Added the MachineSchedulerPass skeleton.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148105 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/Passes.h

@@ -84,6 +84,9 @@ namespace llvm {
   /// RegisteCoalescer pass - This pass merges live ranges to eliminate copies.
   extern char &RegisterCoalescerPassID;
 
+  /// MachineScheduler pass - This pass schedules machine instructions.
+  extern char &MachineSchedulerPassID;
+
   /// SpillPlacement analysis. Suggest optimal placement of spill code between
   /// basic blocks.
   ///

include/llvm/InitializePasses.h

@@ -156,6 +156,7 @@ void initializeMachineLICMPass(PassRegistry&);
 void initializeMachineLoopInfoPass(PassRegistry&);
 void initializeMachineLoopRangesPass(PassRegistry&);
 void initializeMachineModuleInfoPass(PassRegistry&);
+void initializeMachineSchedulerPassPass(PassRegistry&);
 void initializeMachineSinkingPass(PassRegistry&);
 void initializeMachineVerifierPassPass(PassRegistry&);
 void initializeMemCpyOptPass(PassRegistry&);

include/llvm/Target/TargetOptions.h

@@ -34,6 +34,10 @@ namespace llvm {
   /// wth earlier copy coalescing.
   extern bool StrongPHIElim;
 
+  /// EnableMachineSched - temporary flag to enable the machine scheduling pass
+  /// until we complete the register allocation pass configuration cleanup.
+  extern bool EnableMachineSched;
+
   class TargetOptions {
   public:
     TargetOptions()

lib/CodeGen/CMakeLists.txt

@@ -57,6 +57,7 @@ add_llvm_library(LLVMCodeGen
   MachinePassRegistry.cpp
   MachineRegisterInfo.cpp
   MachineSSAUpdater.cpp
+  MachineScheduler.cpp
   MachineSink.cpp
   MachineVerifier.cpp
   OcamlGC.cpp

lib/CodeGen/CodeGen.cpp

@@ -43,6 +43,7 @@ void llvm::initializeCodeGen(PassRegistry &Registry) {
   initializeProcessImplicitDefsPass(Registry);
   initializePEIPass(Registry);
   initializeRegisterCoalescerPass(Registry);
+  initializeMachineSchedulerPassPass(Registry);
   initializeRenderMachineFunctionPass(Registry);
   initializeSlotIndexesPass(Registry);
   initializeStackProtectorPass(Registry);

