[MCA] Minor changes to the InOrderIssueStage. NFC

The constructor of InOrderIssueStage no longer takes as input a reference to the
target scheduling model. The stage can always query the subtarget to obtain a
reference to the scheduling model.
The ResourceManager is no longer stored internally as a unique_ptr.
Moved a couple of method definitions to the .cpp file.

include/llvm/MCA/Stages/InOrderIssueStage.h

@@ -11,20 +11,16 @@
 ///
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_MCA_IN_ORDER_ISSUE_STAGE_H
-#define LLVM_MCA_IN_ORDER_ISSUE_STAGE_H
+#ifndef LLVM_MCA_STAGES_INORDERISSUESTAGE_H
+#define LLVM_MCA_STAGES_INORDERISSUESTAGE_H
 
-#include "llvm/ADT/SmallVector.h"
+#include "llvm/MCA/HardwareUnits/ResourceManager.h"
 #include "llvm/MCA/SourceMgr.h"
 #include "llvm/MCA/Stages/Stage.h"
 
 namespace llvm {
-struct MCSchedModel;
-class MCSubtargetInfo;
-
 namespace mca {
 class RegisterFile;
-class ResourceManager;
 
 struct StallInfo {
   enum class StallKind { DEFAULT, REGISTER_DEPS, DISPATCH, DELAY };
@@ -35,41 +31,21 @@ struct StallInfo {
 
   StallInfo() : IR(), CyclesLeft(), Kind(StallKind::DEFAULT) {}
 
-  bool isValid() const { return (bool)IR; }
-
   StallKind getStallKind() const { return Kind; }
   unsigned getCyclesLeft() const { return CyclesLeft; }
   const InstRef &getInstruction() const { return IR; }
   InstRef &getInstruction() { return IR; }
 
-  void clear() {
-    IR.invalidate();
-    CyclesLeft = 0;
-    Kind = StallKind::DEFAULT;
-  }
-
-  void update(const InstRef &Inst, unsigned Cycles, StallKind SK) {
-    IR = Inst;
-    CyclesLeft = Cycles;
-    Kind = SK;
-  }
-
-  void cycleEnd() {
-    if (!isValid())
-      return;
-
-    if (!CyclesLeft)
-      return;
-
-    --CyclesLeft;
-  }
+  bool isValid() const { return (bool)IR; }
+  void clear();
+  void update(const InstRef &Inst, unsigned Cycles, StallKind SK);
+  void cycleEnd();
 };
 
 class InOrderIssueStage final : public Stage {
-  const MCSchedModel &SM;
   const MCSubtargetInfo &STI;
   RegisterFile &PRF;
-  std::unique_ptr<ResourceManager> RM;
+  ResourceManager RM;
 
   /// Instructions that were issued, but not executed yet.
   SmallVector<InstRef, 4> IssuedInst;
@@ -125,11 +101,9 @@ class InOrderIssueStage final : public Stage {
   void retireInstruction(InstRef &IR);
 
 public:
-  InOrderIssueStage(RegisterFile &PRF, const MCSchedModel &SM,
-                    const MCSubtargetInfo &STI)
-      : SM(SM), STI(STI), PRF(PRF), RM(std::make_unique<ResourceManager>(SM)),
-        NumIssued(), SI(), CarryOver(), Bandwidth(), LastWriteBackCycle() {}
+  InOrderIssueStage(const MCSubtargetInfo &STI, RegisterFile &PRF);
 
+  unsigned getIssueWidth() const;
   bool isAvailable(const InstRef &) const override;
   bool hasWorkToComplete() const override;
   Error execute(InstRef &IR) override;
@@ -140,4 +114,4 @@ public:
 } // namespace mca
 } // namespace llvm
 
-#endif // LLVM_MCA_IN_ORDER_ISSUE_STAGE_H
+#endif // LLVM_MCA_STAGES_INORDERISSUESTAGE_H

lib/MCA/Context.cpp

@@ -73,15 +73,17 @@ Context::createInOrderPipeline(const PipelineOptions &Opts, SourceMgr &SrcMgr) {
   const MCSchedModel &SM = STI.getSchedModel();
   auto PRF = std::make_unique<RegisterFile>(SM, MRI, Opts.RegisterFileSize);
 
+  // Create the pipeline stages.
   auto Entry = std::make_unique<EntryStage>(SrcMgr);
-  auto InOrderIssue = std::make_unique<InOrderIssueStage>(*PRF, SM, STI);
-
+  auto InOrderIssue = std::make_unique<InOrderIssueStage>(STI, *PRF);
   auto StagePipeline = std::make_unique<Pipeline>();
-  StagePipeline->appendStage(std::move(Entry));
-  StagePipeline->appendStage(std::move(InOrderIssue));
 
