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// MacOSXAPIChecker.h - Checks proper use of various MacOS X APIs --*- C++ -*-//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This defines MacOSXAPIChecker, which is an assortment of checks on calls
// to various, widely used Mac OS X functions.
//
// FIXME: What's currently in BasicObjCFoundationChecks.cpp should be migrated
// to here, using the new Checker interface.
//
//===----------------------------------------------------------------------===//
#include "GRExprEngineInternalChecks.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Checker/BugReporter/BugType.h"
#include "clang/Checker/PathSensitive/CheckerVisitor.h"
#include "clang/Checker/PathSensitive/GRStateTrait.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
namespace {
class MacOSXAPIChecker : public CheckerVisitor<MacOSXAPIChecker> {
enum SubChecks {
DispatchOnce = 0,
DispatchOnceF,
NumChecks
};
BugType *BTypes[NumChecks];
public:
MacOSXAPIChecker() { memset(BTypes, 0, sizeof(*BTypes) * NumChecks); }
static void *getTag() { static unsigned tag = 0; return &tag; }
void PreVisitCallExpr(CheckerContext &C, const CallExpr *CE);
};
} //end anonymous namespace
void clang::RegisterMacOSXAPIChecker(GRExprEngine &Eng) {
if (Eng.getContext().Target.getTriple().getVendor() == llvm::Triple::Apple)
Eng.registerCheck(new MacOSXAPIChecker());
}
//===----------------------------------------------------------------------===//
// dispatch_once and dispatch_once_f
//===----------------------------------------------------------------------===//
static void CheckDispatchOnce(CheckerContext &C, const CallExpr *CE,
BugType *&BT, const IdentifierInfo *FI) {
if (!BT) {
llvm::SmallString<128> S;
llvm::raw_svector_ostream os(S);
os << "Improper use of '" << FI->getName() << '\'';
BT = new BugType(os.str(), "Mac OS X API");
}
if (CE->getNumArgs() < 1)
return;
// Check if the first argument is stack allocated. If so, issue a warning
// because that's likely to be bad news.
const GRState *state = C.getState();
const MemRegion *R = state->getSVal(CE->getArg(0)).getAsRegion();
if (!R || !isa<StackSpaceRegion>(R->getMemorySpace()))
return;
ExplodedNode *N = C.GenerateSink(state);
if (!N)
return;
llvm::SmallString<256> S;
llvm::raw_svector_ostream os(S);
os << "Call to '" << FI->getName() << "' uses";
if (const VarRegion *VR = dyn_cast<VarRegion>(R))
os << " the local variable '" << VR->getDecl()->getName() << '\'';
else
os << " stack allocated memory";
os << " for the predicate value. Using such transient memory for "
"the predicate is potentially dangerous.";
if (isa<VarRegion>(R) && isa<StackLocalsSpaceRegion>(R->getMemorySpace()))
os << " Perhaps you intended to declare the variable as 'static'?";
EnhancedBugReport *report = new EnhancedBugReport(*BT, os.str(), N);
report->addRange(CE->getArg(0)->getSourceRange());
C.EmitReport(report);
}
//===----------------------------------------------------------------------===//
// Central dispatch function.
//===----------------------------------------------------------------------===//
typedef void (*SubChecker)(CheckerContext &C, const CallExpr *CE, BugType *&BT,
const IdentifierInfo *FI);
namespace {
class SubCheck {
SubChecker SC;
BugType **BT;
public:
SubCheck(SubChecker sc, BugType *& bt) : SC(sc), BT(&bt) {}
SubCheck() : SC(NULL), BT(NULL) {}
void run(CheckerContext &C, const CallExpr *CE,
const IdentifierInfo *FI) const {
if (SC)
SC(C, CE, *BT, FI);
}
};
} // end anonymous namespace
void MacOSXAPIChecker::PreVisitCallExpr(CheckerContext &C, const CallExpr *CE) {
// FIXME: Mostly copy and paste from UnixAPIChecker. Should refactor.
const GRState *state = C.getState();
const Expr *Callee = CE->getCallee();
const FunctionTextRegion *Fn =
dyn_cast_or_null<FunctionTextRegion>(state->getSVal(Callee).getAsRegion());
if (!Fn)
return;
const IdentifierInfo *FI = Fn->getDecl()->getIdentifier();
if (!FI)
return;
const SubCheck &SC =
llvm::StringSwitch<SubCheck>(FI->getName())
.Case("dispatch_once", SubCheck(CheckDispatchOnce, BTypes[DispatchOnce]))
.Case("dispatch_once_f", SubCheck(CheckDispatchOnce,
BTypes[DispatchOnceF]))
.Default(SubCheck());
SC.run(C, CE, FI);
}
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