Preliminary SILGen and IRGen support for nested generic types

include/swift/AST/Mangle.h

@@ -92,6 +92,7 @@ class Mangler {
   void mangleClosureEntity(const AbstractClosureExpr *closure,
                            unsigned uncurryingLevel);
   void mangleNominalType(const NominalTypeDecl *decl);
+  void mangleBoundGenericType(Type type);
   void mangleProtocolDecl(const ProtocolDecl *protocol);
   void mangleType(Type type, unsigned uncurryingLevel);
   void mangleDirectness(bool isIndirect);

lib/AST/Mangle.cpp

@@ -940,32 +940,17 @@ void Mangler::mangleType(Type type, unsigned uncurryLevel) {
     Buffer << '_';
     return;
 
-  case TypeKind::UnboundGeneric: {
-    // We normally reject unbound types in IR-generation, but there
-    // are several occasions in which we'd like to mangle them in the
-    // abstract.
-    auto decl = cast<UnboundGenericType>(tybase)->getDecl();
-    mangleNominalType(cast<NominalTypeDecl>(decl));
-    return;
-  }
-
+  case TypeKind::UnboundGeneric:
   case TypeKind::Class:
   case TypeKind::Enum:
-  case TypeKind::Struct: {
-    return mangleNominalType(cast<NominalType>(tybase)->getDecl());
-  }
-
+  case TypeKind::Struct:
   case TypeKind::BoundGenericClass:
   case TypeKind::BoundGenericEnum:
   case TypeKind::BoundGenericStruct: {
-    // type ::= 'G' <type> <type>+ '_'
-    auto *boundType = cast<BoundGenericType>(tybase);
-    Buffer << 'G';
-    mangleNominalType(boundType->getDecl());
-    for (auto arg : boundType->getGenericArgs()) {
-      mangleType(arg, /*uncurry*/ 0);
-    }
-    Buffer << '_';
+    if (type->isSpecialized())
+      mangleBoundGenericType(type);
+    else
+      mangleNominalType(tybase->getAnyNominal());
     return;
   }
 
@@ -1332,6 +1317,46 @@ void Mangler::mangleNominalType(const NominalTypeDecl *decl) {
   addSubstitution(key);
 }
 
+static void
+collectBoundGenericArgs(Type type,
+                        SmallVectorImpl<SmallVector<Type, 2>> &genericArgs) {
+  if (auto *unboundType = type->getAs<UnboundGenericType>()) {
+    if (auto parent = unboundType->getParent())
+      collectBoundGenericArgs(parent, genericArgs);
+    genericArgs.push_back({});
+  } else if (auto *nominalType = type->getAs<NominalType>()) {
+    if (auto parent = nominalType->getParent())
+      collectBoundGenericArgs(parent, genericArgs);
+    genericArgs.push_back({});
+  } else {
+    auto *boundType = type->castTo<BoundGenericType>();
+    if (auto parent = boundType->getParent())
+      collectBoundGenericArgs(parent, genericArgs);
+
+    SmallVector<Type, 2> args;
+    for (auto arg : boundType->getGenericArgs())
+      args.push_back(arg);
+    genericArgs.push_back(args);
+  }
+}
+
+void Mangler::mangleBoundGenericType(Type type) {
+  // type ::= 'G' <type> (<type>+ '_')+
+  Buffer << 'G';
+  auto *nominal = type->getAnyNominal();
+  mangleNominalType(nominal);
+
+  SmallVector<SmallVector<Type, 2>, 2> genericArgs;
+  collectBoundGenericArgs(type, genericArgs);
+  assert(!genericArgs.empty());
+
+  for (auto args : genericArgs) {
+    for (auto arg : args)
+      mangleType(arg, /*uncurry*/ 0);
+    Buffer << '_';
+  }
+}
+
 void Mangler::mangleProtocolDecl(const ProtocolDecl *protocol) {
   Buffer << 'P';
   mangleContextOf(protocol);

