64-bit: Returning a multi-field structure by value does not work about emscripten

[kripken]

That source code works for me with both llvm-gcc and clang with various emscripten settings.

Can you paste the generated .ll and .js files?

[benob]

Here is the .ll file: http://pastebin.com/gtfAshzZ
and the .js file: http://pastebin.com/KrU6QYve

[kripken]

Looks like that is compiled as 64-bit? (target triple = "x86_64-unknown-linux-gnu" and many appearances of i64)

Emscripten doesn't support 64-bit code well, because it is a poor fit for JavaScript (JS integers are 32-bit, and while floats are 64-bit, the actual integers they can contain are only up to 53 bits or so).

Compiling the source with -m32 should make it work properly (you may need to install some 32-bit headers on your system).

Long-term, the solution for emscripten is to bundle our own headers and build only against them. We have an issue open for that.

[benob]

Thanks for the tip, it does work fine.

I changed the issue to reflect that it only affects 64-bit compliation.

[kripken]

I added a FAQ entry for this. Marking as closed since I don't think there is a way to properly fix this. 32-bit compilation is the way to go for now.