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//=== NoReturnFunctionChecker.cpp -------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This defines NoReturnFunctionChecker, which evaluates functions that do not
// return to the caller.
//
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
#include "clang/AST/Attr.h"
#include "clang/Analysis/SelectorExtras.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "llvm/ADT/StringSwitch.h"
#include <cstdarg>
using namespace clang;
using namespace ento;
namespace {
class NoReturnFunctionChecker : public Checker< check::PostCall,
check::PostObjCMessage > {
mutable Selector HandleFailureInFunctionSel;
mutable Selector HandleFailureInMethodSel;
public:
void checkPostCall(const CallEvent &CE, CheckerContext &C) const;
void checkPostObjCMessage(const ObjCMethodCall &msg, CheckerContext &C) const;
};
}
void NoReturnFunctionChecker::checkPostCall(const CallEvent &CE,
CheckerContext &C) const {
bool BuildSinks = false;
if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(CE.getDecl()))
BuildSinks = FD->hasAttr<AnalyzerNoReturnAttr>() || FD->isNoReturn();
const Expr *Callee = CE.getOriginExpr();
if (!BuildSinks && Callee)
BuildSinks = getFunctionExtInfo(Callee->getType()).getNoReturn();
if (!BuildSinks && CE.isGlobalCFunction()) {
if (const IdentifierInfo *II = CE.getCalleeIdentifier()) {
// HACK: Some functions are not marked noreturn, and don't return.
// Here are a few hardwired ones. If this takes too long, we can
// potentially cache these results.
BuildSinks
= llvm::StringSwitch<bool>(StringRef(II->getName()))
.Case("exit", true)
.Case("panic", true)
.Case("error", true)
.Case("Assert", true)
// FIXME: This is just a wrapper around throwing an exception.
// Eventually inter-procedural analysis should handle this easily.
.Case("ziperr", true)
.Case("assfail", true)
.Case("db_error", true)
.Case("__assert", true)
.Case("__assert2", true)
// For the purpose of static analysis, we do not care that
// this MSVC function will return if the user decides to continue.
.Case("_wassert", true)
.Case("__assert_rtn", true)
.Case("__assert_fail", true)
.Case("dtrace_assfail", true)
.Case("yy_fatal_error", true)
.Case("_XCAssertionFailureHandler", true)
.Case("_DTAssertionFailureHandler", true)
.Case("_TSAssertionFailureHandler", true)
.Default(false);
}
}
if (BuildSinks)
C.generateSink(C.getState(), C.getPredecessor());
}
void NoReturnFunctionChecker::checkPostObjCMessage(const ObjCMethodCall &Msg,
CheckerContext &C) const {
// Check if the method is annotated with analyzer_noreturn.
if (const ObjCMethodDecl *MD = Msg.getDecl()) {
MD = MD->getCanonicalDecl();
if (MD->hasAttr<AnalyzerNoReturnAttr>()) {
C.generateSink(C.getState(), C.getPredecessor());
return;
}
}
// HACK: This entire check is to handle two messages in the Cocoa frameworks:
// -[NSAssertionHandler
// handleFailureInMethod:object:file:lineNumber:description:]
// -[NSAssertionHandler
// handleFailureInFunction:file:lineNumber:description:]
// Eventually these should be annotated with __attribute__((noreturn)).
// Because ObjC messages use dynamic dispatch, it is not generally safe to
// assume certain methods can't return. In cases where it is definitely valid,
// see if you can mark the methods noreturn or analyzer_noreturn instead of
// adding more explicit checks to this method.
if (!Msg.isInstanceMessage())
return;
const ObjCInterfaceDecl *Receiver = Msg.getReceiverInterface();
if (!Receiver)
return;
if (!Receiver->getIdentifier()->isStr("NSAssertionHandler"))
return;
Selector Sel = Msg.getSelector();
switch (Sel.getNumArgs()) {
default:
return;
case 4:
lazyInitKeywordSelector(HandleFailureInFunctionSel, C.getASTContext(),
"handleFailureInFunction", "file", "lineNumber",
"description");
if (Sel != HandleFailureInFunctionSel)
return;
break;
case 5:
lazyInitKeywordSelector(HandleFailureInMethodSel, C.getASTContext(),
"handleFailureInMethod", "object", "file",
"lineNumber", "description");
if (Sel != HandleFailureInMethodSel)
return;
break;
}
// If we got here, it's one of the messages we care about.
C.generateSink(C.getState(), C.getPredecessor());
}
void ento::registerNoReturnFunctionChecker(CheckerManager &mgr) {
mgr.registerChecker<NoReturnFunctionChecker>();
}
bool ento::shouldRegisterNoReturnFunctionChecker(const CheckerManager &mgr) {
return true;
}
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