[NFC][TableGen] Cleanup iterators in CodeGenSchedule.h

[jurahul]

• Use range for loops for processor models and schedule classes.
• Cleanup duplicated or unused iterators in CodeGenSchedule.h

[llvmbot]

@llvm/pr-subscribers-tablegen

Author: Rahul Joshi (jurahul)

Changes

• Use range for loops for iterating over processor models and schedule classes.
• Cleanup duplicated or unused iterators in CodeGenSchedule.h

---

Full diff: https://github.com/llvm/llvm-project/pull/127401.diff

3 Files Affected:

• (modified) llvm/utils/TableGen/Common/CodeGenSchedule.h (+5-26)
• (modified) llvm/utils/TableGen/InstrInfoEmitter.cpp (+1-1)
• (modified) llvm/utils/TableGen/SubtargetEmitter.cpp (+36-52)

diff --git a/llvm/utils/TableGen/Common/CodeGenSchedule.h b/llvm/utils/TableGen/Common/CodeGenSchedule.h
index 981782c17c48c..8343257b458dd 100644
--- a/llvm/utils/TableGen/Common/CodeGenSchedule.h
+++ b/llvm/utils/TableGen/Common/CodeGenSchedule.h
@@ -467,23 +467,6 @@ class CodeGenSchedModels {
 public:
   CodeGenSchedModels(const RecordKeeper &RK, const CodeGenTarget &TGT);
 
-  // iterator access to the scheduling classes.
-  using class_iterator = std::vector<CodeGenSchedClass>::iterator;
-  using const_class_iterator = std::vector<CodeGenSchedClass>::const_iterator;
-  class_iterator classes_begin() { return SchedClasses.begin(); }
-  const_class_iterator classes_begin() const { return SchedClasses.begin(); }
-  class_iterator classes_end() { return SchedClasses.end(); }
-  const_class_iterator classes_end() const { return SchedClasses.end(); }
-  iterator_range<class_iterator> classes() {
-    return make_range(classes_begin(), classes_end());
-  }
-  iterator_range<const_class_iterator> classes() const {
-    return make_range(classes_begin(), classes_end());
-  }
-  ArrayRef<CodeGenSchedClass> explicit_classes() const {
-    return ArrayRef(SchedClasses).take_front(NumInstrSchedClasses);
-  }
-
   const Record *getModelOrItinDef(const Record *ProcDef) const {
     const Record *ModelDef = ProcDef->getValueAsDef("SchedModel");
     const Record *ItinsDef = ProcDef->getValueAsDef("ProcItin");
@@ -497,13 +480,13 @@ class CodeGenSchedModels {
 
   const CodeGenProcModel &getModelForProc(const Record *ProcDef) const {
     const Record *ModelDef = getModelOrItinDef(ProcDef);
-    ProcModelMapTy::const_iterator I = ProcModelMap.find(ModelDef);
+    auto I = ProcModelMap.find(ModelDef);
     assert(I != ProcModelMap.end() && "missing machine model");
     return ProcModels[I->second];
   }
 
   const CodeGenProcModel &getProcModel(const Record *ModelDef) const {
-    ProcModelMapTy::const_iterator I = ProcModelMap.find(ModelDef);
+    auto I = ProcModelMap.find(ModelDef);
     assert(I != ProcModelMap.end() && "missing machine model");
     return ProcModels[I->second];
   }
@@ -512,10 +495,6 @@ class CodeGenSchedModels {
         static_cast<const CodeGenSchedModels &>(*this).getProcModel(ModelDef));
   }
 
-  // Iterate over the unique processor models.
-  using ProcIter = std::vector<CodeGenProcModel>::const_iterator;
-  ProcIter procModelBegin() const { return ProcModels.begin(); }
-  ProcIter procModelEnd() const { return ProcModels.end(); }
   ArrayRef<CodeGenProcModel> procModels() const { return ProcModels; }
 
