What is the xawt sizer wrapper, really?

[David Holmes]

Hi Magnus,

Yes I've also run afoul of this when cross-compiling - mostly recently 
when we started doing 32-bit cross-compiles (for arm) on 64-bit x86.

As I understand this, sizers is to X11 Java code what the UnixConstants 
program is to the filesystem code. It has to determine various sizes of 
native data structures used by X11 so that those values can be handled 
correctly in the Java code (storing pointer and offsets in Java code to 
pass ot native). Unlike the UnixConstants these values only seem to 
differ between 32-bit and 64-bit, not across different OS, so our 
cross-compilation can use the data produced by sizers executing on the 
build host. (For UnixConstants we did have to bypass when 
cross-compiling and have generated Java classes checked in the repo - 
which isn't satisfactory either.

David

On 14/06/2012 7:12 PM, Magnus Ihse Bursie wrote:
> We've had series of recurring issues with the xawt sizer wrapper (as
> defined in jdk/make/sun/xawt/Makefile) -- we've called it the
> X11Wrapper, I'm not sure if it has any other, more proper name.
>
> First of all, I must ask: what is the purpose of this? Does anybody here
> know, and can explain?
>
> The logic of this makefile is quite convoluted, with multi-step
> generation and execution. Is this really neccessary?
>
> The real problem, from our point of view, is not the complex
> generate/run/generate scheme -- make handles that for us. The problem is
> the interaction between the build and target platform, and the reason
> for having both 32 and 64-bit versions.
>
> Appearantly, we build both a 32 and a 64 bit version on some platforms,
> and then try to execute both. This works with varying degree of success
> depending on what build OS you're using and how it is configured. :-)
>
> Do we really need to do this? And why?
>
> Also, for 64-bit solaris we compare the generated file with a checked-in
> version, and if it differs, the build fail! So in reality, on this
> platform, we're not really doing real build work, but rather verifying
> that the build system looks like expected. But this is something that
> should be done in configure, rather as part of the build. If this is the
> real reason for this wrapper, could we perhaps generate these
> sizes-files for all platforms and check them in, and just verify them as
> part of configure?
>
> /Magnus
> (who have been working hard with the X11Wrapper for quite some time and
> still is totally confused about it's purpose and workings)
>