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src/hotspot/share/classfile/fieldLayoutBuilder.cpp

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*** 1,7 ***
  /*
!  * Copyright (c) 2020, 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.
--- 1,7 ---
  /*
!  * Copyright (c) 2019, 2020, 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.

*** 24,22 ***
  
  #include "precompiled.hpp"
  #include "jvm.h"
  #include "classfile/classFileParser.hpp"
  #include "classfile/fieldLayoutBuilder.hpp"
  #include "memory/resourceArea.hpp"
  #include "oops/array.hpp"
  #include "oops/fieldStreams.inline.hpp"
  #include "oops/instanceMirrorKlass.hpp"
  #include "oops/instanceKlass.inline.hpp"
  #include "oops/klass.inline.hpp"
  #include "runtime/fieldDescriptor.inline.hpp"
  
- 
  LayoutRawBlock::LayoutRawBlock(Kind kind, int size) :
    _next_block(NULL),
    _prev_block(NULL),
    _kind(kind),
    _offset(-1),
    _alignment(1),
    _size(size),
    _field_index(-1),
--- 24,25 ---
  
  #include "precompiled.hpp"
  #include "jvm.h"
  #include "classfile/classFileParser.hpp"
  #include "classfile/fieldLayoutBuilder.hpp"
+ #include "classfile/systemDictionary.hpp"
+ #include "classfile/vmSymbols.hpp"
  #include "memory/resourceArea.hpp"
  #include "oops/array.hpp"
  #include "oops/fieldStreams.inline.hpp"
  #include "oops/instanceMirrorKlass.hpp"
  #include "oops/instanceKlass.inline.hpp"
  #include "oops/klass.inline.hpp"
+ #include "oops/inlineKlass.inline.hpp"
  #include "runtime/fieldDescriptor.inline.hpp"
  
  LayoutRawBlock::LayoutRawBlock(Kind kind, int size) :
    _next_block(NULL),
    _prev_block(NULL),
+   _inline_klass(NULL),
    _kind(kind),
    _offset(-1),
    _alignment(1),
    _size(size),
    _field_index(-1),

*** 51,17 ***
  
  
  LayoutRawBlock::LayoutRawBlock(int index, Kind kind, int size, int alignment, bool is_reference) :
   _next_block(NULL),
   _prev_block(NULL),
   _kind(kind),
   _offset(-1),
   _alignment(alignment),
   _size(size),
   _field_index(index),
   _is_reference(is_reference) {
!   assert(kind == REGULAR || kind == FLATTENED || kind == INHERITED,
           "Other kind do not have a field index");
    assert(size > 0, "Sanity check");
    assert(alignment > 0, "Sanity check");
  }
  
--- 54,18 ---
  
  
  LayoutRawBlock::LayoutRawBlock(int index, Kind kind, int size, int alignment, bool is_reference) :
   _next_block(NULL),
   _prev_block(NULL),
+  _inline_klass(NULL),
   _kind(kind),
   _offset(-1),
   _alignment(alignment),
   _size(size),
   _field_index(index),
   _is_reference(is_reference) {
!   assert(kind == REGULAR || kind == INLINED || kind == INHERITED,
           "Other kind do not have a field index");
    assert(size > 0, "Sanity check");
    assert(alignment > 0, "Sanity check");
  }
  

*** 73,22 ***
    return _size >= size + adjustment;
  }
  
  FieldGroup::FieldGroup(int contended_group) :
    _next(NULL),
!   _primitive_fields(NULL),
    _oop_fields(NULL),
    _contended_group(contended_group),  // -1 means no contended group, 0 means default contended group
    _oop_count(0) {}
  
  void FieldGroup::add_primitive_field(AllFieldStream fs, BasicType type) {
    int size = type2aelembytes(type);
    LayoutRawBlock* block = new LayoutRawBlock(fs.index(), LayoutRawBlock::REGULAR, size, size /* alignment == size for primitive types */, false);
!   if (_primitive_fields == NULL) {
!     _primitive_fields = new(ResourceObj::RESOURCE_AREA, mtInternal) GrowableArray<LayoutRawBlock*>(INITIAL_LIST_SIZE);
    }
-   _primitive_fields->append(block);
  }
  
  void FieldGroup::add_oop_field(AllFieldStream fs) {
    int size = type2aelembytes(T_OBJECT);
    LayoutRawBlock* block = new LayoutRawBlock(fs.index(), LayoutRawBlock::REGULAR, size, size /* alignment == size for oops */, true);
--- 77,24 ---
    return _size >= size + adjustment;
  }
  
  FieldGroup::FieldGroup(int contended_group) :
    _next(NULL),
!   _small_primitive_fields(NULL),
+   _big_primitive_fields(NULL),
    _oop_fields(NULL),
    _contended_group(contended_group),  // -1 means no contended group, 0 means default contended group
    _oop_count(0) {}
  
  void FieldGroup::add_primitive_field(AllFieldStream fs, BasicType type) {
    int size = type2aelembytes(type);
    LayoutRawBlock* block = new LayoutRawBlock(fs.index(), LayoutRawBlock::REGULAR, size, size /* alignment == size for primitive types */, false);
!   if (size >= oopSize) {
!     add_to_big_primitive_list(block);
+   } else {
+     add_to_small_primitive_list(block);
    }
  }
  
  void FieldGroup::add_oop_field(AllFieldStream fs) {
    int size = type2aelembytes(T_OBJECT);
    LayoutRawBlock* block = new LayoutRawBlock(fs.index(), LayoutRawBlock::REGULAR, size, size /* alignment == size for oops */, true);

*** 97,16 ***
    }
    _oop_fields->append(block);
    _oop_count++;
  }
  
  void FieldGroup::sort_by_size() {
!   if (_primitive_fields != NULL) {
!     _primitive_fields->sort(LayoutRawBlock::compare_size_inverted);
    }
  }
  
  FieldLayout::FieldLayout(Array<u2>* fields, ConstantPool* cp) :
    _fields(fields),
    _cp(cp),
    _blocks(NULL),
    _start(_blocks),
--- 103,43 ---
    }
    _oop_fields->append(block);
    _oop_count++;
  }
  
