How to prevent wasi-sdk clang++ from inserting __wasm_call_ctors call to every exported function?

I'm building C++ WASM application using wasi-sdk (versions 17 and 20 tested) clang++ as a compiler. I'm running the WASM code using WAMR in a custom embedded runtime. I use WAMR build-in libc instead of wasi-sdk's one. The application does not have main() - it exports few functions that the runtime calls when necessary. The problem I have is that clang++ inserts calls to constructors of static objects to all of my entry points.

Sample code:
<!-- language: c++ -->

struct Bar
{
    Bar() {}
};

Bar bar;

extern "C" void foo() {}

The build command I use is:

/opt/wasi-sdk/bin/clang++ -Wl,--no-entry -Wl,--allow-undefined -Wl,--export=foo -nostdlib -lc++ -lc++abi test.cpp

This results WASM code that calls c'tors every time (showing only foo export):

  (func $foo (type 0)
    return)
  (func $foo.command_export (type 0)
    call $__wasm_call_ctors         <<< this is the problem
    call $foo)
  (export "foo" (func $foo.command_export)))

-nostdlib -lc++ -lc++abi are needed to get rid of wasi-sdk libc, but still provide it's C++ standard library. If I compile without these flags the export is as expected:

  (export "foo" (func $foo)))

Question: how to prevent clang++ from inserting calls to static object c'tors?

The problem was that -Wl,--no-entry removed _start function that normally calls __wasm_call_ctors. As static c'tors were now not called, clang decided to insert those wrappers to each and every exported function to ensure statics constructors are called. Apparently this is a feature - here's a good discussion about this: https://reviews.llvm.org/D62922.

So the solution is to

• use linker flags -mexec-model=reactor -nostdlib -lc++ -lc++abi
• provide wasm function _initialize that just calls __wasm_call_ctors
• call _initialize from the runtime as a 1st thing once the WASM module
  is loaded