-lc on wasm32-wasi-musl without `pub fn main` and with `-fno-entry` causes linker failure about not including proper main symbol

[MichaelBelousov]

Zig Version

0.14.0-dev.2851+b074fb7dd

Steps to Reproduce and Observed Behavior

This also occurs in 0.13.0 I just noticed.

1. create file main.zig:

export fn func() u32 {
    return 5;
}

2. build with command:

zig build-exe --export=func -fno-entry -lc -target wasm32-wasi-musl main.zig

3. I received the following output:

b22ac386e1/libc.a(/home/mike/.cache/zig/o/bdbc5e1f927e7d98a8e9ea2611c26b68/__main_void.o): undefined symbol: main

Expected Behavior

for an error about not including a pub fn main to surface instead of a linker error.

And it should just compile with -fno-entry passed

[rohlem]

I agree that it shouldn't come up as a linker error.
Are you saying there should still be an error about not including pub fn main though?
Shouldn't -fno-entry allow building a program without main?

[chearon]

I think maybe this file supposed to be conditionally added to the compile (not if .entry = .disabled):

zig/src/wasi_libc.zig

Line 506 in ea1ce2d

"wasi/libc-bottom-half/sources/__main_void.c",

As OP's output shows, the symbol is referenced in that file:

zig/lib/libc/wasi/libc-bottom-half/sources/__main_void.c

Line 5 in ea1ce2d

int __wasilibc_main(int argc, char *argv[]) asm("main");

The easy workaround is to stub out main. In my case, I'm building a C++ library to WASM, so I included this:

// wasi produces a reference to this in __main_void.c even though the linker
// won't call it with .entry = .disabled
int
main() {
  return 0;
}

That also removes unwanted "args_get" and "args_sizes_get" imports in the final .wasm.