[llvm-mca] Move ResourceManager from Scheduler into its own file. NFC.

This time I should be preserving history of the ResourceManager changes.

llvm-svn: 340668

1 files changed, 309 insertions, 0 deletions

diff --git a/llvm/tools/llvm-mca/ResourceManager.cpp b/llvm/tools/llvm-mca/ResourceManager.cpp
new file mode 100644
index 00000000000..80ea73e631d
--- /dev/null
+++ b/llvm/tools/llvm-mca/ResourceManager.cpp
@@ -0,0 +1,309 @@
+//===--------------------- ResourceManager.cpp ------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+///
+/// The classes here represent processor resource units and their management
+/// strategy.  These classes are managed by the Scheduler.
+///
+//===----------------------------------------------------------------------===//
+
+#include "ResourceManager.h"
+#include "Support.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace mca {
+
+using namespace llvm;
+
+#define DEBUG_TYPE "llvm-mca"
+ResourceStrategy::~ResourceStrategy() = default;
+
+void DefaultResourceStrategy::skipMask(uint64_t Mask) {
+  NextInSequenceMask &= (~Mask);
+  if (!NextInSequenceMask) {
+    NextInSequenceMask = ResourceUnitMask ^ RemovedFromNextInSequence;
+    RemovedFromNextInSequence = 0;
+  }
+}
+
+uint64_t DefaultResourceStrategy::select(uint64_t ReadyMask) {
+  // This method assumes that ReadyMask cannot be zero.
+  uint64_t CandidateMask = llvm::PowerOf2Floor(NextInSequenceMask);
+  while (!(ReadyMask & CandidateMask)) {
+    skipMask(CandidateMask);
+    CandidateMask = llvm::PowerOf2Floor(NextInSequenceMask);
+  }
+  return CandidateMask;
+}
+
+void DefaultResourceStrategy::used(uint64_t Mask) {
+  if (Mask > NextInSequenceMask) {
+    RemovedFromNextInSequence |= Mask;
+    return;
+  }
+  skipMask(Mask);
+}
+
+ResourceState::ResourceState(const MCProcResourceDesc &Desc, unsigned Index,
+                             uint64_t Mask)
+    : ProcResourceDescIndex(Index), ResourceMask(Mask),
+      BufferSize(Desc.BufferSize) {
+  if (llvm::countPopulation(ResourceMask) > 1)
+    ResourceSizeMask = ResourceMask ^ llvm::PowerOf2Floor(ResourceMask);
+  else
+    ResourceSizeMask = (1ULL << Desc.NumUnits) - 1;
+  ReadyMask = ResourceSizeMask;
+  AvailableSlots = BufferSize == -1 ? 0U : static_cast<unsigned>(BufferSize);
+  Unavailable = false;
+}
+
+bool ResourceState::isReady(unsigned NumUnits) const {
+  return (!isReserved() || isADispatchHazard()) &&
+         llvm::countPopulation(ReadyMask) >= NumUnits;
+}
+
+ResourceStateEvent ResourceState::isBufferAvailable() const {
+  if (isADispatchHazard() && isReserved())
+    return RS_RESERVED;
+  if (!isBuffered() || AvailableSlots)
+    return RS_BUFFER_AVAILABLE;
+  return RS_BUFFER_UNAVAILABLE;
+}
+
+#ifndef NDEBUG
+void ResourceState::dump() const {
+  dbgs() << "MASK: " << ResourceMask << ", SIZE_MASK: " << ResourceSizeMask
+         << ", RDYMASK: " << ReadyMask << ", BufferSize=" << BufferSize
+         << ", AvailableSlots=" << AvailableSlots
+         << ", Reserved=" << Unavailable << '\n';
+}
+#endif
+
+static unsigned getResourceStateIndex(uint64_t Mask) {
+  return std::numeric_limits<uint64_t>::digits - llvm::countLeadingZeros(Mask);
+}
+
+static std::unique_ptr<ResourceStrategy>
+getStrategyFor(const ResourceState &RS) {
+  if (RS.isAResourceGroup() || RS.getNumUnits() > 1)
+    return llvm::make_unique<DefaultResourceStrategy>(RS.getReadyMask());
+  return std::unique_ptr<ResourceStrategy>(nullptr);
+}
+
+ResourceManager::ResourceManager(const MCSchedModel &SM)
+    : ProcResID2Mask(SM.getNumProcResourceKinds()) {
+  computeProcResourceMasks(SM, ProcResID2Mask);
+  Resources.resize(SM.getNumProcResourceKinds());
+  Strategies.resize(SM.getNumProcResourceKinds());
+
+  for (unsigned I = 0, E = SM.getNumProcResourceKinds(); I < E; ++I) {
+    uint64_t Mask = ProcResID2Mask[I];
+    unsigned Index = getResourceStateIndex(Mask);
+    Resources[Index] =
+        llvm::make_unique<ResourceState>(*SM.getProcResource(I), I, Mask);
+    Strategies[Index] = getStrategyFor(*Resources[Index]);
+  }
+}
+
+void ResourceManager::setCustomStrategyImpl(std::unique_ptr<ResourceStrategy> S,
+                                            uint64_t ResourceMask) {
