gdbinit

# Copyright 2018 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

python

import os
import subprocess
import sys

compile_dirs = set()
src_dir = None

def get_current_debug_file_directories():
  dir = gdb.execute("show debug-file-directory", to_string=True)
  dir = dir[
      len('The directory where separate debug symbols are searched for is "'
         ):-len('".') - 1]
  return set(dir.split(":"))


def add_debug_file_directory(dir):
  # gdb has no function to add debug-file-directory, simulates that by using
  # `show debug-file-directory` and `set debug-file-directory <directories>`.
  current_dirs = get_current_debug_file_directories()
  current_dirs.add(dir)
  gdb.execute(
      "set debug-file-directory %s" % ":".join(current_dirs), to_string=True)


def load_libcxx_pretty_printers(src_dir):
  libcxx_pretty_printers = os.path.join(src_dir, 'third_party', 'libc++', 'src',
                                        'utils', 'gdb', 'libcxx')
  if not os.path.isdir(libcxx_pretty_printers):
    return
  sys.path.insert(1, libcxx_pretty_printers)
  from printers import register_libcxx_printer_loader
  register_libcxx_printer_loader()


def load_gdb_chrome(src_dir):
  tools_gdb = os.path.join(src_dir, 'tools', 'gdb')

  sys.path.insert(1, tools_gdb)
  import gdb_chrome

  gdb.execute('source %s' % os.path.join(tools_gdb, 'viewg.gdb'))


def set_src_dir(compile_dir):
  global src_dir
  git = subprocess.Popen(
      ['git', '-C', compile_dir, 'rev-parse', '--show-toplevel'],
      stdout=subprocess.PIPE,
      stderr=subprocess.PIPE)
  src_dir, _ = git.communicate()
  if git.returncode:
    return
  if isinstance(src_dir, str):
    src_dir = src_dir.rstrip()
  else:
    src_dir = src_dir.decode('utf-8').rstrip()

  # If there's no chrome directory in the repo root, we got the wrong git repo.
  # The most common way to have this happen is to be in a git checkout of
  # another project that vendors chromium in its own third_party directory. In
  # that case, try falling back to the current working directory.
  if not os.path.isdir(os.path.join(src_dir, 'chrome')):
    src_dir = os.path.abspath(os.getcwd())

  load_libcxx_pretty_printers(src_dir)

  load_gdb_chrome(src_dir)


def newobj_handler(event):
  global compile_dirs
  compile_dir = os.path.dirname(event.new_objfile.filename)
  if not compile_dir:
    return
  if compile_dir in compile_dirs:
    return
  compile_dirs.add(compile_dir)

  # Add source path
  gdb.execute("dir %s" % compile_dir)

  # Need to tell the location of .dwo files.
  # https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html
  # https://crbug.com/603286#c35
  add_debug_file_directory(compile_dir)

  global src_dir
  if not src_dir:
    set_src_dir(compile_dir)


# Event hook for newly loaded objfiles.
# https://sourceware.org/gdb/onlinedocs/gdb/Events-In-Python.html
gdb.events.new_objfile.connect(newobj_handler)

gdb.execute("set environment CHROMIUM_GDBINIT_SOURCED=1")

# GDB 9.1 adds a setting, disabled by default, to do multithreaded symbol
# loading. This is a major speed up for Chrome, so turn it on here. We
# use try..except to avoid displaying errors in earlier GDB versions.
try:
  # unlimited means "number of cores"
  gdb.execute("maint set worker-threads unlimited")
except:
  pass

end