/* * Copyright 2003-2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.com if you need additional information or * have any questions. * */ // An constMethodOop 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 | // | method (oop) | // | stackmap_data (oop) | // | exception_table (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 constMethodOop) | // | (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 contMethodOop) | // |------------------------------------------------------| // | 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 constMethodOop) | // |------------------------------------------------------| // Utitily class decribing elements in checked exceptions table inlined in methodOop. class CheckedExceptionElement VALUE_OBJ_CLASS_SPEC { public: u2 class_cp_index; }; // Utitily class decribing elements in local variable table inlined in methodOop. 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; }; class constMethodOopDesc : public oopDesc { friend class constMethodKlass; friend class VMStructs; private: enum { _has_linenumber_table = 1, _has_checked_exceptions = 2, _has_localvariable_table = 4 }; // 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; volatile bool _is_conc_safe; // if true, safe for concurrent GC processing public: oop* oop_block_beg() const { return adr_method(); } oop* oop_block_end() const { return adr_exception_table() + 1; } private: // // The oop block. See comment in klass.hpp before making changes. // // Backpointer to non-const methodOop (needed for some JVMTI operations) methodOop _method; // Raw stackmap data for the method typeArrayOop _stackmap_data; // The exception handler table. 4-tuples of ints [start_pc, end_pc, // handler_pc, catch_type index] For methods with no exceptions the // table is pointing to Universe::the_empty_int_array typeArrayOop _exception_table; // // End of the oop block. // int _constMethod_size; jbyte _interpreter_kind; jbyte _flags; // Size of Java bytecodes allocated immediately after methodOop. 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) public: // Inlined tables void set_inlined_tables_length(int checked_exceptions_len, int compressed_line_number_size, int localvariable_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; } void set_interpreter_kind(int kind) { _interpreter_kind = kind; } int interpreter_kind(void) const { return _interpreter_kind; } // backpointer to non-const methodOop methodOop method() const { return _method; } void set_method(methodOop m) { oop_store_without_check((oop*)&_method, (oop) m); } // stackmap table data typeArrayOop stackmap_data() const { return _stackmap_data; } void set_stackmap_data(typeArrayOop sd) { oop_store_without_check((oop*)&_stackmap_data, (oop)sd); } bool has_stackmap_table() const { return _stackmap_data != NULL; } // exception handler table typeArrayOop exception_table() const { return _exception_table; } void set_exception_table(typeArrayOop e) { oop_store_without_check((oop*) &_exception_table, (oop) e); } bool has_exception_handler() const { return exception_table() != NULL && exception_table()->length() > 0; } 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(constMethodOopDesc)/HeapWordSize; } // Object size needed static int object_size(int code_size, int compressed_line_number_size, int local_variable_table_length, int checked_exceptions_length); int object_size() const { return _constMethod_size; } void set_constMethod_size(int size) { _constMethod_size = size; } // Is object parsable by gc bool object_is_parsable() { return object_size() > 0; } // 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; // checked exceptions int checked_exceptions_length() const; CheckedExceptionElement* checked_exceptions_start() const; // localvariable table int localvariable_table_length() const; LocalVariableTableElement* localvariable_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(constMethodOopDesc)); } // interpreter support static ByteSize exception_table_offset() { return byte_offset_of(constMethodOopDesc, _exception_table); } // Garbage collection support oop* adr_method() const { return (oop*)&_method; } oop* adr_stackmap_data() const { return (oop*)&_stackmap_data; } oop* adr_exception_table() const { return (oop*)&_exception_table; } bool is_conc_safe() { return _is_conc_safe; } void set_is_conc_safe(bool v) { _is_conc_safe = v; } // 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; } 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 constMethodOop. // First byte after constMethodOop address constMethod_end() const { return (address)((oop*)this + _constMethod_size); } // Last short in constMethodOop u2* last_u2_element() const { return (u2*)constMethod_end() - 1; } };