C++ ExplodedGraph类代码示例

void ExplodedNode::NodeGroup::addNode(ExplodedNode *N, ExplodedGraph &G) {
  assert(!getFlag());

  GroupStorage &Storage = reinterpret_cast<GroupStorage&>(P);
  if (Storage.isNull()) {
    Storage = N;
    assert(Storage.is<ExplodedNode *>());
    return;
  }

  ExplodedNodeVector *V = Storage.dyn_cast<ExplodedNodeVector *>();

  if (!V) {
    // Switch from single-node to multi-node representation.
    ExplodedNode *Old = Storage.get<ExplodedNode *>();

    BumpVectorContext &Ctx = G.getNodeAllocator();
    V = G.getAllocator().Allocate<ExplodedNodeVector>();
    new (V) ExplodedNodeVector(Ctx, 4);
    V->push_back(Old, Ctx);

    Storage = V;
    assert(!getFlag());
    assert(Storage.is<ExplodedNodeVector *>());
  }

  V->push_back(N, G.getNodeAllocator());
}

void ExplodedNode::NodeGroup::addNode(ExplodedNode *N, ExplodedGraph &G) {
  assert((reinterpret_cast<uintptr_t>(N) & Mask) == 0x0);
  assert(!getFlag());

  if (getKind() == Size1) {
    if (ExplodedNode *NOld = getNode()) {
      BumpVectorContext &Ctx = G.getNodeAllocator();
      BumpVector<ExplodedNode*> *V = 
        G.getAllocator().Allocate<BumpVector<ExplodedNode*> >();
      new (V) BumpVector<ExplodedNode*>(Ctx, 4);
      
      assert((reinterpret_cast<uintptr_t>(V) & Mask) == 0x0);
      V->push_back(NOld, Ctx);
      V->push_back(N, Ctx);
      P = reinterpret_cast<uintptr_t>(V) | SizeOther;
      assert(getPtr() == (void*) V);
      assert(getKind() == SizeOther);
    }
    else {
      P = reinterpret_cast<uintptr_t>(N);
      assert(getKind() == Size1);
    }
  }
  else {
    assert(getKind() == SizeOther);
    getVector(getPtr()).push_back(N, G.getNodeAllocator());
  }
}

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.........

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);
  }
}

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));
    }
  }
}