/*

 * Copyright (c) 2014, Red Hat Inc. 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_MacroAssembler.hpp"

#include "c1/c1_Runtime1.hpp"

#include "classfile/systemDictionary.hpp"

#include "interpreter/interpreter.hpp"

#include "oops/arrayOop.hpp"

#include "oops/markOop.hpp"

#include "runtime/basicLock.hpp"

#include "runtime/biasedLocking.hpp"

#include "runtime/os.hpp"

#include "runtime/sharedRuntime.hpp"

#include "runtime/stubRoutines.hpp"

void C1_MacroAssembler::float_cmp(bool is_float, int unordered_result,

                                  FloatRegister f0, FloatRegister f1,

                                  Register result)

{

  Label done;

  if (is_float) {

    fcmps(f0, f1);

  } else {

    fcmpd(f0, f1);

  }

  if (unordered_result < 0) {

    // we want -1 for unordered or less than, 0 for equal and 1 for

    // greater than.

    cset(result, NE);  // Not equal or unordered

    cneg(result, result, LT);  // Less than or unordered

  } else {

    // we want -1 for less than, 0 for equal and 1 for unordered or

    // greater than.

    cset(result, NE);  // Not equal or unordered

    cneg(result, result, LO);  // Less than

  }

}

int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register scratch, Label& slow_case) {

  const int aligned_mask = BytesPerWord -1;

  const int hdr_offset = oopDesc::mark_offset_in_bytes();

  assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");

  Label done, fail;

  int null_check_offset = -1;

  verify_oop(obj);

  // save object being locked into the BasicObjectLock

  str(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));

  if (UseBiasedLocking) {

    assert(scratch != noreg, "should have scratch register at this point");

    null_check_offset = biased_locking_enter(disp_hdr, obj, hdr, scratch, false, done, &slow_case);

  } else {

    null_check_offset = offset();

  }

  // Load object header

  ldr(hdr, Address(obj, hdr_offset));

  // and mark it as unlocked

  orr(hdr, hdr, markOopDesc::unlocked_value);

  // save unlocked object header into the displaced header location on the stack

  str(hdr, Address(disp_hdr, 0));

  // test if object header is still the same (i.e. unlocked), and if so, store the

  // displaced header address in the object header - if it is not the same, get the

  // object header instead

  lea(rscratch2, Address(obj, hdr_offset));

  cmpxchgptr(hdr, disp_hdr, rscratch2, rscratch1, done, /*fallthough*/NULL);

  // if the object header was the same, we're done

  // if the object header was not the same, it is now in the hdr register

  // => test if it is a stack pointer into the same stack (recursive locking), i.e.:

  //

  // 1) (hdr & aligned_mask) == 0

  // 2) sp <= hdr

  // 3) hdr <= sp + page_size

  //

  // these 3 tests can be done by evaluating the following expression:

  //

  // (hdr - sp) & (aligned_mask - page_size)

  //

  // assuming both the stack pointer and page_size have their least

  // significant 2 bits cleared and page_size is a power of 2

  mov(rscratch1, sp);

  sub(hdr, hdr, rscratch1);

  ands(hdr, hdr, aligned_mask - os::vm_page_size());

  // for recursive locking, the result is zero => save it in the displaced header

  // location (NULL in the displaced hdr location indicates recursive locking)

  str(hdr, Address(disp_hdr, 0));

  // otherwise we don't care about the result and handle locking via runtime call

  cbnz(hdr, slow_case);

  // done

  bind(done);

  if (PrintBiasedLockingStatistics) {

    lea(rscratch2, ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr()));

    addmw(Address(rscratch2, 0), 1, rscratch1);

  }

  return null_check_offset;

}

void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {

  const int aligned_mask = BytesPerWord -1;

  const int hdr_offset = oopDesc::mark_offset_in_bytes();

  assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");

  Label done;

  if (UseBiasedLocking) {

    // load object

    ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));

    biased_locking_exit(obj, hdr, done);

  }

  // load displaced header

  ldr(hdr, Address(disp_hdr, 0));

  // if the loaded hdr is NULL we had recursive locking

  // if we had recursive locking, we are done

  cbz(hdr, done);

  if (!UseBiasedLocking) {

    // load object

    ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));

  }

  verify_oop(obj);

  // test if object header is pointing to the displaced header, and if so, restore

  // the displaced header in the object - if the object header is not pointing to

  // the displaced header, get the object header instead

  // if the object header was not pointing to the displaced header,

  // we do unlocking via runtime call

  if (hdr_offset) {

    lea(rscratch1, Address(obj, hdr_offset));

    cmpxchgptr(disp_hdr, hdr, rscratch1, rscratch2, done, &slow_case);

  } else {

    cmpxchgptr(disp_hdr, hdr, obj, rscratch2, done, &slow_case);

  }

  // done

  bind(done);

