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//===-- Benchmark memcmp implementation -----------------------------------===//
//
// 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 "LibcBenchmark.h"
#include "LibcMemoryBenchmark.h"
#include "LibcMemoryBenchmarkMain.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Support/raw_ostream.h"
namespace llvm {
namespace libc_benchmarks {
// The context encapsulates the buffers, parameters and the measure.
struct MemcmpContext : public BenchmarkRunner {
using FunctionPrototype = int (*)(const void *, const void *, size_t);
struct ParameterType {
uint16_t Offset = 0;
};
explicit MemcmpContext(const StudyConfiguration &Conf)
: MOD(Conf), OD(Conf), ABuffer(Conf.BufferSize), BBuffer(Conf.BufferSize),
PP(*this) {
std::uniform_int_distribution<char> Dis;
// Generate random buffer A.
for (size_t I = 0; I < Conf.BufferSize; ++I)
ABuffer[I] = Dis(Gen);
// Copy buffer A to B.
::memcpy(BBuffer.begin(), ABuffer.begin(), Conf.BufferSize);
if (Conf.MemcmpMismatchAt == 0)
return; // all same.
else if (Conf.MemcmpMismatchAt == 1)
for (char &c : BBuffer)
++c; // all different.
else
for (const auto I : MOD.getMismatchIndices())
++BBuffer[I];
}
// Needed by the ParameterProvider to update the current batch of parameter.
void Randomize(MutableArrayRef<ParameterType> Parameters) {
if (MOD)
for (auto &P : Parameters)
P.Offset = MOD(Gen, CurrentSize);
else
for (auto &P : Parameters)
P.Offset = OD(Gen);
}
ArrayRef<StringRef> getFunctionNames() const override {
static std::array<StringRef, 1> kFunctionNames = {"memcmp"};
return kFunctionNames;
}
BenchmarkResult benchmark(const BenchmarkOptions &Options,
StringRef FunctionName, size_t Size) override {
CurrentSize = Size;
// FIXME: Add `bcmp` once we're guaranteed that the function is provided.
FunctionPrototype Function =
StringSwitch<FunctionPrototype>(FunctionName).Case("memcmp", &::memcmp);
return llvm::libc_benchmarks::benchmark(
Options, PP, [this, Function, Size](ParameterType p) {
return Function(ABuffer + p.Offset, BBuffer + p.Offset, Size);
});
}
private:
std::default_random_engine Gen;
MismatchOffsetDistribution MOD;
OffsetDistribution OD;
size_t CurrentSize = 0;
AlignedBuffer ABuffer;
AlignedBuffer BBuffer;
SmallParameterProvider<MemcmpContext> PP;
};
std::unique_ptr<BenchmarkRunner> getRunner(const StudyConfiguration &Conf) {
return std::make_unique<MemcmpContext>(Conf);
}
} // namespace libc_benchmarks
} // namespace llvm
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