1 /*
2 * Copyright (c) 1999, 2016, 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 , _locals(scope->method()->max_locals(), scope->method()->max_locals(), NULL)
39 , _stack(scope->method()->max_stack())
40 , _locks()
41 {
42 verify();
43 }
44
45
46 ValueStack::ValueStack(ValueStack* copy_from, Kind kind, int bci)
47 : _scope(copy_from->scope())
48 , _caller_state(copy_from->caller_state())
49 , _bci(bci)
50 , _kind(kind)
51 , _locals()
52 , _stack()
53 , _locks(copy_from->locks_size())
54 {
55 assert(kind != EmptyExceptionState || !Compilation::current()->env()->should_retain_local_variables(), "need locals");
56 if (kind != EmptyExceptionState) {
57 // only allocate space if we need to copy the locals-array
58 _locals = Values(copy_from->locals_size());
59 _locals.appendAll(©_from->_locals);
60 }
61
62 if (kind != ExceptionState && kind != EmptyExceptionState) {
63 if (kind == Parsing) {
64 // stack will be modified, so reserve enough space to avoid resizing
65 _stack = Values(scope()->method()->max_stack());
66 } else {
67 // stack will not be modified, so do not waste space
68 _stack = Values(copy_from->stack_size());
69 }
70 _stack.appendAll(©_from->_stack);
71 }
72
73 _locks.appendAll(©_from->_locks);
74
75 verify();
76 }
77
78
79 bool ValueStack::is_same(ValueStack* s) {
80 if (scope() != s->scope()) return false;
81 if (caller_state() != s->caller_state()) return false;
82
83 if (locals_size() != s->locals_size()) return false;
84 if (stack_size() != s->stack_size()) return false;
85 if (locks_size() != s->locks_size()) return false;
86
87 // compare each stack element with the corresponding stack element of s
88 int index;
89 Value value;
90 for_each_stack_value(this, index, value) {
91 if (value->type()->tag() != s->stack_at(index)->type()->tag()) return false;
92 }
93 for_each_lock_value(this, index, value) {
94 if (value != s->lock_at(index)) return false;
95 }
96 return true;
97 }
98
99 void ValueStack::clear_locals() {
100 for (int i = _locals.length() - 1; i >= 0; i--) {
101 _locals.at_put(i, NULL);
102 }
103 }
104
105
106 void ValueStack::pin_stack_for_linear_scan() {
107 for_each_state_value(this, v,
108 if (v->as_Constant() == NULL && v->as_Local() == NULL) {
109 v->pin(Instruction::PinStackForStateSplit);
110 }
111 );
112 }
113
114
115 // apply function to all values of a list; factored out from values_do(f)
116 void ValueStack::apply(Values list, ValueVisitor* f) {
117 for (int i = 0; i < list.length(); i++) {
118 Value* va = list.adr_at(i);
119 Value v0 = *va;
120 if (v0 != NULL && !v0->type()->is_illegal()) {
121 f->visit(va);
122 #ifdef ASSERT
123 Value v1 = *va;
124 assert(v1->type()->is_illegal() || v0->type()->tag() == v1->type()->tag(), "types must match");
125 assert(!v1->type()->is_double_word() || list.at(i + 1) == NULL, "hi-word of doubleword value must be NULL");
126 #endif
127 if (v0->type()->is_double_word()) i++;
128 }
129 }
130 }
131
132
133 void ValueStack::values_do(ValueVisitor* f) {
134 ValueStack* state = this;
135 for_each_state(state) {
136 apply(state->_locals, f);
137 apply(state->_stack, f);
138 apply(state->_locks, f);
139 }
140 }
141
142
143 Values* ValueStack::pop_arguments(int argument_size) {
144 assert(stack_size() >= argument_size, "stack too small or too many arguments");
145 int base = stack_size() - argument_size;
146 Values* args = new Values(argument_size);
147 for (int i = base; i < stack_size();) args->push(stack_at_inc(i));
148 truncate_stack(base);
149 return args;
150 }
151
152
153 int ValueStack::total_locks_size() const {
154 int num_locks = 0;
155 const ValueStack* state = this;
156 for_each_state(state) {
157 num_locks += state->locks_size();
158 }
159 return num_locks;
160 }
161
162 int ValueStack::lock(Value obj) {
163 _locks.push(obj);
164 int num_locks = total_locks_size();
165 scope()->set_min_number_of_locks(num_locks);
166 return num_locks - 1;
167 }
168
169
170 int ValueStack::unlock() {
171 _locks.pop();
172 return total_locks_size();
173 }
174
175 // When we merge two object slots, we usually lose the type information.
176 // However, for aaload/aastore to work with flattened arrays, we need to preserve
177 // the type info (because the aaload/aastore bytecode themselves don't carry the
178 // type info).
