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package scala.tools.nsc
package backend.jvm
package opt
import org.junit.runner.RunWith
import org.junit.runners.JUnit4
import org.junit.Test
import scala.tools.asm.Opcodes._
import org.junit.Assert._
import CodeGenTools._
import scala.tools.partest.ASMConverters
import ASMConverters._
@RunWith(classOf[JUnit4])
class CompactLocalVariablesTest {
// recurse-unreachable-jumps is required for eliminating catch blocks, in the first dce round they
// are still live.only after eliminating the empty handler the catch blocks become unreachable.
val methodOptCompiler = newCompiler(extraArgs = "-target:jvm-1.6 -Ybackend:GenBCode -Yopt:unreachable-code,compact-locals")
val noCompactVarsCompiler = newCompiler(extraArgs = "-target:jvm-1.6 -Ybackend:GenBCode -Yopt:unreachable-code")
@Test
def compactUnused(): Unit = {
val code =
"""def f: Double = {
| try { }
| catch {
| case _: Throwable =>
| // eliminated by dce
| val i = 1
| val d = 1d
| val f = 1f
| val l = 1l
| }
|
| val i = 1 // variable index 1 (it's an instance method, so at index 0 we have `this`)
| val d = 1d // 2,3
| val f = 1f // 4
| val l = 1l // 5,6
|
| try { }
| catch {
| case _: Throwable =>
| // eliminated by dce
| val i = 1
| val d = 1d
| val f = 1f
| val l = 1l
| }
|
| val ii = 1 // 7
| val dd = 1d // 8,9
| val ff = 1f // 10
| val ll = 1l // 11,12
|
| i + ii + d + dd + f + ff + l + ll
|}
|""".stripMargin
val List(noCompact) = compileMethods(noCompactVarsCompiler)(code)
val List(withCompact) = compileMethods(methodOptCompiler)(code)
// code is the same, except for local var indices
assertTrue(noCompact.instructions.size == withCompact.instructions.size)
val varOpSlots = convertMethod(withCompact).instructions collect {
case VarOp(_, v) => v
}
assertTrue(varOpSlots.toString, varOpSlots == List(1, 2, 4, 5, 7, 8, 10, 11, // stores
1, 7, 2, 8, 4, 10, 5, 11)) // loads
// the local variables descriptor table is cleaned up to remove stale entries after dce,
// also when the slots are not compacted
assertTrue(noCompact.localVariables.size == withCompact.localVariables.size)
assertTrue(noCompact.maxLocals == 25)
assertTrue(withCompact.maxLocals == 13)
}
}
|
