utils/dartpad/compile_wasm.gni

# Copyright (c) 2024, 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("../../build/dart/dart_action.gni")
import("../../runtime/runtime_args.gni")
import("../../sdk_args.gni")

_dart_root = get_path_info("../..", "abspath")

# Compiles a Dart program to WebAssembly using the dart2wasm compiler.
#
# Parameters:
#   main_dart (required):
#     The path to the main Dart file.
#
#   output (optional):
#     The directory where the resulting .wasm, .mjs, .support.js, and .map
#     files should be placed.
#
#   force_product_mode (optional):
#     If true, forces the compilation to use production optimizations (-O4 and
#     minification) regardless of the build mode.
template("compile_dart2wasm") {
  assert(defined(invoker.main_dart), "Must specify 'main_dart'")
  dartaotruntime_action(target_name) {
    forward_variables_from(invoker,
                           [
                             "testonly",
                             "visibility",
                           ])

    product_mode = !dart_debug || (defined(invoker.force_product_mode) &&
                                   invoker.force_product_mode)

    main_dart = invoker.main_dart

    # The snapshot created by the dart2wasm_snapshot target
    script = "$root_out_dir/dart2wasm.snapshot"

    if (defined(invoker.package_config)) {
      package_config = invoker.package_config
    } else {
      package_config = rebase_path("$_dart_root/.dart_tool/package_config.json")
    }
    if (defined(invoker.output)) {
      output = invoker.output
    } else {
      output = "$root_out_dir/$target_name.wasm"
    }
    output_no_ext =
        get_path_info(output, "dir") + "/" + get_path_info(output, "name")
    platform_dill = "$root_out_dir/dart2wasm_platform.dill"
    depfile = "$target_gen_dir/$target_name.d"

    # The wasm-opt binary provided by //third_party/binaryen:wasm-opt target
    if (product_mode) {
      wasm_opt_binary = "$root_out_dir/wasm-opt$executable_suffix"
    }

    inputs = [
      main_dart,
      package_config,
      platform_dill,
    ]
    if (product_mode) {
      inputs += [ wasm_opt_binary ]
    }
    if (defined(invoker.inputs)) {
      inputs += invoker.inputs
    }

    # dart2wasm produces .wasm, .mjs, .support.js and .wasm.map
    outputs = [
      output,
      "${output}.map",
      "${output_no_ext}.mjs",
      "${output_no_ext}.support.js",
    ]
    if (defined(invoker.outputs)) {
      outputs += invoker.outputs
    }

    deps = [
      "../dart2wasm:dart2wasm_platform",
      "../dart2wasm:dart2wasm_snapshot",
    ]
    if (product_mode) {
      deps += [ "../../third_party/binaryen:wasm-opt" ]
    }
    if (defined(invoker.deps)) {
      deps += invoker.deps
    }

    args = [
      "--packages=" + rebase_path(package_config, root_build_dir),
      "--platform=" + rebase_path(platform_dill, root_build_dir),
      "--depfile=" + rebase_path(depfile, root_build_dir),
    ]

    if (product_mode) {
      args += [
        "--wasm-opt=" + rebase_path(wasm_opt_binary, root_build_dir),
        "--phases=cfe,tfa,codegen,opt",
        "--minify",
      ]
    }

    args += [
      "-O2",
      rebase_path(main_dart, root_build_dir),
      rebase_path(output, root_build_dir),
    ]
  }
}