1 /*
2 * Copyright (c) 1999, 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_CI_CISTREAMS_HPP
26 #define SHARE_VM_CI_CISTREAMS_HPP
27
28 #include "ci/ciClassList.hpp"
29 #include "ci/ciExceptionHandler.hpp"
30 #include "ci/ciInstanceKlass.hpp"
31 #include "ci/ciMethod.hpp"
32 #include "interpreter/bytecode.hpp"
33
34 // ciBytecodeStream
35 //
36 // The class is used to iterate over the bytecodes of a method.
37 // It hides the details of constant pool structure/access by
38 // providing accessors for constant pool items. It returns only pure
39 // Java bytecodes; VM-internal _fast bytecodes are translated back to
40 // their original form during iteration.
41 class ciBytecodeStream : StackObj {
42 private:
43 // Handling for the weird bytecodes
44 Bytecodes::Code next_wide_or_table(Bytecodes::Code); // Handle _wide & complicated inline table
45
46 static Bytecodes::Code check_java(Bytecodes::Code c) {
47 assert(Bytecodes::is_java_code(c), "should not return _fast bytecodes");
48 return c;
49 }
50
51 static Bytecodes::Code check_defined(Bytecodes::Code c) {
52 assert(Bytecodes::is_defined(c), "");
53 return c;
54 }
55
56 ciMethod* _method; // the method
57 ciInstanceKlass* _holder;
58 ciCPCache* _cpcache;
59 address _bc_start; // Start of current bytecode for table
60 address _was_wide; // Address past last wide bytecode
61 jint* _table_base; // Aligned start of last table or switch
62
63 address _start; // Start of bytecodes
64 address _end; // Past end of bytecodes
65 address _pc; // Current PC
66 Bytecodes::Code _bc; // Current bytecode
67 Bytecodes::Code _raw_bc; // Current bytecode, raw form
68
69 void reset( address base, unsigned int size ) {
70 _bc_start =_was_wide = 0;
71 _start = _pc = base; _end = base + size;
72 _cpcache = NULL;
73 }
74
75 void assert_wide(bool require_wide) const {
76 if (require_wide)
77 { assert(is_wide(), "must be a wide instruction"); }
78 else { assert(!is_wide(), "must not be a wide instruction"); }
79 }
80
81 Bytecode* bytecode() const { return Bytecode_at(_bc_start); }
82 Bytecode* next_bytecode() const { return Bytecode_at(_pc); }
83
84 public:
85 // End-Of-Bytecodes
86 static Bytecodes::Code EOBC() {
87 return Bytecodes::_illegal;
88 }
89
90 ciBytecodeStream(ciMethod* m) {
91 reset_to_method(m);
92 }
93
94 ciBytecodeStream() {
95 reset_to_method(NULL);
96 }
97
98 ciMethod* method() const { return _method; }
99
100 void reset_to_method(ciMethod* m) {
101 _method = m;
102 if (m == NULL) {
103 _holder = NULL;
104 reset(NULL, 0);
105 } else {
106 _holder = m->holder();
107 reset(m->code(), m->code_size());
108 }
109 }
110
111 void reset_to_bci( int bci );
112
113 // Force the iterator to report a certain bci.
114 void force_bci(int bci);
115
116 void set_max_bci( int max ) {
117 _end = _start + max;
118 }
119
120 address cur_bcp() const { return _bc_start; } // Returns bcp to current instruction
121 int next_bci() const { return _pc - _start; }
122 int cur_bci() const { return _bc_start - _start; }
123 int instruction_size() const { return _pc - _bc_start; }
124
125 Bytecodes::Code cur_bc() const{ return check_java(_bc); }
126 Bytecodes::Code cur_bc_raw() const { return check_defined(_raw_bc); }
127 Bytecodes::Code next_bc() { return Bytecodes::java_code((Bytecodes::Code)* _pc); }
128
129 // Return current ByteCode and increment PC to next bytecode, skipping all
130 // intermediate constants. Returns EOBC at end.
131 // Expected usage:
132 // while( (bc = iter.next()) != EOBC() ) { ... }
133 Bytecodes::Code next() {
134 _bc_start = _pc; // Capture start of bc
135 if( _pc >= _end ) return EOBC(); // End-Of-Bytecodes
136
137 // Fetch Java bytecode
138 // All rewritten bytecodes maintain the size of original bytecode.
