diff --git a/codebasin/__init__.py b/codebasin/__init__.py
index 909dc76..16d6ee5 100644
--- a/codebasin/__init__.py
+++ b/codebasin/__init__.py
@@ -10,7 +10,6 @@
 
 import codebasin.source
 import codebasin.util
-import codebasin.walkers
 
 warnings.warn(
     "Calling codebasin package internals is deprecated. "
diff --git a/codebasin/__main__.py b/codebasin/__main__.py
index edbb2b8..1683107 100755
--- a/codebasin/__main__.py
+++ b/codebasin/__main__.py
@@ -12,7 +12,6 @@
 import sys
 
 from codebasin import CodeBase, config, finder, report, util
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 log = logging.getLogger("codebasin")
 version = "1.2.0"
@@ -331,8 +330,7 @@ def _main():
     stdout_handler.setLevel(log_level)
 
     # Count lines for platforms
-    platform_mapper = PlatformMapper(codebase)
-    setmap = platform_mapper.walk(state)
+    setmap = state.get_setmap(codebase)
 
     def report_enabled(name):
         if "all" in args.reports:
diff --git a/codebasin/finder.py b/codebasin/finder.py
index 436951a..7154a68 100644
--- a/codebasin/finder.py
+++ b/codebasin/finder.py
@@ -12,8 +12,9 @@
 
 from tqdm import tqdm
 
-from codebasin import file_parser, platform, preprocessor
+from codebasin import CodeBase, file_parser, platform, preprocessor
 from codebasin.language import FileLanguage
+from codebasin.preprocessor import CodeNode
 from codebasin.walkers.tree_associator import TreeAssociator
 
 log = logging.getLogger(__name__)
@@ -88,6 +89,22 @@ def get_map(self, fn):
             return None
         return self.maps[fn]
 
+    def get_setmap(self, codebase: CodeBase) -> dict[frozenset, int]:
+        """
+        Returns
+        -------
+        dict[frozenset, int]
+            The number of lines associated with each platform set.
+        """
+        setmap = collections.defaultdict(int)
+        for fn in codebase:
+            tree = self.get_tree(fn)
+            association = self.get_map(fn)
+            for node in [n for n in tree.walk() if isinstance(n, CodeNode)]:
+                platform = frozenset(association[node])
+                setmap[platform] += node.num_lines
+        return setmap
+
 
 def find(
     rootdir,
diff --git a/codebasin/walkers/platform_mapper.py b/codebasin/walkers/platform_mapper.py
deleted file mode 100644
index 753a1ae..0000000
--- a/codebasin/walkers/platform_mapper.py
+++ /dev/null
@@ -1,38 +0,0 @@
-# Copyright (C) 2019-2024 Intel Corporation
-# SPDX-License-Identifier: BSD-3-Clause
-
-import logging
-
-from codebasin.preprocessor import CodeNode, FileNode
-from codebasin.walkers.tree_mapper import TreeMapper
-
-log = logging.getLogger("codebasin")
-
-
-class PlatformMapper(TreeMapper):
-    """
-    Specific TreeMapper that builds a mapping of nodes to platforms.
-    """
-
-    def __init__(self, codebase, _tree=None, _node_associations=None):
-        super().__init__(_tree, _node_associations)
-        self.codebase = codebase
-        self._null_set = frozenset([])
-
-    def _map_node(self, _node, _map):
-        """
-        Map a specific node to its platform set, and descend into the
-        children nodes.
-        """
-        # Do not map files that the user does not consider to be part of
-        # the codebase
-        if isinstance(_node, FileNode) and _node.filename not in self.codebase:
-            return
-
-        if isinstance(_node, CodeNode):
-            association = _map[_node]
-            platform = frozenset(association)
-            self.line_map[platform] += _node.num_lines
-
-        for child in _node.children:
-            self._map_node(child, _map)
diff --git a/tests/basic_asm/test_basic_asm.py b/tests/basic_asm/test_basic_asm.py
index a3bef31..202a080 100644
--- a/tests/basic_asm/test_basic_asm.py
+++ b/tests/basic_asm/test_basic_asm.py
@@ -6,7 +6,6 @@
 from pathlib import Path
 
