[compiler-rt] r212704 - [msan] Switch chained origins hash to murmur2.
Evgeniy Stepanov
eugeni.stepanov at gmail.com
Thu Jul 10 04:02:34 PDT 2014
Author: eugenis
Date: Thu Jul 10 06:02:33 2014
New Revision: 212704
URL: http://llvm.org/viewvc/llvm-project?rev=212704&view=rev
Log:
[msan] Switch chained origins hash to murmur2.
Modified:
compiler-rt/trunk/lib/msan/msan_chained_origin_depot.cc
Modified: compiler-rt/trunk/lib/msan/msan_chained_origin_depot.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/msan/msan_chained_origin_depot.cc?rev=212704&r1=212703&r2=212704&view=diff
==============================================================================
--- compiler-rt/trunk/lib/msan/msan_chained_origin_depot.cc (original)
+++ compiler-rt/trunk/lib/msan/msan_chained_origin_depot.cc Thu Jul 10 06:02:33 2014
@@ -19,7 +19,30 @@ namespace __msan {
struct ChainedOriginDepotDesc {
u32 here_id;
u32 prev_id;
- u32 hash() const { return (here_id * 0x1f1f1f1f) ^ prev_id; }
+ u32 hash() const {
+ const u32 m = 0x5bd1e995;
+ const u32 seed = 0x9747b28c;
+ const u32 r = 24;
+ u32 h = seed;
+ u32 k = here_id;
+ k *= m;
+ k ^= k >> r;
+ k *= m;
+ h *= m;
+ h ^= k;
+
+ k = prev_id;
+ k *= m;
+ k ^= k >> r;
+ k *= m;
+ h *= m;
+ h ^= k;
+
+ h ^= h >> 13;
+ h *= m;
+ h ^= h >> 15;
+ return h;
+ }
bool is_valid() { return true; }
};
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