[lld] r308544 - Speed up gdb index creation.

[George Rimar via llvm-commits]

>>Not sure. I would recommend doing another benchmark run. We have to
>>compare the delta from lld to lld --gdb-index to the delta from gold to
>>gold --gdb-index.
>>
>>Cheers,
>>Rafael
>
>I can do these benchmarks tomorrow.
>
>Also  going to look in profiler to check where it is
>slow downs now.
>
>George.

I did these benchmarks today, used clang objects and reproduce from clang-gdb-index folder
of lld-speed-test.tar.xz archive you posted earlier (thanks, btw !) and results are below:

* ld.gold with --gdb-index: 26.54s
* ld.lld     with --gdb-index: 15.33s
* ld.gold w/o --gdb-index: 21.65s
* ld.lld     w/o --gdb-index: 10.14s

Both LLD and ld.gold spends about 5 seconds for building gdb-index.

George.