params: core, core/vm, miner: 64bit gas instructions

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

3 files changed, 11 insertions, 9 deletions

diff --git a/core/vm/runtime/env.go b/core/vm/runtime/env.go
index a25c6d71c..9aa88e669 100644
--- a/core/vm/runtime/env.go
+++ b/core/vm/runtime/env.go
@@ -36,7 +36,7 @@ func NewEnv(cfg *Config, state *state.StateDB) *vm.EVM {
 		BlockNumber: cfg.BlockNumber,
 		Time:        cfg.Time,
 		Difficulty:  cfg.Difficulty,
-		GasLimit:    cfg.GasLimit,
+		GasLimit:    new(big.Int).SetUint64(cfg.GasLimit),
 		GasPrice:    new(big.Int),
 	}
 
diff --git a/core/vm/runtime/runtime.go b/core/vm/runtime/runtime.go
index b5adb982c..cf46603db 100644
--- a/core/vm/runtime/runtime.go
+++ b/core/vm/runtime/runtime.go
@@ -17,6 +17,7 @@
 package runtime
 
 import (
+	"math"
 	"math/big"
 	"time"
 
@@ -37,7 +38,7 @@ type Config struct {
 	Coinbase    common.Address
 	BlockNumber *big.Int
 	Time        *big.Int
-	GasLimit    *big.Int
+	GasLimit    uint64
 	GasPrice    *big.Int
 	Value       *big.Int
 	DisableJit  bool // "disable" so it's enabled by default
@@ -68,8 +69,8 @@ func setDefaults(cfg *Config) {
 	if cfg.Time == nil {
 		cfg.Time = big.NewInt(time.Now().Unix())
 	}
-	if cfg.GasLimit == nil {
-		cfg.GasLimit = new(big.Int).Set(common.MaxBig)
+	if cfg.GasLimit == 0 {
+		cfg.GasLimit = math.MaxUint64
 	}
 	if cfg.GasPrice == nil {
 		cfg.GasPrice = new(big.Int)
@@ -112,7 +113,7 @@ func Execute(code, input []byte, cfg *Config) ([]byte, *state.StateDB, error) {
 	receiver.SetCode(crypto.Keccak256Hash(code), code)
 
 	// Call the code with the given configuration.
-	ret, err := vmenv.Call(
+	ret, _, err := vmenv.Call(
 		sender,
 		receiver.Address(),
 		input,
@@ -140,12 +141,13 @@ func Create(input []byte, cfg *Config) ([]byte, common.Address, error) {
 	)
 
 	// Call the code with the given configuration.
-	return vmenv.Create(
+	code, address, _, err := vmenv.Create(
 		sender,
 		input,
 		cfg.GasLimit,
 		cfg.Value,
 	)
+	return code, address, err
 }
 
 // Call executes the code given by the contract's address. It will return the
@@ -160,7 +162,7 @@ func Call(address common.Address, input []byte, cfg *Config) ([]byte, error) {
 
 	sender := cfg.State.GetOrNewStateObject(cfg.Origin)
 	// Call the code with the given configuration.
-	ret, err := vmenv.Call(
+	ret, _, err := vmenv.Call(
 		sender,
 		address,
 		input,
diff --git a/core/vm/runtime/runtime_test.go b/core/vm/runtime/runtime_test.go
index 1e618b688..8ad74a89a 100644
--- a/core/vm/runtime/runtime_test.go
+++ b/core/vm/runtime/runtime_test.go
@@ -39,8 +39,8 @@ func TestDefaults(t *testing.T) {
 	if cfg.Time == nil {
 		t.Error("expected time to be non nil")
 	}
-	if cfg.GasLimit == nil {
-		t.Error("expected time to be non nil")
+	if cfg.GasLimit == 0 {
+		t.Error("didn't expect gaslimit to be zero")
 	}
 	if cfg.GasPrice == nil {
 		t.Error("expected time to be non nil")