From af198c489a7ab431fd1e2b52d16e8e13525915f7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Thu, 10 Dec 2009 21:18:39 +0100 Subject: Fix crash in beam_bool The following code crashes beam_bool: bad(XDo1, XDo2, Do3) -> Do1 = (XDo1 =/= []), Do2 = (XDo2 =/= []), if Do1 =:= true; Do1 =:= false, Do2 =:= false, Do3 =:= delete -> no end. (Reported by Simon Cornish; minimized by Kostis Sagonas.) For the moment fix the bug in the simplest and safest way possible (basically, instead of crashing just don't do the optimization). In a future major release (e.g. R14), the following improvements could be considered: * In beam_bool, it should be possible to move the Do1 and Do2 expressions to the pre-block and still optimize the expression in the 'if' statement. * In sys_core_fold, it should be possible to eliminate the try/catch around the guard expression in the 'if', because none of the guard tests can actually fail. --- lib/compiler/test/andor_SUITE.erl | 36 ++++++++++++++++++++++++++++++++---- 1 file changed, 32 insertions(+), 4 deletions(-) (limited to 'lib/compiler/test/andor_SUITE.erl') diff --git a/lib/compiler/test/andor_SUITE.erl b/lib/compiler/test/andor_SUITE.erl index 34609a49f2..6e3ac4d4f4 100644 --- a/lib/compiler/test/andor_SUITE.erl +++ b/lib/compiler/test/andor_SUITE.erl @@ -20,13 +20,14 @@ -export([all/1, t_case/1,t_and_or/1,t_andalso/1,t_orelse/1,inside/1,overlap/1, - combined/1,in_case/1]). + combined/1,in_case/1,before_and_inside_if/1]). -include("test_server.hrl"). all(suite) -> test_lib:recompile(?MODULE), - [t_case,t_and_or,t_andalso,t_orelse,inside,overlap,combined,in_case]. + [t_case,t_and_or,t_andalso,t_orelse,inside,overlap,combined,in_case, + before_and_inside_if]. t_case(Config) when is_list(Config) -> %% We test boolean cases almost but not quite like cases @@ -380,6 +381,35 @@ in_case_1_guard(LenUp, LenDw, LenN, Rotation, Count) -> false -> loop end. +before_and_inside_if(Config) when is_list(Config) -> + ?line no = before_and_inside_if([a], [b], delete), + ?line no = before_and_inside_if([a], [b], x), + ?line no = before_and_inside_if([a], [], delete), + ?line no = before_and_inside_if([a], [], x), + ?line no = before_and_inside_if([], [], delete), + ?line yes = before_and_inside_if([], [], x), + ?line yes = before_and_inside_if([], [b], delete), + ?line yes = before_and_inside_if([], [b], x), + ok. + +%% Thanks to Simon Cornish and Kostis Sagonas. +%% Used to crash beam_bool. +before_and_inside_if(XDo1, XDo2, Do3) -> + Do1 = (XDo1 =/= []), + Do2 = (XDo2 =/= []), + if + %% This expression occurs in a try/catch (protected) + %% block, which cannot refer to variables outside of + %% the block that are boolean expressions. + Do1 =:= true; + Do1 =:= false, Do2 =:= false, Do3 =:= delete -> + no; + true -> + yes + end. + +%% Utilities. + check(V1, V0) -> if V1 /= V0 -> io:fwrite("error: ~w.\n", [V1]), @@ -393,5 +423,3 @@ echo(X) -> X. id(I) -> I. - - -- cgit v1.2.3