[Flow EVM] extend EVM precompiles with cadence arch

fvm/evm/emulator/config.go

@@ -4,11 +4,13 @@ import (
 	"math"
 	"math/big"
 
-	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/core"
-	"github.com/ethereum/go-ethereum/core/vm"
-	"github.com/ethereum/go-ethereum/crypto"
-	"github.com/ethereum/go-ethereum/params"
+	gethCommon "github.com/ethereum/go-ethereum/common"
+	gethCore "github.com/ethereum/go-ethereum/core"
+	gethVM "github.com/ethereum/go-ethereum/core/vm"
+	gethCrypto "github.com/ethereum/go-ethereum/crypto"
+	gethParams "github.com/ethereum/go-ethereum/params"
+
+	"github.com/onflow/flow-go/fvm/evm/types"
 )
 
 var (
@@ -21,15 +23,24 @@ var (
 // Config sets the required parameters
 type Config struct {
 	// Chain Config
-	ChainConfig *params.ChainConfig
+	ChainConfig *gethParams.ChainConfig
 	// EVM config
-	EVMConfig vm.Config
+	EVMConfig gethVM.Config
 	// block context
-	BlockContext *vm.BlockContext
+	BlockContext *gethVM.BlockContext
 	// transaction context
-	TxContext *vm.TxContext
+	TxContext *gethVM.TxContext
 	// base unit of gas for direct calls
 	DirectCallBaseGasUsage uint64
+	// a set of extra precompiles to be injected
+	ExtraPrecompiles map[gethCommon.Address]gethVM.PrecompiledContract
+}
+
+func (c *Config) ChainRules() gethParams.Rules {
+	return c.ChainConfig.Rules(
+		c.BlockContext.BlockNumber,
+		c.BlockContext.Random != nil,
+		c.BlockContext.Time)
 }
 
 // DefaultChainConfig is the default chain config which
@@ -39,7 +50,7 @@ type Config struct {
 // For the future changes of EVM, we need to update the EVM go mod version
 // and set a proper height for the specific release based on the Flow EVM heights
 // so it could gets activated at a desired time.
-var DefaultChainConfig = &params.ChainConfig{
+var DefaultChainConfig = &gethParams.ChainConfig{
 	ChainID: FlowEVMTestnetChainID, // default is testnet
 
 	// Fork scheduling based on block heights
@@ -66,20 +77,20 @@ var DefaultChainConfig = &params.ChainConfig{
 func defaultConfig() *Config {
 	return &Config{
 		ChainConfig: DefaultChainConfig,
-		EVMConfig: vm.Config{
+		EVMConfig: gethVM.Config{
 			NoBaseFee: true,
 		},
-		TxContext: &vm.TxContext{
+		TxContext: &gethVM.TxContext{
 			GasPrice:   new(big.Int),
 			BlobFeeCap: new(big.Int),
 		},
-		BlockContext: &vm.BlockContext{
-			CanTransfer: core.CanTransfer,
-			Transfer:    core.Transfer,
+		BlockContext: &gethVM.BlockContext{
+			CanTransfer: gethCore.CanTransfer,
+			Transfer:    gethCore.Transfer,
 			GasLimit:    BlockLevelGasLimit, // block gas limit
 			BaseFee:     big.NewInt(0),
-			GetHash: func(n uint64) common.Hash { // default returns some random hash values
-				return common.BytesToHash(crypto.Keccak256([]byte(new(big.Int).SetUint64(n).String())))
+			GetHash: func(n uint64) gethCommon.Hash { // default returns some random hash values
+				return gethCommon.BytesToHash(gethCrypto.Keccak256([]byte(new(big.Int).SetUint64(n).String())))
 			},
 		},
 	}
@@ -114,7 +125,7 @@ func WithMainnetChainID() Option {
 }
 
