C++ should_not_reach_here函数代码示例

void RangeCheckStub::emit_code(LIR_Assembler* ce) {
  __ bind(_entry);

  if (_info->deoptimize_on_exception()) {
    address a = Runtime1::entry_for(Runtime1::predicate_failed_trap_id);
    __ call(a, relocInfo::runtime_call_type);
    __ delayed()->nop();
    ce->add_call_info_here(_info);
    ce->verify_oop_map(_info);
    debug_only(__ should_not_reach_here());
    return;
  }

  if (_index->is_register()) {
    __ mov(_index->as_register(), G4);
  } else {
    __ set(_index->as_jint(), G4);
  }
  if (_throw_index_out_of_bounds_exception) {
    __ call(Runtime1::entry_for(Runtime1::throw_index_exception_id), relocInfo::runtime_call_type);
  } else {
    __ call(Runtime1::entry_for(Runtime1::throw_range_check_failed_id), relocInfo::runtime_call_type);
  }
  __ delayed()->nop();
  ce->add_call_info_here(_info);
  ce->verify_oop_map(_info);
  debug_only(__ should_not_reach_here());
}

void RangeCheckStub::emit_code(LIR_Assembler* ce) {
  __ bind(_entry);
  if (_info->deoptimize_on_exception()) {
    address a = Runtime1::entry_for(Runtime1::predicate_failed_trap_id);
    __ call(RuntimeAddress(a));
    ce->add_call_info_here(_info);
    ce->verify_oop_map(_info);
    debug_only(__ should_not_reach_here());
    return;
  }

  // pass the array index on stack because all registers must be preserved
  if (_index->is_cpu_register()) {
    ce->store_parameter(_index->as_register(), 0);
  } else {
    ce->store_parameter(_index->as_jint(), 0);
  }
  Runtime1::StubID stub_id;
  if (_throw_index_out_of_bounds_exception) {
    stub_id = Runtime1::throw_index_exception_id;
  } else {
    stub_id = Runtime1::throw_range_check_failed_id;
  }
  __ call(RuntimeAddress(Runtime1::entry_for(stub_id)));
  ce->add_call_info_here(_info);
  ce->verify_oop_map(_info);
  debug_only(__ should_not_reach_here());
}

void RangeCheckStub::emit_code(LIR_Assembler* ce) {
  __ bind(_entry);
  if (_info->deoptimize_on_exception()) {
    address a = Runtime1::entry_for (Runtime1::predicate_failed_trap_id);
    ce->emit_call_c(a);
    CHECK_BAILOUT();
    ce->add_call_info_here(_info);
    ce->verify_oop_map(_info);
    debug_only(__ should_not_reach_here());
    return;
  }

  // Pass the array index in Z_R1_scratch which is not managed by linear scan.
  if (_index->is_cpu_register()) {
    __ lgr_if_needed(Z_R1_scratch, _index->as_register());
  } else {
    __ load_const_optimized(Z_R1_scratch, _index->as_jint());
  }

  Runtime1::StubID stub_id;
  if (_throw_index_out_of_bounds_exception) {
    stub_id = Runtime1::throw_index_exception_id;
  } else {
    stub_id = Runtime1::throw_range_check_failed_id;
  }
  ce->emit_call_c(Runtime1::entry_for (stub_id));
  CHECK_BAILOUT();
  ce->add_call_info_here(_info);
  ce->verify_oop_map(_info);
  debug_only(__ should_not_reach_here());
}

void RangeCheckStub::emit_code(LIR_Assembler* ce) {
  __ bind(_entry);
  if (_info->deoptimize_on_exception()) {
    address a = Runtime1::entry_for(Runtime1::predicate_failed_trap_id);
    __ far_call(RuntimeAddress(a));
    ce->add_call_info_here(_info);
    ce->verify_oop_map(_info);
    debug_only(__ should_not_reach_here());
    return;
  }

