/*

 * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "c1/c1_IR.hpp"

#include "c1/c1_InstructionPrinter.hpp"

#include "c1/c1_ValueStack.hpp"

// Implementation of ValueStack

ValueStack::ValueStack(IRScope* scope, ValueStack* caller_state)

: _scope(scope)

, _caller_state(caller_state)

, _bci(-99)

, _kind(Parsing)

, _locals(scope->method()->max_locals(), scope->method()->max_locals(), NULL)

, _stack(scope->method()->max_stack())

, _locks(NULL)

{

  verify();

}

ValueStack::ValueStack(ValueStack* copy_from, Kind kind, int bci)

  : _scope(copy_from->scope())

  , _caller_state(copy_from->caller_state())

  , _bci(bci)

  , _kind(kind)

  , _locals(copy_from->locals_size_for_copy(kind))

  , _stack(copy_from->stack_size_for_copy(kind))

  , _locks(copy_from->locks_size() == 0 ? NULL : new Values(copy_from->locks_size()))

{

  assert(kind != EmptyExceptionState || !Compilation::current()->env()->should_retain_local_variables(), "need locals");

  if (kind != EmptyExceptionState) {

    _locals.appendAll(&copy_from->_locals);

  }

  if (kind != ExceptionState && kind != EmptyExceptionState) {

    _stack.appendAll(&copy_from->_stack);

  }

  if (copy_from->locks_size() > 0) {

    _locks->appendAll(copy_from->_locks);

  }

  verify();

}

int ValueStack::locals_size_for_copy(Kind kind) const {

  if (kind != EmptyExceptionState) {

    return locals_size();

  }

  return 0;

}

int ValueStack::stack_size_for_copy(Kind kind) const {

  if (kind != ExceptionState && kind != EmptyExceptionState) {

    if (kind == Parsing) {

      // stack will be modified, so reserve enough space to avoid resizing

      return scope()->method()->max_stack();

    } else {

      // stack will not be modified, so do not waste space

      return stack_size();

    }

  }

  return 0;

}

bool ValueStack::is_same(ValueStack* s) {

  if (scope() != s->scope()) return false;

  if (caller_state() != s->caller_state()) return false;

  if (locals_size() != s->locals_size()) return false;

  if (stack_size() != s->stack_size()) return false;

  if (locks_size() != s->locks_size()) return false;

  // compare each stack element with the corresponding stack element of s

  int index;

  Value value;

  for_each_stack_value(this, index, value) {

    if (value->type()->tag() != s->stack_at(index)->type()->tag()) return false;

  }

  for (int i = 0; i < locks_size(); i++) {

    value = lock_at(i);

    if (value != NULL && value != s->lock_at(i)) {

      return false;

    }

  }

  return true;

}

void ValueStack::clear_locals() {

  for (int i = _locals.length() - 1; i >= 0; i--) {

    _locals.at_put(i, NULL);

  }

}

void ValueStack::pin_stack_for_linear_scan() {

  for_each_state_value(this, v,

    if (v->as_Constant() == NULL && v->as_Local() == NULL) {

      v->pin(Instruction::PinStackForStateSplit);

    }

  );

}

// apply function to all values of a list; factored out from values_do(f)

void ValueStack::apply(const Values& list, ValueVisitor* f) {

  for (int i = 0; i < list.length(); i++) {

    Value* va = list.adr_at(i);

    Value v0 = *va;

    if (v0 != NULL && !v0->type()->is_illegal()) {

      f->visit(va);

#ifdef ASSERT

      Value v1 = *va;

      assert(v1->type()->is_illegal() || v0->type()->tag() == v1->type()->tag(), "types must match");

      assert(!v1->type()->is_double_word() || list.at(i + 1) == NULL, "hi-word of doubleword value must be NULL");

#endif

      if (v0->type()->is_double_word()) i++;

    }

  }

}

void ValueStack::values_do(ValueVisitor* f) {

  ValueStack* state = this;

  for_each_state(state) {

    apply(state->_locals, f);

    apply(state->_stack, f);

    if (state->_locks != NULL) {

      apply(*state->_locks, f);

    }

  }

}

Values* ValueStack::pop_arguments(int argument_size) {

  assert(stack_size() >= argument_size, "stack too small or too many arguments");

  int base = stack_size() - argument_size;

  Values* args = new Values(argument_size);

  for (int i = base; i < stack_size();) args->push(stack_at_inc(i));

  truncate_stack(base);

  return args;

