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| author | Jason Zaugg <jzaugg@gmail.com> | 2014-05-18 12:01:17 +0200 |
|---|---|---|
| committer | Jason Zaugg <jzaugg@gmail.com> | 2014-05-18 12:04:27 +0200 |
| commit | 0b432f9cd22b6e9770852e5b331a15f0534a312c (patch) | |
| tree | 481b2a30ead8f171268d69f68b2506453eae9df8 | |
| parent | ee611cd76c29fedd416162e482c7ab3f15b831ca (diff) | |
| download | scala-0b432f9cd22b6e9770852e5b331a15f0534a312c.tar.gz scala-0b432f9cd22b6e9770852e5b331a15f0534a312c.tar.bz2 scala-0b432f9cd22b6e9770852e5b331a15f0534a312c.zip | |
SI-8601 Avoid over-eager optimization of LOAD_FIELD
It can NPE or trigger static class initilization, we can't elimiate
it without changing semantics.
| -rw-r--r-- | src/compiler/scala/tools/nsc/backend/opt/ClosureElimination.scala | 9 | ||||
| -rw-r--r-- | src/compiler/scala/tools/nsc/backend/opt/DeadCodeElimination.scala | 2 | ||||
| -rw-r--r-- | test/files/run/t8601c.flags | 1 | ||||
| -rw-r--r-- | test/files/run/t8601c.scala | 12 |
4 files changed, 18 insertions, 6 deletions
diff --git a/src/compiler/scala/tools/nsc/backend/opt/ClosureElimination.scala b/src/compiler/scala/tools/nsc/backend/opt/ClosureElimination.scala index c49f23852f..0b943360de 100644 --- a/src/compiler/scala/tools/nsc/backend/opt/ClosureElimination.scala +++ b/src/compiler/scala/tools/nsc/backend/opt/ClosureElimination.scala @@ -56,11 +56,10 @@ abstract class ClosureElimination extends SubComponent { case (BOX(t1), UNBOX(t2)) if (t1 == t2) => Some(Nil) - case (LOAD_FIELD(sym, isStatic), DROP(_)) if !sym.hasAnnotation(definitions.VolatileAttr) => - if (isStatic) - Some(Nil) - else - Some(DROP(REFERENCE(definitions.ObjectClass)) :: Nil) + // Can't eliminate (LOAD_FIELD, DROP) without eliding side effects: + // - static class initialization + // - NPE if the receiver is null + // We could replace the LOAD/DROP with a null check to preserve semantics. case _ => None } diff --git a/src/compiler/scala/tools/nsc/backend/opt/DeadCodeElimination.scala b/src/compiler/scala/tools/nsc/backend/opt/DeadCodeElimination.scala index 3c983e6fdf..64aed19bf0 100644 --- a/src/compiler/scala/tools/nsc/backend/opt/DeadCodeElimination.scala +++ b/src/compiler/scala/tools/nsc/backend/opt/DeadCodeElimination.scala @@ -167,7 +167,7 @@ abstract class DeadCodeElimination extends SubComponent { set += idx localStores(key) = set - case RETURN(_) | JUMP(_) | CJUMP(_, _, _, _) | CZJUMP(_, _, _, _) | STORE_FIELD(_, _) | + case RETURN(_) | JUMP(_) | CJUMP(_, _, _, _) | CZJUMP(_, _, _, _) | STORE_FIELD(_, _) | LOAD_FIELD(_, _) | // Why LOAD_FIELD? It can NPE! THROW(_) | LOAD_ARRAY_ITEM(_) | STORE_ARRAY_ITEM(_) | SCOPE_ENTER(_) | SCOPE_EXIT(_) | STORE_THIS(_) | LOAD_EXCEPTION(_) | SWITCH(_, _) | MONITOR_ENTER() | MONITOR_EXIT() | CHECK_CAST(_) => moveToWorkList() diff --git a/test/files/run/t8601c.flags b/test/files/run/t8601c.flags new file mode 100644 index 0000000000..1182725e86 --- /dev/null +++ b/test/files/run/t8601c.flags @@ -0,0 +1 @@ +-optimize
\ No newline at end of file diff --git a/test/files/run/t8601c.scala b/test/files/run/t8601c.scala new file mode 100644 index 0000000000..c487d6825e --- /dev/null +++ b/test/files/run/t8601c.scala @@ -0,0 +1,12 @@ +object Test { + def loadField(x: scala.runtime.IntRef): Unit = x.elem + def storeField(x: scala.runtime.IntRef): Unit = x.elem = 42 + + def check(x: => Any) = try { x; sys.error("failed to throw NPE!") } catch { case _: NullPointerException => } + + def main(args: Array[String]) { + check(loadField(null)) // bug: did not NPE under -Ydead-code + check(storeField(null)) + + } +} |