108 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			108 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
| package vm
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| 
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| import (
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| 	"math/big"
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| 	"time"
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| 
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| 	"github.com/ethereum/go-ethereum/logger"
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| 	"github.com/ethereum/go-ethereum/logger/glog"
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| )
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| 
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| // optimeProgram optimises a JIT program creating segments out of program
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| // instructions. Currently covered are multi-pushes and static jumps
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| func optimiseProgram(program *Program) {
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| 	var load []instruction
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| 
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| 	var (
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| 		statsJump = 0
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| 		statsPush = 0
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| 	)
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| 
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| 	if glog.V(logger.Debug) {
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| 		glog.Infof("optimising %x\n", program.Id[:4])
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| 		tstart := time.Now()
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| 		defer func() {
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| 			glog.Infof("optimised %x done in %v with JMP: %d PSH: %d\n", program.Id[:4], time.Since(tstart), statsJump, statsPush)
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| 		}()
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| 	}
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| 
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| 	/*
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| 		code := Parse(program.code)
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| 		for _, test := range [][]OpCode{
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| 			[]OpCode{PUSH, PUSH, ADD},
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| 			[]OpCode{PUSH, PUSH, SUB},
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| 			[]OpCode{PUSH, PUSH, MUL},
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| 			[]OpCode{PUSH, PUSH, DIV},
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| 		} {
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| 			matchCount := 0
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| 			MatchFn(code, test, func(i int) bool {
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| 				matchCount++
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| 				return true
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| 			})
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| 			fmt.Printf("found %d match count on: %v\n", matchCount, test)
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| 		}
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| 	*/
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| 
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| 	for i := 0; i < len(program.instructions); i++ {
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| 		instr := program.instructions[i].(instruction)
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| 
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| 		switch {
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| 		case instr.op.IsPush():
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| 			load = append(load, instr)
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| 		case instr.op.IsStaticJump():
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| 			if len(load) == 0 {
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| 				continue
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| 			}
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| 			// if the push load is greater than 1, finalise that
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| 			// segment first
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| 			if len(load) > 2 {
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| 				seg, size := makePushSeg(load[:len(load)-1])
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| 				program.instructions[i-size-1] = seg
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| 				statsPush++
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| 			}
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| 			// create a segment consisting of a pre determined
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| 			// jump, destination and validity.
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| 			seg := makeStaticJumpSeg(load[len(load)-1].data, program)
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| 			program.instructions[i-1] = seg
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| 			statsJump++
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| 
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| 			load = nil
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| 		default:
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| 			// create a new N pushes segment
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| 			if len(load) > 1 {
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| 				seg, size := makePushSeg(load)
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| 				program.instructions[i-size] = seg
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| 				statsPush++
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| 			}
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| 			load = nil
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| 		}
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| 	}
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| }
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| 
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| // makePushSeg creates a new push segment from N amount of push instructions
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| func makePushSeg(instrs []instruction) (pushSeg, int) {
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| 	var (
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| 		data []*big.Int
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| 		gas  = new(big.Int)
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| 	)
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| 
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| 	for _, instr := range instrs {
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| 		data = append(data, instr.data)
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| 		gas.Add(gas, instr.gas)
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| 	}
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| 
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| 	return pushSeg{data, gas}, len(instrs)
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| }
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| 
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| // makeStaticJumpSeg creates a new static jump segment from a predefined
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| // destination (PUSH, JUMP).
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| func makeStaticJumpSeg(to *big.Int, program *Program) jumpSeg {
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| 	gas := new(big.Int)
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| 	gas.Add(gas, _baseCheck[PUSH1].gas)
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| 	gas.Add(gas, _baseCheck[JUMP].gas)
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| 
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| 	contract := &Contract{Code: program.code}
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| 	pos, err := jump(program.mapping, program.destinations, contract, to)
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| 	return jumpSeg{pos, err, gas}
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| }
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