1 //===-- sanitizer_stackdepot.cc -------------------------------------------===// 2 // 3 // This file is distributed under the University of Illinois Open Source 4 // License. See LICENSE.TXT for details. 5 // 6 //===----------------------------------------------------------------------===// 7 // 8 // This file is shared between AddressSanitizer and ThreadSanitizer 9 // run-time libraries. 10 //===----------------------------------------------------------------------===// 11 12 #include "sanitizer_stackdepot.h" 13 14 #include "sanitizer_common.h" 15 #include "sanitizer_stackdepotbase.h" 16 17 namespace __sanitizer { 18 19 struct StackDepotNode { 20 StackDepotNode *link; 21 u32 id; 22 atomic_uint32_t hash_and_use_count; // hash_bits : 12; use_count : 20; 23 uptr size; 24 uptr stack[1]; // [size] 25 26 static const u32 kTabSizeLog = 20; 27 // Lower kTabSizeLog bits are equal for all items in one bucket. 28 // We use these bits to store the per-stack use counter. 29 static const u32 kUseCountBits = kTabSizeLog; 30 static const u32 kMaxUseCount = 1 << kUseCountBits; 31 static const u32 kUseCountMask = (1 << kUseCountBits) - 1; 32 static const u32 kHashMask = ~kUseCountMask; 33 34 typedef StackTrace args_type; 35 bool eq(u32 hash, const args_type &args) const { 36 u32 hash_bits = 37 atomic_load(&hash_and_use_count, memory_order_relaxed) & kHashMask; 38 if ((hash & kHashMask) != hash_bits || args.size != size) return false; 39 uptr i = 0; 40 for (; i < size; i++) { 41 if (stack[i] != args.trace[i]) return false; 42 } 43 return true; 44 } 45 static uptr storage_size(const args_type &args) { 46 return sizeof(StackDepotNode) + (args.size - 1) * sizeof(uptr); 47 } 48 static u32 hash(const args_type &args) { 49 // murmur2 50 const u32 m = 0x5bd1e995; 51 const u32 seed = 0x9747b28c; 52 const u32 r = 24; 53 u32 h = seed ^ (args.size * sizeof(uptr)); 54 for (uptr i = 0; i < args.size; i++) { 55 u32 k = args.trace[i]; 56 k *= m; 57 k ^= k >> r; 58 k *= m; 59 h *= m; 60 h ^= k; 61 } 62 h ^= h >> 13; 63 h *= m; 64 h ^= h >> 15; 65 return h; 66 } 67 static bool is_valid(const args_type &args) { 68 return args.size > 0 && args.trace; 69 } 70 void store(const args_type &args, u32 hash) { 71 atomic_store(&hash_and_use_count, hash & kHashMask, memory_order_relaxed); 72 size = args.size; 73 internal_memcpy(stack, args.trace, size * sizeof(uptr)); 74 } 75 args_type load() const { 76 return args_type(&stack[0], size); 77 } 78 StackDepotHandle get_handle() { return StackDepotHandle(this); } 79 80 typedef StackDepotHandle handle_type; 81 }; 82 83 COMPILER_CHECK(StackDepotNode::kMaxUseCount == (u32)kStackDepotMaxUseCount); 84 85 u32 StackDepotHandle::id() { return node_->id; } 86 int StackDepotHandle::use_count() { 87 return atomic_load(&node_->hash_and_use_count, memory_order_relaxed) & 88 StackDepotNode::kUseCountMask; 89 } 90 void StackDepotHandle::inc_use_count_unsafe() { 91 u32 prev = 92 atomic_fetch_add(&node_->hash_and_use_count, 1, memory_order_relaxed) & 93 StackDepotNode::kUseCountMask; 94 CHECK_LT(prev + 1, StackDepotNode::kMaxUseCount); 95 } 96 97 // FIXME(dvyukov): this single reserved bit is used in TSan. 98 typedef StackDepotBase<StackDepotNode, 1, StackDepotNode::kTabSizeLog> 99 StackDepot; 100 static StackDepot theDepot; 101 102 StackDepotStats *StackDepotGetStats() { 103 return theDepot.GetStats(); 104 } 105 106 u32 StackDepotPut(StackTrace stack) { 107 StackDepotHandle h = theDepot.Put(stack); 108 return h.valid() ? h.id() : 0; 109 } 110 111 StackDepotHandle StackDepotPut_WithHandle(StackTrace stack) { 112 return theDepot.Put(stack); 113 } 114 115 StackTrace StackDepotGet(u32 id) { 116 return theDepot.Get(id); 117 } 118 119 void StackDepotLockAll() { 120 theDepot.LockAll(); 121 } 122 123 void StackDepotUnlockAll() { 124 theDepot.UnlockAll(); 125 } 126 127 bool StackDepotReverseMap::IdDescPair::IdComparator( 128 const StackDepotReverseMap::IdDescPair &a, 129 const StackDepotReverseMap::IdDescPair &b) { 130 return a.id < b.id; 131 } 132 133 StackDepotReverseMap::StackDepotReverseMap() 134 : map_(StackDepotGetStats()->n_uniq_ids + 100) { 135 for (int idx = 0; idx < StackDepot::kTabSize; idx++) { 136 atomic_uintptr_t *p = &theDepot.tab[idx]; 137 uptr v = atomic_load(p, memory_order_consume); 138 StackDepotNode *s = (StackDepotNode*)(v & ~1); 139 for (; s; s = s->link) { 140 IdDescPair pair = {s->id, s}; 141 map_.push_back(pair); 142 } 143 } 144 InternalSort(&map_, map_.size(), IdDescPair::IdComparator); 145 } 146 147 StackTrace StackDepotReverseMap::Get(u32 id) { 148 if (!map_.size()) 149 return StackTrace(); 150 IdDescPair pair = {id, 0}; 151 uptr idx = InternalBinarySearch(map_, 0, map_.size(), pair, 152 IdDescPair::IdComparator); 153 if (idx > map_.size()) 154 return StackTrace(); 155 return map_[idx].desc->load(); 156 } 157 158 } // namespace __sanitizer 159