[PATCH] D74169: [WIP][LLD][ELF][DebugInfo] Remove obsolete debug info.

[Alexey Lapshin via Phabricator via llvm-commits]

avl added a comment.

Re-measured size/performance results once more. These results are for 12-cores machine. Actually, the more cores the bigger difference between --gc-debuginfo/--no-gc-debuginfo cases.

A: --function-sections --gc-sections 
B: --function-sections --gc-sections --gc-debuginfo
C: --function-sections --gc-sections --fdebug-types-section
D: --function-sections --gc-sections --gsplit-dwarf
E: --function-sections --gc-sections --gc-debuginfo --compress-debug-sections=zlib 
F: --function-sections --gc-sections --fdebug-types-section --gc-debuginfo
(last case does not produce valid DWARF currently)

  LLVM code base:
  --------------------------------------------------------------
  | Options |    build time   |    bin size   |    lib size    | 
  --------------------------------------------------------------
  |    A    |    54min(100%)  |   19.0G(100%) |  15.0G(100.0%) |
  --------------------------------------------------------------
  |    B    |    65min(120%)  |    9.7G( 51%) |  12.0G( 80.0%) |
  --------------------------------------------------------------
  |    C    |    53min( 98%)  |   12.0G( 63%) |  15.0G(100.0%) |
  --------------------------------------------------------------
  |    D    |    52min( 96%)  |   12.0G( 63%) |   8.2G( 55.0%) |
  --------------------------------------------------------------
  |    E    |    64min(118%)  |    5.3G( 28%) |  12.0G( 80.0%) |
  --------------------------------------------------------------
  |    F    |    57min(105%)  |    7.6G( 40%) |  14.0G( 93.0%) |
  --------------------------------------------------------------
  
  
  Clang binary:
  -------------------------------------------------------------
  | Options |      size      |     link time  |  used memory  |
  -------------------------------------------------------------
  |    A    |    1.50G(100%) |    9sec(100%)  |  9307MB(100%) |
  -------------------------------------------------------------
  |    B    |    0.76G( 50%) |   72sec(800%)  | 15055MB(161%) |
  -------------------------------------------------------------
  |    C    |    0.82G( 54%) |    8sec( 89%)  |  8402MB( 90%) |
  -------------------------------------------------------------
  |    D    |    0.96G( 64%) |    6sec( 67%)  |  4273MB( 46%) |
  -------------------------------------------------------------
  |    E    |    0.43G( 29%) |   80sec(889%)  | 15000MB(161%) |
  -------------------------------------------------------------
  |    F    |    0.58G( 39%) |   30sec(334%)  | 10890MB(117%) |
  -------------------------------------------------------------
  
  
  lldb loading time:
  --------------------------------------------
  | Options |      time     |   used memory  |
  --------------------------------------------
  |    A    |  6.4sec(100%) |  1495MB(100%)  |
  --------------------------------------------
  |    B    |  4.0sec( 63%) |   826MB( 55%)  |
  --------------------------------------------
  |    C    |  3.7sec( 58%) |   877MB( 59%)  |
  --------------------------------------------
  |    D    |  4.3sec( 67%) |  1023MB( 69%)  |
  --------------------------------------------
  |    E    |  2.1sec( 33%) |   478MB( 32%)  |
  --------------------------------------------
  |    F    |  2.7sec( 42%) |   631MB( 43%)  |
  --------------------------------------------


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  https://reviews.llvm.org/D74169/new/

https://reviews.llvm.org/D74169