C++ ExprEngine类代码示例

void ento::RegisterAppleChecks(ExprEngine& Eng, const Decl &D) {
  Eng.registerCheck(new NilArgChecker());
  Eng.registerCheck(new CFNumberCreateChecker());
  RegisterNSErrorChecks(Eng.getBugReporter(), Eng, D);
  RegisterNSAutoreleasePoolChecks(Eng);
  Eng.registerCheck(new CFRetainReleaseChecker());
  Eng.registerCheck(new ClassReleaseChecker());
}

void UndefBranchChecker::checkBranchCondition(const Stmt *Condition,
                                              BranchNodeBuilder &Builder,
                                              ExprEngine &Eng) const {
  const GRState *state = Builder.getState();
  SVal X = state->getSVal(Condition);
  if (X.isUndef()) {
    ExplodedNode *N = Builder.generateNode(state, true);
    if (N) {
      N->markAsSink();
      if (!BT)
        BT.reset(
               new BuiltinBug("Branch condition evaluates to a garbage value"));

      // What's going on here: we want to highlight the subexpression of the
      // condition that is the most likely source of the "uninitialized
      // branch condition."  We do a recursive walk of the condition's
      // subexpressions and roughly look for the most nested subexpression
      // that binds to Undefined.  We then highlight that expression's range.
      BlockEdge B = cast<BlockEdge>(N->getLocation());
      const Expr* Ex = cast<Expr>(B.getSrc()->getTerminatorCondition());
      assert (Ex && "Block must have a terminator.");

      // Get the predecessor node and check if is a PostStmt with the Stmt
      // being the terminator condition.  We want to inspect the state
      // of that node instead because it will contain main information about
      // the subexpressions.
      assert (!N->pred_empty());

      // Note: any predecessor will do.  They should have identical state,
      // since all the BlockEdge did was act as an error sink since the value
      // had to already be undefined.
      ExplodedNode *PrevN = *N->pred_begin();
      ProgramPoint P = PrevN->getLocation();
      const GRState* St = N->getState();

      if (PostStmt* PS = dyn_cast<PostStmt>(&P))
        if (PS->getStmt() == Ex)
          St = PrevN->getState();

      FindUndefExpr FindIt(Eng.getStateManager(), St);
      Ex = FindIt.FindExpr(Ex);

      // Emit the bug report.
      EnhancedBugReport *R = new EnhancedBugReport(*BT, BT->getDescription(),N);
      R->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, Ex);
      R->addRange(Ex->getSourceRange());

      Eng.getBugReporter().EmitReport(R);
    }

    Builder.markInfeasible(true);
    Builder.markInfeasible(false);
  }
}

/// \brief Run checkers for evaluating a call.
/// Only one checker will evaluate the call.
void CheckerManager::runCheckersForEvalCall(ExplodedNodeSet &Dst,
                                            const ExplodedNodeSet &Src,
                                            const CallEvent &Call,
                                            ExprEngine &Eng) {
  const CallExpr *CE = cast<CallExpr>(Call.getOriginExpr());
  for (ExplodedNodeSet::iterator
         NI = Src.begin(), NE = Src.end(); NI != NE; ++NI) {
    ExplodedNode *Pred = *NI;
    bool anyEvaluated = false;

    ExplodedNodeSet checkDst;
    NodeBuilder B(Pred, checkDst, Eng.getBuilderContext());

    // Check if any of the EvalCall callbacks can evaluate the call.
    for (std::vector<EvalCallFunc>::iterator
           EI = EvalCallCheckers.begin(), EE = EvalCallCheckers.end();
         EI != EE; ++EI) {
      ProgramPoint::Kind K = ProgramPoint::PostStmtKind;
      const ProgramPoint &L = ProgramPoint::getProgramPoint(CE, K,
                                Pred->getLocationContext(), EI->Checker);
      bool evaluated = false;
      { // CheckerContext generates transitions(populates checkDest) on
        // destruction, so introduce the scope to make sure it gets properly
        // populated.
        CheckerContext C(B, Eng, Pred, L);
        evaluated = (*EI)(CE, C);
      }
      assert(!(evaluated && anyEvaluated)
             && "There are more than one checkers evaluating the call");
      if (evaluated) {
        anyEvaluated = true;
        Dst.insert(checkDst);
#ifdef NDEBUG
        break; // on release don't check that no other checker also evals.
#endif
      }
    }
    
