lldb/scripts/msvc_extract_private_symbols.py

   1 """A tool for extracting a list of private lldb symbols to export for MSVC.
   2
   3 When exporting symbols from a dll or exe we either need to mark the symbols in
   4 the source code as __declspec(dllexport) or supply a list of symbols to the
   5 linker. Private symbols in LLDB don't explicitly specific dllexport, so we
   6 automate that by examining the symbol table.
   7 """
   8
   9 import argparse
  10 import os
  11 import re
  12 import subprocess
  13 import sys
  14
  15
  16 def extract_symbols(nm_path: str, lib: str):
  17     """Extract all of the private lldb symbols from the given path to llvm-nm and
  18     library to extract from."""
  19
  20     # Matches mangled symbols containing 'lldb_private'.
  21     lldb_sym_re = r"[0-9a-zA-Z]* [BT] (?P<symbol>[?]+[^?].*lldb_private.*)"
  22
  23     # '-g' means we only get global symbols.
  24     # '-p' do not waste time sorting the symbols.
  25     process = subprocess.Popen(
  26         [nm_path, "-g", "-p", lib],
  27         bufsize=1,
  28         stdout=subprocess.PIPE,
  29         stdin=subprocess.PIPE,
  30         universal_newlines=True,
  31     )
  32     process.stdin.close()
  33
  34     lldb_symbols = set()
  35     for line in process.stdout:
  36         match = re.match(lldb_sym_re, line)
  37         if match:
  38             symbol = match.group("symbol")
  39             assert (
  40                 symbol.count(" ") == 0
  41             ), "Regex matched too much, probably got undecorated name as well"
  42             # Deleting destructors start with ?_G or ?_E and can be discarded
  43             # because link.exe gives you a warning telling you they can't be
  44             # exported if you don't.
  45             if symbol.startswith("??_G") or symbol.startswith("??_E"):
  46                 continue
  47             lldb_symbols.add(symbol)
  48
  49     return lldb_symbols
  50
  51
  52 def main():
  53     parser = argparse.ArgumentParser(description="Generate LLDB dll exports")
  54     parser.add_argument(
  55         "-o", metavar="file", type=str, help="The name of the resultant export file."
  56     )
  57     parser.add_argument("--nm", help="Path to the llvm-nm executable.")
  58     parser.add_argument(
  59         "libs",
  60         metavar="lib",
  61         type=str,
  62         nargs="+",
  63         help="The libraries to extract symbols from.",
  64     )
  65     args = parser.parse_args()
  66
  67     # Get the list of libraries to extract symbols from
  68     libs = list()
  69     for lib in args.libs:
  70         # When invoked by cmake the arguments are the cmake target names of the
  71         # libraries, so we need to add .lib/.a to the end and maybe lib to the
  72         # start to get the filename. Also allow objects.
  73         suffixes = [".lib", ".a", ".obj", ".o"]
  74         if not any([lib.endswith(s) for s in suffixes]):
  75             for suffix in suffixes:
  76                 if os.path.exists(lib + suffix):
  77                     lib = lib + suffix
  78                     break
  79                 if os.path.exists("lib" + lib + suffix):
  80                     lib = "lib" + lib + suffix
  81                     break
  82         if not any([lib.endswith(s) for s in suffixes]):
  83             print(
  84                 "Unknown extension type for library argument: " + lib, file=sys.stderr
  85             )
  86             exit(1)
  87         libs.append(lib)
  88
  89     # Extract symbols from the input libraries.
  90     symbols = set()
  91     for lib in libs:
  92         for sym in list(extract_symbols(args.nm, lib)):
  93             symbols.add(sym)
  94
  95     # Write out the symbols to the output file.
  96     with open(args.o, "w", newline="") as f:
  97         for s in sorted(symbols):
  98             f.write(f"{s}\n")
  99
 100
 101 if __name__ == "__main__":
 102     main()