core/vm: added JIT segmenting / optimisations

* multi-push segments
* static jumps segments

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}
+}