1 /*
2 * Copyright (c) 2003, 2012, 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 // | constMethod_size |
47 // | interp_kind | flags | code_size |
48 // | name index | signature index |
49 // | method_idnum | generic_signature_index |
50 // |------------------------------------------------------|
51 // | |
52 // | byte codes |
53 // | |
54 // |------------------------------------------------------|
55 // | compressed linenumber table |
56 // | (see class CompressedLineNumberReadStream) |
57 // | (note that length is unknown until decompressed) |
58 // | (access flags bit tells whether table is present) |
59 // | (indexed from start of constMethodOop) |
60 // | (elements not necessarily sorted!) |
61 // |------------------------------------------------------|
62 // | localvariable table elements + length (length last) |
63 // | (length is u2, elements are 6-tuples of u2) |
64 // | (see class LocalVariableTableElement) |
65 // | (access flags bit tells whether table is present) |
66 // | (indexed from end of constMethodOop) |
67 // |------------------------------------------------------|
68 // | exception table + length (length last) |
69 // | (length is u2, elements are 4-tuples of u2) |
70 // | (see class ExceptionTableElement) |
71 // | (access flags bit tells whether table is present) |
72 // | (indexed from end of constMethodOop) |
73 // |------------------------------------------------------|
74 // | checked exceptions elements + length (length last) |
75 // | (length is u2, elements are u2) |
76 // | (see class CheckedExceptionElement) |
77 // | (access flags bit tells whether table is present) |
78 // | (indexed from end of constMethodOop) |
79 // |------------------------------------------------------|
80
81
82 // Utitily class decribing elements in checked exceptions table inlined in methodOop.
83 class CheckedExceptionElement VALUE_OBJ_CLASS_SPEC {
84 public:
85 u2 class_cp_index;
86 };
87
88
89 // Utitily class decribing elements in local variable table inlined in methodOop.
90 class LocalVariableTableElement VALUE_OBJ_CLASS_SPEC {
91 public:
92 u2 start_bci;
93 u2 length;
94 u2 name_cp_index;
95 u2 descriptor_cp_index;
96 u2 signature_cp_index;
97 u2 slot;
98 };
99
100
101 // Utitily class describing elements in exception table
102 class ExceptionTableElement VALUE_OBJ_CLASS_SPEC {
103 public:
104 u2 start_pc;
105 u2 end_pc;
106 u2 handler_pc;
107 u2 catch_type_index;
108 };
109
110 class constMethodOopDesc : public oopDesc {
111 friend class constMethodKlass;
112 friend class VMStructs;
113 private:
114 enum {
115 _has_linenumber_table = 1,
116 _has_checked_exceptions = 2,
117 _has_localvariable_table = 4,
118 _has_exception_table = 8
119 };
120
121 // Bit vector of signature
122 // Callers interpret 0=not initialized yet and
123 // -1=too many args to fix, must parse the slow way.
124 // The real initial value is special to account for nonatomicity of 64 bit
125 // loads and stores. This value may updated and read without a lock by
126 // multiple threads, so is volatile.
127 volatile uint64_t _fingerprint;
128 volatile bool _is_conc_safe; // if true, safe for concurrent GC processing
129
130 public:
131 oop* oop_block_beg() const { return adr_method(); }
132 oop* oop_block_end() const { return adr_stackmap_data() + 1; }
133
134 private:
135 //
136 // The oop block. See comment in klass.hpp before making changes.
137 //
138
139 // Backpointer to non-const methodOop (needed for some JVMTI operations)
140 methodOop _method;
141
142 // Raw stackmap data for the method
143 typeArrayOop _stackmap_data;
144
145 //
146 // End of the oop block.
147 //
148
149 int _constMethod_size;
150 jbyte _interpreter_kind;
151 jbyte _flags;
152
153 // Size of Java bytecodes allocated immediately after methodOop.
154 u2 _code_size;
155 u2 _name_index; // Method name (index in constant pool)
156 u2 _signature_index; // Method signature (index in constant pool)
157 u2 _method_idnum; // unique identification number for the method within the class
158 // initially corresponds to the index into the methods array.
159 // but this may change with redefinition
160 u2 _generic_signature_index; // Generic signature (index in constant pool, 0 if absent)
161
162 public:
163 // Inlined tables
164 void set_inlined_tables_length(int checked_exceptions_len,
165 int compressed_line_number_size,
166 int localvariable_table_len,
167 int exception_table_len);
168
169 bool has_linenumber_table() const
170 { return (_flags & _has_linenumber_table) != 0; }
171
172 bool has_checked_exceptions() const
173 { return (_flags & _has_checked_exceptions) != 0; }
174
175 bool has_localvariable_table() const
176 { return (_flags & _has_localvariable_table) != 0; }
177
178 bool has_exception_handler() const
179 { return (_flags & _has_exception_table) != 0; }
180
181 void set_interpreter_kind(int kind) { _interpreter_kind = kind; }
182 int interpreter_kind(void) const { return _interpreter_kind; }
183
184 // backpointer to non-const methodOop
185 methodOop method() const { return _method; }
186 void set_method(methodOop m) { oop_store_without_check((oop*)&_method, (oop) m); }
187
188
189 // stackmap table data
190 typeArrayOop stackmap_data() const { return _stackmap_data; }
191 void set_stackmap_data(typeArrayOop sd) {
192 oop_store_without_check((oop*)&_stackmap_data, (oop)sd);
193 }
194 bool has_stackmap_table() const { return _stackmap_data != NULL; }
195
196 void init_fingerprint() {
197 const uint64_t initval = CONST64(0x8000000000000000);
198 _fingerprint = initval;
199 }
200
201 uint64_t fingerprint() const {
202 // Since reads aren't atomic for 64 bits, if any of the high or low order
203 // word is the initial value, return 0. See init_fingerprint for initval.
