From 6546aed4757be07f4932326e1eb41a5d69141acf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lourens=20Naud=C3=A9?= <lourens@bearmetal.eu>
Date: Sat, 13 Apr 2019 17:05:58 +0100
Subject: [PATCH] Explicitly initialise encodings on init to remove branches on
 encoding lookup

[Misc #15806]

Closes: https://github.com/ruby/ruby/pull/2128
---
 encoding.c | 23 ++++++-----------------
 inits.c    |  1 +
 2 files changed, 7 insertions(+), 17 deletions(-)

diff --git a/encoding.c b/encoding.c
index 012d18c690..9655213f73 100644
--- a/encoding.c
+++ b/encoding.c
@@ -66,8 +66,6 @@ static struct {
 #define ENC_DUMMY_P(enc) ((enc)->ruby_encoding_index & ENC_DUMMY_FLAG)
 #define ENC_SET_DUMMY(enc) ((enc)->ruby_encoding_index |= ENC_DUMMY_FLAG)
 
-void rb_enc_init(void);
-
 #define ENCODING_COUNT ENCINDEX_BUILTIN_MAX
 #define UNSPECIFIED_ENCODING INT_MAX
 
@@ -557,9 +555,6 @@ rb_enc_alias(const char *alias, const char *orig)
     int idx;
 
     enc_check_duplication(alias);
-    if (!enc_table.list) {
-	rb_enc_init();
-    }
     if ((idx = rb_enc_find_index(orig)) < 0) {
 	return -1;
     }
@@ -613,9 +608,6 @@ rb_enc_init(void)
 rb_encoding *
 rb_enc_from_index(int index)
 {
-    if (!enc_table.list) {
-	rb_enc_init();
-    }
     if (index < 0 || enc_table.count <= (index &= ENC_INDEX_MASK)) {
 	return 0;
     }
@@ -1324,9 +1316,6 @@ enc_m_loader(VALUE klass, VALUE str)
 rb_encoding *
 rb_ascii8bit_encoding(void)
 {
-    if (!enc_table.list) {
-	rb_enc_init();
-    }
     return enc_table.list[ENCINDEX_ASCII].enc;
 }
 
@@ -1339,9 +1328,6 @@ rb_ascii8bit_encindex(void)
 rb_encoding *
 rb_utf8_encoding(void)
 {
-    if (!enc_table.list) {
-	rb_enc_init();
-    }
     return enc_table.list[ENCINDEX_UTF_8].enc;
 }
 
@@ -1354,9 +1340,6 @@ rb_utf8_encindex(void)
 rb_encoding *
 rb_usascii_encoding(void)
 {
-    if (!enc_table.list) {
-	rb_enc_init();
-    }
     return enc_table.list[ENCINDEX_US_ASCII].enc;
 }
 
@@ -1933,6 +1916,12 @@ rb_enc_aliases(VALUE klass)
  *
  */
 
+void
+Init_encodings(void)
+{
+    rb_enc_init();
+}
+
 void
 Init_Encoding(void)
 {
diff --git a/inits.c b/inits.c
index ad34223e36..75ee976192 100644
--- a/inits.c
+++ b/inits.c
@@ -22,6 +22,7 @@ rb_call_inits(void)
     CALL(vm_postponed_job);
     CALL(Method);
     CALL(RandomSeedCore);
+    CALL(encodings);
     CALL(sym);
     CALL(var_tables);
     CALL(Object);