Make sure DefaultAllocator and SingleFrameAllocator returned 16-bytes aligned memory

CHANGELOG.md

@@ -6,6 +6,9 @@
 
 ### Changed
 
+ - The library must now be compiled with C++ 17 compiler
+ - If the user sets its custom allocator, the return allocated memory must now be 16 bytes aligned
+
 ### Removed
 
 ### Fixed

CMakeLists.txt

@@ -1,5 +1,5 @@
 # Minimum cmake version required
-cmake_minimum_required(VERSION 3.8)
+cmake_minimum_required(VERSION 3.10)
 
 # Project configuration
 project(ReactPhysics3D VERSION 0.9.0 LANGUAGES CXX)
@@ -242,7 +242,7 @@ add_library(reactphysics3d ${REACTPHYSICS3D_HEADERS} ${REACTPHYSICS3D_SOURCES})
 add_library(ReactPhysics3D::reactphysics3d ALIAS reactphysics3d)
 
 # C++11 compiler features
-target_compile_features(reactphysics3d PUBLIC cxx_std_11)
+target_compile_features(reactphysics3d PUBLIC cxx_std_17)
 set_target_properties(reactphysics3d PROPERTIES CXX_EXTENSIONS OFF)
 
 # Library headers

include/reactphysics3d/configuration.h

@@ -129,6 +129,9 @@ constexpr uint16 NB_MAX_CONTACT_POINTS_IN_POTENTIAL_MANIFOLD = 256;
 /// Distance threshold to consider that two contact points in a manifold are the same
 constexpr decimal SAME_CONTACT_POINT_DISTANCE_THRESHOLD = decimal(0.01);
 
+/// Global alignment (in bytes) that all allocators must enforce
+constexpr uint8 GLOBAL_ALIGNMENT = 16;
+
 /// Current version of ReactPhysics3D
 const std::string RP3D_VERSION = std::string("0.9.0");
 

include/reactphysics3d/memory/DefaultAllocator.h

@@ -28,15 +28,19 @@
 
 // Libraries
 #include <reactphysics3d/memory/MemoryAllocator.h>
+#include <reactphysics3d/configuration.h>
 #include <cstdlib>
 #include <iostream>
+#include <stdlib.h>
 
 /// ReactPhysics3D namespace
 namespace reactphysics3d {
 
 // Class DefaultAllocator
 /**
- * This class represents a default memory allocator that uses default malloc/free methods
+ * This class represents a default memory allocator that uses standard C++ functions
+ * to allocated 16-bytes aligned memory.
+ *
  */
 class DefaultAllocator : public MemoryAllocator {
 
@@ -49,15 +53,33 @@ class DefaultAllocator : public MemoryAllocator {
         DefaultAllocator& operator=(DefaultAllocator& allocator) = default;
 
         /// Allocate memory of a given size (in bytes) and return a pointer to the
-        /// allocated memory.
+        /// allocated memory. The returned allocated memory must be 16 bytes aligned.
         virtual void* allocate(size_t size) override {
 
-            return std::malloc(size);
+// If compiler is Visual Studio
+#ifdef _MSC_VER
+
+                // Visual Studio doesn't not support standard std:aligned_alloc() method from c++ 17
+                return _alligned_malloc(size, GLOBAL_ALIGNMENT);
+#else
+
+                // Return 16-bytes aligned memory
+                return std::aligned_alloc(GLOBAL_ALIGNMENT, size);
+#endif
         }
 
         /// Release previously allocated memory.
         virtual void release(void* pointer, size_t /*size*/) override {
-            std::free(pointer);
+
+            // If compiler is Visual Studio
+#ifdef _MSC_VER
+
+                // Visual Studio doesn't not support standard std:aligned_alloc() method from c++ 17
+                return _aligned_free(GLOBAL_ALIGNMENT, pointer);
+#else
+
+                return std::free(pointer);
+#endif
         }
 };
 

include/reactphysics3d/memory/MemoryAllocator.h

@@ -50,7 +50,7 @@ class MemoryAllocator {
         MemoryAllocator& operator=(MemoryAllocator& allocator) = default;
 
         /// Allocate memory of a given size (in bytes) and return a pointer to the
-        /// allocated memory.
+        /// allocated memory. The return allocated memory must be 16 bytes aligned.
         virtual void* allocate(size_t size)=0;
 
         /// Release previously allocated memory.

include/reactphysics3d/memory/MemoryManager.h

@@ -104,14 +104,18 @@ class MemoryManager {
 // Allocate memory of a given type
 RP3D_FORCE_INLINE void* MemoryManager::allocate(AllocationType allocationType, size_t size) {
 
