Yuanfang Chen 728cc71092 [IRMover] Avoid materializing global value that belongs to not-yet-linked module ... We saw the same assertion failure mentioned here https://bugs.llvm.org/show_bug.cgi?id=42063 in our internal tests. The failure happens in the same circumstance as D47898 and D66814 where uniqueing of DICompositeTypes causes `Mapper::mapValue` to be called on GlobalValues(`G`) from a not-yet-linked module(`M`). The following type-mapping for `G` may not complete correctly (fail to unique types etc. depending on the the complexity of the types) because IRLinker::computeTypeMapping is not done for `M` in this path. D47898 and D66814 fixed some type-mapping issue after Mapper::mapValue is called on `G`. However, it seems it did not handle some complex cases. I think we should delay linking globals like `G` until its owing module is linked. In this way, we could save unnecessary type mapping and prune these corner cases. It is also supposed to reduce the total number of structs ending up in the combined module. D47898 is reverted (its test is kept) because it regresses the test case here. D66814 could also be reverted (the `check-all` looks good). But it looks reasonable anyway, so I thought I should keep it. Also tested the patch with clang self-host regularLTO/ThinLTO build, things look good as well. Reviewed By: tejohnson Differential Revision: https://reviews.llvm.org/D87001		2020-10-07 18:14:07 -07:00
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CMakeLists.txt
IRMover.cpp	[IRMover] Avoid materializing global value that belongs to not-yet-linked module	2020-10-07 18:14:07 -07:00
LinkDiagnosticInfo.h
LinkModules.cpp
LLVMBuild.txt