+ void FieldGroup::add_inlined_field(AllFieldStream fs, InlineKlass* vk) {
+   LayoutRawBlock* block = new LayoutRawBlock(fs.index(), LayoutRawBlock::INLINED, vk->get_exact_size_in_bytes(), vk->get_alignment(), false);
+   block->set_inline_klass(vk);
+   if (block->size() >= oopSize) {
+     add_to_big_primitive_list(block);
+   } else {
+     add_to_small_primitive_list(block);
+   }
+ }
+ 
  void FieldGroup::sort_by_size() {
!   if (_small_primitive_fields != NULL) {
!     _small_primitive_fields->sort(LayoutRawBlock::compare_size_inverted);
+   }
+   if (_big_primitive_fields != NULL) {
+     _big_primitive_fields->sort(LayoutRawBlock::compare_size_inverted);
    }
  }
  
+ void FieldGroup::add_to_small_primitive_list(LayoutRawBlock* block) {
+   if (_small_primitive_fields == NULL) {
+     _small_primitive_fields = new(ResourceObj::RESOURCE_AREA, mtInternal) GrowableArray<LayoutRawBlock*>(INITIAL_LIST_SIZE);
+   }
+   _small_primitive_fields->append(block);
+ }
+ 
+ void FieldGroup::add_to_big_primitive_list(LayoutRawBlock* block) {
+   if (_big_primitive_fields == NULL) {
+     _big_primitive_fields = new(ResourceObj::RESOURCE_AREA, mtInternal) GrowableArray<LayoutRawBlock*>(INITIAL_LIST_SIZE);
+   }
+   _big_primitive_fields->append(block);
+ }
+ 
  FieldLayout::FieldLayout(Array<u2>* fields, ConstantPool* cp) :
    _fields(fields),
    _cp(cp),
    _blocks(NULL),
    _start(_blocks),

*** 136,29 ***
      insert(first_empty_block(), new LayoutRawBlock(LayoutRawBlock::RESERVED, instanceOopDesc::base_offset_in_bytes()));
    } else {
      bool has_fields = reconstruct_layout(super_klass);
      fill_holes(super_klass);
      if ((UseEmptySlotsInSupers && !super_klass->has_contended_annotations()) || !has_fields) {
!       _start = _blocks;  // start allocating fields from the first empty block
      } else {
        _start = _last;    // append fields at the end of the reconstructed layout
      }
    }
  }
  
  LayoutRawBlock* FieldLayout::first_field_block() {
!   LayoutRawBlock* block = _start;
!   while (block->kind() != LayoutRawBlock::INHERITED && block->kind() != LayoutRawBlock::REGULAR
!       && block->kind() != LayoutRawBlock::FLATTENED && block->kind() != LayoutRawBlock::PADDING) {
      block = block->next_block();
    }
    return block;
  }
  
! 
! // Insert a set of fields into a layout using a best-fit strategy.
- // For each field, search for the smallest empty slot able to fit the field
  // (satisfying both size and alignment requirements), if none is found,
  // add the field at the end of the layout.
  // Fields cannot be inserted before the block specified in the "start" argument
  void FieldLayout::add(GrowableArray<LayoutRawBlock*>* list, LayoutRawBlock* start) {
    if (list == NULL) return;
--- 169,31 ---
      insert(first_empty_block(), new LayoutRawBlock(LayoutRawBlock::RESERVED, instanceOopDesc::base_offset_in_bytes()));
    } else {
      bool has_fields = reconstruct_layout(super_klass);
      fill_holes(super_klass);
      if ((UseEmptySlotsInSupers && !super_klass->has_contended_annotations()) || !has_fields) {
!       _start = _blocks; // Setting _start to _blocks instead of _last would allow subclasses
+       // to allocate fields in empty slots of their super classes
      } else {
        _start = _last;    // append fields at the end of the reconstructed layout
      }
    }
  }
  
  LayoutRawBlock* FieldLayout::first_field_block() {
!   LayoutRawBlock* block = _blocks;
!   while (block != NULL
!          && block->kind() != LayoutRawBlock::INHERITED
+          && block->kind() != LayoutRawBlock::REGULAR
+          && block->kind() != LayoutRawBlock::INLINED) {
      block = block->next_block();
    }
    return block;
  }
  
! // Insert a set of fields into a layout.
! // For each field, search for an empty slot able to fit the field
  // (satisfying both size and alignment requirements), if none is found,
  // add the field at the end of the layout.
  // Fields cannot be inserted before the block specified in the "start" argument
  void FieldLayout::add(GrowableArray<LayoutRawBlock*>* list, LayoutRawBlock* start) {
    if (list == NULL) return;

*** 168,11 ***
    int last_alignment = 0;
    for (int i = 0; i < list->length(); i ++) {
      LayoutRawBlock* b = list->at(i);
      LayoutRawBlock* cursor = NULL;
      LayoutRawBlock* candidate = NULL;
- 
      // if start is the last block, just append the field
      if (start == last_block()) {
        candidate = last_block();
      }
      // Before iterating over the layout to find an empty slot fitting the field's requirements,
--- 203,10 ---

*** 186,10 ***
--- 220,11 ---
        last_size = b->size();
        last_alignment = b->alignment();
        cursor = last_block()->prev_block();
        assert(cursor != NULL, "Sanity check");
        last_search_success = true;
+ 
        while (cursor != start) {
          if (cursor->kind() == LayoutRawBlock::EMPTY && cursor->fit(b->size(), b->alignment())) {
            if (candidate == NULL || cursor->size() < candidate->size()) {
              candidate = cursor;
            }

*** 202,11 ***
        }
        assert(candidate != NULL, "Candidate must not be null");
        assert(candidate->kind() == LayoutRawBlock::EMPTY, "Candidate must be an empty block");
        assert(candidate->fit(b->size(), b->alignment()), "Candidate must be able to store the block");
      }
- 
      insert_field_block(candidate, b);
    }
  }
  
  // Used for classes with hard coded field offsets, insert a field at the specified offset */
--- 237,10 ---

