//===- MemoryDepAnalysis.h - Compute dep graph for memory ops ---*- C++ -*-===//
// 
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
// 
//===----------------------------------------------------------------------===//
//
// This file provides a pass (MemoryDepAnalysis) that computes memory-based
// data dependences between instructions for each function in a module.  
// Memory-based dependences occur due to load and store operations, but
// also the side-effects of call instructions.
//
// The result of this pass is a DependenceGraph for each function
// representing the memory-based data dependences between instructions.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_ANALYSIS_MEMORYDEPANALYSIS_H
#define LLVM_ANALYSIS_MEMORYDEPANALYSIS_H

#include "DependenceGraph.h"
#include "llvm/Pass.h"
#include "llvm/ADT/hash_map"

namespace llvm {

class ModRefTable;
class DSGraph;
class FunctionModRefInfo;

///---------------------------------------------------------------------------
/// class MemoryDepGraph:
///   Dependence analysis for load/store/call instructions using IPModRef info
///   computed at the granularity of individual DSGraph nodes.
///
/// This pass computes memory dependences for each function in a module.
/// It can be made a FunctionPass once a Pass (such as Parallelize) is
/// allowed to use a FunctionPass such as this one.
///---------------------------------------------------------------------------

class MemoryDepAnalysis : public ModulePass {
  /// The following map and depGraph pointer are temporary until this class
  /// becomes a FunctionPass instead of a module Pass.
  hash_map<Function*, DependenceGraph*> funcMap;
  DependenceGraph* funcDepGraph;

  /// Information about one function being analyzed.
  const DSGraph*  funcGraph;
  const FunctionModRefInfo* funcModRef;

  /// Internal routine that processes each SCC of the CFG.
  ///
  void ProcessSCC(std::vector<BasicBlock*> &SCC, ModRefTable& ModRefAfter,
                  bool HasLoop);

  friend class PgmDependenceGraph;

public:
  MemoryDepAnalysis() : funcDepGraph(0), funcGraph(0), funcModRef(0) {}
  ~MemoryDepAnalysis();

  /// Driver function to compute dependence graphs for every function.
  ///
  bool runOnModule(Module &M);

  /// getGraph - Retrieve the dependence graph for a function.
  /// This is temporary and will go away once this is a FunctionPass.
  /// At that point, this class should directly inherit from DependenceGraph.
  /// 
  DependenceGraph& getGraph(Function& F) {
    hash_map<Function*, DependenceGraph*>::iterator I = funcMap.find(&F);
    assert(I != funcMap.end());
    return *I->second;
  }
  const DependenceGraph& getGraph(Function& F) const {
    hash_map<Function*, DependenceGraph*>::const_iterator I = funcMap.find(&F);
    assert(I != funcMap.end());
    return *I->second;
  }

  /// Release depGraphs held in the Function -> DepGraph map.
  /// 
  virtual void releaseMemory();

  /// Driver functions to compute the Load/Store Dep. Graph per function.
  /// 
  bool runOnFunction(Function &F);

  /// getAnalysisUsage - This does not modify anything.  It uses the Top-Down DS
  /// Graph and IPModRef.
  void getAnalysisUsage(AnalysisUsage &AU) const;

  /// Debugging support methods
  /// 
  void print(std::ostream &O, const Module* = 0) const;
  void dump() const;
};

} // End llvm namespace

#endif
