test_metaspaceClosure.cpp

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#include "precompiled.hpp"
#include "memory/allocation.hpp"
#include "memory/metadataFactory.hpp"
#include "memory/metaspaceClosure.hpp"
#include "oops/array.hpp"
#include "oops/metadata.hpp"
#include "runtime/thread.hpp"
#include "unittest.hpp"

class MyMetaData : public MetaspaceObj {
public:
  MyMetaData* _a;
  MyMetaData* _b;

  MyMetaData() : _a(NULL), _b(NULL) {}

  MetaspaceObj::Type type() const {
    return MetaspaceObj::SymbolType; // Just lie. It doesn't matter in this test
  }
  const char* internal_name()  const {
    return "MyMetaData";
  }
  int size() const {
    return align_up((int)sizeof(MyMetaData), wordSize) / wordSize;
  };

  static bool is_read_only_by_default() {
    return true;
  }

  void metaspace_pointers_do(MetaspaceClosure* it) {
    it->push(&_a);
    it->push(&_b);
  }
};

class MyUniqueMetaspaceClosure : public MetaspaceClosure {
  static constexpr int SIZE = 10;
  MyMetaData* _visited[SIZE];
  int _count;
public:
  MyUniqueMetaspaceClosure() {
    for (int i = 0; i < SIZE; i++) {
      _visited[i] = NULL;
    }
    _count = 0;
  }

  virtual bool do_ref(Ref* ref, bool read_only) {
    MyMetaData* ptr = (MyMetaData*)ref->obj();
    assert(_count < SIZE, "out of bounds");
    _visited[_count++] = ptr;
    return true; // recurse
  }

  bool has_visited(MyMetaData* p) {
    for (int i = 0; i < SIZE; i++) {
      if (_visited[i] == p) {
        return true;
      }
    }
    return false;
  }
};

// iterate an Array<MyMetaData*>
TEST_VM(MetaspaceClosure, MSOPointerArrayRef) {
  JavaThread* THREAD = JavaThread::current();
  ClassLoaderData* cld = ClassLoaderData::the_null_class_loader_data();
  Array<MyMetaData*>* array = MetadataFactory::new_array<MyMetaData*>(cld, 4, THREAD);
  for (int i = 0; i < array->length(); i++) {
    EXPECT_TRUE(array->at(i) == NULL) << "should be initialized to null";
  }

  MyMetaData x;
  MyMetaData y;
  MyMetaData z;

  array->at_put(0, &x);
  array->at_put(2, &y);
  y._a = &z;

  MyUniqueMetaspaceClosure closure;
  closure.push(&array);

  EXPECT_TRUE(closure.has_visited(&x)) << "must be";
  EXPECT_TRUE(closure.has_visited(&y)) << "must be";
  EXPECT_TRUE(closure.has_visited(&z)) << "must be";
}

// iterate an Array<MyMetaData>
TEST_VM(MetaspaceClosure, MSOArrayRef) {
  JavaThread* THREAD = JavaThread::current();
  ClassLoaderData* cld = ClassLoaderData::the_null_class_loader_data();
  Array<MyMetaData>* array = MetadataFactory::new_array<MyMetaData>(cld, 4, THREAD);
  for (int i = 0; i < array->length(); i++) {
    EXPECT_TRUE(array->at(i)._a == NULL) << "should be initialized to null";
    EXPECT_TRUE(array->at(i)._b == NULL) << "should be initialized to null";
  }

  MyMetaData x;
  MyMetaData y;
  MyMetaData z;

  array->adr_at(0)->_a = &x;
  array->adr_at(2)->_b = &y;
  y._a = &z;

  MyUniqueMetaspaceClosure closure;
  closure.push(&array);

  EXPECT_TRUE(closure.has_visited(&x)) << "must be";
  EXPECT_TRUE(closure.has_visited(&y)) << "must be";
  EXPECT_TRUE(closure.has_visited(&z)) << "must be";
}