Don't inlinie if the resulting method becomes too large for the JVM

This threshold is really the last resort and should never be reached.
An inlining heuristic that blows up methods to the maximum size
allowed by the JVM is broken.

In the future we need to include some heuristic about code size when
making an inlining decision, see github.com/scala-opt/scala/issues/2

1 files changed, 8 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BackendReporting.scala b/src/compiler/scala/tools/nsc/backend/jvm/BackendReporting.scala
index 89cbbc793c..c15ed032fb 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/BackendReporting.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/BackendReporting.scala
@@ -214,10 +214,15 @@ object BackendReporting {
 
       case SynchronizedMethod(_, _, _) =>
         s"Method $calleeMethodSig cannot be inlined because it is synchronized."
+
+      case ResultingMethodTooLarge(_, _, _, callsiteClass, callsiteName, callsiteDesc) =>
+        s"""The size of the callsite method ${BackendReporting.methodSignature(callsiteClass, callsiteName, callsiteDesc)}
+           |would exceed the JVM method size limit after inlining $calleeMethodSig.
+         """.stripMargin
     }
 
     def emitWarning(settings: ScalaSettings): Boolean = this match {
-      case _: IllegalAccessInstruction | _: MethodWithHandlerCalledOnNonEmptyStack | _: SynchronizedMethod =>
+      case _: IllegalAccessInstruction | _: MethodWithHandlerCalledOnNonEmptyStack | _: SynchronizedMethod | _: ResultingMethodTooLarge =>
         settings.YoptWarningEmitAtInlineFailed
 
       case IllegalAccessCheckFailed(_, _, _, _, _, cause) =>
@@ -231,6 +236,8 @@ object BackendReporting {
   case class MethodWithHandlerCalledOnNonEmptyStack(calleeDeclarationClass: InternalName, name: String, descriptor: String,
                                                     callsiteClass: InternalName, callsiteName: String, callsiteDesc: String) extends CannotInlineWarning
   case class SynchronizedMethod(calleeDeclarationClass: InternalName, name: String, descriptor: String) extends CannotInlineWarning
+  case class ResultingMethodTooLarge(calleeDeclarationClass: InternalName, name: String, descriptor: String,
+                                     callsiteClass: InternalName, callsiteName: String, callsiteDesc: String) extends CannotInlineWarning
 
   /**
    * Used in the InlineInfo of a ClassBType, when some issue occurred obtaining the inline information.