[llvm] [AsmPrinter][ELF] Support profile-guided section prefix for jump tables' (read-only) data sections (PR #122215)

[Snehasish Kumar via llvm-commits]

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@@ -669,7 +671,15 @@ getELFSectionNameForGlobal(const GlobalObject *GO, SectionKind Kind,
 
   bool HasPrefix = false;
   if (const auto *F = dyn_cast<Function>(GO)) {
-    if (std::optional<StringRef> Prefix = F->getSectionPrefix()) {
+    // Jump table hotness takes precedence over its enclosing function's hotness
+    // if both are available.
+    if (JTE) {
+      if (JTE->Hotness == MachineFunctionDataHotness::Hot) {
+        raw_svector_ostream(Name) << ".hot";
+      } else if (JTE->Hotness == MachineFunctionDataHotness::Cold) {
+        raw_svector_ostream(Name) << ".unlikely";
+      }
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snehasish wrote:

What will happen to the case where `JTE->Hotness == MachineFunctionDataHotness::Unknown`? I think the behaviour we want is to fall back to the section prefix. Can you add a test if you agree?

https://github.com/llvm/llvm-project/pull/122215