1 //==- ExprInspectionChecker.cpp - Used for regression tests ------*- 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 #include "ClangSACheckers.h"
11 #include "clang/StaticAnalyzer/Core/Checker.h"
12 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
13 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
14
15 using namespace clang;
16 using namespace ento;
17
18 namespace {
19 class ExprInspectionChecker : public Checker< eval::Call > {
20 mutable OwningPtr<BugType> BT;
21
22 void analyzerEval(const CallExpr *CE, CheckerContext &C) const;
23 void analyzerCheckInlined(const CallExpr *CE, CheckerContext &C) const;
24
25 typedef void (ExprInspectionChecker::*FnCheck)(const CallExpr *,
26 CheckerContext &C) const;
27
28 public:
29 bool evalCall(const CallExpr *CE, CheckerContext &C) const;
30 };
31 }
32
evalCall(const CallExpr * CE,CheckerContext & C) const33 bool ExprInspectionChecker::evalCall(const CallExpr *CE,
34 CheckerContext &C) const {
35 // These checks should have no effect on the surrounding environment
36 // (globals should not be invalidated, etc), hence the use of evalCall.
37 FnCheck Handler = llvm::StringSwitch<FnCheck>(C.getCalleeName(CE))
38 .Case("clang_analyzer_eval", &ExprInspectionChecker::analyzerEval)
39 .Case("clang_analyzer_checkInlined",
40 &ExprInspectionChecker::analyzerCheckInlined)
41 .Default(0);
42
43 if (!Handler)
44 return false;
45
46 (this->*Handler)(CE, C);
47 return true;
48 }
49
getArgumentValueString(const CallExpr * CE,CheckerContext & C)50 static const char *getArgumentValueString(const CallExpr *CE,
51 CheckerContext &C) {
52 if (CE->getNumArgs() == 0)
53 return "Missing assertion argument";
54
55 ExplodedNode *N = C.getPredecessor();
56 const LocationContext *LC = N->getLocationContext();
57 ProgramStateRef State = N->getState();
58
59 const Expr *Assertion = CE->getArg(0);
60 SVal AssertionVal = State->getSVal(Assertion, LC);
61
62 if (AssertionVal.isUndef())
63 return "UNDEFINED";
64
65 ProgramStateRef StTrue, StFalse;
66 llvm::tie(StTrue, StFalse) =
67 State->assume(cast<DefinedOrUnknownSVal>(AssertionVal));
68
69 if (StTrue) {
70 if (StFalse)
71 return "UNKNOWN";
72 else
73 return "TRUE";
74 } else {
75 if (StFalse)
76 return "FALSE";
77 else
78 llvm_unreachable("Invalid constraint; neither true or false.");
79 }
80 }
81
analyzerEval(const CallExpr * CE,CheckerContext & C) const82 void ExprInspectionChecker::analyzerEval(const CallExpr *CE,
83 CheckerContext &C) const {
84 ExplodedNode *N = C.getPredecessor();
85 const LocationContext *LC = N->getLocationContext();
86
87 // A specific instantiation of an inlined function may have more constrained
88 // values than can generally be assumed. Skip the check.
89 if (LC->getCurrentStackFrame()->getParent() != 0)
90 return;
91
92 if (!BT)
93 BT.reset(new BugType("Checking analyzer assumptions", "debug"));
94
95 BugReport *R = new BugReport(*BT, getArgumentValueString(CE, C), N);
96 C.EmitReport(R);
97 }
98
analyzerCheckInlined(const CallExpr * CE,CheckerContext & C) const99 void ExprInspectionChecker::analyzerCheckInlined(const CallExpr *CE,
100 CheckerContext &C) const {
101 ExplodedNode *N = C.getPredecessor();
102 const LocationContext *LC = N->getLocationContext();
103
104 // An inlined function could conceivably also be analyzed as a top-level
105 // function. We ignore this case and only emit a message (TRUE or FALSE)
106 // when we are analyzing it as an inlined function. This means that
107 // clang_analyzer_checkInlined(true) should always print TRUE, but
108 // clang_analyzer_checkInlined(false) should never actually print anything.
109 if (LC->getCurrentStackFrame()->getParent() == 0)
110 return;
111
112 if (!BT)
113 BT.reset(new BugType("Checking analyzer assumptions", "debug"));
114
115 BugReport *R = new BugReport(*BT, getArgumentValueString(CE, C), N);
116 C.EmitReport(R);
117 }
118
registerExprInspectionChecker(CheckerManager & Mgr)119 void ento::registerExprInspectionChecker(CheckerManager &Mgr) {
120 Mgr.registerChecker<ExprInspectionChecker>();
121 }
122
123