| /* |
| * Copyright (c) 1999, 2013, 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 |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #ifndef SHARE_VM_CI_CIFIELD_HPP |
| #define SHARE_VM_CI_CIFIELD_HPP |
| |
| #include "ci/ciClassList.hpp" |
| #include "ci/ciConstant.hpp" |
| #include "ci/ciFlags.hpp" |
| #include "ci/ciInstance.hpp" |
| |
| // ciField |
| // |
| // This class represents the result of a field lookup in the VM. |
| // The lookup may not succeed, in which case the information in |
| // the ciField will be incomplete. |
| class ciField : public ResourceObj { |
| CI_PACKAGE_ACCESS |
| friend class ciEnv; |
| friend class ciInstanceKlass; |
| friend class NonStaticFieldFiller; |
| |
| private: |
| ciFlags _flags; |
| ciInstanceKlass* _holder; |
| ciSymbol* _name; |
| ciSymbol* _signature; |
| ciType* _type; |
| int _offset; |
| bool _is_constant; |
| ciInstanceKlass* _known_to_link_with_put; |
| ciInstanceKlass* _known_to_link_with_get; |
| ciConstant _constant_value; |
| |
| ciType* compute_type(); |
| ciType* compute_type_impl(); |
| |
| ciField(ciInstanceKlass* klass, int index); |
| ciField(fieldDescriptor* fd); |
| |
| // shared constructor code |
| void initialize_from(fieldDescriptor* fd); |
| |
| public: |
| ciFlags flags() { return _flags; } |
| |
| // Of which klass is this field a member? |
| // |
| // Usage note: the declared holder of a field is the class |
| // referenced by name in the bytecodes. The canonical holder |
| // is the most general class which holds the field. This |
| // method returns the canonical holder. The declared holder |
| // can be accessed via a method in ciBytecodeStream. |
| // |
| // Ex. |
| // class A { |
| // public int f = 7; |
| // } |
| // class B extends A { |
| // public void test() { |
| // System.out.println(f); |
| // } |
| // } |
| // |
| // A java compiler is permitted to compile the access to |
| // field f as: |
| // |
| // getfield B.f |
| // |
| // In that case the declared holder of f would be B and |
| // the canonical holder of f would be A. |
| ciInstanceKlass* holder() { return _holder; } |
| |
| // Name of this field? |
| ciSymbol* name() { return _name; } |
| |
| // Signature of this field? |
| ciSymbol* signature() { return _signature; } |
| |
| // Of what type is this field? |
| ciType* type() { return (_type == NULL) ? compute_type() : _type; } |
| |
| // How is this field actually stored in memory? |
| BasicType layout_type() { return type2field[(_type == NULL) ? T_OBJECT : _type->basic_type()]; } |
| |
| // How big is this field in memory? |
| int size_in_bytes() { return type2aelembytes(layout_type()); } |
| |
| // What is the offset of this field? |
| int offset() { |
| assert(_offset >= 1, "illegal call to offset()"); |
| return _offset; |
| } |
| |
| // Same question, explicit units. (Fields are aligned to the byte level.) |
| int offset_in_bytes() { |
| return offset(); |
| } |
| |
| // Is this field shared? |
| bool is_shared() { |
| // non-static fields of shared holders are cached |
| return _holder->is_shared() && !is_static(); |
| } |
| |
| // Is this field a constant? |
| // |
| // Clarification: A field is considered constant if: |
| // 1. The field is both static and final |
| // 2. The canonical holder of the field has undergone |
| // static initialization. |
| // 3. The field is not one of the special static/final |
| // non-constant fields. These are java.lang.System.in |
| // and java.lang.System.out. Abomination. |
| // |
| // A field is also considered constant if it is marked @Stable |
| // and is non-null (or non-zero, if a primitive). |
| // For non-static fields, the null/zero check must be |
| // arranged by the user, as constant_value().is_null_or_zero(). |
| bool is_constant() { return _is_constant; } |
| |
| // Get the constant value of this field. |
| ciConstant constant_value() { |
| assert(is_static() && is_constant(), "illegal call to constant_value()"); |
| return _constant_value; |
| } |
| |
| // Get the constant value of non-static final field in the given |
| // object. |
| ciConstant constant_value_of(ciObject* object) { |
| assert(!is_static() && is_constant(), "only if field is non-static constant"); |
| assert(object->is_instance(), "must be instance"); |
| return object->as_instance()->field_value(this); |
| } |
| |
| // Check for link time errors. Accessing a field from a |
| // certain class via a certain bytecode may or may not be legal. |
| // This call checks to see if an exception may be raised by |
| // an access of this field. |
| // |
| // Usage note: if the same field is accessed multiple times |
| // in the same compilation, will_link will need to be checked |
| // at each point of access. |
| bool will_link(ciInstanceKlass* accessing_klass, |
| Bytecodes::Code bc); |
| |
| // Java access flags |
| bool is_public () { return flags().is_public(); } |
| bool is_private () { return flags().is_private(); } |
| bool is_protected () { return flags().is_protected(); } |
| bool is_static () { return flags().is_static(); } |
| bool is_final () { return flags().is_final(); } |
| bool is_stable () { return flags().is_stable(); } |
| bool is_volatile () { return flags().is_volatile(); } |
| bool is_transient () { return flags().is_transient(); } |
| |
| bool is_call_site_target() { |
| ciInstanceKlass* callsite_klass = CURRENT_ENV->CallSite_klass(); |
| if (callsite_klass == NULL) |
| return false; |
| return (holder()->is_subclass_of(callsite_klass) && (name() == ciSymbol::target_name())); |
| } |
| |
| // Debugging output |
| void print(); |
| void print_name_on(outputStream* st); |
| }; |
| |
| #endif // SHARE_VM_CI_CIFIELD_HPP |