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/*
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* Copyright 1999-2006 Sun Microsystems, Inc. All Rights Reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*
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*/
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// ciField
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//
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// This class represents the result of a field lookup in the VM.
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// The lookup may not succeed, in which case the information in
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// the ciField will be incomplete.
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class ciField : public ResourceObj {
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CI_PACKAGE_ACCESS
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friend class ciEnv;
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friend class ciInstanceKlass;
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friend class NonStaticFieldFiller;
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private:
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ciFlags _flags;
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ciInstanceKlass* _holder;
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ciSymbol* _name;
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ciSymbol* _signature;
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ciType* _type;
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int _offset;
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bool _is_constant;
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ciInstanceKlass* _known_to_link_with;
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ciConstant _constant_value;
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// Used for will_link
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int _cp_index;
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ciType* compute_type();
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ciType* compute_type_impl();
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ciField(ciInstanceKlass* klass, int index);
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ciField(fieldDescriptor* fd);
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// shared constructor code
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void initialize_from(fieldDescriptor* fd);
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// The implementation of the print method.
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void print_impl(outputStream* st);
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public:
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ciFlags flags() { return _flags; }
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// Of which klass is this field a member?
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//
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// Usage note: the declared holder of a field is the class
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// referenced by name in the bytecodes. The canonical holder
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// is the most general class which holds the field. This
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// method returns the canonical holder. The declared holder
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// can be accessed via a method in ciBytecodeStream.
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//
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// Ex.
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// class A {
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// public int f = 7;
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// }
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// class B extends A {
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// public void test() {
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// System.out.println(f);
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// }
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// }
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//
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// A java compiler is permitted to compile the access to
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// field f as:
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//
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// getfield B.f
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//
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// In that case the declared holder of f would be B and
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// the canonical holder of f would be A.
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ciInstanceKlass* holder() { return _holder; }
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// Name of this field?
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ciSymbol* name() { return _name; }
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// Signature of this field?
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ciSymbol* signature() { return _signature; }
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// Of what type is this field?
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ciType* type() { return (_type == NULL) ? compute_type() : _type; }
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// How is this field actually stored in memory?
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BasicType layout_type() { return type2field[(_type == NULL) ? T_OBJECT : _type->basic_type()]; }
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// How big is this field in memory?
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int size_in_bytes() { return type2aelembytes[layout_type()]; }
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// What is the offset of this field?
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int offset() {
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assert(_offset >= 1, "illegal call to offset()");
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return _offset;
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}
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// Same question, explicit units. (Fields are aligned to the byte level.)
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int offset_in_bytes() {
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return offset();
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}
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// Is this field shared?
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bool is_shared() {
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// non-static fields of shared holders are cached
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return _holder->is_shared() && !is_static();
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}
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// Is this field a constant?
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//
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// Clarification: A field is considered constant if:
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// 1. The field is both static and final
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// 2. The canonical holder of the field has undergone
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// static initialization.
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// 3. If the field is an object or array, then the oop
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// in question is allocated in perm space.
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// 4. The field is not one of the special static/final
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// non-constant fields. These are java.lang.System.in
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// and java.lang.System.out. Abomination.
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//
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// Note: the check for case 4 is not yet implemented.
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bool is_constant() { return _is_constant; }
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// Get the constant value of this field.
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ciConstant constant_value() {
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assert(is_constant(), "illegal call to constant_value()");
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return _constant_value;
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}
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// Check for link time errors. Accessing a field from a
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// certain class via a certain bytecode may or may not be legal.
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// This call checks to see if an exception may be raised by
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// an access of this field.
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//
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// Usage note: if the same field is accessed multiple times
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// in the same compilation, will_link will need to be checked
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// at each point of access.
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bool will_link(ciInstanceKlass* accessing_klass,
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Bytecodes::Code bc);
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// Java access flags
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bool is_public () { return flags().is_public(); }
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bool is_private () { return flags().is_private(); }
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bool is_protected () { return flags().is_protected(); }
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bool is_static () { return flags().is_static(); }
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bool is_final () { return flags().is_final(); }
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bool is_volatile () { return flags().is_volatile(); }
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bool is_transient () { return flags().is_transient(); }
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// Debugging output
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void print();
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void print_name_on(outputStream* st);
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};
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