Quick report: I tried enabling ubsan (SANITIZER=undefined) by default for debug builds of yosys, but when checking the clean build time, it turned out it increased from 64 to 100 seconds on my system, so I no longer want to push that onto others. I’ll continue building debug builds with ubsan for myself. This was going to be the PR description:
ubsan is a lightweight sanitizer. For debug builds, it adds more information in cases of segfaults and catches more bugs than would trigger segfaults. Some languages like Zig even build debug builds with ubsan by default. I think we can have a better default developer experience if we enable ubsan when
ENABLE_DEBUG=1is set. This can still be overridden ifSANITIZER=is also explicitly set in the makefile invocation or Makefile.conf