oopMap.cpp

/*
 * Copyright (c) 1998, 2025, 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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 * questions.
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*/

#include"code/codeBlob.hpp"
#include"code/codeCache.hpp"
#include"code/nmethod.hpp"
#include"code/scopeDesc.hpp"
#include"compiler/oopMap.inline.hpp"
#include"gc/shared/collectedHeap.hpp"
#include"logging/log.hpp"
#include"logging/logStream.hpp"
#include"memory/allocation.inline.hpp"
#include"memory/iterator.hpp"
#include"memory/resourceArea.hpp"
#include"oops/compressedOops.hpp"
#include"runtime/atomic.hpp"
#include"runtime/frame.inline.hpp"
#include"runtime/handles.inline.hpp"
#include"runtime/signature.hpp"
#include"runtime/stackWatermarkSet.inline.hpp"
#include"utilities/align.hpp"
#include"utilities/lockFreeStack.hpp"
#ifdef COMPILER1
#include"c1/c1_Defs.hpp"
#endif
#ifdef COMPILER2
#include"opto/optoreg.hpp"
#endif
#if INCLUDE_JVMCI
#include"jvmci/jvmci_globals.hpp"
#endif

static_assert(sizeof(oop) == sizeof(intptr_t), "Derived pointer sanity check");

staticinlineintptr_tderived_pointer_value(derived_pointer p) {
returnstatic_cast<intptr_t>(p);
}

staticinline derived_pointer to_derived_pointer(intptr_t obj) {
returnstatic_cast<derived_pointer>(obj);
}

staticinlineintptr_toperator-(derived_pointer p, derived_pointer p1) {
returnderived_pointer_value(p) - derived_pointer_value(p1);
}

staticinline derived_pointer operator+(derived_pointer p, intptr_t offset) {
returnstatic_cast<derived_pointer>(derived_pointer_value(p) + offset);
}

// OopMapStream

OopMapStream::OopMapStream(const OopMap* oop_map)
 : _stream(oop_map->write_stream()->buffer()) {
 _size = oop_map->omv_count();
 _position = 0;
 _valid_omv = false;
}

OopMapStream::OopMapStream(const ImmutableOopMap* oop_map)
 : _stream(oop_map->data_addr()) {
 _size = oop_map->count();
 _position = 0;
 _valid_omv = false;
}

voidOopMapStream::find_next() {
if (_position++ < _size) {
 _omv.read_from(&_stream);
 _valid_omv = true;
return;
 }
 _valid_omv = false;
}


// OopMap

// frame_size units are stack-slots (4 bytes) NOT intptr_t; we can name odd
// slots to hold 4-byte values like ints and floats in the LP64 build.
OopMap::OopMap(int frame_size, int arg_count) {
// OopMaps are usually quite so small, so pick a small initial size
set_write_stream(newCompressedWriteStream(32));
set_omv_count(0);
 _num_oops = 0;
 _has_derived_oops = false;
 _index = -1;

#ifdef ASSERT
 _locs_length = VMRegImpl::stack2reg(0)->value() + frame_size + arg_count;
 _locs_used = NEW_RESOURCE_ARRAY(OopMapValue::oop_types, _locs_length);
for(int i = 0; i < _locs_length; i++) _locs_used[i] = OopMapValue::unused_value;
#endif
}


OopMap::OopMap(OopMap::DeepCopyToken, OopMap* source) {
// This constructor does a deep copy
// of the source OopMap.
set_write_stream(newCompressedWriteStream(source->omv_count() * 2));
set_omv_count(0);
set_offset(source->offset());
 _num_oops = source->num_oops();
 _has_derived_oops = source->has_derived_oops();
 _index = -1;

#ifdef ASSERT
 _locs_length = source->_locs_length;
 _locs_used = NEW_RESOURCE_ARRAY(OopMapValue::oop_types, _locs_length);
for(int i = 0; i < _locs_length; i++) _locs_used[i] = OopMapValue::unused_value;
#endif

// We need to copy the entries too.
for (OopMapStream oms(source); !oms.is_done(); oms.next()) {
 OopMapValue omv = oms.current();
 omv.write_on(write_stream());
increment_count();
 }
}


