path: root/lib/Analysis/DataStructure/DataStructure.cpp

//===- DataStructure.cpp - Implement the core data structure analysis -----===//
//
// This file implements the core data structure functionality.
//
//===----------------------------------------------------------------------===//

#include "llvm/Module.h"
#include "llvm/DerivedTypes.h"
#include "Support/STLExtras.h"
#include "Support/StatisticReporter.h"
#include "Support/STLExtras.h"
#include <algorithm>
#include <set>
#include "llvm/Analysis/DataStructure.h"

using std::vector;

//===----------------------------------------------------------------------===//
// DSNode Implementation
//===----------------------------------------------------------------------===//

DSNode::DSNode(enum NodeTy NT, const Type *T) : Ty(T), NodeType(NT) {
  // If this node has any fields, allocate them now, but leave them null.
  switch (T->getPrimitiveID()) {
  case Type::PointerTyID: Links.resize(1); break;
  case Type::ArrayTyID:   Links.resize(1); break;
  case Type::StructTyID:
    Links.resize(cast<StructType>(T)->getNumContainedTypes());
    break;
  default: break;
  }
}

// DSNode copy constructor... do not copy over the referrers list!
DSNode::DSNode(const DSNode &N)
  : Ty(N.Ty), Links(N.Links), Globals(N.Globals), NodeType(N.NodeType) {
}

void DSNode::removeReferrer(DSNodeHandle *H) {
  // Search backwards, because we depopulate the list from the back for
  // efficiency (because it's a vector).
  vector<DSNodeHandle*>::reverse_iterator I =
    std::find(Referrers.rbegin(), Referrers.rend(), H);
  assert(I != Referrers.rend() && "Referrer not pointing to node!");
  Referrers.erase(I.base()-1);
}

// addGlobal - Add an entry for a global value to the Globals list.  This also
// marks the node with the 'G' flag if it does not already have it.
//
void DSNode::addGlobal(GlobalValue *GV) {
  // Keep the list sorted.
  vector<GlobalValue*>::iterator I =
    std::lower_bound(Globals.begin(), Globals.end(), GV);

  if (I == Globals.end() || *I != GV) {
    assert(GV->getType()->getElementType() == Ty);
    Globals.insert(I, GV);
    NodeType |= GlobalNode;
  }
}


// addEdgeTo - Add an edge from the current node to the specified node.  This
// can cause merging of nodes in the graph.
//
void DSNode::addEdgeTo(unsigned LinkNo, DSNode *N) {
  assert(LinkNo < Links.size() && "LinkNo out of range!");
  if (N == 0 || Links[LinkNo] == N) return;  // Nothing to do
  if (Links[LinkNo] == 0) {                  // No merging to perform
    Links[LinkNo] = N;
    return;
  }

  // Merge the two nodes...
  Links[LinkNo]->mergeWith(N);
}


// mergeWith - Merge this node into the specified node, moving all links to and
// from the argument node into the current node.  The specified node may be a
// null pointer (in which case, nothing happens).
//
void DSNode::mergeWith(DSNode *N) {
  if (N == 0 || N == this) return;  // Noop
  assert(N->Ty == Ty && N->Links.size() == Links.size() &&
         "Cannot merge nodes of two different types!");

  // Remove all edges pointing at N, causing them to point to 'this' instead.
  while (!N->Referrers.empty())
    *N->Referrers.back() = this;

  // Make all of the outgoing links of N now be outgoing links of this.  This
  // can cause recursive merging!
  //
  for (unsigned i = 0, e = Links.size(); i != e; ++i) {
    addEdgeTo(i, N->Links[i]);
    N->Links[i] = 0;  // Reduce unneccesary edges in graph. N is dead
  }

  // Merge the node types
  NodeType |= N->NodeType;
  N->NodeType = 0;   // N is now a dead node.

