Case in point: I recently learned that "#line 0" is a spec violation. A single OS revision of a single Android device refused to compile it. This is after shipping that line in every shader in multiple games for multiple years to millions of happy customers.

Apparently, Unreal Engine's boot process involves compiling a series of test shaders to determine which common compiler bugs the game needs to work around for this particular run.

This doesn't have anything to do with shaders as strings. It's been true since the beginning of shader programming, whether bytecode shaders or otherwise.

I can confirm this happens a LOT. (At least with ESSL) In it's defense, it usually is a mistake I made, but some implementations are definitely more lenient than others.

Parsing GLSL is quite hard. Thus, problems with drivers inconsistently rejecting GLSL text has been relatively common.

OpenGL's text requirement makes great sense in theory, but encouraged lots of problems in practice.

The fact that the GLSL standard forced every hardware vendor to vend a fully-functional compiler for a C-like language (even a simplified C-like language) is no small part of the source of that reputation.

But it has no authors! I assume it was a double-blind submission to ICFP, which required removing the author names. When posting it publicly, though, I think you should put the author names back on. You don't want your work floating around the internet without your names attached.

(I'm currently working on a Python hpc codebase with pyopencl and would be interested in reducing some of the manual labor required for cpu-gpu coordination)