From b3db5c34c72dfa80a3a049a896a65b7c7da56e89 Mon Sep 17 00:00:00 2001 From: Lukas Rytz Date: Tue, 7 Oct 2014 21:19:58 +0200 Subject: GenBCode: Command-line flags for enabling cleanup optimizations Add command-line flags `Yopt:...` for simplifying jumps, eliminating stale line number and label nodes. `LocalOpt.methodOptimizations` applies all enabled intra-method optimizations in the right order. Some cleanups for unreachable code elimination and its tests. --- .../scala/tools/nsc/backend/jvm/CodeGenTools.scala | 16 ++++++ .../tools/nsc/backend/jvm/DirectCompileTest.scala | 50 ++++++++---------- .../jvm/opt/EmptyExceptionHandlersTest.scala | 8 +-- .../jvm/opt/EmptyLabelsAndLineNumbersTest.scala | 8 ++- .../nsc/backend/jvm/opt/SimplifyJumpsTest.scala | 24 ++++----- .../nsc/backend/jvm/opt/UnreachableCodeTest.scala | 60 ++++++++++------------ 6 files changed, 81 insertions(+), 85 deletions(-) (limited to 'test/junit') diff --git a/test/junit/scala/tools/nsc/backend/jvm/CodeGenTools.scala b/test/junit/scala/tools/nsc/backend/jvm/CodeGenTools.scala index b892eb36cf..857263d65f 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 +81,18 @@ object CodeGenTools { def getSingleMethod(classNode: ClassNode, name: String): Method = convertMethod(classNode.methods.asScala.toList.find(_.name == name).get) + + 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/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 index 213af4bcc1..8c0168826e 100644 --- a/test/junit/scala/tools/nsc/backend/jvm/opt/EmptyLabelsAndLineNumbersTest.scala +++ b/test/junit/scala/tools/nsc/backend/jvm/opt/EmptyLabelsAndLineNumbersTest.scala @@ -15,8 +15,6 @@ import ASMConverters._ @RunWith(classOf[JUnit4]) class EmptyLabelsAndLineNumbersTest { - import UnreachableCodeTest._ // ".dead" extension method on instructions - @Test def removeEmptyLineNumbers(): Unit = { val ops = List[(Instruction, Boolean)]( @@ -44,14 +42,14 @@ class EmptyLabelsAndLineNumbersTest { ) val method = genMethod()(ops.map(_._1): _*) - assertTrue(LocalOpt.removeEmptyLineNumbers(method)) + 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: _*))) + assertThrows[AssertionError](localOpt.removeEmptyLineNumbers(genMethod()(ops: _*))) // line numbers have to be right after their referenced label node t(LineNumber(0, Label(1)), Label(1)) @@ -90,7 +88,7 @@ class EmptyLabelsAndLineNumbersTest { ) val method = genMethod(handlers = handler)(ops(2, 3, 8, 8, 9, 11).map(_._1): _*) - assertTrue(LocalOpt.removeEmptyLabelNodes(method)) + 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 { diff --git a/test/junit/scala/tools/nsc/backend/jvm/opt/SimplifyJumpsTest.scala b/test/junit/scala/tools/nsc/backend/jvm/opt/SimplifyJumpsTest.scala index a51bce7939..360fa1d23d 100644 --- a/test/junit/scala/tools/nsc/backend/jvm/opt/SimplifyJumpsTest.scala +++ b/test/junit/scala/tools/nsc/backend/jvm/opt/SimplifyJumpsTest.scala @@ -26,7 +26,7 @@ class SimplifyJumpsTest { Op(RETURN) ) val method = genMethod()(ops: _*) - assertTrue(LocalOpt.simplifyJumps(method)) + assertTrue(localOpt.simplifyJumps(method)) assertSameCode(instructionsFromMethod(method), Op(RETURN) :: ops.tail) } @@ -45,7 +45,7 @@ class SimplifyJumpsTest { Jump(GOTO, Label(2)) :: // replaced by ATHROW rest: _* ) - assertTrue(LocalOpt.simplifyJumps(method)) + assertTrue(localOpt.simplifyJumps(method)) assertSameCode(instructionsFromMethod(method), Op(ACONST_NULL) :: Op(ATHROW) :: rest) } @@ -66,11 +66,11 @@ class SimplifyJumpsTest { Op(RETURN) ) val method = genMethod(handlers = handler)(initialInstrs: _*) - assertFalse(LocalOpt.simplifyJumps(method)) + assertFalse(localOpt.simplifyJumps(method)) assertSameCode(instructionsFromMethod(method), initialInstrs) val optMethod = genMethod()(initialInstrs: _*) // no handler - assertTrue(LocalOpt.simplifyJumps(optMethod)) + assertTrue(localOpt.simplifyJumps(optMethod)) assertSameCode(instructionsFromMethod(optMethod).take(3), List(Label(1), Op(ACONST_NULL), Op(ATHROW))) } @@ -91,7 +91,7 @@ class SimplifyJumpsTest { Op(IRETURN) ) val method = genMethod()(begin ::: rest: _*) - assertTrue(LocalOpt.simplifyJumps(method)) + assertTrue(localOpt.simplifyJumps(method)) assertSameCode( instructionsFromMethod(method), List(VarOp(ILOAD, 1), Jump(IFLT, Label(3))) ::: rest.tail ) @@ -99,7 +99,7 @@ class SimplifyJumpsTest { // 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)) + assertFalse(localOpt.simplifyJumps(nonOptMethod)) } @Test @@ -116,7 +116,7 @@ class SimplifyJumpsTest { // 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)) + assertTrue(localOpt.simplifyJumps(method)) assertSameCode(instructionsFromMethod(method), code(Jump(IFLT, Label(3)))) } @@ -131,7 +131,7 @@ class SimplifyJumpsTest { Op(IRETURN) ) val method = genMethod()(ops: _*) - assertTrue(LocalOpt.simplifyJumps(method)) + assertTrue(localOpt.simplifyJumps(method)) assertSameCode(instructionsFromMethod(method), ops.tail) } @@ -157,7 +157,7 @@ class SimplifyJumpsTest { Op(IRETURN) ) val method = genMethod()(ops(1, 2, 3): _*) - assertTrue(LocalOpt.simplifyJumps(method)) + assertTrue(localOpt.simplifyJumps(method)) assertSameCode(instructionsFromMethod(method), ops(3, 3, 3)) } @@ -181,7 +181,7 @@ class SimplifyJumpsTest { ) val method = genMethod()(ops(2): _*) - assertTrue(LocalOpt.simplifyJumps(method)) + assertTrue(localOpt.simplifyJumps(method)) assertSameCode(instructionsFromMethod(method), ops(3)) } @@ -202,7 +202,7 @@ class SimplifyJumpsTest { ) val method = genMethod()(ops(Jump(IFGE, Label(1))): _*) - assertTrue(LocalOpt.simplifyJumps(method)) + assertTrue(localOpt.simplifyJumps(method)) assertSameCode(instructionsFromMethod(method), ops(Op(POP))) } @@ -215,7 +215,7 @@ class SimplifyJumpsTest { Jump(GOTO, Label(1)) ) val method = genMethod()(ops(List(Jump(IF_ICMPGE, Label(1)))): _*) - assertTrue(LocalOpt.simplifyJumps(method)) + 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) - } -} -- cgit v1.2.3