/*

 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.

 * Copyright (c) 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 "registerSaver_s390.hpp"

#include "gc/g1/g1CardTable.hpp"

#include "gc/g1/g1BarrierSet.hpp"

#include "gc/g1/g1BarrierSetAssembler.hpp"

#include "gc/g1/g1ThreadLocalData.hpp"

#include "gc/g1/heapRegion.hpp"

#include "interpreter/interp_masm.hpp"

#include "runtime/sharedRuntime.hpp"

#define __ masm->

#define BLOCK_COMMENT(str) if (PrintAssembly) __ block_comment(str)

void G1BarrierSetAssembler::gen_write_ref_array_pre_barrier(MacroAssembler* masm, DecoratorSet decorators,

                                                            Register addr, Register count) {

  bool dest_uninitialized = (decorators & AS_DEST_NOT_INITIALIZED) != 0;

  // With G1, don't generate the call if we statically know that the target is uninitialized.

  if (!dest_uninitialized) {

    // Is marking active?

    Label filtered;

    assert_different_registers(addr,  Z_R0_scratch);  // would be destroyed by push_frame()

    assert_different_registers(count, Z_R0_scratch);  // would be destroyed by push_frame()

    Register Rtmp1 = Z_R0_scratch;

    const int active_offset = in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset());

    if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {

      __ load_and_test_int(Rtmp1, Address(Z_thread, active_offset));

    } else {

      guarantee(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");

      __ load_and_test_byte(Rtmp1, Address(Z_thread, active_offset));

    }

    __ z_bre(filtered); // Activity indicator is zero, so there is no marking going on currently.

    RegisterSaver::save_live_registers(masm, RegisterSaver::arg_registers); // Creates frame.

    if (UseCompressedOops) {

      __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSet::write_ref_array_pre_narrow_oop_entry), addr, count);

    } else {

      __ call_VM_leaf(CAST_FROM_FN_PTR(address, G1BarrierSet::write_ref_array_pre_oop_entry), addr, count);

    }

    RegisterSaver::restore_live_registers(masm, RegisterSaver::arg_registers);

    __ bind(filtered);

  }

}

void G1BarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,

                                                             Register addr, Register count, bool do_return) {

  address entry_point = CAST_FROM_FN_PTR(address, G1BarrierSet::write_ref_array_post_entry);

  if (!do_return) {

    assert_different_registers(addr,  Z_R0_scratch);  // would be destroyed by push_frame()

    assert_different_registers(count, Z_R0_scratch);  // would be destroyed by push_frame()

    RegisterSaver::save_live_registers(masm, RegisterSaver::arg_registers); // Creates frame.

    __ call_VM_leaf(entry_point, addr, count);

    RegisterSaver::restore_live_registers(masm, RegisterSaver::arg_registers);

  } else {

    // Tail call: call c and return to stub caller.

    __ lgr_if_needed(Z_ARG1, addr);

    __ lgr_if_needed(Z_ARG2, count);

    __ load_const(Z_R1, entry_point);

    __ z_br(Z_R1); // Branch without linking, callee will return to stub caller.

  }

}

void G1BarrierSetAssembler::load_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,

                                    const Address& src, Register dst, Register tmp1, Register tmp2, Label *is_null) {

  bool on_oop = type == T_OBJECT || type == T_ARRAY;

  bool on_weak = (decorators & ON_WEAK_OOP_REF) != 0;

  bool on_phantom = (decorators & ON_PHANTOM_OOP_REF) != 0;

  bool on_reference = on_weak || on_phantom;

  Label done;

  if (on_oop && on_reference && is_null == NULL) { is_null = &done; }

  ModRefBarrierSetAssembler::load_at(masm, decorators, type, src, dst, tmp1, tmp2, is_null);

  if (on_oop && on_reference) {

    // Generate the G1 pre-barrier code to log the value of

    // the referent field in an SATB buffer.

    g1_write_barrier_pre(masm, decorators | OOP_NOT_NULL,

                         NULL /* obj */,

                         dst  /* pre_val */,

                         noreg/* preserve */ ,

                         tmp1, tmp2 /* tmp */,

                         true /* pre_val_needed */);

  }

  __ bind(done);

}

void G1BarrierSetAssembler::g1_write_barrier_pre(MacroAssembler* masm, DecoratorSet decorators,

                                                 const Address*  obj,

                                                 Register        Rpre_val,      // Ideally, this is a non-volatile register.

                                                 Register        Rval,          // Will be preserved.

