[MC] Don't evaluate name of unnamed symbols (llvm#95021)

There's only one way to create unnamed symbols (createTempSymbol).
Previously, the name was evaluated unconditionally, but often
unnecessarily. Avoid this.

Also the parameter names in the header were wrong, fix these.

llvm/include/llvm/MC/MCContext.h

@@ -371,7 +371,7 @@ class MCContext {
                     std::function<void(SMDiagnostic &, const SourceMgr *)>);
 
   MCSymbol *createSymbolImpl(const StringMapEntry<bool> *Name,
-                             bool CanBeUnnamed);
+                             bool IsTemporary);
   MCSymbol *createSymbol(StringRef Name, bool AlwaysAddSuffix,
                          bool IsTemporary);
 

llvm/lib/MC/MCContext.cpp

@@ -264,13 +264,9 @@ MCSymbol *MCContext::createSymbolImpl(const StringMapEntry<bool> *Name,
 }
 
 MCSymbol *MCContext::createSymbol(StringRef Name, bool AlwaysAddSuffix,
-                                  bool CanBeUnnamed) {
-  if (CanBeUnnamed && !UseNamesOnTempLabels)
-    return createSymbolImpl(nullptr, true);
-
+                                  bool IsTemporary) {
   // Determine whether this is a user written assembler temporary or normal
   // label, if used.
-  bool IsTemporary = CanBeUnnamed;
   if (AllowTemporaryLabels && !IsTemporary)
     IsTemporary = Name.starts_with(MAI->getPrivateGlobalPrefix());
 
@@ -298,6 +294,9 @@ MCSymbol *MCContext::createSymbol(StringRef Name, bool AlwaysAddSuffix,
 }
 
 MCSymbol *MCContext::createTempSymbol(const Twine &Name, bool AlwaysAddSuffix) {
+  if (!UseNamesOnTempLabels)
+    return createSymbolImpl(nullptr, /*IsTemporary=*/true);
+
   SmallString<128> NameSV;
   raw_svector_ostream(NameSV) << MAI->getPrivateGlobalPrefix() << Name;
   return createSymbol(NameSV, AlwaysAddSuffix, true);