Add support for non-byte-aligned bitstrings

CHANGELOG.md

@@ -28,6 +28,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added support for map comprehensions
 - Added USB CDC port drivers for ESP32, RP2, and STM32 platforms
 - Added a Linux `gpio` driver for the generic_unix port (in `avm_unix`) using sysfs
+- Added support for non-byte-aligned bitstrings, including with the legacy construction
+  opcodes emitted by OTP 26-27 with `no_bs_create_bin`, and added `erlang:bitstring_to_list/1`
 
 ### Changed
 - Updated network type db() to dbm() to reflect the actual representation of the type
@@ -64,12 +66,22 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed `ahttp_client` crash on non-numeric or negative `Content-Length` values
 - Fixed `ahttp_client` crash on headers with empty or all-whitespace values
 - Fixed a bug in `supervisor` handling of failing child
+- Fixed a one-byte out-of-bounds read and write in bit-granular bitstring copies, which could
+  touch the byte past an exactly-sized destination or source buffer
+- Fixed matching an `all`-sized segment with a non-power-of-two unit, which the JIT tested with an
+  `and` mask and rejected as unsupported
+- Fixed a `binary` segment accepting a non-byte-aligned bitstring source instead of raising `badarg`
 - Fixed two bugs related to closing fds in `atomvm:subprocess/4`
 - Fixed `erlang:localtime/1` memory leak, use-after-free, and TZ restore bugs on newlib/picolibc
 - Fixed ESP32 I2C driver resource leaks, half-closed state, and close-during-transmission errors
 - Fixed several underallocation issues that could trigger data corruption on `binary:replace`, `zlib:compress` and bsd socket recv code.
 - Fixed a bug where `catch` would raise on regular atom results
 - Fixed ESP32 socket driver holding the global socket-list lock across blocking TCP connects, leaking the port on connect failure, losing concurrent `accept` waiters, leaking `netbuf` on receive error paths, and a recycled-`netconn` race between socket close and the event handler
+- Fixed a negative dynamic segment size being scaled by the segment unit before validation, which
+  could let a match succeed with a wrapped-around size, and could move the match offset before the
+  start of the binary and crash under JIT
+- Fixed the JIT untagging small integers with a logical instead of an arithmetic shift, turning a
+  negative integer into a large positive one
 
 ## [0.7.0-alpha.1] - 2026-04-06
 

doc/src/apidocs/libatomvm/functions.rst

@@ -241,7 +241,6 @@ Functions
 .. doxygenfunction:: term_binary_heap_size
 .. doxygenfunction:: term_binary_size_is_heap_binary
 .. doxygenfunction:: term_boxed_size
-.. doxygenfunction:: term_bs_insert_binary
 .. doxygenfunction:: term_compare
 .. doxygenfunction:: term_create_empty_binary
 .. doxygenfunction:: term_create_uninitialized_binary

libs/estdlib/src/erlang.erl

@@ -71,6 +71,7 @@
     binary_to_integer/1,
     binary_to_integer/2,
     binary_to_list/1,
+    bitstring_to_list/1,
     atom_to_binary/1,
     atom_to_binary/2,
     atom_to_list/1,
@@ -151,6 +152,7 @@
     hd/1,
     is_atom/1,
     is_binary/1,
+    is_bitstring/1,
     is_boolean/1,
     is_float/1,
     is_function/1,
@@ -892,6 +894,21 @@ binary_to_integer(_Binary, _Base) ->
 binary_to_list(_Binary) ->
     erlang:nif_error(undefined).
 
+%%-----------------------------------------------------------------------------
+%% @param   Bitstring   Bitstring to convert to list
+%% @returns a list of bytes, with a final element holding the trailing bits if
+%%          `Bitstring' is not a whole number of bytes
+%% @doc     Convert a bitstring to a list of bytes.
+%%
+%%          If the number of bits in `Bitstring' is not divisible by `8', the
+%%          last element of the list is a bitstring containing the trailing
+%%          `1..7' bits, e.g. `bitstring_to_list(<<1:1>>)' returns `[<<1:1>>]'.
+%% @end
+%%-----------------------------------------------------------------------------
+-spec bitstring_to_list(Bitstring :: bitstring()) -> [byte() | bitstring()].
+bitstring_to_list(_Bitstring) ->
+    erlang:nif_error(undefined).
+
 %%-----------------------------------------------------------------------------
 %% @param   Atom        Atom to convert
 %% @returns a binary with the atom's name
@@ -1863,6 +1880,19 @@ is_atom(_Term) ->
 is_binary(_Term) ->
     erlang:nif_error(undefined).
 
+%%-----------------------------------------------------------------------------
+%% @param   Term  the term to test
+%% @returns `true' if `Term' is a bitstring; `false', otherwise.
+%% @doc     Return `true' if `Term' is a bitstring (including a binary);
+%%          `false', otherwise.
+%%
+%% This function may be used in a guard expression.
+%% @end
+%%-----------------------------------------------------------------------------
+-spec is_bitstring(Term :: term()) -> boolean().
+is_bitstring(_Term) ->
+    erlang:nif_error(undefined).
+
 %%-----------------------------------------------------------------------------
 %% @param   Term  the term to test
 %% @returns `true' if `Term' is a boolean (`true' or `false'); `false', otherwise.