diff options
Diffstat (limited to 'core/vm/jit_optimiser.go')
-rw-r--r-- | core/vm/jit_optimiser.go | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/core/vm/jit_optimiser.go b/core/vm/jit_optimiser.go new file mode 100644 index 000000000..4823cc1a0 --- /dev/null +++ b/core/vm/jit_optimiser.go @@ -0,0 +1,90 @@ +package vm + +import ( + "math/big" + "time" + + "github.com/ethereum/go-ethereum/logger" + "github.com/ethereum/go-ethereum/logger/glog" +) + +// optimeProgram optimises a JIT program creating segments out of program +// instructions. Currently covered are multi-pushes and static jumps +func optimiseProgram(program *Program) { + var load []instruction + + var ( + statsJump = 0 + statsPush = 0 + ) + + if glog.V(logger.Debug) { + glog.Infof("optimising %x\n", program.Id[:4]) + tstart := time.Now() + defer func() { + glog.Infof("optimised %x done in %v with JMP: %d PSH: %d\n", program.Id[:4], time.Since(tstart), statsJump, statsPush) + }() + } + + for i := 0; i < len(program.instructions); i++ { + instr := program.instructions[i].(instruction) + + switch { + case instr.op.IsPush(): + load = append(load, instr) + case instr.op.IsStaticJump(): + if len(load) == 0 { + continue + } + // if the push load is greater than 1, finalise that + // segment first + if len(load) > 2 { + seg, size := makePushSeg(load[:len(load)-1]) + program.instructions[i-size-1] = seg + statsPush++ + } + // create a segment consisting of a pre determined + // jump, destination and validity. + seg := makeStaticJumpSeg(load[len(load)-1].data, program) + program.instructions[i-1] = seg + statsJump++ + + load = nil + default: + // create a new N pushes segment + if len(load) > 1 { + seg, size := makePushSeg(load) + program.instructions[i-size] = seg + statsPush++ + } + load = nil + } + } +} + +// makePushSeg creates a new push segment from N amount of push instructions +func makePushSeg(instrs []instruction) (pushSeg, int) { + var ( + data []*big.Int + gas = new(big.Int) + ) + + for _, instr := range instrs { + data = append(data, instr.data) + gas.Add(gas, instr.gas) + } + + return pushSeg{data, gas}, len(instrs) +} + +// makeStaticJumpSeg creates a new static jump segment from a predefined +// destination (PUSH, JUMP). +func makeStaticJumpSeg(to *big.Int, program *Program) jumpSeg { + gas := new(big.Int) + gas.Add(gas, _baseCheck[PUSH1].gas) + gas.Add(gas, _baseCheck[JUMP].gas) + + contract := &Contract{Code: program.code} + pos, err := jump(program.mapping, program.destinations, contract, to) + return jumpSeg{pos, err, gas} +} |