please review fix for 7116322, enhance javac make rule with a little bit of instrumentation

[Stuart Marks]

Thanks Kelly (and David).

Any objection if I were to push this into the TL forest? A test build on all 
the platforms (including Windows) was successful.

s'marks

On 11/29/11 11:13 AM, Kelly O'Hair wrote:
> Looks fine to me.
>
> -kto
>
> On Nov 28, 2011, at 8:00 PM, Stuart Marks wrote:
>
>>
>>
>> On 11/28/11 7:00 PM, David Holmes wrote:
>>> On 29/11/2011 10:42 AM, Stuart Marks wrote:
>>>> Please review this change to add to the javac make rule some messages
>>>> about the number of files being compiled, the current working directory,
>>>> and a new message to demarcate the end of javac output.
>>>>
>>>> This will help capture and analyze javac output, in particular, warning
>>>> messages.
>>>> diff -r 6fbd69f8e3ab make/common/Rules.gmk
>>>> --- a/make/common/Rules.gmk Fri Nov 18 09:03:43 2011 +0000
>>>> +++ b/make/common/Rules.gmk Mon Nov 28 16:34:34 2011 -0800
>>>> @@ -236,9 +236,10 @@
>>>> @if [ `$(CAT) $<.filtered | $(WC) -l` -ge 1 ] ; then \
>>>> $(ECHO) "# Java sources to be compiled: (listed in file $<)"; \
>>>> $(CAT) $<.filtered; \
>>>> - $(ECHO) "# Running javac:"; \
>>>> + $(ECHO) "# Running javac: `$(WC) -l<  $<.filtered` files; in `pwd`"; \
>>>
>>> Can we do this without running wc a second time?
>>>
>>> Also shouldn't the current working directory be known from when the current
>>> sub-dir is entered by make?
>>
>> We can store the result of wc in a shell variable, but it has to be part of the same command as the if-statement that uses it, since successive lines of a make rule are executed by different shells. I've done this; see below.
>>
>> The current directory can probably be deduced, but it's not as simple as tracking the current subdirectory. Often the current directory is arrived at after having left a subdirectory. For example, this rule is invoked after this fragment of enter/leave messages from make have occurred:
>>
>> make[2]: Entering directory `/home/smarks/src/jdk8-jdk/make/java/java'
>> make[3]: Entering directory `/home/smarks/src/jdk8-jdk/make/java/nio'
>> make[3]: Leaving directory `/home/smarks/src/jdk8-jdk/make/java/nio'
>>
>> The current directory is now ..../make/java/java which isn't from the most recent "Entering" message, nor is it the parent of the most recent "Leaving" message. In this case make/java/java/Makefile calls a recursive make in ../nio! So, a script would have to track all the enter/leave messages and keep a stack of directories entered and left in order to determine the current one. I could enhance the parsing scripts to do this, but it seems complex and error-prone.
>>
>> If you're concerned about build performance, it *might* save a fork to replace a call to `pwd` with a make variable reference to $(CURDIR). The wc refactoring also saves a fork of the cat command. (Though I admit I don't know whether these actually speed things up or whether any change is measurable.)
>>
>> Revised diff below. Note that I've indented the entire if-statement as well as its contents, which is why so many more lines are changed.
>>
>> s'marks
>>
>>
>>
>> diff -r 6fbd69f8e3ab make/common/Rules.gmk
>> --- a/make/common/Rules.gmk     Fri Nov 18 09:03:43 2011 +0000
>> +++ b/make/common/Rules.gmk     Mon Nov 28 19:40:34 2011 -0800
>> @@ -233,13 +233,15 @@
>>         @$(MKDIR) -p $(CLASSDESTDIR)
>>         @$(RM) $<.filtered
>>         @$(CAT) $<  | $(NAWK) 'length>0' | $(SORT) -u>  $<.filtered
>> -       @if [ `$(CAT) $<.filtered | $(WC) -l` -ge 1 ] ; then \
>> -         $(ECHO) "# Java sources to be compiled: (listed in file $<)"; \
>> -         $(CAT) $<.filtered; \
>> -         $(ECHO) "# Running javac:"; \
>> -         $(ECHO) $(JAVAC_CMD) -sourcepath "$(SOURCEPATH)" -d $(CLASSDESTDIR) @$<.filtered; \
>> -         $(JAVAC_CMD) -sourcepath "$(SOURCEPATH)" -d $(CLASSDESTDIR) @$<.filtered; \
>> -       fi
>> +       @numfiles=`$(WC) -l<  $<.filtered` ; \
>> +         if [ $$numfiles -ge 1 ] ; then \
>> +           $(ECHO) "# Java sources to be compiled: (listed in file $<)"; \
>> +           $(CAT) $<.filtered; \
>> +           $(ECHO) "# Running javac: $$numfiles files; in $(CURDIR)"; \
>> +           $(ECHO) $(JAVAC_CMD) -sourcepath "$(SOURCEPATH)" -d $(CLASSDESTDIR) @$<.filtered; \
>> +           $(JAVAC_CMD) -sourcepath "$(SOURCEPATH)" -d $(CLASSDESTDIR) @$<.filtered; \
>> +           $(ECHO) "# javac finished"; \
>> +         fi
>>         @$(java-vm-cleanup)
>>
>> clobber clean::
>