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*/
#include "precompiled.hpp"
#include "classfile/classFileParser.hpp"
#include "classfile/fieldLayoutBuilder.hpp"
+ #include "classfile/systemDictionary.hpp"
+ #include "classfile/vmSymbols.hpp"
#include "jvm.h"
#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(nullptr),
_prev_block(nullptr),
+ _inline_klass(nullptr),
_kind(kind),
_offset(-1),
_alignment(1),
_size(size),
_field_index(-1),
LayoutRawBlock::LayoutRawBlock(int index, Kind kind, int size, int alignment, bool is_reference) :
_next_block(nullptr),
_prev_block(nullptr),
+ _inline_klass(nullptr),
_kind(kind),
_offset(-1),
_alignment(alignment),
_size(size),
_field_index(index),
_is_reference(is_reference) {
- assert(kind == REGULAR || kind == FLATTENED || kind == INHERITED,
+ assert(kind == REGULAR || kind == FLAT || kind == INHERITED,
"Other kind do not have a field index");
assert(size > 0, "Sanity check");
assert(alignment > 0, "Sanity check");
}
return _size >= size + adjustment;
}
FieldGroup::FieldGroup(int contended_group) :
_next(nullptr),
- _primitive_fields(nullptr),
+ _small_primitive_fields(nullptr),
+ _big_primitive_fields(nullptr),
_oop_fields(nullptr),
_contended_group(contended_group), // -1 means no contended group, 0 means default contended group
_oop_count(0) {}
void FieldGroup::add_primitive_field(int idx, BasicType type) {
int size = type2aelembytes(type);
LayoutRawBlock* block = new LayoutRawBlock(idx, LayoutRawBlock::REGULAR, size, size /* alignment == size for primitive types */, false);
- if (_primitive_fields == nullptr) {
- _primitive_fields = new GrowableArray<LayoutRawBlock*>(INITIAL_LIST_SIZE);
+ if (size >= oopSize) {
+ add_to_big_primitive_list(block);
+ } else {
+ add_to_small_primitive_list(block);
}
- _primitive_fields->append(block);
}
void FieldGroup::add_oop_field(int idx) {
int size = type2aelembytes(T_OBJECT);
LayoutRawBlock* block = new LayoutRawBlock(idx, LayoutRawBlock::REGULAR, size, size /* alignment == size for oops */, true);
}
_oop_fields->append(block);
_oop_count++;
}
+ void FieldGroup::add_flat_field(int idx, InlineKlass* vk) {
+ LayoutRawBlock* block = new LayoutRawBlock(idx, LayoutRawBlock::FLAT, 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 (_primitive_fields != nullptr) {
- _primitive_fields->sort(LayoutRawBlock::compare_size_inverted);
+ if (_small_primitive_fields != nullptr) {
+ _small_primitive_fields->sort(LayoutRawBlock::compare_size_inverted);
+ }
+ if (_big_primitive_fields != nullptr) {
+ _big_primitive_fields->sort(LayoutRawBlock::compare_size_inverted);
+ }
+ }
+
+ void FieldGroup::add_to_small_primitive_list(LayoutRawBlock* block) {
+ if (_small_primitive_fields == nullptr) {
+ _small_primitive_fields = new GrowableArray<LayoutRawBlock*>(INITIAL_LIST_SIZE);
+ }
+ _small_primitive_fields->append(block);
+ }
+
+ void FieldGroup::add_to_big_primitive_list(LayoutRawBlock* block) {
+ if (_big_primitive_fields == nullptr) {
+ _big_primitive_fields = new GrowableArray<LayoutRawBlock*>(INITIAL_LIST_SIZE);
}
+ _big_primitive_fields->append(block);
}
FieldLayout::FieldLayout(GrowableArray<FieldInfo>* field_info, ConstantPool* cp) :
_field_info(field_info),
_cp(cp),
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
+ _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 = _start;
- while (block->kind() != LayoutRawBlock::INHERITED && block->kind() != LayoutRawBlock::REGULAR
- && block->kind() != LayoutRawBlock::FLATTENED && block->kind() != LayoutRawBlock::PADDING) {
+ LayoutRawBlock* block = _blocks;
+ while (block != nullptr
+ && block->kind() != LayoutRawBlock::INHERITED
+ && block->kind() != LayoutRawBlock::REGULAR
+ && block->kind() != LayoutRawBlock::FLAT) {
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
