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