1 files changed, 87 insertions, 8 deletions

diff --git a/internal/string.h b/internal/string.h
index 8c481f979e..9212ce8986 100644
--- a/internal/string.h
+++ b/internal/string.h
@@ -14,15 +14,57 @@
 #include "ruby/internal/stdbool.h"     /* for bool */
 #include "ruby/encoding.h"      /* for rb_encoding */
 #include "ruby/ruby.h"          /* for VALUE */
+#include "encindex.h"
 
-#define STR_NOEMBED      FL_USER1
-#define STR_SHARED       FL_USER2 /* = ELTS_SHARED */
+#define STR_SHARED                  FL_USER0 /* = ELTS_SHARED */
+#define STR_NOEMBED                 FL_USER1
+#define STR_CHILLED                 (FL_USER2 | FL_USER3)
+#define STR_CHILLED_LITERAL         FL_USER2
+#define STR_CHILLED_SYMBOL_TO_S     FL_USER3
+
+enum ruby_rstring_private_flags {
+    RSTRING_CHILLED = STR_CHILLED,
+};
 
 #ifdef rb_fstring_cstr
 # undef rb_fstring_cstr
 #endif
 
+static inline bool
+rb_str_encindex_fastpath(int encindex)
+{
+    // The overwhelming majority of strings are in one of these 3 encodings,
+    // which are all either ASCII or perfect ASCII supersets.
+    // Hence you can use fast, single byte algorithms on them, such as `memchr` etc,
+    // without all the overhead of fetching the rb_encoding and using functions such as
+    // rb_enc_mbminlen etc.
+    // Many other encodings could qualify, but they are expected to be rare occurences,
+    // so it's better to keep that list small.
+    switch (encindex) {
+      case ENCINDEX_ASCII_8BIT:
+      case ENCINDEX_UTF_8:
+      case ENCINDEX_US_ASCII:
+        return true;
+      default:
+        return false;
+    }
+}
+
+static inline bool
+rb_str_enc_fastpath(VALUE str)
+{
+    return rb_str_encindex_fastpath(ENCODING_GET_INLINED(str));
+}
+
+static inline rb_encoding *
+rb_str_enc_get(VALUE str)
+{
+    RUBY_ASSERT(RB_TYPE_P(str, T_STRING));
+    return rb_enc_from_index(ENCODING_GET(str));
+}
+
 /* string.c */
+VALUE rb_str_dup_m(VALUE str);
 VALUE rb_fstring(VALUE);
 VALUE rb_fstring_cstr(const char *str);
 VALUE rb_fstring_enc_new(const char *ptr, long len, rb_encoding *enc);
@@ -45,6 +87,21 @@ void rb_str_make_independent(VALUE str);
 int rb_enc_str_coderange_scan(VALUE str, rb_encoding *enc);
 int rb_ascii8bit_appendable_encoding_index(rb_encoding *enc, unsigned int code);
 VALUE rb_str_include(VALUE str, VALUE arg);
+VALUE rb_str_byte_substr(VALUE str, VALUE beg, VALUE len);
+VALUE rb_str_substr_two_fixnums(VALUE str, VALUE beg, VALUE len, int empty);
+VALUE rb_str_tmp_frozen_no_embed_acquire(VALUE str);
+void rb_str_make_embedded(VALUE);
+VALUE rb_str_upto_each(VALUE, VALUE, int, int (*each)(VALUE, VALUE), VALUE);
+size_t rb_str_size_as_embedded(VALUE);
+bool rb_str_reembeddable_p(VALUE);
+VALUE rb_str_upto_endless_each(VALUE, int (*each)(VALUE, VALUE), VALUE);
+VALUE rb_str_with_debug_created_info(VALUE, VALUE, int);
+VALUE rb_str_frozen_bare_string(VALUE);
+const char *rb_str_null_check(VALUE);
+
+/* error.c */
+void rb_warn_unchilled_literal(VALUE str);
+void rb_warn_unchilled_symbol_to_s(VALUE str);
 
 static inline bool STR_EMBED_P(VALUE str);
 static inline bool STR_SHARED_P(VALUE str);
@@ -59,23 +116,22 @@ RUBY_SYMBOL_EXPORT_BEGIN
 VALUE rb_str_tmp_frozen_acquire(VALUE str);
 void rb_str_tmp_frozen_release(VALUE str, VALUE tmp);
 VALUE rb_setup_fake_str(struct RString *fake_str, const char *name, long len, rb_encoding *enc);
-VALUE rb_str_upto_each(VALUE, VALUE, int, int (*each)(VALUE, VALUE), VALUE);
-VALUE rb_str_upto_endless_each(VALUE, int (*each)(VALUE, VALUE), VALUE);
-void rb_str_make_embedded(VALUE);
-size_t rb_str_size_as_embedded(VALUE);
-bool rb_str_reembeddable_p(VALUE);
 RUBY_SYMBOL_EXPORT_END
 
 VALUE rb_fstring_new(const char *ptr, long len);
+void rb_gc_free_fstring(VALUE obj);
+bool rb_obj_is_fstring_table(VALUE obj);
+void Init_fstring_table();
 VALUE rb_obj_as_string_result(VALUE str, VALUE obj);
 VALUE rb_str_opt_plus(VALUE x, VALUE y);
 VALUE rb_str_concat_literals(size_t num, const VALUE *strary);
 VALUE rb_str_eql(VALUE str1, VALUE str2);
 VALUE rb_id_quote_unprintable(ID);
 VALUE rb_sym_proc_call(ID mid, int argc, const VALUE *argv, int kw_splat, VALUE passed_proc);
+VALUE rb_enc_literal_str(const char *ptr, long len, rb_encoding *enc);
 
 struct rb_execution_context_struct;
-VALUE rb_ec_str_resurrect(struct rb_execution_context_struct *ec, VALUE str);
+VALUE rb_ec_str_resurrect(struct rb_execution_context_struct *ec, VALUE str, bool chilled);
 
 #define rb_fstring_lit(str) rb_fstring_new((str), rb_strlen_lit(str))
 #define rb_fstring_literal(str) rb_fstring_lit(str)
@@ -107,6 +163,29 @@ STR_SHARED_P(VALUE str)
 }
 
 static inline bool
+CHILLED_STRING_P(VALUE obj)
+{
+    return RB_TYPE_P(obj, T_STRING) && FL_TEST_RAW(obj, STR_CHILLED);
+}
+
+static inline void
+CHILLED_STRING_MUTATED(VALUE str)
+{
+    VALUE chilled_reason = RB_FL_TEST_RAW(str, STR_CHILLED);
+    FL_UNSET_RAW(str, STR_CHILLED);
+    switch (chilled_reason) {
+      case STR_CHILLED_SYMBOL_TO_S:
+        rb_warn_unchilled_symbol_to_s(str);
+        break;
+      case STR_CHILLED_LITERAL:
+        rb_warn_unchilled_literal(str);
+        break;
+      default:
+        rb_bug("RString was chilled for multiple reasons");
+    }
+}
+
+static inline bool
 is_ascii_string(VALUE str)
 {
     return rb_enc_str_coderange(str) == ENC_CODERANGE_7BIT;