179 ciType* ValueStack::merge_if_flattened_array_types(Value existing_value, Value new_value) {
180 assert(new_value != NULL, "must be");
181 assert(existing_value != new_value, "must be");
182
183 if (existing_value == NULL) {
184 if (new_value->is_flattened_array()) {
185 return new_value->exact_type();
186 } else {
187 return NULL;
188 }
189 }
190
191 if (existing_value->is_flattened_array() && new_value->is_flattened_array()) {
192 // The merged block should be able to access this value as a flattened array.
193 assert(existing_value->exact_type() == new_value->exact_type(), "must be guaranteed by verifier");
194 return existing_value->exact_type();
195 } else {
196 // The merged block cannot access value as a flattened array without first doing a type cast.
197 return NULL;
198 }
199 }
200
201 void ValueStack::setup_phi_for_stack(BlockBegin* b, int index, Value existing_value, Value new_value) {
202 assert(stack_at(index)->as_Phi() == NULL || stack_at(index)->as_Phi()->block() != b, "phi function already created");
203
204 ValueType* t = stack_at(index)->type();
205 Value phi = new Phi(t, b, -index - 1, merge_if_flattened_array_types(existing_value, new_value));
206 _stack.at_put(index, phi);
207
208 assert(!t->is_double_word() || _stack.at(index + 1) == NULL, "hi-word of doubleword value must be NULL");
209 }
210
211 void ValueStack::setup_phi_for_local(BlockBegin* b, int index, Value existing_value, Value new_value) {
212 assert(local_at(index)->as_Phi() == NULL || local_at(index)->as_Phi()->block() != b, "phi function already created");
213
214 ValueType* t = local_at(index)->type();
215 Value phi = new Phi(t, b, index, merge_if_flattened_array_types(existing_value, new_value));
216 store_local(index, phi);
217 }
218
219 #ifndef PRODUCT
220
221 void ValueStack::print() {
222 scope()->method()->print_name();
223 tty->cr();
224 if (stack_is_empty()) {
225 tty->print_cr("empty stack");
226 } else {
227 InstructionPrinter ip;
228 for (int i = 0; i < stack_size();) {
229 Value t = stack_at_inc(i);
230 tty->print("%2d ", i);
231 tty->print("%c%d ", t->type()->tchar(), t->id());
232 ip.print_instr(t);
233 tty->cr();
234 }
235 }
236 if (!no_active_locks()) {
237 InstructionPrinter ip;
238 for (int i = 0; i < locks_size(); i++) {
239 Value t = lock_at(i);
240 tty->print("lock %2d ", i);
241 if (t == NULL) {
242 tty->print("this");
243 } else {
244 tty->print("%c%d ", t->type()->tchar(), t->id());
245 ip.print_instr(t);
246 }
247 tty->cr();
248 }
249 }
250 if (locals_size() > 0) {
251 InstructionPrinter ip;
252 for (int i = 0; i < locals_size();) {
253 Value l = _locals.at(i);
254 tty->print("local %d ", i);
255 if (l == NULL) {
256 tty->print("null");
257 i ++;
258 } else {
259 tty->print("%c%d ", l->type()->tchar(), l->id());
260 ip.print_instr(l);
261 if (l->type()->is_illegal() || l->type()->is_single_word()) i ++; else i += 2;
262 }
263 tty->cr();
264 }
265 }
266
267 if (caller_state() != NULL) {
268 caller_state()->print();
269 }
270 }
271
272
273 void ValueStack::verify() {
274 assert(scope() != NULL, "scope must exist");
275 if (caller_state() != NULL) {
276 assert(caller_state()->scope() == scope()->caller(), "invalid caller scope");
277 caller_state()->verify();
278 }
279
280 if (kind() == Parsing) {
281 assert(bci() == -99, "bci not defined during parsing");
282 } else {
283 assert(bci() >= -1, "bci out of range");
284 assert(bci() < scope()->method()->code_size(), "bci out of range");
285 assert(bci() == SynchronizationEntryBCI || Bytecodes::is_defined(scope()->method()->java_code_at_bci(bci())), "make sure bci points at a real bytecode");
286 assert(scope()->method()->liveness_at_bci(bci()).is_valid(), "liveness at bci must be valid");
287 }
288
289 int i;
290 for (i = 0; i < stack_size(); i++) {
291 Value v = _stack.at(i);
292 if (v == NULL) {
293 assert(_stack.at(i - 1)->type()->is_double_word(), "only hi-words are NULL on stack");
294 } else if (v->type()->is_double_word()) {
295 assert(_stack.at(i + 1) == NULL, "hi-word must be NULL");
296 }
297 }
298
299 for (i = 0; i < locals_size(); i++) {
300 Value v = _locals.at(i);
301 if (v != NULL && v->type()->is_double_word()) {
302 assert(_locals.at(i + 1) == NULL, "hi-word must be NULL");
303 }
304 }
305
306 for_each_state_value(this, v,
307 assert(v != NULL, "just test if state-iteration succeeds");
308 );
309 }
310 #endif // PRODUCT