diff --git a/clang-tools-extra/include-cleaner/include/clang-include-cleaner/Analysis.h b/clang-tools-extra/include-cleaner/include/clang-include-cleaner/Analysis.h
index 66916a52046cb..6d764c65a11b2 100644
--- a/clang-tools-extra/include-cleaner/include/clang-include-cleaner/Analysis.h
+++ b/clang-tools-extra/include-cleaner/include/clang-include-cleaner/Analysis.h
@@ -67,7 +67,7 @@ struct AnalysisResults {
 AnalysisResults analyze(llvm::ArrayRef<Decl *> ASTRoots,
                         llvm::ArrayRef<SymbolReference> MacroRefs,
                         const Includes &I, const PragmaIncludes *PI,
-                        const SourceManager &SM, HeaderSearch &HS);
+                        const SourceManager &SM, const HeaderSearch &HS);
 
 /// Removes unused includes and inserts missing ones in the main file.
 /// Returns the modified main-file code.
@@ -75,7 +75,7 @@ AnalysisResults analyze(llvm::ArrayRef<Decl *> ASTRoots,
 std::string fixIncludes(const AnalysisResults &Results, llvm::StringRef Code,
                         const format::FormatStyle &IncludeStyle);
 
-std::string spellHeader(const Header &H, HeaderSearch &HS,
+std::string spellHeader(const Header &H, const HeaderSearch &HS,
                         const FileEntry *Main);
 
 /// Gets all the providers for a symbol by traversing each location.
diff --git a/clang-tools-extra/include-cleaner/lib/Analysis.cpp b/clang-tools-extra/include-cleaner/lib/Analysis.cpp
index 84f1f4cc2cf54..bf50e064e9811 100644
--- a/clang-tools-extra/include-cleaner/lib/Analysis.cpp
+++ b/clang-tools-extra/include-cleaner/lib/Analysis.cpp
@@ -53,7 +53,7 @@ void walkUsed(llvm::ArrayRef<Decl *> ASTRoots,
   }
 }
 
-std::string spellHeader(const Header &H, HeaderSearch &HS,
+std::string spellHeader(const Header &H, const HeaderSearch &HS,
                         const FileEntry *Main) {
   switch (H.kind()) {
   case Header::Physical: {
@@ -73,7 +73,7 @@ std::string spellHeader(const Header &H, HeaderSearch &HS,
 AnalysisResults analyze(llvm::ArrayRef<Decl *> ASTRoots,
                         llvm::ArrayRef<SymbolReference> MacroRefs,
                         const Includes &Inc, const PragmaIncludes *PI,
-                        const SourceManager &SM, HeaderSearch &HS) {
+                        const SourceManager &SM, const HeaderSearch &HS) {
   const FileEntry *MainFile = SM.getFileEntryForID(SM.getMainFileID());
   llvm::DenseSet<const Include *> Used;
   llvm::StringSet<> Missing;
diff --git a/clang-tools-extra/include-cleaner/lib/AnalysisInternal.h b/clang-tools-extra/include-cleaner/lib/AnalysisInternal.h
index 6bfed91b584b3..cd796c2da7b80 100644
--- a/clang-tools-extra/include-cleaner/lib/AnalysisInternal.h
+++ b/clang-tools-extra/include-cleaner/lib/AnalysisInternal.h
@@ -63,7 +63,7 @@ std::vector<Hinted<SymbolLocation>> locateSymbol(const Symbol &S);
 void writeHTMLReport(FileID File, const Includes &,
                      llvm::ArrayRef<Decl *> Roots,
                      llvm::ArrayRef<SymbolReference> MacroRefs, ASTContext &Ctx,
-                     HeaderSearch &HS, PragmaIncludes *PI,
+                     const HeaderSearch &HS, PragmaIncludes *PI,
                      llvm::raw_ostream &OS);
 
 } // namespace include_cleaner
diff --git a/clang-tools-extra/include-cleaner/lib/HTMLReport.cpp b/clang-tools-extra/include-cleaner/lib/HTMLReport.cpp
index c1d1982d4f487..65b82973c4290 100644
--- a/clang-tools-extra/include-cleaner/lib/HTMLReport.cpp
+++ b/clang-tools-extra/include-cleaner/lib/HTMLReport.cpp
@@ -134,7 +134,7 @@ class Reporter {
   llvm::raw_ostream &OS;
   const ASTContext &Ctx;
   const SourceManager &SM;
-  HeaderSearch &HS;
+  const HeaderSearch &HS;
   const include_cleaner::Includes &Includes;
   const PragmaIncludes *PI;
   FileID MainFile;
@@ -208,7 +208,7 @@ class Reporter {
   }
 
 public:
-  Reporter(llvm::raw_ostream &OS, ASTContext &Ctx, HeaderSearch &HS,
+  Reporter(llvm::raw_ostream &OS, ASTContext &Ctx, const HeaderSearch &HS,
            const include_cleaner::Includes &Includes, const PragmaIncludes *PI,
            FileID MainFile)
       : OS(OS), Ctx(Ctx), SM(Ctx.getSourceManager()), HS(HS),
@@ -513,7 +513,7 @@ class Reporter {
 void writeHTMLReport(FileID File, const include_cleaner::Includes &Includes,
                      llvm::ArrayRef<Decl *> Roots,
                      llvm::ArrayRef<SymbolReference> MacroRefs, ASTContext &Ctx,
-                     HeaderSearch &HS, PragmaIncludes *PI,
+                     const HeaderSearch &HS, PragmaIncludes *PI,
                      llvm::raw_ostream &OS) {
   Reporter R(OS, Ctx, HS, Includes, PI, File);
   const auto& SM = Ctx.getSourceManager();
diff --git a/clang-tools-extra/include-cleaner/lib/Record.cpp b/clang-tools-extra/include-cleaner/lib/Record.cpp
index ff29fda8663b9..113a69c7fbee7 100644
--- a/clang-tools-extra/include-cleaner/lib/Record.cpp
+++ b/clang-tools-extra/include-cleaner/lib/Record.cpp
@@ -305,7 +305,7 @@ class PragmaIncludes::RecordPragma : public PPCallbacks, public CommentHandler {
 
   bool InMainFile = false;
   const SourceManager &SM;
-  HeaderSearch &HeaderInfo;
+  const HeaderSearch &HeaderInfo;
   PragmaIncludes *Out;
   llvm::BumpPtrAllocator Arena;
   /// Intern table for strings. Contents are on the arena.