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by hawski 607 days ago
Is there a way to statically compile an application with SQLite and the result WASM was smaller. So for example I have an app that would use only a specific subset of SQLite. Could the SQLite's WASM be built with this in mind cutting down on code that is not used? Or is there a way to prune it having the used API surface?

In a regular compiler/linker scenario it would just be a static compilation. Here we have a JS app and WASM library.
2 comments
sgbeal 606 days ago
> Could the SQLite's WASM be built with this in mind cutting down on code that is not used?

The pending 3.47 release has some build-side tweaks which enable a user to strip it down to "just the basics," but we've not yet been able to get it smaller than about 25-30% less than it otherwise is:

    cd ext/wasm
    make barebones=1 ; # requires GNU Make and the Emscripten SDK
Doing that requires building it yourself - there are no plans to publish deliverables built that way.

The build process also supports including one's own C code, which could hypothetically be used to embed an application and the wasm part of the library (as distinct from the JS part) into a single wasm file. Its primary intended usage is to add SQLite extensions which are not part of the standard amalgamation build.

> Or is there a way to prune it having the used API surface?

Not with the provided JS pieces. Those have to expose essentially the whole C library, so they will not be pruned from the wasm file.

However, you could provide your own JS bindings which only use a small subset of the API, and Emscripten is supposedly pretty good about stripping out C-side code which neither explicitly exported nor referenced anywhere. You'd be on your own - that's not something we'll integrate into the canonical build process - but we could provide high-level support, via the project's forum, for folks taking that route.

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sgbeal 603 days ago
Correction:

    make barebones=1 ; # requires GNU Make and the Emscripten SDK
should be:

    make oz barebones=1 ; # requires GNU Make and the Emscripten SDK
otherwise it will build with -O0, resulting in huge wasm files.
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hoten 607 days ago
Since SQL takes arbitrary strings as input, this would require explicit compiler flags to disable the knobs you don't want. Can't rely on excluding unused symbols really.
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