third_party/v8/src/torque/declaration-visitor.cc - cobalt - Git at Google

 // Copyright 2017 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #include "src/torque/declaration-visitor.h"

 #include "src/torque/ast.h"
 #include "src/torque/server-data.h"
 #include "src/torque/type-inference.h"
 #include "src/torque/type-visitor.h"

 namespace v8 {
 namespace internal {
 namespace torque {

 Namespace* GetOrCreateNamespace(const std::string& name) {
   std::vector<Namespace*> existing_namespaces = FilterDeclarables<Namespace>(
       Declarations::TryLookupShallow(QualifiedName(name)));
   if (existing_namespaces.empty()) {
     return Declarations::DeclareNamespace(name);
   }
   DCHECK_EQ(1, existing_namespaces.size());
   return existing_namespaces.front();
 }

 void PredeclarationVisitor::Predeclare(Declaration* decl) {
   CurrentSourcePosition::Scope scope(decl->pos);
   switch (decl->kind) {
 #define ENUM_ITEM(name)        \
   case AstNode::Kind::k##name: \
     return Predeclare(name::cast(decl));
     AST_TYPE_DECLARATION_NODE_KIND_LIST(ENUM_ITEM)
 #undef ENUM_ITEM
     case AstNode::Kind::kNamespaceDeclaration:
       return Predeclare(NamespaceDeclaration::cast(decl));
     case AstNode::Kind::kGenericCallableDeclaration:
       return Predeclare(GenericCallableDeclaration::cast(decl));
     case AstNode::Kind::kGenericTypeDeclaration:
       return Predeclare(GenericTypeDeclaration::cast(decl));

     default:
       // Only processes type declaration nodes, namespaces and generics.
       break;
   }
 }

 void DeclarationVisitor::Visit(Declaration* decl) {
   CurrentSourcePosition::Scope scope(decl->pos);
   switch (decl->kind) {
 #define ENUM_ITEM(name)        \
   case AstNode::Kind::k##name: \
     return Visit(name::cast(decl));
     AST_DECLARATION_NODE_KIND_LIST(ENUM_ITEM)
 #undef ENUM_ITEM
     default:
       UNIMPLEMENTED();
   }
 }

 Builtin* DeclarationVisitor::CreateBuiltin(BuiltinDeclaration* decl,
                                            std::string external_name,
                                            std::string readable_name,
                                            Signature signature,
                                            base::Optional<Statement*> body) {
   const bool javascript = decl->javascript_linkage;
   const bool varargs = decl->parameters.has_varargs;
   Builtin::Kind kind = !javascript ? Builtin::kStub
                                    : varargs ? Builtin::kVarArgsJavaScript
                                              : Builtin::kFixedArgsJavaScript;

   if (varargs && !javascript) {
     Error("Rest parameters require ", decl->name,
           " to be a JavaScript builtin");
   }

   if (javascript) {
     if (!signature.return_type->IsSubtypeOf(TypeOracle::GetJSAnyType())) {
       Error("Return type of JavaScript-linkage builtins has to be JSAny.")
           .Position(decl->return_type->pos);
     }
     for (size_t i = signature.implicit_count;
          i < signature.parameter_types.types.size(); ++i) {
       const Type* parameter_type = signature.parameter_types.types[i];
       if (!TypeOracle::GetJSAnyType()->IsSubtypeOf(parameter_type)) {
         Error(
             "Parameters of JavaScript-linkage builtins have to be a supertype "
             "of JSAny.")
             .Position(decl->parameters.types[i]->pos);
       }
     }
   }

   for (size_t i = 0; i < signature.types().size(); ++i) {
     if (signature.types()[i]->StructSupertype()) {
       Error("Builtin do not support structs as arguments, but argument ",
             signature.parameter_names[i], " has type ", *signature.types()[i],
             ".");
     }
   }

