switch to vuepress

6 files changed, 990 insertions, 0 deletions

diff --git a/node_modules/@webassemblyjs/helper-module-context/LICENSE b/node_modules/@webassemblyjs/helper-module-context/LICENSE
new file mode 100644
index 00000000..87e7e1ff
--- /dev/null
+++ b/node_modules/@webassemblyjs/helper-module-context/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2018 Sven Sauleau <sven@sauleau.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/node_modules/@webassemblyjs/helper-module-context/esm/index.js b/node_modules/@webassemblyjs/helper-module-context/esm/index.js
new file mode 100644
index 00000000..66e2d7cb
--- /dev/null
+++ b/node_modules/@webassemblyjs/helper-module-context/esm/index.js
@@ -0,0 +1,326 @@
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
+
+function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }
+
+function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); return Constructor; }
+
+// TODO(sven): add flow in here
+export function moduleContextFromModuleAST(m) {
+  var moduleContext = new ModuleContext();
+
+  if (!(m.type === "Module")) {
+    throw new Error('m.type === "Module"' + " error: " + (undefined || "unknown"));
+  }
+
+  m.fields.forEach(function (field) {
+    switch (field.type) {
+      case "Start":
+        {
+          moduleContext.setStart(field.index);
+        }
+
+      case "Func":
+        {
+          moduleContext.addFunction(field);
+          break;
+        }
+
+      case "Global":
+        {
+          moduleContext.defineGlobal(field);
+          break;
+        }
+
+      case "ModuleImport":
+        {
+          switch (field.descr.type) {
+            case "GlobalType":
+              {
+                moduleContext.importGlobal(field.descr.valtype, field.descr.mutability);
+                break;
+              }
+
+            case "Memory":
+              {
+                moduleContext.addMemory(field.descr.limits.min, field.descr.limits.max);
+                break;
+              }
+
+            case "FuncImportDescr":
+              {
+                moduleContext.importFunction(field.descr);
+                break;
+              }
+
+            case "Table":
+              {
+                // FIXME(sven): not implemented yet
+                break;
+              }
+
+            default:
+              throw new Error("Unsupported ModuleImport of type " + JSON.stringify(field.descr.type));
+          }
+
+          break;
+        }
+
+      case "Memory":
+        {
+          moduleContext.addMemory(field.limits.min, field.limits.max);
+          break;
+        }
+    }
+  });
+  return moduleContext;
+}
+/**
+ * Module context for type checking
+ */
+
+export var ModuleContext =
+/*#__PURE__*/
+function () {
+  function ModuleContext() {
+    _classCallCheck(this, ModuleContext);
+
+    this.funcs = [];
+    this.funcsOffsetByIdentifier = [];
+    this.globals = [];
+    this.globalsOffsetByIdentifier = [];
+    this.mems = []; // Current stack frame
+
+    this.locals = [];
+    this.labels = [];
+    this.return = [];
+    this.debugName = "unknown";
+    this.start = null;
+  }
+  /**
+   * Set start segment
+   */
+
+
+  _createClass(ModuleContext, [{
+    key: "setStart",
+    value: function setStart(index) {
+      this.start = index.value;
+    }
+    /**
+     * Get start function
+     */
+
+  }, {
+    key: "getStart",
+    value: function getStart() {
+      return this.start;
+    }
+    /**
+     * Reset the active stack frame
+     */
+
+  }, {
+    key: "newContext",
+    value: function newContext(debugName, expectedResult) {
+      this.locals = [];
+      this.labels = [expectedResult];
+      this.return = expectedResult;
+      this.debugName = debugName;
+    }
+    /**
+     * Functions
+     */
+
+  }, {
+    key: "addFunction",
+    value: function addFunction(func
+    /*: Func*/
+    ) {
+      // eslint-disable-next-line prefer-const
+      var _ref = func.signature || {},
+          _ref$params = _ref.params,
+          args = _ref$params === void 0 ? [] : _ref$params,
+          _ref$results = _ref.results,
