add some comments, minor nits

vyper/venom/analysis.py

@@ -20,9 +20,8 @@ def calculate_cfg(ctx: IRFunction) -> None:
         bb.out_vars = OrderedSet()
 
     # TODO: This is a hack to support the old IR format
-    # where deploy is an instruction. Going directly to the new IR we should have just
-    # one entry for the contructor and one for the runtime core. These will be propertly
-    # linked in the CFG, and the deploy instruction will be removed completely.
+    # where deploy is an instruction. Going directly to the new IR we should
+    # have two entry points, one for the initcode and one for the runtime code.
     deploy_bb = None
     after_deploy_bb = None
     for i, bb in enumerate(ctx.basic_blocks):
@@ -31,33 +30,32 @@ def calculate_cfg(ctx: IRFunction) -> None:
             after_deploy_bb = ctx.basic_blocks[i + 1]
             break
 
-    if deploy_bb:
+    if deploy_bb is not None:
         assert after_deploy_bb is not None, "No block after deploy block"
         entry_block = after_deploy_bb
-        has_constructor = True if ctx.basic_blocks[0].instructions[0].opcode != "deploy" else False
+        has_constructor = ctx.basic_blocks[0].instructions[0].opcode != "deploy"
         if has_constructor:
             deploy_bb.add_cfg_in(ctx.basic_blocks[0])
             entry_block.add_cfg_in(deploy_bb)
     else:
         entry_block = ctx.basic_blocks[0]
 
     # TODO: Special case for the jump table of selector buckets and fallback.
-    # It will be generalized when the dispacher code is directly generated in Venom.
-    # The when directly generating the dispatcher code from the AST we should be emitting
-    # a dynamic jmp instruction with all the posible targets (this in EOF this will be also
-    # a jump via jump table). This will remove the need for this special case, and will result
-    # in cleaner code for normalization just according to CFG, without the need to examine
-    # the block termination instructions.
+    # It will be generalized when the dispacher code is directly generated in
+    # Venom. The when directly generating the dispatcher code from the AST we
+    # should be emitting a dynamic jmp instruction with all the posible targets
+    # (this in EOF this will be also a jump via jump table). This will remove
+    # the need for this special case, and will result in cleaner code for
+    # normalization just according to CFG, without the need to examine the
+    # block termination instructions.
     for bb in ctx.basic_blocks:
         if "selector_bucket_" in bb.label.value or bb.label.value == "fallback":
             bb.add_cfg_in(entry_block)
 
     for bb in ctx.basic_blocks:
         assert len(bb.instructions) > 0, "Basic block should not be empty"
         last_inst = bb.instructions[-1]
-        assert last_inst.opcode in BB_TERMINATORS, "Last instruction should be a terminator" + str(
-            bb
-        )
+        assert last_inst.opcode in BB_TERMINATORS, f"Last instruction should be a terminator {bb}"
 
         for inst in bb.instructions:
             if inst.opcode in CFG_ALTERING_OPS:

vyper/venom/passes/normalization.py

@@ -50,6 +50,8 @@ def _split_for_dynamic_branch(self, bb: IRBasicBlock, in_bb: IRBasicBlock) -> No
         split_bb = self._insert_split_basicblock(bb, in_bb)
 
         # Update any affected labels in the data segment
+        # TODO: this DESTROYS the cfg! refactor so the translation of the
+        # selector table produces indirect jumps properly.
         for inst in self.ctx.data_segment:
             if inst.opcode == "db" and inst.operands[0] == bb.label:
                 inst.operands[0] = split_bb.label
@@ -63,6 +65,9 @@ def _insert_split_basicblock(self, bb: IRBasicBlock, in_bb: IRBasicBlock) -> IRB
         self.ctx.append_basic_block(split_bb)
 
         # Rewire the CFG
+        # TODO: this is cursed code, it is necessary instead of just running
+        # calculate_cfg() because split_for_dynamic_branch destroys the CFG!
+        # ideally, remove this rewiring and just re-run calculate_cfg().
         split_bb.add_cfg_in(in_bb)
         split_bb.add_cfg_out(bb)
         in_bb.remove_cfg_out(bb)