From 84f8d4961ddfcdc99676ea8f6c5e210cc398b91f Mon Sep 17 00:00:00 2001 From: Thiago Macieira Date: Thu, 6 Jul 2023 11:45:24 -0700 Subject: [PATCH] Revert "Fix signed integer overflows in tst_QAtomicInteger" This reverts commit f64737527559e22783b57d30ce8bab9ee517974d. There are no signed integer overflows in atomics. For the non-atomic side, unlike the commit being reverted, we fix the signed integer overflow by removing the "signed" part instead of the "overflow" part, and use unsigned integer overflows instead. Change-Id: I53335f845a1345299031fffd176f5ba479163e44 Reviewed-by: Volker Hilsheimer --- .../qatomicinteger/tst_qatomicinteger.cpp | 97 ++++--------------- 1 file changed, 17 insertions(+), 80 deletions(-) diff --git a/tests/auto/corelib/thread/qatomicinteger/tst_qatomicinteger.cpp b/tests/auto/corelib/thread/qatomicinteger/tst_qatomicinteger.cpp index 5eefb76fd5..ba39c3b08c 100644 --- a/tests/auto/corelib/thread/qatomicinteger/tst_qatomicinteger.cpp +++ b/tests/auto/corelib/thread/qatomicinteger/tst_qatomicinteger.cpp @@ -64,6 +64,7 @@ typedef signed char schar; typedef TEST_TYPE Type; typedef Type T; // shorthand +using U = std::make_unsigned_t; enum { TypeIsUnsigned = Type(-1) > Type(0), TypeIsSigned = !TypeIsUnsigned @@ -289,46 +290,32 @@ void tst_QAtomicIntegerXX::loadAcquireStoreRelease() void tst_QAtomicIntegerXX::refDeref() { QFETCH(LargeInt, value); - const bool needToPreventOverflow = TypeIsSigned && value == std::numeric_limits::max(); - const bool needToPreventUnderflow = TypeIsSigned && value == std::numeric_limits::min(); - T nextValue = T(value); - if (!needToPreventOverflow) - ++nextValue; - T prevValue = T(value); - if (!needToPreventUnderflow) - --prevValue; + + // We perform arithmetic using the unsigned type U to avoid signed + // integer overflows in the non-atomic portion (atomics have well-defined, + // two's complement overflow, even signed ones). + T nextValue = T(U(value) + 1); + T prevValue = T(U(value) - 1); QAtomicInteger atomic(value); - if (!needToPreventOverflow) { QCOMPARE(atomic.ref(), (nextValue != 0)); QCOMPARE(atomic.loadRelaxed(), nextValue); QCOMPARE(atomic.deref(), (value != 0)); - } QCOMPARE(atomic.loadRelaxed(), T(value)); - if (!needToPreventUnderflow) { QCOMPARE(atomic.deref(), (prevValue != 0)); QCOMPARE(atomic.loadRelaxed(), prevValue); QCOMPARE(atomic.ref(), (value != 0)); - } QCOMPARE(atomic.loadRelaxed(), T(value)); - if (!needToPreventOverflow) { QCOMPARE(++atomic, nextValue); QCOMPARE(--atomic, T(value)); - } - if (!needToPreventUnderflow) { QCOMPARE(--atomic, prevValue); QCOMPARE(++atomic, T(value)); - } - if (!needToPreventOverflow) { QCOMPARE(atomic++, T(value)); QCOMPARE(atomic--, nextValue); - } - if (!needToPreventUnderflow) { QCOMPARE(atomic--, T(value)); QCOMPARE(atomic++, prevValue); - } QCOMPARE(atomic.loadRelaxed(), T(value)); } @@ -431,80 +418,55 @@ void tst_QAtomicIntegerXX::fetchAndAdd() QFETCH(LargeInt, value); QAtomicInteger