diff --git a/tools/gn2bp/gn_utils.py b/tools/gn2bp/gn_utils.py
new file mode 100644
index 0000000..91d7a32
--- /dev/null
+++ b/tools/gn2bp/gn_utils.py
@@ -0,0 +1,525 @@
+# Copyright (C) 2022 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# A collection of utilities for extracting build rule information from GN
+# projects.
+
+from __future__ import print_function
+import collections
+import errno
+import filecmp
+import json
+import os
+import re
+import shutil
+import subprocess
+import sys
+from compat import iteritems
+
+BUILDFLAGS_TARGET = '//gn:gen_buildflags'
+GEN_VERSION_TARGET = '//src/base:version_gen_h'
+TARGET_TOOLCHAIN = '//gn/standalone/toolchain:gcc_like_host'
+HOST_TOOLCHAIN = '//gn/standalone/toolchain:gcc_like_host'
+LINKER_UNIT_TYPES = ('executable', 'shared_library', 'static_library')
+
+# TODO(primiano): investigate these, they require further componentization.
+ODR_VIOLATION_IGNORE_TARGETS = {
+    '//test/cts:perfetto_cts_deps',
+    '//:perfetto_integrationtests',
+}
+
+
+def _check_command_output(cmd, cwd):
+  try:
+    output = subprocess.check_output(cmd, stderr=subprocess.STDOUT, cwd=cwd)
+  except subprocess.CalledProcessError as e:
+    print(
+        'Command "{}" failed in {}:'.format(' '.join(cmd), cwd),
+        file=sys.stderr)
+    print(e.output.decode(), file=sys.stderr)
+    sys.exit(1)
+  else:
+    return output.decode()
+
+
+def repo_root():
+  """Returns an absolute path to the repository root."""
+  return os.path.join(
+      os.path.realpath(os.path.dirname(__file__)), os.path.pardir)
+
+
+def _tool_path(name, system_buildtools=False):
+  # Pass-through to use name if the caller requests to use the system
+  # toolchain.
+  if system_buildtools:
+    return [name]
+  wrapper = os.path.abspath(
+      os.path.join(repo_root(), 'tools', 'run_buildtools_binary.py'))
+  return ['python3', wrapper, name]
+
+
+def prepare_out_directory(gn_args,
+                          name,
+                          root=repo_root(),
+                          system_buildtools=False):
+  """Creates the JSON build description by running GN.
+
+    Returns (path, desc) where |path| is the location of the output directory
+    and |desc| is the JSON build description.
+    """
+  out = os.path.join(root, 'out', name)
+  try:
+    os.makedirs(out)
+  except OSError as e:
+    if e.errno != errno.EEXIST:
+      raise
+  _check_command_output(
+      _tool_path('gn', system_buildtools) +
+      ['gen', out, '--args=%s' % gn_args],
+      cwd=repo_root())
+  return out
+
+
+def load_build_description(out, system_buildtools=False):
+  """Creates the JSON build description by running GN."""
+  desc = _check_command_output(
+      _tool_path('gn', system_buildtools) +
+      ['desc', out, '--format=json', '--all-toolchains', '//*'],
+      cwd=repo_root())
+  return json.loads(desc)
+
+
+def create_build_description(gn_args, root=repo_root()):
+  """Prepares a GN out directory and loads the build description from it.
+
+    The temporary out directory is automatically deleted.
+    """
+  out = prepare_out_directory(gn_args, 'tmp.gn_utils', root=root)
+  try:
+    return load_build_description(out)
+  finally:
+    shutil.rmtree(out)
+
+
+def build_targets(out, targets, quiet=False, system_buildtools=False):
+  """Runs ninja to build a list of GN targets in the given out directory.
+
+    Compiling these targets is required so that we can include any generated
+    source files in the amalgamated result.
+    """
+  targets = [t.replace('//', '') for t in targets]
+  with open(os.devnull, 'w') as devnull:
+    stdout = devnull if quiet else None
+    cmd = _tool_path('ninja', system_buildtools) + targets
+    subprocess.check_call(cmd, cwd=os.path.abspath(out), stdout=stdout)
+
+
+def compute_source_dependencies(out, system_buildtools=False):
+  """For each source file, computes a set of headers it depends on."""
