Fixes for sanity-compiler-gcc and detection of linux variant

[Kelly O'Hair]

On Nov 12, 2010, at 3:14 PM, Mike Duigou wrote:

>
> On Nov 6 2010, at 07:07 , David Holmes wrote:
>
>>> 6998016: Incorrect ifdef nesting in sane-gcc-compiler rule
>>>
>>> http://cr.openjdk.java.net/~mduigou/6998016.0/webrev/
>>
>> In Defs-linux.gmk I must be missing something:
>>
>> ifneq "$(origin ALT_GCC29_COMPILER_PATH)" "undefined"
>>
>> and
>>
>> ifdef ALT_GCC29_COMPILER_PATH
>>
>> seem completely equivalent. The latter is simpler of course.
>
> That's the conclusion I came to as well after scratching my head for  
> a couple minutes to figure out why $(origin ) was used in this  
> specific case. The change is to minimize future head scratching.


The     ifneq "$(origin ALT_GCC29_COMPILER_PATH)" "undefined"
means that the variable was defined to something, potentially the  
empty value.
The    ifdef ALT_GCC29_COMPILER_PATH
means that the variable is defined to a non-empty value.
At least that's what I understand it to mean.
I have no objection to the change, I vaguely recall adding the use of  
this $(origin) and it had
something to do with allowing an empty value in this variable.
This and the ALT_COMPILER_PATH were variables that were potentially  
empty, or a path ending in /
so that you would use $(ALT_COMPILER_PATH)gcc  and if it was empty,  
gcc would come from PATH.
Personally, these things are a pain, hotspot makefiles ignores it, and  
on Windows you are forced to have
the compiler in PATH anyway.

-kto

>
>> In Sanity.gmk ... when I reported this problem it was stated that  
>> the correct fix was to swap the order of these two lines:
>>
>> 1486 ifeq ($(PLATFORM), solaris)
>> 1487   ifndef OPENJDK
>>
>> Not saying what you have is wrong, just different to what was  
>> stated previously.
>
> That organization does make more sense.
>
>> Also note the comment at 1483 is out of date as it only refers to  
>> Solaris.
>
> I've now corrected the comment to make it clear that these sanity  
> tests are about the OJI plugin.
>
> Updated webrev at http://cr.openjdk.java.net/~mduigou/6998016.1/ 
> webrev/
>
> Mike