+    void* allocatedMemory = nullptr;
+
     switch (allocationType) {
-       case AllocationType::Base: return mBaseAllocator->allocate(size);
-       case AllocationType::Pool: return mPoolAllocator.allocate(size);
-       case AllocationType::Heap: return mHeapAllocator.allocate(size);
-       case AllocationType::Frame: return mSingleFrameAllocator.allocate(size);
+       case AllocationType::Base: allocatedMemory = mBaseAllocator->allocate(size); break;
+       case AllocationType::Pool: allocatedMemory =  mPoolAllocator.allocate(size); break;
+       case AllocationType::Heap: allocatedMemory =  mHeapAllocator.allocate(size); break;
+       case AllocationType::Frame: allocatedMemory =  mSingleFrameAllocator.allocate(size); break;
     }
 
-    return nullptr;
+    assert(allocatedMemory == nullptr || reinterpret_cast<uintptr_t>(allocatedMemory) % 16 == 0);
+
+    return allocatedMemory;
 }
 
 // Release previously allocated memory.

include/reactphysics3d/memory/PoolAllocator.h

@@ -81,13 +81,16 @@ class PoolAllocator : public MemoryAllocator {
         /// Number of heaps
         static const int NB_HEAPS = 128;
 
+        /// Minimum unit size
+        static const size_t MIN_UNIT_SIZE = 16;
+
         /// Maximum memory unit size. An allocation request of a size smaller or equal to
         /// this size will be handled using the small block allocator. However, for an
         /// allocation request larger than the maximum block size, the standard malloc()
         /// will be used.
-        static const size_t MAX_UNIT_SIZE = 1024;
+        static const size_t MAX_UNIT_SIZE = NB_HEAPS * MIN_UNIT_SIZE;
 
-        /// Size a memory chunk
+        /// Size of a memory chunk
         static const size_t BLOCK_SIZE = 16 * MAX_UNIT_SIZE;
 
         // -------------------- Attributes -------------------- //

include/reactphysics3d/memory/SingleFrameAllocator.h

@@ -45,10 +45,6 @@ class SingleFrameAllocator : public MemoryAllocator {
 
         // -------------------- Constants -------------------- //
 
-        /// Number of frames to wait before shrinking the allocated
-        /// memory if too much is allocated
-        static const int NB_FRAMES_UNTIL_SHRINK = 120;
-
         /// Initial size (in bytes) of the single frame allocator
         size_t INIT_SINGLE_FRAME_ALLOCATOR_NB_BYTES = 1048576; // 1Mb
 
@@ -69,13 +65,6 @@ class SingleFrameAllocator : public MemoryAllocator {
         /// Pointer to the next available memory location in the buffer
         size_t mCurrentOffset;
 
-        /// Current number of frames since we detected too much memory
-        /// is allocated
-        size_t mNbFramesTooMuchAllocated;
-
-        /// True if we need to allocate more memory in the next reset() call
-        bool mNeedToAllocatedMore;
-
     public :
 
         // -------------------- Methods -------------------- //

src/memory/HeapAllocator.cpp

@@ -175,7 +175,12 @@ void* HeapAllocator::allocate(size_t size) {
     }
 
     // Return a pointer to the memory area inside the unit
-    return static_cast<void*>(reinterpret_cast<unsigned char*>(currentUnit) + sizeof(MemoryUnitHeader));
+    void* allocatedMemory = static_cast<void*>(reinterpret_cast<unsigned char*>(currentUnit) + sizeof(MemoryUnitHeader));
+
+    // Check that allocated memory is 16-bytes aligned
+    assert(reinterpret_cast<uintptr_t>(allocatedMemory) % GLOBAL_ALIGNMENT == 0);
+
+    return allocatedMemory;
 }
 
 // Release previously allocated memory.
@@ -251,6 +256,9 @@ void HeapAllocator::reserve(size_t sizeToAllocate) {
     void* memory = mBaseAllocator.allocate(sizeToAllocate + sizeof(MemoryUnitHeader));
     assert(memory != nullptr);
 
