/*
 * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2012, 2018 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 "c1/c1_MacroAssembler.hpp"
#include "c1/c1_Runtime1.hpp"
#include "classfile/systemDictionary.hpp"
#include "gc/shared/collectedHeap.hpp"
#include "interpreter/interpreter.hpp"
#include "oops/arrayOop.hpp"
#include "oops/markWord.hpp"
#include "runtime/basicLock.hpp"
#include "runtime/biasedLocking.hpp"
#include "runtime/os.hpp"
#include "runtime/sharedRuntime.hpp"
#include "runtime/stubRoutines.hpp"
#include "utilities/align.hpp"


void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
  const Register temp_reg = R12_scratch2;
  Label Lmiss;

  verify_oop(receiver);
  MacroAssembler::null_check(receiver, oopDesc::klass_offset_in_bytes(), &Lmiss);
  load_klass(temp_reg, receiver);

  if (TrapBasedICMissChecks && TrapBasedNullChecks) {
    trap_ic_miss_check(temp_reg, iCache);
  } else {
    Label Lok;
    cmpd(CCR0, temp_reg, iCache);
    beq(CCR0, Lok);
    bind(Lmiss);
    //load_const_optimized(temp_reg, SharedRuntime::get_ic_miss_stub(), R0);
    calculate_address_from_global_toc(temp_reg, SharedRuntime::get_ic_miss_stub(), true, true, false);
    mtctr(temp_reg);
    bctr();
    align(32, 12);
    bind(Lok);
  }
}


void C1_MacroAssembler::explicit_null_check(Register base) {
  Unimplemented();
}


void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes) {
  // Avoid stack bang as first instruction. It may get overwritten by patch_verified_entry.
  const Register return_pc = R20;
  mflr(return_pc);

  // Make sure there is enough stack space for this method's activation.
  assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect");
  generate_stack_overflow_check(bang_size_in_bytes);

  std(return_pc, _abi(lr), R1_SP);     // SP->lr = return_pc
  push_frame(frame_size_in_bytes, R0); // SP -= frame_size_in_bytes
}


void C1_MacroAssembler::verified_entry() {
  if (C1Breakpoint) illtrap();
  // build frame
}


void C1_MacroAssembler::lock_object(Register Rmark, Register Roop, Register Rbox, Register Rscratch, Label& slow_case) {
  assert_different_registers(Rmark, Roop, Rbox, Rscratch);

  Label done, cas_failed, slow_int;

  // The following move must be the first instruction of emitted since debug
  // information may be generated for it.
  // Load object header.
  ld(Rmark, oopDesc::mark_offset_in_bytes(), Roop);

  verify_oop(Roop);

  // Save object being locked into the BasicObjectLock...
  std(Roop, BasicObjectLock::obj_offset_in_bytes(), Rbox);

  if (UseBiasedLocking) {
    biased_locking_enter(CCR0, Roop, Rmark, Rscratch, R0, done, &slow_int);
  }

  // ... and mark it unlocked.
  ori(Rmark, Rmark, markWord::unlocked_value);

  // Save unlocked object header into the displaced header location on the stack.
  std(Rmark, BasicLock::displaced_header_offset_in_bytes(), Rbox);

  // Compare object markWord with Rmark and if equal exchange Rscratch with object markWord.
  assert(oopDesc::mark_offset_in_bytes() == 0, "cas must take a zero displacement");
  cmpxchgd(/*flag=*/CCR0,
           /*current_value=*/Rscratch,
           /*compare_value=*/Rmark,
           /*exchange_value=*/Rbox,
           /*where=*/Roop/*+0==mark_offset_in_bytes*/,
           MacroAssembler::MemBarRel | MacroAssembler::MemBarAcq,
           MacroAssembler::cmpxchgx_hint_acquire_lock(),
           noreg,
           &cas_failed,
           /*check without membar and ldarx first*/true);
  // If compare/exchange succeeded we found an unlocked object and we now have locked it
  // hence we are done.
  b(done);

  bind(slow_int);
  b(slow_case); // far

  bind(cas_failed);
  // We did not find an unlocked object so see if this is a recursive case.
  sub(Rscratch, Rscratch, R1_SP);
  load_const_optimized(R0, (~(os::vm_page_size()-1) | markWord::lock_mask_in_place));
  and_(R0/*==0?*/, Rscratch, R0);
  std(R0/*==0, perhaps*/, BasicLock::displaced_header_offset_in_bytes(), Rbox);
  bne(CCR0, slow_int);

  bind(done);
}


void C1_MacroAssembler::unlock_object(Register Rmark, Register Roop, Register Rbox, Label& slow_case) {
  assert_different_registers(Rmark, Roop, Rbox);

  Label slow_int, done;