    // If none of the checkers evaluated the call, ask ExprEngine to handle it.
    if (!anyEvaluated) {
      NodeBuilder B(Pred, Dst, Eng.getBuilderContext());
      Eng.defaultEvalCall(B, Pred, Call);
    }
  }
}

void MallocChecker::checkEndPath(EndOfFunctionNodeBuilder &B,
                                 ExprEngine &Eng) const {
  const GRState *state = B.getState();
  RegionStateTy M = state->get<RegionState>();

  for (RegionStateTy::iterator I = M.begin(), E = M.end(); I != E; ++I) {
    RefState RS = I->second;
    if (RS.isAllocated()) {
      ExplodedNode *N = B.generateNode(state);
      if (N) {
        if (!BT_Leak)
          BT_Leak.reset(new BuiltinBug("Memory leak",
                    "Allocated memory never released. Potential memory leak."));
        BugReport *R = new BugReport(*BT_Leak, BT_Leak->getDescription(), N);
        Eng.getBugReporter().EmitReport(R);
      }
    }
  }
}

/// \brief Run checkers for evaluating a call.
/// Only one checker will evaluate the call.
void CheckerManager::runCheckersForEvalCall(ExplodedNodeSet &Dst,
                                            const ExplodedNodeSet &Src,
                                            const CallExpr *CE,
                                            ExprEngine &Eng,
                                            GraphExpander *defaultEval) {
  if (EvalCallCheckers.empty() && defaultEval == 0) {
    Dst.insert(Src);
    return;
  }

  for (ExplodedNodeSet::iterator
         NI = Src.begin(), NE = Src.end(); NI != NE; ++NI) {

    ExplodedNode *Pred = *NI;
    bool anyEvaluated = false;
    for (std::vector<EvalCallFunc>::iterator
           EI = EvalCallCheckers.begin(), EE = EvalCallCheckers.end();
         EI != EE; ++EI) {
      ExplodedNodeSet checkDst;
      CheckerContext C(checkDst, Eng.getBuilder(), Eng, Pred, EI->Checker,
                       ProgramPoint::PostStmtKind, 0, CE);
      bool evaluated = (*EI)(CE, C);
      assert(!(evaluated && anyEvaluated)
             && "There are more than one checkers evaluating the call");
      if (evaluated) {
        anyEvaluated = true;
        Dst.insert(checkDst);
#ifdef NDEBUG
        break; // on release don't check that no other checker also evals.
#endif
      }
    }
    
    if (!anyEvaluated) {
      if (defaultEval)
        defaultEval->expandGraph(Dst, Pred);
      else
        Dst.insert(Pred);
    }
  }
}

void AnalyzerStatsChecker::checkEndAnalysis(ExplodedGraph &G,
                                            BugReporter &B,
                                            ExprEngine &Eng) const {
  const CFG *C  = 0;
  const SourceManager &SM = B.getSourceManager();
  llvm::SmallPtrSet<const CFGBlock*, 256> reachable;

  // Root node should have the location context of the top most function.
  const ExplodedNode *GraphRoot = *G.roots_begin();
  const LocationContext *LC = GraphRoot->getLocation().getLocationContext();

  const Decl *D = LC->getDecl();

  // Iterate over the exploded graph.
  for (ExplodedGraph::node_iterator I = G.nodes_begin();
      I != G.nodes_end(); ++I) {
    const ProgramPoint &P = I->getLocation();

    // Only check the coverage in the top level function (optimization).
    if (D != P.getLocationContext()->getDecl())
      continue;

    if (const BlockEntrance *BE = dyn_cast<BlockEntrance>(&P)) {
      const CFGBlock *CB = BE->getBlock();
      reachable.insert(CB);
    }
  }

  // Get the CFG and the Decl of this block.
  C = LC->getCFG();

  unsigned total = 0, unreachable = 0;

  // Find CFGBlocks that were not covered by any node
  for (CFG::const_iterator I = C->begin(); I != C->end(); ++I) {
    const CFGBlock *CB = *I;
    ++total;
    // Check if the block is unreachable
    if (!reachable.count(CB)) {
      ++unreachable;
    }
  }