lib/Basic/Demangle.cpp

@@ -1154,6 +1154,73 @@ class Demangler {
     return nullptr;
   }
 
+  NodePointer demangleBoundGenericArgs(NodePointer nominalType) {
+    // Generic arguments for the outermost type come first.
+    NodePointer parentOrModule = nominalType->getChild(0);
+    if (parentOrModule->getKind() != Node::Kind::Module) {
+      parentOrModule = demangleBoundGenericArgs(parentOrModule);
+
+      // Rebuild this type with the new parent type, which may have
+      // had its generic arguments applied.
+      NodePointer result = NodeFactory::create(nominalType->getKind());
+      result->addChild(parentOrModule);
+      result->addChild(nominalType->getChild(1));
+
+      nominalType = result;
+    }
+
+    NodePointer args = NodeFactory::create(Node::Kind::TypeList);
+    while (!Mangled.nextIf('_')) {
+      NodePointer type = demangleType();
+      if (!type)
+        return nullptr;
+      args->addChild(type);
+      if (Mangled.isEmpty())
+        return nullptr;
+    }
+
+    // If there were no arguments at this level there is nothing left
+    // to do.
+    if (args->getNumChildren() == 0)
+      return nominalType;
+
+    // Otherwise, build a bound generic type node from the unbound
+    // type and arguments.
+    NodePointer unboundType = NodeFactory::create(Node::Kind::Type);
+    unboundType->addChild(nominalType);
+
+    Node::Kind kind;
+    switch (nominalType->getKind()) { // look through Type node
+      case Node::Kind::Class:
+        kind = Node::Kind::BoundGenericClass;
+        break;
+      case Node::Kind::Structure:
+        kind = Node::Kind::BoundGenericStructure;
+        break;
+      case Node::Kind::Enum:
+        kind = Node::Kind::BoundGenericEnum;
+        break;
+      default:
+        return nullptr;
+    }
+    NodePointer result = NodeFactory::create(kind);
+    result->addChild(unboundType);
+    result->addChild(args);
+    return result;
+  }
+
+  NodePointer demangleBoundGenericType() {
+    // bound-generic-type ::= 'G' nominal-type (args+ '_')+
+    //
+    // Each level of nominal type nesting has its own list of arguments.
+
+    NodePointer nominalType = demangleNominalType();
+    if (!nominalType)
+      return nullptr;
+
+    return demangleBoundGenericArgs(nominalType);
+  }
+
   NodePointer demangleContext() {
     // context ::= module
     // context ::= entity
@@ -1191,6 +1258,8 @@ class Demangler {
       return demangleSubstitutionIndex();
     if (Mangled.nextIf('s'))
       return NodeFactory::create(Node::Kind::Module, STDLIB_NAME);
+    if (Mangled.nextIf('G'))
+      return demangleBoundGenericType();
     if (isStartOfEntity(Mangled.peek()))
       return demangleEntity();
     return demangleModule();
@@ -1872,37 +1941,7 @@ class Demangler {
       return demangleFunctionType(Node::Kind::UncurriedFunctionType);
     }
     if (c == 'G') {
-      NodePointer unboundType = demangleType();
-      if (!unboundType)
-        return nullptr;
-      NodePointer type_list = NodeFactory::create(Node::Kind::TypeList);
-      while (!Mangled.nextIf('_')) {
-        NodePointer type = demangleType();
-        if (!type)
-          return nullptr;
-        type_list->addChild(type);
-        if (Mangled.isEmpty())
-          return nullptr;
-      }
-      Node::Kind bound_type_kind;
-      switch (unboundType->getChild(0)->getKind()) { // look through Type node
-        case Node::Kind::Class:
-          bound_type_kind = Node::Kind::BoundGenericClass;
-          break;
-        case Node::Kind::Structure:
-          bound_type_kind = Node::Kind::BoundGenericStructure;
-          break;
-        case Node::Kind::Enum:
-          bound_type_kind = Node::Kind::BoundGenericEnum;
-          break;
-        default:
-          return nullptr;
-      }
-      NodePointer type_application =
-          NodeFactory::create(bound_type_kind);
-      type_application->addChild(unboundType);
-      type_application->addChild(type_list);
-      return type_application;
+      return demangleBoundGenericType();
     }
     if (c == 'X') {
       if (Mangled.nextIf('b')) {
@@ -2049,10 +2088,8 @@ class Demangler {
 
       return nullptr;
     }
-    if (isStartOfNominalType(c)) {
-      NodePointer nominal_type = demangleDeclarationName(nominalTypeMarkerToNodeKind(c));
-      return nominal_type;
-    }
+    if (isStartOfNominalType(c))
+      return demangleDeclarationName(nominalTypeMarkerToNodeKind(c));
     return nullptr;
   }