RFR: 8278638: Remove FLAG_IS_CMDLINE(UseSharedSpaces)

[Harold Seigel]

On Tue, 14 Dec 2021 16:06:28 GMT, Harold Seigel <hseigel at openjdk.org> wrote:

> Please review this small fix for bug JDK-827638.  The fix was tested by running Mach5 tiers 1 and 2 on Linux, Mac OS, and Windows, Mach5 tier 4 on Linux x64, and by building on linux-aarch64-zero and linux-x64-zero.
> 
> Thanks, Harold

If the user specified -Xshare:on then both UseSharedSpaces and RequireSharedSpaces would get set to TRUE (both before and after this change).  This would cause the JNI_ERR to be returned before the check if UseSharedSpaces was specified:


  if (DumpSharedSpaces || RequireSharedSpaces) {
    jio_fprintf(defaultStream::error_stream(),
      "Shared spaces are not supported in this VM\n");
    return JNI_ERR;
  }
           ...
  if ((UseSharedSpaces && FLAG_IS_CMDLINE(UseSharedSpaces)) ||
      log_is_enabled(Info, cds)) {
    warning("Shared spaces are not supported in this VM");
    FLAG_SET_DEFAULT(UseSharedSpaces, false);
    LogConfiguration::configure_stdout(LogLevel::Off, true, LOG_TAGS(cds));
  }
  no_shared_spaces("CDS Disabled");



So, I think that specifying -Xshare:auto is equivalent to the old -XX:+UseSharedSpace.

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PR: https://git.openjdk.java.net/jdk/pull/6835