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Diffstat (limited to 'core/vm/interpreter.go')
-rw-r--r-- | core/vm/interpreter.go | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/core/vm/interpreter.go b/core/vm/interpreter.go new file mode 100644 index 000000000..ad41e3602 --- /dev/null +++ b/core/vm/interpreter.go @@ -0,0 +1,208 @@ +// 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/common/math" + "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 + intPool *intPool +} + +// 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), + intPool: newIntPool(), + } +} + +// 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 uint64 + ) + 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 { + // XXX For debugging + //fmt.Printf("%04d: %8v cost = %-8d stack = %-8d ERR = %v\n", pc, op, cost, stack.len(), err) + // TODO update the tracer + g, c := new(big.Int).SetUint64(contract.Gas), new(big.Int).SetUint64(cost) + evm.cfg.Tracer.CaptureState(evm.env, pc, op, g, c, 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 SUICIDE 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 uint64 + // calculate the new memory size and expand the memory to fit + // the operation + if operation.memorySize != nil { + memSize, overflow := bigUint64(operation.memorySize(stack)) + if overflow { + return nil, errGasUintOverflow + } + // memory is expanded in words of 32 bytes. Gas + // is also calculated in words. + if memorySize, overflow = math.SafeMul(toWordSize(memSize), 32); overflow { + return nil, errGasUintOverflow + } + } + + 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, err = operation.gasCost(evm.gasTable, evm.env, contract, stack, mem, memorySize) + if err != nil || !contract.UseGas(cost) { + return nil, ErrOutOfGas + } + } + if memorySize > 0 { + mem.Resize(memorySize) + } + + if evm.cfg.Debug { + g, c := new(big.Int).SetUint64(contract.Gas), new(big.Int).SetUint64(cost) + evm.cfg.Tracer.CaptureState(evm.env, pc, op, g, c, mem, stack, contract, evm.env.depth, err) + } + // XXX For debugging + //fmt.Printf("%04d: %8v cost = %-8d stack = %-8d\n", pc, op, cost, stack.len()) + + // execute the operation + res, err := operation.execute(&pc, evm.env, contract, mem, stack) + // verifyPool is a build flag. Pool verification makes sure the integrity + // of the integer pool by comparing values to a default value. + if verifyPool { + verifyIntegerPool(evm.intPool) + } + switch { + case err != nil: + return nil, err + case operation.halts: + return res, nil + case !operation.jumps: + pc++ + } + } + return nil, nil +} |