/*

 * Copyright (c) 1999, 2018, 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_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/markOop.hpp"

#include "runtime/basicLock.hpp"

#include "runtime/biasedLocking.hpp"

#include "runtime/os.hpp"

#include "runtime/sharedRuntime.hpp"

#include "runtime/stubRoutines.hpp"

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 == rax, "hdr must be rax, for the cmpxchg instruction");

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

  Label done;

  int null_check_offset = -1;

  verify_oop(obj);

  // save object being locked into the BasicObjectLock

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

  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

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

  // and mark it as unlocked

  orptr(hdr, markOopDesc::unlocked_value);

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

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

  // 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

  if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg!

  cmpxchgptr(disp_hdr, Address(obj, hdr_offset));

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

  if (PrintBiasedLockingStatistics) {

    cond_inc32(Assembler::equal,

               ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr()));

  }

  jcc(Assembler::equal, 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) rsp <= hdr

  // 3) hdr <= rsp + page_size

  //

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

  //

  // (hdr - rsp) & (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

  subptr(hdr, rsp);

  andptr(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)

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

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

  jcc(Assembler::notZero, slow_case);

  // done

  bind(done);

  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(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction");

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

  Label done;

  if (UseBiasedLocking) {

    // load object

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

    biased_locking_exit(obj, hdr, done);

  }

  // load displaced header

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

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

  testptr(hdr, hdr);

  // if we had recursive locking, we are done

  jcc(Assembler::zero, done);

  if (!UseBiasedLocking) {

    // load object

    movptr(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 (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg!

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

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

  // we do unlocking via runtime call

  jcc(Assembler::notEqual, 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);

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

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

  } else {

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

    movptr(Address(obj, oopDesc::mark_offset_in_bytes ()), (int32_t)(intptr_t)markOopDesc::prototype());

  }

#ifdef _LP64

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

    movptr(t1, klass);

    encode_klass_not_null(t1);

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

  } else

#endif

  {

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

  }

  if (len->is_valid()) {

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

  }

#ifdef _LP64

  else if (UseCompressedClassPointers) {

    xorptr(t1, t1);

    store_klass_gap(obj, t1);

  }

#endif

}

// preserves obj, destroys len_in_bytes

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

  assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");

  Label done;

  // len_in_bytes is positive and ptr sized

  subptr(len_in_bytes, hdr_size_in_bytes);

  jcc(Assembler::zero, done);

  zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1);

  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(obj == rax, "obj must be in rax, for cmpxchg");

  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, UseTLAB);

}

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

  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);

  if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {

    // clear rest of allocated space

    const Register t1_zero = t1;

    const Register index = t2;

    const int threshold = 6 * 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_zero);

    } else if (con_size_in_bytes <= threshold) {

      // use explicit null stores

      // code size = 2 + 3*n bytes (n = number of fields to clear)

      xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)

      for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord)

        movptr(Address(obj, i), t1_zero);

    } else if (con_size_in_bytes > hdr_size_in_bytes) {

      // use loop to null out the fields

      // code size = 16 bytes for even n (n = number of fields to clear)

      // initialize last object field first if odd number of fields

      xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)

      movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3);

      // initialize last object field if constant size is odd

      if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0)

        movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero);

      // initialize remaining object fields: rdx is a multiple of 2

      { Label loop;

        bind(loop);

        movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)),

               t1_zero);

        NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)),

               t1_zero);)

        decrement(index);

        jcc(Assembler::notZero, loop);

      }

    }

  }

  if (CURRENT_ENV->dtrace_alloc_probes()) {

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

    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, Address::ScaleFactor f, Register klass, Label& slow_case) {

  assert(obj == rax, "obj must be in rax, for cmpxchg");

  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

  cmpptr(len, (int32_t)max_array_allocation_length);

  jcc(Assembler::above, slow_case);

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

  // align object end

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

  lea(arr_size, Address(arr_size, len, f));

  andptr(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);

  if (CURRENT_ENV->dtrace_alloc_probes()) {

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

    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");

  int start_offset = offset();

  if (UseCompressedClassPointers) {

    load_klass(rscratch1, receiver);

    cmpptr(rscratch1, iCache);

  } else {

    cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes()));

  }

  // if icache check fails, then jump to runtime routine

  // Note: RECEIVER must still contain the receiver!

  jump_cc(Assembler::notEqual,

          RuntimeAddress(SharedRuntime::get_ic_miss_stub()));

  const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9);

  assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry");

}

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

  assert(bang_size_in_bytes >= frame_size_in_bytes, "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(). This matches the

  // ordering of C2's stack overflow check / rsp decrement and allows

  // the SharedRuntime stack overflow handling to be consistent

  // between the two compilers.

  generate_stack_overflow_check(bang_size_in_bytes);

  push(rbp);

  if (PreserveFramePointer) {

    mov(rbp, rsp);

  }

#ifdef TIERED

  // c2 leaves fpu stack dirty. Clean it on entry

  if (UseSSE < 2 ) {

    empty_FPU_stack();

  }

#endif // TIERED

  decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0

}

void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) {

  increment(rsp, frame_size_in_bytes);  // Does not emit code for frame_size == 0

  pop(rbp);

}

void C1_MacroAssembler::verified_entry() {

  if (C1Breakpoint || VerifyFPU || !UseStackBanging) {

    // Verified Entry first instruction should be 5 bytes long for correct

    // patching by patch_verified_entry().

    //

    // C1Breakpoint and VerifyFPU have one byte first instruction.

    // Also first instruction will be one byte "push(rbp)" if stack banging

    // code is not generated (see build_frame() above).

    // For all these cases generate long instruction first.

    fat_nop();

  }

  if (C1Breakpoint)int3();

  // build frame

  verify_FPU(0, "method_entry");

}

#ifndef PRODUCT

void C1_MacroAssembler::verify_stack_oop(int stack_offset) {

  if (!VerifyOops) return;

  verify_oop_addr(Address(rsp, stack_offset));

}

void C1_MacroAssembler::verify_not_null_oop(Register r) {

  if (!VerifyOops) return;

  Label not_null;

  testptr(r, r);

  jcc(Assembler::notZero, not_null);

  stop("non-null oop required");

  bind(not_null);

  verify_oop(r);

}

void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) {

#ifdef ASSERT

  if (inv_rax) movptr(rax, 0xDEAD);

  if (inv_rbx) movptr(rbx, 0xDEAD);

  if (inv_rcx) movptr(rcx, 0xDEAD);

  if (inv_rdx) movptr(rdx, 0xDEAD);

  if (inv_rsi) movptr(rsi, 0xDEAD);

  if (inv_rdi) movptr(rdi, 0xDEAD);

#endif

}

#endif // ifndef PRODUCT