wasm-ld crash running sockets.test_enet

[sbc100]

This crash made it through the rollers:

https://app.circleci.com/pipelines/github/emscripten-core/emscripten/13394/workflows/68e06e6f-fc5f-4135-9d37-1337aebc80df/jobs/426872

Its most likely related to the recent string merging change.

libtool: link: /usr/local/google/home/sbc/dev/wasm/emscripten/emcc -shared  -fPIC -DPIC  .libs/callbacks.o .libs/compress.o .libs/host.o .libs/list.o .libs/packet.o .libs/peer.o .libs/protocol.o .libs/unix.o .libs/win32.o   -lc  -O2   -Wl,-soname -Wl,libenet.so.1 -o .libs/libenet.so.1.0.3
emcc: warning: linking a library with `-shared` will emit a static object file.  This is a form of emulation to support existing build systems.  If you want to build a runtime shared library use the SIDE_MODULE setting. [-Wemcc]
emcc: warning: generating an executable with an object extension (.so).  If you meant to build an object file please use `-c, `-r`, or `-shared` [-Wemcc]
emcc: warning: ignoring unsupported linker flag: `-soname` [-Wlinkflags]
wasm-ld: /usr/local/google/home/sbc/dev/wasm/llvm-project/lld/wasm/Symbols.cpp:399: const lld::wasm::OutputSectionSymbol *lld::wasm::SectionSymbol::getOutputSectionSymbol() const: Assertion `section->outputSec && section->outputSec->sectionSym' failed.
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /usr/local/google/home/sbc/dev/wasm/llvm-build/bin/wasm-ld -o .libs/libenet.so.1.0.3 .libs/callbacks.o .libs/compress.o .libs/host.o .libs/list.o .libs/packet.o .libs/peer.o .libs/protocol.o .libs/unix.o .libs/win32.o /usr/local/google/home/sbc/dev/wasm/emscripten/cache/sysroot/lib/wasm32-emscripten/libc.a -L/usr/local/google/home/sbc/dev/wasm/emscripten/cache/sysroot/lib/wasm32-emscripten --relocatable -mllvm -combiner-global-alias-analysis=false -mllvm -enable-emscripten-sjlj -mllvm -disable-lsr
 #0 0x00007fdc53687363 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/local/google/home/sbc/dev/wasm/llvm-build/bin/../lib/libLLVMSupport.so.13git+0x19a363)
 #1 0x00007fdc536850ae llvm::sys::RunSignalHandlers() (/usr/local/google/home/sbc/dev/wasm/llvm-build/bin/../lib/libLLVMSupport.so.13git+0x1980ae)
 #2 0x00007fdc5368782f SignalHandler(int) Signals.cpp:0:0
 #3 0x00007fdc53d46140 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14140)
 #4 0x00007fdc53036ce1 raise ./signal/../sysdeps/unix/sysv/linux/raise.c:51:1
 #5 0x00007fdc53020537 abort ./stdlib/abort.c:81:7
 #6 0x00007fdc5302040f get_sysdep_segment_value ./intl/loadmsgcat.c:509:8
 #7 0x00007fdc5302040f _nl_load_domain ./intl/loadmsgcat.c:970:34
 #8 0x00007fdc5302f662 (/lib/x86_64-linux-gnu/libc.so.6+0x34662)
 #9 0x00007fdc538a2868 (/usr/local/google/home/sbc/dev/wasm/llvm-build/bin/../lib/liblldWasm.so.13git+0x54868)
#10 0x00007fdc5387ee12 lld::wasm::ObjFile::calcNewIndex(llvm::wasm::WasmRelocation const&) const (/usr/local/google/home/sbc/dev/wasm/llvm-build/bin/../lib/liblldWasm.so.13git+0x30e12)
#11 0x00007fdc5387bdde lld::wasm::InputChunk::writeRelocations(llvm::raw_ostream&) const (/usr/local/google/home/sbc/dev/wasm/llvm-build/bin/../lib/liblldWasm.so.13git+0x2ddde)
#12 0x00007fdc53892b7b lld::wasm::CustomSection::writeRelocations(llvm::raw_ostream&) const (/usr/local/google/home/sbc/dev/wasm/llvm-build/bin/../lib/liblldWasm.so.13git+0x44b7b)
#13 0x00007fdc538a8b79 lld::wasm::RelocSection::writeBody() (/usr/local/google/home/sbc/dev/wasm/llvm-build/bin/../lib/liblldWasm.so.13git+0x5ab79)
#14 0x00007fdc538a8d8a lld::wasm::SyntheticSection::finalizeContents() crtstuff.c:0:0
#15 0x00007fdc538b5c28 lld::wasm::(anonymous namespace)::Writer::run() Writer.cpp:0:0
#16 0x00007fdc538ac9a1 lld::wasm::writeResult() (/usr/local/google/home/sbc/dev/wasm/llvm-build/bin/../lib/liblldWasm.so.13git+0x5e9a1)
#17 0x00007fdc53873080 lld::wasm::(anonymous namespace)::LinkerDriver::linkerMain(llvm::ArrayRef<char const*>) Driver.cpp:0:0
#18 0x00007fdc5386c216 lld::wasm::link(llvm::ArrayRef<char const*>, bool, llvm::raw_ostream&, llvm::raw_ostream&) (/usr/local/google/home/sbc/dev/wasm/llvm-build/bin/../lib/liblldWasm.so.13git+0x1e216)
#19 0x0000000000403bdf lldMain(int, char const**, llvm::raw_ostream&, llvm::raw_ostream&, bool) lld.cpp:0:0
#20 0x00000000004037e0 main (/usr/local/google/home/sbc/dev/wasm/llvm-build/bin/wasm-ld+0x4037e0)
#21 0x00007fdc53021d0a __libc_start_main ./csu/../csu/libc-start.c:308:16
#22 0x00000000004034ba _start (/usr/local/google/home/sbc/dev/wasm/llvm-build/bin/wasm-ld+0x4034ba)
emcc: error: '/usr/local/google/home/sbc/dev/wasm/llvm-build/bin/wasm-ld -o .libs/libenet.so.1.0.3 .libs/callbacks.o .libs/compress.o .libs/host.o .libs/list.o .libs/packet.o .libs/peer.o .libs/protocol.o .libs/unix.o .libs/win32.o /usr/local/google/home/sbc/dev/wasm/emscripten/cache/sysroot/lib/wasm32-emscripten/libc.a -L/usr/local/google/home/sbc/dev/wasm/emscripten/cache/sysroot/lib/wasm32-emscripten --relocatable -mllvm -combiner-global-alias-analysis=false -mllvm -enable-emscripten-sjlj -mllvm -disable-lsr' failed (-6)
make: *** [Makefile:323: libenet.la] Error 1
emmake: error: 'make' failed (2)
FAIL

[kripken]

Commenting here to remind us to remove the workaround in #14222 when we can (when the LLVM issue is fixed).

[sbc100]

Yeah.. I'm in two minds about actually reverting that since --disabled-shared is the prefered/recommended way to target emscripten, but clearly there is some test coverage here that we were lacking elsewhere. If it can add a targetted test rather than reverting #14222 I think that would be nicer.

[kripken]

Makes sense, a targeted test sounds even better.

[sbc100]

Upstream fix is https://reviews.llvm.org/D102806