diff --git a/src/fontra_compile/builder.py b/src/fontra_compile/builder.py
index e5a484b..67a9202 100644
--- a/src/fontra_compile/builder.py
+++ b/src/fontra_compile/builder.py
@@ -702,6 +702,12 @@ def prepareXAdvanceVariations(glyph: VariableGlyph, glyphSources):
     return [glyph.layers[source.layerName].glyph.xAdvance for source in glyphSources]
 
 
+def computeLeftSideBearing(path: Path | PackedPath, useTightBounds: bool) -> int:
+    boundsPen = (BoundsPen if useTightBounds else ControlBoundsPen)(None)
+    path.drawPoints(PointToSegmentPen(boundsPen))
+    return otRound(boundsPen.bounds[0]) if boundsPen.bounds is not None else 0
+
+
 def buildTTGlyph(glyph, glyphSources, defaultLayerGlyph, model):
     ttGlyphPen = TTGlyphPointPen(None)
     defaultLayerGlyph.path.drawPoints(ttGlyphPen)
@@ -781,12 +787,6 @@ def buildCharString(glyph, glyphSources, defaultLayerGlyph, model):
     return charString, charStringSupports
 
 
-def computeLeftSideBearing(path: Path | PackedPath, useTightBounds: bool) -> int:
-    boundsPen = (BoundsPen if useTightBounds else ControlBoundsPen)(None)
-    path.drawPoints(PointToSegmentPen(boundsPen))
-    return otRound(boundsPen.bounds[0]) if boundsPen.bounds is not None else 0
-
-
 def prepareCFFVarData(charStrings, charStringSupports):
     vsindexMap = {}
     for supports in charStringSupports.values():