From e4e5d08621137473674cf3cdce0b36a43a8d6d15 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Wed, 22 Aug 2012 14:54:45 +0200 Subject: compiler: Warn if the size of a binary segment is invalid The compiler would silently accept and Dialyzer would crash on code like: <> It is never acceptable for Dialyzer to crash. The compiler should at least generate a warning for such code. It is tempting to let the compiler generate an error, but that would mean that code like: Sz = 42.0, <>. would be possible to compile with optimizations disabled, but not with optimizations enabled. Dialyzer crashes because it calls cerl:bitstr_bitsize/1, which crashes if the type of size for the segment is invalid. The easiest way to avoid that crash is to extend the sanity checks in v3_core to also include the size field of binary segments. That will cause the compiler to issue a warning and to replace the bad binary construction with a call to erlang:error/1. (It also means that Dialyzer will not issue a warning for bad size fields.) --- lib/compiler/src/v3_core.erl | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'lib/compiler/src/v3_core.erl') diff --git a/lib/compiler/src/v3_core.erl b/lib/compiler/src/v3_core.erl index 242196c593..01042cc56f 100644 --- a/lib/compiler/src/v3_core.erl +++ b/lib/compiler/src/v3_core.erl @@ -823,6 +823,13 @@ bitstr({bin_element,_,E0,Size0,[Type,{unit,Unit}|Flags]}, St0) -> {_,_} -> throw(bad_binary) end, + case Size1 of + #c_var{} -> ok; + #c_literal{val=Sz} when is_integer(Sz), Sz >= 0 -> ok; + #c_literal{val=undefined} -> ok; + #c_literal{val=all} -> ok; + _ -> throw(bad_binary) + end, {#c_bitstr{val=E1,size=Size1, unit=#c_literal{val=Unit}, type=#c_literal{val=Type}, -- cgit v1.2.3