Need reviewer - jdk7u-osx Mac sanity check fixes

[Kelly O'Hair]

On Dec 20, 2011, at 9:38 AM, Mike Swingler wrote:

> On Dec 20, 2011, at 8:43 AM, Kelly O'Hair wrote:
> 
>> On Dec 19, 2011, at 11:39 PM, Alex Strange wrote:
>> 
>>>> If you are restricting your builders to Mac OS X 10.7 now, you can actually cut over to using clang soon, since it has no known bugs compiling the JDK (right Alex? I'm not completely hallucinating this right?)
>>>> 
>>>> Regards,
>>>> Mike Swingler
>>>> Apple Inc.
>>> Clang works fine to compile jdk. However, the build for hotspot is very unclean and prints thousands of warnings, because clang enables more warnings by default than gcc. I resorted to building with "clang -w" as printing all the warnings actually resulted in a slower compile time than using llvm-gcc.
>>> 
>>> Cleaning the build up will take some work, but you should look into it as Clang is a much faster compiler and uses a newer version of the compiler backend.
>> 
>> Please don't fall into the trap of 'it compiles fine'. I'm all for using the latest and greatest compilers,
>> but when it comes to building something like hotspot, just be very very careful.
>> The fact that clang uses a newer compiler backend make me even more nervous for hotspot and everyone's
>> code generation playing well together at runtime.
> 
> Of course, it needs to be tested - but Apple has a demonstrated history of not letting any legacy technologies live on for long, and I want to ensure that JDK8 is on a supported compiler when it comes time to ship. Changing compilers mid-product cycle is never fun.

Agree completely, we need to move soon on this soon, just makes me paranoid.
Many people are unaware of the interactions of compiler generated code with hotspot generated code, and the nasty things it can uncover. :^(

-kto

> 
> Regards,
> Mike Swingler
> Apple Inc.
>