IRGen support for closures that capture metadata and witness table packs

include/swift/IRGen/GenericRequirement.h

@@ -76,7 +76,6 @@ class GenericRequirement {
   }
 
   static GenericRequirement forShape(CanType type) {
-    assert(!isa<PackType>(type));
     assert(type->isParameterPack() || isa<PackArchetypeType>(type));
     return GenericRequirement(Kind::Shape, type, nullptr);
   }
@@ -92,7 +91,6 @@ class GenericRequirement {
   }
 
   static GenericRequirement forMetadata(CanType type) {
-    assert(!isa<PackType>(type));
     auto kind = ((type->isParameterPack() ||
                   isa<PackArchetypeType>(type))
                  ? Kind::MetadataPack : Kind::Metadata);
@@ -110,7 +108,6 @@ class GenericRequirement {
   }
 
   static GenericRequirement forWitnessTable(CanType type, ProtocolDecl *proto) {
-    assert(!isa<PackType>(type));
     auto kind = ((type->isParameterPack() ||
                   isa<PackArchetypeType>(type))
                  ? Kind::WitnessTablePack

include/swift/Runtime/RuntimeFunctions.def

@@ -1008,6 +1008,28 @@ FUNCTION(CompareProtocolConformanceDescriptors,
          ATTRS(NoUnwind, ReadNone, WillReturn),
          EFFECT(NoEffect)) // ?
 
+// SWIFT_RUNTIME_EXPORT SWIFT_CC(swift)
+// const Metadata * const *
+// swift_allocateMetadataPack(const Metadata * const *ptr, size_t count);
+FUNCTION(AllocateMetadataPack,
+         swift_allocateMetadataPack, SwiftCC,
+         AlwaysAvailable,  // FIXME
+         RETURNS(TypeMetadataPtrPtrTy),
+         ARGS(TypeMetadataPtrPtrTy, SizeTy),
+         ATTRS(NoUnwind, WillReturn),
+         EFFECT(MetaData)) // ?
+
+// SWIFT_RUNTIME_EXPORT SWIFT_CC(swift)
+// const WitnessTable * const *
+// swift_allocateWitnessTablePack(const WitnessTable * const *ptr, size_t count);
+FUNCTION(AllocateWitnessTablePack,
+         swift_allocateWitnessTablePack, SwiftCC,
+         AlwaysAvailable,  // FIXME
+         RETURNS(WitnessTablePtrPtrTy),
+         ARGS(WitnessTablePtrPtrTy, SizeTy),
+         ATTRS(NoUnwind, WillReturn),
+         EFFECT(MetaData)) // ?
+
 // Metadata *swift_getMetatypeMetadata(Metadata *instanceTy);
 FUNCTION(GetMetatypeMetadata, swift_getMetatypeMetadata, C_CC, AlwaysAvailable,
          RETURNS(TypeMetadataPtrTy),

lib/IRGen/GenArchetype.cpp

@@ -440,17 +440,10 @@ withOpaqueTypeGenericArgs(IRGenFunction &IGF,
     enumerateGenericSignatureRequirements(
         opaqueDecl->getGenericSignature().getCanonicalSignature(),
         [&](GenericRequirement reqt) {
-          auto ty = reqt.getTypeParameter().subst(archetype->getSubstitutions())
-                        ->getReducedType(opaqueDecl->getGenericSignature());
-          if (reqt.isAnyWitnessTable()) {
-            auto ref =
-                ProtocolConformanceRef(reqt.getProtocol())
-                    .subst(reqt.getTypeParameter(), archetype->getSubstitutions());
-            args.push_back(emitWitnessTableRef(IGF, ty, ref));
-          } else {
-            assert(reqt.isAnyMetadata());
-            args.push_back(IGF.emitAbstractTypeMetadataRef(ty));
-          }
+          auto arg = emitGenericRequirementFromSubstitutions(
+              IGF, reqt, MetadataState::Abstract,
+              archetype->getSubstitutions());
+          args.push_back(arg);
           types.push_back(args.back()->getType());
         });
     auto bufTy = llvm::StructType::get(IGF.IGM.getLLVMContext(), types);

lib/IRGen/GenFunc.cpp

@@ -1949,7 +1949,8 @@ Optional<StackAddress> irgen::emitFunctionPartialApplication(
 
   // Reserve space for polymorphic bindings.
   auto bindings = NecessaryBindings::forPartialApplyForwarder(
-      IGF.IGM, origType, subs, considerParameterSources);
+      IGF.IGM, origType, subs, outType->isNoEscape(),
+      considerParameterSources);
 
   if (!bindings.empty()) {
     hasSingleSwiftRefcountedContext = No;

lib/IRGen/GenKeyPath.cpp

@@ -89,12 +89,11 @@ bindPolymorphicArgumentsFromComponentIndices(IRGenFunction &IGF,
     args =
         IGF.Builder.CreateInBoundsGEP(IGF.IGM.Int8Ty, args, genericArgsOffset);
   }
+
   bindFromGenericRequirementsBuffer(
       IGF, requirements,
       Address(args, IGF.IGM.Int8Ty, IGF.IGM.getPointerAlignment()),
-      MetadataState::Complete, [&](CanType t) {
-        return genericEnv->mapTypeIntoContext(t)->getCanonicalType();
-      });
+      MetadataState::Complete, genericEnv->getForwardingSubstitutionMap());
 }
 
 static llvm::Function *
@@ -295,9 +294,7 @@ getLayoutFunctionForComputedComponent(IRGenModule &IGM,
       bindFromGenericRequirementsBuffer(
           IGF, requirements,
           Address(args, IGM.Int8Ty, IGF.IGM.getPointerAlignment()),
-          MetadataState::Complete, [&](CanType t) {
-            return genericEnv->mapTypeIntoContext(t)->getCanonicalType();
-          });
+          MetadataState::Complete, genericEnv->getForwardingSubstitutionMap());
     }
 
     // Run through the captured index types to determine the size and alignment
@@ -583,9 +580,7 @@ getInitializerForComputedComponent(IRGenModule &IGM,
       bindFromGenericRequirementsBuffer(
           IGF, requirements,
           Address(src, IGM.Int8Ty, IGF.IGM.getPointerAlignment()),
-          MetadataState::Complete, [&](CanType t) {
-            return genericEnv->mapTypeIntoContext(t)->getCanonicalType();
-          });
+          MetadataState::Complete, genericEnv->getForwardingSubstitutionMap());
 
     } else {
       offset = llvm::ConstantInt::get(IGM.SizeTy, 0);

lib/IRGen/GenMeta.cpp

@@ -2318,11 +2318,10 @@ namespace {
             bindFromGenericRequirementsBuffer(
                 IGF, requirements,
                 Address(bindingsBufPtr, IGM.Int8Ty, IGM.getPointerAlignment()),
-                MetadataState::Complete, [&](CanType t) {
-                  return genericEnv ? genericEnv->mapTypeIntoContext(t)
-                                          ->getCanonicalType()
-                                    : t;
-                });
+                MetadataState::Complete,
+                (genericEnv
+                 ? genericEnv->getForwardingSubstitutionMap()
+                 : SubstitutionMap()));
           }
 
           SmallVector<llvm::BasicBlock *, 4> conditionalTypes;