   if (signature.return_type->StructSupertype()) {
     Error("Builtins cannot return structs, but the return type is ",
           *signature.return_type, ".");
   }

   if (signature.return_type == TypeOracle::GetVoidType()) {
     Error("Builtins cannot have return type void.");
   }

   return Declarations::CreateBuiltin(std::move(external_name),
                                      std::move(readable_name), kind,
                                      std::move(signature), body);
 }

 void DeclarationVisitor::Visit(ExternalBuiltinDeclaration* decl) {
   Declarations::Declare(
       decl->name->value,
       CreateBuiltin(decl, decl->name->value, decl->name->value,
                     TypeVisitor::MakeSignature(decl), base::nullopt));
 }

 void DeclarationVisitor::Visit(ExternalRuntimeDeclaration* decl) {
   Signature signature = TypeVisitor::MakeSignature(decl);
   if (signature.parameter_types.types.size() == 0) {
     ReportError(
         "Missing parameters for runtime function, at least the context "
         "parameter is required.");
   }
   if (!(signature.parameter_types.types[0] == TypeOracle::GetContextType() ||
         signature.parameter_types.types[0] == TypeOracle::GetNoContextType())) {
     ReportError(
         "first parameter to runtime functions has to be the context and have "
         "type Context or NoContext, but found type ",
         *signature.parameter_types.types[0]);
   }
   if (!(signature.return_type->IsSubtypeOf(TypeOracle::GetStrongTaggedType()) ||
         signature.return_type == TypeOracle::GetVoidType() ||
         signature.return_type == TypeOracle::GetNeverType())) {
     ReportError(
         "runtime functions can only return strong tagged values, but "
         "found type ",
         signature.return_type);
   }
   for (const Type* parameter_type : signature.parameter_types.types) {
     if (!parameter_type->IsSubtypeOf(TypeOracle::GetStrongTaggedType())) {
       ReportError(
           "runtime functions can only take strong tagged parameters, but "
           "found type ",
           *parameter_type);
     }
   }

   Declarations::DeclareRuntimeFunction(decl->name->value, signature);
 }

 void DeclarationVisitor::Visit(ExternalMacroDeclaration* decl) {
   Declarations::DeclareMacro(
       decl->name->value, true, decl->external_assembler_name,
       TypeVisitor::MakeSignature(decl), base::nullopt, decl->op);
 }

 void DeclarationVisitor::Visit(TorqueBuiltinDeclaration* decl) {
   Declarations::Declare(
       decl->name->value,
       CreateBuiltin(decl, decl->name->value, decl->name->value,
                     TypeVisitor::MakeSignature(decl), decl->body));
 }

 void DeclarationVisitor::Visit(TorqueMacroDeclaration* decl) {
   Macro* macro = Declarations::DeclareMacro(
       decl->name->value, decl->export_to_csa, base::nullopt,
       TypeVisitor::MakeSignature(decl), decl->body, decl->op);
   // TODO(szuend): Set identifier_position to decl->name->pos once all callable
   // names are changed from std::string to Identifier*.
   macro->SetPosition(decl->pos);
 }

 void DeclarationVisitor::Visit(IntrinsicDeclaration* decl) {
   Declarations::DeclareIntrinsic(decl->name->value,
                                  TypeVisitor::MakeSignature(decl));
 }

 void DeclarationVisitor::Visit(ConstDeclaration* decl) {
   Declarations::DeclareNamespaceConstant(
       decl->name, TypeVisitor::ComputeType(decl->type), decl->expression);
 }