  // We never 'reach' the entry block, so correct the unreachable count
  unreachable--;
  // There is no BlockEntrance corresponding to the exit block as well, so
  // assume it is reached as well.
  unreachable--;

  // Generate the warning string
  SmallString<128> buf;
  llvm::raw_svector_ostream output(buf);
  PresumedLoc Loc = SM.getPresumedLoc(D->getLocation());
  if (!Loc.isValid())
    return;

  if (isa<FunctionDecl>(D) || isa<ObjCMethodDecl>(D)) {
    const NamedDecl *ND = cast<NamedDecl>(D);
    output << *ND;
  }
  else if (isa<BlockDecl>(D)) {
    output << "block(line:" << Loc.getLine() << ":col:" << Loc.getColumn();
  }

  NumBlocksUnreachable += unreachable;
  NumBlocks += total;
  std::string NameOfRootFunction = output.str();

  output << " -> Total CFGBlocks: " << total << " | Unreachable CFGBlocks: "
      << unreachable << " | Exhausted Block: "
      << (Eng.wasBlocksExhausted() ? "yes" : "no")
      << " | Empty WorkList: "
      << (Eng.hasEmptyWorkList() ? "yes" : "no");

  B.EmitBasicReport(D, "Analyzer Statistics", "Internal Statistics",
                    output.str(), PathDiagnosticLocation(D, SM));

  // Emit warning for each block we bailed out on.
  typedef CoreEngine::BlocksExhausted::const_iterator ExhaustedIterator;
  const CoreEngine &CE = Eng.getCoreEngine();
  for (ExhaustedIterator I = CE.blocks_exhausted_begin(),
      E = CE.blocks_exhausted_end(); I != E; ++I) {
    const BlockEdge &BE =  I->first;
    const CFGBlock *Exit = BE.getDst();
    const CFGElement &CE = Exit->front();
    if (const CFGStmt *CS = dyn_cast<CFGStmt>(&CE)) {
      SmallString<128> bufI;
      llvm::raw_svector_ostream outputI(bufI);
      outputI << "(" << NameOfRootFunction << ")" <<
                 ": The analyzer generated a sink at this point";
      B.EmitBasicReport(D, "Sink Point", "Internal Statistics", outputI.str(),
                        PathDiagnosticLocation::createBegin(CS->getStmt(),
                                                            SM, LC));
    }
  }
}

void ento::RegisterOSAtomicChecker(ExprEngine &Eng) {
  Eng.registerCheck(new OSAtomicChecker());
}

void UnreachableCodeChecker::checkEndAnalysis(ExplodedGraph &G,
                                              BugReporter &B,
                                              ExprEngine &Eng) const {
  CFGBlocksSet reachable, visited;

  if (Eng.hasWorkRemaining())
    return;

  const Decl *D = nullptr;
  CFG *C = nullptr;
  ParentMap *PM = nullptr;
  const LocationContext *LC = nullptr;
  // Iterate over ExplodedGraph
  for (ExplodedGraph::node_iterator I = G.nodes_begin(), E = G.nodes_end();
      I != E; ++I) {
    const ProgramPoint &P = I->getLocation();
    LC = P.getLocationContext();
    if (!LC->inTopFrame())
      continue;

    if (!D)
      D = LC->getAnalysisDeclContext()->getDecl();

    // Save the CFG if we don't have it already
    if (!C)
      C = LC->getAnalysisDeclContext()->getUnoptimizedCFG();
    if (!PM)
      PM = &LC->getParentMap();

    if (Optional<BlockEntrance> BE = P.getAs<BlockEntrance>()) {
      const CFGBlock *CB = BE->getBlock();
      reachable.insert(CB->getBlockID());
    }
  }

  // Bail out if we didn't get the CFG or the ParentMap.
  if (!D || !C || !PM)
    return;

  // Don't do anything for template instantiations.  Proving that code
  // in a template instantiation is unreachable means proving that it is
  // unreachable in all instantiations.
  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
    if (FD->isTemplateInstantiation())
      return;

  // Find CFGBlocks that were not covered by any node
  for (CFG::const_iterator I = C->begin(), E = C->end(); I != E; ++I) {
    const CFGBlock *CB = *I;
    // Check if the block is unreachable
    if (reachable.count(CB->getBlockID()))
      continue;

    // Check if the block is empty (an artificial block)
    if (isEmptyCFGBlock(CB))
      continue;

