Reduce register pressure by reusing registers, allocated for argument preparation instruction sequence.

JerryScript-DCO-1.0-Signed-off-by: Ruben Ayrapetyan r.ayrapetyan@samsung.com

Author: Ruben Ayrapetyan

jerry-core/parser/js/opcodes-dumper.cpp

@@ -755,6 +755,41 @@ dumper_finish_scope (void)
   STACK_DROP (temp_names, 1);
 }
 
+/**
+ * Handle start of argument preparation instruction sequence generation
+ *
+ * Note:
+ *      Values of registers, allocated for the code sequence, are not used outside of the sequence,
+ *      so they can be reused, reducing register pressure.
+ *
+ *      To reuse the registers, counter of register allocator is saved, and restored then,
+ *      after finishing generation of the code sequence, using dumper_finish_varg_code_sequence.
+ *
+ * FIXME:
+ *       Implement general register allocation mechanism
+ *
+ * See also:
+ *          dumper_finish_varg_code_sequence
+ */
+void
+dumper_start_varg_code_sequence (void)
+{
+  STACK_PUSH (temp_names, temp_name);
+} /* dumper_start_varg_code_sequence */
+
+/**
+ * Handle finish of argument preparation instruction sequence generation
+ *
+ * See also:
+ *          dumper_start_varg_code_sequence
+ */
+void
+dumper_finish_varg_code_sequence (void)
+{
+  temp_name = STACK_TOP (temp_names);
+  STACK_DROP (temp_names, 1);
+} /* dumper_finish_varg_code_sequence */
+
 /**
  * Check that byte-code operand refers to 'eval' string
  *

jerry-core/parser/js/opcodes-dumper.h

@@ -58,6 +58,8 @@ void dumper_free (void);
 void dumper_new_statement (void);
 void dumper_new_scope (void);
 void dumper_finish_scope (void);
+void dumper_start_varg_code_sequence (void);
+void dumper_finish_varg_code_sequence (void);
 
 extern bool dumper_is_eval_literal (operand);
 

jerry-core/parser/js/parser.cpp

@@ -521,6 +521,8 @@ parse_argument_list (varg_list_type vlt, operand obj, uint8_t *args_count, opera
   skip_newlines ();
   while (!token_is (close_tt))
   {
+    dumper_start_varg_code_sequence ();
+
     operand op;
 
     if (vlt == VARG_FUNC_DECL
@@ -572,6 +574,8 @@ parse_argument_list (varg_list_type vlt, operand obj, uint8_t *args_count, opera
     }
 
     args_num++;
+
+    dumper_finish_varg_code_sequence ();
   }
 
   if (args_count != NULL)