+    // Check that allocated memory is 16-bytes aligned
+    assert(reinterpret_cast<uintptr_t>(memory) % GLOBAL_ALIGNMENT == 0);
+
     // Create a new memory unit for the allocated memory
     MemoryUnitHeader* memoryUnit = new (memory) MemoryUnitHeader(sizeToAllocate, nullptr, mMemoryUnits, false);
 

src/memory/PoolAllocator.cpp

@@ -57,7 +57,7 @@ PoolAllocator::PoolAllocator(MemoryAllocator& baseAllocator) : mBaseAllocator(ba
         // Initialize the array that contains the sizes of the memory units that will
         // be allocated in each different heap
         for (uint i=0; i < NB_HEAPS; i++) {
-            mUnitSizes[i] = (i+1) * 8;
+            mUnitSizes[i] = (i+1) * MIN_UNIT_SIZE;
         }
 
         // Initialize the lookup table that maps the size to allocated to the
@@ -116,7 +116,12 @@ void* PoolAllocator::allocate(size_t size) {
     if (size > MAX_UNIT_SIZE) {
 
         // Allocate memory using default allocation
-        return mBaseAllocator.allocate(size);
+        void* allocatedMemory = mBaseAllocator.allocate(size);
+
+        // Check that allocated memory is 16-bytes aligned
+        assert(reinterpret_cast<uintptr_t>(allocatedMemory) % GLOBAL_ALIGNMENT == 0);
+
+        return allocatedMemory;
     }
 
     // Get the index of the heap that will take care of the allocation request
@@ -129,7 +134,13 @@ void* PoolAllocator::allocate(size_t size) {
         // Return a pointer to the memory unit
         MemoryUnit* unit = mFreeMemoryUnits[indexHeap];
         mFreeMemoryUnits[indexHeap] = unit->nextUnit;
-        return unit;
+
+        void* allocatedMemory = static_cast<void*>(unit);
+
+        // Check that allocated memory is 16-bytes aligned
+        assert(reinterpret_cast<uintptr_t>(allocatedMemory) % GLOBAL_ALIGNMENT == 0);
+
+        return allocatedMemory;
     }
     else {  // If there is no more free memory units in the corresponding heap
 
@@ -170,8 +181,13 @@ void* PoolAllocator::allocate(size_t size) {
         mFreeMemoryUnits[indexHeap] = newBlock->memoryUnits->nextUnit;
         mNbCurrentMemoryBlocks++;
 
+        void* allocatedMemory = newBlock->memoryUnits;
+
+        // Check that allocated memory is 16-bytes aligned
+        assert(reinterpret_cast<uintptr_t>(allocatedMemory) % GLOBAL_ALIGNMENT == 0);
+
         // Return the pointer to the first memory unit of the new allocated block
-        return newBlock->memoryUnits;
+        return allocatedMemory;
     }
 }
 

src/memory/SingleFrameAllocator.cpp

@@ -34,7 +34,7 @@ using namespace reactphysics3d;
 // Constructor
 SingleFrameAllocator::SingleFrameAllocator(MemoryAllocator& baseAllocator) : mBaseAllocator(baseAllocator),
                                            mTotalSizeBytes(INIT_SINGLE_FRAME_ALLOCATOR_NB_BYTES),
-                                           mCurrentOffset(0), mNbFramesTooMuchAllocated(0), mNeedToAllocatedMore(false) {
+                                           mCurrentOffset(0) {
 
     // Allocate a whole block of memory at the beginning
     mMemoryBufferStart = static_cast<char*>(mBaseAllocator.allocate(mTotalSizeBytes));
@@ -48,47 +48,71 @@ SingleFrameAllocator::~SingleFrameAllocator() {
     mBaseAllocator.release(mMemoryBufferStart, mTotalSizeBytes);
 }
 
-
 // Allocate memory of a given size (in bytes) and return a pointer to the
-// allocated memory.
+// allocated memory. Allocated memory must be 16-bytes aligned.
 void* SingleFrameAllocator::allocate(size_t size) {
 
     // Lock the method with a mutex
     std::lock_guard<std::mutex> lock(mMutex);
 
+    // Allocate a little bit more memory to make sure we can return an aligned address
+    const size_t totalSize = size + GLOBAL_ALIGNMENT;
+
     // Check that there is enough remaining memory in the buffer
-    if (mCurrentOffset + size > mTotalSizeBytes) {
+    if (mCurrentOffset + totalSize > mTotalSizeBytes) {
 
-        // We need to allocate more memory next time reset() is called
-        mNeedToAllocatedMore = true;
+        const size_t previousTotalSizeBytes = mTotalSizeBytes;
 
