Preliminary request for review: 7025066 Build system changes to support SE Embedded integration

[Kelly O'Hair]

Just to clarify for people, BUILD_CLIENT_ONLY refers to building the client VM only.
Some of these variables should be documented in the top level README-builds.html file, but that
can be done under a separate CR if necessary.

The Library.gmk file seems like it is just a leftover debugging echo?

Looks like the Program.gmk file should be sharing the LD_RUNPATH_EXTRAS logic somehow, I originally
was trying to isolate all the $ORIGIN option setting to one place, oh well, not your issue. You have actually
cleanup some of these linker settings, so thanks for that.

The Release.gmk file needs  a major overhaul. :^(  I'm wondering if the various things being added here could
have their own separate functionality flags, rather than JAVASE_EMBEDDED,  have COMPRESS_JARS=true/false,
REDUCED_JRE=true/false, then have one place where JAVASE_EMBEDDED turns on what it wants?
Like the BUILD_CLIENT_ONLY setting. Just thoughts.
But I'm ok with what you have, just cringing a little whenever the file Release.gmk gets more added to it. :^(

In Defs-control.gmk you have a line with just "error ...some message" not exactly sure what you are expecting here.
You also use USE_ONLY_BOOTDIR_TOOLS?=true  and I have avoided ?=. The reason is that it assigns the
variable if it hasn't been defined, not if it was defined to be empty or expands to empty.
Between ?= and ifdef/ifndef, it gets pretty confusing what "defined" means, and I've been favoring using just
   ifeq ($(USE_ONLY_BOOTDIR_TOOLS),)
as the best way to ask if a variable will expand to nothing, which is usually the real question in most situations.
I have only used ifeq($(origin X),defined) when a variable being explicitly defined to an empty value needed to be
allowed, and this ?= effectively uses ifeq($(origin X),defined). A little nit picking, sorry.

In make/common/shared/Defs.gmk, you define HOST_CC and have another "error" line. I'd rather not
have the check in this file, but we should just define HOST_CC if not defined, and have HOST_CC checked
in Sanity.gmk in a special embedded sanity check where you verify all embedded requirements you might have.
We should probably also add some of these embedded variables added to Sanity-Settings.gmk so we can see
the settings when 'make sanity' is run.

Sanity.gmk changes completely turns off the compiler version check, if you really want to do this, perhaps
the better approach is to put this sanity check in a ifdef REQUIRED_CC_VER and then have you  not define
that variable in Defs-versions.gmk? If you are saying you want NO required version, then not defining
the REQUIRED_* variables seems like a good idea.

In java/zip/Makefile maybe we need a LIBZIP_CAN_USE_MMAP functionality option here?
Then embedded wouldn't even need to be mentioned here.

In Version.java.template You have added a "Java (TM)" line, I think that needs to go. You should add that
in via the makefile somehow but I don't think it belongs in an OpenJDK build.

-kto


On Mar 7, 2011, at 2:14 AM, David Holmes wrote:

> http://cr.openjdk.java.net/~dholmes/7025066/webrev/
> 
> The SE-Embedded product is a combination of open and closed sources. To allow SE-Embedded to be built from standard OpenJDK sources we need to apply a number of changes to the SE 7 build system:
> 
> - support for building the hotspot client compiler only (hotspot already supports this, this is the JDK side of things)
> - support for doing cross-compilation (Linux only)
> - minimal support for ARM/PPC architectures in the open code that currently only knows about x86 and sparc
> - SE-Embedded specific build settings and targets (specifically the headful and headless reduced JRE images)
> 
> ---
> 
> These changes are obviously primarily for Oracle's benefit, but some aspects may be use of externally as well. The hope is that these changes won't have an adverse affect on any downstream OpenJDK builders, but until I get feedback on that I won't know.
> 
> Thanks,
> David Holmes
> SE Embedded Team
>