1 /*
2 * Copyright (c) 1999, 2018, 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 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 void assert_wide(bool require_wide) const {
74 if (require_wide)
75 { assert(is_wide(), "must be a wide instruction"); }
76 else { assert(!is_wide(), "must not be a wide instruction"); }
77 }
78
79 Bytecode bytecode() const { return Bytecode(this, _bc_start); }
80 Bytecode next_bytecode() const { return Bytecode(this, _pc); }
81
82 public:
83 // End-Of-Bytecodes
84 static Bytecodes::Code EOBC() {
85 return Bytecodes::_illegal;
86 }
87
88 ciBytecodeStream(ciMethod* m) {
89 reset_to_method(m);
90 }
91
92 ciBytecodeStream() {
93 reset_to_method(NULL);
94 }
95
96 ciMethod* method() const { return _method; }
97
98 void reset_to_method(ciMethod* m) {
99 _method = m;
100 if (m == NULL) {
101 _holder = NULL;
102 reset(NULL, 0);
103 } else {
104 _holder = m->holder();
105 reset(m->code(), m->code_size());
106 }
107 }
108
109 void reset_to_bci( int bci );
110
111 // Force the iterator to report a certain bci.
112 void force_bci(int bci);
113
114 void set_max_bci( int max ) {
115 _end = _start + max;
116 }
117
118 address cur_bcp() const { return _bc_start; } // Returns bcp to current instruction
119 int next_bci() const { return _pc - _start; }
120 int cur_bci() const { return _bc_start - _start; }
121 int instruction_size() const { return _pc - _bc_start; }
122
123 Bytecodes::Code cur_bc() const{ return check_java(_bc); }
124 Bytecodes::Code cur_bc_raw() const { return check_defined(_raw_bc); }
125 Bytecodes::Code next_bc() { return Bytecodes::java_code((Bytecodes::Code)* _pc); }
126
127 // Return current ByteCode and increment PC to next bytecode, skipping all
128 // intermediate constants. Returns EOBC at end.
129 // Expected usage:
130 // ciBytecodeStream iter(m);
131 // while (iter.next() != ciBytecodeStream::EOBC()) { ... }
132 Bytecodes::Code next() {
133 _bc_start = _pc; // Capture start of bc
134 if( _pc >= _end ) return EOBC(); // End-Of-Bytecodes
135
136 // Fetch Java bytecode
137 // All rewritten bytecodes maintain the size of original bytecode.
138 _bc = Bytecodes::java_code(_raw_bc = (Bytecodes::Code)*_pc);
139 int csize = Bytecodes::length_for(_bc); // Expected size
140 _pc += csize; // Bump PC past bytecode
141 if (csize == 0) {
142 _bc = next_wide_or_table(_bc);
143 }
144 return check_java(_bc);
145 }
146
147 bool is_wide() const { return ( _pc == _was_wide ); }
148
149 // Does this instruction contain an index which refes into the CP cache?
150 bool has_cache_index() const { return Bytecodes::uses_cp_cache(cur_bc_raw()); }
151
152 bool has_optional_appendix() { return Bytecodes::has_optional_appendix(cur_bc_raw()); }
153
154 int get_index_u1() const {
155 return bytecode().get_index_u1(cur_bc_raw());
156 }
157
158 int get_index_u1_cpcache() const {
159 return bytecode().get_index_u1_cpcache(cur_bc_raw());
160 }
161
162 // Get a byte index following this bytecode.
163 // If prefixed with a wide bytecode, get a wide index.
164 int get_index() const {
165 assert(!has_cache_index(), "else use cpcache variant");
166 return (_pc == _was_wide) // was widened?
167 ? get_index_u2(true) // yes, return wide index
168 : get_index_u1(); // no, return narrow index
169 }
170
171 // Get 2-byte index (byte swapping depending on which bytecode)
172 int get_index_u2(bool is_wide = false) const {
173 return bytecode().get_index_u2(cur_bc_raw(), is_wide);
174 }
175
176 // Get 2-byte index in native byte order. (Rewriter::rewrite makes these.)
177 int get_index_u2_cpcache() const {
178 return bytecode().get_index_u2_cpcache(cur_bc_raw());
179 }
180
181 // Get 4-byte index, for invokedynamic.
