/*

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

 * Copyright 2009 Red Hat, Inc.

 * 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 "ci/ciField.hpp"

#include "ci/ciMethod.hpp"

#include "ci/ciStreams.hpp"

#include "interpreter/bytecodes.hpp"

#include "memory/allocation.hpp"

#include "memory/resourceArea.hpp"

#include "shark/sharkBlock.hpp"

#include "shark/sharkConstant.hpp"

#include "shark/sharkInliner.hpp"

#include "shark/sharkIntrinsics.hpp"

#include "shark/sharkState.hpp"

#include "shark/sharkValue.hpp"

#include "shark/shark_globals.hpp"

using namespace llvm;

class SharkInlineBlock : public SharkBlock {

 public:

  SharkInlineBlock(ciMethod* target, SharkState* state)

    : SharkBlock(state, target),

      _outer_state(state),

      _entry_state(new SharkState(this)) {

    for (int i = target->max_locals() - 1; i >= 0; i--) {

      SharkValue *value = NULL;

      if (i < target->arg_size())

        value = outer_state()->pop();

      entry_state()->set_local(i, value);

    }

  }

 private:

  SharkState* _outer_state;

  SharkState* _entry_state;

 private:

  SharkState* outer_state() {

    return _outer_state;

  }

  SharkState* entry_state() {

    return _entry_state;

  }

 public:

  void emit_IR() {

    parse_bytecode(0, target()->code_size());

  }

 private:

  void do_return(BasicType type) {

    if (type != T_VOID) {

      SharkValue *result = pop_result(type);

      outer_state()->push(result);

      if (result->is_two_word())

        outer_state()->push(NULL);

    }

  }

};

class SharkInlinerHelper : public StackObj {

 public:

  SharkInlinerHelper(ciMethod* target, SharkState* entry_state)

    : _target(target),

      _entry_state(entry_state),

      _iter(target) {}

 private:

  ciBytecodeStream _iter;

  SharkState*      _entry_state;

  ciMethod*        _target;

 public:

  ciBytecodeStream* iter() {

    return &_iter;

  }

  SharkState* entry_state() const {

    return _entry_state;

  }

  ciMethod* target() const {

    return _target;

  }

 public:

  Bytecodes::Code bc() {

    return iter()->cur_bc();

  }

  int max_locals() const {

    return target()->max_locals();

  }

  int max_stack() const {

    return target()->max_stack();

  }

  // Inlinability check

 public:

  bool is_inlinable();

 private:

  void initialize_for_check();

  bool do_getstatic() {

    return do_field_access(true, false);

  }

  bool do_getfield() {

    return do_field_access(true, true);

  }

  bool do_putfield() {

    return do_field_access(false, true);

  }

  bool do_field_access(bool is_get, bool is_field);

  // Local variables for inlinability check

 private:

  bool* _locals;

 public:

  bool* local_addr(int index) const {

    assert(index >= 0 && index < max_locals(), "bad local variable index");

    return &_locals[index];

  }

  bool local(int index) const {

    return *local_addr(index);

  }

  void set_local(int index, bool value) {

    *local_addr(index) = value;

  }

  // Expression stack for inlinability check

 private:

  bool* _stack;

  bool* _sp;

 public:

  int stack_depth() const {

    return _sp - _stack;

  }

  bool* stack_addr(int slot) const {

    assert(slot >= 0 && slot < stack_depth(), "bad stack slot");

    return &_sp[-(slot + 1)];

  }

  void push(bool value) {

    assert(stack_depth() < max_stack(), "stack overrun");

    *(_sp++) = value;

  }

  bool pop() {

    assert(stack_depth() > 0, "stack underrun");

    return *(--_sp);

  }

  // Methods for two-word locals

 public:

  void push_pair_local(int index) {

    push(local(index));

    push(local(index + 1));

  }

  void pop_pair_local(int index) {

    set_local(index + 1, pop());

    set_local(index, pop());

  }

  // Code generation

 public:

  void do_inline() {

    (new SharkInlineBlock(target(), entry_state()))->emit_IR();

  }

};

// Quick checks so we can bail out before doing too much

bool SharkInliner::may_be_inlinable(ciMethod *target) {

  // We can't inline native methods

  if (target->is_native())

    return false;

  // Not much point inlining abstract ones, and in any

  // case we'd need a stack frame to throw the exception

  if (target->is_abstract())

    return false;

  // Don't inline anything huge

  if (target->code_size() > SharkMaxInlineSize)

    return false;

  // Monitors aren't allowed without a frame to put them in

  if (target->is_synchronized() || target->has_monitor_bytecodes())

    return false;

  // We don't do control flow

  if (target->has_exception_handlers() || target->has_jsrs())

    return false;

  // Don't try to inline constructors, as they must

  // eventually call Object.<init> which we can't inline.

