[PATCH] D52634: [WebAssembly] Add DBG_VALUE with local operands location in WebAssemblyExplicitLocals pass

[Derek Schuff via Phabricator via llvm-commits]

dschuff added a comment.

@aprantl Is the advantage of your suggested approach just that we don't have to define a new expression type? Obviously the interpretation is not the same as DW_OP_breg on other targets so as you say, either way there would have to be special logic in all the tools that consume it. Is this kind of repurposing of builtin primitives common?



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Comment at: lib/CodeGen/AsmPrinter/DebugLocEntry.h:24
 
+struct TargetIndexLocation {
+  int Index;
----------------
This is very generic and doesn't really say what it's for, or what any of the fields are for. I get that this is trying to be target-independent but maybe it would be easier to understand if it wasn't.  It looks like the index corresponds now to the dwarf register (e.g. to indicate that this is for a local or global), and the offset to indicate which one, but that seems backwards because we use the term "index" to refer to e.g. the index of the global or local. 
Really what we have might in LLVM terms is a "kind" (i.e. a kind of location, local or stack or global) and an index (which local). "Index" is still a pretty generic term but it does match the usage of the term "index space" in the spec (and I would expect that our numbering should be the same, e.g. sharing the local index space for arguments and local variables).



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  https://reviews.llvm.org/D52634/new/

https://reviews.llvm.org/D52634