  if (_index->is_cpu_register()) {
    __ mov(rscratch1, _index->as_register());
  } else {
    __ mov(rscratch1, _index->as_jint());
  }
  Runtime1::StubID stub_id;
  if (_throw_index_out_of_bounds_exception) {
    stub_id = Runtime1::throw_index_exception_id;
  } else {
    stub_id = Runtime1::throw_range_check_failed_id;
  }
  __ far_call(RuntimeAddress(Runtime1::entry_for(stub_id)), NULL, rscratch2);
  ce->add_call_info_here(_info);
  ce->verify_oop_map(_info);
  debug_only(__ should_not_reach_here());
}

void DeoptimizeStub::emit_code(LIR_Assembler* ce) {
    __ bind(_entry);
    __ call(Runtime1::entry_for(Runtime1::deoptimize_id), relocInfo::runtime_call_type);
    __ delayed()->nop();
    ce->add_call_info_here(_info);
    DEBUG_ONLY(__ should_not_reach_here());
}

void DeoptimizeStub::emit_code(LIR_Assembler* ce) {
  __ bind(_entry);
  __ call(SharedRuntime::deopt_blob()->unpack_with_reexecution());
  __ delayed()->nop();
  ce->add_call_info_here(_info);
  debug_only(__ should_not_reach_here());
}

void ArrayStoreExceptionStub::emit_code(LIR_Assembler* ce) {
  __ bind(_entry);
  __ call(Runtime1::entry_for(Runtime1::throw_array_store_exception_id), relocInfo::runtime_call_type);
  __ delayed()->nop();
  ce->add_call_info_here(_info);
  ce->verify_oop_map(_info);
#ifdef ASSERT
  __ should_not_reach_here();
#endif
}

// Abstract method entry
// Attempt to execute abstract method. Throw exception
//
address InterpreterGenerator::generate_abstract_entry(void) {
  address entry = __ pc();
  // abstract method entry
  // throw exception
  __ call_VM(noreg, CAST_FROM_FN_PTR(address, InterpreterRuntime::throw_AbstractMethodError));
  // the call_VM checks for exception, so we should never return here.
  __ should_not_reach_here();
  return entry;

}

void ImplicitNullCheckStub::emit_code(LIR_Assembler* ce) {
  ce->compilation()->implicit_exception_table()->append(_offset, __ offset());
  __ bind(_entry);
  __ call(Runtime1::entry_for(Runtime1::throw_null_pointer_exception_id),
          relocInfo::runtime_call_type);
  __ delayed()->nop();
  ce->add_call_info_here(_info);
  ce->verify_oop_map(_info);
#ifdef ASSERT
  __ should_not_reach_here();
#endif
}

void DivByZeroStub::emit_code(LIR_Assembler* ce) {
  if (_offset != -1) {
    ce->compilation()->implicit_exception_table()->append(_offset, __ offset());
  }
  __ bind(_entry);
  __ far_call(Address(Runtime1::entry_for(Runtime1::throw_div0_exception_id), relocInfo::runtime_call_type));
  ce->add_call_info_here(_info);
  ce->verify_oop_map(_info);
#ifdef ASSERT
  __ should_not_reach_here();
#endif
}

void SimpleExceptionStub::emit_code(LIR_Assembler* ce) {
  assert(__ rsp_offset() == 0, "frame size should be fixed");

  __ bind(_entry);
  // pass the object in a scratch register because all other registers
  // must be preserved
  if (_obj->is_cpu_register()) {
    __ mov(rscratch1, _obj->as_register());
  }
  __ far_call(RuntimeAddress(Runtime1::entry_for(_stub)), NULL, rscratch2);
  ce->add_call_info_here(_info);
  debug_only(__ should_not_reach_here());
}

OopMapSet* Runtime1::generate_exception_throw(StubAssembler* sasm, address target, bool has_argument) {
  // make a frame and preserve the caller's caller-save registers
  OopMap* oop_map = save_live_registers(sasm);
  int call_offset;
  if (!has_argument) {
    call_offset = __ call_RT(noreg, noreg, target);
  } else {
    call_offset = __ call_RT(noreg, noreg, target, G4);
  }
  OopMapSet* oop_maps = new OopMapSet();
  oop_maps->add_gc_map(call_offset, oop_map);