+          result = _ref$results === void 0 ? [] : _ref$results;
+
+      args = args.map(function (arg) {
+        return arg.valtype;
+      });
+      this.funcs.push({
+        args: args,
+        result: result
+      });
+
+      if (typeof func.name !== "undefined") {
+        this.funcsOffsetByIdentifier[func.name.value] = this.funcs.length - 1;
+      }
+    }
+  }, {
+    key: "importFunction",
+    value: function importFunction(funcimport) {
+      // eslint-disable-next-line prefer-const
+      var _funcimport$signature = funcimport.signature,
+          args = _funcimport$signature.params,
+          result = _funcimport$signature.results;
+      args = args.map(function (arg) {
+        return arg.valtype;
+      });
+      this.funcs.push({
+        args: args,
+        result: result
+      });
+
+      if (typeof funcimport.id !== "undefined") {
+        // imports are first, we can assume their index in the array
+        this.funcsOffsetByIdentifier[funcimport.id.value] = this.funcs.length - 1;
+      }
+    }
+  }, {
+    key: "hasFunction",
+    value: function hasFunction(index) {
+      return typeof this.getFunction(index) !== "undefined";
+    }
+  }, {
+    key: "getFunction",
+    value: function getFunction(index) {
+      if (typeof index !== "number") {
+        throw new Error("getFunction only supported for number index");
+      }
+
+      return this.funcs[index];
+    }
+  }, {
+    key: "getFunctionOffsetByIdentifier",
+    value: function getFunctionOffsetByIdentifier(name) {
+      if (!(typeof name === "string")) {
+        throw new Error('typeof name === "string"' + " error: " + (undefined || "unknown"));
+      }
+
+      return this.funcsOffsetByIdentifier[name];
+    }
+    /**
+     * Labels
+     */
+
+  }, {
+    key: "addLabel",
+    value: function addLabel(result) {
+      this.labels.unshift(result);
+    }
+  }, {
+    key: "hasLabel",
+    value: function hasLabel(index) {
+      return this.labels.length > index && index >= 0;
+    }
+  }, {
+    key: "getLabel",
+    value: function getLabel(index) {
+      return this.labels[index];
+    }
+  }, {
+    key: "popLabel",
+    value: function popLabel() {
+      this.labels.shift();
+    }
+    /**
+     * Locals
+     */
+
+  }, {
+    key: "hasLocal",
+    value: function hasLocal(index) {
+      return typeof this.getLocal(index) !== "undefined";
+    }
+  }, {
+    key: "getLocal",
+    value: function getLocal(index) {
+      return this.locals[index];
+    }
+  }, {
+    key: "addLocal",
+    value: function addLocal(type) {
+      this.locals.push(type);
+    }
+    /**
+     * Globals
+     */
+
+  }, {
+    key: "hasGlobal",
+    value: function hasGlobal(index) {
+      return this.globals.length > index && index >= 0;
+    }
+  }, {
+    key: "getGlobal",
+    value: function getGlobal(index) {
+      return this.globals[index].type;
+    }
+  }, {
+    key: "getGlobalOffsetByIdentifier",
+    value: function getGlobalOffsetByIdentifier(name) {
+      if (!(typeof name === "string")) {
+        throw new Error('typeof name === "string"' + " error: " + (undefined || "unknown"));
+      }
+
+      return this.globalsOffsetByIdentifier[name];
+    }
+  }, {
+    key: "defineGlobal",
+    value: function defineGlobal(global
+    /*: Global*/
+    ) {
+      var type = global.globalType.valtype;
+      var mutability = global.globalType.mutability;
+      this.globals.push({
+        type: type,
+        mutability: mutability
+      });
+
+      if (typeof global.name !== "undefined") {
+        this.globalsOffsetByIdentifier[global.name.value] = this.globals.length - 1;
+      }
+    }
+  }, {
+    key: "importGlobal",
+    value: function importGlobal(type, mutability) {
+      this.globals.push({
+        type: type,
+        mutability: mutability
+      });
+    }
+  }, {
+    key: "isMutableGlobal",
+    value: function isMutableGlobal(index) {
+      return this.globals[index].mutability === "var";
+    }
+  }, {
+    key: "isImmutableGlobal",
+    value: function isImmutableGlobal(index) {
+      return this.globals[index].mutability === "const";
+    }
+    /**
