[llvm] [RISCV] Let -data-sections also work on sbss/sdata sections (PR #87040)

[Sam Elliott via llvm-commits]

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@@ -104,10 +104,34 @@ bool RISCVELFTargetObjectFile::isGlobalInSmallSection(
 MCSection *RISCVELFTargetObjectFile::SelectSectionForGlobal(
     const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
   // Handle Small Section classification here.
-  if (Kind.isBSS() && isGlobalInSmallSection(GO, TM))
-    return SmallBSSSection;
-  if (Kind.isData() && isGlobalInSmallSection(GO, TM))
-    return SmallDataSection;
+  if (isGlobalInSmallSection(GO, TM)) {
+    // Emit to an unique sdata/sbss section when -fdata-section is set.
+    // However, if a symbol has an explicit sdata/sbss section, place it in that
+    // section.
+    bool EmitUniquedSection = TM.getDataSections() && !GO->hasSection();
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lenary wrote:

I think this is still wrong, and that the `!GO->hasSection()` check needs to take priority over the `isGlobalInSmallSection` - I noted in the test where I think things will still go wrong.

https://github.com/llvm/llvm-project/pull/87040