+  ninja_deps = _check_command_output(
+      _tool_path('ninja', system_buildtools) + ['-t', 'deps'], cwd=out)
+  deps = {}
+  current_source = None
+  for line in ninja_deps.split('\n'):
+    filename = os.path.relpath(os.path.join(out, line.strip()), repo_root())
+    if not line or line[0] != ' ':
+      current_source = None
+      continue
+    elif not current_source:
+      # We're assuming the source file is always listed before the
+      # headers.
+      assert os.path.splitext(line)[1] in ['.c', '.cc', '.cpp', '.S']
+      current_source = filename
+      deps[current_source] = []
+    else:
+      assert current_source
+      deps[current_source].append(filename)
+  return deps
+
+
+def label_to_path(label):
+  """Turn a GN output label (e.g., //some_dir/file.cc) into a path."""
+  assert label.startswith('//')
+  return label[2:]
+
+
+def label_without_toolchain(label):
+  """Strips the toolchain from a GN label.
+
+    Return a GN label (e.g //buildtools:protobuf(//gn/standalone/toolchain:
+    gcc_like_host) without the parenthesised toolchain part.
+    """
+  return label.split('(')[0]
+
+
+def label_to_target_name_with_path(label):
+  """
+  Turn a GN label into a target name involving the full path.
+  e.g., //src/perfetto:tests -> src_perfetto_tests
+  """
+  name = re.sub(r'^//:?', '', label)
+  name = re.sub(r'[^a-zA-Z0-9_]', '_', name)
+  return name
+
+
+def gen_buildflags(gn_args, target_file):
+  """Generates the perfetto_build_flags.h for the given config.
+
+    target_file: the path, relative to the repo root, where the generated
+        buildflag header will be copied into.
+    """
+  tmp_out = prepare_out_directory(gn_args, 'tmp.gen_buildflags')
+  build_targets(tmp_out, [BUILDFLAGS_TARGET], quiet=True)
+  src = os.path.join(tmp_out, 'gen', 'build_config', 'perfetto_build_flags.h')
+  shutil.copy(src, os.path.join(repo_root(), target_file))
+  shutil.rmtree(tmp_out)
+
+
+def check_or_commit_generated_files(tmp_files, check):
+  """Checks that gen files are unchanged or renames them to the final location
+
+    Takes in input a list of 'xxx.swp' files that have been written.
+    If check == False, it renames xxx.swp -> xxx.
+    If check == True, it just checks that the contents of 'xxx.swp' == 'xxx'.
+    Returns 0 if no diff was detected, 1 otherwise (to be used as exit code).
+    """
+  res = 0
+  for tmp_file in tmp_files:
+    assert (tmp_file.endswith('.swp'))
+    target_file = os.path.relpath(tmp_file[:-4])
+    if check:
+      if not filecmp.cmp(tmp_file, target_file):
+        sys.stderr.write('%s needs to be regenerated\n' % target_file)
+        res = 1
+      os.unlink(tmp_file)
+    else:
+      os.rename(tmp_file, target_file)
+  return res
+
+
+class ODRChecker(object):
+  """Detects ODR violations in linker units
+
+  When we turn GN source sets into Soong & Bazel file groups, there is the risk
+  to create ODR violations by including the same file group into different
+  linker unit (this is because other build systems don't have a concept
+  equivalent to GN's source_set). This class navigates the transitive
+  dependencies (mostly static libraries) of a target and detects if multiple
+  paths end up including the same file group. This is to avoid situations like:
+
+  traced.exe -> base(file group)
+  traced.exe -> libperfetto(static lib) -> base(file group)
+  """
+
+  def __init__(self, gn, target_name):
+    self.gn = gn
+    self.root = gn.get_target(target_name)
+    self.source_sets = collections.defaultdict(set)
+    self.deps_visited = set()
+    self.source_set_hdr_only = {}
+
+    self._visit(target_name)
+    num_violations = 0
+    if target_name in ODR_VIOLATION_IGNORE_TARGETS:
+      return
+    for sset, paths in self.source_sets.items():
+      if self.is_header_only(sset):
+        continue
+      if len(paths) != 1:
+        num_violations += 1
+        print(
+            'ODR violation in target %s, multiple paths include %s:\n  %s' %
