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Fix a possible overflow in TT resize

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On platforms where size_t is 32 bit, we
can have an overflow in this expression:

(mbSize * 1024 * 1024)

Fix it setting max hash size of 2GB on platforms
where size_t is 32 bit.

A small rename while there: now struct Cluster
is definied inside class TranspositionTable so
we should drop the redundant TT prefix.

No functional change.
This commit is contained in:
Marco Costalba
2015-01-17 09:04:25 +01:00
parent 58fdb84b0d
commit 595fc342cf
3 changed files with 10 additions and 8 deletions
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10
src/tt.cpp
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@@ -32,9 +32,9 @@ TranspositionTable TT; // Our global transposition table
void TranspositionTable::resize(size_t mbSize) {
assert(sizeof(TTCluster) == CacheLineSize / 2);
assert(sizeof(Cluster) == CacheLineSize / 2);
size_t newClusterCount = size_t(1) << msb((mbSize * 1024 * 1024) / sizeof(TTCluster));
size_t newClusterCount = size_t(1) << msb((mbSize * 1024 * 1024) / sizeof(Cluster));
if (newClusterCount == clusterCount)
return;
@@ -42,7 +42,7 @@ void TranspositionTable::resize(size_t mbSize) {
clusterCount = newClusterCount;
free(mem);
mem = calloc(clusterCount * sizeof(TTCluster) + CacheLineSize - 1, 1);
mem = calloc(clusterCount * sizeof(Cluster) + CacheLineSize - 1, 1);
if (!mem)
{
@@ -51,7 +51,7 @@ void TranspositionTable::resize(size_t mbSize) {
exit(EXIT_FAILURE);
}
table = (TTCluster*)((uintptr_t(mem) + CacheLineSize - 1) & ~(CacheLineSize - 1));
table = (Cluster*)((uintptr_t(mem) + CacheLineSize - 1) & ~(CacheLineSize - 1));
}
@@ -61,7 +61,7 @@ void TranspositionTable::resize(size_t mbSize) {
void TranspositionTable::clear() {
std::memset(table, 0, clusterCount * sizeof(TTCluster));
std::memset(table, 0, clusterCount * sizeof(Cluster));
}