[vetinari]

Is there a compelling reason for a browser JIT to comply with platform ABI? Third party binaries are not going to be linked in or called from the JIT-ted code anyway.

[yuhong]

Proper SEH support.

[vetinari]

But why? Only sandboxed, JIT-ted js code is going to use this custom ABI. What exceptions do you expect to handle?

[yuhong]

All exceptions including CPU exceptions like divide by zero or access violation uses SEH on Windows.

[pcwalton]

…which you shouldn't be getting in jitcode.