+     * Memories
+     */
+
+  }, {
+    key: "hasMemory",
+    value: function hasMemory(index) {
+      return this.mems.length > index && index >= 0;
+    }
+  }, {
+    key: "addMemory",
+    value: function addMemory(min, max) {
+      this.mems.push({
+        min: min,
+        max: max
+      });
+    }
+  }, {
+    key: "getMemory",
+    value: function getMemory(index) {
+      return this.mems[index];
+    }
+  }]);
+
+  return ModuleContext;
+}();
\ No newline at end of file
diff --git a/node_modules/@webassemblyjs/helper-module-context/lib/index.js b/node_modules/@webassemblyjs/helper-module-context/lib/index.js
new file mode 100644
index 00000000..93e0880d
--- /dev/null
+++ b/node_modules/@webassemblyjs/helper-module-context/lib/index.js
@@ -0,0 +1,337 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.moduleContextFromModuleAST = moduleContextFromModuleAST;
+exports.ModuleContext = void 0;
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
+
+function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }
+
+function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); return Constructor; }
+
+// TODO(sven): add flow in here
+function moduleContextFromModuleAST(m) {
+  var moduleContext = new ModuleContext();
+
+  if (!(m.type === "Module")) {
+    throw new Error('m.type === "Module"' + " error: " + (undefined || "unknown"));
+  }
+
+  m.fields.forEach(function (field) {
+    switch (field.type) {
+      case "Start":
+        {
+          moduleContext.setStart(field.index);
+        }
+
+      case "Func":
+        {
+          moduleContext.addFunction(field);
+          break;
+        }
+
+      case "Global":
+        {
+          moduleContext.defineGlobal(field);
+          break;
+        }
+
+      case "ModuleImport":
+        {
+          switch (field.descr.type) {
+            case "GlobalType":
+              {
+                moduleContext.importGlobal(field.descr.valtype, field.descr.mutability);
+                break;
+              }
+
+            case "Memory":
+              {
+                moduleContext.addMemory(field.descr.limits.min, field.descr.limits.max);
+                break;
+              }
+
+            case "FuncImportDescr":
+              {
+                moduleContext.importFunction(field.descr);
+                break;
+              }
+
+            case "Table":
+              {
+                // FIXME(sven): not implemented yet
+                break;
+              }
+
+            default:
+              throw new Error("Unsupported ModuleImport of type " + JSON.stringify(field.descr.type));
+          }
+
+          break;
+        }
+
+      case "Memory":
+        {
+          moduleContext.addMemory(field.limits.min, field.limits.max);
+          break;
+        }
+    }
+  });
+  return moduleContext;
+}
+/**
+ * Module context for type checking
+ */
+
+
+var ModuleContext =
+/*#__PURE__*/
+function () {
+  function ModuleContext() {
+    _classCallCheck(this, ModuleContext);
+
+    this.funcs = [];
+    this.funcsOffsetByIdentifier = [];
+    this.globals = [];
+    this.globalsOffsetByIdentifier = [];
+    this.mems = []; // Current stack frame
+
+    this.locals = [];
+    this.labels = [];
+    this.return = [];
+    this.debugName = "unknown";
+    this.start = null;
+  }
+  /**
+   * Set start segment
+   */
+
+
+  _createClass(ModuleContext, [{
+    key: "setStart",
+    value: function setStart(index) {
+      this.start = index.value;
+    }
+    /**
+     * Get start function
+     */
+
+  }, {
+    key: "getStart",
+    value: function getStart() {
+      return this.start;
+    }
+    /**
+     * Reset the active stack frame
+     */
+
+  }, {
+    key: "newContext",
+    value: function newContext(debugName, expectedResult) {
+      this.locals = [];
+      this.labels = [expectedResult];
+      this.return = expectedResult;
+      this.debugName = debugName;
+    }
+    /**
+     * Functions
+     */
+
+  }, {
+    key: "addFunction",
+    value: function addFunction(func
+    /*: Func*/
+    ) {
+      // eslint-disable-next-line prefer-const
+      var _ref = func.signature || {},
