diff options
Diffstat (limited to 'test/junit')
| -rw-r--r-- | test/junit/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzerTest.scala | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/test/junit/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzerTest.scala b/test/junit/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzerTest.scala new file mode 100644 index 0000000000..92574329db --- /dev/null +++ b/test/junit/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzerTest.scala @@ -0,0 +1,205 @@ +package scala.tools.nsc +package backend.jvm +package analysis + +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.asm.tree.{AbstractInsnNode, MethodNode} +import scala.tools.nsc.backend.jvm.BTypes._ +import scala.tools.partest.ASMConverters +import ASMConverters._ +import scala.tools.testing.ClearAfterClass +import scala.tools.nsc.backend.jvm.opt.BytecodeUtils._ +import AsmUtils._ + +import scala.collection.convert.decorateAsScala._ + +object NullnessAnalyzerTest extends ClearAfterClass.Clearable { + var noOptCompiler = newCompiler(extraArgs = "-Ybackend:GenBCode -Yopt:l:none") + + def clear(): Unit = { + noOptCompiler = null + } +} + +@RunWith(classOf[JUnit4]) +class NullnessAnalyzerTest extends ClearAfterClass { + ClearAfterClass.stateToClear = NullnessAnalyzerTest + val noOptCompiler = NullnessAnalyzerTest.noOptCompiler + + def newNullnessAnalyzer(methodNode: MethodNode, classInternalName: InternalName = "C"): NullnessAnalyzer = { + val nullnessAnalyzer = new NullnessAnalyzer + nullnessAnalyzer.analyze(classInternalName, methodNode) + nullnessAnalyzer + } + + /** + * Instructions that match `query` when textified. + * If `query` starts with a `+`, the next instruction is returned. + */ + def findInstr(method: MethodNode, query: String): List[AbstractInsnNode] = { + val useNext = query(0) == '+' + val instrPart = if (useNext) query.drop(1) else query + val insns = method.instructions.iterator.asScala.find(i => textify(i) contains instrPart).toList + if (useNext) insns.map(_.getNext) else insns + } + + def testNullness(analyzer: NullnessAnalyzer, method: MethodNode, query: String, index: Int, nullness: Nullness): Unit = { + for (i <- findInstr(method, query)) { + val r = analyzer.frameAt(i, method).getValue(index).nullness + assertTrue(s"Expected: $nullness, found: $r. At instr ${textify(i)}", nullness == r) + } + } + + // debug / helper for writing tests + def showAllNullnessFrames(analyzer: NullnessAnalyzer, method: MethodNode): String = { + val instrLength = method.instructions.iterator.asScala.map(textify(_).length).max + val lines = for (i <- method.instructions.iterator.asScala) yield { + val f = analyzer.frameAt(i, method) + val frameString = { + if (f == null) "null" + else f.toString.split("NullnessValue").iterator + .map(_.trim).filter(_.nonEmpty) + .map(s => "%7s".format(s.replaceAll("""\((.*),false\)""", "$1"))) + .zipWithIndex.map({case (s, i) => s"$i: $s"}) + .mkString(", ") + } + ("%"+ instrLength +"s: %s").format(textify(i), frameString) + } + lines.mkString("\n") + } + + @Test + def showNullnessFramesTest(): Unit = { + val List(m) = compileMethods(noOptCompiler)("def f = this.toString") + + // NOTE: the frame for an instruction represents the state *before* executing that instr. + // So in the frame for `ALOAD 0`, the stack is still empty. + + val res = + """ L0: 0: NotNull + | LINENUMBER 1 L0: 0: NotNull + | ALOAD 0: 0: NotNull + |INVOKEVIRTUAL java/lang/Object.toString ()Ljava/lang/String;: 0: NotNull, 1: NotNull + | ARETURN: 0: NotNull, 1: Unknown + | L0: null""".stripMargin + assertTrue(showAllNullnessFrames(newNullnessAnalyzer(m), m) == res) + } + + @Test + def thisNonNull(): Unit = { + val List(m) = compileMethods(noOptCompiler)("def f = this.toString") + val a = newNullnessAnalyzer(m) + testNullness(a, m, "ALOAD 0", 0, NotNull) + } + + @Test + def instanceMethodCall(): Unit = { + val List(m) = compileMethods(noOptCompiler)("def f(a: String) = a.trim") + val a = newNullnessAnalyzer(m) + testNullness(a, m, "INVOKEVIRTUAL java/lang/String.trim", 1, Unknown) + testNullness(a, m, "ARETURN", 1, NotNull) + } + + @Test + def constructorCall(): Unit = { + val List(m) = compileMethods(noOptCompiler)("def f = { val a = new Object; a.toString }") + val a = newNullnessAnalyzer(m) + + // for reference, the output of showAllNullnessFrames(a, m) - note that the frame represents the state *before* executing the instr. + // NEW java/lang/Object: 0: NotNull, 1: Unknown + // DUP: 0: NotNull, 1: Unknown, 2: Unknown + // INVOKESPECIAL java/lang/Object.<init>: 0: NotNull, 1: Unknown, 2: Unknown, 3: Unknown + // ASTORE 1: 0: NotNull, 1: Unknown, 2: NotNull + // ALOAD 1: 0: NotNull, 1: NotNull + // INVOKEVIRTUAL java/lang/Object.toString: 0: NotNull, 1: NotNull, 2: NotNull + // ARETURN: 0: NotNull, 1: NotNull, 2: Unknown + + for ((insn, index, nullness) <- List( + ("+NEW", 2, Unknown), // new value at slot 2 on the stack + ("+DUP", 3, Unknown), + ("+INVOKESPECIAL java/lang/Object", 2, NotNull), // after calling the initializer on 3, the value at 2 becomes NotNull + ("ASTORE 1", 1, Unknown), // before the ASTORE 1, nullness of the value in local 1 is Unknown + ("+ASTORE 1", 1, NotNull), // after storing the value at 2 in local 1, the local 1 is NotNull + ("+ALOAD 1", 2, NotNull), // loading the value 1 puts a NotNull value on the stack (at 2) + ("+INVOKEVIRTUAL java/lang/Object.toString", 2, Unknown) // nullness of value returned by `toString` is Unknown + )) testNullness(a, m, insn, index, nullness) + } + + @Test + def explicitNull(): Unit = { + val List(m) = compileMethods(noOptCompiler)("def f = { var a: Object = null; a }") + val a = newNullnessAnalyzer(m) + for ((insn, index, nullness) <- List( + ("+ACONST_NULL", 2, Null), + ("+ASTORE 1", 1, Null), + ("+ALOAD 1", 2, Null) + )) testNullness(a, m, insn, index, nullness) + } + + @Test + def stringLiteralsNotNull(): Unit = { + val List(m) = compileMethods(noOptCompiler)("""def f = { val a = "hi"; a.trim }""") + val a = newNullnessAnalyzer(m) + testNullness(a, m, "+ASTORE 1", 1, NotNull) + } + + @Test + def newArraynotNull() { + val List(m) = compileMethods(noOptCompiler)("def f = { val a = new Array[Int](2); a(0) }") + val a = newNullnessAnalyzer(m) + testNullness(a, m, "+NEWARRAY T_INT", 2, NotNull) // new array on stack + testNullness(a, m, "+ASTORE 1", 1, NotNull) // local var (a) + } + + @Test + def aliasBranching(): Unit = { + val code = + """def f(o: Object) = { + | var a: Object = o // a and o are aliases + | var b: Object = null + | var c: Object = null + | var d: Object = o + | if ("".trim == "") { + | b = o + | c = o // a, o, b, aliases + | d = null + | } else { + | b = a // a, o, b aliases + | d = null + | } + | b.toString // a, o, b aliases (so they become NotNull), but not c + | // d is null here, assinged in both branches. + |} + """.stripMargin + val List(m) = compileMethods(noOptCompiler)(code) + val a = newNullnessAnalyzer(m) + + val trim = "INVOKEVIRTUAL java/lang/String.trim" + val toSt = "INVOKEVIRTUAL java/lang/Object.toString" + val end = s"+$toSt" + for ((insn, index, nullness) <- List( + (trim, 0, NotNull), // this + (trim, 1, Unknown), // parameter o + (trim, 2, Unknown), // a + (trim, 3, Null), // b + (trim, 4, Null), // c + (trim, 5, Unknown), // d + + (toSt, 2, Unknown), // a, still the same + (toSt, 3, Unknown), // b, was re-assinged in both branches to Unknown + (toSt, 4, Unknown), // c, was re-assigned in one branch to Unknown + (toSt, 5, Null), // d, was assigned to null in both branches + + (end, 2, NotNull), // a, NotNull (alias of b) + (end, 3, NotNull), // b, receiver of toString + (end, 4, Unknown), // c, no change (not an alias of b) + (end, 5, Null) // d, no change + )) testNullness(a, m, insn, index, nullness) + } +} |