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comparison src/share/vm/ci/ciStreams.hpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 1999-2005 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 // ciBytecodeStream
26 //
27 // The class is used to iterate over the bytecodes of a method.
28 // It hides the details of constant pool structure/access by
29 // providing accessors for constant pool items. It returns only pure
30 // Java bytecodes; VM-internal _fast bytecodes are translated back to
31 // their original form during iteration.
32 class ciBytecodeStream : StackObj {
33 private:
34 // Handling for the weird bytecodes
35 Bytecodes::Code wide(); // Handle wide bytecode
36 Bytecodes::Code table(Bytecodes::Code); // Handle complicated inline table
37
38 static Bytecodes::Code check_java(Bytecodes::Code c) {
39 assert(Bytecodes::is_java_code(c), "should not return _fast bytecodes");
40 return c;
41 }
42
43 ciMethod* _method; // the method
44 ciInstanceKlass* _holder;
45 address _bc_start; // Start of current bytecode for table
46 address _was_wide; // Address past last wide bytecode
47 jint* _table_base; // Aligned start of last table or switch
48
49 address _start; // Start of bytecodes
50 address _end; // Past end of bytecodes
51 address _pc; // Current PC
52 Bytecodes::Code _bc; // Current bytecode
53
54 void reset( address base, unsigned int size ) {
55 _bc_start =_was_wide = 0;
56 _start = _pc = base; _end = base + size; }
57
58 public:
59 // End-Of-Bytecodes
60 static Bytecodes::Code EOBC() {
61 return Bytecodes::_illegal;
62 }
63
64 ciBytecodeStream(ciMethod* m) {
65 reset_to_method(m);
66 }
67
68 ciBytecodeStream() {
69 reset_to_method(NULL);
70 }
71
72 ciMethod* method() const { return _method; }
73
74 void reset_to_method(ciMethod* m) {
75 _method = m;
76 if (m == NULL) {
77 _holder = NULL;
78 reset(NULL, 0);
79 } else {
80 _holder = m->holder();
81 reset(m->code(), m->code_size());
82 }
83 }
84
85 void reset_to_bci( int bci );
86
87 // Force the iterator to report a certain bci.
88 void force_bci(int bci);
89
90 void set_max_bci( int max ) {
91 _end = _start + max;
92 }
93
94 address cur_bcp() { return _bc_start; } // Returns bcp to current instruction
95 int next_bci() const { return _pc -_start; }
96 int cur_bci() const { return _bc_start - _start; }
97
98 Bytecodes::Code cur_bc() const{ return check_java(_bc); }
99 Bytecodes::Code next_bc() { return Bytecodes::java_code((Bytecodes::Code)* _pc); }
100
101 // Return current ByteCode and increment PC to next bytecode, skipping all
102 // intermediate constants. Returns EOBC at end.
103 // Expected usage:
104 // while( (bc = iter.next()) != EOBC() ) { ... }
105 Bytecodes::Code next() {
106 _bc_start = _pc; // Capture start of bc
107 if( _pc >= _end ) return EOBC(); // End-Of-Bytecodes
108
109 // Fetch Java bytecode
110 // All rewritten bytecodes maintain the size of original bytecode.
111 _bc = Bytecodes::java_code((Bytecodes::Code)*_pc);
112 int csize = Bytecodes::length_for(_bc); // Expected size
113
114 if( _bc == Bytecodes::_wide ) {
115 _bc=wide(); // Handle wide bytecode
116 } else if( csize == 0 ) {
117 _bc=table(_bc); // Handle inline tables
118 } else {
119 _pc += csize; // Bump PC past bytecode
120 }
121 return check_java(_bc);
122 }
123
124 bool is_wide() { return ( _pc == _was_wide ); }
125
126 // Get a byte index following this bytecode.
127 // If prefixed with a wide bytecode, get a wide index.
128 int get_index() const {
129 return (_pc == _was_wide) // was widened?
130 ? Bytes::get_Java_u2(_bc_start+2) // yes, return wide index
131 : _bc_start[1]; // no, return narrow index
132 }
133
134 // Set a byte index following this bytecode.