+ // 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 == nullptr) return;
int last_alignment = 0;
for (int i = 0; i < list->length(); i ++) {
LayoutRawBlock* b = list->at(i);
LayoutRawBlock* cursor = nullptr;
LayoutRawBlock* candidate = nullptr;
-
// 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,
last_size = b->size();
last_alignment = b->alignment();
cursor = last_block()->prev_block();
assert(cursor != nullptr, "Sanity check");
last_search_success = true;
+
while (cursor != start) {
if (cursor->kind() == LayoutRawBlock::EMPTY && cursor->fit(b->size(), b->alignment())) {
if (candidate == nullptr || cursor->size() < candidate->size()) {
candidate = cursor;
}
}
assert(candidate != nullptr, "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 */
for (AllFieldStream fs(ik->fieldinfo_stream(), 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);
+ LayoutRawBlock* block;
+ if (fs.field_flags().is_null_free_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() == nullptr ? nullptr : 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;
}
b = b->next_block();
}
assert(b->next_block() == nullptr, "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) {
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);
b->size(),
b->alignment(),
"REGULAR");
break;
}
- case LayoutRawBlock::FLATTENED: {
+ case LayoutRawBlock::FLAT: {
FieldInfo* fi = _field_info->adr_at(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");
+ "FLAT");
break;
}
case LayoutRawBlock::RESERVED: {
output->print_cr(" @%d %d/- %s",
b->offset(),
b->size(), // so far, alignment constraint == size, will change with Valhalla
"INHERITED");
found = true;
break;
}
- }
- ik = ik->java_super();
}
- break;
+ ik = ik->java_super();
}
- 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;
+ 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,
- GrowableArray<FieldInfo>* field_info, bool is_contended, FieldLayoutInfo* info) :
+ GrowableArray<FieldInfo>* field_info, bool is_contended, bool is_inline_type,
+ FieldLayoutInfo* info, Array<InlineKlass*>* inline_type_field_klasses) :
_classname(classname),
_super_klass(super_klass),
_constant_pool(constant_pool),
_field_info(field_info),
_info(info),
+ _inline_type_field_klasses(inline_type_field_klasses),
_root_group(nullptr),
_contended_groups(GrowableArray<FieldGroup*>(8)),
_static_fields(nullptr),
_layout(nullptr),
_static_layout(nullptr),
_nonstatic_oopmap_count(0),
_alignment(-1),
+ _first_field_offset(-1),
+ _exact_size_in_bytes(-1),
+ _atomic_field_count(0),
+ _fields_size_sum(0),
_has_nonstatic_fields(false),
- _is_contended(is_contended) {}
-
+ _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),
+ _nullable_atomic_flat_candidate(false)
+ {}
FieldGroup* FieldLayoutBuilder::get_or_create_contended_group(int g) {
assert(g > 0, "must only be called for named contended groups");
FieldGroup* fg = nullptr;
for (int i = 0; i < _contended_groups.length(); i++) {
_static_layout->initialize_static_layout();
_static_fields = new FieldGroup();
_root_group = new FieldGroup();
}
- // Field sorting for regular classes:
+ // 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
- void FieldLayoutBuilder::regular_field_sorting() {
+ // - field flattening decisions are taken in this method
+ void FieldLayoutBuilder::regular_field_sorting(TRAPS) {
int idx = 0;
for (GrowableArrayIterator<FieldInfo> it = _field_info->begin(); it != _field_info->end(); ++it, ++idx) {
FieldInfo ctrl = _field_info->at(0);
FieldGroup* group = nullptr;
FieldInfo fieldinfo = *it;
if (fieldinfo.access_flags().is_static()) {
group = _static_fields;
} else {
_has_nonstatic_fields = true;
+ _atomic_field_count++; // we might decrement this
if (fieldinfo.field_flags().is_contended()) {
int g = fieldinfo.contended_group();
