Add iterator close support for for-of statement (#3401)

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu

jerry-core/ecma/base/ecma-gc.c

@@ -815,7 +815,7 @@ ecma_gc_free_executable_object (ecma_object_t *object_p) /**< object */
 
     do
     {
-      context_top_p[-1] &= (uint32_t) ~VM_CONTEXT_HAS_LEX_ENV;
+      context_top_p[-1] &= (uint32_t) ~(VM_CONTEXT_HAS_LEX_ENV | VM_CONTEXT_CLOSE_ITERATOR);
 
       uint32_t offsets = vm_get_context_value_offsets (context_top_p);
 

jerry-core/vm/vm-stack.c

@@ -18,6 +18,7 @@
 #include "ecma-helpers.h"
 #include "vm-defines.h"
 #include "vm-stack.h"
+#include "ecma-iterator-object.h"
 
 /** \addtogroup vm Virtual machine
  * @{
@@ -79,8 +80,15 @@ vm_stack_context_abort (vm_frame_ctx_t *frame_ctx_p, /**< frame context */
 #if ENABLED (JERRY_ES2015)
     case VM_CONTEXT_FOR_OF:
     {
+      ecma_value_t iterator = vm_stack_top_p[-3];
+
+      if (context_info & VM_CONTEXT_CLOSE_ITERATOR)
+      {
+        ecma_op_iterator_close (iterator);
+      }
+      ecma_free_value (iterator);
+
       ecma_free_value (vm_stack_top_p[-2]);
-      ecma_free_value (vm_stack_top_p[-3]);
       VM_MINUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION);
       vm_stack_top_p -= PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION;
       break;

jerry-core/vm/vm-stack.h

@@ -28,13 +28,13 @@
 /**
  * Create context on the vm stack.
  */
-#define VM_CREATE_CONTEXT(type, end_offset) ((ecma_value_t) ((type) | ((end_offset) << 6)))
+#define VM_CREATE_CONTEXT(type, end_offset) ((ecma_value_t) ((type) | ((end_offset) << 7)))
 
 /**
  * Create context on the vm stack with environment.
  */
 #define VM_CREATE_CONTEXT_WITH_ENV(type, end_offset) \
-  ((ecma_value_t) ((type) | ((end_offset) << 6) | VM_CONTEXT_HAS_LEX_ENV))
+  (VM_CREATE_CONTEXT ((type),(end_offset)) | VM_CONTEXT_HAS_LEX_ENV)
 
 /**
  * Get type of a vm context.
@@ -44,13 +44,18 @@
 /**
  * Get the end position of a vm context.
  */
-#define VM_GET_CONTEXT_END(value) ((value) >> 6)
+#define VM_GET_CONTEXT_END(value) ((value) >> 7)
 
 /**
  * This flag is set if the context has a lexical environment.
  */
 #define VM_CONTEXT_HAS_LEX_ENV 0x20
 
+/**
+ * This flag is set if the iterator close operation should be invoked during a for-of context break.
+ */
+#define VM_CONTEXT_CLOSE_ITERATOR 0x40
+
 /**
  * Context types for the vm stack.
  */

jerry-core/vm/vm.c

@@ -3485,7 +3485,7 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
 
           VM_PLUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION);
           stack_top_p += PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION;
-          stack_top_p[-1] = VM_CREATE_CONTEXT (VM_CONTEXT_FOR_OF, branch_offset);
+          stack_top_p[-1] = VM_CREATE_CONTEXT (VM_CONTEXT_FOR_OF, branch_offset) | VM_CONTEXT_CLOSE_ITERATOR;
           stack_top_p[-2] = next_value;
           stack_top_p[-3] = iterator;
 
@@ -3587,6 +3587,7 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
         case VM_OC_CONTEXT_END:
         {
           JERRY_ASSERT (VM_GET_REGISTERS (frame_ctx_p) + register_end + frame_ctx_p->context_depth == stack_top_p);
+          JERRY_ASSERT (!(stack_top_p[-1] & VM_CONTEXT_CLOSE_ITERATOR));
 
           ecma_value_t context_type = VM_GET_CONTEXT_TYPE (stack_top_p[-1]);
 
@@ -3653,6 +3654,7 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
         case VM_OC_JUMP_AND_EXIT_CONTEXT:
         {
           JERRY_ASSERT (VM_GET_REGISTERS (frame_ctx_p) + register_end + frame_ctx_p->context_depth == stack_top_p);
+          JERRY_ASSERT (!jcontext_has_pending_exception ());
 
           branch_offset += (int32_t) (byte_code_start_p - frame_ctx_p->byte_code_start_p);
 
@@ -3670,6 +3672,14 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
             byte_code_p = frame_ctx_p->byte_code_start_p + branch_offset;
           }
 
+#if ENABLED (JERRY_ES2015)
+          if (jcontext_has_pending_exception ())
+          {
+            result = ECMA_VALUE_ERROR;
+            goto error;
+          }
+#endif /* ENABLED (JERRY_ES2015) */
+
           JERRY_ASSERT (VM_GET_REGISTERS (frame_ctx_p) + register_end + frame_ctx_p->context_depth == stack_top_p);
           continue;
         }
@@ -3944,10 +3954,27 @@ error:
         JERRY_ASSERT (VM_GET_CONTEXT_TYPE (stack_top_p[-1]) == VM_CONTEXT_FINALLY_RETURN);
         JERRY_ASSERT (VM_GET_REGISTERS (frame_ctx_p) + register_end + frame_ctx_p->context_depth == stack_top_p);
 