+          _ref$params = _ref.params,
+          args = _ref$params === void 0 ? [] : _ref$params,
+          _ref$results = _ref.results,
+          result = _ref$results === void 0 ? [] : _ref$results;
+
+      args = args.map(function (arg) {
+        return arg.valtype;
+      });
+      this.funcs.push({
+        args: args,
+        result: result
+      });
+
+      if (typeof func.name !== "undefined") {
+        this.funcsOffsetByIdentifier[func.name.value] = this.funcs.length - 1;
+      }
+    }
+  }, {
+    key: "importFunction",
+    value: function importFunction(funcimport) {
+      // eslint-disable-next-line prefer-const
+      var _funcimport$signature = funcimport.signature,
+          args = _funcimport$signature.params,
+          result = _funcimport$signature.results;
+      args = args.map(function (arg) {
+        return arg.valtype;
+      });
+      this.funcs.push({
+        args: args,
+        result: result
+      });
+
+      if (typeof funcimport.id !== "undefined") {
+        // imports are first, we can assume their index in the array
+        this.funcsOffsetByIdentifier[funcimport.id.value] = this.funcs.length - 1;
+      }
+    }
+  }, {
+    key: "hasFunction",
+    value: function hasFunction(index) {
+      return typeof this.getFunction(index) !== "undefined";
+    }
+  }, {
+    key: "getFunction",
+    value: function getFunction(index) {
+      if (typeof index !== "number") {
+        throw new Error("getFunction only supported for number index");
+      }
+
+      return this.funcs[index];
+    }
+  }, {
+    key: "getFunctionOffsetByIdentifier",
+    value: function getFunctionOffsetByIdentifier(name) {
+      if (!(typeof name === "string")) {
+        throw new Error('typeof name === "string"' + " error: " + (undefined || "unknown"));
+      }
+
+      return this.funcsOffsetByIdentifier[name];
+    }
+    /**
+     * Labels
+     */
+
+  }, {
+    key: "addLabel",
+    value: function addLabel(result) {
+      this.labels.unshift(result);
+    }
+  }, {
+    key: "hasLabel",
+    value: function hasLabel(index) {
+      return this.labels.length > index && index >= 0;
+    }
+  }, {
+    key: "getLabel",
+    value: function getLabel(index) {
+      return this.labels[index];
+    }
+  }, {
+    key: "popLabel",
+    value: function popLabel() {
+      this.labels.shift();
+    }
+    /**
+     * Locals
+     */
+
+  }, {
+    key: "hasLocal",
+    value: function hasLocal(index) {
+      return typeof this.getLocal(index) !== "undefined";
+    }
+  }, {
+    key: "getLocal",
+    value: function getLocal(index) {
+      return this.locals[index];
+    }
+  }, {
+    key: "addLocal",
+    value: function addLocal(type) {
+      this.locals.push(type);
+    }
+    /**
+     * Globals
+     */
+
+  }, {
+    key: "hasGlobal",
+    value: function hasGlobal(index) {
+      return this.globals.length > index && index >= 0;
+    }
+  }, {
+    key: "getGlobal",
+    value: function getGlobal(index) {
+      return this.globals[index].type;
+    }
+  }, {
+    key: "getGlobalOffsetByIdentifier",
+    value: function getGlobalOffsetByIdentifier(name) {
+      if (!(typeof name === "string")) {
+        throw new Error('typeof name === "string"' + " error: " + (undefined || "unknown"));
+      }
+
+      return this.globalsOffsetByIdentifier[name];
+    }
+  }, {
+    key: "defineGlobal",
+    value: function defineGlobal(global
+    /*: Global*/
+    ) {
+      var type = global.globalType.valtype;
+      var mutability = global.globalType.mutability;
+      this.globals.push({
+        type: type,
+        mutability: mutability
+      });
+
+      if (typeof global.name !== "undefined") {
+        this.globalsOffsetByIdentifier[global.name.value] = this.globals.length - 1;
+      }
+    }
+  }, {
+    key: "importGlobal",
+    value: function importGlobal(type, mutability) {
+      this.globals.push({
+        type: type,
+        mutability: mutability
+      });
+    }
+  }, {
+    key: "isMutableGlobal",
+    value: function isMutableGlobal(index) {
+      return this.globals[index].mutability === "var";
