Duncan P. N. Exon Smith a6c2e1e60b Linker: Move distinct MDNodes instead of cloning ... Instead of cloning distinct `MDNode`s when linking in a module, just move them over. The module linker destroys the source module, so the old node would otherwise just be leaked on the context. Create the new node in place. This also reduces the number of cloned uniqued nodes (since it's less likely their operands have changed). This mapping strategy is only correct when we're discarding the source, so the linker turns it on via a ValueMapper flag, `RF_MoveDistinctMDs`. There's nothing observable in terms of `llvm-link` output here: the linked module should be semantically identical. I'll be adding more 'distinct' nodes to the debug info metadata graph in order to break uniquing cycles, so the benefits of this will partly come in future commits. However, we should get some gains immediately, since we have a fair number of 'distinct' `DILocation`s being linked in. llvm-svn: 243883		2015-08-03 17:09:38 +00:00
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CMakeLists.txt
LinkModulesTest.cpp	Linker: Move distinct MDNodes instead of cloning	2015-08-03 17:09:38 +00:00
Makefile