+            (target_name, sset, '\n  '.join(paths)),
+            file=sys.stderr)
+    if num_violations > 0:
+      raise Exception('%d ODR violations detected. Build generation aborted' %
+                      num_violations)
+
+  def _visit(self, target_name, parent_path=''):
+    target = self.gn.get_target(target_name)
+    path = ((parent_path + ' > ') if parent_path else '') + target_name
+    if not target:
+      raise Exception('Cannot find target %s' % target_name)
+    for ssdep in target.source_set_deps:
+      name_and_path = '%s (via %s)' % (target_name, path)
+      self.source_sets[ssdep].add(name_and_path)
+    deps = set(target.deps).union(
+        target.transitive_proto_deps) - self.deps_visited
+    for dep_name in deps:
+      dep = self.gn.get_target(dep_name)
+      if dep.type == 'executable':
+        continue  # Execs are strong boundaries and don't cause ODR violations.
+      # static_library dependencies should reset the path. It doesn't matter if
+      # we get to a source file via:
+      # source_set1 > static_lib > source.cc OR
+      # source_set1 > source_set2 > static_lib > source.cc
+      # This is NOT an ODR violation because source.cc is linked from the same
+      # static library
+      next_parent_path = path if dep.type != 'static_library' else ''
+      self.deps_visited.add(dep_name)
+      self._visit(dep_name, next_parent_path)
+
+  def is_header_only(self, source_set_name):
+    cached = self.source_set_hdr_only.get(source_set_name)
+    if cached is not None:
+      return cached
+    target = self.gn.get_target(source_set_name)
+    if target.type != 'source_set':
+      raise TypeError('%s is not a source_set' % source_set_name)
+    res = all(src.endswith('.h') for src in target.sources)
+    self.source_set_hdr_only[source_set_name] = res
+    return res
+
+
+class GnParser(object):
+  """A parser with some cleverness for GN json desc files
+
+    The main goals of this parser are:
+    1) Deal with the fact that other build systems don't have an equivalent
+       notion to GN's source_set. Conversely to Bazel's and Soong's filegroups,
+       GN source_sets expect that dependencies, cflags and other source_set
+       properties propagate up to the linker unit (static_library, executable or
+       shared_library). This parser simulates the same behavior: when a
+       source_set is encountered, some of its variables (cflags and such) are
+       copied up to the dependent targets. This is to allow gen_xxx to create
+       one filegroup for each source_set and then squash all the other flags
+       onto the linker unit.
+    2) Detect and special-case protobuf targets, figuring out the protoc-plugin
+       being used.
+    """
+
+  class Target(object):
+    """Reperesents A GN target.
+
+        Maked properties are propagated up the dependency chain when a
+        source_set dependency is encountered.
+        """
+
+    def __init__(self, name, type):
+      self.name = name  # e.g. //src/ipc:ipc
+
+      VALID_TYPES = ('static_library', 'shared_library', 'executable', 'group',
+                     'action', 'source_set', 'proto_library')
+      assert (type in VALID_TYPES)
+      self.type = type
+      self.testonly = False
+      self.toolchain = None
+
+      # These are valid only for type == proto_library.
+      # This is typically: 'proto', 'protozero', 'ipc'.
+      self.proto_plugin = None
+      self.proto_paths = set()
+      self.proto_exports = set()
+
+      self.sources = set()
+      # TODO(primiano): consider whether the public section should be part of
+      # bubbled-up sources.
+      self.public_headers = set()  # 'public'
+
+      # These are valid only for type == 'action'
+      self.inputs = set()
+      self.outputs = set()
+      self.script = None
+      self.args = []
+
+      # These variables are propagated up when encountering a dependency
+      # on a source_set target.
