fixed log tests that were failing because gas calculations were resulting in U256 to overflow

src/ethereum/frontier/vm/gas.py

@@ -15,6 +15,7 @@
 from ethereum.frontier.eth_types import Address
 from ethereum.frontier.state import State, account_exists
 from ethereum.utils.numeric import ceil32
+from ethereum.utils.safe_arithmetic import u256_safe_add
 
 from .error import OutOfGasError
 
@@ -96,7 +97,10 @@ def calculate_memory_gas_cost(size_in_bytes: Uint) -> U256:
     linear_cost = size_in_words * GAS_MEMORY
     quadratic_cost = size_in_words ** 2 // 512
     total_gas_cost = linear_cost + quadratic_cost
-    return U256(total_gas_cost)
+    try:
+        return U256(total_gas_cost)
+    except ValueError:
+        raise OutOfGasError
 
 
 def calculate_gas_extend_memory(
@@ -159,7 +163,13 @@ def calculate_call_gas_cost(
     _account_exists = account_exists(state, to)
     create_gas_cost = U256(0) if _account_exists else GAS_NEW_ACCOUNT
     transfer_gas_cost = U256(0) if value == 0 else GAS_CALL_VALUE
-    return GAS_CALL + gas + create_gas_cost + transfer_gas_cost
+    return u256_safe_add(
+        GAS_CALL,
+        gas,
+        create_gas_cost,
+        transfer_gas_cost,
+        exception_type=OutOfGasError,
+    )
 
 
 def calculate_message_call_gas_stipend(value: U256) -> U256:

src/ethereum/frontier/vm/instructions/log.py

@@ -13,7 +13,9 @@
 """
 from functools import partial
 
-from ethereum.base_types import Uint
+from ethereum.base_types import U256, Uint
+from ethereum.frontier.vm.error import OutOfGasError
+from ethereum.utils.safe_arithmetic import u256_safe_add, u256_safe_multiply
 
 from ...eth_types import Log
 from .. import Evm
@@ -28,7 +30,7 @@
 from ..stack import pop
 
 
-def log_n(evm: Evm, num_topics: int) -> None:
+def log_n(evm: Evm, num_topics: U256) -> None:
     """
     Appends a log entry, having `num_topics` topics, to the evm logs.
 
@@ -52,11 +54,21 @@ def log_n(evm: Evm, num_topics: int) -> None:
     memory_start_index = Uint(pop(evm.stack))
     size = pop(evm.stack)
 
-    gas_cost = (
-        GAS_LOG
-        + (GAS_LOG_DATA * size)
-        + (GAS_LOG_TOPIC * num_topics)
-        + calculate_gas_extend_memory(evm.memory, memory_start_index, size)
+    gas_cost_log_data = u256_safe_multiply(
+        GAS_LOG_DATA, size, exception_type=OutOfGasError
+    )
+    gas_cost_log_topic = u256_safe_multiply(
+        GAS_LOG_TOPIC, num_topics, exception_type=OutOfGasError
+    )
+    gas_cost_memory_extend = calculate_gas_extend_memory(
+        evm.memory, memory_start_index, size
+    )
+    gas_cost = u256_safe_add(
+        GAS_LOG,
+        gas_cost_log_data,
+        gas_cost_log_topic,
+        gas_cost_memory_extend,
+        exception_type=OutOfGasError,
     )
     evm.gas_left = subtract_gas(evm.gas_left, gas_cost)
 

