Rework FPGA interchange site router.

The new site router should be robust to most situations, and isn't
significantly slower with the use of caching.

Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/fpga_interchange/archdefs.h b/fpga_interchange/archdefs.h
index d20c5ea4..8364520d 100644
--- a/fpga_interchange/archdefs.h
+++ b/fpga_interchange/archdefs.h
@@ -98,11 +98,14 @@ struct BelBucketId
     bool operator<(const BelBucketId &other) const { return name < other.name; }
 };
 
+struct SiteExpansionLoop;
+
 struct ArchNetInfo
 {
-};
+    virtual ~ArchNetInfo();
 
-struct NetInfo;
+    SiteExpansionLoop *loop = nullptr;
+};
 
 struct ArchCellInfo
 {