[lld] [LLD] Add CLASS syntax to SECTIONS (PR #95323)

[Fangrui Song via llvm-commits]

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@@ -413,6 +422,11 @@ class LinkerScript final {
     PotentialSpillSection *tail;
   };
   llvm::DenseMap<InputSectionBase *, PotentialSpillList> potentialSpillLists;
+
+  // Named lists of input sections that can be collectively referenced in output
+  // section descriptions. Multiple references allow for sections to spill from
+  // one output section to another.
+  llvm::StringMap<SectionClassDesc *> sectionClasses;
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MaskRay wrote:

`DenseMap<CachedHashStringRef, >` or `<StringRef, >`

This header otherwise doesn't use StringMap

https://github.com/llvm/llvm-project/pull/95323