Remove the now usused ConformanceCollector utility.

It was used for dead witness table elimination. But this is done now by lazy emission in IRGen.
Also update DeadFunctionElimination.
NFC.

Author: eeckstein

include/swift/SIL/InstructionUtils.h

@@ -14,13 +14,9 @@
 #define SWIFT_SIL_INSTRUCTIONUTILS_H
 
 #include "swift/SIL/SILInstruction.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/SmallPtrSet.h"
 
 namespace swift {
 
-class SILWitnessTable;
-
 /// Strip off casts/indexing insts/address projections from V until there is
 /// nothing left to strip.
 SILValue getUnderlyingObject(SILValue V);
@@ -77,99 +73,6 @@ SILValue stripIndexingInsts(SILValue V);
 /// intrinsic call.
 SILValue stripExpectIntrinsic(SILValue V);
 
-/// Collects conformances which are used by instructions or inside witness
-/// tables.
-///
-/// It also collects "escaping" metatypes. If a metatype can escape to a not
-/// visible function (outside the compilation unit), all it's conformances have
-/// to be alive, because an opaque type can be tested at runtime if it conforms
-/// to a protocol.
-class ConformanceCollector {
-  /// The used conformances.
-  llvm::SmallVector<const ProtocolConformance *, 8> Conformances;
-
-  /// Types of which metatypes are escaping.
-  llvm::SmallVector<const NominalTypeDecl *, 8> EscapingMetaTypes;
-
-  /// Conformances and types which have been handled.
-  llvm::SmallPtrSet<const void *, 8> Visited;
-
-  SILModule &M;
-
-  void scanType(Type type);
-  void scanSubsts(SubstitutionList substs);
-
-  template <typename T> void scanFuncParams(ArrayRef<T> OrigParams,
-                                            ArrayRef<T> SubstParams) {
-    size_t NumParams = OrigParams.size();
-    assert(NumParams == SubstParams.size());
-    for (size_t Idx = 0; Idx < NumParams; ++Idx) {
-      if (OrigParams[Idx].getType()->hasTypeParameter()) {
-        scanType(SubstParams[Idx].getType());
-      }
-    }
-  }
-
-  void scanConformance(ProtocolConformance *C);
-
-  void scanConformance(ProtocolConformanceRef CRef) {
-    if (CRef.isConcrete())
-      scanConformance(CRef.getConcrete());
-  }
-
-  void scanConformances(ArrayRef<ProtocolConformanceRef> CRefs);
-
-public:
-
-  ConformanceCollector(SILModule &M) : M(M) { }
-
-#ifndef NDEBUG
-  static bool verifyInIRGen() {
-    // TODO: currently disabled because of several problems.
-    return false;
-  }
-#endif
-
-  /// Collect all used conformances of an instruction.
-  ///
-  /// If the instruction can escape a metatype, also record this metatype.
-  void collect(SILInstruction *I);
-
-  /// Collect all used conformances and metatypes of a witness table.
-  void collect(SILWitnessTable *WT);
-
-  /// Clears all information about used conformances and metatypes.
-  void clear() {
-    Conformances.clear();
-    EscapingMetaTypes.clear();
-    Visited.clear();
-  }
-
-  /// For debug purposes.
-  void dump();
-
-  /// Returns the list of collected used conformances.
-  ArrayRef<const ProtocolConformance *> getUsedConformances() {
-    return Conformances;
-  }
-
-  /// Returns the list of collected escaping metatypes.
-  ArrayRef<const NominalTypeDecl *> getEscapingMetaTypes() {
-    return EscapingMetaTypes;
-  }
-
-  /// Returns true if \p Conf is in the list of used conformances.
-  bool isUsed(const ProtocolConformance *Conf) {
-    return Visited.count(Conf) != 0;
-  }
-
-  /// Returns true if the metatype of \p NT is in the list of escaping
-  /// metatypes.
-  bool isMetaTypeEscaping(const NominalTypeDecl *NT) {
-    return Visited.count(NT) != 0;
-  }
-};
-
 /// A utility class for evaluating whether a newly parsed or deserialized
 /// function has qualified or unqualified ownership.
 ///

