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, 8 insertions, 4 deletions

diff --git a/src/gallium/targets/libgl-xlib/SConscript b/src/gallium/targets/libgl-xlib/SConscript
index e1c78dd06a0..1c816ff7762 100644
--- a/src/gallium/targets/libgl-xlib/SConscript
+++ b/src/gallium/targets/libgl-xlib/SConscript
@@ -48,11 +48,15 @@ if env['llvm']:
     env.Prepend(LIBS = [llvmpipe])
 
 if env['platform'] != 'darwin':
+    # 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',
+        ])
     env.Append(SHLINKFLAGS = [
-       # Disallow undefined symbols
-       '-Wl,-z,defs',
-       # Restrict exported symbols
-       '-Wl,--version-script=%s' % File("libgl-xlib.sym").srcnode().path,
+        # Restrict exported symbols
+        '-Wl,--version-script=%s' % File("libgl-xlib.sym").srcnode().path,
     ])
 
 # libGL.so.1.5