 // WithOrigin sets the origin of the transaction (signer)
-func WithOrigin(origin common.Address) Option {
+func WithOrigin(origin gethCommon.Address) Option {
 	return func(c *Config) *Config {
 		c.TxContext.Origin = origin
 		return c
@@ -138,7 +149,7 @@ func WithGasLimit(gasLimit uint64) Option {
 }
 
 // WithCoinbase sets the coinbase of the block where the fees are collected in
-func WithCoinbase(coinbase common.Address) Option {
+func WithCoinbase(coinbase gethCommon.Address) Option {
 	return func(c *Config) *Config {
 		c.BlockContext.Coinbase = coinbase
 		return c
@@ -162,7 +173,7 @@ func WithBlockTime(time uint64) Option {
 }
 
 // WithGetBlockHashFunction sets the functionality to look up block hash by height
-func WithGetBlockHashFunction(getHash vm.GetHashFunc) Option {
+func WithGetBlockHashFunction(getHash gethVM.GetHashFunc) Option {
 	return func(c *Config) *Config {
 		c.BlockContext.GetHash = getHash
 		return c
@@ -176,3 +187,16 @@ func WithDirectCallBaseGasUsage(gas uint64) Option {
 		return c
 	}
 }
+
+// WithExtraPrecompiles appends precompile list with extra precompiles
+func WithExtraPrecompiles(precompiles []types.Precompile) Option {
+	return func(c *Config) *Config {
+		for _, pc := range precompiles {
+			if c.ExtraPrecompiles == nil {
+				c.ExtraPrecompiles = make(map[gethCommon.Address]gethVM.PrecompiledContract)
+			}
+			c.ExtraPrecompiles[pc.Address().ToCommon()] = pc
+		}
+		return c
+	}
+}

fvm/evm/emulator/emulator.go

@@ -39,6 +39,7 @@ func newConfig(ctx types.BlockContext) *Config {
 		WithBlockNumber(new(big.Int).SetUint64(ctx.BlockNumber)),
 		WithCoinbase(ctx.GasFeeCollector.ToCommon()),
 		WithDirectCallBaseGasUsage(ctx.DirectCallBaseGasUsage),
+		WithExtraPrecompiles(ctx.ExtraPrecompiles),
 	)
 }
 
@@ -53,6 +54,7 @@ func (em *Emulator) NewReadOnlyBlockView(ctx types.BlockContext) (types.ReadOnly
 // NewBlockView constructs a new block view (mutable)
 func (em *Emulator) NewBlockView(ctx types.BlockContext) (types.BlockView, error) {
 	cfg := newConfig(ctx)
+	SetupPrecompile(cfg)
 	return &BlockView{
 		config:   cfg,
 		rootAddr: em.rootAddr,
@@ -279,3 +281,25 @@ func (proc *procedure) run(msg *gethCore.Message, txType uint8) (*types.Result,
 	}
 	return &res, err
 }
+
+func SetupPrecompile(cfg *Config) {
+	rules := cfg.ChainRules()
+	// captures the pointer to the map that has to be augmented
+	var precompiles map[gethCommon.Address]gethVM.PrecompiledContract
+	switch {
+	case rules.IsCancun:
+		precompiles = gethVM.PrecompiledContractsCancun
+	case rules.IsBerlin:
+		precompiles = gethVM.PrecompiledContractsBerlin
+	case rules.IsIstanbul:
+		precompiles = gethVM.PrecompiledContractsIstanbul
+	case rules.IsByzantium:
+		precompiles = gethVM.PrecompiledContractsByzantium
+	default:
+		precompiles = gethVM.PrecompiledContractsHomestead
+	}
+	for addr, contract := range cfg.ExtraPrecompiles {
+		// we override if exist since we call this method on every block
+		precompiles[addr] = contract
+	}
+}

