return std::equal(A->Relocs.begin(), A->Relocs.end(), B->Relocs.begin(), Eq);
}
+// Find the first Chunk after Begin that has a different class from Begin.
size_t ICF::findBoundary(size_t Begin, size_t End) {
for (size_t I = Begin + 1; I < End; ++I)
if (Chunks[Begin]->Class[Cnt % 2] != Chunks[I]->Class[Cnt % 2])
void ICF::forEachClassRange(size_t Begin, size_t End,
std::function<void(size_t, size_t)> Fn) {
- if (Begin > 0)
- Begin = findBoundary(Begin - 1, End);
-
while (Begin < End) {
- size_t Mid = findBoundary(Begin, Chunks.size());
+ size_t Mid = findBoundary(Begin, End);
Fn(Begin, Mid);
Begin = Mid;
}
return;
}
- // Split sections into 256 shards and call Fn in parallel.
- size_t NumShards = 256;
+ // Shard into non-overlapping intervals, and call Fn in parallel.
+ // The sharding must be completed before any calls to Fn are made
+ // so that Fn can modify the Chunks in its shard without causing data
+ // races.
+ const size_t NumShards = 256;
size_t Step = Chunks.size() / NumShards;
- for_each_n(parallel::par, size_t(0), NumShards, [&](size_t I) {
- size_t End = (I == NumShards - 1) ? Chunks.size() : (I + 1) * Step;
- forEachClassRange(I * Step, End, Fn);
+ size_t Boundaries[NumShards + 1];
+ Boundaries[0] = 0;
+ Boundaries[NumShards] = Chunks.size();
+ for_each_n(parallel::par, size_t(1), NumShards, [&](size_t I) {
+ Boundaries[I] = findBoundary((I - 1) * Step, Chunks.size());
+ });
+ for_each_n(parallel::par, size_t(1), NumShards + 1, [&](size_t I) {
+ if (Boundaries[I - 1] < Boundaries[I]) {
+ forEachClassRange(Boundaries[I - 1], Boundaries[I], Fn);
+ }
});
++Cnt;
}