[llvm-dev] [LLD] Slow callstacks in gdb

Martin Richtarsky via llvm-dev llvm-dev at lists.llvm.org
Mon Nov 27 07:00:10 PST 2017


for programs linked with lld it's substantially slower to get callstacks
in gdb, in comparison to gold-linked programs. Two measurements:

lld     gold
15 sec  3 sec
6 sec   2 sec

This is a debug build, rather large binaries (lots of templates). I have
seen even worse performance for debug+UBSan builds. I think code size (and
therefore DWARF size) has an impact. Is there some information missing
that gdb needs, and only gold generates?

gdb version is 8. I tested lld 5.0 and an earlier 4.0 trunk version.

Note that these binaries do not use gdb indexing.

Has anyone seen something similar?

Best regards,

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