  // Note that this catches <clinit> too, but why would

  // we be compiling that?

  if (target->is_initializer())

    return false;

  // Mustn't inline Object.<init>

  // Should be caught by the above, but just in case...

  if (target->intrinsic_id() == vmIntrinsics::_Object_init)

    return false;

  return true;

}

// Full-on detailed check, for methods that pass the quick checks

// Inlined methods have no stack frame, so we can't do anything

// that would require one.  This means no safepoints (and hence

// no loops) and no VM calls.  No VM calls means, amongst other

// things, that no exceptions can be created, which means no null

// checks or divide-by-zero checks are allowed.  The lack of null

// checks in particular would eliminate practically everything,

// but we can get around that restriction by relying on the zero-

// check eliminator to strip the checks.  To do that, we need to

// walk through the method, tracking which values are and are not

// zero-checked.

bool SharkInlinerHelper::is_inlinable() {

  ResourceMark rm;

  initialize_for_check();

  SharkConstant *sc;

  bool a, b, c, d;

  iter()->reset_to_bci(0);

  while (iter()->next() != ciBytecodeStream::EOBC()) {

    switch (bc()) {

    case Bytecodes::_nop:

      break;

    case Bytecodes::_aconst_null:

      push(false);

      break;

    case Bytecodes::_iconst_0:

      push(false);

      break;

    case Bytecodes::_iconst_m1:

    case Bytecodes::_iconst_1:

    case Bytecodes::_iconst_2:

    case Bytecodes::_iconst_3:

    case Bytecodes::_iconst_4:

    case Bytecodes::_iconst_5:

      push(true);

      break;

    case Bytecodes::_lconst_0:

      push(false);

      push(false);

      break;

    case Bytecodes::_lconst_1:

      push(true);

      push(false);

      break;

    case Bytecodes::_fconst_0:

    case Bytecodes::_fconst_1:

    case Bytecodes::_fconst_2:

      push(false);

      break;

    case Bytecodes::_dconst_0:

    case Bytecodes::_dconst_1:

      push(false);

      push(false);

      break;

    case Bytecodes::_bipush:

      push(iter()->get_constant_u1() != 0);

      break;

    case Bytecodes::_sipush:

      push(iter()->get_constant_u2() != 0);

      break;

    case Bytecodes::_ldc:

    case Bytecodes::_ldc_w:

    case Bytecodes::_ldc2_w:

      sc = SharkConstant::for_ldc(iter());

      if (!sc->is_loaded())

        return false;

      push(sc->is_nonzero());

      if (sc->is_two_word())

        push(false);

      break;

    case Bytecodes::_iload_0:

    case Bytecodes::_fload_0:

    case Bytecodes::_aload_0:

      push(local(0));

      break;

    case Bytecodes::_lload_0:

    case Bytecodes::_dload_0:

      push_pair_local(0);

      break;

    case Bytecodes::_iload_1:

    case Bytecodes::_fload_1:

    case Bytecodes::_aload_1:

      push(local(1));

      break;

    case Bytecodes::_lload_1:

    case Bytecodes::_dload_1:

      push_pair_local(1);

      break;

    case Bytecodes::_iload_2:

    case Bytecodes::_fload_2:

    case Bytecodes::_aload_2:

      push(local(2));

      break;

    case Bytecodes::_lload_2:

    case Bytecodes::_dload_2:

      push_pair_local(2);

      break;

    case Bytecodes::_iload_3:

    case Bytecodes::_fload_3:

    case Bytecodes::_aload_3:

      push(local(3));

      break;

    case Bytecodes::_lload_3:

