prepack/lib/partial-evaluators/BinaryExpression.js

Execute a JS bundle, serialize global state and side effects to a snapshot that can be quickly restored.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});

exports.default = function (ast, strictCode, env, realm) {
  let [lval, leftAst, leftIO] = env.partiallyEvaluateCompletionDeref(ast.left, strictCode);
  if (lval instanceof _completions.AbruptCompletion) return [lval, leftAst, leftIO];
  let leftCompletion;
  [leftCompletion, lval] = _singletons.Join.unbundleNormalCompletion(lval);
  (0, _invariant2.default)(lval instanceof _index.Value);

  let [rval, rightAst, rightIO] = env.partiallyEvaluateCompletionDeref(ast.right, strictCode);
  let io = leftIO.concat(rightIO);
  if (rval instanceof _completions.AbruptCompletion) {
    // todo: if leftCompletion is a PossiblyNormalCompletion, compose
    return [rval, t.binaryExpression(ast.operator, leftAst, rightAst), io];
  }
  let rightCompletion;
  [rightCompletion, rval] = _singletons.Join.unbundleNormalCompletion(rval);
  (0, _invariant2.default)(rval instanceof _index.Value);

  let op = ast.operator;
  let resultValue, resultAst;
  if (lval instanceof _index.ConcreteValue) {
    if (rval instanceof _index.ConcreteValue) {
      resultValue = (0, _BinaryExpression.computeBinary)(realm, op, lval, rval);
      resultAst = t.valueToNode(resultValue.serialize());
    }
  }
  // if resultValue is undefined, one or both operands are abstract.
  if (resultValue === undefined && (op === "==" || op === "===" || op === "!=" || op === "!==")) {
    // When comparing to null or undefined, we can return a compile time value if we know the
    // other operand must be an object.
    if (!lval.mightNotBeObject() && (rval instanceof _index.NullValue || rval instanceof _index.UndefinedValue) || !rval.mightNotBeObject() && (lval instanceof _index.NullValue || lval instanceof _index.UndefinedValue)) {
      resultValue = new _index.BooleanValue(realm, op[0] !== "=");
      resultAst = t.valueToNode(resultValue.serialize());
    }
  }
  // todo: special case if one result is known to be 0 or 1
  if (resultAst === undefined) {
    resultAst = t.binaryExpression(op, leftAst, rightAst);
  }
  return createAbstractValueForBinary(op, resultAst, lval, rval, leftAst.loc, rightAst.loc, leftCompletion, rightCompletion, resultValue, io, realm);
};

exports.createAbstractValueForBinary = createAbstractValueForBinary;

var _BinaryExpression = require("../evaluators/BinaryExpression.js");

var _completions = require("../completions.js");

var _errors = require("../errors.js");

var _singletons = require("../singletons.js");

var _index = require("../values/index.js");

var _babelTypes = require("babel-types");

var t = _interopRequireWildcard(_babelTypes);

var _invariant = require("../invariant.js");

var _invariant2 = _interopRequireDefault(_invariant);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } else { var newObj = {}; if (obj != null) { for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) newObj[key] = obj[key]; } } newObj.default = obj; return newObj; } }

function createAbstractValueForBinary(op, ast, lval, rval, lloc, rloc, leftCompletion, rightCompletion, resultValue, io, realm) {
  if (resultValue === undefined) {
    let resultType = (0, _BinaryExpression.getPureBinaryOperationResultType)(realm, op, lval, rval, lloc, rloc);
    if (resultType === undefined) {
      // The operation may result in side effects that we cannot track.
      // Since we have no idea what those effects are, we can either forget
      // (havoc) everything we know at this stage, or we can fault the
      // program and/or native model and stop evaluating.
      // We choose to do the latter.
      // TODO: report the error and carry on assuming no side effects.
      let val = lval instanceof _index.AbstractValue ? lval : rval;
      _index.AbstractValue.reportIntrospectionError(val);
      throw new _errors.FatalError();
    }
    resultValue = _index.AbstractValue.createFromBinaryOp(realm, op, lval, rval, ast.loc);
  }
  let r = _singletons.Join.composeNormalCompletions(leftCompletion, rightCompletion, resultValue, realm);
  return [r, ast, io];
} /**
   * Copyright (c) 2017-present, Facebook, Inc.
   * All rights reserved.
   *
   * This source code is licensed under the BSD-style license found in the
   * LICENSE file in the root directory of this source tree. An additional grant
   * of patent rights can be found in the PATENTS file in the same directory.
   */
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