lib/IRGen/GenDecl.cpp

@@ -849,19 +849,9 @@ void IRGenerator::emitGlobalTopLevel() {
   // Emit witness tables.
   for (SILWitnessTable &wt : PrimaryIGM->getSILModule().getWitnessTableList()) {
     CurrentIGMPtr IGM = getGenModule(wt.getConformance()->getDeclContext());
-#ifndef NDEBUG
-    IGM->EligibleConfs.collect(&wt);
-    IGM->CurrentWitnessTable = &wt;
-#endif
-
     if (!canEmitWitnessTableLazily(&wt)) {
       IGM->emitSILWitnessTable(&wt);
     }
-
-#ifndef NDEBUG
-    IGM->EligibleConfs.clear();
-    IGM->CurrentWitnessTable = nullptr;
-#endif
   }
 
   for (auto Iter : *this) {
@@ -1895,83 +1885,6 @@ IRGenModule::getAddrOfLLVMVariable(LinkEntity entity, Alignment alignment,
   llvm_unreachable("bad reference kind");
 }
 
-void IRGenModule::checkEligibleConf(const ProtocolConformance *Conf) {
-#ifndef NDEBUG
-  if (!ConformanceCollector::verifyInIRGen())
-    return;
-
-  if (EligibleConfs.isUsed(Conf))
-    return;
-
-  if (CurrentInst) {
-    llvm::errs() << "## Conformance: ";
-    Conf->dump();
-    llvm::errs() << "## Inst: ";
-    CurrentInst->dump();
-    llvm_unreachable(
-                "ConformanceCollector is missing a conformance in instruction");
-  }
-  if (CurrentWitnessTable) {
-    llvm_unreachable(
-              "ConformanceCollector is missing a conformance in witness table");
-  }
-#endif
-}
-
-void IRGenModule::checkEligibleMetaType(NominalTypeDecl *NT) {
-#ifndef NDEBUG
-  if (!ConformanceCollector::verifyInIRGen())
-    return;
-
-  if (!NT || EligibleConfs.isMetaTypeEscaping(NT))
-    return;
-
-  if (CurrentInst) {
-    // Ignore instructions which may use a metatype but do not let escape it.
-    switch (CurrentInst->getKind()) {
-      case ValueKind::DestroyAddrInst:
-      case ValueKind::StructElementAddrInst:
-      case ValueKind::TupleElementAddrInst:
-      case ValueKind::InjectEnumAddrInst:
-      case ValueKind::SwitchEnumAddrInst:
-      case ValueKind::SelectEnumAddrInst:
-      case ValueKind::IndexAddrInst:
-      case ValueKind::RefElementAddrInst:
-      case ValueKind::RefTailAddrInst:
-      case ValueKind::TailAddrInst:
-      case ValueKind::AllocValueBufferInst:
-      case ValueKind::ProjectValueBufferInst:
-      case ValueKind::ProjectBoxInst:
-      case ValueKind::CopyAddrInst:
-      case ValueKind::UncheckedRefCastAddrInst:
-      case ValueKind::AllocStackInst:
-      case ValueKind::SuperMethodInst:
-      case ValueKind::WitnessMethodInst:
-      case ValueKind::DeallocRefInst:
-      case ValueKind::AllocGlobalInst:
-        return;
-      case ValueKind::ApplyInst:
-      case ValueKind::TryApplyInst:
-      case ValueKind::PartialApplyInst:
-        // It's not trivial to find the non-escaping vs. escaping meta-
-        // types of an apply. Therefore we just trust the ConformanceCollector
-        // that it does the right job.
-        return;
-      default:
-        break;
-    }
-    llvm::errs() << "## NominalType: " << NT->getName() << "\n## Inst: ";
-    CurrentInst->dump();
-    llvm_unreachable(
-                  "ConformanceCollector is missing a metatype in instruction");
-  }
-  if (CurrentWitnessTable) {
-    llvm_unreachable(
-                "ConformanceCollector is missing a metatype in witness table");
-  }
-#endif
-}
-
 /// A convenient wrapper around getAddrOfLLVMVariable which uses the
 /// default type as the definition type.
 llvm::Constant *
@@ -2513,7 +2426,6 @@ IRGenModule::getAddrOfTypeMetadataAccessFunction(CanType type,
                                               ForDefinition_t forDefinition) {
   assert(!type->hasArchetype() && !type->hasTypeParameter());
   NominalTypeDecl *Nominal = type->getNominalOrBoundGenericNominal();
-  checkEligibleMetaType(Nominal);
   IRGen.addLazyTypeMetadata(Nominal);
 