*** 301,24 ***
      for (AllFieldStream fs(ik->fields(), ik->constants()); !fs.done(); fs.next()) {
        BasicType type = Signature::basic_type(fs.signature());
        // distinction between static and non-static fields is missing
        if (fs.access_flags().is_static()) continue;
        has_instance_fields = true;
!       int size = type2aelembytes(type);
!       // INHERITED blocks are marked as non-reference because oop_maps are handled by their holder class
!       LayoutRawBlock* block = new LayoutRawBlock(fs.index(), LayoutRawBlock::INHERITED, size, size, false);
        block->set_offset(fs.offset());
        all_fields->append(block);
      }
      ik = ik->super() == NULL ? NULL : InstanceKlass::cast(ik->super());
    }
- 
    all_fields->sort(LayoutRawBlock::compare_offset);
    _blocks = new LayoutRawBlock(LayoutRawBlock::RESERVED, instanceOopDesc::base_offset_in_bytes());
    _blocks->set_offset(0);
    _last = _blocks;
- 
    for(int i = 0; i < all_fields->length(); i++) {
      LayoutRawBlock* b = all_fields->at(i);
      _last->set_next_block(b);
      b->set_prev_block(_last);
      _last = b;
--- 335,30 ---
      for (AllFieldStream fs(ik->fields(), ik->constants()); !fs.done(); fs.next()) {
        BasicType type = Signature::basic_type(fs.signature());
        // distinction between static and non-static fields is missing
        if (fs.access_flags().is_static()) continue;
        has_instance_fields = true;
!       LayoutRawBlock* block;
!       if (type == T_INLINE_TYPE) {
!         InlineKlass* vk = InlineKlass::cast(ik->get_inline_type_field_klass(fs.index()));
+         block = new LayoutRawBlock(fs.index(), LayoutRawBlock::INHERITED, vk->get_exact_size_in_bytes(),
+                                    vk->get_alignment(), false);
+ 
+       } else {
+         int size = type2aelembytes(type);
+         // INHERITED blocks are marked as non-reference because oop_maps are handled by their holder class
+         block = new LayoutRawBlock(fs.index(), LayoutRawBlock::INHERITED, size, size, false);
+       }
        block->set_offset(fs.offset());
        all_fields->append(block);
      }
      ik = ik->super() == NULL ? NULL : InstanceKlass::cast(ik->super());
    }
    all_fields->sort(LayoutRawBlock::compare_offset);
    _blocks = new LayoutRawBlock(LayoutRawBlock::RESERVED, instanceOopDesc::base_offset_in_bytes());
    _blocks->set_offset(0);
    _last = _blocks;
    for(int i = 0; i < all_fields->length(); i++) {
      LayoutRawBlock* b = all_fields->at(i);
      _last->set_next_block(b);
      b->set_prev_block(_last);
      _last = b;

*** 350,22 ***
      }
      b = b->next_block();
    }
    assert(b->next_block() == NULL, "Invariant at this point");
    assert(b->kind() != LayoutRawBlock::EMPTY, "Sanity check");
- 
    // If the super class has @Contended annotation, a padding block is
    // inserted at the end to ensure that fields from the subclasses won't share
    // the cache line of the last field of the contended class
    if (super_klass->has_contended_annotations() && ContendedPaddingWidth > 0) {
      LayoutRawBlock* p = new LayoutRawBlock(LayoutRawBlock::PADDING, ContendedPaddingWidth);
      p->set_offset(b->offset() + b->size());
      b->set_next_block(p);
      p->set_prev_block(b);
      b = p;
    }
- 
    if (!UseEmptySlotsInSupers) {
      // Add an empty slots to align fields of the subclass on a heapOopSize boundary
      // in order to emulate the behavior of the previous algorithm
      int align = (b->offset() + b->size()) % heapOopSize;
      if (align != 0) {
--- 390,20 ---

*** 375,11 ***
        b->set_next_block(p);
        p->set_prev_block(b);
        b = p;
      }
    }
- 
    LayoutRawBlock* last = new LayoutRawBlock(LayoutRawBlock::EMPTY, INT_MAX);
    last->set_offset(b->offset() + b->size());
    assert(last->offset() > 0, "Sanity check");
    b->set_next_block(last);
    last->set_prev_block(b);
--- 413,10 ---

*** 427,96 ***
  void FieldLayout::print(outputStream* output, bool is_static, const InstanceKlass* super) {
    ResourceMark rm;
    LayoutRawBlock* b = _blocks;
    while(b != _last) {
      switch(b->kind()) {
!       case LayoutRawBlock::REGULAR: {
!         FieldInfo* fi = FieldInfo::from_field_array(_fields, b->field_index());
!         output->print_cr(" @%d \"%s\" %s %d/%d %s",
!                          b->offset(),
!                          fi->name(_cp)->as_C_string(),
!                          fi->signature(_cp)->as_C_string(),
!                          b->size(),
!                          b->alignment(),
!                          "REGULAR");
!         break;
!       }
!       case LayoutRawBlock::FLATTENED: {
!         FieldInfo* fi = FieldInfo::from_field_array(_fields, b->field_index());
!         output->print_cr(" @%d \"%s\" %s %d/%d %s",
!                          b->offset(),
!                          fi->name(_cp)->as_C_string(),
!                          fi->signature(_cp)->as_C_string(),
!                          b->size(),
!                          b->alignment(),
!                          "FLATTENED");
!         break;
!       }
!       case LayoutRawBlock::RESERVED: {
!         output->print_cr(" @%d %d/- %s",
!                          b->offset(),
!                          b->size(),
!                          "RESERVED");
!         break;
!       }
!       case LayoutRawBlock::INHERITED: {
!         assert(!is_static, "Static fields are not inherited in layouts");
!         assert(super != NULL, "super klass must be provided to retrieve inherited fields info");
!         bool found = false;
!         const InstanceKlass* ik = super;
!         while (!found && ik != NULL) {
!           for (AllFieldStream fs(ik->fields(), ik->constants()); !fs.done(); fs.next()) {
!             if (fs.offset() == b->offset()) {
!               output->print_cr(" @%d \"%s\" %s %d/%d %s",
!                   b->offset(),
!                   fs.name()->as_C_string(),
!                   fs.signature()->as_C_string(),
!                   b->size(),
!                   b->size(), // so far, alignment constraint == size, will change with Valhalla
!                   "INHERITED");
!               found = true;
!               break;
-             }
            }
-           ik = ik->java_super();
          }
!         break;
        }
!       case LayoutRawBlock::EMPTY:
!         output->print_cr(" @%d %d/1 %s",
!                          b->offset(),
!                          b->size(),
!                         "EMPTY");
!         break;
!       case LayoutRawBlock::PADDING:
!         output->print_cr(" @%d %d/1 %s",
!                          b->offset(),
!                          b->size(),
!                         "PADDING");
!         break;
      }
      b = b->next_block();
    }
  }
  
