Reduce try context stack consumption to 1 from 2. (#3898)

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

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

@@ -189,7 +189,9 @@
 /* Stack consumption of opcodes with context. */
 
 /* PARSER_TRY_CONTEXT_STACK_ALLOCATION must be <= 3 */
-#define PARSER_TRY_CONTEXT_STACK_ALLOCATION 2
+#define PARSER_TRY_CONTEXT_STACK_ALLOCATION 1
+/* PARSER_FINALLY_CONTEXT_STACK_ALLOCATION must be <= 3 */
+#define PARSER_FINALLY_CONTEXT_STACK_ALLOCATION 2
 /* PARSER_FOR_IN_CONTEXT_STACK_ALLOCATION must be <= 4 */
 #define PARSER_FOR_IN_CONTEXT_STACK_ALLOCATION 4
 /* PARSER_FOR_OF_CONTEXT_STACK_ALLOCATION must be <= 3 */
@@ -199,6 +201,12 @@
 /* PARSER_BLOCK_CONTEXT_STACK_ALLOCATION must be <= 3 */
 #define PARSER_BLOCK_CONTEXT_STACK_ALLOCATION 1
 
+/**
+ * Extra stack consumption for finally context.
+ */
+#define PARSER_FINALLY_CONTEXT_EXTRA_STACK_ALLOCATION \
+  (PARSER_FINALLY_CONTEXT_STACK_ALLOCATION - PARSER_TRY_CONTEXT_STACK_ALLOCATION)
+
 /**
  * Opcode definitions.
  */
@@ -552,7 +560,7 @@
                       VM_OC_CATCH) \
   CBC_OPCODE (CBC_EXT_RESOLVE_BASE, CBC_NO_FLAG, 0, \
               VM_OC_RESOLVE_BASE_FOR_CALL) \
-  CBC_FORWARD_BRANCH (CBC_EXT_FINALLY, 0, \
+  CBC_FORWARD_BRANCH (CBC_EXT_FINALLY, PARSER_FINALLY_CONTEXT_EXTRA_STACK_ALLOCATION, \
                       VM_OC_FINALLY) \
   CBC_OPCODE (CBC_EXT_INITIALIZER_PUSH_PROP, CBC_NO_FLAG, 0, \
               VM_OC_INITIALIZER_PUSH_PROP | VM_OC_GET_STACK) \

jerry-core/parser/js/js-parser-statm.c

@@ -1886,9 +1886,9 @@ parser_parse_try_statement_end (parser_context_t *context_p) /**< context */
   if (try_statement.type == parser_finally_block)
   {
     parser_flush_cbc (context_p);
-    PARSER_MINUS_EQUAL_U16 (context_p->stack_depth, PARSER_TRY_CONTEXT_STACK_ALLOCATION);
+    PARSER_MINUS_EQUAL_U16 (context_p->stack_depth, PARSER_FINALLY_CONTEXT_STACK_ALLOCATION);
 #ifndef JERRY_NDEBUG
-    PARSER_MINUS_EQUAL_U16 (context_p->context_stack_depth, PARSER_TRY_CONTEXT_STACK_ALLOCATION);
+    PARSER_MINUS_EQUAL_U16 (context_p->context_stack_depth, PARSER_FINALLY_CONTEXT_STACK_ALLOCATION);
 #endif /* !JERRY_NDEBUG */
 
     parser_emit_cbc (context_p, CBC_CONTEXT_END);
@@ -1919,11 +1919,15 @@ parser_parse_try_statement_end (parser_context_t *context_p) /**< context */
         try_statement.type = parser_finally_block;
       }
     }
-    else if (try_statement.type == parser_try_block
+    else
-             && context_p->token.type != LEXER_KEYW_CATCH
-             && context_p->token.type != LEXER_KEYW_FINALLY)
     {
-      parser_raise_error (context_p, PARSER_ERR_CATCH_FINALLY_EXPECTED);
+      JERRY_ASSERT (try_statement.type == parser_try_block);
+
+      if (context_p->token.type != LEXER_KEYW_CATCH
+          && context_p->token.type != LEXER_KEYW_FINALLY)
+      {
+        parser_raise_error (context_p, PARSER_ERR_CATCH_FINALLY_EXPECTED);
+      }
     }
   }
 
@@ -2029,6 +2033,10 @@ parser_parse_try_statement_end (parser_context_t *context_p) /**< context */
       parser_raise_error (context_p, PARSER_ERR_LEFT_BRACE_EXPECTED);
     }
 
