//=== 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 "llvm/ADT/StringSwitch.h"

using namespace clang;
using namespace ento;

namespace {

class NoReturnFunctionChecker : public Checker< check::PostStmt<CallExpr> > {
public:
  void checkPostStmt(const CallExpr *CE, CheckerContext &C) const;
};

}

void NoReturnFunctionChecker::checkPostStmt(const CallExpr *CE,
                                            CheckerContext &C) const {
  const GRState *state = C.getState();
  const Expr *Callee = CE->getCallee();

  bool BuildSinks = getFunctionExtInfo(Callee->getType()).getNoReturn();

  if (!BuildSinks) {
    SVal L = state->getSVal(Callee);
    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>(llvm::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(CE);
}

void ento::registerNoReturnFunctionChecker(CheckerManager &mgr) {
  mgr.registerChecker<NoReturnFunctionChecker>();
}