1 /*
2 * Copyright (c) 1999, 2021, 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_CI_CISTREAMS_HPP
26 #define SHARE_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 address _bc_start; // Start of current bytecode for table
59 address _was_wide; // Address past last wide bytecode
60 jint* _table_base; // Aligned start of last table or switch
61
62 address _start; // Start of bytecodes
63 address _end; // Past end of bytecodes
64 address _pc; // Current PC
65 Bytecodes::Code _bc; // Current bytecode
66 Bytecodes::Code _raw_bc; // Current bytecode, raw form
67
68 void reset( address base, unsigned int size ) {
69 _bc_start =_was_wide = 0;
70 _start = _pc = base; _end = base + size;
71 }
72
73 Bytecode bytecode() const { return Bytecode(this, _bc_start); }
74 Bytecode next_bytecode() const { return Bytecode(this, _pc); }
75
76 public:
77 // End-Of-Bytecodes
78 static Bytecodes::Code EOBC() {
79 return Bytecodes::_illegal;
80 }
81
82 ciBytecodeStream(ciMethod* m) {
83 reset_to_method(m);
84 }
85
86 ciBytecodeStream() {
87 reset_to_method(NULL);
88 }
89
90 ciMethod* method() const { return _method; }
91
92 void reset_to_method(ciMethod* m) {
93 _method = m;
94 if (m == NULL) {
95 _holder = NULL;
96 reset(NULL, 0);
97 } else {
98 _holder = m->holder();
99 reset(m->code(), m->code_size());
100 }
101 }
102
103 void reset_to_bci( int bci );
104
105 // Force the iterator to report a certain bci.
106 void force_bci(int bci);
107
108 void set_max_bci( int max ) {
109 _end = _start + max;
110 }
111
112 address cur_bcp() const { return _bc_start; } // Returns bcp to current instruction
113 int next_bci() const { return _pc - _start; }
114 int cur_bci() const { return _bc_start - _start; }
115 int instruction_size() const { return _pc - _bc_start; }
116
117 Bytecodes::Code cur_bc() const{ return check_java(_bc); }
118 Bytecodes::Code cur_bc_raw() const { return check_defined(_raw_bc); }
119 Bytecodes::Code next_bc() { return Bytecodes::java_code((Bytecodes::Code)* _pc); }
120
121 // Return current ByteCode and increment PC to next bytecode, skipping all
122 // intermediate constants. Returns EOBC at end.
123 // Expected usage:
124 // ciBytecodeStream iter(m);
125 // while (iter.next() != ciBytecodeStream::EOBC()) { ... }
126 Bytecodes::Code next() {
127 _bc_start = _pc; // Capture start of bc
128 if( _pc >= _end ) return EOBC(); // End-Of-Bytecodes
129
130 // Fetch Java bytecode
131 // All rewritten bytecodes maintain the size of original bytecode.
132 _bc = Bytecodes::java_code(_raw_bc = (Bytecodes::Code)*_pc);
133 int csize = Bytecodes::length_for(_bc); // Expected size
134 _pc += csize; // Bump PC past bytecode
135 if (csize == 0) {
136 _bc = next_wide_or_table(_bc);
137 }
138 return check_java(_bc);
139 }
140
141 bool is_wide() const { return ( _pc == _was_wide ); }
142
143 // Does this instruction contain an index which refes into the CP cache?
144 bool has_cache_index() const { return Bytecodes::uses_cp_cache(cur_bc_raw()); }
145
146 int get_index_u1() const {
147 return bytecode().get_index_u1(cur_bc_raw());
148 }
149
150 // Get a byte index following this bytecode.
151 // If prefixed with a wide bytecode, get a wide index.
152 int get_index() const {
153 assert(!has_cache_index(), "else use cpcache variant");
154 return (_pc == _was_wide) // was widened?
155 ? get_index_u2(true) // yes, return wide index
156 : get_index_u1(); // no, return narrow index
157 }
158
159 // Get 2-byte index (byte swapping depending on which bytecode)
160 int get_index_u2(bool is_wide = false) const {
161 return bytecode().get_index_u2(cur_bc_raw(), is_wide);
162 }
163
164 // Get 2-byte index in native byte order. (Rewriter::rewrite makes these.)
165 int get_index_u2_cpcache() const {
166 return bytecode().get_index_u2_cpcache(cur_bc_raw());
167 }
168
169 // Get 4-byte index, for invokedynamic.
