[clang] [clang][NFC] Preprocessor only needs const LangOptions (PR #66874)

[Timm Baeder via cfe-commits]

https://github.com/tbaederr created https://github.com/llvm/llvm-project/pull/66874

NFC but requesting review since something outside of clang or downstream might break?

>From 81573459077ce79d65a60310be12f01db4371e9c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbaeder at redhat.com>
Date: Wed, 20 Sep 2023 10:38:01 +0200
Subject: [PATCH] [clang][NFC] Preprocessor only needs const LangOptions

---
 clang/include/clang/Lex/Preprocessor.h | 7 ++++---
 clang/lib/Lex/Preprocessor.cpp         | 2 +-
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/clang/include/clang/Lex/Preprocessor.h b/clang/include/clang/Lex/Preprocessor.h
index bc1d94a61508d8d..22996ceede42183 100644
--- a/clang/include/clang/Lex/Preprocessor.h
+++ b/clang/include/clang/Lex/Preprocessor.h
@@ -132,7 +132,7 @@ class Preprocessor {
   llvm::unique_function<void(const clang::Token &)> OnToken;
   std::shared_ptr<PreprocessorOptions> PPOpts;
   DiagnosticsEngine        *Diags;
-  LangOptions       &LangOpts;
+  const LangOptions &LangOpts;
   const TargetInfo *Target = nullptr;
   const TargetInfo *AuxTarget = nullptr;
   FileManager       &FileMgr;
@@ -1158,8 +1158,9 @@ class Preprocessor {
 
 public:
   Preprocessor(std::shared_ptr<PreprocessorOptions> PPOpts,
-               DiagnosticsEngine &diags, LangOptions &opts, SourceManager &SM,
-               HeaderSearch &Headers, ModuleLoader &TheModuleLoader,
+               DiagnosticsEngine &diags, const LangOptions &LangOpts,
+               SourceManager &SM, HeaderSearch &Headers,
+               ModuleLoader &TheModuleLoader,
                IdentifierInfoLookup *IILookup = nullptr,
                bool OwnsHeaderSearch = false,
                TranslationUnitKind TUKind = TU_Complete);
diff --git a/clang/lib/Lex/Preprocessor.cpp b/clang/lib/Lex/Preprocessor.cpp
index 8de78a13930ed62..078119f6685cd8c 100644
--- a/clang/lib/Lex/Preprocessor.cpp
+++ b/clang/lib/Lex/Preprocessor.cpp
@@ -77,7 +77,7 @@ LLVM_INSTANTIATE_REGISTRY(PragmaHandlerRegistry)
 ExternalPreprocessorSource::~ExternalPreprocessorSource() = default;
 
 Preprocessor::Preprocessor(std::shared_ptr<PreprocessorOptions> PPOpts,
-                           DiagnosticsEngine &diags, LangOptions &opts,
+                           DiagnosticsEngine &diags, const LangOptions &opts,
                            SourceManager &SM, HeaderSearch &Headers,
                            ModuleLoader &TheModuleLoader,
                            IdentifierInfoLookup *IILookup, bool OwnsHeaders,