OopMap* OopMap::deep_copy() {
returnnewOopMap(_deep_copy_token, this);
}

voidOopMap::copy_data_to(address addr) const {
memcpy(addr, write_stream()->buffer(), write_stream()->position());
}

classOopMapSort {
private:
const OopMap* _map;
 OopMapValue* _values;
int _count;

public:
OopMapSort(const OopMap* map) : _map(map), _count(0) {
 _values = NEW_RESOURCE_ARRAY(OopMapValue, _map->omv_count());
 }

voidsort();

voidprint();

voidwrite(CompressedWriteStream* stream) {
for (int i = 0; i < _count; ++i) {
 _values[i].write_on(stream);
 }
 }

private:
intfind_derived_position(OopMapValue omv, int start) {
assert(omv.type() == OopMapValue::derived_oop_value, "");

 VMReg base = omv.content_reg();
int i = start;

for (; i < _count; ++i) {
if (base == _values[i].reg()) {

for (int n = i + 1; n < _count; ++n) {
if (_values[i].type() != OopMapValue::derived_oop_value || _values[i].content_reg() != base) {
return n;
 }

if (derived_cost(_values[i]) > derived_cost(omv)) {
return n;
 }
 }
return _count;
 }
 }

assert(false, "failed to find base");
return -1;
 }

intfind_position(OopMapValue omv, int start) {
assert(omv.type() != OopMapValue::derived_oop_value, "");

int i = start;
for (; i < _count; ++i) {
if (omv_cost(_values[i]) > omv_cost(omv)) {
return i;
 }
 }
assert(i < _map->omv_count(), "bounds check");
return i;
 }

voidinsert(OopMapValue value, int pos) {
assert(pos >= 0 && pos < _map->omv_count(), "bounds check");
assert(pos <= _count, "sanity");

if (pos < _count) {
 OopMapValue prev = _values[pos];

for (int i = pos; i < _count; ++i) {
 OopMapValue tmp = _values[i+1];
 _values[i+1] = prev;
 prev = tmp;
 }
 }
 _values[pos] = value;

 ++_count;
 }

intomv_cost(OopMapValue omv) {
assert(omv.type() == OopMapValue::oop_value || omv.type() == OopMapValue::narrowoop_value, "");
returnreg_cost(omv.reg());
 }

intreg_cost(VMReg reg) {
if (reg->is_reg()) {
return0;
 }
return reg->reg2stack() * VMRegImpl::stack_slot_size;
 }

intderived_cost(OopMapValue omv) {
returnreg_cost(omv.reg());
 }
};

voidOopMapSort::sort() {
#ifdef ASSERT
for (OopMapStream oms(_map); !oms.is_done(); oms.next()) {
 OopMapValue omv = oms.current();
assert(omv.type() == OopMapValue::oop_value || omv.type() == OopMapValue::narrowoop_value ||
 omv.type() == OopMapValue::derived_oop_value || omv.type() == OopMapValue::callee_saved_value, "");
 }
#endif

for (OopMapStream oms(_map); !oms.is_done(); oms.next()) {
if (oms.current().type() == OopMapValue::callee_saved_value) {
insert(oms.current(), _count);
 }
 }

int start = _count;
for (OopMapStream oms(_map); !oms.is_done(); oms.next()) {
 OopMapValue omv = oms.current();
if (omv.type() == OopMapValue::oop_value || omv.type() == OopMapValue::narrowoop_value) {
int pos = find_position(omv, start);
insert(omv, pos);
 }
 }

for (OopMapStream oms(_map); !oms.is_done(); oms.next()) {
 OopMapValue omv = oms.current();
if (omv.type() == OopMapValue::derived_oop_value) {
int pos = find_derived_position(omv, start);
assert(pos > 0, "");
insert(omv, pos);
 }
 }
}

