[libc++] Remove allocation.bench.cpp

[ldionne]

That benchmark isn't really useful, since it doesn't benchmark anything from libc++ (besides operator new). The implementation of the benchmark also has serious problems like the fact that it allocates an unknown amount of memory without deallocating it.

[llvmbot]

@llvm/pr-subscribers-libcxx

Author: Louis Dionne (ldionne)

Changes

That benchmark isn't really useful, since it doesn't benchmark anything from libc++ (besides operator new). The implementation of the benchmark also has serious problems like the fact that it allocates an unknown amount of memory without deallocating it.

---

Full diff: https://github.com/llvm/llvm-project/pull/120767.diff

1 Files Affected:

• (removed) libcxx/test/benchmarks/allocation.bench.cpp (-125)

diff --git a/libcxx/test/benchmarks/allocation.bench.cpp b/libcxx/test/benchmarks/allocation.bench.cpp
deleted file mode 100644
index bdccaa2c133bd7..00000000000000
--- a/libcxx/test/benchmarks/allocation.bench.cpp
+++ /dev/null
@@ -1,125 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-// UNSUPPORTED: c++03, c++11
-
-// These compiler versions and platforms don't enable sized deallocation by default.
-// ADDITIONAL_COMPILE_FLAGS(clang-17): -fsized-deallocation
-// ADDITIONAL_COMPILE_FLAGS(clang-18): -fsized-deallocation
-// ADDITIONAL_COMPILE_FLAGS(apple-clang-15): -fsized-deallocation
-// ADDITIONAL_COMPILE_FLAGS(apple-clang-16): -fsized-deallocation
-// ADDITIONAL_COMPILE_FLAGS(target=x86_64-w64-windows-gnu): -fsized-deallocation
-// ADDITIONAL_COMPILE_FLAGS(target=i686-w64-windows-gnu): -fsized-deallocation
-
-#include "benchmark/benchmark.h"
-
-#include <cassert>
-#include <cstdlib>
-#include <new>
-#include <vector>
-
-#include "test_macros.h"
-
-struct PointerList {
-  PointerList* Next = nullptr;
-};
-
-struct MallocWrapper {
-  __attribute__((always_inline)) static void* Allocate(size_t N) { return std::malloc(N); }
-  __attribute__((always_inline)) static void Deallocate(void* P, size_t) { std::free(P); }
-};
-
-struct NewWrapper {
-  __attribute__((always_inline)) static void* Allocate(size_t N) { return ::operator new(N); }
-  __attribute__((always_inline)) static void Deallocate(void* P, size_t) { ::operator delete(P); }
-};
-
-#ifdef TEST_COMPILER_CLANG
-struct BuiltinNewWrapper {
-  __attribute__((always_inline)) static void* Allocate(size_t N) { return __builtin_operator_new(N); }
-  __attribute__((always_inline)) static void Deallocate(void* P, size_t) { __builtin_operator_delete(P); }
-};
-
-struct BuiltinSizedNewWrapper {
-  __attribute__((always_inline)) static void* Allocate(size_t N) { return __builtin_operator_new(N); }
-  __attribute__((always_inline)) static void Deallocate(void* P, size_t N) { __builtin_operator_delete(P, N); }
-};
-#endif
-
-template <class AllocWrapper>
-static void BM_AllocateAndDeallocate(benchmark::State& st) {
-  const size_t alloc_size = st.range(0);
-  while (st.KeepRunning()) {
-    void* p = AllocWrapper::Allocate(alloc_size);
-    benchmark::DoNotOptimize(p);
-    AllocWrapper::Deallocate(p, alloc_size);
-  }
-}
-
-template <class AllocWrapper>
-static void BM_AllocateOnly(benchmark::State& st) {
-  const size_t alloc_size = st.range(0);
-  PointerList* Start      = nullptr;
-
-  while (st.KeepRunning()) {
-    PointerList* p = (PointerList*)AllocWrapper::Allocate(alloc_size);
-    benchmark::DoNotOptimize(p);
-    p->Next = Start;
-    Start   = p;
-  }
-
-  PointerList* Next = Start;
-  while (Next) {
-    PointerList* Tmp = Next;
-    Next             = Tmp->Next;
-    AllocWrapper::Deallocate(Tmp, alloc_size);
-  }
-}
-
-template <class AllocWrapper>
-static void BM_DeallocateOnly(benchmark::State& st) {
-  const size_t alloc_size = st.range(0);
-  const auto NumAllocs    = st.max_iterations;
-
-  std::vector<void*> Pointers(NumAllocs);
-  for (auto& p : Pointers) {
-    p = AllocWrapper::Allocate(alloc_size);
-  }
-
-  void** Data                       = Pointers.data();
-  [[maybe_unused]] void** const End = Pointers.data() + Pointers.size();
-  while (st.KeepRunning()) {
-    AllocWrapper::Deallocate(*Data, alloc_size);
-    Data += 1;
-  }
-  assert(Data == End);
-}
-
-static int RegisterAllocBenchmarks() {
-  using FnType = void (*)(benchmark::State&);
-  struct {
-    const char* name;
-    FnType func;
-  } TestCases[] = {
-      {"BM_Malloc", &BM_AllocateAndDeallocate<MallocWrapper>},
-      {"BM_New", &BM_AllocateAndDeallocate<NewWrapper>},
-#ifdef TEST_COMPILER_CLANG
-      {"BM_BuiltinNewDelete", BM_AllocateAndDeallocate<BuiltinNewWrapper>},
-      {"BM_BuiltinSizedNewDelete", BM_AllocateAndDeallocate<BuiltinSizedNewWrapper>},
-      {"BM_BuiltinNewAllocateOnly", BM_AllocateOnly<BuiltinSizedNewWrapper>},
-      {"BM_BuiltinNewSizedDeallocateOnly", BM_DeallocateOnly<BuiltinSizedNewWrapper>},
-#endif
-  };
-  for (auto TC : TestCases) {
-    benchmark::RegisterBenchmark(TC.name, TC.func)->Range(16, 4096 * 2);
-  }
-  return 0;
-}
-int Sink = RegisterAllocBenchmarks();
-
-BENCHMARK_MAIN();