C++ NativeJump类代码示例

void CodeInstaller::pd_relocate_ForeignCall(NativeInstruction* inst, jlong foreign_call_destination, TRAPS) {
  address pc = (address) inst;
  if (inst->is_call()) {
    // NOTE: for call without a mov, the offset must fit a 32-bit immediate
    //       see also CompilerToVM.getMaxCallTargetOffset()
    NativeCall* call = nativeCall_at(pc);
    call->set_destination((address) foreign_call_destination);
    _instructions->relocate(call->instruction_address(), runtime_call_Relocation::spec(), Assembler::call32_operand);
  } else if (inst->is_mov_literal64()) {
    NativeMovConstReg* mov = nativeMovConstReg_at(pc);
    mov->set_data((intptr_t) foreign_call_destination);
    _instructions->relocate(mov->instruction_address(), runtime_call_Relocation::spec(), Assembler::imm_operand);
  } else if (inst->is_jump()) {
    NativeJump* jump = nativeJump_at(pc);
    jump->set_jump_destination((address) foreign_call_destination);
    _instructions->relocate(jump->instruction_address(), runtime_call_Relocation::spec(), Assembler::call32_operand);
  } else if (inst->is_cond_jump()) {
    address old_dest = nativeGeneralJump_at(pc)->jump_destination();
    address disp = Assembler::locate_operand(pc, Assembler::call32_operand);
    *(jint*) disp += ((address) foreign_call_destination) - old_dest;
    _instructions->relocate(pc, runtime_call_Relocation::spec(), Assembler::call32_operand);
  } else {
    JVMCI_ERROR("unsupported relocation for foreign call");
  }

  TRACE_jvmci_3("relocating (foreign call)  at " PTR_FORMAT, p2i(inst));
}

void CompiledStaticCall::set_to_interpreted(methodHandle callee, address entry) {
  address stub = find_stub();
  guarantee(stub != NULL, "stub not found");

  if (TraceICs) {
    ResourceMark rm;
    tty->print_cr("[email protected]" INTPTR_FORMAT ": set_to_interpreted %s",
                  p2i(instruction_address()),
                  callee->name_and_sig_as_C_string());
  }

  // Creation also verifies the object.
  NativeMovConstReg* method_holder = nativeMovConstReg_at(stub);
  NativeJump*        jump          = nativeJump_at(method_holder->next_instruction_address());

#ifdef ASSERT
  // read the value once
  intptr_t data = method_holder->data();
  address destination = jump->jump_destination();
  assert(data == 0 || data == (intptr_t)callee(),
         "a) MT-unsafe modification of inline cache");
  assert(destination == (address)-1 || destination == entry,
         "b) MT-unsafe modification of inline cache");
#endif

  // Update stub.
  method_holder->set_data((intptr_t)callee());
  jump->set_jump_destination(entry);

  // Update jump to call.
  set_destination_mt_safe(stub);
}

void CompiledStaticCall::set_stub_to_clean(static_stub_Relocation* static_stub) {
  assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "mt unsafe call");
  // Reset stub
  address stub = static_stub->addr();
  assert(stub!=NULL, "stub not found");
  NativeMovConstReg* method_holder = nativeMovConstReg_at(stub);   // creation also verifies the object
  NativeJump*        jump          = nativeJump_at(method_holder->next_instruction_address());
  method_holder->set_data(0);
  jump->set_jump_destination((address)-1);
}

void CodeInstaller::pd_relocate_ForeignCall(NativeInstruction* inst, jlong foreign_call_destination, TRAPS) {
  address pc = (address) inst;
  if (inst->is_call()) {
    NativeCall* call = nativeCall_at(pc);
    call->set_destination((address) foreign_call_destination);
    _instructions->relocate(call->instruction_address(), runtime_call_Relocation::spec());
  } else if (inst->is_sethi()) {
    NativeJump* jump = nativeJump_at(pc);
    jump->set_jump_destination((address) foreign_call_destination);
    _instructions->relocate(jump->instruction_address(), runtime_call_Relocation::spec());
  } else {
    JVMCI_ERROR("unknown call or jump instruction at " PTR_FORMAT, p2i(pc));
  }
  TRACE_jvmci_3("relocating (foreign call) at " PTR_FORMAT, p2i(inst));
}

// Code for unit testing implementation of NativeJump class
void NativeJump::test() {
#ifdef ASSERT
  ResourceMark rm;
  CodeBuffer cb("test", 100, 100);
  MacroAssembler* a = new MacroAssembler(&cb);
  NativeJump* nj;
  uint idx;
  int offsets[] = {
    0x0,
    0xffffffff,
    0x7fffffff,
    0x80000000,
    4096,
    4097,
    0x20,
    0x4000,
  };

  VM_Version::allow_all();

  AddressLiteral al(0x7fffbbbb, relocInfo::external_word_type);
  a->sethi(al, I3);
  a->jmpl(I3, al.low10(), G0, RelocationHolder::none);
  a->delayed()->nop();
  a->sethi(al, I3);
  a->jmpl(I3, al.low10(), L3, RelocationHolder::none);
  a->delayed()->nop();

  nj = nativeJump_at( cb.insts_begin() );
  nj->print();

  nj = nativeJump_at( nj->next_instruction_address() );
  for (idx = 0; idx < ARRAY_SIZE(offsets); idx++) {
    nj->set_jump_destination( nj->instruction_address() + offsets[idx] );
    assert(nj->jump_destination() == (nj->instruction_address() + offsets[idx]), "check unit test");
    nj->print();
  }

  VM_Version::revert();
#endif // ASSERT
}

address InlineCacheBuffer::ic_buffer_entry_point(address code_begin) {
  NativeMovConstReg* move = nativeMovConstReg_at(code_begin);   // creation also verifies the object
  NativeJump*        jump = nativeJump_at(move->next_instruction_address());
  return jump->jump_destination();
}

address InlineCacheBuffer::ic_buffer_entry_point(address code_begin) {
  address jump_address;
  jump_address = code_begin + NativeInstruction::instruction_size;
  NativeJump* jump = nativeJump_at(jump_address);
  return jump->jump_destination();
}