[scudo] [GWP-ASan] Add GWP-ASan variant of scudo benchmarks.

[hctim]

Summary

GWP-ASan is the "production" variant as compiled by compiler-rt, and it's useful to be able to benchmark changes in GWP-ASan or Scudo's GWP-ASan hooks across versions. GWP-ASan is sampled, and sampled allocations are much slower, but given the amount of allocations that happen under test here - we actually get a reasonable representation of GWP-ASan's negligent performance impact between runs.

[hctim]

Forgot to update the once-init nonce. It needs to be moved to a member, rather than a global.

[hctim]

Forgot to initialize the global for the _loop variant.

[hctim]

friendly ping @cryptoad

[cryptoad]

compiler-rt/lib/scudo/standalone/benchmarks/malloc_benchmark.cpp

75

Probably include <vector>, I think on some platforms it's not inferred.

[hctim]

compiler-rt/lib/scudo/standalone/benchmarks/malloc_benchmark.cpp

75

(done in the commit)

compiler-rt/lib/scudo/standalone/benchmarks/CMakeLists.txt

 string(REPLACE ";" " " SCUDO_BENCHMARK_CFLAGS " ${SCUDO_BENCHMARK_CFLAGS}")
 
 foreach(arch ${SCUDO_STANDALONE_SUPPORTED_ARCH})
   add_benchmark(ScudoBenchmarks.${arch}
                 malloc_benchmark.cpp
                 $<TARGET_OBJECTS:RTScudoStandalone.${arch}>)
   set_property(TARGET ScudoBenchmarks.${arch} APPEND_STRING PROPERTY
                COMPILE_FLAGS "${SCUDO_BENCHMARK_CFLAGS}")
+
+  if (COMPILER_RT_HAS_GWP_ASAN)
+    add_benchmark(
+      ScudoBenchmarksWithGwpAsan.${arch} malloc_benchmark.cpp
+      $<TARGET_OBJECTS:RTScudoStandalone.${arch}>
+      $<TARGET_OBJECTS:RTGwpAsan.${arch}>
+      $<TARGET_OBJECTS:RTGwpAsanBacktraceLibc.${arch}>
+      $<TARGET_OBJECTS:RTGwpAsanSegvHandler.${arch}>)
+    set_property(
+      TARGET ScudoBenchmarksWithGwpAsan.${arch} APPEND_STRING PROPERTY
+      COMPILE_FLAGS "${SCUDO_BENCHMARK_CFLAGS} -DGWP_ASAN_HOOKS")
+  endif()
 endforeach()

compiler-rt/lib/scudo/standalone/benchmarks/malloc_benchmark.cpp

 //===-- malloc_benchmark.cpp ------------------------------------*- C++ -*-===//
 //
 // 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 "allocator_config.h"
 #include "combined.h"
 #include "common.h"
 
 #include "benchmark/benchmark.h"
 
 #include <memory>
 
+void *CurrentAllocator;
+template <typename Config> void PostInitCallback() {
+  reinterpret_cast<scudo::Allocator<Config> *>(CurrentAllocator)->initGwpAsan();
+}
+
 template <typename Config> static void BM_malloc_free(benchmark::State &State) {
-  using AllocatorT = scudo::Allocator<Config>;
+  using AllocatorT = scudo::Allocator<Config, PostInitCallback<Config>>;
   auto Deleter = [](AllocatorT *A) {
     A->unmapTestOnly();
     delete A;
   };
   std::unique_ptr<AllocatorT, decltype(Deleter)> Allocator(new AllocatorT,
                                                            Deleter);
+  CurrentAllocator = Allocator.get();
   Allocator->reset();
 
   const size_t NBytes = State.range(0);
   size_t PageSize = scudo::getPageSizeCached();
 
   for (auto _ : State) {
     void *Ptr = Allocator->allocate(NBytes, scudo::Chunk::Origin::Malloc);
     auto *Data = reinterpret_cast<uint8_t *>(Ptr);
BENCHMARK_TEMPLATE(BM_malloc_free, scudo::AndroidSvelteConfig)
     ->Range(MinSize, MaxSize);
 #if SCUDO_CAN_USE_PRIMARY64
 BENCHMARK_TEMPLATE(BM_malloc_free, scudo::FuchsiaConfig)
     ->Range(MinSize, MaxSize);
 #endif
 
 template <typename Config>
 static void BM_malloc_free_loop(benchmark::State &State) {
-  using AllocatorT = scudo::Allocator<Config>;
+  using AllocatorT = scudo::Allocator<Config, PostInitCallback<Config>>;
   auto Deleter = [](AllocatorT *A) {
     A->unmapTestOnly();
     delete A;
   };
   std::unique_ptr<AllocatorT, decltype(Deleter)> Allocator(new AllocatorT,
                                                            Deleter);
   Allocator->reset();
 
   const size_t NumIters = State.range(0);
   size_t PageSize = scudo::getPageSizeCached();
-  void *Ptrs[NumIters];
+  std::vector<void *> Ptrs(NumIters);
 
   for (auto _ : State) {
     size_t SizeLog2 = 0;
     for (void *&Ptr : Ptrs) {
       Ptr = Allocator->allocate(1 << SizeLog2, scudo::Chunk::Origin::Malloc);
       auto *Data = reinterpret_cast<uint8_t *>(Ptr);
       for (size_t I = 0; I < 1 << SizeLog2; I += PageSize)
         Data[I] = 1;

compiler-rt/lib/scudo/standalone/combined.h

 class Allocator {
 public:
   using PrimaryT = typename Params::Primary;
   using CacheT = typename PrimaryT::CacheT;
   typedef Allocator<Params, PostInitCallback> ThisT;
   typedef typename Params::template TSDRegistryT<ThisT> TSDRegistryT;
 
   void callPostInitCallback() {
-    static pthread_once_t OnceControl = PTHREAD_ONCE_INIT;
-    pthread_once(&OnceControl, PostInitCallback);
+    pthread_once(&PostInitNonce, PostInitCallback);
   }
 
   struct QuarantineCallback {
     explicit QuarantineCallback(ThisT &Instance, CacheT &LocalCache)
         : Allocator(Instance), Cache(LocalCache) {}
 
     // Chunk recycling function, returns a quarantined chunk to the backend,
     // first making sure it hasn't been tampered with.
private:
   u32 Cookie = 0;
   u32 QuarantineMaxChunkSize = 0;
 
   GlobalStats Stats;
   PrimaryT Primary;
   SecondaryT Secondary;
   QuarantineT Quarantine;
   TSDRegistryT TSDRegistry;
+  pthread_once_t PostInitNonce = PTHREAD_ONCE_INIT;
 
 #ifdef GWP_ASAN_HOOKS
   gwp_asan::GuardedPoolAllocator GuardedAlloc;
 #endif // GWP_ASAN_HOOKS
 
   StackDepot Depot;
 
   struct AllocationRingBuffer {