invalid debug info types passed to LLVM sometimes

[andrewrk]

Right now we do ZigLLVMReplaceCompositeType for the DIType of error sets, which means that we have to replace all references to it before we actually use it. Right now we put all the references in an array and then iterate later over this and do the replacements. It's pretty easy to mess up, and there are a few places, involving 0 bit types, where we make copies of the DIType and forget to append to this array.

So a better solution is to make the DIType of types indirect, so that we can replace them and simultaneously update all references.

Search codebase for g->error_di_types.append(&entry->di_type);

Actual best solution, but which requires a lot of rewriting, is not resolving debug info types until after analysis. We'll do this in the self hosted compiler at least, potentially doing the rewrite on the c++ compiler later.

[andrewrk]

This isn't really a bug, it's a design flaw that can be fixed with some code reworking.