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      1 //===-------- EdgeBundles.h - Bundles of CFG edges --------------*- c++ -*-===//
      2 //
      3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
      4 // See https://llvm.org/LICENSE.txt for license information.
      5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
      6 //
      7 //===----------------------------------------------------------------------===//
      8 //
      9 // The EdgeBundles analysis forms equivalence classes of CFG edges such that all
     10 // edges leaving a machine basic block are in the same bundle, and all edges
     11 // entering a machine basic block are in the same bundle.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #ifndef LLVM_CODEGEN_EDGEBUNDLES_H
     16 #define LLVM_CODEGEN_EDGEBUNDLES_H
     17 
     18 #include "llvm/ADT/ArrayRef.h"
     19 #include "llvm/ADT/IntEqClasses.h"
     20 #include "llvm/CodeGen/MachineFunctionPass.h"
     21 
     22 namespace llvm {
     23 
     24 class EdgeBundles : public MachineFunctionPass {
     25   const MachineFunction *MF;
     26 
     27   /// EC - Each edge bundle is an equivalence class. The keys are:
     28   ///   2*BB->getNumber()   -> Ingoing bundle.
     29   ///   2*BB->getNumber()+1 -> Outgoing bundle.
     30   IntEqClasses EC;
     31 
     32   /// Blocks - Map each bundle to a list of basic block numbers.
     33   SmallVector<SmallVector<unsigned, 8>, 4> Blocks;
     34 
     35 public:
     36   static char ID;
     37   EdgeBundles() : MachineFunctionPass(ID) {}
     38 
     39   /// getBundle - Return the ingoing (Out = false) or outgoing (Out = true)
     40   /// bundle number for basic block #N
     41   unsigned getBundle(unsigned N, bool Out) const { return EC[2 * N + Out]; }
     42 
     43   /// getNumBundles - Return the total number of bundles in the CFG.
     44   unsigned getNumBundles() const { return EC.getNumClasses(); }
     45 
     46   /// getBlocks - Return an array of blocks that are connected to Bundle.
     47   ArrayRef<unsigned> getBlocks(unsigned Bundle) const { return Blocks[Bundle]; }
     48 
     49   /// getMachineFunction - Return the last machine function computed.
     50   const MachineFunction *getMachineFunction() const { return MF; }
     51 
     52   /// view - Visualize the annotated bipartite CFG with Graphviz.
     53   void view() const;
     54 
     55 private:
     56   bool runOnMachineFunction(MachineFunction&) override;
     57   void getAnalysisUsage(AnalysisUsage&) const override;
     58 };
     59 
     60 } // end namespace llvm
     61 
     62 #endif
     63