 from codebasin import CodeBase, finder
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 
 class TestBasicAsm(unittest.TestCase):
@@ -35,8 +34,7 @@ def test_yaml(self):
             )
         configuration = {"CPU": entries}
         state = finder.find(self.rootdir, codebase, configuration)
-        mapper = PlatformMapper(codebase)
-        setmap = mapper.walk(state)
+        setmap = state.get_setmap(codebase)
         self.assertDictEqual(
             setmap,
             self.expected_setmap,
diff --git a/tests/basic_fortran/test_basic_fortran.py b/tests/basic_fortran/test_basic_fortran.py
index e3a244a..29de5f4 100644
--- a/tests/basic_fortran/test_basic_fortran.py
+++ b/tests/basic_fortran/test_basic_fortran.py
@@ -6,7 +6,6 @@
 from pathlib import Path
 
 from codebasin import CodeBase, finder
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 
 class TestBasicFortran(unittest.TestCase):
@@ -46,8 +45,7 @@ def test_yaml(self):
             ],
         }
         state = finder.find(self.rootdir, codebase, configuration)
-        mapper = PlatformMapper(codebase)
-        setmap = mapper.walk(state)
+        setmap = state.get_setmap(codebase)
         self.assertDictEqual(
             setmap,
             self.expected_setmap,
diff --git a/tests/build-dir/test_build_dir.py b/tests/build-dir/test_build_dir.py
index 95b46ba..6626109 100644
--- a/tests/build-dir/test_build_dir.py
+++ b/tests/build-dir/test_build_dir.py
@@ -8,7 +8,6 @@
 from pathlib import Path
 
 from codebasin import CodeBase, config, finder
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 
 class TestBuildDirectories(unittest.TestCase):
@@ -64,8 +63,7 @@ def test_absolute_paths(self):
         expected_setmap = {frozenset(["one", "two"]): 1}
 
         state = finder.find(self.rootdir, codebase, configuration)
-        mapper = PlatformMapper(codebase)
-        setmap = mapper.walk(state)
+        setmap = state.get_setmap(codebase)
         self.assertDictEqual(setmap, expected_setmap, "Mismatch in setmap")
 
     def test_empty_platform(self):
diff --git a/tests/commented_directive/test_commented_directive.py b/tests/commented_directive/test_commented_directive.py
index 0ae12b9..dbb6210 100644
--- a/tests/commented_directive/test_commented_directive.py
+++ b/tests/commented_directive/test_commented_directive.py
@@ -6,7 +6,6 @@
 from pathlib import Path
 
 from codebasin import CodeBase, finder
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 
 class TestCommentedDirective(unittest.TestCase):
@@ -50,8 +49,7 @@ def test_yaml(self):
             ],
         }
         state = finder.find(self.rootdir, codebase, configuration)
-        mapper = PlatformMapper(codebase)
-        setmap = mapper.walk(state)
+        setmap = state.get_setmap(codebase)
 
         node_count = 1
         for fn in state.get_filenames():
diff --git a/tests/define/test_define.py b/tests/define/test_define.py
index b27aff5..5581ed7 100644
--- a/tests/define/test_define.py
+++ b/tests/define/test_define.py
@@ -6,7 +6,6 @@
 from pathlib import Path
 
 from codebasin import CodeBase, finder
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 
 class TestDefine(unittest.TestCase):
@@ -45,8 +44,7 @@ def test_yaml(self):
             ],
         }
         state = finder.find(self.rootdir, codebase, configuration)
-        mapper = PlatformMapper(codebase)
-        setmap = mapper.walk(state)
+        setmap = state.get_setmap(codebase)
         self.assertDictEqual(
             setmap,
             self.expected_setmap,
diff --git a/tests/disjoint/test_disjoint.py b/tests/disjoint/test_disjoint.py
index 1ec9b8c..0b7ecbe 100644
--- a/tests/disjoint/test_disjoint.py
+++ b/tests/disjoint/test_disjoint.py
@@ -6,7 +6,6 @@
 from pathlib import Path
 
