From d1f13d2871a815b253b151edf6d3f5d544ea10e2 Mon Sep 17 00:00:00 2001
From: Leonardo de Moura <leonardo@microsoft.com>
Date: Fri, 14 Aug 2015 18:22:46 -0700
Subject: [PATCH] perf(library/module): skip checksum if trust level is very
 high

---
 src/library/module.cpp | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/library/module.cpp b/src/library/module.cpp
index ee8ae55e9..4ddba048e 100644
--- a/src/library/module.cpp
+++ b/src/library/module.cpp
@@ -369,9 +369,11 @@ struct import_modules_fn {
             std::vector<char> code(code_size);
             d1.read(code);
 
-            unsigned computed_hash = hash(code_size, [&](unsigned i) { return code[i]; });
-            if (claimed_hash != computed_hash)
-                throw exception(sstream() << "file '" << fname << "' has been corrupted, checksum mismatch");
+            if (m_senv.env().trust_lvl() <= LEAN_BELIEVER_TRUST_LEVEL) {
+                unsigned computed_hash = hash(code_size, [&](unsigned i) { return code[i]; });
+                if (claimed_hash != computed_hash)
+                    throw exception(sstream() << "file '" << fname << "' has been corrupted, checksum mismatch");
+            }
 
             module_info_ptr r = std::make_shared<module_info>();
             r->m_fname        = fname;