   // Return true if any processors have itineraries.
@@ -564,10 +543,10 @@ class CodeGenSchedModels {
   // for NoItinerary.
   unsigned getSchedClassIdx(const CodeGenInstruction &Inst) const;
 
-  using SchedClassIter = std::vector<CodeGenSchedClass>::const_iterator;
-  SchedClassIter schedClassBegin() const { return SchedClasses.begin(); }
-  SchedClassIter schedClassEnd() const { return SchedClasses.end(); }
   ArrayRef<CodeGenSchedClass> schedClasses() const { return SchedClasses; }
+  ArrayRef<CodeGenSchedClass> explicitSchedClasses() const {
+    return schedClasses().take_front(NumInstrSchedClasses);
+  }
 
   unsigned numInstrSchedClasses() const { return NumInstrSchedClasses; }
 
diff --git a/llvm/utils/TableGen/InstrInfoEmitter.cpp b/llvm/utils/TableGen/InstrInfoEmitter.cpp
index 3ea76ed414d91..377bfb593be5f 100644
--- a/llvm/utils/TableGen/InstrInfoEmitter.cpp
+++ b/llvm/utils/TableGen/InstrInfoEmitter.cpp
@@ -1244,7 +1244,7 @@ void InstrInfoEmitter::emitEnums(
   OS << "#undef GET_INSTRINFO_SCHED_ENUM\n";
   OS << "namespace llvm::" << Namespace << "::Sched {\n\n";
   OS << "  enum {\n";
-  auto ExplictClasses = SchedModels.explicit_classes();
+  auto ExplictClasses = SchedModels.explicitSchedClasses();
   for (const auto &[Idx, Class] : enumerate(ExplictClasses))
     OS << "    " << Class.Name << "\t= " << Idx << ",\n";
   OS << "    SCHED_LIST_END = " << ExplictClasses.size() << '\n';
diff --git a/llvm/utils/TableGen/SubtargetEmitter.cpp b/llvm/utils/TableGen/SubtargetEmitter.cpp
index 49362ff5ef655..c54e00cdb0ce1 100644
--- a/llvm/utils/TableGen/SubtargetEmitter.cpp
+++ b/llvm/utils/TableGen/SubtargetEmitter.cpp
@@ -106,7 +106,7 @@ class SubtargetEmitter {
   void emitStageAndOperandCycleData(
       raw_ostream &OS, std::vector<std::vector<InstrItinerary>> &ProcItinLists);
   void emitItineraries(raw_ostream &OS,
-                       std::vector<std::vector<InstrItinerary>> &ProcItinLists);
+                       ArrayRef<std::vector<InstrItinerary>> ProcItinLists);
   unsigned emitRegisterFileTables(const CodeGenProcModel &ProcModel,
                                   raw_ostream &OS);
   void emitLoadStoreQueueInfo(const CodeGenProcModel &ProcModel,
@@ -477,7 +477,6 @@ void SubtargetEmitter::emitStageAndOperandCycleData(
 
   // Emit functional units for all the itineraries.
   for (const CodeGenProcModel &ProcModel : SchedModels.procModels()) {
-
     if (!ItinsDefSet.insert(ProcModel.ItinsDef).second)
       continue;
 
@@ -489,25 +488,23 @@ void SubtargetEmitter::emitStageAndOperandCycleData(
     OS << "\n// Functional units for \"" << Name << "\"\n"
        << "namespace " << Name << "FU {\n";
 
-    for (unsigned J = 0, FUN = FUs.size(); J < FUN; ++J)
-      OS << "  const InstrStage::FuncUnits " << FUs[J]->getName()
-         << " = 1ULL << " << J << ";\n";
+    for (const auto &[Idx, FU] : enumerate(FUs))
+      OS << "  const InstrStage::FuncUnits " << FU->getName() << " = 1ULL << "
+         << Idx << ";\n";
 
     OS << "} // end namespace " << Name << "FU\n";
 
