forked from OSchip/llvm-project
a4817871d2
Polly was accidently modifying a debug info metadata node when attempting to generate a new unique metadata node for the loop id. The problem was that we had dwarf metadata that referred to a metadata node with a null value, like this: !6 = ... some dwarf metadata referring to !7 ... !7 = {null} When we attempt to generate a new metadata node, we reserve the first space for self-referential node by setting the first argument to null and then mutating the node later to refer to itself. However, because the nodes are uniqued based on pointer values, when we get the new metadata node it actually referred to an existing node (!7 in the example). When we went to modify the metadata to point to itself, we were accidently mutating the dwarf metatdata. We ended up in this situation: !6 = ... some dwarf metadata referring to !7 ... !7 = {!7} and this causes an assert when generating the debug info. The fix is simple, we just need to use a unique value when getting a new metadata node. The MDNode::getTemporary() provides exactly the API we need (and it is used in clang to generate the unique nodes). Differential Revision: http://reviews.llvm.org/D6174 llvm-svn: 221550 |
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| Polly.cpp | ||