RFR: JDK-8176785 Add build support to generate PNG file from .dot file

[Mandy Chung]

> On Apr 7, 2017, at 4:02 AM, Erik Joelsson <erik.joelsson at oracle.com> wrote:
> 
> Hello,
> 
> This looks good in general. One thing I don't like about this is that if full docs is enabled, the docs-javadoc target now requires the full exploded image to be built first. I think that's unfortunate. Would it be possible to introduce separate targets for the gengraphs parts so that the main javadoc call can be run independently of most of the rest of the build, using the existing docs-javadoc target (and the newer docs-reference, even though I think that name is bit strange in this context)?
> 

I agree with Erik that it’d be nice to separate the module graph generation
and enable it to run with javadoc generation in parallel.  That’s one reason
why docs-module-graphs was a separate target (I have no issue to take that
target out from Main.gmk).


> On 2017-04-07 10:40, Magnus Ihse Bursie wrote:
>> 
>> Summary of changes:
>> * A new option --enable-full-docs determines if module graphs should be created or not. (In the future, even more optional but "difficult" documentation work might be added to depend on this.) This is enabled by default is all prerequisites are present.


It might be okay to call this “full docs” when it includes the 
module graphs but I am not sure about the new option name.

Can I build OpenJDK with the docs with module graphs when I 
have Graphviz installed? I would think we need a configure 
option to specify my local path to `dot` that will enable
the module graph build.  Is it possible?

>> 
>> This code only affects the build system and documentation. I intend to push it to jdk9 using the "noreg-doc" RDP2 exception.
>> 

Yes this is makefile and docs-only change.  In addition, FC extension
request for JDK-8173303 covers this issue [1].

>> Bug: https://bugs.openjdk.java.net/browse/JDK-8176785
>> WebRev: http://cr.openjdk.java.net/~ihse/JDK-8176785-full-build-support-for-module-graphs/webrev.01
>> 

common/autoconf/jdk-options.m4
 172     if test "x$DTRACE_DEP_MISSING" = "xtrue"; then

What is DTRACE_DEP_MISSING? 

 158 # gengraphs tool.
 167     # generated by the gengraphs tool and store it in the target dir.

Nit: I prefer to name the tool as `GenGraphs` rather than gengraphs.

Mandy
[1] https://bugs.openjdk.java.net/browse/JDK-8173303?focusedCommentId=14064511&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14064511