[lld] [llvm] [lld][AArch64][Build Attributes] Add support for converting AArch64 Build Attributes to GNU Properties (PR #131990)

[Peter Smith via llvm-commits]

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@@ -207,6 +209,51 @@ static void updateSupportedARMFeatures(Ctx &ctx,
   ctx.arg.armHasThumb2ISA |= thumb && *thumb >= ARMBuildAttrs::AllowThumb32;
 }
 
+struct KnownAArch64BuildAttrSubsections {
+  struct PauthSubSection {
+    unsigned tagPlatform = 0;
+    unsigned tagSchema = 0;
+  } pauth;
+  struct FAndBSubSection {
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smithp35 wrote:

I don't think you need to directly represent each tag here. We know that the and features subsection is meant to 1:1 map to the .note.gnu.properties section so we can record this directly.

This could be represented as `uint32_t andFeatures;`
When reading `TAG_FEATURE_BTI` and friends in extractBuildAttributes Subsections then the value could be orred into the appropriate place.

This would also simplify any comparison with feature and bits from GNU properties.


https://github.com/llvm/llvm-project/pull/131990