139 _bc = Bytecodes::java_code(_raw_bc = (Bytecodes::Code)*_pc);
140 int csize = Bytecodes::length_for(_bc); // Expected size
141 _pc += csize; // Bump PC past bytecode
142 if (csize == 0) {
143 _bc = next_wide_or_table(_bc);
144 }
145 return check_java(_bc);
146 }
147
148 bool is_wide() const { return ( _pc == _was_wide ); }
149
150 // Does this instruction contain an index which refes into the CP cache?
151 bool has_cache_index() const { return Bytecodes::uses_cp_cache(cur_bc_raw()); }
152
153 int get_index_u1() const {
154 return bytecode()->get_index_u1(cur_bc_raw());
155 }
156
157 int get_index_u1_cpcache() const {
158 return bytecode()->get_index_u1_cpcache(cur_bc_raw());
159 }
160
161 // Get a byte index following this bytecode.
162 // If prefixed with a wide bytecode, get a wide index.
163 int get_index() const {
164 assert(!has_cache_index(), "else use cpcache variant");
165 return (_pc == _was_wide) // was widened?
166 ? get_index_u2(true) // yes, return wide index
167 : get_index_u1(); // no, return narrow index
168 }
169
170 // Get 2-byte index (byte swapping depending on which bytecode)
171 int get_index_u2(bool is_wide = false) const {
172 return bytecode()->get_index_u2(cur_bc_raw(), is_wide);
173 }
174
175 // Get 2-byte index in native byte order. (Rewriter::rewrite makes these.)
176 int get_index_u2_cpcache() const {
177 return bytecode()->get_index_u2_cpcache(cur_bc_raw());
178 }
179
180 // Get 4-byte index, for invokedynamic.
181 int get_index_u4() const {
182 return bytecode()->get_index_u4(cur_bc_raw());
183 }
184
185 bool has_index_u4() const {
186 return bytecode()->has_index_u4(cur_bc_raw());
187 }
188
189 // Get dimensions byte (multinewarray)
190 int get_dimensions() const { return *(unsigned char*)(_pc-1); }
191
192 // Sign-extended index byte/short, no widening
193 int get_constant_u1() const { return bytecode()->get_constant_u1(instruction_size()-1, cur_bc_raw()); }
194 int get_constant_u2(bool is_wide = false) const { return bytecode()->get_constant_u2(instruction_size()-2, cur_bc_raw(), is_wide); }
195
196 // Get a byte signed constant for "iinc". Invalid for other bytecodes.
197 // If prefixed with a wide bytecode, get a wide constant
198 int get_iinc_con() const {return (_pc==_was_wide) ? (jshort) get_constant_u2(true) : (jbyte) get_constant_u1();}
199
200 // 2-byte branch offset from current pc
201 int get_dest() const {
202 return cur_bci() + bytecode()->get_offset_s2(cur_bc_raw());
203 }
204
205 // 2-byte branch offset from next pc
206 int next_get_dest() const {
207 assert(_pc < _end, "");
208 return next_bci() + next_bytecode()->get_offset_s2(Bytecodes::_ifeq);
209 }
210
211 // 4-byte branch offset from current pc
212 int get_far_dest() const {
213 return cur_bci() + bytecode()->get_offset_s4(cur_bc_raw());
214 }
215
216 // For a lookup or switch table, return target destination
217 int get_int_table( int index ) const {
218 return Bytes::get_Java_u4((address)&_table_base[index]); }
219
220 // For tableswitch - get length of offset part
221 int get_tableswitch_length() { return get_int_table(2)-get_int_table(1)+1; }
222
223 int get_dest_table( int index ) const {
224 return cur_bci() + get_int_table(index); }
225
226 // --- Constant pool access ---
227 int get_constant_raw_index() const;
228 int get_constant_pool_index() const;
229 int get_constant_cache_index() const;
230 int get_field_index();
231 int get_method_index();
232
233 // If this bytecode is a new, newarray, multianewarray, instanceof,
234 // or checkcast, get the referenced klass.
235 ciKlass* get_klass(bool& will_link);
236 int get_klass_index() const;
237
238 // If this bytecode is one of the ldc variants, get the referenced
239 // constant. Do not attempt to resolve it, since that would require
240 // execution of Java code. If it is not resolved, return an unloaded
241 // object (ciConstant.as_object()->is_loaded() == false).
242 ciConstant get_constant();
243 constantTag get_constant_pool_tag(int index) const;
244
245 // True if the klass-using bytecode points to an unresolved klass
246 bool is_unresolved_klass() const {
247 constantTag tag = get_constant_pool_tag(get_klass_index());
248 return tag.is_unresolved_klass();
249 }
250
251 // If this bytecode is one of get_field, get_static, put_field,
252 // or put_static, get the referenced field.
