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//===-- tsan_sync.cc ------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is a part of ThreadSanitizer (TSan), a race detector.
//
//===----------------------------------------------------------------------===//
#include "sanitizer_common/sanitizer_placement_new.h"
#include "tsan_sync.h"
#include "tsan_rtl.h"
#include "tsan_mman.h"
namespace __tsan {
void DDMutexInit(ThreadState *thr, uptr pc, SyncVar *s);
SyncVar::SyncVar()
: mtx(MutexTypeSyncVar, StatMtxSyncVar) {
Reset();
}
void SyncVar::Init(ThreadState *thr, uptr pc, uptr addr, u64 uid) {
this->addr = addr;
this->uid = uid;
this->next = 0;
creation_stack_id = 0;
if (kCppMode) // Go does not use them
creation_stack_id = CurrentStackId(thr, pc);
if (flags()->detect_deadlocks)
DDMutexInit(thr, pc, this);
}
void SyncVar::Reset() {
uid = 0;
creation_stack_id = 0;
owner_tid = kInvalidTid;
last_lock = 0;
recursion = 0;
is_rw = 0;
is_recursive = 0;
is_broken = 0;
is_linker_init = 0;
clock.Zero();
read_clock.Reset();
}
MetaMap::MetaMap() {
atomic_store(&uid_gen_, 0, memory_order_relaxed);
}
void MetaMap::AllocBlock(ThreadState *thr, uptr pc, uptr p, uptr sz) {
u32 idx = block_alloc_.Alloc(&thr->block_cache);
MBlock *b = block_alloc_.Map(idx);
b->siz = sz;
b->tid = thr->tid;
b->stk = CurrentStackId(thr, pc);
u32 *meta = MemToMeta(p);
DCHECK_EQ(*meta, 0);
*meta = idx | kFlagBlock;
}
uptr MetaMap::FreeBlock(ThreadState *thr, uptr pc, uptr p) {
MBlock* b = GetBlock(p);
if (b == 0)
return 0;
uptr sz = RoundUpTo(b->siz, kMetaShadowCell);
FreeRange(thr, pc, p, sz);
return sz;
}
void MetaMap::FreeRange(ThreadState *thr, uptr pc, uptr p, uptr sz) {
u32 *meta = MemToMeta(p);
u32 *end = MemToMeta(p + sz);
if (end == meta)
end++;
for (; meta < end; meta++) {
u32 idx = *meta;
*meta = 0;
for (;;) {
if (idx == 0)
break;
if (idx & kFlagBlock) {
block_alloc_.Free(&thr->block_cache, idx & ~kFlagMask);
break;
} else if (idx & kFlagSync) {
DCHECK(idx & kFlagSync);
SyncVar *s = sync_alloc_.Map(idx & ~kFlagMask);
u32 next = s->next;
s->Reset();
sync_alloc_.Free(&thr->sync_cache, idx & ~kFlagMask);
idx = next;
} else {
CHECK(0);
}
}
}
}
MBlock* MetaMap::GetBlock(uptr p) {
u32 *meta = MemToMeta(p);
u32 idx = *meta;
for (;;) {
if (idx == 0)
return 0;
if (idx & kFlagBlock)
return block_alloc_.Map(idx & ~kFlagMask);
DCHECK(idx & kFlagSync);
SyncVar * s = sync_alloc_.Map(idx & ~kFlagMask);
idx = s->next;
}
}
SyncVar* MetaMap::GetOrCreateAndLock(ThreadState *thr, uptr pc,
uptr addr, bool write_lock) {
return GetAndLock(thr, pc, addr, write_lock, true);
}
SyncVar* MetaMap::GetIfExistsAndLock(uptr addr) {
return GetAndLock(0, 0, addr, true, false);
}
SyncVar* MetaMap::GetAndLock(ThreadState *thr, uptr pc,
uptr addr, bool write_lock, bool create) {
u32 *meta = MemToMeta(addr);
u32 idx0 = *meta;
u32 myidx = 0;
SyncVar *mys = 0;
for (;;) {
u32 idx = idx0;
for (;;) {
if (idx == 0)
break;
if (idx & kFlagBlock)
break;
DCHECK(idx & kFlagSync);
SyncVar * s = sync_alloc_.Map(idx & ~kFlagMask);
if (s->addr == addr) {
if (myidx != 0) {
mys->Reset();
sync_alloc_.Free(&thr->sync_cache, myidx);
}
if (write_lock)
s->mtx.Lock();
else
s->mtx.ReadLock();
return s;
}
idx = s->next;
}
if (!create)
return 0;
if (*meta != idx0) {
idx0 = *meta;
continue;
}
if (myidx == 0) {
const u64 uid = atomic_fetch_add(&uid_gen_, 1, memory_order_relaxed);
myidx = sync_alloc_.Alloc(&thr->sync_cache);
mys = sync_alloc_.Map(myidx);
mys->Init(thr, pc, addr, uid);
}
mys->next = idx0;
if (atomic_compare_exchange_strong((atomic_uint32_t*)meta, &idx0,
myidx | kFlagSync, memory_order_release)) {
if (write_lock)
mys->mtx.Lock();
else
mys->mtx.ReadLock();
return mys;
}
}
}
void MetaMap::MoveMemory(uptr src, uptr dst, uptr sz) {
// src and dst can overlap,
// there are no concurrent accesses to the regions (e.g. stop-the-world).
CHECK_NE(src, dst);
CHECK_NE(sz, 0);
uptr diff = dst - src;
u32 *src_meta = MemToMeta(src);
u32 *dst_meta = MemToMeta(dst);
u32 *src_meta_end = MemToMeta(src + sz);
uptr inc = 1;
if (dst > src) {
src_meta = MemToMeta(src + sz) - 1;
dst_meta = MemToMeta(dst + sz) - 1;
src_meta_end = MemToMeta(src) - 1;
inc = -1;
}
for (; src_meta != src_meta_end; src_meta += inc, dst_meta += inc) {
CHECK_EQ(*dst_meta, 0);
u32 idx = *src_meta;
*src_meta = 0;
*dst_meta = idx;
// Patch the addresses in sync objects.
while (idx != 0) {
if (idx & kFlagBlock)
break;
CHECK(idx & kFlagSync);
SyncVar *s = sync_alloc_.Map(idx & ~kFlagMask);
s->addr += diff;
idx = s->next;
}
}
}
void MetaMap::OnThreadIdle(ThreadState *thr) {
block_alloc_.FlushCache(&thr->block_cache);
sync_alloc_.FlushCache(&thr->sync_cache);
}
} // namespace __tsan
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