fvm/evm/emulator/emulator_test.go

@@ -335,7 +335,6 @@ func TestStorageNoSideEffect(t *testing.T) {
 			var err error
 			em := emulator.NewEmulator(backend, flowEVMRoot)
 			testAccount := types.NewAddressFromString("test")
-
 			amount := big.NewInt(10)
 			RunWithNewBlockView(t, em, func(blk types.BlockView) {
 				_, err = blk.DirectCall(types.NewDepositCall(testAccount, amount))
@@ -351,3 +350,80 @@ func TestStorageNoSideEffect(t *testing.T) {
 		})
 	})
 }
+
+func TestCallingExtraPrecompiles(t *testing.T) {
+	testutils.RunWithTestBackend(t, func(backend *testutils.TestBackend) {
+		testutils.RunWithTestFlowEVMRootAddress(t, backend, func(flowEVMRoot flow.Address) {
+			RunWithNewEmulator(t, backend, flowEVMRoot, func(em *emulator.Emulator) {
+
+				testAccount := types.NewAddressFromString("test")
+				amount := big.NewInt(10_000_000)
+				RunWithNewBlockView(t, em, func(blk types.BlockView) {
+					_, err := blk.DirectCall(types.NewDepositCall(testAccount, amount))
+					require.NoError(t, err)
+				})
+
+				input := []byte{1, 2}
+				output := []byte{3, 4}
+				addr := testutils.RandomAddress(t)
+				pc := &MockedPrecompile{
+					AddressFunc: func() types.Address {
+						return addr
+					},
+					RequiredGasFunc: func(input []byte) uint64 {
+						return uint64(10)
+					},
+					RunFunc: func(inp []byte) ([]byte, error) {
+						require.Equal(t, input, inp)
+						return output, nil
+					},
+				}
+
+				ctx := types.NewDefaultBlockContext(blockNumber.Uint64())
+				ctx.ExtraPrecompiles = []types.Precompile{pc}
+
+				blk, err := em.NewBlockView(ctx)
+				require.NoError(t, err)
+
+				res, err := blk.DirectCall(
+					types.NewContractCall(
+						testAccount,
+						types.NewAddress(addr.ToCommon()),
+						input,
+						1_000_000,
+						big.NewInt(0), // this should be zero because the contract doesn't have receiver
+					),
+				)
+				require.NoError(t, err)
+				require.Equal(t, output, res.ReturnedValue)
+			})
+		})
+	})
+}
+
+type MockedPrecompile struct {
+	AddressFunc     func() types.Address
+	RequiredGasFunc func(input []byte) uint64
+	RunFunc         func(input []byte) ([]byte, error)
+}
+
+func (mp *MockedPrecompile) Address() types.Address {
+	if mp.AddressFunc == nil {
+		panic("Address not set for the mocked precompile")
+	}
+	return mp.AddressFunc()
+}
+
+func (mp *MockedPrecompile) RequiredGas(input []byte) uint64 {
+	if mp.RequiredGasFunc == nil {
+		panic("RequiredGas not set for the mocked precompile")
+	}
+	return mp.RequiredGasFunc(input)
+}
+
+func (mp *MockedPrecompile) Run(input []byte) ([]byte, error) {
+	if mp.RunFunc == nil {
+		panic("Run not set for the mocked precompile")
+	}
+	return mp.RunFunc(input)
+}

fvm/evm/evm_test.go

@@ -225,11 +225,8 @@ func TestBridgedAccountWithdraw(t *testing.T) {
 	})
 }
 
-// TODO: provide proper contract code
 func TestBridgedAccountDeploy(t *testing.T) {
-
 	t.Parallel()
-
 	RunWithTestBackend(t, func(backend *testutils.TestBackend) {
 		RunWithTestFlowEVMRootAddress(t, backend, func(rootAddr flow.Address) {
 			tc := GetStorageTestContract(t)

fvm/evm/handler/addressAllocator.go

@@ -9,7 +9,18 @@ import (
 	"github.com/onflow/flow-go/model/flow"
 )
 
