Skip to content

Commit

Permalink
Document the Tier enum and constants that come from Execution Specs
Browse files Browse the repository at this point in the history
  • Loading branch information
@cameel
cameel committed Feb 8, 2024
1 parent 733896d commit d5123c6
Show file tree
Hide file tree
Showing 2 changed files with 44 additions and 37 deletions.
56 changes: 29 additions & 27 deletions libevmasm/GasMeter.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -43,32 +43,34 @@ class KnownState;

namespace GasCosts
{
/// NOTE: The GAS_... constants referenced by comments are defined for each EVM version in the Execution Specs:
/// https://ethereum.github.io/execution-specs/autoapi/ethereum/<evm version>/vm/gas/index.html

static unsigned const stackLimit = 1024;
static unsigned const tier0Gas = 0;
static unsigned const tier1Gas = 2;
static unsigned const tier2Gas = 3;
static unsigned const tier3Gas = 5;
static unsigned const tier4Gas = 8;
static unsigned const tier5Gas = 10;
static unsigned const tier6Gas = 20;
static unsigned const tier7Gas = 0;
static unsigned const expGas = 10;
static unsigned const tier0Gas = 0; // GAS_ZERO (in Execution Specs)
static unsigned const tier1Gas = 2; // GAS_BASE
static unsigned const tier2Gas = 3; // GAS_VERY_LOW
static unsigned const tier3Gas = 5; // GAS_LOW / GAS_FAST_STEP
static unsigned const tier4Gas = 8; // GAS_MID
static unsigned const tier5Gas = 10; // GAS_HIGH
static unsigned const tier6Gas = 20; // GAS_BLOCK_HASH
static unsigned const expGas = 10; // GAS_EXPONENTIATION
inline unsigned expByteGas(langutil::EVMVersion _evmVersion)
{
return _evmVersion >= langutil::EVMVersion::spuriousDragon() ? 50 : 10;
return _evmVersion >= langutil::EVMVersion::spuriousDragon() ? 50 : 10; // GAS_EXPONENTIATION_PER_BYTE
}
static unsigned const keccak256Gas = 30;
static unsigned const keccak256WordGas = 6;
static unsigned const keccak256Gas = 30; // GAS_KECCAK256
static unsigned const keccak256WordGas = 6; // GAS_KECCAK256_WORD
/// Corresponds to ACCESS_LIST_ADDRESS_COST from EIP-2930
static unsigned const accessListAddressCost = 2400;
/// Corresponds to ACCESS_LIST_STORAGE_COST from EIP-2930
static unsigned const accessListStorageKeyCost = 1900;
/// Corresponds to COLD_SLOAD_COST from EIP-2929
static unsigned const coldSloadCost = 2100;
static unsigned const coldSloadCost = 2100; // GAS_COLD_SLOAD
/// Corresponds to COLD_ACCOUNT_ACCESS_COST from EIP-2929
static unsigned const coldAccountAccessCost = 2600;
static unsigned const coldAccountAccessCost = 2600; // GAS_COLD_ACCOUNT_ACCESS
/// Corresponds to WARM_STORAGE_READ_COST from EIP-2929
static unsigned const warmStorageReadCost = 100;
static unsigned const warmStorageReadCost = 100; // GAS_WARM_ACCESS
inline unsigned sloadGas(langutil::EVMVersion _evmVersion)
{
if (_evmVersion >= langutil::EVMVersion::berlin())
Expand All @@ -81,7 +83,7 @@ namespace GasCosts
return 50;
}
/// Corresponds to SSTORE_SET_GAS
static unsigned const sstoreSetGas = 20000;
static unsigned const sstoreSetGas = 20000; // GAS_STORAGE_SET
/// Corresponds to SSTORE_RESET_GAS from EIP-2929
static unsigned const sstoreResetGas = 5000 - coldSloadCost;
/// Corresponds to SSTORE_CLEARS_SCHEDULE from EIP-2200
Expand Down Expand Up @@ -130,11 +132,11 @@ namespace GasCosts
else
return 20;
}
static unsigned const jumpdestGas = 1;
static unsigned const logGas = 375;
static unsigned const logDataGas = 8;
static unsigned const logTopicGas = 375;
static unsigned const createGas = 32000;
static unsigned const jumpdestGas = 1; // GAS_JUMPDEST
static unsigned const logGas = 375; // GAS_LOG
static unsigned const logDataGas = 8; // GAS_LOG_DATA
static unsigned const logTopicGas = 375; // GAS_LOG_TOPIC
static unsigned const createGas = 32000; // GAS_CREATE
inline unsigned callGas(langutil::EVMVersion _evmVersion)
{
if (_evmVersion >= langutil::EVMVersion::berlin())
Expand All @@ -144,10 +146,10 @@ namespace GasCosts
else
return 40;
}
static unsigned const callStipend = 2300;
static unsigned const callValueTransferGas = 9000;
static unsigned const callNewAccountGas = 25000;
inline unsigned selfdestructGas(langutil::EVMVersion _evmVersion)
static unsigned const callStipend = 2300; // GAS_CALL_STIPEND
static unsigned const callValueTransferGas = 9000; // GAS_CALL_VALUE
static unsigned const callNewAccountGas = 25000; // GAS_NEW_ACCOUNT / GAS_SELF_DESTRUCT_NEW_ACCOUNT
inline unsigned selfdestructGas(langutil::EVMVersion _evmVersion) // GAS_SELF_DESTRUCT
{
if (_evmVersion >= langutil::EVMVersion::berlin())
return coldAccountAccessCost;
Expand All @@ -164,9 +166,9 @@ namespace GasCosts
else
return 24000;
}
static unsigned const memoryGas = 3;
static unsigned const memoryGas = 3; // GAS_MEMORY / GAS_COPY / GAS_RETURN_DATA_COPY
static unsigned const quadCoeffDiv = 512;
static unsigned const createDataGas = 200;
static unsigned const createDataGas = 200; // GAS_CODE_DEPOSIT
static unsigned const txGas = 21000;
static unsigned const txCreateGas = 53000;
static unsigned const txDataZeroGas = 4;
Expand Down
25 changes: 15 additions & 10 deletions libevmasm/Instruction.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -287,18 +287,23 @@ inline Instruction logInstruction(unsigned _number)
return Instruction(unsigned(Instruction::LOG0) + _number);
}

/// Gas price tiers representing static cost of an instruction.
/// Opcodes whose cost is dynamic or depends on EVM version should use the `Special` tier and need
/// dedicated logic in GasMeter (especially in estimateMax()).
/// The tiers loosely follow opcode groups originally defined in the Yellow Paper.
enum class Tier
{
Zero = 0, // 0, Zero
Base, // 2, Quick
VeryLow, // 3, Fastest
Low, // 5, Fast
Mid, // 8, Mid
High, // 10, Slow
Ext, // 20, Ext
WarmAccess, // 100, Warm Access
Special, // multiparam or otherwise special
Invalid // Invalid.
// NOTE: Tiers should be ordered by cost, since we sometimes perform comparisons between them.
Zero = 0, // 0, Zero
Base, // 2, Quick
VeryLow, // 3, Fastest
Low, // 5, Fast
Mid, // 8, Mid
High, // 10, Slow
Ext, // 20, Ext
WarmAccess, // 100, Warm Access
Special, // multiparam or otherwise special
Invalid, // Invalid.
};

/// Information structure for a particular instruction.
Expand Down

0 comments on commit d5123c6

Please sign in to comment.