Implement the core of the generator functions. (#3368)

Some things are missing:
 - yield* support
 - generator definition in object literal
 - the hidden GeneratorFunction

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com

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

@@ -293,6 +293,7 @@ ecma_gc_mark_promise_object (ecma_extended_object_t *ext_object_p) /**< extended
 #endif /* ENABLED (JERRY_ES2015_BUILTIN_PROMISE) */
 
 #if ENABLED (JERRY_ES2015_BUILTIN_CONTAINER)
+
 /**
  * Mark objects referenced by Map/Set built-in.
  */
@@ -359,6 +360,73 @@ ecma_gc_mark_container_object (ecma_object_t *object_p) /**< object */
 
 #endif /* ENABLED (JERRY_ES2015_BUILTIN_CONTAINER) */
 
+#if ENABLED (JERRY_ES2015)
+
+/**
+ * Mark objects referenced by inactive generator functions, async functions, etc.
+ */
+static void
+ecma_gc_mark_executable_object (ecma_object_t *object_p) /**< object */
+{
+  vm_executable_object_t *executable_object_p = (vm_executable_object_t *) object_p;
+
+  if (!ECMA_EXECUTABLE_OBJECT_IS_SUSPENDED (executable_object_p->extended_object.u.class_prop.extra_info))
+  {
+    /* All objects referenced by running executable objects are strong roots,
+     * and a finished executable object cannot refer to other values. */
+    return;
+  }
+
+  ecma_gc_set_object_visited (executable_object_p->frame_ctx.lex_env_p);
+
+  if (ecma_is_value_object (executable_object_p->frame_ctx.this_binding))
+  {
+    ecma_gc_set_object_visited (ecma_get_object_from_value (executable_object_p->frame_ctx.this_binding));
+  }
+
+  const ecma_compiled_code_t *bytecode_header_p = executable_object_p->frame_ctx.bytecode_header_p;
+  size_t register_end;
+
+  if (bytecode_header_p->status_flags & CBC_CODE_FLAGS_UINT16_ARGUMENTS)
+  {
+    cbc_uint16_arguments_t *args_p = (cbc_uint16_arguments_t *) bytecode_header_p;
+    register_end = args_p->register_end;
+  }
+  else
+  {
+    cbc_uint8_arguments_t *args_p = (cbc_uint8_arguments_t *) bytecode_header_p;
+    register_end = args_p->register_end;
+  }
+
+  ecma_value_t *register_p = VM_GET_REGISTERS (&executable_object_p->frame_ctx);
+  ecma_value_t *register_end_p = register_p + register_end;
+
+  while (register_p < register_end_p)
+  {
+    if (ecma_is_value_object (*register_p))
+    {
+      ecma_gc_set_object_visited (ecma_get_object_from_value (*register_p));
+    }
+
+    register_p++;
+  }
+
+  register_p += executable_object_p->frame_ctx.context_depth;
+  register_end_p = executable_object_p->frame_ctx.stack_top_p;
+
+  while (register_p < register_end_p)
+  {
+    if (ecma_is_value_object (*register_p))
+    {
+      ecma_gc_set_object_visited (ecma_get_object_from_value (*register_p));
+    }
+
+    register_p++;
+  }
+} /* ecma_gc_mark_executable_object */
+
+#endif /* ENABLED (JERRY_ES2015) */
+
 /**
  * Mark objects as visited starting from specified object as root
  */
@@ -435,6 +503,13 @@ ecma_gc_mark (ecma_object_t *object_p) /**< object to mark from */
             break;
           }
 #endif /* ENABLED (JERRY_ES2015_BUILTIN_CONTAINER) */
+#if ENABLED (JERRY_ES2015)
+          case LIT_MAGIC_STRING_GENERATOR_UL:
+          {
+            ecma_gc_mark_executable_object (object_p);
+            break;
+          }
+#endif /* ENABLED (JERRY_ES2015) */
           default:
           {
             break;
@@ -641,6 +716,100 @@ ecma_free_fast_access_array (ecma_object_t *object_p) /**< fast access mode arra
   ecma_dealloc_extended_object (object_p, sizeof (ecma_extended_object_t));
 } /* ecma_free_fast_access_array */
 