lib/CodeGen/MachineScheduler.cpp

@@ -0,0 +1,233 @@
+//===- MachineScheduler.cpp - Machine Instruction Scheduler ---------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// MachineScheduler schedules machine instructions after phi elimination. It
+// preserves LiveIntervals so it can be invoked before register allocation.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "misched"
+
+#include "ScheduleDAGInstrs.h"
+#include "LiveDebugVariables.h"
+#include "llvm/CodeGen/LiveIntervalAnalysis.h"
+#include "llvm/CodeGen/MachinePassRegistry.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/ADT/OwningPtr.h"
+
+using namespace llvm;
+
+namespace {
+/// MachineSchedulerPass runs after coalescing and before register allocation.
+class MachineSchedulerPass : public MachineFunctionPass {
+public:
+  MachineFunction *MF;
+  const MachineLoopInfo *MLI;
+  const MachineDominatorTree *MDT;
+
+  MachineSchedulerPass();
+
+  virtual void getAnalysisUsage(AnalysisUsage &AU) const;
+
+  virtual void releaseMemory() {}
+
+  virtual bool runOnMachineFunction(MachineFunction&);
+
+  virtual void print(raw_ostream &O, const Module* = 0) const;
+
+  static char ID; // Class identification, replacement for typeinfo
+};
+} // namespace
+
+char MachineSchedulerPass::ID = 0;
+
+char &llvm::MachineSchedulerPassID = MachineSchedulerPass::ID;
+
+INITIALIZE_PASS_BEGIN(MachineSchedulerPass, "misched",
+                      "Machine Instruction Scheduler", false, false)
+INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
+INITIALIZE_PASS_DEPENDENCY(SlotIndexes)
+INITIALIZE_PASS_DEPENDENCY(LiveIntervals)
+INITIALIZE_PASS_DEPENDENCY(LiveDebugVariables)
+INITIALIZE_PASS_DEPENDENCY(StrongPHIElimination)
+INITIALIZE_PASS_DEPENDENCY(RegisterCoalescer)
+INITIALIZE_PASS_END(MachineSchedulerPass, "misched",
+                    "Machine Instruction Scheduler", false, false)
+
+MachineSchedulerPass::MachineSchedulerPass()
+: MachineFunctionPass(ID), MF(0), MLI(0), MDT(0) {
+  initializeMachineSchedulerPassPass(*PassRegistry::getPassRegistry());
+}
+
+void MachineSchedulerPass::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.setPreservesCFG();
+  AU.addRequiredID(MachineDominatorsID);
+  AU.addRequired<MachineLoopInfo>();
+  AU.addRequired<AliasAnalysis>();
+  AU.addPreserved<AliasAnalysis>();
+  AU.addRequired<SlotIndexes>();
+  AU.addPreserved<SlotIndexes>();
+  AU.addRequired<LiveIntervals>();
+  AU.addPreserved<LiveIntervals>();
+  AU.addRequired<LiveDebugVariables>();
+  AU.addPreserved<LiveDebugVariables>();
+  if (StrongPHIElim) {
+    AU.addRequiredID(StrongPHIEliminationID);
+    AU.addPreservedID(StrongPHIEliminationID);
+  }
+  AU.addRequiredID(RegisterCoalescerPassID);
+  AU.addPreservedID(RegisterCoalescerPassID);
+  MachineFunctionPass::getAnalysisUsage(AU);
+}
+
+namespace {
+/// Currently force DAG building but don't reschedule anything.  This is a
+/// temporarily useful framework that provides a place to hook in experimental
+/// code that requires a dependence graph prior to register allocation.
+class MachineScheduler : public ScheduleDAGInstrs {
+public:
+  MachineScheduler(MachineSchedulerPass *P)
+    : ScheduleDAGInstrs(*P->MF, *P->MLI, *P->MDT)
+  {}
+
+  /// Schedule - This is called back from ScheduleDAGInstrs::Run() when it's
+  /// time to do some work.
+  virtual void Schedule();
+};
+} // namespace
+
+namespace {
+/// MachineSchedRegistry provides a selection of available machine instruction
+/// schedulers.
+class MachineSchedRegistry : public MachinePassRegistryNode {
+public:
+  typedef ScheduleDAGInstrs *(*ScheduleDAGCtor)(MachineSchedulerPass *);
+
+  // RegisterPassParser requires a (misnamed) FunctionPassCtor type.
+  typedef ScheduleDAGCtor FunctionPassCtor;
+
+  static MachinePassRegistry Registry;
+
+  MachineSchedRegistry(const char *N, const char *D, ScheduleDAGCtor C)
+    : MachinePassRegistryNode(N, D, (MachinePassCtor)C) {
+    Registry.Add(this);
+  }
+  ~MachineSchedRegistry() { Registry.Remove(this); }
+
+  // Accessors.
+  //
+  MachineSchedRegistry *getNext() const {
+    return (MachineSchedRegistry *)MachinePassRegistryNode::getNext();
+  }
+  static MachineSchedRegistry *getList() {
+    return (MachineSchedRegistry *)Registry.getList();
+  }
+  static ScheduleDAGCtor getDefault() {
+    return (ScheduleDAGCtor)Registry.getDefault();
+  }
+  static void setDefault(ScheduleDAGCtor C) {
+    Registry.setDefault((MachinePassCtor)C);
+  }
+  static void setListener(MachinePassRegistryListener *L) {
+    Registry.setListener(L);
+  }
+};
+} // namespace
+
+MachinePassRegistry MachineSchedRegistry::Registry;
+
+static ScheduleDAGInstrs *createDefaultMachineSched(MachineSchedulerPass *P);
+
+/// MachineSchedOpt allows command line selection of the scheduler.
+static cl::opt<MachineSchedRegistry::ScheduleDAGCtor, false,
+               RegisterPassParser<MachineSchedRegistry> >
+MachineSchedOpt("misched",
+                cl::init(&createDefaultMachineSched), cl::Hidden,
+                cl::desc("Machine instruction scheduler to use"));
+
+static ScheduleDAGInstrs *createDefaultMachineSched(MachineSchedulerPass *P) {
+  return new MachineScheduler(P);
+}
+static MachineSchedRegistry
+SchedDefaultRegistry("default", "Activate the scheduler pass, "
+                     "but don't reorder instructions",
+                     createDefaultMachineSched);
+
+/// Schedule - This is called back from ScheduleDAGInstrs::Run() when it's
+/// time to do some work.
+void MachineScheduler::Schedule() {
+  DEBUG(dbgs() << "********** MI Scheduling **********\n");
+  DEBUG(for (unsigned su = 0, e = SUnits.size(); su != e; ++su)
+          SUnits[su].dumpAll(this));
+  // TODO: Put interesting things here.
+}
+
+bool MachineSchedulerPass::runOnMachineFunction(MachineFunction &mf) {
+  // Initialize the context of the pass.
+  MF = &mf;
+  MLI = &getAnalysis<MachineLoopInfo>();
+  MDT = &getAnalysis<MachineDominatorTree>();
+
+  // Select the scheduler, or set the default.
+  MachineSchedRegistry::ScheduleDAGCtor Ctor =
+    MachineSchedRegistry::getDefault();
+  if (!Ctor) {
+    Ctor = MachineSchedOpt;
+    MachineSchedRegistry::setDefault(Ctor);
+  }
+  // Instantiate the selected scheduler.
+  OwningPtr<ScheduleDAGInstrs> Scheduler(Ctor(this));
+
+  // Visit all machine basic blocks.
+  for (MachineFunction::iterator MBB = MF->begin(), MBBEnd = MF->end();
+       MBB != MBBEnd; ++MBB) {
+
+    DEBUG(dbgs() << "MachineScheduling " << MF->getFunction()->getName()
+          << ":BB#" << MBB->getNumber() << "\n");
+
+    // Inform ScheduleDAGInstrs of the region being scheduler. It calls back
+    // to our Schedule() method.
+    Scheduler->Run(MBB, MBB->begin(), MBB->end(), MBB->size());
+  }
+  return true;
+}
+
+void MachineSchedulerPass::print(raw_ostream &O, const Module* m) const {
+  // unimplemented
+}
+
+#ifndef NDEBUG
+namespace {
+/// Reorder instructions as much as possible.
+class InstructionShuffler : public ScheduleDAGInstrs {
+public:
+  InstructionShuffler(MachineSchedulerPass *P)
+    : ScheduleDAGInstrs(*P->MF, *P->MLI, *P->MDT)
+  {}
+
+  /// Schedule - This is called back from ScheduleDAGInstrs::Run() when it's
+  /// time to do some work.
+  virtual void Schedule() {
+    llvm_unreachable("unimplemented");
+  }
+};
+} // namespace
+
+static ScheduleDAGInstrs *createInstructionShuffler(MachineSchedulerPass *P) {
+  return new InstructionShuffler(P);
+}
+static MachineSchedRegistry ShufflerRegistry("shuffle",
+                                             "Shuffle machine instructions",
+                                             createInstructionShuffler);
+#endif // !NDEBUG

