From 7d06e5ecd47ef071eb8c4e58ead70e79fa4b02b2 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Thu, 31 Mar 2016 06:55:31 +0200 Subject: Fix unsafe transformation of apply/3 with fixed arguments 62473daf introduced an unsafe optimization in the loader. See the comments in the test case for an explanation of the problem. --- erts/emulator/beam/beam_load.c | 7 +++++++ erts/emulator/beam/ops.tab | 2 +- 2 files changed, 8 insertions(+), 1 deletion(-) (limited to 'erts/emulator/beam') diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c index d3d278fb81..16cbdbffea 100644 --- a/erts/emulator/beam/beam_load.c +++ b/erts/emulator/beam/beam_load.c @@ -2734,6 +2734,13 @@ same_label(LoaderState* stp, GenOpArg Target, GenOpArg Label) Target.val == Label.val; } +static int +is_killed_apply(LoaderState* stp, GenOpArg Reg, GenOpArg Live) +{ + return Reg.type == TAG_x && Live.type == TAG_u && + Live.val+2 <= Reg.val; +} + static int is_killed(LoaderState* stp, GenOpArg Reg, GenOpArg Live) { diff --git a/erts/emulator/beam/ops.tab b/erts/emulator/beam/ops.tab index 9e53b4bfcc..772460c177 100644 --- a/erts/emulator/beam/ops.tab +++ b/erts/emulator/beam/ops.tab @@ -303,7 +303,7 @@ move_window5 x x x x x y # Swap registers. move R1=x Tmp=x | move R2=xy R1 | move Tmp R2 => swap_temp R1 R2 Tmp -swap_temp R1 R2 Tmp | line Loc | apply Live | is_killed(Tmp, Live) => \ +swap_temp R1 R2 Tmp | line Loc | apply Live | is_killed_apply(Tmp, Live) => \ swap R1 R2 | line Loc | apply Live swap_temp R1 R2 Tmp | line Loc | call Live Addr | is_killed(Tmp, Live) => \ -- cgit v1.2.3