[llvm] [NativePDB] Fix crash in llvm-pdbutil (PR #164871)

[Vladimir Gorsunov via llvm-commits]

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@@ -194,6 +194,8 @@ Error LazyRandomTypeCollection::visitRangeForType(TypeIndex TI) {
   }
 
   visitRange(TIB, Prev->Offset, TIE);
+  if (Records.size() <= TI.toArrayIndex())
+    return make_error<CodeViewError>("Type index too big");
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gv wrote:

The crash happens in `tryGetType` https://github.com/llvm/llvm-project/blob/9e7a3ee5ff85a6c6838b20734822d658744e9bf3/llvm/lib/DebugInfo/CodeView/LazyRandomTypeCollection.cpp#L106 when the index value goes outside the buffer. That's allowed to occur because `ensureTypeExists` doesn't return error when the index argument is too big. 

I put the check in `visitRangeForType` because it already does some TI validation for `ensureTypeExists` in line https://github.com/llvm/llvm-project/blob/9e7a3ee5ff85a6c6838b20734822d658744e9bf3/llvm/lib/DebugInfo/CodeView/LazyRandomTypeCollection.cpp#L186

https://github.com/llvm/llvm-project/pull/164871