erlc bug: no_bs_match_state (OTP-R10B-10 / compiler-4.3.12)

Bjorn Gustavsson <>
Fri Apr 21 08:56:31 CEST 2006

Pascal Brisset <> writes:
> The problem also occurs whenever a guard allocates memory;
> for example "foo(<<Rest/binary>>) when Rest/=[0]".
> I'm not sure how this should be fixed.  The GC could scan the
> pointers in erts_mb and erts_save_mb.  Or the allocator could
> be prevented from relocating data while a binary match is in
> progress.

We have re-designed the bit syntax matching instructions in R11B
to resolve this issue (and a few others).

> Maybe earlier versions of erlc also generate "unsafe" code which
> goes unnoticed because they don't have beam_validator.  Or maybe
> there is no risk at all and the validator is too strict.

Yes, earlier version of the Erlang compiler did generate unsafe
code. The beam_validator is right.


Björn Gustavsson, Erlang/OTP, Ericsson AB

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