+#ifndef JERRY_NDEBUG
+    PARSER_PLUS_EQUAL_U16 (context_p->context_stack_depth, PARSER_FINALLY_CONTEXT_EXTRA_STACK_ALLOCATION);
+#endif /* !JERRY_NDEBUG */
+
     try_statement.type = parser_finally_block;
     parser_emit_cbc_ext_forward_branch (context_p,
                                         CBC_EXT_FINALLY,

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

@@ -964,6 +964,11 @@ parser_post_processing (parser_context_t *context_p) /**< context */
     PARSER_MINUS_EQUAL_U16 (context_p->context_stack_depth, PARSER_TRY_CONTEXT_STACK_ALLOCATION);
 #endif /* !JERRY_NDEBUG */
 
+    if (context_p->stack_limit < PARSER_FINALLY_CONTEXT_STACK_ALLOCATION)
+    {
+      context_p->stack_limit = PARSER_FINALLY_CONTEXT_STACK_ALLOCATION;
+    }
+
     parser_branch_t branch;
 
     parser_stack_pop (context_p, &branch, sizeof (parser_branch_t));

jerry-core/vm/vm-stack.c

@@ -30,6 +30,9 @@
 JERRY_STATIC_ASSERT (PARSER_WITH_CONTEXT_STACK_ALLOCATION == PARSER_BLOCK_CONTEXT_STACK_ALLOCATION,
                      parser_with_context_stack_allocation_must_be_equal_to_parser_block_context_stack_allocation);
 
+JERRY_STATIC_ASSERT (PARSER_WITH_CONTEXT_STACK_ALLOCATION == PARSER_TRY_CONTEXT_STACK_ALLOCATION,
+                     parser_with_context_stack_allocation_must_be_equal_to_parser_block_context_stack_allocation);
+
 /**
  * Abort (finalize) the current stack context, and remove it.
  *
@@ -58,13 +61,13 @@ vm_stack_context_abort (vm_frame_ctx_t *frame_ctx_p, /**< frame context */
       /* FALLTHRU */
     }
     case VM_CONTEXT_FINALLY_JUMP:
-    case VM_CONTEXT_TRY:
-    case VM_CONTEXT_CATCH:
     {
-      VM_MINUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_TRY_CONTEXT_STACK_ALLOCATION);
+      VM_MINUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_FINALLY_CONTEXT_STACK_ALLOCATION);
-      vm_stack_top_p -= PARSER_TRY_CONTEXT_STACK_ALLOCATION;
+      vm_stack_top_p -= PARSER_FINALLY_CONTEXT_STACK_ALLOCATION;
       break;
     }
+    case VM_CONTEXT_TRY:
+    case VM_CONTEXT_CATCH:
 #if ENABLED (JERRY_ESNEXT)
     case VM_CONTEXT_BLOCK:
 #endif /* ENABLED (JERRY_ESNEXT) */
@@ -243,6 +246,8 @@ vm_stack_find_finally (vm_frame_ctx_t *frame_ctx_p, /**< frame context */
       }
       else
       {
+        JERRY_ASSERT (context_type == VM_CONTEXT_CATCH);
+
 #if !ENABLED (JERRY_ESNEXT)
         if (vm_stack_top_p[-1] & VM_CONTEXT_HAS_LEX_ENV)
         {
@@ -263,6 +268,9 @@ vm_stack_find_finally (vm_frame_ctx_t *frame_ctx_p, /**< frame context */
 
       JERRY_ASSERT (byte_code_p[0] == CBC_EXT_OPCODE);
 
+      VM_PLUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_FINALLY_CONTEXT_EXTRA_STACK_ALLOCATION);
+      vm_stack_top_p += PARSER_FINALLY_CONTEXT_EXTRA_STACK_ALLOCATION;
+
 #if ENABLED (JERRY_ESNEXT)
       if (JERRY_UNLIKELY (byte_code_p[1] == CBC_EXT_ASYNC_EXIT))
       {
@@ -316,14 +324,14 @@ vm_get_context_value_offsets (ecma_value_t *context_item_p) /**< any item of a c
     case VM_CONTEXT_FINALLY_THROW:
     case VM_CONTEXT_FINALLY_RETURN:
     {
-      return (2 << (VM_CONTEXT_OFFSET_SHIFT)) | PARSER_TRY_CONTEXT_STACK_ALLOCATION;
+      return (2 << (VM_CONTEXT_OFFSET_SHIFT)) | PARSER_FINALLY_CONTEXT_STACK_ALLOCATION;
     }
     case VM_CONTEXT_FINALLY_JUMP:
+    {
+      return PARSER_FINALLY_CONTEXT_STACK_ALLOCATION;
+    }
     case VM_CONTEXT_TRY:
     case VM_CONTEXT_CATCH:
-    {
-      return PARSER_TRY_CONTEXT_STACK_ALLOCATION;
-    }
     case VM_CONTEXT_BLOCK:
     case VM_CONTEXT_WITH:
     {

