From 3513966078b5e9bf926aa1f3feb0959a6639a1f8 Mon Sep 17 00:00:00 2001
From: tangxifan <tangxifan@gmail.com>
Date: Thu, 4 Feb 2021 17:30:49 -0700
Subject: [PATCH] [Tool] Borrow a quick fix from the VPR pull request
 https://github.com/verilog-to-routing/vtr-verilog-to-routing/pull/1656/files

---
 vpr/src/pack/cluster.cpp | 62 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/vpr/src/pack/cluster.cpp b/vpr/src/pack/cluster.cpp
index 51de31f7e..706e82e74 100644
--- a/vpr/src/pack/cluster.cpp
+++ b/vpr/src/pack/cluster.cpp
@@ -1185,6 +1185,64 @@ static void alloc_and_load_pb_stats(t_pb* pb, const int feasible_block_array_siz
 }
 /*****************************************/
 
+/**
+ *  * Cleans up a pb after unsuccessful molecule packing
+ *   */
+static bool cleanup_pb(t_pb* pb) {
+    bool can_free = true;
+
+    /* Recursively check if there are any children with already assigned atoms */
+    if (pb->child_pbs != nullptr) {
+        const t_mode* mode = &pb->pb_graph_node->pb_type->modes[pb->mode];
+        VTR_ASSERT(mode != nullptr);
+
+        /* Check each mode */
+        for (int i = 0; i < mode->num_pb_type_children; ++i) {
+            /* Check each child */
+            if (pb->child_pbs[i] != nullptr) {
+                for (int j = 0; j < mode->pb_type_children[i].num_pb; ++j) {
+                    t_pb* pb_child = &pb->child_pbs[i][j];
+                    t_pb_type* pb_type = pb_child->pb_graph_node->pb_type;
+
+                    /* Primitive, check occupancy */
+                    if (pb_type->num_modes == 0) {
+                        if (pb_child->name != nullptr) {
+                            can_free = false;
+                        }
+                    }
+
+                    /* Non-primitive, recurse */
+                    else {
+                        if (!cleanup_pb(pb_child)) {
+                            can_free = false;
+                        }
+                    }
+                }
+            }
+        }
+
+        /* Free if can */
+        if (can_free) {
+            for (int i = 0; i < mode->num_pb_type_children; ++i) {
+                if (pb->child_pbs[i] != nullptr) {
+                    delete[] pb->child_pbs[i];
+                }
+            }
+
+            delete[] pb->child_pbs;
+            pb->child_pbs = nullptr;
+            pb->mode = 0;
+
+            if (pb->name) {
+                free(pb->name);
+                pb->name = nullptr;
+            }
+        }
+    }
+
+    return can_free;
+}
+
 /**
  * Try pack molecule into current cluster
  */
@@ -1364,6 +1422,10 @@ static enum e_block_pack_status try_pack_molecule(t_cluster_placement_stats* clu
                         revert_place_atom_block(molecule->atom_block_ids[i], router_data, atom_molecules);
                     }
                 }
+
+                /* Placement failed, clean the pb */
+                cleanup_pb(pb);
+
             } else {
                 VTR_LOGV(verbosity > 3, "\t\tPASSED pack molecule\n");
             }