4 files changed, 11 insertions, 26 deletions
diff --git a/src/buildtool/compatibility/compatibility.hpp b/src/buildtool/compatibility/compatibility.hpp
index e2eecb11..2073ad52 100644
--- a/src/buildtool/compatibility/compatibility.hpp
+++ b/src/buildtool/compatibility/compatibility.hpp
@@ -39,9 +39,6 @@ class Compatibility {
     }
     static void SetCompatible(bool value = true) noexcept {
         Instance().compatible_ = value;
-        auto const hasher_type = value ? HashFunction::JustHash::Compatible
-                                       : HashFunction::JustHash::Native;
-        HashFunction::Instance().SetHashType(hasher_type);
     }
 
     [[nodiscard]] static auto RegisterGitEntry(std::string const& git_hash,
diff --git a/src/buildtool/crypto/hash_function.hpp b/src/buildtool/crypto/hash_function.hpp
index 6932a077..8d932016 100644
--- a/src/buildtool/crypto/hash_function.hpp
+++ b/src/buildtool/crypto/hash_function.hpp
@@ -33,22 +33,18 @@ class HashFunction {
         Compatible  ///< SHA256 for all hashes.
     };
 
-    static constexpr auto kDefaultType = JustHash::Native;
-
-    explicit HashFunction(JustHash type) noexcept : type_{type} {}
+    explicit HashFunction(JustHash type) noexcept : type_{type} {
+        static_assert(
+            sizeof(HashFunction) <= sizeof(void*),
+            "HashFunction is passed and stored by value. If the "
+            "class is extended so that its size exceeds the size of a pointer, "
+            "the way how HashFunction is passed and stored must be changed.");
+    }
 
     [[nodiscard]] auto GetHashType() const noexcept -> JustHash {
         return type_;
     }
 
-    [[nodiscard]] static auto Instance() noexcept -> HashFunction& {
-        static HashFunction instance{kDefaultType};
-        return instance;
-    }
-
-    /// \brief Set globally used hash type.
-    void SetHashType(JustHash type) noexcept { type_ = type; }
-
     /// \brief Compute a plain hash.
     [[nodiscard]] auto ComputeHash(std::string const& data) const noexcept
         -> Hasher::HashDigest {
@@ -92,7 +88,7 @@ class HashFunction {
     }
 
   private:
-    JustHash type_ = kDefaultType;
+    JustHash const type_;
 
     [[nodiscard]] auto ComputeTaggedHash(
         std::string const& data,
diff --git a/src/buildtool/main/main.cpp b/src/buildtool/main/main.cpp
index 9f10b8bc..b089e321 100644
--- a/src/buildtool/main/main.cpp
+++ b/src/buildtool/main/main.cpp
@@ -259,12 +259,6 @@ void SetupExecutionServiceConfig(ServiceArguments const& args) {
     }
 }
 
-void SetupHashFunction() {
-    HashFunction::Instance().SetHashType(
-        Compatibility::IsCompatible() ? HashFunction::JustHash::Compatible
-                                      : HashFunction::JustHash::Native);
-}
-
 void SetupFileChunker() {
     FileChunker::Initialize();
 }
@@ -797,7 +791,6 @@ auto main(int argc, char* argv[]) -> int {
          */
         GitContext::Create();
 
-        SetupHashFunction();
         SetupFileChunker();
 
         if (arguments.cmd == SubCommand::kGc) {
diff --git a/src/buildtool/storage/config.hpp b/src/buildtool/storage/config.hpp
index 5861977e..56274c02 100644
--- a/src/buildtool/storage/config.hpp
+++ b/src/buildtool/storage/config.hpp
@@ -222,10 +222,9 @@ class StorageConfig::Builder final {
             }
         }
 
-        auto hash_function = default_config.hash_function;
-        if (hash_type_.has_value()) {
-            hash_function = HashFunction{*hash_type_};
-        }
+        auto const hash_function = hash_type_.has_value()
+                                       ? HashFunction{*hash_type_}
+                                       : default_config.hash_function;
 
         // Hash the execution backend description
         auto backend_description_id = default_config.backend_description_id;