feat(precheck): add zeroarea check

precheck/precheck.py

@@ -87,6 +87,10 @@ def klayout_drc(gds: str, check: str, script=f"{PDK_NAME}_mr.drc"):
         )
 
 
+def klayout_zero_area(gds: str):
+    return klayout_drc(gds, "zero_area", "zeroarea.rb.drc")
+
+
 def klayout_checks(gds: str):
     layout = pya.Layout()
     layout.read(gds)
@@ -134,6 +138,7 @@ def main():
                 "pin_label_purposes_overlapping_drawing.rb.drc",
             ),
         ],
+        ["KLayout zero area", lambda: klayout_zero_area(args.gds)],
         ["KLayout Checks", lambda: klayout_checks(args.gds)],
     ]
 

precheck/reports/.gitignore

@@ -2,6 +2,7 @@ drc_beol.xml
 drc_feol.xml
 drc_offgrid.xml
 drc_pin_label_purposes_overlapping_drawing.xml
+drc_zero_area.xml
 magic_drc.mag
 magic_drc.txt
 results.md

precheck/tech-files/README.txt

@@ -1,2 +1,3 @@
 sky130A_mr.drc from https://github.com/efabless/mpw_precheck revision 4fd5283b124e931c9e71219f47270075176f84e2
 pin_label_purposes_overlapping_drawing.rb.drc from https://github.com/efabless/mpw_precheck revision f6b9c3d3f00694f96dce8444149449b4719180f0
+zeroarea.rb.drc from https://github.com/efabless/mpw_precheck revision 4fd5283b124e931c9e71219f47270075176f84e2

precheck/tech-files/zeroarea.rb.drc

@@ -0,0 +1,82 @@
+# based in part on: https://www.klayout.de/forum/discussion/173/use-klayout-in-batch-mode
+
+$errs = 0
+del = 0
+delZLp = true
+len0 = 0
+len0Del = 0
+
+ly = RBA::Layout.new
+source($input, $top_cell_name)
+ly.read($input)
+report("zero area check", $report)
+
+ly.layer_indices.each { |li|
+  ly.each_cell { |cell|
+    cell.shapes(li).each { |shape|
+      # TODO: must we check that shape is one of: box, polygon, path? What happens to text?
+      if shape.is_valid? && (!shape.is_null?) &&
+          (shape.is_box? || shape.is_path? || shape.is_polygon?) &&
+          shape.area == 0
+        $errs += 1
+        polygons().insert(shape.dpolygon).output("zero_area_shape")
+        if $cleaned_output
+          shape.delete
+          del += 1
+         end
+      elsif delZLp && shape.is_valid? && (!shape.is_null?) && shape.is_path?
+        # puts "path on layer:#{layer_info} area:#{shape.area}"
+        lastpt = nil
+        same = true
+        # walk the points. First time we identify at least two unique-points, skip: not a zero-length path.
+        shape.each_point { |pt|
+          if lastpt && lastpt != pt
+            same = false
+            break
+          end
+          lastpt = pt
+        }
+        if same
+          # puts "zero-length path on layer:#{layer_info} area:#{shape.area} path:#{shape.to_s}"
+          len0 += 1
+          $errs += 1
+          if $cleaned_output
+            shape.delete
+            len0Del += 1
+          end
+        end
+      end
+    }
+  }
+}
+
+if $cleaned_output
+  puts "writing to #{$cleaned_output}"
+  ly.write($cleaned_output)
+end
+
+puts "#{$errs} zero-area shapes"
+
+del += len0Del
+if delZLp
+  puts "#{len0} zero-length paths,  #{len0Del} zero-length paths deleted."
+end
+puts "#{$errs} total zero-area objects,  #{del} total objects deleted."
+
+# if we roll-over to 256, exit-status seen by shell is zero.
+# uncaught I/O errors will yield (built-in) exit status of 1.
+if $errs > 0
+  $errs = $errs + 1
+end
+if $errs > 127
+  $errs = 127
+end
+# experimental: report own peak process-stats. BUT: output-file isn't really written
+# until we exit (during exit). So these results are not 100% accurate.
+# VmHWM: max-resident-size, VmPeak: max virtual-size.
+# don't need: pid=Process.pid
+if   File.readable?("/proc/self/status")
+  puts File.foreach("/proc/self/status").grep(/^(VmPeak|VmHWM)/)
+end
+# does not work (to set exit-status) in 0.23.11. Does work in 0.24.2, 0.27.
+exit $errs

precheck/test_precheck.py

@@ -67,6 +67,20 @@ def gds_fail_metal5_poly(tmp_path_factory: pytest.TempPathFactory):
     return str(gds_file)
 
 
+@pytest.fixture(scope="session")
+def gds_zero_area(tmp_path_factory: pytest.TempPathFactory):
+    """Creates a GDS with a zero-area polygon."""
+    gds_file = tmp_path_factory.mktemp("gds") / "gds_zero_area.gds"
+    layout = pya.Layout()
+    top_cell = layout.create_cell("TEST_zero_area")
+    met1_info = gds_layers["met1.drawing"]
+    met1 = layout.layer(met1_info.layer, met1_info.data_type)
+    rect = pya.DBox(0, 0, 0, 0)
+    top_cell.shapes(met1).insert(rect)
+    layout.write(str(gds_file))
+    return str(gds_file)
+
+
 def test_magic_drc_pass(gds_empty: str):
     precheck.magic_drc(gds_empty, "TEST_empty")
 
@@ -101,3 +115,12 @@ def test_klayout_checks_pass(gds_empty: str):
 def test_klayout_checks_fail(gds_fail_metal5_poly: str):
     with pytest.raises(precheck.PrecheckFailure):
         precheck.klayout_checks(gds_fail_metal5_poly)
+
+
+def test_klayout_zero_area_drc_pass(gds_empty: str):
+    precheck.klayout_zero_area(gds_empty)
+
+
+def test_klayout_zero_area_drc_fail(gds_zero_area: str):
+    with pytest.raises(precheck.PrecheckFailure):
+        precheck.klayout_zero_area(gds_zero_area)