[whopr] Design/implementation alternatives for the driver and WPA

[Devang Patel]

>> Also, returning a single object file restricts the possibilities.   
>> The
>> design of WHOPR, as I understand it, permits creating several
>> different object files in parallel based on a fast analysis of which
>> code should be compiled together.  When the linker supports  
>> concurrent
>> linking, it will be desirable to be able to provide it with each
>> object file as it is completed.

By definition, inter modular optimizer (aka lto) blurs object files  
boundaries. Typically, it will construct and walk combined call graph  
instead of dividing work based on input files. It does not add lots of  
value to preserve one to one direct relationship between optimizer  
input files and output files. I agree, it makes sense to have an  
additional interface to incrementally feed linker optimized chunks of  
code to take advantage of concurrent linking supported by the linker.

-
Devang