Enabling Address Sanitizer causes runtime to exit despite `NO_EXIT_RUNTIME` being set

[cheinr]

I've been trying to get the address sanitizer working for a project I'm working on, and it appears to be causing the runtime to exit, even if I set NO_EXIT_RUNTIME.

Here's an example program that does something asynchronously:

// main.c
#include <stdio.h>
#include "emscripten.h"

int main() {
  EM_ASM({
      setTimeout(() => {
          const foo = cwrap('foo', null, null, { async: false });
          foo();
        }, 5000);
    });

  return 0;
}

EMSCRIPTEN_KEEPALIVE void foo() {
  printf("blam!\n");
}

For the latest version of emscripten (3.1.5), I get the following when I don't provide the -fsanitize=address flag:

> emcc -s ALLOW_MEMORY_GROWTH main.c 
> node a.out.js
blam!   // (after 5 seconds)

However, when the address sanitizer is enabled the program exits immediately without waiting for the async operation:

> emcc -s ALLOW_MEMORY_GROWTH -fsanitize=address main.c 
> node a.out.js
> (no output)

This occurs even if I add -s NO_EXIT_RUNTIME=1 when compiling. I've also tried using emscripten versions 3.0.0 and 2.0.0. 3.0.0 had the same behavior, but 2.0.0 worked as I would have expected with the fsanitize=address flag enabled, so I'm assuming this might be a regression?

[sbc100]

Ah, I think this might be a bug. -fsanitize=address should default to enabling EXIT_RUNTIME but it should no override your command line settings. I hope/think this will not occur if you use -sEXIT_RUNTIME=0 (which is logically the same as -sNO_EXIT_RUNTIME).

Regardless we should fix the way to handle defaulting settings to handle this case.