[llvm] [TextAPI] Add option to filter out unsupported/unknown/invalid targets (PR #195161)

[Zixu Wang via llvm-commits]

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@@ -313,6 +314,12 @@ template <> struct MappingTraits<UndefinedSection> {
 template <> struct MappingTraits<SymbolSection> {
   static void mapping(IO &IO, SymbolSection &Section) {
     IO.mapRequired("targets", Section.Targets);
+    // With SkipUnknownTriples, ScalarTraits of Target accepts unknown
+    // arch/platform scalars without erroring, leaving invalid Targets in the
+    // vector. Drop them so downstream code only sees valid Targets.
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zixu-w wrote:

I was thinking we don't erase in the YAML mappings, but the wrapper container filters them out when accessing (iterating, `empty()`, etc.)

https://github.com/llvm/llvm-project/pull/195161