voidOopMapSort::print() {
for (int i = 0; i < _count; ++i) {
 OopMapValue omv = _values[i];
if (omv.type() == OopMapValue::oop_value || omv.type() == OopMapValue::narrowoop_value) {
if (omv.reg()->is_reg()) {
 tty->print_cr("[%c][%d] -> reg (%d)", omv.type() == OopMapValue::narrowoop_value ? 'n' : 'o', i, omv.reg()->value());
 } else {
 tty->print_cr("[%c][%d] -> stack (%d)", omv.type() == OopMapValue::narrowoop_value ? 'n' : 'o', i, omv.reg()->reg2stack() * VMRegImpl::stack_slot_size);
 }
 } else {
if (omv.content_reg()->is_reg()) {
 tty->print_cr("[d][%d] -> reg (%d) stack (%d)", i, omv.content_reg()->value(), omv.reg()->reg2stack() * VMRegImpl::stack_slot_size);
 } elseif (omv.reg()->is_reg()) {
 tty->print_cr("[d][%d] -> stack (%d) reg (%d)", i, omv.content_reg()->reg2stack() * VMRegImpl::stack_slot_size, omv.reg()->value());
 } else {
int derived_offset = omv.reg()->reg2stack() * VMRegImpl::stack_slot_size;
int base_offset = omv.content_reg()->reg2stack() * VMRegImpl::stack_slot_size;
 tty->print_cr("[d][%d] -> stack (%x) stack (%x)", i, base_offset, derived_offset);
 }
 }
 }
}

voidOopMap::copy_and_sort_data_to(address addr) const {
 OopMapSort sort(this);
 sort.sort();
 CompressedWriteStream* stream = newCompressedWriteStream(_write_stream->position());
 sort.write(stream);

assert(stream->position() == write_stream()->position(), "");
memcpy(addr, stream->buffer(), stream->position());
}

intOopMap::heap_size() const {
int size = sizeof(OopMap);
int align = sizeof(void *) - 1;
 size += write_stream()->position();
// Align to a reasonable ending point
 size = ((size+align) & ~align);
return size;
}

// frame_size units are stack-slots (4 bytes) NOT intptr_t; we can name odd
// slots to hold 4-byte values like ints and floats in the LP64 build.
voidOopMap::set_xxx(VMReg reg, OopMapValue::oop_types x, VMReg optional) {

assert(reg->value() < _locs_length, "too big reg value for stack size");
assert( _locs_used[reg->value()] == OopMapValue::unused_value, "cannot insert twice" );
DEBUG_ONLY( _locs_used[reg->value()] = x; )

 OopMapValue o(reg, x, optional);
 o.write_on(write_stream());
increment_count();
if (x == OopMapValue::oop_value || x == OopMapValue::narrowoop_value) {
increment_num_oops();
 } elseif (x == OopMapValue::derived_oop_value) {
set_has_derived_oops(true);
 }
}


voidOopMap::set_oop(VMReg reg) {
set_xxx(reg, OopMapValue::oop_value, VMRegImpl::Bad());
}


voidOopMap::set_narrowoop(VMReg reg) {
set_xxx(reg, OopMapValue::narrowoop_value, VMRegImpl::Bad());
}


voidOopMap::set_callee_saved(VMReg reg, VMReg caller_machine_register ) {
set_xxx(reg, OopMapValue::callee_saved_value, caller_machine_register);
}


voidOopMap::set_derived_oop(VMReg reg, VMReg derived_from_local_register ) {
if( reg == derived_from_local_register ) {
// Actually an oop, derived shares storage with base,
set_oop(reg);
 } else {
set_xxx(reg, OopMapValue::derived_oop_value, derived_from_local_register);
 }
}

// OopMapSet

OopMapSet::OopMapSet() : _list(MinOopMapAllocation) {}

intOopMapSet::add_gc_map(int pc_offset, OopMap *map ) {
 map->set_offset(pc_offset);

#ifdef ASSERT
if(_list.length() > 0) {
 OopMap* last = _list.last();
if (last->offset() == map->offset() ) {
fatal("OopMap inserted twice");
 }
if (last->offset() > map->offset()) {
 tty->print_cr( "WARNING, maps not sorted: pc[%d]=%d, pc[%d]=%d",
 _list.length(),last->offset(),_list.length()+1,map->offset());
 }
 }
#endif// ASSERT

intindex = add(map);
 map->_index = index;
returnindex;
}

classAddDerivedOop : publicDerivedOopClosure {
public:
enum {
 SkipNull = true, NeedsLock = true
 };

virtualvoiddo_derived_oop(derived_base* base, derived_pointer* derived) {
#if COMPILER2_OR_JVMCI
DerivedPointerTable::add(derived, base);
#endif// COMPILER2_OR_JVMCI
 }
};

