package dotty.tools.backend.jvm
import scala.tools.asm
import asm._
import asm.tree._
import scala.collection.JavaConverters._
/** Makes using ASM from tests more convenient.
*
* Wraps ASM instructions in case classes so that equals and toString work
* for the purpose of bytecode diffing and pretty printing.
*/
object ASMConverters {
import asm.{tree => t}
/**
* Transform the instructions of an ASM Method into a list of [[Instruction]]s.
*/
def instructionsFromMethod(meth: t.MethodNode): List[Instruction] = new AsmToScala(meth).instructions
def convertMethod(meth: t.MethodNode): Method = new AsmToScala(meth).method
implicit class RichInstructionLists(val self: List[Instruction]) extends AnyVal {
def === (other: List[Instruction]) = equivalentBytecode(self, other)
def dropLinesFrames = self.filterNot(i => i.isInstanceOf[LineNumber] || i.isInstanceOf[FrameEntry])
private def referencedLabels(instruction: Instruction): Set[Instruction] = instruction match {
case Jump(op, label) => Set(label)
case LookupSwitch(op, dflt, keys, labels) => (dflt :: labels).toSet
case TableSwitch(op, min, max, dflt, labels) => (dflt :: labels).toSet
case LineNumber(line, start) => Set(start)
case _ => Set.empty
}
def dropStaleLabels = {
val definedLabels: Set[Instruction] = self.filter(_.isInstanceOf[Label]).toSet
val usedLabels: Set[Instruction] = self.flatMap(referencedLabels)(collection.breakOut)
self.filterNot(definedLabels diff usedLabels)
}
def dropNonOp = dropLinesFrames.dropStaleLabels
def summary: List[Any] = dropNonOp map {
case i: Invoke => i.name
case i => i.opcode
}
def summaryText: String = {
def comment(i: Instruction) = i match {
case j: Jump => s" /*${j.label.offset}*/"
case l: Label => s" /*${l.offset}*/"
case _ => ""
}
dropNonOp.map({
case i: Invoke => s""""${i.name}""""
case ins => opcodeToString(ins.opcode, ins.opcode) + comment(ins)
}).mkString("List(", ", ", ")")
}
}
def opcodeToString(op: Int, default: Any = "?"): String = {
import scala.tools.asm.util.Printer.OPCODES
if (OPCODES.isDefinedAt(op)) OPCODES(op) else default.toString
}
sealed abstract class Instruction extends Product {
def opcode: Int
// toString such that the first field, "opcode: Int", is printed textually.
final override def toString() = {
val printOpcode = opcode != -1
productPrefix + (
if (printOpcode) Iterator(opcodeToString(opcode)) ++ productIterator.drop(1)
else productIterator
).mkString("(", ", ", ")")
}
}
case class Method(instructions: List[Instruction], handlers: List[ExceptionHandler], localVars: List[LocalVariable])
case class Field (opcode: Int, owner: String, name: String, desc: String) extends Instruction
case class Incr (opcode: Int, `var`: Int, incr: Int) extends Instruction
case class Op (opcode: Int) extends Instruction
case class IntOp (opcode: Int, operand: Int) extends Instruction
case class Jump (opcode: Int, label: Label) extends Instruction
case class Ldc (opcode: Int, cst: Any) extends Instruction
case class LookupSwitch (opcode: Int, dflt: Label, keys: List[Int], labels: List[Label]) extends Instruction
case class TableSwitch (opcode: Int, min: Int, max: Int, dflt: Label, labels: List[Label]) extends Instruction
case class Invoke (opcode: Int, owner: String, name: String, desc: String, itf: Boolean) extends Instruction
case class InvokeDynamic(opcode: Int, name: String, desc: String, bsm: MethodHandle, bsmArgs: List[AnyRef]) extends Instruction
case class NewArray (opcode: Int, desc: String, dims: Int) extends Instruction
case class TypeOp (opcode: Int, desc: String) extends Instruction
case class VarOp (opcode: Int, `var`: Int) extends Instruction
case class Label (offset: Int) extends Instruction { def opcode: Int = -1 }
case class FrameEntry (`type`: Int, local: List[Any], stack: List[Any]) extends Instruction { def opcode: Int = -1 }
case class LineNumber (line: Int, start: Label) extends Instruction { def opcode: Int = -1 }
case class MethodHandle(tag: Int, owner: String, name: String, desc: String)
case class ExceptionHandler(start: Label, end: Label, handler: Label, desc: Option[String])
case class LocalVariable(name: String, desc: String, signature: Option[String], start: Label, end: Label, index: Int)
class AsmToScala(asmMethod: t.MethodNode) {
def instructions: List[Instruction] = asmMethod.instructions.iterator.asScala.toList map apply
def method: Method = Method(instructions, convertHandlers(asmMethod), convertLocalVars(asmMethod))
private def labelIndex(l: t.LabelNode): Int = asmMethod.instructions.indexOf(l)
private def op(i: t.AbstractInsnNode): Int = i.getOpcode
private def lst[T](xs: java.util.List[T]): List[T] = if (xs == null) Nil else xs.asScala.toList
// Heterogeneous List[Any] is used in FrameNode: type information about locals / stack values
// are stored in a List[Any] (Integer, String or LabelNode), see Javadoc of MethodNode#visitFrame.