 void DeclarationVisitor::Visit(SpecializationDeclaration* decl) {
   std::vector<GenericCallable*> generic_list =
       Declarations::LookupGeneric(decl->name->value);
   // Find the matching generic specialization based on the concrete parameter
   // list.
   GenericCallable* matching_generic = nullptr;
   Signature signature_with_types = TypeVisitor::MakeSignature(decl);
   for (GenericCallable* generic : generic_list) {
     // This argument inference is just to trigger constraint checking on the
     // generic arguments.
     TypeArgumentInference inference = generic->InferSpecializationTypes(
         TypeVisitor::ComputeTypeVector(decl->generic_parameters), {});
     if (inference.HasFailed()) {
       continue;
     }
     Signature generic_signature_with_types =
         MakeSpecializedSignature(SpecializationKey<GenericCallable>{
             generic, TypeVisitor::ComputeTypeVector(decl->generic_parameters)});
     if (signature_with_types.HasSameTypesAs(generic_signature_with_types,
                                             ParameterMode::kIgnoreImplicit)) {
       if (matching_generic != nullptr) {
         std::stringstream stream;
         stream << "specialization of " << decl->name
                << " is ambigous, it matches more than one generic declaration ("
                << *matching_generic << " and " << *generic << ")";
         ReportError(stream.str());
       }
       matching_generic = generic;
     }
   }

   if (matching_generic == nullptr) {
     std::stringstream stream;
     if (generic_list.size() == 0) {
       stream << "no generic defined with the name " << decl->name;
       ReportError(stream.str());
     }
     stream << "specialization of " << decl->name
            << " doesn't match any generic declaration\n";
     stream << "specialization signature:";
     stream << "\n  " << signature_with_types;
     stream << "\ncandidates are:";
     for (GenericCallable* generic : generic_list) {
       stream << "\n  "
              << MakeSpecializedSignature(SpecializationKey<GenericCallable>{
                     generic,
                     TypeVisitor::ComputeTypeVector(decl->generic_parameters)});
     }
     ReportError(stream.str());
   }

   if (GlobalContext::collect_language_server_data()) {
     LanguageServerData::AddDefinition(decl->name->pos,
                                       matching_generic->IdentifierPosition());
   }

   CallableDeclaration* generic_declaration = matching_generic->declaration();

   Specialize(SpecializationKey<GenericCallable>{matching_generic,
                                                 TypeVisitor::ComputeTypeVector(
                                                     decl->generic_parameters)},
              generic_declaration, decl, decl->body, decl->pos);
 }

 void DeclarationVisitor::Visit(ExternConstDeclaration* decl) {
   const Type* type = TypeVisitor::ComputeType(decl->type);
   if (!type->IsConstexpr()) {
     std::stringstream stream;
     stream << "extern constants must have constexpr type, but found: \""
            << *type << "\"\n";
     ReportError(stream.str());
   }

   Declarations::DeclareExternConstant(decl->name, type, decl->literal);
 }

 void DeclarationVisitor::Visit(CppIncludeDeclaration* decl) {
   GlobalContext::AddCppInclude(decl->include_path);
 }

 void DeclarationVisitor::DeclareSpecializedTypes(
     const SpecializationKey<GenericCallable>& key) {
   size_t i = 0;
   const std::size_t generic_parameter_count =
       key.generic->generic_parameters().size();
   if (generic_parameter_count != key.specialized_types.size()) {
     std::stringstream stream;
     stream << "Wrong generic argument count for specialization of \""
            << key.generic->name() << "\", expected: " << generic_parameter_count
            << ", actual: " << key.specialized_types.size();
     ReportError(stream.str());
   }

   for (auto type : key.specialized_types) {
     Identifier* generic_type_name = key.generic->generic_parameters()[i++].name;
     TypeAlias* alias = Declarations::DeclareType(generic_type_name, type);
     alias->SetIsUserDefined(false);
   }
 }

 Signature DeclarationVisitor::MakeSpecializedSignature(
     const SpecializationKey<GenericCallable>& key) {
   CurrentScope::Scope generic_scope(key.generic->ParentScope());
   // Create a temporary fake-namespace just to temporarily declare the
   // specialization aliases for the generic types to create a signature.
   Namespace tmp_namespace("_tmp");
   CurrentScope::Scope tmp_namespace_scope(&tmp_namespace);
   DeclareSpecializedTypes(key);
   return TypeVisitor::MakeSignature(key.generic->declaration());
 }

