1 /* 2 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_OOPS_CONSTMETHODOOP_HPP 26 #define SHARE_VM_OOPS_CONSTMETHODOOP_HPP 27 28 #include "oops/oop.hpp" 29 #include "oops/typeArrayOop.hpp" 30 31 // An constMethodOop represents portions of a Java method which 32 // do not vary. 33 // 34 // Memory layout (each line represents a word). Note that most 35 // applications load thousands of methods, so keeping the size of this 36 // structure small has a big impact on footprint. 37 // 38 // |------------------------------------------------------| 39 // | header | 40 // | klass | 41 // |------------------------------------------------------| 42 // | fingerprint 1 | 43 // | fingerprint 2 | 44 // | method (oop) | 45 // | stackmap_data (oop) | 46 // | exception_table (oop) | 47 // | constMethod_size | 48 // | interp_kind | flags | code_size | 49 // | name index | signature index | 50 // | method_idnum | generic_signature_index | 51 // |------------------------------------------------------| 52 // | | 53 // | byte codes | 54 // | | 55 // |------------------------------------------------------| 56 // | compressed linenumber table | 57 // | (see class CompressedLineNumberReadStream) | 58 // | (note that length is unknown until decompressed) | 59 // | (access flags bit tells whether table is present) | 60 // | (indexed from start of constMethodOop) | 61 // | (elements not necessarily sorted!) | 62 // |------------------------------------------------------| 63 // | localvariable table elements + length (length last) | 64 // | (length is u2, elements are 6-tuples of u2) | 65 // | (see class LocalVariableTableElement) | 66 // | (access flags bit tells whether table is present) | 67 // | (indexed from end of contMethodOop) | 68 // |------------------------------------------------------| 69 // | checked exceptions elements + length (length last) | 70 // | (length is u2, elements are u2) | 71 // | (see class CheckedExceptionElement) | 72 // | (access flags bit tells whether table is present) | 73 // | (indexed from end of constMethodOop) | 74 // |------------------------------------------------------| 75 76 77 // Utitily class decribing elements in checked exceptions table inlined in methodOop. 78 class CheckedExceptionElement VALUE_OBJ_CLASS_SPEC { 79 public: 80 u2 class_cp_index; 81 }; 82 83 84 // Utitily class decribing elements in local variable table inlined in methodOop. 85 class LocalVariableTableElement VALUE_OBJ_CLASS_SPEC { 86 public: 87 u2 start_bci; 88 u2 length; 89 u2 name_cp_index; 90 u2 descriptor_cp_index; 91 u2 signature_cp_index; 92 u2 slot; 93 }; 94 95 96 class constMethodOopDesc : public oopDesc { 97 friend class constMethodKlass; 98 friend class VMStructs; 99 private: 100 enum { 101 _has_linenumber_table = 1, 102 _has_checked_exceptions = 2, 103 _has_localvariable_table = 4 104 }; 105 106 // Bit vector of signature 107 // Callers interpret 0=not initialized yet and 108 // -1=too many args to fix, must parse the slow way. 109 // The real initial value is special to account for nonatomicity of 64 bit 110 // loads and stores. This value may updated and read without a lock by 111 // multiple threads, so is volatile. 112 volatile uint64_t _fingerprint; 113 volatile bool _is_conc_safe; // if true, safe for concurrent GC processing 114 115 public: 116 oop* oop_block_beg() const { return adr_method(); } 117 oop* oop_block_end() const { return adr_exception_table() + 1; } 118 119 private: 120 // 121 // The oop block. See comment in klass.hpp before making changes. 122 // 123 124 // Backpointer to non-const methodOop (needed for some JVMTI operations) 125 methodOop _method; 126 127 // Raw stackmap data for the method 128 typeArrayOop _stackmap_data; 129 130 // The exception handler table. 4-tuples of ints [start_pc, end_pc, 131 // handler_pc, catch_type index] For methods with no exceptions the 132 // table is pointing to Universe::the_empty_int_array 133 typeArrayOop _exception_table; 134 135 // 136 // End of the oop block. 137 // 138 139 int _constMethod_size; 140 jbyte _interpreter_kind; 141 jbyte _flags; 142 143 // Size of Java bytecodes allocated immediately after methodOop. 144 u2 _code_size; 145 u2 _name_index; // Method name (index in constant pool) 146 u2 _signature_index; // Method signature (index in constant pool) 147 u2 _method_idnum; // unique identification number for the method within the class 148 // initially corresponds to the index into the methods array. 149 // but this may change with redefinition 150 u2 _generic_signature_index; // Generic signature (index in constant pool, 0 if absent) 151 152 public: 153 // Inlined tables 154 void set_inlined_tables_length(int checked_exceptions_len, 155 int compressed_line_number_size, 156 int localvariable_table_len); 157 158 bool has_linenumber_table() const 159 { return (_flags & _has_linenumber_table) != 0; } 160 161 bool has_checked_exceptions() const 162 { return (_flags & _has_checked_exceptions) != 0; } 163 164 bool has_localvariable_table() const 165 { return (_flags & _has_localvariable_table) != 0; } 166 167 void set_interpreter_kind(int kind) { _interpreter_kind = kind; } 168 int interpreter_kind(void) const { return _interpreter_kind; } 169 170 // backpointer to non-const methodOop 171 methodOop method() const { return _method; } 172 void set_method(methodOop m) { oop_store_without_check((oop*)&_method, (oop) m); } 173 174 175 // stackmap table data 176 typeArrayOop stackmap_data() const { return _stackmap_data; } 177 void set_stackmap_data(typeArrayOop sd) { 178 oop_store_without_check((oop*)&_stackmap_data, (oop)sd); 179 } 180 bool has_stackmap_table() const { return _stackmap_data != NULL; } 181 182 // exception handler table 183 typeArrayOop exception_table() const { return _exception_table; } 184 void set_exception_table(typeArrayOop e) { oop_store_without_check((oop*) &_exception_table, (oop) e); } 185 bool has_exception_handler() const { return exception_table() != NULL && exception_table()->length() > 0; } 186 187 void init_fingerprint() { 188 const uint64_t initval = CONST64(0x8000000000000000); 189 _fingerprint = initval; 190 } 191 192 uint64_t fingerprint() const { 193 // Since reads aren't atomic for 64 bits, if any of the high or low order 194 // word is the initial value, return 0. See init_fingerprint for initval. 195 uint high_fp = (uint)(_fingerprint >> 32); 196 if ((int) _fingerprint == 0 || high_fp == 0x80000000) { 197 return 0L; 198 } else { 199 return _fingerprint; 200 } 201 } 202 203 uint64_t set_fingerprint(uint64_t new_fingerprint) { 204 #ifdef ASSERT 205 // Assert only valid if complete/valid 64 bit _fingerprint value is read. 206 uint64_t oldfp = fingerprint(); 207 #endif // ASSERT 208 _fingerprint = new_fingerprint; 209 assert(oldfp == 0L || new_fingerprint == oldfp, 210 "fingerprint cannot change"); 211 assert(((new_fingerprint >> 32) != 0x80000000) && (int)new_fingerprint !=0, 212 "fingerprint should call init to set initial value"); 213 return new_fingerprint; 214 } 215 216 // name 217 int name_index() const { return _name_index; } 218 void set_name_index(int index) { _name_index = index; } 219 220 // signature 221 int signature_index() const { return _signature_index; } 222 void set_signature_index(int index) { _signature_index = index; } 223 224 // generics support 225 int generic_signature_index() const { return _generic_signature_index; } 226 void set_generic_signature_index(int index) { _generic_signature_index = index; } 227 228 // Sizing 229 static int header_size() { 230 return sizeof(constMethodOopDesc)/HeapWordSize; 231 } 232 233 // Object size needed 234 static int object_size(int code_size, int compressed_line_number_size, 235 int local_variable_table_length, 236 int checked_exceptions_length); 237 238 int object_size() const { return _constMethod_size; } 239 void set_constMethod_size(int size) { _constMethod_size = size; } 240 // Is object parsable by gc 241 bool object_is_parsable() { return object_size() > 0; } 242 243 // code size 244 int code_size() const { return _code_size; } 245 void set_code_size(int size) { 246 assert(max_method_code_size < (1 << 16), 247 "u2 is too small to hold method code size in general"); 248 assert(0 <= size && size <= max_method_code_size, "invalid code size"); 249 _code_size = size; 250 } 251 252 // linenumber table - note that length is unknown until decompression, 253 // see class CompressedLineNumberReadStream. 254 u_char* compressed_linenumber_table() const; // not preserved by gc 255 u2* checked_exceptions_length_addr() const; 256 u2* localvariable_table_length_addr() const; 257 258 // checked exceptions 259 int checked_exceptions_length() const; 260 CheckedExceptionElement* checked_exceptions_start() const; 261 262 // localvariable table 263 int localvariable_table_length() const; 264 LocalVariableTableElement* localvariable_table_start() const; 265 266 // byte codes 267 void set_code(address code) { 268 if (code_size() > 0) { 269 memcpy(code_base(), code, code_size()); 270 } 271 } 272 address code_base() const { return (address) (this+1); } 273 address code_end() const { return code_base() + code_size(); } 274 bool contains(address bcp) const { return code_base() <= bcp 275 && bcp < code_end(); } 276 // Offset to bytecodes 277 static ByteSize codes_offset() 278 { return in_ByteSize(sizeof(constMethodOopDesc)); } 279 280 // interpreter support 281 static ByteSize exception_table_offset() 282 { return byte_offset_of(constMethodOopDesc, _exception_table); } 283 284 // Garbage collection support 285 oop* adr_method() const { return (oop*)&_method; } 286 oop* adr_stackmap_data() const { return (oop*)&_stackmap_data; } 287 oop* adr_exception_table() const { return (oop*)&_exception_table; } 288 bool is_conc_safe() { return _is_conc_safe; } 289 void set_is_conc_safe(bool v) { _is_conc_safe = v; } 290 291 // Unique id for the method 292 static const u2 MAX_IDNUM; 293 static const u2 UNSET_IDNUM; 294 u2 method_idnum() const { return _method_idnum; } 295 void set_method_idnum(u2 idnum) { _method_idnum = idnum; } 296 297 private: 298 // Since the size of the compressed line number table is unknown, the 299 // offsets of the other variable sized sections are computed backwards 300 // from the end of the constMethodOop. 301 302 // First byte after constMethodOop 303 address constMethod_end() const 304 { return (address)((oop*)this + _constMethod_size); } 305 306 // Last short in constMethodOop 307 u2* last_u2_element() const 308 { return (u2*)constMethod_end() - 1; } 309 }; 310 311 #endif // SHARE_VM_OOPS_CONSTMETHODOOP_HPP