llvm dev - Jan 2020 - Loading object files into the JIT and forcing them to link without symbol lookup.

Lets say I add an ObjectFile as in
RTDyldObjectLinkingLayer->add(object_file).    Is there a way to force the
runtime linker to link the ObjectFile?We are implementing Clasp, a Common Lisp
that uses llvm as the backend.   I'm exploring loading object files and
linking them at runtime rather than linking them into dynamic libraries and
loading those into our system (we currently do this).I'm using the new ORCV2
JIT and I've cobbled together a JIT by following Lang Hame's talk at the
2018 LLVM dev meeting.I can add object files to the linking layer - but I need
to lookup a symbol in the object file to get it to link.The problem is, Common
Lisp is a dynamic language.  We may end up loading the object file repeatedly.I
currently need to lookup a symbol to get it to link so that I can execute any
code.But if I use a fixed symbol - then I can only load the object file once
because after that I get a symbol clash.
Alternatively - is there a symbol linkage that will let me reload the object
file repeatedly and look up the address of the symbol in the new object
file?I've tried linkonce_odr - but that works once and then gives me the
address of the first symbol that was loaded, bypassing the linking of the object
file.I looked into the RTDyldObjectLinkingLayer code and
RTDyldObjectLinkingLayer::runOutstandingMUs() appears to be what I want - but it
is a 'private' function in the RTDyldObjectLinkingLayer class and it
looks like it's marked for deprecation.
So - how do I get the linking effect of looking up a symbol without looking up a
symbol?Or how do I declare a symbol that I can lookup when I load ObjectFiles
repeatedly.


Christian Schafmeister
chris.schaf at verizon.net
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