classProcessDerivedOop : publicDerivedOopClosure {
 OopClosure* _oop_cl;

public:
ProcessDerivedOop(OopClosure* oop_cl) :
_oop_cl(oop_cl) {}

enum {
 SkipNull = true, NeedsLock = true
 };

virtualvoiddo_derived_oop(derived_base* base, derived_pointer* derived) {
// All derived pointers must be processed before the base pointer of any derived pointer is processed.
// Otherwise, if two derived pointers use the same base, the second derived pointer will get an obscured
// offset, if the base pointer is processed in the first derived pointer.
 derived_pointer derived_base = to_derived_pointer(*reinterpret_cast<intptr_t*>(base));
intptr_t offset = *derived - derived_base;
 *derived = derived_base;
 _oop_cl->do_oop((oop*)derived);
 *derived = *derived + offset;
 }
};

classIgnoreDerivedOop : publicDerivedOopClosure {
 OopClosure* _oop_cl;

public:
enum {
 SkipNull = true, NeedsLock = true
 };

virtualvoiddo_derived_oop(derived_base* base, derived_pointer* derived) {}
};

voidOopMapSet::oops_do(const frame* fr, const RegisterMap* reg_map, OopClosure* f, DerivedPointerIterationMode mode) {
find_map(fr)->oops_do(fr, reg_map, f, mode);
}

voidOopMapSet::oops_do(const frame *fr, const RegisterMap* reg_map, OopClosure* f, DerivedOopClosure* df) {
find_map(fr)->oops_do(fr, reg_map, f, df);
}

voidImmutableOopMap::oops_do(const frame *fr, const RegisterMap *reg_map,
 OopClosure* oop_fn, DerivedOopClosure* derived_oop_fn) const {
assert(derived_oop_fn != nullptr, "sanity");
 OopMapDo<OopClosure, DerivedOopClosure, SkipNullValue> visitor(oop_fn, derived_oop_fn);
 visitor.oops_do(fr, reg_map, this);
}

voidImmutableOopMap::oops_do(const frame *fr, const RegisterMap *reg_map,
 OopClosure* oop_fn, DerivedPointerIterationMode derived_mode) const {
 ProcessDerivedOop process_cl(oop_fn);
 AddDerivedOop add_cl;
 IgnoreDerivedOop ignore_cl;
 DerivedOopClosure* derived_cl;
switch (derived_mode) {
case DerivedPointerIterationMode::_directly:
 derived_cl = &process_cl;
break;
case DerivedPointerIterationMode::_with_table:
 derived_cl = &add_cl;
break;
case DerivedPointerIterationMode::_ignore:
 derived_cl = &ignore_cl;
break;
default:
guarantee (false, "unreachable");
 }
 OopMapDo<OopClosure, DerivedOopClosure, SkipNullValue> visitor(oop_fn, derived_cl);
 visitor.oops_do(fr, reg_map, this);
}

voidImmutableOopMap::all_type_do(const frame *fr, OopMapClosure* fn) const {
 OopMapValue omv;
for (OopMapStream oms(this); !oms.is_done(); oms.next()) {
 omv = oms.current();
if (fn->handle_type(omv.type())) {
 fn->do_value(omv.reg(), omv.type());
 }
 }
}

voidImmutableOopMap::all_type_do(const frame *fr, OopMapValue::oop_types type, OopMapClosure* fn) const {
 OopMapValue omv;
for (OopMapStream oms(this); !oms.is_done(); oms.next()) {
 omv = oms.current();
if (omv.type() == type) {
 fn->do_value(omv.reg(), omv.type());
 }
 }
}

staticvoidupdate_register_map1(const ImmutableOopMap* oopmap, const frame* fr, RegisterMap* reg_map) {
for (OopMapStream oms(oopmap); !oms.is_done(); oms.next()) {
 OopMapValue omv = oms.current();
if (omv.type() == OopMapValue::callee_saved_value) {
 VMReg reg = omv.content_reg();
 address loc = fr->oopmapreg_to_location(omv.reg(), reg_map);
 reg_map->set_location(reg, loc);
 }
 }
}