  FieldLayoutBuilder::FieldLayoutBuilder(const Symbol* classname, const InstanceKlass* super_klass, ConstantPool* constant_pool,
!       Array<u2>* fields, bool is_contended, FieldLayoutInfo* info) :
    _classname(classname),
    _super_klass(super_klass),
    _constant_pool(constant_pool),
    _fields(fields),
    _info(info),
    _root_group(NULL),
    _contended_groups(GrowableArray<FieldGroup*>(8)),
    _static_fields(NULL),
    _layout(NULL),
    _static_layout(NULL),
    _nonstatic_oopmap_count(0),
    _alignment(-1),
    _has_nonstatic_fields(false),
!   _is_contended(is_contended) {}
! 
  
  FieldGroup* FieldLayoutBuilder::get_or_create_contended_group(int g) {
    assert(g > 0, "must only be called for named contended groups");
    FieldGroup* fg = NULL;
    for (int i = 0; i < _contended_groups.length(); i++) {
--- 464,106 ---
  void FieldLayout::print(outputStream* output, bool is_static, const InstanceKlass* super) {
    ResourceMark rm;
    LayoutRawBlock* b = _blocks;
    while(b != _last) {
      switch(b->kind()) {
!     case LayoutRawBlock::REGULAR: {
!       FieldInfo* fi = FieldInfo::from_field_array(_fields, b->field_index());
!       output->print_cr(" @%d \"%s\" %s %d/%d %s",
!                        b->offset(),
!                        fi->name(_cp)->as_C_string(),
!                        fi->signature(_cp)->as_C_string(),
!                        b->size(),
!                        b->alignment(),
!                        "REGULAR");
!       break;
!     }
!     case LayoutRawBlock::INLINED: {
!       FieldInfo* fi = FieldInfo::from_field_array(_fields, b->field_index());
!       output->print_cr(" @%d \"%s\" %s %d/%d %s",
!                        b->offset(),
!                        fi->name(_cp)->as_C_string(),
!                        fi->signature(_cp)->as_C_string(),
!                        b->size(),
!                        b->alignment(),
!                        "INLINED");
!       break;
!     }
!     case LayoutRawBlock::RESERVED: {
!       output->print_cr(" @%d %d/- %s",
!                        b->offset(),
!                        b->size(),
!                        "RESERVED");
!       break;
!     }
!     case LayoutRawBlock::INHERITED: {
!       assert(!is_static, "Static fields are not inherited in layouts");
!       assert(super != NULL, "super klass must be provided to retrieve inherited fields info");
!       bool found = false;
!       const InstanceKlass* ik = super;
!       while (!found && ik != NULL) {
!         for (AllFieldStream fs(ik->fields(), ik->constants()); !fs.done(); fs.next()) {
!           if (fs.offset() == b->offset()) {
!             output->print_cr(" @%d \"%s\" %s %d/%d %s",
!                 b->offset(),
!                 fs.name()->as_C_string(),
!                 fs.signature()->as_C_string(),
!                 b->size(),
!                 b->size(), // so far, alignment constraint == size, will change with Valhalla
!                 "INHERITED");
!             found = true;
!             break;
            }
          }
!         ik = ik->java_super();
        }
!       break;
!     }
!     case LayoutRawBlock::EMPTY:
!       output->print_cr(" @%d %d/1 %s",
!                        b->offset(),
!                        b->size(),
!                        "EMPTY");
!       break;
!     case LayoutRawBlock::PADDING:
!       output->print_cr(" @%d %d/1 %s",
!                        b->offset(),
!                        b->size(),
+                        "PADDING");
+       break;
      }
      b = b->next_block();
    }
  }
  
  FieldLayoutBuilder::FieldLayoutBuilder(const Symbol* classname, const InstanceKlass* super_klass, ConstantPool* constant_pool,
!                                        Array<u2>* fields, bool is_contended, bool is_inline_type, ClassLoaderData* class_loader_data,
+                                        Handle protection_domain, FieldLayoutInfo* info) :
    _classname(classname),
    _super_klass(super_klass),
    _constant_pool(constant_pool),
    _fields(fields),
    _info(info),
    _root_group(NULL),
    _contended_groups(GrowableArray<FieldGroup*>(8)),
    _static_fields(NULL),
    _layout(NULL),
    _static_layout(NULL),
+   _class_loader_data(class_loader_data),
+   _protection_domain(protection_domain),
    _nonstatic_oopmap_count(0),
    _alignment(-1),
+   _first_field_offset(-1),
+   _exact_size_in_bytes(-1),
    _has_nonstatic_fields(false),
!   _has_inline_type_fields(false),
!   _is_contended(is_contended),
+   _is_inline_type(is_inline_type),
+   _has_flattening_information(is_inline_type),
+   _has_nonatomic_values(false),
+   _atomic_field_count(0)
+  {}
  
  FieldGroup* FieldLayoutBuilder::get_or_create_contended_group(int g) {
    assert(g > 0, "must only be called for named contended groups");
    FieldGroup* fg = NULL;
    for (int i = 0; i < _contended_groups.length(); i++) {

*** 539,22 ***
    _static_layout->initialize_static_layout();
    _static_fields = new FieldGroup();
    _root_group = new FieldGroup();
  }
  