135 // If prefixed with a wide bytecode, get a wide index.
136 void put_index(int idx) {
137 if (_pc == _was_wide) // was widened?
138 Bytes::put_Java_u2(_bc_start+2,idx); // yes, set wide index
139 else
140 _bc_start[1]=idx; // no, set narrow index
141 }
142
143 // Get 2-byte index (getfield/putstatic/etc)
144 int get_index_big() const { return Bytes::get_Java_u2(_bc_start+1); }
145
146 // Get dimensions byte (multinewarray)
147 int get_dimensions() const { return *(unsigned char*)(_pc-1); }
148
149 // Get unsigned index fast
150 int get_index_fast() const { return Bytes::get_native_u2(_pc-2); }
151
152 // Sign-extended index byte/short, no widening
153 int get_byte() const { return (int8_t)(_pc[-1]); }
154 int get_short() const { return (int16_t)Bytes::get_Java_u2(_pc-2); }
155 int get_long() const { return (int32_t)Bytes::get_Java_u4(_pc-4); }
156
157 // Get a byte signed constant for "iinc". Invalid for other bytecodes.
158 // If prefixed with a wide bytecode, get a wide constant
159 int get_iinc_con() const {return (_pc==_was_wide) ? get_short() :get_byte();}
160
161 // 2-byte branch offset from current pc
162 int get_dest( ) const {
163 assert( Bytecodes::length_at(_bc_start) == sizeof(jshort)+1, "get_dest called with bad bytecode" );
164 return _bc_start-_start + (short)Bytes::get_Java_u2(_pc-2);
165 }
166
167 // 2-byte branch offset from next pc
168 int next_get_dest( ) const {
169 address next_bc_start = _pc;
170 assert( _pc < _end, "" );
171 Bytecodes::Code next_bc = (Bytecodes::Code)*_pc;
172 assert( next_bc != Bytecodes::_wide, "");
173 int next_csize = Bytecodes::length_for(next_bc);
174 assert( next_csize != 0, "" );
175 assert( next_bc <= Bytecodes::_jsr_w, "");
176 address next_pc = _pc + next_csize;
177 assert( Bytecodes::length_at(next_bc_start) == sizeof(jshort)+1, "next_get_dest called with bad bytecode" );
178 return next_bc_start-_start + (short)Bytes::get_Java_u2(next_pc-2);
179 }
180
181 // 4-byte branch offset from current pc
182 int get_far_dest( ) const {
183 assert( Bytecodes::length_at(_bc_start) == sizeof(jint)+1, "dest4 called with bad bytecode" );
184 return _bc_start-_start + (int)Bytes::get_Java_u4(_pc-4);
185 }
186
187 // For a lookup or switch table, return target destination
188 int get_int_table( int index ) const {
189 return Bytes::get_Java_u4((address)&_table_base[index]); }
190
191 // For tableswitch - get length of offset part
192 int get_tableswitch_length() { return get_int_table(2)-get_int_table(1)+1; }
193
194 int get_dest_table( int index ) const {
195 return cur_bci() + get_int_table(index); }
196
197 // --- Constant pool access ---
198 int get_constant_index() const;
199 int get_field_index();
200 int get_method_index();
201
202 // If this bytecode is a new, newarray, multianewarray, instanceof,
203 // or checkcast, get the referenced klass.
204 ciKlass* get_klass(bool& will_link);
205 int get_klass_index() const;
206
207 // If this bytecode is one of the ldc variants, get the referenced
208 // constant
209 ciConstant get_constant();
210 // True if the ldc variant points to an unresolved string
211 bool is_unresolved_string() const;
212 // True if the ldc variant points to an unresolved klass
213 bool is_unresolved_klass() const;
214
215 // If this bytecode is one of get_field, get_static, put_field,
216 // or put_static, get the referenced field.
217 ciField* get_field(bool& will_link);
218
219 ciInstanceKlass* get_declared_field_holder();
220 int get_field_holder_index();
221 int get_field_signature_index();
222
223 // If this is a method invocation bytecode, get the invoked method.
