1 /*
2 * Copyright (c) 1999, 2019, 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 bool has_optional_appendix() { return Bytecodes::has_optional_appendix(cur_bc_raw()); }
147
148 int get_index_u1() const {
149 return bytecode().get_index_u1(cur_bc_raw());
150 }
151
152 // Get a byte index following this bytecode.
153 // If prefixed with a wide bytecode, get a wide index.
154 int get_index() const {
155 assert(!has_cache_index(), "else use cpcache variant");
156 return (_pc == _was_wide) // was widened?
157 ? get_index_u2(true) // yes, return wide index
158 : get_index_u1(); // no, return narrow index
159 }
160
161 // Get 2-byte index (byte swapping depending on which bytecode)
162 int get_index_u2(bool is_wide = false) const {
163 return bytecode().get_index_u2(cur_bc_raw(), is_wide);
164 }
165
166 // Get 2-byte index in native byte order. (Rewriter::rewrite makes these.)
167 int get_index_u2_cpcache() const {
168 return bytecode().get_index_u2_cpcache(cur_bc_raw());
169 }
170
171 // Get 4-byte index, for invokedynamic.
172 int get_index_u4() const {
173 return bytecode().get_index_u4(cur_bc_raw());
174 }
175
176 bool has_index_u4() const {
177 return bytecode().has_index_u4(cur_bc_raw());
178 }
179
180 // Get dimensions byte (multinewarray)
181 int get_dimensions() const { return *(unsigned char*)(_pc-1); }
182
183 // Sign-extended index byte/short, no widening
184 int get_constant_u1() const { return bytecode().get_constant_u1(instruction_size()-1, cur_bc_raw()); }
185 int get_constant_u2(bool is_wide = false) const { return bytecode().get_constant_u2(instruction_size()-2, cur_bc_raw(), is_wide); }
186
187 // Get a byte signed constant for "iinc". Invalid for other bytecodes.
188 // If prefixed with a wide bytecode, get a wide constant
189 int get_iinc_con() const {return (_pc==_was_wide) ? (jshort) get_constant_u2(true) : (jbyte) get_constant_u1();}
190
191 // 2-byte branch offset from current pc
192 int get_dest() const {
193 return cur_bci() + bytecode().get_offset_s2(cur_bc_raw());
194 }
195
196 // 2-byte branch offset from next pc
197 int next_get_dest() const {
198 assert(_pc < _end, "");
199 return next_bci() + next_bytecode().get_offset_s2(Bytecodes::_ifeq);
200 }
201
202 // 4-byte branch offset from current pc
203 int get_far_dest() const {
204 return cur_bci() + bytecode().get_offset_s4(cur_bc_raw());
205 }
206
207 // For a lookup or switch table, return target destination
208 int get_int_table( int index ) const {
209 return Bytes::get_Java_u4((address)&_table_base[index]); }
210
211 int get_dest_table( int index ) const {
212 return cur_bci() + get_int_table(index); }
213
214 // --- Constant pool access ---
215 int get_constant_raw_index() const;
216 int get_constant_pool_index() const;
217 int get_field_index();
218 int get_method_index();
219
220 // If this bytecode is a new, newarray, multianewarray, instanceof,
221 // or checkcast, get the referenced klass.
222 ciKlass* get_klass(bool& will_link);
223 int get_klass_index() const;
224 bool is_klass_never_null() const;
225
226 // If this bytecode is one of the ldc variants, get the referenced
227 // constant. Do not attempt to resolve it, since that would require
228 // execution of Java code. If it is not resolved, return an unloaded
229 // object (ciConstant.as_object()->is_loaded() == false).
230 ciConstant get_constant();
231 constantTag get_constant_pool_tag(int index) const;
232
233 // True if the klass-using bytecode points to an unresolved klass
234 bool is_unresolved_klass() const {
235 constantTag tag = get_constant_pool_tag(get_klass_index());
236 return tag.is_unresolved_klass();
237 }
238
239 // If this bytecode is one of get_field, get_static, put_field,
240 // or put_static, get the referenced field.
241 ciField* get_field(bool& will_link);
242
243 ciInstanceKlass* get_declared_field_holder();
244 int get_field_holder_index();
245
246 ciMethod* get_method(bool& will_link, ciSignature* *declared_signature_result);
247 bool has_appendix();
248 ciObject* get_appendix();
249 bool has_local_signature();
250 ciKlass* get_declared_method_holder();
251 int get_method_holder_index();
252 int get_method_signature_index(const constantPoolHandle& cpool);
253
254 };
255
256
257 // ciSignatureStream
258 //
259 // The class is used to iterate over the elements of a method signature.
