C++ DSGraph::fc_begin方法代码示例

void TDDataStructures::ComputePostOrder(const Function* F,
                                        hash_set<DSGraph*> &Visited,
                                        std::vector<DSGraph*> &PostOrder) {
  if (F->isDeclaration()) return;
  DSGraph* G = getOrFetchDSGraph(F);
  if (Visited.count(G)) return;
  Visited.insert(G);

  // Recursively traverse all of the callee graphs.
  for (DSGraph::fc_iterator CI = G->fc_begin(), CE = G->fc_end(); CI != CE; ++CI){
    Instruction *CallI = CI->getCallSite().getInstruction();
    for (calleeTy::iterator I = callee.begin(CallI),
           E = callee.end(CallI); I != E; ++I)
      ComputePostOrder(*I, Visited, PostOrder);
  }

  PostOrder.push_back(G);
}

void TDDataStructures::ComputePostOrder(const Function &F,
                                        DenseSet<DSGraph*> &Visited,
                                        std::vector<DSGraph*> &PostOrder) {
  if (F.isDeclaration()) return;
  DSGraph* G = getOrCreateGraph(&F);
  if (!Visited.insert(G).second) return;

  // Recursively traverse all of the callee graphs.
  svset<const Function*> Callees;

  // Go through all of the callsites in this graph and find all callees
  // Here we're trying to capture all possible callees so that we can ensure
  // each function has all possible callers inlined into it.
  for (DSGraph::fc_iterator CI = G->fc_begin(), E = G->fc_end();
       CI != E; ++CI) {
    // Direct calls are easy, no reason to look at DSCallGraph
    // or anything to do with SCC's
    if (CI->isDirectCall()) {
      ComputePostOrder(*CI->getCalleeFunc(), Visited, PostOrder);
    }
    else {
      // Otherwise, ask the DSCallGraph for the full set of possible
      // callees for this callsite.
      // This includes all members of the SCC's of those callees,
      // and well as others in F's SCC, since we must assume
      // any indirect call might be intra-SCC.
      callgraph.addFullFunctionSet(CI->getCallSite(), Callees);
    }
  }

  for (svset<const Function*>::iterator I = Callees.begin(),
       E = Callees.end(); I != E; ++I)
    ComputePostOrder(**I, Visited, PostOrder);

  PostOrder.push_back(G);
}

/// visitGraph - Visit the functions in the specified graph, updating the
/// specified lattice values for all of their uses.
///
void StructureFieldVisitorBase::
visitGraph(DSGraph &DSG, std::multimap<DSNode*, LatticeValue*> &NodeLVs) {
  assert(!NodeLVs.empty() && "No lattice values to compute!");

  // To visit a graph, first step, we visit the instruction making up each
  // function in the graph, but ignore calls when processing them.  We handle
  // call nodes explicitly by looking at call nodes in the graph if needed.  We
  // handle instructions before calls to avoid interprocedural analysis if we
  // can drive lattice values to bottom early.
  //
  SFVInstVisitor IV(DSG, Callbacks, NodeLVs);

  for (DSGraph::retnodes_iterator FI = DSG.retnodes_begin(),
         E = DSG.retnodes_end(); FI != E; ++FI)
    for (Function::iterator BB = FI->first->begin(), E = FI->first->end();
         BB != E; ++BB)
      for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
        if (IV.visit(*I) && NodeLVs.empty())
          return;  // Nothing left to analyze.

  // Keep track of which actual direct callees are handled.
  std::set<Function*> CalleesHandled;

  // Once we have visited all of the instructions in the function bodies, if
  // there are lattice values that have not been driven to bottom, see if any of
  // the nodes involved are passed into function calls.  If so, we potentially
  // have to recursively traverse the call graph.
  for (DSGraph::fc_iterator CS = DSG.fc_begin(), E = DSG.fc_end();
       CS != E; ++CS) {
    // Figure out the mapping from a node in the caller (potentially several)
    // nodes in the callee.
    DSGraph::NodeMapTy CallNodeMap;

    Instruction *TheCall = CS->getCallSite().getInstruction();

    // If this is an indirect function call, assume nothing gets passed through
    // it. FIXME: THIS IS BROKEN!  Just get the ECG for the fn ptr if it's not
    // direct.
    if (CS->isIndirectCall())
      continue;

    // If this is an external function call, it cannot be involved with this
    // node, because otherwise the node would be marked incomplete!
    if (CS->getCalleeFunc()->isExternal())
      continue;

    // If we can handle this function call, remove it from the set of direct
    // calls found by the visitor.
    CalleesHandled.insert(CS->getCalleeFunc());

    std::vector<DSNodeHandle> Args;

    DSGraph *CG = &ECG.getDSGraph(*CS->getCalleeFunc());
    CG->getFunctionArgumentsForCall(CS->getCalleeFunc(), Args);

    if (!CS->getRetVal().isNull())
      DSGraph::computeNodeMapping(Args[0], CS->getRetVal(), CallNodeMap);
    for (unsigned i = 0, e = CS->getNumPtrArgs(); i != e; ++i) {
      if (i == Args.size()-1) break;
      DSGraph::computeNodeMapping(Args[i+1], CS->getPtrArg(i), CallNodeMap);
    }
    Args.clear();

    // The mapping we just computed maps from nodes in the callee to nodes in
    // the caller, so we can't query it efficiently.  Instead of going through
    // the trouble of inverting the map to do this (linear time with the size of
    // the mapping), we just do a linear search to see if any affected nodes are
    // passed into this call.
    bool CallCanModifyDataFlow = false;
    for (DSGraph::NodeMapTy::iterator MI = CallNodeMap.begin(),
           E = CallNodeMap.end(); MI != E; ++MI)
      if (NodeLVs.count(MI->second.getNode()))
        // Okay, the node is passed in, check to see if the call might do
        // something interesting to it (i.e. if analyzing the call can produce
        // anything other than "top").
        if ((CallCanModifyDataFlow = NodeCanPossiblyBeInteresting(MI->first,
                                                                  Callbacks)))
          break;

    // If this function call cannot impact the analysis (either because the
    // nodes we are tracking are not passed into the call, or the DSGraph for
    // the callee tells us that analysis of the callee can't provide interesting
    // information), ignore it.
    if (!CallCanModifyDataFlow)
      continue;

    // Okay, either compute analysis results for the callee function, or reuse
    // results previously computed.
    std::multimap<DSNode*, LatticeValue*> &CalleeFacts = getCalleeFacts(*CG);

    // Merge all of the facts for the callee into the facts for the caller.  If
    // this reduces anything in the caller to 'bottom', remove them.
    for (DSGraph::NodeMapTy::iterator MI = CallNodeMap.begin(),
           E = CallNodeMap.end(); MI != E; ++MI) {
      // If we have Lattice facts in the caller for this node in the callee,
      // merge any information from the callee into the caller.

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