[GR-59419] Implement compact constant pools.

espresso/src/com.oracle.truffle.espresso.classfile/src/com/oracle/truffle/espresso/classfile/ExceptionHandler.java

@@ -34,10 +34,10 @@ public final class ExceptionHandler {
 
     public static final ExceptionHandler[] EMPTY_ARRAY = new ExceptionHandler[0];
 
-    private final int startBCI;
-    private final int endBCI;
-    private final int handlerBCI;
-    private final int catchTypeCPI;
+    private final char startBCI;
+    private final char endBCI;
+    private final char handlerBCI;
+    private final char catchTypeCPI;
     private final Symbol<Type> catchType;
 
     /**
@@ -50,10 +50,10 @@ public final class ExceptionHandler {
      * @param catchType the type caught by this exception handler
      */
     public ExceptionHandler(int startBCI, int endBCI, int catchBCI, int catchTypeCPI, Symbol<Type> catchType) {
-        this.startBCI = startBCI;
-        this.endBCI = endBCI;
-        this.handlerBCI = catchBCI;
-        this.catchTypeCPI = catchTypeCPI;
+        this.startBCI = (char) startBCI;
+        this.endBCI = (char) endBCI;
+        this.handlerBCI = (char) catchBCI;
+        this.catchTypeCPI = (char) catchTypeCPI;
         this.catchType = catchType;
     }
 
@@ -124,7 +124,8 @@ public boolean equals(Object obj) {
 
     @Override
     public String toString() {
-        return "ExceptionHandler<startBCI=" + startBCI + ", endBCI=" + endBCI + ", handlerBCI=" + handlerBCI + ", catchTypeCPI=" + catchTypeCPI + ", catchType=" + catchType + ">";
+        return "ExceptionHandler<startBCI=" + getStartBCI() + ", endBCI=" + getEndBCI() + ", handlerBCI=" + getHandlerBCI() + ", catchTypeCPI=" + getCatchType() + ", catchType=" + getCatchType() +
+                        ">";
     }
 
     @Override

espresso/src/com.oracle.truffle.espresso.classfile/src/com/oracle/truffle/espresso/classfile/ParserConstantPool.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2025, 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.truffle.espresso.classfile;
+
+import java.util.Arrays;
+
+import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
+import com.oracle.truffle.espresso.classfile.descriptors.Symbol;
+
+public final class ParserConstantPool extends ConstantPool {
+
+    public ParserConstantPool(byte[] tags, int[] entries, Symbol<?>[] symbols, int majorVersion, int minorVersion) {
+        super(tags, entries, symbols, majorVersion, minorVersion);
+    }
+
+    @Override
+    @TruffleBoundary
+    public RuntimeException classFormatError(String message) {
+        throw new ParserException.ClassFormatError(message);
+    }
+
+    @Override
+    public ParserConstantPool getParserConstantPool() {
+        return this;
+    }
+
+    public ParserConstantPool patchForHiddenClass(int thisKlassIndex, Symbol<?> newName) {
+        int newNameIndex = entries.length;
+        int newSymbolIndex = symbols.length;
+
+        byte[] newTags = Arrays.copyOf(tags, tags.length + 1);
+        int[] newEntries = Arrays.copyOf(entries, entries.length + 1);
+        Symbol<?>[] newSymbols = Arrays.copyOf(symbols, symbols.length + 1);
+
+        // Append a new UTF8 constant.
+        newSymbols[newSymbolIndex] = newName;
+        newTags[newNameIndex] = CONSTANT_Utf8;
+        newEntries[newNameIndex] = newSymbolIndex;
+
+        // Patch hidden class name index.
+        newEntries[thisKlassIndex] = newNameIndex;
+
+        // This will get resolved in the ObjectKlass constructor
+        // See initSelfReferenceInPool
+        return new ParserConstantPool(newTags, newEntries, newSymbols, majorVersion, minorVersion);
+    }
+
+}

espresso/src/com.oracle.truffle.espresso.classfile/src/com/oracle/truffle/espresso/classfile/ParserKlass.java

@@ -55,12 +55,12 @@ public final class ParserKlass {
     /**
      * Unresolved constant pool, only trivial entries (with no resolution involved) are computed.
      */
-    private final ImmutableConstantPool pool;
+    private final ParserConstantPool pool;
 
     private final int thisKlassIndex;
     private final long hiddenKlassId;
 
