Added --find-swig option to allow searching for swig in path or other likely locations.

llvm-svn: 253346

lldb/scripts/prepare_bindings.py

@@ -13,6 +13,7 @@ to see a description of the supported command line arguments.
 import argparse
 import logging
 import os
+import platform
 import sys
 
 
@@ -116,6 +117,13 @@ def process_args(args):
         help=(
             "Configuration build dir, will use python module path "
             "if unspecified."))
+    parser.add_argument(
+        "--find-swig",
+        action="store_true",
+        help=(
+            "Indicates the swig executable should be searched for "
+            "if not eplicitly provided.  Either this or the explicit "
+            "swig executable option must be provided."))
     parser.add_argument(
         "--framework",
         action="store_true",
@@ -170,6 +178,63 @@ def process_args(args):
     return options
 
 
+def find_file_in_paths(paths, exe_basename):
+    """Returns the full exe path for the first path match.
+
+    @params paths the list of directories to search for the exe_basename
+    executable
+    @params exe_basename the name of the file for which to search.
+    e.g. "swig" or "swig.exe".
+
+    @return the full path to the executable if found in one of the
+    given paths; otherwise, returns None.
+    """
+    for path in paths:
+        trial_exe_path = os.path.join(path, exe_basename)
+        if os.path.exists(trial_exe_path):
+            return os.path.normcase(trial_exe_path)
+    return None
+
+
+def find_swig_executable(options):
+    """Finds the swig executable in the PATH or known good locations.
+
+    Replaces options.swig_executable with the full swig executable path.
+    """
+    # Figure out what we're looking for.
+    if platform.system() == 'Windows':
+        exe_basename = "swig.exe"
+        extra_dirs = []
+    else:
+        exe_basename = "swig"
+        extra_dirs = ["/usr/local/bin"]
+
+    # Figure out what paths to check.
+    path_env = os.environ.get("PATH", None)
+    if path_env is not None:
+        paths_to_check = path_env.split(os.path.pathsep)
+    else:
+        paths_to_check = []
+
+    # Add in the extra dirs
+    paths_to_check.extend(extra_dirs)
+    if len(paths_to_check) < 1:
+        logging.error(
+            "swig executable was not specified, PATH has no "
+            "contents, and there are no extra directories to search")
+        sys.exit(-6)
+
+    # Find the swig executable
+    options.swig_executable = find_file_in_paths(paths_to_check, exe_basename)
+    if not options.swig_executable or len(options.swig_executable) < 1:
+        logging.error(
+            "failed to find exe='%s' in paths='%s'",
+            exe_basename,
+            paths_to_check)
+        sys.exit(-6)
+    logging.info("found swig executable: %s", options.swig_executable)
+
+
 def main(args):
     """Drives the main script preparation steps.
 
@@ -179,6 +244,17 @@ def main(args):
     options = process_args(args)
     logging.debug("Processed args: options=%s", options)
 
+    # Ensure we have a swig executable.
+    if not options.swig_executable or len(options.swig_executable) == 0:
+        if options.find_swig:
+            find_swig_executable(options)
+        else:
+            logging.error(
+                "The --find-swig option must be specified "
+                "when the swig executable location is not "
+                "explicitly provided.")
+            sys.exit(-12)
+
     # Check if the swig file exists.
     swig_path = os.path.normcase(
         os.path.join(options.src_root, "scripts", "lldb.swig"))