[LLVMdev] Linking modules across contexts crashes

[Yuri]

On 06/01/2015 11:43, Duncan P. N. Exon Smith wrote:
> You can round-trip to bitcode, reading the module into the
> destination context.  The following pseudo-code gives the idea:
>
>      bool linkModuleFromDifferentContext(Module &D, const Module &S) {
>        SmallVector<char, 256> Buffer;
>        writeBitcodeToBuffer(S, Buffer);
>
>        std::unique_ptr<Module> M = readBitcodeFromBuffer(D.getContext());
>        return Linker::LinkModules(&D, M.get());
>      }

Duncan,

Thanks for this workaround, i works. However, going to binary and back 
causes the significant bump in the process user time (14s->16s), while 
the wall clock time still lower due to parallelization.

There should be the function llvm::MergeContexts, similar to 
llvm::Linker::LinkModules. It should merge contexts as containers, with 
an error when this isn't possible, without changing most of the objects 
at all. It should cause the source context to disappear.

Yuri