RFR: 8150044: Generate classlists at build-time

[Claes Redestad]

Hi,

an innocuous last minute change slipped in which actually broke 
cross-compilation support. Adding this puts things back in order:

diff -r c861a5be9c88 common/autoconf/buildjdk-spec.gmk.in
--- a/common/autoconf/buildjdk-spec.gmk.in    Thu May 05 22:39:14 2016 -0700
+++ b/common/autoconf/buildjdk-spec.gmk.in    Fri May 06 14:47:12 2016 +0200
@@ -46,6 +46,7 @@
  HOTSPOT_DIST := $(patsubst 
$(BUILD_OUTPUT)%,$(BUILDJDK_OUTPUTDIR)%,$(HOTSPOT_DIST))
  SUPPORT_OUTPUTDIR := $(patsubst 
$(BUILD_OUTPUT)%,$(BUILDJDK_OUTPUTDIR)%,$(SUPPORT_OUTPUTDIR))
  JDK_OUTPUTDIR := $(patsubst 
$(BUILD_OUTPUT)%,$(BUILDJDK_OUTPUTDIR)%,$(JDK_OUTPUTDIR))
+IMAGES_OUTPUTDIR := $(patsubst 
$(BUILD_OUTPUT)%,$(BUILDJDK_OUTPUTDIR)%,$(IMAGES_OUTPUTDIR))

  OPENJDK_BUILD_CPU_LEGACY := @OPENJDK_BUILD_CPU_LEGACY@
  OPENJDK_BUILD_CPU_LEGACY_LIB := @OPENJDK_BUILD_CPU_LEGACY_LIB@

Re-running and doing more extensive testing via RBT; arm64 builds have 
already completed so tentatively looks clear.

As there are follow-up work in jake lined up which depends on this we 
want to push this directly to jdk9/dev as soon as possible. I heard Alan 
already mentioned this and got no push back, so unless there are loud 
objections I'll go ahead and submit the jprt push job as soon as tests 
finish.

Thanks!

/Claes

On 2016-05-04 15:36, Claes Redestad wrote:
> Hi,
>
> please review this change to generate classlists at build-time
>
> bug: https://bugs.openjdk.java.net/browse/JDK-8150044
>
> webrevs:
> top: http://cr.openjdk.java.net/~redestad/8150044/top.01/
> jdk: http://cr.openjdk.java.net/~redestad/8150044/jdk.01/
> hotspot: http://cr.openjdk.java.net/~redestad/8150044/hotspot.01/
>
> The implementation generates an interim image consisting of a minimal
> set of modules, then use this to run a small generator program to
> load common utilities and facilities and dump the result of this to a
> classlist that is then bundled with the final images.
>
> The smaller number of classes on the default classlist (~1100 instead
> of ~2500) requires some adjustment to the metaspace defaults.
>
> This achieves the following:
>
> - Removes a manual, error-prone process to update the versioned
>   classlists
> - Ensures the classlists shipped with the JDK/JRE is up to date
>   with recent JDK changes, e.g., when moving classes from sun.* to
>   jdk.internal.*
> - Automatically picks up and incorporates the output of jlink plugins
>   such as GenerateJLIClassesPlugin into the classlist
> - Supports cross-compilation build targets, although it runs using a
>   build JDK that can run on the host platform to generate such
>   classlists (this isn't ideal, but no worse than the current
>   situation, where the versioned classlist for the host platform is
>   simply copied to the cross-compiled target)
>
> There are a few concerns/drawbacks:
>
> - It does add complexity to the build, and concern has been voiced that
>   this would adversely affect build times. However, I'm happy to say
>   that on my machine build times are roughly the same:
>
> Before:
> real    2m37.303s
> user    35m33.576s
> sys    3m46.476s
>
> After:
> real    2m36.168s
> user    35m31.232s
> sys    3m52.268s
>
> (real time varies ± 5s from build to build)
>
> - Startup on the specific applications we've used to generate the
>   classlists for previously suffer small regressions. These are
>   specifically rather dated AWT and Swing-based applications. OTOH,
>   startup characteristics generally improve on other applications
>   (minimal VM, jetty, etc...)
>
> Testing: JPRT -testset hotspot
>
> Thanks!
>
> /Claes