60 lines
1.9 KiB
C++
60 lines
1.9 KiB
C++
//===-- tsan_update_shadow_word_inl.h ---------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is a part of ThreadSanitizer (TSan), a race detector.
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//
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// Body of the hottest inner loop.
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// If we wrap this body into a function, compilers (both gcc and clang)
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// produce sligtly less efficient code.
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//===----------------------------------------------------------------------===//
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do {
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const unsigned kAccessSize = 1 << kAccessSizeLog;
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u64 *sp = &shadow_mem[idx];
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old = LoadShadow(sp);
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if (LIKELY(old.IsZero())) {
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if (!stored) {
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StoreIfNotYetStored(sp, &store_word);
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stored = true;
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}
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break;
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}
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// is the memory access equal to the previous?
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if (LIKELY(Shadow::Addr0AndSizeAreEqual(cur, old))) {
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// same thread?
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if (LIKELY(Shadow::TidsAreEqual(old, cur))) {
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if (LIKELY(old.IsRWWeakerOrEqual(kAccessIsWrite, kIsAtomic))) {
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StoreIfNotYetStored(sp, &store_word);
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stored = true;
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}
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break;
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}
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if (HappensBefore(old, thr)) {
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if (old.IsRWWeakerOrEqual(kAccessIsWrite, kIsAtomic)) {
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StoreIfNotYetStored(sp, &store_word);
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stored = true;
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}
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break;
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}
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if (LIKELY(old.IsBothReadsOrAtomic(kAccessIsWrite, kIsAtomic)))
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break;
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goto RACE;
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}
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// Do the memory access intersect?
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if (Shadow::TwoRangesIntersect(old, cur, kAccessSize)) {
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if (Shadow::TidsAreEqual(old, cur))
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break;
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if (old.IsBothReadsOrAtomic(kAccessIsWrite, kIsAtomic))
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break;
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if (LIKELY(HappensBefore(old, thr)))
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break;
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goto RACE;
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}
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// The accesses do not intersect.
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break;
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} while (0);
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