/*
* Copyright (c) 2003, 2012, 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.
*
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#ifndef SHARE_VM_OOPS_CONSTMETHODOOP_HPP
#define SHARE_VM_OOPS_CONSTMETHODOOP_HPP
#include "oops/oop.hpp"
// An ConstMethod* represents portions of a Java method which
// do not vary.
//
// Memory layout (each line represents a word). Note that most
// applications load thousands of methods, so keeping the size of this
// structure small has a big impact on footprint.
//
// |------------------------------------------------------|
// | header |
// | klass |
// |------------------------------------------------------|
// | fingerprint 1 |
// | fingerprint 2 |
// | constants (oop) |
// | stackmap_data (oop) |
// | constMethod_size |
// | interp_kind | flags | code_size |
// | name index | signature index |
// | method_idnum | generic_signature_index |
// |------------------------------------------------------|
// | |
// | byte codes |
// | |
// |------------------------------------------------------|
// | compressed linenumber table |
// | (see class CompressedLineNumberReadStream) |
// | (note that length is unknown until decompressed) |
// | (access flags bit tells whether table is present) |
// | (indexed from start of ConstMethod*) |
// | (elements not necessarily sorted!) |
// |------------------------------------------------------|
// | localvariable table elements + length (length last) |
// | (length is u2, elements are 6-tuples of u2) |
// | (see class LocalVariableTableElement) |
// | (access flags bit tells whether table is present) |
// | (indexed from end of ConstMethod*) |
// |------------------------------------------------------|
// | exception table + length (length last) |
// | (length is u2, elements are 4-tuples of u2) |
// | (see class ExceptionTableElement) |
// | (access flags bit tells whether table is present) |
// | (indexed from end of ConstMethod*) |
// |------------------------------------------------------|
// | checked exceptions elements + length (length last) |
// | (length is u2, elements are u2) |
// | (see class CheckedExceptionElement) |
// | (access flags bit tells whether table is present) |
// | (indexed from end of ConstMethod*) |
// |------------------------------------------------------|
// Utitily class decribing elements in checked exceptions table inlined in Method*.
class CheckedExceptionElement VALUE_OBJ_CLASS_SPEC {
public:
u2 class_cp_index;
};
// Utitily class decribing elements in local variable table inlined in Method*.
class LocalVariableTableElement VALUE_OBJ_CLASS_SPEC {
public:
u2 start_bci;
u2 length;
u2 name_cp_index;
u2 descriptor_cp_index;
u2 signature_cp_index;
u2 slot;
};
// Utitily class describing elements in exception table
class ExceptionTableElement VALUE_OBJ_CLASS_SPEC {
public:
u2 start_pc;
u2 end_pc;
u2 handler_pc;
u2 catch_type_index;
};
class ConstMethod : public MetaspaceObj {
friend class VMStructs;
private:
enum {
_has_linenumber_table = 1,
_has_checked_exceptions = 2,
_has_localvariable_table = 4,
_has_exception_table = 8
};
// Bit vector of signature
// Callers interpret 0=not initialized yet and
// -1=too many args to fix, must parse the slow way.
// The real initial value is special to account for nonatomicity of 64 bit
// loads and stores. This value may updated and read without a lock by
// multiple threads, so is volatile.
volatile uint64_t _fingerprint;
ConstantPool* _constants; // Constant pool
// Raw stackmap data for the method
Array<u1>* _stackmap_data;
int _constMethod_size;
jbyte _interpreter_kind;
jbyte _flags;
// Size of Java bytecodes allocated immediately after Method*.
u2 _code_size;
u2 _name_index; // Method name (index in constant pool)
u2 _signature_index; // Method signature (index in constant pool)
u2 _method_idnum; // unique identification number for the method within the class
// initially corresponds to the index into the methods array.
// but this may change with redefinition
u2 _generic_signature_index; // Generic signature (index in constant pool, 0 if absent)
// Constructor
ConstMethod(int byte_code_size,
int compressed_line_number_size,
int localvariable_table_length,
int exception_table_length,
int checked_exceptions_length,
int size);
public:
static ConstMethod* allocate(ClassLoaderData* loader_data,
int byte_code_size,
int compressed_line_number_size,
int localvariable_table_length,
int exception_table_length,
int checked_exceptions_length,
TRAPS);
bool is_constMethod() const { return true; }
// Inlined tables
void set_inlined_tables_length(int checked_exceptions_len,
int compressed_line_number_size,
int localvariable_table_len,
int exception_table_len);
bool has_linenumber_table() const
{ return (_flags & _has_linenumber_table) != 0; }
bool has_checked_exceptions() const
{ return (_flags & _has_checked_exceptions) != 0; }
bool has_localvariable_table() const
{ return (_flags & _has_localvariable_table) != 0; }
bool has_exception_handler() const
{ return (_flags & _has_exception_table) != 0; }
void set_interpreter_kind(int kind) { _interpreter_kind = kind; }
int interpreter_kind(void) const { return _interpreter_kind; }
// constant pool
ConstantPool* constants() const { return _constants; }
void set_constants(ConstantPool* c) { _constants = c; }
Method* method() const;
// stackmap table data
Array<u1>* stackmap_data() const { return _stackmap_data; }
void set_stackmap_data(Array<u1>* sd) { _stackmap_data = sd; }
bool has_stackmap_table() const { return _stackmap_data != NULL; }
void init_fingerprint() {
const uint64_t initval = CONST64(0x8000000000000000);
_fingerprint = initval;
}
uint64_t fingerprint() const {
// Since reads aren't atomic for 64 bits, if any of the high or low order
// word is the initial value, return 0. See init_fingerprint for initval.
