[GR-40766] Optimize conversion of j.l.String to TruffleString via InteropLibrary#asTruffleString()

PullRequest: graal/12571

Author: eregon

truffle/src/com.oracle.truffle.api.interop/src/com/oracle/truffle/api/interop/DefaultStringExports.java

@@ -41,9 +41,11 @@
 package com.oracle.truffle.api.interop;
 
 import com.oracle.truffle.api.TruffleLanguage;
+import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.library.ExportLibrary;
 import com.oracle.truffle.api.library.ExportMessage;
 import com.oracle.truffle.api.source.SourceSection;
+import com.oracle.truffle.api.strings.TruffleString;
 
 @ExportLibrary(value = InteropLibrary.class, receiverType = String.class)
 @SuppressWarnings("unused")
@@ -59,6 +61,12 @@ static String asString(String receiver) {
         return receiver;
     }
 
+    @ExportMessage
+    static TruffleString asTruffleString(String receiver,
+                    @Cached TruffleString.FromJavaStringNode fromJavaStringNode) {
+        return fromJavaStringNode.execute(receiver, TruffleString.Encoding.UTF_16);
+    }
+
     /*
      * We export these messages explicitly because the legacy default is very costly. Remove with
      * the complicated legacy implementation in InteropLibrary.

truffle/src/com.oracle.truffle.api.strings/src/com/oracle/truffle/api/strings/TStringInternalNodes.java

@@ -1542,7 +1542,8 @@ TruffleString doNonEmpty(String javaString, int charOffset, int length, final bo
             TruffleString ret = TruffleString.createFromArray(array, offset, length, stride, Encoding.UTF_16, codePointLength, codeRange);
             if (length == javaString.length()) {
                 assert charOffset == 0;
-                ret.cacheInsert(TruffleString.createWrapJavaString(javaString, codePointLength, codeRange));
+                TruffleString wrapped = TruffleString.createWrapJavaString(javaString, codePointLength, codeRange);
+                ret.cacheInsertFirstBeforePublished(wrapped);
             }
             return ret;
         }

truffle/src/com.oracle.truffle.api.strings/src/com/oracle/truffle/api/strings/TruffleString.java

@@ -140,7 +140,7 @@ private static VarHandle initializeNextUpdater() {
 
     private final int codePointLength;
     private final byte codeRange;
-    private TruffleString next;
+    TruffleString next;
 
     private TruffleString(Object data, int offset, int length, int stride, Encoding encoding, int codePointLength, int codeRange, boolean isCacheHead) {
         super(data, offset, length, stride, encoding, isCacheHead ? FLAG_CACHE_HEAD : 0);
@@ -305,6 +305,20 @@ void cacheInsert(TruffleString entry) {
         } while (!setNextAtomic(cacheHead, cacheHeadNext, entry));
     }
 
+    /*
+     * Simpler and faster insertion for the case `this` and `entry` were just allocated together and
+     * before they are published. The CAS is not needed in that case since we know nobody could
+     * write to `next` fields before us.
+     */
+    void cacheInsertFirstBeforePublished(TruffleString entry) {
+        assert !entry.isCacheHead();
+        assert isCacheHead();
+        assert next == null;
+        TruffleString cacheHead = this;
+        entry.next = cacheHead;
+        cacheHead.next = entry;
+    }
+
     private static boolean hasDuplicateEncoding(TruffleString cacheHead, TruffleString start, TruffleString insertEntry) {
         if (start == null) {
             return false;
@@ -2024,7 +2038,7 @@ public abstract static class FromJavaStringNode extends Node {
          * @since 22.1
          */
         public final TruffleString execute(String value, Encoding encoding) {
-            return execute(value, 0, value.length(), encoding, true);
+            return execute(value, 0, value.length(), encoding, false);
         }
 
         /**