diff --git a/pw_bloat/BUILD.gn b/pw_bloat/BUILD.gn
index 2ae952c..8011fc2 100644
--- a/pw_bloat/BUILD.gn
+++ b/pw_bloat/BUILD.gn
@@ -30,6 +30,10 @@
   sources = [ "bloat_this_binary.cc" ] + public
 }
 
+source_set("base_main") {
+  sources = [ "base_main.cc" ]
+}
+
 # Standard minimal base binary for bloat reports.
 pw_executable("bloat_base") {
   forward_variables_from(pw_bloat_empty_base, "*")
diff --git a/pw_bloat/bloat.gni b/pw_bloat/bloat.gni
index c2e42a5..bb6a653 100644
--- a/pw_bloat/bloat.gni
+++ b/pw_bloat/bloat.gni
@@ -340,6 +340,8 @@
 # main() function that loads the bloat_this_binary library and does nothing
 # else.
 pw_bloat_empty_base = {
-  deps = [ "$dir_pw_bloat:bloat_this_binary" ]
-  sources = [ "$dir_pw_bloat/base_main.cc" ]
+  deps = [
+    "$dir_pw_bloat:base_main",
+    "$dir_pw_bloat:bloat_this_binary",
+  ]
 }
diff --git a/pw_fuzzer/BUILD.gn b/pw_fuzzer/BUILD.gn
index 6b67150..61271c3 100644
--- a/pw_fuzzer/BUILD.gn
+++ b/pw_fuzzer/BUILD.gn
@@ -77,6 +77,15 @@
   public_deps = [ "$dir_pw_log" ]
 }
 
+source_set("run_as_unit_test") {
+  configs = [ ":default_config" ]
+  sources = [ "pw_fuzzer_disabled.cc" ]
+  deps = [
+    dir_pw_log,
+    dir_pw_unit_test,
+  ]
+}
+
 # See https://llvm.org/docs/LibFuzzer.html#fuzzer-friendly-build-mode
 config("fuzzing_build_mode_unsafe_for_production") {
   defines = [ "FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION" ]
diff --git a/pw_fuzzer/fuzzer.gni b/pw_fuzzer/fuzzer.gni
index 101d4b1..fd19308 100644
--- a/pw_fuzzer/fuzzer.gni
+++ b/pw_fuzzer/fuzzer.gni
@@ -82,14 +82,7 @@
       forward_variables_from(invoker, "*", [ "visibility" ])
       forward_variables_from(invoker, [ "visibility" ])
       sources += [ "$dir_pw_fuzzer/pw_fuzzer_disabled.cc" ]
-      if (!defined(configs)) {
-        configs = []
-      }
-      configs += [ "$dir_pw_fuzzer:default_config" ]
-      deps += [
-        "$dir_pw_log",
-        "$dir_pw_unit_test",
-      ]
+      deps += [ "$dir_pw_fuzzer:run_as_unit_test" ]
     }
   }
 }
diff --git a/pw_preprocessor/BUILD.gn b/pw_preprocessor/BUILD.gn
index f8ca773..dff5a11 100644
--- a/pw_preprocessor/BUILD.gn
+++ b/pw_preprocessor/BUILD.gn
@@ -48,19 +48,22 @@
   ]
 }
 
-template("preprocessor_test") {
-  not_needed([ "invoker" ])
-  pw_test(target_name) {
-    deps = [ ":pw_preprocessor" ]
-    sources = [ "$target_name.cc" ]
-  }
+pw_test("boolean_test") {
+  deps = [ ":pw_preprocessor" ]
+  sources = [ "boolean_test.cc" ]
 }
 
