pdn: grid: limit via-repair shape extension to ring/domain boundary

Shape::extendTo() had no awareness of the grid boundary, allowing
repairVias() to extend stripes through the padframe when a via landed
at the ring edge. Now the extended shape is accepted only if it stays
within getRingArea() (or getDomainBoundary() for ring-less grids).

Signed-off-by: Daniel Schultz <dnltz@aesc-silicon.de>

Author: dnltz

src/pdn/src/grid.cpp

@@ -313,6 +313,13 @@ bool Grid::repairVias(const Shape::ShapeTreeMap& global_shapes,
     return !shape->belongsTo(this);
   };
 
+  // Shapes must not be extended beyond the grid's allowed area: respect the
+  // ring boundary (if rings exist) or the domain boundary otherwise.  Without
+  // this guard, extendTo() can push stripes through the padframe when a via
+  // sits right at the ring/domain edge.
+  const odb::Rect allowed_area
+      = rings_.empty() ? getDomainBoundary() : getRingArea();
+
   std::map<Shape*, std::unique_ptr<Shape>> replace_shapes;
   for (const auto& via : vias_) {
     // ensure shapes belong to something
@@ -345,7 +352,7 @@ bool Grid::repairVias(const Shape::ShapeTreeMap& global_shapes,
                                   obstructions[extend_test->getLayer()],
                                   lower_shape.get(),
                                   obs_filter);
-      if (new_lower != nullptr) {
+      if (new_lower != nullptr && allowed_area.contains(new_lower->getRect())) {
         replace_shapes[lower_shape.get()] = std::move(new_lower);
       }
     }
@@ -361,7 +368,7 @@ bool Grid::repairVias(const Shape::ShapeTreeMap& global_shapes,
                                   obstructions[extend_test->getLayer()],
                                   upper_shape.get(),
                                   obs_filter);
-      if (new_upper != nullptr) {
+      if (new_upper != nullptr && allowed_area.contains(new_upper->getRect())) {
         replace_shapes[upper_shape.get()] = std::move(new_upper);
       }
     }