-const ledgerAddressAllocatorKey = "AddressAllocator"
+const (
+	ledgerAddressAllocatorKey = "AddressAllocator"
+	uint64ByteSize            = 8
+)
+
+var (
+	// prefixes:
+	// the first 12 bytes of addresses allocation
+	// leading zeros helps with storage and all zero is reserved for the EVM precompiles
+	FlowEVMPrecompileAddressPrefix = [...]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}
+	FlowEVMCOAAddressPrefix        = [...]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2}
+)
 
 type AddressAllocator struct {
 	led         atree.Ledger
@@ -26,8 +37,8 @@ func NewAddressAllocator(led atree.Ledger, flexAddress flow.Address) (*AddressAl
 	}, nil
 }
 
-// AllocateAddress allocates an address
-func (aa *AddressAllocator) AllocateAddress() (types.Address, error) {
+// AllocateCOAAddress allocates an address for COA
+func (aa *AddressAllocator) AllocateCOAAddress() (types.Address, error) {
 	data, err := aa.led.GetValue(aa.flexAddress[:], []byte(ledgerAddressAllocatorKey))
 	if err != nil {
 		return types.Address{}, err
@@ -38,10 +49,7 @@ func (aa *AddressAllocator) AllocateAddress() (types.Address, error) {
 		uuid = binary.BigEndian.Uint64(data)
 	}
 
-	target := types.Address{}
-	// first 12 bytes would be zero
-	// the next 8 bytes would be an increment of the UUID index
-	binary.BigEndian.PutUint64(target[12:], uuid)
+	target := MakeCOAAddress(uuid)
 
 	// store new uuid
 	newData := make([]byte, 8)
@@ -53,3 +61,24 @@ func (aa *AddressAllocator) AllocateAddress() (types.Address, error) {
 
 	return target, nil
 }
+
+func MakeCOAAddress(index uint64) types.Address {
+	var addr types.Address
+	prefixIndex := types.AddressLength - uint64ByteSize
+	copy(addr[:prefixIndex], FlowEVMCOAAddressPrefix[:])
+	binary.BigEndian.PutUint64(addr[prefixIndex:], index)
+	return addr
+}
+
+func (aa *AddressAllocator) AllocatePrecompileAddress(index uint64) types.Address {
+	target := MakePrecompileAddress(index)
+	return target
+}
+
+func MakePrecompileAddress(index uint64) types.Address {
+	var addr types.Address
+	prefixIndex := types.AddressLength - uint64ByteSize
+	copy(addr[:prefixIndex], FlowEVMPrecompileAddressPrefix[:])
+	binary.BigEndian.PutUint64(addr[prefixIndex:], index)
+	return addr
+}

fvm/evm/handler/addressAllocator_test.go

@@ -19,16 +19,20 @@ func TestAddressAllocator(t *testing.T) {
 			aa, err := handler.NewAddressAllocator(backend, root)
 			require.NoError(t, err)
 
+			adr := aa.AllocatePrecompileAddress(3)
+			expectedAddress := types.NewAddress(gethCommon.HexToAddress("0x0000000000000000000000010000000000000003"))
+			require.Equal(t, expectedAddress, adr)
+
 			// test default value fall back
-			adr, err := aa.AllocateAddress()
+			adr, err = aa.AllocateCOAAddress()
 			require.NoError(t, err)
-			expectedAddress := types.NewAddress(gethCommon.HexToAddress("0x00000000000000000001"))
+			expectedAddress = types.NewAddress(gethCommon.HexToAddress("0x0000000000000000000000020000000000000001"))
 			require.Equal(t, expectedAddress, adr)
 
 			// continous allocation logic
-			adr, err = aa.AllocateAddress()
+			adr, err = aa.AllocateCOAAddress()
 			require.NoError(t, err)
-			expectedAddress = types.NewAddress(gethCommon.HexToAddress("0x00000000000000000002"))
+			expectedAddress = types.NewAddress(gethCommon.HexToAddress("0x0000000000000000000000020000000000000002"))
 			require.Equal(t, expectedAddress, adr)
 		})