< prev index next > src/hotspot/share/ci/ciInstance.cpp
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/*
! * Copyright (c) 1999, 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.
/*
! * Copyright (c) 1999, 2026, 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.
*
*/
#include "ci/ciConstant.hpp"
#include "ci/ciField.hpp"
+ #include "ci/ciInlineKlass.hpp"
#include "ci/ciInstance.hpp"
#include "ci/ciInstanceKlass.hpp"
#include "ci/ciNullObject.hpp"
#include "ci/ciUtilities.inline.hpp"
#include "classfile/javaClasses.inline.hpp"
#include "classfile/vmClasses.hpp"
+ #include "oops/fieldStreams.hpp"
+ #include "oops/fieldStreams.inline.hpp"
#include "oops/oop.inline.hpp"
+ #include "oops/valuePayload.inline.hpp"
// ciInstance
//
// This class represents an instanceOop in the HotSpot virtual
// machine.
}
}
// ------------------------------------------------------------------
// ciInstance::field_value_impl
! ciConstant ciInstance::field_value_impl(BasicType field_btype, int offset) {
! ciConstant value = check_constant_value_cache(offset, field_btype);
if (value.is_valid()) {
return value;
}
VM_ENTRY_MARK;
oop obj = get_oop();
assert(obj != nullptr, "bad oop");
! switch(field_btype) {
! case T_BYTE: value = ciConstant(field_btype, obj->byte_field(offset)); break;
! case T_CHAR: value = ciConstant(field_btype, obj->char_field(offset)); break;
! case T_SHORT: value = ciConstant(field_btype, obj->short_field(offset)); break;
! case T_BOOLEAN: value = ciConstant(field_btype, obj->bool_field(offset)); break;
! case T_INT: value = ciConstant(field_btype, obj->int_field(offset)); break;
case T_FLOAT: value = ciConstant(obj->float_field(offset)); break;
case T_DOUBLE: value = ciConstant(obj->double_field(offset)); break;
case T_LONG: value = ciConstant(obj->long_field(offset)); break;
case T_OBJECT: // fall through
case T_ARRAY: {
! oop o = obj->obj_field(offset);
! // A field will be "constant" if it is known always to be
! // a non-null reference to an instance of a particular class,
! // or to a particular array. This can happen even if the instance
! // or array is not perm. In such a case, an "unloaded" ciArray
! // or ciInstance is created. The compiler may be able to use
! // information about the object's class (which is exact) or length.
! if (o == nullptr) {
! value = ciConstant(field_btype, ciNullObject::make());
! } else {
! value = ciConstant(field_btype, CURRENT_ENV->get_object(o));
}
break;
}
default:
! fatal("no field value: %s", type2name(field_btype));
}
add_to_constant_value_cache(offset, value);
return value;
}
// ------------------------------------------------------------------
// ciInstance::field_value
//
! // Constant value of a field.
ciConstant ciInstance::field_value(ciField* field) {
assert(is_loaded(), "invalid access - must be loaded");
assert(field->holder()->is_loaded(), "invalid access - holder must be loaded");
! assert(field->is_static() || klass()->is_subclass_of(field->holder()), "invalid access - must be subclass");
! return field_value_impl(field->type()->basic_type(), field->offset_in_bytes());
}
// ------------------------------------------------------------------
// ciInstance::field_value_by_offset
//
}
}
// ------------------------------------------------------------------
// ciInstance::field_value_impl
! ciConstant ciInstance::field_value_impl(ciField* field) {
! BasicType field_bt = field->type()->basic_type();
+ int offset = field->offset_in_bytes();
+ ciConstant value = check_constant_value_cache(offset, field_bt);
if (value.is_valid()) {
return value;
}
VM_ENTRY_MARK;
oop obj = get_oop();
assert(obj != nullptr, "bad oop");
! switch(field_bt) {
! case T_BYTE: value = ciConstant(field_bt, obj->byte_field(offset)); break;
! case T_CHAR: value = ciConstant(field_bt, obj->char_field(offset)); break;
! case T_SHORT: value = ciConstant(field_bt, obj->short_field(offset)); break;
! case T_BOOLEAN: value = ciConstant(field_bt, obj->bool_field(offset)); break;
! case T_INT: value = ciConstant(field_bt, obj->int_field(offset)); break;
case T_FLOAT: value = ciConstant(obj->float_field(offset)); break;
case T_DOUBLE: value = ciConstant(obj->double_field(offset)); break;
case T_LONG: value = ciConstant(obj->long_field(offset)); break;
case T_OBJECT: // fall through
case T_ARRAY: {
! if (field->is_flat()) {
+ assert(field->is_atomic(), "do not query atomically a non-atomic flat field");
+ InlineKlass* vk = field->type()->as_inline_klass()->get_InlineKlass();
+ FlatValuePayload payload = FlatValuePayload::construct_from_parts(obj, offset, vk, field->layout_kind());
+ oop res = payload.read(THREAD);
+ if (HAS_PENDING_EXCEPTION) {
+ CLEAR_PENDING_EXCEPTION;
+ return ciConstant();
+ }
+ value = ciConstant(field_bt, CURRENT_ENV->get_object(res));
+ } else {
+ oop o = obj->obj_field(offset);
! // A field will be "constant" if it is known always to be
! // a non-null reference to an instance of a particular class,
! // or to a particular array. This can happen even if the instance
! // or array is not perm. In such a case, an "unloaded" ciArray
! // or ciInstance is created. The compiler may be able to use
! // information about the object's class (which is exact) or length.
