From f7c9cc256731a198443c914810d99bfcb7b2b835 Mon Sep 17 00:00:00 2001
From: Green <40367733+greenlucid@users.noreply.github.com>
Date: Wed, 20 Apr 2022 16:51:25 +0200
Subject: [PATCH] core: implement EIP 5022

---
 core/vm/eips.go           |  7 +++++++
 core/vm/gas_table.go      | 43 +++++++++++++++++++++++++++++++++++++++
 params/protocol_params.go |  1 +
 3 files changed, 51 insertions(+)

diff --git a/core/vm/eips.go b/core/vm/eips.go
index 4070a2db5342..de52a49506ef 100644
--- a/core/vm/eips.go
+++ b/core/vm/eips.go
@@ -25,6 +25,7 @@ import (
 )
 
 var activators = map[int]func(*JumpTable){
+	5022: enable5022,
 	3529: enable3529,
 	3198: enable3198,
 	2929: enable2929,
@@ -109,6 +110,12 @@ func enable2200(jt *JumpTable) {
 	jt[SSTORE].dynamicGas = gasSStoreEIP2200
 }
 
+// same as 2200, but different sstore zero -> non-zero pricing
+func enable5022(jt *JumpTable) {
+	jt[SLOAD].constantGas = params.SloadGasEIP2200
+	jt[SSTORE].dynamicGas = gasSStoreEIP5022
+}
+
 // enable2929 enables "EIP-2929: Gas cost increases for state access opcodes"
 // https://eips.ethereum.org/EIPS/eip-2929
 func enable2929(jt *JumpTable) {
diff --git a/core/vm/gas_table.go b/core/vm/gas_table.go
index 4c2cb3e5cf79..2cd5c63475ec 100644
--- a/core/vm/gas_table.go
+++ b/core/vm/gas_table.go
@@ -217,6 +217,49 @@ func gasSStoreEIP2200(evm *EVM, contract *Contract, stack *Stack, mem *Memory, m
 	return params.SloadGasEIP2200, nil // dirty update (2.2)
 }
 
+// Flow is the same as EIP2200, but different zero -> non-zero pricing
+func gasSStoreEIP5022(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	// If we fail the minimum gas availability invariant, fail (0)
+	if contract.Gas <= params.SstoreSentryGasEIP2200 {
+		return 0, errors.New("not enough gas for reentrancy sentry")
+	}
+	// Gas sentry honoured, do the actual gas calculation based on the stored value
+	var (
+		y, x    = stack.Back(1), stack.Back(0)
+		current = evm.StateDB.GetState(contract.Address(), x.Bytes32())
+	)
+	value := common.Hash(y.Bytes32())
+
+	if current == value { // noop (1)
+		return params.SloadGasEIP2200, nil
+	}
+	original := evm.StateDB.GetCommittedState(contract.Address(), x.Bytes32())
+	if original == current {
+		if original == (common.Hash{}) { // create slot (2.1.1)
+			return params.SstoreSetGasEIP5022, nil
+		}
+		if value == (common.Hash{}) { // delete slot (2.1.2b)
+			evm.StateDB.AddRefund(params.SstoreClearsScheduleRefundEIP2200)
+		}
+		return params.SstoreResetGasEIP2200, nil // write existing slot (2.1.2)
+	}
+	if original != (common.Hash{}) {
+		if current == (common.Hash{}) { // recreate slot (2.2.1.1)
+			evm.StateDB.SubRefund(params.SstoreClearsScheduleRefundEIP2200)
+		} else if value == (common.Hash{}) { // delete slot (2.2.1.2)
+			evm.StateDB.AddRefund(params.SstoreClearsScheduleRefundEIP2200)
+		}
+	}
+	if original == value {
+		if original == (common.Hash{}) { // reset to original inexistent slot (2.2.2.1)
+			evm.StateDB.AddRefund(params.SstoreSetGasEIP2200 - params.SloadGasEIP2200)
+		} else { // reset to original existing slot (2.2.2.2)
+			evm.StateDB.AddRefund(params.SstoreResetGasEIP2200 - params.SloadGasEIP2200)
+		}
+	}
+	return params.SloadGasEIP2200, nil // dirty update (2.2)
+}
+
 func makeGasLog(n uint64) gasFunc {
 	return func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
 		requestedSize, overflow := stack.Back(1).Uint64WithOverflow()
diff --git a/params/protocol_params.go b/params/protocol_params.go
index 5f154597a7fa..49d7e4de6747 100644
--- a/params/protocol_params.go
+++ b/params/protocol_params.go
@@ -55,6 +55,7 @@ const (
 
 	SstoreSentryGasEIP2200            uint64 = 2300  // Minimum gas required to be present for an SSTORE call, not consumed
 	SstoreSetGasEIP2200               uint64 = 20000 // Once per SSTORE operation from clean zero to non-zero
+	SstoreSetGasEIP5022               uint64 = 40000 // Once per SSTORE operation from clean zero to non-zero, after eip-5022
 	SstoreResetGasEIP2200             uint64 = 5000  // Once per SSTORE operation from clean non-zero to something else
 	SstoreClearsScheduleRefundEIP2200 uint64 = 15000 // Once per SSTORE operation for clearing an originally existing storage slot