! // Field sorting for regular classes:
  //   - fields are sorted in static and non-static fields
  //   - non-static fields are also sorted according to their contention group
  //     (support of the @Contended annotation)
  //   - @Contended annotation is ignored for static fields
  void FieldLayoutBuilder::regular_field_sorting() {
    for (AllFieldStream fs(_fields, _constant_pool); !fs.done(); fs.next()) {
      FieldGroup* group = NULL;
      if (fs.access_flags().is_static()) {
        group = _static_fields;
      } else {
        _has_nonstatic_fields = true;
        if (fs.is_contended()) {
          int g = fs.contended_group();
          if (g == 0) {
            group = new FieldGroup(true);
            _contended_groups.append(group);
--- 586,24 ---
    _static_layout->initialize_static_layout();
    _static_fields = new FieldGroup();
    _root_group = new FieldGroup();
  }
  
! // Field sorting for regular (non-inline) classes:
  //   - fields are sorted in static and non-static fields
  //   - non-static fields are also sorted according to their contention group
  //     (support of the @Contended annotation)
  //   - @Contended annotation is ignored for static fields
+ //   - field flattening decisions are taken in this method
  void FieldLayoutBuilder::regular_field_sorting() {
    for (AllFieldStream fs(_fields, _constant_pool); !fs.done(); fs.next()) {
      FieldGroup* group = NULL;
      if (fs.access_flags().is_static()) {
        group = _static_fields;
      } else {
        _has_nonstatic_fields = true;
+       _atomic_field_count++;  // we might decrement this
        if (fs.is_contended()) {
          int g = fs.contended_group();
          if (g == 0) {
            group = new FieldGroup(true);
            _contended_groups.append(group);

*** 566,27 ***
        }
      }
      assert(group != NULL, "invariant");
      BasicType type = Signature::basic_type(fs.signature());
      switch(type) {
!       case T_BYTE:
!       case T_CHAR:
!       case T_DOUBLE:
!       case T_FLOAT:
!       case T_INT:
!       case T_LONG:
!       case T_SHORT:
!       case T_BOOLEAN:
!         group->add_primitive_field(fs, type);
!         break;
!       case T_OBJECT:
!       case T_ARRAY:
!         if (group != _static_fields) _nonstatic_oopmap_count++;
          group->add_oop_field(fs);
!         break;
!       default:
!         fatal("Something wrong?");
      }
    }
    _root_group->sort_by_size();
    _static_fields->sort_by_size();
    if (!_contended_groups.is_empty()) {
--- 615,67 ---
        }
      }
      assert(group != NULL, "invariant");
      BasicType type = Signature::basic_type(fs.signature());
      switch(type) {
!     case T_BYTE:
!     case T_CHAR:
!     case T_DOUBLE:
!     case T_FLOAT:
!     case T_INT:
!     case T_LONG:
!     case T_SHORT:
!     case T_BOOLEAN:
!       group->add_primitive_field(fs, type);
!       break;
!     case T_OBJECT:
!     case T_ARRAY:
!       if (group != _static_fields) _nonstatic_oopmap_count++;
+       group->add_oop_field(fs);
+       break;
+     case T_INLINE_TYPE:
+       _has_inline_type_fields = true;
+       if (group == _static_fields) {
+         // static fields are never inlined
          group->add_oop_field(fs);
!       } else {
!         _has_flattening_information = true;
!         // Flattening decision to be taken here
+         // This code assumes all verification already have been performed
+         // (field's type has been loaded and it is an inline klass)
+         JavaThread* THREAD = JavaThread::current();
+         Klass* klass =
+             SystemDictionary::resolve_inline_type_field_or_fail(&fs,
+                                                                 Handle(THREAD, _class_loader_data->class_loader()),
+                                                                 _protection_domain, true, THREAD);
+         assert(klass != NULL, "Sanity check");
+         InlineKlass* vk = InlineKlass::cast(klass);
+         bool too_big_to_flatten = (InlineFieldMaxFlatSize >= 0 &&
+                                    (vk->size_helper() * HeapWordSize) > InlineFieldMaxFlatSize);
+         bool too_atomic_to_flatten = vk->is_declared_atomic() || AlwaysAtomicAccesses;
+         bool too_volatile_to_flatten = fs.access_flags().is_volatile();
+         if (vk->is_naturally_atomic()) {
+           too_atomic_to_flatten = false;
+           //too_volatile_to_flatten = false; //FIXME
+           // volatile fields are currently never inlined, this could change in the future
+         }
+         if (!(too_big_to_flatten | too_atomic_to_flatten | too_volatile_to_flatten) || fs.access_flags().is_final()) {
+           group->add_inlined_field(fs, vk);
+           _nonstatic_oopmap_count += vk->nonstatic_oop_map_count();
+           fs.set_inlined(true);
+           if (!vk->is_atomic()) {  // flat and non-atomic: take note
+             _has_nonatomic_values = true;
+             _atomic_field_count--;  // every other field is atomic but this one
+           }
+         } else {
+           _nonstatic_oopmap_count++;
+           group->add_oop_field(fs);
+         }
+       }
+       break;
+     default:
+       fatal("Something wrong?");
      }
    }
    _root_group->sort_by_size();
    _static_fields->sort_by_size();
    if (!_contended_groups.is_empty()) {

*** 594,87 ***
        _contended_groups.at(i)->sort_by_size();
      }
    }
  }
  
  void FieldLayoutBuilder::insert_contended_padding(LayoutRawBlock* slot) {
    if (ContendedPaddingWidth > 0) {
      LayoutRawBlock* padding = new LayoutRawBlock(LayoutRawBlock::PADDING, ContendedPaddingWidth);
      _layout->insert(slot, padding);
    }
  }
  
