1 //== ReturnUndefChecker.cpp -------------------------------------*- 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 file defines ReturnUndefChecker, which is a path-sensitive
11 // check which looks for undefined or garbage values being returned to the
12 // caller.
13 //
14 //===----------------------------------------------------------------------===//
15
16 #include "ClangSACheckers.h"
17 #include "clang/StaticAnalyzer/Core/Checker.h"
18 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
19 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
20 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
21
22 using namespace clang;
23 using namespace ento;
24
25 namespace {
26 class ReturnUndefChecker :
27 public Checker< check::PreStmt<ReturnStmt> > {
28 mutable OwningPtr<BuiltinBug> BT;
29 public:
30 void checkPreStmt(const ReturnStmt *RS, CheckerContext &C) const;
31 };
32 }
33
checkPreStmt(const ReturnStmt * RS,CheckerContext & C) const34 void ReturnUndefChecker::checkPreStmt(const ReturnStmt *RS,
35 CheckerContext &C) const {
36
37 const Expr *RetE = RS->getRetValue();
38 if (!RetE)
39 return;
40
41 if (!C.getState()->getSVal(RetE, C.getLocationContext()).isUndef())
42 return;
43
44 ExplodedNode *N = C.generateSink();
45
46 if (!N)
47 return;
48
49 if (!BT)
50 BT.reset(new BuiltinBug("Garbage return value",
51 "Undefined or garbage value returned to caller"));
52
53 BugReport *report =
54 new BugReport(*BT, BT->getDescription(), N);
55
56 report->addRange(RetE->getSourceRange());
57 bugreporter::trackNullOrUndefValue(N, RetE, *report);
58
59 C.EmitReport(report);
60 }
61
registerReturnUndefChecker(CheckerManager & mgr)62 void ento::registerReturnUndefChecker(CheckerManager &mgr) {
63 mgr.registerChecker<ReturnUndefChecker>();
64 }
65