imp(vm): Interpreter interface (backport ethereum#2) (ethereum#12)

Co-authored-by: Federico Kunze Küllmer <[email protected]>
Co-authored-by: Freddy Caceres <[email protected]>

CHANGELOG.md

@@ -0,0 +1,43 @@
+
+<!--
+Guiding Principles:
+
+Changelogs are for humans, not machines.
+There should be an entry for every single version.
+The same types of changes should be grouped.
+Versions and sections should be linkable.
+The latest version comes first.
+The release date of each version is displayed.
+Mention whether you follow Semantic Versioning.
+
+Usage:
+
+Change log entries are to be added to the Unreleased section under the
+appropriate stanza (see below). Each entry should ideally include a tag and
+the Github issue reference in the following format:
+
+* (<tag>) \#<issue-number> message
+
+The issue numbers will later be link-ified during the release process so you do
+not have to worry about including a link manually, but you can if you wish.
+
+Types of changes (Stanzas):
+
+"Features" for new features.
+"Improvements" for changes in existing functionality.
+"Deprecated" for soon-to-be removed features.
+"Bug Fixes" for any bug fixes.
+"Client Breaking" for breaking CLI commands and REST routes used by end-users.
+"API Breaking" for breaking exported APIs used by developers building on SDK.
+"State Machine Breaking" for any changes that result in a different AppState given same genesisState and txList.
+
+Ref: https://keepachangelog.com/en/1.0.0/
+-->
+
+# Changelog
+
+## Unreleased
+
+### Improvements
+
+* [#2](https://github.com/evmos/go-ethereum/pull/2) Define `Interpreter` interface for the EVM.

core/vm/evm.go

@@ -113,7 +113,7 @@ type EVM struct {
 	Config Config
 	// global (to this context) ethereum virtual machine
 	// used throughout the execution of the tx.
-	interpreter *EVMInterpreter
+	interpreter Interpreter
 	// abort is used to abort the EVM calling operations
 	// NOTE: must be set atomically
 	abort int32
@@ -134,6 +134,7 @@ func NewEVM(blockCtx BlockContext, txCtx TxContext, statedb StateDB, chainConfig
 		chainConfig: chainConfig,
 		chainRules:  chainConfig.Rules(blockCtx.BlockNumber, blockCtx.Random != nil),
 	}
+
 	evm.interpreter = NewEVMInterpreter(evm, config)
 	return evm
 }
@@ -157,10 +158,15 @@ func (evm *EVM) Cancelled() bool {
 }
 
 // Interpreter returns the current interpreter
-func (evm *EVM) Interpreter() *EVMInterpreter {
+func (evm *EVM) Interpreter() Interpreter {
 	return evm.interpreter
 }
 
+// WithInterpreter sets the interpreter to the EVM instance
+func (evm *EVM) WithInterpreter(interpreter Interpreter) {
+	evm.interpreter = interpreter
+}
+
 // Call executes the contract associated with the addr with the given input as
 // parameters. It also handles any necessary value transfer required and takes
 // the necessary steps to create accounts and reverses the state in case of an
@@ -263,7 +269,7 @@ func (evm *EVM) CallCode(caller ContractRef, addr common.Address, input []byte,
 	if !evm.Context.CanTransfer(evm.StateDB, caller.Address(), value) {
 		return nil, gas, ErrInsufficientBalance
 	}
-	var snapshot = evm.StateDB.Snapshot()
+	snapshot := evm.StateDB.Snapshot()
 
 	// Invoke tracer hooks that signal entering/exiting a call frame
 	if evm.Config.Debug {
@@ -304,7 +310,7 @@ func (evm *EVM) DelegateCall(caller ContractRef, addr common.Address, input []by
 	if evm.depth > int(params.CallCreateDepth) {
 		return nil, gas, ErrDepth
 	}
-	var snapshot = evm.StateDB.Snapshot()
+	snapshot := evm.StateDB.Snapshot()
 
 	// Invoke tracer hooks that signal entering/exiting a call frame
 	if evm.Config.Debug {
@@ -348,7 +354,7 @@ func (evm *EVM) StaticCall(caller ContractRef, addr common.Address, input []byte
 	// after all empty accounts were deleted, so this is not required. However, if we omit this,
 	// then certain tests start failing; stRevertTest/RevertPrecompiledTouchExactOOG.json.
 	// We could change this, but for now it's left for legacy reasons
-	var snapshot = evm.StateDB.Snapshot()
+	snapshot := evm.StateDB.Snapshot()
 
 	// We do an AddBalance of zero here, just in order to trigger a touch.
 	// This doesn't matter on Mainnet, where all empties are gone at the time of Byzantium,

core/vm/instructions_test.go

@@ -41,9 +41,11 @@ type twoOperandParams struct {
 	y string
 }
 
-var alphabetSoup = "ABCDEF090807060504030201ffffffffffffffffffffffffffffffffffffffff"
-var commonParams []*twoOperandParams
-var twoOpMethods map[string]executionFunc
+var (
+	alphabetSoup = "ABCDEF090807060504030201ffffffffffffffffffffffffffffffffffffffff"
+	commonParams []*twoOperandParams
+	twoOpMethods map[string]executionFunc
+)
 
 func init() {
 	// Params is a list of common edgecases that should be used for some common tests
@@ -92,10 +94,10 @@ func init() {
 
