Fix duplicate addition of LLVM header

LLVMImporter.py

@@ -33,7 +33,7 @@
     get_generation_timestamp,
     src_matches_old_src,
     include_file,
-    gen_c_doxygen,
+    gen_c_doxygen, get_delimiter_line,
 )
 import PluginInfo
 import HexagonArchInfo
@@ -504,6 +504,11 @@ def add_license_info_header(self) -> None:
                 with open(p, "r+") as f:
                     content = f.read()
                     f.seek(0, 0)
+
+                    # If header message is there, skip it.
+                    match = re.search(get_delimiter_line(), content)
+                    if match:
+                        content = content[match.start():]
                     f.write(get_license() + "\n" + get_generation_timestamp(self.config) + "\n" + content)
                 if p not in self.edited_files:
                     log("Write {}".format(p), LogLevel.INFO)

helperFunctions.py

@@ -242,9 +242,13 @@ def set_pos_after_license(file: TextIO) -> None:
     return
 
 
+def get_delimiter_line() -> str:
+    return "{}\n".format(PluginInfo.GENERATION_WARNING_DELIMITER)
+
+
 def get_generation_warning_c_code() -> str:
     url = PluginInfo.REPO_URL
-    msg = "{}\n".format(PluginInfo.GENERATION_WARNING_DELIMITER)
+    msg = get_delimiter_line()
     msg += "// The following code is generated.\n"
     msg += "// Do not edit. Repository of code generator:\n"
     msg += "// {}\n".format(url)