+#if ENABLED (JERRY_ES2015)
+        if (jcontext_has_pending_exception ())
+        {
+          stack_top_p[-1] = (ecma_value_t) (stack_top_p[-1] - VM_CONTEXT_FINALLY_RETURN + VM_CONTEXT_FINALLY_THROW);
+          ecma_free_value (result);
+          result = jcontext_take_exception ();
+        }
+#endif /* ENABLED (JERRY_ES2015) */
+
         byte_code_p = frame_ctx_p->byte_code_p;
         stack_top_p[-2] = result;
         continue;
       }
+
+#if ENABLED (JERRY_ES2015)
+      if (jcontext_has_pending_exception ())
+      {
+        ecma_free_value (result);
+        result = ECMA_VALUE_ERROR;
+      }
+#endif /* ENABLED (JERRY_ES2015) */
     }
     else if (jcontext_has_pending_exception () && !jcontext_has_pending_abort ())
     {

tests/jerry/es2015/for-of-iterator-close.js

@@ -0,0 +1,244 @@
+// Copyright JS Foundation and other contributors, http://js.foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+function createIterable(arr, methods = {}) {
+  let iterable = function *() {
+    let idx = 0;
+    while (idx < arr.length) {
+      yield arr[idx];
+      idx++;
+    }
+  }();
+  iterable['return'] = methods['return'];
+  iterable['throw'] = methods['throw'];
+
+  return iterable;
+};
+
+function close1() {
+  var closed = false;
+  var iter = createIterable([1, 2, 3], {
+    'return': function() { closed = true; return {}; }
+  });
+  for (var it of iter) break;
+  return closed;
+}
+
+assert(close1());
+
+function close2() {
+  var closed = false;
+  var iter = createIterable([1, 2, 3], {
+    'return': function() { closed = true; return {}; }
+  });
+  try {
+    for (var it of iter) throw 0;
+    assert(false);
+  } catch(e){
+    assert(e === 0);
+  }
+  return closed;
+}
+
+assert(close2());
+
+function close3() {
+  var closed = false;
+  var iter = createIterable([1, 2, 3], {
+    'return': function() { closed = true; return {}; }
+  });
+  for (var it of iter) continue;
+  return closed;
+}
+
+assert(!close3());
+
+function close4() {
+  var closed = false;
+  var iter = createIterable([1, 2, 3], {
+    'return': function() { closed = true; throw 6; }
+  });
+  try {
+    for (var it of iter) throw 5;
+    assert(false);
+  } catch(e) {
+    assert(e === 5);
+  }
+  return closed;
+}
+
+assert(close4());
+
+function close5() {
+  var closed_called = 0;
+  var iter = createIterable([1, 2, 3], {
+    'return': function() { closed_called++; throw 6; }
+  });
+  try {
+    for (var it of iter) {
+      for (var it of iter) {
+        throw 5;
+      }
+      assert(false);
+    }
+    assert(false);
+  } catch(e) {
+    assert(e === 5);
+  }
+  return closed_called === 2;
+}
+
+assert(close5());
+
+function close6() {
+  var closed = false;
+  var iter = createIterable([1, 2, 3], {
+    'return': function() { closed = true; return {}; }
+  });
+  for (var it of iter) {};
+
+  return closed;
+}
+
+assert(!close6());
+
+var close7_result = false;
+function close7() {
+  var iter = createIterable([1, 2, 3], {
+    'return': function() { close7_result = true; throw "5"; }
+  });
+
+  for (var it of iter) {
+    return "foo";
+  }
+}
+
+try {
+  close7();
+  assert(false);
+} catch (e) {
+  assert(close7_result);
+  assert(e === "5");
+}
+
+function close8() {
+  var iter = createIterable([1, 2, 3], {
+    'return': function() { close8_result = true; throw "5"; }
+  });
+
+  for (var it of iter) {
+    throw "foo";
+  }
+}
+
+var close8_result = false;
+try {
+  close8();
+  assert(false);
+} catch (e) {
+  assert(e === "foo");
+  assert(close8_result);
+}
+
+function close9() {
+  var closed = false;
+  var iter = createIterable([1, 2, 3], {
+    'return': function() { closed = true; throw "5"; }
+  });
+
+  try {
+    for (var it of iter) {
+      break;
+    }
+  } finally {
+    assert(closed);
+    throw "foo"
+  }
+}
+
+try {
+  close9();
+  assert(false);
+} catch (e) {
+  assert(e === "foo");
+}
+
+function close10() {
+  var closed = false;
+  var iter = createIterable([1, 2, 3], {
+    'return': function() { closed = true; return {}; }
+  });
+
+  try {
+    for (var it of iter) {
+      return "foo";
+    }
+  } finally {
+    assert(closed);
+    throw "bar";
+  }
+}
+
+try {
+  close10();
+  assert(false);
+} catch (e) {
+  assert(e === "bar");
+}
+
+function close11() {
+  var closed = false;
+  var iter = createIterable([1, 2, 3], {
+    'return': function() { closed = true; throw "5"; }
+  });
+
+  try {
+    for (var it of iter) {
+      return "foo";
+    }
+  } finally {
+    assert(closed);
+    throw "bar";
+  }
+}
+
+try {
+  close11();
+  assert(false);
+} catch (e) {
+  assert(e === "bar");
+}
+
+function close12() {
+  var closed = false;
+  var iter = createIterable([1, 2, 3], {
+    'return': function() { closed = true; throw "5"; }
+  });
+
+  try {
+    for (var it of iter) {
+      throw "foo";
+    }
+  } finally {
+    assert(closed);
+    throw "bar";
+  }
+}
+
+try {
+  close12();
+  assert(false);
+} catch (e) {
+  assert(e === "bar");
+}