From 76f7c620f6b0bf2f73bb3d152eac62fb6b409ab1 Mon Sep 17 00:00:00 2001
From: Matthias Koefferlein <matthias@klayout.de>
Date: Sat, 12 Jul 2025 13:58:47 +0200
Subject: [PATCH] [consider merging] Enabling Shapes-based
 RecursiveShapeIterators for MT-use

This fixes a crash when using DRC fill in tiled mode with multiple
threads.
---
 src/db/db/dbFillTool.cc               |  3 ++-
 src/db/db/dbRecursiveShapeIterator.cc |  6 ++++++
 src/db/db/dbShapes.cc                 | 10 ++++++++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/db/db/dbFillTool.cc b/src/db/db/dbFillTool.cc
index 50fa34cfe..d693be441 100644
--- a/src/db/db/dbFillTool.cc
+++ b/src/db/db/dbFillTool.cc
@@ -280,7 +280,8 @@ fill_polygon_impl (db::Cell *cell, const db::Polygon &fp0, db::cell_index_type f
 
             {
               //  In case we run this from a tiling processor we need to lock against multithread races
-              tl::MutexLocker locker (&db::TilingProcessor::output_lock ());
+              tl_assert (cell->layout () != 0);
+              tl::MutexLocker locker (&cell->layout ()->lock ());
               cell->insert (array);
             }
 
diff --git a/src/db/db/dbRecursiveShapeIterator.cc b/src/db/db/dbRecursiveShapeIterator.cc
index b3965f9ce..1f8758bd1 100644
--- a/src/db/db/dbRecursiveShapeIterator.cc
+++ b/src/db/db/dbRecursiveShapeIterator.cc
@@ -500,15 +500,21 @@ RecursiveShapeIterator::validate (RecursiveShapeReceiver *receiver) const
   }
 
   if (mp_shapes) {
+
     //  Ensures the trees are built properly - this is important in MT contexts (i.e. TilingProcessor)
     //  TODO: get rid of that const cast
     (const_cast <db::Shapes *> (mp_shapes))->update ();
+
     start_shapes ();
+
   } else if (mp_layout && (! m_has_layers || m_current_layer < m_layers.size ())) {
+
     //  Ensures the trees are built properly - this is important in MT contexts (i.e. TilingProcessor)
     mp_layout->update ();
+
     new_cell (receiver);
     next_shape (receiver);
+
   }
 
   if (mp_layout && ! at_end ()) {
diff --git a/src/db/db/dbShapes.cc b/src/db/db/dbShapes.cc
index 2c5e90f46..5774973b9 100644
--- a/src/db/db/dbShapes.cc
+++ b/src/db/db/dbShapes.cc
@@ -1127,10 +1127,20 @@ void Shapes::reset_bbox_dirty ()
 
 void Shapes::update ()
 {
+  std::unique_ptr<tl::MutexLocker> locker;
+
+  //  If not in a layout context, we should lock here against multiple calls from different threads.
+  //  In a layout context, the Layout object will do that for us.
+  if (layout () == 0) {
+    static tl::Mutex lock;
+    locker.reset (new tl::MutexLocker (&lock));
+  }
+
   for (tl::vector<LayerBase *>::const_iterator l = m_layers.begin (); l != m_layers.end (); ++l) {
     (*l)->sort ();
     (*l)->update_bbox ();
   }
+
   set_dirty (false);
 }