src/hotspot/share/runtime/stackValue.hpp

/*
 * Copyright (c) 1997, 2024, 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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#ifndef SHARE_RUNTIME_STACKVALUE_HPP
#define SHARE_RUNTIME_STACKVALUE_HPP

#include "code/location.hpp"
#include "runtime/handles.hpp"

class BasicLock;
class frame;
class RegisterMap;
class ScopeValue;

class StackValue : public ResourceObj {
 private:
  BasicType _type;
  intptr_t  _integer_value; // Blank java stack slot value
  Handle    _handle_value;  // Java stack slot value interpreted as a Handle
 public:

  StackValue(intptr_t value) {
    _type              = T_INT;
    _integer_value     = value;
  }

  StackValue(Handle value, intptr_t scalar_replaced = 0) {
    _type                = T_OBJECT;
    _integer_value       = scalar_replaced;
    _handle_value        = value;
    assert(_integer_value == 0 ||  _handle_value.is_null(), "not null object should not be marked as scalar replaced");
  }

  StackValue() {
    _type           = T_CONFLICT;
    _integer_value  = 0;
  }

  // Only used during deopt- preserve object type.
  StackValue(intptr_t o, BasicType t) {
    assert(t == T_OBJECT, "should not be used");
    _type          = t;
    _integer_value = o;
  }

  Handle get_obj() const {
    assert(type() == T_OBJECT, "type check");
    return _handle_value;
  }

  bool obj_is_scalar_replaced() const {
    assert(type() == T_OBJECT, "type check");
    return _integer_value != 0;
  }

  void set_obj(Handle value) {
    assert(type() == T_OBJECT, "type check");
    _handle_value = value;
  }

  intptr_t get_intptr() const {
    assert(type() == T_INT, "type check");
    return _integer_value;
  }

  // For special case in deopt.
  intptr_t get_intptr(BasicType t) const {
    assert(t == T_OBJECT && type() == T_OBJECT, "type check");
    return _integer_value;
  }

  void set_intptr(intptr_t value) {
    assert(type() == T_INT, "type check");
    _integer_value = value;
  }

  // The jint value is always at offset 0 of the stack slot. On big endian platforms
  // this is the location of the high word therefore we cannot just cast to jint.
  jint get_jint() const {
    assert(type() == T_INT, "type check");
    return *(jint*)&_integer_value;
  }

  void set_jint(jint value) {
    assert(type() == T_INT, "type check");
    *(jint*)&_integer_value = value;
  }

  BasicType type() const { return  _type; }

  bool equal(StackValue *value) {
    if (_type != value->_type) return false;
    if (_type == T_OBJECT)
      return (_handle_value == value->_handle_value);
    else {
      assert(_type == T_INT, "sanity check");
      // [phh] compare only low addressed portions of intptr_t slots
      return (*(int *)&_integer_value == *(int *)&value->_integer_value);
    }
  }

  static StackValue* create_stack_value_from_oop_location(stackChunkOop chunk, void* addr);
  static StackValue* create_stack_value_from_narrowOop_location(stackChunkOop chunk, void* addr, bool is_register);

  static BasicLock*  resolve_monitor_lock(const frame& fr, Location location);

  template<typename RegisterMapT>
  static StackValue* create_stack_value(const frame* fr, const RegisterMapT* reg_map, ScopeValue* sv);

  template<typename RegisterMapT>
  static address stack_value_address(const frame* fr, const RegisterMapT* reg_map, ScopeValue* sv);

#ifndef PRODUCT
 public:
  // Printing
  void print_on(outputStream* st) const;
#endif

 private:
   template<typename RegisterMapT>
   static StackValue* create_stack_value(ScopeValue* sv, address value_addr, const RegisterMapT* reg_map);
};

#endif // SHARE_RUNTIME_STACKVALUE_HPP