+  unsigned Index = getResourceStateIndex(ResourceMask);
+  assert(Index < Resources.size() && "Invalid processor resource index!");
+  assert(S && "Unexpected null strategy in input!");
+  Strategies[Index] = std::move(S);
+}
+
+unsigned ResourceManager::resolveResourceMask(uint64_t Mask) const {
+  return Resources[getResourceStateIndex(Mask)]->getProcResourceID();
+}
+
+unsigned ResourceManager::getNumUnits(uint64_t ResourceID) const {
+  return Resources[getResourceStateIndex(ResourceID)]->getNumUnits();
+}
+
+// Returns the actual resource consumed by this Use.
+// First, is the primary resource ID.
+// Second, is the specific sub-resource ID.
+ResourceRef ResourceManager::selectPipe(uint64_t ResourceID) {
+  unsigned Index = getResourceStateIndex(ResourceID);
+  ResourceState &RS = *Resources[Index];
+  assert(RS.isReady() && "No available units to select!");
+
+  // Special case where RS is not a group, and it only declares a single
+  // resource unit.
+  if (!RS.isAResourceGroup() && RS.getNumUnits() == 1)
+    return std::make_pair(ResourceID, RS.getReadyMask());
+
+  uint64_t SubResourceID = Strategies[Index]->select(RS.getReadyMask());
+  if (RS.isAResourceGroup())
+    return selectPipe(SubResourceID);
+  return std::make_pair(ResourceID, SubResourceID);
+}
+
+void ResourceManager::use(const ResourceRef &RR) {
+  // Mark the sub-resource referenced by RR as used.
+  ResourceState &RS = *Resources[getResourceStateIndex(RR.first)];
+  RS.markSubResourceAsUsed(RR.second);
+  // If there are still available units in RR.first,
+  // then we are done.
+  if (RS.isReady())
+    return;
+
+  // Notify to other resources that RR.first is no longer available.
+  for (std::unique_ptr<ResourceState> &Res : Resources) {
+    ResourceState &Current = *Res;
+    if (!Current.isAResourceGroup() || Current.getResourceMask() == RR.first)
+      continue;
+
+    if (Current.containsResource(RR.first)) {
+      unsigned Index = getResourceStateIndex(Current.getResourceMask());
+      Current.markSubResourceAsUsed(RR.first);
+      Strategies[Index]->used(RR.first);
+    }
+  }
+}
+
+void ResourceManager::release(const ResourceRef &RR) {
+  ResourceState &RS = *Resources[getResourceStateIndex(RR.first)];
+  bool WasFullyUsed = !RS.isReady();
+  RS.releaseSubResource(RR.second);
+  if (!WasFullyUsed)
+    return;
+
+  for (std::unique_ptr<ResourceState> &Res : Resources) {
+    ResourceState &Current = *Res;
+    if (!Current.isAResourceGroup() || Current.getResourceMask() == RR.first)
+      continue;
+
+    if (Current.containsResource(RR.first))
+      Current.releaseSubResource(RR.first);
+  }
+}
+
+ResourceStateEvent
+ResourceManager::canBeDispatched(ArrayRef<uint64_t> Buffers) const {
+  ResourceStateEvent Result = ResourceStateEvent::RS_BUFFER_AVAILABLE;
+  for (uint64_t Buffer : Buffers) {
+    ResourceState &RS = *Resources[getResourceStateIndex(Buffer)];
+    Result = RS.isBufferAvailable();
+    if (Result != ResourceStateEvent::RS_BUFFER_AVAILABLE)
+      break;
+  }
+  return Result;
+}
+
+void ResourceManager::reserveBuffers(ArrayRef<uint64_t> Buffers) {
+  for (const uint64_t Buffer : Buffers) {
+    ResourceState &RS = *Resources[getResourceStateIndex(Buffer)];
+    assert(RS.isBufferAvailable() == ResourceStateEvent::RS_BUFFER_AVAILABLE);
+    RS.reserveBuffer();
+
+    if (RS.isADispatchHazard()) {
+      assert(!RS.isReserved());
+      RS.setReserved();
+    }
+  }
+}
+
+void ResourceManager::releaseBuffers(ArrayRef<uint64_t> Buffers) {
+  for (const uint64_t R : Buffers)
+    Resources[getResourceStateIndex(R)]->releaseBuffer();
+}
+
+bool ResourceManager::canBeIssued(const InstrDesc &Desc) const {
+  return std::all_of(Desc.Resources.begin(), Desc.Resources.end(),
+                     [&](const std::pair<uint64_t, const ResourceUsage> &E) {
+                       unsigned NumUnits =
+                           E.second.isReserved() ? 0U : E.second.NumUnits;
+                       unsigned Index = getResourceStateIndex(E.first);
+                       return Resources[Index]->isReady(NumUnits);
+                     });
+}
+
+// Returns true if all resources are in-order, and there is at least one
+// resource which is a dispatch hazard (BufferSize = 0).
