[all-commits] [llvm/llvm-project] 8825ff: [ELF] --time-trace: Trace "Write sections"

[Fangrui Song via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 8825ffdbde01941110b4f4ee3b7e8e129b9a2289
      https://github.com/llvm/llvm-project/commit/8825ffdbde01941110b4f4ee3b7e8e129b9a2289
  Author: Fangrui Song <i at maskray.me>
  Date:   2021-12-20 (Mon, 20 Dec 2021)

  Changed paths:
    M lld/ELF/OutputSections.cpp
    M lld/ELF/Writer.cpp

  Log Message:
  -----------
  [ELF] --time-trace: Trace "Write sections"

writeSections is typically a bottleneck.
This was used to track down the following bottlenecks:

* Output section .rela.dyn (9115d75117b57115fe45153e5f38f2c444c0cd91)
* Output section .debug_str (3aae04c744b03eb3eec7376f9d34fa3e42f8d108)
* posix_fallocate is slow for Linux tmpfs: D115957

Reviewed By: ikudrin

Differential Revision: https://reviews.llvm.org/D115984