Btw do you know if msan support is planned for g++? ________________________________ From: Jonathan Wakely <jwakely.gcc@xxxxxxxxx> Sent: Monday, July 22, 2024 10:32 PM To: Phil Phil <heidegg@xxxxxxxxxxx> Cc: gcc-help <gcc-help@xxxxxxxxxxx> Subject: Re: Building libstdc++ for MemorySanitizer On Mon, 22 Jul 2024, 22:20 Phil Phil, <heidegg@xxxxxxxxxxx<mailto:heidegg@xxxxxxxxxxx>> wrote: But clang works with a g++ built libstdc++ right? Yes. Are there patches that eliminate msan false positives from a g++ built libstdc++? I don't know, what/where are the false positives? How would that work? G++ can't add msan instrumentation, because it doesn't support msan. ________________________________ From: Jonathan Wakely <jwakely.gcc@xxxxxxxxx<mailto:jwakely.gcc@xxxxxxxxx>> Sent: Monday, July 22, 2024 9:05 PM To: Phil Phil <heidegg@xxxxxxxxxxx<mailto:heidegg@xxxxxxxxxxx>> Cc: gcc-help@xxxxxxxxxxx<mailto:gcc-help@xxxxxxxxxxx> <gcc-help@xxxxxxxxxxx<mailto:gcc-help@xxxxxxxxxxx>> Subject: Re: Building libstdc++ for MemorySanitizer On Mon, 22 Jul 2024 at 21:55, Phil Phil via Gcc-help <gcc-help@xxxxxxxxxxx<mailto:gcc-help@xxxxxxxxxxx>> wrote: > > Greetings, > > I'm currently trying to build a large C++ project for MemorySanitizer with clang since g++ doesn't support MSan as far as I know. I currently try to build an instrumented libc++ so I don't get false positives for Msan. > > Now since some libs we use still link against libstdc++ I would like to ask if it is possible to build libstdc++ in the same way so it doesn't produce false positives with MSan and if there is a manual for it. No. Building libstdc++ with clang (or anything except the matching version of GCC that it's shipped with) is not officially supported. I know a few people have done it and got it working, but you need to hack the build yourself.