! if (o == nullptr) {
! value = ciConstant(field_bt, ciNullObject::make());
! } else {
! value = ciConstant(field_bt, CURRENT_ENV->get_object(o));
+ }
}
break;
}
default:
! fatal("no field value: %s", type2name(field_bt));
}
add_to_constant_value_cache(offset, value);
return value;
}
// ------------------------------------------------------------------
// ciInstance::field_value
//
! // Constant value of a field of any kind: a declared field, or a leaf field.
+ // For a flat declared field, a cached copy of the value object is returned.
+ //
+ // Since stable fields can be treated as "constant" but are not really, we need
+ // to cache the value of fields so that the compiler will observe only one value
+ // per field. We also need to ensure that leaf fields from a single stable
+ // flat declared field will be observed to be consistent with each other.
+ //
+ // To do so, we need to always fetch the whole declared field containing the
+ // desired field. If we want a sub-field of a flat field, we then extract the field
+ // out of the cached copy, using sub_field_value.
+ //
+ // In the case we request a non-flat field, or a declared field (possibly flat), there
+ // is no sub-field to extract and sub_field_value will not be called.
ciConstant ciInstance::field_value(ciField* field) {
assert(is_loaded(), "invalid access - must be loaded");
assert(field->holder()->is_loaded(), "invalid access - holder must be loaded");
! assert(field->is_static() || field->holder()->is_inlinetype() || klass()->is_subclass_of(field->holder()),
! "invalid access - must be subclass");
+ ciInstanceKlass* klass = this->klass()->as_instance_klass();
+ int containing_field_idx = klass->field_index_by_offset(field->offset_in_bytes());
+ ciField* containing_field = klass->declared_nonstatic_field_at(containing_field_idx);
+ if (containing_field->is_flat() && !containing_field->is_atomic()) {
+ assert(field != containing_field, "do not ask for a non atomic declared field");
+ return field_value_impl(field);
+ }
+ ciConstant containing_field_value = field_value_impl(containing_field);
+ if (!containing_field_value.is_valid()) {
+ return ciConstant();
+ }
+ if (field->original_holder() == nullptr) {
+ return containing_field_value;
+ }
+ ciObject* obj = containing_field_value.as_object();
+ if (obj->is_instance()) {
+ ciInstance* inst = obj->as_instance();
+ // inst->klass() must be an inline klass since it is the value of a flat field.
+ ciInlineKlass* inst_klass = inst->klass()->as_inline_klass();
+ ciField* field_in_value_klass = inst_klass->get_field_by_offset(inst_klass->payload_offset() + field->offset_in_bytes() - containing_field->offset_in_bytes(), false);
+ return inst->sub_field_value(field_in_value_klass);
+ } else if (obj->is_null_object()) {
+ return ciConstant::make_zero_or_null(field->type()->basic_type());
+ }
+ // obj should not be an array since we are trying to get a field inside it
+ ShouldNotReachHere();
+ return ciConstant();
+ }
+
+ // Extract a leaf field from a value object.
+ //
+ // This is used by field_value when getting the value of a sub-field. field_value
+ // will take care of getting the value of the declared field containing the requested
+ // field, and of caching (see the comment on field_value for why). But if we want the
+ // value of a sub-field, we need to extract it from the value of the declared field
+ // containing the said sub-field. This is what this function does.
+ //
+ // This is meant for internal used only. In particular, this function does not cache
+ // the result and must be called only on already cached values (to ensure consistency).
+ // field_value takes care of that.
+ ciConstant ciInstance::sub_field_value(ciField* field) {
+ precond(klass()->is_inlinetype());
+ precond(!field->is_flat());
+ int offset = field->offset_in_bytes();
+ BasicType field_btype = field->type()->basic_type();
+
+ ciConstant value;
+ VM_ENTRY_MARK;
+ oop obj = get_oop();
+ assert(obj != nullptr, "bad oop");
+ switch(field_btype) {
+ case T_BYTE: value = ciConstant(field_btype, obj->byte_field(offset)); break;
+ case T_CHAR: value = ciConstant(field_btype, obj->char_field(offset)); break;
+ case T_SHORT: value = ciConstant(field_btype, obj->short_field(offset)); break;
+ case T_BOOLEAN: value = ciConstant(field_btype, obj->bool_field(offset)); break;
+ case T_INT: value = ciConstant(field_btype, obj->int_field(offset)); break;
+ case T_FLOAT: value = ciConstant(obj->float_field(offset)); break;
+ case T_DOUBLE: value = ciConstant(obj->double_field(offset)); break;
+ case T_LONG: value = ciConstant(obj->long_field(offset)); break;
+ case T_OBJECT: // fall through
+ case T_ARRAY: {
+ oop o = obj->obj_field(offset);
+
+ // A field will be "constant" if it is known always to be
+ // a non-null reference to an instance of a particular class,
+ // or to a particular array. This can happen even if the instance
+ // or array is not perm. In such a case, an "unloaded" ciArray
+ // or ciInstance is created. The compiler may be able to use
+ // information about the object's class (which is exact) or length.
+
+ if (o == nullptr) {
+ value = ciConstant(field_btype, ciNullObject::make());
+ } else {
+ value = ciConstant(field_btype, CURRENT_ENV->get_object(o));
+ }
+ break;
+ }
+ default:
+ fatal("no field value: %s", type2name(field_btype));
+ }
+ return value;
}
// ------------------------------------------------------------------
// ciInstance::field_value_by_offset
//
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