8341664: ReferenceClassDescImpl cache internalName

Reviewed-by: liach

src/java.base/share/classes/jdk/internal/classfile/impl/AbstractPoolEntry.java

@@ -382,38 +382,6 @@ public abstract sealed class AbstractPoolEntry {
                 return stringValue().equals(u.stringValue());
         }
 
-        /**
-         * Returns if this utf8 entry's content equals a substring
-         * of {@code s} obtained as {@code s.substring(start, end - start)}.
-         * This check avoids a substring allocation.
-         */
-        public boolean equalsRegion(String s, int start, int end) {
-            // start and end values trusted
-            if (state == State.RAW)
-                inflate();
-            int len = charLen;
-            if (len != end - start)
-                return false;
-
-            var sv = stringValue;
-            if (sv != null) {
-                return sv.regionMatches(0, s, start, len);
-            }
-
-            var chars = this.chars;
-            if (chars != null) {
-                for (int i = 0; i < len; i++)
-                    if (chars[i] != s.charAt(start + i))
-                        return false;
-            } else {
-                var bytes = this.rawBytes;
-                for (int i = 0; i < len; i++)
-                    if (bytes[offset + i] != s.charAt(start + i))
-                        return false;
-            }
-            return true;
-        }
-
         @Override
         public boolean equalsString(String s) {
             if (state == State.RAW)

src/java.base/share/classes/jdk/internal/classfile/impl/SplitConstantPool.java

@@ -394,24 +394,6 @@ public final class SplitConstantPool implements ConstantPoolBuilder {
         return null;
     }
 
-    private AbstractPoolEntry.Utf8EntryImpl tryFindUtf8OfRegion(int hash, String target, int start, int end) {
-        EntryMap map = map();
-        while (true) {
-            for (int token = map.firstToken(hash); token != -1; token = map.nextToken(hash, token)) {
-                PoolEntry e = entryByIndex(map.getIndexByToken(token));
-                if (e.tag() == TAG_UTF8
-                        && e instanceof AbstractPoolEntry.Utf8EntryImpl ce
-                        && ce.equalsRegion(target, start, end))
-                    return ce;
-            }
-            if (!doneFullScan) {
-                fullScan();
-                continue;
-            }
-            return null;
-        }
-    }
-
     private AbstractPoolEntry.ClassEntryImpl tryFindClassOrInterface(int hash, ClassDesc cd) {
         while (true) {
             EntryMap map = map();
@@ -429,8 +411,7 @@ public final class SplitConstantPool implements ConstantPoolBuilder {
                     }
 
                     // no symbol available
-                    var desc = cd.descriptorString();
+                    if (ce.ref1.equalsString(Util.toInternalName(cd))) {
-                    if (ce.ref1.equalsRegion(desc, 1, desc.length() - 1)) {
                         // definite match, propagate symbol
                         ce.sym = cd;
                         return ce;
@@ -454,10 +435,11 @@ public final class SplitConstantPool implements ConstantPoolBuilder {
         if (ce != null)
             return ce;
 
-        var utfHash = Util.internalNameHash(desc);
+        String internalName = Util.toInternalName(cd);
-        var utf = tryFindUtf8OfRegion(AbstractPoolEntry.hashString(utfHash), desc, 1, desc.length() - 1);
+        var utfHash = internalName.hashCode();
+        var utf = tryFindUtf8(AbstractPoolEntry.hashString(utfHash), internalName);
         if (utf == null)
-            utf = internalAdd(new AbstractPoolEntry.Utf8EntryImpl(this, size, ConstantUtils.dropFirstAndLastChar(desc), utfHash));
+            utf = internalAdd(new AbstractPoolEntry.Utf8EntryImpl(this, size, internalName, utfHash));
 
         return internalAdd(new AbstractPoolEntry.ClassEntryImpl(this, size, utf, hash, cd));
     }

src/java.base/share/classes/jdk/internal/classfile/impl/Util.java

@@ -42,6 +42,7 @@ import java.util.function.Consumer;
 import java.util.function.Function;
 
 import jdk.internal.access.SharedSecrets;
+import jdk.internal.constant.ReferenceClassDescImpl;
 import jdk.internal.vm.annotation.ForceInline;
 import jdk.internal.vm.annotation.Stable;
 
