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//=== NoReturnFunctionChecker.cpp -------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This defines NoReturnFunctionChecker, which evaluates functions that do not
// return to the caller.
//
//===----------------------------------------------------------------------===//
#include "ClangSACheckers.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ObjCMessage.h"
#include "llvm/ADT/StringSwitch.h"
#include <cstdarg>
using namespace clang;
using namespace ento;
namespace {
class NoReturnFunctionChecker : public Checker< check::PostStmt<CallExpr>,
check::PostObjCMessage > {
public:
void checkPostStmt(const CallExpr *CE, CheckerContext &C) const;
void checkPostObjCMessage(const ObjCMessage &msg, CheckerContext &C) const;
};
}
void NoReturnFunctionChecker::checkPostStmt(const CallExpr *CE,
CheckerContext &C) const {
ProgramStateRef state = C.getState();
const Expr *Callee = CE->getCallee();
bool BuildSinks = getFunctionExtInfo(Callee->getType()).getNoReturn();
if (!BuildSinks) {
SVal L = state->getSVal(Callee, C.getLocationContext());
const FunctionDecl *FD = L.getAsFunctionDecl();
if (!FD)
return;
if (FD->getAttr<AnalyzerNoReturnAttr>())
BuildSinks = true;
else if (const IdentifierInfo *II = FD->getIdentifier()) {
// 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("__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();
}
static bool END_WITH_NULL isMultiArgSelector(const Selector *Sel, ...) {
va_list argp;
va_start(argp, Sel);
unsigned Slot = 0;
const char *Arg;
while ((Arg = va_arg(argp, const char *))) {
if (!Sel->getNameForSlot(Slot).equals(Arg))
break; // still need to va_end!
++Slot;
}
va_end(argp);
// We only succeeded if we made it to the end of the argument list.
return (Arg == NULL);
}
void NoReturnFunctionChecker::checkPostObjCMessage(const ObjCMessage &Msg,
CheckerContext &C) const {
// 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:
if (!isMultiArgSelector(&Sel, "handleFailureInFunction", "file",
"lineNumber", "description", NULL))
return;
break;
case 5:
if (!isMultiArgSelector(&Sel, "handleFailureInMethod", "object", "file",
"lineNumber", "description", NULL))
return;
break;
}
// If we got here, it's one of the messages we care about.
C.generateSink();
}
void ento::registerNoReturnFunctionChecker(CheckerManager &mgr) {
mgr.registerChecker<NoReturnFunctionChecker>();
}
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