Add SHL Opcode for Constantinople

Relates to #1104

Author: cburgdorf

eth/vm/forks/constantinople/opcodes.py

@@ -1,8 +1,35 @@
 import copy
+from cytoolz import (
+    merge
+)
 
+from eth import (
+    constants
+)
+from eth.vm import (
+    mnemonics,
+    opcode_values,
+)
 from eth.vm.forks.byzantium.opcodes import (
     BYZANTIUM_OPCODES
 )
+from eth.vm.logic import (
+    arithmetic
+)
+from eth.vm.opcode import (
+    as_opcode
+)
+
 
+UPDATED_OPCODES = {
+    opcode_values.SHL: as_opcode(
+        logic_fn=arithmetic.shl,
+        mnemonic=mnemonics.SHL,
+        gas_cost=constants.GAS_VERYLOW,
+    ),
+}
 
-CONSTANTINOPLE_OPCODES = copy.deepcopy(BYZANTIUM_OPCODES)
+CONSTANTINOPLE_OPCODES = merge(
+    copy.deepcopy(BYZANTIUM_OPCODES),
+    UPDATED_OPCODES,
+)

eth/vm/logic/arithmetic.py

@@ -177,3 +177,17 @@ def signextend(computation):
         result = value
 
     computation.stack_push(result)
+
+
+def shl(computation):
+    """
+    Bitwise left shift
+    """
+    shift_length, value = computation.stack_pop(num_items=2, type_hint=constants.UINT256)
+
+    if shift_length >= 256:
+        result = 0
+    else:
+        result = (value << shift_length) & constants.UINT_256_MAX
+
+    computation.stack_push(result)

eth/vm/mnemonics.py

@@ -13,6 +13,7 @@
 MULMOD = 'MULMOD'
 EXP = 'EXP'
 SIGNEXTEND = 'SIGNEXTEND'
+SHL = 'SHL'
 #
 # Comparisons
 #

eth/vm/opcode_values.py

@@ -29,6 +29,7 @@
 XOR = 0x18
 NOT = 0x19
 BYTE = 0x1a
+SHL = 0x1b
 
 
 #

tests/core/opcodes/test_opcodes.py

@@ -1,19 +1,23 @@
 import pytest
 
 from eth_utils import (
+    decode_hex,
+    encode_hex,
     to_canonical_address,
+    int_to_big_endian,
 )
 
 from eth import (
     constants
 )
+from eth.utils.padding import (
+    pad32
+)
 from eth.vm import (
     opcode_values
 )
-from eth.vm.forks.byzantium.opcodes import (
-    BYZANTIUM_OPCODES
-)
 from eth.vm.forks import (
+    ConstantinopleVM,
     ByzantiumVM,
     SpuriousDragonVM,
     TangerineWhistleVM,
@@ -98,3 +102,84 @@ def test_mul(vm_class, val1, val2, expected):
     assert result == expected
 
 
+@pytest.mark.parametrize(
+    # Testcases from https://github.com/ethereum/EIPs/blob/master/EIPS/eip-145.md#shl-shift-left
+    'vm_class, val1, val2, expected',
+    (
+        (
+            ConstantinopleVM,
+            '0x0000000000000000000000000000000000000000000000000000000000000001',
+            '0x00',
+            '0x0000000000000000000000000000000000000000000000000000000000000001',
+        ),
+        (
+            ConstantinopleVM,
+            '0x0000000000000000000000000000000000000000000000000000000000000001',
+            '0x01',
+            '0x0000000000000000000000000000000000000000000000000000000000000002',
+        ),
+        (
+            ConstantinopleVM,
+            '0x0000000000000000000000000000000000000000000000000000000000000001',
+            '0xff',
+            '0x8000000000000000000000000000000000000000000000000000000000000000',
+        ),
+        (
+            ConstantinopleVM,
+            '0x0000000000000000000000000000000000000000000000000000000000000001',
+            '0x0100',
+            '0x0000000000000000000000000000000000000000000000000000000000000000',
+        ),
+        (
+            ConstantinopleVM,
+            '0x0000000000000000000000000000000000000000000000000000000000000001',
+            '0x0101',
+            '0x0000000000000000000000000000000000000000000000000000000000000000',
+        ),
+        (
+            ConstantinopleVM,
+            '0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff',
+            '0x00',
+            '0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff',
+        ),
+        (
+            ConstantinopleVM,
+            '0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff',
+            '0x01',
+            '0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe',
+        ),
+        (
+            ConstantinopleVM,
+            '0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff',
+            '0xff',
+            '0x8000000000000000000000000000000000000000000000000000000000000000',
+        ),
+        (
+            ConstantinopleVM,
+            '0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff',
+            '0x0100',
+            '0x0000000000000000000000000000000000000000000000000000000000000000',
+        ),
+        (
+            ConstantinopleVM,
+            '0x0000000000000000000000000000000000000000000000000000000000000000',
+            '0x01',
+            '0x0000000000000000000000000000000000000000000000000000000000000000',
+        ),
+        (
+            ConstantinopleVM,
+            '0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff',
+            '0x01',
+            '0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe',
+        ),
+    )
+)
+def test_shl(vm_class, val1, val2, expected):
+    computation = prepare_computation(vm_class)
+    computation.stack_push(decode_hex(val1))
+    computation.stack_push(decode_hex(val2))
+    computation.opcodes[opcode_values.SHL](computation)
+
+    result = computation.stack_pop(type_hint=constants.UINT256)
+
+    assert encode_hex(pad32(int_to_big_endian(result))) == expected