1 //===- llvm/CodeGen/PBQPRAConstraint.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 the PBQPBuilder interface, for classes which build PBQP
10 // instances to represent register allocation problems, and the RegAllocPBQP
11 // interface.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_CODEGEN_PBQPRACONSTRAINT_H
16 #define LLVM_CODEGEN_PBQPRACONSTRAINT_H
17 
18 #include <algorithm>
19 #include <memory>
20 #include <vector>
21 
22 namespace llvm {
23 
24 namespace PBQP {
25 namespace RegAlloc {
26 
27 // Forward declare PBQP graph class.
28 class PBQPRAGraph;
29 
30 } // end namespace RegAlloc
31 } // end namespace PBQP
32 
33 using PBQPRAGraph = PBQP::RegAlloc::PBQPRAGraph;
34 
35 /// Abstract base for classes implementing PBQP register allocation
36 ///        constraints (e.g. Spill-costs, interference, coalescing).
37 class PBQPRAConstraint {
38 public:
39   virtual ~PBQPRAConstraint() = 0;
40   virtual void apply(PBQPRAGraph &G) = 0;
41 
42 private:
43   virtual void anchor();
44 };
45 
46 /// PBQP register allocation constraint composer.
47 ///
48 ///   Constraints added to this list will be applied, in the order that they are
49 /// added, to the PBQP graph.
50 class PBQPRAConstraintList : public PBQPRAConstraint {
51 public:
52   void apply(PBQPRAGraph &G) override {
53     for (auto &C : Constraints)
54       C->apply(G);
55   }
56 
57   void addConstraint(std::unique_ptr<PBQPRAConstraint> C) {
58     if (C)
59       Constraints.push_back(std::move(C));
60   }
61 
62 private:
63   std::vector<std::unique_ptr<PBQPRAConstraint>> Constraints;
64 
65   void anchor() override;
66 };
67 
68 } // end namespace llvm
69 
70 #endif // LLVM_CODEGEN_PBQPRACONSTRAINT_H
71