diff options
| -rw-r--r-- | src/compiler/scala/tools/nsc/backend/jvm/opt/CallGraph.scala | 26 | ||||
| -rw-r--r-- | src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala | 10 | ||||
| -rw-r--r-- | test/files/neg/inlineMaxSize.check | 4 | ||||
| -rw-r--r-- | test/files/neg/inlineMaxSize.scala | 2 | ||||
| -rw-r--r-- | test/junit/scala/tools/nsc/backend/jvm/opt/InlinerTest.scala | 16 |
5 files changed, 43 insertions, 15 deletions
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/opt/CallGraph.scala b/src/compiler/scala/tools/nsc/backend/jvm/opt/CallGraph.scala index 028f0f8fa6..c6df86b297 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/opt/CallGraph.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/opt/CallGraph.scala @@ -8,12 +8,14 @@ package backend.jvm package opt import scala.reflect.internal.util.{NoPosition, Position} +import scala.tools.asm.{Opcodes, Type} import scala.tools.asm.tree._ import scala.collection.convert.decorateAsScala._ -import scala.tools.nsc.backend.jvm.BTypes.{MethodInlineInfo, InternalName} +import scala.tools.nsc.backend.jvm.BTypes.InternalName import scala.tools.nsc.backend.jvm.BackendReporting._ -import scala.tools.nsc.backend.jvm.opt.BytecodeUtils.AsmAnalyzer +import scala.tools.nsc.backend.jvm.analysis.{NotNull, NullnessAnalyzer} import ByteCodeRepository.{Source, CompilationUnit} +import BytecodeUtils._ class CallGraph[BT <: BTypes](val btypes: BT) { import btypes._ @@ -93,12 +95,13 @@ class CallGraph[BT <: BTypes](val btypes: BT) { // TODO: run dataflow analyses to make the call graph more precise // - producers to get forwarded parameters (ForwardedParam) // - typeAnalysis for more precise argument types, more precise callee - // - nullAnalysis to skip emitting the receiver-null-check when inlining - // TODO: for now we run a basic analyzer to get the stack height at the call site. - // once we run a more elaborate analyzer (types, nullness), we can get the stack height out of there. + // For now we run a NullnessAnalyzer. It is used to determine if the receiver of an instance + // call is known to be not-null, in which case we don't have to emit a null check when inlining. + // It is also used to get the stack height at the call site. localOpt.minimalRemoveUnreachableCode(methodNode, definingClass.internalName) - val analyzer = new AsmAnalyzer(methodNode, definingClass.internalName) + val analyzer = new NullnessAnalyzer + analyzer.analyze(definingClass.internalName, methodNode) methodNode.instructions.iterator.asScala.collect({ case call: MethodInsnNode => @@ -126,13 +129,20 @@ class CallGraph[BT <: BTypes](val btypes: BT) { Nil } + val receiverNotNull = call.getOpcode == Opcodes.INVOKESTATIC || { + val numArgs = Type.getArgumentTypes(call.desc).length + val frame = analyzer.frameAt(call, methodNode) + frame.getStack(frame.getStackSize - 1 - numArgs).nullness == NotNull + } + Callsite( callsiteInstruction = call, callsiteMethod = methodNode, callsiteClass = definingClass, callee = callee, argInfos = argInfos, - callsiteStackHeight = analyzer.frameAt(call).getStackSize, + callsiteStackHeight = analyzer.frameAt(call, methodNode).getStackSize, + receiverKnownNotNull = receiverNotNull, callsitePosition = callsitePositions.getOrElse(call, NoPosition) ) }).toList @@ -154,7 +164,7 @@ class CallGraph[BT <: BTypes](val btypes: BT) { */ final case class Callsite(callsiteInstruction: MethodInsnNode, callsiteMethod: MethodNode, callsiteClass: ClassBType, callee: Either[OptimizerWarning, Callee], argInfos: List[ArgInfo], - callsiteStackHeight: Int, callsitePosition: Position) { + callsiteStackHeight: Int, receiverKnownNotNull: Boolean, callsitePosition: Position) { override def toString = "Invocation of" + s" ${callee.map(_.calleeDeclarationClass.internalName).getOrElse("?")}.