+#if ENABLED (JERRY_ES2015)
+
+/**
+ * Free non-objects referenced by inactive generator functions, async functions, etc.
+ *
+ * @return total object size
+ */
+static size_t
+ecma_gc_free_executable_object (ecma_object_t *object_p) /**< object */
+{
+  vm_executable_object_t *executable_object_p = (vm_executable_object_t *) object_p;
+
+  const ecma_compiled_code_t *bytecode_header_p = executable_object_p->frame_ctx.bytecode_header_p;
+  size_t size, register_end;
+
+  if (bytecode_header_p->status_flags & CBC_CODE_FLAGS_UINT16_ARGUMENTS)
+  {
+    cbc_uint16_arguments_t *args_p = (cbc_uint16_arguments_t *) bytecode_header_p;
+
+    register_end = args_p->register_end;
+    size = (register_end + (size_t) args_p->stack_limit) * sizeof (ecma_value_t);
+  }
+  else
+  {
+    cbc_uint8_arguments_t *args_p = (cbc_uint8_arguments_t *) bytecode_header_p;
+
+    register_end = args_p->register_end;
+    size = (register_end + (size_t) args_p->stack_limit) * sizeof (ecma_value_t);
+  }
+
+  size = JERRY_ALIGNUP (sizeof (vm_executable_object_t) + size, sizeof (uintptr_t));
+
+  JERRY_ASSERT (!(executable_object_p->extended_object.u.class_prop.extra_info & ECMA_EXECUTABLE_OBJECT_RUNNING));
+
+  ecma_bytecode_deref ((ecma_compiled_code_t *) bytecode_header_p);
+
+  if (executable_object_p->extended_object.u.class_prop.extra_info & ECMA_EXECUTABLE_OBJECT_COMPLETED)
+  {
+    return size;
+  }
+
+  ecma_free_value_if_not_object (executable_object_p->frame_ctx.this_binding);
+
+  ecma_value_t *register_p = VM_GET_REGISTERS (&executable_object_p->frame_ctx);
+  ecma_value_t *register_end_p = register_p + register_end;
+
+  while (register_p < register_end_p)
+  {
+    ecma_free_value_if_not_object (*register_p++);
+  }
+
+  if (executable_object_p->frame_ctx.context_depth > 0)
+  {
+    ecma_value_t *context_end_p = register_p;
+
+    register_p += executable_object_p->frame_ctx.context_depth;
+
+    ecma_value_t *context_top_p = register_p;
+
+    do
+    {
+      context_top_p[-1] &= (uint32_t) ~VM_CONTEXT_HAS_LEX_ENV;
+
+      uint32_t offsets = vm_get_context_value_offsets (context_top_p);
+
+      while (VM_CONTEXT_HAS_NEXT_OFFSET (offsets))
+      {
+        int32_t offset = VM_CONTEXT_GET_NEXT_OFFSET (offsets);
+
+        if (ecma_is_value_object (context_top_p[offset]))
+        {
+          context_top_p[offset] = ECMA_VALUE_UNDEFINED;
+        }
+
+        offsets >>= VM_CONTEXT_OFFSET_SHIFT;
+      }
+
+      context_top_p = vm_stack_context_abort (&executable_object_p->frame_ctx, context_top_p);
+    }
+    while (context_top_p > context_end_p);
+  }
+
+  register_end_p = executable_object_p->frame_ctx.stack_top_p;
+
+  while (register_p < register_end_p)
+  {
+    ecma_free_value_if_not_object (*register_p++);
+  }
+
+  return size;
+} /* ecma_gc_free_executable_object */
+
+#endif /* ENABLED (JERRY_ES2015) */
+
 /**
  * Free properties of an object
  */
@@ -930,6 +1099,13 @@ ecma_gc_free_object (ecma_object_t *object_p) /**< object to free */
           break;
         }
 #endif /* ENABLED (JERRY_ES2015_BUILTIN_DATAVIEW) */
+#if ENABLED (JERRY_ES2015)
+        case LIT_MAGIC_STRING_GENERATOR_UL:
+        {
+          ext_object_size = ecma_gc_free_executable_object (object_p);
+          break;
+        }
+#endif /* ENABLED (JERRY_ES2015) */
         default:
         {
           /* The undefined id represents an uninitialized class. */