src/ethereum/utils/safe_arithmetic.py

@@ -0,0 +1,93 @@
+"""
+Safe Arithmetic for U256 Integer Type
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+..contents:: Table of Contents
+    :backlinks: none
+    :local:
+
+Introduction
+------------
+
+Safe arithmetic utility functions for U256 integer type.
+"""
+from typing import Optional, Type
+
+from ethereum.base_types import U256
+
+
+def u256_safe_add(
+    *numbers: U256, exception_type: Optional[Type[BaseException]] = None
+) -> U256:
+    """
+    Adds together the given sequence of numbers. If the total sum of the
+    numbers exceeds `U256.MAX_VALUE` then an exception is raised.
+    If `exception_type` = None then the exception raised defaults to the one
+    raised by `U256` when `U256.value > U256.MAX_VALUE`
+    else `exception_type` is raised.
+
+    Parameters
+    ----------
+    numbers :
+        The sequence of numbers that need to be added together.
+
+    exception_type:
+        The exception that needs to be raised if the sum of the `numbers`
+        exceeds `U256.MAX_VALUE`.
+
+    Returns
+    -------
+    result : `ethereum.base_types.U256`
+        The sum of the given sequence of numbers if the total is less than
+        `U256.MAX_VALUE` else an exception is raised.
+        If `exception_type` = None then the exception raised defaults to the
+        one raised by `U256` when `U256.value > U256.MAX_VALUE`
+        else `exception_type` is raised.
+    """
+    try:
+        return U256(sum(numbers))
+    except ValueError as e:
+        if exception_type:
+            raise exception_type from e
+        else:
+            raise e
+
+
+def u256_safe_multiply(
+    *numbers: U256, exception_type: Optional[Type[BaseException]] = None
+) -> U256:
+    """
+    Multiplies together the given sequence of numbers. If the net product of
+    the numbers exceeds `U256.MAX_VALUE` then an exception is raised.
+    If `exception_type` = None then the exception raised defaults to the one
+    raised by `U256` when `U256.value > U256.MAX_VALUE` else
+    `exception_type` is raised.
+
+    Parameters
+    ----------
+    numbers :
+        The sequence of numbers that need to be multiplies together.
+
+    exception_type:
+        The exception that needs to be raised if the sum of the `numbers`
+        exceeds `U256.MAX_VALUE`.
+
+    Returns
+    -------
+    result : `ethereum.base_types.U256`
+        The multiplication product of the given sequence of numbers if the
+        net product  is less than `U256.MAX_VALUE` else an exception is raised.
+        If `exception_type` = None then the exception raised defaults to the
+        one raised by `U256` when `U256.value > U256.MAX_VALUE`
+        else `exception_type` is raised.
+    """
+    result = numbers[0]
+    try:
+        for number in numbers[1:]:
+            result *= number
+        return result
+    except ValueError as e:
+        if exception_type:
+            raise exception_type from e
+        else:
+            raise e

tests/frontier/test_state_transition.py

@@ -93,19 +93,18 @@ def test_transaction_init(test_file: str) -> None:
         "log4_nonEmptyMem_d0g0v0.json",
         "log4_nonEmptyMem_logMemSize1_d0g0v0.json",
         "log4_nonEmptyMem_logMemSize1_logMemStart31_d0g0v0.json",
-        # FIXME: The tests below are failing because gas calculation is causing
-        #  U256 to overflow. These tests are supposed to fail with OOG exception
-        #  "log0_logMemStartTooHigh_d0g0v0.json",
-        #  "log0_logMemsizeTooHigh_d0g0v0.json",
-        #  "log1_logMemStartTooHigh_d0g0v0.json",
-        #  "log1_logMemsizeTooHigh_d0g0v0.json",
-        #  "log2_logMemStartTooHigh_d0g0v0.json",
-        #  "log2_logMemsizeTooHigh_d0g0v0.json",
-        #  "log3_logMemStartTooHigh_d0g0v0.json",
-        #  "log3_logMemsizeTooHigh_d0g0v0.json",
-        #  "log4_logMemStartTooHigh_d0g0v0.json",
-        #  "log4_logMemsizeTooHigh_d0g0v0.json",
-        #  "logInOOG_Call_d0g0v0.json",
+        "log0_logMemStartTooHigh_d0g0v0.json",
+        "log0_logMemsizeTooHigh_d0g0v0.json",
+        "log1_logMemStartTooHigh_d0g0v0.json",
+        "log1_logMemsizeTooHigh_d0g0v0.json",
+        "log2_logMemStartTooHigh_d0g0v0.json",
+        "log2_logMemsizeTooHigh_d0g0v0.json",
+        "log3_logMemStartTooHigh_d0g0v0.json",
+        "log3_logMemsizeTooHigh_d0g0v0.json",
+        "log4_logMemStartTooHigh_d0g0v0.json",
+        "log4_logMemsizeTooHigh_d0g0v0.json",
+        # FIXME: The receipt root doesn't match for the test below
+        # "logInOOG_Call_d0g0v0.json",
     ],
 )
 def test_log_operations(test_file: str) -> None: