[PATCH] D145816: [BPF] Improve pruning to avoid generate more types in BTF

[Eduard Zingerman via Phabricator via llvm-commits]

eddyz87 added inline comments.


================
Comment at: llvm/lib/Target/BPF/BTFDebug.cpp:897
           } else {
+            if (CheckPointer && DTy->getTag() == dwarf::DW_TAG_pointer_type) {
+              SeenPointer = true;
----------------
Looks reasonable.

To be honest, I find the logic with `CheckPointer` / `SeenPointer` a bit confusing. As far as I understand the main thing is the following code:

```
void BTFDebug::visitDerivedType(...) {
  if (CheckPointer && !SeenPointer) {
    SeenPointer = Tag == dwarf::DW_TAG_pointer_type;
  }

  if (CheckPointer && SeenPointer) {
    // generate forward declaration
    return;
  }
  ...
  if (Tag == dwarf::DW_TAG_member)
    visitTypeEntry(DTy->getBaseType(), TempTypeId, true /* !! */, false);
  else
    ...
}
```

And setting `CheckPointer` to `true` means that visitor should generate forward declarations when possible. Adding a comment describing behavior of these parameters somewhere would be really helpful.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D145816/new/

https://reviews.llvm.org/D145816