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      1 //===-------- EdgeBundles.h - Bundles of CFG edges --------------*- c++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // The EdgeBundles analysis forms equivalence classes of CFG edges such that all
     11 // edges leaving a machine basic block are in the same bundle, and all edges
     12 // leaving a basic block are in the same bundle.
     13 //
     14 //===----------------------------------------------------------------------===//
     15 
     16 #ifndef LLVM_CODEGEN_EDGEBUNDLES_H
     17 #define LLVM_CODEGEN_EDGEBUNDLES_H
     18 
     19 #include "llvm/ADT/ArrayRef.h"
     20 #include "llvm/ADT/IntEqClasses.h"
     21 #include "llvm/CodeGen/MachineFunctionPass.h"
     22 
     23 namespace llvm {
     24 
     25 class EdgeBundles : public MachineFunctionPass {
     26   const MachineFunction *MF;
     27 
     28   /// EC - Each edge bundle is an equivalence class. The keys are:
     29   ///   2*BB->getNumber()   -> Ingoing bundle.
     30   ///   2*BB->getNumber()+1 -> Outgoing bundle.
     31   IntEqClasses EC;
     32 
     33   /// Blocks - Map each bundle to a list of basic block numbers.
     34   SmallVector<SmallVector<unsigned, 8>, 4> Blocks;
     35 
     36 public:
     37   static char ID;
     38   EdgeBundles() : MachineFunctionPass(ID) {}
     39 
     40   /// getBundle - Return the ingoing (Out = false) or outgoing (Out = true)
     41   /// bundle number for basic block #N
     42   unsigned getBundle(unsigned N, bool Out) const { return EC[2 * N + Out]; }
     43 
     44   /// getNumBundles - Return the total number of bundles in the CFG.
     45   unsigned getNumBundles() const { return EC.getNumClasses(); }
     46 
     47   /// getBlocks - Return an array of blocks that are connected to Bundle.
     48   ArrayRef<unsigned> getBlocks(unsigned Bundle) { return Blocks[Bundle]; }
     49 
     50   /// getMachineFunction - Return the last machine function computed.
     51   const MachineFunction *getMachineFunction() const { return MF; }
     52 
     53   /// view - Visualize the annotated bipartite CFG with Graphviz.
     54   void view() const;
     55 
     56 private:
     57   virtual bool runOnMachineFunction(MachineFunction&);
     58   virtual void getAnalysisUsage(AnalysisUsage&) const;
     59 };
     60 
     61 /// Specialize WriteGraph, the standard implementation won't work.
     62 raw_ostream &WriteGraph(raw_ostream &O, const EdgeBundles &G,
     63                         bool ShortNames = false,
     64                         const std::string &Title = "");
     65 
     66 } // end namespace llvm
     67 
     68 #endif
     69