}

// Defines obj, preserves var_size_in_bytes

void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {

  if (UseTLAB) {

    tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);

  } else {

    eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case);

    incr_allocated_bytes(noreg, var_size_in_bytes, con_size_in_bytes, t1);

  }

}

void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {

  assert_different_registers(obj, klass, len);

  if (UseBiasedLocking && !len->is_valid()) {

    assert_different_registers(obj, klass, len, t1, t2);

    ldr(t1, Address(klass, Klass::prototype_header_offset()));

  } else {

    // This assumes that all prototype bits fit in an int32_t

    mov(t1, (int32_t)(intptr_t)markOopDesc::prototype());

  }

  str(t1, Address(obj, oopDesc::mark_offset_in_bytes()));

  if (UseCompressedClassPointers) { // Take care not to kill klass

    encode_klass_not_null(t1, klass);

    strw(t1, Address(obj, oopDesc::klass_offset_in_bytes()));

  } else {

    str(klass, Address(obj, oopDesc::klass_offset_in_bytes()));

  }

  if (len->is_valid()) {

    strw(len, Address(obj, arrayOopDesc::length_offset_in_bytes()));

  } else if (UseCompressedClassPointers) {

    store_klass_gap(obj, zr);

  }

}

// Zero words; len is in bytes

// Destroys all registers except addr

// len must be a nonzero multiple of wordSize

void C1_MacroAssembler::zero_memory(Register addr, Register len, Register t1) {

  assert_different_registers(addr, len, t1, rscratch1, rscratch2);

#ifdef ASSERT

  { Label L;

    tst(len, BytesPerWord - 1);

    br(Assembler::EQ, L);

    stop("len is not a multiple of BytesPerWord");

    bind(L);

  }

#endif

#ifndef PRODUCT

  block_comment("zero memory");

#endif

  Label loop;

  Label entry;

//  Algorithm:

//

//    scratch1 = cnt & 7;

//    cnt -= scratch1;

//    p += scratch1;

//    switch (scratch1) {

//      do {

//        cnt -= 8;

//          p[-8] = 0;

//        case 7:

//          p[-7] = 0;

//        case 6:

//          p[-6] = 0;

//          // ...

//        case 1:

//          p[-1] = 0;

//        case 0:

//          p += 8;

//      } while (cnt);

//    }

  const int unroll = 8; // Number of str(zr) instructions we'll unroll

  lsr(len, len, LogBytesPerWord);

  andr(rscratch1, len, unroll - 1);  // tmp1 = cnt % unroll

  sub(len, len, rscratch1);      // cnt -= unroll

  // t1 always points to the end of the region we're about to zero

  add(t1, addr, rscratch1, Assembler::LSL, LogBytesPerWord);

  adr(rscratch2, entry);

  sub(rscratch2, rscratch2, rscratch1, Assembler::LSL, 2);

  br(rscratch2);

  bind(loop);

  sub(len, len, unroll);

  for (int i = -unroll; i < 0; i++)

    str(zr, Address(t1, i * wordSize));

  bind(entry);

  add(t1, t1, unroll * wordSize);

  cbnz(len, loop);

}

// preserves obj, destroys len_in_bytes

void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {

  Label done;

  assert(obj != len_in_bytes && obj != t1 && t1 != len_in_bytes, "registers must be different");

  assert((hdr_size_in_bytes & (BytesPerWord - 1)) == 0, "header size is not a multiple of BytesPerWord");

  Register index = len_in_bytes;

  // index is positive and ptr sized

  subs(index, index, hdr_size_in_bytes);

  br(Assembler::EQ, done);

  // note: for the remaining code to work, index must be a multiple of BytesPerWord

#ifdef ASSERT

  { Label L;

    tst(index, BytesPerWord - 1);

    br(Assembler::EQ, L);

    stop("index is not a multiple of BytesPerWord");

    bind(L);

  }

#endif

  // Preserve obj

  if (hdr_size_in_bytes)

    add(obj, obj, hdr_size_in_bytes);

  zero_memory(obj, index, t1);

  if (hdr_size_in_bytes)

    sub(obj, obj, hdr_size_in_bytes);

  // done

  bind(done);

}

void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {

  assert_different_registers(obj, t1, t2); // XXX really?

  assert(header_size >= 0 && object_size >= header_size, "illegal sizes");

  try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);

  initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2);

}

void C1_MacroAssembler::initialize_object(Register obj, Register klass, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2) {

  assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,

         "con_size_in_bytes is not multiple of alignment");

  const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;

  initialize_header(obj, klass, noreg, t1, t2);

  // clear rest of allocated space

  const Register index = t2;

  const int threshold = 16 * BytesPerWord;   // approximate break even point for code size (see comments below)

  if (var_size_in_bytes != noreg) {

    mov(index, var_size_in_bytes);

    initialize_body(obj, index, hdr_size_in_bytes, t1);