                                                 Register        Rtmp1,         // If Rpre_val is volatile, either Rtmp1

                                                 Register        Rtmp2,         // or Rtmp2 has to be non-volatile.

                                                 bool            pre_val_needed // Save Rpre_val across runtime call, caller uses it.

                                                 ) {

  bool not_null  = (decorators & OOP_NOT_NULL) != 0,

       preloaded = obj == NULL;

  const Register Robj = obj ? obj->base() : noreg,

                 Roff = obj ? obj->index() : noreg;

  const int active_offset = in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset());

  const int buffer_offset = in_bytes(G1ThreadLocalData::satb_mark_queue_buffer_offset());

  const int index_offset  = in_bytes(G1ThreadLocalData::satb_mark_queue_index_offset());

  assert_different_registers(Rtmp1, Rtmp2, Z_R0_scratch); // None of the Rtmp<i> must be Z_R0!!

  assert_different_registers(Robj, Z_R0_scratch);         // Used for addressing. Furthermore, push_frame destroys Z_R0!!

  assert_different_registers(Rval, Z_R0_scratch);         // push_frame destroys Z_R0!!

  Label callRuntime, filtered;

  BLOCK_COMMENT("g1_write_barrier_pre {");

  // Is marking active?

  // Note: value is loaded for test purposes only. No further use here.

  if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {

    __ load_and_test_int(Rtmp1, Address(Z_thread, active_offset));

  } else {

    guarantee(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");

    __ load_and_test_byte(Rtmp1, Address(Z_thread, active_offset));

  }

  __ z_bre(filtered); // Activity indicator is zero, so there is no marking going on currently.

  assert(Rpre_val != noreg, "must have a real register");

  // If an object is given, we need to load the previous value into Rpre_val.

  if (obj) {

    // Load the previous value...

    if (UseCompressedOops) {

      __ z_llgf(Rpre_val, *obj);

    } else {

      __ z_lg(Rpre_val, *obj);

    }

  }

  // Is the previous value NULL?

  // If so, we don't need to record it and we're done.

  // Note: pre_val is loaded, decompressed and stored (directly or via runtime call).

  //       Register contents is preserved across runtime call if caller requests to do so.

  if (preloaded && not_null) {

#ifdef ASSERT

    __ z_ltgr(Rpre_val, Rpre_val);

    __ asm_assert_ne("null oop not allowed (G1 pre)", 0x321); // Checked by caller.

#endif

  } else {

    __ z_ltgr(Rpre_val, Rpre_val);

    __ z_bre(filtered); // previous value is NULL, so we don't need to record it.

  }

  // Decode the oop now. We know it's not NULL.

  if (Robj != noreg && UseCompressedOops) {

    __ oop_decoder(Rpre_val, Rpre_val, /*maybeNULL=*/false);

  }

  // OK, it's not filtered, so we'll need to call enqueue.

  // We can store the original value in the thread's buffer

  // only if index > 0. Otherwise, we need runtime to handle.

  // (The index field is typed as size_t.)

  Register Rbuffer = Rtmp1, Rindex = Rtmp2;

  assert_different_registers(Rbuffer, Rindex, Rpre_val);

  __ z_lg(Rbuffer, buffer_offset, Z_thread);

  __ load_and_test_long(Rindex, Address(Z_thread, index_offset));

  __ z_bre(callRuntime); // If index == 0, goto runtime.

  __ add2reg(Rindex, -wordSize); // Decrement index.

  __ z_stg(Rindex, index_offset, Z_thread);

  // Record the previous value.

  __ z_stg(Rpre_val, 0, Rbuffer, Rindex);

  __ z_bru(filtered);  // We are done.

  Rbuffer = noreg;  // end of life

  Rindex  = noreg;  // end of life

  __ bind(callRuntime);

  // Save some registers (inputs and result) over runtime call

  // by spilling them into the top frame.

  if (Robj != noreg && Robj->is_volatile()) {

    __ z_stg(Robj, Robj->encoding()*BytesPerWord, Z_SP);

  }

  if (Roff != noreg && Roff->is_volatile()) {

    __ z_stg(Roff, Roff->encoding()*BytesPerWord, Z_SP);

  }

  if (Rval != noreg && Rval->is_volatile()) {

    __ z_stg(Rval, Rval->encoding()*BytesPerWord, Z_SP);

  }

  // Save Rpre_val (result) over runtime call.

