RFR: compile-time guard some UseSharedSpaces-only coding with the INCLUDE_CDS macro - was :RE: jdk10 : UseSharedSpaces flag and INCLUDE_CDS macro

[Jiangli Zhou]

Hi Baesken,

Thank you for making the changes.

Related to the change in universe_init() (universe.cpp), the 'if (DumpSharedSpaces)’ block at line 715 is also CDS only. To be consistent, you might want to include it under #if INCLUDE_CDS as well.
--- 695,716 ----
    Universe::_loader_addClass_cache    = new LatestMethodCache();
    Universe::_pd_implies_cache         = new LatestMethodCache();
    Universe::_throw_illegal_access_error_cache = new LatestMethodCache();
    Universe::_do_stack_walk_cache = new LatestMethodCache();
  
+ #if INCLUDE_CDS
    if (UseSharedSpaces) {
      // Read the data structures supporting the shared spaces (shared
      // system dictionary, symbol table, etc.).  After that, access to
      // the file (other than the mapped regions) is no longer needed, and
      // the file is closed. Closing the file does not affect the
      // currently mapped regions.
      MetaspaceShared::initialize_shared_spaces();
      StringTable::create_table();
!   } else
! #endif
!   {
      SymbolTable::create_table();
      StringTable::create_table();
  
      if (DumpSharedSpaces) {
        MetaspaceShared::prepare_for_dumping();
In the past we have been trying to avoid adding too many #if in the code for better readability. For the CDS only code in universe.cpp (and a few other files), since the callee functions (e.g. initialize_shared_spaces()) are already defined with two versions (with and without INCLUDE_CDS). The builds without CDS also works fine even #if INCLUDE_CDS are not added.

Thanks,
Jiangli

> On Jul 13, 2017, at 5:18 AM, Baesken, Matthias <matthias.baesken at sap.com> wrote:
> 
>> Thank you for noticing that. Yes, it would be helpful if you can add the #if INCLUDE_CDS for CDS only code. 
>> I can help you integrate the changes after they are reviewed.
> 
> Thanks for your feedback !
> 
> I created a bug :
> 
> https://bugs.openjdk.java.net/browse/JDK-8184323
> 
> 
> and a webrev :
> 
> http://cr.openjdk.java.net/~mbaesken/webrevs/8184323/
> 
> 
> Best regards, Matthias
> 
> 
> -----Original Message-----
> From: Jiangli Zhou [mailto:jiangli.zhou at oracle.com] 
> Sent: Montag, 10. Juli 2017 17:54
> To: Baesken, Matthias <matthias.baesken at sap.com>
> Cc: hotspot-dev at openjdk.java.net; build-dev at openjdk.java.net
> Subject: Re: jdk10 : UseSharedSpaces flag and INCLUDE_CDS macro
> 
> Hi Matthias,
> 
> Thank you for noticing that. Yes, it would be helpful if you can add the #if INCLUDE_CDS for CDS only code. I can help you integrate the changes after they are reviewed.
> 
> Thanks!
> Jiangli
> 
>> On Jul 5, 2017, at 6:36 AM, Baesken, Matthias <matthias.baesken at sap.com> wrote:
>> 
>> Hello, when looking into CDS related build options,  I noticed  that most  code-parts  that are executed only when UseSharedSpaces is set,
>> are guarded by  the compile-time macro    INCLUDE_CDS   to support  switching off   compilation of this coding
>> when  CDS is disabled at compile time  :
>> 
>> 
>> See  hotspot/make/lib/JvmFeatures.gmk  :
>> 
>> ifneq ($(call check-jvm-feature, cds), true)
>> JVM_CFLAGS_FEATURES += -DINCLUDE_CDS=0
>> 
>> 
>> 
>> However some places miss the compile-time guarding ( #if INCLUDE_CDS  ....) for example in
>> 
>> 
>> share/vm/prims/jvmtiRedefineClasses.cpp
>> share/vm/memory/universe.cpp
>> 
>> (also some other places)
>> 
>> 
>> Should I prepare a change and add the compile-time guard at the places where missing as well ?
>> 
>> Best regards, Matthias
>