diff options
author | Lukas Rytz <lukas.rytz@typesafe.com> | 2014-11-10 11:01:48 +0100 |
---|---|---|
committer | Lukas Rytz <lukas.rytz@typesafe.com> | 2014-11-10 11:01:48 +0100 |
commit | fad969e211965b10313611436832ca8066d690ef (patch) | |
tree | 44f69582b9c2218ce55c8f41fcbb265cce8a4385 /test | |
parent | b431a4bd83d3bfb2b95d0426d2905b34ce1265ad (diff) | |
parent | 063e7741510bfaf4ccb61f7c0d94cae9353183aa (diff) | |
download | scala-fad969e211965b10313611436832ca8066d690ef.tar.gz scala-fad969e211965b10313611436832ca8066d690ef.tar.bz2 scala-fad969e211965b10313611436832ca8066d690ef.zip |
Merge pull request #4088 from lrytz/opt/cleanupOptimizations
GenBCode: cleanup optimizations
Diffstat (limited to 'test')
8 files changed, 554 insertions, 68 deletions
diff --git a/test/junit/scala/tools/nsc/backend/jvm/CodeGenTools.scala b/test/junit/scala/tools/nsc/backend/jvm/CodeGenTools.scala index b892eb36cf..c1c5a71b83 100644 --- a/test/junit/scala/tools/nsc/backend/jvm/CodeGenTools.scala +++ b/test/junit/scala/tools/nsc/backend/jvm/CodeGenTools.scala @@ -7,6 +7,8 @@ import scala.reflect.io.VirtualDirectory import scala.tools.asm.Opcodes import scala.tools.asm.tree.{AbstractInsnNode, LabelNode, ClassNode, MethodNode} import scala.tools.cmd.CommandLineParser +import scala.tools.nsc.backend.jvm.opt.LocalOpt +import scala.tools.nsc.settings.{MutableSettings, ScalaSettings} import scala.tools.nsc.{Settings, Global} import scala.tools.partest.ASMConverters import scala.collection.JavaConverters._ @@ -79,4 +81,23 @@ object CodeGenTools { def getSingleMethod(classNode: ClassNode, name: String): Method = convertMethod(classNode.methods.asScala.toList.find(_.name == name).get) + + def assertHandlerLabelPostions(h: ExceptionHandler, instructions: List[Instruction], startIndex: Int, endIndex: Int, handlerIndex: Int): Unit = { + val insVec = instructions.toVector + assertTrue(h.start == insVec(startIndex) && h.end == insVec(endIndex) && h.handler == insVec(handlerIndex)) + } + + val localOpt = { + val settings = new MutableSettings(msg => throw new IllegalArgumentException(msg)) + settings.processArguments(List("-Yopt:l:method"), processAll = true) + new LocalOpt(settings) + } + + import scala.language.implicitConversions + + implicit def aliveInstruction(ins: Instruction): (Instruction, Boolean) = (ins, true) + + implicit class MortalInstruction(val ins: Instruction) extends AnyVal { + def dead: (Instruction, Boolean) = (ins, false) + } } diff --git a/test/junit/scala/tools/nsc/backend/jvm/DirectCompileTest.scala b/test/junit/scala/tools/nsc/backend/jvm/DirectCompileTest.scala index 2fb5bb8052..89900291ca 100644 --- a/test/junit/scala/tools/nsc/backend/jvm/DirectCompileTest.scala +++ b/test/junit/scala/tools/nsc/backend/jvm/DirectCompileTest.scala @@ -10,13 +10,12 @@ import scala.tools.partest.ASMConverters._ @RunWith(classOf[JUnit4]) class DirectCompileTest { - val compiler = newCompiler(extraArgs = "-Ybackend:GenBCode") + val compiler = newCompiler(extraArgs = "-Ybackend:GenBCode -Yopt:l:method") @Test def testCompile(): Unit = { val List(("C.class", bytes)) = compile(compiler)( - """ - |class C { + """class C { | def f = 1 |} """.stripMargin) @@ -26,19 +25,12 @@ class DirectCompileTest { @Test def testCompileClasses(): Unit = { - val List(cClass, cModuleClass) = compileClasses(compiler)( - """ - |class C - |object C - """.stripMargin) + val List(cClass, cModuleClass) = compileClasses(compiler)("class