1 /*
2 * Copyright (c) 2003, 2016, 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 u1 _result_type; // BasicType of result
143
144 // Size of Java bytecodes allocated immediately after methodOop.
145 u2 _code_size;
146 u2 _name_index; // Method name (index in constant pool)
147 u2 _signature_index; // Method signature (index in constant pool)
148 u2 _method_idnum; // unique identification number for the method within the class
149 // initially corresponds to the index into the methods array.
150 // but this may change with redefinition
151 u2 _generic_signature_index; // Generic signature (index in constant pool, 0 if absent)
152
153 public:
154 // Inlined tables
155 void set_inlined_tables_length(int checked_exceptions_len,
156 int compressed_line_number_size,
157 int localvariable_table_len);
158
159 bool has_linenumber_table() const
160 { return (_flags & _has_linenumber_table) != 0; }
161
162 bool has_checked_exceptions() const
163 { return (_flags & _has_checked_exceptions) != 0; }
164
165 bool has_localvariable_table() const
166 { return (_flags & _has_localvariable_table) != 0; }
167
168 void set_interpreter_kind(int kind) { _interpreter_kind = kind; }
169 int interpreter_kind(void) const { return _interpreter_kind; }
170
171 // backpointer to non-const methodOop
172 methodOop method() const { return _method; }
173 void set_method(methodOop m) { oop_store_without_check((oop*)&_method, (oop) m); }
174
175
176 // stackmap table data
177 typeArrayOop stackmap_data() const { return _stackmap_data; }
178 void set_stackmap_data(typeArrayOop sd) {
179 oop_store_without_check((oop*)&_stackmap_data, (oop)sd);
180 }
181 bool has_stackmap_table() const { return _stackmap_data != NULL; }
182
183 // exception handler table
184 typeArrayOop exception_table() const { return _exception_table; }
185 void set_exception_table(typeArrayOop e) { oop_store_without_check((oop*) &_exception_table, (oop) e); }
186 bool has_exception_handler() const { return exception_table() != NULL && exception_table()->length() > 0; }
187
188 void init_fingerprint() {
189 const uint64_t initval = CONST64(0x8000000000000000);
190 _fingerprint = initval;
191 }
192
193 uint64_t fingerprint() const {
194 // Since reads aren't atomic for 64 bits, if any of the high or low order
195 // word is the initial value, return 0. See init_fingerprint for initval.
196 uint high_fp = (uint)(_fingerprint >> 32);
197 if ((int) _fingerprint == 0 || high_fp == 0x80000000) {
198 return 0L;
199 } else {
200 return _fingerprint;
201 }
202 }
203
204 uint64_t set_fingerprint(uint64_t new_fingerprint) {
205 #ifdef ASSERT
206 // Assert only valid if complete/valid 64 bit _fingerprint value is read.
207 uint64_t oldfp = fingerprint();
208 #endif // ASSERT
209 _fingerprint = new_fingerprint;
210 assert(oldfp == 0L || new_fingerprint == oldfp,
211 "fingerprint cannot change");
212 assert(((new_fingerprint >> 32) != 0x80000000) && (int)new_fingerprint !=0,
213 "fingerprint should call init to set initial value");
214 return new_fingerprint;
215 }
216
217 // name
218 int name_index() const { return _name_index; }
219 void set_name_index(int index) { _name_index = index; }
220
221 // signature
222 int signature_index() const { return _signature_index; }
223 void set_signature_index(int index) { _signature_index = index; }
224
225 // generics support
226 int generic_signature_index() const { return _generic_signature_index; }
227 void set_generic_signature_index(int index) { _generic_signature_index = index; }
228
229 // Sizing
230 static int header_size() {
231 return sizeof(constMethodOopDesc)/HeapWordSize;
232 }
233
234 // Object size needed
235 static int object_size(int code_size, int compressed_line_number_size,
236 int local_variable_table_length,
237 int checked_exceptions_length);
238
239 int object_size() const { return _constMethod_size; }
240 void set_constMethod_size(int size) { _constMethod_size = size; }
241 // Is object parsable by gc
242 bool object_is_parsable() { return object_size() > 0; }
243
244 // code size
245 int code_size() const { return _code_size; }
246 void set_code_size(int size) {
247 assert(max_method_code_size < (1 << 16),
248 "u2 is too small to hold method code size in general");
249 assert(0 <= size && size <= max_method_code_size, "invalid code size");
250 _code_size = size;
251 }
252
253 // linenumber table - note that length is unknown until decompression,
254 // see class CompressedLineNumberReadStream.
255 u_char* compressed_linenumber_table() const; // not preserved by gc
256 u2* checked_exceptions_length_addr() const;
257 u2* localvariable_table_length_addr() const;
258
259 // checked exceptions
260 int checked_exceptions_length() const;
261 CheckedExceptionElement* checked_exceptions_start() const;
262
263 // localvariable table
264 int localvariable_table_length() const;
265 LocalVariableTableElement* localvariable_table_start() const;
266
267 // byte codes
268 void set_code(address code) {
269 if (code_size() > 0) {
270 memcpy(code_base(), code, code_size());
271 }
272 }
273 address code_base() const { return (address) (this+1); }
274 address code_end() const { return code_base() + code_size(); }
275 bool contains(address bcp) const { return code_base() <= bcp
276 && bcp < code_end(); }
277 // Offset to bytecodes
278 static ByteSize codes_offset()
279 { return in_ByteSize(sizeof(constMethodOopDesc)); }
280
281 // interpreter support
282 static ByteSize exception_table_offset()
283 { return byte_offset_of(constMethodOopDesc, _exception_table); }
284 static ByteSize result_type_offset()
285 { return byte_offset_of(constMethodOopDesc, _result_type); }
286 void set_result_type(BasicType rt) { assert(rt < 16, "result type too large");
287 _result_type = (u1)rt; }
288
289 // Garbage collection support
290 oop* adr_method() const { return (oop*)&_method; }
291 oop* adr_stackmap_data() const { return (oop*)&_stackmap_data; }
292 oop* adr_exception_table() const { return (oop*)&_exception_table; }
293 bool is_conc_safe() { return _is_conc_safe; }
294 void set_is_conc_safe(bool v) { _is_conc_safe = v; }
295
296 // Unique id for the method
297 static const u2 MAX_IDNUM;
298 static const u2 UNSET_IDNUM;
299 u2 method_idnum() const { return _method_idnum; }
300 void set_method_idnum(u2 idnum) { _method_idnum = idnum; }
301
302 private:
303 // Since the size of the compressed line number table is unknown, the
304 // offsets of the other variable sized sections are computed backwards
305 // from the end of the constMethodOop.
306
307 // First byte after constMethodOop
308 address constMethod_end() const
309 { return (address)((oop*)this + _constMethod_size); }
310
311 // Last short in constMethodOop
312 u2* last_u2_element() const
313 { return (u2*)constMethod_end() - 1; }
314 };
315
316 #endif // SHARE_VM_OOPS_CONSTMETHODOOP_HPP