[gold] emit assembly listing from gold plugin on LTO stage
Summary:
Sometimes it's useful to emit assembly after LTO stage to modify it manually. Emitting precodegen bitcode file (via save-temps plugin option) and then feeding it to llc doesn't always give the same binary as original.
This patch is simpler alternative to https://reviews.llvm.org/D24020.
Patch by Denis Bakhvalov.
Reviewers: mehdi_amini, tejohnson
Reviewed By: tejohnson
Subscribers: MaskRay, inglorion, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D56114
llvm-svn: 350276