1 //===-- DebugIteratorModeling.cpp ---------------------------------*- C++ -*--//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Defines a checker for debugging iterator modeling.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
14 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
15 #include "clang/StaticAnalyzer/Core/Checker.h"
16 #include "clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h"
17 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
18 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
19
20 #include "Iterator.h"
21
22 using namespace clang;
23 using namespace ento;
24 using namespace iterator;
25
26 namespace {
27
28 class DebugIteratorModeling
29 : public Checker<eval::Call> {
30
31 std::unique_ptr<BugType> DebugMsgBugType;
32
33 template <typename Getter>
34 void analyzerIteratorDataField(const CallExpr *CE, CheckerContext &C,
35 Getter get, SVal Default) const;
36 void analyzerIteratorPosition(const CallExpr *CE, CheckerContext &C) const;
37 void analyzerIteratorContainer(const CallExpr *CE, CheckerContext &C) const;
38 void analyzerIteratorValidity(const CallExpr *CE, CheckerContext &C) const;
39 ExplodedNode *reportDebugMsg(llvm::StringRef Msg, CheckerContext &C) const;
40
41 typedef void (DebugIteratorModeling::*FnCheck)(const CallExpr *,
42 CheckerContext &) const;
43
44 CallDescriptionMap<FnCheck> Callbacks = {
45 {{{"clang_analyzer_iterator_position"}, 1},
46 &DebugIteratorModeling::analyzerIteratorPosition},
47 {{{"clang_analyzer_iterator_container"}, 1},
48 &DebugIteratorModeling::analyzerIteratorContainer},
49 {{{"clang_analyzer_iterator_validity"}, 1},
50 &DebugIteratorModeling::analyzerIteratorValidity},
51 };
52
53 public:
54 DebugIteratorModeling();
55
56 bool evalCall(const CallEvent &Call, CheckerContext &C) const;
57 };
58
59 } //namespace
60
DebugIteratorModeling()61 DebugIteratorModeling::DebugIteratorModeling() {
62 DebugMsgBugType.reset(
63 new BugType(this, "Checking analyzer assumptions", "debug",
64 /*SuppressOnSink=*/true));
65 }
66
evalCall(const CallEvent & Call,CheckerContext & C) const67 bool DebugIteratorModeling::evalCall(const CallEvent &Call,
68 CheckerContext &C) const {
69 const auto *CE = dyn_cast_or_null<CallExpr>(Call.getOriginExpr());
70 if (!CE)
71 return false;
72
73 const FnCheck *Handler = Callbacks.lookup(Call);
74 if (!Handler)
75 return false;
76
77 (this->**Handler)(CE, C);
78 return true;
79 }
80
81 template <typename Getter>
analyzerIteratorDataField(const CallExpr * CE,CheckerContext & C,Getter get,SVal Default) const82 void DebugIteratorModeling::analyzerIteratorDataField(const CallExpr *CE,
83 CheckerContext &C,
84 Getter get,
85 SVal Default) const {
86 if (CE->getNumArgs() == 0) {
87 reportDebugMsg("Missing iterator argument", C);
88 return;
89 }
90
91 auto State = C.getState();
92 SVal V = C.getSVal(CE->getArg(0));
93 const auto *Pos = getIteratorPosition(State, V);
94 if (Pos) {
95 State = State->BindExpr(CE, C.getLocationContext(), get(Pos));
96 } else {
97 State = State->BindExpr(CE, C.getLocationContext(), Default);
98 }
99 C.addTransition(State);
100 }
101
analyzerIteratorPosition(const CallExpr * CE,CheckerContext & C) const102 void DebugIteratorModeling::analyzerIteratorPosition(const CallExpr *CE,
103 CheckerContext &C) const {
104 auto &BVF = C.getSValBuilder().getBasicValueFactory();
105 analyzerIteratorDataField(CE, C, [](const IteratorPosition *P) {
106 return nonloc::SymbolVal(P->getOffset());
107 }, nonloc::ConcreteInt(BVF.getValue(llvm::APSInt::get(0))));
108 }
109
analyzerIteratorContainer(const CallExpr * CE,CheckerContext & C) const110 void DebugIteratorModeling::analyzerIteratorContainer(const CallExpr *CE,
111 CheckerContext &C) const {
112 auto &BVF = C.getSValBuilder().getBasicValueFactory();
113 analyzerIteratorDataField(CE, C, [](const IteratorPosition *P) {
114 return loc::MemRegionVal(P->getContainer());
115 }, loc::ConcreteInt(BVF.getValue(llvm::APSInt::get(0))));
116 }
117
analyzerIteratorValidity(const CallExpr * CE,CheckerContext & C) const118 void DebugIteratorModeling::analyzerIteratorValidity(const CallExpr *CE,
119 CheckerContext &C) const {
120 auto &BVF = C.getSValBuilder().getBasicValueFactory();
121 analyzerIteratorDataField(CE, C, [&BVF](const IteratorPosition *P) {
122 return
123 nonloc::ConcreteInt(BVF.getValue(llvm::APSInt::get((P->isValid()))));
124 }, nonloc::ConcreteInt(BVF.getValue(llvm::APSInt::get(0))));
125 }
126
reportDebugMsg(llvm::StringRef Msg,CheckerContext & C) const127 ExplodedNode *DebugIteratorModeling::reportDebugMsg(llvm::StringRef Msg,
128 CheckerContext &C) const {
129 ExplodedNode *N = C.generateNonFatalErrorNode();
130 if (!N)
131 return nullptr;
132
133 auto &BR = C.getBugReporter();
134 BR.emitReport(std::make_unique<PathSensitiveBugReport>(*DebugMsgBugType,
135 Msg, N));
136 return N;
137 }
138
registerDebugIteratorModeling(CheckerManager & mgr)139 void ento::registerDebugIteratorModeling(CheckerManager &mgr) {
140 mgr.registerChecker<DebugIteratorModeling>();
141 }
142
shouldRegisterDebugIteratorModeling(const CheckerManager & mgr)143 bool ento::shouldRegisterDebugIteratorModeling(const CheckerManager &mgr) {
144 return true;
145 }
146