Rework VM dispatch

Overview:
- `VM_OC_*` opcodes are removed, now the dispatch is based on the `CBC`/`CBC_EXT` opcode
- The common argument decoding is removed, now each opcode resolves it's arguments individually using `VM_DECODE_{EXT}_...` macros. Whenever an argument is decoded the dispatcher continues with the same opcode increased by `VM_OPCODE_DECODED_ARG`.
- E.g.: A opcode with 2 literal arguments dispatches as the following:
  - step_1: `case opcode: goto resolve_first_literal`, opcode increment by `VM_OPCODE_DECODED_ARG`, dispatch again (Hidden by macro)
  - step_2: `case VM_OPCODE_ONE_LITERAL(opcode): goto resolve_second_literal`, opcode increment by `VM_OPCODE_DECODED_ARG`, dispatch again (Hidden by macro)
  - step_3: `case VM_OPCODE_TWO_LITERALS (opcode):` Opcode handler implementation goes here.
  - The opcode handler implementation goes as the following:
```c
  case VM_OPCODE_TWO_LITERALS (opcode):
  {
    VM_DECODE_LITERAL_LITERAL (opcode);

   /* use left and right value as before */
  }
```
- The put result block is optimized, each assignment knows whether an ident or property reference should be resolved
- `free_left_value` and `free_both_values` labels are removed, due to the extra long jumps they caused to execute 1 or 2 simple calls.

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

Author: Robert Fancsik

docs/05.PORT-API.md

@@ -26,8 +26,7 @@ typedef enum
 {
   JERRY_FATAL_OUT_OF_MEMORY = 10,
   JERRY_FATAL_REF_COUNT_LIMIT = 12,
-  JERRY_FATAL_DISABLED_BYTE_CODE = 13,
-  JERRY_FATAL_UNTERMINATED_GC_LOOPS = 14,
+  JERRY_FATAL_UNTERMINATED_GC_LOOPS = 13,
   JERRY_FATAL_FAILED_ASSERTION = 120
 } jerry_fatal_code_t;
 ```

jerry-core/api/jerry-snapshot.c

@@ -34,46 +34,43 @@
 #if JERRY_SNAPSHOT_SAVE || JERRY_SNAPSHOT_EXEC
 
 /**
- * Get snapshot configuration flags.
+ * Get snapshot feature configuration flags.
  *
- * @return configuration flags
+ * @return feature configuration flags
  */
-static inline uint32_t JERRY_ATTR_ALWAYS_INLINE
-snapshot_get_global_flags (bool has_regex, /**< regex literal is present */
-                           bool has_class) /**< class literal is present */
+static inline jerry_snapshot_feature_flags_t
+snapshot_get_feature_flags (void)
 {
-  JERRY_UNUSED (has_regex);
-  JERRY_UNUSED (has_class);
-
-  uint32_t flags = 0;
+  jerry_snapshot_feature_flags_t flags = JERRY_SNAPSHOT_FEATURE_NONE;
 
 #if JERRY_BUILTIN_REGEXP
-  flags |= (has_regex ? JERRY_SNAPSHOT_HAS_REGEX_LITERAL : 0);
+  flags |= JERRY_SNAPSHOT_FEATURE_REGEXP;
 #endif /* JERRY_BUILTIN_REGEXP */
+#if JERRY_MODULE_SYSTEM
+  flags |= JERRY_SNAPSHOT_FEATURE_MODULE;
+#endif /* JERRY_MODULE_SYSTEM */
+#if JERRY_DEBUGGER
+  flags |= JERRY_SNAPSHOT_FEATURE_DEBUGGER;
+#endif /* JERRY_DEBUGGER */
 #if JERRY_ESNEXT
-  flags |= (has_class ? JERRY_SNAPSHOT_HAS_CLASS_LITERAL : 0);
+  flags |= JERRY_SNAPSHOT_FEATURE_ESNEXT;
 #endif /* JERRY_ESNEXT */
 
   return flags;
-} /* snapshot_get_global_flags */
+} /* snapshot_get_feature_flags */
 
 /**
- * Checks whether the global_flags argument matches to the current feature set.
