python: Convert empty BelId to None

Signed-off-by: David Shah <davey1576@gmail.com>

generic/arch_pybindings.cc

@@ -20,8 +20,8 @@
 
 #ifndef NO_PYTHON
 
-#include "pybindings.h"
 #include "nextpnr.h"
+#include "pybindings.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 

generic/arch_pybindings.h

@@ -21,8 +21,8 @@
 #define ARCH_PYBINDINGS_H
 #ifndef NO_PYTHON
 
-#include "pybindings.h"
 #include "nextpnr.h"
+#include "pybindings.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 

ice40/arch_pybindings.cc

@@ -20,9 +20,9 @@
 
 #ifndef NO_PYTHON
 
-#include "pybindings.h"
 #include "arch_pybindings.h"
 #include "nextpnr.h"
+#include "pybindings.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 

ice40/arch_pybindings.h

@@ -21,8 +21,9 @@
 #define ARCH_PYBINDINGS_H
 #ifndef NO_PYTHON
 
-#include "pybindings.h"
 #include "nextpnr.h"
+#include "pybindings.h"
+#include "pywrappers.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 
@@ -32,7 +33,12 @@ template <> struct string_converter<BelId>
 {
     BelId from_str(Context *ctx, std::string name) { return ctx->getBelByName(ctx->id(name)); }
 
-    std::string to_str(Context *ctx, BelId id) { return ctx->getBelName(id).str(ctx); }
+    std::string to_str(Context *ctx, BelId id)
+    {
+        if (id == BelId())
+            throw bad_wrap();
+        return ctx->getBelName(id).str(ctx);
+    }
 };
 
 template <> struct string_converter<BelType>

python/dump_design.py

@@ -20,6 +20,6 @@ for cell, cinfo in sorted(ctx.cells, key=lambda x: x.first):
                 val = "{}'b{}".format(len(val), val)
             print("\t\t{}: {}".format(param, val))
 
-    if cinfo.bel.index != -1:
+    if cinfo.bel is not None:
         print("\tBel: {}".format(cinfo.bel))
     print()