[SYCL] Add SYCL_E2E_RUN_LAUNCHER configuration option (#1613)

It allows to inject extra "launcher" prefix into
active *_RUN_PLACEHOLDER substitutions and can be used, for example, to
execute all the tests under valgrind.

However, local experiments with some internal ifrastructure showed that,
while helpful, it's not enough, so two more minor modifications are done
as part of this change:
  - Enable recursive substitutions when SYCL_E2E_RUN_LAUNCHER is enabled
  - Provide %e2e_tests_root substitution. It is expected to be used in
    conjunction with existing "%s" substitution to be able to get a
    unique relative path to the current test.

Author: aelovikov-intel

SYCL/lit.cfg.py

@@ -312,6 +312,9 @@
     if platform.system() == "Linux":
         cpu_run_on_linux_substitute = cpu_run_substitute
         cpu_check_on_linux_substitute = "| FileCheck %s"
+
+    if config.run_launcher:
+        cpu_run_substitute += " {}".format(config.run_launcher)
 else:
     lit_config.warning("CPU device not used")
 
@@ -353,6 +356,8 @@
     if config.sycl_be == "ext_oneapi_cuda":
         gpu_run_substitute += "SYCL_PI_CUDA_ENABLE_IMAGE_SUPPORT=1 "
 
+    if config.run_launcher:
+        gpu_run_substitute += " {}".format(config.run_launcher)
 else:
     lit_config.warning("GPU device not used")
 
@@ -370,11 +375,18 @@
     acc_run_substitute = " env ONEAPI_DEVICE_SELECTOR='*:acc' "
     acc_check_substitute = "| FileCheck %s"
     config.available_features.add('accelerator')
+
+    if config.run_launcher:
+        acc_run_substitute += " {}".format(config.run_launcher)
 else:
     lit_config.warning("Accelerator device not used")
 config.substitutions.append( ('%ACC_RUN_PLACEHOLDER',  acc_run_substitute) )
 config.substitutions.append( ('%ACC_CHECK_PLACEHOLDER',  acc_check_substitute) )
 
+if config.run_launcher:
+    config.substitutions.append(('%e2e_tests_root', config.test_source_root))
+    config.recursiveExpansionLimit = 10
+
 if config.sycl_be == 'ext_oneapi_cuda' or (config.sycl_be == 'ext_oneapi_hip' and config.hip_platform == 'NVIDIA'):
     config.substitutions.append( ('%sycl_triple',  "nvptx64-nvidia-cuda" ) )
 elif config.sycl_be == 'ext_oneapi_hip' and config.hip_platform == 'AMD':

SYCL/lit.site.cfg.py.in

@@ -34,6 +34,8 @@ config.external_tests = "@SYCL_EXTERNAL_TESTS@"
 config.extra_include = "@CMAKE_CURRENT_SOURCE_DIR@/include"
 config.gpu_aot_target_opts = lit_config.params.get("gpu_aot_target_opts", "@GPU_AOT_TARGET_OPTS@")
 
+config.run_launcher = "@SYCL_E2E_RUN_LAUNCHER@"
+
 import lit.llvm
 lit.llvm.initialize(lit_config, config)