[lldb][Mangled] Add API to force re-demangling a Mangled object (llvm#131836)

Add version of GetDemangledName that will force re-demangling. This is required because LLDB will SetDemangledName without going through the demangler. So we need a way to force demangling to set the m_demangled_info member when we need it.

llvm#131836

Author: Michael137

lldb/include/lldb/Core/Mangled.h

@@ -278,6 +278,12 @@ class Mangled {
   void Encode(DataEncoder &encoder, ConstStringTable &strtab) const;
 
 private:
+  /// If \c force is \c false, this function will re-use the previously
+  /// demangled name (if any). If \c force is \c true (or the mangled name
+  /// on this object was not previously demangled), demangle and cache the
+  /// name.
+  ConstString GetDemangledNameImpl(bool force) const;
+
   /// The mangled version of the name.
   ConstString m_mangled;
 

lldb/source/Core/Mangled.cpp

@@ -265,19 +265,24 @@ bool Mangled::GetRichManglingInfo(RichManglingContext &context,
   llvm_unreachable("Fully covered switch above!");
 }
 
+ConstString Mangled::GetDemangledName() const {
+  return GetDemangledNameImpl(/*force=*/false);
+}
+
 // Generate the demangled name on demand using this accessor. Code in this
 // class will need to use this accessor if it wishes to decode the demangled
 // name. The result is cached and will be kept until a new string value is
 // supplied to this object, or until the end of the object's lifetime.
-ConstString Mangled::GetDemangledName() const {
+ConstString Mangled::GetDemangledNameImpl(bool force) const {
   if (!m_mangled)
     return m_demangled;
 
   // Re-use previously demangled names.
-  if (!m_demangled.IsNull())
+  if (!force && !m_demangled.IsNull())
     return m_demangled;
 
-  if (m_mangled.GetMangledCounterpart(m_demangled) && !m_demangled.IsNull())
+  if (!force && m_mangled.GetMangledCounterpart(m_demangled) &&
+      !m_demangled.IsNull())
     return m_demangled;
 
   // We didn't already mangle this name, demangle it and if all goes well