170 int get_index_u4() const {
171 return bytecode().get_index_u4(cur_bc_raw());
172 }
173
174 bool has_index_u4() const {
175 return bytecode().has_index_u4(cur_bc_raw());
176 }
177
178 // Get dimensions byte (multinewarray)
179 int get_dimensions() const { return *(unsigned char*)(_pc-1); }
180
181 // Sign-extended index byte/short, no widening
182 int get_constant_u1() const { return bytecode().get_constant_u1(instruction_size()-1, cur_bc_raw()); }
183 int get_constant_u2(bool is_wide = false) const { return bytecode().get_constant_u2(instruction_size()-2, cur_bc_raw(), is_wide); }
184
185 // Get a byte signed constant for "iinc". Invalid for other bytecodes.
186 // If prefixed with a wide bytecode, get a wide constant
187 int get_iinc_con() const {return (_pc==_was_wide) ? (jshort) get_constant_u2(true) : (jbyte) get_constant_u1();}
188
189 // 2-byte branch offset from current pc
190 int get_dest() const {
191 return cur_bci() + bytecode().get_offset_s2(cur_bc_raw());
192 }
193
194 // 2-byte branch offset from next pc
195 int next_get_dest() const {
196 assert(_pc < _end, "");
197 return next_bci() + next_bytecode().get_offset_s2(Bytecodes::_ifeq);
198 }
199
200 // 4-byte branch offset from current pc
201 int get_far_dest() const {
202 return cur_bci() + bytecode().get_offset_s4(cur_bc_raw());
203 }
204
205 // For a lookup or switch table, return target destination
206 int get_int_table( int index ) const {
207 return Bytes::get_Java_u4((address)&_table_base[index]); }
208
209 int get_dest_table( int index ) const {
210 return cur_bci() + get_int_table(index); }
211
212 // --- Constant pool access ---
213 int get_constant_raw_index() const;
214 int get_constant_pool_index() const;
215 int get_field_index();
216 int get_method_index();
217
218 // If this bytecode is a new, newarray, multianewarray, instanceof,
219 // or checkcast, get the referenced klass.
220 ciKlass* get_klass(bool& will_link);
221 int get_klass_index() const;
222 bool has_Q_signature() const;
223
224 // If this bytecode is one of the ldc variants, get the referenced
225 // constant. Do not attempt to resolve it, since that would require
226 // execution of Java code. If it is not resolved, return an unloaded
227 // object (ciConstant.as_object()->is_loaded() == false).
228 ciConstant get_constant();
229 constantTag get_constant_pool_tag(int index) const;
230
231 // True if the klass-using bytecode points to an unresolved klass
232 bool is_unresolved_klass() const {
233 constantTag tag = get_constant_pool_tag(get_klass_index());
234 return tag.is_unresolved_klass();
235 }
236
237 bool is_unresolved_klass_in_error() const {
238 constantTag tag = get_constant_pool_tag(get_klass_index());
239 return tag.is_unresolved_klass_in_error();
240 }
241
242 // If this bytecode is one of get_field, get_static, put_field,
243 // or put_static, get the referenced field.
244 ciField* get_field(bool& will_link);
245
246 ciInstanceKlass* get_declared_field_holder();
247 int get_field_holder_index();
248
249 ciMethod* get_method(bool& will_link, ciSignature* *declared_signature_result);
250 bool has_appendix();
251 ciObject* get_appendix();
252 bool has_local_signature();
253 ciKlass* get_declared_method_holder();
254 int get_method_holder_index();
255 int get_method_signature_index(const constantPoolHandle& cpool);
256
257 };
258
259
260 // ciSignatureStream
261 //
262 // The class is used to iterate over the elements of a method signature.