  __ should_not_reach_here();
  return oop_maps;
}

void ImplicitNullCheckStub::emit_code(LIR_Assembler* ce) {
  address a;
  if (_info->deoptimize_on_exception()) {
    // Deoptimize, do not throw the exception, because it is probably wrong to do it here.
    a = Runtime1::entry_for(Runtime1::predicate_failed_trap_id);
  } else {
    a = Runtime1::entry_for(Runtime1::throw_null_pointer_exception_id);
  }

  ce->compilation()->implicit_exception_table()->append(_offset, __ offset());
  __ bind(_entry);
  __ call(RuntimeAddress(a));
  ce->add_call_info_here(_info);
  ce->verify_oop_map(_info);
  debug_only(__ should_not_reach_here());
}

// Abstract method entry
// Attempt to execute abstract method. Throw exception
address InterpreterGenerator::generate_abstract_entry(void) {
  // rmethod: Method*
  // r13: sender SP

  address entry_point = __ pc();

  // abstract method entry

  //  pop return address, reset last_sp to NULL
  __ empty_expression_stack();
  __ restore_bcp();      // bcp must be correct for exception handler   (was destroyed)
  __ restore_locals();   // make sure locals pointer is correct as well (was destroyed)

  // throw exception
  __ call_VM(noreg, CAST_FROM_FN_PTR(address,
                             InterpreterRuntime::throw_AbstractMethodError));
  // the call_VM checks for exception, so we should never return here.
  __ should_not_reach_here();

  return entry_point;
}

int StubAssembler::call_RT(Register oop_result1, Register metadata_result, address entry_point, int number_of_arguments) {
  // for sparc changing the number of arguments doesn't change
  // anything about the frame size so we'll always lie and claim that
  // we are only passing 1 argument.
  set_num_rt_args(1);

  assert_not_delayed();
  // bang stack before going to runtime
  set(-os::vm_page_size() + STACK_BIAS, G3_scratch);
  st(G0, SP, G3_scratch);

  // debugging support
  assert(number_of_arguments >= 0   , "cannot have negative number of arguments");

  set_last_Java_frame(SP, noreg);
  if (VerifyThread)  mov(G2_thread, O0); // about to be smashed; pass early
  save_thread(L7_thread_cache);
  // do the call
  call(entry_point, relocInfo::runtime_call_type);
  if (!VerifyThread) {
    delayed()->mov(G2_thread, O0);  // pass thread as first argument
  } else {
    delayed()->nop();             // (thread already passed)
  }
  int call_offset = offset();  // offset of return address
  restore_thread(L7_thread_cache);
  reset_last_Java_frame();

  // check for pending exceptions
  { Label L;
    Address exception_addr(G2_thread, Thread::pending_exception_offset());
    ld_ptr(exception_addr, Gtemp);
    br_null_short(Gtemp, pt, L);
    Address vm_result_addr(G2_thread, JavaThread::vm_result_offset());
    st_ptr(G0, vm_result_addr);
    Address vm_result_addr_2(G2_thread, JavaThread::vm_result_2_offset());
    st_ptr(G0, vm_result_addr_2);

    if (frame_size() == no_frame_size) {
      // we use O7 linkage so that forward_exception_entry has the issuing PC
      call(StubRoutines::forward_exception_entry(), relocInfo::runtime_call_type);
      delayed()->restore();
    } else if (_stub_id == Runtime1::forward_exception_id) {
      should_not_reach_here();
    } else {
      AddressLiteral exc(Runtime1::entry_for(Runtime1::forward_exception_id));
      jump_to(exc, G4);
      delayed()->nop();
    }
    bind(L);
  }

  // get oop result if there is one and reset the value in the thread
  if (oop_result1->is_valid()) {                    // get oop result if there is one and reset it in the thread
    get_vm_result  (oop_result1);
  } else {
    // be a little paranoid and clear the result
    Address vm_result_addr(G2_thread, JavaThread::vm_result_offset());
    st_ptr(G0, vm_result_addr);
  }

  // get second result if there is one and reset the value in the thread
  if (metadata_result->is_valid()) {
    get_vm_result_2  (metadata_result);
  } else {
    // be a little paranoid and clear the result
    Address vm_result_addr_2(G2_thread, JavaThread::vm_result_2_offset());
    st_ptr(G0, vm_result_addr_2);
  }

  return call_offset;
}