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 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
CheckDispatchOnce(CheckerContext & C,const CallExpr * CE,StringRef FName) const52 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 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
checkPreStmt(const CallExpr * CE,CheckerContext & C) const94 void 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
registerMacOSXAPIChecker(CheckerManager & mgr)114 void ento::registerMacOSXAPIChecker(CheckerManager &mgr) {
115 mgr.registerChecker<MacOSXAPIChecker>();
116 }
117