 from codebasin import CodeBase, finder
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 
 class TestDisjointCodebase(unittest.TestCase):
@@ -44,8 +43,7 @@ def test_yaml(self):
             ],
         }
         state = finder.find(self.rootdir, codebase, configuration)
-        mapper = PlatformMapper(codebase)
-        setmap = mapper.walk(state)
+        setmap = state.get_setmap(codebase)
         self.assertDictEqual(
             setmap,
             self.expected_setmap,
diff --git a/tests/duplicates/test_duplicates.py b/tests/duplicates/test_duplicates.py
index ee5a940..e4ea97d 100644
--- a/tests/duplicates/test_duplicates.py
+++ b/tests/duplicates/test_duplicates.py
@@ -6,7 +6,6 @@
 from pathlib import Path
 
 from codebasin import CodeBase, finder
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 
 class TestDuplicates(unittest.TestCase):
@@ -48,8 +47,7 @@ def test_duplicates(self):
         expected_setmap = {frozenset(["cpu"]): 1, frozenset(["gpu"]): 1}
 
         state = finder.find(self.rootdir, codebase, configuration)
-        mapper = PlatformMapper(codebase)
-        setmap = mapper.walk(state)
+        setmap = state.get_setmap(codebase)
         self.assertDictEqual(setmap, expected_setmap, "Mismatch in setmap")
 
     def test_symlinks(self):
diff --git a/tests/exclude/test_exclude.py b/tests/exclude/test_exclude.py
index b640e17..7fecfe3 100644
--- a/tests/exclude/test_exclude.py
+++ b/tests/exclude/test_exclude.py
@@ -6,7 +6,6 @@
 from pathlib import Path
 
 from codebasin import CodeBase, config, finder
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 
 class TestExclude(unittest.TestCase):
@@ -28,8 +27,7 @@ def _get_setmap(self, excludes):
             "test": config.load_database(str(dbpath), str(self.rootdir)),
         }
         state = finder.find(self.rootdir, codebase, configuration)
-        mapper = PlatformMapper(codebase)
-        setmap = mapper.walk(state)
+        setmap = state.get_setmap(codebase)
         return setmap
 
     def test_exclude_nothing(self):
diff --git a/tests/include/test_include.py b/tests/include/test_include.py
index 65e38ad..27e298e 100644
--- a/tests/include/test_include.py
+++ b/tests/include/test_include.py
@@ -6,7 +6,6 @@
 from pathlib import Path
 
 from codebasin import CodeBase, config, finder
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 
 class TestInclude(unittest.TestCase):
@@ -37,8 +36,7 @@ def test_include(self):
         }
 
         state = finder.find(self.rootdir, codebase, configuration)
-        mapper = PlatformMapper(codebase)
-        setmap = mapper.walk(state)
+        setmap = state.get_setmap(codebase)
         self.assertDictEqual(
             setmap,
             self.expected_setmap,
diff --git a/tests/literals/test_literals.py b/tests/literals/test_literals.py
index 0a8b28d..b7e387d 100644
--- a/tests/literals/test_literals.py
+++ b/tests/literals/test_literals.py
@@ -6,7 +6,6 @@
 from pathlib import Path
 
 from codebasin import CodeBase, finder, preprocessor
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 
 class TestLiterals(unittest.TestCase):
@@ -43,8 +42,7 @@ def test_literals(self):
             ],
         }
         state = finder.find(self.rootdir, codebase, configuration)
-        mapper = PlatformMapper(codebase)
-        setmap = mapper.walk(state)
+        setmap = state.get_setmap(codebase)
         self.assertDictEqual(
             setmap,
             self.expected_setmap,
diff --git a/tests/macro_expansion/test_macro_expansion.py b/tests/macro_expansion/test_macro_expansion.py
index 5ad699b..da4ff9c 100644
--- a/tests/macro_expansion/test_macro_expansion.py
+++ b/tests/macro_expansion/test_macro_expansion.py
@@ -6,7 +6,6 @@
 from pathlib import Path
 
