[EIP-3978] Add LOGs gas refunds (ethereum#4691)

EIPS/eip-3978.md

@@ -8,12 +8,12 @@ status: Draft
 type: Standards Track
 category: Core
 created: 2021-09-16
-updated: 2021-12-30
+updated: 2022-01-17
 ---
 
 ## Abstract
 
- Since [EIP-3298](./eip-3298.md) gas refunds works for storage restores only inside the same transaction. For example [ERC-20](./eip-20.md) `approve` + `transferFrom` flow between 2 smart contracts according to [EIP-2200](./eip-2200.md) and [EIP-2929](./eip-2929.md) will cost nearly to `21600` gas with gas refund counter `20000`. But in case of reverting this subcall (containing both `approve` and `transferForm`) gas refund will be erased, while smart contract storage will remain unmodified. I think it should keep storage access costs, but still refund modification costs.
+ Since [EIP-3298](./eip-3298.md) gas refunds works for storage restores only inside the same transaction. For example [ERC-20](./eip-20.md) `approve` + `transferFrom` flow between 2 smart contracts according to [EIP-2200](./eip-2200.md) and [EIP-2929](./eip-2929.md) will cost nearly to `21600` gas with gas refund counter `20000`. But in case of reverting this subcall (containing both `approve` and `transferForm`) gas refund will be erased, while smart contract storage will remain unmodified. I think it should keep storage access costs, but still refund modification costs. Moreover it makes sense to have gas refund for reverted logs (events).
 
 ## Motivation
 
@@ -23,7 +23,7 @@ updated: 2021-12-30
 
 Let's consider all reverted SSTOREs as SLOADs (access) costs. This requires to remember (SSTORE - SLOAD) costs for each SSTORE inside every internal call excluding its subcalls and on revert let's update gas refund counter in the following manner:
 ```
-tx.gas_refund_counter = tx.gas_refund_counter - call.gas_refund_counter + call.sstores_sloads_diff_counter;
+tx.gas_refund_counter = tx.gas_refund_counter - call.gas_refund_counter + call.sstores_sloads_diff_counter + call.log_gas_counter;
 ```
 
 ## Rationale