RFR: 8377554: Load card table base and other values via AOTRuntimeConstants in AOT code [v4]

[Vladimir Kozlov]

On Tue, 24 Feb 2026 16:41:44 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> This also needs fixing in premain.
>
> No, `movptr` loads from this address. It is not `lea` instruction.
> And `movq` simply moves value from register to register - it does not do anything in this case.

Note, movptr() is macro instruction which checks reachability (which is always false when we dump AOT code):


void MacroAssembler::movptr(Register dst, AddressLiteral src) {
  if (src.is_lval()) {
    mov_literal64(dst, (intptr_t)src.target(), src.rspec());
  } else {
    if (reachable(src)) {
      movq(dst, as_Address(src));
    } else {
      lea(dst, src);
      movq(dst, Address(dst, 0));
    }
  }
}


But if you want to optimize knowing that we dumping AOT code use this:


    __ lea(rscratch, ExternalAddress(AOTRuntimeConstants::card_table_address()));
    __ movq(rscratch, Address(rscratch, 0));

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PR Review Comment: https://git.openjdk.org/jdk/pull/29884#discussion_r2848419572