[Lldb-commits] [PATCH] D145180: [lldb] Introduce new SymbolFileJSON and ObjectFileJSON

Fri Mar 3 11:01:53 PST 2023

JDevlieghere marked 4 inline comments as done.
JDevlieghere added a comment.

Thanks for the feedback Greg, they're all great suggestions.

In D145180#4166302 <https://reviews.llvm.org/D145180#4166302>, @clayborg wrote:

> From reading this it looks like your main use case is to supply additional symbols to an existing stripped binary. Is that correct?

That's one use case, the other one being the interactive crashlogs. I went into a bit a bit more detail in the summary.

> Are you aware that each dSYM file has a full copy of the unstripped symbol table already? It removes the debug map entries, but each dSYM copies all non debug map symbols inside of it already. So the same thing from this patch can already be accomplished by stripping a dSYM file of all debug info sections and leaving the symbol table alone, and then using this this minimal dSYM file just to get the symbols.

Yup and for the strip scenario I described above, we wouldn't even have to go through a dSYM, we could just have `llvm-strip` emit a Mach-O with only the unstripped symbol table and that should work out of the box in LLDB (similar to how you can add the unstripped binary with `target symbols add`). But for the crashlog use case where we only have an address and a symbol, it would be really tedious to have to build the whole symbol table. I really like the idea of a textual format for this and it's easy to read and modify. The barrier is super low and even if you had nothing but the textual output of `nm` you could create one of these JSON files and symbolicate your binary in LLDB.

> Any idea on where the JSON file will live if it is just a companion file for another mach-o or ELF executable? Will it always be next to the mach-o executable? Will we enable a Spotlight importer to find it like we do for dSYM files?

For now I have no plans to have LLDB pick these files up automatically, but that's definitely something we could explore in the future.

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D145180/new/

https://reviews.llvm.org/D145180