     ConstRecVec BPs = ProcModel.ItinsDef->getValueAsListOfDefs("BP");
-    if (!BPs.empty()) {
-      OS << "\n// Pipeline forwarding paths for itineraries \"" << Name
-         << "\"\n"
-         << "namespace " << Name << "Bypass {\n";
+    if (BPs.empty())
+      continue;
+    OS << "\n// Pipeline forwarding paths for itineraries \"" << Name << "\"\n"
+       << "namespace " << Name << "Bypass {\n";
 
-      OS << "  const unsigned NoBypass = 0;\n";
-      for (unsigned J = 0, BPN = BPs.size(); J < BPN; ++J)
-        OS << "  const unsigned " << BPs[J]->getName() << " = 1 << " << J
-           << ";\n";
+    OS << "  const unsigned NoBypass = 0;\n";
+    for (const auto &[Idx, BP] : enumerate(BPs))
+      OS << "  const unsigned " << BP->getName() << " = 1 << " << Idx << ";\n";
 
-      OS << "} // end namespace " << Name << "Bypass\n";
-    }
+    OS << "} // end namespace " << Name << "Bypass\n";
   }
 
   // Begin stages table
@@ -647,46 +644,39 @@ void SubtargetEmitter::emitStageAndOperandCycleData(
 // CodeGenSchedClass::Index.
 //
 void SubtargetEmitter::emitItineraries(
-    raw_ostream &OS, std::vector<std::vector<InstrItinerary>> &ProcItinLists) {
+    raw_ostream &OS, ArrayRef<std::vector<InstrItinerary>> ProcItinLists) {
   // Multiple processor models may share an itinerary record. Emit it once.
   SmallPtrSet<const Record *, 8> ItinsDefSet;
 
-  // For each processor's machine model
-  std::vector<std::vector<InstrItinerary>>::iterator ProcItinListsIter =
-      ProcItinLists.begin();
-  for (CodeGenSchedModels::ProcIter PI = SchedModels.procModelBegin(),
-                                    PE = SchedModels.procModelEnd();
-       PI != PE; ++PI, ++ProcItinListsIter) {
-
-    const Record *ItinsDef = PI->ItinsDef;
+  for (const auto &[Proc, ItinList] :
+       zip_equal(SchedModels.procModels(), ProcItinLists)) {
+    const Record *ItinsDef = Proc.ItinsDef;
     if (!ItinsDefSet.insert(ItinsDef).second)
       continue;
 
-    // Get the itinerary list for the processor.
-    assert(ProcItinListsIter != ProcItinLists.end() && "bad iterator");
-    std::vector<InstrItinerary> &ItinList = *ProcItinListsIter;
-
     // Empty itineraries aren't referenced anywhere in the tablegen output
     // so don't emit them.
     if (ItinList.empty())
       continue;
 
+    // Begin processor itinerary table
     OS << "\n";
-    OS << "static const llvm::InstrItinerary ";
+    OS << "static constexpr llvm::InstrItinerary " << ItinsDef->getName()
+       << "[] = {\n";
 
-    // Begin processor itinerary table
-    OS << ItinsDef->getName() << "[] = {\n";
+    ArrayRef<CodeGenSchedClass> ItinSchedClasses =
+        SchedModels.schedClasses().take_front(ItinList.size());
 