263 class ciSignatureStream : public StackObj {
264 private:
265 ciSignature* _sig;
266 int _pos;
267 // holder is a method's holder
268 ciKlass* _holder;
269 public:
270 ciSignatureStream(ciSignature* signature, ciKlass* holder = NULL) {
271 _sig = signature;
272 _pos = 0;
273 _holder = holder;
274 }
275
276 bool at_return_type() { return _pos == _sig->count(); }
277
278 bool is_done() { return _pos > _sig->count(); }
279
280 void next() {
281 if (_pos <= _sig->count()) {
282 _pos++;
283 }
284 }
285
286 ciType* type() {
287 if (at_return_type()) {
288 return _sig->return_type();
289 } else {
290 return _sig->type_at(_pos);
291 }
292 }
293
294 bool is_null_free() {
295 if (at_return_type()) {
296 return _sig->returns_null_free_inline_type();
297 } else {
298 return _sig->is_null_free_at(_pos);
299 }
300 }
301
302 // next klass in the signature
303 ciKlass* next_klass() {
304 ciKlass* sig_k;
305 if (_holder != NULL) {
306 sig_k = _holder;
307 _holder = NULL;
308 } else {
309 while (!type()->is_klass()) {
310 next();
311 }
312 assert(!at_return_type(), "passed end of signature");
313 sig_k = type()->as_klass();
314 next();
315 }
316 return sig_k;
317 }
318 };
319
320
321 // ciExceptionHandlerStream
322 //
323 // The class is used to iterate over the exception handlers of
324 // a method.
325 class ciExceptionHandlerStream : public StackObj {
326 private:
327 // The method whose handlers we are traversing
328 ciMethod* _method;
329
330 // Our current position in the list of handlers
331 int _pos;
332 int _end;
333
334 ciInstanceKlass* _exception_klass;
335 int _bci;
336 bool _is_exact;
337
338 public:
339 ciExceptionHandlerStream(ciMethod* method) {
340 _method = method;
341
342 // Force loading of method code and handlers.
343 _method->code();
344
345 _pos = 0;
346 _end = _method->_handler_count;
347 _exception_klass = NULL;
348 _bci = -1;
349 _is_exact = false;
350 }
351
352 ciExceptionHandlerStream(ciMethod* method, int bci,
353 ciInstanceKlass* exception_klass = NULL,
354 bool is_exact = false) {
355 _method = method;
356
357 // Force loading of method code and handlers.
358 _method->code();
359
360 _pos = -1;
361 _end = _method->_handler_count + 1; // include the rethrow handler
362 _exception_klass = (exception_klass != NULL && exception_klass->is_loaded()
363 ? exception_klass
364 : NULL);
365 _bci = bci;
366 assert(_bci >= 0, "bci out of range");
367 _is_exact = is_exact;
368 next();
369 }
370
371 // These methods are currently implemented in an odd way.
372 // Count the number of handlers the iterator has ever produced
373 // or will ever produce. Do not include the final rethrow handler.
374 // That is, a trivial exception handler stream will have a count
375 // of zero and produce just the rethrow handler.
376 int count();
377
378 // Count the number of handlers this stream will produce from now on.
379 // Include the current handler, and the final rethrow handler.
380 // The remaining count will be zero iff is_done() is true,
381 int count_remaining();
382
383 bool is_done() {
384 return (_pos >= _end);
385 }
386
387 void next() {
388 _pos++;
389 if (_bci != -1) {
390 // We are not iterating over all handlers...
391 while (!is_done()) {
392 ciExceptionHandler* handler = _method->_exception_handlers[_pos];
393 if (handler->is_in_range(_bci)) {
394 if (handler->is_catch_all()) {
395 // Found final active catch block.
396 _end = _pos+1;
397 return;
398 } else if (_exception_klass == NULL || !handler->catch_klass()->is_loaded()) {
399 // We cannot do any type analysis here. Must conservatively assume
400 // catch block is reachable.
401 return;
402 } else if (_exception_klass->is_subtype_of(handler->catch_klass())) {
403 // This catch clause will definitely catch the exception.
404 // Final candidate.
405 _end = _pos+1;
406 return;
407 } else if (!_is_exact &&
408 handler->catch_klass()->is_subtype_of(_exception_klass)) {
409 // This catch block may be reachable.
410 return;
411 }
412 }
413
414 // The catch block was not pertinent. Go on.
415 _pos++;
416 }
417 } else {
418 // This is an iteration over all handlers.
419 return;
420 }
421 }
422
423 ciExceptionHandler* handler() {
424 return _method->_exception_handlers[_pos];
425 }
426 };
427
428
429
430 // Implementation for declarations in bytecode.hpp
431 Bytecode::Bytecode(const ciBytecodeStream* stream, address bcp): _bcp(bcp != NULL ? bcp : stream->cur_bcp()), _code(Bytecodes::code_at(NULL, addr_at(0))) {}
432 Bytecode_lookupswitch::Bytecode_lookupswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); }
433 Bytecode_tableswitch::Bytecode_tableswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); }
434
435 #endif // SHARE_CI_CISTREAMS_HPP