Can I somehow build webassembly code *without* the emscripten "glue"?

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Can I somehow create a wasm file, that will work on its own as described in MDN here (by instatiating the objects and calling functions on them)?

All the guides I can find (such as this one on MDN) recommend using emscripten; that will, however, also include ~70kB "glue code" (with ~50 kB optional filesystem emulation), that has additional logic (like detection node/browser environment and automatic fetching etc), and probably some other emulation.

What if I don't want that "glue code" and want to just create WASM directly (probably from C code, but maybe something else)? Is that possible right now?

emscripten webassembly javascript
5 Answers

LLVM now supports direct compilation of C to wasm using WASI. Emscripten is no longer necessary.

If no libc is required, you can use LLVM right out of the box. For example, the file foo.c can be compiled with:

clang --target=wasm32 --no-standard-libraries -Wl,--export-all -Wl,--no-entry -o foo.wasm foo.c

Otherwise, the WASI-libc project has a standalone libc that can be used.

A complete procedure for compiling C to WebAssembly with LLVM and running it in a browser is available in this post.

Rich_Apodaca_544260

UPDATE 2020

With Emscripten you can use -o my_file.wasm

That way you will have only the WASM file and if you use the flag STANDALONE_WASM it will create the .wasm AND an OPTIONAL .js glue code if needed.

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