    case Bytecodes::_dload_3:

      push_pair_local(3);

      break;

    case Bytecodes::_iload:

    case Bytecodes::_fload:

    case Bytecodes::_aload:

      push(local(iter()->get_index()));

      break;

    case Bytecodes::_lload:

    case Bytecodes::_dload:

      push_pair_local(iter()->get_index());

      break;

    case Bytecodes::_istore_0:

    case Bytecodes::_fstore_0:

    case Bytecodes::_astore_0:

      set_local(0, pop());

      break;

    case Bytecodes::_lstore_0:

    case Bytecodes::_dstore_0:

      pop_pair_local(0);

      break;

    case Bytecodes::_istore_1:

    case Bytecodes::_fstore_1:

    case Bytecodes::_astore_1:

      set_local(1, pop());

      break;

    case Bytecodes::_lstore_1:

    case Bytecodes::_dstore_1:

      pop_pair_local(1);

      break;

    case Bytecodes::_istore_2:

    case Bytecodes::_fstore_2:

    case Bytecodes::_astore_2:

      set_local(2, pop());

      break;

    case Bytecodes::_lstore_2:

    case Bytecodes::_dstore_2:

      pop_pair_local(2);

      break;

    case Bytecodes::_istore_3:

    case Bytecodes::_fstore_3:

    case Bytecodes::_astore_3:

      set_local(3, pop());

      break;

    case Bytecodes::_lstore_3:

    case Bytecodes::_dstore_3:

      pop_pair_local(3);

      break;

    case Bytecodes::_istore:

    case Bytecodes::_fstore:

    case Bytecodes::_astore:

      set_local(iter()->get_index(), pop());

      break;

    case Bytecodes::_lstore:

    case Bytecodes::_dstore:

      pop_pair_local(iter()->get_index());

      break;

    case Bytecodes::_pop:

      pop();

      break;

    case Bytecodes::_pop2:

      pop();

      pop();

      break;

    case Bytecodes::_swap:

      a = pop();

      b = pop();

      push(a);

      push(b);

      break;

    case Bytecodes::_dup:

      a = pop();

      push(a);

      push(a);

      break;

    case Bytecodes::_dup_x1:

      a = pop();

      b = pop();

      push(a);

      push(b);

      push(a);

      break;

    case Bytecodes::_dup_x2:

      a = pop();

      b = pop();

      c = pop();

      push(a);

      push(c);

      push(b);

      push(a);

      break;

    case Bytecodes::_dup2:

      a = pop();

      b = pop();

      push(b);

      push(a);

      push(b);

      push(a);

      break;

    case Bytecodes::_dup2_x1:

      a = pop();

      b = pop();

      c = pop();

      push(b);

      push(a);

      push(c);

      push(b);

      push(a);

      break;

    case Bytecodes::_dup2_x2:

      a = pop();

      b = pop();

      c = pop();

      d = pop();

      push(b);

      push(a);

      push(d);

      push(c);

      push(b);

      push(a);

      break;

    case Bytecodes::_getfield:

      if (!do_getfield())

        return false;

      break;

    case Bytecodes::_getstatic:

      if (!do_getstatic())

        return false;

      break;

    case Bytecodes::_putfield:

      if (!do_putfield())

        return false;

      break;

    case Bytecodes::_iadd:

    case Bytecodes::_isub:

    case Bytecodes::_imul:

    case Bytecodes::_iand:

    case Bytecodes::_ixor:

    case Bytecodes::_ishl:

    case Bytecodes::_ishr:

    case Bytecodes::_iushr:

      pop();

      pop();

      push(false);

      break;

    case Bytecodes::_ior:

      a = pop();

      b = pop();

      push(a && b);

      break;

    case Bytecodes::_idiv:

    case Bytecodes::_irem:

      if (!pop())

        return false;

      pop();

      push(false);

      break;

    case Bytecodes::_ineg:

      break;

    case Bytecodes::_ladd:

    case Bytecodes::_lsub:

    case Bytecodes::_lmul:

    case Bytecodes::_land:

    case Bytecodes::_lxor:

      pop();

      pop();

      pop();

      pop();

      push(false);

      push(false);

      break;

    case Bytecodes::_lor: