core: vm: refactor vm config and context

To support multiple VMs, there must be a shared execution environment for each VM,
so this pull request moved some shared component to vm.Context and
implemented the vm.ExecPack to hold the list of VM, list of VM configures,
context and some shared resources.

The adjustment includes:
* Move NoRecursion, Depth, ReadOnly, RandCallIndex, IntPool and CallGasTemp to Context.
* Adjust VM enumeration from byte to uint8, and the VMList from map to
array.
* Register VM constructor in each VM package's init function.
* Initialize all VM instance in NewExecPack.
* Remove EVMImplement, and modify EVM, such that EVM can do the same
functions with EVMImplement.

3 files changed, 21 insertions, 9 deletions

diff --git a/light/odr_test.go b/light/odr_test.go
index 267d1a346..f5020dfa7 100644
--- a/light/odr_test.go
+++ b/light/odr_test.go
@@ -31,7 +31,8 @@ import (
 	"github.com/dexon-foundation/dexon/core/rawdb"
 	"github.com/dexon-foundation/dexon/core/state"
 	"github.com/dexon-foundation/dexon/core/types"
-	vm "github.com/dexon-foundation/dexon/core/vm/evm"
+	"github.com/dexon-foundation/dexon/core/vm"
+	"github.com/dexon-foundation/dexon/core/vm/evm"
 	"github.com/dexon-foundation/dexon/core/vm/tools"
 	"github.com/dexon-foundation/dexon/crypto"
 	"github.com/dexon-foundation/dexon/ethdb"
@@ -196,10 +197,12 @@ func odrContractCall(ctx context.Context, db ethdb.Database, bc *core.BlockChain
 		// Perform read-only call.
 		st.SetBalance(testBankAddress, math.MaxBig256)
 		msg := callmsg{types.NewMessage(testBankAddress, &testContractAddr, 0, new(big.Int), 1000000, new(big.Int), data, false)}
-		context := core.NewEVMContext(msg, header, chain, nil)
-		vmenv := vm.NewEVM(context, st, config, vm.Config{})
+		context := core.NewVMContext(msg, header, chain, nil)
+		vmConfig := [vm.NUMS]interface{}{}
+		vmConfig[vm.EVM] = evm.Config{}
+		pack := vm.NewExecPack(context, st, config, vmConfig)
 		gp := new(core.GasPool).AddGas(math.MaxUint64)
-		ret, _, _, _ := core.ApplyMessage(vmenv, msg, gp)
+		ret, _, _, _ := core.ApplyMessage(&pack, msg, gp)
 		res = append(res, ret...)
 		if st.Error() != nil {
 			return res, st.Error()
@@ -259,7 +262,9 @@ func testChainOdr(t *testing.T, protocol int, fn odrTestFn) {
 	)
 	gspec.MustCommit(ldb)
 	// Assemble the test environment
-	blockchain, _ := core.NewBlockChain(sdb, nil, params.TestChainConfig, ethash.NewFullFaker(), vm.Config{}, nil)
+	vmConfig := [vm.NUMS]interface{}{}
+	vmConfig[vm.EVM] = evm.Config{}
+	blockchain, _ := core.NewBlockChain(sdb, nil, params.TestChainConfig, ethash.NewFullFaker(), vmConfig, nil)
 	gchain, _ := core.GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), sdb, 4, testChainGen)
 	if _, err := blockchain.InsertChain(gchain); err != nil {
 		t.Fatal(err)
diff --git a/light/trie_test.go b/light/trie_test.go
index 72b709ea6..18324f2b9 100644
--- a/light/trie_test.go
+++ b/light/trie_test.go
@@ -26,7 +26,8 @@ import (
 	"github.com/dexon-foundation/dexon/consensus/ethash"
 	"github.com/dexon-foundation/dexon/core"
 	"github.com/dexon-foundation/dexon/core/state"
-	vm "github.com/dexon-foundation/dexon/core/vm/evm"
+	"github.com/dexon-foundation/dexon/core/vm"
+	"github.com/dexon-foundation/dexon/core/vm/evm"
 	"github.com/dexon-foundation/dexon/ethdb"
 	"github.com/dexon-foundation/dexon/params"
 	"github.com/dexon-foundation/dexon/trie"
@@ -40,7 +41,9 @@ func TestNodeIterator(t *testing.T) {
 		genesis = gspec.MustCommit(fulldb)
 	)
 	gspec.MustCommit(lightdb)
-	blockchain, _ := core.NewBlockChain(fulldb, nil, params.TestChainConfig, ethash.NewFullFaker(), vm.Config{}, nil)
+	vmConfig := [vm.NUMS]interface{}{}
+	vmConfig[vm.EVM] = evm.Config{}
+	blockchain, _ := core.NewBlockChain(fulldb, nil, params.TestChainConfig, ethash.NewFullFaker(), vmConfig, nil)
 	gchain, _ := core.GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), fulldb, 4, testChainGen)
 	if _, err := blockchain.InsertChain(gchain); err != nil {
 		panic(err)
diff --git a/light/txpool_test.go b/light/txpool_test.go
index 4775261d9..c875ff2fa 100644
--- a/light/txpool_test.go
+++ b/light/txpool_test.go
@@ -27,7 +27,8 @@ import (
 	"github.com/dexon-foundation/dexon/consensus/ethash"
 	"github.com/dexon-foundation/dexon/core"
 	"github.com/dexon-foundation/dexon/core/types"
-	vm "github.com/dexon-foundation/dexon/core/vm/evm"
+	"github.com/dexon-foundation/dexon/core/vm"
+	"github.com/dexon-foundation/dexon/core/vm/evm"
 	"github.com/dexon-foundation/dexon/ethdb"
 	"github.com/dexon-foundation/dexon/params"
 )
@@ -88,7 +89,10 @@ func TestTxPool(t *testing.T) {
 	)
 	gspec.MustCommit(ldb)
 	// Assemble the test environment
-	blockchain, _ := core.NewBlockChain(sdb, nil, params.TestChainConfig, ethash.NewFullFaker(), vm.Config{}, nil)
+
+	vmConfig := [vm.NUMS]interface{}{}
+	vmConfig[vm.EVM] = evm.Config{}
+	blockchain, _ := core.NewBlockChain(sdb, nil, params.TestChainConfig, ethash.NewFullFaker(), vmConfig, nil)
 	gchain, _ := core.GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), sdb, poolTestBlocks, txPoolTestChainGen)
 	if _, err := blockchain.InsertChain(gchain); err != nil {
 		panic(err)