spec: remove unused code, fix state_sim speed

beacon_chain/beacon_node.nim

@@ -156,7 +156,9 @@ proc makeAttestation(node: BeaconNode,
   if get_current_epoch(node.beaconState) == node.beaconState.justified_epoch:
     return
 
-  let justifiedBlockRoot = get_block_root(node.beaconState, get_epoch_start_slot(node.beaconState.justified_epoch))
+  let justifiedBlockRoot =
+    get_block_root(node.beaconState,
+      get_epoch_start_slot(node.beaconState.justified_epoch))
 
   var attestationData = AttestationData(
     slot: slot,
@@ -294,10 +296,6 @@ proc scheduleEpochActions(node: BeaconNode, epoch: uint64) =
       # missing blocks if necessary
       scheduleBlockProposal(node, slot, validator)
 
-    # Schedule attestations
-    let
-      committeesIdx = get_shard_committees_index(nextState, slot)
-
     #for shard in node.beaconState.shard_committees_at_slots[committees_idx]:
     for crosslink_committee in get_crosslink_committees_at_slot(
         node.beaconState, committees_idx):

beacon_chain/spec/helpers.nim

@@ -31,9 +31,6 @@ func verify_bitfield*(bitfield: openarray[byte], committee_size: int): bool =
 
   true
 
-func mod_get[T](arr: openarray[T], pos: Natural): T =
-  arr[pos mod arr.len]
-
 func shuffle*[T](values: seq[T], seed: Eth2Digest): seq[T] =
   ## Returns the shuffled ``values`` with seed as entropy.
   ## TODO: this calls out for tests, but I odn't particularly trust spec
@@ -114,15 +111,6 @@ func repeat_hash*(v: Eth2Digest, n: SomeInteger): Eth2Digest =
     result = eth2hash(result.data)
     dec n
 
-func get_shard_committees_index*(state: BeaconState, slot: uint64): uint64 =
-  # TODO temporary adapter; remove when all users gone
-  ## Warning: as it stands, this helper only works during state updates _after_
-  ## state.slot has been incremented but before shard_committees_at_slots has
-  ## been updated!
-  # TODO spec unsigned-unsafe here
-  doAssert slot + (state.slot mod EPOCH_LENGTH) + EPOCH_LENGTH > state.slot
-  slot + (state.slot mod EPOCH_LENGTH) + EPOCH_LENGTH - state.slot
-
 func integer_squareroot*(n: SomeInteger): SomeInteger =
   ## The largest integer ``x`` such that ``x**2`` is less than ``n``.
   var

beacon_chain/spec/validator.nim

@@ -66,13 +66,6 @@ func get_previous_epoch_committee_count(state: BeaconState): uint64 =
   )
   get_epoch_committee_count(len(previous_active_validators))
 
-func get_current_epoch_committee_count_per_slot(state: BeaconState): uint64 =
-  let current_active_validators = get_active_validator_indices(
-    state.validator_registry,
-    state.current_calculation_epoch,
-  )
-  get_epoch_committee_count(len(current_active_validators))
-
 func get_crosslink_committees_at_slot*(state: BeaconState, slot: uint64):
     seq[CrosslinkCommittee] =
   ## Returns the list of ``(committee, shard)`` tuples for the ``slot``.
@@ -86,7 +79,7 @@ func get_crosslink_committees_at_slot*(state: BeaconState, slot: uint64):
   assert previous_epoch <= epoch
   assert epoch < next_epoch
 
-  func get_epoch_specific_params() : auto =
+  template get_epoch_specific_params(): auto =
     if epoch < current_epoch:
       let
         committees_per_epoch = get_previous_epoch_committee_count(state)
@@ -102,7 +95,8 @@ func get_crosslink_committees_at_slot*(state: BeaconState, slot: uint64):
         shuffling_start_shard = state.current_epoch_start_shard
       (committees_per_epoch, seed, shuffling_epoch, shuffling_start_shard)
 
-  let (committees_per_epoch, seed, shuffling_epoch, shuffling_start_shard) = get_epoch_specific_params()
+  let (committees_per_epoch, seed, shuffling_epoch, shuffling_start_shard) =
+    get_epoch_specific_params()
 
   let
     shuffling = get_shuffling(