! // Computation of regular classes layout is an evolution of the previous default layout
! // (FieldAllocationStyle 1):
! //   - primitive fields are allocated first (from the biggest to the smallest)
! //   - then oop fields are allocated, either in existing gaps or at the end of
! //     the layout
  void FieldLayoutBuilder::compute_regular_layout() {
    bool need_tail_padding = false;
    prologue();
    regular_field_sorting();
- 
    if (_is_contended) {
      _layout->set_start(_layout->last_block());
      // insertion is currently easy because the current strategy doesn't try to fill holes
      // in super classes layouts => the _start block is by consequence the _last_block
      insert_contended_padding(_layout->start());
      need_tail_padding = true;
    }
!   _layout->add(_root_group->primitive_fields());
    _layout->add(_root_group->oop_fields());
  
    if (!_contended_groups.is_empty()) {
      for (int i = 0; i < _contended_groups.length(); i++) {
        FieldGroup* cg = _contended_groups.at(i);
        LayoutRawBlock* start = _layout->last_block();
        insert_contended_padding(start);
!       _layout->add(cg->primitive_fields(), start);
        _layout->add(cg->oop_fields(), start);
        need_tail_padding = true;
      }
    }
  
    if (need_tail_padding) {
      insert_contended_padding(_layout->last_block());
    }
  
!   _static_layout->add_contiguously(this->_static_fields->oop_fields());
!   _static_layout->add(this->_static_fields->primitive_fields());
  
    epilogue();
  }
  
  void FieldLayoutBuilder::epilogue() {
    // Computing oopmaps
    int super_oop_map_count = (_super_klass == NULL) ? 0 :_super_klass->nonstatic_oop_map_count();
    int max_oop_map_count = super_oop_map_count + _nonstatic_oopmap_count;
- 
    OopMapBlocksBuilder* nonstatic_oop_maps =
        new OopMapBlocksBuilder(max_oop_map_count);
    if (super_oop_map_count > 0) {
      nonstatic_oop_maps->initialize_inherited_blocks(_super_klass->start_of_nonstatic_oop_maps(),
      _super_klass->nonstatic_oop_map_count());
    }
! 
-   if (_root_group->oop_fields() != NULL) {
-     for (int i = 0; i < _root_group->oop_fields()->length(); i++) {
-       LayoutRawBlock* b = _root_group->oop_fields()->at(i);
-       nonstatic_oop_maps->add(b->offset(), 1);
-     }
-   }
- 
    if (!_contended_groups.is_empty()) {
      for (int i = 0; i < _contended_groups.length(); i++) {
        FieldGroup* cg = _contended_groups.at(i);
        if (cg->oop_count() > 0) {
          assert(cg->oop_fields() != NULL && cg->oop_fields()->at(0) != NULL, "oop_count > 0 but no oop fields found");
!         nonstatic_oop_maps->add(cg->oop_fields()->at(0)->offset(), cg->oop_count());
        }
      }
    }
- 
    nonstatic_oop_maps->compact();
  
    int instance_end = align_up(_layout->last_block()->offset(), wordSize);
    int static_fields_end = align_up(_static_layout->last_block()->offset(), wordSize);
    int static_fields_size = (static_fields_end -
--- 683,275 ---
        _contended_groups.at(i)->sort_by_size();
      }
    }
  }
  
+ /* Field sorting for inline classes:
+  *   - because inline classes are immutable, the @Contended annotation is ignored
+  *     when computing their layout (with only read operation, there's no false
+  *     sharing issue)
+  *   - this method also records the alignment of the field with the most
+  *     constraining alignment, this value is then used as the alignment
+  *     constraint when flattening this inline type into another container
+  *   - field flattening decisions are taken in this method (those decisions are
+  *     currently only based in the size of the fields to be inlined, the size
+  *     of the resulting instance is not considered)
+  */
+ void FieldLayoutBuilder::inline_class_field_sorting(TRAPS) {
+   assert(_is_inline_type, "Should only be used for inline classes");
+   int alignment = 1;
+   for (AllFieldStream fs(_fields, _constant_pool); !fs.done(); fs.next()) {
+     FieldGroup* group = NULL;
+     int field_alignment = 1;
+     if (fs.access_flags().is_static()) {
+       group = _static_fields;
+     } else {
+       _has_nonstatic_fields = true;
+       _atomic_field_count++;  // we might decrement this
+       group = _root_group;
+     }
+     assert(group != NULL, "invariant");
+     BasicType type = Signature::basic_type(fs.signature());
+     switch(type) {
+     case T_BYTE:
+     case T_CHAR:
+     case T_DOUBLE:
+     case T_FLOAT:
+     case T_INT:
+     case T_LONG:
+     case T_SHORT:
+     case T_BOOLEAN:
+       if (group != _static_fields) {
+         field_alignment = type2aelembytes(type); // alignment == size for primitive types
+       }
+       group->add_primitive_field(fs, type);
+       break;
+     case T_OBJECT:
+     case T_ARRAY:
+       if (group != _static_fields) {
+         _nonstatic_oopmap_count++;
+         field_alignment = type2aelembytes(type); // alignment == size for oops
+       }
+       group->add_oop_field(fs);
+       break;
+     case T_INLINE_TYPE: {
+ //      fs.set_inline(true);
+       _has_inline_type_fields = true;
+       if (group == _static_fields) {
+         // static fields are never inlined
+         group->add_oop_field(fs);
+       } else {
+         // Flattening decision to be taken here
+         // This code assumes all verifications have already been performed
+         // (field's type has been loaded and it is an inline klass)
+         JavaThread* THREAD = JavaThread::current();
+         Klass* klass =
+             SystemDictionary::resolve_inline_type_field_or_fail(&fs,
+                 Handle(THREAD, _class_loader_data->class_loader()),
+                 _protection_domain, true, CHECK);
+         assert(klass != NULL, "Sanity check");
+         InlineKlass* vk = InlineKlass::cast(klass);
+         bool too_big_to_flatten = (InlineFieldMaxFlatSize >= 0 &&
+                                    (vk->size_helper() * HeapWordSize) > InlineFieldMaxFlatSize);
+         bool too_atomic_to_flatten = vk->is_declared_atomic() || AlwaysAtomicAccesses;
+         bool too_volatile_to_flatten = fs.access_flags().is_volatile();
+         if (vk->is_naturally_atomic()) {
+           too_atomic_to_flatten = false;
+           //too_volatile_to_flatten = false; //FIXME
+           // volatile fields are currently never inlined, this could change in the future
+         }
+         if (!(too_big_to_flatten | too_atomic_to_flatten | too_volatile_to_flatten) || fs.access_flags().is_final()) {
+           group->add_inlined_field(fs, vk);
+           _nonstatic_oopmap_count += vk->nonstatic_oop_map_count();
+           field_alignment = vk->get_alignment();
+           fs.set_inlined(true);
+           if (!vk->is_atomic()) {  // flat and non-atomic: take note
+             _has_nonatomic_values = true;
+             _atomic_field_count--;  // every other field is atomic but this one
+           }
+         } else {
+           _nonstatic_oopmap_count++;
+           field_alignment = type2aelembytes(T_OBJECT);
+           group->add_oop_field(fs);
+         }
+       }
+       break;
+     }
+     default:
+       fatal("Unexpected BasicType");
+     }
+     if (!fs.access_flags().is_static() && field_alignment > alignment) alignment = field_alignment;
+   }
+   _alignment = alignment;
+   if (!_has_nonstatic_fields) {
+     // There are a number of fixes required throughout the type system and JIT
+     Exceptions::fthrow(THREAD_AND_LOCATION,
+                        vmSymbols::java_lang_ClassFormatError(),
+                        "Value Types do not support zero instance size yet");
+     return;
+   }
+ }
+ 
  void FieldLayoutBuilder::insert_contended_padding(LayoutRawBlock* slot) {
    if (ContendedPaddingWidth > 0) {
      LayoutRawBlock* padding = new LayoutRawBlock(LayoutRawBlock::PADDING, ContendedPaddingWidth);
      _layout->insert(slot, padding);
    }
  }
  
