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 29 using namespace clang; 30 using namespace ento; 31 32 namespace { 33 class MacOSXAPIChecker : public Checker< check::PreStmt<CallExpr> > { 34 mutable llvm::OwningPtr<BugType> BT_dispatchOnce; 35 36 public: 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 52 void 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 const ProgramState *state = C.getState(); 60 const MemRegion *R = state->getSVal(CE->getArg(0)).getAsRegion(); 61 if (!R || !isa<StackSpaceRegion>(R->getMemorySpace())) 62 return; 63 64 ExplodedNode *N = C.generateSink(state); 65 if (!N) 66 return; 67 68 if (!BT_dispatchOnce) 69 BT_dispatchOnce.reset(new BugType("Improper use of 'dispatch_once'", 70 "Mac OS X API")); 71 72 llvm::SmallString<256> S; 73 llvm::raw_svector_ostream os(S); 74 os << "Call to '" << FName << "' uses"; 75 if (const VarRegion *VR = dyn_cast<VarRegion>(R)) 76 os << " the local variable '" << VR->getDecl()->getName() << '\''; 77 else 78 os << " stack allocated memory"; 79 os << " for the predicate value. Using such transient memory for " 80 "the predicate is potentially dangerous."; 81 if (isa<VarRegion>(R) && isa<StackLocalsSpaceRegion>(R->getMemorySpace())) 82 os << " Perhaps you intended to declare the variable as 'static'?"; 83 84 BugReport *report = new BugReport(*BT_dispatchOnce, os.str(), N); 85 report->addRange(CE->getArg(0)->getSourceRange()); 86 C.EmitReport(report); 87 } 88 89 //===----------------------------------------------------------------------===// 90 // Central dispatch function. 91 //===----------------------------------------------------------------------===// 92 93 void MacOSXAPIChecker::checkPreStmt(const CallExpr *CE, 94 CheckerContext &C) const { 95 StringRef Name = C.getCalleeName(CE); 96 if (Name.empty()) 97 return; 98 99 SubChecker SC = 100 llvm::StringSwitch<SubChecker>(Name) 101 .Cases("dispatch_once", "dispatch_once_f", 102 &MacOSXAPIChecker::CheckDispatchOnce) 103 .Default(NULL); 104 105 if (SC) 106 (this->*SC)(C, CE, Name); 107 } 108 109 //===----------------------------------------------------------------------===// 110 // Registration. 111 //===----------------------------------------------------------------------===// 112 113 void ento::registerMacOSXAPIChecker(CheckerManager &mgr) { 114 mgr.registerChecker<MacOSXAPIChecker>(); 115 } 116