[llvm] [RISCV] Improvements to .note.gnu.property section. (PR #151436)

[Fangrui Song via llvm-commits]

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@@ -83,29 +86,21 @@ void RISCVTargetStreamer::emitNoteGnuPropertySection(
   OutStreamer.switchSection(NoteSection);
 
   // Emit the note header
-  OutStreamer.emitIntValue(4, 4); // n_namsz
-
-  MCSymbol *const NDescBeginSym = Ctx.createTempSymbol();
-  MCSymbol *const NDescEndSym = Ctx.createTempSymbol();
-  const MCExpr *const NDescSzExpr =
-      MCBinaryExpr::createSub(MCSymbolRefExpr::create(NDescEndSym, Ctx),
-                              MCSymbolRefExpr::create(NDescBeginSym, Ctx), Ctx);
-
-  OutStreamer.emitValue(NDescSzExpr, 4);                    // n_descsz
+  OutStreamer.emitValueToAlignment(NoteAlign);
----------------
MaskRay wrote:

Note sections should be 4- or 8-byte aligned https://groups.google.com/g/generic-abi/c/vT-_QVcckXo/m/Anr17KVUDgAJ

On Linux, NetBSD, Solaris, etc, many systems use 4-byte aligned notes https://reviews.llvm.org/D61296 . `.note.gnu.property`, as a newer section, uses 8-byte alignment in ELFCLASS64.

https://github.com/llvm/llvm-project/pull/151436