if (g == 0) {
group = new FieldGroup(true);
_contended_groups.append(group);
}
}
assert(group != nullptr, "invariant");
BasicType type = Signature::basic_type(fieldinfo.signature(_constant_pool));
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(idx, type);
- break;
- case T_OBJECT:
- case T_ARRAY:
+ 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(idx, type);
+ break;
+ case T_OBJECT:
+ case T_ARRAY:
+ if (!fieldinfo.field_flags().is_null_free_inline_type()) {
if (group != _static_fields) _nonstatic_oopmap_count++;
group->add_oop_field(idx);
- break;
- default:
- fatal("Something wrong?");
+ } else {
+ assert(type != T_ARRAY, "null free ptr to array not supported");
+ _has_inline_type_fields = true;
+ if (group == _static_fields) {
+ // static fields are never flat
+ group->add_oop_field(idx);
+ } else {
+ // Check below is performed for non-static fields, it should be performed for static fields too but at this stage,
+ // it is not guaranteed that the klass of the static field has been loaded, so the test for static fields is delayed
+ // until the linking phase
+ Klass* klass = _inline_type_field_klasses->at(idx);
+ assert(klass != nullptr, "Sanity check");
+ InlineKlass* vk = InlineKlass::cast(klass);
+ assert(vk->is_implicitly_constructible(), "must be, should have been checked in post_process_parsed_stream()");
+ _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)
+ bool too_big_to_flatten = (InlineFieldMaxFlatSize >= 0 &&
+ (vk->size_helper() * HeapWordSize) > InlineFieldMaxFlatSize);
+ bool too_atomic_to_flatten = vk->must_be_atomic() || AlwaysAtomicAccesses;
+ bool too_volatile_to_flatten = fieldinfo.access_flags().is_volatile();
+ if (vk->is_naturally_atomic()) {
+ too_atomic_to_flatten = false;
+ //too_volatile_to_flatten = false; //FIXME
+ // Currently, volatile fields are never flat, this could change in the future
+ }
+ if (!(too_big_to_flatten | too_atomic_to_flatten | too_volatile_to_flatten)) {
+ group->add_flat_field(idx, vk);
+ _nonstatic_oopmap_count += vk->nonstatic_oop_map_count();
+ _field_info->adr_at(idx)->field_flags_addr()->update_flat(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(idx);
+ }
+ }
+ }
+ break;
+ default:
+ fatal("Something wrong?");
}
}
_root_group->sort_by_size();
_static_fields->sort_by_size();
if (!_contended_groups.is_empty()) {
_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 flattened, 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 (GrowableArrayIterator<FieldInfo> it = _field_info->begin(); it != _field_info->end(); ++it) {
+ FieldGroup* group = nullptr;
+ FieldInfo fieldinfo = *it;
+ int field_alignment = 1;
+ if (fieldinfo.access_flags().is_static()) {
+ group = _static_fields;
+ } else {
+ _has_nonstatic_fields = true;
+ _atomic_field_count++; // we might decrement this
+ group = _root_group;
+ }
+ assert(group != nullptr, "invariant");
+ BasicType type = Signature::basic_type(fieldinfo.signature(_constant_pool));
+ 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(fieldinfo.index(), type);
+ break;
+ case T_OBJECT:
+ case T_ARRAY:
+ if (!fieldinfo.field_flags().is_null_free_inline_type()) {
+ if (group != _static_fields) {
+ _nonstatic_oopmap_count++;
+ field_alignment = type2aelembytes(type); // alignment == size for oops
+ }
+ group->add_oop_field(fieldinfo.index());
+ } else {
+ assert(type != T_ARRAY, "null free ptr to array not supported");
+ _has_inline_type_fields = true;
+ if (group == _static_fields) {
+ // static fields are never flat
+ group->add_oop_field(fieldinfo.index());
+ } else {
+ // Check below is performed for non-static fields, it should be performed for static fields too but at this stage,
+ // it is not guaranteed that the klass of the static field has been loaded, so the test for static fields is delayed