 Callable* DeclarationVisitor::SpecializeImplicit(
     const SpecializationKey<GenericCallable>& key) {
   base::Optional<Statement*> body = key.generic->CallableBody();
   if (!body && IntrinsicDeclaration::DynamicCast(key.generic->declaration()) ==
                    nullptr) {
     ReportError("missing specialization of ", key.generic->name(),
                 " with types <", key.specialized_types, "> declared at ",
                 key.generic->Position());
   }
   SpecializationRequester requester{CurrentSourcePosition::Get(),
                                     CurrentScope::Get(), ""};
   CurrentScope::Scope generic_scope(key.generic->ParentScope());
   Callable* result = Specialize(key, key.generic->declaration(), base::nullopt,
                                 body, CurrentSourcePosition::Get());
   result->SetIsUserDefined(false);
   requester.name = result->ReadableName();
   result->SetSpecializationRequester(requester);
   CurrentScope::Scope callable_scope(result);
   DeclareSpecializedTypes(key);
   return result;
 }

 Callable* DeclarationVisitor::Specialize(
     const SpecializationKey<GenericCallable>& key,
     CallableDeclaration* declaration,
     base::Optional<const SpecializationDeclaration*> explicit_specialization,
     base::Optional<Statement*> body, SourcePosition position) {
   CurrentSourcePosition::Scope pos_scope(position);
   size_t generic_parameter_count = key.generic->generic_parameters().size();
   if (generic_parameter_count != key.specialized_types.size()) {
     std::stringstream stream;
     stream << "number of template parameters ("
            << std::to_string(key.specialized_types.size())
            << ") to intantiation of generic " << declaration->name
            << " doesnt match the generic's declaration ("
            << std::to_string(generic_parameter_count) << ")";
     ReportError(stream.str());
   }
   if (key.generic->GetSpecialization(key.specialized_types)) {
     ReportError("cannot redeclare specialization of ", key.generic->name(),
                 " with types <", key.specialized_types, ">");
   }

   Signature type_signature =
       explicit_specialization
           ? TypeVisitor::MakeSignature(*explicit_specialization)
           : MakeSpecializedSignature(key);

   std::string generated_name = Declarations::GetGeneratedCallableName(
       declaration->name->value, key.specialized_types);
   std::stringstream readable_name;
   readable_name << declaration->name->value << "<";
   bool first = true;
   for (const Type* t : key.specialized_types) {
     if (!first) readable_name << ", ";
     readable_name << *t;
     first = false;
   }
   readable_name << ">";
   Callable* callable;
   if (MacroDeclaration::DynamicCast(declaration) != nullptr) {
     callable =
         Declarations::CreateTorqueMacro(generated_name, readable_name.str(),
                                         false, type_signature, *body, true);
   } else if (IntrinsicDeclaration::DynamicCast(declaration) != nullptr) {
     callable =
         Declarations::CreateIntrinsic(declaration->name->value, type_signature);
   } else {
     BuiltinDeclaration* builtin = BuiltinDeclaration::cast(declaration);
     callable =
         CreateBuiltin(builtin, GlobalContext::MakeUniqueName(generated_name),
                       readable_name.str(), type_signature, *body);
   }
   key.generic->AddSpecialization(key.specialized_types, callable);
   return callable;
 }

 void PredeclarationVisitor::ResolvePredeclarations() {
   const auto& all_declarables = GlobalContext::AllDeclarables();
   for (size_t i = 0; i < all_declarables.size(); ++i) {
     Declarable* declarable = all_declarables[i].get();
     if (const TypeAlias* alias = TypeAlias::DynamicCast(declarable)) {
       CurrentScope::Scope scope_activator(alias->ParentScope());
       CurrentSourcePosition::Scope position_activator(alias->Position());
       alias->Resolve();
     }
   }
 }