  Address mark_addr(Roop, oopDesc::mark_offset_in_bytes());
  assert(mark_addr.disp() == 0, "cas must take a zero displacement");

  if (UseBiasedLocking) {
    // Load the object out of the BasicObjectLock.
    ld(Roop, BasicObjectLock::obj_offset_in_bytes(), Rbox);
    verify_oop(Roop);
    biased_locking_exit(CCR0, Roop, R0, done);
  }
  // Test first it it is a fast recursive unlock.
  ld(Rmark, BasicLock::displaced_header_offset_in_bytes(), Rbox);
  cmpdi(CCR0, Rmark, 0);
  beq(CCR0, done);
  if (!UseBiasedLocking) {
    // Load object.
    ld(Roop, BasicObjectLock::obj_offset_in_bytes(), Rbox);
    verify_oop(Roop);
  }

  // Check if it is still a light weight lock, this is is true if we see
  // the stack address of the basicLock in the markWord of the object.
  cmpxchgd(/*flag=*/CCR0,
           /*current_value=*/R0,
           /*compare_value=*/Rbox,
           /*exchange_value=*/Rmark,
           /*where=*/Roop,
           MacroAssembler::MemBarRel,
           MacroAssembler::cmpxchgx_hint_release_lock(),
           noreg,
           &slow_int);
  b(done);
  bind(slow_int);
  b(slow_case); // far

  // Done
  bind(done);
}


void C1_MacroAssembler::try_allocate(
  Register obj,                        // result: pointer to object after successful allocation
  Register var_size_in_bytes,          // object size in bytes if unknown at compile time; invalid otherwise
  int      con_size_in_bytes,          // object size in bytes if   known at compile time
  Register t1,                         // temp register, must be global register for incr_allocated_bytes
  Register t2,                         // temp register
  Label&   slow_case                   // continuation point if fast allocation fails
) {
  if (UseTLAB) {
    tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case);
  } else {
    eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
    RegisterOrConstant size_in_bytes = var_size_in_bytes->is_valid()
                                       ? RegisterOrConstant(var_size_in_bytes)
                                       : RegisterOrConstant(con_size_in_bytes);
    incr_allocated_bytes(size_in_bytes, t1, t2);
  }
}


void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
  assert_different_registers(obj, klass, len, t1, t2);
  if (UseBiasedLocking && !len->is_valid()) {
    ld(t1, in_bytes(Klass::prototype_header_offset()), klass);
  } else {
    load_const_optimized(t1, (intx)markWord::prototype().value());
  }
  std(t1, oopDesc::mark_offset_in_bytes(), obj);
  store_klass(obj, klass);
  if (len->is_valid()) {
    stw(len, arrayOopDesc::length_offset_in_bytes(), obj);
  } else if (UseCompressedClassPointers) {
    // Otherwise length is in the class gap.
    store_klass_gap(obj);
  }
}


void C1_MacroAssembler::initialize_body(Register base, Register index) {
  assert_different_registers(base, index);
  srdi(index, index, LogBytesPerWord);
  clear_memory_doubleword(base, index);
}

void C1_MacroAssembler::initialize_body(Register obj, Register tmp1, Register tmp2,
                                        int obj_size_in_bytes, int hdr_size_in_bytes) {
  const int index = (obj_size_in_bytes - hdr_size_in_bytes) / HeapWordSize;

  // 2x unrolled loop is shorter with more than 9 HeapWords.
  if (index <= 9) {
    clear_memory_unrolled(obj, index, R0, hdr_size_in_bytes);
  } else {
    const Register base_ptr = tmp1,
                   cnt_dwords = tmp2;

    addi(base_ptr, obj, hdr_size_in_bytes); // Compute address of first element.
    clear_memory_doubleword(base_ptr, cnt_dwords, R0, index);
  }
}

void C1_MacroAssembler::allocate_object(
  Register obj,                        // result: pointer to object after successful allocation
  Register t1,                         // temp register
  Register t2,                         // temp register
  Register t3,                         // temp register
  int      hdr_size,                   // object header size in words
  int      obj_size,                   // object size in words
  Register klass,                      // object klass
  Label&   slow_case                   // continuation point if fast allocation fails
) {
  assert_different_registers(obj, t1, t2, t3, klass);

  // allocate space & initialize header
  if (!is_simm16(obj_size * wordSize)) {
    // Would need to use extra register to load
    // object size => go the slow case for now.
    b(slow_case);
    return;
  }
  try_allocate(obj, noreg, obj_size * wordSize, t2, t3, slow_case);

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

void C1_MacroAssembler::initialize_object(
  Register obj,                        // result: pointer to object after successful allocation
  Register klass,                      // object klass
  Register var_size_in_bytes,          // object size in bytes if unknown at compile time; invalid otherwise
  int      con_size_in_bytes,          // object size in bytes if   known at compile time
  Register t1,                         // temp register
  Register t2                          // temp register
  ) {
  const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;

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

#ifdef ASSERT
  {
    lwz(t1, in_bytes(Klass::layout_helper_offset()), klass);
    if (var_size_in_bytes != noreg) {
      cmpw(CCR0, t1, var_size_in_bytes);
    } else {
      cmpwi(CCR0, t1, con_size_in_bytes);
    }
    asm_assert_eq("bad size in initialize_object", 0x753);
  }
#endif