C; object C") assertTrue(cClass.name == "C") assertTrue(cModuleClass.name == "C$") - val List(dMirror, dModuleClass) = compileClasses(compiler)( - """ - |object D - """.stripMargin) + val List(dMirror, dModuleClass) = compileClasses(compiler)("object D") assertTrue(dMirror.name == "D") assertTrue(dModuleClass.name == "D$") @@ -47,35 +39,35 @@ class DirectCompileTest { @Test def testCompileMethods(): Unit = { val List(f, g) = compileMethods(compiler)( - """ - |def f = 10 + """def f = 10 |def g = f """.stripMargin) assertTrue(f.name == "f") assertTrue(g.name == "g") - assertTrue(instructionsFromMethod(f).dropNonOp === + assertSameCode(instructionsFromMethod(f).dropNonOp, List(IntOp(BIPUSH, 10), Op(IRETURN))) - assertTrue(instructionsFromMethod(g).dropNonOp === - List(VarOp(ALOAD, 0), Invoke(INVOKEVIRTUAL, "C", "f", "()I", false), Op(IRETURN))) + assertSameCode(instructionsFromMethod(g).dropNonOp, + List(VarOp(ALOAD, 0), Invoke(INVOKEVIRTUAL, "C", "f", "()I", itf = false), Op(IRETURN))) } @Test def testDropNonOpAliveLabels(): Unit = { + // makes sure that dropNoOp doesn't drop labels that are being used val List(f) = compileMethods(compiler)("""def f(x: Int) = if (x == 0) "a" else "b"""") - assertTrue(instructionsFromMethod(f).dropNonOp === List( - VarOp(ILOAD, 1), - Op(ICONST_0), - Jump(IF_ICMPEQ, Label(6)), - Jump(GOTO, Label(10)), - Label(6), - Ldc(LDC, "a"), - Jump(GOTO, Label(13)), - Label(10), - Ldc(LDC, "b"), - Label(13), - Op(ARETURN) + assertSameCode(instructionsFromMethod(f).dropLinesFrames, List( + Label(0), + VarOp(ILOAD, 1), + Op(ICONST_0), + Jump(IF_ICMPNE, + Label(7)), + Ldc(LDC, "a"), + Op(ARETURN), + Label(7), + Ldc(LDC, "b"), + Op(ARETURN), + Label(11) )) } } diff --git a/test/junit/scala/tools/nsc/backend/jvm/opt/CompactLocalVariablesTest.scala b/test/junit/scala/tools/nsc/backend/jvm/opt/CompactLocalVariablesTest.scala new file mode 100644 index 0000000000..fc748196d0 --- /dev/null +++ b/test/junit/scala/tools/nsc/backend/jvm/opt/CompactLocalVariablesTest.scala @@ -0,0 +1,80 @@ +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,recurse-unreachable-jumps,compact-locals") + val noCompactVarsCompiler = newCompiler(extraArgs = "-target:jvm-1.6 -Ybackend:GenBCode -Yopt:unreachable-code,recurse-unreachable-jumps") + + @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) + } +} diff --git a/test/junit/scala/tools/nsc/backend/jvm/opt/EmptyExceptionHandlersTest.scala b/test/junit/scala/tools/nsc/backend/jvm/opt/EmptyExceptionHandlersTest.scala index 57fa1a7b66..7d83c54b5b 100644 --- a/test/junit/scala/tools/nsc/backend/jvm/opt/EmptyExceptionHandlersTest.scala +++ b/test/junit/scala/tools/nsc/backend/jvm/opt/EmptyExceptionHandlersTest.scala @@ -26,7 +26,7 @@ class EmptyExceptionHandlersTest { Op(RETURN) ) assertTrue(convertMethod(asmMethod).handlers.length == 1) - LocalOpt.removeEmptyExceptionHandlers(asmMethod) + localOpt.removeEmptyExceptionHandlers(asmMethod) assertTrue(convertMethod(asmMethod).handlers.isEmpty) } @@ -35,12 +35,8 @@ class EmptyExceptionHandlersTest { val handlers = List(ExceptionHandler(Label(1), Label(2), Label(2), Some(exceptionDescriptor))) val asmMethod = genMethod(handlers = handlers)( Label(1), // nops only - Op(NOP), - Op(NOP), Jump(GOTO, Label(3)), - Op(NOP), Label(3), - Op(NOP), Jump(GOTO, Label(4)), Label(2), // handler @@ -51,7 +47,7 @@ class EmptyExceptionHandlersTest { Op(RETURN) ) assertTrue(convertMethod(asmMethod).handlers.length == 