+ // until the linking phase
+ Klass* klass = _inline_type_field_klasses->at(fieldinfo.index());
+ assert(klass != nullptr, "Sanity check");
+ InlineKlass* vk = InlineKlass::cast(klass);
+ assert(vk->is_implicitly_constructible(), "must be, should have been checked in post_process_parsed_stream()");
+ // 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)
+ bool too_big_to_flatten = (InlineFieldMaxFlatSize >= 0 &&
+ (vk->size_helper() * HeapWordSize) > InlineFieldMaxFlatSize);
+ bool too_atomic_to_flatten = vk->must_be_atomic() || AlwaysAtomicAccesses;
+ bool too_volatile_to_flatten = fieldinfo.access_flags().is_volatile();
+ if (vk->is_naturally_atomic()) {
+ too_atomic_to_flatten = false;
+ //too_volatile_to_flatten = false; //FIXME
+ // Currently, volatile fields are never flat, this could change in the future
+ }
+ if (!(too_big_to_flatten | too_atomic_to_flatten | too_volatile_to_flatten)) {
+ group->add_flat_field(fieldinfo.index(), vk);
+ _nonstatic_oopmap_count += vk->nonstatic_oop_map_count();
+ field_alignment = vk->get_alignment();
+ _field_info->adr_at(fieldinfo.index())->field_flags_addr()->update_flat(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(fieldinfo.index());
+ }
+ }
+ }
+ break;
+ default:
+ fatal("Unexpected BasicType");
+ }
+ if (!fieldinfo.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 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() {
+ /* Computation of regular classes layout is an evolution of the previous default layout
+ * (FieldAllocationStyle 1):
+ * - primitive fields (both primitive types and flat 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(TRAPS) {
bool need_tail_padding = false;
prologue();
- regular_field_sorting();
-
+ regular_field_sorting(CHECK);
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->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->primitive_fields(), 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());
- _static_layout->add_contiguously(this->_static_fields->oop_fields());
- _static_layout->add(this->_static_fields->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 flat 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 != nullptr) {
+ _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_flat_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 != nullptr) {
+ for (int i = 0; i < list->length(); i++) {
+ LayoutRawBlock* f = list->at(i);
+ if (f->kind() == LayoutRawBlock::FLAT) {
+ InlineKlass* vk = f->inline_klass();
+ assert(vk != nullptr, "Should have been initialized");
+ if (vk->contains_oops()) {
+ add_flat_field_oopmap(nonstatic_oop_maps, vk, f->offset());
+ }
+ }
+ }
+ }
+ }
+
+ void FieldLayoutBuilder::register_embedded_oops(OopMapBlocksBuilder* nonstatic_oop_maps, FieldGroup* group) {
+ if (group->oop_fields() != nullptr) {
+ 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 == nullptr) ? 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() != nullptr) {
- 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);
- }
- }
-
+ 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() != nullptr && cg->oop_fields()->at(0) != nullptr, "oop_count > 0 but no oop fields found");
- nonstatic_oop_maps->add(cg->oop_fields()->at(0)->offset(), cg->oop_count());
+ 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 -
_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) {
+ _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, nullptr);
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() {
- compute_regular_layout();
+ void FieldLayoutBuilder::build_layout(TRAPS) {
+ if (_is_inline_type) {
+ compute_inline_class_layout(CHECK);
+ } else {
+ compute_regular_layout(CHECK);
+ }
}
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