RFR: 8255301: Common and strengthen the code in ciMemberName and ciMethodHandle

[Vladimir Ivanov]

On Fri, 23 Oct 2020 08:40:55 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> src/hotspot/share/ci/ciMemberName.cpp line 46:
>> 
>>> 44:     return CURRENT_ENV->get_method((Method*) vmtarget);
>>> 45:   } else {
>>> 46:     fatal("vmtarget should be a method");
>> 
>> There's a slight difference in behavior here: `fatal()` is present in product binaries while `assert()` is not. 
>> Is the change deliberate?
>
> Yes. Because AFAICS, the `get_vmtarget` callers use the result without any null checks, calling member methods off that `ciMethod*`, and thus release bits would (hopefully) `SEGV` if this path is taken. In this case, it seems prudent to `fatal()` at sensible point before that happens.

Ok. I took a closer look and noticed that `java_lang_invoke_MemberName::vmtarget` already returns `Method*`. So, the code can be rewritten as follows:
  Method* vmtarget = java_lang_invoke_MemberName::vmtarget(get_oop());
  return CURRENT_ENV->get_method(vmtarget);

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PR: https://git.openjdk.java.net/jdk/pull/825