32-bit support

[anuraaga]

When building for Wasm in go-pgquery, I hadn't noticed the values in pg_config.h that are hard-coded for 64-bit architectures (Wasm is 32-bit).

https://github.com/pganalyze/libpg_query/blob/16-latest/src/postgres/include/pg_config.h#L680

With PG 15, this didn't seem to cause any issues, but when updating to PG 16 I found compilation errors relating to sizeof(DATUM) being the same as sizeof(int) which makes sense given that configuration. So I patched the config with various values for a 32-bit architecture

https://github.com/wasilibs/go-pgquery/blob/main/buildtools/wasm/patch.txt#L67

I was a bit surprised to see I had to implement pg_popcount32 - though IIUC, the source import process effectively compiles the code, meaning that only code referenced from the config end up in this repo, so 32-bit codepaths get erased.

I was wondering if it wouldn't be possible to include at least pg_popcount32 in the source? That allows only needing to do the config change for 32-bit, without actual business logic changes.

If it's not a priority to support 32-bit, no worries just wanted to check, and also leave a record for anyone else compiling to Wasm.

[lfittl]

I was wondering if it wouldn't be possible to include at least pg_popcount32 in the source? That allows only needing to do the config change for 32-bit, without actual business logic changes.

Thanks for raising this!

I had forgotten that WASM uses 32-bit, which may be an argument to pay at least a bit more attention to it.

See #232 -- I think that should make things work (at least it does for me on a regular emulated 32-bit container running the latest Debian).