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
223 // If this bytecode is one of the ldc variants, get the referenced
224 // constant. Do not attempt to resolve it, since that would require
225 // execution of Java code. If it is not resolved, return an unloaded
226 // object (ciConstant.as_object()->is_loaded() == false).
227 ciConstant get_constant();
228 constantTag get_constant_pool_tag(int index) const;
229
230 // True if the klass-using bytecode points to an unresolved klass
231 bool is_unresolved_klass() const {
232 constantTag tag = get_constant_pool_tag(get_klass_index());
233 return tag.is_unresolved_klass();
234 }
235
236 bool is_unresolved_klass_in_error() const {
237 constantTag tag = get_constant_pool_tag(get_klass_index());
238 return tag.is_unresolved_klass_in_error();
239 }
240
241 // If this bytecode is one of get_field, get_static, put_field,
242 // or put_static, get the referenced field.
243 ciField* get_field(bool& will_link);
244
245 ciInstanceKlass* get_declared_field_holder();
246 int get_field_holder_index();
247
248 ciMethod* get_method(bool& will_link, ciSignature* *declared_signature_result);
249 bool has_appendix();
250 ciObject* get_appendix();
251 bool has_local_signature();
252 ciKlass* get_declared_method_holder();
253 int get_method_holder_index();
254 int get_method_signature_index(const constantPoolHandle& cpool);
255
256 };
257
258
259 // ciSignatureStream
260 //
261 // The class is used to iterate over the elements of a method signature.
262 class ciSignatureStream : public StackObj {
263 private:
264 ciSignature* _sig;
265 int _pos;
266 // holder is a method's holder
267 ciKlass* _holder;
268 public:
269 ciSignatureStream(ciSignature* signature, ciKlass* holder = NULL) {
270 _sig = signature;
271 _pos = 0;
272 _holder = holder;
273 }
274
275 bool at_return_type() { return _pos == _sig->count(); }
276
277 bool is_done() { return _pos > _sig->count(); }
278
279 void next() {
280 if (_pos <= _sig->count()) {
281 _pos++;
282 }
283 }
284
285 ciType* type() {
286 if (at_return_type()) {
287 return _sig->return_type();
288 } else {
289 return _sig->type_at(_pos);
290 }
291 }
292
293 // next klass in the signature
294 ciKlass* next_klass() {
295 ciKlass* sig_k;
296 if (_holder != NULL) {
297 sig_k = _holder;
298 _holder = NULL;
299 } else {
300 while (!type()->is_klass()) {
301 next();
302 }
303 assert(!at_return_type(), "passed end of signature");
304 sig_k = type()->as_klass();
305 next();
306 }
307 return sig_k;
308 }
309 };
310
311
312 // ciExceptionHandlerStream
313 //
314 // The class is used to iterate over the exception handlers of
315 // a method.
316 class ciExceptionHandlerStream : public StackObj {
317 private:
318 // The method whose handlers we are traversing
319 ciMethod* _method;
320
321 // Our current position in the list of handlers
322 int _pos;
323 int _end;
324
325 ciInstanceKlass* _exception_klass;
326 int _bci;
327 bool _is_exact;
328
329 public:
330 ciExceptionHandlerStream(ciMethod* method) {
331 _method = method;
332
333 // Force loading of method code and handlers.
334 _method->code();
335
336 _pos = 0;
337 _end = _method->_handler_count;
338 _exception_klass = NULL;
339 _bci = -1;
340 _is_exact = false;
341 }
342
343 ciExceptionHandlerStream(ciMethod* method, int bci,
344 ciInstanceKlass* exception_klass = NULL,
345 bool is_exact = false) {
346 _method = method;
347
348 // Force loading of method code and handlers.
349 _method->code();
350
351 _pos = -1;
352 _end = _method->_handler_count + 1; // include the rethrow handler
353 _exception_klass = (exception_klass != NULL && exception_klass->is_loaded()
354 ? exception_klass
355 : NULL);
356 _bci = bci;
357 assert(_bci >= 0, "bci out of range");
358 _is_exact = is_exact;
359 next();
360 }
361
362 // These methods are currently implemented in an odd way.
363 // Count the number of handlers the iterator has ever produced
364 // or will ever produce. Do not include the final rethrow handler.
365 // That is, a trivial exception handler stream will have a count
366 // of zero and produce just the rethrow handler.
367 int count();
368
369 // Count the number of handlers this stream will produce from now on.
370 // Include the current handler, and the final rethrow handler.
371 // The remaining count will be zero iff is_done() is true,
372 int count_remaining();
373
374 bool is_done() {
375 return (_pos >= _end);
376 }
377
378 void next() {
379 _pos++;
380 if (_bci != -1) {
381 // We are not iterating over all handlers...
382 while (!is_done()) {
383 ciExceptionHandler* handler = _method->_exception_handlers[_pos];
384 if (handler->is_in_range(_bci)) {
385 if (handler->is_catch_all()) {
386 // Found final active catch block.
387 _end = _pos+1;
388 return;
389 } else if (_exception_klass == NULL || !handler->catch_klass()->is_loaded()) {
390 // We cannot do any type analysis here. Must conservatively assume
391 // catch block is reachable.
392 return;
393 } else if (_exception_klass->is_subtype_of(handler->catch_klass())) {
394 // This catch clause will definitely catch the exception.
395 // Final candidate.
396 _end = _pos+1;
397 return;
398 } else if (!_is_exact &&
399 handler->catch_klass()->is_subtype_of(_exception_klass)) {
400 // This catch block may be reachable.
401 return;
402 }
403 }
404
405 // The catch block was not pertinent. Go on.
406 _pos++;
407 }
408 } else {
409 // This is an iteration over all handlers.
410 return;
411 }
412 }
413
414 ciExceptionHandler* handler() {
415 return _method->_exception_handlers[_pos];
416 }
417 };
418
419
420
421 // Implementation for declarations in bytecode.hpp
422 Bytecode::Bytecode(const ciBytecodeStream* stream, address bcp): _bcp(bcp != NULL ? bcp : stream->cur_bcp()), _code(Bytecodes::code_at(NULL, addr_at(0))) {}
423 Bytecode_lookupswitch::Bytecode_lookupswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); }
424 Bytecode_tableswitch::Bytecode_tableswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); }
425
426 #endif // SHARE_CI_CISTREAMS_HPP