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       1             : //===- llvm/Transforms/Utils/OrderedInstructions.h -------------*- 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             : // This file defines an efficient way to check for dominance relation between 2
      11             : // instructions.
      12             : //
      13             : // This interface dispatches to appropriate dominance check given 2
      14             : // instructions, i.e. in case the instructions are in the same basic block,
      15             : // OrderedBasicBlock (with instruction numbering and caching) are used.
      16             : // Otherwise, dominator tree is used.
      17             : //
      18             : //===----------------------------------------------------------------------===//
      19             : 
      20             : #ifndef LLVM_TRANSFORMS_UTILS_ORDEREDINSTRUCTIONS_H
      21             : #define LLVM_TRANSFORMS_UTILS_ORDEREDINSTRUCTIONS_H
      22             : 
      23             : #include "llvm/ADT/DenseMap.h"
      24             : #include "llvm/Analysis/OrderedBasicBlock.h"
      25             : #include "llvm/IR/Dominators.h"
      26             : #include "llvm/IR/Operator.h"
      27             : 
      28             : namespace llvm {
      29             : 
      30         669 : class OrderedInstructions {
      31             :   /// Used to check dominance for instructions in same basic block.
      32             :   mutable DenseMap<const BasicBlock *, std::unique_ptr<OrderedBasicBlock>>
      33             :       OBBMap;
      34             : 
      35             :   /// The dominator tree of the parent function.
      36             :   DominatorTree *DT;
      37             : 
      38             :   /// Return true if the first instruction comes before the second in the
      39             :   /// same basic block. It will create an ordered basic block, if it does
      40             :   /// not yet exist in OBBMap.
      41             :   bool localDominates(const Instruction *, const Instruction *) const;
      42             : 
      43             : public:
      44             :   /// Constructor.
      45       70856 :   OrderedInstructions(DominatorTree *DT) : DT(DT) {}
      46             : 
      47             :   /// Return true if first instruction dominates the second.
      48             :   bool dominates(const Instruction *, const Instruction *) const;
      49             : 
      50             :   /// Return true if the first instruction comes before the second in the
      51             :   /// dominator tree DFS traversal if they are in different basic blocks,
      52             :   /// or if the first instruction comes before the second in the same basic
      53             :   /// block.
      54             :   bool dfsBefore(const Instruction *, const Instruction *) const;
      55             : 
      56             :   /// Invalidate the OrderedBasicBlock cache when its basic block changes.
      57             :   /// i.e. If an instruction is deleted or added to the basic block, the user
      58             :   /// should call this function to invalidate the OrderedBasicBlock cache for
      59             :   /// this basic block.
      60       17063 :   void invalidateBlock(const BasicBlock *BB) { OBBMap.erase(BB); }
      61             : };
      62             : 
      63             : } // end namespace llvm
      64             : 
      65             : #endif // LLVM_TRANSFORMS_UTILS_ORDEREDINSTRUCTIONS_H