[clang] [llvm] [PGO][GlobalValue][LTO]In GlobalValues::getGlobalIdentifier, use semicolon as delimiter for local-linkage varibles. (PR #74008)

[Ellis Hoag via cfe-commits]

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@@ -300,12 +316,8 @@ getIRPGONameForGlobalObject(const GlobalObject &GO,
                             GlobalValue::LinkageTypes Linkage,
                             StringRef FileName) {
   SmallString<64> Name;
-  if (llvm::GlobalValue::isLocalLinkage(Linkage)) {
-    Name.append(FileName.empty() ? "<unknown>" : FileName);
-    Name.append(";");
-  }
   Mangler().getNameWithPrefix(Name, &GO, /*CannotUsePrivateLabel=*/true);
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ellishg wrote:

> Was PGO broken in general before D156569? Or is this specific to -symbol-ordering-file and -order_file?

It wasn't broken in general, but it's needed to get `-order_file` working correctly.

> Also, it looks like some of the main changes here by the mangler for objective C are to strip the "\01" prefix. Is this different than the support to remove the '\1' mangling escape in getGlobalIdentifier()?

I think both remove the `\01` prefix. But the mangler might also prepend `_`/`l_` depending on the linkage, and `getGlobalIdentifier()` does not do this.

https://github.com/llvm/llvm-project/pull/74008