1 //===- MachineScheduler.cpp - Machine Instruction Scheduler ---------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // MachineScheduler schedules machine instructions after phi elimination. It
11 // preserves LiveIntervals so it can be invoked before register allocation.
13 //===----------------------------------------------------------------------===//
15 #define DEBUG_TYPE "misched"
17 #include "ScheduleDAGInstrs.h"
18 #include "LiveDebugVariables.h"
19 #include "llvm/CodeGen/LiveIntervalAnalysis.h"
20 #include "llvm/CodeGen/MachinePassRegistry.h"
21 #include "llvm/CodeGen/Passes.h"
22 #include "llvm/Analysis/AliasAnalysis.h"
23 #include "llvm/Support/CommandLine.h"
24 #include "llvm/Support/Debug.h"
25 #include "llvm/Support/ErrorHandling.h"
26 #include "llvm/Support/raw_ostream.h"
27 #include "llvm/ADT/OwningPtr.h"
31 //===----------------------------------------------------------------------===//
32 // Machine Instruction Scheduling Pass and Registry
33 //===----------------------------------------------------------------------===//
36 /// MachineSchedulerPass runs after coalescing and before register allocation.
37 class MachineSchedulerPass : public MachineFunctionPass {
40 const TargetInstrInfo *TII;
41 const MachineLoopInfo *MLI;
42 const MachineDominatorTree *MDT;
44 MachineSchedulerPass();
46 virtual void getAnalysisUsage(AnalysisUsage &AU) const;
48 virtual void releaseMemory() {}
50 virtual bool runOnMachineFunction(MachineFunction&);
52 virtual void print(raw_ostream &O, const Module* = 0) const;
54 static char ID; // Class identification, replacement for typeinfo
58 char MachineSchedulerPass::ID = 0;
60 char &llvm::MachineSchedulerPassID = MachineSchedulerPass::ID;
62 INITIALIZE_PASS_BEGIN(MachineSchedulerPass, "misched",
63 "Machine Instruction Scheduler", false, false)
64 INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
65 INITIALIZE_PASS_DEPENDENCY(SlotIndexes)
66 INITIALIZE_PASS_DEPENDENCY(LiveIntervals)
67 INITIALIZE_PASS_DEPENDENCY(LiveDebugVariables)
68 INITIALIZE_PASS_DEPENDENCY(StrongPHIElimination)
69 INITIALIZE_PASS_DEPENDENCY(RegisterCoalescer)
70 INITIALIZE_PASS_END(MachineSchedulerPass, "misched",
71 "Machine Instruction Scheduler", false, false)
73 MachineSchedulerPass::MachineSchedulerPass()
74 : MachineFunctionPass(ID), MF(0), MLI(0), MDT(0) {
75 initializeMachineSchedulerPassPass(*PassRegistry::getPassRegistry());
78 void MachineSchedulerPass::getAnalysisUsage(AnalysisUsage &AU) const {
80 AU.addRequiredID(MachineDominatorsID);
81 AU.addRequired<MachineLoopInfo>();
82 AU.addRequired<AliasAnalysis>();
83 AU.addPreserved<AliasAnalysis>();
84 AU.addRequired<SlotIndexes>();
85 AU.addPreserved<SlotIndexes>();
86 AU.addRequired<LiveIntervals>();
87 AU.addPreserved<LiveIntervals>();
88 AU.addRequired<LiveDebugVariables>();
89 AU.addPreserved<LiveDebugVariables>();
91 AU.addRequiredID(StrongPHIEliminationID);
92 AU.addPreservedID(StrongPHIEliminationID);
94 AU.addRequiredID(RegisterCoalescerPassID);
95 AU.addPreservedID(RegisterCoalescerPassID);
96 MachineFunctionPass::getAnalysisUsage(AU);
100 /// MachineSchedRegistry provides a selection of available machine instruction
102 class MachineSchedRegistry : public MachinePassRegistryNode {
104 typedef ScheduleDAGInstrs *(*ScheduleDAGCtor)(MachineSchedulerPass *);
106 // RegisterPassParser requires a (misnamed) FunctionPassCtor type.
