Fix ASAN execution for the MLIR Python tests

First the leak sanitizer has to be disabled, as even an empty script
leads to leak detection with Python.
Then we need to preload the ASAN runtime, as the main binary (python)
won't be linked against it. This will only work on Linux right now.

Differential Revision: https://reviews.llvm.org/D111004

mlir/test/lit.cfg.py

@@ -68,7 +68,6 @@
 
 # The following tools are optional
 tools.extend([
-    ToolSubst('%PYTHON', config.python_executable, unresolved='ignore'),
     ToolSubst('toy-ch1', unresolved='ignore'),
     ToolSubst('toy-ch2', unresolved='ignore'),
     ToolSubst('toy-ch3', unresolved='ignore'),
@@ -80,6 +79,16 @@
     ToolSubst('%vulkan_wrapper_library_dir', config.vulkan_wrapper_library_dir, unresolved='ignore'),
     ToolSubst('%mlir_integration_test_dir', config.mlir_integration_test_dir, unresolved='ignore'),
 ])
+
+python_executable = config.python_executable
+# Python configuration with sanitizer requires some magic preloading. This will only work on clang/linux.
+# TODO: detect Darwin/Windows situation (or mark these tests as unsupported on these platforms).
+if "asan" in config.available_features and "Linux" in config.host_os:
+  python_executable = f"LD_PRELOAD=$({config.host_cxx} -print-file-name=libclang_rt.asan-{config.host_arch}.so) {config.python_executable}"
+tools.extend([
+  ToolSubst('%PYTHON', python_executable, unresolved='ignore'),
+])
+
 llvm_config.add_tool_substitutions(tools, tool_dirs)
 
 

mlir/test/python/lit.local.cfg

@@ -1,8 +1,4 @@
-# Disable with sanitizers for now, this require some more setup apparently.
-for san in ['asan', 'msan', 'ubsan']:
-   if (san in config.available_features):
-      config.unsupported = True
-
+config.environment['ASAN_OPTIONS'] = 'detect_leaks=0'
 if not config.enable_bindings_python:
   config.unsupported = True
 config.excludes.add('python_test_ops.td')