Hi Magnus,
On 21.5.2015 13:21, Magnus Ihse Bursie wrote:
Hi Erik and Jan,
Erik's modifications look much better to me.
I'm just not entirerly satisfied with how this new symbolgenerator tool
fits int our model. It's really a buildtool, similar to the other
buildtools we have.
First of all, the location is not really ideal. Compare with how the
java build tools are stored, e.g.
jdk/make/src/classes/build/tools/charsetmapping. Correspondingly, I
believe the symbolgenerator should live in
$TOP/make/src/classes/build/tools/symbolgenerator. This makes it clear
that it's source code, leaves room for native build tools, and sets up a
common package prefix (while build.tools.<foo> might not be ideal, it's
the same as in the JDK build tools, so let's keep it).
Sure - I'll move it.
Thanks,
Jan
Second, and this is more of a open question, mostly directed at Erik,
shouldn't we build the symbolgenerator tool at the buildtools phase? It
might require slightly more work to adapt the buildtools system for the
top level, but I believe it is much more in line with what we got.
/Magnus
On 2015-05-21 11:42, Erik Joelsson wrote:
Hello Jan,
On the build changes there are some things I would like to change.
* The creation of the ct.sym file should be done in a separate file,
with a separate top level target. The images target should just be
about linking and pulling things together, not actual
building/compiling of things.
* The calls to MakeDir are not needed.
* There are missing prerequisites in the rule for creating the symbols.
* The jar file creation should use the SetupArchive macro.
* Intermediate build files should be put into the $(SUPPORT_OUTPUTDIR).
* I think it makes sense to have the ct.sym file be part of the
exploded-image.
Since this was quite a lot of changes, I took the liberty of
implementing them. Here is a webrev with my suggestion for build changes:
http://cr.openjdk.java.net/~erikj/8072480/webrev.01/
/Erik
On 2015-05-21 09:01, Jan Lahoda wrote:
Hi,
This is a patch adding a new option, -platform, to javac.
Patch for the top-level repository is here:
http://cr.openjdk.java.net/~jlahoda/8072480/webrev.00/top-level/
Patch for the langtools repository is here:
http://cr.openjdk.java.net/~jlahoda/8072480/webrev.00/langtools/
These changes also require additional langtools changes as their
prerequisite:
http://cr.openjdk.java.net/~jlahoda/8080675/webrev.00/
Overall, one can imagine '-platform N' to have the same effect as
'-source N -target N -bootclasspath <APIs-for-N>'. The possible
values for 'N' are pluggable in a limited way, though (see
langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/platform/PlatformProvider.java).
Note that this patch only introduces N=7 and N=8, which correspond to
Open JDK 7 and 8 GA.
A tricky problem to solve is where to get the APIs for platform N.
The proposal is to include history data in the textual format inside
the OpenJDK repositories (the input data), process them at build time
and create a lib/ct.sym file holding the data in the JDK image. javac
running with the -platform option then compiles against the
lib/ct.sym file. The input history data are placed
<top-level-repository>/make/data/symbols (the sym.txt files). This
patches only includes data for OpenJDK 7 and 8, and only for public
APIs (more or less Java SE and JDK @Exported APIs).
The size of the history data is currently ~6MB in the JDK checkout
and ~650kB inside the .hg directory (the size could change
significantly if additional classes/elements, like non-public API
classes, would need to be included). The lib/ct.sym file is currently
~4.5MB.
The ct.sym file is a zip file containing signature files. The
signature files are similar to classfiles (so javac can read them as
classfiles), but are missing some attributes, most notably the Code
attribute. On the top-level, the ct.sym contains directories named
"7", "78" and "8". When compiling for version 'N', the bootclasspath
for that version is obtained by using directories which have 'N' in
their name.
The sigfiles for ct.sym are created by
<top-level-repository>/make/tools/symbolgenerator/CreateSymbols.java.
The same file can also be used to construct the sym.txt files.
Concise instructions are part of the CreateSymbols.java.
I am sending this as one review, as the changes together make one
feature, but the langtools and top-level changes are independent to a
great degree: the langtools changes add the "-platform" javac; and
the top-level changes add the history data and ability to build the
ct.sym file. If desired, these could be pushed and/or reviewed
independently.
Many thanks go to Jon Gibbons, Joe Darcy, Magnus Ihse Bursie, Alan
Bateman and others who have provided advices and help on the matter
before.
Any insights/comments are wholeheartedly welcome.
Thanks,
Jan
