4 files changed, 38 insertions, 11 deletions
diff --git a/include/mrbconf.h b/include/mrbconf.h
index 3564f6ec5..0195ae96f 100644
--- a/include/mrbconf.h
+++ b/include/mrbconf.h
@@ -38,6 +38,9 @@
 /* initial size for IV khash; ignored when MRB_USE_IV_SEGLIST is set */
 //#define MRB_IVHASH_INIT_SIZE 8
 
+/* if _etext and _edata available, mruby can reduce memory used by symbols */
+//#define MRB_USE_ETEXT_EDATA
+
 /* turn off generational GC by default */
 //#define MRB_GC_TURN_OFF_GENERATIONAL
 
diff --git a/include/mruby/value.h b/include/mruby/value.h
index f85cdd644..09d00302e 100644
--- a/include/mruby/value.h
+++ b/include/mruby/value.h
@@ -211,4 +211,17 @@ mrb_undef_value(void)
   return v;
 }
 
+#ifdef MRB_USE_ETEXT_EDATA
+extern char _etext[];
+extern char _edata[];
+
+static inline mrb_bool
+mrb_ro_data_p(const char *p)
+{
+  return _etext < p && p < _edata;
+}
+#else
+# define mrb_ro_data_p(p) FALSE
+#endif
+
 #endif  /* MRUBY_VALUE_H */
diff --git a/src/string.c b/src/string.c
index c1041f4be..63c0e4573 100644
--- a/src/string.c
+++ b/src/string.c
@@ -141,10 +141,30 @@ mrb_str_resize(mrb_state *mrb, mrb_value str, mrb_int len)
 #define mrb_obj_alloc_string(mrb) ((struct RString*)mrb_obj_alloc((mrb), MRB_TT_STRING, (mrb)->string_class))
 
 static struct RString*
+str_new_static(mrb_state *mrb, const char *p, size_t len)
+{
+  struct RString *s;
+
+  if (len >= MRB_INT_MAX) {
+    mrb_raise(mrb, E_ARGUMENT_ERROR, "string size too big");
+  }
+  s = mrb_obj_alloc_string(mrb);
+  s->as.heap.len = len;
+  s->as.heap.aux.capa = 0;             /* nofree */
+  s->as.heap.ptr = (char *)p;
+  s->flags = MRB_STR_NOFREE;
+
+  return s;
+}
+
+static struct RString*
 str_new(mrb_state *mrb, const char *p, size_t len)
 {
   struct RString *s;
 
+  if (mrb_ro_data_p(p)) {
+    return str_new_static(mrb, p, len);
+  }
   s = mrb_obj_alloc_string(mrb);
   if (len < RSTRING_EMBED_LEN_MAX) {
     RSTR_SET_EMBED_FLAG(s);
@@ -282,16 +302,7 @@ mrb_str_new_cstr(mrb_state *mrb, const char *p)
 MRB_API mrb_value
 mrb_str_new_static(mrb_state *mrb, const char *p, size_t len)
 {
-  struct RString *s;
-
-  if (len >= MRB_INT_MAX) {
-    mrb_raise(mrb, E_ARGUMENT_ERROR, "string size too big");
-  }
-  s = mrb_obj_alloc_string(mrb);
-  s->as.heap.len = len;
-  s->as.heap.aux.capa = 0;             /* nofree */
-  s->as.heap.ptr = (char *)p;
-  s->flags = MRB_STR_NOFREE;
+  struct RString *s = str_new_static(mrb, p, len);
   return mrb_obj_value(s);
 }
 
diff --git a/src/symbol.c b/src/symbol.c
index 98c258503..0bcb26adf 100644
--- a/src/symbol.c
+++ b/src/symbol.c
@@ -73,7 +73,7 @@ sym_intern(mrb_state *mrb, const char *name, size_t len, mrb_bool lit)
   }
   sname = &mrb->symtbl[sym];
   sname->len = (uint16_t)len;
-  if (lit) {
+  if (lit || mrb_ro_data_p(name)) {
     sname->name = name;
     sname->lit = TRUE;
   }