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| //===-- tsan_update_shadow_word_inl.h ---------------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file is a part of ThreadSanitizer (TSan), a race detector.
//
// Body of the hottest inner loop.
// If we wrap this body into a function, compilers (both gcc and clang)
// produce sligtly less efficient code.
//===----------------------------------------------------------------------===//
do {
StatInc(thr, StatShadowProcessed);
const unsigned kAccessSize = 1 << kAccessSizeLog;
u64 *sp = &shadow_mem[idx];
old = LoadShadow(sp);
if (LIKELY(old.IsZero())) {
StatInc(thr, StatShadowZero);
if (!stored) {
StoreIfNotYetStored(sp, &store_word);
stored = true;
}
break;
}
// is the memory access equal to the previous?
if (LIKELY(Shadow::Addr0AndSizeAreEqual(cur, old))) {
StatInc(thr, StatShadowSameSize);
// same thread?
if (LIKELY(Shadow::TidsAreEqual(old, cur))) {
StatInc(thr, StatShadowSameThread);
if (LIKELY(old.IsRWWeakerOrEqual(kAccessIsWrite, kIsAtomic))) {
StoreIfNotYetStored(sp, &store_word);
stored = true;
}
break;
}
StatInc(thr, StatShadowAnotherThread);
if (HappensBefore(old, thr)) {
if (old.IsRWWeakerOrEqual(kAccessIsWrite, kIsAtomic)) {
StoreIfNotYetStored(sp, &store_word);
stored = true;
}
break;
}
if (LIKELY(old.IsBothReadsOrAtomic(kAccessIsWrite, kIsAtomic)))
break;
goto RACE;
}
// Do the memory access intersect?
if (Shadow::TwoRangesIntersect(old, cur, kAccessSize)) {
StatInc(thr, StatShadowIntersect);
if (Shadow::TidsAreEqual(old, cur)) {
StatInc(thr, StatShadowSameThread);
break;
}
StatInc(thr, StatShadowAnotherThread);
if (old.IsBothReadsOrAtomic(kAccessIsWrite, kIsAtomic))
break;
if (LIKELY(HappensBefore(old, thr)))
break;
goto RACE;
}
// The accesses do not intersect.
StatInc(thr, StatShadowNotIntersect);
break;
} while (0);
|