jerry-core/ecma/base/ecma-globals.h

@@ -1750,6 +1750,35 @@ typedef struct
 
 #endif /* ENABLED (JERRY_ES2015_BUILTIN_TYPEDARRAY) */
 
+#if ENABLED (JERRY_ES2015)
+
+/**
+ * Executable (e.g. generator, async) object flags.
+ */
+typedef enum
+{
+  ECMA_EXECUTABLE_OBJECT_COMPLETED = (1u << 0), /**< executable object is completed and cannot be resumed */
+  ECMA_EXECUTABLE_OBJECT_RUNNING = (1u << 1), /**< executable object is currently running */
+} ecma_executable_object_flags_t;
+
+/**
+ * Checks whether the executable object is waiting for resuming.
+ */
+#define ECMA_EXECUTABLE_OBJECT_IS_SUSPENDED(extra_info) \
+  (!((extra_info) & (ECMA_EXECUTABLE_OBJECT_COMPLETED | ECMA_EXECUTABLE_OBJECT_RUNNING)))
+
+/**
+ * Executable (e.g. generator, async) object flags.
+ */
+typedef enum
+{
+  ECMA_GENERATOR_NEXT, /**< generator should continue its execution */
+  ECMA_GENERATOR_RETURN, /**< generator should perform a return operation */
+  ECMA_GENERATOR_THROW, /**< generator should perform a throw operation */
+} ecma_generator_yield_mode_t;
+
+#endif /* ENABLED (JERRY_ES2015) */
+
 #if ENABLED (JERRY_ES2015_BUILTIN_DATAVIEW)
 /**
  * Description of DataView objects.

jerry-core/ecma/base/ecma-helpers-value.c

@@ -855,10 +855,10 @@ ecma_fast_copy_value (ecma_value_t value)  /**< value description */
  *
  * @return copy of the given value
  */
-ecma_value_t
+inline ecma_value_t JERRY_ATTR_ALWAYS_INLINE
 ecma_copy_value_if_not_object (ecma_value_t value) /**< value description */
 {
-  if (ecma_get_value_type_field (value) != ECMA_TYPE_OBJECT)
+  if (!ecma_is_value_object (value))
   {
     return ecma_copy_value (value);
   }
@@ -866,6 +866,30 @@ ecma_copy_value_if_not_object (ecma_value_t value) /**< value description */
   return value;
 } /* ecma_copy_value_if_not_object */
 
+/**
+ * Increase reference counter of a value if it is an object.
+ */
+inline void JERRY_ATTR_ALWAYS_INLINE
+ecma_ref_if_object (ecma_value_t value) /**< value description */
+{
+  if (ecma_is_value_object (value))
+  {
+    ecma_ref_object (ecma_get_object_from_value (value));
+  }
+} /* ecma_ref_if_object */
+
+/**
+ * Decrease reference counter of a value if it is an object.
+ */
+inline void JERRY_ATTR_ALWAYS_INLINE
+ecma_deref_if_object (ecma_value_t value) /**< value description */
+{
+  if (ecma_is_value_object (value))
+  {
+    ecma_deref_object (ecma_get_object_from_value (value));
+  }
+} /* ecma_deref_if_object */
+
 /**
  * Assign a new value to an ecma-value
  *

jerry-core/ecma/base/ecma-helpers.h

@@ -218,6 +218,8 @@ ecma_value_t JERRY_ATTR_CONST ecma_invert_boolean_value (ecma_value_t value);
 ecma_value_t ecma_copy_value (ecma_value_t value);
 ecma_value_t ecma_fast_copy_value (ecma_value_t value);
 ecma_value_t ecma_copy_value_if_not_object (ecma_value_t value);
+void ecma_ref_if_object (ecma_value_t value);
+void ecma_deref_if_object (ecma_value_t value);
 ecma_value_t ecma_update_float_number (ecma_value_t float_value, ecma_number_t new_number);
 void ecma_value_assign_value (ecma_value_t *value_p, ecma_value_t ecma_value);
 void ecma_value_assign_number (ecma_value_t *value_p, ecma_number_t ecma_number);