 }  // namespace torque
 }  // namespace internal
 }  // namespace v8
	// Copyright 2017 the V8 project authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#include "src/torque/declaration-visitor.h"

	#include "src/torque/ast.h"
	#include "src/torque/server-data.h"
	#include "src/torque/type-inference.h"
	#include "src/torque/type-visitor.h"

	namespace v8 {
	namespace internal {
	namespace torque {

	Namespace* GetOrCreateNamespace(const std::string& name) {
	std::vector<Namespace*> existing_namespaces = FilterDeclarables<Namespace>(
	Declarations::TryLookupShallow(QualifiedName(name)));
	if (existing_namespaces.empty()) {
	return Declarations::DeclareNamespace(name);
	}
	DCHECK_EQ(1, existing_namespaces.size());
	return existing_namespaces.front();
	}

	void PredeclarationVisitor::Predeclare(Declaration* decl) {
	CurrentSourcePosition::Scope scope(decl->pos);
	switch (decl->kind) {
	#define ENUM_ITEM(name) \
	case AstNode::Kind::k##name: \
	return Predeclare(name::cast(decl));
	AST_TYPE_DECLARATION_NODE_KIND_LIST(ENUM_ITEM)
	#undef ENUM_ITEM
	case AstNode::Kind::kNamespaceDeclaration:
	return Predeclare(NamespaceDeclaration::cast(decl));
	case AstNode::Kind::kGenericCallableDeclaration:
	return Predeclare(GenericCallableDeclaration::cast(decl));
	case AstNode::Kind::kGenericTypeDeclaration:
	return Predeclare(GenericTypeDeclaration::cast(decl));

	default:
	// Only processes type declaration nodes, namespaces and generics.
	break;
	}
	}

	void DeclarationVisitor::Visit(Declaration* decl) {
	CurrentSourcePosition::Scope scope(decl->pos);
	switch (decl->kind) {
	#define ENUM_ITEM(name) \
	case AstNode::Kind::k##name: \
	return Visit(name::cast(decl));
	AST_DECLARATION_NODE_KIND_LIST(ENUM_ITEM)
	#undef ENUM_ITEM
	default:
	UNIMPLEMENTED();
	}
	}

	Builtin* DeclarationVisitor::CreateBuiltin(BuiltinDeclaration* decl,
	std::string external_name,
	std::string readable_name,
	Signature signature,
	base::Optional<Statement*> body) {
	const bool javascript = decl->javascript_linkage;
	const bool varargs = decl->parameters.has_varargs;
	Builtin::Kind kind = !javascript ? Builtin::kStub
	: varargs ? Builtin::kVarArgsJavaScript
	: Builtin::kFixedArgsJavaScript;

	if (varargs && !javascript) {
	Error("Rest parameters require ", decl->name,
	" to be a JavaScript builtin");
	}

	if (javascript) {
	if (!signature.return_type->IsSubtypeOf(TypeOracle::GetJSAnyType())) {
	Error("Return type of JavaScript-linkage builtins has to be JSAny.")
	.Position(decl->return_type->pos);
	}
	for (size_t i = signature.implicit_count;
	i < signature.parameter_types.types.size(); ++i) {
	const Type* parameter_type = signature.parameter_types.types[i];
	if (!TypeOracle::GetJSAnyType()->IsSubtypeOf(parameter_type)) {
	Error(
	"Parameters of JavaScript-linkage builtins have to be a supertype "
	"of JSAny.")
	.Position(decl->parameters.types[i]->pos);
	}
	}
	}

	for (size_t i = 0; i < signature.types().size(); ++i) {
	if (signature.types()[i]->StructSupertype()) {
	Error("Builtin do not support structs as arguments, but argument ",
	signature.parameter_names[i], " has type ", *signature.types()[i],
	".");
	}
	}

	if (signature.return_type->StructSupertype()) {
	Error("Builtins cannot return structs, but the return type is ",
	*signature.return_type, ".");
	}