jerry-core/vm/vm.c

@@ -2255,7 +2255,6 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
         }
         case VM_OC_ASYNC_EXIT:
         {
-          JERRY_ASSERT (frame_ctx_p->context_depth == PARSER_TRY_CONTEXT_STACK_ALLOCATION);
           JERRY_ASSERT (VM_GET_REGISTERS (frame_ctx_p) + register_end + frame_ctx_p->context_depth == stack_top_p);
 
           result = frame_ctx_p->block_result;
@@ -2271,22 +2270,26 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
             JERRY_CONTEXT (current_new_target) = old_new_target_p;
           }
 
-          left_value = stack_top_p[-2];
+          vm_stack_context_type_t context_type = VM_GET_CONTEXT_TYPE (stack_top_p[-1]);
 
-          if (VM_GET_CONTEXT_TYPE (stack_top_p[-1]) == VM_CONTEXT_FINALLY_THROW)
+          if (context_type == VM_CONTEXT_TRY)
+          {
+            JERRY_ASSERT (frame_ctx_p->context_depth == PARSER_TRY_CONTEXT_STACK_ALLOCATION);
+            left_value = ECMA_VALUE_UNDEFINED;
+          }
+          else
+          {
+            JERRY_ASSERT (frame_ctx_p->context_depth == PARSER_FINALLY_CONTEXT_STACK_ALLOCATION);
+            left_value = stack_top_p[-2];
+          }
+
+          if (context_type == VM_CONTEXT_FINALLY_THROW)
           {
             ecma_reject_promise (result, left_value);
           }
           else
           {
-            JERRY_ASSERT (VM_GET_CONTEXT_TYPE (stack_top_p[-1]) == VM_CONTEXT_TRY
+            JERRY_ASSERT (context_type == VM_CONTEXT_TRY || context_type == VM_CONTEXT_FINALLY_RETURN);
-                          || VM_GET_CONTEXT_TYPE (stack_top_p[-1]) == VM_CONTEXT_FINALLY_RETURN);
-
-            if (VM_GET_CONTEXT_TYPE (stack_top_p[-1]) == VM_CONTEXT_TRY)
-            {
-              left_value = ECMA_VALUE_UNDEFINED;
-            }
-
             ecma_fulfill_promise (result, left_value);
           }
 
@@ -3835,10 +3838,11 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
             JERRY_ASSERT (lex_env_p->u2.outer_reference_cp != JMEM_CP_NULL);
             frame_ctx_p->lex_env_p = ECMA_GET_NON_NULL_POINTER (ecma_object_t, lex_env_p->u2.outer_reference_cp);
             ecma_deref_object (lex_env_p);
-
-            stack_top_p[-1] &= (ecma_value_t) ~VM_CONTEXT_HAS_LEX_ENV;
           }
 
+          VM_PLUS_EQUAL_U16 (frame_ctx_p->context_depth, PARSER_FINALLY_CONTEXT_EXTRA_STACK_ALLOCATION);
+          stack_top_p += PARSER_FINALLY_CONTEXT_EXTRA_STACK_ALLOCATION;
+
           stack_top_p[-1] = VM_CREATE_CONTEXT (VM_CONTEXT_FINALLY_JUMP, branch_offset);
           stack_top_p[-2] = (ecma_value_t) branch_offset;
           continue;
@@ -3869,8 +3873,8 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
 #endif /* ENABLED (JERRY_ESNEXT) */
 
           VM_MINUS_EQUAL_U16 (frame_ctx_p->context_depth,
-                              PARSER_TRY_CONTEXT_STACK_ALLOCATION);
+                              PARSER_FINALLY_CONTEXT_STACK_ALLOCATION);
-          stack_top_p -= PARSER_TRY_CONTEXT_STACK_ALLOCATION;
+          stack_top_p -= PARSER_FINALLY_CONTEXT_STACK_ALLOCATION;
 
           if (context_type == VM_CONTEXT_FINALLY_RETURN)
           {