prepare_binding_Python: print readable errors if SWIG fails

When swig fails, all the errors are squished onto one line with \n
quoting. It's very hard to read. This will print them out in a more
reasonable format.

Patch by: Lawrence D'Anna

Differential revision: https://reviews.llvm.org/D67790

llvm-svn: 372442

1 files changed, 6 insertions, 4 deletions

diff --git a/lldb/scripts/Python/prepare_binding_Python.py b/lldb/scripts/Python/prepare_binding_Python.py
index 7d13d6ebb17..fc409b09eb3 100644
--- a/lldb/scripts/Python/prepare_binding_Python.py
+++ b/lldb/scripts/Python/prepare_binding_Python.py
@@ -231,11 +231,13 @@ def do_swig_rebuild(options, dependency_file, config_build_dir, settings):
     swig_stdout, swig_stderr = process.communicate()
     return_code = process.returncode
     if return_code != 0:
+        swig_stdout = swig_stdout.decode('utf8', errors='replace').rstrip()
+        swig_stderr = swig_stderr.decode('utf8', errors='replace').rstrip()
+        swig_stdout = re.sub(r'^(?=.)', 'stdout: ', swig_stdout, flags=re.MULTILINE)
+        swig_stderr = re.sub(r'^(?=.)', 'stderr: ', swig_stderr, flags=re.MULTILINE)
         logging.error(
-            "swig failed with error code %d: stdout=%s, stderr=%s",
-            return_code,
-            swig_stdout,
-            swig_stderr)
+            "swig failed with error code %d\n%s%s",
+            return_code, swig_stdout, swig_stderr)
         logging.error(
             "command line:\n%s", ' '.join(command))
         sys.exit(return_code)