C++ DSGraph::getGlobalECs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
SteensgaardDataStructures::runOnModuleInternal(Module &M) {
  assert(ResultGraph == 0 && "Result graph already allocated!");
  
  // Get a copy for the globals graph.
  DSGraph * GG = DS->getGlobalsGraph();
  GlobalsGraph = new DSGraph(GG, GG->getGlobalECs(), 0, 0);

  // Create a new, empty, graph...
  ResultGraph = new DSGraph(GG->getGlobalECs(), getDataLayout(), GlobalsGraph);
  
  // Loop over the rest of the module, merging graphs for non-external functions
  // into this graph.
  //
  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
    if (!I->isDeclaration()) {
      ResultGraph->spliceFrom(DS->getDSGraph(I));
    }
  }

  ResultGraph->removeTriviallyDeadNodes();

  // FIXME: Must recalculate and use the Incomplete markers!!

  // Now that we have all of the graphs inlined, we can go about eliminating
  // call nodes...
  //

  // Start with a copy of the original call sites.
  std::list<DSCallSite> & Calls = ResultGraph->getFunctionCalls();

  for (std::list<DSCallSite>::iterator CI = Calls.begin(), E = Calls.end();
       CI != E;) {
    DSCallSite &CurCall = *CI++;

    // Loop over the called functions, eliminating as many as possible...
    std::vector<const Function*> CallTargets;
    if (CurCall.isDirectCall())
      CallTargets.push_back(CurCall.getCalleeFunc());
    else
      CurCall.getCalleeNode()->addFullFunctionList(CallTargets);

    for (unsigned c = 0; c != CallTargets.size(); ) {
      // If we can eliminate this function call, do so!
      const Function *F = CallTargets[c];
      if (!F->isDeclaration()) {
        ResolveFunctionCall(F, CurCall, ResultGraph->getReturnNodes()[F]);
        CallTargets[c] = CallTargets.back();
        CallTargets.pop_back();
      } else
        ++c;  // Cannot eliminate this call, skip over it...
    }

    if (CallTargets.empty()) {        // Eliminated all calls?
      std::list<DSCallSite>::iterator I = CI;
      Calls.erase(--I);               // Remove entry
    }
  }

  // Remove our knowledge of what the return values of the functions are, except
  // for functions that are externally visible from this module (e.g. main).  We
  // keep these functions so that their arguments are marked incomplete.
  for (DSGraph::ReturnNodesTy::iterator I =
         ResultGraph->getReturnNodes().begin(),
         E = ResultGraph->getReturnNodes().end(); I != E; )
    if (I->first->hasInternalLinkage())
      ResultGraph->getReturnNodes().erase(I++);
    else
      ++I;

  // Update the "incomplete" markers on the nodes, ignoring unknownness due to
  // incoming arguments...
  ResultGraph->maskIncompleteMarkers();

  ResultGraph->markIncompleteNodes(DSGraph::MarkFormalArgs | DSGraph::IgnoreGlobals);

  // Remove any nodes that are dead after all of the merging we have done...

  ResultGraph->removeDeadNodes(DSGraph::KeepUnreachableGlobals);

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

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

  formGlobalECs();

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

  print(DOUT, &M);
  return false;
//.........这里部分代码省略.........

void RTAssociate::replaceCall(CallSite CS, FuncInfo& FI, DataStructures* DS) {
  const Function *CF = CS.getCalledFunction();
  Instruction *TheCall = CS.getInstruction();

  // If the called function is casted from one function type to another, peer
  // into the cast instruction and pull out the actual function being called.
  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(CS.getCalledValue()))
    if (CE->getOpcode() == Instruction::BitCast &&
        isa<Function>(CE->getOperand(0)))
      CF = cast<Function>(CE->getOperand(0));

  if (isa<InlineAsm>(TheCall->getOperand(0))) {
    errs() << "INLINE ASM: ignoring.  Hoping that's safe.\n";
    return;
  }

  // Ignore calls to NULL pointers.
  if (isa<ConstantPointerNull>(CS.getCalledValue())) {
    errs() << "WARNING: Ignoring call using NULL function pointer.\n";
    return;
  }
  // We need to figure out which local pool descriptors correspond to the pool
  // descriptor arguments passed into the function call.  Calculate a mapping
  // from callee DSNodes to caller DSNodes.  We construct a partial isomophism
  // between the graphs to figure out which pool descriptors need to be passed
  // in.  The roots of this mapping is found from arguments and return values.
  //
  DSGraph::NodeMapTy NodeMapping;
  Instruction *NewCall;
  Value *NewCallee;
  std::vector<const DSNode*> ArgNodes;
  DSGraph *CalleeGraph;  // The callee graph

  // For indirect callees, find any callee since all DS graphs have been
  // merged.
  if (CF) { // Direct calls are nice and simple.
    DEBUG(errs() << "  Handling direct call: " << *TheCall);
    FuncInfo *CFI = getFuncInfo(CF);
    if (CFI == 0 || CFI->Clone == 0) // Nothing to transform...
      return;

    NewCallee = CFI->Clone;
    ArgNodes = CFI->ArgNodes;

    assert ((DS->hasDSGraph (*CF)) && "Function has no ECGraph!\n");
    CalleeGraph = DS->getDSGraph(*CF);
  } else {
    DEBUG(errs() << "  Handling indirect call: " << *TheCall);

    // Here we fill in CF with one of the possible called functions.  Because we
    // merged together all of the arguments to all of the functions in the
    // equivalence set, it doesn't really matter which one we pick.
    // (If the function was cloned, we have to map the cloned call instruction
    // in CS back to the original call instruction.)
    Instruction *OrigInst =
      cast<Instruction>(FI.getOldValueIfAvailable(CS.getInstruction()));

    DSCallGraph::callee_iterator I = DS->getCallGraph().callee_begin(CS);
    if (I != DS->getCallGraph().callee_end(CS))
      CF = *I;

    // If we didn't find the callee in the constructed call graph, try
    // checking in the DSNode itself.
    // This isn't ideal as it means that this call site didn't have inlining
    // happen.
    if (!CF) {
      DSGraph* dg = DS->getDSGraph(*OrigInst->getParent()->getParent());
      DSNode* d = dg->getNodeForValue(OrigInst->getOperand(0)).getNode();
      assert (d && "No DSNode!\n");
      std::vector<const Function*> g;
      d->addFullFunctionList(g);
      if (g.size()) {
        EquivalenceClasses< const GlobalValue *> & EC = dg->getGlobalECs();
        for(std::vector<const Function*>::const_iterator ii = g.begin(), ee = g.end();
            !CF && ii != ee; ++ii) {
          for (EquivalenceClasses<const GlobalValue *>::member_iterator MI = EC.findLeader(*ii);
               MI != EC.member_end(); ++MI) // Loop over members in this set.
            if ((CF = dyn_cast<Function>(*MI))) {
              break;
            }
        }
      }
    }

    //
    // Do an assert unless we're bugpointing something.
    //
//    if ((UsingBugpoint) && (!CF)) return;
    if (!CF)
      errs() << "No Graph for CallSite in "
      << TheCall->getParent()->getParent()->getName().str()
      << " originally "
      << OrigInst->getParent()->getParent()->getName().str()
      << "\n";

    assert (CF && "No call graph info");

    // Get the common graph for the set of functions this call may invoke.
//    if (UsingBugpoint && (!(Graphs.hasDSGraph(*CF)))) return;
    assert ((DS->hasDSGraph(*CF)) && "Function has no DSGraph!\n");
//.........这里部分代码省略.........