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 "SelectorExtras.h" 17 #include "clang/AST/Attr.h" 18 #include "clang/StaticAnalyzer/Core/Checker.h" 19 #include "clang/StaticAnalyzer/Core/CheckerManager.h" 20 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" 21 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" 22 #include "llvm/ADT/StringSwitch.h" 23 #include <cstdarg> 24 25 using namespace clang; 26 using namespace ento; 27 28 namespace { 29 30 class NoReturnFunctionChecker : public Checker< check::PostCall, 31 check::PostObjCMessage > { 32 mutable Selector HandleFailureInFunctionSel; 33 mutable Selector HandleFailureInMethodSel; 34 public: 35 void checkPostCall(const CallEvent &CE, CheckerContext &C) const; 36 void checkPostObjCMessage(const ObjCMethodCall &msg, CheckerContext &C) const; 37 }; 38 39 } 40 41 void NoReturnFunctionChecker::checkPostCall(const CallEvent &CE, 42 CheckerContext &C) const { 43 bool BuildSinks = false; 44 45 if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(CE.getDecl())) 46 BuildSinks = FD->hasAttr<AnalyzerNoReturnAttr>() || FD->isNoReturn(); 47 48 const Expr *Callee = CE.getOriginExpr(); 49 if (!BuildSinks && Callee) 50 BuildSinks = getFunctionExtInfo(Callee->getType()).getNoReturn(); 51 52 if (!BuildSinks && CE.isGlobalCFunction()) { 53 if (const IdentifierInfo *II = CE.getCalleeIdentifier()) { 54 // HACK: Some functions are not marked noreturn, and don't return. 55 // Here are a few hardwired ones. If this takes too long, we can 56 // potentially cache these results. 57 BuildSinks 58 = llvm::StringSwitch<bool>(StringRef(II->getName())) 59 .Case("exit", true) 60 .Case("panic", true) 61 .Case("error", true) 62 .Case("Assert", true) 63 // FIXME: This is just a wrapper around throwing an exception. 64 // Eventually inter-procedural analysis should handle this easily. 65 .Case("ziperr", true) 66 .Case("assfail", true) 67 .Case("db_error", true) 68 .Case("__assert", true) 69 .Case("__assert2", true) 70 // For the purpose of static analysis, we do not care that 71 // this MSVC function will return if the user decides to continue. 72 .Case("_wassert", true) 73 .Case("__assert_rtn", true) 74 .Case("__assert_fail", true) 75 .Case("dtrace_assfail", true) 76 .Case("yy_fatal_error", true) 77 .Case("_XCAssertionFailureHandler", true) 78 .Case("_DTAssertionFailureHandler", true) 79 .Case("_TSAssertionFailureHandler", true) 80 .Default(false); 81 } 82 } 83 84 if (BuildSinks) 85 C.generateSink(C.getState(), C.getPredecessor()); 86 } 87 88 void NoReturnFunctionChecker::checkPostObjCMessage(const ObjCMethodCall &Msg, 89 CheckerContext &C) const { 90 // Check if the method is annotated with analyzer_noreturn. 91 if (const ObjCMethodDecl *MD = Msg.getDecl()) { 92 MD = MD->getCanonicalDecl(); 93 if (MD->hasAttr<AnalyzerNoReturnAttr>()) { 94 C.generateSink(C.getState(), C.getPredecessor()); 95 return; 96 } 97 } 98 99 // HACK: This entire check is to handle two messages in the Cocoa frameworks: 100 // -[NSAssertionHandler 101 // handleFailureInMethod:object:file:lineNumber:description:] 102 // -[NSAssertionHandler 103 // handleFailureInFunction:file:lineNumber:description:] 104 // Eventually these should be annotated with __attribute__((noreturn)). 105 // Because ObjC messages use dynamic dispatch, it is not generally safe to 106 // assume certain methods can't return. In cases where it is definitely valid, 107 // see if you can mark the methods noreturn or analyzer_noreturn instead of 108 // adding more explicit checks to this method. 109 110 if (!Msg.isInstanceMessage()) 111 return; 112 113 const ObjCInterfaceDecl *Receiver = Msg.getReceiverInterface(); 114 if (!Receiver) 115 return; 116 if (!Receiver->getIdentifier()->isStr("NSAssertionHandler")) 117 return; 118 119 Selector Sel = Msg.getSelector(); 120 switch (Sel.getNumArgs()) { 121 default: 122 return; 123 case 4: 124 lazyInitKeywordSelector(HandleFailureInFunctionSel, C.getASTContext(), 125 "handleFailureInFunction", "file", "lineNumber", 126 "description", nullptr); 127 if (Sel != HandleFailureInFunctionSel) 128 return; 129 break; 130 case 5: 131 lazyInitKeywordSelector(HandleFailureInMethodSel, C.getASTContext(), 132 "handleFailureInMethod", "object", "file", 133 "lineNumber", "description", nullptr); 134 if (Sel != HandleFailureInMethodSel) 135 return; 136 break; 137 } 138 139 // If we got here, it's one of the messages we care about. 140 C.generateSink(C.getState(), C.getPredecessor()); 141 } 142 143 void ento::registerNoReturnFunctionChecker(CheckerManager &mgr) { 144 mgr.registerChecker<NoReturnFunctionChecker>(); 145 } 146