  } else if (con_size_in_bytes <= threshold) {

    // use explicit null stores

    int i = hdr_size_in_bytes;

    if (i < con_size_in_bytes && (con_size_in_bytes % (2 * BytesPerWord))) {

      str(zr, Address(obj, i));

      i += BytesPerWord;

    }

    for (; i < con_size_in_bytes; i += 2 * BytesPerWord)

      stp(zr, zr, Address(obj, i));

  } else if (con_size_in_bytes > hdr_size_in_bytes) {

    block_comment("zero memory");

    // use loop to null out the fields

    int words = (con_size_in_bytes - hdr_size_in_bytes) / BytesPerWord;

    mov(index,  words / 8);

    const int unroll = 8; // Number of str(zr) instructions we'll unroll

    int remainder = words % unroll;

    lea(rscratch1, Address(obj, hdr_size_in_bytes + remainder * BytesPerWord));

    Label entry_point, loop;

    b(entry_point);

    bind(loop);

    sub(index, index, 1);

    for (int i = -unroll; i < 0; i++) {

      if (-i == remainder)

        bind(entry_point);

      str(zr, Address(rscratch1, i * wordSize));

    }

    if (remainder == 0)

      bind(entry_point);

    add(rscratch1, rscratch1, unroll * wordSize);

    cbnz(index, loop);

  }

  membar(StoreStore);

  if (CURRENT_ENV->dtrace_alloc_probes()) {

    assert(obj == r0, "must be");

    far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));

  }

  verify_oop(obj);

}

void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, int f, Register klass, Label& slow_case) {

  assert_different_registers(obj, len, t1, t2, klass);

  // determine alignment mask

  assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");

  // check for negative or excessive length

  mov(rscratch1, (int32_t)max_array_allocation_length);

  cmp(len, rscratch1);

  br(Assembler::HS, slow_case);

  const Register arr_size = t2; // okay to be the same

  // align object end

  mov(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask);

  add(arr_size, arr_size, len, ext::uxtw, f);

  andr(arr_size, arr_size, ~MinObjAlignmentInBytesMask);

  try_allocate(obj, arr_size, 0, t1, t2, slow_case);

  initialize_header(obj, klass, len, t1, t2);

  // clear rest of allocated space

  const Register len_zero = len;

  initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero);

  membar(StoreStore);

  if (CURRENT_ENV->dtrace_alloc_probes()) {

    assert(obj == r0, "must be");

    far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));

  }

  verify_oop(obj);

}

void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {

  verify_oop(receiver);

  // explicit NULL check not needed since load from [klass_offset] causes a trap

  // check against inline cache

  assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");

  cmp_klass(receiver, iCache, rscratch1);

}

void C1_MacroAssembler::build_frame(int framesize, int bang_size_in_bytes) {

  // If we have to make this method not-entrant we'll overwrite its

  // first instruction with a jump.  For this action to be legal we

  // must ensure that this first instruction is a B, BL, NOP, BKPT,

  // SVC, HVC, or SMC.  Make it a NOP.

  nop();

  assert(bang_size_in_bytes >= framesize, "stack bang size incorrect");

  // Make sure there is enough stack space for this method's activation.

  // Note that we do this before doing an enter().

  generate_stack_overflow_check(bang_size_in_bytes);

  MacroAssembler::build_frame(framesize + 2 * wordSize);

  if (NotifySimulator) {

    notify(Assembler::method_entry);

  }

}

void C1_MacroAssembler::remove_frame(int framesize) {

  MacroAssembler::remove_frame(framesize + 2 * wordSize);

  if (NotifySimulator) {

    notify(Assembler::method_reentry);

  }

}

void C1_MacroAssembler::verified_entry() {

}

#ifndef PRODUCT

void C1_MacroAssembler::verify_stack_oop(int stack_offset) {

  if (!VerifyOops) return;

  verify_oop_addr(Address(sp, stack_offset), "oop");

}

void C1_MacroAssembler::verify_not_null_oop(Register r) {

  if (!VerifyOops) return;

  Label not_null;

  cbnz(r, not_null);

  stop("non-null oop required");

  bind(not_null);

  verify_oop(r);

}

void C1_MacroAssembler::invalidate_registers(bool inv_r0, bool inv_r19, bool inv_r2, bool inv_r3, bool inv_r4, bool inv_r5) {

#ifdef ASSERT

  static int nn;

  if (inv_r0) mov(r0, 0xDEAD);

  if (inv_r19) mov(r19, 0xDEAD);

  if (inv_r2) mov(r2, nn++);

  if (inv_r3) mov(r3, 0xDEAD);

  if (inv_r4) mov(r4, 0xDEAD);

  if (inv_r5) mov(r5, 0xDEAD);

#endif

}

#endif // ifndef PRODUCT