+  // Pass the ownership of all the hardware units to this Context.
   addHardwareUnit(std::move(PRF));
 
+  // Build the pipeline.
+  StagePipeline->appendStage(std::move(Entry));
+  StagePipeline->appendStage(std::move(InOrderIssue));
   return StagePipeline;
 }
 

lib/MCA/Stages/InOrderIssueStage.cpp

@@ -13,7 +13,6 @@
 
 #include "llvm/MCA/Stages/InOrderIssueStage.h"
 #include "llvm/MCA/HardwareUnits/RegisterFile.h"
-#include "llvm/MCA/HardwareUnits/ResourceManager.h"
 #include "llvm/MCA/HardwareUnits/RetireControlUnit.h"
 #include "llvm/MCA/Instruction.h"
 
@@ -21,6 +20,37 @@
 namespace llvm {
 namespace mca {
 
+void StallInfo::clear() {
+  IR.invalidate();
+  CyclesLeft = 0;
+  Kind = StallKind::DEFAULT;
+}
+
+void StallInfo::update(const InstRef &Inst, unsigned Cycles, StallKind SK) {
+  IR = Inst;
+  CyclesLeft = Cycles;
+  Kind = SK;
+}
+
+void StallInfo::cycleEnd() {
+  if (!isValid())
+    return;
+
+  if (!CyclesLeft)
+    return;
+
+  --CyclesLeft;
+}
+
+InOrderIssueStage::InOrderIssueStage(const MCSubtargetInfo &STI,
+                                     RegisterFile &PRF)
+    : STI(STI), PRF(PRF), RM(STI.getSchedModel()), NumIssued(), SI(),
+      CarryOver(), Bandwidth(), LastWriteBackCycle() {}
+
+unsigned InOrderIssueStage::getIssueWidth() const {
+  return STI.getSchedModel().IssueWidth;
+}
+
 bool InOrderIssueStage::hasWorkToComplete() const {
   return !IssuedInst.empty() || SI.isValid() || CarriedOver;
 }
@@ -33,7 +63,7 @@ bool InOrderIssueStage::isAvailable(const InstRef &IR) const {
   unsigned NumMicroOps = Inst.getNumMicroOps();
   const InstrDesc &Desc = Inst.getDesc();
 
-  bool ShouldCarryOver = NumMicroOps > SM.IssueWidth;
+  bool ShouldCarryOver = NumMicroOps > getIssueWidth();
   if (Bandwidth < NumMicroOps && !ShouldCarryOver)
     return false;
 
@@ -90,7 +120,7 @@ bool InOrderIssueStage::canExecute(const InstRef &IR) {
     return false;
   }
 
-  if (hasResourceHazard(*RM, IR)) {
+  if (hasResourceHazard(RM, IR)) {
     SI.update(IR, /* delay */ 1, StallInfo::StallKind::DISPATCH);
     return false;
   }
@@ -184,13 +214,13 @@ llvm::Error InOrderIssueStage::tryIssue(InstRef &IR) {
   notifyInstructionDispatched(IR, NumMicroOps, UsedRegs);
 
   SmallVector<ResourceUse, 4> UsedResources;
-  RM->issueInstruction(Desc, UsedResources);
+  RM.issueInstruction(Desc, UsedResources);
   IS.execute(SourceIndex);
 
   // Replace resource masks with valid resource processor IDs.
   for (ResourceUse &Use : UsedResources) {
     uint64_t Mask = Use.first.first;
-    Use.first.first = RM->resolveResourceMask(Mask);
+    Use.first.first = RM.resolveResourceMask(Mask);
   }
   notifyInstructionIssued(IR, UsedResources);
 
@@ -308,13 +338,13 @@ void InOrderIssueStage::notifyStallEvent() {
 
 llvm::Error InOrderIssueStage::cycleStart() {
   NumIssued = 0;
-  Bandwidth = SM.IssueWidth;
+  Bandwidth = getIssueWidth();
 
   PRF.cycleStart();
 
   // Release consumed resources.
   SmallVector<ResourceRef, 4> Freed;
-  RM->cycleEvent(Freed);
+  RM.cycleEvent(Freed);
 
   updateIssuedInst();
 
@@ -343,7 +373,7 @@ llvm::Error InOrderIssueStage::cycleStart() {
     }
   }
 
-  assert(NumIssued <= SM.IssueWidth && "Overflow.");
+  assert((NumIssued <= getIssueWidth()) && "Overflow.");
   return llvm::ErrorSuccess();
 }