[PATCH] D54802: [LLD][COFF] Generate import modules in PDB

Wed Nov 28 07:45:38 PST 2018

aganea added a comment.

Sorry that was the wrong timings - that was for MSVC-built LLD. With Clang 7.0 things are a bit better in reality:

    Input File Reading:          1658 ms (  4.7%)
    Code Layout:                  621 ms (  1.8%)
    PDB Emission (Cumulative):  30380 ms ( 86.7%)
      Add Objects:              22615 ms ( 64.6%)
        Type Merging:           19205 ms ( 54.8%)
        Symbol Merging:          3385 ms (  9.7%)
      TPI Stream Layout:          897 ms (  2.6%)
      Globals Stream Layout:     1418 ms (  4.1%)
      Commit to Disk:            4559 ms ( 13.0%)
    Commit Output File:          1717 ms (  4.9%)
  -------------------------------------------------
  Total Link Time:              35021 ms (100.0%)

I noticed by the way that the default cmake config for Clang/LLVM/LLD comes with /INCREMENTAL and /MD (dll CRT) active. This causes a lot of thunking. I changed that to /INCREMENTAL:NO and /MT and things are a lot better - I'll send another review for that.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D54802/new/

https://reviews.llvm.org/D54802