/*

 * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.

 * Copyright (c) 2012, 2015 SAP SE. 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 "asm/macroAssembler.inline.hpp"

#include "code/compiledIC.hpp"

#include "code/icBuffer.hpp"

#include "code/nmethod.hpp"

#include "memory/resourceArea.hpp"

#include "runtime/mutexLocker.hpp"

#include "runtime/safepoint.hpp"

#ifdef COMPILER2

#include "opto/matcher.hpp"

#endif

// ----------------------------------------------------------------------------

// A PPC CompiledDirectStaticCall looks like this:

//

// >>>> consts

//

// [call target1]

// [IC cache]

// [call target2]

//

// <<<< consts

// >>>> insts

//

// bl offset16               -+  -+             ??? // How many bits available?

//                            |   |

// <<<< insts                 |   |

// >>>> stubs                 |   |

//                            |   |- trampoline_stub_Reloc

// trampoline stub:           | <-+

//   r2 = toc                 |

//   r2 = [r2 + offset]       |       // Load call target1 from const section

//   mtctr r2                 |

//   bctr                     |- static_stub_Reloc

// comp_to_interp_stub:   <---+

//   r1 = toc

//   ICreg = [r1 + IC_offset]         // Load IC from const section

//   r1    = [r1 + offset]            // Load call target2 from const section

//   mtctr r1

//   bctr

//

// <<<< stubs

//

// The call instruction in the code either

// - branches directly to a compiled method if offset encodable in instruction

// - branches to the trampoline stub if offset to compiled method not encodable

// - branches to the compiled_to_interp stub if target interpreted

//

// Further there are three relocations from the loads to the constants in

// the constant section.

//

// Usage of r1 and r2 in the stubs allows to distinguish them.

const int IC_pos_in_java_to_interp_stub = 8;

#define __ _masm.

address CompiledStaticCall::emit_to_interp_stub(CodeBuffer &cbuf, address mark/* = NULL*/) {

#ifdef COMPILER2

  if (mark == NULL) {

    // Get the mark within main instrs section which is set to the address of the call.

    mark = cbuf.insts_mark();

  }

  // Note that the code buffer's insts_mark is always relative to insts.

  // That's why we must use the macroassembler to generate a stub.

  MacroAssembler _masm(&cbuf);

  // Start the stub.

  address stub = __ start_a_stub(CompiledStaticCall::to_interp_stub_size());

  if (stub == NULL) {

    return NULL; // CodeCache is full

  }

  // For java_to_interp stubs we use R11_scratch1 as scratch register

  // and in call trampoline stubs we use R12_scratch2. This way we

  // can distinguish them (see is_NativeCallTrampolineStub_at()).

  Register reg_scratch = R11_scratch1;

  // Create a static stub relocation which relates this stub

  // with the call instruction at insts_call_instruction_offset in the

  // instructions code-section.

  __ relocate(static_stub_Relocation::spec(mark));

  const int stub_start_offset = __ offset();

  // Now, create the stub's code:

  // - load the TOC

  // - load the inline cache oop from the constant pool

  // - load the call target from the constant pool

  // - call

  __ calculate_address_from_global_toc(reg_scratch, __ method_toc());

  AddressLiteral ic = __ allocate_metadata_address((Metadata *)NULL);

  bool success = __ load_const_from_method_toc(as_Register(Matcher::inline_cache_reg_encode()),

                                               ic, reg_scratch, /*fixed_size*/ true);

  if (!success) {

    return NULL; // CodeCache is full

  }

  if (ReoptimizeCallSequences) {

    __ b64_patchable((address)-1, relocInfo::none);

  } else {

    AddressLiteral a((address)-1);

    success = __ load_const_from_method_toc(reg_scratch, a, reg_scratch, /*fixed_size*/ true);

    if (!success) {

      return NULL; // CodeCache is full

    }

    __ mtctr(reg_scratch);

    __ bctr();

  }

  // FIXME: Assert that the stub can be identified and patched.

  // Java_to_interp_stub_size should be good.

  assert((__ offset() - stub_start_offset) <= CompiledStaticCall::to_interp_stub_size(),

         "should be good size");

  assert(!is_NativeCallTrampolineStub_at(__ addr_at(stub_start_offset)),

         "must not confuse java_to_interp with trampoline stubs");

 // End the stub.

  __ end_a_stub();

  return stub;

#else

  ShouldNotReachHere();

  return NULL;

#endif

}

#undef __

// Size of java_to_interp stub, this doesn't need to be accurate but it must

// be larger or equal to the real size of the stub.

// Used for optimization in Compile::Shorten_branches.

int CompiledStaticCall::to_interp_stub_size() {

  return 12 * BytesPerInstWord;

}

// Relocation entries for call stub, compiled java to interpreter.

// Used for optimization in Compile::Shorten_branches.

int CompiledStaticCall::reloc_to_interp_stub() {

  return 5;

}

void CompiledDirectStaticCall::set_to_interpreted(const methodHandle& callee, address entry) {

  address stub = find_stub(/*is_aot*/ false);

  guarantee(stub != NULL, "stub not found");

  if (TraceICs) {

    ResourceMark rm;

    tty->print_cr("CompiledDirectStaticCall@" INTPTR_FORMAT ": set_to_interpreted %s",

                  p2i(instruction_address()),

                  callee->name_and_sig_as_C_string());

  }

  // Creation also verifies the object.

  NativeMovConstReg* method_holder = nativeMovConstReg_at(stub + IC_pos_in_java_to_interp_stub);

  NativeJump*        jump          = nativeJump_at(method_holder->next_instruction_address());

#ifdef ASSERT

  // read the value once

  volatile intptr_t data = method_holder->data();

  volatile address destination = jump->jump_destination();

  assert(data == 0 || data == (intptr_t)callee(),

         "a) MT-unsafe modification of inline cache");

  assert(destination == (address)-1 || destination == entry,

         "b) MT-unsafe modification of inline cache");

#endif

  // Update stub.

  method_holder->set_data((intptr_t)callee());

  jump->set_jump_destination(entry);

  // Update jump to call.

  set_destination_mt_safe(stub);

}

void CompiledDirectStaticCall::set_stub_to_clean(static_stub_Relocation* static_stub) {

  assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "mt unsafe call");

  // Reset stub.

  address stub = static_stub->addr();

  assert(stub != NULL, "stub not found");

  // Creation also verifies the object.

  NativeMovConstReg* method_holder = nativeMovConstReg_at(stub + IC_pos_in_java_to_interp_stub);

  NativeJump*        jump          = nativeJump_at(method_holder->next_instruction_address());

  method_holder->set_data(0);

  jump->set_jump_destination((address)-1);

}

//-----------------------------------------------------------------------------

// Non-product mode code

#ifndef PRODUCT

void CompiledDirectStaticCall::verify() {

  // Verify call.

  _call->verify();

  if (os::is_MP()) {

    _call->verify_alignment();

  }

  // Verify stub.

  address stub = find_stub(/*is_aot*/ false);

  assert(stub != NULL, "no stub found for static call");

  // Creation also verifies the object.

  NativeMovConstReg* method_holder = nativeMovConstReg_at(stub + IC_pos_in_java_to_interp_stub);

  NativeJump*        jump          = nativeJump_at(method_holder->next_instruction_address());

  // Verify state.

  assert(is_clean() || is_call_to_compiled() || is_call_to_interpreted(), "sanity check");

}

#endif // !PRODUCT