+ * Validate snapshot header
  *
- * @return true if global_flags accepted, false otherwise
+ * @return true - if the header is valid
+ *         false - otherwise
  */
-static inline bool JERRY_ATTR_ALWAYS_INLINE
-snapshot_check_global_flags (uint32_t global_flags) /**< global flags */
+static bool
+snapshot_validate_header (const jerry_snapshot_header_t *header_p)
 {
-#if JERRY_BUILTIN_REGEXP
-  global_flags &= (uint32_t) ~JERRY_SNAPSHOT_HAS_REGEX_LITERAL;
-#endif /* JERRY_BUILTIN_REGEXP */
-#if JERRY_ESNEXT
-  global_flags &= (uint32_t) ~JERRY_SNAPSHOT_HAS_CLASS_LITERAL;
-#endif /* JERRY_ESNEXT */
-
-  return global_flags == snapshot_get_global_flags (false, false);
-} /* snapshot_check_global_flags */
+  return (header_p->magic == JERRY_SNAPSHOT_MAGIC && header_p->version == JERRY_SNAPSHOT_VERSION
+          && (header_p->feature_flags & snapshot_get_feature_flags ()) == header_p->feature_flags);
+} /* snapshot_validate_header */
 
 #endif /* JERRY_SNAPSHOT_SAVE || JERRY_SNAPSHOT_EXEC */
 
@@ -86,8 +83,6 @@ typedef struct
 {
   size_t snapshot_buffer_write_offset;
   ecma_value_t snapshot_error;
-  bool regex_found;
-  bool class_found;
 } snapshot_globals_t;
 
 /** \addtogroup jerrysnapshot Jerry snapshot operations
@@ -171,11 +166,6 @@ snapshot_add_compiled_code (const ecma_compiled_code_t *compiled_code_p, /**< co
       jerry_throw_sz (JERRY_ERROR_RANGE, ecma_get_error_msg (ECMA_ERR_TAGGED_TEMPLATE_LITERALS));
     return 0;
   }
-
-  if (CBC_FUNCTION_GET_TYPE (compiled_code_p->status_flags) == CBC_FUNCTION_CONSTRUCTOR)
-  {
-    globals_p->class_found = true;
-  }
 #endif /* JERRY_ESNEXT */
 
 #if JERRY_BUILTIN_REGEXP
@@ -216,7 +206,6 @@ snapshot_add_compiled_code (const ecma_compiled_code_t *compiled_code_p, /**< co
       return 0;
     }
 
-    globals_p->regex_found = true;
     globals_p->snapshot_buffer_write_offset = JERRY_ALIGNUP (globals_p->snapshot_buffer_write_offset, JMEM_ALIGNMENT);
 
     /* Regexp character size is stored in refs. */
@@ -788,8 +777,6 @@ jerry_generate_snapshot (jerry_value_t compiled_code, /**< parsed script or func
 
   globals.snapshot_buffer_write_offset = aligned_header_size;
   globals.snapshot_error = ECMA_VALUE_EMPTY;
-  globals.regex_found = false;
-  globals.class_found = false;
 
   if (generate_snapshot_opts & JERRY_SNAPSHOT_SAVE_STATIC)
   {
@@ -808,7 +795,7 @@ jerry_generate_snapshot (jerry_value_t compiled_code, /**< parsed script or func
   jerry_snapshot_header_t header;
   header.magic = JERRY_SNAPSHOT_MAGIC;
   header.version = JERRY_SNAPSHOT_VERSION;
-  header.global_flags = snapshot_get_global_flags (globals.regex_found, globals.class_found);
+  header.feature_flags = (uint32_t) snapshot_get_feature_flags ();
   header.lit_table_offset = (uint32_t) globals.snapshot_buffer_write_offset;
   header.number_of_funcs = 1;
   header.func_offsets[0] = aligned_header_size;
@@ -897,8 +884,7 @@ jerry_exec_snapshot (const uint32_t *snapshot_p, /**< snapshot */
 
   const jerry_snapshot_header_t *header_p = (const jerry_snapshot_header_t *) snapshot_data_p;
 
-  if (header_p->magic != JERRY_SNAPSHOT_MAGIC || header_p->version != JERRY_SNAPSHOT_VERSION
-      || !snapshot_check_global_flags (header_p->global_flags))
+  if (!snapshot_validate_header (header_p))
   {
     return jerry_throw_sz (JERRY_ERROR_TYPE, ecma_get_error_msg (ECMA_ERR_INVALID_SNAPSHOT_VERSION_OR_FEATURES));
   }
@@ -1219,7 +1205,6 @@ jerry_merge_snapshots (const uint32_t **inp_buffers_p, /**< array of (pointers t
 {
 #if JERRY_SNAPSHOT_SAVE
   uint32_t number_of_funcs = 0;
-  uint32_t merged_global_flags = 0;
   size_t functions_size = sizeof (jerry_snapshot_header_t);
 
   if (number_of_snapshots < 2)
@@ -1241,16 +1226,13 @@ jerry_merge_snapshots (const uint32_t **inp_buffers_p, /**< array of (pointers t
 
     const jerry_snapshot_header_t *header_p = (const jerry_snapshot_header_t *) inp_buffers_p[i];
 
-    if (header_p->magic != JERRY_SNAPSHOT_MAGIC || header_p->version != JERRY_SNAPSHOT_VERSION
-        || !snapshot_check_global_flags (header_p->global_flags))
+    if (!snapshot_validate_header (header_p))
     {
       *error_p = "invalid snapshot version or unsupported features present";
       ecma_collection_destroy (lit_pool_p);
       return 0;
     }
 
-    merged_global_flags |= header_p->global_flags;
-
     uint32_t start_offset = header_p->func_offsets[0];
     const uint8_t *data_p = (const uint8_t *) inp_buffers_p[i];
     const uint8_t *literal_base_p = data_p + header_p->lit_table_offset;
@@ -1278,7 +1260,7 @@ jerry_merge_snapshots (const uint32_t **inp_buffers_p, /**< array of (pointers t
 
   header_p->magic = JERRY_SNAPSHOT_MAGIC;
   header_p->version = JERRY_SNAPSHOT_VERSION;
-  header_p->global_flags = merged_global_flags;
+  header_p->feature_flags = snapshot_get_feature_flags ();
   header_p->lit_table_offset = (uint32_t) functions_size;
   header_p->number_of_funcs = number_of_funcs;
 
@@ -1555,8 +1537,7 @@ jerry_get_literals_from_snapshot (const uint32_t *snapshot_p, /**< input snapsho
   const uint8_t *snapshot_data_p = (uint8_t *) snapshot_p;
   const jerry_snapshot_header_t *header_p = (const jerry_snapshot_header_t *) snapshot_data_p;
 
-  if (snapshot_size <= sizeof (jerry_snapshot_header_t) || header_p->magic != JERRY_SNAPSHOT_MAGIC
-      || header_p->version != JERRY_SNAPSHOT_VERSION || !snapshot_check_global_flags (header_p->global_flags))
+  if (snapshot_size <= sizeof (jerry_snapshot_header_t) || !snapshot_validate_header (header_p))
   {
     /* Invalid snapshot format */
     return 0;

jerry-core/api/jerry-snapshot.h

@@ -27,7 +27,7 @@ typedef struct
    * uint32_t alignment. Otherwise some bytes after the header are wasted. */
   uint32_t magic; /**< four byte magic number */
   uint32_t version; /**< version number */
-  uint32_t global_flags; /**< global configuration and feature flags */
+  uint32_t feature_flags; /**< combination of jerry_snapshot_global_flags_t */
   uint32_t lit_table_offset; /**< byte offset of the literal table */
   uint32_t number_of_funcs; /**< number of primary ECMAScript functions */
   uint32_t func_offsets[1]; /**< function offsets (lowest bit: global(0) or eval(1) context) */
@@ -39,15 +39,15 @@ typedef struct
 #define JERRY_SNAPSHOT_MAGIC (0x5952524Au)
 
 /**
- * Snapshot configuration flags.
