Viewing file:  sanitizer_chained_origin_depot.cpp (3.83 KB) -rw-r--r--
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//===-- sanitizer_chained_origin_depot.cpp --------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// A storage for chained origins.
//===----------------------------------------------------------------------===//
#include "sanitizer_chained_origin_depot.h"
#include "sanitizer_persistent_allocator.h"
#include "sanitizer_stackdepotbase.h"
namespace __sanitizer {
namespace {
struct ChainedOriginDepotDesc {
u32 here_id;
u32 prev_id;
};
struct ChainedOriginDepotNode {
using hash_type = u32;
u32 link;
u32 here_id;
u32 prev_id;
typedef ChainedOriginDepotDesc args_type;
bool eq(hash_type hash, const args_type &args) const;
static uptr allocated() { return 0; }
static hash_type hash(const args_type &args);
static bool is_valid(const args_type &args);
void store(u32 id, const args_type &args, hash_type other_hash);
args_type load(u32 id) const;
struct Handle {
const ChainedOriginDepotNode *node_ = nullptr;
u32 id_ = 0;
Handle(const ChainedOriginDepotNode *node, u32 id) : node_(node), id_(id) {}
bool valid() const { return node_; }
u32 id() const { return id_; }
int here_id() const { return node_->here_id; }
int prev_id() const { return node_->prev_id; }
};
static Handle get_handle(u32 id);
typedef Handle handle_type;
};
} // namespace
static StackDepotBase<ChainedOriginDepotNode, 4, 20> depot;
bool ChainedOriginDepotNode::eq(hash_type hash, const args_type &args) const {
return here_id == args.here_id && prev_id == args.prev_id;
}
/* This is murmur2 hash for the 64->32 bit case.
It does not behave all that well because the keys have a very biased
distribution (I've seen 7-element buckets with the table only 14% full).
here_id is built of
* (1 bits) Reserved, zero.
* (8 bits) Part id = bits 13..20 of the hash value of here_id's key.
* (23 bits) Sequential number (each part has each own sequence).
prev_id has either the same distribution as here_id (but with 3:8:21)
split, or one of two reserved values (-1) or (-2). Either case can
dominate depending on the workload.
*/
ChainedOriginDepotNode::hash_type ChainedOriginDepotNode::hash(
const args_type &args) {
const u32 m = 0x5bd1e995;
const u32 seed = 0x9747b28c;
const u32 r = 24;
u32 h = seed;
u32 k = args.here_id;
k *= m;
k ^= k >> r;
k *= m;
h *= m;
h ^= k;
k = args.prev_id;
k *= m;
k ^= k >> r;
k *= m;
h *= m;
h ^= k;
h ^= h >> 13;
h *= m;
h ^= h >> 15;
return h;
}
bool ChainedOriginDepotNode::is_valid(const args_type &args) { return true; }
void ChainedOriginDepotNode::store(u32 id, const args_type &args,
hash_type other_hash) {
here_id = args.here_id;
prev_id = args.prev_id;
}
ChainedOriginDepotNode::args_type ChainedOriginDepotNode::load(u32 id) const {
args_type ret = {here_id, prev_id};
return ret;
}
ChainedOriginDepotNode::Handle ChainedOriginDepotNode::get_handle(u32 id) {
return Handle(&depot.nodes[id], id);
}
ChainedOriginDepot::ChainedOriginDepot() {}
StackDepotStats ChainedOriginDepot::GetStats() const {
return depot.GetStats();
}
bool ChainedOriginDepot::Put(u32 here_id, u32 prev_id, u32 *new_id) {
ChainedOriginDepotDesc desc = {here_id, prev_id};
bool inserted;
*new_id = depot.Put(desc, &inserted);
return inserted;
}
u32 ChainedOriginDepot::Get(u32 id, u32 *other) {
ChainedOriginDepotDesc desc = depot.Get(id);
*other = desc.prev_id;
return desc.here_id;
}
void ChainedOriginDepot::LockAll() { depot.LockAll(); }
void ChainedOriginDepot::UnlockAll() { depot.UnlockAll(); }
} // namespace __sanitizer
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