Shark: Update to LLVM 4.2, add debugging

[Andrew Haley]

Gary Benson wrote:
> Andrew Haley wrote:
>> This bumps Shark to use LLVM 4.2.  A few changes were needed, in
>> particular a workaround for a heinous LLVM bug
> 
> This is all the pointer_constant stuff?  Did you say that bug was
> fixed in the latest svn? 

Yes, yes.

> If so, is this something that should be reverted at a later date?

I don't know, really: IMO it would be far cleaner not to keep casting
pointers and intptr_t back and forth, but it doesn't much matter.

>> ...it will run various benchmarks and it will also run Eclipse,
>> at least until the JIT runs out of memory.
> 
> Is this http://icedtea.classpath.org/bugzilla/show_bug.cgi?id=219 ?
> 
>>    };
>>
>>    enum FrameType {
>> -    ENTRY_FRAME = 1,
>> +    ENTRY_FRAME = 0xCAFEBABE,
>>      INTERPRETER_FRAME,
>>      SHARK_FRAME,
>>      DEOPTIMIZER_FRAME
> 
> What was this for?

It makes it a bit easier to debug stack dumps; it makes no difference
otherwise.

Andrew.