+ * Feature flags for snapshot execution.
  */
 typedef enum
 {
-  /* 8 bits are reserved for dynamic features */
-  JERRY_SNAPSHOT_HAS_REGEX_LITERAL = (1u << 0), /**< byte code has regex literal */
-  JERRY_SNAPSHOT_HAS_CLASS_LITERAL = (1u << 1), /**< byte code has class literal */
-  /* 24 bits are reserved for compile time features */
-  JERRY_SNAPSHOT_FOUR_BYTE_CPOINTER = (1u << 8) /**< deprecated, an unused placeholder now */
-} jerry_snapshot_global_flags_t;
+  JERRY_SNAPSHOT_FEATURE_NONE = 0,
+  JERRY_SNAPSHOT_FEATURE_REGEXP = (1u << 0), /**< feature flag for JERRY_BUILTIN_REGEXP */
+  JERRY_SNAPSHOT_FEATURE_MODULE = (1u << 1), /**< feature flag for JERRY_MODULE_SYSTEM */
+  JERRY_SNAPSHOT_FEATURE_DEBUGGER = (1u << 2), /**< feature flag for JERRY_DEBUGGER */
+  JERRY_SNAPSHOT_FEATURE_ESNEXT = (1u << 3), /**< feature flag for JERRY_ESNEXT */
+} jerry_snapshot_feature_flags_t;
 
 #endif /* !JERRY_SNAPSHOT_H */

jerry-core/include/jerryscript-port.h

@@ -44,8 +44,7 @@ typedef enum
 {
   JERRY_FATAL_OUT_OF_MEMORY = 10, /**< Out of memory */
   JERRY_FATAL_REF_COUNT_LIMIT = 12, /**< Reference count limit reached */
-  JERRY_FATAL_DISABLED_BYTE_CODE = 13, /**< Executed disabled instruction */
-  JERRY_FATAL_UNTERMINATED_GC_LOOPS = 14, /**< Garbage collection loop limit reached */
+  JERRY_FATAL_UNTERMINATED_GC_LOOPS = 13, /**< Garbage collection loop limit reached */
   JERRY_FATAL_FAILED_ASSERTION = 120 /**< Assertion failed */
 } jerry_fatal_code_t;
 

jerry-core/jrt/jrt-fatals.c

@@ -47,11 +47,6 @@ jerry_fatal (jerry_fatal_code_t code) /**< status code */
       JERRY_ERROR_MSG ("Error: JERRY_FATAL_UNTERMINATED_GC_LOOPS\n");
       break;
     }
-    case JERRY_FATAL_DISABLED_BYTE_CODE:
-    {
-      JERRY_ERROR_MSG ("Error: JERRY_FATAL_DISABLED_BYTE_CODE\n");
-      break;
-    }
     case JERRY_FATAL_FAILED_ASSERTION:
     {
       JERRY_ERROR_MSG ("Error: JERRY_FATAL_FAILED_ASSERTION\n");

jerry-core/parser/js/byte-code.c

@@ -45,7 +45,7 @@ JERRY_STATIC_ASSERT (CBC_EXT_END == 167, number_of_cbc_ext_opcodes_changed);
 /**
  * Compact bytecode definition
  */
-#define CBC_OPCODE(arg1, arg2, arg3, arg4) ((arg2) | (((arg3) + CBC_STACK_ADJUST_BASE) << CBC_STACK_ADJUST_SHIFT)),
+#define CBC_OPCODE(arg1, arg2, arg3) ((arg2) | (((arg3) + CBC_STACK_ADJUST_BASE) << CBC_STACK_ADJUST_SHIFT)),
 
 /**
  * Flags of the opcodes.
@@ -63,7 +63,7 @@ const uint8_t cbc_ext_flags[] = { CBC_EXT_OPCODE_LIST };
 
 #if JERRY_PARSER_DUMP_BYTE_CODE
 
-#define CBC_OPCODE(arg1, arg2, arg3, arg4) #arg1,
+#define CBC_OPCODE(arg1, arg2, arg3) #arg1,
 
 /**
  * Names of the opcodes.