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