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 #include "precompiled.hpp"
 26 #include "c1/c1_IR.hpp"
 27 #include "c1/c1_InstructionPrinter.hpp"
 28 #include "c1/c1_ValueStack.hpp"
 29 
 30 
 31 // Implementation of ValueStack
 32 
 33 ValueStack::ValueStack(IRScope* scope, ValueStack* caller_state)
 34 : _scope(scope)
 35 , _caller_state(caller_state)
 36 , _bci(-99)
 37 , _kind(Parsing)
 38 , _should_reexecute(false)
 39 , _locals(scope->method()->max_locals(), scope->method()->max_locals(), NULL)
 40 , _stack(scope->method()->max_stack())
 41 , _locks(NULL)
 42 {
 43   verify();
 44 }
 45 
 46 ValueStack::ValueStack(ValueStack* copy_from, Kind kind, int bci, bool reexecute)
 47   : _scope(copy_from->scope())
 48   , _caller_state(copy_from->caller_state())
 49   , _bci(bci)
 50   , _kind(kind)
 51   , _should_reexecute(reexecute)
 52   , _locals(copy_from->locals_size_for_copy(kind))
 53   , _stack(copy_from->stack_size_for_copy(kind))
 54   , _locks(copy_from->locks_size() == 0 ? NULL : new Values(copy_from->locks_size()))
 55 {
 56   assert(kind != EmptyExceptionState || !Compilation::current()->env()->should_retain_local_variables(), "need locals");
 57   if (kind != EmptyExceptionState) {
 58     _locals.appendAll(&copy_from->_locals);
 59   }
 60 
 61   if (kind != ExceptionState && kind != EmptyExceptionState) {
 62     _stack.appendAll(&copy_from->_stack);
 63   }
 64 
 65   if (copy_from->locks_size() > 0) {
 66     _locks->appendAll(copy_from->_locks);
 67   }
 68 
 69   verify();
 70 }
 71 
 72 int ValueStack::locals_size_for_copy(Kind kind) const {
 73   if (kind != EmptyExceptionState) {
 74     return locals_size();
 75   }
 76   return 0;
 77 }
 78 
 79 int ValueStack::stack_size_for_copy(Kind kind) const {
 80   if (kind != ExceptionState && kind != EmptyExceptionState) {
 81     if (kind == Parsing) {
 82       // stack will be modified, so reserve enough space to avoid resizing
 83       return scope()->method()->max_stack();
 84     } else {
 85       // stack will not be modified, so do not waste space
 86       return stack_size();
 87     }
 88   }
 89   return 0;
 90 }
 91 
 92 bool ValueStack::is_same(ValueStack* s) {
 93   if (scope() != s->scope()) return false;
 94   if (caller_state() != s->caller_state()) return false;
 95 
 96   if (locals_size() != s->locals_size()) return false;
 97   if (stack_size() != s->stack_size()) return false;
 98   if (locks_size() != s->locks_size()) return false;
 99 
100   // compare each stack element with the corresponding stack element of s
101   int index;
102   Value value;
103   for_each_stack_value(this, index, value) {
104     if (value->type()->tag() != s->stack_at(index)->type()->tag()) return false;
105   }
106   for (int i = 0; i < locks_size(); i++) {
107     value = lock_at(i);
108     if (value != NULL && value != s->lock_at(i)) {
109       return false;
110     }
111   }
112   return true;
113 }
114 
115 void ValueStack::clear_locals() {
116   for (int i = _locals.length() - 1; i >= 0; i--) {
117     _locals.at_put(i, NULL);
118   }
119 }
120 
121 
122 void ValueStack::pin_stack_for_linear_scan() {
123   for_each_state_value(this, v,
124     if (v->as_Constant() == NULL && v->as_Local() == NULL) {
125       v->pin(Instruction::PinStackForStateSplit);
126     }
127   );
128 }
129 
130 
131 // apply function to all values of a list; factored out from values_do(f)
132 void ValueStack::apply(const Values& list, ValueVisitor* f) {
133   for (int i = 0; i < list.length(); i++) {
134     Value* va = list.adr_at(i);
135     Value v0 = *va;
136     if (v0 != NULL && !v0->type()->is_illegal()) {
137       f->visit(va);
138 #ifdef ASSERT
139       Value v1 = *va;
140       assert(v1->type()->is_illegal() || v0->type()->tag() == v1->type()->tag(), "types must match");
141       assert(!v1->type()->is_double_word() || list.at(i + 1) == NULL, "hi-word of doubleword value must be NULL");
142 #endif
143       if (v0->type()->is_double_word()) i++;
144     }
145   }
146 }
147 
148 
149 void ValueStack::values_do(ValueVisitor* f) {
150   ValueStack* state = this;
151   for_each_state(state) {
152     apply(state->_locals, f);
153     apply(state->_stack, f);
154     if (state->_locks != NULL) {
155       apply(*state->_locks, f);
156     }
157   }
158 }
159 
160 
161 Values* ValueStack::pop_arguments(int argument_size) {
162   assert(stack_size() >= argument_size, "stack too small or too many arguments");
163   int base = stack_size() - argument_size;
164   Values* args = new Values(argument_size);
