[compiler-rt] Replace deprecated aligned_storage with aligned byte array (#94171)

`std::aligned_storage` is deprecated with C++23, see
[here](https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p1413r3.pdf).

This replaces the usages of `std::aligned_storage` within compiler-rt
with an aligned `std::byte` array.
I will provide patches for other subcomponents as well.

compiler-rt/lib/xray/tests/unit/function_call_trie_test.cpp

@@ -310,16 +310,14 @@ TEST(FunctionCallTrieTest, MergeInto) {
 
 TEST(FunctionCallTrieTest, PlacementNewOnAlignedStorage) {
   profilingFlags()->setDefaults();
-  typename std::aligned_storage<sizeof(FunctionCallTrie::Allocators),
-                                alignof(FunctionCallTrie::Allocators)>::type
-      AllocatorsStorage;
+  alignas(FunctionCallTrie::Allocators)
+      std::byte AllocatorsStorage[sizeof(FunctionCallTrie::Allocators)];
   new (&AllocatorsStorage)
       FunctionCallTrie::Allocators(FunctionCallTrie::InitAllocators());
   auto *A =
       reinterpret_cast<FunctionCallTrie::Allocators *>(&AllocatorsStorage);
 
-  typename std::aligned_storage<sizeof(FunctionCallTrie),
-                                alignof(FunctionCallTrie)>::type FCTStorage;
+  alignas(FunctionCallTrie) std::byte FCTStorage[sizeof(FunctionCallTrie)];
   new (&FCTStorage) FunctionCallTrie(*A);
   auto *T = reinterpret_cast<FunctionCallTrie *>(&FCTStorage);
 

compiler-rt/lib/xray/tests/unit/profile_collector_test.cpp

@@ -38,8 +38,8 @@ struct ExpectedProfilingFileHeader {
 void ValidateFileHeaderBlock(XRayBuffer B) {
   ASSERT_NE(static_cast<const void *>(B.Data), nullptr);
   ASSERT_EQ(B.Size, sizeof(ExpectedProfilingFileHeader));
-  typename std::aligned_storage<sizeof(ExpectedProfilingFileHeader)>::type
-      FileHeaderStorage;
+  alignas(ExpectedProfilingFileHeader)
+      std::byte FileHeaderStorage[sizeof(ExpectedProfilingFileHeader)];
   ExpectedProfilingFileHeader ExpectedHeader;
   std::memcpy(&FileHeaderStorage, B.Data, B.Size);
   auto &FileHeader =

compiler-rt/lib/xray/tests/unit/segmented_array_test.cpp

@@ -226,13 +226,11 @@ TEST(SegmentedArrayTest, SimulateStackBehaviour) {
 
 TEST(SegmentedArrayTest, PlacementNewOnAlignedStorage) {
   using AllocatorType = typename Array<ShadowStackEntry>::AllocatorType;
-  typename std::aligned_storage<sizeof(AllocatorType),
-                                alignof(AllocatorType)>::type AllocatorStorage;
+  alignas(AllocatorType) std::byte AllocatorStorage[sizeof(AllocatorType)];
   new (&AllocatorStorage) AllocatorType(1 << 10);
   auto *A = reinterpret_cast<AllocatorType *>(&AllocatorStorage);
-  typename std::aligned_storage<sizeof(Array<ShadowStackEntry>),
-                                alignof(Array<ShadowStackEntry>)>::type
-      ArrayStorage;
+  alignas(Array<ShadowStackEntry>)
+      std::byte ArrayStorage[sizeof(Array<ShadowStackEntry>)];
   new (&ArrayStorage) Array<ShadowStackEntry>(*A);
   auto *Data = reinterpret_cast<Array<ShadowStackEntry> *>(&ArrayStorage);
 

compiler-rt/lib/xray/tests/unit/test_helpers.cpp

@@ -69,8 +69,7 @@ namespace __xray {
 
 std::string serialize(BufferQueue &Buffers, int32_t Version) {
   std::string Serialized;
-  std::aligned_storage<sizeof(XRayFileHeader), alignof(XRayFileHeader)>::type
-      HeaderStorage;
+  alignas(XRayFileHeader) std::byte HeaderStorage[sizeof(XRayFileHeader)];
   auto *Header = reinterpret_cast<XRayFileHeader *>(&HeaderStorage);
   new (Header) XRayFileHeader();
   Header->Version = Version;

compiler-rt/lib/xray/xray_fdr_logging.cpp

@@ -55,17 +55,12 @@ struct XRAY_TLS_ALIGNAS(64) ThreadLocalData {
   BufferQueue::Buffer Buffer{};
   BufferQueue *BQ = nullptr;
 