	if (signature.return_type == TypeOracle::GetVoidType()) {
	Error("Builtins cannot have return type void.");
	}

	return Declarations::CreateBuiltin(std::move(external_name),
	std::move(readable_name), kind,
	std::move(signature), body);
	}

	void DeclarationVisitor::Visit(ExternalBuiltinDeclaration* decl) {
	Declarations::Declare(
	decl->name->value,
	CreateBuiltin(decl, decl->name->value, decl->name->value,
	TypeVisitor::MakeSignature(decl), base::nullopt));
	}

	void DeclarationVisitor::Visit(ExternalRuntimeDeclaration* decl) {
	Signature signature = TypeVisitor::MakeSignature(decl);
	if (signature.parameter_types.types.size() == 0) {
	ReportError(
	"Missing parameters for runtime function, at least the context "
	"parameter is required.");
	}
	if (!(signature.parameter_types.types[0] == TypeOracle::GetContextType() \|\|
	signature.parameter_types.types[0] == TypeOracle::GetNoContextType())) {
	ReportError(
	"first parameter to runtime functions has to be the context and have "
	"type Context or NoContext, but found type ",
	*signature.parameter_types.types[0]);
	}
	if (!(signature.return_type->IsSubtypeOf(TypeOracle::GetStrongTaggedType()) \|\|
	signature.return_type == TypeOracle::GetVoidType() \|\|
	signature.return_type == TypeOracle::GetNeverType())) {
	ReportError(
	"runtime functions can only return strong tagged values, but "
	"found type ",
	signature.return_type);
	}
	for (const Type* parameter_type : signature.parameter_types.types) {
	if (!parameter_type->IsSubtypeOf(TypeOracle::GetStrongTaggedType())) {
	ReportError(
	"runtime functions can only take strong tagged parameters, but "
	"found type ",
	*parameter_type);
	}
	}

	Declarations::DeclareRuntimeFunction(decl->name->value, signature);
	}

	void DeclarationVisitor::Visit(ExternalMacroDeclaration* decl) {
	Declarations::DeclareMacro(
	decl->name->value, true, decl->external_assembler_name,
	TypeVisitor::MakeSignature(decl), base::nullopt, decl->op);
	}

	void DeclarationVisitor::Visit(TorqueBuiltinDeclaration* decl) {
	Declarations::Declare(
	decl->name->value,
	CreateBuiltin(decl, decl->name->value, decl->name->value,
	TypeVisitor::MakeSignature(decl), decl->body));
	}

	void DeclarationVisitor::Visit(TorqueMacroDeclaration* decl) {
	Macro* macro = Declarations::DeclareMacro(
	decl->name->value, decl->export_to_csa, base::nullopt,
	TypeVisitor::MakeSignature(decl), decl->body, decl->op);
	// TODO(szuend): Set identifier_position to decl->name->pos once all callable
	// names are changed from std::string to Identifier*.
	macro->SetPosition(decl->pos);
	}

	void DeclarationVisitor::Visit(IntrinsicDeclaration* decl) {
	Declarations::DeclareIntrinsic(decl->name->value,
	TypeVisitor::MakeSignature(decl));
	}

	void DeclarationVisitor::Visit(ConstDeclaration* decl) {
	Declarations::DeclareNamespaceConstant(
	decl->name, TypeVisitor::ComputeType(decl->type), decl->expression);
	}

