On Thu, Dec 22, 2016 at 05:47:05PM +0100, Christian Weisgerber wrote: > Building ld.so with clang on amd64 fails with undefined references > to memset and memcpy. That is odd, since neither function appears > in the source. Apparently clang optimizes the _dl_memset and > _dl_bcopy functions into calls to memset and memcpy, respectively. > > I tentatively propose to add -fno-builtin to fix this. > (Builds, runs, and passes regress with gcc on amd64 and i386.)
You are lucky if it fixes the problem, infact, -fno-builtin has quite a chance to make the problem worse. Clang assumes the same set of basic functions to be present even for -ffreestanding environments and can lower e.g. initialisation of local variables to memset/memcpy. Joerg