-  using LogWriterStorage =
-      typename std::aligned_storage<sizeof(FDRLogWriter),
-                                    alignof(FDRLogWriter)>::type;
-
-  LogWriterStorage LWStorage;
+  using LogWriterStorage = std::byte[sizeof(FDRLogWriter)];
+  alignas(FDRLogWriter) LogWriterStorage LWStorage;
   FDRLogWriter *Writer = nullptr;
 
-  using ControllerStorage =
-      typename std::aligned_storage<sizeof(FDRController<>),
-                                    alignof(FDRController<>)>::type;
-  ControllerStorage CStorage;
+  using ControllerStorage = std::byte[sizeof(FDRController<>)];
+  alignas(FDRController<>) ControllerStorage CStorage;
   FDRController<> *Controller = nullptr;
 };
 
@@ -78,7 +73,7 @@ static_assert(std::is_trivially_destructible<ThreadLocalData>::value,
 static pthread_key_t Key;
 
 // Global BufferQueue.
-static std::aligned_storage<sizeof(BufferQueue)>::type BufferQueueStorage;
+static std::byte BufferQueueStorage[sizeof(BufferQueue)];
 static BufferQueue *BQ = nullptr;
 
 // Global thresholds for function durations.
@@ -129,8 +124,8 @@ static_assert(alignof(ThreadLocalData) >= 64,
               "ThreadLocalData must be cache line aligned.");
 #endif
 static ThreadLocalData &getThreadLocalData() {
-  thread_local typename std::aligned_storage<
-      sizeof(ThreadLocalData), alignof(ThreadLocalData)>::type TLDStorage{};
+  alignas(ThreadLocalData) thread_local std::byte
+      TLDStorage[sizeof(ThreadLocalData)];
 
   if (pthread_getspecific(Key) == NULL) {
     new (reinterpret_cast<ThreadLocalData *>(&TLDStorage)) ThreadLocalData{};

compiler-rt/lib/xray/xray_function_call_trie.h

@@ -139,18 +139,14 @@ public:
 
     // Use hosted aligned storage members to allow for trivial move and init.
     // This also allows us to sidestep the potential-failing allocation issue.
-    typename std::aligned_storage<sizeof(NodeAllocatorType),
-                                  alignof(NodeAllocatorType)>::type
-        NodeAllocatorStorage;
-    typename std::aligned_storage<sizeof(RootAllocatorType),
-                                  alignof(RootAllocatorType)>::type
-        RootAllocatorStorage;
-    typename std::aligned_storage<sizeof(ShadowStackAllocatorType),
-                                  alignof(ShadowStackAllocatorType)>::type
-        ShadowStackAllocatorStorage;
-    typename std::aligned_storage<sizeof(NodeIdPairAllocatorType),
-                                  alignof(NodeIdPairAllocatorType)>::type
-        NodeIdPairAllocatorStorage;
+    alignas(NodeAllocatorType) std::byte
+        NodeAllocatorStorage[sizeof(NodeAllocatorType)];
+    alignas(RootAllocatorType) std::byte
+        RootAllocatorStorage[sizeof(RootAllocatorType)];
+    alignas(ShadowStackAllocatorType) std::byte
+        ShadowStackAllocatorStorage[sizeof(ShadowStackAllocatorType)];
+    alignas(NodeIdPairAllocatorType) std::byte
+        NodeIdPairAllocatorStorage[sizeof(NodeIdPairAllocatorType)];
 
