[PATCH] D74169: [WIP][LLD][ELF][DebugInfo] Skeleton implementation of removing obsolete debug info.

Fri Mar 20 05:55:29 PDT 2020

avl added a comment.

> I am also curious to learn how much + AllTargetsCodeGens + AllTargetsDescs + AllTargetsInfos + AsmPrinter can increase the size of lld executable in a -DBUILD_SHARED_LIBS=off build.

Currently, it has zero effect because of --gc-sections.

I asked about using AsmPrinter in lld to check whether there is a fundamental limitation for that. 
So far, I understood that the answer depends on the final results of the implementation.

> Doing a full DWARF rewriting can save intermediate files. But if the memory/time trade-off is not that appealing, a standalone tool (which can have more configuration options) may be more suitable. That said, we may need some prototype to verify these theories.

I am currently working on that prototype.

> How much do we sacrifice in link speed/peak memory usage/lld executable size in return for X% of .debug_* size saving?

When the prototype is ready, it would be possible to evaluate memory/time results.

I did another prototype(not based on dsymutil, though with a very similar idea) D67469 <https://reviews.llvm.org/D67469>. 
Its results are in llvm thread http://lists.llvm.org/pipermail/llvm-dev/2019-September/135068.html.

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D74169/new/

https://reviews.llvm.org/D74169