src/compiler.js

/**
 * @license
 * Copyright 2010 The Emscripten Authors
 * SPDX-License-Identifier: MIT
 */

// LLVM => JavaScript compiler, main entry point

var nodeFS = require('fs');
var nodePath = require('path');

// *** Environment setup code ***

// Expose functionality in the same simple way that the shells work
// Note that we pollute the global namespace here, otherwise we break in node
print = function(x) {
  process['stdout'].write(x + '\n');
};

printErr = function(x) {
  process['stderr'].write(x + '\n');
};

function find(filename) {
  var prefixes = [__dirname, process.cwd()];
  for (var i = 0; i < prefixes.length; ++i) {
    var combined = nodePath.join(prefixes[i], filename);
    if (nodeFS.existsSync(combined)) {
      return combined;
    }
  }
  return filename;
}

read = function(filename) {
  var absolute = find(filename);
  return nodeFS['readFileSync'](absolute).toString();
};

load = function(f) {
  globalEval(read(f));
};

function globalEval(x) {
  eval.call(null, x);
}

// Basic utilities

load('utility.js');

// Load settings, can be overridden by commandline

load('settings.js');
load('settings_internal.js');

var arguments_ = process['argv'].slice(2);
var settings_file = arguments_[0];

if (settings_file) {
  var settings = JSON.parse(read(settings_file));
  for (var key in settings) {
    var value = settings[key];
    if (value[0] == '@') {
      // response file type thing, workaround for large inputs: value is @path-to-file
      try {
        value = JSON.parse(read(value.substr(1)));
      } catch(e) {
        // continue normally; assume it is not a response file
      }
    }
    eval(key + ' = ' + JSON.stringify(value));
  }
}

EXPORTED_FUNCTIONS = set(EXPORTED_FUNCTIONS);
EXCEPTION_CATCHING_WHITELIST = set(EXCEPTION_CATCHING_WHITELIST);
IMPLEMENTED_FUNCTIONS = set(IMPLEMENTED_FUNCTIONS);
INCOMING_MODULE_JS_API = set(INCOMING_MODULE_JS_API);

DEAD_FUNCTIONS.forEach(function(dead) {
  DEFAULT_LIBRARY_FUNCS_TO_INCLUDE.push(dead.substr(1));
});
DEAD_FUNCTIONS = numberedSet(DEAD_FUNCTIONS);

RUNTIME_DEBUG = LIBRARY_DEBUG || GL_DEBUG;

// Output some info and warnings based on settings

if (VERBOSE) {
  printErr('VERBOSE is on, this generates a lot of output and can slow down compilation');
}

// Load compiler code

load('modules.js');
load('parseTools.js');
load('jsifier.js');
load('runtime.js');

// State computations

var ENVIRONMENTS = ENVIRONMENT.split(',');
ENVIRONMENT_MAY_BE_WEB     = !ENVIRONMENT || ENVIRONMENTS.indexOf('web') >= 0;
ENVIRONMENT_MAY_BE_WEBVIEW = !ENVIRONMENT || ENVIRONMENTS.indexOf('webview') >= 0;
ENVIRONMENT_MAY_BE_NODE    = !ENVIRONMENT || ENVIRONMENTS.indexOf('node') >= 0;
ENVIRONMENT_MAY_BE_SHELL   = !ENVIRONMENT || ENVIRONMENTS.indexOf('shell') >= 0;

// The worker case also includes Node.js workers when pthreads are
// enabled and Node.js is one of the supported environments for the build to
// run on. Node.js workers are detected as a combination of
// ENVIRONMENT_IS_WORKER and ENVIRONMENT_IS_NODE.
ENVIRONMENT_MAY_BE_WORKER = !ENVIRONMENT || ENVIRONMENTS.indexOf('worker') >= 0 ||
                            (ENVIRONMENT_MAY_BE_NODE && USE_PTHREADS);

if (ENVIRONMENT && !(ENVIRONMENT_MAY_BE_WEB || ENVIRONMENT_MAY_BE_WORKER || ENVIRONMENT_MAY_BE_NODE || ENVIRONMENT_MAY_BE_SHELL || ENVIRONMENT_MAY_BE_WEBVIEW)) {
  throw 'Invalid environment specified in "ENVIRONMENT": ' + ENVIRONMENT + '. Should be one of: web, webview, worker, node, shell.';
}

if (!ENVIRONMENT_MAY_BE_WORKER && PROXY_TO_WORKER) {
  throw 'If you specify --proxy-to-worker and specify a "-s ENVIRONMENT=" directive, it must include "worker" as a target! (Try e.g. -s ENVIRONMENT=web,worker)';
}

if (!ENVIRONMENT_MAY_BE_WORKER && USE_PTHREADS) {
  throw 'When building with multithreading enabled and a "-s ENVIRONMENT=" directive is specified, it must include "worker" as a target! (Try e.g. -s ENVIRONMENT=web,worker)';
}

//===============================
// Main
//===============================

B = new Benchmarker();
var dummyData = {functionStubs: []}

try {
  JSify(dummyData);

  B.print('glue');
} catch(err) {
  if (err.toString().indexOf('Aborting compilation due to previous errors') != -1) {
    // Compiler failed on user error, don't print the stacktrace in this case.
    printErr(err);
  } else {
    // Compiler failed on internal compiler error!
    printErr('Internal compiler error in src/compiler.js!');
    printErr('Please create a bug report at https://github.com/emscripten-core/emscripten/issues/');
    printErr('with a log of the build and the input files used to run. Exception message: "' + err + '" | ' + err.stack);
  }

  // Work around a node.js bug where stdout buffer is not flushed at process exit:
  // Instead of process.exit() directly, wait for stdout flush event.
  // See https://github.com/joyent/node/issues/1669 and https://github.com/emscripten-core/emscripten/issues/2582
  // Workaround is based on https://github.com/RReverser/acorn/commit/50ab143cecc9ed71a2d66f78b4aec3bb2e9844f6
  process['stdout']['once']('drain', function () {
    process['exit'](1);
  });
  // Make sure to print something to force the drain event to occur, in case the
  // stdout buffer was empty.
  console.log(' ');
  // Work around another node bug where sometimes 'drain' is never fired - make
  // another effort to emit the exit status, after a significant delay (if node
  // hasn't fired drain by then, give up)
  setTimeout(function() {
    process['exit'](1);
  }, 500);
}