     NodeAllocatorType *NodeAllocator = nullptr;
     RootAllocatorType *RootAllocator = nullptr;

compiler-rt/lib/xray/xray_profile_collector.cpp

@@ -29,7 +29,7 @@ namespace {
 SpinMutex GlobalMutex;
 struct ThreadTrie {
   tid_t TId;
-  typename std::aligned_storage<sizeof(FunctionCallTrie)>::type TrieStorage;
+  alignas(FunctionCallTrie) std::byte TrieStorage[sizeof(FunctionCallTrie)];
 };
 
 struct ProfileBuffer {
@@ -71,16 +71,13 @@ using ThreadDataAllocator = ThreadDataArray::AllocatorType;
 // by the ThreadData array. This lets us host the buffers, allocators, and tries
 // associated with a thread by moving the data into the array instead of
 // attempting to copy the data to a separately backed set of tries.
-static typename std::aligned_storage<
-    sizeof(BufferQueue), alignof(BufferQueue)>::type BufferQueueStorage;
+alignas(BufferQueue) static std::byte BufferQueueStorage[sizeof(BufferQueue)];
 static BufferQueue *BQ = nullptr;
 static BufferQueue::Buffer Buffer;
-static typename std::aligned_storage<sizeof(ThreadDataAllocator),
-                                     alignof(ThreadDataAllocator)>::type
-    ThreadDataAllocatorStorage;
-static typename std::aligned_storage<sizeof(ThreadDataArray),
-                                     alignof(ThreadDataArray)>::type
-    ThreadDataArrayStorage;
+alignas(ThreadDataAllocator) static std::byte
+    ThreadDataAllocatorStorage[sizeof(ThreadDataAllocator)];
+alignas(ThreadDataArray) static std::byte
+    ThreadDataArrayStorage[sizeof(ThreadDataArray)];
 
 static ThreadDataAllocator *TDAllocator = nullptr;
 static ThreadDataArray *TDArray = nullptr;
@@ -91,10 +88,10 @@ using ProfileBufferArrayAllocator = typename ProfileBufferArray::AllocatorType;
 // These need to be global aligned storage to avoid dynamic initialization. We
 // need these to be aligned to allow us to placement new objects into the
 // storage, and have pointers to those objects be appropriately aligned.
-static typename std::aligned_storage<sizeof(ProfileBufferArray)>::type
-    ProfileBuffersStorage;
-static typename std::aligned_storage<sizeof(ProfileBufferArrayAllocator)>::type
-    ProfileBufferArrayAllocatorStorage;
+alignas(ProfileBufferArray) static std::byte
+    ProfileBuffersStorage[sizeof(ProfileBufferArray)];
+alignas(ProfileBufferArrayAllocator) static std::byte
+    ProfileBufferArrayAllocatorStorage[sizeof(ProfileBufferArrayAllocator)];
 
 static ProfileBufferArrayAllocator *ProfileBuffersAllocator = nullptr;
 static ProfileBufferArray *ProfileBuffers = nullptr;
@@ -382,8 +379,8 @@ XRayBuffer nextBuffer(XRayBuffer B) XRAY_NEVER_INSTRUMENT {
     return {nullptr, 0};
 
   static pthread_once_t Once = PTHREAD_ONCE_INIT;
-  static typename std::aligned_storage<sizeof(XRayProfilingFileHeader)>::type
-      FileHeaderStorage;
+  alignas(XRayProfilingFileHeader) static std::byte
+      FileHeaderStorage[sizeof(XRayProfilingFileHeader)];
   pthread_once(
       &Once, +[]() XRAY_NEVER_INSTRUMENT {
         new (&FileHeaderStorage) XRayProfilingFileHeader{};

compiler-rt/lib/xray/xray_profiling.cpp

@@ -48,17 +48,14 @@ static pthread_key_t ProfilingKey;
 
