clang/lib/StaticAnalyzer/Checkers/NoReturnFunctionChecker.cpp

   1 //=== NoReturnFunctionChecker.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 // This defines NoReturnFunctionChecker, which evaluates functions that do not
  10 // return to the caller.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
  15 #include "clang/AST/Attr.h"
  16 #include "clang/Analysis/SelectorExtras.h"
  17 #include "clang/StaticAnalyzer/Core/Checker.h"
  18 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
  19 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
  20 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
  21 #include "llvm/ADT/StringSwitch.h"
  22 #include <cstdarg>
  23
  24 using namespace clang;
  25 using namespace ento;
  26
  27 namespace {
  28
  29 class NoReturnFunctionChecker : public Checker< check::PostCall,
  30                                                 check::PostObjCMessage > {
  31   mutable Selector HandleFailureInFunctionSel;
  32   mutable Selector HandleFailureInMethodSel;
  33 public:
  34   void checkPostCall(const CallEvent &CE, CheckerContext &C) const;
  35   void checkPostObjCMessage(const ObjCMethodCall &msg, CheckerContext &C) const;
  36 };
  37
  38 }
  39
  40 void NoReturnFunctionChecker::checkPostCall(const CallEvent &CE,
  41                                             CheckerContext &C) const {
  42   bool BuildSinks = false;
  43
  44   if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(CE.getDecl()))
  45     BuildSinks = FD->hasAttr<AnalyzerNoReturnAttr>() || FD->isNoReturn();
  46
  47   if (const CallExpr *CExpr = dyn_cast_or_null<CallExpr>(CE.getOriginExpr());
  48       CExpr && !BuildSinks) {
  49     if (const Expr *C = CExpr->getCallee())
  50       BuildSinks = getFunctionExtInfo(C->getType()).getNoReturn();
  51   }
  52
  53   if (!BuildSinks && CE.isGlobalCFunction()) {
  54     if (const IdentifierInfo *II = CE.getCalleeIdentifier()) {
  55       // HACK: Some functions are not marked noreturn, and don't return.
  56       //  Here are a few hardwired ones.  If this takes too long, we can
  57       //  potentially cache these results.
  58       BuildSinks
  59         = llvm::StringSwitch<bool>(StringRef(II->getName()))
  60             .Case("exit", true)
  61             .Case("panic", true)
  62             .Case("error", true)
  63             .Case("Assert", true)
  64             // FIXME: This is just a wrapper around throwing an exception.
  65             //  Eventually inter-procedural analysis should handle this easily.
  66             .Case("ziperr", true)
  67             .Case("assfail", true)
  68             .Case("db_error", true)
  69             .Case("__assert", true)
  70             .Case("__assert2", true)
  71             // For the purpose of static analysis, we do not care that
  72             //  this MSVC function will return if the user decides to continue.
  73             .Case("_wassert", true)
  74             .Case("__assert_rtn", true)
  75             .Case("__assert_fail", true)
  76             .Case("dtrace_assfail", true)
  77             .Case("yy_fatal_error", true)
  78             .Case("_XCAssertionFailureHandler", true)
  79             .Case("_DTAssertionFailureHandler", true)
  80             .Case("_TSAssertionFailureHandler", true)
  81             .Default(false);
  82     }
  83   }
  84
  85   if (BuildSinks)
  86     C.generateSink(C.getState(), C.getPredecessor());
  87 }
  88
  89 void NoReturnFunctionChecker::checkPostObjCMessage(const ObjCMethodCall &Msg,
  90                                                    CheckerContext &C) const {
  91   // Check if the method is annotated with analyzer_noreturn.
  92   if (const ObjCMethodDecl *MD = Msg.getDecl()) {
  93     MD = MD->getCanonicalDecl();
  94     if (MD->hasAttr<AnalyzerNoReturnAttr>()) {
  95       C.generateSink(C.getState(), C.getPredecessor());
  96       return;
  97     }
  98   }
  99
 100   // HACK: This entire check is to handle two messages in the Cocoa frameworks:
 101   // -[NSAssertionHandler
 102   //    handleFailureInMethod:object:file:lineNumber:description:]
 103   // -[NSAssertionHandler
 104   //    handleFailureInFunction:file:lineNumber:description:]
 105   // Eventually these should be annotated with __attribute__((noreturn)).
 106   // Because ObjC messages use dynamic dispatch, it is not generally safe to
 107   // assume certain methods can't return. In cases where it is definitely valid,
 108   // see if you can mark the methods noreturn or analyzer_noreturn instead of
 109   // adding more explicit checks to this method.
 110
 111   if (!Msg.isInstanceMessage())
 112     return;
 113
 114   const ObjCInterfaceDecl *Receiver = Msg.getReceiverInterface();
 115   if (!Receiver)
 116     return;
 117   if (!Receiver->getIdentifier()->isStr("NSAssertionHandler"))
 118     return;
 119
 120   Selector Sel = Msg.getSelector();
 121   switch (Sel.getNumArgs()) {
 122   default:
 123     return;
 124   case 4:
 125     lazyInitKeywordSelector(HandleFailureInFunctionSel, C.getASTContext(),
 126                             "handleFailureInFunction", "file", "lineNumber",
 127                             "description");
 128     if (Sel != HandleFailureInFunctionSel)
 129       return;
 130     break;
 131   case 5:
 132     lazyInitKeywordSelector(HandleFailureInMethodSel, C.getASTContext(),
 133                             "handleFailureInMethod", "object", "file",
 134                             "lineNumber", "description");
 135     if (Sel != HandleFailureInMethodSel)
 136       return;
 137     break;
 138   }
 139
 140   // If we got here, it's one of the messages we care about.
 141   C.generateSink(C.getState(), C.getPredecessor());
 142 }
 143
 144 void ento::registerNoReturnFunctionChecker(CheckerManager &mgr) {
 145   mgr.registerChecker<NoReturnFunctionChecker>();
 146 }
 147
 148 bool ento::shouldRegisterNoReturnFunctionChecker(const CheckerManager &mgr) {
 149   return true;
 150 }