Performance: Extend `short_big_int` to `int64_t`

[CarterLi]

bellard does this

https://github.com/bellard/quickjs/blob/e182e3df5c51017a7faa97a654b3f2b9c6330448/quickjs.h#L221-L225

while quickjs-ng uses int32_t only

quickjs/quickjs.h

Line 315 in bcac5c2

int32_t short_big_int;

[saghul]

IIRC that was a conscious decision to simplify the implementation.

[CarterLi]

IMO 64-bit short_big_int is very useful when exposing (u)int64_t variables in C to javascript

quickjs-ng using int32_t only results in lower performance than the original project. doesn't it?

[saghul]

Likely yes, in microbenchmarks.

Do you have a real world use case that gets heavily impacted? We need to see some numbers.

[CarterLi]

No. As I said before, I'm still experimenting quickjs-ng and trying to integrate it to my project.

I'm finding this when investigating a compiler warning:

/opt/homebrew/include/quickjs.h:380:25: warning: implicit conversion loses integer precision: 'int64_t' (aka 'long long') to 'int32_t' (aka 'int') [-Wshorten-64-to-32]
  380 |     v.u.short_big_int = d;
      |                       ~ ^

I immediately realized that it can be improved for performance.

[saghul]

What compilation flags are you using? I'm not getting that warning on macOS.

PS: There are a lot of shuch warnings on Windows, alas.

[saghul]

Fix for the compilation warning: #1503