follow up of Bug #1388713 Thanks to bug 1385783, the hack no longer fails. This command is segfaulting: $ LD_PRELOAD=/data/jenkins/workspace/firefox-clang-lld-last/obj-x86_64-pc-linux-gnu/build/unix/elfhack/test-array.so /data/jenkins/workspace/firefox-clang-lld-last/obj-x86_64-pc-linux-gnu/build/unix/elfhack/dummy Segmentation fault (core dumped) core dump as attachment (debian 64b)

Here's what main looks like in that dummy: 00000000002010f8 <main>: 2010f8: 31 c0 xor %eax,%eax 2010fa: e9 01 ef df ff jmpq 0 2010ff: cc int3 Here's what it's expected to look like: 00000000000006e0 <main>: 6e0: 55 push %rbp 6e1: 48 89 e5 mov %rsp,%rbp 6e4: b8 00 00 00 00 mov $0x0,%eax 6e9: e8 b2 fe ff ff callq 5a0 <print_status@plt> 6ee: 5d pop %rbp 6ef: c3 retq And dummy.c is: extern __attribute__((visibility("default"), weak)) int print_status(); int main() { return print_status(); } This is what objdump -dr dummy.o looks like on my machine: 0000000000000000 <main>: 0: 55 push %rbp 1: 48 89 e5 mov %rsp,%rbp 4: b8 00 00 00 00 mov $0x0,%eax 9: e8 00 00 00 00 callq e <main+0xe> a: R_X86_64_PLT32 print_status-0x4 e: 5d pop %rbp f: c3 retq And what it looks like on yours: 0000000000000000 <main>: 0: 31 c0 xor %eax,%eax 2: e9 00 00 00 00 jmpq 7 <main+0x7> 3: R_X86_64_PLT32 print_status-0x4 The code is fine, but lld is completely dropping the weak symbol.

Did you file an LLD bug, Sylvestre?

I did: https://bugs.llvm.org/show_bug.cgi?id=34301 (I was on pto)

Thank you!

I am in touch with upstream, they are working on it. ETA end of the week.

Merged upstream: https://reviews.llvm.org/D37837 I retriggered the build with a correct version, the error message changed but still failing.