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core/vm: hoist jumptable nil-check out of the interpreter loop #32068

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core/vm: hoist jumptable nil-check out of the interpreter loop #32068

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12 changes: 7 additions & 5 deletions core/vm/interpreter.go
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Original file line number Diff line number Diff line change
Expand Up @@ -181,10 +181,11 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
}

var (
op OpCode // current opcode
mem = NewMemory() // bound memory
stack = newstack() // local stack
callContext = &ScopeContext{
op OpCode // current opcode
jumpTable *JumpTable = in.table
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I wonder why it's a pointer at all

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I guess to avoid 2KB copies on each interpreter creation.

mem = NewMemory() // bound memory
stack = newstack() // local stack
callContext = &ScopeContext{
Memory: mem,
Stack: stack,
Contract: contract,
Expand Down Expand Up @@ -227,6 +228,7 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
// explicit STOP, RETURN or SELFDESTRUCT is executed, an error occurred during
// the execution of one of the operations or until the done flag is set by the
// parent context.
_ = jumpTable[0] // nil-check the jumpTable out of the loop
for {
if debug {
// Capture pre-execution values for tracing.
Expand All @@ -247,7 +249,7 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
// Get the operation from the jump table and validate the stack to ensure there are
// enough stack items available to perform the operation.
op = contract.GetOp(pc)
operation := in.table[op]
operation := jumpTable[op]
cost = operation.constantGas // For tracing
// Validate stack
if sLen := stack.len(); sLen < operation.minStack {
Expand Down
18 changes: 18 additions & 0 deletions core/vm/interpreter_test.go
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Expand Up @@ -26,6 +26,7 @@ import (
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/params"
"github.com/holiman/uint256"
"github.com/stretchr/testify/require"
)

var loopInterruptTests = []string{
Expand Down Expand Up @@ -74,3 +75,20 @@ func TestLoopInterrupt(t *testing.T) {
}
}
}

func BenchmarkLoop(b *testing.B) {
address := common.BytesToAddress([]byte("contract"))
vmctx := BlockContext{
Transfer: func(StateDB, common.Address, common.Address, *uint256.Int) {},
}

statedb, _ := state.New(types.EmptyRootHash, state.NewDatabaseForTesting())
statedb.CreateAccount(address)
statedb.SetCode(address, common.Hex2Bytes(loopInterruptTests[0]))
statedb.Finalise(true)

evm := NewEVM(vmctx, statedb, params.AllEthashProtocolChanges, Config{})
b.ResetTimer()
_, _, err := evm.Call(common.Address{}, address, nil, uint64(b.N*100), new(uint256.Int))
require.EqualError(b, err, ErrOutOfGas.Error())
}