From 69860628a7d543ec8cafa6bee65ad44801597e30 Mon Sep 17 00:00:00 2001
From: Andrzej Kotulski <akotulski@fb.com>
Date: Fri, 1 Apr 2016 02:26:02 -0700
Subject: [PATCH] Better detection of stdlibc++/libc++ and C++11

Summary:public
1. Make detection of libc++/stdlibc++ headers more robust
2. Turn on c++11 only for newer versions of stdlibc++

Reviewed By: jvillard

Differential Revision: D3121187

fb-gh-sync-id: c2e5be5
fbshipit-source-id: c2e5be5
---
 .../cpp/include/infer_model/portability.h     | 25 ++++++++++++++++---
 infer/models/cpp/include/memory               |  6 +++--
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/infer/models/cpp/include/infer_model/portability.h b/infer/models/cpp/include/infer_model/portability.h
index aa3695fb0..6af8a4cd9 100644
--- a/infer/models/cpp/include/infer_model/portability.h
+++ b/infer/models/cpp/include/infer_model/portability.h
@@ -8,12 +8,29 @@
  */
 
 #pragma once
-// TODO set it in configure script instead
-// This is hacky attempt to follow what folly does
+// This is a hacky attempt to follow what folly does
 // https://github.com/facebook/folly/blob/b1eb6819f3ffe6b645f39d505ca8ace3116b7873/folly/configure.ac#L232
-#if !defined(INFER_USE_LIBCPP) && defined(__APPLE__)
+// Depending whether the project is compiled with libc++ or stdlibc++, include their
+// internal config headers to get information about versions
+#if __has_include(<__config>) // defines _LIBCPP_VERSION
+#include <__config>
+#elif __has_include(<bits / c++ config.h>) // defines __GLIBCXX__
+#include <bits/c++config.h>
+#endif
+
+// Figure out whether the library really supports c++11 standard
+#if __cplusplus >= 201103L
+#if __GLIBCXX__ >= 20130531
+// C++11 is really supported from gcc 4.8.1 onward.
+#define INFER_CPP11_ON 1
+#elif defined _LIBCPP_VERSION // for now assume libc++ always supported c++11
+#define INFER_CPP11_ON 1
+#endif
+#endif // __cplusplus >= 201103L
+
+#if !defined(INFER_USE_LIBCPP) && defined(_LIBCPP_VERSION)
 #define INFER_USE_LIBCPP 1
-#elif defined(FOLLY_USE_LIBCPP)
+#elif defined(FOLLY_USE_LIBCPP) // follow folly configuration if it's available
 #define INFER_USE_LIBCPP 1
 #endif
 
diff --git a/infer/models/cpp/include/memory b/infer/models/cpp/include/memory
index 9182434a0..928659fa5 100644
--- a/infer/models/cpp/include/memory
+++ b/infer/models/cpp/include/memory
@@ -1,5 +1,7 @@
 
-#if __cplusplus >= 201103L
+#include <infer_model/portability.h>
+
+#ifdef INFER_CPP11_ON
 
 #include <infer_model/begin_name_override.inc>
 #include_next <memory>
@@ -8,7 +10,7 @@
 #include<infer_model/unique_ptr.h>
 #include<infer_model/shared_ptr.h>
 
-#else // __cplusplus < 201103L
+#else 
 // don't model memory for pre-C++11 code
 #include_next <memory>
 #endif