// Opcodes (eg Opcodes.INTEGER) and Reference types (eg "java/lang/Object") are returned unchanged,
// LabelNodes are mapped to their LabelEntry.
private def mapOverFrameTypes(is: List[Any]): List[Any] = is map {
case i: t.LabelNode => applyLabel(i)
case x => x
}
// avoids some casts
private def applyLabel(l: t.LabelNode) = this(l: t.AbstractInsnNode).asInstanceOf[Label]
private def apply(x: t.AbstractInsnNode): Instruction = x match {
case i: t.FieldInsnNode => Field (op(i), i.owner, i.name, i.desc)
case i: t.IincInsnNode => Incr (op(i), i.`var`, i.incr)
case i: t.InsnNode => Op (op(i))
case i: t.IntInsnNode => IntOp (op(i), i.operand)
case i: t.JumpInsnNode => Jump (op(i), applyLabel(i.label))
case i: t.LdcInsnNode => Ldc (op(i), i.cst: Any)
case i: t.LookupSwitchInsnNode => LookupSwitch (op(i), applyLabel(i.dflt), lst(i.keys) map (x => x: Int), lst(i.labels) map applyLabel)
case i: t.TableSwitchInsnNode => TableSwitch (op(i), i.min, i.max, applyLabel(i.dflt), lst(i.labels) map applyLabel)
case i: t.MethodInsnNode => Invoke (op(i), i.owner, i.name, i.desc, i.itf)
case i: t.InvokeDynamicInsnNode => InvokeDynamic(op(i), i.name, i.desc, convertMethodHandle(i.bsm), convertBsmArgs(i.bsmArgs))
case i: t.MultiANewArrayInsnNode => NewArray (op(i), i.desc, i.dims)
case i: t.TypeInsnNode => TypeOp (op(i), i.desc)
case i: t.VarInsnNode => VarOp (op(i), i.`var`)
case i: t.LabelNode => Label (labelIndex(i))
case i: t.FrameNode => FrameEntry (i.`type`, mapOverFrameTypes(lst(i.local)), mapOverFrameTypes(lst(i.stack)))
case i: t.LineNumberNode => LineNumber (i.line, applyLabel(i.start))
}
private def convertBsmArgs(a: Array[Object]): List[Object] = a.map({
case h: asm.Handle => convertMethodHandle(h)
case _ => a // can be: Class, method Type, primitive constant
})(collection.breakOut)
private def convertMethodHandle(h: asm.Handle): MethodHandle = MethodHandle(h.getTag, h.getOwner, h.getName, h.getDesc)
private def convertHandlers(method: t.MethodNode): List[ExceptionHandler] = {
method.tryCatchBlocks.asScala.map(h => ExceptionHandler(applyLabel(h.start), applyLabel(h.end), applyLabel(h.handler), Option(h.`type`)))(collection.breakOut)
}
private def convertLocalVars(method: t.MethodNode): List[LocalVariable] = {
method.localVariables.asScala.map(v => LocalVariable(v.name, v.desc, Option(v.signature), applyLabel(v.start), applyLabel(v.end), v.index))(collection.breakOut)
}
}
import collection.mutable.{Map => MMap}
/**
* Bytecode is equal modulo local variable numbering and label numbering.
*/
def equivalentBytecode(as: List[Instruction], bs: List[Instruction], varMap: MMap[Int, Int] = MMap(), labelMap: MMap[Int, Int] = MMap()): Boolean = {
def same(v1: Int, v2: Int, m: MMap[Int, Int]) = {
if (m contains v1) m(v1) == v2
else if (m.valuesIterator contains v2) false // v2 is already associated with some different value v1
else { m(v1) = v2; true }
}
def sameVar(v1: Int, v2: Int) = same(v1, v2, varMap)
def sameLabel(l1: Label, l2: Label) = same(l1.offset, l2.offset, labelMap)
def sameLabels(ls1: List[Label], ls2: List[Label]) = (ls1 corresponds ls2)(sameLabel)
def sameFrameTypes(ts1: List[Any], ts2: List[Any]) = (ts1 corresponds ts2) {
case (t1: Label, t2: Label) => sameLabel(t1, t2)
case (x, y) => x == y
}
if (as.isEmpty) bs.isEmpty
else if (bs.isEmpty) false
else ((as.head, bs.head) match {
case (VarOp(op1, v1), VarOp(op2, v2)) => op1 == op2 && sameVar(v1, v2)
case (Incr(op1, v1, inc1), Incr(op2, v2, inc2)) => op1 == op2 && sameVar(v1, v2) && inc1 == inc2
case (l1 @ Label(_), l2 @ Label(_)) => sameLabel(l1, l2)
case (Jump(op1, l1), Jump(op2, l2)) => op1 == op2 && sameLabel(l1, l2)
case (LookupSwitch(op1, l1, keys1, ls1), LookupSwitch(op2, l2, keys2, ls2)) => op1 == op2 && sameLabel(l1, l2) && keys1 == keys2 && sameLabels(ls1, ls2)
case (TableSwitch(op1, min1, max1, l1, ls1), TableSwitch(op2, min2, max2, l2, ls2)) => op1 == op2 && min1 == min2 && max1 == max2 && sameLabel(l1, l2) && sameLabels(ls1, ls2)
case (LineNumber(line1, l1), LineNumber(line2, l2)) => line1 == line2 && sameLabel(l1, l2)
case (FrameEntry(tp1, loc1, stk1), FrameEntry(tp2, loc2, stk2)) => tp1 == tp2 && sameFrameTypes(loc1, loc2) && sameFrameTypes(stk1, stk2)
// this needs to go after the above. For example, Label(1) may not equal Label(1), if before
// the left 1 was associated with another right index.