  Register Rpre_save = Rpre_val;

  if ((Rpre_val == Z_R0_scratch) || (pre_val_needed && Rpre_val->is_volatile())) {

    guarantee(!Rtmp1->is_volatile() || !Rtmp2->is_volatile(), "oops!");

    Rpre_save = !Rtmp1->is_volatile() ? Rtmp1 : Rtmp2;

  }

  __ lgr_if_needed(Rpre_save, Rpre_val);

  // Push frame to protect top frame with return pc and spilled register values.

  __ save_return_pc();

  __ push_frame_abi160(0); // Will use Z_R0 as tmp.

  // Rpre_val may be destroyed by push_frame().

  __ call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_pre), Rpre_save, Z_thread);

  __ pop_frame();

  __ restore_return_pc();

  // Restore spilled values.

  if (Robj != noreg && Robj->is_volatile()) {

    __ z_lg(Robj, Robj->encoding()*BytesPerWord, Z_SP);

  }

  if (Roff != noreg && Roff->is_volatile()) {

    __ z_lg(Roff, Roff->encoding()*BytesPerWord, Z_SP);

  }

  if (Rval != noreg && Rval->is_volatile()) {

    __ z_lg(Rval, Rval->encoding()*BytesPerWord, Z_SP);

  }

  if (pre_val_needed && Rpre_val->is_volatile()) {

    __ lgr_if_needed(Rpre_val, Rpre_save);

  }

  __ bind(filtered);

  BLOCK_COMMENT("} g1_write_barrier_pre");

}

void G1BarrierSetAssembler::g1_write_barrier_post(MacroAssembler* masm, DecoratorSet decorators, Register Rstore_addr, Register Rnew_val,

                                                  Register Rtmp1, Register Rtmp2, Register Rtmp3) {

  bool not_null = (decorators & OOP_NOT_NULL) != 0;

  assert_different_registers(Rstore_addr, Rnew_val, Rtmp1, Rtmp2); // Most probably, Rnew_val == Rtmp3.

  Label callRuntime, filtered;

  CardTableBarrierSet* ct = barrier_set_cast<CardTableBarrierSet>(BarrierSet::barrier_set());

  assert(sizeof(*ct->card_table()->byte_map_base()) == sizeof(jbyte), "adjust this code");

  BLOCK_COMMENT("g1_write_barrier_post {");

  // Does store cross heap regions?

  // It does if the two addresses specify different grain addresses.

  if (G1RSBarrierRegionFilter) {

    if (VM_Version::has_DistinctOpnds()) {

      __ z_xgrk(Rtmp1, Rstore_addr, Rnew_val);

    } else {

      __ z_lgr(Rtmp1, Rstore_addr);

      __ z_xgr(Rtmp1, Rnew_val);

    }

    __ z_srag(Rtmp1, Rtmp1, HeapRegion::LogOfHRGrainBytes);

    __ z_bre(filtered);

  }

  // Crosses regions, storing NULL?

  if (not_null) {

#ifdef ASSERT

    __ z_ltgr(Rnew_val, Rnew_val);

    __ asm_assert_ne("null oop not allowed (G1 post)", 0x322); // Checked by caller.

#endif

  } else {

    __ z_ltgr(Rnew_val, Rnew_val);

    __ z_bre(filtered);

  }

  Rnew_val = noreg; // end of lifetime

  // Storing region crossing non-NULL, is card already dirty?

  assert(sizeof(*ct->card_table()->byte_map_base()) == sizeof(jbyte), "adjust this code");

  assert_different_registers(Rtmp1, Rtmp2, Rtmp3);

  // Make sure not to use Z_R0 for any of these registers.

  Register Rcard_addr = (Rtmp1 != Z_R0_scratch) ? Rtmp1 : Rtmp3;

  Register Rbase      = (Rtmp2 != Z_R0_scratch) ? Rtmp2 : Rtmp3;

  // calculate address of card

  __ load_const_optimized(Rbase, (address)ct->card_table()->byte_map_base());      // Card table base.

  __ z_srlg(Rcard_addr, Rstore_addr, CardTable::card_shift);         // Index into card table.

  __ z_algr(Rcard_addr, Rbase);                                      // Explicit calculation needed for cli.

  Rbase = noreg; // end of lifetime

  // Filter young.

  assert((unsigned int)G1CardTable::g1_young_card_val() <= 255, "otherwise check this code");

  __ z_cli(0, Rcard_addr, G1CardTable::g1_young_card_val());

  __ z_bre(filtered);

  // Check the card value. If dirty, we're done.