204 uint high_fp = (uint)(_fingerprint >> 32);
205 if ((int) _fingerprint == 0 || high_fp == 0x80000000) {
206 return 0L;
207 } else {
208 return _fingerprint;
209 }
210 }
211
212 uint64_t set_fingerprint(uint64_t new_fingerprint) {
213 #ifdef ASSERT
214 // Assert only valid if complete/valid 64 bit _fingerprint value is read.
215 uint64_t oldfp = fingerprint();
216 #endif // ASSERT
217 _fingerprint = new_fingerprint;
218 assert(oldfp == 0L || new_fingerprint == oldfp,
219 "fingerprint cannot change");
220 assert(((new_fingerprint >> 32) != 0x80000000) && (int)new_fingerprint !=0,
221 "fingerprint should call init to set initial value");
222 return new_fingerprint;
223 }
224
225 // name
226 int name_index() const { return _name_index; }
227 void set_name_index(int index) { _name_index = index; }
228
229 // signature
230 int signature_index() const { return _signature_index; }
231 void set_signature_index(int index) { _signature_index = index; }
232
233 // generics support
234 int generic_signature_index() const { return _generic_signature_index; }
235 void set_generic_signature_index(int index) { _generic_signature_index = index; }
236
237 // Sizing
238 static int header_size() {
239 return sizeof(constMethodOopDesc)/HeapWordSize;
240 }
241
242 // Object size needed
243 static int object_size(int code_size, int compressed_line_number_size,
244 int local_variable_table_length,
245 int exception_table_length,
246 int checked_exceptions_length);
247
248 int object_size() const { return _constMethod_size; }
249 void set_constMethod_size(int size) { _constMethod_size = size; }
250 // Is object parsable by gc
251 bool object_is_parsable() { return object_size() > 0; }
252
253 // code size
254 int code_size() const { return _code_size; }
255 void set_code_size(int size) {
256 assert(max_method_code_size < (1 << 16),
257 "u2 is too small to hold method code size in general");
258 assert(0 <= size && size <= max_method_code_size, "invalid code size");
259 _code_size = size;
260 }
261
262 // linenumber table - note that length is unknown until decompression,
263 // see class CompressedLineNumberReadStream.
264 u_char* compressed_linenumber_table() const; // not preserved by gc
265 u2* checked_exceptions_length_addr() const;
266 u2* localvariable_table_length_addr() const;
267 u2* exception_table_length_addr() const;
268
269 // checked exceptions
270 int checked_exceptions_length() const;
271 CheckedExceptionElement* checked_exceptions_start() const;
272
273 // localvariable table
274 int localvariable_table_length() const;
275 LocalVariableTableElement* localvariable_table_start() const;
276
277 // exception table
278 int exception_table_length() const;
279 ExceptionTableElement* exception_table_start() const;
280
281 // byte codes
282 void set_code(address code) {
283 if (code_size() > 0) {
284 memcpy(code_base(), code, code_size());
285 }
286 }
287 address code_base() const { return (address) (this+1); }
288 address code_end() const { return code_base() + code_size(); }
289 bool contains(address bcp) const { return code_base() <= bcp
290 && bcp < code_end(); }
291 // Offset to bytecodes
292 static ByteSize codes_offset()
293 { return in_ByteSize(sizeof(constMethodOopDesc)); }
294
295 // Garbage collection support
296 oop* adr_method() const { return (oop*)&_method; }
297 oop* adr_stackmap_data() const { return (oop*)&_stackmap_data; }
298 bool is_conc_safe() { return _is_conc_safe; }
299 void set_is_conc_safe(bool v) { _is_conc_safe = v; }
300
301 // Unique id for the method
302 static const u2 MAX_IDNUM;
303 static const u2 UNSET_IDNUM;
304 u2 method_idnum() const { return _method_idnum; }
305 void set_method_idnum(u2 idnum) { _method_idnum = idnum; }
306
307 private:
308 // Since the size of the compressed line number table is unknown, the
309 // offsets of the other variable sized sections are computed backwards
310 // from the end of the constMethodOop.
311
312 // First byte after constMethodOop
313 address constMethod_end() const
314 { return (address)((oop*)this + _constMethod_size); }
315
316 // Last short in constMethodOop
317 u2* last_u2_element() const
318 { return (u2*)constMethod_end() - 1; }
319 };
320
321 #endif // SHARE_VM_OOPS_CONSTMETHODOOP_HPP