1// MacOSXAPIChecker.h - Checks proper use of various MacOS X APIs --*- C++ -*-// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This defines MacOSXAPIChecker, which is an assortment of checks on calls 11// to various, widely used Mac OS X functions. 12// 13// FIXME: What's currently in BasicObjCFoundationChecks.cpp should be migrated 14// to here, using the new Checker interface. 15// 16//===----------------------------------------------------------------------===// 17 18#include "ClangSACheckers.h" 19#include "clang/StaticAnalyzer/Core/Checker.h" 20#include "clang/StaticAnalyzer/Core/CheckerManager.h" 21#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" 22#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" 23#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" 24#include "clang/Basic/TargetInfo.h" 25#include "llvm/ADT/SmallString.h" 26#include "llvm/ADT/StringSwitch.h" 27#include "llvm/Support/raw_ostream.h" 28 29using namespace clang; 30using namespace ento; 31 32namespace { 33class MacOSXAPIChecker : public Checker< check::PreStmt<CallExpr> > { 34 mutable OwningPtr<BugType> BT_dispatchOnce; 35 36public: 37 void checkPreStmt(const CallExpr *CE, CheckerContext &C) const; 38 39 void CheckDispatchOnce(CheckerContext &C, const CallExpr *CE, 40 StringRef FName) const; 41 42 typedef void (MacOSXAPIChecker::*SubChecker)(CheckerContext &, 43 const CallExpr *, 44 StringRef FName) const; 45}; 46} //end anonymous namespace 47 48//===----------------------------------------------------------------------===// 49// dispatch_once and dispatch_once_f 50//===----------------------------------------------------------------------===// 51 52void MacOSXAPIChecker::CheckDispatchOnce(CheckerContext &C, const CallExpr *CE, 53 StringRef FName) const { 54 if (CE->getNumArgs() < 1) 55 return; 56 57 // Check if the first argument is stack allocated. If so, issue a warning 58 // because that's likely to be bad news. 59 ProgramStateRef state = C.getState(); 60 const MemRegion *R = 61 state->getSVal(CE->getArg(0), C.getLocationContext()).getAsRegion(); 62 if (!R || !isa<StackSpaceRegion>(R->getMemorySpace())) 63 return; 64 65 ExplodedNode *N = C.generateSink(state); 66 if (!N) 67 return; 68 69 if (!BT_dispatchOnce) 70 BT_dispatchOnce.reset(new BugType("Improper use of 'dispatch_once'", 71 "Mac OS X API")); 72 73 SmallString<256> S; 74 llvm::raw_svector_ostream os(S); 75 os << "Call to '" << FName << "' uses"; 76 if (const VarRegion *VR = dyn_cast<VarRegion>(R)) 77 os << " the local variable '" << VR->getDecl()->getName() << '\''; 78 else 79 os << " stack allocated memory"; 80 os << " for the predicate value. Using such transient memory for " 81 "the predicate is potentially dangerous."; 82 if (isa<VarRegion>(R) && isa<StackLocalsSpaceRegion>(R->getMemorySpace())) 83 os << " Perhaps you intended to declare the variable as 'static'?"; 84 85 BugReport *report = new BugReport(*BT_dispatchOnce, os.str(), N); 86 report->addRange(CE->getArg(0)->getSourceRange()); 87 C.EmitReport(report); 88} 89 90//===----------------------------------------------------------------------===// 91// Central dispatch function. 92//===----------------------------------------------------------------------===// 93 94void MacOSXAPIChecker::checkPreStmt(const CallExpr *CE, 95 CheckerContext &C) const { 96 StringRef Name = C.getCalleeName(CE); 97 if (Name.empty()) 98 return; 99 100 SubChecker SC = 101 llvm::StringSwitch<SubChecker>(Name) 102 .Cases("dispatch_once", "dispatch_once_f", 103 &MacOSXAPIChecker::CheckDispatchOnce) 104 .Default(NULL); 105 106 if (SC) 107 (this->*SC)(C, CE, Name); 108} 109 110//===----------------------------------------------------------------------===// 111// Registration. 112//===----------------------------------------------------------------------===// 113 114void ento::registerMacOSXAPIChecker(CheckerManager &mgr) { 115 mgr.registerChecker<MacOSXAPIChecker>(); 116} 117