SD-48 limit the lenght of inlined local variable names

When inlining local variables, the names are prefixed with the callee
method name. In long chains of inlining, these names can grow
indefinitely. This commits introduces a limit.

1 files changed, 37 insertions, 0 deletions

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 f531ce9322..f88b95eae4 100644
--- a/test/junit/scala/tools/nsc/backend/jvm/opt/InlinerTest.scala
+++ b/test/junit/scala/tools/nsc/backend/jvm/opt/InlinerTest.scala
@@ -1587,4 +1587,41 @@ class InlinerTest extends BytecodeTesting {
     val List(c, t) = compile(code)
     assertNoIndy(getMethod(c, "t1"))
   }
+
+  @Test
+  def limitInlinedLocalVariableNames(): Unit = {
+    val code =
+      """class C {
+        |  def f(x: Int): Int = x
+        |  @inline final def methodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFrenchSentence(param: Int) =
+        |    f(param)
+        |  @inline final def anotherMethodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFrenchSentence(param: Int) =
+        |    methodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFrenchSentence(f(param))
+        |  @inline final def oneMoreMethodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFrenchSentence(param: Int) =
+        |    anotherMethodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFrenchSentence(f(param))
+        |  @inline final def yetAnotherMethodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFrenchSentence(param: Int) =
+        |    oneMoreMethodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFrenchSentence(f(param))
+        |  @inline final def oneLastMethodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFrenchSentence(param: Int) =
+        |    yetAnotherMethodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFrenchSentence(f(param))
+        |  def t(p: Int) =
+        |    oneLastMethodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFrenchSentence(f(p)) +
+        |    oneLastMethodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFrenchSentence(f(p))
+        |}
+      """.stripMargin
+
+    val List(c) = compile(code)
+    assertEquals(getAsmMethod(c, "t").localVariables.asScala.toList.map(l => (l.name, l.index)).sortBy(_._2),List(
+      ("this",0),
+      ("p",1),
+      ("oneLastMethodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFrenchSentence_param",2),
+      ("oneLastMethodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFrenchS_yetAnotherMethodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFren_param",3),
+      ("oneLastMethodWithVeryVeryLongNameAlmostLik_yetAnotherMethodWithVeryVeryLongNameAlmost_oneMoreMethodWithVeryVeryLongNameAlmostLik_param",4),
+      ("oneLastMethodWithVeryVeryLongNam_yetAnotherMethodWithVeryVeryLong_oneMoreMethodWithVeryVeryLongNam_anotherMethodWithVeryVeryLongNam_param",5),
+      ("oneLastMethodWithVeryVery_yetAnotherMethodWithVeryV_oneMoreMethodWithVeryVery_anotherMethodWithVeryVery_methodWithVeryVeryLongNam_param",6),
+      ("oneLastMethodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFrenchSentence_param",7),
+      ("oneLastMethodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFrenchS_yetAnotherMethodWithVeryVeryLongNameAlmostLikeAGermanWordOrAFren_param",8),
+      ("oneLastMethodWithVeryVeryLongNameAlmostLik_yetAnotherMethodWithVeryVeryLongNameAlmost_oneMoreMethodWithVeryVeryLongNameAlmostLik_param",9),
+      ("oneLastMethodWithVeryVeryLongNam_yetAnotherMethodWithVeryVeryLong_oneMoreMethodWithVeryVeryLongNam_anotherMethodWithVeryVeryLongNam_param",10),
+      ("oneLastMethodWithVeryVery_yetAnotherMethodWithVeryV_oneMoreMethodWithVeryVery_anotherMethodWithVeryVery_methodWithVeryVeryLongNam_param",11)))
+  }
 }