-        // Return default memory allocation
-        return mBaseAllocator.allocate(size);
+        // Multiply the total memory to allocate by two
+        mTotalSizeBytes *= 2;
+
+        // Allocate a whole block of memory
+        void* allocatedMemory = mBaseAllocator.allocate(mTotalSizeBytes);
+        assert(allocatedMemory != nullptr);
+
+        // Check that allocated memory is 16-bytes aligned
+        assert(reinterpret_cast<uintptr_t>(allocatedMemory) % GLOBAL_ALIGNMENT == 0);
+
+        char* newMemoryBufferStart = static_cast<char*>(allocatedMemory);
+
+        // Copy the previous memory bloc to new new location
+        memcpy(newMemoryBufferStart, mMemoryBufferStart, previousTotalSizeBytes);
+
+        // Release the memory allocated at the beginning
+        mBaseAllocator.release(mMemoryBufferStart, previousTotalSizeBytes);
+
+        mMemoryBufferStart = newMemoryBufferStart;
     }
 
     // Next available memory location
     void* nextAvailableMemory = mMemoryBufferStart + mCurrentOffset;
 
+    // Take care of alignment to make sure that we always return an address to the
+    // enforce the global alignment of the library
+    uintptr_t currentAdress = reinterpret_cast<uintptr_t>(nextAvailableMemory);
+
+    // Calculate the adjustment by masking off the lower bits of the address, to determine how "misaligned" it is.
+    size_t mask = GLOBAL_ALIGNMENT - 1;
+    uintptr_t misalignment = currentAdress & mask;
+    ptrdiff_t alignmentOffset = GLOBAL_ALIGNMENT - misalignment;
+
+    // Compute the aligned address
+    uintptr_t alignedAdress = currentAdress + alignmentOffset;
+    nextAvailableMemory = reinterpret_cast<void*>(alignedAdress);
+
     // Increment the offset
-    mCurrentOffset += size;
+    mCurrentOffset += totalSize;
+
+    // Check that allocated memory is 16-bytes aligned
+    assert(reinterpret_cast<uintptr_t>(nextAvailableMemory) % GLOBAL_ALIGNMENT == 0);
 
     // Return the next available memory location
     return nextAvailableMemory;
 }
 
 // Release previously allocated memory.
-void SingleFrameAllocator::release(void* pointer, size_t size) {
+void SingleFrameAllocator::release(void* /*pointer*/, size_t /*size*/) {
 
-    // Lock the method with a mutex
-    std::lock_guard<std::mutex> lock(mMutex);
-
-    // If allocated memory is not within the single frame allocation range
-    char* p = static_cast<char*>(pointer);
-    if (p < mMemoryBufferStart || p > mMemoryBufferStart + mTotalSizeBytes) {
-
-        // Use default deallocation
-        mBaseAllocator.release(pointer, size);
-    }
 }
 
 // Reset the marker of the current allocated memory
@@ -97,48 +121,6 @@ void SingleFrameAllocator::reset() {
     // Lock the method with a mutex
     std::lock_guard<std::mutex> lock(mMutex);
 
-    // If too much memory is allocated
-    if (mCurrentOffset < mTotalSizeBytes / 2) {
-
-        mNbFramesTooMuchAllocated++;
-
-        if (mNbFramesTooMuchAllocated > NB_FRAMES_UNTIL_SHRINK) {
-
-            // Release the memory allocated at the beginning
-            mBaseAllocator.release(mMemoryBufferStart, mTotalSizeBytes);
-
-            // Divide the total memory to allocate by two
-            mTotalSizeBytes /= 2;
-            if (mTotalSizeBytes == 0) mTotalSizeBytes = 1;
-
-            // Allocate a whole block of memory at the beginning
-            mMemoryBufferStart = static_cast<char*>(mBaseAllocator.allocate(mTotalSizeBytes));
-            assert(mMemoryBufferStart != nullptr);
-
-            mNbFramesTooMuchAllocated = 0;
-        }
-    }
-    else {
-        mNbFramesTooMuchAllocated = 0;
-    }
-
-    // If we need to allocate more memory
-    if (mNeedToAllocatedMore) {
-
-        // Release the memory allocated at the beginning
-        mBaseAllocator.release(mMemoryBufferStart, mTotalSizeBytes);
-
-        // Multiply the total memory to allocate by two
-        mTotalSizeBytes *= 2;
-
-        // Allocate a whole block of memory at the beginning
-        mMemoryBufferStart = static_cast<char*>(mBaseAllocator.allocate(mTotalSizeBytes));
-        assert(mMemoryBufferStart != nullptr);
-
-        mNeedToAllocatedMore = false;
-        mNbFramesTooMuchAllocated = 0;
-    }
-
     // Reset the current offset at the beginning of the block
     mCurrentOffset = 0;
 }