runtime_debug.js

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

#if ASSERTIONS

// Endianness check
#if !SUPPORT_BIG_ENDIAN
(() => {
  var h16 = new Int16Array(1);
  var h8 = new Int8Array(h16.buffer);
  h16[0] = 0x6373;
  if (h8[0] !== 0x73 || h8[1] !== 0x63) throw 'Runtime error: expected the system to be little-endian! (Run with -sSUPPORT_BIG_ENDIAN to bypass)';
})();
#endif

function consumedModuleProp(prop) {
  if (!Object.getOwnPropertyDescriptor(Module, prop)) {
    Object.defineProperty(Module, prop, {
      configurable: true,
      set() {
        abort(`Attempt to set \`Module.${prop}\` after it has already been processed.  This can happen, for example, when code is injected via '--post-js' rather than '--pre-js'`);

      }
    });
  }
}

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';
}

/**
 * Intercept access to a global symbol.  This enables us to give informative
 * warnings/errors when folks attempt to use symbols they did not include in
 * their build, or no symbols that no longer exist.
 */
function hookGlobalSymbolAccess(sym, func) {
#if MODULARIZE && !EXPORT_ES6
  // In MODULARIZE mode the generated code runs inside a function scope and not
  // the global scope, and JavaScript does not provide access to function scopes
  // so we cannot dynamically modify the scrope using `defineProperty` in this
  // case.
  //
  // In this mode we simply ignore requests for `hookGlobalSymbolAccess`. Since
  // this is a debug-only feature, skipping it is not major issue.
#else
  if (typeof globalThis != 'undefined' && !Object.getOwnPropertyDescriptor(globalThis, sym)) {
    Object.defineProperty(globalThis, sym, {
      configurable: true,
      get() {
        func();
        return undefined;
      }
    });
  }
#endif
}

function missingGlobal(sym, msg) {
  hookGlobalSymbolAccess(sym, () => {
    warnOnce(`\`${sym}\` is not longer defined by emscripten. ${msg}`);
  });
}

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

function missingLibrarySymbol(sym) {
  hookGlobalSymbolAccess(sym, () => {
    // 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);
  });

  // Any symbol that is not included from the JS library is also (by definition)
  // not exported on the Module object.
  unexportedRuntimeSymbol(sym);
}

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

#if ASSERTIONS == 2

var MAX_UINT8  = (2 **  8) - 1;
var MAX_UINT16 = (2 ** 16) - 1;
var MAX_UINT32 = (2 ** 32) - 1;
var MAX_UINT53 = (2 ** 53) - 1;
var MAX_UINT64 = (2 ** 64) - 1;

var MIN_INT8  = - (2 ** ( 8 - 1));
var MIN_INT16 = - (2 ** (16 - 1));
var MIN_INT32 = - (2 ** (32 - 1));
var MIN_INT53 = - (2 ** (53 - 1));
var MIN_INT64 = - (2 ** (64 - 1));

function checkInt(value, bits, min, max) {
  assert(Number.isInteger(Number(value)), `attempt to write non-integer (${value}) into integer heap`);
  assert(value <= max, `value (${value}) too large to write as ${bits}-bit value`);
  assert(value >= min, `value (${value}) too small to write as ${bits}-bit value`);
}

var checkInt1 = (value) => checkInt(value, 1, 1);
var checkInt8 = (value) => checkInt(value, 8, MIN_INT8, MAX_UINT8);
var checkInt16 = (value) => checkInt(value, 16, MIN_INT16, MAX_UINT16);
var checkInt32 = (value) => checkInt(value, 32, MIN_INT32, MAX_UINT32);
var checkInt53 = (value) => checkInt(value, 53, MIN_INT53, MAX_UINT53);
var checkInt64 = (value) => checkInt(value, 64, MIN_INT64, MAX_UINT64);

#endif // ASSERTIONS == 2

#endif // ASSERTIONS

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

// Used by XXXXX_DEBUG settings to output debug messages.
function dbg(...args) {
  if (!runtimeDebug && typeof runtimeDebug != 'undefined') return;
#if ENVIRONMENT_MAY_BE_NODE && 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) {
    // TODO(sbc): Unify with err/out implementation in shell.sh.
    var fs = require('fs');
    var utils = require('util');
    var stringify = (a) => typeof a == 'object' ? utils.inspect(a) : a;
    fs.writeSync(1, args.map(stringify).join(' ') + '\n');
  } else
#endif
  // TODO(sbc): Make this configurable somehow.  Its not always convenient for
  // logging to show up as warnings.
  console.warn(...args);
}
#endif