[PATCH] D76878: Implement new DW_OP_LLVM_* operations

Thu Apr 2 15:12:44 PDT 2020

scott.linder added a comment.
Herald added a subscriber: MaskRay.

In D76878#1950365 <https://reviews.llvm.org/D76878#1950365>, @probinson wrote:

> > The diff at https://reviews.llvm.org/D70523 served as the initial RFC
>
> That's not what we mean by an RFC; what we mean is a narrative writeup that is then posted to the appropriate -dev list (llvm-dev in this case).
>  Reviews do not get the visibility you want for a significant change or enhancement to how we use things like DWARF.  I can't say I noticed that previous review.
>
> Given you've already committed the writeup in the previous review, the post to llvm-dev could be short with a pointer to that doc.  But that way at least more of the people who care about DWARF will be aware of it.

That makes sense, I'll post a true RFC to the lists soon and we can go from there. I talked with Tony and he has nearly finished updating the proposal to be in the style of a typical DWARF issue, so I am going to hold off on posting to the list until that is done as it will change the structure of the document quite a bit.

In the mean time, I would like to ask if any of the reviewers have thoughts on how to reconcile the need for more new `DW_OP_` extensions than there is encoding space for. Currently we are proposing adding a `DW_AT_augmentation` which could be applied to `DW_TAG_compile_unit` which will essentially allow for us to say "this compile unit uses extension X", and as part of our definition of the extension we could indicate that we are using certain encodings that may already be in use elsewhere. Essentially this would be a way for extension vendors to multiplex over the same limited encoding space. I imagine we would carry this augmentation string in the DICompileUnit metadata.

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D76878/new/

https://reviews.llvm.org/D76878