src/hotspot/cpu/riscv/nativeInst_riscv.cpp

/*
 * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2014, 2020, Red Hat Inc. All rights reserved.
 * Copyright (c) 2020, 2023, Huawei Technologies Co., Ltd. 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.hpp"
#include "code/compiledIC.hpp"
#include "memory/resourceArea.hpp"
#include "nativeInst_riscv.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/handles.hpp"
#include "runtime/orderAccess.hpp"
#include "runtime/safepoint.hpp"
#include "runtime/sharedRuntime.hpp"
#include "runtime/stubRoutines.hpp"
#include "utilities/ostream.hpp"
#ifdef COMPILER1
#include "c1/c1_Runtime1.hpp"
#endif

Register NativeInstruction::extract_rs1(address instr) {
  assert_cond(instr != nullptr);
  return as_Register(Assembler::extract(Assembler::ld_instr(instr), 19, 15));
}

Register NativeInstruction::extract_rs2(address instr) {
  assert_cond(instr != nullptr);
  return as_Register(Assembler::extract(Assembler::ld_instr(instr), 24, 20));
}

Register NativeInstruction::extract_rd(address instr) {
  assert_cond(instr != nullptr);
  return as_Register(Assembler::extract(Assembler::ld_instr(instr), 11, 7));
}

uint32_t NativeInstruction::extract_opcode(address instr) {
  assert_cond(instr != nullptr);
  return Assembler::extract(Assembler::ld_instr(instr), 6, 0);
}

uint32_t NativeInstruction::extract_funct3(address instr) {
  assert_cond(instr != nullptr);
  return Assembler::extract(Assembler::ld_instr(instr), 14, 12);
}

bool NativeInstruction::is_pc_relative_at(address instr) {
  // auipc + jalr
  // auipc + addi
  // auipc + load
  // auipc + fload_load
  return (is_auipc_at(instr)) &&
         (is_addi_at(instr + instruction_size) ||
          is_jalr_at(instr + instruction_size) ||
          is_load_at(instr + instruction_size) ||
          is_float_load_at(instr + instruction_size)) &&
         check_pc_relative_data_dependency(instr);
}

// ie:ld(Rd, Label)
bool NativeInstruction::is_load_pc_relative_at(address instr) {
  return is_auipc_at(instr) && // auipc
         is_ld_at(instr + instruction_size) && // ld
         check_load_pc_relative_data_dependency(instr);
}

bool NativeInstruction::is_movptr_at(address instr) {
  return is_lui_at(instr) && // Lui
         is_addi_at(instr + instruction_size) && // Addi
         is_slli_shift_at(instr + instruction_size * 2, 11) && // Slli Rd, Rs, 11
         is_addi_at(instr + instruction_size * 3) && // Addi
         is_slli_shift_at(instr + instruction_size * 4, 6) && // Slli Rd, Rs, 6
         (is_addi_at(instr + instruction_size * 5) ||
          is_jalr_at(instr + instruction_size * 5) ||
          is_load_at(instr + instruction_size * 5)) && // Addi/Jalr/Load
         check_movptr_data_dependency(instr);
}

bool NativeInstruction::is_li16u_at(address instr) {
  return is_lui_at(instr) && // lui
         is_srli_at(instr + instruction_size) && // srli
         check_li16u_data_dependency(instr);
}

bool NativeInstruction::is_li32_at(address instr) {
  return is_lui_at(instr) && // lui
         is_addiw_at(instr + instruction_size) && // addiw
         check_li32_data_dependency(instr);
}

bool NativeInstruction::is_li64_at(address instr) {
  return is_lui_at(instr) && // lui
         is_addi_at(instr + instruction_size) && // addi
         is_slli_shift_at(instr + instruction_size * 2, 12) &&  // Slli Rd, Rs, 12
         is_addi_at(instr + instruction_size * 3) && // addi
         is_slli_shift_at(instr + instruction_size * 4, 12) &&  // Slli Rd, Rs, 12
         is_addi_at(instr + instruction_size * 5) && // addi
         is_slli_shift_at(instr + instruction_size * 6, 8) &&   // Slli Rd, Rs, 8
         is_addi_at(instr + instruction_size * 7) && // addi
         check_li64_data_dependency(instr);
}

void NativeCall::verify() {
  assert(NativeCall::is_call_at((address)this), "unexpected code at call site");
}

address NativeCall::destination() const {
  address addr = (address)this;
  assert(NativeInstruction::is_jal_at(instruction_address()), "inst must be jal.");
  address destination = MacroAssembler::target_addr_for_insn(instruction_address());

