From b0a575b049a50a3f8ad0b0dc59c13fe996305d60 Mon Sep 17 00:00:00 2001
From: Szilagyi Adam <aszilagy@inf.u-szeged.hu>
Date: Thu, 20 Feb 2020 13:01:04 +0100
Subject: [PATCH] Use stringbuilder in vm_get_backtrace (#3566)

JerryScript-DCO-1.0-Signed-off-by: Adam Szilagyi aszilagy@inf.u-szeged.hu
---
 jerry-core/lit/lit-magic-strings.inc.h |  3 ---
 jerry-core/lit/lit-magic-strings.ini   |  1 -
 jerry-core/vm/vm-utils.c               | 16 +++++++++-------
 3 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/jerry-core/lit/lit-magic-strings.inc.h b/jerry-core/lit/lit-magic-strings.inc.h
index f46fa2622..880a0f47a 100644
--- a/jerry-core/lit/lit-magic-strings.inc.h
+++ b/jerry-core/lit/lit-magic-strings.inc.h
@@ -25,9 +25,6 @@ LIT_MAGIC_STRING_DEF (LIT_MAGIC_STRING_ASTERIX_CHAR, "*")
 || ENABLED (JERRY_ES2015_BUILTIN_TYPEDARRAY)
 LIT_MAGIC_STRING_DEF (LIT_MAGIC_STRING_COMMA_CHAR, ",")
 #endif
-#if ENABLED (JERRY_LINE_INFO)
-LIT_MAGIC_STRING_DEF (LIT_MAGIC_STRING_COLON_CHAR, ":")
-#endif
 #if ENABLED (JERRY_BUILTIN_MATH)
 LIT_MAGIC_STRING_DEF (LIT_MAGIC_STRING_E_U, "E")
 #endif
diff --git a/jerry-core/lit/lit-magic-strings.ini b/jerry-core/lit/lit-magic-strings.ini
index 304b2283e..44be66ee1 100644
--- a/jerry-core/lit/lit-magic-strings.ini
+++ b/jerry-core/lit/lit-magic-strings.ini
@@ -26,7 +26,6 @@ LIT_MAGIC_STRING__EMPTY = ""
 LIT_MAGIC_STRING_ASTERIX_CHAR = "*"
 LIT_MAGIC_STRING_SPACE_CHAR = " "
 LIT_MAGIC_STRING_COMMA_CHAR = ","
-LIT_MAGIC_STRING_COLON_CHAR = ":"
 LIT_MAGIC_STRING_E_U = "E"
 LIT_MAGIC_STRING_LEFT_SQUARE_CHAR = "["
 LIT_MAGIC_STRING_RIGHT_SQUARE_CHAR = "]"
diff --git a/jerry-core/vm/vm-utils.c b/jerry-core/vm/vm-utils.c
index 845d7b3f0..5a9884bf0 100644
--- a/jerry-core/vm/vm-utils.c
+++ b/jerry-core/vm/vm-utils.c
@@ -16,6 +16,7 @@
 #include "ecma-array-object.h"
 #include "ecma-helpers.h"
 #include "jcontext.h"
+#include "lit-char-helpers.h"
 #include "vm.h"
 
 /**
@@ -82,24 +83,25 @@ vm_get_backtrace (uint32_t max_depth) /**< maximum backtrace depth, 0 = unlimite
     }
 
     ecma_string_t *str_p = ecma_get_string_from_value (context_p->resource_name);
+    ecma_stringbuilder_t builder = ecma_stringbuilder_create ();
 
     if (ecma_string_is_empty (str_p))
     {
-      const lit_utf8_byte_t unknown_str[] = "<unknown>:";
-      str_p = ecma_new_ecma_string_from_utf8 (unknown_str, sizeof (unknown_str) - 1);
+      ecma_stringbuilder_append_raw (&builder, (const lit_utf8_byte_t *)"<unknown>:", 10);
     }
     else
     {
-      ecma_ref_ecma_string (str_p);
-      str_p = ecma_append_magic_string_to_string (str_p, LIT_MAGIC_STRING_COLON_CHAR);
+      ecma_stringbuilder_append (&builder, str_p);
+      ecma_stringbuilder_append_byte (&builder, LIT_CHAR_COLON);
     }
 
     ecma_string_t *line_str_p = ecma_new_ecma_string_from_uint32 (context_p->current_line);
-    str_p = ecma_concat_ecma_strings (str_p, line_str_p);
+    ecma_stringbuilder_append (&builder, line_str_p);
     ecma_deref_ecma_string (line_str_p);
 
-    ecma_fast_array_set_property (array_p, index, ecma_make_string_value (str_p));
-    ecma_deref_ecma_string (str_p);
+    ecma_string_t *builder_str_p = ecma_stringbuilder_finalize (&builder);
+    ecma_fast_array_set_property (array_p, index, ecma_make_string_value (builder_str_p));
+    ecma_deref_ecma_string (builder_str_p);
 
     context_p = context_p->prev_context_p;
     index++;