- Adjust libclang-python-tests.yml.

- Handle `LLVM_USE_SANITIZER` in `lit.local.cfg`.
- Fix SPARC handling, restrict to Linux/sparc*.
- Explain failure modes, log unhandled ones.

Author: rorth

.github/workflows/libclang-python-tests.yml

@@ -10,15 +10,15 @@ on:
       - 'main'
     paths:
       - 'clang/bindings/python/**'
+      - 'clang/test/bindings/python/**'
       - 'clang/tools/libclang/**'
-      - 'clang/CMakeList.txt'
       - '.github/workflows/libclang-python-tests.yml'
       - '.github/workflows/llvm-project-tests.yml'
   pull_request:
     paths:
       - 'clang/bindings/python/**'
+      - 'clang/test/bindings/python/**'
       - 'clang/tools/libclang/**'
-      - 'clang/CMakeList.txt'
       - '.github/workflows/libclang-python-tests.yml'
       - '.github/workflows/llvm-project-tests.yml'
 
@@ -33,7 +33,9 @@ jobs:
         python-version: ["3.8", "3.13"]
     uses: ./.github/workflows/llvm-project-tests.yml
     with:
-      build_target: check-clang-python
+      build_target: libclang
+      run: |
+        llvm-lit -v tools/clang/test --filter=bindings.sh
       projects: clang
       # There is an issue running on "windows-2019".
       # See https://github.com/llvm/llvm-project/issues/76601#issuecomment-1873049082.

clang/test/bindings/python/bindings.sh

@@ -2,33 +2,20 @@
 
 # UNSUPPORTED: !libclang-loadable
 
-# Tests require libclang.so which is only built with LLVM_ENABLE_PIC=ON
-#
-# Covered by libclang-loadable, may need to augment test for lack of
-# libclang.so.
-
-# Do not try to run if libclang was built with sanitizers because
-# the sanitizer library will likely be loaded too late to perform
-# interception and will then fail.
-# We could use LD_PRELOAD/DYLD_INSERT_LIBRARIES but this isn't
-# portable so its easier just to not run the tests when building
-# with ASan.
-#
-# FIXME: Handle !LLVM_USE_SANITIZER = "".
-# lit.site.cfg.py has config.llvm_use_sanitizer = ""
-
 # Tests fail on Windows, and need someone knowledgeable to fix.
 # It's not clear whether it's a test or a valid binding problem.
 # XFAIL: target={{.*windows.*}}
 
 # The Python FFI interface is broken on AIX: https://bugs.python.org/issue38628.
 # XFAIL: target={{.*-aix.*}}
 
-# AArch64, Hexagon, and Sparc have known test failures that need to be
-# addressed.
+# AArch64 and Hexagon have known test failures that need to be addressed.
 # SystemZ has broken Python/FFI interface:
 # https://reviews.llvm.org/D52840#1265716
-# XFAIL: target={{(aarch64|hexagon|sparc*|s390x)-.*}}
+# XFAIL: target={{(aarch64|hexagon|s390x)-.*}}
+# python SEGVs on Linux/sparc64 when loading libclang.so.  Seems to be an FFI
+# issue, too.
+# XFAIL: target={{sparc.*-.*-linux.*}}
 
 # Tests will fail if cross-compiling for a different target, as tests will try
 # to use the host Python3_EXECUTABLE and make FFI calls to functions in target

clang/test/bindings/python/lit.local.cfg

@@ -1,4 +1,12 @@
 def is_libclang_loadable():
+    # Do not try to run if libclang was built with sanitizers because
+    # the sanitizer library will likely be loaded too late to perform
+    # interception and will then fail.
+    # We could use LD_PRELOAD/DYLD_INSERT_LIBRARIES but this isn't
+    # portable so its easier just to not run the tests when building
+    # with ASan.
+    if config.llvm_use_sanitizer != "":
+        return False
     try:
         sys.path.append(os.path.join(config.clang_src_dir, "bindings/python"))
         from clang.cindex import Config
@@ -7,13 +15,22 @@ def is_libclang_loadable():
         conf.lib
         return True
     except Exception as e:
-        # Benign error modes.
+        # Expected failure modes are considered benign when nothing can be
+        # done about them.
+        #
+        # Cannot load a 32-bit libclang.so into a 64-bit python.
         if "wrong ELF class: ELFCLASS32" in str(e):
             return False
+        # If libclang.so is missing, it must have been disabled intentionally,
+        # e.g. by building with LLVM_ENABLE_PIC=OFF.
         elif "No such file or directory" in str(e):
             return False
-        # Unknown error modes.
+        # Unexpected failure modes need to be investigated to either fix an
+        # underlying bug or accept the failure, so return True.  This causes
+        # tests to run and FAIL, drawing developer attention.
         else:
+            print("warning: unhandled failure in is_libclang_loadable: "
+                  + str(e), file=sys.stderr)
             return True
 
 if is_libclang_loadable():