1) - LocalOpt.removeEmptyExceptionHandlers(asmMethod) + localOpt.removeEmptyExceptionHandlers(asmMethod) assertTrue(convertMethod(asmMethod).handlers.isEmpty) } diff --git a/test/junit/scala/tools/nsc/backend/jvm/opt/EmptyLabelsAndLineNumbersTest.scala b/test/junit/scala/tools/nsc/backend/jvm/opt/EmptyLabelsAndLineNumbersTest.scala new file mode 100644 index 0000000000..8c0168826e --- /dev/null +++ b/test/junit/scala/tools/nsc/backend/jvm/opt/EmptyLabelsAndLineNumbersTest.scala @@ -0,0 +1,99 @@ +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 scala.tools.testing.AssertUtil._ + +import CodeGenTools._ +import scala.tools.partest.ASMConverters +import ASMConverters._ + +@RunWith(classOf[JUnit4]) +class EmptyLabelsAndLineNumbersTest { + @Test + def removeEmptyLineNumbers(): Unit = { + val ops = List[(Instruction, Boolean)]( + Label(1), + LineNumber(1, Label(1)), + Label(2), + Label(3), + Op(RETURN), + + Label(4), + LineNumber(4, Label(4)).dead, + LineNumber(5, Label(4)), + Op(RETURN), + + Label(5), + LineNumber(6, Label(5)).dead, + Label(6), + Label(7), + LineNumber(7, Label(7)), + Op(RETURN), + + Label(9), + LineNumber(8, Label(9)).dead, + Label(10) + ) + + val method = genMethod()(ops.map(_._1): _*) + assertTrue(localOpt.removeEmptyLineNumbers(method)) + assertSameCode(instructionsFromMethod(method), ops.filter(_._2).map(_._1)) + } + + @Test + def badlyLocatedLineNumbers(): Unit = { + def t(ops: Instruction*) = + assertThrows[AssertionError](localOpt.removeEmptyLineNumbers(genMethod()(ops: _*))) + + // line numbers have to be right after their referenced label node + t(LineNumber(0, Label(1)), Label(1)) + t(Label(0), Label(1), LineNumber(0, Label(0))) + } + + @Test + def removeEmptyLabels(): Unit = { + val handler = List(ExceptionHandler(Label(4), Label(5), Label(6), Some("java/lang/Throwable"))) + def ops(target1: Int, target2: Int, target3: Int, target4: Int, target5: Int, target6: Int) = List[(Instruction, Boolean)]( + Label(1), + Label(2).dead, + Label(3).dead, + LineNumber(3, Label(target1)), + VarOp(ILOAD, 1), + Jump(IFGE, Label(target2)), + + Label(4), + Label(5).dead, + Label(6).dead, + VarOp(ILOAD, 2), + Jump(IFGE, Label(target3)), + + Label(7), + Label(8).dead, + Label(9).dead, + Op(RETURN), + + LookupSwitch(LOOKUPSWITCH, Label(target4), List(1,2), List(Label(target4), Label(target5))), + TableSwitch(TABLESWITCH, 1, 2, Label(target4), List(Label(target4), Label(target5))), + + Label(10), + LineNumber(10, Label(10)), + Label(11).dead, + LineNumber(12, Label(target6)) + ) + + val method = genMethod(handlers = handler)(ops(2, 3, 8, 8, 9, 11).map(_._1): _*) + assertTrue(localOpt.removeEmptyLabelNodes(method)) + val m = convertMethod(method) + assertSameCode(m.instructions, ops(1, 1, 7, 7, 7, 10).filter(_._2).map(_._1)) + assertTrue(m.handlers match { + case List(ExceptionHandler(Label(4), Label(4), Label(4), _)) => true + case _ => false + }) + } +} diff --git a/test/junit/scala/tools/nsc/backend/jvm/opt/MethodLevelOpts.scala b/test/junit/scala/tools/nsc/backend/jvm/opt/MethodLevelOpts.scala new file mode 100644 index 0000000000..5b0f0f238a --- /dev/null +++ b/test/junit/scala/tools/nsc/backend/jvm/opt/MethodLevelOpts.scala @@ -0,0 +1,83 @@ +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 scala.tools.testing.AssertUtil._ + +import CodeGenTools._ +import scala.tools.partest.ASMConverters +import ASMConverters._ + +@RunWith(classOf[JUnit4]) +class MethodLevelOpts { + val methodOptCompiler = newCompiler(extraArgs = "-target:jvm-1.6 -Ybackend:GenBCode -Yopt:l:method") + + def wrapInDefault(code: Instruction*) = List(Label(0), LineNumber(1, Label(0))) ::: code.toList ::: List(Label(1)) + + @Test + def eliminateEmptyTry(): Unit = { + val code = "def f = { try {} catch { case _: Throwable => 0; () }; 1 }" + assertSameCode(singleMethodInstructions(methodOptCompiler)(code), wrapInDefault(Op(ICONST_1), Op(IRETURN))) + } + + @Test + def cannotEliminateLoadBoxedUnit(): Unit = { + // the compiler inserts a boxed into the try block. it's therefore non-empty (and live) and not eliminated. + val code = "def f = { try {} catch { case _: Throwable => 0 }; 1 }" + val m = singleMethod(methodOptCompiler)(code) + assertTrue(m.handlers.length == 1) + assertSameCode(m.instructions.take(3), List(Label(0), LineNumber(1, Label(0)), Field(GETSTATIC, "scala/runtime/BoxedUnit", "UNIT", "Lscala/runtime/BoxedUnit;"))) + } + + @Test + def inlineThrowInCatchNotTry(): Unit = { + // the try block does not contain the `ATHROW` instruction, but in the catch block, `ATHROW` is inlined + val code = "def f(e: Exception) = throw { try e catch { case _: Throwable => e } }" + val m = singleMethod(methodOptCompiler)(code) + assertHandlerLabelPostions(m.handlers.head, m.instructions, 0, 3, 5) + assertSameCode(m.instructions, + wrapInDefault(VarOp(ALOAD, 1), Label(3), Op(ATHROW), Label(5), FrameEntry(4, List(), List("java/lang/Throwable")), Op(POP), VarOp(ALOAD, 1), Op(ATHROW)) + ) + } + + @Test + def inlineReturnInCachtNotTry(): Unit = { + val code = "def f: Int = return { try 1 catch { case _: Throwable => 2 } }" + // cannot inline the IRETURN into the try block (because RETURN may throw IllegalMonitorState) + val m = singleMethod(methodOptCompiler)(code) + assertHandlerLabelPostions(m.handlers.head, m.instructions, 0, 3, 5) + assertSameCode(m.instructions, + wrapInDefault(Op(ICONST_1), Label(3), Op(IRETURN), Label(5), FrameEntry(4, List(), List("java/lang/Throwable")), Op(POP), Op(ICONST_2), Op(IRETURN))) + } + + @Test + def simplifyJumpsInTryCatchFinally(): Unit = { + val code = + """def f: Int = + | try { + | return 1 + | } catch { + | case _: Throwable => + | return 2 + | } finally { + | return 2 + | // dead + | val x = try 10 catch { case _: Throwable => 11 } + | println(x) + | } + """.stripMargin + val m = singleMethod(methodOptCompiler)(code) + assertTrue(m.handlers.length == 2) + assertSameCode(m.instructions.dropNonOp, // drop line numbers and lables that are only used by line numbers + + // one single label left :-) + List(Op(ICONST_1), VarOp(ISTORE, 2), Jump(GOTO, Label(20)), Op(POP), Op(ICONST_2), VarOp(ISTORE, 2), Jump(GOTO, Label(20)), VarOp(ASTORE, 3), Op(ICONST_2), Op(IRETURN), Label(20), Op(ICONST_2), Op(IRETURN)) + ) + } +} diff --git a/test/junit/scala/tools/nsc/backend/jvm/opt/SimplifyJumpsTest.scala b/test/junit/scala/tools/nsc/backend/jvm/opt/SimplifyJumpsTest.scala new file mode 100644 index 0000000000..360fa1d23d --- /dev/null +++ b/test/junit/scala/tools/nsc/backend/jvm/opt/SimplifyJumpsTest.scala @@ -0,0 +1,221 @@ +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 SimplifyJumpsTest { + @Test + def simpleGotoReturn(): Unit = { + val ops = List( + Jump(GOTO, Label(2)), // replaced by RETURN + Op(ICONST_1), // need some code, otherwise removeJumpToSuccessor kicks in + Op(POP), + Label(1), // multiple labels OK + Label(2), + Label(3), + Op(RETURN) + ) + val method = genMethod()(ops: _*) + assertTrue(localOpt.simplifyJumps(method)) + assertSameCode(instructionsFromMethod(method), Op(RETURN) :: ops.tail) + } + + @Test + def simpleGotoThrow(): Unit = { + val rest = List( + Op(ICONST_1), // need some code, otherwise removeJumpToSuccessor kicks in + Op(POP), + Label(1), + Label(2), + Label(3), + Op(ATHROW) + ) + val method = genMethod()( + Op(ACONST_NULL) :: + Jump(GOTO, Label(2)) :: // replaced by ATHROW + rest: _* + ) + assertTrue(localOpt.simplifyJumps(method)) + assertSameCode(instructionsFromMethod(method), Op(ACONST_NULL) :: Op(ATHROW) :: rest) + } + + @Test + def gotoThrowInTry(): Unit = { + val handler = List(ExceptionHandler(Label(1), Label(2), Label(4), Some("java/lang/Throwable"))) + val initialInstrs = List( + Label(1), + Op(ACONST_NULL), + Jump(GOTO, Label(3)), // not by ATHROW (would move the ATHROW into a try block) + Label(2), + Op(ICONST_1), // need some code, otherwise removeJumpToSuccessor kicks in + Op(POP), + Label(3), + Op(ATHROW), + Label(4), + Op(POP), + Op(RETURN) + ) + val method = genMethod(handlers = handler)(initialInstrs: _*) + assertFalse(localOpt.simplifyJumps(method)) + assertSameCode(instructionsFromMethod(method), initialInstrs) + + val optMethod = genMethod()(initialInstrs: _*) // no handler + assertTrue(localOpt.simplifyJumps(optMethod)) + assertSameCode(instructionsFromMethod(optMethod).take(3), List(Label(1), Op(ACONST_NULL), Op(ATHROW))) + } + + @Test + def simplifyBranchOverGoto(): Unit = { + val begin = List( + VarOp(ILOAD, 1), + Jump(IFGE, Label(2)) + ) + val rest = List( + Jump(GOTO, Label(3)), + Label(11), // other labels here are allowed + Label(2), + VarOp(ILOAD, 1), + Op(RETURN), + Label(3), + VarOp(ILOAD, 1), + Op(IRETURN) + ) + val method = genMethod()(begin ::: rest: _*) + assertTrue(localOpt.simplifyJumps(method)) + assertSameCode( + instructionsFromMethod(method), + List(VarOp(ILOAD, 1), Jump(IFLT, Label(3))) ::: rest.tail ) + + // no label allowed between begin and rest. if there's another label, then there could be a + // branch that label. eliminating the GOTO would change the behavior. + val nonOptMethod = genMethod()(begin ::: Label(22) :: rest: _*) + assertFalse(localOpt.simplifyJumps(nonOptMethod)) + } + + @Test + def ensureGotoRemoved(): Unit = { + def code(jumps: Instruction*) = List( + VarOp(ILOAD, 1)) ::: jumps.toList ::: List( + Label(2), + + Op(RETURN), + Label(3), + Op(RETURN) + ) + + // ensures that the goto is safely removed. ASM supports removing while iterating, but not the + // next element of the current. Here, the current is the IFGE, the next is the GOTO. + val method = genMethod()(code(Jump(IFGE, Label(2)), Jump(GOTO, Label(3))): _*) + assertTrue(localOpt.simplifyJumps(method)) + assertSameCode(instructionsFromMethod(method), code(Jump(IFLT, Label(3)))) + } + + @Test + def removeJumpToSuccessor(): Unit = { + val ops = List( + Jump(GOTO, Label(1)), + Label(11), + Label(1), + Label(2), + VarOp(ILOAD, 1), + Op(IRETURN) + ) + val method = genMethod()(ops: _*) + assertTrue(localOpt.simplifyJumps(method)) + assertSameCode(instructionsFromMethod(method), ops.tail) + } + + @Test + def collapseJumpChains(): Unit = { + def ops(target1: Int, target2: Int, target3: Int) = List( + VarOp(ILOAD, 1), + Jump(IFGE, Label(target1)), // initially 1, then 3 + VarOp(ILOAD, 1), + Op(IRETURN), + + Label(2), + Jump(GOTO, Label(target3)), + + Label(1), + Jump(GOTO, Label(target2)), // initially 2, then 3 + + VarOp(ILOAD, 