[gcc r13-3627] Add gcc/make-unique.h

[gcc r13-3627] Add gcc/make-unique.h

[David Malcolm]

https://gcc.gnu.org/g:00d7c8ff16e6838273cea808ffbe22e98104f9d5

commit r13-3627-g00d7c8ff16e6838273cea808ffbe22e98104f9d5
Author: David Malcolm <dmalcolm@redhat.com>
Date:   Thu Nov 3 10:22:47 2022 -0400

    Add gcc/make-unique.h
    
    This patch adds gcc/make-unique.h, containing a minimal C++11
    implementation of make_unique (std::make_unique is C++14).
    
    gcc/ChangeLog:
            * make-unique.h: New file.
    
    Signed-off-by: David Malcolm <dmalcolm@redhat.com>

Diff:
---
 gcc/make-unique.h | 44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/gcc/make-unique.h b/gcc/make-unique.h
new file mode 100644
index 00000000000..c9a7d6ef6ce
--- /dev/null
+++ b/gcc/make-unique.h
@@ -0,0 +1,44 @@
+/* Minimal implementation of make_unique for C++11 compatibility.
+   Copyright (C) 2022 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#ifndef GCC_MAKE_UNIQUE
+#define GCC_MAKE_UNIQUE
+
+/* This header uses std::unique_ptr, but <memory> can't be directly
+   included due to issues with macros.  Hence <memory> must be included
+   from system.h by defining INCLUDE_MEMORY in any source file using
+   make-unique.h.  */
+
+#ifndef INCLUDE_MEMORY
+# error "You must define INCLUDE_MEMORY before including system.h to use make-unique.h"
+#endif
+
+#include <type_traits>
+
+/* Minimal implementation of make_unique for C++11 compatibility
+   (std::make_unique is C++14).  */
+
+template<typename T, typename... Args>
+inline typename std::enable_if<!std::is_array<T>::value, std::unique_ptr<T>>::type
+make_unique(Args&&... args)
+{
+  return std::unique_ptr<T> (new T (std::forward<Args> (args)...));
+}
+
+#endif /* ! GCC_MAKE_UNIQUE */