diff --git a/lldb/source/Core/DemangledNameInfo.cpp b/lldb/source/Core/DemangledNameInfo.cpp
index 00227f02bbff8..76f8987c5149c 100644
--- a/lldb/source/Core/DemangledNameInfo.cpp
+++ b/lldb/source/Core/DemangledNameInfo.cpp
@@ -111,6 +111,11 @@ void TrackingOutputBuffer::finalizeEnd() {
   if (NameInfo.ScopeRange.first > NameInfo.ScopeRange.second)
     NameInfo.ScopeRange.second = NameInfo.ScopeRange.first;
   NameInfo.BasenameRange.first = NameInfo.ScopeRange.second;
+
+  // We call anything past the FunctionEncoding the "suffix".
+  // In practice this would be nodes like `DotSuffix` that wrap
+  // a FunctionEncoding.
+  NameInfo.SuffixRange.first = getCurrentPosition();
 }
 
 ScopedOverride<unsigned> TrackingOutputBuffer::enterFunctionTypePrinting() {
@@ -138,6 +143,9 @@ void TrackingOutputBuffer::printLeft(const Node &N) {
   default:
     OutputBuffer::printLeft(N);
   }
+
+  // Keep updating suffix until we reach the end.
+  NameInfo.SuffixRange.second = getCurrentPosition();
 }
 
 void TrackingOutputBuffer::printRight(const Node &N) {
@@ -151,6 +159,9 @@ void TrackingOutputBuffer::printRight(const Node &N) {
   default:
     OutputBuffer::printRight(N);
   }
+
+  // Keep updating suffix until we reach the end.
+  NameInfo.SuffixRange.second = getCurrentPosition();
 }
 
 void TrackingOutputBuffer::printLeftImpl(const FunctionType &N) {
diff --git a/lldb/source/Core/Mangled.cpp b/lldb/source/Core/Mangled.cpp
index 3663f430111c2..ce4db4e0daa8b 100644
--- a/lldb/source/Core/Mangled.cpp
+++ b/lldb/source/Core/Mangled.cpp
@@ -172,9 +172,6 @@ GetItaniumDemangledStr(const char *M) {
 
     TrackingOutputBuffer OB(demangled_cstr, demangled_size);
     demangled_cstr = ipd.finishDemangle(&OB);
-    // TODO: we should set the SuffixRange inside the TrackingOutputBuffer.
-    OB.NameInfo.SuffixRange.first = OB.NameInfo.QualifiersRange.second;
-    OB.NameInfo.SuffixRange.second = std::string_view(OB).size();
     info = std::move(OB.NameInfo);
 
     assert(demangled_cstr &&
diff --git a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
index 3bc870810dc81..3118ff151d1cf 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
@@ -392,13 +392,16 @@ GetDemangledScope(const SymbolContext &sc) {
   return CPlusPlusLanguage::GetDemangledScope(demangled_name, info);
 }
 
-/// Handles anything printed after the FunctionEncoding ItaniumDemangle
-/// node. Most notably the DotSuffix node.
-///
-/// FIXME: the suffix should also have an associated
-/// CPlusPlusLanguage::GetDemangledFunctionSuffix
-/// once we start setting the `DemangledNameInfo::SuffixRange`
-/// from inside the `TrackingOutputBuffer`.
+llvm::Expected<llvm::StringRef>
+CPlusPlusLanguage::GetDemangledFunctionSuffix(llvm::StringRef demangled,
+                                              const DemangledNameInfo &info) {
+  if (!info.hasSuffix())
+    return llvm::createStringError("Suffix range for '%s' is invalid.",
+                                   demangled.data());
+
+  return demangled.slice(info.SuffixRange.first, info.SuffixRange.second);
+}
+
 static llvm::Expected<llvm::StringRef>
 GetDemangledFunctionSuffix(const SymbolContext &sc) {
   auto info_or_err = GetAndValidateInfo(sc);
@@ -407,11 +410,7 @@ GetDemangledFunctionSuffix(const SymbolContext &sc) {
 
   auto [demangled_name, info] = *info_or_err;
 
-  if (!info.hasSuffix())
-    return llvm::createStringError("Suffix range for '%s' is invalid.",
-                                   demangled_name.data());
-
-  return demangled_name.slice(info.SuffixRange.first, info.SuffixRange.second);
+  return CPlusPlusLanguage::GetDemangledFunctionSuffix(demangled_name, info);
 }
 
 llvm::Expected<llvm::StringRef>
@@ -2424,7 +2423,7 @@ bool CPlusPlusLanguage::HandleFrameFormatVariable(
     return true;
   }
   case FormatEntity::Entry::Type::FunctionSuffix: {
-    auto suffix_or_err = GetDemangledFunctionSuffix(sc);
+    auto suffix_or_err = ::GetDemangledFunctionSuffix(sc);
     if (!suffix_or_err) {
       LLDB_LOG_ERROR(
           GetLog(LLDBLog::Language), suffix_or_err.takeError(),
diff --git a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.h b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.h
index 4f449f11257a6..4a30299dd2658 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.h
+++ b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.h
@@ -138,6 +138,10 @@ class CPlusPlusLanguage : public Language {
   GetDemangledFunctionArguments(llvm::StringRef demangled,
                                 const DemangledNameInfo &info);
 
+  static llvm::Expected<llvm::StringRef>
+  GetDemangledFunctionSuffix(llvm::StringRef demangled,
+                             const DemangledNameInfo &info);
+
   // Extract C++ context and identifier from a string using heuristic matching
   // (as opposed to
   // CPlusPlusLanguage::CxxMethodName which has to have a fully qualified C++
diff --git a/lldb/unittests/Core/MangledTest.cpp b/lldb/unittests/Core/MangledTest.cpp
index a6e6e75fde145..cbc0c5d951b99 100644
--- a/lldb/unittests/Core/MangledTest.cpp
+++ b/lldb/unittests/Core/MangledTest.cpp
@@ -889,10 +889,10 @@ TEST_P(DemanglingInfoCorrectnessTestFixutre, Correctness) {
   EXPECT_THAT_EXPECTED(qualifiers, llvm::Succeeded());
   reconstructed_name += *qualifiers;
 
-  // TODO: should retrieve suffix using the plugin too.
-  auto suffix = tracked_name.slice(OB->NameInfo.QualifiersRange.second,
-                                   llvm::StringRef::npos);
-  reconstructed_name += suffix;
+  auto suffix =
+      CPlusPlusLanguage::GetDemangledFunctionSuffix(tracked_name, OB->NameInfo);
+  EXPECT_THAT_EXPECTED(suffix, llvm::Succeeded());
+  reconstructed_name += *suffix;
 
   EXPECT_EQ(reconstructed_name, demangled);
 }