feat: Gas params

[rakita]

A way to configure all gas-related parameters in EVM so we can easily change dynamic part of gas of opcode.

[codspeed-hq]

CodSpeed Performance Report

Merging #3132 will degrade performances by 3.96%

_{Comparing rakita/gas-params (53141bd) with main (9afd166)}

Summary

❌ 2 regressions
✅ 171 untouched

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
❌	transfer_finalize	17 µs	17.7 µs	-3.96%
❌	transfer	13.9 µs	14.5 µs	-3.92%

[rakita]

MCOPY has a static VERY_LOG gas

revm/crates/interpreter/src/instructions/memory.rs

Line 68 in d0bb48e

gas_or_fail!(context.interpreter, gas::copy_cost_verylow(len));

VERYLOW is 3gas.

revm/crates/interpreter/src/gas/calc.rs

Lines 110 to 111 in d0bb48e

	pub const fn copy_cost_verylow(len: usize) -> Option<u64> {
	copy_cost(VERYLOW, len)

[rakita]

revm/crates/interpreter/src/gas/constants.rs

Lines 7 to 8 in fdf606d

	pub const VERYLOW: u64 = 3;
	/// Gas cost for DATALOADN instruction.

[rakita]

This logic is moved to selfdestruct instruction:

revm/crates/interpreter/src/instructions/host.rs

Lines 379 to 385 in 403f28f

	// EIP-161: State trie clearing (invariant-preserving alternative)
	let should_charge_topup = if spec.is_enabled_in(SpecId::SPURIOUS_DRAGON) {
	res.had_value && !res.target_exists
	} else {
	!res.target_exists
	};

[rakita]

moved to static gas

[rakita]

moved to parent call here

https://github.com/bluealloy/revm/pull/3132/files#diff-67852b4107a0dfcff4283ce22ed74377355b616319ae786de7ff81284a9f679bL64-R68

[rakita]

Part of static gas

[rakita]

Frontier part as it has special logic is moved here:

revm/crates/interpreter/src/gas/params.rs

Lines 271 to 281 in 403f28f

	pub fn sstore_dynamic_gas(&self, is_istanbul: bool, vals: &SStoreResult, is_cold: bool) -> u64 {
	// frontier logic gets charged for every SSTORE operation if original value is zero.
	// this behaviour is fixed in istanbul fork.
	if !is_istanbul {
	if vals.is_present_zero() && !vals.is_new_zero() {
	return self.sstore_set_without_load_cost();
	} else {
	return self.sstore_reset_without_cold_load_cost();
	}
	}

This is without load cost that is now part of static instruction gas

[rakita]

is cold is now always added but cold cost is zero before berlin here:

revm/crates/interpreter/src/gas/params.rs

Lines 284 to 288 in 403f28f

	// this will be zero before berlin fork.
	if is_cold {
	gas += self.cold_storage_cost();
	}

[rakita]

This code is slighly changes as SLOAD_GAS is not part of the static instruction gas. So we have fewer branches

It is easy to follow commnets

revm/crates/interpreter/src/gas/params.rs

Lines 289 to 300 in 403f28f

	// if new values changed present value and present value is unchanged from original.
	if vals.new_values_changes_present() && vals.is_original_eq_present() {
	gas += if vals.is_original_zero() {
	// set cost for creating storage slot (Zero slot means it is not existing).
	// and previous condition says present is same as original.
	self.sstore_set_without_load_cost()
	} else {
	// if new value is not zero, this means we are setting some value to it.
	self.sstore_reset_without_cold_load_cost()
	};
	}
	gas

[rakita]

This is moved to a variable inside GasParams.

revm/crates/interpreter/src/gas/params.rs

Line 157 in 403f28f

table[GasId::sstore_static().as_usize()] = gas::WARM_STORAGE_READ_COST;

revm/crates/interpreter/src/gas/params.rs

Line 149 in 403f28f

table[GasId::sstore_static().as_usize()] = gas::ISTANBUL_SLOAD_GAS;

revm/crates/interpreter/src/gas/params.rs

Line 127 in 403f28f

table[GasId::sstore_static().as_usize()] = 5000;

[rakita]

Has become part of static instruction gas.

And additional gas is handled here:

revm/crates/interpreter/src/instructions/host.rs

Lines 193 to 210 in 403f28f

	pub fn sload<WIRE: InterpreterTypes, H: Host + ?Sized>(context: InstructionContext<'_, H, WIRE>) {
	popn_top!([], index, context.interpreter);
	let spec_id = context.interpreter.runtime_flag.spec_id();
	let target = context.interpreter.input.target_address();
	if spec_id.is_enabled_in(BERLIN) {
	let additional_cold_cost = context
	.interpreter
	.gas_params
	.cold_storage_additional_cost();
	let skip_cold = context.interpreter.gas.remaining() < additional_cold_cost;
	let res = context.host.sload_skip_cold_load(target, *index, skip_cold);
	match res {
	Ok(storage) => {
	if storage.is_cold {
	gas!(context.interpreter, additional_cold_cost);
	}

[rakita]

Dynamic part is in GasParams here:

revm/crates/interpreter/src/gas/params.rs

Lines 193 to 201 in 403f28f

	pub fn exp_cost(&self, power: U256) -> u64 {
	if power.is_zero() {
	return 0;
	}
	// EIP-160: EXP cost increase
	self.get(GasId::exp_byte_gas())
	.saturating_mul(log2floor(power) / 8 + 1)
	}

revm/crates/interpreter/src/gas/params.rs

Lines 144 to 147 in 403f28f

	if spec.is_enabled_in(SpecId::SPURIOUS_DRAGON) {
	table[GasId::exp_byte_gas().as_usize()] = 50;
	}

revm/crates/interpreter/src/gas/params.rs

Lines 110 to 111 in 403f28f

	table[GasId::exp_byte_gas().as_usize()] = 10;
	table[GasId::logdata().as_usize()] = gas::LOGDATA;

