Cache randomization calls

doc/source/constraints.rst

@@ -81,7 +81,7 @@ condition without knowing the details of what that condition is.
 
         my_i = my_cls()
 
-        with my_i.randomize()
+        my_i.randomize()
 
         with my_i.randomize_with() as it:
             it.a_small()

doc/source/features.rst

@@ -5,6 +5,7 @@ PyVSC Features
 
 Constraint Features
 
+The short-circuit operators, ``and`` and ``or``, in Python can cannot be overloaded by PyVSC and shouldn't be used in constraints.
 
 =========================  ======  =============  ===  ===========
 Feature                    PyVSC   SystemVerilog  PSS  Description

src/vsc/model/field_composite_model.py

@@ -142,13 +142,15 @@ def pre_randomize(self):
 
     def post_randomize(self):
         """Called during the randomization process to propagate `post_randomize` event"""
-
+
+        # If randomize is called inside post_randomize with caching enabled, which
+        # value should be written? Prioritize writing current field values before re-randomizing.
+        for f in self.field_l:
+            f.post_randomize()
+
         # Perform a phase callback if available
         if self.is_used_rand and self.rand_if is not None:
             self.rand_if.do_post_randomize()
-
-        for f in self.field_l:
-            f.post_randomize()
 
     def accept(self, v):
         v.visit_composite_field(self)

src/vsc/model/field_scalar_model.py

@@ -19,6 +19,7 @@
 #
 # @author: ballance
 
+from copy import deepcopy
 
 from vsc.model.field_model import FieldModel
 from vsc.model.rand_gen_data import RandGenData
@@ -44,7 +45,24 @@ def __init__(self,
         self.rand_if = rand_if
         self.var = None
         self.val = ValueScalar(0)
-
+
+    def __deepcopy__(self, memo):
+        cls = self.__class__
+        result = cls.__new__(cls)
+        memo[id(self)] = result
+        for k, v in self.__dict__.items():
+            if k not in ['var']:
+                setattr(result, k, deepcopy(v, memo))
+
+        # TODO This is a workaround for the deepcopy in do_randomize somewhere getting
+        #      access to Boolector objects, which in turn can't be deepcopied.
+        result.var = None
+
+        # NOTE Deepcopy everything except val, keep it as reference so top level can get value
+        result.val = self.val
+
+        return result
+
     def set_used_rand(self, is_rand, level=0):
         # Field is considered rand when
         # - It is a root field, on which 'randomize' is called

src/vsc/model/rand_state.py

@@ -9,11 +9,13 @@ class RandState(object):
 
     def __init__(self, seed):
         self.rng = random.Random()
-        self.rng.seed(f"{seed}")
+        self.init_seed = f"{seed}"
+        self.rng.seed(self.init_seed)
 
     def clone(self) -> 'RandState':
         randState = RandState("")
         randState.rng.setstate(self.rng.getstate())
+        randState.init_seed = self.init_seed
         return randState 
 
     def rand_u(self):