  // Do we use a trampoline stub for this call?
  CodeBlob* cb = CodeCache::find_blob(addr);
  assert(cb && cb->is_nmethod(), "sanity");
  nmethod *nm = (nmethod *)cb;
  if (nm != nullptr && nm->stub_contains(destination) && is_NativeCallTrampolineStub_at(destination)) {
    // Yes we do, so get the destination from the trampoline stub.
    const address trampoline_stub_addr = destination;
    destination = nativeCallTrampolineStub_at(trampoline_stub_addr)->destination();
  }

  return destination;
}

// Similar to replace_mt_safe, but just changes the destination. The
// important thing is that free-running threads are able to execute this
// call instruction at all times.
//
// Used in the runtime linkage of calls; see class CompiledIC.
//
// Add parameter assert_lock to switch off assertion
// during code generation, where no patching lock is needed.
void NativeCall::set_destination_mt_safe(address dest, bool assert_lock) {
  assert(!assert_lock ||
         (Patching_lock->is_locked() || SafepointSynchronize::is_at_safepoint()) ||
         CompiledICLocker::is_safe(addr_at(0)),
         "concurrent code patching");

  ResourceMark rm;
  address addr_call = addr_at(0);
  assert(NativeCall::is_call_at(addr_call), "unexpected code at call site");

  // Patch the constant in the call's trampoline stub.
  address trampoline_stub_addr = get_trampoline();
  if (trampoline_stub_addr != nullptr) {
    assert (!is_NativeCallTrampolineStub_at(dest), "chained trampolines");
    nativeCallTrampolineStub_at(trampoline_stub_addr)->set_destination(dest);
  }

  // Patch the call.
  if (Assembler::reachable_from_branch_at(addr_call, dest)) {
    set_destination(dest);
  } else {
    assert (trampoline_stub_addr != nullptr, "we need a trampoline");
    set_destination(trampoline_stub_addr);
  }

  ICache::invalidate_range(addr_call, instruction_size);
}

address NativeCall::get_trampoline() {
  address call_addr = addr_at(0);

  CodeBlob *code = CodeCache::find_blob(call_addr);
  assert(code != nullptr, "Could not find the containing code blob");

  address jal_destination = MacroAssembler::pd_call_destination(call_addr);
  if (code != nullptr && code->contains(jal_destination) && is_NativeCallTrampolineStub_at(jal_destination)) {
    return jal_destination;
  }

  if (code != nullptr && code->is_nmethod()) {
    return trampoline_stub_Relocation::get_trampoline_for(call_addr, (nmethod*)code);
  }

  return nullptr;
}

// Inserts a native call instruction at a given pc
void NativeCall::insert(address code_pos, address entry) { Unimplemented(); }

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

void NativeMovConstReg::verify() {
  if (!(nativeInstruction_at(instruction_address())->is_movptr() ||
        is_auipc_at(instruction_address()))) {
    fatal("should be MOVPTR or AUIPC");
  }
}

intptr_t NativeMovConstReg::data() const {
  address addr = MacroAssembler::target_addr_for_insn(instruction_address());
  if (maybe_cpool_ref(instruction_address())) {
    return Bytes::get_native_u8(addr);
  } else {
    return (intptr_t)addr;
  }
}

void NativeMovConstReg::set_data(intptr_t x) {
  if (maybe_cpool_ref(instruction_address())) {
    address addr = MacroAssembler::target_addr_for_insn(instruction_address());
    Bytes::put_native_u8(addr, x);
  } else {
    // Store x into the instruction stream.
    MacroAssembler::pd_patch_instruction_size(instruction_address(), (address)x);
    ICache::invalidate_range(instruction_address(), movptr_instruction_size);
  }

