From e994c1c0becddc0d91fd4428f0d673bfac8941a3 Mon Sep 17 00:00:00 2001 From: Jason Zaugg Date: Mon, 26 Sep 2016 09:47:49 +1000 Subject: SD-233 synchronized blocks are JIT-friendly again GenBCode, the new backend in Scala 2.12, subtly changed the way that synchronized blocks are emitted. It used `java/lang/Throwable` as an explicitly named exception type, rather than implying the same by omitting this in bytecode. This appears to confuse HotSpot JIT, which reports a error parsing the bytecode into its IR which leaves the enclosing method stuck in interpreted mode. This commit passes a `null` descriptor to restore the old pattern (the same one used by javac.) I've checked that the JIT warnings are gone and that the method can be compiled again. --- src/compiler/scala/tools/nsc/backend/jvm/BCodeSyncAndTry.scala | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'src/compiler/scala/tools/nsc/backend') diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BCodeSyncAndTry.scala b/src/compiler/scala/tools/nsc/backend/jvm/BCodeSyncAndTry.scala index 3e53419573..466793010f 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/BCodeSyncAndTry.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/BCodeSyncAndTry.scala @@ -73,9 +73,11 @@ abstract class BCodeSyncAndTry extends BCodeBodyBuilder { /* ------ (4) exception-handler version of monitor-exit code. * Reached upon abrupt termination of (2). * Protected by whatever protects the whole synchronized expression. + * null => "any" exception in bytecode, like we emit for finally. + * Important not to use j/l/Throwable which dooms the method to a life of interpretation! (SD-233) * ------ */ - protect(startProtected, endProtected, currProgramPoint(), jlThrowableRef) + protect(startProtected, endProtected, currProgramPoint(), null) locals.load(monitor) emit(asm.Opcodes.MONITOREXIT) emit(asm.Opcodes.ATHROW) -- cgit v1.2.3