1 files changed, 82 insertions, 0 deletions
diff --git a/memory/mozalloc/cxxalloc.h b/memory/mozalloc/cxxalloc.h
new file mode 100644
index 0000000000..c6fb4bb1dc
--- /dev/null
+++ b/memory/mozalloc/cxxalloc.h
@@ -0,0 +1,82 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_cxxalloc_h
+#define mozilla_cxxalloc_h
+
+/*
+ * We implement the default operators new/delete as part of
+ * libmozalloc, replacing their definitions in libstdc++.  The
+ * operator new* definitions in libmozalloc will never return a NULL
+ * pointer.
+ *
+ * Each operator new immediately below returns a pointer to memory
+ * that can be delete'd by any of
+ *
+ *   (1) the matching infallible operator delete immediately below
+ *   (2) the matching system |operator delete(void*, std::nothrow)|
+ *   (3) the matching system |operator delete(void*) noexcept(false)|
+ *
+ * NB: these are declared |noexcept(false)|, though they will never
+ * throw that exception.  This declaration is consistent with the rule
+ * that |::operator new() noexcept(false)| will never return NULL.
+ *
+ * NB: mozilla::fallible can be used instead of std::nothrow.
+ */
+
+#ifndef MOZALLOC_EXPORT_NEW
+#  define MOZALLOC_EXPORT_NEW MFBT_API
+#endif
+
+MOZALLOC_EXPORT_NEW void* operator new(size_t size) noexcept(false) {
+  return moz_xmalloc(size);
+}
+
+MOZALLOC_EXPORT_NEW void* operator new(size_t size,
+                                       const std::nothrow_t&) noexcept(true) {
+  return malloc_impl(size);
+}
+
+MOZALLOC_EXPORT_NEW void* operator new[](size_t size) noexcept(false) {
+  return moz_xmalloc(size);
+}
+
+MOZALLOC_EXPORT_NEW void* operator new[](size_t size,
+                                         const std::nothrow_t&) noexcept(true) {
+  return malloc_impl(size);
+}
+
+MOZALLOC_EXPORT_NEW void operator delete(void* ptr) noexcept(true) {
+  return free_impl(ptr);
+}
+
+MOZALLOC_EXPORT_NEW void operator delete(void* ptr,
+                                         const std::nothrow_t&) noexcept(true) {
+  return free_impl(ptr);
+}
+
+MOZALLOC_EXPORT_NEW void operator delete[](void* ptr) noexcept(true) {
+  return free_impl(ptr);
+}
+
+MOZALLOC_EXPORT_NEW void operator delete[](
+    void* ptr, const std::nothrow_t&) noexcept(true) {
+  return free_impl(ptr);
+}
+
+#if defined(XP_WIN)
+// We provide the global sized delete overloads unconditionally because the
+// MSVC runtime headers do, despite compiling with /Zc:sizedDealloc-
+MOZALLOC_EXPORT_NEW void operator delete(void* ptr,
+                                         size_t /*size*/) noexcept(true) {
+  return free_impl(ptr);
+}
+
+MOZALLOC_EXPORT_NEW void operator delete[](void* ptr,
+                                           size_t /*size*/) noexcept(true) {
+  return free_impl(ptr);
+}
+#endif
+
+#endif /* mozilla_cxxalloc_h */