1 files changed, 188 insertions, 0 deletions
diff --git a/core/vm/vm.go b/core/vm/vm.go
new file mode 100644
index 000000000..05886a863
--- /dev/null
+++ b/core/vm/vm.go
@@ -0,0 +1,188 @@
+// Copyright 2014 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package vm
+
+import (
+	"fmt"
+	"math/big"
+	"sync/atomic"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/logger"
+	"github.com/ethereum/go-ethereum/logger/glog"
+	"github.com/ethereum/go-ethereum/params"
+)
+
+// Config are the configuration options for the Interpreter
+type Config struct {
+	// Debug enabled debugging Interpreter options
+	Debug bool
+	// EnableJit enabled the JIT VM
+	EnableJit bool
+	// ForceJit forces the JIT VM
+	ForceJit bool
+	// Tracer is the op code logger
+	Tracer Tracer
+	// NoRecursion disabled Interpreter call, callcode,
+	// delegate call and create.
+	NoRecursion bool
+	// Disable gas metering
+	DisableGasMetering bool
+	// Enable recording of SHA3/keccak preimages
+	EnablePreimageRecording bool
+	// JumpTable contains the EVM instruction table. This
+	// may me left uninitialised and will be set the default
+	// table.
+	JumpTable [256]operation
+}
+
+// Interpreter is used to run Ethereum based contracts and will utilise the
+// passed environment to query external sources for state information.
+// The Interpreter will run the byte code VM or JIT VM based on the passed
+// configuration.
+type Interpreter struct {
+	env      *EVM
+	cfg      Config
+	gasTable params.GasTable
+}
+
+// NewInterpreter returns a new instance of the Interpreter.
+func NewInterpreter(env *EVM, cfg Config) *Interpreter {
+	// We use the STOP instruction whether to see
+	// the jump table was initialised. If it was not
+	// we'll set the default jump table.
+	if !cfg.JumpTable[STOP].valid {
+		cfg.JumpTable = defaultJumpTable
+	}
+
+	return &Interpreter{
+		env:      env,
+		cfg:      cfg,
+		gasTable: env.ChainConfig().GasTable(env.BlockNumber),
+	}
+}
+
+// Run loops and evaluates the contract's code with the given input data
+func (evm *Interpreter) Run(contract *Contract, input []byte) (ret []byte, err error) {
+	evm.env.depth++
+	defer func() { evm.env.depth-- }()
+
+	if contract.CodeAddr != nil {
+		if p := PrecompiledContracts[*contract.CodeAddr]; p != nil {
+			return RunPrecompiledContract(p, input, contract)
+		}
+	}
+
+	// Don't bother with the execution if there's no code.
+	if len(contract.Code) == 0 {
+		return nil, nil
+	}
+
+	codehash := contract.CodeHash // codehash is used when doing jump dest caching
+	if codehash == (common.Hash{}) {
+		codehash = crypto.Keccak256Hash(contract.Code)
+	}
+
+	var (
+		op    OpCode        // current opcode
+		mem   = NewMemory() // bound memory
+		stack = newstack()  // local stack
+		// For optimisation reason we're using uint64 as the program counter.
+		// It's theoretically possible to go above 2^64. The YP defines the PC to be uint256. Practically much less so feasible.
+		pc   = uint64(0) // program counter
+		cost *big.Int
+	)
+	contract.Input = input
+
+	// User defer pattern to check for an error and, based on the error being nil or not, use all gas and return.
+	defer func() {
+		if err != nil && evm.cfg.Debug {
+			evm.cfg.Tracer.CaptureState(evm.env, pc, op, contract.Gas, cost, mem, stack, contract, evm.env.depth, err)
+		}
+	}()
+
+	if glog.V(logger.Debug) {
+		glog.Infof("evm running: %x\n", codehash[:4])
+		tstart := time.Now()
+		defer func() {
+			glog.Infof("evm done: %x. time: %v\n", codehash[:4], time.Since(tstart))
+		}()
+	}
+
+	// The Interpreter main run loop (contextual). This loop runs until either an
+	// explicit STOP, RETURN or SELFDESTRUCT is executed, an error occurred during
+	// the execution of one of the operations or until the evm.done is set by
+	// the parent context.Context.
+	for atomic.LoadInt32(&evm.env.abort) == 0 {
+		// Get the memory location of pc
+		op = contract.GetOp(pc)
+
+		// get the operation from the jump table matching the opcode
+		operation := evm.cfg.JumpTable[op]
+
+		// if the op is invalid abort the process and return an error
+		if !operation.valid {
+			return nil, fmt.Errorf("invalid opcode %x", op)
+		}
+
+		// validate the stack and make sure there enough stack items available
+		// to perform the operation
+		if err := operation.validateStack(stack); err != nil {
+			return nil, err
+		}
+
+		var memorySize *big.Int
+		// calculate the new memory size and expand the memory to fit
+		// the operation
+		if operation.memorySize != nil {
+			memorySize = operation.memorySize(stack)
+			// memory is expanded in words of 32 bytes. Gas
+			// is also calculated in words.
+			memorySize.Mul(toWordSize(memorySize), big.NewInt(32))
+		}
+
+		if !evm.cfg.DisableGasMetering {
+			// consume the gas and return an error if not enough gas is available.
+			// cost is explicitly set so that the capture state defer method cas get the proper cost
+			cost = operation.gasCost(evm.gasTable, evm.env, contract, stack, mem, memorySize)
+			if !contract.UseGas(cost) {
+				return nil, ErrOutOfGas
+			}
+		}
+		if memorySize != nil {
+			mem.Resize(memorySize.Uint64())
+		}
+
+		if evm.cfg.Debug {
+			evm.cfg.Tracer.CaptureState(evm.env, pc, op, contract.Gas, cost, mem, stack, contract, evm.env.depth, err)
+		}
+
+		// execute the operation
+		res, err := operation.execute(&pc, evm.env, contract, mem, stack)
+		switch {
+		case err != nil:
+			return nil, err
+		case operation.halts:
+			return res, nil
+		case !operation.jumps:
+			pc++
+		}
+	}
+	return nil, nil
+}