260 class ciSignatureStream : public StackObj {
261 private:
262 ciSignature* _sig;
263 int _pos;
264 // holder is a method's holder
265 ciKlass* _holder;
266 public:
267 ciSignatureStream(ciSignature* signature, ciKlass* holder = NULL) {
268 _sig = signature;
269 _pos = 0;
270 _holder = holder;
271 }
272
273 bool at_return_type() { return _pos == _sig->count(); }
274
275 bool is_done() { return _pos > _sig->count(); }
276
277 void next() {
278 if (_pos <= _sig->count()) {
279 _pos++;
280 }
281 }
282
283 ciType* type() {
284 if (at_return_type()) {
285 return _sig->return_type();
286 } else {
287 return _sig->type_at(_pos);
288 }
289 }
290
291 bool is_never_null() {
292 if (at_return_type()) {
293 return _sig->returns_never_null();
294 } else {
295 return _sig->is_never_null_at(_pos);
296 }
297 }
298
299 // next klass in the signature
300 ciKlass* next_klass() {
301 ciKlass* sig_k;
302 if (_holder != NULL) {
303 sig_k = _holder;
304 _holder = NULL;
305 } else {
306 while (!type()->is_klass()) {
307 next();
308 }
309 assert(!at_return_type(), "passed end of signature");
310 sig_k = type()->as_klass();
311 next();
312 }
313 return sig_k;
314 }
315 };
316
317
318 // ciExceptionHandlerStream
319 //
320 // The class is used to iterate over the exception handlers of
321 // a method.
322 class ciExceptionHandlerStream : public StackObj {
323 private:
324 // The method whose handlers we are traversing
325 ciMethod* _method;
326
327 // Our current position in the list of handlers
328 int _pos;
329 int _end;
330
331 ciInstanceKlass* _exception_klass;
332 int _bci;
333 bool _is_exact;
334
335 public:
336 ciExceptionHandlerStream(ciMethod* method) {
337 _method = method;
338
339 // Force loading of method code and handlers.
340 _method->code();
341
342 _pos = 0;
343 _end = _method->_handler_count;
344 _exception_klass = NULL;
345 _bci = -1;
346 _is_exact = false;
347 }
348
349 ciExceptionHandlerStream(ciMethod* method, int bci,
350 ciInstanceKlass* exception_klass = NULL,
351 bool is_exact = false) {
352 _method = method;
353
354 // Force loading of method code and handlers.
355 _method->code();
356
357 _pos = -1;
358 _end = _method->_handler_count + 1; // include the rethrow handler
359 _exception_klass = (exception_klass != NULL && exception_klass->is_loaded()
360 ? exception_klass
361 : NULL);
362 _bci = bci;
363 assert(_bci >= 0, "bci out of range");
364 _is_exact = is_exact;
365 next();
366 }
367
368 // These methods are currently implemented in an odd way.
369 // Count the number of handlers the iterator has ever produced
370 // or will ever produce. Do not include the final rethrow handler.
371 // That is, a trivial exception handler stream will have a count
372 // of zero and produce just the rethrow handler.
373 int count();
374
375 // Count the number of handlers this stream will produce from now on.
376 // Include the current handler, and the final rethrow handler.
377 // The remaining count will be zero iff is_done() is true,
378 int count_remaining();
379
380 bool is_done() {
381 return (_pos >= _end);
382 }
383
384 void next() {
385 _pos++;
386 if (_bci != -1) {
387 // We are not iterating over all handlers...
388 while (!is_done()) {
389 ciExceptionHandler* handler = _method->_exception_handlers[_pos];
390 if (handler->is_in_range(_bci)) {
391 if (handler->is_catch_all()) {
392 // Found final active catch block.
393 _end = _pos+1;
394 return;
395 } else if (_exception_klass == NULL || !handler->catch_klass()->is_loaded()) {
396 // We cannot do any type analysis here. Must conservatively assume
397 // catch block is reachable.
398 return;
399 } else if (_exception_klass->is_subtype_of(handler->catch_klass())) {
400 // This catch clause will definitely catch the exception.
401 // Final candidate.
402 _end = _pos+1;
403 return;
404 } else if (!_is_exact &&
405 handler->catch_klass()->is_subtype_of(_exception_klass)) {
406 // This catch block may be reachable.
407 return;
408 }
409 }
410
411 // The catch block was not pertinent. Go on.
412 _pos++;
413 }
414 } else {
415 // This is an iteration over all handlers.
416 return;
417 }
418 }
419
420 ciExceptionHandler* handler() {
421 return _method->_exception_handlers[_pos];
422 }
423 };
424
425
426
427 // Implementation for declarations in bytecode.hpp
428 Bytecode::Bytecode(const ciBytecodeStream* stream, address bcp): _bcp(bcp != NULL ? bcp : stream->cur_bcp()), _code(Bytecodes::code_at(NULL, addr_at(0))) {}
429 Bytecode_lookupswitch::Bytecode_lookupswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); }
430 Bytecode_tableswitch::Bytecode_tableswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); }
431
432 #endif // SHARE_CI_CISTREAMS_HPP