Avoid creating an extra TruffleString for visitStringNode()

Author: eregon

src/main/java/org/truffleruby/core/string/FrozenStringLiterals.java

@@ -38,7 +38,8 @@ public FrozenStringLiterals(TStringCache tStringCache) {
 
     @TruffleBoundary
     public ImmutableRubyString getFrozenStringLiteral(TruffleString tstring, RubyEncoding encoding) {
-        return getFrozenStringLiteral(tstring.getInternalByteArrayUncached(encoding.tencoding),
+        return getFrozenStringLiteral(
+                tstring.getInternalByteArrayUncached(encoding.tencoding),
                 TStringUtils.hasImmutableInternalByteArray(tstring),
                 encoding);
     }
@@ -58,6 +59,20 @@ public ImmutableRubyString getFrozenStringLiteral(InternalByteArray byteArray, b
         }
     }
 
+    @TruffleBoundary
+    public ImmutableRubyString getFrozenStringLiteral(byte[] bytes, RubyEncoding encoding) {
+        // Ensure all ImmutableRubyString have a TruffleString from the TStringCache
+        var cachedTString = tstringCache.getTString(bytes, encoding);
+        var tstringWithEncoding = new TStringWithEncoding(cachedTString, encoding);
+
+        final ImmutableRubyString string = values.get(tstringWithEncoding);
+        if (string != null) {
+            return string;
+        } else {
+            return values.addInCacheIfAbsent(tstringWithEncoding, new ImmutableRubyString(cachedTString, encoding));
+        }
+    }
+
     public static ImmutableRubyString createStringAndCacheLater(TruffleString name,
             RubyEncoding encoding) {
         final ImmutableRubyString string = new ImmutableRubyString(name, encoding);

src/main/java/org/truffleruby/parser/YARPTranslator.java

@@ -3152,13 +3152,13 @@ public RubyNode visitStringNode(Nodes.StringNode node) {
             encoding = sourceEncoding;
         }
 
-        final TruffleString tstring = TStringUtils.fromByteArray(node.unescaped, encoding);
+        byte[] bytes = node.unescaped;
 
         if (!node.isFrozen()) {
-            final TruffleString cachedTString = language.tstringCache.getTString(tstring, encoding);
+            final TruffleString cachedTString = language.tstringCache.getTString(bytes, encoding);
             rubyNode = new StringLiteralNode(cachedTString, encoding);
         } else {
-            final ImmutableRubyString frozenString = language.getFrozenStringLiteral(tstring, encoding);
+            ImmutableRubyString frozenString = language.frozenStringLiterals.getFrozenStringLiteral(bytes, encoding);
             rubyNode = new FrozenStringLiteralNode(frozenString, FrozenStrings.EXPRESSION);
         }