atomic(value); + // We perform the additions using the unsigned type U to avoid signed + // integer overflows in the non-atomic portion (atomics have well-defined, + // two's complement overflow, even signed ones). T parcel1 = 42; T parcel2 = T(0-parcel1); + T newValue1 = T(U(value) + parcel1); + T newValue2 = T(U(value) + parcel2); - const bool needToPreventOverflow = TypeIsSigned && value > std::numeric_limits::max() + parcel2; - const bool needToPreventUnderflow = TypeIsSigned && value < std::numeric_limits::min() + parcel1; - - T newValue1 = T(value); - if (!needToPreventOverflow) - newValue1 += parcel1; - T newValue2 = T(value); - if (!needToPreventUnderflow) - newValue2 += parcel2; - - if (!needToPreventOverflow) { QCOMPARE(atomic.fetchAndAddRelaxed(parcel1), T(value)); QCOMPARE(atomic.loadRelaxed(), newValue1); QCOMPARE(atomic.fetchAndAddRelaxed(parcel2), newValue1); - } QCOMPARE(atomic.loadRelaxed(), T(value)); - if (!needToPreventUnderflow) { QCOMPARE(atomic.fetchAndAddRelaxed(parcel2), T(value)); QCOMPARE(atomic.loadRelaxed(), newValue2); QCOMPARE(atomic.fetchAndAddRelaxed(parcel1), newValue2); - } QCOMPARE(atomic.loadRelaxed(), T(value)); - if (!needToPreventOverflow) { QCOMPARE(atomic.fetchAndAddAcquire(parcel1), T(value)); QCOMPARE(atomic.loadRelaxed(), newValue1); QCOMPARE(atomic.fetchAndAddAcquire(parcel2), newValue1); - } QCOMPARE(atomic.loadRelaxed(), T(value)); - if (!needToPreventUnderflow) { QCOMPARE(atomic.fetchAndAddAcquire(parcel2), T(value)); QCOMPARE(atomic.loadRelaxed(), newValue2); QCOMPARE(atomic.fetchAndAddAcquire(parcel1), newValue2); - } QCOMPARE(atomic.loadRelaxed(), T(value)); - if (!needToPreventOverflow) { QCOMPARE(atomic.fetchAndAddRelease(parcel1), T(value)); QCOMPARE(atomic.loadAcquire(), newValue1); QCOMPARE(atomic.fetchAndAddRelease(parcel2), newValue1); - } QCOMPARE(atomic.loadAcquire(), T(value)); - if (!needToPreventUnderflow) { QCOMPARE(atomic.fetchAndAddRelease(parcel2), T(value)); QCOMPARE(atomic.loadAcquire(), newValue2); QCOMPARE(atomic.fetchAndAddRelease(parcel1), newValue2); - } QCOMPARE(atomic.loadAcquire(), T(value)); - if (!needToPreventOverflow) { QCOMPARE(atomic.fetchAndAddOrdered(parcel1), T(value)); QCOMPARE(atomic.loadAcquire(), newValue1); QCOMPARE(atomic.fetchAndAddOrdered(parcel2), newValue1); - } QCOMPARE(atomic.loadAcquire(), T(value)); - if (!needToPreventUnderflow) { QCOMPARE(atomic.fetchAndAddOrdered(parcel2), T(value)); QCOMPARE(atomic.loadAcquire(), newValue2); QCOMPARE(atomic.fetchAndAddOrdered(parcel1), newValue2); - } QCOMPARE(atomic.loadAcquire(), T(value)); // operator+= - if (!needToPreventOverflow) { QCOMPARE(atomic += parcel1, newValue1); QCOMPARE(atomic += parcel2, T(value)); - } - if (!needToPreventUnderflow) { QCOMPARE(atomic += parcel2, newValue2); QCOMPARE(atomic += parcel1, T(value)); - } } void tst_QAtomicIntegerXX::fetchAndSub() @@ -512,80 +474,55 @@ void