  // Find and replace the oop/metadata corresponding to this
  // instruction in oops section.
  CodeBlob* cb = CodeCache::find_blob(instruction_address());
  nmethod* nm = cb->as_nmethod_or_null();
  if (nm != nullptr) {
    RelocIterator iter(nm, instruction_address(), next_instruction_address());
    while (iter.next()) {
      if (iter.type() == relocInfo::oop_type) {
        oop* oop_addr = iter.oop_reloc()->oop_addr();
        Bytes::put_native_u8((address)oop_addr, x);
        break;
      } else if (iter.type() == relocInfo::metadata_type) {
        Metadata** metadata_addr = iter.metadata_reloc()->metadata_addr();
        Bytes::put_native_u8((address)metadata_addr, x);
        break;
      }
    }
  }
}

void NativeMovConstReg::print() {
  tty->print_cr(PTR_FORMAT ": mov reg, " INTPTR_FORMAT,
                p2i(instruction_address()), data());
}

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

int NativeMovRegMem::offset() const  {
  Unimplemented();
  return 0;
}

void NativeMovRegMem::set_offset(int x) { Unimplemented(); }

void NativeMovRegMem::verify() {
  Unimplemented();
}

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

void NativeJump::verify() { }


void NativeJump::check_verified_entry_alignment(address entry, address verified_entry) {
  // Patching to not_entrant can happen while activations of the method are
  // in use. The patching in that instance must happen only when certain
  // alignment restrictions are true. These guarantees check those
  // conditions.

  // Must be 4 bytes aligned
  MacroAssembler::assert_alignment(verified_entry);
}


address NativeJump::jump_destination() const {
  address dest = MacroAssembler::target_addr_for_insn(instruction_address());

  // We use jump to self as the unresolved address which the inline
  // cache code (and relocs) know about
  // As a special case we also use sequence movptr(r,0), jalr(r,0)
  // i.e. jump to 0 when we need leave space for a wide immediate
  // load

  // return -1 if jump to self or to 0
  if ((dest == (address) this) || dest == 0) {
    dest = (address) -1;
  }

  return dest;
};

void NativeJump::set_jump_destination(address dest) {
  // We use jump to self as the unresolved address which the inline
  // cache code (and relocs) know about
  if (dest == (address) -1)
    dest = instruction_address();

  MacroAssembler::pd_patch_instruction(instruction_address(), dest);
  ICache::invalidate_range(instruction_address(), instruction_size);
}

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

address NativeGeneralJump::jump_destination() const {
  NativeMovConstReg* move = nativeMovConstReg_at(instruction_address());
  address dest = (address) move->data();

  // We use jump to self as the unresolved address which the inline
  // cache code (and relocs) know about
  // As a special case we also use jump to 0 when first generating
  // a general jump

  // return -1 if jump to self or to 0
  if ((dest == (address) this) || dest == 0) {
    dest = (address) -1;
  }

  return dest;
}

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

bool NativeInstruction::is_safepoint_poll() {
  return is_lwu_to_zr(address(this));
}

bool NativeInstruction::is_lwu_to_zr(address instr) {
  assert_cond(instr != nullptr);
  return (extract_opcode(instr) == 0b0000011 &&
          extract_funct3(instr) == 0b110 &&
          extract_rd(instr) == zr);         // zr
}

// A 16-bit instruction with all bits ones is permanently reserved as an illegal instruction.
bool NativeInstruction::is_sigill_not_entrant() {
  // jvmci
  return uint_at(0) == 0xffffffff;
}

void NativeIllegalInstruction::insert(address code_pos) {
  assert_cond(code_pos != nullptr);
  Assembler::sd_instr(code_pos, 0xffffffff);   // all bits ones is permanently reserved as an illegal instruction
}

bool NativeInstruction::is_stop() {
  return uint_at(0) == 0xc0101073; // an illegal instruction, 'csrrw x0, time, x0'
}

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

// MT-safe inserting of a jump over a jump or a nop (used by
// nmethod::make_not_entrant)

void NativeJump::patch_verified_entry(address entry, address verified_entry, address dest) {

  assert(dest == SharedRuntime::get_handle_wrong_method_stub(), "expected fixed destination of patch");

  assert(nativeInstruction_at(verified_entry)->is_jump_or_nop() ||
         nativeInstruction_at(verified_entry)->is_sigill_not_entrant(),
         "riscv cannot replace non-jump with jump");

  check_verified_entry_alignment(entry, verified_entry);

