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1 //=== NoReturnFunctionChecker.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 defines NoReturnFunctionChecker, which evaluates functions that do not
11 // return to the caller.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "ClangSACheckers.h"
16 #include "clang/StaticAnalyzer/Core/Checker.h"
17 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
18 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
19 #include "llvm/ADT/StringSwitch.h"
20 
21 using namespace clang;
22 using namespace ento;
23 
24 namespace {
25 
26 class NoReturnFunctionChecker : public Checker< check::PostStmt<CallExpr> > {
27 public:
28   void checkPostStmt(const CallExpr *CE, CheckerContext &C) const;
29 };
30 
31 }
32 
checkPostStmt(const CallExpr * CE,CheckerContext & C) const33 void NoReturnFunctionChecker::checkPostStmt(const CallExpr *CE,
34                                             CheckerContext &C) const {
35   const GRState *state = C.getState();
36   const Expr *Callee = CE->getCallee();
37 
38   bool BuildSinks = getFunctionExtInfo(Callee->getType()).getNoReturn();
39 
40   if (!BuildSinks) {
41     SVal L = state->getSVal(Callee);
42     const FunctionDecl *FD = L.getAsFunctionDecl();
43     if (!FD)
44       return;
45 
46     if (FD->getAttr<AnalyzerNoReturnAttr>())
47       BuildSinks = true;
48     else if (const IdentifierInfo *II = FD->getIdentifier()) {
49       // HACK: Some functions are not marked noreturn, and don't return.
50       //  Here are a few hardwired ones.  If this takes too long, we can
51       //  potentially cache these results.
52       BuildSinks
53         = llvm::StringSwitch<bool>(llvm::StringRef(II->getName()))
54             .Case("exit", true)
55             .Case("panic", true)
56             .Case("error", true)
57             .Case("Assert", true)
58             // FIXME: This is just a wrapper around throwing an exception.
59             //  Eventually inter-procedural analysis should handle this easily.
60             .Case("ziperr", true)
61             .Case("assfail", true)
62             .Case("db_error", true)
63             .Case("__assert", true)
64             .Case("__assert_rtn", true)
65             .Case("__assert_fail", true)
66             .Case("dtrace_assfail", true)
67             .Case("yy_fatal_error", true)
68             .Case("_XCAssertionFailureHandler", true)
69             .Case("_DTAssertionFailureHandler", true)
70             .Case("_TSAssertionFailureHandler", true)
71             .Default(false);
72     }
73   }
74 
75   if (BuildSinks)
76     C.generateSink(CE);
77 }
78 
registerNoReturnFunctionChecker(CheckerManager & mgr)79 void ento::registerNoReturnFunctionChecker(CheckerManager &mgr) {
80   mgr.registerChecker<NoReturnFunctionChecker>();
81 }
82