1 //== ----- llvm/CodeGen/GlobalISel/Combiner.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 /// \file
9 /// This contains the base class for all Combiners generated by TableGen.
10 /// Backends need to create class that inherits from "Combiner" and put all of
11 /// the TableGen-erated code in there, as it implements the virtual functions.
12 ///
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_CODEGEN_GLOBALISEL_COMBINER_H
16 #define LLVM_CODEGEN_GLOBALISEL_COMBINER_H
17 
18 #include "llvm/CodeGen/GlobalISel/GIMatchTableExecutor.h"
19 #include "llvm/CodeGen/GlobalISel/GISelChangeObserver.h"
20 #include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
21 
22 namespace llvm {
23 class MachineRegisterInfo;
24 struct CombinerInfo;
25 class GISelCSEInfo;
26 class TargetPassConfig;
27 class MachineFunction;
28 class MachineIRBuilder;
29 
30 /// Combiner implementation. This is per-function, so passes need to recreate
31 /// one of these each time they enter a new function.
32 ///
33 /// TODO: Is it worth making this module-wide?
34 class Combiner : public GIMatchTableExecutor {
35 private:
36   class WorkListMaintainer;
37   GISelWorkList<512> WorkList;
38 
39   // We have a little hack here where keep the owned pointers private, and only
40   // expose a reference. This has two purposes:
41   //  - Avoid derived classes messing with those pointers.
42   //  - Keep the API consistent. CInfo, MF, MRI, etc. are all accessed as
43   //  references. Accessing Observer/B as pointers unnecessarily leaks
44   //  implementation details into derived classes.
45   std::unique_ptr<MachineIRBuilder> Builder;
46   std::unique_ptr<WorkListMaintainer> WLObserver;
47   std::unique_ptr<GISelObserverWrapper> ObserverWrapper;
48 
49   bool HasSetupMF = false;
50 
51 public:
52   /// If CSEInfo is not null, then the Combiner will use CSEInfo as the observer
53   /// and also create a CSEMIRBuilder. Pass nullptr if CSE is not needed.
54   Combiner(MachineFunction &MF, CombinerInfo &CInfo,
55            const TargetPassConfig *TPC, GISelKnownBits *KB,
56            GISelCSEInfo *CSEInfo = nullptr);
57   virtual ~Combiner();
58 
59   virtual bool tryCombineAll(MachineInstr &I) const = 0;
60 
61   bool combineMachineInstrs();
62 
63 protected:
64   CombinerInfo &CInfo;
65   GISelChangeObserver &Observer;
66   MachineIRBuilder &B;
67   MachineFunction &MF;
68   MachineRegisterInfo &MRI;
69   GISelKnownBits *KB;
70 
71   const TargetPassConfig *TPC;
72   GISelCSEInfo *CSEInfo;
73 };
74 
75 } // End namespace llvm.
76 
77 #endif // LLVM_CODEGEN_GLOBALISEL_COMBINER_H
78