// Update callee-saved register info for the following frame
voidImmutableOopMap::update_register_map(const frame *fr, RegisterMap *reg_map) const {
 CodeBlob* cb = fr->cb();
assert(cb != nullptr, "no codeblob");
// Any reg might be saved by a safepoint handler (see generate_handler_blob).
assert( reg_map->_update_for_id == nullptr || fr->is_older(reg_map->_update_for_id),
"already updated this map; do not 'update' it twice!" );
DEBUG_ONLY(reg_map->_update_for_id = fr->id());

// Check if caller must update oop argument
assert((reg_map->include_argument_oops() ||
 !cb->caller_must_gc_arguments(reg_map->thread())),
"include_argument_oops should already be set");

// Scan through oopmap and find location of all callee-saved registers
// (we do not do update in place, since info could be overwritten)

update_register_map1(this, fr, reg_map);
}

const ImmutableOopMap* OopMapSet::find_map(const frame *fr) {
returnfind_map(fr->cb(), fr->pc());
}

const ImmutableOopMap* OopMapSet::find_map(const CodeBlob* cb, address pc) {
assert(cb != nullptr, "no codeblob");
const ImmutableOopMap* map = cb->oop_map_for_return_address(pc);
assert(map != nullptr, "no ptr map found");
return map;
}

// Update callee-saved register info for the following frame
voidOopMapSet::update_register_map(const frame *fr, RegisterMap *reg_map) {
find_map(fr)->update_register_map(fr, reg_map);
}

//=============================================================================
// Non-Product code

#ifndef PRODUCT
voidOopMapSet::trace_codeblob_maps(const frame *fr, const RegisterMap *reg_map) {
// Print oopmap and regmap
 tty->print_cr("------ ");
 CodeBlob* cb = fr->cb();
const ImmutableOopMapSet* maps = cb->oop_maps();
const ImmutableOopMap* map = cb->oop_map_for_return_address(fr->pc());
 map->print();
if( cb->is_nmethod() ) {
 nmethod* nm = (nmethod*)cb;
// native wrappers have no scope data, it is implied
if (nm->is_native_method()) {
 tty->print("bci: 0 (native)");
 } else {
 ScopeDesc* scope = nm->scope_desc_at(fr->pc());
 tty->print("bci: %d ",scope->bci());
 }
 }
 tty->cr();
 fr->print_on(tty);
 tty->print("");
 cb->print_value_on(tty); tty->cr();
if (reg_map != nullptr) {
 reg_map->print();
 }
 tty->print_cr("------ ");

}
#endif// PRODUCT

// Printing code is present in product build for -XX:+PrintAssembly.

static
voidprint_register_type(OopMapValue::oop_types x, VMReg optional,
 outputStream* st) {
switch( x ) {
case OopMapValue::oop_value:
 st->print("Oop");
break;
case OopMapValue::narrowoop_value:
 st->print("NarrowOop");
break;
case OopMapValue::callee_saved_value:
 st->print("Callers_");
 optional->print_on(st);
break;
case OopMapValue::derived_oop_value:
 st->print("Derived_oop_");
 optional->print_on(st);
break;
default:
ShouldNotReachHere();
 }
}

voidOopMapValue::print_on(outputStream* st) const {
reg()->print_on(st);
 st->print("=");
print_register_type(type(),content_reg(),st);
 st->print("");
}

voidOopMapValue::print() const { print_on(tty); }

voidImmutableOopMap::print_on(outputStream* st) const {
 OopMapValue omv;
 st->print("ImmutableOopMap {");
for(OopMapStream oms(this); !oms.is_done(); oms.next()) {
 omv = oms.current();
 omv.print_on(st);
 }
 st->print("}");
}

voidImmutableOopMap::print() const { print_on(tty); }

voidOopMap::print_on(outputStream* st) const {
 OopMapValue omv;
 st->print("OopMap {");
for(OopMapStream oms((OopMap*)this); !oms.is_done(); oms.next()) {
 omv = oms.current();
 omv.print_on(st);
 }
// Print hex offset in addition.
 st->print("off=%d/0x%x}", (int) offset(), (int) offset());
}

voidOopMap::print() const { print_on(tty); }

voidImmutableOopMapSet::print_on(outputStream* st) const {
const ImmutableOopMap* last = nullptr;
constint len = count();

 st->print_cr("ImmutableOopMapSet contains %d OopMaps", len);