}

int ValueStack::total_locks_size() const {

  int num_locks = 0;

  const ValueStack* state = this;

  for_each_state(state) {

    num_locks += state->locks_size();

  }

  return num_locks;

}

int ValueStack::lock(Value obj) {

  if (_locks == NULL) {

    _locks = new Values();

  }

  _locks->push(obj);

  int num_locks = total_locks_size();

  scope()->set_min_number_of_locks(num_locks);

  return num_locks - 1;

}

int ValueStack::unlock() {

  assert(locks_size() > 0, "sanity");

  _locks->pop();

  return total_locks_size();

}

void ValueStack::setup_phi_for_stack(BlockBegin* b, int index) {

  assert(stack_at(index)->as_Phi() == NULL || stack_at(index)->as_Phi()->block() != b, "phi function already created");

  ValueType* t = stack_at(index)->type();

  Value phi = new Phi(t, b, -index - 1);

  _stack.at_put(index, phi);

  assert(!t->is_double_word() || _stack.at(index + 1) == NULL, "hi-word of doubleword value must be NULL");

}

void ValueStack::setup_phi_for_local(BlockBegin* b, int index) {

  assert(local_at(index)->as_Phi() == NULL || local_at(index)->as_Phi()->block() != b, "phi function already created");

  ValueType* t = local_at(index)->type();

  Value phi = new Phi(t, b, index);

  store_local(index, phi);

}

#ifndef PRODUCT

void ValueStack::print() {

  scope()->method()->print_name();

  tty->cr();

  if (stack_is_empty()) {

    tty->print_cr("empty stack");

  } else {

    InstructionPrinter ip;

    for (int i = 0; i < stack_size();) {

      Value t = stack_at_inc(i);

      tty->print("%2d  ", i);

      tty->print("%c%d ", t->type()->tchar(), t->id());

      ip.print_instr(t);

      tty->cr();

    }

  }

  if (!no_active_locks()) {

    InstructionPrinter ip;

    for (int i = 0; i < locks_size(); i++) {

      Value t = lock_at(i);

      tty->print("lock %2d  ", i);

      if (t == NULL) {

        tty->print("this");

      } else {

        tty->print("%c%d ", t->type()->tchar(), t->id());

        ip.print_instr(t);

      }

      tty->cr();

    }

  }

  if (locals_size() > 0) {

    InstructionPrinter ip;

    for (int i = 0; i < locals_size();) {

      Value l = _locals.at(i);

      tty->print("local %d ", i);

      if (l == NULL) {

        tty->print("null");

        i ++;

      } else {

        tty->print("%c%d ", l->type()->tchar(), l->id());

        ip.print_instr(l);

        if (l->type()->is_illegal() || l->type()->is_single_word()) i ++; else i += 2;

      }

      tty->cr();

    }

  }

  if (caller_state() != NULL) {

    caller_state()->print();

  }

}

void ValueStack::verify() {

  assert(scope() != NULL, "scope must exist");

  if (caller_state() != NULL) {

    assert(caller_state()->scope() == scope()->caller(), "invalid caller scope");

    caller_state()->verify();

  }

  if (kind() == Parsing) {

    assert(bci() == -99, "bci not defined during parsing");

  } else {

    assert(bci() >= -1, "bci out of range");

    assert(bci() < scope()->method()->code_size(), "bci out of range");

    assert(bci() == SynchronizationEntryBCI || Bytecodes::is_defined(scope()->method()->java_code_at_bci(bci())), "make sure bci points at a real bytecode");

    assert(scope()->method()->liveness_at_bci(bci()).is_valid(), "liveness at bci must be valid");

  }

  int i;

  for (i = 0; i < stack_size(); i++) {

    Value v = _stack.at(i);

    if (v == NULL) {

      assert(_stack.at(i - 1)->type()->is_double_word(), "only hi-words are NULL on stack");

    } else if (v->type()->is_double_word()) {

      assert(_stack.at(i + 1) == NULL, "hi-word must be NULL");

    }

  }

  for (i = 0; i < locals_size(); i++) {

    Value v = _locals.at(i);

    if (v != NULL && v->type()->is_double_word()) {

      assert(_locals.at(i + 1) == NULL, "hi-word must be NULL");

    }

  }

  for_each_state_value(this, v,

    assert(v != NULL, "just test if state-iteration succeeds");

  );

}

#endif // PRODUCT