+      self.cflags = set()
+      self.defines = set()
+      self.deps = set()
+      self.libs = set()
+      self.include_dirs = set()
+      self.ldflags = set()
+      self.source_set_deps = set()  # Transitive set of source_set deps.
+      self.proto_deps = set()
+      self.transitive_proto_deps = set()
+
+      # Deps on //gn:xxx have this flag set to True. These dependencies
+      # are special because they pull third_party code from buildtools/.
+      # We don't want to keep recursing into //buildtools in generators,
+      # this flag is used to stop the recursion and create an empty
+      # placeholder target once we hit //gn:protoc or similar.
+      self.is_third_party_dep_ = False
+
+    def __lt__(self, other):
+      if isinstance(other, self.__class__):
+        return self.name < other.name
+      raise TypeError(
+          '\'<\' not supported between instances of \'%s\' and \'%s\'' %
+          (type(self).__name__, type(other).__name__))
+
+    def __repr__(self):
+      return json.dumps({
+          k: (list(sorted(v)) if isinstance(v, set) else v)
+          for (k, v) in iteritems(self.__dict__)
+      },
+                        indent=4,
+                        sort_keys=True)
+
+    def update(self, other):
+      for key in ('cflags', 'defines', 'deps', 'include_dirs', 'ldflags',
+                  'source_set_deps', 'proto_deps', 'transitive_proto_deps',
+                  'libs', 'proto_paths'):
+        self.__dict__[key].update(other.__dict__.get(key, []))
+
+  def __init__(self, gn_desc):
+    self.gn_desc_ = gn_desc
+    self.all_targets = {}
+    self.linker_units = {}  # Executables, shared or static libraries.
+    self.source_sets = {}
+    self.actions = {}
+    self.proto_libs = {}
+
+  def get_target(self, gn_target_name):
+    """Returns a Target object from the fully qualified GN target name.
+
+        It bubbles up variables from source_set dependencies as described in the
+        class-level comments.
+        """
+    target = self.all_targets.get(gn_target_name)
+    if target is not None:
+      return target  # Target already processed.
+
+    desc = self.gn_desc_[gn_target_name]
+    target = GnParser.Target(gn_target_name, desc['type'])
+    target.testonly = desc.get('testonly', False)
+    target.toolchain = desc.get('toolchain', None)
+    self.all_targets[gn_target_name] = target
+
+    # We should never have GN targets directly depend on buidtools. They
+    # should hop via //gn:xxx, so we can give generators an opportunity to
+    # override them.
+    assert (not gn_target_name.startswith('//buildtools'))
+
+    # Don't descend further into third_party targets. Genrators are supposed
+    # to either ignore them or route to other externally-provided targets.
+    if gn_target_name.startswith('//gn'):
+      target.is_third_party_dep_ = True
+      return target
+
+    proto_target_type, proto_desc = self.get_proto_target_type(target)
+    if proto_target_type is not None:
+      self.proto_libs[target.name] = target
+      target.type = 'proto_library'
+      target.proto_plugin = proto_target_type
+      target.proto_paths.update(self.get_proto_paths(proto_desc))
+      target.proto_exports.update(self.get_proto_exports(proto_desc))
+      target.sources.update(proto_desc.get('sources', []))
+      assert (all(x.endswith('.proto') for x in target.sources))
+    elif target.type == 'source_set':
+      self.source_sets[gn_target_name] = target
+      target.sources.update(desc.get('sources', []))
+    elif target.type in LINKER_UNIT_TYPES:
+      self.linker_units[gn_target_name] = target
+      target.sources.update(desc.get('sources', []))
+    elif target.type == 'action':
+      self.actions[gn_target_name] = target
+      target.inputs.update(desc.get('inputs', []))
+      target.sources.update(desc.get('sources', []))
+      outs = [re.sub('^//out/.+?/gen/', '', x) for x in desc['outputs']]
+      target.outputs.update(outs)
+      target.script = desc['script']
+      # Args are typically relative to the root build dir (../../xxx)
+      # because root build dir is typically out/xxx/).
