From abf230a9ac4750f4cacfb1d4c8610732c15b417c Mon Sep 17 00:00:00 2001
From: Michael Lotz <mmlr@mlotz.ch>
Date: Wed, 8 Apr 2015 12:26:30 +0200
Subject: [PATCH] malloc_debug: Set default alignment to max_align_t if
 available.

For it to be available we build malloc_debug in C++11 mode when not
using GCC2. Note that max_align_t is not in the std namespace in GCC4
versions prior to GCC 4.9. The extra "using namespace std" is there to
be forward compatible once we update.
---
 src/system/libroot/posix/malloc_debug/Jamfile         |  4 ++++
 .../libroot/posix/malloc_debug/guarded_heap.cpp       |  9 ++++++++-
 src/system/libroot/posix/malloc_debug/heap.cpp        | 11 +++++++++--
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/src/system/libroot/posix/malloc_debug/Jamfile b/src/system/libroot/posix/malloc_debug/Jamfile
index ce2d68a298..903167d934 100644
--- a/src/system/libroot/posix/malloc_debug/Jamfile
+++ b/src/system/libroot/posix/malloc_debug/Jamfile
@@ -7,6 +7,10 @@ for architectureObject in [ MultiArchSubDirSetup ] {
 	on $(architectureObject) {
 		local architecture = $(TARGET_PACKAGING_ARCH) ;
 
+		if $(architecture) != x86_gcc2 {
+			SubDirC++Flags -std=gnu++11 ;
+		}
+
 		UsePrivateSystemHeaders ;
 
 		MergeObject <$(architecture)>posix_malloc_debug.o :
diff --git a/src/system/libroot/posix/malloc_debug/guarded_heap.cpp b/src/system/libroot/posix/malloc_debug/guarded_heap.cpp
index 1e0bd70d48..5084e2c7bc 100644
--- a/src/system/libroot/posix/malloc_debug/guarded_heap.cpp
+++ b/src/system/libroot/posix/malloc_debug/guarded_heap.cpp
@@ -19,7 +19,14 @@
 
 
 static bool sDebuggerCalls = true;
+
+#if __cplusplus >= 201103L
+#include <cstddef>
+using namespace std;
+static size_t sDefaultAlignment = alignof(max_align_t);
+#else
 static size_t sDefaultAlignment = 0;
+#endif
 
 
 static void
@@ -950,7 +957,7 @@ __init_heap_post_env(void)
 		const char *argument = strchr(mode, 'a');
 		if (argument != NULL
 			&& sscanf(argument, "a%" B_SCNuSIZE, &defaultAlignment) == 1
-			&& defaultAlignment > 0) {
+			&& defaultAlignment >= 0) {
 			heap_debug_set_default_alignment(defaultAlignment);
 		}
 	}
diff --git a/src/system/libroot/posix/malloc_debug/heap.cpp b/src/system/libroot/posix/malloc_debug/heap.cpp
index 1b735b59ac..533a42b268 100644
--- a/src/system/libroot/posix/malloc_debug/heap.cpp
+++ b/src/system/libroot/posix/malloc_debug/heap.cpp
@@ -44,7 +44,14 @@ static bool sParanoidValidation = false;
 static thread_id sWallCheckThread = -1;
 static bool sStopWallChecking = false;
 static bool sUseGuardPage = false;
-static bool sDefaultAlignment = 0;
+
+#if __cplusplus >= 201103L
+#include <cstddef>
+using namespace std;
+static size_t sDefaultAlignment = alignof(max_align_t);
+#else
+static size_t sDefaultAlignment = 0;
+#endif
 
 
 void
@@ -1852,7 +1859,7 @@ __init_heap_post_env(void)
 		const char *argument = strchr(mode, 'a');
 		if (argument != NULL
 			&& sscanf(argument, "a%" B_SCNuSIZE, &defaultAlignment) == 1
-			&& defaultAlignment > 0) {
+			&& defaultAlignment >= 0) {
 			heap_debug_set_default_alignment(defaultAlignment);
 		}
 	}