interop: fetch baseExecFee once and keep it in the Context

It never changes during single execution, so we can cache it and avoid going
to Policer via Chain for every instruction.

pkg/core/interop/context.go

@@ -48,14 +48,20 @@ type Context struct {
 	VM            *vm.VM
 	Functions     []Function
 	getContract   func(dao.DAO, util.Uint160) (*state.Contract, error)
+	baseExecFee   int64
 }
 
 // NewContext returns new interop context.
 func NewContext(trigger trigger.Type, bc blockchainer.Blockchainer, d dao.DAO,
 	getContract func(dao.DAO, util.Uint160) (*state.Contract, error), natives []Contract,
 	block *block.Block, tx *transaction.Transaction, log *zap.Logger) *Context {
+	baseExecFee := int64(DefaultBaseExecFee)
 	dao := d.GetWrapped()
 	nes := make([]state.NotificationEvent, 0)
+
+	if bc != nil && (block == nil || block.Index != 0) {
+		baseExecFee = bc.GetPolicer().GetBaseExecFee()
+	}
 	return &Context{
 		Chain:         bc,
 		Network:       uint32(bc.GetConfig().Magic),
@@ -69,6 +75,7 @@ func NewContext(trigger trigger.Type, bc blockchainer.Blockchainer, d dao.DAO,
 		// Functions is a slice of interops sorted by ID.
 		Functions:   []Function{},
 		getContract: getContract,
+		baseExecFee: baseExecFee,
 	}
 }
 
@@ -254,10 +261,7 @@ func (ic *Context) GetFunction(id uint32) *Function {
 
 // BaseExecFee represents factor to multiply syscall prices with.
 func (ic *Context) BaseExecFee() int64 {
-	if ic.Chain == nil || (ic.Block != nil && ic.Block.Index == 0) {
-		return DefaultBaseExecFee
-	}
-	return ic.Chain.GetPolicer().GetBaseExecFee()
+	return ic.baseExecFee
 }
 
 // SyscallHandler handles syscall with id.

pkg/core/interop/crypto/ecdsa_test.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"testing"
 
+	"github.com/nspcc-dev/neo-go/internal/fakechain"
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	"github.com/nspcc-dev/neo-go/pkg/core/dao"
 	"github.com/nspcc-dev/neo-go/pkg/core/fee"
@@ -67,12 +68,15 @@ func initCheckMultisigVMNoArgs(container *transaction.Transaction) *vm.VM {
 	buf[0] = byte(opcode.SYSCALL)
 	binary.LittleEndian.PutUint32(buf[1:], neoCryptoCheckMultisigID)
 
-	ic := &interop.Context{
-		Network:   uint32(netmode.UnitTestNet),
-		Trigger:   trigger.Verification,
-		Container: container,
-		Functions: Interops,
-	}
+	ic := interop.NewContext(
+		trigger.Verification,
+		fakechain.NewFakeChain(),
+		dao.NewSimple(storage.NewMemoryStore(), false),
+		nil, nil, nil,
+		container,
+		nil)
+	ic.Container = container
+	ic.Functions = Interops
 	v := ic.SpawnVM()
 	v.LoadScript(buf)
 	return v

pkg/core/interop/gas_price.go

@@ -7,5 +7,5 @@ import (
 
 // GetPrice returns a price for executing op with the provided parameter.
 func (ic *Context) GetPrice(op opcode.Opcode, parameter []byte) int64 {
-	return fee.Opcode(ic.BaseExecFee(), op)
+	return fee.Opcode(ic.baseExecFee, op)
 }