Implement difficulty calculation for homestead

evm/constants.py

@@ -109,6 +109,7 @@
 DIFFICULTY_MINIMUM = 131072
 
 FRONTIER_DIFFICULTY_ADJUSTMENT_CUTOFF = 13
+HOMESTEAD_DIFF_ADJUSTMENT_CUTOFF = 10
 
 BOMB_EXPONENTIAL_PERIOD = 100000
 BOMB_EXPONENTIAL_FREE_PERIODS = 2

evm/vm/flavors/homestead/__init__.py

@@ -12,6 +12,10 @@
 from .opcodes import HOMESTEAD_OPCODES
 from .blocks import HomesteadBlock
 from .validation import validate_homestead_transaction
+from .headers import (
+    create_homestead_header_from_parent,
+    configure_homestead_header,
+)
 
 
 def _apply_homestead_create_message(vm, message):
@@ -62,4 +66,6 @@ def _apply_homestead_create_message(vm, message):
     # method overrides
     validate_transaction=validate_homestead_transaction,
     apply_create_message=_apply_homestead_create_message,
+    create_header_from_parent=staticmethod(create_homestead_header_from_parent),
+    configure_header=configure_homestead_header,
 )

evm/vm/flavors/homestead/blocks.py

@@ -1,3 +1,9 @@
+from rlp.sedes import (
+    CountableList,
+)
+from evm.rlp.headers import (
+    BlockHeader,
+)
 from evm.vm.flavors.frontier.blocks import (
     FrontierBlock,
 )
@@ -8,3 +14,8 @@
 
 class HomesteadBlock(FrontierBlock):
     transaction_class = HomesteadTransaction
+    fields = [
+        ('header', BlockHeader),
+        ('transactions', CountableList(HomesteadTransaction)),
+        ('uncles', CountableList(BlockHeader))
+    ]

evm/vm/flavors/homestead/headers.py

@@ -0,0 +1,58 @@
+from evm.validation import (
+    validate_gt,
+)
+from evm.constants import (
+    DIFFICULTY_ADJUSTMENT_DENOMINATOR,
+    DIFFICULTY_MINIMUM,
+    BOMB_EXPONENTIAL_PERIOD,
+    BOMB_EXPONENTIAL_FREE_PERIODS,
+    HOMESTEAD_DIFF_ADJUSTMENT_CUTOFF,
+)
+
+from evm.vm.flavors.frontier.headers import (
+    configure_frontier_header,
+    create_frontier_header_from_parent,
+)
+
+
+def compute_homestead_difficulty(parent_header, timestamp):
+    """
+    Computes the difficulty for a homestead block based on the parent block.
+    """
+    parent_tstamp = parent_header.timestamp
+    validate_gt(timestamp, parent_tstamp)
+    offset = parent_header.difficulty // DIFFICULTY_ADJUSTMENT_DENOMINATOR
+    sign = max(
+        1 - (timestamp - parent_tstamp) // HOMESTEAD_DIFF_ADJUSTMENT_CUTOFF,
+        -99)
+    difficulty = int(max(
+        parent_header.difficulty + offset * sign,
+        min(parent_header.difficulty, DIFFICULTY_MINIMUM)))
+    num_bomb_periods = (
+        (parent_header.block_number + 1) // BOMB_EXPONENTIAL_PERIOD
+    ) - BOMB_EXPONENTIAL_FREE_PERIODS
+    if num_bomb_periods >= 0:
+        return max(difficulty + 2**num_bomb_periods, DIFFICULTY_MINIMUM)
+    else:
+        return difficulty
+
+
+def create_homestead_header_from_parent(parent_header, **header_params):
+    if 'difficulty' not in header_params:
+        timestamp = header_params.get('timestamp', parent_header.timestamp + 1)
+        header_params['difficulty'] = compute_homestead_difficulty(
+            parent_header,
+            timestamp,
+        )
+    return create_frontier_header_from_parent(parent_header, **header_params)
+
+
+def configure_homestead_header(vm, **header_params):
+    header = configure_frontier_header(vm, **header_params)
+    if 'timestamp' in header_params and header.block_number > 0:
+        parent_header = vm.block.get_parent_header()
+        header.difficulty = compute_homestead_difficulty(
+            parent_header,
+            header_params['timestamp'],
+        )
+    return header

tests/json-fixtures/test_blockchain.py

@@ -12,10 +12,12 @@
     keccak,
 )
 
+from evm import EVM
 from evm.exceptions import (
     ValidationError,
 )
 from evm.vm.flavors import (
+    HomesteadVM,
     MainnetEVM,
 )
 from evm.rlp.headers import (
@@ -49,8 +51,6 @@ def blockchain_fixture_skip_fn(fixture_path, fixture_name, fixture):
     return (
         ":".join([fixture_path, fixture_name]) in DISABLED_INDIVIDUAL_TESTS or
         fixture_path.startswith('TestNetwork') or  # TODO: enable
-        'Homestead' in fixture_path or  # TODO: enable
-        'Homestead' in fixture_name or  # TODO: enable
         'EIP150' in fixture_path or  # TODO: enable
         'EIP150' in fixture_name or  # TODO: enable
         'EIP158' in fixture_path or  # TODO: enable
@@ -59,16 +59,12 @@ def blockchain_fixture_skip_fn(fixture_path, fixture_name, fixture):
 
 
 SLOW_FIXTURE_NAMES = {
-    'GeneralStateTests/stAttackTest/ContractCreationSpam.json:ContractCreationSpam_d0g0v0_Frontier',
-    'GeneralStateTests/stBoundsTest/MLOAD_Bounds.json:MLOAD_Bounds_d0g0v0_Frontier',
-    'GeneralStateTests/stMemoryStressTest/CALLCODE_Bounds3.json:CALLCODE_Bounds3_d0g0v0_Frontier',
-    'GeneralStateTests/stMemoryStressTest/CALL_Bounds2.json:CALL_Bounds2_d0g0v0_Frontier',
-    'GeneralStateTests/stMemoryStressTest/CALL_Bounds2a.json:CALL_Bounds2a_d0g0v0_Frontier',
-    'GeneralStateTests/stCallCreateCallCodeTest/Call1024OOG.json:Call1024OOG_d0g0v0_Frontier',
-    'GeneralStateTests/stCallCreateCallCodeTest/Callcode1024OOG.json:Callcode1024OOG_d0g0v0_Frontier',
-    'GeneralStateTests/stCallCreateCallCodeTest/CallRecursiveBombPreCall.json:CallRecursiveBombPreCall_d0g0v0_Frontier',
     'bcForkStressTest.json:ForkStressTest',
     'bcWalletTest.json:walletReorganizeOwners',
+    'Homestead/bcExploitTest.json:DelegateCallSpam',
+    "Homestead/bcSuicideIssue.json:SuicideIssue",
+    "Homestead/bcWalletTest.json:walletReorganizeOwners",
+    "Homestead/bcShanghaiLove.json:Devcon2Attack",
 }
 
 
@@ -116,7 +112,14 @@ def test_blockchain_fixtures(fixture_name, fixture):
     #     assert rlp.encode(genesis_header) == fixture['genesisRLP']
 
     db = MemoryDB()
-    evm = MainnetEVM.from_genesis(
+
+    evm = MainnetEVM
+    if fixture_name.startswith('Homestead'):
+        evm = EVM.configure(
+            'HomesteadEVM',
+            vm_configuration=[(0, HomesteadVM)])
+
+    evm = evm.from_genesis(
         db,
         genesis_params=genesis_params,
         genesis_state=fixture['pre'],