182 int get_index_u4() const {
183 return bytecode().get_index_u4(cur_bc_raw());
184 }
185
186 bool has_index_u4() const {
187 return bytecode().has_index_u4(cur_bc_raw());
188 }
189
190 // Get dimensions byte (multinewarray)
191 int get_dimensions() const { return *(unsigned char*)(_pc-1); }
192
193 // Sign-extended index byte/short, no widening
194 int get_constant_u1() const { return bytecode().get_constant_u1(instruction_size()-1, cur_bc_raw()); }
195 int get_constant_u2(bool is_wide = false) const { return bytecode().get_constant_u2(instruction_size()-2, cur_bc_raw(), is_wide); }
196
197 // Get a byte signed constant for "iinc". Invalid for other bytecodes.
198 // If prefixed with a wide bytecode, get a wide constant
199 int get_iinc_con() const {return (_pc==_was_wide) ? (jshort) get_constant_u2(true) : (jbyte) get_constant_u1();}
200
201 // 2-byte branch offset from current pc
202 int get_dest() const {
203 return cur_bci() + bytecode().get_offset_s2(cur_bc_raw());
204 }
205
206 // 2-byte branch offset from next pc
207 int next_get_dest() const {
208 assert(_pc < _end, "");
209 return next_bci() + next_bytecode().get_offset_s2(Bytecodes::_ifeq);
210 }
211
212 // 4-byte branch offset from current pc
213 int get_far_dest() const {
214 return cur_bci() + bytecode().get_offset_s4(cur_bc_raw());
215 }
216
217 // For a lookup or switch table, return target destination
218 int get_int_table( int index ) const {
219 return Bytes::get_Java_u4((address)&_table_base[index]); }
220
221 // For tableswitch - get length of offset part
222 int get_tableswitch_length() { return get_int_table(2)-get_int_table(1)+1; }
223
224 int get_dest_table( int index ) const {
225 return cur_bci() + get_int_table(index); }
226
227 // --- Constant pool access ---
228 int get_constant_raw_index() const;
229 int get_constant_pool_index() const;
230 int get_constant_cache_index() const;
231 int get_field_index();
232 int get_method_index();
233
234 // If this bytecode is a new, newarray, multianewarray, instanceof,
235 // or checkcast, get the referenced klass.
236 ciKlass* get_klass(bool& will_link);
237 int get_klass_index() const;
238 bool is_klass_never_null() const;
239
240 // If this bytecode is one of the ldc variants, get the referenced
241 // constant. Do not attempt to resolve it, since that would require
242 // execution of Java code. If it is not resolved, return an unloaded
243 // object (ciConstant.as_object()->is_loaded() == false).
244 ciConstant get_constant();
245 constantTag get_constant_pool_tag(int index) const;
246
247 // True if the klass-using bytecode points to an unresolved klass
248 bool is_unresolved_klass() const {
249 constantTag tag = get_constant_pool_tag(get_klass_index());
250 return tag.is_unresolved_klass();
251 }
252
253 // If this bytecode is one of get_field, get_static, put_field,
254 // or put_static, get the referenced field.
255 ciField* get_field(bool& will_link);
256
257 ciInstanceKlass* get_declared_field_holder();
258 int get_field_holder_index();
259 int get_field_signature_index();
260
261 ciMethod* get_method(bool& will_link, ciSignature* *declared_signature_result);
262 bool has_appendix();
263 ciObject* get_appendix();
264 bool has_method_type();
265 ciMethodType* get_method_type();
266 ciKlass* get_declared_method_holder();
267 int get_method_holder_index();
268 int get_method_signature_index(const constantPoolHandle& cpool);
269
270 // Get the resolved references arrays from the constant pool
271 ciObjArray* get_resolved_references();
272 };
273
274
275 // ciSignatureStream
276 //
277 // The class is used to iterate over the elements of a method signature.