  // Merge the globals list...
  if (!N->Globals.empty()) {
    // Save the current globals off to the side...
    vector<GlobalValue*> OldGlobals(Globals);

    // Resize the globals vector to be big enough to hold both of them...
    Globals.resize(Globals.size()+N->Globals.size());

    // Merge the two sorted globals lists together...
    std::merge(OldGlobals.begin(), OldGlobals.end(),
               N->Globals.begin(), N->Globals.end(), Globals.begin());

    // Erase duplicate entries from the globals list...
    Globals.erase(std::unique(Globals.begin(), Globals.end()), Globals.end());

    // Delete the globals from the old node...
    N->Globals.clear();
  }
}

//===----------------------------------------------------------------------===//
// DSGraph Implementation
//===----------------------------------------------------------------------===//

DSGraph::DSGraph(const DSGraph &G) : Func(G.Func) {
  std::map<const DSNode*, DSNode*> NodeMap; // ignored
  RetNode = cloneInto(G, ValueMap, NodeMap, false);
}

DSGraph::~DSGraph() {
  FunctionCalls.clear();
  OrigFunctionCalls.clear();
  ValueMap.clear();
  RetNode = 0;

#ifndef NDEBUG
  // Drop all intra-node references, so that assertions don't fail...
  std::for_each(Nodes.begin(), Nodes.end(),
                std::mem_fun(&DSNode::dropAllReferences));
#endif

  // Delete all of the nodes themselves...
  std::for_each(Nodes.begin(), Nodes.end(), deleter<DSNode>);
}

// dump - Allow inspection of graph in a debugger.
void DSGraph::dump() const { print(std::cerr); }


// cloneInto - Clone the specified DSGraph into the current graph, returning the
// Return node of the graph.  The translated ValueMap for the old function is
// filled into the OldValMap member.  If StripLocals is set to true, Scalar and
// Alloca markers are removed from the graph, as the graph is being cloned into
// a calling function's graph.
//
DSNode *DSGraph::cloneInto(const DSGraph &G, 
                           std::map<Value*, DSNodeHandle> &OldValMap,
                           std::map<const DSNode*, DSNode*> &OldNodeMap,
                           bool StripLocals) {

  assert(OldNodeMap.size()==0 && "Return argument OldNodeMap should be empty");

  OldNodeMap[0] = 0;  // Null pointer maps to null

  unsigned FN = Nodes.size();  // FirstNode...

  // Duplicate all of the nodes, populating the node map...
  Nodes.reserve(FN+G.Nodes.size());
  for (unsigned i = 0, e = G.Nodes.size(); i != e; ++i) {
    DSNode *Old = G.Nodes[i], *New = new DSNode(*Old);
    Nodes.push_back(New);
    OldNodeMap[Old] = New;
  }

  // Rewrite the links in the nodes to point into the current graph now.
  for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
    for (unsigned j = 0, e = Nodes[i]->getNumLinks(); j != e; ++j)
      Nodes[i]->setLink(j, OldNodeMap[Nodes[i]->getLink(j)]);

  // If we are inlining this graph into the called function graph, remove local
  // markers.
  if (StripLocals)
    for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
      Nodes[i]->NodeType &= ~(DSNode::AllocaNode | DSNode::ScalarNode);

  // Copy the value map...
  for (std::map<Value*, DSNodeHandle>::const_iterator I = G.ValueMap.begin(),
         E = G.ValueMap.end(); I != E; ++I)
    OldValMap[I->first] = OldNodeMap[I->second];

  // Copy the function calls list...
  unsigned FC = FunctionCalls.size();  // FirstCall
  FunctionCalls.reserve(FC+G.FunctionCalls.size());
  for (unsigned i = 0, e = G.FunctionCalls.size(); i != e; ++i) {
    FunctionCalls.push_back(std::vector<DSNodeHandle>());
    FunctionCalls[FC+i].reserve(G.FunctionCalls[i].size());
    for (unsigned j = 0