[llvm] [NFCI][Globals]For GlobalObjects, add updateSectionPrefix and change setSectionPrefix to handle empty strings (PR #158460)

[Teresa Johnson via llvm-commits]

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@@ -289,11 +289,28 @@ void GlobalObject::setSection(StringRef S) {
 }
 
 void GlobalObject::setSectionPrefix(StringRef Prefix) {
+  if (Prefix.empty()) {
+    setMetadata(LLVMContext::MD_section_prefix, nullptr);
+    return;
+  }
   MDBuilder MDB(getContext());
   setMetadata(LLVMContext::MD_section_prefix,
               MDB.createGlobalObjectSectionPrefix(Prefix));
 }
 
+bool GlobalObject::updateSectionPrefix(StringRef Prefix) {
+  auto MD = getMetadata(LLVMContext::MD_section_prefix);
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teresajohnson wrote:

Use getSectionPrefix instead? It does some assertion checking that could be useful.

Also, does it make sense to just make this the default behavior of setSectionPrefix?

https://github.com/llvm/llvm-project/pull/158460