278 class ciSignatureStream : public StackObj {
279 private:
280 ciSignature* _sig;
281 int _pos;
282 // holder is a method's holder
283 ciKlass* _holder;
284 public:
285 ciSignatureStream(ciSignature* signature, ciKlass* holder = NULL) {
286 _sig = signature;
287 _pos = 0;
288 _holder = holder;
289 }
290
291 bool at_return_type() { return _pos == _sig->count(); }
292
293 bool is_done() { return _pos > _sig->count(); }
294
295 void next() {
296 if (_pos <= _sig->count()) {
297 _pos++;
298 }
299 }
300
301 ciType* type() {
302 if (at_return_type()) {
303 return _sig->return_type();
304 } else {
305 return _sig->type_at(_pos);
306 }
307 }
308
309 bool is_never_null() {
310 if (at_return_type()) {
311 return _sig->returns_never_null();
312 } else {
313 return _sig->is_never_null_at(_pos);
314 }
315 }
316
317 // next klass in the signature
318 ciKlass* next_klass() {
319 ciKlass* sig_k;
320 if (_holder != NULL) {
321 sig_k = _holder;
322 _holder = NULL;
323 } else {
324 while (!type()->is_klass()) {
325 next();
326 }
327 assert(!at_return_type(), "passed end of signature");
328 sig_k = type()->as_klass();
329 next();
330 }
331 return sig_k;
332 }
333 };
334
335
336 // ciExceptionHandlerStream
337 //
338 // The class is used to iterate over the exception handlers of
339 // a method.
340 class ciExceptionHandlerStream : public StackObj {
341 private:
342 // The method whose handlers we are traversing
343 ciMethod* _method;
344
345 // Our current position in the list of handlers
346 int _pos;
347 int _end;
348
349 ciInstanceKlass* _exception_klass;
350 int _bci;
351 bool _is_exact;
352
353 public:
354 ciExceptionHandlerStream(ciMethod* method) {
355 _method = method;
356
357 // Force loading of method code and handlers.
358 _method->code();
359
360 _pos = 0;
361 _end = _method->_handler_count;
362 _exception_klass = NULL;
363 _bci = -1;
364 _is_exact = false;
365 }
366
367 ciExceptionHandlerStream(ciMethod* method, int bci,
368 ciInstanceKlass* exception_klass = NULL,
369 bool is_exact = false) {
370 _method = method;
371
372 // Force loading of method code and handlers.
373 _method->code();
374
375 _pos = -1;
376 _end = _method->_handler_count + 1; // include the rethrow handler
377 _exception_klass = (exception_klass != NULL && exception_klass->is_loaded()
378 ? exception_klass
379 : NULL);
380 _bci = bci;
381 assert(_bci >= 0, "bci out of range");
382 _is_exact = is_exact;
383 next();
384 }
385
386 // These methods are currently implemented in an odd way.
387 // Count the number of handlers the iterator has ever produced
388 // or will ever produce. Do not include the final rethrow handler.
389 // That is, a trivial exception handler stream will have a count
390 // of zero and produce just the rethrow handler.
391 int count();
392
393 // Count the number of handlers this stream will produce from now on.
394 // Include the current handler, and the final rethrow handler.
395 // The remaining count will be zero iff is_done() is true,
396 int count_remaining();
397
398 bool is_done() {
399 return (_pos >= _end);
400 }
401
402 void next() {
403 _pos++;
404 if (_bci != -1) {
405 // We are not iterating over all handlers...
406 while (!is_done()) {
407 ciExceptionHandler* handler = _method->_exception_handlers[_pos];
408 if (handler->is_in_range(_bci)) {
409 if (handler->is_catch_all()) {
410 // Found final active catch block.
411 _end = _pos+1;
412 return;
413 } else if (_exception_klass == NULL || !handler->catch_klass()->is_loaded()) {
414 // We cannot do any type analysis here. Must conservatively assume
415 // catch block is reachable.
416 return;
417 } else if (_exception_klass->is_subtype_of(handler->catch_klass())) {
418 // This catch clause will definitely catch the exception.
419 // Final candidate.
420 _end = _pos+1;
421 return;
422 } else if (!_is_exact &&
423 handler->catch_klass()->is_subtype_of(_exception_klass)) {
424 // This catch block may be reachable.
425 return;
426 }
427 }
428
429 // The catch block was not pertinent. Go on.
430 _pos++;
431 }
432 } else {
433 // This is an iteration over all handlers.
434 return;
435 }
436 }
437
438 ciExceptionHandler* handler() {
439 return _method->_exception_handlers[_pos];
440 }
441 };
442
443
444
445 // Implementation for declarations in bytecode.hpp
446 Bytecode::Bytecode(const ciBytecodeStream* stream, address bcp): _bcp(bcp != NULL ? bcp : stream->cur_bcp()), _code(Bytecodes::code_at(NULL, addr_at(0))) {}
447 Bytecode_lookupswitch::Bytecode_lookupswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); }
448 Bytecode_tableswitch::Bytecode_tableswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); }
449
450 #endif // SHARE_VM_CI_CISTREAMS_HPP