1), // some code to prevent jumpToSuccessor optimization (once target2 is replaced by 3) + Op(RETURN), + + Label(3), + VarOp(ILOAD, 1), + Op(IRETURN) + ) + val method = genMethod()(ops(1, 2, 3): _*) + assertTrue(localOpt.simplifyJumps(method)) + assertSameCode(instructionsFromMethod(method), ops(3, 3, 3)) + } + + @Test + def collapseJumpChainLoop(): Unit = { + def ops(target: Int) = List( + VarOp(ILOAD, 1), + Jump(IFGE, Label(target)), + + Label(4), + Jump(GOTO, Label(3)), + + VarOp(ILOAD, 1), // some code to prevent jumpToSuccessor (label 3) + Op(IRETURN), + + Label(3), + Jump(GOTO, Label(4)), + + Label(2), + Jump(GOTO, Label(3)) + ) + + val method = genMethod()(ops(2): _*) + assertTrue(localOpt.simplifyJumps(method)) + assertSameCode(instructionsFromMethod(method), ops(3)) + } + + @Test + def simplifyThenElseSameTarget(): Unit = { + def ops(jumpOp: Instruction) = List( + VarOp(ILOAD, 1), + jumpOp, + Label(2), + Jump(GOTO, Label(1)), + + VarOp(ILOAD, 1), // some code to prevent jumpToSuccessor (label 1) + Op(IRETURN), + + Label(1), + VarOp(ILOAD, 1), + Op(IRETURN) + ) + + val method = genMethod()(ops(Jump(IFGE, Label(1))): _*) + assertTrue(localOpt.simplifyJumps(method)) + assertSameCode(instructionsFromMethod(method), ops(Op(POP))) + } + + @Test + def thenElseSameTargetLoop(): Unit = { + def ops(br: List[Instruction]) = List( + VarOp(ILOAD, 1), + VarOp(ILOAD, 2)) ::: br ::: List( + Label(1), + Jump(GOTO, Label(1)) + ) + val method = genMethod()(ops(List(Jump(IF_ICMPGE, Label(1)))): _*) + assertTrue(localOpt.simplifyJumps(method)) + assertSameCode(instructionsFromMethod(method), ops(List(Op(POP), Op(POP)))) + } +} diff --git a/test/junit/scala/tools/nsc/backend/jvm/opt/UnreachableCodeTest.scala b/test/junit/scala/tools/nsc/backend/jvm/opt/UnreachableCodeTest.scala index a3bd7ae6fe..4a45dd9138 100644 --- a/test/junit/scala/tools/nsc/backend/jvm/opt/UnreachableCodeTest.scala +++ b/test/junit/scala/tools/nsc/backend/jvm/opt/UnreachableCodeTest.scala @@ -16,12 +16,20 @@ import ASMConverters._ @RunWith(classOf[JUnit4]) class UnreachableCodeTest { - import UnreachableCodeTest._ + + def assertEliminateDead(code: (Instruction, Boolean)*): Unit = { + val method = genMethod()(code.map(_._1): _*) + localOpt.removeUnreachableCodeImpl(method, "C") + val nonEliminated = instructionsFromMethod(method) + val expectedLive = code.filter(_._2).map(_._1).toList + assertSameCode(nonEliminated, expectedLive) + } // jvm-1.6 enables emitting stack map frames, which impacts the code generation wrt dead basic blocks, // see comment in BCodeBodyBuilder - val dceCompiler = newCompiler(extraArgs = "-target:jvm-1.6 -Ybackend:GenBCode -Yopt:unreachable-code") - val noOptCompiler = newCompiler(extraArgs = "-target:jvm-1.6 -Ybackend:GenBCode -Yopt:l:none") + val methodOptCompiler = newCompiler(extraArgs = "-target:jvm-1.6 -Ybackend:GenBCode -Yopt:l:method") + val dceCompiler = newCompiler(extraArgs = "-target:jvm-1.6 -Ybackend:GenBCode -Yopt:unreachable-code") + val noOptCompiler = newCompiler(extraArgs = "-target:jvm-1.6 -Ybackend:GenBCode -Yopt:l:none") // jvm-1.5 disables computing stack map frames, and it emits dead code as-is. val noOptNoFramesCompiler = newCompiler(extraArgs = "-target:jvm-1.5 -Ybackend:GenBCode -Yopt:l:none") @@ -48,8 +56,8 @@ class UnreachableCodeTest { @Test def eliminateNop(): Unit = { assertEliminateDead( - // not dead, since visited by data flow analysis. need a different opt to eliminate