 from codebasin import CodeBase, finder, platform, preprocessor
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 
 class TestMacroExpansion(unittest.TestCase):
@@ -52,8 +51,7 @@ def test_macro_expansion(self):
             "GPU": gpu_entries,
         }
         state = finder.find(self.rootdir, codebase, configuration)
-        mapper = PlatformMapper(codebase)
-        setmap = mapper.walk(state)
+        setmap = state.get_setmap(codebase)
         self.assertDictEqual(
             setmap,
             self.expected_setmap,
diff --git a/tests/multi_line/test_multi_line.py b/tests/multi_line/test_multi_line.py
index 4b63a24..76a3b53 100644
--- a/tests/multi_line/test_multi_line.py
+++ b/tests/multi_line/test_multi_line.py
@@ -6,7 +6,6 @@
 from pathlib import Path
 
 from codebasin import CodeBase, finder
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 
 class TestMultiLine(unittest.TestCase):
@@ -45,8 +44,7 @@ def test_yaml(self):
             ],
         }
         state = finder.find(self.rootdir, codebase, configuration)
-        mapper = PlatformMapper(codebase)
-        setmap = mapper.walk(state)
+        setmap = state.get_setmap(codebase)
         self.assertDictEqual(
             setmap,
             self.expected_setmap,
diff --git a/tests/nesting/test_nesting.py b/tests/nesting/test_nesting.py
index 76966b9..32ae02a 100644
--- a/tests/nesting/test_nesting.py
+++ b/tests/nesting/test_nesting.py
@@ -6,7 +6,6 @@
 from pathlib import Path
 
 from codebasin import CodeBase, finder
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 
 class TestNesting(unittest.TestCase):
@@ -46,8 +45,7 @@ def test_yaml(self):
             ],
         }
         state = finder.find(self.rootdir, codebase, configuration)
-        mapper = PlatformMapper(codebase)
-        setmap = mapper.walk(state)
+        setmap = state.get_setmap(codebase)
         self.assertDictEqual(
             setmap,
             self.expected_setmap,
diff --git a/tests/once/test_once.py b/tests/once/test_once.py
index 0e5571a..c8e960b 100644
--- a/tests/once/test_once.py
+++ b/tests/once/test_once.py
@@ -6,7 +6,6 @@
 from pathlib import Path
 
 from codebasin import CodeBase, finder
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 
 class TestOnce(unittest.TestCase):
@@ -45,8 +44,7 @@ def test_yaml(self):
             ],
         }
         state = finder.find(self.rootdir, codebase, configuration)
-        mapper = PlatformMapper(codebase)
-        setmap = mapper.walk(state)
+        setmap = state.get_setmap(codebase)
         self.assertDictEqual(
             setmap,
             self.expected_setmap,
diff --git a/tests/operators/test_operators.py b/tests/operators/test_operators.py
index 7eba420..fb4011c 100644
--- a/tests/operators/test_operators.py
+++ b/tests/operators/test_operators.py
@@ -6,7 +6,6 @@
 from pathlib import Path
 
 from codebasin import CodeBase, finder, platform, preprocessor
-from codebasin.walkers.platform_mapper import PlatformMapper
 
 
 class TestOperators(unittest.TestCase):
@@ -43,8 +42,7 @@ def test_operators(self):
             ],
         }
         state = finder.find(self.rootdir, codebase, configuration)
-        mapper = PlatformMapper(codebase)
-        setmap = mapper.walk(state)
+        setmap = state.get_setmap(codebase)
         self.assertDictEqual(
             setmap,
             self.expected_setmap,