line-directive: Stop expanding response files

`line-directive` was expanding response files for the swiftc invocation,
which was causing issues on CI when the file list got too long. This
changes the script to stop expanding response files and pass them as-is
to the swiftc invocation instead. The format for the response files was
also incorrect, with each individual file being quoted, so this fixes
the CMake script generating those.
Finally, this changes `line-directive` to dump the command line on
failure.

Author: Steelskin

stdlib/cmake/modules/SwiftSource.cmake

@@ -1015,13 +1015,13 @@ function(_compile_swift_files
   # need to work around this by avoiding long command line arguments. This can
   # be achieved by writing the list of file paths to a file, then reading that
   # list in the Python script.
-  string(REPLACE ";" "'\n'" source_files_quoted "${source_files}")
-  string(SHA1 file_name "'${source_files_quoted}'")
+  string(REPLACE ";" "\n" source_files_quoted "${source_files}")
+  string(SHA1 file_name "${source_files_quoted}")
   set(file_path_target "filelist-${file_name}")
   set(file_path "${CMAKE_CURRENT_BINARY_DIR}/${file_name}.txt")
 
   if (NOT TARGET ${file_path_target})
-    file(WRITE "${file_path}.tmp" "'${source_files_quoted}'")
+    file(WRITE "${file_path}.tmp" "${source_files_quoted}")
     add_custom_command_target(unused_var
       COMMAND ${CMAKE_COMMAND} -E copy_if_different "${file_path}.tmp" "${file_path}"
       CUSTOM_TARGET_NAME ${file_path_target}

utils/line-directive

@@ -211,8 +211,7 @@ def read_response_file(file_path):
         # "Make an iterator out of shlex.shlex.get_token, then consume items
         # until it returns None." (Then eagerly convert the result to a list so
         # that we can close the file.)
-        return list(iter(shlex.shlex(files, file_path, posix=True).get_token,
-                         None))
+        return [line.strip() for line in files if line.strip()]
 
 
 def expand_response_files(files):
@@ -686,13 +685,18 @@ def run():
         command_args = expand_response_files(sys.argv[dashes + 1:])
         command_args[0] = os.path.normpath(command_args[0])
 
-        command = subprocess.Popen(
-            command_args,
-            stderr=subprocess.STDOUT,
-            stdout=subprocess.PIPE,
-            universal_newlines=True,
-            encoding='UTF-8'
-        )
+        try:
+            command = subprocess.Popen(
+                command_args,
+                stderr=subprocess.STDOUT,
+                stdout=subprocess.PIPE,
+                universal_newlines=True,
+                encoding='UTF-8'
+            )
+        except Exception as e:
+            sys.stderr.write(f"Error executing command: {e}\n")
+            sys.stderr.write(f"Command: {' '.join(shlex.quote(arg) for arg in command_args)}\n")
+            sys.exit(1)
 
         sources = '(?P<file>' + '|'.join(re.escape(s) for s in sources) + ')'
 
@@ -731,7 +735,12 @@ def run():
                         m.group('tail'))
             sys.stdout.write(output)
 
-        sys.exit(command.wait())
+        exit_code = command.wait()
+        if exit_code != 0:
+            sys.stderr.write(f"Command failed with exit code {exit_code}\n")
+            sys.stderr.write(f"Command: {' '.join(shlex.quote(arg) for arg in command_args)}\n")
+
+        sys.exit(exit_code)
 
 
 if __name__ == '__main__':