lib/CodeGen/RegAllocBasic.cpp

@@ -129,6 +129,7 @@ RABasic::RABasic(): MachineFunctionPass(ID) {
   initializeSlotIndexesPass(*PassRegistry::getPassRegistry());
   initializeStrongPHIEliminationPass(*PassRegistry::getPassRegistry());
   initializeRegisterCoalescerPass(*PassRegistry::getPassRegistry());
+  initializeMachineSchedulerPassPass(*PassRegistry::getPassRegistry());
   initializeCalculateSpillWeightsPass(*PassRegistry::getPassRegistry());
   initializeLiveStacksPass(*PassRegistry::getPassRegistry());
   initializeMachineDominatorTreePass(*PassRegistry::getPassRegistry());
@@ -148,6 +149,8 @@ void RABasic::getAnalysisUsage(AnalysisUsage &AU) const {
   if (StrongPHIElim)
     AU.addRequiredID(StrongPHIEliminationID);
   AU.addRequiredTransitiveID(RegisterCoalescerPassID);
+  if (EnableMachineSched)
+    AU.addRequiredID(MachineSchedulerPassID);
   AU.addRequired<CalculateSpillWeights>();
   AU.addRequired<LiveStacks>();
   AU.addPreserved<LiveStacks>();

lib/CodeGen/RegAllocGreedy.cpp

@@ -309,6 +309,7 @@ RAGreedy::RAGreedy(): MachineFunctionPass(ID) {
   initializeSlotIndexesPass(*PassRegistry::getPassRegistry());
   initializeStrongPHIEliminationPass(*PassRegistry::getPassRegistry());
   initializeRegisterCoalescerPass(*PassRegistry::getPassRegistry());
+  initializeMachineSchedulerPassPass(*PassRegistry::getPassRegistry());
   initializeCalculateSpillWeightsPass(*PassRegistry::getPassRegistry());
   initializeLiveStacksPass(*PassRegistry::getPassRegistry());
   initializeMachineDominatorTreePass(*PassRegistry::getPassRegistry());
@@ -330,6 +331,8 @@ void RAGreedy::getAnalysisUsage(AnalysisUsage &AU) const {
   if (StrongPHIElim)
     AU.addRequiredID(StrongPHIEliminationID);
   AU.addRequiredTransitiveID(RegisterCoalescerPassID);
+  if (EnableMachineSched)
+    AU.addRequiredID(MachineSchedulerPassID);
   AU.addRequired<CalculateSpillWeights>();
   AU.addRequired<LiveStacks>();
   AU.addPreserved<LiveStacks>();

lib/Target/TargetMachine.cpp

@@ -23,6 +23,7 @@ using namespace llvm;
 
 namespace llvm {
   bool StrongPHIElim;
+  bool EnableMachineSched;
   bool HasDivModLibcall;
   bool AsmVerbosityDefault(false);
 }
@@ -35,7 +36,15 @@ static cl::opt<bool>
 FunctionSections("ffunction-sections",
   cl::desc("Emit functions into separate sections"),
   cl::init(false));
-                         
+
+/// EnableMachineSched - temporary flag to enable the machine scheduling pass
+/// until we complete the register allocation pass configuration cleanup.
+static cl::opt<bool, true>
+MachineSchedOpt("enable-misched",
+                cl::desc("Enable the machine instruction scheduling pass."),
+                cl::location(EnableMachineSched),
+                cl::init(false), cl::Hidden);
+
 //---------------------------------------------------------------------------
 // TargetMachine Class
 //