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//===-- Benchmark memory specific tools -----------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "LibcMemoryBenchmark.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include <algorithm>
namespace llvm {
namespace libc_benchmarks {
// Returns a distribution that samples the buffer to satisfy the required
// alignment.
// When alignment is set, the distribution is scaled down by `Factor` and scaled
// up again by the same amount during sampling.
static std::uniform_int_distribution<uint32_t>
GetOffsetDistribution(const StudyConfiguration &Conf) {
if (Conf.AddressAlignment &&
*Conf.AddressAlignment > AlignedBuffer::Alignment)
report_fatal_error(
"AddressAlignment must be less or equal to AlignedBuffer::Alignment");
if (!Conf.AddressAlignment)
return std::uniform_int_distribution<uint32_t>(0, 0); // Always 0.
// If we test up to Size bytes, the returned offset must stay under
// BuffersSize - Size.
int64_t MaxOffset = Conf.BufferSize;
MaxOffset -= Conf.Size.To;
MaxOffset -= 1;
if (MaxOffset < 0)
report_fatal_error(
"BufferSize too small to exercise specified Size configuration");
MaxOffset /= Conf.AddressAlignment->value();
return std::uniform_int_distribution<uint32_t>(0, MaxOffset);
}
OffsetDistribution::OffsetDistribution(const StudyConfiguration &Conf)
: Distribution(GetOffsetDistribution(Conf)),
Factor(Conf.AddressAlignment.valueOrOne().value()) {}
// Precomputes offset where to insert mismatches between the two buffers.
MismatchOffsetDistribution::MismatchOffsetDistribution(
const StudyConfiguration &Conf)
: MismatchAt(Conf.MemcmpMismatchAt) {
if (MismatchAt <= 1)
return;
const auto ToSize = Conf.Size.To;
for (size_t I = ToSize + 1; I < Conf.BufferSize; I += ToSize)
MismatchIndices.push_back(I);
if (MismatchIndices.empty())
llvm::report_fatal_error("Unable to generate mismatch");
MismatchIndexSelector =
std::uniform_int_distribution<size_t>(0, MismatchIndices.size() - 1);
}
} // namespace libc_benchmarks
} // namespace llvm
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