+bool ResourceManager::mustIssueImmediately(const InstrDesc &Desc) const {
+  if (!canBeIssued(Desc))
+    return false;
+  bool AllInOrderResources = all_of(Desc.Buffers, [&](uint64_t BufferMask) {
+    unsigned Index = getResourceStateIndex(BufferMask);
+    const ResourceState &Resource = *Resources[Index];
+    return Resource.isInOrder() || Resource.isADispatchHazard();
+  });
+  if (!AllInOrderResources)
+    return false;
+
+  return any_of(Desc.Buffers, [&](uint64_t BufferMask) {
+    return Resources[getResourceStateIndex(BufferMask)]->isADispatchHazard();
+  });
+}
+
+void ResourceManager::issueInstruction(
+    const InstrDesc &Desc,
+    SmallVectorImpl<std::pair<ResourceRef, double>> &Pipes) {
+  for (const std::pair<uint64_t, ResourceUsage> &R : Desc.Resources) {
+    const CycleSegment &CS = R.second.CS;
+    if (!CS.size()) {
+      releaseResource(R.first);
+      continue;
+    }
+
+    assert(CS.begin() == 0 && "Invalid {Start, End} cycles!");
+    if (!R.second.isReserved()) {
+      ResourceRef Pipe = selectPipe(R.first);
+      use(Pipe);
+      BusyResources[Pipe] += CS.size();
+      // Replace the resource mask with a valid processor resource index.
+      const ResourceState &RS = *Resources[getResourceStateIndex(Pipe.first)];
+      Pipe.first = RS.getProcResourceID();
+      Pipes.emplace_back(
+          std::pair<ResourceRef, double>(Pipe, static_cast<double>(CS.size())));
+    } else {
+      assert((countPopulation(R.first) > 1) && "Expected a group!");
+      // Mark this group as reserved.
+      assert(R.second.isReserved());
+      reserveResource(R.first);
+      BusyResources[ResourceRef(R.first, R.first)] += CS.size();
+    }
+  }
+}
+
+void ResourceManager::cycleEvent(SmallVectorImpl<ResourceRef> &ResourcesFreed) {
+  for (std::pair<ResourceRef, unsigned> &BR : BusyResources) {
+    if (BR.second)
+      BR.second--;
+    if (!BR.second) {
+      // Release this resource.
+      const ResourceRef &RR = BR.first;
+
+      if (countPopulation(RR.first) == 1)
+        release(RR);
+
+      releaseResource(RR.first);
+      ResourcesFreed.push_back(RR);
+    }
+  }
+
+  for (const ResourceRef &RF : ResourcesFreed)
+    BusyResources.erase(RF);
+}
+
+void ResourceManager::reserveResource(uint64_t ResourceID) {
+  ResourceState &Resource = *Resources[getResourceStateIndex(ResourceID)];
+  assert(!Resource.isReserved());
+  Resource.setReserved();
+}
+
+void ResourceManager::releaseResource(uint64_t ResourceID) {
+  ResourceState &Resource = *Resources[getResourceStateIndex(ResourceID)];
+  Resource.clearReserved();
+}
+
+} // namespace mca