Add custom registered precompiles to the active precompile list

core/vm/contracts.go

@@ -34,6 +34,7 @@ import (
 	"github.com/ethereum/go-ethereum/crypto/kzg4844"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/precompile/contract"
+	"github.com/ethereum/go-ethereum/precompile/modules"
 	"golang.org/x/crypto/ripemd160"
 )
 
@@ -151,19 +152,29 @@ func init() {
 }
 
 // ActivePrecompiles returns the precompiles enabled with the current configuration.
-func ActivePrecompiles(rules params.Rules) []common.Address {
+func ActivePrecompiles(rules params.Rules) (precompiles []common.Address) {
 	switch {
 	case rules.IsCancun:
-		return PrecompiledAddressesCancun
+		precompiles = PrecompiledAddressesCancun
 	case rules.IsBerlin:
-		return PrecompiledAddressesBerlin
+		precompiles = PrecompiledAddressesBerlin
+
 	case rules.IsIstanbul:
-		return PrecompiledAddressesIstanbul
+		precompiles = PrecompiledAddressesIstanbul
 	case rules.IsByzantium:
-		return PrecompiledAddressesByzantium
+		precompiles = PrecompiledAddressesByzantium
 	default:
-		return PrecompiledAddressesHomestead
+		precompiles = PrecompiledAddressesHomestead
+	}
+
+	// TODO: Consider performance improvements here to prevent iteration & allocations on every call.
+	// NOTE: If using init to cache addresses, then some care should be taken to ensure all precompiles are
+	// registered before being cached here.
+	for _, precompile := range modules.RegisteredModules() {
+		precompiles = append(precompiles, precompile.Address)
 	}
+
+	return precompiles
 }
 
 // RunPrecompiledContract runs and evaluates the output of a precompiled contract.

core/vm/precompile_test.go

@@ -1,8 +1,11 @@
 package vm
 
 import (
+	"math/big"
 	"testing"
+	"time"
 
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -54,3 +57,71 @@ func TestEvmIsPrecompileMethod(t *testing.T) {
 	require.False(t, ok)
 	require.Nil(t, precompiledContract)
 }
+
+func TestActivePrecompiles(t *testing.T) {
+	genesisTime := time.Now()
+	getBlockTime := func(height *big.Int) *uint64 {
+		if !height.IsInt64() {
+			t.Fatalf("expected height bounded to int64")
+		}
+		totalBlockSeconds := time.Duration(10*height.Int64()) * time.Second
+		blockTimeUnix := uint64(genesisTime.Add(totalBlockSeconds).Unix())
+
+		return &blockTimeUnix
+	}
+	chainConfig := params.TestChainConfig
+	chainConfig.HomesteadBlock = big.NewInt(1)
+	chainConfig.ByzantiumBlock = big.NewInt(2)
+	chainConfig.IstanbulBlock = big.NewInt(3)
+	chainConfig.BerlinBlock = big.NewInt(4)
+	chainConfig.CancunTime = getBlockTime(big.NewInt(5))
+
+	testCases := []struct {
+		name  string
+		block *big.Int
+	}{
+		{"homestead", chainConfig.HomesteadBlock},
+		{"byzantium", chainConfig.ByzantiumBlock},
+		{"istanbul", chainConfig.IstanbulBlock},
+		{"berlin", chainConfig.BerlinBlock},
+		{"cancun", new(big.Int).Add(chainConfig.BerlinBlock, big.NewInt(1))},
+	}
+
+	// custom precompile address used for test
+	contractAddress := common.HexToAddress("0x0400000000000000000000000000000000000000")
+
+	// ensure we are not being shadowed by a core preompile address
+	for _, tc := range testCases {
+		rules := chainConfig.Rules(tc.block, false, *getBlockTime(tc.block))
+
+		for _, precompileAddr := range ActivePrecompiles(rules) {
+			if precompileAddr == contractAddress {
+				t.Fatalf("expected precompile %s to not be returned in %s block", contractAddress, tc.name)
+			}
+		}
+	}
+
+	// register the precompile
+	module := modules.Module{
+		Address:  contractAddress,
+		Contract: new(mockStatefulPrecompiledContract),
+	}
+
+	// TODO: should we allow dynamic registration to update ActivePrecompiles?
+	// Or should we enforce registration only at init?
+	err := modules.RegisterModule(module)
+	require.NoError(t, err, "could not register precompile for test")
+
+	for _, tc := range testCases {
+		rules := chainConfig.Rules(tc.block, false, *getBlockTime(tc.block))
+
+		exists := false
+		for _, precompileAddr := range ActivePrecompiles(rules) {
+			if precompileAddr == contractAddress {
+				exists = true
+			}
+		}
+
+		assert.True(t, exists, "expected %s block to include active stateful precompile %s", tc.name, contractAddress)
+	}
+}