[llvm] [DebugInfo][DWARF] Bounds-check the unit-index parallel table (PR #213285)

[David Spickett via llvm-commits]

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@@ -159,6 +159,8 @@ bool DWARFUnitIndex::parseImpl(DataExtractor IndexData) {
     auto Index = IndexData.getU32(&Offset);
     if (!Index)
       continue;
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DavidSpickett wrote:

In other words if Header.NumUnits is N, by the end of this loop we should have found a set of Indexes consisting of 1 through N (or N+1?). If not, something is invalid.

Duplicates may be its own separate thing. I don't know if it would be a valid thing to have.

https://github.com/llvm/llvm-project/pull/213285