[Lldb-commits] [PATCH] D65561: SymbolVendorELF: Perform build-id lookup even without a debug link

Sun Aug 4 13:59:53 PDT 2019

jankratochvil requested changes to this revision.
jankratochvil added a comment.
This revision now requires changes to proceed.

I find it as a performance regression that even with an unstripped full debug info file (clang -g) LLDB has now started to look for the separate debug info file based on its build-id:

  stat("/home/jkratoch/t/.build-id/f9/bf63a422425da856baacfadaa4a4afe43c991c.debug", 0x7ffe7f496470) = -1 ENOENT (No such file or directory)
  stat("/home/jkratoch/t/.build-id/f9/bf63a422425da856baacfadaa4a4afe43c991c.debug", 0x7ffe7f4968d0) = -1 ENOENT (No such file or directory)
  stat("/home/jkratoch/t/.build-id/f9/bf63a422425da856baacfadaa4a4afe43c991c.debug", 0x7ffe7f496690) = -1 ENOENT (No such file or directory)
  stat("/usr/lib/debug/.build-id/f9/bf63a422425da856baacfadaa4a4afe43c991c.debug", 0x7ffe7f496470) = -1 ENOENT (No such file or directory)
  stat("/usr/lib/debug/.build-id/f9/bf63a422425da856baacfadaa4a4afe43c991c.debug", 0x7ffe7f4968d0) = -1 ENOENT (No such file or directory)
  stat("/usr/lib/debug/.build-id/f9/bf63a422425da856baacfadaa4a4afe43c991c.debug", 0x7ffe7f496690) = -1 ENOENT (No such file or directory)

Any needless file lookups are reported as a performance problem on NFS-mounted disks.
Existence of `.gnu_debuglink` is considered as a flag marking files which did have debug info which is now split out.
Maybe you could explain what is the real goal.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D65561/new/

https://reviews.llvm.org/D65561