    // Find the entry points for this block
    if (!visited.count(CB->getBlockID()))
      FindUnreachableEntryPoints(CB, reachable, visited);

    // This block may have been pruned; check if we still want to report it
    if (reachable.count(CB->getBlockID()))
      continue;

    // Check for false positives
    if (isInvalidPath(CB, *PM))
      continue;

    // It is good practice to always have a "default" label in a "switch", even
    // if we should never get there. It can be used to detect errors, for
    // instance. Unreachable code directly under a "default" label is therefore
    // likely to be a false positive.
    if (const Stmt *label = CB->getLabel())
      if (label->getStmtClass() == Stmt::DefaultStmtClass)
        continue;

    // Special case for __builtin_unreachable.
    // FIXME: This should be extended to include other unreachable markers,
    // such as llvm_unreachable.
    if (!CB->empty()) {
      bool foundUnreachable = false;
      for (CFGBlock::const_iterator ci = CB->begin(), ce = CB->end();
           ci != ce; ++ci) {
        if (Optional<CFGStmt> S = (*ci).getAs<CFGStmt>())
          if (const CallExpr *CE = dyn_cast<CallExpr>(S->getStmt())) {
            if (CE->getBuiltinCallee() == Builtin::BI__builtin_unreachable ||
                CE->isBuiltinAssumeFalse(Eng.getContext())) {
              foundUnreachable = true;
              break;
            }
          }
      }
      if (foundUnreachable)
        continue;
    }

    // We found a block that wasn't covered - find the statement to report
    SourceRange SR;
    PathDiagnosticLocation DL;
//.........这里部分代码省略.........

/// \brief Run checkers for evaluating a call.
/// Only one checker will evaluate the call.
void CheckerManager::runCheckersForEvalCall(ExplodedNodeSet &Dst,
                                            const ExplodedNodeSet &Src,
                                            const CallExpr *CE,
                                            ExprEngine &Eng,
                                            GraphExpander *defaultEval) {
  if (EvalCallCheckers.empty()   &&
      InlineCallCheckers.empty() &&
      defaultEval == 0) {
    Dst.insert(Src);
    return;
  }

  for (ExplodedNodeSet::iterator
         NI = Src.begin(), NE = Src.end(); NI != NE; ++NI) {

    ExplodedNode *Pred = *NI;
    bool anyEvaluated = false;

    // First, check if any of the InlineCall callbacks can evaluate the call.
    assert(InlineCallCheckers.size() <= 1 &&
           "InlineCall is a special hacky callback to allow intrusive"
           "evaluation of the call (which simulates inlining). It is "
           "currently only used by OSAtomicChecker and should go away "
           "at some point.");
    for (std::vector<InlineCallFunc>::iterator
           EI = InlineCallCheckers.begin(), EE = InlineCallCheckers.end();
         EI != EE; ++EI) {
      ExplodedNodeSet checkDst;
      bool evaluated = (*EI)(CE, Eng, Pred, checkDst);
      assert(!(evaluated && anyEvaluated)
             && "There are more than one checkers evaluating the call");
      if (evaluated) {
        anyEvaluated = true;
        Dst.insert(checkDst);
#ifdef NDEBUG
        break; // on release don't check that no other checker also evals.
#endif
      }
    }

#ifdef NDEBUG // on release don't check that no other checker also evals.
    if (anyEvaluated) {
      break;
    }
#endif

    // Next, check if any of the EvalCall callbacks can evaluate the call.
    for (std::vector<EvalCallFunc>::iterator
           EI = EvalCallCheckers.begin(), EE = EvalCallCheckers.end();
         EI != EE; ++EI) {
      ExplodedNodeSet checkDst;
      ProgramPoint::Kind K = ProgramPoint::PostStmtKind;
      const ProgramPoint &L = ProgramPoint::getProgramPoint(CE, K,
                                Pred->getLocationContext(), EI->Checker);
      bool evaluated = false;
      { // CheckerContext generates transitions(populates checkDest) on
        // destruction, so introduce the scope to make sure it gets properly
        // populated.
        CheckerContext C(checkDst, Eng.getBuilder(), Eng, Pred, L, 0);
        evaluated = (*EI)(CE, C);
      }
      assert(!(evaluated && anyEvaluated)
             && "There are more than one checkers evaluating the call");
      if (evaluated) {
        anyEvaluated = true;
        Dst.insert(checkDst);
#ifdef NDEBUG
        break; // on release don't check that no other checker also evals.
#endif
      }
    }
    
