1 files changed, 161 insertions, 0 deletions
diff --git a/gnu/llvm/libcxx/src/experimental/memory_resource.cpp b/gnu/llvm/libcxx/src/experimental/memory_resource.cpp
new file mode 100644
index 00000000000..68c5bc99cc7
--- /dev/null
+++ b/gnu/llvm/libcxx/src/experimental/memory_resource.cpp
@@ -0,0 +1,161 @@
+//===------------------------ memory_resource.cpp -------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "experimental/memory_resource"
+
+#ifndef _LIBCPP_HAS_NO_ATOMIC_HEADER
+#include "atomic"
+#elif !defined(_LIBCPP_HAS_NO_THREADS)
+#include "mutex"
+#if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
+#pragma comment(lib, "pthread")
+#endif
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+
+// memory_resource
+
+//memory_resource::~memory_resource() {}
+
+// new_delete_resource()
+
+class _LIBCPP_TYPE_VIS __new_delete_memory_resource_imp
+    : public memory_resource
+{
+    void *do_allocate(size_t size, size_t align) override {
+#ifdef _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
+        if (__is_overaligned_for_new(align))
+            __throw_bad_alloc();
+#endif
+        return _VSTD::__libcpp_allocate(size, align);
+    }
+
+    void do_deallocate(void *p, size_t n, size_t align) override {
+      _VSTD::__libcpp_deallocate(p, n, align);
+    }
+
+    bool do_is_equal(memory_resource const & other) const _NOEXCEPT override
+        { return &other == this; }
+
+public:
+    ~__new_delete_memory_resource_imp() override = default;
+};
+
+// null_memory_resource()
+
+class _LIBCPP_TYPE_VIS __null_memory_resource_imp
+    : public memory_resource
+{
+public:
+    ~__null_memory_resource_imp() = default;
+
+protected:
+    virtual void* do_allocate(size_t, size_t) {
+        __throw_bad_alloc();
+    }
+    virtual void do_deallocate(void *, size_t, size_t) {}
+    virtual bool do_is_equal(memory_resource const & __other) const _NOEXCEPT
+    { return &__other == this; }
+};
+
+namespace {
+
+union ResourceInitHelper {
+  struct {
+    __new_delete_memory_resource_imp new_delete_res;
+    __null_memory_resource_imp       null_res;
+  } resources;
+  char dummy;
+  _LIBCPP_CONSTEXPR_AFTER_CXX11 ResourceInitHelper() : resources() {}
+  ~ResourceInitHelper() {}
+};
+
+// Detect if the init_priority attribute is supported.
+#if (defined(_LIBCPP_COMPILER_GCC) && defined(__APPLE__)) \
+  || defined(_LIBCPP_COMPILER_MSVC)
+// GCC on Apple doesn't support the init priority attribute,
+// and MSVC doesn't support any GCC attributes.
+# define _LIBCPP_INIT_PRIORITY_MAX
+#else
+# define _LIBCPP_INIT_PRIORITY_MAX __attribute__((init_priority(101)))
+#endif
+
+// When compiled in C++14 this initialization should be a constant expression.
+// Only in C++11 is "init_priority" needed to ensure initialization order.
+#if _LIBCPP_STD_VER > 11
+_LIBCPP_SAFE_STATIC
+#endif
+ResourceInitHelper res_init _LIBCPP_INIT_PRIORITY_MAX;
+
+} // end namespace
+
+
+memory_resource * new_delete_resource() _NOEXCEPT {
+    return &res_init.resources.new_delete_res;
+}
+
+memory_resource * null_memory_resource() _NOEXCEPT {
+    return &res_init.resources.null_res;
+}
+
+// default_memory_resource()
+
+static memory_resource *
+__default_memory_resource(bool set = false, memory_resource * new_res = nullptr) _NOEXCEPT
+{
+#ifndef _LIBCPP_HAS_NO_ATOMIC_HEADER
+    _LIBCPP_SAFE_STATIC static atomic<memory_resource*> __res =
+        ATOMIC_VAR_INIT(&res_init.resources.new_delete_res);
+    if (set) {
+        new_res = new_res ? new_res : new_delete_resource();
+        // TODO: Can a weaker ordering be used?
+        return _VSTD::atomic_exchange_explicit(
+            &__res, new_res, memory_order_acq_rel);
+    }
+    else {
+        return _VSTD::atomic_load_explicit(
+            &__res, memory_order_acquire);
+    }
+#elif !defined(_LIBCPP_HAS_NO_THREADS)
+    _LIBCPP_SAFE_STATIC static memory_resource * res = &res_init.resources.new_delete_res;
+    static mutex res_lock;
+    if (set) {
+        new_res = new_res ? new_res : new_delete_resource();
+        lock_guard<mutex> guard(res_lock);
+        memory_resource * old_res = res;
+        res = new_res;
+        return old_res;
+    } else {
+        lock_guard<mutex> guard(res_lock);
+        return res;
+    }
+#else
+    _LIBCPP_SAFE_STATIC static memory_resource* res = &res_init.resources.new_delete_res;
+    if (set) {
+        new_res = new_res ? new_res : new_delete_resource();
+        memory_resource * old_res = res;
+        res = new_res;
+        return old_res;
+    } else {
+        return res;
+    }
+#endif
+}
+
+memory_resource * get_default_resource() _NOEXCEPT
+{
+    return __default_memory_resource();
+}
+
+memory_resource * set_default_resource(memory_resource * __new_res) _NOEXCEPT
+{
+    return __default_memory_resource(true, __new_res);
+}
+
+_LIBCPP_END_NAMESPACE_LFTS_PMR