file: jdk/src/hotspot/share/interpreter/interpreterRuntime.cpp

function:

void InterpreterRuntime::resolve_get_put(JavaThread* thread, Bytecodes::Code bytecode) {
  Thread* THREAD = thread;
  // resolve field
  fieldDescriptor info;
  LastFrameAccessor last_frame(thread);
  constantPoolHandle pool(thread, last_frame.method()->constants());
  methodHandle m(thread, last_frame.method());
  bool is_put    = (bytecode == Bytecodes::_putfield  || bytecode == Bytecodes::_nofast_putfield ||
                    bytecode == Bytecodes::_putstatic);
  bool is_static = (bytecode == Bytecodes::_getstatic || bytecode == Bytecodes::_putstatic);

  {
    JvmtiHideSingleStepping jhss(thread);
    LinkResolver::resolve_field_access(info, pool, last_frame.get_index_u2_cpcache(bytecode),
                                       m, bytecode, CHECK);
  } // end JvmtiHideSingleStepping

  // check if link resolution caused cpCache to be updated
  ConstantPoolCacheEntry* cp_cache_entry = last_frame.cache_entry();
  if (cp_cache_entry->is_resolved(bytecode)) return;

  // compute auxiliary field attributes
  TosState state  = as_TosState(info.field_type());

  // Resolution of put instructions on final fields is delayed. That is required so that
  // exceptions are thrown at the correct place (when the instruction is actually invoked).
  // If we do not resolve an instruction in the current pass, leaving the put_code
  // set to zero will cause the next put instruction to the same field to reresolve.

  // Resolution of put instructions to final instance fields with invalid updates (i.e.,
  // to final instance fields with updates originating from a method different than <init>)
  // is inhibited. A putfield instruction targeting an instance final field must throw
  // an IllegalAccessError if the instruction is not in an instance
  // initializer method <init>. If resolution were not inhibited, a putfield
  // in an initializer method could be resolved in the initializer. Subsequent
  // putfield instructions to the same field would then use cached information.
  // As a result, those instructions would not pass through the VM. That is,
  // checks in resolve_field_access() would not be executed for those instructions
  // and the required IllegalAccessError would not be thrown.
  //
  // Also, we need to delay resolving getstatic and putstatic instructions until the
  // class is initialized.  This is required so that access to the static
  // field will call the initialization function every time until the class
  // is completely initialized ala. in 2.17.5 in JVM Specification.
  InstanceKlass* klass = info.field_holder();
  bool uninitialized_static = is_static && !klass->is_initialized();
  bool has_initialized_final_update = info.field_holder()->major_version() >= 53 &&
                                      info.has_initialized_final_update();
  assert(!(has_initialized_final_update && !info.access_flags().is_final()), "Fields with initialized final updates must be final");

  Bytecodes::Code get_code = (Bytecodes::Code)0;
  Bytecodes::Code put_code = (Bytecodes::Code)0;
  if (!uninitialized_static) {
    get_code = ((is_static) ? Bytecodes::_getstatic : Bytecodes::_getfield);
    if ((is_put && !has_initialized_final_update) || !info.access_flags().is_final()) {
      put_code = ((is_static) ? Bytecodes::_putstatic : Bytecodes::_putfield);
    }
  }

  cp_cache_entry->set_field(
    get_code,
    put_code,
    info.field_holder(),
    info.index(),
    info.offset(),
    state,
    info.access_flags().is_final(),
    info.access_flags().is_volatile(),

pool->pool_holder()
  );
}

【 在 xeagle 的大作中提到: 】
: 我现在就是不理解 jvm 的解释执行到底是怎么做的, 是否要先把执行的片段翻译成机器指令再执行, 还是一个一个的字节码逐个解释. 有没有相关的文章可以参考一下吗
:
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FROM 123.115.68.*