diff options
author | Lukas Rytz <lukas.rytz@gmail.com> | 2015-06-03 22:46:00 +0200 |
---|---|---|
committer | Lukas Rytz <lukas.rytz@gmail.com> | 2015-06-04 20:55:30 +0200 |
commit | b2a78b3ab536658f79e4396201c730a8408d3dd2 (patch) | |
tree | 983d420b6258a1ae9eb7683a27a6c378cc389103 | |
parent | a112422e91018b7f01add6c9d40bec5eb010c321 (diff) | |
download | scala-b2a78b3ab536658f79e4396201c730a8408d3dd2.tar.gz scala-b2a78b3ab536658f79e4396201c730a8408d3dd2.tar.bz2 scala-b2a78b3ab536658f79e4396201c730a8408d3dd2.zip |
Fix aliasing / nullness of CHECKCAST
3 files changed, 30 insertions, 3 deletions
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/analysis/InstructionStackEffect.scala b/src/compiler/scala/tools/nsc/backend/jvm/analysis/InstructionStackEffect.scala index a7d6f74557..98e93c125b 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/analysis/InstructionStackEffect.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/analysis/InstructionStackEffect.scala @@ -249,9 +249,8 @@ object InstructionStackEffect { case ATHROW => t(1, 0) // Frame.execute consumes one stack value - case CHECKCAST => t(0, 0) - - case INSTANCEOF => t(1, 1) + case CHECKCAST | + INSTANCEOF => t(1, 1) // Frame.execute does push(pop()) for both of them case MONITORENTER | MONITOREXIT => t(1, 0) diff --git a/src/compiler/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzer.scala b/src/compiler/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzer.scala index 2cc6d67a3c..31710dcbee 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzer.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzer.scala @@ -179,6 +179,8 @@ final class NullnessInterpreter extends Interpreter[NullnessValue](Opcodes.ASM5) def copyOperation(insn: AbstractInsnNode, value: NullnessValue): NullnessValue = value def unaryOperation(insn: AbstractInsnNode, value: NullnessValue): NullnessValue = (insn.getOpcode: @switch) match { + case Opcodes.CHECKCAST => value + case Opcodes.NEWARRAY | Opcodes.ANEWARRAY => NullnessValue(NotNull, isSize2 = false) diff --git a/test/junit/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzerTest.scala b/test/junit/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzerTest.scala index 3d5343e395..3a85f03da2 100644 --- a/test/junit/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzerTest.scala +++ b/test/junit/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzerTest.scala @@ -202,4 +202,30 @@ class NullnessAnalyzerTest extends ClearAfterClass { (end, 5, Null) // d, no change )) testNullness(a, m, insn, index, nullness) } + + @Test + def testInstanceOf(): Unit = { + val code = + """def f(a: Object) = { + | val x = a + | x.isInstanceOf[Throwable] // x and a remain unknown - INSTANCEOF doesn't throw a NPE on null + | x.toString // x and a are not null + | a.asInstanceOf[String].trim // the stack value (LOAD of local a) is still not-null after the CHECKCAST + |} + """.stripMargin + val List(m) = compileMethods(noOptCompiler)(code) + val a = newNullnessAnalyzer(m) + + val instof = "+INSTANCEOF" + val tost = "+INVOKEVIRTUAL java/lang/Object.toString" + val trim = "INVOKEVIRTUAL java/lang/String.trim" + + for ((insn, index, nullness) <- List( + (instof, 1, Unknown), // a after INSTANCEOF + (instof, 2, Unknown), // x after INSTANCEOF + (tost, 1, NotNull), + (tost, 2, NotNull), + (trim, 3, NotNull) // receiver at `trim` + )) testNullness(a, m, insn, index, nullness) + } } |