uint high_fp = (uint)(_fingerprint >> 32);
if ((int) _fingerprint == 0 || high_fp == 0x80000000) {
return 0L;
} else {
return _fingerprint;
}
}
uint64_t set_fingerprint(uint64_t new_fingerprint) {
#ifdef ASSERT
// Assert only valid if complete/valid 64 bit _fingerprint value is read.
uint64_t oldfp = fingerprint();
#endif // ASSERT
_fingerprint = new_fingerprint;
assert(oldfp == 0L || new_fingerprint == oldfp,
"fingerprint cannot change");
assert(((new_fingerprint >> 32) != 0x80000000) && (int)new_fingerprint !=0,
"fingerprint should call init to set initial value");
return new_fingerprint;
}
// name
int name_index() const { return _name_index; }
void set_name_index(int index) { _name_index = index; }
// signature
int signature_index() const { return _signature_index; }
void set_signature_index(int index) { _signature_index = index; }
// generics support
int generic_signature_index() const { return _generic_signature_index; }
void set_generic_signature_index(int index) { _generic_signature_index = index; }
// Sizing
static int header_size() {
return sizeof(ConstMethod)/HeapWordSize;
}
// Size needed
static int size(int code_size, int compressed_line_number_size,
int local_variable_table_length,
int exception_table_length,
int checked_exceptions_length);
int size() const { return _constMethod_size;}
void set_constMethod_size(int size) { _constMethod_size = size; }
// code size
int code_size() const { return _code_size; }
void set_code_size(int size) {
assert(max_method_code_size < (1 << 16),
"u2 is too small to hold method code size in general");
assert(0 <= size && size <= max_method_code_size, "invalid code size");
_code_size = size;
}
// linenumber table - note that length is unknown until decompression,
// see class CompressedLineNumberReadStream.
u_char* compressed_linenumber_table() const; // not preserved by gc
u2* checked_exceptions_length_addr() const;
u2* localvariable_table_length_addr() const;
u2* exception_table_length_addr() const;
// checked exceptions
int checked_exceptions_length() const;
CheckedExceptionElement* checked_exceptions_start() const;
// localvariable table
int localvariable_table_length() const;
LocalVariableTableElement* localvariable_table_start() const;
// exception table
int exception_table_length() const;
ExceptionTableElement* exception_table_start() const;
// byte codes
void set_code(address code) {
if (code_size() > 0) {
memcpy(code_base(), code, code_size());
}
}
address code_base() const { return (address) (this+1); }
address code_end() const { return code_base() + code_size(); }
bool contains(address bcp) const { return code_base() <= bcp
&& bcp < code_end(); }
// Offset to bytecodes
static ByteSize codes_offset()
{ return in_ByteSize(sizeof(ConstMethod)); }
static ByteSize constants_offset()
{ return byte_offset_of(ConstMethod, _constants); }
// Unique id for the method
static const u2 MAX_IDNUM;
static const u2 UNSET_IDNUM;
u2 method_idnum() const { return _method_idnum; }
void set_method_idnum(u2 idnum) { _method_idnum = idnum; }
// Deallocation for RedefineClasses
void deallocate_contents(ClassLoaderData* loader_data);
bool is_klass() const { return false; }
DEBUG_ONLY(bool on_stack() { return false; })
private:
// Since the size of the compressed line number table is unknown, the
// offsets of the other variable sized sections are computed backwards
// from the end of the ConstMethod*.
// First byte after ConstMethod*
address constMethod_end() const
{ return (address)((oop*)this + _constMethod_size); }
// Last short in ConstMethod*
u2* last_u2_element() const
{ return (u2*)constMethod_end() - 1; }
public:
// Printing
void print_on (outputStream* st) const;
void print_value_on(outputStream* st) const;
const char* internal_name() const { return "{constMethod}"; }
// Verify
void verify_on(outputStream* st);
};
#endif // SHARE_VM_OOPS_CONSTMETHODOOP_HPP