Add native comparison of configured targets

... and use it when normalizing the origins of actions. For this
task, any well-defined linear order is sufficient. Using a native
comparision (rather than comparing the canonical serialisation)
significantly speeds up that normalisation process, as the assumption
that it would be rare that an action has more than one origin turned
out to be false. In fact, we have seeen cases where this sorting
used to take several seconds before this change, so that this change
reduced analysis time by more than a factor of 5.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/buildtool/build_engine/expression/configuration.hpp b/src/buildtool/build_engine/expression/configuration.hpp
index ec3fde66..dadb71d2 100644
--- a/src/buildtool/build_engine/expression/configuration.hpp
+++ b/src/buildtool/build_engine/expression/configuration.hpp
@@ -16,6 +16,7 @@
 #define INCLUDED_SRC_BUILDTOOL_BUILD_ENGINE_EXPRESSION_CONFIGURATION_HPP
 
 #include <algorithm>
+#include <compare>
 #include <cstddef>
 #include <functional>
 #include <optional>
@@ -92,6 +93,10 @@ class Configuration {
         return expr_ == other.expr_;
     }
 
+    [[nodiscard]] auto operator<(const Configuration& other) const -> bool {
+        return expr_->ToHash() < other.expr_->ToHash();
+    }
+
     [[nodiscard]] auto hash() const noexcept -> std::size_t {
         return std::hash<ExpressionPtr>{}(expr_);
     }