Load the attached test case in a debug build (on Linux). you'll see these values: JavaScript warning: file:///media/storage/moz/emscripten/tests/out.html, line 6523: WebGL: bindBuffer: target: invalid enum value 0x100 JavaScript warning: file:///media/storage/moz/emscripten/tests/out.html, line 6523: WebGL: bufferData: target: invalid enum value 0x100 The 0x100 value is things like Module.ctx.ARRAY_BUFFER and Module.ctx.ELEMENT_ARRAY_BUFFER. Module.ctx is a WebGL context.

Hmm. I'm not seeing this on Mac, but that sounds like a pretty weird bindings issue.... or a JS issue. Is this happening in debug builds only?

Yes, I only saw this on a debug build. And I only tested it on Linux. Honestly this is very weird. It happens for all of the constants that I tested. I'm worried that this might be a memory corruption of some sort... :(

Can you reproduce this, or did it just happen the one time?

I just reproduced under a fresh build off of the latest mozilla-central.

OK. Is it reproducible reliably, or just happens sort of randomly?

Bisection shows that this is a regression from the patch for bug 748266. It happens reliably.

OK, this is clang miscompiling WebGLRenderingContextBinding.cpp. Specifically, the static initializer for sConstants_specs is miscompiled, and all of the UINT_TO_JSVAL functions are called with a value of 0x100. My current clang is based on revision 145546. I'll upgrade my clang to see whether that fixes this problem.

I can confirm that the bug is fixed in clang ToT.

(In reply to Ehsan Akhgari [:ehsan] from comment #9) > I can confirm that the bug is fixed in clang ToT. Is it fixed it 158158 or should we upgrade the bots to something newer? (see bug 761421).

(In reply to Rafael Ávila de Espíndola (:espindola) from comment #10) > (In reply to Ehsan Akhgari [:ehsan] from comment #9) > > I can confirm that the bug is fixed in clang ToT. > > Is it fixed it 158158 or should we upgrade the bots to something newer? (see > bug 761421). This bug is fixed in clang revision 158158, so no need to upgrade the bots to something newer.

[Triage Comment] Removing tracking due to bug resolved wontfix.

(In reply to Lukas Blakk [:lsblakk] from comment #12) > [Triage Comment] > Removing tracking due to bug resolved wontfix. Saved too fast, I meant 'worksforme'.