src/jdk.vm.ci/share/classes/jdk.vm.ci.code/src/jdk/vm/ci/code/DataSection.java

@@ -20,19 +20,22 @@
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
 package jdk.vm.ci.code;
 
-import static jdk.vm.ci.meta.MetaUtil.*;
+import static jdk.vm.ci.meta.MetaUtil.identityHashCodeString;
 
-import java.nio.*;
-import java.util.*;
-import java.util.function.*;
-
-import jdk.vm.ci.code.CompilationResult.*;
-import jdk.vm.ci.code.DataSection.*;
-import jdk.vm.ci.meta.*;
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.Objects;
+import java.util.function.Consumer;
+
+import jdk.vm.ci.code.CompilationResult.DataPatch;
+import jdk.vm.ci.code.CompilationResult.DataSectionReference;
+import jdk.vm.ci.code.DataSection.Data;
+import jdk.vm.ci.meta.SerializableConstant;
 
 public final class DataSection implements Iterable<Data> {
 
     @FunctionalInterface
     public interface DataBuilder {

@@ -174,16 +177,32 @@
      * @param data the {@link Data} item to be inserted
      * @return a unique {@link DataSectionReference} identifying the {@link Data} item
      */
     public DataSectionReference insertData(Data data) {
         assert !finalLayout;
+        synchronized (data) {
         if (data.ref == null) {
             data.ref = new DataSectionReference();
             dataItems.add(data);
         }
         return data.ref;
     }
+    }
+
+    /**
+     * Transfers all {@link Data} from the provided other {@link DataSection} to this
+     * {@link DataSection}, and empties the other section.
+     */
+    public void addAll(DataSection other) {
+        assert !finalLayout && !other.finalLayout;
+
+        for (Data data : other.dataItems) {
+            assert data.ref != null;
+            dataItems.add(data);
+        }
+        other.dataItems.clear();
+    }
 
     /**
      * Compute the layout of the data section. This can be called only once, and after it has been
      * called, the data section can no longer be modified.
      */

@@ -193,18 +212,20 @@
 
         // simple heuristic: put items with larger alignment requirement first
         dataItems.sort((a, b) -> a.alignment - b.alignment);
 
         int position = 0;
+        int alignment = 1;
         for (Data d : dataItems) {
-            sectionAlignment = lcm(sectionAlignment, d.alignment);
+            alignment = lcm(alignment, d.alignment);
             position = align(position, d.alignment);
 
             d.ref.setOffset(position);
             position += d.size;
         }
 
+        sectionAlignment = alignment;
         sectionSize = position;
     }
 
     public boolean isFinalized() {
         return finalLayout;