DexPool writeTo() very slow on R$id

[7aGiven]

I use dexlib2-3.0.9 to modify dex.

DexBackedDexFile dexFile = ?;
MemoryDataStore memoryDataStore = new MemoryDataStore();
DexRewriter dexRewriter = new DexRewriter(new MyRewriterModule());
Rewriter<DexFile> dexFileRewriter = dexRewriter.getDexFileRewriter();
DexPool.writeTo(memoryDataStore, dexFileRewriter.rewrite(dexNative.dexFile));

Now, When parse and write R$id or R$string or R$drawable (include 20000+ field), very slow for more than 60s.

I trace code for dexlib2, and locate at here:

public class ClassPool extends ... {
  ...
  public void intern(@Nonnull ClassDef classDef) {
    ...
    HashSet<String> fields = new HashSet<String>();
    for (Field field: poolClassDef.getFields()) {
      String fieldDescriptor = DexFormatter.INSTANCE.getShortFieldDescriptor(field);
      if (!fields.add(fieldDescriptor)) {
        throw new ExceptionWithContext("Multiple definitions for field %s->%s",
          poolClassDef.getType(), fieldDescriptor);
      }
      dexPool.fieldSection.intern(field);

      EncodedValue initialValue = field.getInitialValue();
      if (initialValue != null) {
        dexPool.internEncodedValue(initialValue);
      }

      dexPool.annotationSetSection.intern(field.getAnnotations());

      ArrayEncodedValue staticInitializers = getStaticInitializers(poolClassDef);
      if (staticInitializers != null) {
        dexPool.encodedArraySection.intern(staticInitializers);
      }
    }
    ...
  }
  ...
}

OK, maybe I found it, it call dexPool.encodedArraySection.intern(staticInitializers); for every field.

So I move "staticInitializers" out of loop, OK, it look like No Problem, and it be very fast!

I'm wondering if this is a dexlib2 coding bug?

[7aGiven]

I test it.

Process a apk include 40 dex, need 20 min.

after move "staticInitializers" out of loop, The time was shortened to 5 minutes.

No difference in DEX comparison.

I don't know if it's useful for "call dexPool.encodedArraySection.intern(staticInitializers); for every field". because I didn't read all source code about DexPool.