Modify allocator_shim to support _aligned_alloc(), _aligned_free().

base/allocator/allocator_shim.cc

Index: base/allocator/allocator_shim.cc
diff --git a/base/allocator/allocator_shim.cc b/base/allocator/allocator_shim.cc
index fd6d741c04d3e195c00305477fbf9a26553e38dc..9d3d932d59f2e80787a62c4c2af1565bfe43a2f4 100644
--- a/base/allocator/allocator_shim.cc
+++ b/base/allocator/allocator_shim.cc
@@ -65,6 +65,7 @@ void* je_realloc(void* p, size_t s);
 void je_free(void* s);
 size_t je_msize(void* p);
 bool je_malloc_init_hard();
+void* je_memalign(size_t a, size_t s);
 }
 
 extern "C" {
@@ -299,6 +300,66 @@ extern "C" void _heap_term() {}
 // the rest of the CRT is still usable.
 extern "C" void* _crtheap = reinterpret_cast<void*>(1);
 
+// Provide support for aligned memory through Windows only _aligned_malloc().
+void* _aligned_malloc(size_t size, size_t alignment) {
+  // _aligned_malloc guarantees parameter validation, so do so here.  These
+  // checks are somewhat stricter than _aligned_malloc() since we're effectively
+  // using memalign() under the hood.
+  DCHECK_GT(size, 0U);
+  DCHECK_EQ(alignment & (alignment - 1), 0U);
+  DCHECK_EQ(alignment % sizeof(void*), 0U);
+
+  void* ptr;
+  for (;;) {
+#ifdef ENABLE_DYNAMIC_ALLOCATOR_SWITCHING
+    switch (allocator) {
+      case JEMALLOC:
+        ptr = je_memalign(alignment, size);
+        break;
+      case WINHEAP:
+      case WINLFH:
+        ptr = win_heap_memalign(alignment, size);
+        break;
+      case TCMALLOC:
+      default:
+        ptr = tc_memalign(alignment, size);
+        break;
+    }
+#else
+    // TCMalloc case.
+    ptr = tc_memalign(alignment, size);
+#endif
+    if (ptr) {
+      // Sanity check alignment.
+      DCHECK_EQ(reinterpret_cast<uintptr_t>(ptr) & (alignment - 1), 0U);
+      return ptr;
+    }
+
+    if (!new_mode || !call_new_handler(true))
+      break;
+  }
+  return ptr;
+}
+
+void _aligned_free(void* p) {
+  // Both JEMalloc and TCMalloc return pointers from memalign() that are safe to
+  // use with free().  Pointers allocated with win_heap_memalign() MUST be freed
+  // via win_heap_memalign_free() since the aligned pointer is not the real one.
+#ifdef ENABLE_DYNAMIC_ALLOCATOR_SWITCHING
+  switch (allocator) {
+    case JEMALLOC:
+      je_free(p);
+      return;
+    case WINHEAP:
+    case WINLFH:
+      win_heap_memalign_free(p);
+      return;
+  }
+#endif
+  // TCMalloc case.
+  do_free(p);
+}
+
 #endif  // WIN32
 
 #include "generic_allocators.cc"