[llvm-bugs] [Bug 38455] Optimizing to library calls with -ffreestanding and -O0

via llvm-bugs llvm-bugs at lists.llvm.org
Wed Nov 14 10:59:21 PST 2018


bzt <bztemail at gmail.com> changed:

           What    |Removed                     |Added
             Status|NEW                         |RESOLVED
         Resolution|---                         |WONTFIX

--- Comment #10 from bzt <bztemail at gmail.com> ---
Hi Tim,

I've made peace with clang not supporting some gcc features. I believe what
caused the problem is the undocumented -nolibc argument, somehow implied by
-nostartfiles (more precisely it's only documented for the GNU ld, but clearly
gcc won't generate calls to memcpy, memset etc. when used, therefore the issue
maybe not related to -ffreestanding).

I decided to go on with workarounds: I've implemented those memory functions
for all the architectures I work with, and now that I don't have linking
errors, and I don't care why memset is called in my meminit, everything is
working just fine (and there's no __builtin_trap() either with -O0). I have to
debug my run-time linker though, because lld generates a little bit different
ELF structures than GNU ld. But I'm sure that's on me, as I have made some
GNU-specific assumption in my code I was unaware of.

Anyway, I'd like to say thanks again for your help, and I think we can safely
close this issue.


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