And static part (EXP) is now part of static instruction gas

[rakita]

Fully moved to:

revm/crates/interpreter/src/gas/params.rs

Lines 399 to 405 in 403f28f

	pub fn create2_cost(&self, len: usize) -> u64 {
	self.get(GasId::create()).saturating_add(
	self.get(GasId::keccak256_per_word())
	.saturating_mul(num_words(len) as u64),
	)
	}

revm/crates/interpreter/src/gas/params.rs

Line 120 in 403f28f

table[GasId::create().as_usize()] = gas::CREATE;

revm/crates/interpreter/src/gas/params.rs

Line 116 in 403f28f

table[GasId::keccak256_per_word().as_usize()] = gas::KECCAK256WORD;

[rakita]

before instanbul is moved here:

revm/crates/interpreter/src/gas/params.rs

Lines 305 to 316 in 403f28f

	pub fn sstore_refund(&self, is_istanbul: bool, vals: &SStoreResult) -> i64 {
	// EIP-3529: Reduction in refunds
	let sstore_clearing_slot_refund = self.sstore_clearing_slot_refund() as i64;
	if !is_istanbul {
	// // before istanbul fork, refund was always awarded without checking original state.
	if !vals.is_present_zero() && vals.is_new_zero() {
	return sstore_clearing_slot_refund;
	}
	return 0;
	}

[rakita]

part where we return zero is now here

revm/crates/interpreter/src/gas/params.rs

Lines 317 to 321 in 403f28f

	// If current value equals new value (this is a no-op)
	if vals.is_new_eq_present() {
	return 0;
	}

[rakita]

This part is not refactored here

revm/crates/interpreter/src/gas/params.rs

Lines 322 to 327 in 403f28f

	// refund for the clearing of storage slot.
	// As new is not equal to present, new values zero means that original and present values are not zero
	if vals.is_original_eq_present() && vals.is_new_zero() {
	return sstore_clearing_slot_refund;
	}

[rakita]

And last part is now here. Added additional comments from EIP

revm/crates/interpreter/src/gas/params.rs

Lines 328 to 355 in 403f28f

	let mut refund = 0;
	// If original value is not 0
	if !vals.is_original_zero() {
	// If current value is 0 (also means that new value is not 0),
	if vals.is_present_zero() {
	// remove SSTORE_CLEARS_SCHEDULE gas from refund counter.
	refund -= sstore_clearing_slot_refund;
	// If new value is 0 (also means that current value is not 0),
	} else if vals.is_new_zero() {
	// add SSTORE_CLEARS_SCHEDULE gas to refund counter.
	refund += sstore_clearing_slot_refund;
	}
	}
	// If original value equals new value (this storage slot is reset)
	if vals.is_original_eq_new() {
	// If original value is 0
	if vals.is_original_zero() {
	// add SSTORE_SET_GAS - SLOAD_GAS to refund counter.
	refund += self.sstore_set_without_load_cost() as i64;
	// Otherwise
	} else {
	// add SSTORE_RESET_GAS - SLOAD_GAS gas to refund counter.
	refund += self.sstore_reset_without_cold_load_cost() as i64;
	}
	}
	refund
	}

[Copilot]

Pull Request Overview

This PR introduces a configurable gas parameters system (GasParams) for the EVM interpreter, enabling easy modification of dynamic gas costs for opcodes. The implementation replaces hardcoded gas calculations with a flexible, spec-aware table-based approach.

Key Changes:

• Introduced GasParams struct with gas cost table that adapts based on EVM spec version
• Refactored all instruction implementations to use GasParams instead of direct gas constant references
• Updated memory resize operations to accept and use GasParams
• Added gas parameter configuration in handler initialization
• Enhanced test script with --keep-going flag support

Reviewed Changes

Copilot reviewed 28 out of 28 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
scripts/run-tests.sh	Added --keep-going flag support for continuing tests after failures
crates/interpreter/src/gas/params.rs	New core gas parameters implementation with configurable gas table
crates/interpreter/src/interpreter.rs	Integrated GasParams into interpreter struct and initialization
crates/interpreter/src/interpreter/shared_memory.rs	Updated memory resize to use GasParams and return Result
crates/interpreter/src/instructions/*.rs	Refactored all instruction gas calculations to use GasParams
crates/interpreter/src/gas/*.rs	Removed deprecated gas calculation functions, kept core utilities
crates/handler/src/*.rs	Updated handler to configure gas parameters based on spec
crates/context/src/journal/inner.rs	Minor type alias cleanup
crates/context/interface/src/context.rs	Added helper methods to SStoreResult

---

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[rakita]

Moved to:

revm/crates/interpreter/src/gas/params.rs

Lines 442 to 453 in 0ee23df

	/// New account cost. New account cost is added to the gas cost if the account is empty.
	#[inline]
	pub fn new_account_cost(&self, is_spurious_dragon: bool, transfers_value: bool) -> u64 {
	// EIP-161: State trie clearing (invariant-preserving alternative)
	// Pre-Spurious Dragon: always charge for new account
	// Post-Spurious Dragon: only charge if value is transferred
	if !is_spurious_dragon || transfers_value {
	return self.get(GasId::new_account_cost());
	}
	0
	}

[klkvr]

will this not work properly now for any impl overriding this trait? i don't think this is acceptable and we need to either hide this deeper or make it so this change is obvious from compilation issues after the bump