Share default CPU allocator with Mlas preferred alignment (#1682)

Description: make default CPU allocator to use MLAS preferred alignment

Motivation and Context

This is needed for C API to have an aligned default CPU allocator, the same as the one in CPU provider

onnxruntime/core/framework/allocator.cc

@@ -3,35 +3,18 @@
 
 #include "core/framework/allocator.h"
 #include "core/framework/allocatormgr.h"
-#include "core/mlas/inc/mlas.h"
+#include "core/framework/utils.h"
 #include <cstdlib>
 #include <sstream>
 
 namespace onnxruntime {
 
 void* CPUAllocator::Alloc(size_t size) {
-  if (size <= 0) return nullptr;
-  void* p;
-  size_t alignment = MlasGetPreferredBufferAlignment();
-#if _MSC_VER
-  p = _aligned_malloc(size, alignment);
-  if (p == nullptr) throw std::bad_alloc();
-#elif defined(_LIBCPP_SGX_CONFIG)
-  p = memalign(alignment, size);
-  if (p == nullptr) throw std::bad_alloc();
-#else
-  int ret = posix_memalign(&p, alignment, size);
-  if (ret != 0) throw std::bad_alloc();
-#endif
-  return p;
+  return utils::DefaultAlloc(size);
 }
 
 void CPUAllocator::Free(void* p) {
-#if _MSC_VER
-  _aligned_free(p);
-#else
-  free(p);
-#endif
+  utils::DefaultFree(p);
 }
 
 const OrtAllocatorInfo& CPUAllocator::Info() const { return *allocator_info_; }

onnxruntime/core/framework/utils.cc

@@ -16,9 +16,35 @@
 #include "core/framework/parallel_executor.h"
 #include "core/framework/session_state.h"
 #include "core/framework/sequential_executor.h"
+#include "core/mlas/inc/mlas.h"
 
 namespace onnxruntime {
 namespace utils {
+void* DefaultAlloc(size_t size) {
+  if (size <= 0) return nullptr;
+  void* p;
+  size_t alignment = MlasGetPreferredBufferAlignment();
+#if _MSC_VER
+  p = _aligned_malloc(size, alignment);
+  if (p == nullptr) throw std::bad_alloc();
+#elif defined(_LIBCPP_SGX_CONFIG)
+  p = memalign(alignment, size);
+  if (p == nullptr) throw std::bad_alloc();
+#else
+  int ret = posix_memalign(&p, alignment, size);
+  if (ret != 0) throw std::bad_alloc();
+#endif
+  return p;
+}
+
+void DefaultFree(void* p) {
+#if _MSC_VER
+  _aligned_free(p);
+#else
+  free(p);
+#endif
+}
+
 AllocatorPtr GetAllocator(const SessionState& session_state, const OrtAllocatorInfo& allocator_info) {
   return session_state.GetExecutionProviders().GetAllocator(allocator_info);
 }

onnxruntime/core/framework/utils.h

@@ -25,6 +25,8 @@ class Logger;
 }
 
 namespace utils {
+void* DefaultAlloc(size_t size);
+void DefaultFree(void* p);
 
 AllocatorPtr GetAllocator(const SessionState& session_state, const OrtAllocatorInfo& allocator_info);
 

onnxruntime/core/session/default_cpu_allocator_c_api.cc

@@ -2,6 +2,7 @@
 // Licensed under the MIT License.
 
 #include <atomic>
+#include "core/framework/utils.h"
 #include "core/session/onnxruntime_cxx_api.h"
 #include <assert.h>
 
@@ -23,10 +24,10 @@ struct OrtDefaultAllocator : OrtAllocatorImpl {
   ~OrtDefaultAllocator() override { OrtReleaseAllocatorInfo(cpuAllocatorInfo); }
 
   void* Alloc(size_t size) {
-    return ::malloc(size);
+    return onnxruntime::utils::DefaultAlloc(size);
   }
   void Free(void* p) {
-    return ::free(p);
+    onnxruntime::utils::DefaultFree(p);
   }
   const OrtAllocatorInfo* Info() const {
     return cpuAllocatorInfo;