIntegerType",
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"kCFNumberCGFloatType"
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};
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return i <= kCFNumberCGFloatType ? Names[i-1] : "Invalid CFNumberType";
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}
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#endif
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bool AuditCFNumberCreate::Audit(ExplodedNode<GRState>* N,GRStateManager&){
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const CallExpr* CE =
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cast<CallExpr>(cast<PostStmt>(N->getLocation()).getStmt());
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const Expr* Callee = CE->getCallee();
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SVal CallV = N->getState()->getSVal(Callee);
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const FunctionDecl* FD = CallV.getAsFunctionDecl();
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if (!FD || FD->getIdentifier() != II || CE->getNumArgs()!=3)
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return false;
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// Get the value of the "theType" argument.
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SVal TheTypeVal = N->getState()->getSVal(CE->getArg(1));
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// FIXME: We really should allow ranges of valid theType values, and
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// bifurcate the state appropriately.
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nonloc::ConcreteInt* V = dyn_cast<nonloc::ConcreteInt>(&TheTypeVal);
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if (!V)
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return false;
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uint64_t NumberKind = V->getValue().getLimitedValue();
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Optional<uint64_t> TargetSize = GetCFNumberSize(Ctx, NumberKind);
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// FIXME: In some cases we can emit an error.
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if (!TargetSize.isKnown())
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return false;
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// Look at the value of the integer being passed by reference. Essentially
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// we want to catch cases where the value passed in is not equal to the
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// size of the type being created.
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SVal TheValueExpr = N->getState()->getSVal(CE->getArg(2));
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// FIXME: Eventually we should handle arbitrary locations. We can do this
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// by having an enhanced memory model that does low-level typing.
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loc::MemRegionVal* LV = dyn_cast<loc::MemRegionVal>(&TheValueExpr);
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if (!LV)
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return false;
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const TypedRegion* R = dyn_cast<TypedRegion>(LV->getBaseRegion());
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if (!R)
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return false;
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QualType T = Ctx.getCanonicalType(R->getValueType(Ctx));
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// FIXME: If the pointee isn't an integer type, should we flag a warning?
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// People can do weird stuff with pointers.
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if (!T->isIntegerType())
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return false;
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uint64_t SourceSize = Ctx.getTypeSize(T);
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// CHECK: is SourceSize == TargetSize
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if (SourceSize == TargetSize)
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return false;
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AddError(R, CE->getArg(2), N, SourceSize, TargetSize, NumberKind);
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// FIXME: We can actually create an abstract "CFNumber" object that has
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// the bits initialized to the provided values.
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return SourceSize < TargetSize;
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}
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void AuditCFNumberCreate::AddError(const TypedRegion* R, const Expr* Ex,
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ExplodedNode<GRState> *N,
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uint64_t SourceSize, uint64_t TargetSize,
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uint64_t NumberKind) {
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std::string sbuf;
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llvm::raw_string_ostream os(sbuf);
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os << (SourceSize == 8 ? "An " : "A ")
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<< SourceSize << " bit integer is used to initialize a CFNumber "
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"object that represents "
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<< (TargetSize == 8 ? "an " : "a ")
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<< TargetSize << " bit integer. ";
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if (SourceSize < TargetSize)
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os << (TargetSize - SourceSize)
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<< " bits of the CFNumber value will be garbage." ;
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else
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os << (SourceSize - TargetSize)
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<< " bits of the input integer will be lost.";
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// Lazily create the BugType object. This will be owned
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// by the BugReporter object 'BR' once we call BR.EmitWarning.
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if (!BT) BT = new APIMisuse("Bad use of CFNumberCreate");
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RangedBugReport *report = new RangedBugReport(*BT, os.str().c_str(), N);
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report->addRange(Ex->getSourceRange());
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BR.EmitReport(report);
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}
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GRSimpleAPICheck*
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clang::CreateAuditCFNumberCreate(ASTContext& Ctx, BugReporter& BR) {
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return new AuditCFNumberCreate(Ctx, BR);
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}
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//===----------------------------------------------------------------------===//
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// CFRetain/CFRelease auditing for null arguments.
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//===----------------------------------------------------------------------===//
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namespace {
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class VISIBILITY_HIDDEN AuditCFRetainRelease : public GRSimpleAPICheck {
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APIMisuse *BT;
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// FIXME: Either this should be refactored into GRSimpleAPICheck, or
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// it should always be passed with a call to Audit. The latter
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// approach makes this class more stateless.
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ASTContext& Ctx;
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IdentifierInfo *Retain, *Release;
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BugReporter& BR;
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public:
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AuditCFRetainRelease(ASTContext& ctx, BugReporter& br)
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: BT(0), Ctx(ctx),
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Retain(&Ctx.Idents.get("CFRetain")), Release(&Ctx.Idents.get("CFRelease")),
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BR(br){}
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~AuditCFRetainRelease() {}
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bool Audit(ExplodedNode<GRState>* N, GRStateManager&);
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};
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} // end anonymous namespace
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bool AuditCFRetainRelease::Audit(ExplodedNode<GRState>* N, GRStateManager&) {
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const CallExpr* CE = cast<CallExpr>(cast<PostStmt>(N->getLocation()).getStmt());
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// If the CallExpr doesn't have exactly 1 argument just give up checking.
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if (CE->getNumArgs() != 1)
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return false;
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// Check if we called CFRetain/CFRelease.
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const GRState* state = N->getState();
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SVal X = state->getSVal(CE->getCallee());
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const FunctionDecl* FD = X.getAsFunctionDecl();
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if (!FD)
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return false;
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const IdentifierInfo *FuncII = FD->getIdentifier();
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if (!(FuncII == Retain || FuncII == Release))
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return false;
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// Finally, check if the argument is NULL.
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// FIXME: We should be able to bifurcate the state here, as a successful
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// check will result in the value not being NULL afterwards.
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// FIXME: Need a way to register vistors for the BugReporter. Would like
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// to benefit from the same diagnostics that regular null dereference
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// reporting has.
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if (state->getStateManager().isEqual(state, CE->getArg(0), 0)) {
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if (!BT)
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BT = new APIMisuse("null passed to CFRetain/CFRelease");
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const char *description = (FuncII == Retain)
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? "Null pointer argument in call to CFRetain"
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: "Null pointer argument in call to CFRelease";
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RangedBugReport *report = new RangedBugReport(*BT, description, N);
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report->addRange(CE->getArg(0)->getSourceRange());
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BR.EmitReport(report);
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return true;
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}
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return false;
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}
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GRSimpleAPICheck*
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clang::CreateAuditCFRetainRelease(ASTContext& Ctx, BugReporter& BR) {
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return new AuditCFRetainRelease(Ctx, BR);
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}
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//===----------------------------------------------------------------------===//
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// Check registration.
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//===----------------------------------------------------------------------===//
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|
|
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void clang::RegisterAppleChecks(GRExprEngine& Eng) {
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|
ASTContext& Ctx = Eng.getContext();
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BugReporter &BR = Eng.getBugReporter();
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|
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Eng.AddCheck(CreateBasicObjCFoundationChecks(Ctx, BR),
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|
Stmt::ObjCMessageExprClass);
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Eng.AddCheck(CreateAuditCFNumberCreate(Ctx, BR), Stmt::CallExprClass);
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Eng.AddCheck(CreateAuditCFRetainRelease(Ctx, BR), Stmt::CallExprClass);
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RegisterNSErrorChecks(BR, Eng);
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}
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