for (int i = 0; i < len; i++) {
const ImmutableOopMapPair* pair = pair_at(i);
const ImmutableOopMap* map = pair->get_from(this);
if (map != last) {
 st->cr();
 map->print_on(st);
 st->print(" pc offsets: ");
 }
 last = map;
 st->print("%d ", pair->pc_offset());
 }
 st->cr();
}

voidImmutableOopMapSet::print() const { print_on(tty); }

voidOopMapSet::print_on(outputStream* st) const {
constint len = _list.length();

 st->print_cr("OopMapSet contains %d OopMaps", len);

for( int i = 0; i < len; i++) {
 OopMap* m = at(i);
 st->print_cr("#%d ",i);
 m->print_on(st);
 st->cr();
 }
 st->cr();
}

voidOopMapSet::print() const { print_on(tty); }

boolOopMap::equals(const OopMap* other) const {
if (other->_omv_count != _omv_count) {
returnfalse;
 }
if (other->write_stream()->position() != write_stream()->position()) {
returnfalse;
 }
if (memcmp(other->write_stream()->buffer(), write_stream()->buffer(), write_stream()->position()) != 0) {
returnfalse;
 }
returntrue;
}

intImmutableOopMapSet::find_slot_for_offset(int pc_offset) const {
// we might not have an oopmap at asynchronous (non-safepoint) stackwalks
 ImmutableOopMapPair* pairs = get_pairs();
for (int i = 0; i < _count; ++i) {
if (pairs[i].pc_offset() >= pc_offset) {
 ImmutableOopMapPair* last = &pairs[i];
return last->pc_offset() == pc_offset ? i : -1;
 }
 }
return -1;
}

const ImmutableOopMap* ImmutableOopMapSet::find_map_at_offset(int pc_offset) const {
 ImmutableOopMapPair* pairs = get_pairs();
 ImmutableOopMapPair* last = nullptr;

for (int i = 0; i < _count; ++i) {
if (pairs[i].pc_offset() >= pc_offset) {
 last = &pairs[i];
break;
 }
 }

// Heal Coverity issue: potential index out of bounds access.
guarantee(last != nullptr, "last may not be null");
assert(last->pc_offset() == pc_offset, "oopmap not found");
return last->get_from(this);
}

ImmutableOopMap::ImmutableOopMap(const OopMap* oopmap)
 : _count(oopmap->count()), _num_oops(oopmap->num_oops()) {
 _num_oops = oopmap->num_oops();
 _has_derived_oops = oopmap->has_derived_oops();
 address addr = data_addr();
 oopmap->copy_and_sort_data_to(addr);
}

boolImmutableOopMap::has_any(OopMapValue::oop_types type) const {
for (OopMapStream oms(this); !oms.is_done(); oms.next()) {
if (oms.current().type() == type) {
returntrue;
 }
 }
returnfalse;
}

#ifdef ASSERT
intImmutableOopMap::nr_of_bytes() const {
 OopMapStream oms(this);

while (!oms.is_done()) {
 oms.next();
 }
returnsizeof(ImmutableOopMap) + oms.stream_position();
}
#endif

ImmutableOopMapBuilder::ImmutableOopMapBuilder(const OopMapSet* set) : _set(set), _empty(nullptr), _last(nullptr), _empty_offset(-1), _last_offset(-1), _offset(0), _required(-1), _new_set(nullptr) {
 _mapping = NEW_RESOURCE_ARRAY(Mapping, _set->size());
}

intImmutableOopMapBuilder::size_for(const OopMap* map) const {
returnalign_up((int)sizeof(ImmutableOopMap) + map->data_size(), 8);
}

intImmutableOopMapBuilder::heap_size() {
int base = sizeof(ImmutableOopMapSet);
 base = align_up(base, 8);

