/*
 * Copyright (c) 2016, 2023, 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
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#include "precompiled.hpp"
#include "gc/z/zAddress.inline.hpp"
#include "gc/z/zForwarding.inline.hpp"
#include "gc/z/zForwardingAllocator.inline.hpp"
#include "gc/z/zGeneration.inline.hpp"
#include "gc/z/zGlobals.hpp"
#include "gc/z/zHeap.hpp"
#include "gc/z/zPage.inline.hpp"
#include "runtime/os.hpp"
#include "unittest.hpp"

using namespace testing;

#define CAPTURE_DELIM "\n"
#define CAPTURE1(expression) #expression << " evaluates to " << expression
#define CAPTURE2(e0, e1)                 CAPTURE1(e0) << CAPTURE_DELIM << CAPTURE1(e1)

#define CAPTURE(expression) CAPTURE1(expression)

class ZForwardingTest : public Test {
public:
  // Setup and tear down
  ZHeap*            _old_heap;
  ZGenerationOld*   _old_old;
  ZGenerationYoung* _old_young;
  char*             _reserved;
  static size_t     _page_offset;

  char* reserve_page_memory() {
    // Probe for a free 2MB region inside the usable address range.
    // Inspired by ZVirtualMemoryManager::reserve_contiguous.
    const size_t unused = ZAddressOffsetMax - ZGranuleSize;
    const size_t increment = MAX2(align_up(unused / 100, ZGranuleSize), ZGranuleSize);

    for (uintptr_t start = 0; start + ZGranuleSize <= ZAddressOffsetMax; start += increment) {
      char* const reserved = os::attempt_reserve_memory_at((char*)ZAddressHeapBase + start, ZGranuleSize, false /* executable */);
      if (reserved != nullptr) {
        // Success
        return reserved;
      }
    }

    // Failed
    return nullptr;
  }

  virtual void SetUp() {
    ZGlobalsPointers::initialize();
    _old_heap = ZHeap::_heap;
    ZHeap::_heap = (ZHeap*)os::malloc(sizeof(ZHeap), mtTest);

    _old_old = ZGeneration::_old;
    _old_young = ZGeneration::_young;

    ZGeneration::_old = &ZHeap::_heap->_old;
    ZGeneration::_young = &ZHeap::_heap->_young;

    *const_cast<ZGenerationId*>(&ZGeneration::_old->_id) = ZGenerationId::old;
    *const_cast<ZGenerationId*>(&ZGeneration::_young->_id) = ZGenerationId::young;

    ZGeneration::_old->_seqnum = 1;
    ZGeneration::_young->_seqnum = 2;

    // Preconditions for reserve_free_granule()
    ASSERT_NE(ZAddressHeapBase, 0u);
    ASSERT_NE(ZAddressOffsetMax, 0u);
    ASSERT_NE(ZGranuleSize, 0u);

    _reserved = nullptr;

    // Find a suitable address for the testing page
    char* reserved = reserve_page_memory();

    ASSERT_NE(reserved, nullptr) << "Failed to reserve the page granule. Test needs tweaking";
    ASSERT_GE(reserved, (char*)ZAddressHeapBase);
    ASSERT_LT(reserved, (char*)ZAddressHeapBase + ZAddressOffsetMax);

    _reserved = reserved;

    os::commit_memory((char*)_reserved, ZGranuleSize, false /* executable */);

    _page_offset = uintptr_t(_reserved) - ZAddressHeapBase;
  }

  virtual void TearDown() {
    os::free(ZHeap::_heap);
    ZHeap::_heap = _old_heap;
    ZGeneration::_old = _old_old;
    ZGeneration::_young = _old_young;
    if (_reserved != nullptr) {
      os::uncommit_memory((char*)_reserved, ZGranuleSize, false /* executable */);
      os::release_memory((char*)_reserved, ZGranuleSize);
    }
  }

  // Helper functions

  class SequenceToFromIndex : AllStatic {
  public:
    static uintptr_t even(size_t sequence_number) {
      return sequence_number * 2;
    }
    static uintptr_t odd(size_t sequence_number) {
      return even(sequence_number) + 1;
    }
    static uintptr_t one_to_one(size_t sequence_number) {
      return sequence_number;
    }
  };

  // Test functions

  static void setup(ZForwarding* forwarding) {
    EXPECT_PRED1(is_power_of_2<size_t>, forwarding->_entries.length()) << CAPTURE(forwarding->_entries.length());
  }

  static void find_empty(ZForwarding* forwarding) {
    size_t size = forwarding->_entries.length();
    size_t entries_to_check = size * 2;

    for (size_t i = 0; i < entries_to_check; i++) {
      uintptr_t from_index = SequenceToFromIndex::one_to_one(i);

      ZForwardingCursor cursor;
      ZForwardingEntry entry = forwarding->find(from_index, &cursor);
      EXPECT_FALSE(entry.populated()) << CAPTURE2(from_index, size);
    }
  }

  static void find_full(ZForwarding* forwarding) {
    size_t size = forwarding->_entries.length();
    size_t entries_to_populate = size;