+    }
+  }, {
+    key: "isImmutableGlobal",
+    value: function isImmutableGlobal(index) {
+      return this.globals[index].mutability === "const";
+    }
+    /**
+     * Memories
+     */
+
+  }, {
+    key: "hasMemory",
+    value: function hasMemory(index) {
+      return this.mems.length > index && index >= 0;
+    }
+  }, {
+    key: "addMemory",
+    value: function addMemory(min, max) {
+      this.mems.push({
+        min: min,
+        max: max
+      });
+    }
+  }, {
+    key: "getMemory",
+    value: function getMemory(index) {
+      return this.mems[index];
+    }
+  }]);
+
+  return ModuleContext;
+}();
+
+exports.ModuleContext = ModuleContext;
\ No newline at end of file
diff --git a/node_modules/@webassemblyjs/helper-module-context/package.json b/node_modules/@webassemblyjs/helper-module-context/package.json
new file mode 100644
index 00000000..d0143b5b
--- /dev/null
+++ b/node_modules/@webassemblyjs/helper-module-context/package.json
@@ -0,0 +1,24 @@
+{
+  "name": "@webassemblyjs/helper-module-context",
+  "version": "1.7.11",
+  "description": "",
+  "main": "lib/index.js",
+  "module": "esm/index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/xtuc/webassemblyjs.git"
+  },
+  "devDependencies": {
+    "@webassemblyjs/wast-parser": "1.7.11",
+    "mamacro": "^0.0.3"
+  },
+  "publishConfig": {
+    "access": "public"
+  },
+  "author": "Sven Sauleau",
+  "license": "MIT",
+  "gitHead": "4291990bfc4648bc6676091a955d12dc3c7e5909"
+}
diff --git a/node_modules/@webassemblyjs/helper-module-context/src/index.js b/node_modules/@webassemblyjs/helper-module-context/src/index.js
new file mode 100644
index 00000000..2025cc32
--- /dev/null
+++ b/node_modules/@webassemblyjs/helper-module-context/src/index.js
@@ -0,0 +1,250 @@
+// TODO(sven): add flow in here
+
+import { assert } from "mamacro";
+
+export function moduleContextFromModuleAST(m) {
+  const moduleContext = new ModuleContext();
+
+  assert(m.type === "Module");
+
+  m.fields.forEach(field => {
+    switch (field.type) {
+      case "Start": {
+        moduleContext.setStart(field.index);
+      }
+      case "Func": {
+        moduleContext.addFunction(field);
+        break;
+      }
+      case "Global": {
+        moduleContext.defineGlobal(field);
+        break;
+      }
+      case "ModuleImport": {
+        switch (field.descr.type) {
+          case "GlobalType": {
+            moduleContext.importGlobal(
+              field.descr.valtype,
+              field.descr.mutability
+            );
+            break;
+          }
+          case "Memory": {
+            moduleContext.addMemory(
+              field.descr.limits.min,
+              field.descr.limits.max
+            );
+            break;
+          }
+          case "FuncImportDescr": {
+            moduleContext.importFunction(field.descr);
+            break;
+          }
+
+          case "Table": {
+            // FIXME(sven): not implemented yet
+            break;
+          }
+
+          default:
+            throw new Error(
+              "Unsupported ModuleImport of type " +
+                JSON.stringify(field.descr.type)
+            );
+        }
+        break;
+      }
+      case "Memory": {
+        moduleContext.addMemory(field.limits.min, field.limits.max);
+        break;
+      }
+    }
+  });
+
+  return moduleContext;
+}
+
+/**
+ * Module context for type checking
+ */
+export class ModuleContext {
+  constructor() {
+    this.funcs = [];
+    this.funcsOffsetByIdentifier = [];
+
+    this.globals = [];
+    this.globalsOffsetByIdentifier = [];
+
+    this.mems = [];
+
+    // Current stack frame
+    this.locals = [];
+    this.labels = [];
+    this.return = [];
+
+    this.debugName = "unknown";
+
+    this.start = null;
+  }
+
+  /**
+   * Set start segment
+   */
+  setStart(index) {
+    this.start = index.value;
+  }
+
+  /**
+   * Get start function
+   */
+  getStart() {
+    return this.start;
+  }
+
+  /**
+   * Reset the active stack frame
+   */
+  newContext(debugName, expectedResult) {
+    this.locals = [];
+    this.labels = [expectedResult];
+    this.return = expectedResult;
