1 /*
   2  * Copyright (c) 1999, 2010, 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(), 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()->jvmti_can_access_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   _locks.appendAll(&copy_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 
 176 void ValueStack::setup_phi_for_stack(BlockBegin* b, int index) {
 177   assert(stack_at(index)->as_Phi() == NULL || stack_at(index)->as_Phi()->block() != b, "phi function already created");
 178 
 179   ValueType* t = stack_at(index)->type();
 180   Value phi = new Phi(t, b, -index - 1);
 181   _stack[index] = phi;
 182 
 183   assert(!t->is_double_word() || _stack.at(index + 1) == NULL, "hi-word of doubleword value must be NULL");
 184 }
 185 
 186 void ValueStack::setup_phi_for_local(BlockBegin* b, int index) {
 187   assert(local_at(index)->as_Phi() == NULL || local_at(index)->as_Phi()->block() != b, "phi function already created");
 188 
 189   ValueType* t = local_at(index)->type();
 190   Value phi = new Phi(t, b, index);
 191   store_local(index, phi);
 192 }
 193 
 194 #ifndef PRODUCT
 195 
 196 void ValueStack::print() {
 197   scope()->method()->print_name();
 198   if (stack_is_empty()) {
 199     tty->print_cr("empty stack");
 200   } else {
 201     InstructionPrinter ip;
 202     for (int i = 0; i < stack_size();) {
 203       Value t = stack_at_inc(i);
 204       tty->print("%2d  ", i);
 205       tty->print("%c%d ", t->type()->tchar(), t->id());
 206       ip.print_instr(t);
 207       tty->cr();
 208     }
 209   }
 210   if (!no_active_locks()) {
 211     InstructionPrinter ip;
 212     for (int i = 0; i < locks_size(); i++) {
 213       Value t = lock_at(i);
 214       tty->print("lock %2d  ", i);
 215       if (t == NULL) {
 216         tty->print("this");
 217       } else {
 218         tty->print("%c%d ", t->type()->tchar(), t->id());
 219         ip.print_instr(t);
 220       }
 221       tty->cr();
 222     }
 223   }
 224   if (locals_size() > 0) {
 225     InstructionPrinter ip;
 226     for (int i = 0; i < locals_size();) {
 227       Value l = _locals[i];
 228       tty->print("local %d ", i);
 229       if (l == NULL) {
 230         tty->print("null");
 231         i ++;
 232       } else {
 233         tty->print("%c%d ", l->type()->tchar(), l->id());
 234         ip.print_instr(l);
 235         if (l->type()->is_illegal() || l->type()->is_single_word()) i ++; else i += 2;
 236       }
 237       tty->cr();
 238     }
 239   }
 240 
 241   if (caller_state() != NULL) {
 242     caller_state()->print();
 243   }
 244 }
 245 
 246 
 247 void ValueStack::verify() {
 248   assert(scope() != NULL, "scope must exist");
 249   if (caller_state() != NULL) {
 250     assert(caller_state()->scope() == scope()->caller(), "invalid caller scope");
 251     caller_state()->verify();
 252   }
 253 
 254   if (kind() == Parsing) {
 255     assert(bci() == -99, "bci not defined during parsing");
 256   } else {
 257     assert(bci() >= -1, "bci out of range");
 258     assert(bci() < scope()->method()->code_size(), "bci out of range");
 259     assert(bci() == SynchronizationEntryBCI || Bytecodes::is_defined(scope()->method()->java_code_at_bci(bci())), "make sure bci points at a real bytecode");
 260     assert(scope()->method()->liveness_at_bci(bci()).is_valid(), "liveness at bci must be valid");
 261   }
 262 
 263   int i;
 264   for (i = 0; i < stack_size(); i++) {
 265     Value v = _stack.at(i);
 266     if (v == NULL) {
 267       assert(_stack.at(i - 1)->type()->is_double_word(), "only hi-words are NULL on stack");
 268     } else if (v->type()->is_double_word()) {
 269       assert(_stack.at(i + 1) == NULL, "hi-word must be NULL");
 270     }
 271   }
 272 
 273   for (i = 0; i < locals_size(); i++) {
 274     Value v = _locals.at(i);
 275     if (v != NULL && v->type()->is_double_word()) {
 276       assert(_locals.at(i + 1) == NULL, "hi-word must be NULL");
 277     }
 278   }
 279 
 280   for_each_state_value(this, v,
 281     assert(v != NULL, "just test if state-iteration succeeds");
 282   );
 283 }
 284 #endif // PRODUCT