Fix array initialization with array holes (#3076)

Fast mode access arrays must be converted back to normal if the array hole count reaches the limit during the initializtaion.
This patch fixes #3075.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik [email protected]

Author: rerobika

jerry-core/ecma/operations/ecma-array-object.c

@@ -186,13 +186,6 @@ ecma_fast_array_convert_to_normal (ecma_object_t *object_p) /**< fast access mod
   ecma_deref_object (object_p);
 } /* ecma_fast_array_convert_to_normal */
 
-/**
- * Maximum number of array holes in a fast mode access array.
- * If the number of holes exceeds this limit, the array is converted back
- * to normal property list based array.
- */
-#define ECMA_FAST_ARRAY_MAX_HOLE_COUNT 32
-
 #if ENABLED (JERRY_SYSTEM_ALLOCATOR)
 /**
  * Maximum length of the array length to allocate fast mode access for it

jerry-core/ecma/operations/ecma-array-object.h

@@ -25,6 +25,13 @@
  * @{
  */
 
+/**
+ * Maximum number of array holes in a fast mode access array.
+ * If the number of holes exceeds this limit, the array is converted back
+ * to normal property list based array.
+ */
+#define ECMA_FAST_ARRAY_MAX_HOLE_COUNT 32
+
 /**
  * Flags for ecma_op_array_object_set_length
  */

jerry-core/vm/vm.c

@@ -1668,23 +1668,58 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
           ecma_extended_object_t *ext_array_obj_p = (ecma_extended_object_t *) array_obj_p;
           uint32_t old_length = ext_array_obj_p->u.array.length;
 
-          JERRY_ASSERT (ext_array_obj_p->u.array.is_fast_mode);
+          if (JERRY_LIKELY (ext_array_obj_p->u.array.is_fast_mode))
+          {
+            ecma_value_t *values_p = ecma_fast_array_extend (array_obj_p, old_length + values_length);
 
-          ecma_value_t *values_p = ecma_fast_array_extend (array_obj_p, old_length + values_length);
+            for (uint32_t i = 0; i < values_length; i++)
+            {
+              values_p[old_length + i] = stack_top_p[i];
 
-          for (uint32_t i = 0; i < values_length; i++)
-          {
-            values_p[old_length + i] = stack_top_p[i];
+              if (JERRY_UNLIKELY (ecma_is_value_array_hole (stack_top_p[i])))
+              {
+                ext_array_obj_p->u.array.hole_count++;
+              }
+              else if (ecma_is_value_object (stack_top_p[i]))
+              {
+                ecma_deref_object (ecma_get_object_from_value (stack_top_p[i]));
+              }
+            }
 
-            if (JERRY_UNLIKELY (ecma_is_value_array_hole (stack_top_p[i])))
+            if (JERRY_UNLIKELY (ext_array_obj_p->u.array.length > ECMA_FAST_ARRAY_MAX_HOLE_COUNT))
             {
-              ext_array_obj_p->u.array.hole_count++;
+              ecma_fast_array_convert_to_normal (array_obj_p);
             }
-            else if (ecma_is_value_object (stack_top_p[i]))
+          }
+          else
+          {
+            for (uint32_t i = 0; i < values_length; i++)
             {
-              ecma_deref_object (ecma_get_object_from_value (stack_top_p[i]));
+              if (!ecma_is_value_array_hole (stack_top_p[i]))
+              {
+                ecma_string_t *index_str_p = ecma_new_ecma_string_from_uint32 (old_length + i);
+
+                ecma_property_value_t *prop_value_p;
+
+                prop_value_p = ecma_create_named_data_property (array_obj_p,
+                                                                index_str_p,
+                                                                ECMA_PROPERTY_CONFIGURABLE_ENUMERABLE_WRITABLE,
+                                                                NULL);
+
+                ecma_deref_ecma_string (index_str_p);
+                prop_value_p->value = stack_top_p[i];
+
+                if (ecma_is_value_object (stack_top_p[i]))
+                {
+                  ecma_free_value (stack_top_p[i]);
+                }
+
+              }
             }
+
+            ext_array_obj_p->u.array.length = old_length + values_length;
           }
+
           continue;
         }
         case VM_OC_PUSH_UNDEFINED_BASE:

tests/jerry/regression-test-issue-3072.js

@@ -0,0 +1,18 @@
+// 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.
+
+var arr = [ , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ];
+arr [4294967294] = 0
+assert (arr.length === 4294967295);
+assert (arr[4294967294] === 0);