scons: Allow building with Address Sanitizer.

libasan is never linked to shared objects (which doesn't go well with
-z,defs).  It must either be linked to the main executable, or (more
practically for OpenGL drivers) be pre-loaded via LD_PRELOAD.

Otherwise works.

I didn't find anything with llvmpipe.  I suspect the fact that the
JIT compiled code isn't instrumented means there are lots of errors it
can't catch.

But for non-JIT drivers, the Address/Leak Sanitizers seem like a faster
alternative to Valgrind.

Usage (Ubuntu 15.10):

   scons asan=1 libgl-xlib
   export LD_LIBRARY_PATH=$PWD/build/linux-x86_64-debug/gallium/targets/libgl-xlib
   LD_PRELOAD=libasan.so.2 any-opengl-application

Acked-by: Roland Scheidegger <[email protected]>

1 files changed, 6 insertions, 2 deletions

diff --git a/src/mesa/drivers/x11/SConscript b/src/mesa/drivers/x11/SConscript
index 45419973d39..59c8df4b3c2 100644
--- a/src/mesa/drivers/x11/SConscript
+++ b/src/mesa/drivers/x11/SConscript
@@ -34,9 +34,13 @@ sources = [
 	'xm_tri.c',
 ]
 
-# Disallow undefined symbols
 if env['platform'] != 'darwin':
-    env.Append(SHLINKFLAGS = ['-Wl,-z,defs'])
+    # Disallow undefined symbols, except with Address Sanitizer, since libasan
+    # is not linked on shared libs, as it should be LD_PRELOAD'ed instead
+    if not env['asan']:
+        env.Append(SHLINKFLAGS = [
+            '-Wl,-z,defs',
+        ])
 
 # libGL.so.1.6
 libgl_1_6 = env.SharedLibrary(