${callsiteInstruction.name + callsiteInstruction.desc}" + diff --git a/src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala b/src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala index 3aca15da69..814c78b69c 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala @@ -49,7 +49,7 @@ class Inliner[BT <: BTypes](val btypes: BT) { if (callGraph.callsites contains request.callsiteInstruction) { val r = inline(request.callsiteInstruction, request.callsiteStackHeight, request.callsiteMethod, request.callsiteClass, callee.callee, callee.calleeDeclarationClass, - receiverKnownNotNull = false, keepLineNumbers = false) + request.receiverKnownNotNull, keepLineNumbers = false) for (warning <- r) { if ((callee.annotatedInline && btypes.compilerSettings.YoptWarningEmitAtInlineFailed) || warning.emitWarning(compilerSettings)) { @@ -89,7 +89,7 @@ class Inliner[BT <: BTypes](val btypes: BT) { */ def selectCallsitesForInlining: List[Callsite] = { callsites.valuesIterator.filter({ - case callsite @ Callsite(_, _, _, Right(Callee(callee, calleeDeclClass, safeToInline, _, annotatedInline, _, warning)), _, _, pos) => + case callsite @ Callsite(_, _, _, Right(Callee(callee, calleeDeclClass, safeToInline, _, annotatedInline, _, warning)), _, _, _, pos) => val res = doInlineCallsite(callsite) if (!res) { @@ -112,7 +112,7 @@ class Inliner[BT <: BTypes](val btypes: BT) { res - case Callsite(ins, _, _, Left(warning), _, _, pos) => + case Callsite(ins, _, _, Left(warning), _, _, _, pos) => if (warning.emitWarning(compilerSettings)) backendReporting.inlinerWarning(pos, s"failed to determine if ${ins.name} should be inlined:\n$warning") false @@ -123,7 +123,7 @@ class Inliner[BT <: BTypes](val btypes: BT) { * The current inlining heuristics are simple: inline calls to methods annotated @inline. */ def doInlineCallsite(callsite: Callsite): Boolean = callsite match { - case Callsite(_, _, _, Right(Callee(callee, calleeDeclClass, safeToInline, _, annotatedInline, _, warning)), _, _, pos) => + case Callsite(_, _, _, Right(Callee(callee, calleeDeclClass, safeToInline, _, annotatedInline, _, warning)), _, _, _, pos) => if (compilerSettings.YoptInlineHeuristics.value == "everything") safeToInline else annotatedInline && safeToInline @@ -215,6 +215,7 @@ class Inliner[BT <: BTypes](val btypes: BT) { calleeInfoWarning = infoWarning)), argInfos = Nil, callsiteStackHeight = callsite.callsiteStackHeight, + receiverKnownNotNull = callsite.receiverKnownNotNull, callsitePosition = callsite.callsitePosition ) callGraph.callsites(newCallsiteInstruction) = staticCallsite @@ -444,6 +445,7 @@ class Inliner[BT <: BTypes](val btypes: BT) { callee = originalCallsite.callee, argInfos = Nil, // TODO: re-compute argInfos for new destination (once we actually compute them) callsiteStackHeight = callsiteStackHeight + originalCallsite.callsiteStackHeight, + receiverKnownNotNull = originalCallsite.receiverKnownNotNull, callsitePosition = originalCallsite.callsitePosition ) diff --git a/test/files/neg/inlineMaxSize.check b/test/files/neg/inlineMaxSize.check index d218a8b6e2..9d790e154c 100644 --- a/test/files/neg/inlineMaxSize.check +++ b/test/files/neg/inlineMaxSize.check @@ -2,8 +2,8 @@ inlineMaxSize.scala:7: warning: C::i()I is annotated @inline but could not be in The size of the callsite method C::j()I would exceed the JVM method size limit after inlining C::i()I. - @inline final def j = i + i - ^ + @inline final def j = i + i + i + ^ error: No warnings can be incurred under -Xfatal-warnings. one warning found one error found diff --git a/test/files/neg/inlineMaxSize.scala b/test/files/neg/inlineMaxSize.scala index 16dc0d9538..9d2db1a357 100644 --- a/test/files/neg/inlineMaxSize.scala +++ b/test/files/neg/inlineMaxSize.scala @@ -4,5 +4,5 @@ class C { @inline final def g = f + f + f + f + f + f + f + f + f + f @inline final def h = g + g + g + g + g + g + g + g + g + g @inline final def i = h + h + h + h + h + h + h + h + h + h - @inline final def j = i + i + @inline final def j = i + i + i } diff --git a/test/junit/scala/tools/nsc/backend/jvm/opt/InlinerTest.scala b/test/junit/scala/tools/nsc/backend/jvm/opt/InlinerTest.scala index 0fc3601603..b8c5f85c49 100644 --- a/test/junit/scala/tools/nsc/backend/jvm/opt/InlinerTest.scala +++ b/test/junit/scala/tools/nsc/backend/jvm/opt/InlinerTest.scala @@ -975,4 +975,20 @@ class InlinerTest extends ClearAfterClass { val List(c) = compile(code) assertInvoke(getSingleMethod(c, "t"), "java/lang/Error", "<init>") } + + @Test + def noRedunantNullChecks(): Unit = { + val code = + """class C { + | @inline final def f: String = "hai!" + | def t(c: C) = {c.f; c.f} // null check on the first, but not the second + |} + """.stripMargin + + val List(c) = compile(code) + val t = getSingleMethod(c, "t").instructions + assertNoInvoke(t) + assert(2 == t.collect({case Ldc(_, "hai!") => }).size) // twice the body of f + assert(1 == t.collect({case Jump(IFNONNULL, _) => }).size) // one single null check + } } |