[Update] Fix accessing this before calling super

Siubaak · Nov 13, 2019 · 12d6708 · 12d6708
1 parent 722a65e
commit 12d6708
Show file tree

Hide file tree

Showing 3 changed files with 47 additions and 35 deletions.
diff --git a/src/compile/expression.ts b/src/compile/expression.ts
@@ -5,7 +5,7 @@ import { OP } from '../share/const'
 import { compileFunc, compileClass, compilePattern } from './helper'
 
 export function ThisExpression(node: estree.ThisExpression, state: State) {
-  state.opCodes.push({ op: OP.LOADV, val: state.symbols.get('this').pointer })
+  state.opCodes.push({ op: OP.LOADV, val: state.symbols.get('this').pointer, this: true })
 }
 
 export function ArrayExpression(node: estree.ArrayExpression, state: State) {

diff --git a/src/jsvm/index.ts b/src/jsvm/index.ts
@@ -8,7 +8,14 @@ function step(state: State) {
   let signal = SIGNAL.NONE
   switch (code.op) {
     case OP.LOADK: stack[state.esp++] = code.val; break
-    case OP.LOADV: stack[state.esp++] = state.context[code.val] && state.context[code.val].store; break
+    case OP.LOADV: {
+      const value = state.context[code.val] && state.context[code.val].store
+      if (code.this && value['#sval_super_called#'] === false) {
+        throw new ReferenceError("Must call super constructor in derived class before accessing 'this'")
+      }
+      stack[state.esp++] = value
+      break
+    }
     case OP.ALLOC: {
         const ebp = state.ebpList[state.ebpList.length - 1]
         const storeVal = state.esp > ebp ? stack[--state.esp] : undefined
@@ -301,9 +308,15 @@ function step(state: State) {
       }
       let ctor = function () {
         if  (classCtor) {
+          if (superClass) {
+            define(this, '#sval_super_called#', { value: false, configurable: true })
+          }
           const result = classCtor.apply(this, arguments)
-          if (superClass && !this['#sval_es6_class_super_called#']) {
-            throw new ReferenceError('Must call super constructor in derived class before returning from derived constructor')
+          if (superClass) {
+            if (!this['#sval_super_called#']) {
+              throw new ReferenceError('Must call super constructor in derived class before returning from derived constructor')
+            }
+            delete this['#sval_super_called#']
           }
           return result
         } else if (superClass) {
@@ -362,6 +375,13 @@ function step(state: State) {
 
       const obj = stack[--state.esp]
 
+      if (code.super) {
+        if (obj['#sval_super_called#']) {
+          throw new ReferenceError('Super constructor may only be called once')
+        }
+        define(obj, '#sval_super_called#', { value: true, configurable: true })
+      }
+
       const spread = code.val.concat()
       const newEsp = state.esp - spread.pop()
       const argsItems = stack.slice(newEsp, state.esp)
@@ -392,14 +412,6 @@ function step(state: State) {
       state.esp = state.ebpList.pop()
       stack[state.esp++] = result
 
-      if (code.super) {
-        if (obj['#sval_es6_class_super_called#']) {
-          throw new ReferenceError('Super constructor may only be called once')
-        } else {
-          define(obj, '#sval_es6_class_super_called#', { value: true })
-        }
-      }
-
       break
     }
     case OP.NEW: {

diff --git a/tests/class.test.ts b/tests/class.test.ts
@@ -262,31 +262,31 @@ describe('testing src/index.ts', () => {
     expect(interpreter.exports.y).toBe(1)
   })
 
-  // it('should throw ReferenceError when super() is not called before acessing this', () => {
-  //   const interpreter = new Sval()
-  //   let error = null
-  //   try {
-  //     interpreter.run(`
-  //       class X {
-  //         constructor() {
-  //           this.x = 1
-  //         }
-  //       }
+  it('should throw ReferenceError when super() is not called before acessing this', () => {
+    const interpreter = new Sval()
+    let error = null
+    try {
+      interpreter.run(`
+        class X {
+          constructor() {
+            this.x = 1
+          }
+        }
       
-  //       class Y extends X {
-  //         constructor() {
-  //           this.x = 2
-  //           super()
-  //         }
-  //       }
+        class Y extends X {
+          constructor() {
+            this.x = 2
+            super()
+          }
+        }
       
-  //       const y = new Y()
-  //     `)
-  //   } catch (err) {
-  //     error = err
-  //   }
-  //   expect(error).toBeInstanceOf(ReferenceError)
-  // })
+        const y = new Y()
+      `)
+    } catch (err) {
+      error = err
+    }
+    expect(error).toBeInstanceOf(ReferenceError)
+  })
 
   it('should throw ReferenceError when super() is not called in constructor for derived class', () => {
     const interpreter = new Sval()