! /* Computation of regular classes layout is an evolution of the previous default layout
!  * (FieldAllocationStyle 1):
!  *   - primitive fields (both primitive types and flattened inline types) are allocated
!  *     first, from the biggest to the smallest
!  *   - then oop fields are allocated (to increase chances to have contiguous oops and
+  *     a simpler oopmap).
+  */
  void FieldLayoutBuilder::compute_regular_layout() {
    bool need_tail_padding = false;
    prologue();
    regular_field_sorting();
    if (_is_contended) {
      _layout->set_start(_layout->last_block());
      // insertion is currently easy because the current strategy doesn't try to fill holes
      // in super classes layouts => the _start block is by consequence the _last_block
      insert_contended_padding(_layout->start());
      need_tail_padding = true;
    }
!   _layout->add(_root_group->big_primitive_fields());
+   _layout->add(_root_group->small_primitive_fields());
    _layout->add(_root_group->oop_fields());
  
    if (!_contended_groups.is_empty()) {
      for (int i = 0; i < _contended_groups.length(); i++) {
        FieldGroup* cg = _contended_groups.at(i);
        LayoutRawBlock* start = _layout->last_block();
        insert_contended_padding(start);
!       _layout->add(cg->big_primitive_fields());
+       _layout->add(cg->small_primitive_fields(), start);
        _layout->add(cg->oop_fields(), start);
        need_tail_padding = true;
      }
    }
  
    if (need_tail_padding) {
      insert_contended_padding(_layout->last_block());
    }
+   // Warning: IntanceMirrorKlass expects static oops to be allocated first
+   _static_layout->add_contiguously(_static_fields->oop_fields());
+   _static_layout->add(_static_fields->big_primitive_fields());
+   _static_layout->add(_static_fields->small_primitive_fields());
  
!   epilogue();
! }
+ 
+ /* Computation of inline classes has a slightly different strategy than for
+  * regular classes. Regular classes have their oop fields allocated at the end
+  * of the layout to increase GC performances. Unfortunately, this strategy
+  * increases the number of empty slots inside an instance. Because the purpose
+  * of inline classes is to be embedded into other containers, it is critical
+  * to keep their size as small as possible. For this reason, the allocation
+  * strategy is:
+  *   - big primitive fields (primitive types and flattened inline type smaller
+  *     than an oop) are allocated first (from the biggest to the smallest)
+  *   - then oop fields
+  *   - then small primitive fields (from the biggest to the smallest)
+  */
+ void FieldLayoutBuilder::compute_inline_class_layout(TRAPS) {
+   prologue();
+   inline_class_field_sorting(CHECK);
+   // Inline types are not polymorphic, so they cannot inherit fields.
+   // By consequence, at this stage, the layout must be composed of a RESERVED
+   // block, followed by an EMPTY block.
+   assert(_layout->start()->kind() == LayoutRawBlock::RESERVED, "Unexpected");
+   assert(_layout->start()->next_block()->kind() == LayoutRawBlock::EMPTY, "Unexpected");
+   LayoutRawBlock* first_empty = _layout->start()->next_block();
+   if (first_empty->offset() % _alignment != 0) {
+     LayoutRawBlock* padding = new LayoutRawBlock(LayoutRawBlock::PADDING, _alignment - (first_empty->offset() % _alignment));
+     _layout->insert(first_empty, padding);
+     _layout->set_start(padding->next_block());
+   }
+ 
+   _layout->add(_root_group->big_primitive_fields());
+   _layout->add(_root_group->oop_fields());
+   _layout->add(_root_group->small_primitive_fields());
+ 
+   LayoutRawBlock* first_field = _layout->first_field_block();
+    if (first_field != NULL) {
+      _first_field_offset = _layout->first_field_block()->offset();
+      _exact_size_in_bytes = _layout->last_block()->offset() - _layout->first_field_block()->offset();
+    } else {
+      // special case for empty value types
+      _first_field_offset = _layout->blocks()->size();
+      _exact_size_in_bytes = 0;
+    }
+   _exact_size_in_bytes = _layout->last_block()->offset() - _layout->first_field_block()->offset();
+ 
+   // Warning:: InstanceMirrorKlass expects static oops to be allocated first
+   _static_layout->add_contiguously(_static_fields->oop_fields());
+   _static_layout->add(_static_fields->big_primitive_fields());
+   _static_layout->add(_static_fields->small_primitive_fields());
  
