aboutsummaryrefslogtreecommitdiffstats
path: root/include/llvm/Target/TargetSubtargetInfo.h
blob: bb5409b6079ff7beca0637f81c6f6674bca3c6e7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
//==-- llvm/Target/TargetSubtargetInfo.h - Target Information ----*- C++ -*-==//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file describes the subtarget options of a Target machine.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_TARGET_TARGETSUBTARGETINFO_H
#define LLVM_TARGET_TARGETSUBTARGETINFO_H

#include "llvm/CodeGen/PBQPRAConstraint.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/Support/CodeGen.h"

namespace llvm {

class DataLayout;
class MachineFunction;
class MachineInstr;
class SDep;
class SUnit;
class TargetFrameLowering;
class TargetInstrInfo;
class TargetLowering;
class TargetRegisterClass;
class TargetRegisterInfo;
class TargetSchedModel;
class TargetSelectionDAGInfo;
struct MachineSchedPolicy;
template <typename T> class SmallVectorImpl;

//===----------------------------------------------------------------------===//
///
/// TargetSubtargetInfo - Generic base class for all target subtargets.  All
/// Target-specific options that control code generation and printing should
/// be exposed through a TargetSubtargetInfo-derived class.
///
class TargetSubtargetInfo : public MCSubtargetInfo {
  TargetSubtargetInfo(const TargetSubtargetInfo&) = delete;
  void operator=(const TargetSubtargetInfo&) = delete;
protected: // Can only create subclasses...
  TargetSubtargetInfo();
public:
  // AntiDepBreakMode - Type of anti-dependence breaking that should
  // be performed before post-RA scheduling.
  typedef enum { ANTIDEP_NONE, ANTIDEP_CRITICAL, ANTIDEP_ALL } AntiDepBreakMode;
  typedef SmallVectorImpl<const TargetRegisterClass*> RegClassVector;

  virtual ~TargetSubtargetInfo();

  // Interfaces to the major aspects of target machine information:
  //
  // -- Instruction opcode and operand information
  // -- Pipelines and scheduling information
  // -- Stack frame information
  // -- Selection DAG lowering information
  //
  // N.B. These objects may change during compilation. It's not safe to cache
  // them between functions.
  virtual const TargetInstrInfo *getInstrInfo() const { return nullptr; }
  virtual const TargetFrameLowering *getFrameLowering() const {
    return nullptr;
  }
  virtual const TargetLowering *getTargetLowering() const { return nullptr; }
  virtual const TargetSelectionDAGInfo *getSelectionDAGInfo() const {
    return nullptr;
  }

  /// getRegisterInfo - If register information is available, return it.  If
  /// not, return null.  This is kept separate from RegInfo until RegInfo has
  /// details of graph coloring register allocation removed from it.
  ///
  virtual const TargetRegisterInfo *getRegisterInfo() const { return nullptr; }

  /// getInstrItineraryData - Returns instruction itinerary data for the target
  /// or specific subtarget.
  ///
  virtual const InstrItineraryData *getInstrItineraryData() const {
    return nullptr;
  }

  /// Resolve a SchedClass at runtime, where SchedClass identifies an
  /// MCSchedClassDesc with the isVariant property. This may return the ID of
  /// another variant SchedClass, but repeated invocation must quickly terminate
  /// in a nonvariant SchedClass.
  virtual unsigned resolveSchedClass(unsigned SchedClass, const MachineInstr *MI,
                                     const TargetSchedModel* SchedModel) const {
    return 0;
  }

  /// \brief True if the subtarget should run MachineScheduler after aggressive
  /// coalescing.
  ///
  /// This currently replaces the SelectionDAG scheduler with the "source" order
  /// scheduler (though see below for an option to turn this off and use the
  /// TargetLowering preference). It does not yet disable the postRA scheduler.
  virtual bool enableMachineScheduler() const;

  /// \brief True if the machine scheduler should disable the TLI preference
  /// for preRA scheduling with the source level scheduler.
  virtual bool enableMachineSchedDefaultSched() const { return true; }

  /// \brief True if the subtarget should enable joining global copies.
  ///
  /// By default this is enabled if the machine scheduler is enabled, but
  /// can be overridden.
  virtual bool enableJoinGlobalCopies() const;

  /// \brief True if the subtarget should run PostMachineScheduler.
  ///
  /// This only takes effect if the target has configured the
  /// PostMachineScheduler pass to run, or if the global cl::opt flag,
  /// MISchedPostRA, is set.
  virtual bool enablePostMachineScheduler() const;

  /// \brief True if the subtarget should run the atomic expansion pass.
  virtual bool enableAtomicExpand() const;

  /// \brief Override generic scheduling policy within a region.
  ///
  /// This is a convenient way for targets that don't provide any custom
  /// scheduling heuristics (no custom MachineSchedStrategy) to make
  /// changes to the generic scheduling policy.
  virtual void overrideSchedPolicy(MachineSchedPolicy &Policy,
                                   MachineInstr *begin,
                                   MachineInstr *end,
                                   unsigned NumRegionInstrs) const {}

  // \brief Perform target specific adjustments to the latency of a schedule
  // dependency.
  virtual void adjustSchedDependency(SUnit *def, SUnit *use,
                                     SDep& dep) const { }

  // For use with PostRAScheduling: get the anti-dependence breaking that should
  // be performed before post-RA scheduling.
  virtual AntiDepBreakMode getAntiDepBreakMode() const {
    return ANTIDEP_NONE;
  }

  // For use with PostRAScheduling: in CriticalPathRCs, return any register
  // classes that should only be considered for anti-dependence breaking if they
  // are on the critical path.
  virtual void getCriticalPathRCs(RegClassVector &CriticalPathRCs) const {
    return CriticalPathRCs.clear();
  }

  // For use with PostRAScheduling: get the minimum optimization level needed
  // to enable post-RA scheduling.
  virtual CodeGenOpt::Level getOptLevelToEnablePostRAScheduler() const {
    return CodeGenOpt::Default;
  }

  /// \brief True if the subtarget should run the local reassignment
  /// heuristic of the register allocator.
  /// This heuristic may be compile time intensive, \p OptLevel provides
  /// a finer grain to tune the register allocator.
  virtual bool enableRALocalReassignment(CodeGenOpt::Level OptLevel) const;

  /// \brief Enable use of alias analysis during code generation (during MI
  /// scheduling, DAGCombine, etc.).
  virtual bool useAA() const;

  /// \brief Enable the use of the early if conversion pass.
  virtual bool enableEarlyIfConversion() const { return false; }

  /// \brief Return PBQPConstraint(s) for the target.
  ///
  /// Override to provide custom PBQP constraints.
  virtual std::unique_ptr<PBQPRAConstraint> getCustomPBQPConstraints() const {
    return nullptr;
  }

  /// Enable tracking of subregister liveness in register allocator.
  virtual bool enableSubRegLiveness() const {
    return false;
  }
};

} // End llvm namespace

#endif