[lld] [lld][macho][NFC] Add specific namespace scope for objc symbol names (PR #83618)

[via llvm-commits]

https://github.com/alx32 created https://github.com/llvm/llvm-project/pull/83618

Move symbol names from directly under `objc` scope to `objc::symbol_names`.
Ex: `objc::klass` -> `objc::symbol_names::klass`

>From 9b5a949bdbd9f1efeb4e0a18a0d73aaa3e3c1bfd Mon Sep 17 00:00:00 2001
From: Alex B <alexborcan at meta.com>
Date: Fri, 1 Mar 2024 12:28:50 -0800
Subject: [PATCH] [lld][macho][NFC] Add specific namespace scope for objc
 symbol names

---
 lld/MachO/Driver.cpp     | 4 ++--
 lld/MachO/InputFiles.cpp | 8 ++++----
 lld/MachO/ObjC.h         | 2 ++
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/lld/MachO/Driver.cpp b/lld/MachO/Driver.cpp
index 018ceec97f204a..9edb6b9c60a1fe 100644
--- a/lld/MachO/Driver.cpp
+++ b/lld/MachO/Driver.cpp
@@ -340,7 +340,7 @@ static InputFile *addFile(StringRef path, LoadType loadType,
       }
     } else if (isCommandLineLoad && config->forceLoadObjC) {
       for (const object::Archive::Symbol &sym : file->getArchive().symbols())
-        if (sym.getName().starts_with(objc::klass))
+        if (sym.getName().starts_with(objc::symbol_names::klass))
           file->fetch(sym);
 
       // TODO: no need to look for ObjC sections for a given archive member if
@@ -395,7 +395,7 @@ static InputFile *addFile(StringRef path, LoadType loadType,
     if ((isa<ObjFile>(newFile) || isa<BitcodeFile>(newFile)) && newFile->lazy &&
         config->forceLoadObjC) {
       for (Symbol *sym : newFile->symbols)
-        if (sym && sym->getName().starts_with(objc::klass)) {
+        if (sym && sym->getName().starts_with(objc::symbol_names::klass)) {
           extract(*newFile, "-ObjC");
           break;
         }
diff --git a/lld/MachO/InputFiles.cpp b/lld/MachO/InputFiles.cpp
index 158c3fbf7b0fca..b36d390cc16ade 100644
--- a/lld/MachO/InputFiles.cpp
+++ b/lld/MachO/InputFiles.cpp
@@ -1921,14 +1921,14 @@ DylibFile::DylibFile(const InterfaceFile &interface, DylibFile *umbrella,
     case EncodeKind::ObjectiveCClass:
       // XXX ld64 only creates these symbols when -ObjC is passed in. We may
       // want to emulate that.
-      addSymbol(*symbol, objc::klass + symbol->getName());
-      addSymbol(*symbol, objc::metaclass + symbol->getName());
+      addSymbol(*symbol, objc::symbol_names::klass + symbol->getName());
+      addSymbol(*symbol, objc::symbol_names::metaclass + symbol->getName());
       break;
     case EncodeKind::ObjectiveCClassEHType:
-      addSymbol(*symbol, objc::ehtype + symbol->getName());
+      addSymbol(*symbol, objc::symbol_names::ehtype + symbol->getName());
       break;
     case EncodeKind::ObjectiveCInstanceVariable:
-      addSymbol(*symbol, objc::ivar + symbol->getName());
+      addSymbol(*symbol, objc::symbol_names::ivar + symbol->getName());
       break;
     }
   }
diff --git a/lld/MachO/ObjC.h b/lld/MachO/ObjC.h
index 560c5cc0bc509c..4c65f9a1f78812 100644
--- a/lld/MachO/ObjC.h
+++ b/lld/MachO/ObjC.h
@@ -15,10 +15,12 @@ namespace lld::macho {
 
 namespace objc {
 
+namespace symbol_names {
 constexpr const char klass[] = "_OBJC_CLASS_$_";
 constexpr const char metaclass[] = "_OBJC_METACLASS_$_";
 constexpr const char ehtype[] = "_OBJC_EHTYPE_$_";
 constexpr const char ivar[] = "_OBJC_IVAR_$_";
+} // namespace symbol_names
 
 // Check for duplicate method names within related categories / classes.
 void checkCategories();