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

[Fangrui Song via llvm-commits]

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@@ -585,6 +587,34 @@ SmallVector<SectionCommand *, 0> ScriptParser::readOverlay() {
   return v;
 }
 
+SectionClassDesc *ScriptParser::readSectionClassDescription() {
+  StringRef name = readSectionClassName();
+  SectionClassDesc *desc = make<SectionClassDesc>(name);
+  if (!script->sectionClasses.insert({name, desc}).second)
+    setError("section class '" + name + "' already defined");
+  expect("{");
+  while (!errorCount() && !consume("}")) {
+    StringRef tok = next();
+    if (tok == "(" || tok == ")") {
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MaskRay wrote:

`tok == ")"` is to work around the limitation of our lexer. Does it need a test similar to `missing-filename-pattern.lds`?

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