Fix memory corruption due to the deletion of unused spare buffers.

* In cumulus/plugins.block.Block.{place,doPnr}(), reorder the
    feed insertion and spare buffer deletion call. Formerly, we
    were :
      1. Creating spare buffersa (Python).
      2. Placing (C++)
      3. Adding feeds (EtesianEngine::toHurricane() call) (C++).
      4. Removing unused spare buffers (Python).
   So, step 4 was *not* informing the C++ placement data-structure
   created at step 3 of the change. Resulting in occurrences using
   deleted Entities (Instance).
     Now we swap step 3. and 4. so toHurricane() is called *after*
   any Python managed change is done.
     Ideally, what we should implement is a way for Python to inform
   the C++ data-structure. No real problem here, but time...

cumulus/src/plugins/alpha/block/block.py

@@ -580,7 +580,6 @@ class Block ( object ):
         self.etesian.getCell().flattenNets( None, Cell.Flags_NoClockFlatten )
         if self.conf.useHFNS: self.etesian.doHFNS()
         self.etesian.place()
-        self.etesian.flattenPower()
         Breakpoint.stop( 100, 'Placement done.' )
         self.etesian.clearColoquinte()
 
@@ -744,8 +743,10 @@ class Block ( object ):
            #if self.conf.useHFNS: self.findHfnTrees()
             break
         if self.conf.useClockTree: self.splitClocks()
-        if self.conf.isCoreBlock:  self.doConnectCore()
         self.spares.removeUnusedBuffers()
+        self.etesian.toHurricane()
+        self.etesian.flattenPower()
+        if self.conf.isCoreBlock: self.doConnectCore()
         status = self.route()
         if not self.conf.isCoreBlock:
             self.addBlockages()

cumulus/src/plugins/alpha/block/spares.py

@@ -774,7 +774,9 @@ class QuadTree ( object ):
         netBuff = self.bOutputPlug.getNet()
         trace( 540, '\tBuffer: {}\n'.format(self.buffer) )
         trace( 540, '\tBuffer output: {}\n'.format(netBuff) )
-        if not self.plugs: return
+        if not self.plugs:
+            trace( 540, '-' )
+            return
         for plug in self.plugs:
             trace( 540, '\t| Leaf: {}\n'.format(plug) )
             trace( 540, '\t| netBuff: {}\n'.format(netBuff) )

cumulus/src/plugins/clocktree.py

@@ -87,10 +87,11 @@ def scriptMain ( **kw ):
         if editor: editor.refresh()
         etesian = Etesian.EtesianEngine.create( cell )
         etesian.place()
-        etesian.destroy()
         ht.connectLeaf()
        #ht.prune()
         ht.route()
+        etesian.toHurricane()
+        etesian.destroy()
         ht.save( cell )
     except Exception, e:
         helpers.io.catch( e )