params: core, core/vm, miner: 64bit gas instructions (#3514)

Reworked the EVM gas instructions to use 64bit integers rather than
arbitrary size big ints. All gas operations, be it additions,
multiplications or divisions, are checked and guarded against 64 bit
integer overflows.

In additon, most of the protocol paramaters in the params package have
been converted to uint64 and are now constants rather than variables.

* common/math: added overflow check ops
* core: vmenv, env renamed to evm
* eth, internal/ethapi, les: unmetered eth_call and cancel methods
* core/vm: implemented big.Int pool for evm instructions
* core/vm: unexported intPool methods & verification methods
* core/vm: added memoryGasCost overflow check and test

2 files changed, 7 insertions, 5 deletions

diff --git a/les/api_backend.go b/les/api_backend.go
index 3a71ac4e0..ed2a7cd13 100644
--- a/les/api_backend.go
+++ b/les/api_backend.go
@@ -88,7 +88,7 @@ func (b *LesApiBackend) GetTd(blockHash common.Hash) *big.Int {
 	return b.eth.blockchain.GetTdByHash(blockHash)
 }
 
-func (b *LesApiBackend) GetVMEnv(ctx context.Context, msg core.Message, state ethapi.State, header *types.Header) (*vm.EVM, func() error, error) {
+func (b *LesApiBackend) GetEVM(ctx context.Context, msg core.Message, state ethapi.State, header *types.Header, vmCfg vm.Config) (*vm.EVM, func() error, error) {
 	stateDb := state.(*light.LightState).Copy()
 	addr := msg.From()
 	from, err := stateDb.GetOrNewStateObject(ctx, addr)
@@ -99,7 +99,7 @@ func (b *LesApiBackend) GetVMEnv(ctx context.Context, msg core.Message, state et
 
 	vmstate := light.NewVMState(ctx, stateDb)
 	context := core.NewEVMContext(msg, header, b.eth.blockchain)
-	return vm.NewEVM(context, vmstate, b.eth.chainConfig, vm.Config{}), vmstate.Error, nil
+	return vm.NewEVM(context, vmstate, b.eth.chainConfig, vmCfg), vmstate.Error, nil
 }
 
 func (b *LesApiBackend) SendTx(ctx context.Context, signedTx *types.Transaction) error {
diff --git a/les/helper_test.go b/les/helper_test.go
index e0b7558ee..2c6f34a92 100644
--- a/les/helper_test.go
+++ b/les/helper_test.go
@@ -57,6 +57,8 @@ var (
 	testContractDeployed     = uint64(2)
 
 	testBufLimit = uint64(100)
+
+	bigTxGas = new(big.Int).SetUint64(params.TxGas)
 )
 
 /*
@@ -80,15 +82,15 @@ func testChainGen(i int, block *core.BlockGen) {
 	switch i {
 	case 0:
 		// In block 1, the test bank sends account #1 some ether.
-		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), acc1Addr, big.NewInt(10000), params.TxGas, nil, nil), signer, testBankKey)
+		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), acc1Addr, big.NewInt(10000), bigTxGas, nil, nil), signer, testBankKey)
 		block.AddTx(tx)
 	case 1:
 		// In block 2, the test bank sends some more ether to account #1.
 		// acc1Addr passes it on to account #2.
 		// acc1Addr creates a test contract.
-		tx1, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), acc1Addr, big.NewInt(1000), params.TxGas, nil, nil), signer, testBankKey)
+		tx1, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), acc1Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, testBankKey)
 		nonce := block.TxNonce(acc1Addr)
-		tx2, _ := types.SignTx(types.NewTransaction(nonce, acc2Addr, big.NewInt(1000), params.TxGas, nil, nil), signer, acc1Key)
+		tx2, _ := types.SignTx(types.NewTransaction(nonce, acc2Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, acc1Key)
 		nonce++
 		tx3, _ := types.SignTx(types.NewContractCreation(nonce, big.NewInt(0), big.NewInt(200000), big.NewInt(0), testContractCode), signer, acc1Key)
 		testContractAddr = crypto.CreateAddress(acc1Addr, nonce)