src/runtime_debug.js

/**
 * @license
 * Copyright 2020 The Emscripten Authors
 * SPDX-License-Identifier: MIT
 */

#if ASSERTIONS

function legacyModuleProp(prop, newName) {
  if (!Object.getOwnPropertyDescriptor(Module, prop)) {
    Object.defineProperty(Module, prop, {
      configurable: true,
      get: function() {
        abort('Module.' + prop + ' has been replaced with plain ' + newName + ' (the initial value can be provided on Module, but after startup the value is only looked for on a local variable of that name)');
      }
    });
  }
}

function ignoredModuleProp(prop) {
  if (Object.getOwnPropertyDescriptor(Module, prop)) {
    abort('`Module.' + prop + '` was supplied but `' + prop + '` not included in INCOMING_MODULE_JS_API');
  }
}

// forcing the filesystem exports a few things by default
function isExportedByForceFilesystem(name) {
  return name === 'FS_createPath' ||
         name === 'FS_createDataFile' ||
         name === 'FS_createPreloadedFile' ||
         name === 'FS_unlink' ||
         name === 'addRunDependency' ||
#if !WASMFS
         // The old FS has some functionality that WasmFS lacks.
         name === 'FS_createLazyFile' ||
         name === 'FS_createDevice' ||
#endif
         name === 'removeRunDependency';
}

function missingGlobal(sym, msg) {
  if (typeof globalThis !== 'undefined') {
    Object.defineProperty(globalThis, sym, {
      configurable: true,
      get: function() {
        warnOnce('`' + sym + '` is not longer defined by emscripten. ' + msg);
        return undefined;
      }
    });
  }
}

missingGlobal('buffer', 'Please use HEAP8.buffer or wasmMemory.buffer');

function missingLibrarySymbol(sym) {
  if (typeof globalThis !== 'undefined' && !Object.getOwnPropertyDescriptor(globalThis, sym)) {
    Object.defineProperty(globalThis, sym, {
      configurable: true,
      get: function() {
        // Can't `abort()` here because it would break code that does runtime
        // checks.  e.g. `if (typeof SDL === 'undefined')`.
        var msg = '`' + sym + '` is a library symbol and not included by default; add it to your library.js __deps or to DEFAULT_LIBRARY_FUNCS_TO_INCLUDE on the command line';
        // DEFAULT_LIBRARY_FUNCS_TO_INCLUDE requires the name as it appears in
        // library.js, which means $name for a JS name with no prefix, or name
        // for a JS name like _name.
        var librarySymbol = sym;
        if (!librarySymbol.startsWith('_')) {
          librarySymbol = '$' + sym;
        }
        msg += " (e.g. -sDEFAULT_LIBRARY_FUNCS_TO_INCLUDE=" + librarySymbol + ")";
        if (isExportedByForceFilesystem(sym)) {
          msg += '. Alternatively, forcing filesystem support (-sFORCE_FILESYSTEM) can export this for you';
        }
        warnOnce(msg);
        return undefined;
      }
    });
  }
  // Any symbol that is not included from the JS libary is also (by definition)
  // not exported on the Module object.
  unexportedRuntimeSymbol(sym);
}

function unexportedRuntimeSymbol(sym) {
  if (!Object.getOwnPropertyDescriptor(Module, sym)) {
    Object.defineProperty(Module, sym, {
      configurable: true,
      get: function() {
        var msg = "'" + sym + "' was not exported. add it to EXPORTED_RUNTIME_METHODS (see the FAQ)";
        if (isExportedByForceFilesystem(sym)) {
          msg += '. Alternatively, forcing filesystem support (-sFORCE_FILESYSTEM) can export this for you';
        }
        abort(msg);
      }
    });
  }
}
#endif

#if RUNTIME_DEBUG
var runtimeDebug = true; // Switch to false at runtime to disable logging at the right times

var printObjectList = [];

function prettyPrint(arg) {
  if (typeof arg == 'undefined') return '!UNDEFINED!';
  if (typeof arg == 'boolean') arg = arg + 0;
  if (!arg) return arg;
  var index = printObjectList.indexOf(arg);
  if (index >= 0) return '<' + arg + '|' + index + '>';
  if (arg.toString() == '[object HTMLImageElement]') {
    return arg + '\n\n';
  }
  if (arg.byteLength) {
    return '{' + Array.prototype.slice.call(arg, 0, Math.min(arg.length, 400)) + '}';
  }
  if (typeof arg == 'function') {
    return '<function>';
  } else if (typeof arg == 'object') {
    printObjectList.push(arg);
    return '<' + arg + '|' + (printObjectList.length-1) + '>';
  } else if (typeof arg == 'number') {
    if (arg > 0) return ptrToString(arg) + ' (' + arg + ')';
  }
  return arg;
}
#endif

#if ASSERTIONS || RUNTIME_DEBUG
// Used by XXXXX_DEBUG settings to output debug messages.
function dbg(text) {
#if ENVIRONMENT_MAY_BE_NODE && USE_PTHREADS
  // Avoid using the console for debugging in multi-threaded node applications
  // See https://github.com/emscripten-core/emscripten/issues/14804
  if (ENVIRONMENT_IS_NODE) {
    fs.writeSync(2, text + '\n');
  } else
#endif
  // TODO(sbc): Make this configurable somehow.  Its not always convenient for
  // logging to show up as errors.
  console.error(text);
}
#endif