224 ciMethod* get_method(bool& will_link);
225 ciKlass* get_declared_method_holder();
226 int get_method_holder_index();
227 int get_method_signature_index();
228 };
229
230
231 // ciSignatureStream
232 //
233 // The class is used to iterate over the elements of a method signature.
234 class ciSignatureStream : public StackObj {
235 private:
236 ciSignature* _sig;
237 int _pos;
238 public:
239 ciSignatureStream(ciSignature* signature) {
240 _sig = signature;
241 _pos = 0;
242 }
243
244 bool at_return_type() { return _pos == _sig->count(); }
245
246 bool is_done() { return _pos > _sig->count(); }
247
248 void next() {
249 if (_pos <= _sig->count()) {
250 _pos++;
251 }
252 }
253
254 ciType* type() {
255 if (at_return_type()) {
256 return _sig->return_type();
257 } else {
258 return _sig->type_at(_pos);
259 }
260 }
261 };
262
263
264 // ciExceptionHandlerStream
265 //
266 // The class is used to iterate over the exception handlers of
267 // a method.
268 class ciExceptionHandlerStream : public StackObj {
269 private:
270 // The method whose handlers we are traversing
271 ciMethod* _method;
272
273 // Our current position in the list of handlers
274 int _pos;
275 int _end;
276
277 ciInstanceKlass* _exception_klass;
278 int _bci;
279 bool _is_exact;
280
281 public:
282 ciExceptionHandlerStream(ciMethod* method) {
283 _method = method;
284
285 // Force loading of method code and handlers.
286 _method->code();
287
288 _pos = 0;
289 _end = _method->_handler_count;
290 _exception_klass = NULL;
291 _bci = -1;
292 _is_exact = false;
293 }
294
295 ciExceptionHandlerStream(ciMethod* method, int bci,
296 ciInstanceKlass* exception_klass = NULL,
297 bool is_exact = false) {
298 _method = method;
299
300 // Force loading of method code and handlers.
301 _method->code();
302
303 _pos = -1;
304 _end = _method->_handler_count + 1; // include the rethrow handler
305 _exception_klass = (exception_klass != NULL && exception_klass->is_loaded()
306 ? exception_klass
307 : NULL);
308 _bci = bci;
309 assert(_bci >= 0, "bci out of range");
310 _is_exact = is_exact;
311 next();
312 }
313
314 // These methods are currently implemented in an odd way.
315 // Count the number of handlers the iterator has ever produced
316 // or will ever produce. Do not include the final rethrow handler.
317 // That is, a trivial exception handler stream will have a count
318 // of zero and produce just the rethrow handler.
319 int count();
320
321 // Count the number of handlers this stream will produce from now on.
322 // Include the current handler, and the final rethrow handler.
323 // The remaining count will be zero iff is_done() is true,
324 int count_remaining();
325
326 bool is_done() {
327 return (_pos >= _end);
328 }
329
330 void next() {
331 _pos++;
332 if (_bci != -1) {
333 // We are not iterating over all handlers...
334 while (!is_done()) {
335 ciExceptionHandler* handler = _method->_exception_handlers[_pos];
336 if (handler->is_in_range(_bci)) {
337 if (handler->is_catch_all()) {
338 // Found final active catch block.
339 _end = _pos+1;
340 return;
341 } else if (_exception_klass == NULL || !handler->catch_klass()->is_loaded()) {
342 // We cannot do any type analysis here. Must conservatively assume
343 // catch block is reachable.
344 return;
345 } else if (_exception_klass->is_subtype_of(handler->catch_klass())) {
346 // This catch clause will definitely catch the exception.
347 // Final candidate.
348 _end = _pos+1;
349 return;
350 } else if (!_is_exact &&
351 handler->catch_klass()->is_subtype_of(_exception_klass)) {
352 // This catch block may be reachable.
353 return;
354 }
355 }
356
357 // The catch block was not pertinent. Go on.
358 _pos++;
359 }
360 } else {
361 // This is an iteration over all handlers.
362 return;
363 }
364 }
365
366 ciExceptionHandler* handler() {
367 return _method->_exception_handlers[_pos];
368 }
369 };