  // Initialize body.
  if (var_size_in_bytes != noreg) {
    // Use a loop.
    addi(t1, obj, hdr_size_in_bytes);                // Compute address of first element.
    addi(t2, var_size_in_bytes, -hdr_size_in_bytes); // Compute size of body.
    initialize_body(t1, t2);
  } else if (con_size_in_bytes > hdr_size_in_bytes) {
    // Use a loop.
    initialize_body(obj, t1, t2, con_size_in_bytes, hdr_size_in_bytes);
  }

  if (CURRENT_ENV->dtrace_alloc_probes()) {
    Unimplemented();
//    assert(obj == O0, "must be");
//    call(CAST_FROM_FN_PTR(address, Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)),
//         relocInfo::runtime_call_type);
  }

  verify_oop(obj);
}


void C1_MacroAssembler::allocate_array(
  Register obj,                        // result: pointer to array after successful allocation
  Register len,                        // array length
  Register t1,                         // temp register
  Register t2,                         // temp register
  Register t3,                         // temp register
  int      hdr_size,                   // object header size in words
  int      elt_size,                   // element size in bytes
  Register klass,                      // object klass
  Label&   slow_case                   // continuation point if fast allocation fails
) {
  assert_different_registers(obj, len, t1, t2, t3, klass);

  // Determine alignment mask.
  assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
  int log2_elt_size = exact_log2(elt_size);

  // Check for negative or excessive length.
  size_t max_length = max_array_allocation_length >> log2_elt_size;
  if (UseTLAB) {
    size_t max_tlab = align_up(ThreadLocalAllocBuffer::max_size() >> log2_elt_size, 64*K);
    if (max_tlab < max_length) { max_length = max_tlab; }
  }
  load_const_optimized(t1, max_length);
  cmpld(CCR0, len, t1);
  bc_far_optimized(Assembler::bcondCRbiIs1, bi0(CCR0, Assembler::greater), slow_case);

  // compute array size
  // note: If 0 <= len <= max_length, len*elt_size + header + alignment is
  //       smaller or equal to the largest integer; also, since top is always
  //       aligned, we can do the alignment here instead of at the end address
  //       computation.
  const Register arr_size = t1;
  Register arr_len_in_bytes = len;
  if (elt_size != 1) {
    sldi(t1, len, log2_elt_size);
    arr_len_in_bytes = t1;
  }
  addi(arr_size, arr_len_in_bytes, hdr_size * wordSize + MinObjAlignmentInBytesMask); // Add space for header & alignment.
  clrrdi(arr_size, arr_size, LogMinObjAlignmentInBytes);                              // Align array size.

  // Allocate space & initialize header.
  if (UseTLAB) {
    tlab_allocate(obj, arr_size, 0, t2, slow_case);
  } else {
    eden_allocate(obj, arr_size, 0, t2, t3, slow_case);
  }
  initialize_header(obj, klass, len, t2, t3);

  // Initialize body.
  const Register base  = t2;
  const Register index = t3;
  addi(base, obj, hdr_size * wordSize);               // compute address of first element
  addi(index, arr_size, -(hdr_size * wordSize));      // compute index = number of bytes to clear
  initialize_body(base, index);

  if (CURRENT_ENV->dtrace_alloc_probes()) {
    Unimplemented();
    //assert(obj == O0, "must be");
    //call(CAST_FROM_FN_PTR(address, Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)),
    //     relocInfo::runtime_call_type);
  }

  verify_oop(obj);
}


#ifndef PRODUCT

void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
  verify_oop_addr((RegisterOrConstant)(stack_offset + STACK_BIAS), R1_SP, "broken oop in stack slot");
}

void C1_MacroAssembler::verify_not_null_oop(Register r) {
  Label not_null;
  cmpdi(CCR0, r, 0);
  bne(CCR0, not_null);
  stop("non-null oop required");
  bind(not_null);
  if (!VerifyOops) return;
  verify_oop(r);
}

#endif // PRODUCT

void C1_MacroAssembler::null_check(Register r, Label* Lnull) {
  if (TrapBasedNullChecks) { // SIGTRAP based
    trap_null_check(r);
  } else { // explicit
    //const address exception_entry = Runtime1::entry_for(Runtime1::throw_null_pointer_exception_id);
    assert(Lnull != NULL, "must have Label for explicit check");
    cmpdi(CCR0, r, 0);
    bc_far_optimized(Assembler::bcondCRbiIs1, bi0(CCR0, Assembler::equal), *Lnull);
  }
}

address C1_MacroAssembler::call_c_with_frame_resize(address dest, int frame_resize) {
  if (frame_resize) { resize_frame(-frame_resize, R0); }
#if defined(ABI_ELFv2)
  address return_pc = call_c(dest, relocInfo::runtime_call_type);
#else
  address return_pc = call_c(CAST_FROM_FN_PTR(FunctionDescriptor*, dest), relocInfo::runtime_call_type);
#endif
  if (frame_resize) { resize_frame(frame_resize, R0); }
  return return_pc;
}