On 2023-09-20 09:38, Andrew Leonard wrote:
Thanks Alan,
So different gcc, glibc, Xcode,.. agree, they need to be the same for
identical bits.
However, at the moment using the same toolchains, if you do a standard
product build,
and then a bootcycle build, of the same source, jrt-fs.jar will differ.
I'll do some investigation of the make files to see if a "Build JDK"
rebuild of jrt-fs.jar is
feasible.
I would not in general assume that a normal build and a bootcycle build
produce identical results. A bootcycle build will build the product
using a newer version of the JDK (viz. the one you just build from the
sources), and as such, changes to javac can result in different class
file outputs, etc. That being said, for large time periods of the JDK
source code, a normal build and a bootcycle build can certainly result
in the same output, since no changes have been made in the product that
affects how .class files are generated. But that is not guaranteed, nor
is a difference between normal and bootcycle build a sign of trouble or
a defect.
If jrt-fs.jar is consistently different between a bootcycle build and a
normal build, that sounds a bit odd, though. Especially since it should
be built with `--release 8` (or something like that) to ensure it is
usable on older Java; and that output ought not to really change as the
JDK develops.
(Also, questions about the build process is preferably handled on the
build-dev list)
/Magnus
Cheers
Andrew
On Tue, Sep 19, 2023 at 5:42 PM Alan Bateman <alan.bate...@oracle.com>
wrote:
On 18/09/2023 14:51, Andrew Leonard wrote:
> Thanks for the clarification Alan.
>
> To ensure the reproducibility of the whole JDK image regardless
of the
> specific bootjdk used, would it make sense once the "Build JDK" has
> been built, we re-build jrt-fs.jar again using the "Build JDK" ?
Thus
> jrt-fs.jar will be consistent with the rest of the image in
terms of
> what it is compiled with.
>
The boot JDK will be JDK N-1, or the newly built JDK in the case
of boot
cycle builds. It seems a bit of a stretch to have builds using
different
tool chains to produce identical bits but maybe you mean something
else.
In any case, for jrt-fs.jar the important thing is that they are
compiled to --release 8 (that might rev at some points) so that
IDEs/tools can open a target run-time image as a file system and
access
the classes/resources.
-Alan.