165   for (int i = base; i < stack_size();) args->push(stack_at_inc(i));
166   truncate_stack(base);
167   return args;
168 }
169 
170 
171 int ValueStack::total_locks_size() const {
172   int num_locks = 0;
173   const ValueStack* state = this;
174   for_each_state(state) {
175     num_locks += state->locks_size();
176   }
177   return num_locks;
178 }
179 
180 int ValueStack::lock(Value obj) {
181   if (_locks == NULL) {
182     _locks = new Values();
183   }
184   _locks->push(obj);
185   int num_locks = total_locks_size();
186   scope()->set_min_number_of_locks(num_locks);
187   return num_locks - 1;
188 }
189 
190 
191 int ValueStack::unlock() {
192   assert(locks_size() > 0, "sanity");
193   _locks->pop();
194   return total_locks_size();
195 }
196 
197 void ValueStack::setup_phi_for_stack(BlockBegin* b, int index) {
198   assert(stack_at(index)->as_Phi() == NULL || stack_at(index)->as_Phi()->block() != b, "phi function already created");
199 
200   ValueType* t = stack_at(index)->type();
201   Value phi = new Phi(t, b, -index - 1);
202   _stack.at_put(index, phi);
203 
204   assert(!t->is_double_word() || _stack.at(index + 1) == NULL, "hi-word of doubleword value must be NULL");
205 }
206 
207 void ValueStack::setup_phi_for_local(BlockBegin* b, int index) {
208   assert(local_at(index)->as_Phi() == NULL || local_at(index)->as_Phi()->block() != b, "phi function already created");
209 
210   ValueType* t = local_at(index)->type();
211   Value phi = new Phi(t, b, index);
212   store_local(index, phi);
213 }
214 
215 #ifndef PRODUCT
216 
217 void ValueStack::print() {
218   scope()->method()->print_name();
219   tty->cr();
220   if (stack_is_empty()) {
221     tty->print_cr("empty stack");
222   } else {
223     InstructionPrinter ip;
224     for (int i = 0; i < stack_size();) {
225       Value t = stack_at_inc(i);
226       tty->print("%2d  ", i);
227       tty->print("%c%d ", t->type()->tchar(), t->id());
228       ip.print_instr(t);
229       tty->cr();
230     }
231   }
232   if (!no_active_locks()) {
233     InstructionPrinter ip;
234     for (int i = 0; i < locks_size(); i++) {
235       Value t = lock_at(i);
236       tty->print("lock %2d  ", i);
237       if (t == NULL) {
238         tty->print("this");
239       } else {
240         tty->print("%c%d ", t->type()->tchar(), t->id());
241         ip.print_instr(t);
242       }
243       tty->cr();
244     }
245   }
246   if (locals_size() > 0) {
247     InstructionPrinter ip;
248     for (int i = 0; i < locals_size();) {
249       Value l = _locals.at(i);
250       tty->print("local %d ", i);
251       if (l == NULL) {
252         tty->print("null");
253         i ++;
254       } else {
255         tty->print("%c%d ", l->type()->tchar(), l->id());
256         ip.print_instr(l);
257         if (l->type()->is_illegal() || l->type()->is_single_word()) i ++; else i += 2;
258       }
259       tty->cr();
260     }
261   }
262 
263   if (caller_state() != NULL) {
264     caller_state()->print();
265   }
266 }
267 
268 
269 void ValueStack::verify() {
270   assert(scope() != NULL, "scope must exist");
271   if (caller_state() != NULL) {
272     assert(caller_state()->scope() == scope()->caller(), "invalid caller scope");
273     caller_state()->verify();
274   }
275 
276   if (kind() == Parsing) {
277     assert(bci() == -99, "bci not defined during parsing");
278   } else {
279     assert(bci() >= -1, "bci out of range");
280     assert(bci() < scope()->method()->code_size(), "bci out of range");
281     assert(bci() == SynchronizationEntryBCI || Bytecodes::is_defined(scope()->method()->java_code_at_bci(bci())), "make sure bci points at a real bytecode");
282     assert(scope()->method()->liveness_at_bci(bci()).is_valid(), "liveness at bci must be valid");
283   }
284 
285   int i;
286   for (i = 0; i < stack_size(); i++) {
287     Value v = _stack.at(i);
288     if (v == NULL) {
289       assert(_stack.at(i - 1)->type()->is_double_word(), "only hi-words are NULL on stack");
290     } else if (v->type()->is_double_word()) {
291       assert(_stack.at(i + 1) == NULL, "hi-word must be NULL");
292     }
293   }
294 
295   for (i = 0; i < locals_size(); i++) {
296     Value v = _locals.at(i);
297     if (v != NULL && v->type()->is_double_word()) {
298       assert(_locals.at(i + 1) == NULL, "hi-word must be NULL");
299     }
300   }
301 
302   for_each_state_value(this, v,
303     assert(v != NULL, "just test if state-iteration succeeds");
304   );
305 }
306 #endif // PRODUCT