-    public ParserKlass(ImmutableConstantPool pool,
+    public ParserKlass(ParserConstantPool pool,
                     int flags,
                     Symbol<Name> name,
                     Symbol<Type> type,
@@ -112,7 +112,7 @@ public Symbol<Type>[] getSuperInterfaces() {
         return superInterfaces;
     }
 
-    public ImmutableConstantPool getConstantPool() {
+    public ParserConstantPool getConstantPool() {
         return pool;
     }
 

espresso/src/com.oracle.truffle.espresso.classfile/src/com/oracle/truffle/espresso/classfile/ParsingContext.java

@@ -24,8 +24,8 @@
 
 import java.util.function.Supplier;
 
-import com.oracle.truffle.espresso.classfile.constantpool.Utf8Constant;
 import com.oracle.truffle.espresso.classfile.descriptors.ByteSequence;
+import com.oracle.truffle.espresso.classfile.descriptors.ModifiedUTF8;
 import com.oracle.truffle.espresso.classfile.descriptors.Name;
 import com.oracle.truffle.espresso.classfile.descriptors.Symbol;
 import com.oracle.truffle.espresso.classfile.descriptors.Type;
@@ -47,7 +47,7 @@ public interface ParsingContext {
 
     Symbol<Type> getOrCreateTypeFromName(ByteSequence byteSequence);
 
-    Utf8Constant getOrCreateUtf8Constant(ByteSequence byteSequence);
+    Symbol<? extends ModifiedUTF8> getOrCreateUtf8(ByteSequence byteSequence);
 
     interface Logger {
         void log(String message);

espresso/src/com.oracle.truffle.espresso.classfile/src/com/oracle/truffle/espresso/classfile/attributes/Attribute.java

@@ -25,35 +25,26 @@
 import java.util.Arrays;
 import java.util.Objects;
 
-import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
 import com.oracle.truffle.espresso.classfile.ConstantPool;
 import com.oracle.truffle.espresso.classfile.descriptors.Name;
+import com.oracle.truffle.espresso.classfile.descriptors.ParserSymbols.ParserNames;
 import com.oracle.truffle.espresso.classfile.descriptors.Symbol;
 
-public class Attribute {
+public abstract class Attribute {
 
     public static final Attribute[] EMPTY_ARRAY = new Attribute[0];
 
-    private final Symbol<Name> name;
+    // Singleton instance for the Synthetic attribute.
+    public static final Attribute SYNTHETIC = createRaw(ParserNames.Synthetic, null);
 
-    @CompilationFinal(dimensions = 1) //
-    private final byte[] data;
-
-    public final Symbol<Name> getName() {
-        return name;
-    }
+    public abstract Symbol<Name> getName();
 
     /**
      * Attribute raw data. Known attributes that parse the raw data, can drop the raw data (return
      * null).
      */
-    public final byte[] getData() {
-        return data;
-    }
-
-    public Attribute(Symbol<Name> name, final byte[] data) {
-        this.name = name;
-        this.data = data;
+    public byte[] getData() {
+        return null;
     }
 
     /**
@@ -70,6 +61,20 @@ public boolean isSame(Attribute other, ConstantPool thisPool, ConstantPool other
         if (other == null || getClass() != other.getClass()) {
             return false;
         }
-        return Objects.equals(name, other.name) && Arrays.equals(data, other.data);
+        return Objects.equals(getName(), other.getName()) && Arrays.equals(getData(), other.getData());
+    }
+
+    public static Attribute createRaw(Symbol<Name> name, byte[] data) {
+        return new Attribute() {
+            @Override
+            public Symbol<Name> getName() {
+                return name;
+            }
+
+            @Override
+            public byte[] getData() {
+                return data;
+            }
+        };
     }
 }

espresso/src/com.oracle.truffle.espresso.classfile/src/com/oracle/truffle/espresso/classfile/attributes/BootstrapMethodsAttribute.java

@@ -63,11 +63,16 @@ public char getBootstrapMethodRef() {
     private final Entry[] entries;
 
     public BootstrapMethodsAttribute(Symbol<Name> name, Entry[] entries) {
-        super(name, null);
+        assert name == NAME;
         this.entries = entries;
     }
 
     public Entry at(int index) {
         return entries[index];
     }
+
+    @Override
+    public Symbol<Name> getName() {
+        return NAME;
+    }
 }