[PATCH] D70350: [DWARF] Allow cross-CU references of subprogram definitions

[Vedant Kumar via Phabricator via llvm-commits]

vsk planned changes to this revision.
vsk marked an inline comment as done.
vsk added inline comments.


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Comment at: llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp:191
 bool DwarfUnit::isShareableAcrossCUs(const DINode *D) const {
   // When the MDNode can be part of the type system, the DIE can be shared
   // across CUs.
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aprantl wrote:
> Technically DISubprogram that are function definitions aren't part of the type system (as opposed to function declarations). Maybe just the comment needs to be reworded, but I wonder if this could have some unintended consequences when `llvm-link`ing two llvm::Modules that both define different functions with the same name.
> 
> What decision is `isShareableAcrossCUs()` used for?
`isShareableAcrossCUs` is used to figure out whether to whether a DIE can be retrieved from the DwarfFile backing a DwarfUnit, it looks like.

If there were two modules which both defined functions with the same name, I'd expect the definitions to either be merged, or for at least one to be TU-local. If we were to treat all definitions as shareable, we might expose the TU-local one (not sure what/if any harm that would cause -- maybe messed up call site tags? -- but we should probably just sidestep the issue).


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  https://reviews.llvm.org/D70350/new/

https://reviews.llvm.org/D70350