[PATCH] D46271: [CodeView] Improve debbuging of virtual base class member variables

[Reid Kleckner via Phabricator via llvm-commits]

rnk added a subscriber: dblaikie.
rnk added inline comments.


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Comment at: llvm/include/llvm/IR/DebugInfoMetadata.h:793-794
 
+  /// \brief In inheritance, the pointer offset to virtual bases.
+  uint32_t VBPtrOffset;
+
----------------
`vbptroffset` is pretty esoteric. It seems really unfortunate to have to widen the very popular `DIDerivedType` constructor to take this obscure parameter. Pointer and reference types are some of the most common kinds of DIDerivedType nodes, so taking an address space is less objectionable, even though it is specialized towards one kind of derived type node.

I'd recommend encoding this information in the `extraData` field, similar to how we encode bit offsets for bitfields, or making a new `DIInheritanceType` node. @aprantl, @dblaikie WDYT?


https://reviews.llvm.org/D46271