pkg/wasm_builder/lib/src/builder/functions.dart

// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import '../ir/ir.dart' as ir;
import 'builder.dart';
import 'util.dart';

/// The interface for the functions in a module.
class FunctionsBuilder with Builder<ir.Functions> {
  final ModuleBuilder _moduleBuilder;
  final _functionBuilders = <FunctionBuilder>[];
  final _importedFunctions = <ir.ImportedFunction>[];

  FunctionsBuilder(this._moduleBuilder);

  void collectUsedTypes(Set<ir.DefType> usedTypes) {
    for (final f in _functionBuilders) {
      usedTypes.add(f.type);
      f.body.collectUsedTypes(usedTypes);
    }
    for (final f in _importedFunctions) {
      usedTypes.add(f.type);
    }
  }

  /// Defines a new function in this module with the given function type.
  ///
  /// The [ir.DefinedFunction.body] must be completed (including the terminating
  /// `end`) before the module can be serialized.
  FunctionBuilder define(ir.FunctionType type, [String? name]) {
    final function = FunctionBuilder(
      _moduleBuilder,
      ir.FinalizableIndex(),
      type,
      name,
    );
    _functionBuilders.add(function);
    return function;
  }

  /// Import a function into the module.
  ir.ImportedFunction import(
    String module,
    String name,
    ir.FunctionType type, [
    String? functionName,
  ]) {
    final function = ir.ImportedFunction(
      _moduleBuilder.module,
      module,
      name,
      ir.FinalizableIndex(),
      type,
      functionName,
    );
    _importedFunctions.add(function);
    return function;
  }

  @override
  ir.Functions forceBuild() {
    final built = finalizeImportsAndBuilders<ir.DefinedFunction>(
      _importedFunctions,
      _functionBuilders,
    );
    return ir.Functions(_importedFunctions, built);
  }
}