	void DeclarationVisitor::Visit(SpecializationDeclaration* decl) {
	std::vector<GenericCallable*> generic_list =
	Declarations::LookupGeneric(decl->name->value);
	// Find the matching generic specialization based on the concrete parameter
	// list.
	GenericCallable* matching_generic = nullptr;
	Signature signature_with_types = TypeVisitor::MakeSignature(decl);
	for (GenericCallable* generic : generic_list) {
	// This argument inference is just to trigger constraint checking on the
	// generic arguments.
	TypeArgumentInference inference = generic->InferSpecializationTypes(
	TypeVisitor::ComputeTypeVector(decl->generic_parameters), {});
	if (inference.HasFailed()) {
	continue;
	}
	Signature generic_signature_with_types =
	MakeSpecializedSignature(SpecializationKey<GenericCallable>{
	generic, TypeVisitor::ComputeTypeVector(decl->generic_parameters)});
	if (signature_with_types.HasSameTypesAs(generic_signature_with_types,
	ParameterMode::kIgnoreImplicit)) {
	if (matching_generic != nullptr) {
	std::stringstream stream;
	stream << "specialization of " << decl->name
	<< " is ambigous, it matches more than one generic declaration ("
	<< matching_generic << " and " << generic << ")";
	ReportError(stream.str());
	}
	matching_generic = generic;
	}
	}

	if (matching_generic == nullptr) {
	std::stringstream stream;
	if (generic_list.size() == 0) {
	stream << "no generic defined with the name " << decl->name;
	ReportError(stream.str());
	}
	stream << "specialization of " << decl->name
	<< " doesn't match any generic declaration\n";
	stream << "specialization signature:";
	stream << "\n " << signature_with_types;
	stream << "\ncandidates are:";
	for (GenericCallable* generic : generic_list) {
	stream << "\n "
	<< MakeSpecializedSignature(SpecializationKey<GenericCallable>{
	generic,
	TypeVisitor::ComputeTypeVector(decl->generic_parameters)});
	}
	ReportError(stream.str());
	}

	if (GlobalContext::collect_language_server_data()) {
	LanguageServerData::AddDefinition(decl->name->pos,
	matching_generic->IdentifierPosition());
	}

	CallableDeclaration* generic_declaration = matching_generic->declaration();

	Specialize(SpecializationKey<GenericCallable>{matching_generic,
	TypeVisitor::ComputeTypeVector(
	decl->generic_parameters)},
	generic_declaration, decl, decl->body, decl->pos);
	}

	void DeclarationVisitor::Visit(ExternConstDeclaration* decl) {
	const Type* type = TypeVisitor::ComputeType(decl->type);
	if (!type->IsConstexpr()) {
	std::stringstream stream;
	stream << "extern constants must have constexpr type, but found: \""
	<< *type << "\"\n";
	ReportError(stream.str());
	}

	Declarations::DeclareExternConstant(decl->name, type, decl->literal);
	}

	void DeclarationVisitor::Visit(CppIncludeDeclaration* decl) {
	GlobalContext::AddCppInclude(decl->include_path);
	}

	void DeclarationVisitor::DeclareSpecializedTypes(
	const SpecializationKey<GenericCallable>& key) {
	size_t i = 0;
	const std::size_t generic_parameter_count =
	key.generic->generic_parameters().size();
	if (generic_parameter_count != key.specialized_types.size()) {
	std::stringstream stream;
	stream << "Wrong generic argument count for specialization of \""
	<< key.generic->name() << "\", expected: " << generic_parameter_count
	<< ", actual: " << key.specialized_types.size();
	ReportError(stream.str());
	}

	for (auto type : key.specialized_types) {
	Identifier* generic_type_name = key.generic->generic_parameters()[i++].name;
	TypeAlias* alias = Declarations::DeclareType(generic_type_name, type);
	alias->SetIsUserDefined(false);
	}
	}

	Signature DeclarationVisitor::MakeSpecializedSignature(
	const SpecializationKey<GenericCallable>& key) {
	CurrentScope::Scope generic_scope(key.generic->ParentScope());
	// Create a temporary fake-namespace just to temporarily declare the
	// specialization aliases for the generic types to create a signature.
	Namespace tmp_namespace("_tmp");
	CurrentScope::Scope tmp_namespace_scope(&tmp_namespace);
	DeclareSpecializedTypes(key);
	return TypeVisitor::MakeSignature(key.generic->declaration());
	}