// all of ours pc / offset pairs
int pairs = _set->size() * sizeof(ImmutableOopMapPair);
 pairs = align_up(pairs, 8);

for (int i = 0; i < _set->size(); ++i) {
int size = 0;
 OopMap* map = _set->at(i);

if (is_empty(map)) {
/* only keep a single empty map in the set */
if (has_empty()) {
 _mapping[i].set(Mapping::OOPMAP_EMPTY, _empty_offset, 0, map, _empty);
 } else {
 _empty_offset = _offset;
 _empty = map;
 size = size_for(map);
 _mapping[i].set(Mapping::OOPMAP_NEW, _offset, size, map);
 }
 } elseif (is_last_duplicate(map)) {
/* if this entry is identical to the previous one, just point it there */
 _mapping[i].set(Mapping::OOPMAP_DUPLICATE, _last_offset, 0, map, _last);
 } else {
/* not empty, not an identical copy of the previous entry */
 size = size_for(map);
 _mapping[i].set(Mapping::OOPMAP_NEW, _offset, size, map);
 _last_offset = _offset;
 _last = map;
 }

assert(_mapping[i]._map == map, "check");
 _offset += size;
 }

int total = base + pairs + _offset;
DEBUG_ONLY(total += 8);
 _required = total;
return total;
}

voidImmutableOopMapBuilder::fill_pair(ImmutableOopMapPair* pair, const OopMap* map, int offset, const ImmutableOopMapSet* set) {
assert(offset < set->nr_of_bytes(), "check");
new ((address) pair) ImmutableOopMapPair(map->offset(), offset);
}

intImmutableOopMapBuilder::fill_map(ImmutableOopMapPair* pair, const OopMap* map, int offset, const ImmutableOopMapSet* set) {
fill_pair(pair, map, offset, set);
 address addr = (address) pair->get_from(_new_set); // location of the ImmutableOopMap

new (addr) ImmutableOopMap(map);
returnsize_for(map);
}

voidImmutableOopMapBuilder::fill(ImmutableOopMapSet* set, int sz) {
 ImmutableOopMapPair* pairs = set->get_pairs();

for (int i = 0; i < set->count(); ++i) {
const OopMap* map = _mapping[i]._map;
 ImmutableOopMapPair* pair = nullptr;
int size = 0;

if (_mapping[i]._kind == Mapping::OOPMAP_NEW) {
 size = fill_map(&pairs[i], map, _mapping[i]._offset, set);
 } elseif (_mapping[i]._kind == Mapping::OOPMAP_DUPLICATE || _mapping[i]._kind == Mapping::OOPMAP_EMPTY) {
fill_pair(&pairs[i], map, _mapping[i]._offset, set);
 }

//const ImmutableOopMap* nv = set->find_map_at_offset(map->offset());
//assert(memcmp(map->data(), nv->data_addr(), map->data_size()) == 0, "check identity");
 }
}

#ifdef ASSERT
voidImmutableOopMapBuilder::verify(address buffer, int size, const ImmutableOopMapSet* set) {
for (int i = 0; i < 8; ++i) {
assert(buffer[size - 8 + i] == (unsignedchar) 0xff, "overwritten memory check");
 }

for (int i = 0; i < set->count(); ++i) {
const ImmutableOopMapPair* pair = set->pair_at(i);
assert(pair->oopmap_offset() < set->nr_of_bytes(), "check size");
const ImmutableOopMap* map = pair->get_from(set);
int nr_of_bytes = map->nr_of_bytes();
assert(pair->oopmap_offset() + nr_of_bytes <= set->nr_of_bytes(), "check size + size");
 }
}
#endif

ImmutableOopMapSet* ImmutableOopMapBuilder::generate_into(address buffer) {
DEBUG_ONLY(memset(&buffer[_required-8], 0xff, 8));

 _new_set = new (buffer) ImmutableOopMapSet(_set, _required);
fill(_new_set, _required);

DEBUG_ONLY(verify(buffer, _required, _new_set));

return _new_set;
}

ImmutableOopMapSet* ImmutableOopMapBuilder::build() {
 _required = heap_size();

// We need to allocate a chunk big enough to hold the ImmutableOopMapSet and all of its ImmutableOopMaps
 address buffer = NEW_C_HEAP_ARRAY(unsignedchar, _required, mtCode);
returngenerate_into(buffer);
}

ImmutableOopMapSet* ImmutableOopMapSet::build_from(const OopMapSet* oopmap_set) {
 ResourceMark mark;
 ImmutableOopMapBuilder builder(oopmap_set);
return builder.build();
}

void ImmutableOopMapSet::operatordelete(void* p) {
FREE_C_HEAP_ARRAY(unsignedchar, p);
}