    // If none of the checkers evaluated the call, ask ExprEngine to handle it.
    if (!anyEvaluated) {
      if (defaultEval)
        defaultEval->expandGraph(Dst, Pred);
      else
        Dst.insert(Pred);
    }
  }
}

void ento::RegisterArrayBoundCheckerV2(ExprEngine &Eng) {
  Eng.registerCheck(new ArrayBoundCheckerV2());
}

void ento::RegisterDivZeroChecker(ExprEngine &Eng) {
  Eng.registerCheck(new DivZeroChecker());
}

void ento::RegisterPthreadLockChecker(ExprEngine &Eng) {
  Eng.registerCheck(new PthreadLockChecker());
}

void ento::RegisterVLASizeChecker(ExprEngine &Eng) {
  Eng.registerCheck(new VLASizeChecker());
}

void ento::RegisterIdempotentOperationChecker(ExprEngine &Eng) {
  Eng.registerCheck(new IdempotentOperationChecker());
}

void UnreachableCodeChecker::checkEndAnalysis(ExplodedGraph &G,
                                              BugReporter &B,
                                              ExprEngine &Eng) const {
  CFGBlocksSet reachable, visited;

  if (Eng.hasWorkRemaining())
    return;

  CFG *C = 0;
  ParentMap *PM = 0;
  // Iterate over ExplodedGraph
  for (ExplodedGraph::node_iterator I = G.nodes_begin(), E = G.nodes_end();
      I != E; ++I) {
    const ProgramPoint &P = I->getLocation();
    const LocationContext *LC = P.getLocationContext();

    // Save the CFG if we don't have it already
    if (!C)
      C = LC->getAnalysisContext()->getUnoptimizedCFG();
    if (!PM)
      PM = &LC->getParentMap();

    if (const BlockEntrance *BE = dyn_cast<BlockEntrance>(&P)) {
      const CFGBlock *CB = BE->getBlock();
      reachable.insert(CB->getBlockID());
    }
  }

  // Bail out if we didn't get the CFG or the ParentMap.
  if (!C || !PM)
    return;

  ASTContext &Ctx = B.getContext();

  // Find CFGBlocks that were not covered by any node
  for (CFG::const_iterator I = C->begin(), E = C->end(); I != E; ++I) {
    const CFGBlock *CB = *I;
    // Check if the block is unreachable
    if (reachable.count(CB->getBlockID()))
      continue;

    // Check if the block is empty (an artificial block)
    if (isEmptyCFGBlock(CB))
      continue;

    // Find the entry points for this block
    if (!visited.count(CB->getBlockID()))
      FindUnreachableEntryPoints(CB, reachable, visited);

    // This block may have been pruned; check if we still want to report it
    if (reachable.count(CB->getBlockID()))
      continue;

    // Check for false positives
    if (CB->size() > 0 && isInvalidPath(CB, *PM))
      continue;

    // Special case for __builtin_unreachable.
    // FIXME: This should be extended to include other unreachable markers,
    // such as llvm_unreachable.
    if (!CB->empty()) {
      CFGElement First = CB->front();
      if (const CFGStmt *S = First.getAs<CFGStmt>()) {
        if (const CallExpr *CE = dyn_cast<CallExpr>(S->getStmt())) {
          if (CE->isBuiltinCall(Ctx) == Builtin::BI__builtin_unreachable)
            continue;
        }
      }
    }

    // We found a block that wasn't covered - find the statement to report
    SourceRange SR;
    SourceLocation SL;
    if (const Stmt *S = getUnreachableStmt(CB)) {
      SR = S->getSourceRange();
      SL = S->getLocStart();
      if (SR.isInvalid() || SL.isInvalid())
        continue;
    }
    else
      continue;

    // Check if the SourceLocation is in a system header
    const SourceManager &SM = B.getSourceManager();
    if (SM.isInSystemHeader(SL) || SM.isInExternCSystemHeader(SL))
      continue;

    B.EmitBasicReport("Unreachable code", "Dead code", "This statement is never"
        " executed", SL, SR);
  }
}