[lld] [llvm] [MC, COFF] Change how we handle section symbols (PR #96459)

[Fangrui Song via llvm-commits]

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@@ -842,12 +847,21 @@ void WinCOFFWriter::executePostLayoutBinding(MCAssembler &Asm,
     defineSection(static_cast<const MCSectionCOFF &>(Section), Layout);
   }
 
-  if (Mode != DwoOnly)
-    for (const MCSymbol &Symbol : Asm.symbols())
-      // Define non-temporary or temporary static (private-linkage) symbols
-      if (!Symbol.isTemporary() ||
-          cast<MCSymbolCOFF>(Symbol).getClass() == COFF::IMAGE_SYM_CLASS_STATIC)
-        DefineSymbol(Symbol, Asm, Layout);
+  auto isSectionSymbol = [](const MCSymbol &Sym) {
+    return Sym.isInSection() && Sym.getSection().getBeginSymbol() == &Sym;
+  };
+
+  for (const MCSymbol &Sym : Asm.symbols())
+    if (isSectionSymbol(Sym))
+      DefineSymbol(Sym, Asm, Layout);
+  if (Mode == DwoOnly)
+    return;
+  for (const MCSymbol &Sym : Asm.symbols())
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MaskRay wrote:

Split DWARF places `.debug*.dwo` sections in a separate file `a.dwo`. When split DWARF is used, the first loop ensures that the  `.debug*.dwo`   symbols are present in `a.dwo`.

In addition, two loops also allow us to reduce the number of updated tests..

https://github.com/llvm/llvm-project/pull/96459