  // This also avoids false sharing of the (already dirty) card.

  __ z_sync(); // Required to support concurrent cleaning.

  assert((unsigned int)G1CardTable::dirty_card_val() <= 255, "otherwise check this code");

  __ z_cli(0, Rcard_addr, G1CardTable::dirty_card_val()); // Reload after membar.

  __ z_bre(filtered);

  // Storing a region crossing, non-NULL oop, card is clean.

  // Dirty card and log.

  __ z_mvi(0, Rcard_addr, G1CardTable::dirty_card_val());

  Register Rcard_addr_x = Rcard_addr;

  Register Rqueue_index = (Rtmp2 != Z_R0_scratch) ? Rtmp2 : Rtmp1;

  Register Rqueue_buf   = (Rtmp3 != Z_R0_scratch) ? Rtmp3 : Rtmp1;

  const int qidx_off    = in_bytes(G1ThreadLocalData::dirty_card_queue_index_offset());

  const int qbuf_off    = in_bytes(G1ThreadLocalData::dirty_card_queue_buffer_offset());

  if ((Rcard_addr == Rqueue_buf) || (Rcard_addr == Rqueue_index)) {

    Rcard_addr_x = Z_R0_scratch;  // Register shortage. We have to use Z_R0.

  }

  __ lgr_if_needed(Rcard_addr_x, Rcard_addr);

  __ load_and_test_long(Rqueue_index, Address(Z_thread, qidx_off));

  __ z_bre(callRuntime); // Index == 0 then jump to runtime.

  __ z_lg(Rqueue_buf, qbuf_off, Z_thread);

  __ add2reg(Rqueue_index, -wordSize); // Decrement index.

  __ z_stg(Rqueue_index, qidx_off, Z_thread);

  __ z_stg(Rcard_addr_x, 0, Rqueue_index, Rqueue_buf); // Store card.

  __ z_bru(filtered);

  __ bind(callRuntime);

  // TODO: do we need a frame? Introduced to be on the safe side.

  bool needs_frame = true;

  __ lgr_if_needed(Rcard_addr, Rcard_addr_x); // copy back asap. push_frame will destroy Z_R0_scratch!

  // VM call need frame to access(write) O register.

  if (needs_frame) {

    __ save_return_pc();

    __ push_frame_abi160(0); // Will use Z_R0 as tmp on old CPUs.

  }

  // Save the live input values.

  __ call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_post), Rcard_addr, Z_thread);

  if (needs_frame) {

    __ pop_frame();

    __ restore_return_pc();

  }

  __ bind(filtered);

  BLOCK_COMMENT("} g1_write_barrier_post");

}

void G1BarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,

                                         const Address& dst, Register val, Register tmp1, Register tmp2, Register tmp3) {

  bool on_array = (decorators & IN_HEAP_ARRAY) != 0;

  bool on_anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;

  bool precise = on_array || on_anonymous;

  // Load and record the previous value.

  g1_write_barrier_pre(masm, decorators, &dst, tmp3, val, tmp1, tmp2, false);

  BarrierSetAssembler::store_at(masm, decorators, type, dst, val, tmp1, tmp2, tmp3);

  // No need for post barrier if storing NULL

  if (val != noreg) {

    const Register base = dst.base(),

                   idx  = dst.index();

    const intptr_t disp = dst.disp();

    if (precise && (disp != 0 || idx != noreg)) {

      __ add2reg_with_index(base, disp, idx, base);

    }

    g1_write_barrier_post(masm, decorators, base, val, tmp1, tmp2, tmp3);

  }

}

void G1BarrierSetAssembler::resolve_jobject(MacroAssembler* masm, Register value, Register tmp1, Register tmp2) {

  NearLabel Ldone, Lnot_weak;

  __ z_ltgr(tmp1, value);

  __ z_bre(Ldone);          // Use NULL result as-is.

  __ z_nill(value, ~JNIHandles::weak_tag_mask);

  __ z_lg(value, 0, value); // Resolve (untagged) jobject.

  __ z_tmll(tmp1, JNIHandles::weak_tag_mask); // Test for jweak tag.

  __ z_braz(Lnot_weak);

  __ verify_oop(value);

  DecoratorSet decorators = IN_ROOT | ON_PHANTOM_OOP_REF;

  g1_write_barrier_pre(masm, decorators, (const Address*)NULL, value, noreg, tmp1, tmp2, true);

  __ bind(Lnot_weak);

  __ verify_oop(value);

  __ bind(Ldone);

}

#undef __