 // We use a global buffer queue, which gets initialized once at initialisation
 // time, and gets reset when profiling is "done".
-static std::aligned_storage<sizeof(BufferQueue), alignof(BufferQueue)>::type
-    BufferQueueStorage;
+alignas(BufferQueue) static std::byte BufferQueueStorage[sizeof(BufferQueue)];
 static BufferQueue *BQ = nullptr;
 
 thread_local FunctionCallTrie::Allocators::Buffers ThreadBuffers;
-thread_local std::aligned_storage<sizeof(FunctionCallTrie::Allocators),
-                                  alignof(FunctionCallTrie::Allocators)>::type
-    AllocatorsStorage;
-thread_local std::aligned_storage<sizeof(FunctionCallTrie),
-                                  alignof(FunctionCallTrie)>::type
-    FunctionCallTrieStorage;
+alignas(FunctionCallTrie::Allocators) thread_local std::byte
+    AllocatorsStorage[sizeof(FunctionCallTrie::Allocators)];
+alignas(FunctionCallTrie) thread_local std::byte
+    FunctionCallTrieStorage[sizeof(FunctionCallTrie)];
 thread_local ProfilingData TLD{{0}, {0}};
 thread_local atomic_uint8_t ReentranceGuard{0};
 

compiler-rt/lib/xray/xray_segmented_array.h

@@ -56,8 +56,7 @@ public:
   //     kCacheLineSize-multiple segments, minus the size of two pointers.
   //
   //   - Request cacheline-multiple sized elements from the allocator.
-  static constexpr uint64_t AlignedElementStorageSize =
-      sizeof(typename std::aligned_storage<sizeof(T), alignof(T)>::type);
+  static constexpr uint64_t AlignedElementStorageSize = sizeof(T);
 
   static constexpr uint64_t SegmentControlBlockSize = sizeof(Segment *) * 2;
 

compiler-rt/test/tsan/custom_mutex4.cpp

@@ -1,7 +1,7 @@
-// RUN: %clangxx_tsan -O1 --std=c++11 %s -o %t && %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_tsan -O1 --std=c++17 %s -o %t && %run %t 2>&1 | FileCheck %s
 #include "custom_mutex.h"
 
-#include <type_traits>
+#include <cstddef>
 
 // Test that the destruction events of a mutex are ignored when the
 // annotations request this.
@@ -12,14 +12,14 @@
 // has run.
 
 int main() {
-  std::aligned_storage<sizeof(Mutex), alignof(Mutex)>::type mu1_store;
+  alignas(Mutex) std::byte mu1_store[sizeof(Mutex)];
   Mutex* mu1 = reinterpret_cast<Mutex*>(&mu1_store);
   new(&mu1_store) Mutex(false, __tsan_mutex_linker_init);
   mu1->Lock();
   mu1->~Mutex();
   mu1->Unlock();
 
-  std::aligned_storage<sizeof(Mutex), alignof(Mutex)>::type mu2_store;
+  alignas(Mutex) std::byte mu2_store[sizeof(Mutex)];
   Mutex* mu2 = reinterpret_cast<Mutex*>(&mu2_store);
   new(&mu2_store) Mutex(false, 0, __tsan_mutex_not_static);
   mu2->Lock();

compiler-rt/test/tsan/custom_mutex5.cpp

@@ -1,20 +1,20 @@
-// RUN: %clangxx_tsan -O1 --std=c++11 %s -o %t && %deflake %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_tsan -O1 --std=c++17 %s -o %t && %deflake %run %t 2>&1 | FileCheck %s
 #include "custom_mutex.h"
 
-#include <type_traits>
+#include <cstddef>
 
 // Test that we detect the destruction of an in-use mutex when the
 // thread annotations don't otherwise disable the check.
 
 int main() {
-  std::aligned_storage<sizeof(Mutex), alignof(Mutex)>::type mu1_store;
+  alignas(Mutex) std::byte mu1_store[sizeof(Mutex)];
   Mutex* mu1 = reinterpret_cast<Mutex*>(&mu1_store);
   new(&mu1_store) Mutex(false, 0);
   mu1->Lock();
   mu1->~Mutex();
   mu1->Unlock();
 
-  std::aligned_storage<sizeof(Mutex), alignof(Mutex)>::type mu2_store;
+  alignas(Mutex) std::byte mu2_store[sizeof(Mutex)];
   Mutex* mu2 = reinterpret_cast<Mutex*>(&mu2_store);
   new(&mu2_store)
       Mutex(false, __tsan_mutex_not_static, __tsan_mutex_not_static);