   LinkEntity entity = LinkEntity::forTypeMetadataAccessFunction(type);
@@ -2537,7 +2449,6 @@ IRGenModule::getAddrOfGenericTypeMetadataAccessFunction(
                                            ForDefinition_t forDefinition) {
   assert(!genericArgs.empty());
   assert(nominal->isGenericContext());
-  checkEligibleMetaType(nominal);
   IRGen.addLazyTypeMetadata(nominal);
 
   auto type = nominal->getDeclaredType()->getCanonicalType();
@@ -2561,7 +2472,6 @@ llvm::Constant *
 IRGenModule::getAddrOfTypeMetadataLazyCacheVariable(CanType type,
                                               ForDefinition_t forDefinition) {
   assert(!type->hasArchetype() && !type->hasTypeParameter());
-  checkEligibleMetaType(type->getNominalOrBoundGenericNominal());
   LinkEntity entity = LinkEntity::forTypeMetadataLazyCacheVariable(type);
   return getAddrOfLLVMVariable(entity, getPointerAlignment(), forDefinition,
                                TypeMetadataPtrTy, DebugTypeInfo());
@@ -2712,7 +2622,6 @@ ConstantReference IRGenModule::getAddrOfTypeMetadata(CanType concreteType,
                                                SymbolReferenceKind refKind) {
   assert(isPattern || !isa<UnboundGenericType>(concreteType));
 
-  checkEligibleMetaType(concreteType->getNominalOrBoundGenericNominal());
   llvm::Type *defaultVarTy;
   unsigned adjustmentIndex;
   Alignment alignment = getPointerAlignment();
@@ -2807,7 +2716,6 @@ ConstantReference IRGenModule::getAddrOfTypeMetadata(CanType concreteType,
 llvm::Constant *IRGenModule::getAddrOfNominalTypeDescriptor(NominalTypeDecl *D,
                                                 ConstantInitFuture definition) {
   assert(definition && "not defining nominal type descriptor?");
-  checkEligibleMetaType(D);
   auto entity = LinkEntity::forNominalTypeDescriptor(D);
   return getAddrOfLLVMVariable(entity, getPointerAlignment(),
                                definition,
@@ -3181,7 +3089,6 @@ IRGenModule::getResilienceExpansionForLayout(SILGlobalVariable *global) {
 llvm::Constant *IRGenModule::
 getAddrOfGenericWitnessTableCache(const NormalProtocolConformance *conf,
                                   ForDefinition_t forDefinition) {
-  checkEligibleConf(conf);
   auto entity = LinkEntity::forGenericProtocolWitnessTableCache(conf);
   auto expectedTy = getGenericWitnessTableCacheTy();
   return getAddrOfLLVMVariable(entity, getPointerAlignment(), forDefinition,
@@ -3191,7 +3098,6 @@ getAddrOfGenericWitnessTableCache(const NormalProtocolConformance *conf,
 llvm::Function *
 IRGenModule::getAddrOfGenericWitnessTableInstantiationFunction(
                                       const NormalProtocolConformance *conf) {
-  checkEligibleConf(conf);
   auto forDefinition = ForDefinition;
 
   LinkEntity entity =
@@ -3238,8 +3144,6 @@ llvm::Function *
 IRGenModule::getAddrOfWitnessTableAccessFunction(
                                       const NormalProtocolConformance *conf,
                                               ForDefinition_t forDefinition) {
-  checkEligibleConf(conf);
-
   IRGen.addLazyWitnessTable(conf);
 
   LinkEntity entity = LinkEntity::forProtocolWitnessTableAccessFunction(conf);
@@ -3268,7 +3172,6 @@ IRGenModule::getAddrOfWitnessTableLazyAccessFunction(
                                       const NormalProtocolConformance *conf,
                                               CanType conformingType,
                                               ForDefinition_t forDefinition) {
-  checkEligibleConf(conf);
   LinkEntity entity =
     LinkEntity::forProtocolWitnessTableLazyAccessFunction(conf, conformingType);
   llvm::Function *&entry = GlobalFuncs[entity];
@@ -3293,7 +3196,6 @@ IRGenModule::getAddrOfWitnessTableLazyCacheVariable(
                                               CanType conformingType,
                                               ForDefinition_t forDefinition) {
   assert(!conformingType->hasArchetype());
-  checkEligibleConf(conf);
   LinkEntity entity =
     LinkEntity::forProtocolWitnessTableLazyCacheVariable(conf, conformingType);
   return getAddrOfLLVMVariable(entity, getPointerAlignment(),
@@ -3310,7 +3212,6 @@ IRGenModule::getAddrOfWitnessTableLazyCacheVariable(
 llvm::Constant*
 IRGenModule::getAddrOfWitnessTable(const NormalProtocolConformance *conf,
                                    ConstantInit definition) {
-  checkEligibleConf(conf);
   IRGen.addLazyWitnessTable(conf);
 
   auto entity = LinkEntity::forDirectProtocolWitnessTable(conf);
@@ -3322,7 +3223,6 @@ llvm::Function *
 IRGenModule::getAddrOfAssociatedTypeMetadataAccessFunction(
                                   const NormalProtocolConformance *conformance,
                                   AssociatedTypeDecl *associate) {
-  checkEligibleConf(conformance);
   auto forDefinition = ForDefinition;
 
