From c8bb2371ebf25ab78abde84e3c5742f9844a74b7 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Thu, 23 Jul 2015 23:11:08 +0200
Subject: Optimize empty sets

This reduces the number of Bindings allocations by about 10%.
---
 src/libexpr/eval.cc | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'src/libexpr/eval.cc')

diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 044256112d50..14169d85735e 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -281,6 +281,10 @@ EvalState::EvalState(const Strings & _searchPath)
     for (auto & i : paths) addToSearchPath(i);
     addToSearchPath("nix=" + settings.nixDataDir + "/nix/corepkgs");
 
+    clearValue(vEmptySet);
+    vEmptySet.type = tAttrs;
+    vEmptySet.attrs = allocBindings(0);
+
     createBaseEnv();
 }
 
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