  // Patch this nmethod atomically.
  if (Assembler::reachable_from_branch_at(verified_entry, dest)) {
    ptrdiff_t offset = dest - verified_entry;
    guarantee(Assembler::is_simm21(offset) && ((offset % 2) == 0),
              "offset is too large to be patched in one jal instruction."); // 1M

    uint32_t insn = 0;
    address pInsn = (address)&insn;
    Assembler::patch(pInsn, 31, 31, (offset >> 20) & 0x1);
    Assembler::patch(pInsn, 30, 21, (offset >> 1) & 0x3ff);
    Assembler::patch(pInsn, 20, 20, (offset >> 11) & 0x1);
    Assembler::patch(pInsn, 19, 12, (offset >> 12) & 0xff);
    Assembler::patch(pInsn, 11, 7, 0); // zero, no link jump
    Assembler::patch(pInsn, 6, 0, 0b1101111); // j, (jal x0 offset)
    Assembler::sd_instr(verified_entry, insn);
  } else {
    // We use an illegal instruction for marking a method as
    // not_entrant.
    NativeIllegalInstruction::insert(verified_entry);
  }

  ICache::invalidate_range(verified_entry, instruction_size);
}

void NativeGeneralJump::insert_unconditional(address code_pos, address entry) {
  CodeBuffer cb(code_pos, instruction_size);
  MacroAssembler a(&cb);
  Assembler::IncompressibleRegion ir(&a);  // Fixed length: see NativeGeneralJump::get_instruction_size()

  int32_t offset = 0;
  a.movptr(t0, entry, offset); // lui, addi, slli, addi, slli
  a.jalr(x0, t0, offset); // jalr

  ICache::invalidate_range(code_pos, instruction_size);
}

// MT-safe patching of a long jump instruction.
void NativeGeneralJump::replace_mt_safe(address instr_addr, address code_buffer) {
  ShouldNotCallThis();
}


address NativeCallTrampolineStub::destination(nmethod *nm) const {
  return ptr_at(data_offset);
}

void NativeCallTrampolineStub::set_destination(address new_destination) {
  set_ptr_at(data_offset, new_destination);
  OrderAccess::release();
}

uint32_t NativeMembar::get_kind() {
  uint32_t insn = uint_at(0);

  uint32_t predecessor = Assembler::extract(insn, 27, 24);
  uint32_t successor = Assembler::extract(insn, 23, 20);

  return MacroAssembler::pred_succ_to_membar_mask(predecessor, successor);
}

void NativeMembar::set_kind(uint32_t order_kind) {
  uint32_t predecessor = 0;
  uint32_t successor = 0;

  MacroAssembler::membar_mask_to_pred_succ(order_kind, predecessor, successor);

  uint32_t insn = uint_at(0);
  address pInsn = (address) &insn;
  Assembler::patch(pInsn, 27, 24, predecessor);
  Assembler::patch(pInsn, 23, 20, successor);

  address membar = addr_at(0);
  Assembler::sd_instr(membar, insn);
}

void NativePostCallNop::make_deopt() {
  MacroAssembler::assert_alignment(addr_at(0));
  NativeDeoptInstruction::insert(addr_at(0));
}

int NativePostCallNop::displacement() const {
  // Discard the high 32 bits
  return (int)(intptr_t)MacroAssembler::get_target_of_li32(addr_at(4));
}

void NativePostCallNop::patch(jint diff) {
  assert(diff != 0, "must be");
  assert(is_lui_to_zr_at(addr_at(4)) && is_addiw_to_zr_at(addr_at(8)), "must be");

  MacroAssembler::patch_imm_in_li32(addr_at(4), diff);
}

void NativeDeoptInstruction::verify() {
}

// Inserts an undefined instruction at a given pc
void NativeDeoptInstruction::insert(address code_pos) {
  // 0xc0201073 encodes CSRRW x0, instret, x0
  uint32_t insn = 0xc0201073;
  uint32_t *pos = (uint32_t *) code_pos;
  *pos = insn;
  ICache::invalidate_range(code_pos, 4);
}