f668a84b58
`atomic_compare_exchange_weak` is unused in Scudo, and its associated
test is actually wrong since the weak variant is allowed to fail
spuriously (thanks Roland).
This lead to flakes such as:
```
[ RUN ] ScudoAtomicTest.AtomicCompareExchangeTest
../../zircon/third_party/scudo/src/tests/atomic_test.cpp:98: Failure: Expected atomic_compare_exchange_weak(reinterpret_cast<T *>(&V), &OldVal, NewVal, memory_order_relaxed) is true.
Expected: true
Which is: 01
Actual : atomic_compare_exchange_weak(reinterpret_cast<T *>(&V), &OldVal, NewVal, memory_order_relaxed)
Which is: 00
../../zircon/third_party/scudo/src/tests/atomic_test.cpp💯 Failure: Expected atomic_compare_exchange_weak( reinterpret_cast<T *>(&V), &OldVal, NewVal, memory_order_relaxed) is false.
Expected: false
Which is: 00
Actual : atomic_compare_exchange_weak( reinterpret_cast<T *>(&V), &OldVal, NewVal, memory_order_relaxed)
Which is: 01
../../zircon/third_party/scudo/src/tests/atomic_test.cpp:101: Failure: Expected OldVal == NewVal.
Expected: NewVal
Which is: 24
Actual : OldVal
Which is: 42
[ FAILED ] ScudoAtomicTest.AtomicCompareExchangeTest (0 ms)
[----------] 2 tests from ScudoAtomicTest (1 ms total)
```
So I am removing this, if someone ever needs the weak variant, feel
free to add it back with a test that is not as terrible. This test was
initially ported from sanitizer_common, but their weak version calls
the strong version, so it works for them.
Differential Revision: https://reviews.llvm.org/D88443
102 lines
4.0 KiB
C++
102 lines
4.0 KiB
C++
//===-- atomic_test.cpp -----------------------------------------*- 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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#include "tests/scudo_unit_test.h"
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#include "atomic_helpers.h"
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namespace scudo {
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template <typename T> struct ValAndMagic {
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typename T::Type Magic0;
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T A;
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typename T::Type Magic1;
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static ValAndMagic<T> *Sink;
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};
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template <typename T> ValAndMagic<T> *ValAndMagic<T>::Sink;
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template <typename T, memory_order LoadMO, memory_order StoreMO>
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void checkStoreLoad() {
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typedef typename T::Type Type;
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ValAndMagic<T> Val;
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// Prevent the compiler from scalarizing the struct.
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ValAndMagic<T>::Sink = &Val;
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// Ensure that surrounding memory is not overwritten.
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Val.Magic0 = Val.Magic1 = (Type)-3;
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for (u64 I = 0; I < 100; I++) {
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// Generate A value that occupies all bytes of the variable.
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u64 V = I;
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V |= V << 8;
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V |= V << 16;
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V |= V << 32;
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Val.A.ValDoNotUse = (Type)V;
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EXPECT_EQ(atomic_load(&Val.A, LoadMO), (Type)V);
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Val.A.ValDoNotUse = (Type)-1;
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atomic_store(&Val.A, (Type)V, StoreMO);
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EXPECT_EQ(Val.A.ValDoNotUse, (Type)V);
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}
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EXPECT_EQ(Val.Magic0, (Type)-3);
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EXPECT_EQ(Val.Magic1, (Type)-3);
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}
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TEST(ScudoAtomicTest, AtomicStoreLoad) {
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checkStoreLoad<atomic_u8, memory_order_relaxed, memory_order_relaxed>();
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checkStoreLoad<atomic_u8, memory_order_consume, memory_order_relaxed>();
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checkStoreLoad<atomic_u8, memory_order_acquire, memory_order_relaxed>();
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checkStoreLoad<atomic_u8, memory_order_relaxed, memory_order_release>();
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checkStoreLoad<atomic_u8, memory_order_seq_cst, memory_order_seq_cst>();
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checkStoreLoad<atomic_u16, memory_order_relaxed, memory_order_relaxed>();
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checkStoreLoad<atomic_u16, memory_order_consume, memory_order_relaxed>();
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checkStoreLoad<atomic_u16, memory_order_acquire, memory_order_relaxed>();
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checkStoreLoad<atomic_u16, memory_order_relaxed, memory_order_release>();
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checkStoreLoad<atomic_u16, memory_order_seq_cst, memory_order_seq_cst>();
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checkStoreLoad<atomic_u32, memory_order_relaxed, memory_order_relaxed>();
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checkStoreLoad<atomic_u32, memory_order_consume, memory_order_relaxed>();
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checkStoreLoad<atomic_u32, memory_order_acquire, memory_order_relaxed>();
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checkStoreLoad<atomic_u32, memory_order_relaxed, memory_order_release>();
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checkStoreLoad<atomic_u32, memory_order_seq_cst, memory_order_seq_cst>();
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checkStoreLoad<atomic_u64, memory_order_relaxed, memory_order_relaxed>();
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checkStoreLoad<atomic_u64, memory_order_consume, memory_order_relaxed>();
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checkStoreLoad<atomic_u64, memory_order_acquire, memory_order_relaxed>();
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checkStoreLoad<atomic_u64, memory_order_relaxed, memory_order_release>();
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checkStoreLoad<atomic_u64, memory_order_seq_cst, memory_order_seq_cst>();
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checkStoreLoad<atomic_uptr, memory_order_relaxed, memory_order_relaxed>();
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checkStoreLoad<atomic_uptr, memory_order_consume, memory_order_relaxed>();
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checkStoreLoad<atomic_uptr, memory_order_acquire, memory_order_relaxed>();
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checkStoreLoad<atomic_uptr, memory_order_relaxed, memory_order_release>();
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checkStoreLoad<atomic_uptr, memory_order_seq_cst, memory_order_seq_cst>();
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}
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template <typename T> void checkAtomicCompareExchange() {
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typedef typename T::Type Type;
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Type OldVal = 42;
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Type NewVal = 24;
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Type V = OldVal;
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EXPECT_TRUE(atomic_compare_exchange_strong(reinterpret_cast<T *>(&V), &OldVal,
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NewVal, memory_order_relaxed));
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EXPECT_FALSE(atomic_compare_exchange_strong(
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reinterpret_cast<T *>(&V), &OldVal, NewVal, memory_order_relaxed));
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EXPECT_EQ(NewVal, OldVal);
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}
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TEST(ScudoAtomicTest, AtomicCompareExchangeTest) {
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checkAtomicCompareExchange<atomic_u8>();
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checkAtomicCompareExchange<atomic_u16>();
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checkAtomicCompareExchange<atomic_u32>();
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checkAtomicCompareExchange<atomic_u64>();
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checkAtomicCompareExchange<atomic_uptr>();
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}
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} // namespace scudo
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