     // For each itinerary class in CodeGenSchedClass::Index order.
-    for (unsigned J = 0, M = ItinList.size(); J < M; ++J) {
-      InstrItinerary &Intinerary = ItinList[J];
-
+    for (const auto &[Idx, Intinerary, SchedClass] :
+         enumerate(ItinList, ItinSchedClasses)) {
       // Emit Itinerary in the form of
-      // { firstStage, lastStage, firstCycle, lastCycle } // index
+      // { NumMicroOps, FirstStage, LastStage, FirstOperandCycle,
+      // LastOperandCycle } // index class name
       OS << "  { " << Intinerary.NumMicroOps << ", " << Intinerary.FirstStage
          << ", " << Intinerary.LastStage << ", " << Intinerary.FirstOperandCycle
-         << ", " << Intinerary.LastOperandCycle << " }"
-         << ", // " << J << " " << SchedModels.getSchedClass(J).Name << "\n";
+         << ", " << Intinerary.LastOperandCycle << " }" << ", // " << Idx << " "
+         << SchedClass.Name << "\n";
     }
     // End processor itinerary table
     OS << "  { 0, uint16_t(~0U), uint16_t(~0U), uint16_t(~0U), uint16_t(~0U) }"
@@ -1438,18 +1428,16 @@ void SubtargetEmitter::emitSchedClassTables(SchedClassTables &SchedTables,
   OS << "}; // " << Target << "ReadAdvanceTable\n";
 
   // Emit a SchedClass table for each processor.
-  for (CodeGenSchedModels::ProcIter PI = SchedModels.procModelBegin(),
-                                    PE = SchedModels.procModelEnd();
-       PI != PE; ++PI) {
-    if (!PI->hasInstrSchedModel())
+  for (const auto &[Idx, Proc] : enumerate(SchedModels.procModels())) {
+    if (!Proc.hasInstrSchedModel())
       continue;
 
     std::vector<MCSchedClassDesc> &SCTab =
-        SchedTables.ProcSchedClasses[1 + (PI - SchedModels.procModelBegin())];
+        SchedTables.ProcSchedClasses[1 + Idx];
 
     OS << "\n// {Name, NumMicroOps, BeginGroup, EndGroup, RetireOOO,"
        << " WriteProcResIdx,#, WriteLatencyIdx,#, ReadAdvanceIdx,#}\n";
-    OS << "static const llvm::MCSchedClassDesc " << PI->ModelName
+    OS << "static const llvm::MCSchedClassDesc " << Proc.ModelName
        << "SchedClasses[] = {\n";
 
     // The first class is always invalid. We no way to distinguish it except by
@@ -1476,7 +1464,7 @@ void SubtargetEmitter::emitSchedClassTables(SchedClassTables &SchedTables,
          << format("%2d", MCDesc.ReadAdvanceIdx) << ", "
          << MCDesc.NumReadAdvanceEntries << "}, // #" << SCIdx << '\n';
     }
-    OS << "}; // " << PI->ModelName << "SchedClasses\n";
+    OS << "}; // " << Proc.ModelName << "SchedClasses\n";
   }
 }
 
@@ -1524,14 +1512,10 @@ void SubtargetEmitter::emitProcessorModels(raw_ostream &OS) {
 
     OS << "  " << PM.Index << ", // Processor ID\n";
     if (PM.hasInstrSchedModel())
-      OS << "  " << PM.ModelName << "ProcResources"
-         << ",\n"
-         << "  " << PM.ModelName << "SchedClasses"
-         << ",\n"
+      OS << "  " << PM.ModelName << "ProcResources" << ",\n"
+         << "  " << PM.ModelName << "SchedClasses" << ",\n"
          << "  " << PM.ProcResourceDefs.size() + 1 << ",\n"
-         << "  "
-         << (SchedModels.schedClassEnd() - SchedModels.schedClassBegin())
-         << ",\n";
+         << "  " << SchedModels.schedClasses().size() << ",\n";
     else
       OS << "  nullptr, nullptr, 0, 0,"
          << " // No instruction-level machine model.\n";
@@ -1743,7 +1727,7 @@ void SubtargetEmitter::emitSchedModelHelpersImpl(
                    ? "if (CPUID == "
                    : "if (SchedModel->getProcessorID() == ");
         OS << PI << ") ";
-        OS << "{ // " << (SchedModels.procModelBegin() + PI)->ModelName << '\n';
+        OS << "{ // " << SchedModels.procModels()[PI].ModelName << '\n';
       }
 
       // Now emit transitions associated with processor PI.

[topperc]

LGTM