 func testTwoOperandOp(t *testing.T, tests []TwoOperandTestcase, opFn executionFunc, name string) {
 	var (
-		env            = NewEVM(BlockContext{}, TxContext{}, nil, params.TestChainConfig, Config{})
-		stack          = newstack()
-		pc             = uint64(0)
-		evmInterpreter = env.interpreter
+		env         = NewEVM(BlockContext{}, TxContext{}, nil, params.TestChainConfig, Config{})
+		stack       = newstack()
+		pc          = uint64(0)
+		interpreter = env.interpreter
 	)
 
 	for i, test := range tests {
@@ -104,7 +106,7 @@ func testTwoOperandOp(t *testing.T, tests []TwoOperandTestcase, opFn executionFu
 		expected := new(uint256.Int).SetBytes(common.Hex2Bytes(test.Expected))
 		stack.push(x)
 		stack.push(y)
-		opFn(&pc, evmInterpreter, &ScopeContext{nil, stack, nil})
+		opFn(&pc, interpreter.(*EVMInterpreter), &ScopeContext{nil, stack, nil})
 		if len(stack.data) != 1 {
 			t.Errorf("Expected one item on stack after %v, got %d: ", name, len(stack.data))
 		}
@@ -202,7 +204,8 @@ func TestAddMod(t *testing.T) {
 		z        string
 		expected string
 	}{
-		{"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+		{
+			"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
 			"fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe",
 			"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
 			"fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe",
@@ -246,7 +249,7 @@ func TestWriteExpectedValues(t *testing.T) {
 			y := new(uint256.Int).SetBytes(common.Hex2Bytes(param.y))
 			stack.push(x)
 			stack.push(y)
-			opFn(&pc, interpreter, &ScopeContext{nil, stack, nil})
+			opFn(&pc, interpreter.(*EVMInterpreter), &ScopeContext{nil, stack, nil})
 			actual := stack.pop()
 			result[i] = TwoOperandTestcase{param.x, param.y, fmt.Sprintf("%064x", actual)}
 		}
@@ -258,7 +261,7 @@ func TestWriteExpectedValues(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
-		_ = os.WriteFile(fmt.Sprintf("testdata/testcases_%v.json", name), data, 0644)
+		_ = os.WriteFile(fmt.Sprintf("testdata/testcases_%v.json", name), data, 0o644)
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -447,11 +450,13 @@ func BenchmarkOpEq(b *testing.B) {
 
 	opBenchmark(b, opEq, x, y)
 }
+
 func BenchmarkOpEq2(b *testing.B) {
 	x := "FBCDEF090807060504030201ffffffffFBCDEF090807060504030201ffffffff"
 	y := "FBCDEF090807060504030201ffffffffFBCDEF090807060504030201fffffffe"
 	opBenchmark(b, opEq, x, y)
 }
+
 func BenchmarkOpAnd(b *testing.B) {
 	x := alphabetSoup
 	y := alphabetSoup
@@ -502,18 +507,21 @@ func BenchmarkOpSHL(b *testing.B) {
 
 	opBenchmark(b, opSHL, x, y)
 }
+
 func BenchmarkOpSHR(b *testing.B) {
 	x := "FBCDEF090807060504030201ffffffffFBCDEF090807060504030201ffffffff"
 	y := "ff"
 
 	opBenchmark(b, opSHR, x, y)
 }
+
 func BenchmarkOpSAR(b *testing.B) {
 	x := "FBCDEF090807060504030201ffffffffFBCDEF090807060504030201ffffffff"
 	y := "ff"
 
 	opBenchmark(b, opSAR, x, y)
 }
+
 func BenchmarkOpIsZero(b *testing.B) {
 	x := "FBCDEF090807060504030201ffffffffFBCDEF090807060504030201ffffffff"
 	opBenchmark(b, opIszero, x)
@@ -673,12 +681,12 @@ func TestRandom(t *testing.T) {
 		{name: "hash(0x010203)", random: crypto.Keccak256Hash([]byte{0x01, 0x02, 0x03})},
 	} {
 		var (
-			env            = NewEVM(BlockContext{Random: &tt.random}, TxContext{}, nil, params.TestChainConfig, Config{})
-			stack          = newstack()
-			pc             = uint64(0)
-			evmInterpreter = env.interpreter
+			env         = NewEVM(BlockContext{Random: &tt.random}, TxContext{}, nil, params.TestChainConfig, Config{})
+			stack       = newstack()
+			pc          = uint64(0)
+			interpreter = env.interpreter
 		)
-		opRandom(&pc, evmInterpreter, &ScopeContext{nil, stack, nil})
+		opRandom(&pc, interpreter.(*EVMInterpreter), &ScopeContext{nil, stack, nil})
 		if len(stack.data) != 1 {
 			t.Errorf("Expected one item on stack after %v, got %d: ", tt.name, len(stack.data))
 		}

core/vm/interface.go

@@ -88,3 +88,13 @@ type CallContext interface {
 	// Create a new contract
 	Create(env *EVM, me ContractRef, data []byte, gas, value *big.Int) ([]byte, common.Address, error)
 }
+
+// Interpreter is used to run Ethereum based contracts and will utilize the
+// passed environment to query external sources for state information.
+// The Interpreter will run the byte code VM based on the passed
+// configuration.
+type Interpreter interface {
+	// Run loops and evaluates the contract's code with the given input data and returns
+	// the return byte-slice and an error if one occurred.
+	Run(contract *Contract, input []byte, static bool) ([]byte, error)
+}

core/vm/interpreter.go

@@ -52,6 +52,8 @@ type keccakState interface {
 	Read([]byte) (int, error)
 }
 
+var _ Interpreter = &EVMInterpreter{}
+
 // EVMInterpreter represents an EVM interpreter
 type EVMInterpreter struct {
 	evm *EVM