//------------------------------DerivedPointerTable---------------------------

#if COMPILER2_OR_JVMCI

classDerivedPointerTable::Entry : public CHeapObj<mtCompiler> {
 derived_pointer* _location; // Location of derived pointer, also pointing to base
intptr_t _offset; // Offset from base pointer
 Entry* volatile _next;

static Entry* volatile* next_ptr(Entry& entry) { return &entry._next; }

public:
Entry(derived_pointer* location, intptr_t offset) :
_location(location), _offset(offset), _next(nullptr) {}

 derived_pointer* location() const { return _location; }
intptr_toffset() const { return _offset; }
 Entry* next() const { return _next; }

typedef LockFreeStack<Entry, &next_ptr> List;
static List* _list;
};

DerivedPointerTable::Entry::List* DerivedPointerTable::Entry::_list = nullptr;
bool DerivedPointerTable::_active = false;

boolDerivedPointerTable::is_empty() {
return Entry::_list == nullptr || Entry::_list->empty();
}

voidDerivedPointerTable::clear() {
// The first time, we create the list. Otherwise it should be
// empty. If not, then we have probably forgotton to call
// update_pointers after last GC/Scavenge.
assert (!_active, "should not be active");
assert(is_empty(), "table not empty");
if (Entry::_list == nullptr) {
void* mem = NEW_C_HEAP_OBJ(Entry::List, mtCompiler);
 Entry::_list = ::new (mem) Entry::List();
 }
 _active = true;
}

voidDerivedPointerTable::add(derived_pointer* derived_loc, derived_base* base_loc) {
assert(Universe::heap()->is_in_or_null((void*)*base_loc), "not an oop");
assert(derived_loc != (void*)base_loc, "Base and derived in same location");
 derived_pointer base_loc_as_derived_pointer =
static_cast<derived_pointer>(reinterpret_cast<intptr_t>(base_loc));
assert(*derived_loc != base_loc_as_derived_pointer, "location already added");
assert(Entry::_list != nullptr, "list must exist");
assert(is_active(), "table must be active here");
intptr_t offset = *derived_loc - to_derived_pointer(*reinterpret_cast<intptr_t*>(base_loc));
// This assert is invalid because derived pointers can be
// arbitrarily far away from their base.
// assert(offset >= -1000000, "wrong derived pointer info");

if (TraceDerivedPointers) {
 tty->print_cr(
"Add derived pointer@" INTPTR_FORMAT
" - Derived: " INTPTR_FORMAT
" Base: " INTPTR_FORMAT " (@" INTPTR_FORMAT ") (Offset: %zd)",
p2i(derived_loc), derived_pointer_value(*derived_loc), intptr_t(*base_loc), p2i(base_loc), offset
 );
 }
// Set derived oop location to point to base.
 *derived_loc = base_loc_as_derived_pointer;
 Entry* entry = newEntry(derived_loc, offset);
 Entry::_list->push(*entry);
}

voidDerivedPointerTable::update_pointers() {
assert(Entry::_list != nullptr, "list must exist");
 Entry* entries = Entry::_list->pop_all();
while (entries != nullptr) {
 Entry* entry = entries;
 entries = entry->next();
 derived_pointer* derived_loc = entry->location();
intptr_t offset = entry->offset();
// The derived oop was setup to point to location of base
 oop base = **reinterpret_cast<oop**>(derived_loc);
assert(Universe::heap()->is_in_or_null(base), "must be an oop");

 derived_pointer derived_base = to_derived_pointer(cast_from_oop<intptr_t>(base));
 *derived_loc = derived_base + offset;
assert(*derived_loc - derived_base == offset, "sanity check");

// assert(offset >= 0 && offset <= (intptr_t)(base->size() << LogHeapWordSize), "offset: %ld base->size: %zu relative: %d", offset, base->size() << LogHeapWordSize, *(intptr_t*)derived_loc <= 0);

if (TraceDerivedPointers) {
 tty->print_cr("Updating derived pointer@" INTPTR_FORMAT
" - Derived: " INTPTR_FORMAT " Base: " INTPTR_FORMAT " (Offset: %zd)",
p2i(derived_loc), derived_pointer_value(*derived_loc), p2i(base), offset);
 }

// Delete entry
delete entry;
 }
assert(Entry::_list->empty(), "invariant");
 _active = false;
}

#endif// COMPILER2_OR_JVMCI