C++ DSGraph::getGlobalsGraph方法代码示例

//
// Method: getDSNodeHandle()
//
// Description:
//  This method looks up the DSNodeHandle for a given LLVM value.  The context
//  of the value is the specified function, although if it is a global value,
//  the DSNodeHandle may exist within the global DSGraph.
//
// Return value:
//  A DSNodeHandle for the value is returned.  This DSNodeHandle could either
//  be in the function's DSGraph or from the GlobalsGraph.  Note that the
//  DSNodeHandle may represent a NULL DSNode.
//
DSNodeHandle
CompleteChecks::getDSNodeHandle (const Value * V, const Function * F) {
  //
  // Get access to the points-to results.
  //
  EQTDDataStructures & dsaPass = getAnalysis<EQTDDataStructures>();

  //
  // Ensure that the function has a DSGraph
  //
  assert (dsaPass.hasDSGraph(*F) && "No DSGraph for function!\n");

  //
  // Lookup the DSNode for the value in the function's DSGraph.
  //
  DSGraph * TDG = dsaPass.getDSGraph(*F);
  DSNodeHandle DSH = TDG->getNodeForValue(V);

  //
  // If the value wasn't found in the function's DSGraph, then maybe we can
  // find the value in the globals graph.
  //
  if ((DSH.isNull()) && (isa<GlobalValue>(V))) {
    //
    // Try looking up this DSNode value in the globals graph.  Note that
    // globals are put into equivalence classes; we may need to first find the
    // equivalence class to which our global belongs, find the global that
    // represents all globals in that equivalence class, and then look up the
    // DSNode Handle for *that* global.
    //
    DSGraph * GlobalsGraph = TDG->getGlobalsGraph ();
    DSH = GlobalsGraph->getNodeForValue(V);
    if (DSH.isNull()) {
      //
      // DSA does not currently handle global aliases.
      //
      if (!isa<GlobalAlias>(V)) {
        //
        // We have to dig into the globalEC of the DSGraph to find the DSNode.
        //
        const GlobalValue * GV = dyn_cast<GlobalValue>(V);
        const GlobalValue * Leader;
        Leader = GlobalsGraph->getGlobalECs().getLeaderValue(GV);
        DSH = GlobalsGraph->getNodeForValue(Leader);
      }
    }
  }

  return DSH;
}

bool BUDataStructures::runOnModuleInternal(Module& M) {
  std::vector<const Function*> Stack;
  hash_map<const Function*, unsigned> ValMap;
  unsigned NextID = 1;

  Function *MainFunc = M.getFunction("main");
  if (MainFunc && !MainFunc->isDeclaration()) {
    calculateGraphs(MainFunc, Stack, NextID, ValMap);
    CloneAuxIntoGlobal(getDSGraph(MainFunc));
  } else {
    DEBUG(errs() << debugname << ": No 'main' function found!\n");
  }

  // Calculate the graphs for any functions that are unreachable from main...
  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
    if (!I->isDeclaration() && !hasDSGraph(I)) {
      if (MainFunc)
        DEBUG(errs() << debugname << ": Function unreachable from main: "
	      << I->getName() << "\n");
      calculateGraphs(I, Stack, NextID, ValMap);     // Calculate all graphs.
      CloneAuxIntoGlobal(getDSGraph(I));
    }

  // If we computed any temporary indcallgraphs, free them now.
  for (std::map<std::vector<const Function*>,
         std::pair<DSGraph*, std::vector<DSNodeHandle> > >::iterator I =
         IndCallGraphMap.begin(), E = IndCallGraphMap.end(); I != E; ++I) {
    I->second.second.clear();  // Drop arg refs into the graph.
    delete I->second.first;
  }
  IndCallGraphMap.clear();

  // At the end of the bottom-up pass, the globals graph becomes complete.
  // FIXME: This is not the right way to do this, but it is sorta better than
  // nothing!  In particular, externally visible globals and unresolvable call
  // nodes at the end of the BU phase should make things that they point to
  // incomplete in the globals graph.
  //

  finalizeGlobals();

  GlobalsGraph->removeTriviallyDeadNodes(true);
  GlobalsGraph->maskIncompleteMarkers();

  // Mark external globals incomplete.
  GlobalsGraph->markIncompleteNodes(DSGraph::IgnoreGlobals);

  formGlobalECs();

  // Merge the globals variables (not the calls) from the globals graph back
  // into the main function's graph so that the main function contains all of
  // the information about global pools and GV usage in the program.
  if (MainFunc && !MainFunc->isDeclaration()) {
    DSGraph* MainGraph = getDSGraph(MainFunc);
    const DSGraph* GG = MainGraph->getGlobalsGraph();
    ReachabilityCloner RC(MainGraph, GG,
                          DSGraph::DontCloneCallNodes |
                          DSGraph::DontCloneAuxCallNodes);

    // Clone the global nodes into this graph.
    for (DSScalarMap::global_iterator I = GG->getScalarMap().global_begin(),
           E = GG->getScalarMap().global_end(); I != E; ++I)
      if (isa<GlobalVariable>(*I))
        RC.getClonedNH(GG->getNodeForValue(*I));

    MainGraph->maskIncompleteMarkers();
    MainGraph->markIncompleteNodes(DSGraph::MarkFormalArgs |
                                   DSGraph::IgnoreGlobals);
  }

  NumCallEdges += callee.size();

  return false;
}