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author | Lukas Rytz <lukas.rytz@gmail.com> | 2015-07-03 08:25:30 +0200 |
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committer | Lukas Rytz <lukas.rytz@gmail.com> | 2015-07-03 10:45:02 +0200 |
commit | 0f3505421cd49d20d948808248266998dfc36867 (patch) | |
tree | aabd326d8306e95470217d61a18e75717d329e46 | |
parent | 055a373802a34ee09fc0ed20b2b25c3fa20507d4 (diff) | |
download | scala-0f3505421cd49d20d948808248266998dfc36867.tar.gz scala-0f3505421cd49d20d948808248266998dfc36867.tar.bz2 scala-0f3505421cd49d20d948808248266998dfc36867.zip |
Prevent infinite recursion in ProdConsAnalyzer
When an instruction is its own producer or consumer, the
`initialProducer` / `ultimateConsumer` methods would loop.
While loops or @tailrec annotated methods can generate such bytecode.
3 files changed, 63 insertions, 9 deletions
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/AsmUtils.scala b/src/compiler/scala/tools/nsc/backend/jvm/AsmUtils.scala index 0df1b2029d..cd7e0b83e8 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/AsmUtils.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/AsmUtils.scala @@ -10,6 +10,7 @@ import java.io.{StringWriter, PrintWriter} import scala.tools.asm.util.{CheckClassAdapter, TraceClassVisitor, TraceMethodVisitor, Textifier} import scala.tools.asm.{ClassWriter, Attribute, ClassReader} import scala.collection.convert.decorateAsScala._ +import scala.tools.nsc.backend.jvm.analysis.InitialProducer import scala.tools.nsc.backend.jvm.opt.InlineInfoAttributePrototype object AsmUtils { @@ -81,13 +82,16 @@ object AsmUtils { /** * Returns a human-readable representation of the given instruction. */ - def textify(insn: AbstractInsnNode): String = { - val trace = new TraceMethodVisitor(new Textifier) - insn.accept(trace) - val sw = new StringWriter - val pw = new PrintWriter(sw) - trace.p.print(pw) - sw.toString.trim + def textify(insn: AbstractInsnNode): String = insn match { + case _: InitialProducer => + insn.toString + case _ => + val trace = new TraceMethodVisitor(new Textifier) + insn.accept(trace) + val sw = new StringWriter + val pw = new PrintWriter(sw) + trace.p.print(pw) + sw.toString.trim } /** diff --git a/src/compiler/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzer.scala b/src/compiler/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzer.scala index ad75363102..5d56861ffc 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzer.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzer.scala @@ -103,7 +103,11 @@ class ProdConsAnalyzer(methodNode: MethodNode, classInternalName: InternalName) def initialProducersForValueAt(insn: AbstractInsnNode, slot: Int): Set[AbstractInsnNode] = { def initialProducers(insn: AbstractInsnNode, producedSlot: Int): Set[AbstractInsnNode] = { if (isCopyOperation(insn)) { - _initialProducersCache.getOrElseUpdate((insn, producedSlot), { + val key = (insn, producedSlot) + _initialProducersCache.getOrElseUpdate(key, { + // prevent infinite recursion if an instruction is its own producer or consumer + // see cyclicProdCons in ProdConsAnalyzerTest + _initialProducersCache(key) = Set.empty val (sourceValue, sourceValueSlot) = copyOperationSourceValue(insn, producedSlot) sourceValue.insns.iterator.asScala.flatMap(initialProducers(_, sourceValueSlot)).toSet }) @@ -121,7 +125,11 @@ class ProdConsAnalyzer(methodNode: MethodNode, classInternalName: InternalName) def ultimateConsumersOfValueAt(insn: AbstractInsnNode, slot: Int): Set[AbstractInsnNode] = { def ultimateConsumers(insn: AbstractInsnNode, consumedSlot: Int): Set[AbstractInsnNode] = { if (isCopyOperation(insn)) { - _ultimateConsumersCache.getOrElseUpdate((insn, consumedSlot), { + val key = (insn, consumedSlot) + _ultimateConsumersCache.getOrElseUpdate(key, { + // prevent infinite recursion if an instruction is its own producer or consumer + // see cyclicProdCons in ProdConsAnalyzerTest + _ultimateConsumersCache(key) = Set.empty for { producedSlot <- copyOperationProducedValueSlots(insn, consumedSlot) consumer <- consumersOfValueAt(insn.getNext, producedSlot) diff --git a/test/junit/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzerTest.scala b/test/junit/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzerTest.scala index 9af9ef54fc..a5b3faced8 100644 --- a/test/junit/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzerTest.scala +++ b/test/junit/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzerTest.scala @@ -246,4 +246,46 @@ class ProdConsAnalyzerTest extends ClearAfterClass { testSingleInsn(a.consumersOfOutputsFrom(l2i), "IRETURN") testSingleInsn(a.producersForInputsOf(ret), "L2I") } + + @Test + def cyclicProdCons(): Unit = { + import Opcodes._ + val m = genMethod(descriptor = "(I)I")( + Label(1), + VarOp(ILOAD, 1), + IntOp(BIPUSH, 10), + Op(IADD), // consumer of the above ILOAD + + Op(ICONST_0), + Jump(IF_ICMPNE, Label(2)), + + VarOp(ILOAD, 1), + VarOp(ISTORE, 1), + Jump(GOTO, Label(1)), + + Label(2), + IntOp(BIPUSH, 9), + Op(IRETURN) + ) + m.maxLocals = 2 + m.maxStack = 2 + val a = new ProdConsAnalyzer(m, "C") + + val List(iadd) = findInstr(m, "IADD") + val firstLoad = iadd.getPrevious.getPrevious + assert(firstLoad.getOpcode == ILOAD) + val secondLoad = findInstr(m, "ISTORE").head.getPrevious + assert(secondLoad.getOpcode == ILOAD) + + testSingleInsn(a.producersForValueAt(iadd, 2), "ILOAD") + testSingleInsn(a.initialProducersForValueAt(iadd, 2), "ParameterProducer(1)") + testMultiInsns(a.producersForInputsOf(firstLoad), List("ParameterProducer", "ISTORE")) + testMultiInsns(a.producersForInputsOf(secondLoad), List("ParameterProducer", "ISTORE")) + + testSingleInsn(a.ultimateConsumersOfOutputsFrom(firstLoad), "IADD") + testSingleInsn(a.ultimateConsumersOfOutputsFrom(secondLoad), "IADD") + + testSingleInsn(a.consumersOfOutputsFrom(firstLoad), "IADD") + testSingleInsn(a.consumersOfOutputsFrom(secondLoad), "ISTORE") + } } |