Handling of metadata in llvm::CloneModule

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1

Sorry if this has been discussed already...

I am trying to understand whether there is an underlying reason why llvm::CloneModule takes argument function ShouldCloneDefinition to discriminate on objects being cloned, but blindly copies all named metadata...?

In my case this results in debug nodes that are creating uses/relocations for global objects that were _not_ copied per ShouldCloneDefinition...

Before I jump head on into unfamiliar code, I would like to understand why this wheel was not invented in the first place :slight_smile:

Thanks.

Sergei Larin

P.S. Also, if this does need fixing, please suggest the proper strategy for it... Thanks.

2

Hi Sergei,

The issue of importing only the minimum amount metadata is really non-trivial. You may want to have a look at:

Login [ThinLTO] Link in only necessary DICompileUnit operands

3

I was afraid of that...

Can I approach it from a different direction and clean up "dead" debug nodes in the module split code? That should be possible in the fashion of StripDeadDebugInfo (lib/Transforms/IPO/StripSymbols.cpp)

I currently is unable to link splitted module when -g is used...

Sergei