it. - Op(NOP), + // reachable, but removed anyway. + Op(NOP).dead, Op(RETURN), Op(NOP).dead ) @@ -136,28 +144,31 @@ class UnreachableCodeTest { @Test def eliminateDeadCatchBlocks(): Unit = { + // the Label(1) is live: it's used in the local variable descriptor table (local variable "this" has a range from 0 to 1). + def wrapInDefault(code: Instruction*) = List(Label(0), LineNumber(1, Label(0))) ::: code.toList ::: List(Label(1)) + val code = "def f: Int = { return 0; try { 1 } catch { case _: Exception => 2 } }" - assertSameCode(singleMethodInstructions(dceCompiler)(code).dropNonOp, - List(Op(ICONST_0), Op(IRETURN))) + val m = singleMethod(dceCompiler)(code) + assertTrue(m.handlers.isEmpty) // redundant (if code is gone, handler is gone), but done once here for extra safety + assertSameCode(m.instructions, + wrapInDefault(Op(ICONST_0), Op(IRETURN))) val code2 = "def f: Unit = { try { } catch { case _: Exception => () }; () }" - // DCE only removes dead basic blocks, but not NOPs, and also not useless jumps - assertSameCode(singleMethodInstructions(dceCompiler)(code2).dropNonOp, - List(Op(NOP), Jump(GOTO, Label(33)), Label(33), Op(RETURN))) + // requires fixpoint optimization of methodOptCompiler (dce alone is not enough): first the handler is eliminated, then it's dead catch block. + assertSameCode(singleMethodInstructions(methodOptCompiler)(code2), wrapInDefault(Op(RETURN))) val code3 = "def f: Unit = { try { } catch { case _: Exception => try { } catch { case _: Exception => () } }; () }" - assertSameCode(singleMethodInstructions(dceCompiler)(code3).dropNonOp, - List(Op(NOP), Jump(GOTO, Label(33)), Label(33), Op(RETURN))) + assertSameCode(singleMethodInstructions(methodOptCompiler)(code3), wrapInDefault(Op(RETURN))) + // this example requires two iterations to get rid of the outer handler. + // the first iteration of DCE cannot remove the inner handler. then the inner (empty) handler is removed. + // then the second iteration of DCE removes the inner catch block, and then the outer handler is removed. val code4 = "def f: Unit = { try { try { } catch { case _: Exception => () } } catch { case _: Exception => () }; () }" - assertSameCode(singleMethodInstructions(dceCompiler)(code4).dropNonOp, - List(Op(NOP), Jump(GOTO, Label(4)), Label(4), Jump(GOTO, Label(7)), Label(7), Op(RETURN))) + assertSameCode(singleMethodInstructions(methodOptCompiler)(code4), wrapInDefault(Op(RETURN))) } @Test // test the dce-testing tools def metaTest(): Unit = { - assertEliminateDead() // no instructions - assertThrows[AssertionError]( assertEliminateDead(Op(RETURN).dead), _.contains("Expected: List()\nActual : List(Op(RETURN))") @@ -198,20 +209,3 @@ class UnreachableCodeTest { List(FrameEntry(F_FULL, List(INTEGER, DOUBLE, Label(1)), List("java/lang/Object", Label(3))), Label(1), Label(3))) } } - -object UnreachableCodeTest { - import scala.language.implicitConversions - implicit def aliveInstruction(ins: Instruction): (Instruction, Boolean) = (ins, true) - - implicit class MortalInstruction(val ins: Instruction) extends AnyVal { - def dead: (Instruction, Boolean) = (ins, false) - } - - def assertEliminateDead(code: (Instruction, Boolean)*): Unit = { - val cls = wrapInClass(genMethod()(code.map(_._1): _*)) - LocalOpt.removeUnreachableCode(cls) - val nonEliminated = instructionsFromMethod(cls.methods.get(0)) - val expectedLive = code.filter(_._2).map(_._1).toList - assertSameCode(nonEliminated, expectedLive) - } -} |