The Compact C Type Format in the GNU toolchain [LWN.net]

The Compact C Type Format in the GNU toolchain

Posted Aug 7, 2019 9:27 UTC (Wed) by movement (subscriber, #871)
In reply to: The Compact C Type Format in the GNU toolchain by markjdb
Parent article: The Compact C Type Format in the GNU toolchain

Any reason you didn't use illumos's newer CTF tools, which also don't need a separate ctfconvert step for each .o?

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The Compact C Type Format in the GNU toolchain

Posted Aug 8, 2019 5:03 UTC (Thu) by markjdb (guest, #94056) [Link] (2 responses)

They still work by generating CTF for each CU, and then pairwise merging the CTF files. It is faster to generate the type graph directly from DWARF, or at least without using CTF as an intermediate representation.

The Compact C Type Format in the GNU toolchain

Posted Aug 8, 2019 8:53 UTC (Thu) by movement (subscriber, #871) [Link]

I see, thanks.

The Compact C Type Format in the GNU toolchain

Posted Aug 9, 2019 11:35 UTC (Fri) by nix (subscriber, #2304) [Link]

One of our motivations for getting this stuff in GCC is that it's even faster to not generate the DWARF at all, particularly as it is often so large that it overflows caches and now you're incurring disk write time for all that stuff, which if you only want the CTF is completely wasted. (Of course you can build both in if you want to, but you don't *have* to.)