    epilogue();
  }
  
+ void FieldLayoutBuilder::add_inlined_field_oopmap(OopMapBlocksBuilder* nonstatic_oop_maps,
+                 InlineKlass* vklass, int offset) {
+   int diff = offset - vklass->first_field_offset();
+   const OopMapBlock* map = vklass->start_of_nonstatic_oop_maps();
+   const OopMapBlock* last_map = map + vklass->nonstatic_oop_map_count();
+   while (map < last_map) {
+     nonstatic_oop_maps->add(map->offset() + diff, map->count());
+     map++;
+   }
+ }
+ 
+ void FieldLayoutBuilder::register_embedded_oops_from_list(OopMapBlocksBuilder* nonstatic_oop_maps, GrowableArray<LayoutRawBlock*>* list) {
+   if (list != NULL) {
+     for (int i = 0; i < list->length(); i++) {
+       LayoutRawBlock* f = list->at(i);
+       if (f->kind() == LayoutRawBlock::INLINED) {
+         InlineKlass* vk = f->inline_klass();
+         assert(vk != NULL, "Should have been initialized");
+         if (vk->contains_oops()) {
+           add_inlined_field_oopmap(nonstatic_oop_maps, vk, f->offset());
+         }
+       }
+     }
+   }
+ }
+ 
+ void FieldLayoutBuilder::register_embedded_oops(OopMapBlocksBuilder* nonstatic_oop_maps, FieldGroup* group) {
+   if (group->oop_fields() != NULL) {
+     for (int i = 0; i < group->oop_fields()->length(); i++) {
+       LayoutRawBlock* b = group->oop_fields()->at(i);
+       nonstatic_oop_maps->add(b->offset(), 1);
+     }
+   }
+   register_embedded_oops_from_list(nonstatic_oop_maps, group->big_primitive_fields());
+   register_embedded_oops_from_list(nonstatic_oop_maps, group->small_primitive_fields());
+ }
+ 
  void FieldLayoutBuilder::epilogue() {
    // Computing oopmaps
    int super_oop_map_count = (_super_klass == NULL) ? 0 :_super_klass->nonstatic_oop_map_count();
    int max_oop_map_count = super_oop_map_count + _nonstatic_oopmap_count;
    OopMapBlocksBuilder* nonstatic_oop_maps =
        new OopMapBlocksBuilder(max_oop_map_count);
    if (super_oop_map_count > 0) {
      nonstatic_oop_maps->initialize_inherited_blocks(_super_klass->start_of_nonstatic_oop_maps(),
      _super_klass->nonstatic_oop_map_count());
    }
!   register_embedded_oops(nonstatic_oop_maps, _root_group);
    if (!_contended_groups.is_empty()) {
      for (int i = 0; i < _contended_groups.length(); i++) {
        FieldGroup* cg = _contended_groups.at(i);
        if (cg->oop_count() > 0) {
          assert(cg->oop_fields() != NULL && cg->oop_fields()->at(0) != NULL, "oop_count > 0 but no oop fields found");
!         register_embedded_oops(nonstatic_oop_maps, cg);
        }
      }
    }
    nonstatic_oop_maps->compact();
  
    int instance_end = align_up(_layout->last_block()->offset(), wordSize);
    int static_fields_end = align_up(_static_layout->last_block()->offset(), wordSize);
    int static_fields_size = (static_fields_end -

*** 686,21 ***
    _info->oop_map_blocks = nonstatic_oop_maps;
    _info->_instance_size = align_object_size(instance_end / wordSize);
    _info->_static_field_size = static_fields_size;
    _info->_nonstatic_field_size = (nonstatic_field_end - instanceOopDesc::base_offset_in_bytes()) / heapOopSize;
    _info->_has_nonstatic_fields = _has_nonstatic_fields;
! 
!   if (PrintFieldLayout) {
      ResourceMark rm;
      tty->print_cr("Layout of class %s", _classname->as_C_string());
      tty->print_cr("Instance fields:");
      _layout->print(tty, false, _super_klass);
      tty->print_cr("Static fields:");
      _static_layout->print(tty, true, NULL);
      tty->print_cr("Instance size = %d bytes", _info->_instance_size * wordSize);
      tty->print_cr("---");
    }
  }
  
! void FieldLayoutBuilder::build_layout() {
!   compute_regular_layout();
  }
--- 963,44 ---
    _info->oop_map_blocks = nonstatic_oop_maps;
    _info->_instance_size = align_object_size(instance_end / wordSize);
    _info->_static_field_size = static_fields_size;
    _info->_nonstatic_field_size = (nonstatic_field_end - instanceOopDesc::base_offset_in_bytes()) / heapOopSize;
    _info->_has_nonstatic_fields = _has_nonstatic_fields;
!   _info->_has_inline_fields = _has_inline_type_fields;
! 
+   // An inline type is naturally atomic if it has just one field, and
+   // that field is simple enough.
+   _info->_is_naturally_atomic = (_is_inline_type &&
+                                  (_atomic_field_count <= 1) &&
+                                  !_has_nonatomic_values &&
+                                  _contended_groups.is_empty());
+   // This may be too restrictive, since if all the fields fit in 64
+   // bits we could make the decision to align instances of this class
+   // to 64-bit boundaries, and load and store them as single words.
+   // And on machines which supported larger atomics we could similarly
+   // allow larger values to be atomic, if properly aligned.
+ 
+ 
+   if (PrintFieldLayout || (PrintInlineLayout && _has_flattening_information)) {
      ResourceMark rm;
      tty->print_cr("Layout of class %s", _classname->as_C_string());
      tty->print_cr("Instance fields:");
      _layout->print(tty, false, _super_klass);
      tty->print_cr("Static fields:");
      _static_layout->print(tty, true, NULL);
      tty->print_cr("Instance size = %d bytes", _info->_instance_size * wordSize);
+     if (_is_inline_type) {
+       tty->print_cr("First field offset = %d", _first_field_offset);
+       tty->print_cr("Alignment = %d bytes", _alignment);
+       tty->print_cr("Exact size = %d bytes", _exact_size_in_bytes);
+     }
      tty->print_cr("---");
    }
  }
  
! void FieldLayoutBuilder::build_layout(TRAPS) {
!   if (_is_inline_type) {
+     compute_inline_class_layout(CHECK);
+   } else {
+     compute_regular_layout();
+   }
  }
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