llvm-project/clang/lib/StaticAnalyzer/Checkers/MacOSXAPIChecker.cpp

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4.7 KiB
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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 Apple APIs.
//
// FIXME: What's currently in BasicObjCFoundationChecks.cpp should be migrated
// to here, using the new Checker interface.
//
//===----------------------------------------------------------------------===//
#include "ClangSACheckers.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
using namespace ento;
namespace {
class MacOSXAPIChecker : public Checker< check::PreStmt<CallExpr> > {
mutable std::unique_ptr<BugType> BT_dispatchOnce;
public:
void checkPreStmt(const CallExpr *CE, CheckerContext &C) const;
void CheckDispatchOnce(CheckerContext &C, const CallExpr *CE,
StringRef FName) const;
typedef void (MacOSXAPIChecker::*SubChecker)(CheckerContext &,
const CallExpr *,
StringRef FName) const;
};
} //end anonymous namespace
//===----------------------------------------------------------------------===//
// dispatch_once and dispatch_once_f
//===----------------------------------------------------------------------===//
void MacOSXAPIChecker::CheckDispatchOnce(CheckerContext &C, const CallExpr *CE,
StringRef FName) const {
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.
ProgramStateRef state = C.getState();
const MemRegion *R =
state->getSVal(CE->getArg(0), C.getLocationContext()).getAsRegion();
if (!R || !isa<StackSpaceRegion>(R->getMemorySpace()))
return;
ExplodedNode *N = C.generateErrorNode(state);
if (!N)
return;
if (!BT_dispatchOnce)
BT_dispatchOnce.reset(new BugType(this, "Improper use of 'dispatch_once'",
"API Misuse (Apple)"));
// Handle _dispatch_once. In some versions of the OS X SDK we have the case
// that dispatch_once is a macro that wraps a call to _dispatch_once.
// _dispatch_once is then a function which then calls the real dispatch_once.
// Users do not care; they just want the warning at the top-level call.
if (CE->getLocStart().isMacroID()) {
StringRef TrimmedFName = FName.ltrim('_');
if (TrimmedFName != FName)
FName = TrimmedFName;
}
SmallString<256> S;
llvm::raw_svector_ostream os(S);
os << "Call to '" << FName << "' 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'?";
auto report = llvm::make_unique<BugReport>(*BT_dispatchOnce, os.str(), N);
report->addRange(CE->getArg(0)->getSourceRange());
C.emitReport(std::move(report));
}
//===----------------------------------------------------------------------===//
// Central dispatch function.
//===----------------------------------------------------------------------===//
void MacOSXAPIChecker::checkPreStmt(const CallExpr *CE,
CheckerContext &C) const {
StringRef Name = C.getCalleeName(CE);
if (Name.empty())
return;
SubChecker SC =
llvm::StringSwitch<SubChecker>(Name)
.Cases("dispatch_once",
"_dispatch_once",
"dispatch_once_f",
&MacOSXAPIChecker::CheckDispatchOnce)
.Default(nullptr);
if (SC)
(this->*SC)(C, CE, Name);
}
//===----------------------------------------------------------------------===//
// Registration.
//===----------------------------------------------------------------------===//
void ento::registerMacOSXAPIChecker(CheckerManager &mgr) {
mgr.registerChecker<MacOSXAPIChecker>();
}