Reapply "Store token literal data in PCH (ROOT-6794)."

interpreter/llvm-project/clang/include/clang/Serialization/ASTReader.h

@@ -800,6 +800,9 @@ class ASTReader
   /// files.
   llvm::DenseSet<LoadedMacroInfo> LoadedUndefs;
 
+  /// \Token literal data loaded and owned by us.
+  std::vector<std::string *> TokenLiteralDataLoaded;
+
   /// A vector containing submodules that have already been loaded.
   ///
   /// This vector is indexed by the Submodule ID (-1). NULL submodule entries

interpreter/llvm-project/clang/lib/Serialization/ASTReader.cpp

@@ -2135,6 +2135,14 @@ Token ASTReader::ReadToken(ModuleFile &M, const RecordDataImpl &Record,
     if (IdentifierInfo *II = getLocalIdentifier(M, Record[Idx++]))
       Tok.setIdentifierInfo(II);
   }
+
+  if (Tok.isLiteral()) {
+    const RecordData& RD = reinterpret_cast<const RecordData&>(Record);
+    std::string* Lit = new std::string(ReadString(RD, Idx));
+    TokenLiteralDataLoaded.push_back(Lit);
+    Tok.setLiteralData(Lit->c_str());
+  }
+
   return Tok;
 }
 
@@ -11268,6 +11276,9 @@ ASTReader::ASTReader(Preprocessor &PP, ModuleCache &ModCache,
 ASTReader::~ASTReader() {
   if (OwnsDeserializationListener)
     delete DeserializationListener;
+  for (auto PStr: TokenLiteralDataLoaded) {
+     delete PStr;
+  }
 }
 
 IdentifierResolver &ASTReader::getIdResolver() {

interpreter/llvm-project/clang/lib/Serialization/ASTWriter.cpp

@@ -5322,6 +5322,9 @@ void ASTWriter::AddToken(const Token &Tok, RecordDataImpl &Record) {
     // is needed.
     AddIdentifierRef(Tok.getIdentifierInfo(), Record);
   }
+
+  if (Tok.isLiteral())
+    AddString(StringRef(Tok.getLiteralData(), Tok.getLength()), Record);
 }
 
 void ASTWriter::AddString(StringRef Str, RecordDataImpl &Record) {

interpreter/llvm-project/llvm-project.tag

@@ -1 +1 @@
-ROOT-llvm22-20260827-01
+ROOT-llvm22-20260902-01