[llvm] [yaml2obj] Don't use uninitialized Type (PR #123274)

[Vitaly Buka via llvm-commits]

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@@ -1599,8 +1599,11 @@ void MappingTraits<std::unique_ptr<ELFYAML::Chunk>>::mapping(
     // When the Type string does not have a "SHT_" prefix, we know it is not a
     // description of a regular ELF output section.
     TypeStr = getStringValue(IO, "Type");
-    if (TypeStr.starts_with("SHT_") || isInteger(TypeStr))
+    if (TypeStr.starts_with("SHT_") || isInteger(TypeStr)) {
       IO.mapRequired("Type", Type);
+      if (IO.error())
+        Type = ELF::SHT_NULL;
+    }
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vitalybuka wrote:

On `!IO.error()` mapRequired will set `Type`, it's output arg.

https://github.com/llvm/llvm-project/pull/123274