Introducing ECMA_OP_TO_NUMBER_TRY_CATCH and ECMA_OP_TO_NUMBER_FINALIZE macroses.

- the ECMA_OP_TO_NUMBER_TRY_CATCH macro gets number from given value,
    converting the value to number if it's type is different,
    and catching possible conversion exceptions;

  - using the macroses instead of ecma_op_to_number to reduce allocator invocations
    in several routines with arguments that are likely to be numbers.

src/libecmaoperations/ecma-try-catch-macro.h

@@ -50,4 +50,49 @@
 #define ECMA_FINALIZE(var) } \
   ecma_free_completion_value (var)
 
+/**
+ * The macro defines try-block that tries to perform ToNumber operation on given value
+ * and checks for exceptions that might be thrown during the operation.
+ *
+ * If no exception was thrown, then code after the try-block is executed.
+ * Otherwise, throw-completion value is just copied to return_value.
+ *
+ * Note:
+ *      Each ECMA_OP_TO_NUMBER_TRY_CATCH should have it's own corresponding ECMA_OP_TO_NUMBER_FINALIZE
+ *      statement with same argument as corresponding ECMA_OP_TO_NUMBER_TRY_CATCH's first argument.
+ */
+#define ECMA_OP_TO_NUMBER_TRY_CATCH(num_var, value, return_value) \
+  JERRY_ASSERT (ecma_is_completion_value_empty (return_value)); \
+  ecma_number_t num_var = ecma_number_make_nan (); \
+  if (ecma_is_value_number (value)) \
+  { \
+    num_var = *ecma_get_number_from_value (value); \
+  } \
+  else \
+  { \
+    ECMA_TRY_CATCH (to_number_completion_value, \
+                    ecma_op_to_number (value), \
+                    return_value); \
+    \
+    num_var = *ecma_get_number_from_completion_value (to_number_completion_value); \
+    \
+    ECMA_FINALIZE (to_number_completion_value); \
+  } \
+  \
+  if (ecma_is_completion_value_empty (return_value)) \
+  {
+
+/**
+ * The macro marks end of code block that is defined by corresponding ECMA_OP_TO_NUMBER_TRY_CATCH.
+ *
+ * Note:
+ *      Each ECMA_OP_TO_NUMBER_TRY_CATCH should be followed by ECMA_OP_TO_NUMBER_FINALIZE
+ *      with same argument as corresponding ECMA_OP_TO_NUMBER_TRY_CATCH's first argument.
+ */
+#define ECMA_OP_TO_NUMBER_FINALIZE(num_var) } \
+  else \
+  { \
+    JERRY_ASSERT (ecma_number_is_nan (num_var)); \
+  }
+
 #endif /* !ECMA_TRY_CATCH_MACRO_H */