@@ -133,10 +134,10 @@ public class Util {
     }
 
     public static String toInternalName(ClassDesc cd) {
-        var desc = cd.descriptorString();
+        if (cd instanceof ReferenceClassDescImpl rcd) {
-        if (desc.charAt(0) == 'L')
+            return rcd.internalName();
-            return desc.substring(1, desc.length() - 1);
+        }
-        throw new IllegalArgumentException(desc);
+        throw new IllegalArgumentException(cd.descriptorString());
     }
 
     public static ClassDesc toClassDesc(String classInternalNameOrArrayDesc) {
@@ -321,15 +322,6 @@ public class Util {
         boolean writeLocalTo(BufWriterImpl buf);
     }
 
-    /**
-     * Returns the hash code of an internal name given the class or interface L descriptor.
-     */
-    public static int internalNameHash(String desc) {
-        if (desc.length() > 0xffff)
-            throw new IllegalArgumentException("String too long: ".concat(Integer.toString(desc.length())));
-        return (desc.hashCode() - pow31(desc.length() - 1) * 'L' - ';') * INVERSE_31;
-    }
-
     /**
      * Returns the hash code of a class or interface L descriptor given the internal name.
      */

src/java.base/share/classes/jdk/internal/constant/ReferenceClassDescImpl.java

@@ -27,6 +27,7 @@ package jdk.internal.constant;
 import java.lang.constant.ClassDesc;
 import java.lang.invoke.MethodHandles;
 
+import jdk.internal.vm.annotation.Stable;
 import static jdk.internal.constant.ConstantUtils.*;
 
 /**
@@ -36,6 +37,7 @@ import static jdk.internal.constant.ConstantUtils.*;
  */
 public final class ReferenceClassDescImpl implements ClassDesc {
     private final String descriptor;
+    private @Stable String internalName;
 
     private ReferenceClassDescImpl(String descriptor) {
         this.descriptor = descriptor;
@@ -76,6 +78,16 @@ public final class ReferenceClassDescImpl implements ClassDesc {
         return descriptor;
     }
 
+    public String internalName() {
+        var internalName = this.internalName;
+        if (internalName == null) {
+            var desc = this.descriptor;
+            this.internalName = internalName = desc.charAt(0) == 'L' ? dropFirstAndLastChar(desc) : desc;
+        }
+
+        return internalName;
+    }
+
     @Override
     public Class<?> resolveConstantDesc(MethodHandles.Lookup lookup)
             throws ReflectiveOperationException {
@@ -90,7 +102,7 @@ public final class ReferenceClassDescImpl implements ClassDesc {
                 clazz = clazz.arrayType();
             return clazz;
         }
-        return lookup.findClass(internalToBinary(dropFirstAndLastChar(descriptor)));
+        return lookup.findClass(internalToBinary(internalName()));
     }
 
     /**

test/jdk/jdk/classfile/UtilTest.java

@@ -103,20 +103,6 @@ class UtilTest {
         }
     }
 
-    @ParameterizedTest
-    @ValueSource(classes = {
-            Long.class,
-            Object.class,
-            Util.class,
-            Test.class,
-            CopyOnWriteArrayList.class,
-            AtomicReferenceFieldUpdater.class
-    })
-    void testInternalNameHash(Class<?> type) {
-        var cd = type.describeConstable().orElseThrow();
-        assertEquals(ConstantUtils.binaryToInternal(type.getName()).hashCode(), Util.internalNameHash(cd.descriptorString()));
-    }
-
     // Ensures the initialization statement of the powers array is filling in the right values
     @Test
     void testPowersArray() {