+    this.debugName = debugName;
+  }
+
+  /**
+   * Functions
+   */
+  addFunction(func /*: Func*/) {
+    // eslint-disable-next-line prefer-const
+    let { params: args = [], results: result = [] } = func.signature || {};
+
+    args = args.map(arg => arg.valtype);
+
+    this.funcs.push({ args, result });
+
+    if (typeof func.name !== "undefined") {
+      this.funcsOffsetByIdentifier[func.name.value] = this.funcs.length - 1;
+    }
+  }
+
+  importFunction(funcimport) {
+    // eslint-disable-next-line prefer-const
+    let { params: args, results: result } = funcimport.signature;
+    args = args.map(arg => arg.valtype);
+
+    this.funcs.push({ args, result });
+
+    if (typeof funcimport.id !== "undefined") {
+      // imports are first, we can assume their index in the array
+      this.funcsOffsetByIdentifier[funcimport.id.value] = this.funcs.length - 1;
+    }
+  }
+
+  hasFunction(index) {
+    return typeof this.getFunction(index) !== "undefined";
+  }
+
+  getFunction(index) {
+    if (typeof index !== "number") {
+      throw new Error("getFunction only supported for number index");
+    }
+
+    return this.funcs[index];
+  }
+
+  getFunctionOffsetByIdentifier(name) {
+    assert(typeof name === "string");
+
+    return this.funcsOffsetByIdentifier[name];
+  }
+
+  /**
+   * Labels
+   */
+  addLabel(result) {
+    this.labels.unshift(result);
+  }
+
+  hasLabel(index) {
+    return this.labels.length > index && index >= 0;
+  }
+
+  getLabel(index) {
+    return this.labels[index];
+  }
+
+  popLabel() {
+    this.labels.shift();
+  }
+
+  /**
+   * Locals
+   */
+  hasLocal(index) {
+    return typeof this.getLocal(index) !== "undefined";
+  }
+
+  getLocal(index) {
+    return this.locals[index];
+  }
+
+  addLocal(type) {
+    this.locals.push(type);
+  }
+
+  /**
+   * Globals
+   */
+  hasGlobal(index) {
+    return this.globals.length > index && index >= 0;
+  }
+
+  getGlobal(index) {
+    return this.globals[index].type;
+  }
+
+  getGlobalOffsetByIdentifier(name) {
+    assert(typeof name === "string");
+
+    return this.globalsOffsetByIdentifier[name];
+  }
+
+  defineGlobal(global /*: Global*/) {
+    const type = global.globalType.valtype;
+    const mutability = global.globalType.mutability;
+
+    this.globals.push({ type, mutability });
+
+    if (typeof global.name !== "undefined") {
+      this.globalsOffsetByIdentifier[global.name.value] =
+        this.globals.length - 1;
+    }
+  }
+
+  importGlobal(type, mutability) {
+    this.globals.push({ type, mutability });
+  }
+
+  isMutableGlobal(index) {
+    return this.globals[index].mutability === "var";
+  }
+
+  isImmutableGlobal(index) {
+    return this.globals[index].mutability === "const";
+  }
+
+  /**
+   * Memories
+   */
+  hasMemory(index) {
+    return this.mems.length > index && index >= 0;
+  }
+
+  addMemory(min, max) {
+    this.mems.push({ min, max });
+  }
+
+  getMemory(index) {
+    return this.mems[index];
+  }
+}
diff --git a/node_modules/@webassemblyjs/helper-module-context/test/index.js b/node_modules/@webassemblyjs/helper-module-context/test/index.js
new file mode 100644
index 00000000..06005d60
--- /dev/null
+++ b/node_modules/@webassemblyjs/helper-module-context/test/index.js
@@ -0,0 +1,32 @@
+const { assert } = require("chai");
+const { parse } = require("@webassemblyjs/wast-parser");
+
+const { moduleContextFromModuleAST } = require("../lib");
+
+const contextFromWast = wast => moduleContextFromModuleAST(parse(wast).body[0]);
+
+describe("module context", () => {
+  describe("start segment", () => {
+    it("should return the start function offset", () => {
+      const context = contextFromWast(`
+        (module
+          (func)
+          (func)
+          (start 1)
+        )
+      `);
+
+      assert.isOk(context.getStart());
+      assert.typeOf(context.getStart(), "number");
+      assert.equal(context.getStart(), 1);
+    });
+
+    it("should return null if no start function", () => {
+      const context = contextFromWast(`
+        (module (func))
+      `);
+
+      assert.isNull(context.getStart());
+    });
+  });
+});