[libcxx-commits] [PATCH] D72959: Relative VTables ABI on Fuchsia

[Leonard Chan via Phabricator via libcxx-commits]

leonardchan marked an inline comment as done.
leonardchan added inline comments.


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Comment at: clang/lib/CodeGen/CGVTables.cpp:623
+    llvm::Constant *C, llvm::GlobalVariable *VTable, unsigned vtableIdx,
+    unsigned lastAddrPoint) const {
+  // No need to get the offset of a nullptr.
----------------
rjmccall wrote:
> There's already an `addRelativeOffset` on `ConstantArrayBuilder`; is that insufficient for some reason?  I think that, if v-table building were refactored so that the places that build components also add them to the v-table, we'd end up with a lot more flexibility for the ABIs.  We needed a similar sort of change for pointer authentication, which we haven't upstreamed to LLVM yet, but which you can see here:
> 
> https://github.com/apple/llvm-project/blob/apple/master/clang/lib/CodeGen/CGVTables.cpp
> 
> 
I actually did not know about this method, but it does seem to boil down to the same arithmetic used here. Will update to see if I can use the existing builders instead.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D72959/new/

https://reviews.llvm.org/D72959