107 typedef ScheduleDAGCtor FunctionPassCtor;
109 static MachinePassRegistry Registry;
111 MachineSchedRegistry(const char *N, const char *D, ScheduleDAGCtor C)
112 : MachinePassRegistryNode(N, D, (MachinePassCtor)C) {
115 ~MachineSchedRegistry() { Registry.Remove(this); }
119 MachineSchedRegistry *getNext() const {
120 return (MachineSchedRegistry *)MachinePassRegistryNode::getNext();
122 static MachineSchedRegistry *getList() {
123 return (MachineSchedRegistry *)Registry.getList();
125 static ScheduleDAGCtor getDefault() {
126 return (ScheduleDAGCtor)Registry.getDefault();
128 static void setDefault(ScheduleDAGCtor C) {
129 Registry.setDefault((MachinePassCtor)C);
131 static void setListener(MachinePassRegistryListener *L) {
132 Registry.setListener(L);
137 MachinePassRegistry MachineSchedRegistry::Registry;
139 static ScheduleDAGInstrs *createDefaultMachineSched(MachineSchedulerPass *P);
141 /// MachineSchedOpt allows command line selection of the scheduler.
142 static cl::opt<MachineSchedRegistry::ScheduleDAGCtor, false,
143 RegisterPassParser<MachineSchedRegistry> >
144 MachineSchedOpt("misched",
145 cl::init(&createDefaultMachineSched), cl::Hidden,
146 cl::desc("Machine instruction scheduler to use"));
148 //===----------------------------------------------------------------------===//
149 // Machine Instruction Scheduling Implementation
150 //===----------------------------------------------------------------------===//
153 /// MachineScheduler is an implementation of ScheduleDAGInstrs that schedules
154 /// machine instructions while updating LiveIntervals.
155 class MachineScheduler : public ScheduleDAGInstrs {
156 MachineSchedulerPass *Pass;
158 MachineScheduler(MachineSchedulerPass *P):
159 ScheduleDAGInstrs(*P->MF, *P->MLI, *P->MDT), Pass(P) {}
161 /// Schedule - This is called back from ScheduleDAGInstrs::Run() when it's
162 /// time to do some work.
163 virtual void Schedule();
167 static ScheduleDAGInstrs *createDefaultMachineSched(MachineSchedulerPass *P) {
168 return new MachineScheduler(P);
170 static MachineSchedRegistry
171 SchedDefaultRegistry("default", "Activate the scheduler pass, "
172 "but don't reorder instructions",
173 createDefaultMachineSched);
175 /// Schedule - This is called back from ScheduleDAGInstrs::Run() when it's
176 /// time to do some work.
177 void MachineScheduler::Schedule() {
178 DEBUG(dbgs() << "********** MI Scheduling **********\n");
179 DEBUG(for (unsigned su = 0, e = SUnits.size(); su != e; ++su)
180 SUnits[su].dumpAll(this));
181 // TODO: Put interesting things here.
184 bool MachineSchedulerPass::runOnMachineFunction(MachineFunction &mf) {
185 // Initialize the context of the pass.
187 MLI = &getAnalysis<MachineLoopInfo>();
188 MDT = &getAnalysis<MachineDominatorTree>();
189 TII = MF->getTarget().getInstrInfo();
191 // Select the scheduler, or set the default.
192 MachineSchedRegistry::ScheduleDAGCtor Ctor =
193 MachineSchedRegistry::getDefault();
195 Ctor = MachineSchedOpt;
196 MachineSchedRegistry::setDefault(Ctor);
198 // Instantiate the selected scheduler.
199 OwningPtr<ScheduleDAGInstrs> Scheduler(Ctor(this));
201 // Visit all machine basic blocks.
202 for (MachineFunction::iterator MBB = MF->begin(), MBBEnd = MF->end();
203 MBB != MBBEnd; ++MBB) {
205 DEBUG(dbgs() << "MachineScheduling " << MF->getFunction()->getName()
206 << ":BB#" << MBB->getNumber() << "\n");
208 // Inform ScheduleDAGInstrs of the region being scheduler. It calls back
209 // to our Schedule() method.
210 Scheduler->Run(MBB, MBB->begin(), MBB->end(), MBB->size());
215 void MachineSchedulerPass::print(raw_ostream &O, const Module* m) const {
219 //===----------------------------------------------------------------------===//
220 // Machine Instruction Shuffler for Correctness Testing
221 //===----------------------------------------------------------------------===//
225 /// Reorder instructions as much as possible.
226 class InstructionShuffler : public ScheduleDAGInstrs {
227 MachineSchedulerPass *Pass;
229 InstructionShuffler(MachineSchedulerPass *P):
230 ScheduleDAGInstrs(*P->MF, *P->MLI, *P->MDT), Pass(P) {}
232 /// Schedule - This is called back from ScheduleDAGInstrs::Run() when it's
233 /// time to do some work.
234 virtual void Schedule() {
235 llvm_unreachable("unimplemented");
240 static ScheduleDAGInstrs *createInstructionShuffler(MachineSchedulerPass *P) {
241 return new InstructionShuffler(P);
243 static MachineSchedRegistry ShufflerRegistry("shuffle",
244 "Shuffle machine instructions",
245 createInstructionShuffler);