    // Populate
    for (size_t i = 0; i < entries_to_populate; i++) {
      uintptr_t from_index = SequenceToFromIndex::one_to_one(i);

      ZForwardingCursor cursor;
      ZForwardingEntry entry = forwarding->find(from_index, &cursor);
      ASSERT_FALSE(entry.populated()) << CAPTURE2(from_index, size);

      forwarding->insert(from_index, zoffset(from_index), &cursor);
    }

    // Verify
    for (size_t i = 0; i < entries_to_populate; i++) {
      uintptr_t from_index = SequenceToFromIndex::one_to_one(i);

      ZForwardingCursor cursor;
      ZForwardingEntry entry = forwarding->find(from_index, &cursor);
      ASSERT_TRUE(entry.populated()) << CAPTURE2(from_index, size);

      ASSERT_EQ(entry.from_index(), from_index) << CAPTURE(size);
      ASSERT_EQ(entry.to_offset(), from_index) << CAPTURE(size);
    }
  }

  static void find_every_other(ZForwarding* forwarding) {
    size_t size = forwarding->_entries.length();
    size_t entries_to_populate = size / 2;

    // Populate even from indices
    for (size_t i = 0; i < entries_to_populate; i++) {
      uintptr_t from_index = SequenceToFromIndex::even(i);

      ZForwardingCursor cursor;
      ZForwardingEntry entry = forwarding->find(from_index, &cursor);
      ASSERT_FALSE(entry.populated()) << CAPTURE2(from_index, size);

      forwarding->insert(from_index, zoffset(from_index), &cursor);
    }

    // Verify populated even indices
    for (size_t i = 0; i < entries_to_populate; i++) {
      uintptr_t from_index = SequenceToFromIndex::even(i);

      ZForwardingCursor cursor;
      ZForwardingEntry entry = forwarding->find(from_index, &cursor);
      ASSERT_TRUE(entry.populated()) << CAPTURE2(from_index, size);

      ASSERT_EQ(entry.from_index(), from_index) << CAPTURE(size);
      ASSERT_EQ(entry.to_offset(), from_index) << CAPTURE(size);
    }

    // Verify empty odd indices
    //
    // This check could be done on a larger range of sequence numbers,
    // but currently entries_to_populate is used.
    for (size_t i = 0; i < entries_to_populate; i++) {
      uintptr_t from_index = SequenceToFromIndex::odd(i);

      ZForwardingCursor cursor;
      ZForwardingEntry entry = forwarding->find(from_index, &cursor);

      ASSERT_FALSE(entry.populated()) << CAPTURE2(from_index, size);
    }
  }

  static void test(void (*function)(ZForwarding*), uint32_t size) {
    // Create page
    const ZVirtualMemory vmem(zoffset(_page_offset), ZPageSizeSmall);
    const ZPhysicalMemory pmem(ZPhysicalMemorySegment(zoffset(0), ZPageSizeSmall, true));
    ZPage page(ZPageType::small, vmem, pmem);

    page.reset(ZPageAge::eden, ZPageResetType::Allocation);

    const size_t object_size = 16;
    const zaddress object = page.alloc_object(object_size);

    ZGeneration::young()->_seqnum++;

    ZGeneration::young()->set_phase(ZGeneration::Phase::Mark);
    ZGeneration::young()->set_phase(ZGeneration::Phase::MarkComplete);
    ZGeneration::young()->set_phase(ZGeneration::Phase::Relocate);

    //page.mark_object(object, dummy, dummy);
    {
      bool dummy = false;
      const BitMap::idx_t index = page.bit_index(object);
      page._livemap.set(page._generation_id, index, dummy, dummy);
    }

    const uint32_t live_objects = size;
    const size_t live_bytes = live_objects * object_size;
    page.inc_live(live_objects, live_bytes);

    // Setup allocator
    ZForwardingAllocator allocator;
    const uint32_t nentries = ZForwarding::nentries(&page);
    allocator.reset((sizeof(ZForwarding)) + (nentries * sizeof(ZForwardingEntry)));

    // Setup forwarding
    ZForwarding* const forwarding = ZForwarding::alloc(&allocator, &page, ZPageAge::survivor1);

    // Actual test function
    (*function)(forwarding);
  }

  // Run the given function with a few different input values.
  static void test(void (*function)(ZForwarding*)) {
    test(function, 1);
    test(function, 2);
    test(function, 3);
    test(function, 4);
    test(function, 7);
    test(function, 8);
    test(function, 1023);
    test(function, 1024);
    test(function, 1025);
  }
};

TEST_VM_F(ZForwardingTest, setup) {
  test(&ZForwardingTest::setup);
}

TEST_VM_F(ZForwardingTest, find_empty) {
  test(&ZForwardingTest::find_empty);
}

TEST_VM_F(ZForwardingTest, find_full) {
  test(&ZForwardingTest::find_full);
}

TEST_VM_F(ZForwardingTest, find_every_other) {
  test(&ZForwardingTest::find_every_other);
}

size_t ZForwardingTest::_page_offset;