case (a, b) if a == b => true
case _ => false
}) && equivalentBytecode(as.tail, bs.tail, varMap, labelMap)
}
def applyToMethod(method: t.MethodNode, instructions: List[Instruction]): Unit = {
val asmLabel = createLabelNodes(instructions)
instructions.foreach(visitMethod(method, _, asmLabel))
}
/**
* Convert back a [[Method]] to ASM land. The code is emitted into the parameter `asmMethod`.
*/
def applyToMethod(asmMethod: t.MethodNode, method: Method): Unit = {
val asmLabel = createLabelNodes(method.instructions)
method.instructions.foreach(visitMethod(asmMethod, _, asmLabel))
method.handlers.foreach(h => asmMethod.visitTryCatchBlock(asmLabel(h.start), asmLabel(h.end), asmLabel(h.handler), h.desc.orNull))
method.localVars.foreach(v => asmMethod.visitLocalVariable(v.name, v.desc, v.signature.orNull, asmLabel(v.start), asmLabel(v.end), v.index))
}
private def createLabelNodes(instructions: List[Instruction]): Map[Label, asm.Label] = {
val labels = instructions collect {
case l: Label => l
}
assert(labels.distinct == labels, s"Duplicate labels in: $labels")
labels.map(l => (l, new asm.Label())).toMap
}
private def frameTypesToAsm(l: List[Any], asmLabel: Map[Label, asm.Label]): List[Object] = l map {
case l: Label => asmLabel(l)
case x => x.asInstanceOf[Object]
}
def unconvertMethodHandle(h: MethodHandle): asm.Handle = new asm.Handle(h.tag, h.owner, h.name, h.desc)
def unconvertBsmArgs(a: List[Object]): Array[Object] = a.map({
case h: MethodHandle => unconvertMethodHandle(h)
case o => o
})(collection.breakOut)
private def visitMethod(method: t.MethodNode, instruction: Instruction, asmLabel: Map[Label, asm.Label]): Unit = instruction match {
case Field(op, owner, name, desc) => method.visitFieldInsn(op, owner, name, desc)
case Incr(op, vr, incr) => method.visitIincInsn(vr, incr)
case Op(op) => method.visitInsn(op)
case IntOp(op, operand) => method.visitIntInsn(op, operand)
case Jump(op, label) => method.visitJumpInsn(op, asmLabel(label))
case Ldc(op, cst) => method.visitLdcInsn(cst)
case LookupSwitch(op, dflt, keys, labels) => method.visitLookupSwitchInsn(asmLabel(dflt), keys.toArray, (labels map asmLabel).toArray)
case TableSwitch(op, min, max, dflt, labels) => method.visitTableSwitchInsn(min, max, asmLabel(dflt), (labels map asmLabel).toArray: _*)
case Invoke(op, owner, name, desc, itf) => method.visitMethodInsn(op, owner, name, desc, itf)
case InvokeDynamic(op, name, desc, bsm, bsmArgs) => method.visitInvokeDynamicInsn(name, desc, unconvertMethodHandle(bsm), unconvertBsmArgs(bsmArgs))
case NewArray(op, desc, dims) => method.visitMultiANewArrayInsn(desc, dims)
case TypeOp(op, desc) => method.visitTypeInsn(op, desc)
case VarOp(op, vr) => method.visitVarInsn(op, vr)
case l: Label => method.visitLabel(asmLabel(l))
case FrameEntry(tp, local, stack) => method.visitFrame(tp, local.length, frameTypesToAsm(local, asmLabel).toArray, stack.length, frameTypesToAsm(stack, asmLabel).toArray)
case LineNumber(line, start) => method.visitLineNumber(line, asmLabel(start))
}
}