+      target.args = [re.sub('^../../', '//', x) for x in desc['args']]
+
+    # Default for 'public' is //* - all headers in 'sources' are public.
+    # TODO(primiano): if a 'public' section is specified (even if empty), then
+    # the rest of 'sources' is considered inaccessible by gn. Consider
+    # emulating that, so that generated build files don't end up with overly
+    # accessible headers.
+    public_headers = [x for x in desc.get('public', []) if x != '*']
+    target.public_headers.update(public_headers)
+
+    target.cflags.update(desc.get('cflags', []) + desc.get('cflags_cc', []))
+    target.libs.update(desc.get('libs', []))
+    target.ldflags.update(desc.get('ldflags', []))
+    target.defines.update(desc.get('defines', []))
+    target.include_dirs.update(desc.get('include_dirs', []))
+
+    # Recurse in dependencies.
+    for dep_name in desc.get('deps', []):
+      dep = self.get_target(dep_name)
+      if dep.is_third_party_dep_:
+        target.deps.add(dep_name)
+      elif dep.type == 'proto_library':
+        target.proto_deps.add(dep_name)
+        target.transitive_proto_deps.add(dep_name)
+        target.proto_paths.update(dep.proto_paths)
+        target.transitive_proto_deps.update(dep.transitive_proto_deps)
+      elif dep.type == 'source_set':
+        target.source_set_deps.add(dep_name)
+        target.update(dep)  # Bubble up source set's cflags/ldflags etc.
+      elif dep.type == 'group':
+        target.update(dep)  # Bubble up groups's cflags/ldflags etc.
+      elif dep.type == 'action':
+        if proto_target_type is None:
+          target.deps.add(dep_name)
+      elif dep.type in LINKER_UNIT_TYPES:
+        target.deps.add(dep_name)
+
+    return target
+
+  def get_proto_exports(self, proto_desc):
+    # exports in metadata will be available for source_set targets.
+    metadata = proto_desc.get('metadata', {})
+    return metadata.get('exports', [])
+
+  def get_proto_paths(self, proto_desc):
+    # import_dirs in metadata will be available for source_set targets.
+    metadata = proto_desc.get('metadata', {})
+    return metadata.get('import_dirs', [])
+
+  def get_proto_target_type(self, target):
+    """ Checks if the target is a proto library and return the plugin.
+
+        Returns:
+            (None, None): if the target is not a proto library.
+            (plugin, proto_desc) where |plugin| is 'proto' in the default (lite)
+            case or 'protozero' or 'ipc' or 'descriptor'; |proto_desc| is the GN
+            json desc of the target with the .proto sources (_gen target for
+            non-descriptor types or the target itself for descriptor type).
+        """
+    parts = target.name.split('(', 1)
+    name = parts[0]
+    toolchain = '(' + parts[1] if len(parts) > 1 else ''
+
+    # Descriptor targets don't have a _gen target; instead we look for the
+    # characteristic flag in the args of the target itself.
+    desc = self.gn_desc_.get(target.name)
+    if '--descriptor_set_out' in desc.get('args', []):
+      return 'descriptor', desc
+
+    # Source set proto targets have a non-empty proto_library_sources in the
+    # metadata of the description.
+    metadata = desc.get('metadata', {})
+    if 'proto_library_sources' in metadata:
+      return 'source_set', desc
+
+    # In all other cases, we want to look at the _gen target as that has the
+    # important information.
+    gen_desc = self.gn_desc_.get('%s_gen%s' % (name, toolchain))
+    if gen_desc is None or gen_desc['type'] != 'action':
+      return None, None
+    args = gen_desc.get('args', [])
+    if '/protoc' not in args[0]:
+      return None, None
+    plugin = 'proto'
+    for arg in (arg for arg in args if arg.startswith('--plugin=')):
+      # |arg| at this point looks like:
+      #  --plugin=protoc-gen-plugin=gcc_like_host/protozero_plugin
+      # or
+      #  --plugin=protoc-gen-plugin=protozero_plugin
+      plugin = arg.split('=')[-1].split('/')[-1].replace('_plugin', '')
+    return plugin, gen_desc