   LinkEntity entity =
@@ -3344,7 +3244,6 @@ IRGenModule::getAddrOfAssociatedTypeWitnessTableAccessFunction(
                                   const NormalProtocolConformance *conformance,
                                   CanType associatedType,
                                   ProtocolDecl *associatedProtocol) {
-  checkEligibleConf(conformance);
   auto forDefinition = ForDefinition;
 
   LinkEntity entity =

lib/IRGen/IRGenModule.cpp

@@ -135,9 +135,6 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
       DataLayout(target->createDataLayout()), Triple(Context.LangOpts.Target),
       TargetMachine(std::move(target)), silConv(irgen.SIL),
       OutputFilename(OutputFilename),
-#ifndef NDEBUG
-      EligibleConfs(getSILModule()),
-#endif
       TargetInfo(SwiftTargetInfo::get(*this)), DebugInfo(nullptr),
       ModuleHash(nullptr), ObjCInterop(Context.LangOpts.EnableObjCInterop),
       Types(*new TypeConverter(*this)) {

lib/IRGen/IRGenModule.h

@@ -21,8 +21,6 @@
 #include "swift/AST/Decl.h"
 #include "swift/AST/Module.h"
 #include "swift/SIL/SILFunction.h"
-#include "swift/SIL/SILWitnessTable.h"
-#include "swift/SIL/InstructionUtils.h"
 #include "swift/Basic/LLVM.h"
 #include "swift/Basic/ClusteredBitVector.h"
 #include "swift/Basic/SuccessorMap.h"
@@ -396,14 +394,7 @@ class IRGenModule {
   SILModuleConventions silConv;
 
   llvm::SmallString<128> OutputFilename;
-
-#ifndef NDEBUG
-  // Used for testing ConformanceCollector.
-  ConformanceCollector EligibleConfs;
-  SILInstruction *CurrentInst = nullptr;
-  SILWitnessTable *CurrentWitnessTable = nullptr;
-#endif
-
+  
   /// Order dependency -- TargetInfo must be initialized after Opts.
   const SwiftTargetInfo TargetInfo;
   /// Holds lexical scope info, etc. Is a nullptr if we compile without -g.
@@ -1049,9 +1040,6 @@ private:                            \
                                         DebugTypeInfo debugType,
                                         SymbolReferenceKind refKind);
 
-  void checkEligibleConf(const ProtocolConformance *Conf);
-  void checkEligibleMetaType(NominalTypeDecl *NT);
-
   void emitLazyPrivateDefinitions();
   void addRuntimeResolvableType(CanType type);
 

lib/IRGen/IRGenSIL.cpp

@@ -44,6 +44,7 @@
 #include "swift/SIL/SILModule.h"
 #include "swift/SIL/SILType.h"
 #include "swift/SIL/SILVisitor.h"
+#include "swift/SIL/InstructionUtils.h"
 #include "clang/CodeGen/CodeGenABITypes.h"
 
 #include "CallEmission.h"
@@ -1589,10 +1590,6 @@ void IRGenSILFunction::visitSILBasicBlock(SILBasicBlock *BB) {
 
   for (auto InsnIter = BB->begin(); InsnIter != BB->end(); ++InsnIter) {
     auto &I = *InsnIter;
-#ifndef NDEBUG
-    IGM.EligibleConfs.collect(&I);
-    IGM.CurrentInst = &I;
-#endif
     if (IGM.DebugInfo) {
       // Set the debug info location for I, if applicable.
       SILLocation ILoc = I.getLoc();
@@ -1647,10 +1644,6 @@ void IRGenSILFunction::visitSILBasicBlock(SILBasicBlock *BB) {
     }
     visit(&I);
 
-#ifndef NDEBUG
-    IGM.EligibleConfs.clear();
-    IGM.CurrentInst = nullptr;
-#endif
   }
 
   assert(Builder.hasPostTerminatorIP() && "SIL bb did not terminate block?!");