From 398047645591e138a6fd1ce8e9dfd069e1016ffe Mon Sep 17 00:00:00 2001
From: Matthias Koefferlein <matthias@klayout.de>
Date: Tue, 4 Jul 2023 00:19:55 +0200
Subject: [PATCH] Trying to improve deep mode performance by avoiding multiple
 cell mapping operations due to partial hierarchy transfer. On the cost side,
 the hierarchy is always duplicated.

---
 src/db/db/dbHierarchyBuilder.h        | 1 +
 src/db/db/dbRecursiveShapeIterator.cc | 6 +++++-
 src/db/db/dbRecursiveShapeIterator.h  | 5 +++++
 src/lvs/unit_tests/lvsTests.cc        | 2 +-
 4 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/db/db/dbHierarchyBuilder.h b/src/db/db/dbHierarchyBuilder.h
index 4cd47efce..3847e57a6 100644
--- a/src/db/db/dbHierarchyBuilder.h
+++ b/src/db/db/dbHierarchyBuilder.h
@@ -295,6 +295,7 @@ public:
    */
   void set_shape_receiver (HierarchyBuilderShapeReceiver *pipe);
 
+  virtual bool wants_all_cells () const { return true; }
   virtual void begin (const RecursiveShapeIterator *iter);
   virtual void end (const RecursiveShapeIterator *iter);
   virtual void enter_cell (const RecursiveShapeIterator *iter, const db::Cell *cell, const db::Box &region, const box_tree_type *complex_region);
diff --git a/src/db/db/dbRecursiveShapeIterator.cc b/src/db/db/dbRecursiveShapeIterator.cc
index af551b6e2..979ab6d78 100644
--- a/src/db/db/dbRecursiveShapeIterator.cc
+++ b/src/db/db/dbRecursiveShapeIterator.cc
@@ -693,7 +693,11 @@ RecursiveShapeIterator::next_shape (RecursiveShapeReceiver *receiver) const
 
         //  determine whether the cell is empty with respect to the layers specified
         bool is_empty = false;
-        if (! m_has_layers) {
+        if (receiver && receiver->wants_all_cells ()) {
+
+          //  don't skip empty cells in that case
+
+        } else if (! m_has_layers) {
 
           is_empty = mp_layout->cell (m_inst->cell_index ()).bbox (m_layer).empty ();
 
diff --git a/src/db/db/dbRecursiveShapeIterator.h b/src/db/db/dbRecursiveShapeIterator.h
index 99ffeb1fc..281a7ce82 100644
--- a/src/db/db/dbRecursiveShapeIterator.h
+++ b/src/db/db/dbRecursiveShapeIterator.h
@@ -913,6 +913,11 @@ public:
    */
   virtual ~RecursiveShapeReceiver () { }
 
+  /**
+   *  @brief Returns true, if the receivers wants the full hierarchy and not just non-empty cells
+   */
+  virtual bool wants_all_cells () const { return false; }
+
   /**
    *  @brief Called once when the iterator begins pushing
    */
diff --git a/src/lvs/unit_tests/lvsTests.cc b/src/lvs/unit_tests/lvsTests.cc
index 18c0810bf..5836b7578 100644
--- a/src/lvs/unit_tests/lvsTests.cc
+++ b/src/lvs/unit_tests/lvsTests.cc
@@ -142,7 +142,7 @@ TEST(16_private)
 TEST(17_private)
 {
   test_is_long_runner ();
-  run_test (_this, "test_17.lylvs", "test_17b.cir.gz", "test_17.gds.gz", true, "test_17b_4.lvsdb");
+  run_test (_this, "test_17.lylvs", "test_17b.cir.gz", "test_17.gds.gz", true, "test_17b_5.lvsdb");
 }
 
 TEST(18_private)