tst_QAtomicIntegerXX::fetchAndSub() QFETCH(LargeInt, value); QAtomicInteger atomic(value); + // We perform the subtractions using the unsigned type U to avoid signed + // integer underrflows in the non-atomic portion (atomics have well-defined, + // two's complement underflow, even signed ones). T parcel1 = 42; T parcel2 = T(0-parcel1); + T newValue1 = T(U(value) - parcel1); + T newValue2 = T(U(value) - parcel2); - const bool needToPreventOverflow = TypeIsSigned && value > std::numeric_limits::max() - parcel1; - const bool needToPreventUnderflow = TypeIsSigned && value < std::numeric_limits::min() - parcel2; - - T newValue1 = T(value); - if (!needToPreventUnderflow) - newValue1 -= parcel1; - T newValue2 = T(value); - if (!needToPreventOverflow) - newValue2 -= parcel2; - - if (!needToPreventUnderflow) { QCOMPARE(atomic.fetchAndSubRelaxed(parcel1), T(value)); QCOMPARE(atomic.loadRelaxed(), newValue1); QCOMPARE(atomic.fetchAndSubRelaxed(parcel2), newValue1); - } QCOMPARE(atomic.loadRelaxed(), T(value)); - if (!needToPreventOverflow) { QCOMPARE(atomic.fetchAndSubRelaxed(parcel2), T(value)); QCOMPARE(atomic.loadRelaxed(), newValue2); QCOMPARE(atomic.fetchAndSubRelaxed(parcel1), newValue2); - } QCOMPARE(atomic.loadRelaxed(), T(value)); - if (!needToPreventUnderflow) { QCOMPARE(atomic.fetchAndSubAcquire(parcel1), T(value)); QCOMPARE(atomic.loadRelaxed(), newValue1); QCOMPARE(atomic.fetchAndSubAcquire(parcel2), newValue1); - } QCOMPARE(atomic.loadRelaxed(), T(value)); - if (!needToPreventOverflow) { QCOMPARE(atomic.fetchAndSubAcquire(parcel2), T(value)); QCOMPARE(atomic.loadRelaxed(), newValue2); QCOMPARE(atomic.fetchAndSubAcquire(parcel1), newValue2); - } QCOMPARE(atomic.loadRelaxed(), T(value)); - if (!needToPreventUnderflow) { QCOMPARE(atomic.fetchAndSubRelease(parcel1), T(value)); QCOMPARE(atomic.loadAcquire(), newValue1); QCOMPARE(atomic.fetchAndSubRelease(parcel2), newValue1); - } QCOMPARE(atomic.loadAcquire(), T(value)); - if (!needToPreventOverflow) { QCOMPARE(atomic.fetchAndSubRelease(parcel2), T(value)); QCOMPARE(atomic.loadAcquire(), newValue2); QCOMPARE(atomic.fetchAndSubRelease(parcel1), newValue2); - } QCOMPARE(atomic.loadAcquire(), T(value)); - if (!needToPreventUnderflow) { QCOMPARE(atomic.fetchAndSubOrdered(parcel1), T(value)); QCOMPARE(atomic.loadAcquire(), newValue1); QCOMPARE(atomic.fetchAndSubOrdered(parcel2), newValue1); - } QCOMPARE(atomic.loadAcquire(), T(value)); - if (!needToPreventOverflow) { QCOMPARE(atomic.fetchAndSubOrdered(parcel2), T(value)); QCOMPARE(atomic.loadAcquire(), newValue2); QCOMPARE(atomic.fetchAndSubOrdered(parcel1), newValue2); - } QCOMPARE(atomic.loadAcquire(), T(value)); // operator-= - if (!needToPreventUnderflow) { QCOMPARE(atomic -= parcel1, newValue1); QCOMPARE(atomic -= parcel2, T(value)); - } - if (!needToPreventOverflow) { QCOMPARE(atomic -= parcel2, newValue2); QCOMPARE(atomic -= parcel1, T(value)); - } } void tst_QAtomicIntegerXX::fetchAndOr()