253 ciField* get_field(bool& will_link);
254
255 ciInstanceKlass* get_declared_field_holder();
256 int get_field_holder_index();
257 int get_field_signature_index();
258
259 // If this is a method invocation bytecode, get the invoked method.
260 ciMethod* get_method(bool& will_link);
261 ciKlass* get_declared_method_holder();
262 int get_method_holder_index();
263 int get_method_signature_index();
264
265 ciCPCache* get_cpcache() const;
266 ciCallSite* get_call_site();
267 };
268
269
270 // ciSignatureStream
271 //
272 // The class is used to iterate over the elements of a method signature.
273 class ciSignatureStream : public StackObj {
274 private:
275 ciSignature* _sig;
276 int _pos;
277 public:
278 ciSignatureStream(ciSignature* signature) {
279 _sig = signature;
280 _pos = 0;
281 }
282
283 bool at_return_type() { return _pos == _sig->count(); }
284
285 bool is_done() { return _pos > _sig->count(); }
286
287 void next() {
288 if (_pos <= _sig->count()) {
289 _pos++;
290 }
291 }
292
293 ciType* type() {
294 if (at_return_type()) {
295 return _sig->return_type();
296 } else {
297 return _sig->type_at(_pos);
298 }
299 }
300 };
301
302
303 // ciExceptionHandlerStream
304 //
305 // The class is used to iterate over the exception handlers of
306 // a method.
307 class ciExceptionHandlerStream : public StackObj {
308 private:
309 // The method whose handlers we are traversing
310 ciMethod* _method;
311
312 // Our current position in the list of handlers
313 int _pos;
314 int _end;
315
316 ciInstanceKlass* _exception_klass;
317 int _bci;
318 bool _is_exact;
319
320 public:
321 ciExceptionHandlerStream(ciMethod* method) {
322 _method = method;
323
324 // Force loading of method code and handlers.
325 _method->code();
326
327 _pos = 0;
328 _end = _method->_handler_count;
329 _exception_klass = NULL;
330 _bci = -1;
331 _is_exact = false;
332 }
333
334 ciExceptionHandlerStream(ciMethod* method, int bci,
335 ciInstanceKlass* exception_klass = NULL,
336 bool is_exact = false) {
337 _method = method;
338
339 // Force loading of method code and handlers.
340 _method->code();
341
342 _pos = -1;
343 _end = _method->_handler_count + 1; // include the rethrow handler
344 _exception_klass = (exception_klass != NULL && exception_klass->is_loaded()
345 ? exception_klass
346 : NULL);
347 _bci = bci;
348 assert(_bci >= 0, "bci out of range");
349 _is_exact = is_exact;
350 next();
351 }
352
353 // These methods are currently implemented in an odd way.
354 // Count the number of handlers the iterator has ever produced
355 // or will ever produce. Do not include the final rethrow handler.
356 // That is, a trivial exception handler stream will have a count
357 // of zero and produce just the rethrow handler.
358 int count();
359
360 // Count the number of handlers this stream will produce from now on.
361 // Include the current handler, and the final rethrow handler.
362 // The remaining count will be zero iff is_done() is true,
363 int count_remaining();
364
365 bool is_done() {
366 return (_pos >= _end);
367 }
368
369 void next() {
370 _pos++;
371 if (_bci != -1) {
372 // We are not iterating over all handlers...
373 while (!is_done()) {
374 ciExceptionHandler* handler = _method->_exception_handlers[_pos];
375 if (handler->is_in_range(_bci)) {
376 if (handler->is_catch_all()) {
377 // Found final active catch block.
378 _end = _pos+1;
379 return;
380 } else if (_exception_klass == NULL || !handler->catch_klass()->is_loaded()) {
381 // We cannot do any type analysis here. Must conservatively assume
382 // catch block is reachable.
383 return;
384 } else if (_exception_klass->is_subtype_of(handler->catch_klass())) {
385 // This catch clause will definitely catch the exception.
386 // Final candidate.
387 _end = _pos+1;
388 return;
389 } else if (!_is_exact &&
390 handler->catch_klass()->is_subtype_of(_exception_klass)) {
391 // This catch block may be reachable.
392 return;
393 }
394 }
395
396 // The catch block was not pertinent. Go on.
397 _pos++;
398 }
399 } else {
400 // This is an iteration over all handlers.
401 return;
402 }
403 }
404
405 ciExceptionHandler* handler() {
406 return _method->_exception_handlers[_pos];
407 }
408 };
409
410 #endif // SHARE_VM_CI_CISTREAMS_HPP