	Callable* DeclarationVisitor::SpecializeImplicit(
	const SpecializationKey<GenericCallable>& key) {
	base::Optional<Statement*> body = key.generic->CallableBody();
	if (!body && IntrinsicDeclaration::DynamicCast(key.generic->declaration()) ==
	nullptr) {
	ReportError("missing specialization of ", key.generic->name(),
	" with types <", key.specialized_types, "> declared at ",
	key.generic->Position());
	}
	SpecializationRequester requester{CurrentSourcePosition::Get(),
	CurrentScope::Get(), ""};
	CurrentScope::Scope generic_scope(key.generic->ParentScope());
	Callable* result = Specialize(key, key.generic->declaration(), base::nullopt,
	body, CurrentSourcePosition::Get());
	result->SetIsUserDefined(false);
	requester.name = result->ReadableName();
	result->SetSpecializationRequester(requester);
	CurrentScope::Scope callable_scope(result);
	DeclareSpecializedTypes(key);
	return result;
	}

	Callable* DeclarationVisitor::Specialize(
	const SpecializationKey<GenericCallable>& key,
	CallableDeclaration* declaration,
	base::Optional<const SpecializationDeclaration*> explicit_specialization,
	base::Optional<Statement*> body, SourcePosition position) {
	CurrentSourcePosition::Scope pos_scope(position);
	size_t generic_parameter_count = key.generic->generic_parameters().size();
	if (generic_parameter_count != key.specialized_types.size()) {
	std::stringstream stream;
	stream << "number of template parameters ("
	<< std::to_string(key.specialized_types.size())
	<< ") to intantiation of generic " << declaration->name
	<< " doesnt match the generic's declaration ("
	<< std::to_string(generic_parameter_count) << ")";
	ReportError(stream.str());
	}
	if (key.generic->GetSpecialization(key.specialized_types)) {
	ReportError("cannot redeclare specialization of ", key.generic->name(),
	" with types <", key.specialized_types, ">");
	}

	Signature type_signature =
	explicit_specialization
	? TypeVisitor::MakeSignature(*explicit_specialization)
	: MakeSpecializedSignature(key);

	std::string generated_name = Declarations::GetGeneratedCallableName(
	declaration->name->value, key.specialized_types);
	std::stringstream readable_name;
	readable_name << declaration->name->value << "<";
	bool first = true;
	for (const Type* t : key.specialized_types) {
	if (!first) readable_name << ", ";
	readable_name << *t;
	first = false;
	}
	readable_name << ">";
	Callable* callable;
	if (MacroDeclaration::DynamicCast(declaration) != nullptr) {
	callable =
	Declarations::CreateTorqueMacro(generated_name, readable_name.str(),
	false, type_signature, *body, true);
	} else if (IntrinsicDeclaration::DynamicCast(declaration) != nullptr) {
	callable =
	Declarations::CreateIntrinsic(declaration->name->value, type_signature);
	} else {
	BuiltinDeclaration* builtin = BuiltinDeclaration::cast(declaration);
	callable =
	CreateBuiltin(builtin, GlobalContext::MakeUniqueName(generated_name),
	readable_name.str(), type_signature, *body);
	}
	key.generic->AddSpecialization(key.specialized_types, callable);
	return callable;
	}

	void PredeclarationVisitor::ResolvePredeclarations() {
	const auto& all_declarables = GlobalContext::AllDeclarables();
	for (size_t i = 0; i < all_declarables.size(); ++i) {
	Declarable* declarable = all_declarables[i].get();
	if (const TypeAlias* alias = TypeAlias::DynamicCast(declarable)) {
	CurrentScope::Scope scope_activator(alias->ParentScope());
	CurrentSourcePosition::Scope position_activator(alias->Position());
	alias->Resolve();
	}
	}
	}

	} // namespace torque
	} // namespace internal
	} // namespace v8