-preprocessor_test("boolean_test") {
+pw_test("concat_test") {
+  deps = [ ":pw_preprocessor" ]
+  sources = [ "concat_test.cc" ]
 }
-preprocessor_test("concat_test") {
+
+pw_test("macro_arg_count_test") {
+  deps = [ ":pw_preprocessor" ]
+  sources = [ "macro_arg_count_test.cc" ]
 }
-preprocessor_test("macro_arg_count_test") {
-}
-preprocessor_test("util_test") {
+
+pw_test("util_test") {
+  deps = [ ":pw_preprocessor" ]
+  sources = [ "util_test.cc" ]
 }
diff --git a/pw_presubmit/py/pw_presubmit/build.py b/pw_presubmit/py/pw_presubmit/build.py
index 5d53b82..618f3a2 100644
--- a/pw_presubmit/py/pw_presubmit/build.py
+++ b/pw_presubmit/py/pw_presubmit/build.py
@@ -17,6 +17,7 @@
 import logging
 import os
 from pathlib import Path
+import re
 from typing import Container, Dict, Iterable, List, Mapping, Set, Tuple
 
 from pw_presubmit import call, log_run, plural, PresubmitFailure, tools
@@ -90,11 +91,26 @@
     return files
 
 
+# Finds string literals with '.' in them.
+_MAYBE_A_PATH = re.compile(r'"([^\n"]+\.[^\n"]+)"')
+
+
+def _search_files_for_paths(build_files: Iterable[Path]) -> Iterable[Path]:
+    for build_file in build_files:
+        directory = build_file.parent
+
+        for string in _MAYBE_A_PATH.finditer(build_file.read_text()):
+            path = directory / string.group(1)
+            if path.is_file():
+                yield path
+
+
 def check_builds_for_files(
         extensions_to_check: Container[str],
         files: Iterable[Path],
         bazel_dirs: Iterable[Path] = (),
         gn_dirs: Iterable[Tuple[Path, Path]] = (),
+        gn_build_files: Iterable[Path] = (),
 ) -> Dict[str, List[Path]]:
     """Checks that source files are in the GN and Bazel builds.
 
@@ -103,6 +119,7 @@
         files: the files that should be checked
         bazel_dirs: directories in which to run bazel query
         gn_dirs: (source_dir, output_dir) tuples with which to run gn desc
+        gn_build_files: paths to BUILD.gn files to directly search for paths
 
     Returns:
         a dictionary mapping build system ('Bazel' or 'GN' to a list of missing
@@ -123,6 +140,8 @@
         gn_builds.update(
             _get_paths_from_command(source_dir, 'gn', 'desc', output_dir, '*'))
 
+    gn_builds.update(_search_files_for_paths(gn_build_files))
+
     missing: Dict[str, List[Path]] = collections.defaultdict(list)
 
     for path in (p for p in files if p.suffix in extensions_to_check):
@@ -130,7 +149,7 @@
             # TODO(pwbug/176) Replace this workaround for fuzzers.
             if 'fuzz' not in str(path):
                 missing['Bazel'].append(path)
-        if gn_dirs and path not in gn_builds:
+        if (gn_dirs or gn_build_files) and path not in gn_builds:
             missing['GN'].append(path)
 
     for builder, paths in missing.items():
diff --git a/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py b/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py
index 8ef7136..b7ee2fc 100755
--- a/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py
+++ b/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py
@@ -32,7 +32,8 @@
         os.path.abspath(__file__))))
     import pw_presubmit
 
-from pw_presubmit import build, cli, environment, format_code, python_checks
+from pw_presubmit import build, cli, environment, format_code, git_repo
+from pw_presubmit import python_checks
 from pw_presubmit import call, filter_paths, PresubmitContext, PresubmitFailure
 from pw_presubmit import Programs
 from pw_presubmit.install_hook import install_hook
@@ -251,13 +252,12 @@
 @filter_paths(endswith=(*_SOURCES_IN_BUILD, 'BUILD', '.bzl', '.gn', '.gni'))
 def source_is_in_build_files(ctx: PresubmitContext):
     """Checks that source files are in the GN and Bazel builds."""
-    gn_path = ctx.output_dir.joinpath('default')
-    build.gn_gen(ctx.root, gn_path, pw_build_HOST_TOOLS='true')
-
-    missing = build.check_builds_for_files(_SOURCES_IN_BUILD,
-                                           ctx.paths,
-                                           bazel_dirs=[ctx.root],
-                                           gn_dirs=[(ctx.root, gn_path)])
+    missing = build.check_builds_for_files(
+        _SOURCES_IN_BUILD,
+        ctx.paths,
+        bazel_dirs=[ctx.root],
+        gn_build_files=git_repo.list_files(
+            pathspecs=['BUILD.gn', '*BUILD.gn']))
 
     if missing:
         _LOG.warning(