1 //===-- msan_chained_origin_depot.cc -----------------------------------===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // A storage for chained origins.
10 //===----------------------------------------------------------------------===//
12 #include "msan_chained_origin_depot.h"
14 #include "sanitizer_common/sanitizer_stackdepotbase.h"
18 struct ChainedOriginDepotDesc {
23 struct ChainedOriginDepotNode {
24 ChainedOriginDepotNode *link;
29 typedef ChainedOriginDepotDesc args_type;
31 bool eq(u32 hash, const args_type &args) const {
32 return here_id == args.here_id && prev_id == args.prev_id;
35 static uptr storage_size(const args_type &args) {
36 return sizeof(ChainedOriginDepotNode);
39 /* This is murmur2 hash for the 64->32 bit case.
40 It does not behave all that well because the keys have a very biased
41 distribution (I've seen 7-element buckets with the table only 14% full).
44 * (1 bits) Reserved, zero.
45 * (8 bits) Part id = bits 13..20 of the hash value of here_id's key.
46 * (23 bits) Sequential number (each part has each own sequence).
48 prev_id has either the same distribution as here_id (but with 3:8:21)
49 split, or one of two reserved values (-1) or (-2). Either case can
50 dominate depending on the workload.
52 static u32 hash(const args_type &args) {
53 const u32 m = 0x5bd1e995;
54 const u32 seed = 0x9747b28c;
76 static bool is_valid(const args_type &args) { return true; }
77 void store(const args_type &args, u32 other_hash) {
78 here_id = args.here_id;
79 prev_id = args.prev_id;
82 args_type load() const {
83 args_type ret = {here_id, prev_id};
88 ChainedOriginDepotNode *node_;
89 Handle() : node_(nullptr) {}
90 explicit Handle(ChainedOriginDepotNode *node) : node_(node) {}
91 bool valid() { return node_; }
92 u32 id() { return node_->id; }
93 int here_id() { return node_->here_id; }
94 int prev_id() { return node_->prev_id; }
97 Handle get_handle() { return Handle(this); }
99 typedef Handle handle_type;
102 static StackDepotBase<ChainedOriginDepotNode, 4, 20> chainedOriginDepot;
104 StackDepotStats *ChainedOriginDepotGetStats() {
105 return chainedOriginDepot.GetStats();
108 bool ChainedOriginDepotPut(u32 here_id, u32 prev_id, u32 *new_id) {
109 ChainedOriginDepotDesc desc = {here_id, prev_id};
111 ChainedOriginDepotNode::Handle h = chainedOriginDepot.Put(desc, &inserted);
112 *new_id = h.valid() ? h.id() : 0;
116 // Retrieves a stored stack trace by the id.
117 u32 ChainedOriginDepotGet(u32 id, u32 *other) {
118 ChainedOriginDepotDesc desc = chainedOriginDepot.Get(id);
119 *other = desc.prev_id;
123 void ChainedOriginDepotLockAll() {
124 chainedOriginDepot.LockAll();
127 void ChainedOriginDepotUnlockAll() {
128 chainedOriginDepot.UnlockAll();
131 } // namespace __msan