Emscripten: Sourcemap comment not added to .js file with -s WASM=1

[ghost]

Hi,

When I compile my project with -s WASM=1 the//# sourceMappingURL= is missing in the .js file. But the .map file is generated correctly.

I have no problem when I compile to asm.js.

emcc (Emscripten gcc/clang-like replacement) 1.37.22 (commit d3a5609c5f1cf786de9e205a154e1ffacd80a173)

[kripken]

The source map integration stuff should be in the wasm file, not the JS, I believe, when building to wasm. cc @yurydelendik to make sure.

[yurydelendik]

The WebAssembly source maps proposal is at https://github.com/WebAssembly/design/pull/1051 . The source map can be referenced from the WASM file itself.

See also examples at https://github.com/yurydelendik/sqlite-playground/blob/master/Makefile (demo at https://yurydelendik.github.io/sqlite-playground/src/playground.html) and https://github.com/yurydelendik/old-man-sandbox/tree/master/rust-wasm-hey (demo at http://yurydelendik.github.io/old-man-sandbox/rust-wasm-hey/hey.html)

[ghost]

OK, thanks. After taking a look of the hexdump of my .wasm file, I see trace of sourceMappingURL, but is there an option to set this URL when I compile?

[kripken]

I think --source-map-base does that.

[ghost]

Perfect, thanks for your help. It seems only Firefox Developer Edition can handle source map reference from .wasm? I was not able to see my C++ files in Chrome or standard Firefox.

[newnon]

It's better to fill sourcesContent with real file content as it done in rust sample.
just compare files from emscripten with C
https://yurydelendik.github.io/sqlite-playground/build/playground.wasm.map
and rust
https://yurydelendik.github.io/old-man-sandbox/rust-wasm-hey/hey.wasm.map
rust has sourcesContent section
May be it is some additional flag or something similar for that
@yurydelendik is it some kind of magic how do you fill sourcesContent section?

[Becavalier]

Currently, this feature still only working on Firefox Developer Edition.