scons: Add Undefined Behavior Sanitizer (UBSan) option

This patch adds the Undefined Behavior Sanitizer (UBSan) for clang and
gcc >= 4.9. Due to the performance impact, the usage is guarded by a
command-line option.

1 files changed, 11 insertions, 0 deletions

diff --git a/SConstruct b/SConstruct
index 1d1b95711..1078a3e96 100755
--- a/SConstruct
+++ b/SConstruct
@@ -189,6 +189,8 @@ AddLocalOption('--without-python', dest='without_python',
 AddLocalOption('--without-tcmalloc', dest='without_tcmalloc',
                action='store_true',
                help='Disable linking against tcmalloc')
+AddLocalOption('--with-ubsan', dest='with_ubsan', action='store_true',
+               help='Build with Undefined Behavior Sanitizer if available')
 
 termcap = get_termcap(GetOption('use_colors'))
 
@@ -602,6 +604,15 @@ if main['GCC']:
                 'binutils to 2.23.' + \
                 termcap.Normal
 
+    # Make sure we warn if the user has requested to compile with the
+    # Undefined Benahvior Sanitizer and this version of gcc does not
+    # support it.
+    if GetOption('with_ubsan') and \
+            compareVersions(gcc_version, '4.9') < 0:
+        print termcap.Yellow + termcap.Bold + \
+            'Warning: UBSan is only supported using gcc 4.9 and later.' + \
+            termcap.Normal
+
     # Add the appropriate Link-Time Optimization (LTO) flags
     # unless LTO is explicitly turned off. Note that these flags
     # are only used by the fast target.